- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

sh: Make return return from the closest function or dot script.

Formerly, return always returned from a function if it was called from a
function, even if there was a closer dot script. This was for compatibility
with the Bourne shell which only allowed returning from functions.

Other modern shells and POSIX return from the function or the dot script,
whichever is closest.

Git 1.8.4's rebase --continue depends on the POSIX behaviour.

Reported by: Christoph Mallon, avg

sh: Fix race condition with signals and wait or set -T.

The change in r238888 was incomplete. It was still possible for a trapped
signal to arrive before the shell went to sleep (sigsuspend()) because a
check was missing or because the signal arrived before in_waitcmd was set.

On SMP, this bug sometimes caused the builtins/wait4.0 test to take 1 second
to execute; it then might or might not fail. On UP, the test almost always
failed.

sh: Simplify list() in the parser.

The erflag argument was only used by old-style (``) command substitutions.
We can remove it and handle the special case in the command substitution
code.

sh: Separate out nbinary allocation into a function.

sh: Use makename() where possible.

sh: Add a function for the case where one token is required in the parse.

sh: Recognize "--" as end of options in type builtin.

This implementation makes minimal changes: command names starting with "-"
(other than "--") can still be queried normally.

sh: Cast -1 to pointer rather than pointer to variable of wrong type.

NEOF needs to be a non-null pointer distinct from valid union node pointers.
It is not dereferenced.

The new NEOF is much like SIG_ERR except that it is an object pointer
instead of a function pointer.

The variable tokpushback can now be static.

sh: Recognize "--" as end of options in alias builtin.

Aliases starting with "-" (which are non-POSIX) will need to be preceded by
an alias not starting with "-" or the newly added "--".

sh: Disallow empty simple commands.

As per POSIX, a simple command must have at least one redirection,
assignment word or command word.

These occured in rare cases such as eval "f()" .

The extension of allowing no commands inside { }, if, while, for, etc.
remains.

sh: Reject ++ and -- in arithmetic.

POSIX does not require ++ and -- in arithmetic. It is probably more useful
to reject them than to treat ++x and --x as x silently.

Note that the behaviour of increment and decrement can be obtained via
(x+=1), ((x+=1)-1), (x-=1) and ((x-=1)+1).

PR: bin/176444

sh: Do not prematurely discard stopped jobs in a wait builtin.

If a job is specified to 'wait', wait for it to complete. Formerly, in
interactive mode, the job was deleted if it stopped.

If no jobs are specified in interactive mode, 'wait' still waits for all jobs
to complete or stop.

In non-interactive mode, WUNTRACED is not passed to wait3() so stopped jobs
are not detected.

PR: bin/181435

sh: Remove unnecessary reset functions.

These are already handled by exception handlers.

sh: Recognize "--" as end of options in bg/fg/jobid builtins.

sh: Recognize "--" as end of options in local builtin.

sh: Allow a lone redirection before '|', ';;' or ';&'.

Example: </dev/null | :

PR: 181240
MFC after: 1 week

sh: Remove an incorrect comment.

sh: Remove #define MKINIT.

MKINIT only served for the removed mkinit. Many variables can be static now.

sh: Remove mkinit.

Replace the RESET blocks with regular functions and a reset() function that
calls them all.

This code generation tool is unusual and does not appear to provide much
benefit. I do not think isolating the knowledge about which modules need to
be reset is worth an almost 500-line build tool and wider scope for
variables used by the reset functions.

Also, relying on reset functions is often wrong: the cleanup should be done
in exception handlers so that no stale state remains after 'command eval'
and the like.

sh: Remove output.c's reset() handler.

These cleanup operations are not needed because they are already performed
after an optimized command substitution (whether there was an error or not).

sh: Do not read from stdin if an error occurs during -i -c cmd.

Although using -i with -c does not seem very useful, it seems inappropriate
to read commands from the terminal in this case.

Side effect: if the -s -c extension is used and the -s option is turned off
using 'set +s' during the interactive part, the shell now exits after an
error or interrupt. Note that POSIX only specifies -s as option to sh, not
to set.

See also Austin Group issue #718.

sh: Do not close(-1) if pipe() fails.

sh(1): A subshell environment has its own rlimits (ulimit).

This has always been the case and is intended (just like cd).

This matches Austin group issue #706.

sh(1): Document new features in wait builtin.

PR: 176916

sh: Return status 127 for unknown jobs in wait builtin.

This is required by POSIX, at least for pids that are not known child
processes.

Other problems with job specifications still cause wait to abort with
exit status 2.

PR: 176916

sh: Allow multiple operands in wait builtin.

This is only part of the PR; the behaviour for unknown/invalid pids/jobs
remains unchanged (aborts the builtin with status 2).

PR: 176916
Submitted by: Vadim Goncharov

sh: Remove linked list of stack marks.

The linked list of stack marks may cause problems if the allocation stack is
used between an exception and a higher-level popstackmark(), as it may then
touch a stack mark that is local to a function which has returned.

Also, the adjustment compares to a pointer passed to realloc(), which is
undefined behaviour.

Instead of adjusting stack marks when reallocating stack blocks, ensure that
such an adjustment is never necessary by fixing a small piece of memory in
place at a stack mark. This also simplifies the code.

To avoid the problems reported in bin/175922, it remains necessary to call
setstackmark() after popstackmark() if the stack mark remains in use.

Fix two typos

Reviewed by: jilles

sh: Use O_CLOEXEC and F_DUPFD_CLOEXEC instead of separate fcntl() call.

sh: Improve error handling in read builtin:

* If read -t times out, return status as if interrupted by SIGALRM
(formerly 1).
* If a trapped signal interrupts read, return status 128+sig (formerly 1).
* If [EINTR] occurs but there is no trap, retry the read (for example
because of a SIGWINCH in interactive mode).
* If a read error occurs, write an error message and return status 2.

As before, a variable assignment error returns 2 and discards the remaining
data read.

sh: Don't consider jobs -s/-p as reporting the status of jobs.

This ensures that something like j=$(jobs -p) does not prevent any
status from being written to the terminal.

Document a few expansions for the $PS1 and $PS2 environmental variables.

PR: 173410
Submitted by: Derek Wood <ddwood@outlook.com>
Reviewed by: jilles

sh: Don't modify exit status when break/continue/return passes !.

This matches what would happen if ! P were to be replaced with
if P; then false; else true; fi.

Example:
f() { ! return 0; }; f

sh: Add const to nodesavestr().

sh: Write as much into the heredoc pipe as possible, to avoid forking.

Use non-blocking I/O to write as much as the pipe will accept (often 64K,
but it can be as little as 4K), avoiding the need for the ugly PIPESIZE
constant. If PIPESIZE was set too high, a deadlock would occur.

sh: Fix various compiler warnings.

It now passes WARNS=7 with clang on i386.

GCC 4.2.1 does not understand setjmp() properly so will always trigger
-Wuninitialized. I will not add the volatile keywords to suppress this.

Minor mdoc fix.

sh(1): Mention possible ambiguities with $(( and ((.

In some other shells, things like $((a);(b)) are command substitutions.

Also, there are shells that have an extension ((ARITH)) that evaluates an
arithmetic expression and returns status 1 if the result is zero, 0
otherwise. This extension may lead to ambiguity with two subshells starting
in sequence.

sh: Recognize "--" and explicitly reject options in wait builtin.

If syntactically invalid job identifiers are to be taken as jobs that exited
with status 127, this should not apply to options, so that we can add
options later if need be.

sh: When executing a trap, keep exit status along with evalskip.

This ensures 'return' in a trap returns the correct status to the caller.

If evalskip is not set or if it is overridden by a previous evalskip, keep
the old behaviour of restoring the exit status from before the trap.

sh: If a SIGINT or SIGQUIT interrupts "wait", return status 128+sig.

sh: Fix a crash with the stackmark code.

If a stack mark is set while the current stack block is empty, the stack
block may move later on (because of realloc()) and the stack mark needs to
be updated. This updating does not happen after popstackmark() has been
called; therefore, call setstackmark() again if the stack mark is still
being used.

For some reason, this only affects a few users. I cannot reproduce it. The
situation seems quite rare as well because an empty stack block would
usually be freed (by popstackmark()) before execution reaches a
setstackmark() call.

PR: 175922
Tested by: KT Sin

sh: Simplify mksyntax and make it fit for cross-compiling.

Now it outputs fixed files, which use constants provided by the C standard
library to determine appropriate values for the target machine.

Before, mksyntax inspected the host machine which resulted in subtle
breakage if e.g. char is signed on the host and unsigned on the target such
as when cross-compiling on x86 for ARM.

Tested using -funsigned-char on amd64. Compiling build-tools without it and
sh itself with it causes various tests to fail without this change but not
with this change. With consistent -funsigned-char, tests pass with or
without this change.

The mksyntax program could be removed and syntax.c and syntax.h committed to
the repository.

Submitted by: Christoph Mallon
MFC after: 2 weeks

sh: Fix a comment.

Catch TRACE parameters up with r238888. This change is only needed when
debugging is enabled.

sh: Do not test for digit_contig in mksyntax.

ISO/IEC 9899:1999 (E) 5.2.1p3 guarantees that the values of the characters
0123456789 are contiguous.

The generated syntax.c and syntax.h remain the same.

Submitted by: Christoph Mallon

sh: Expand here documents in the current process.

Expand here documents at the same point other redirections are expanded but
use a non-fork subshell environment (like simple command substitutions) for
compatibility. Substitition errors result in an empty here document like
before.

As a result, a fork is avoided for short (<4K) expanded here documents.

Unexpanded here documents (with quoted end marker after <<) are not affected
by this change. They already only forked when >4K.

Side effects:
* Order of expansion is slightly different.
* Slow expansions are not executed in parallel with the redirected command.
* A non-fork subshell environment is subtly different from a forked process.

sh: Prefer our character classification functions to <ctype.h>.

sh: Show negated commands (!) in jobs output.

Add FILES section.

Discussed with: jilles

Change the $ENV example to use .shrc instead of .shinit. This is consistent
with what we use in /usr/share/skel/dot.profile.

Discussed with: jilles

sh: Move some stackmarks to fix high memory usage in some loops.

If a loop contained certain commands (such as redirected compound commands),
the temporary memory for the redirection was not freed between iterations of
the loop but only after the loop.

Put a stackmark in evaltree(), freeing memory whenever a node has been
evaluated. Some other stackmarks are then redundant; remove them.

Example:
while :; do { :; } </dev/null; done

sh: Remove mkinit's initialization routine.

Instead, call the only init function left directly from main().

sh: Replace an mkinit use with an initialization.

sh: Simplify cd-hash interaction.

Instead of rechecking relative paths for all hashed utilities after a cd,
track if any utility in cmdtable depends on a relative path in PATH.
If there is such a utility, cd clears the entire table.

As a result, the '*' in hash no longer happens.

sh: Pass $? to command substitution containing compound/multiple commands.

Example:
false; echo $(echo $?; :)

sh: Fix crash when parsing '{ } &'.

MFC after: 1 week

sh: Don't lose $? when backquoted command ends with semicolon or newline.

An empty simple command was added and overwrote the exit status with 0.

This affects `...` but not $(...).

Example:
v=`false;`; echo $?

sh: Prefer strsignal() to accessing sys_siglist directly.

Accessing sys_siglist directly requires rtld to copy it from libc to the sh
executable's BSS. Also, strsignal() will put in the signal number for
unknown signals (FreeBSD-specific) so we need not do that ourselves.

Unfortunately, there is no function for sys_signame.

sh: Detect and flag write errors on stdout in builtins.

If there is a write error on stdout, a message will be printed (to stderr)
and the exit status will be changed to 2 if it would have been 0 or 1.

PR: bin/158206

sh: Remove an unused variable.

sh: Forward-declare struct alias instead of giving up type safety via void *

sh: Fix two issues when an alias is redefined:

* The last character is not displayed.
* If the alias ends with itself (as a word), an infinite memory-eating loop
occurs.

If an alias is defined initially, a space is appended to avoid recursion but
this did not happen when an alias was later modified.

PR: bin/173418
Submitted by: Daniel F.
MFC after: 1 week

sh: Change cmdtype in tblentry from short to signed char.

If this is a smaller type than int anyway, we can make it the smallest
possible.

sh: Use C99 flexible array instead of accessing array beyond bounds.

Although sufficient memory is available for a longer string in cmdname,
this is undefined behaviour anyway.

Side effect: for alignment reasons, an additional byte of memory is
allocated per hashed command.

mdoc: don't nest displays. The markup here isn't adding anything anyway.
Fixes a mandoc lint warning.

Discussed with: brueffer, Jason McIntyre <jmc@kerhand.co.uk>

sh: Prefer internal nextopt() to libc getopt().

This reduces code duplication and code size.

/usr/bin/printf is not affected.

Side effect: different error messages when certain builtins are passed
invalid options.

sh: Reduce code duplication: use setinputfile instead of open/setinputfd
combination.

MFC after: 2 weeks

Minor mdoc fix.

sh: Remove XXX comment about removing nextopt().

Using nextopt() avoids depending on the BSD-specific optreset feature in
getopt() and reduces code size (both source and binary).

sh: Fix EINTR race condition in "wait" and "set -T" using sigsuspend().

When waiting for child processes using "wait" or if "set -T" is in effect, a
signal interrupts the wait. Make sure there is no window where the signal
handler may be invoked (setting a flag) just before going to sleep.

There is a similar race condition in the shell language, but scripts can
avoid it by exiting from the trap handler or enforcing synchronization using
a fifo.

If SIGCHLD is not trapped, a signal handler must be installed for it. Only
install this handler for the duration of the wait to avoid triggering
unexpected [EINTR] errors elsewhere.

Note that for some reason only SIGINT and SIGQUIT interrupt a "wait"
command. This remains the case.

sh: Do not ask for stopped/continued processes if we do not need them
rather than retrying wait3 if they happen.

sh: Inline waitproc() into its only caller.

sh: Track continued jobs (even if not continued by bg or fg).

This uses wait3's WCONTINUED flag.

There is no message for this. The change is visible in "jobs" or if the job
stops again.

sh: Reset pendingsigs before checking pending traps, not after.

Otherwise, a signal arriving at exactly the right moment might not be
processed until another signal arrived.

sh: Remove unused variable in_dowait.

sh: Expand assignment-like words specially for export/readonly/local.

Examples:
export x=~
now expands the tilde
local y=$1
is now safe, even if $1 contains IFS characters or metacharacters.

For a word to "look like an assignment", it must start with a name followed
by an equals sign, none of which may be quoted.

The special treatment applies when the first word (potentially after
"command") is "export", "readonly" or "local". There may be quoting
characters but no expansions. If "local" is overridden with a function there
is no special treatment ("export" and "readonly" cannot be overridden with a
function).

If things like
local arr=(1 2 3)
are ever allowed in the future, they cannot call a "local" function. This
would either be a run-time error or it would call the builtin.

This matches Austin Group bug #351, planned for the next issue of POSIX.1.

PR: bin/166771

Merge libedit adjustment from NetBSD.

On recent versions of NetBSD's libedit, el_gets
now sets el_len to -1 on error so we can
distinguish between a NULL string and an error.

This fixes sh from exiting with newer versions
of libedit now allowing EINTR to return.

Obtained from: NetBSD
Reviewed by: jilles
MFC after: 3 weeks

Work better with how make/bmake works:
1. Avoid a cd back into ${.CURDIR} to run mkbuiltins when we know make
will first cd into ${.OBJDIR}. Keep the cwd to what make sets it to.
2. Don't tell mkbuiltins where to write to (= ${.OBJDIR}), but where to
get sources from (= ${.CURDIR}). This to compensate for point 1.

This fixes a problem with bmake's mk files that optimize ${.OBJDIR} to
expand to "." after changing cwd, not taking into account that the
target is pretty much undoing that and not getting the full path to the
object tree anymore.

sh: Remove an unused header.

The read builtin no longer does things with termios.

Minor mdoc nits.

mdoc: fix column names, indentation, column separation within each row, and
quotation. Also make sure we have the same amount of columns in each row as
the number of columns we specify in the head arguments.

Reviewed by: brueffer

sh: Fix build with -DDEBUG=2.

Reported by: Kristof Provost
MFC after: 1 week

Remove trailing whitespace per mdoc lint warning

Disussed with: gavin
No objection from: doc
Approved by: joel
MFC after: 3 days

Remove superfluous paragraph macro.

sh: Make 'hash' return 1 if at least one utility is not found.

Reported by: lme

sh: Fix swapped INTON/INTOFF.

A possible consequence of this bug was a memory leak if SIGINT arrived
during a 'set' command (listing variables).

MFC after: 1 week

sh: Use vfork in a few common cases.

This uses vfork() for simple commands and command substitutions containing a
single simple command, invoking an external program under certain conditions
(no redirections or variable assignments, non-interactive shell, no job
control). These restrictions limit the amount of code executed in a vforked
child.

There is a large speedup (for example 35%) in microbenchmarks. The
difference in buildkernel is smaller (for example 0.5%) but still
statistically significant. See
http://lists.freebsd.org/pipermail/freebsd-hackers/2012-January/037581.html
for some numbers.

The use of vfork() can be disabled by setting a variable named
SH_DISABLE_VFORK.

Add prototypes, ANSIfy functions definitions to reduce WARNS=6 output.

sh: Fix $? in the first command of a 'for'.

In the first command of a 'for', $? should be the exit status of the last
pipeline (command substitution in the word list or command before 'for'),
not always 0.

sh: Remove "kill" example function, which is superseded by the kill builtin

MFC after: 1 week

sh: Fix execution of multiple statements in a trap when evalskip is set

Before this fix, only the first statement of the trap was executed if
evalskip was set. This is for example the case when:
o "-e" is set for this shell
o a trap is set on EXIT
o a function returns 1 and causes the script to abort

Reviewed by: jilles
MFC after: 2 weeks

sh: Fix some bugs with exit status from case containing ;&.

Also, rework evalcase() to not evaluate any tree. Instead, return the
NCLISTFALLTHRU node and handle it in evaltree().

Fixed bugs:

* If a ;& list with non-zero exit status is followed by an empty ;; or final
list, the exit status of the case command should be equal to the exit
status of the ;& list, not 0.

* An empty ;& case should not reset $?.

sh: Fix two bugs with case and exit status:

* If no pattern is matched, POSIX says the exit status shall be 0 (even if
there are command substitutions).
* If a pattern is matched and there are no command substitutions, the first
command should see the $? from before the case command, not always 0.

sh: Change input buffer size from 1023 to 1024.

PR: bin/161756

sh: Fix out of bounds array access when trap is used with an invalid signal.

MFC after: 1 week

sh: Properly show "Not a directory" error in cd builtin.

The errno message display added in r222292 did not take attempting to
cd to a non-directory or something that cannot be stat()ed into account.

PR: bin/164070
MFC after: 10 days

sh: Make various functions static.

sh: Remove unused function scopyn().

sh: Make patmatch() non-recursive.

sh: Allow quoting ^ and ] in bracket expressions.

sh: Use dirent.d_type in pathname generation.

This improves performance for globs where a slash or another component
follows a component with metacharacters by eliminating unnecessary attempts
to open directories that are not.

sh: Cache de->d_namlen in a local variable.

sh: Do not force special builtins non-special in optimized command subst.

This is not necessary: errors are already caught in evalbackcmd() and
forcelocal handles changes to variables.

Note that this depends on r223024.

MFC after: 4 weeks

sh: Remove impossible evalskip check in 'for'.

sh: Reduce one level of evaltree() recursion when executing 'case'.
Free expanded case text before executing commands.
Remove impossible evalskip checks (expanding an argument cannot set
evalskip anymore since $(break) and the like are properly executed in a
subshell environment).

sh: Allow unsetting OPTIND.

Note that only assigning the decimal value 1 resets getopts, as before.

sh: Remove undefined behaviour due to overflow in +/-/* in arithmetic.

With i386 base gcc and i386 base clang, arith_yacc.o remains unchanged.

sh(1): Improve documentation of field splitting.

sh(1): Extend documentation about subshells.

Because sh executes commands in subshell environments without forking in
more and more cases (particularly from 8.0 on), it makes sense to describe
subshell environments more precisely using ideas from POSIX, together with
some FreeBSD-specific items.

In particular, the hash and times builtins may not behave as if their state
is copied for a subshell environment while leaving the parent shell
environment unchanged.

sh: Include <limits.h> instead of non-standard <sys/limits.h>.

sh(1): Improve documentation of shell patterns:

* Shell patterns are also for ${var#pat} and the like.
* An '!' by itself will not trigger pathname generation so do not call it a
meta-character, even though it has a special meaning directly after an
'['.
* Character ranges are locale-dependent.
* A '^' will complement a character class like '!' but is non-standard.

MFC after: 1 week

sh(1): Document the case command better.

Suggested by: netchild
Reviewed by: gjb

Remove duplicated header files

sh: Remove special support for background simple commands.

It expands the arguments in the parent shell process, which is incorrect.

sh: Add do-nothing -h option.

POSIX requires a -h option to sh and set, to locate and remember utilities
invoked by functions as they are defined. Given that this
locate-and-remember process is optional elsewhere, it seems safe enough to
make this option do nothing.

POSIX does not specify a long name for this option. Follow ksh in calling it
"trackall".

sh: Add case statement fallthrough (with ';&' instead of ';;').

Replacing ;; with the new control operator ;& will cause the next list to be
executed as well without checking its pattern, continuing until a list ends
with ;; or until the end of the case statement. This is like omitting
"break" in a C "switch" statement.

The sequence ;& was formerly invalid.

This feature is proposed for the next POSIX issue in Austin Group issue
#449.

sh: Skip variables with invalid names in "set", "export -p", "readonly -p".

This ensures the output of these commands is valid shell input.

sh: Reduce unnecessary forks with eval.

The eval special builtin now runs the code with EV_EXIT if it was run
with EV_EXIT itself.

In particular, this eliminates one fork when a command substitution contains
an eval command that ends with an external program or a subshell.

This is similar to what r220978 did for functions.

sh: Add support for named character classes in bracket expressions.

Example:
case x in [[:alpha:]]) echo yes ;; esac

sh: Fix duplicate prototypes for builtins.

Have mkbuiltins write the prototypes for the *cmd functions to builtins.h
instead of builtins.c and include builtins.h in more .c files instead of
duplicating prototypes for *cmd functions in other headers.

sh: Save/restore changed variables in optimized command substitution.

In optimized command substitution, save and restore any variables changed by
expansions (${var=value} and $((var=assigned))), instead of trying to
determine if an expansion may cause such changes.

If $! is referenced in optimized command substitution, do not cause jobs to
be remembered longer.

This fixes $(jobs $!) again, simplifies the man page and shortens the code.

sh: Fix locale-dependent ranges in bracket expressions.

When I added UTF-8 support in r221646, the LC_COLLATE-based ordering broke
because of sign extension of char.

Because of libc restrictions, this does not work for UTF-8. For UTF-8
locales, ranges always use character code order.

sh: Read .profile from the home directory (or / if HOME is not set).

In most cases, login shells are started from the home directory, but not in
all, such as xterm -ls.

This commit depends on r222957 for read_profile() performing parameter
expansion.

PR: bin/50569

sh: Do parameter expansion on ENV before using it.

This is required by POSIX, and allows things like ENV=\$HOME/.shrc.

Note that tilde expansion is explicitly not performed.

sh: Do parameter expansion before printing PS4 (set -x).

The function name expandstr() and the general idea of doing this kind of
expansion by treating the text as a here document without end marker is from
dash.

All variants of parameter expansion and arithmetic expansion also work (the
latter is not required by POSIX but it does not take extra code and many
other shells also allow it).

Command substitution is prevented because I think it causes too much code to
be re-entered (for example creating an unbounded recursion of trace lines).

Unfortunately, our LINENO is somewhat crude, otherwise PS4='$LINENO+ ' would
be quite useful.

sh: Fix $? in heredocs on simple commands.

PR: bin/41410

sh: Improve error message if the script cannot be opened.

Avoid "<nosuchfile>: cannot open <nosuchfile>: ...".

sh: Reduce more needless differences between error messages.

sh: Honour -n while processing -c string.

sh: Remove the "exp" builtin.

The "exp" builtin is undocumented, non-standard and not very useful.

If exp's return value is not used, something like
VAR=$(exp EXPRESSION)
is equivalent to
VAR=$((EXPRESSION))
except that errors in the expression are fatal and quoting special
characters is not needed in the latter case.

If exp's return value is used, something like
if exp EXPRESSION >/dev/null
can be replaced by
if [ $((EXPRESSION)) -ne 0 ]
with similar differences.

The exp-run showed that "let" is close enough to bash's and ksh's builtin
that removing it would break a few ports. Therefore, "let" remains in 9.x.

PR: bin/104432
Exp-run done by: pav (with some other sh(1) changes)

sh: Correct criterion for using CDPATH in cd.

CDPATH should be ignored not only for pathnames starting with '/' but also
for pathnames whose first component is '.' or '..'.

The man page already describes this behaviour.

sh: Various updates to the TOUR document.

sh: Fix unquoted $@/$* if IFS=''.

If IFS is null, unquoted $@/$* should still expand to separate words.
This differs from quoted $@ (which does not depend on IFS) in that pathname
generation is performed and empty words are removed.

sh: Show errno messages in cd.

sh: Remove obsolete token type TENDBQUOTE.

This token type was related to Almquist's original version of backquotes
that could not nest and fell into disuse fairly soon.

Fix some typos under bin/

Found by: codespell

sh: Fix bss-based buffer overflow in . builtin.

If the length of a directory in PATH together with the given filename
exceeded FILENAME_MAX (which may happen even for pathnames that work), a
static buffer was overflown.

The static buffer is unnecessary, we can use the stalloc() stack.

Obtained from: NetBSD
MFC after: 1 week

sh: Expand aliases after assignments and redirections.

sh: Implement the cd -e flag proposed for the next POSIX issue.

This reflects failure to determine the pathname of the new directory in the
exit status (1). Normally, cd returns successfully if it did chdir() and the
call was successful.

In POSIX, -e only has meaning with -P; because our -L is not entirely
compliant and may fall back to -P mode, -e has some effect with -L as well.

sh: Allow terminating a heredoc with a terminator at EOF without a newline.

This is sometimes used with eval or old-style command substitution, and most
shells other than ash derivatives allow it.

It can also be used with scripts that violate POSIX's requirement on the
application that they end in a newline (scripts must be text files except
that line length is unlimited).

Example:
v=`cat <<EOF
foo
EOF`
echo $v

This commit does not add support for the similar construct with new-style
command substitution, like
v=$(cat <<EOF
foo
EOF)
This continues to require a newline after the terminator.

sh: Minor optimization to output from ulimit/export/readonly.

No functional change is intended.

sh: Avoid close(-1) when evaluating a multi-command pipeline.

Valgrind complains about this.

sh: Add \u/\U support (in $'...') for UTF-8.

Because we have no iconv in base, support for other charsets is not
possible.

Note that \u/\U are processed using the locale that was active when the
shell started. This is necessary to avoid behaviour that depends on the
parse/execute split (for example when placing braces around an entire
script). Therefore, UTF-8 encoding is implemented manually.

sh: Optimize variable code by storing the length of the name.

Obtained from: NetBSD

sh(1): Update BUGS section for UTF-8 support.

sh: Add UTF-8 support to pattern matching.

?, [...] patterns match codepoints instead of bytes. They do not match
invalid sequences. [...] patterns must not contain invalid sequences
otherwise they will not match anything. This is so that ${var#?} removes the
first codepoint, not the first byte, without putting UTF-8 knowledge into
the ${var#pattern} code. However, * continues to match any string and an
invalid sequence matches an identical invalid sequence. (This differs from
fnmatch(3).)

sh: Add UTF-8 support to ${#var}.

If the current locale uses UTF-8, ${#var} counts codepoints (more precisely,
bytes b with (b & 0xc0) != 0x80).

sh: Track if the current locale's charset is UTF-8 or not.

sh: Change the CTL* bytes to ones invalid in UTF-8.

This ensures that mbrtowc(3) can be used directly once it has been verified
that there is no CTL* byte. Dealing with a CTLESC byte within a multibyte
character would be complicated.

The new values do occur in iso-8859-* encodings. This decreases efficiency
slightly but should not affect correctness.

Caveat: Updating across this change and rebuilding without cleaning may
yield a subtly broken sh binary. By default, make buildworld will clean and
avoid problems.

sh: Add $'quoting' (C-style escape sequences).

A string between $' and ' may contain backslash escape sequences similar to
the ones in a C string constant (except that a single-quote must be escaped
and a double-quote need not be). Details are in the sh(1) man page.

This construct is useful to include unprintable characters, tabs and
newlines in strings; while this can be done with a command substitution
containing a printf command, that needs ugly workarounds if the result is to
end with a newline as command substitution removes all trailing newlines.

The construct may also be useful in future to describe unprintable
characters without needing to write those characters themselves in 'set -x',
'export -p' and the like.

The implementation attempts to comply to the proposal for the next issue of
the POSIX specification. Because this construct is not in POSIX.1-2008,
using it in scripts intended to be portable is unwise.

Matching the minimal locale support in the rest of sh, the \u and \U
sequences are currently not useful.

Exp-run done by: pav (with some other sh(1) changes)

sh: Apply set -u to variables in arithmetic.

Note that this only applies to variables that are actually used.
Things like (0 && unsetvar) do not cause an error.

Exp-run done by: pav (with some other sh(1) changes)

sh: Detect an error for ${#var<GARBAGE>}.

In particular, this makes things like ${#foo[0]} and ${#foo[@]} errors
rather than silent equivalents of ${#foo}.

PR: bin/151720
Submitted by: Mark Johnston
Exp-run done by: pav (with some other sh(1) changes)

sh: Set $? to 0 for background commands.

For backgrounded pipelines and subshells, the previous value of $? was being
preserved, which is incorrect.

For backgrounded simple commands containing a command substitution, the
status of the last command substitution was returned instead of 0.

If fork() fails, this is an error.

sh: Check setuid()/setgid() return values.

If the -p option is turned off, privileges from a setuid or setgid binary
are dropped. Make sure to check if this succeeds. If it fails, this is an
error which will cause the shell to abort except in interactive mode or if
'command' was used to make 'set' or an outer 'eval' or '.' non-special.

Note that taking advantage of this feature and writing setuid shell scripts
seems unwise.

MFC after: 1 week

sh: Remove duplicate code resetting uid/gid for set +p/+o privileged.

MFC after: 1 week

sh: Allow EV_EXIT through function calls, make {...} <redir more consistent.

If EV_EXIT causes an exit, use the exception mechanism to unwind
redirections and local variables. This way, if the final command is a
redirected command, an EXIT trap now executes without the redirections.

Because of these changes, EV_EXIT can now be inherited by the body of a
function, so do so. This means that a function no longer prevents a fork
before an exec being skipped, such as in
f() { head -1 /etc/passwd; }; echo $(f)

Wrapping a single builtin in a function may still cause an otherwise
unnecessary fork with command substitution, however.

An exit command or -e failure still invokes the EXIT trap with the
original redirections and local variables in place.

Note: this depends on SHELLPROC being gone. A SHELLPROC depended on
keeping the redirections and local variables and only cleaning up the
state to restore them.

sh: Do not word split "${#parameter}".

This is only a problem if IFS contains digits, which is unusual but valid.

Because of an incorrect fix for PR bin/12137, "${#parameter}" was treated
as ${#parameter}. The underlying problem was that "${#parameter}"
erroneously added CTLESC bytes before determining the length. This
was properly fixed for PR bin/56147 but the incorrect fix was not backed
out.

Reported by: Seeker on forums.freebsd.org
MFC after: 2 weeks

sh(1): Describe subshell environment, command substitution more correctly.

POSIX does not require the shell to fork for a subshell environment, and we
use that possibility in various ways (command substitutions with a single
command and most subshells that are the final command of a shell process).
Therefore do not tie subshells to forking in the man page.

Command substitutions with expansions are a bit strange, causing a fork for
$(...$(($x))...) because $x might expand to y=2; they will probably be
changed later but this is how they work now.

sh: Fix some parameter expansion variants ${#...}.

These already worked: $# ${#} ${##} ${#-} ${#?}
These now work as well: ${#+word} ${#-word} ${##word} ${#%word}

There is an ambiguity in the standard with ${#?}: it could be the length of
$? or it could be $# giving an error in the (impossible) case that it is not
set. We continue to use the former interpretation as it seems more useful.

Remove unnecessary cast.

Reviewed by: jilles

sh(1): Reduce excessive semicolon-separated sentences.

Reported by: Benjamin Kaduk

sh: Fix some warnings in code for arithmetic expressions.

Submitted by: eadler

Fix typos - remove duplicate "the".

PR: bin/154928
Submitted by: Eitan Adler <lists at eitanadler.com>
MFC after: 3 days

sh: Detect dividing the smallest integer by -1.

This overflows and on some architectures such as amd64 it generates SIGFPE.
Generate an error on all architectures.

sh(1): Update description of arithmetic.

sh: Import arithmetic expression code from dash.

New features:
* proper lazy evaluation of || and &&
* ?: ternary operator
* executable is considerably smaller (8K on i386) because lex and yacc are
no longer used

Differences from dash:
* arith_t instead of intmax_t
* imaxdiv() not used
* unset or null variables default to 0
* let/exp builtin (undocumented, will probably be removed later)

Obtained from: dash

sh: Fix two things about {(...)} <redir:

* In {(...) <redir1;} <redir2, do not drop redir1.
* Maintain the difference between (...) <redir and {(...)} <redir:
In (...) <redir, the redirection is performed in the child, while in
{(...)} <redir it should be performed in the parent (like {(...); :;}
<redir)

sh: Remove clearcmdentry()'s now unused argument.

sh: Forget all cached command locations on any PATH change.

POSIX requires this and it is simpler than the previous code that remembered
command locations when appending directories to PATH.

In particular,
PATH=$PATH
is no longer a no-op but discards all cached command locations.

sh: Do not try to execute binary files as scripts.

If execve() returns an [ENOEXEC] error, check if the file is binary before
trying to execute it using sh. A file is considered binary if at least one
of the first 256 bytes is '\0'.

In particular, trying to execute ELF binaries for the wrong architecture now
fails with an "Exec format error" message instead of syntax errors and
potentially strange results.

sh: Remove special code for shell scripts without magic number.

These are called "shell procedures" in the source.

If execve() failed with [ENOEXEC], the shell would reinitialize itself
and execute the program as a script. This requires a fair amount of code
which is not frequently used (most scripts have a #! magic number).
Therefore just execute a new instance of sh (_PATH_BSHELL) to run the
script.

Make sys_signame upper case.

This matches the constants from <signal.h> with 'SIG' removed, which POSIX
requires kill and trap to accept and 'kill -l' to write.

'kill -l', 'trap', 'trap -l' output is now upper case.

In Turkish locales, signal names with an upper case 'I' are now accepted,
while signal names with a lower case 'i' are no longer accepted, and the
output of 'killall -l' now contains proper capital 'I' without dot instead
of a dotted capital 'I'.

sh: Return only 126 or 127 for execve() failures.

Do not return 2 for errors other than [EACCES] or [ENOENT].

sh: Remove comment mentioning herefd, which is gone.

sh: Send messages about signals to stderr.

This is required by POSIX and seems to make more sense.

See also r217557.

sh: Clean up some old comments:
* There is no plan for an alternative to the command "set".
* Attempting to unset a readonly variable has not raised an error for quite
a while, so the order of unsetting a variable and a function with the same
name does not matter.

MFC after: 1 week

sh: Fix signal messages being sent to the wrong file sometimes.

When a foreground job exits on a signal, a message is printed to stdout
about this. The buffer was not flushed after this which could result in the
message being written to the wrong file if the next command was a builtin
and had stdout redirected.

Example:
sh -c 'kill -9 $$'; : > foo; echo FOO:; cat foo

Reported by: gcooper
MFC after: 1 week

sh(1): Document changes to 'exit' from traps.

sh: If exit is used without args from a trap action, exit on the signal.

This is useful so that it is easier to exit on a signal than to reset the
trap to default and resend the signal. It matches ksh93. POSIX says that
'exit' without args from a trap action uses the exit status from the last
command before the trap, which is different from 'exit $?' and matches this
if the previous command is assumed to have exited on the signal.

If the signal is SIGSTOP, SIGTSTP, SIGTTIN or SIGTTOU, or if the default
action for the signal is to ignore it, a normal _exit(2) is done with exit
status 128+signal_number.

sh: Fix some things about -- in trap:
* Make 'trap --' do the same as 'trap' instead of nothing.
* Make '--' stop option processing (note that '-' action is not an option).

Side effect: The error message for an unknown option is different.

sh: Make 'trap -l' look like 'kill -l'.

sh: Follow-up to r216743, grabstackblock() can be replaced with stalloc().

grabstackblock() was used only once (but it is a very often executed piece
of code).

sh: Remove special %builtin PATH entry.
All builtins are now always found before a PATH search.

Most ash derivatives have an undocumented feature where the presence of an
entry "%builtin" in $PATH will cause builtins to be checked at that point of
the PATH search, rather than before looking at any directories as documented
in the man page (very old versions do document this feature).

I am removing this feature from sh, as it complicates the code, may violate
expectations (for example, /usr/bin/alias is very close to a forkbomb with
PATH=/usr/bin:%builtin, only /usr/bin/builtin not being another link saves
it) and appears to be unused (all the %builtin google code search finds is
in some sort of ash source code).

Note that aliases and functions took and take precedence above builtins.
Because aliases work on a lexical level they can only ever be overridden on
a lexical level (quoting or preceding 'builtin' or 'command'). Allowing
override of functions via PATH does not really fit in the model of sh and it
would work differently from %builtin if implemented.

Note: POSIX says special builtins are found before functions. We comply to
this because we do not allow functions with the same name as a special
builtin.

Silence from: freebsd-hackers@ (message sent 20101225)
Discussed with: dougb

sh: Make exit without parameters from EXIT trap POSIX-compliant.

It should use the original exit status, just like falling off the
end of the trap handler.

Outside an EXIT trap, 'exit' is still equivalent to 'exit $?'.

sh: Do not call exitshell() from evalcommand() unless evalcommand() forked
itself.

This ensures that certain traps caused by builtins are executed.

sh: Check readonly status for assignments on regular builtins.

An error message is written, the builtin is not executed, nonzero exit
status is returned but the shell does not abort.

This was already checked for special builtins and external commands, with
the same consequences except that the shell aborts for special builtins.

Obtained from: NetBSD

sh: Check if dup2 for redirection from/to a file succeeds.

A failure (e.g. caused by ulimit -n being set very low) is a redirection
error.

Example:
ulimit -n 9; exec 9<.

sh: Avoid side effects from builtins in optimized command substitution.

Change the criterion for builtins to be safe to execute in the same process
in optimized command substitution from a blacklist of only cd, . and eval to
a whitelist.

This avoids clobbering the main shell environment such as by $(exit 4) and
$(set -x).

The builtins jobid, jobs, times and trap can still show information not
available in a child process; this is deliberately permitted. (Changing
traps is not.)

For some builtins, whether they are safe depends on the arguments passed to
them. Some of these are always considered unsafe to keep things simple; this
only harms efficiency a little in the rare case they are used alone in a
command substitution.

sh: Properly restore exception handler in fc.

If SIGINT arrived at exactly the right moment (unlikely), an exception
handler in a no longer active stack frame would be called.

Because the old handler was not used in the normal path, clang thought it
was a dead value and if an exception happened it would longjmp() to garbage.
This caused builtins/fc1.0 to fail if histedit.c was compiled with clang.

MFC after: 1 week

sh: Don't do optimized command substitution if expansions have side effects.

Before considering to execute a command substitution in the same process,
check if any of the expansions may have a side effect; if so, execute it in
a new process just like happens if it is not a single simple command.

Although the check happens at run time, it is a static check that does not
depend on current state. It is triggered by:
- expanding $! (which may cause the job to be remembered)
- ${var=value} default value assignment
- assignment operators in arithmetic
- parameter substitutions in arithmetic except ${#param}, $$, $# and $?
- command substitutions in arithmetic

This means that $((v+1)) does not prevent optimized command substitution,
whereas $(($v+1)) does, because $v might expand to something containing
assignment operators.

Scripts should not depend on these exact details for correctness. It is also
imaginable to have the shell fork if and when a side effect is encountered
or to create a new temporary namespace for variables.

Due to the $! change, the construct $(jobs $!) no longer works. The value of
$! should be stored in a variable outside command substitution first.

sh: Make expansion errors in optimized command substitution non-fatal.
Command substitutions consisting of a single simple command are executed in
the main shell process but this should be invisible apart from performance
and very few exceptions such as $(trap).

sh: Simplify "stack string" code slightly.

Maintain a pointer to the end of the stack string area instead of how much
space is left. This simplifies the macros in memalloc.h. The places where
the new variable must be updated are only where the memory area is created,
destroyed or resized.

sh: Fix integer overflow check, it checked an uninitialized variable.

sh: Allow arbitrary large numbers in CHECKSTRSPACE.
Reduce "stack string" API somewhat and simplify code.
Add a check for integer overflow of the "stack string" length (probably
incomplete).

sh(1): Explain why it is a bad idea to use aliases in scripts.

sh: Add kill builtin.

This allows specifying a %job (which is equivalent to the corresponding
process group).

Additionally, it improves reliability of kill from sh in high-load
situations and ensures "kill" finds the correct utility regardless of PATH,
as required by POSIX (unless the undocumented %builtin mechanism is used).

Side effect: fatal errors (any error other than kill(2) failure) now return
exit status 2 instead of 1. (This is consistent with other sh builtins, but
not in NetBSD.)

Code size increases about 1K on i386.

Obtained from: NetBSD

sh: Add a function to print warnings (with command name and newline).
This is like error() but without raising an exception.
It is particularly useful as a replacement for the warnx macro in
bltin/bltin.h.

sh: Make warnings in the printf builtin non-fatal, like in the program.

The #define for warnx now behaves much like the libc function (except that
it uses sh command name and output).

Also, it now uses C99 __VA_ARGS__ so there is no need for three different
macros for 0, 1 or 2 parameters.

sh: arith: Disallow decimal constants starting with 0 (containing 8 or 9).

Constants in arithmetic starting with 0 should be octal only.

This avoids the following highly puzzling result:
$ echo $((018-017))
3
by making it an error instead.

Remove dead code.

c is assigned 0 and *loc is pointing to NULL, so c!=0 cannot be true,
and dereferencing loc would be a bad idea anyway.

Coverity Prevent: CID 5113
Reviewed by: jilles

sh: Fix corruption of command substitutions with special chars after newline

The CTLESC byte to protect a special character was output before instead of
after a newline directly preceding the special character.

The special handling of newlines is because command substitutions discard
all trailing newlines.

Remove duplicate check, turning dead code into live code.

Coverity CID: 5114
Reviewed by: jilles

sh: Various simplifications to jobs.c:
* Prefer kill(-X) to killpg(X).
* Remove some dead code.
* No additional SIGINT is needed if int_pending() is already true.

No functional change is intended.

sh: Remove the herefd hack.

The herefd hack wrote out partial here documents while expanding them. It
seems unnecessary complication given that other expansions just allocate
memory. It causes bugs because the stack is also used for intermediate
results such as arithmetic expressions. Such places should disable herefd
for the duration but not all of them do, and I prefer removing the need for
disabling herefd to disabling it everywhere needed.

Here documents larger than 1024 bytes will use a bit more CPU time and
memory.

Additionally this allows a later change to expand here documents in the
current shell environment. (This is faster for small here documents but also
changes behaviour.)

Obtained from: dash

sh: Replace some macros and repeated code in expand.c with functions.

No functional change is intended, but the binary is about 1K smaller on
i386.

sh: Use vsnprintf() rather than crafting our own in fmtstr().
Add INTOFF/INTON as longjmp out of vsnprintf may cause memory leaks or
undefined behaviour.

sh: Improve internal-representation-to-text code to avoid binary output.

The code to translate the internal representation to text did not know about
various additions to the internal representation since the original ash and
therefore wrote binary stuff to the terminal.

The code is used in the jobs command and similar output.

Note that the output is far from complete and mostly serves for recognition
purposes.

sh: POSIX says there should not be a space between Done and (exitstatus).

(On the other hand, (core dumped) does need a space and so does [1] +.)

sh: Improve jobs output of pipelines.

If describing the status of a pipeline, write all elements of the pipeline
and show the status of the last process (which would also end up in $?).
Only write one report per job, not one for every process that exits.

To keep some earlier behaviour, if any process started by the shell in a
foreground job terminates because of a signal, write a message about the
signal (at most one message per job, however).

Also, do not write messages about signals in the wait builtin in
non-interactive shells. Only true foreground jobs now write such messages
(for example, "Terminated").

sh: Avoid marking a job as done before it is fully created.

In r208489, I added code to reap zombies when forking new processes, to
limit the amount of zombies. However, this can lead to marking a job as done
or stopped if it consists of multiple processes and the first process ends
very quickly. Fix this by only checking for zombies before forking the first
process of a job and not marking any jobs without processes as done or
stopped.

sh: jobs -p: Do not ask the kernel for the pgid.

The getpgid() call will fail if the first process in the job has already
terminated, resulting in output of "-1".

The pgid of a job is always the pid of the first process in the job and
other code already relies on this.

sh(1): Clean up documentation of built-in commands.

Make sure all built-in commands are in the subsection named such, except
exp, let and wordexp which are deliberately undocumented. The text said only
built-ins that really need to be a built-in were documented there but in
fact almost all of them were already documented.

sh(1): Document that command's -p option also works with -v/-V.

This was implemented in r201343.

sh: Code size optimizations to "stack string" memory allocation:
* Prefer one CHECKSTRSPACE with multiple USTPUTC to multiple STPUTC.
* Add STPUTS macro (based on function) and use it instead of loops that add
nul-terminated strings to the stack string.

No functional change is intended, but code size is about 1K less on i386.

sh: Pass multiple bytes at a time to lex.

This speeds up the expansion/arith6.0 test considerably.

sh: Fix confusing behaviour if chdir succeeded but getcwd failed in cd -P.

If getcwd fails, do not treat this as an error, but print a warning and
unset PWD. This is similar to the behaviour when starting the shell in a
directory whose name cannot be determined.

Fix some more warnings found by clang.

sh: Remove the check that alpha/name/in_name chars are not CTL* bytes.

Since is_alpha/is_name/is_in_name were made ASCII-only, this can no longer
happen.

Additionally, the check was wrong because it did not include the new
CTLQUOTEEND.

sh: Code size optimizations to buffered output.

This is mainly less use of the outc macro.

No functional change is intended, but code size is about 2K less on i386.

sh: Add printf builtin.

This was removed in 2001 but I think it is appropriate to add it back:
* I do not want to encourage people to write fragile and non-portable echo
commands by making printf much slower than echo.
* Recent versions of Autoconf use it a lot.
* Almost no software still wants to support systems that do not have
printf(1) at all.
* In many other shells printf is already a builtin.

Side effect: printf is now always the builtin version (which behaves
identically to /usr/bin/printf) and cannot be overridden via PATH (except
via the undocumented %builtin mechanism).

Code size increases about 5K on i386. Embedded folks might want to replace
/usr/bin/printf with a hard link to /usr/bin/alias.

sh: Add binary buffered output for use by the printf builtin.

sh: Update the suspend example for the change of the job control flag
from -j to -m, many years ago.

Due to r215266, this function now actually works.

sh: Do the additional actions if 'local -' restore changes -i/-m/-E/-V.

Example:
f() { local -; set +m; }; f
caused failure to execute external programs because the job control tty fd
was not opened.

sh(1): Document r214304 (special builtin is illegal function name).

sh(1): Update for r214492. "${v+"hi}there"}".

The part hi}there is not a quoted string but nevertheless the closing brace
does not terminate the expansion.

sh: Remove unused man page for echo builtin.

The information in sh(1) about the echo builtin is equivalent, though less
extensive.

The echo(1) man page (bin/echo/echo.1) is different.

Unfortunately, sh's echo builtin and /bin/echo have gone out of sync and
this probably cannot be fixed any more.

Reported by: uqs (list of untouched files)
MFC after: 1 week

sh(1): Modernize the introduction a bit.

In particular, remove the text about ksh-like features, which are usually
taken for granted nowadays. The original Bourne shell is fading away and for
most users our /bin/sh is one of the most minimalistic they know.

sh: Fix some issues with aliases and case, by importing dash checkkwd code.

This moves the function of the noaliases variable into the checkkwd
variable. This way it is properly reset on errors and aliases can be used
normally in the commands for each case (the case labels recognize the
keyword esac but no aliases).

The new code is clearer as well.

Obtained from: dash

sh(1): Correct synopsis and make precise how $0 is set.

In particular, the extra argument to set $0 with -c was not documented.

MFC after: 1 week

sh: Reindent evaltree().

sh: Use iteration instead of recursion to evaluate semicolon lists.
This reduces CPU and memory usage when executing long lists (such
as long functions).

sh: Tweak some string constants to reduce code size.

* Reduce some needless differences.
* Shorten some error messages that should not happen.

sh: Reject function names ending in one of !%*+-=?@}~

These do something else in ksh: name=(...) is an array or compound variable
assignment and the others are extended patterns.

This is the last patch of the ones tested in the exp run.

Exp-run done by: pav (with some other sh(1) changes)

sh: Detect various additional errors in the parser.

Apart from detecting breakage earlier or at all, this also fixes a segfault
in the testsuite. The "handling" of the breakage left an invalid internal
representation in some cases.

Examples:
echo a; do echo b
echo `) echo a`
echo `date; do do do`

Exp-run done by: pav (with some other sh(1) changes)

sh: Error out on various specials/keywords in the wrong place in backticks.

Example:
echo `date)`

Exp-run done by: pav (with some other sh(1) changes)
Obtained from: NetBSD (Christos Zoulas, NetBSD PR 11317)

sh: Fix some issues with CTL* bytes and ${var#pat}.

subevalvar() incorrectly assumed that CTLESC bytes were present iff the
expansion was quoted. However, they are present iff various processing such
as word splitting is to be done later on.

Example:
v=@$e@$e@$e@
y="${v##*"$e"}"
echo "$y"
failed if $e contained the magic CTLESC byte.

Exp-run done by: pav (with some other sh(1) changes)

sh: Do IFS splitting on word in ${v+word} and ${v-word}.

The code is inspired by NetBSD sh somewhat, but different because we
preserve the old Almquist/Bourne/Korn ability to have an unquoted part in a
quoted ${v+word}. For example, "${v-"*"}" expands to $v as a single field if
v is set, but generates filenames otherwise.

Note that this is the only place where we split text literally from the
script (the similar ${v=word} assigns to v and then expands $v). The parser
must now add additional markers to allow the expansion code to know whether
arbitrary characters in substitutions are quoted.

Example:
for i in ${$+a b c}; do echo $i; done

Exp-run done by: pav (with some other sh(1) changes)

sh: Only accept a '}' inside ${v+-=?...} if double-quote state matches.
If double-quote state does not match, treat the '}' literally.

This ensures double-quote state remains the same before and after a
${v+-=?...} which helps with expand.c.

It makes things like
${foo+"\${bar}"}
which I have seen in the wild work as expected.

Exp-run done by: pav (with some other sh(1) changes)

sh: Make double-quotes quote a '}' inside ${v#...} and ${v%...}.

Exp-run done by: pav (with some other sh(1) changes)
PR: bin/57554

sh: Ignore double-quotes in arithmetic rather than treating them as quotes.

This provides similar behaviour, but allows a simpler parser.

This changes r206473.

Exp-run done by: pav (with some other sh(1) changes)

sh: Do not allow overriding a special builtin with a function.
This is a syntax error.

POSIX does not say explicitly whether defining a function with the same name
as a special builtin is allowed, but it does say that it is impossible to
call such a function.

A special builtin can still be overridden with an alias.

This commit is part of a set of changes that will ensure that when
something looks like a special builtin to the parser, it is one. (Not the
other way around, as it remains possible to call a special builtin named
by a variable or other substitution.)

Exp-run done by: pav (with some other sh(1) changes)

sh: Make sure defined functions can actually be called.

Add some conservative checks on function names:
- Disallow expansions or quoting characters; these can only be called via
strange control characters
- Disallow '/'; these functions cannot be called anyway, as exec.c assumes
they are pathnames
- Make the CTL* bytes work properly in function names.

These are syntax errors.

POSIX does not require us to support more than names (letters, digits and
underscores, not starting with a digit), but I do not want to restrict it
that much at this time.

Exp-run done by: pav (with some other sh(1) changes)

sh: Check whether dup2 was successful for >&FD and <&FD.

A failure (usually caused by FD not being open) is a redirection error.

Exp-run done by: pav (with some other sh(1) changes)

sh: Change ! within a pipeline to start a new pipeline instead.

This is how ksh93 treats ! within a pipeline and makes the ! in
a | ! b | c
negate the exit status of the pipeline, as if it were
a | { ! b | c; }

Side effect: something like
f() ! a
is now a syntax error, because a function definition takes a command,
not a pipeline.

Exp-run done by: pav (with some other sh(1) changes)

sh(1): Clarify subshells/processes for pipelines.

For multi-command pipelines,
1. all commands are direct children of the shell (unlike the original
Bourne shell)
2. all commands are executed in a subshell (unlike the real Korn shell)

MFC after: 1 week

sh: Use <stddef.h> rather than <sys/stddef.h>.

<sys/stddef.h> is only for the kernel and conflicts with <stddef.h>.

We only need to look as far as '..' to find 'test/'.

Do not assume in growstackstr() that a "precious" character will be
immediately written into the stack after the call. Instead let the caller
manage the "space left".

Previously, growstackstr()'s assumption causes problems with STACKSTRNUL()
where we want to be able to turn a stack into a C string, and later
pretend the NUL is not there.

This fixes a bug in STACKSTRNUL() (that grew the stack) where:
1. STADJUST() called after a STACKSTRNUL() results in an improper adjust.
This can be seen in ${var%pattern} and ${var%%pattern} evaluation.
2. Memory leak in STPUTC() called after a STACKSTRNUL().

Reviewed by: jilles

In the spirit of r90111, depend on c89 and remove the "STATIC" macro
and its usage.

If one wishes to set breakpoints of static the functions here, they
cannot be inlined.

Submitted by: jhb

Make DEBUG traces 64-bit clean:
- Use %t to print ptrdiff_t values.
- Cast a ptrdiff_t value explicitly to int for a field width specifier.

While here, sort includes.

Submitted by: Garrett Cooper

Suggest that DEBUG_FLAGS be used to enable extra debugging rather than
frobbing CFLAGS directly. DEBUG_FLAGS is something that can be specified
on the make command line without having to edit the Makefile directly.

Submitted by: Garrett Cooper

Consistently use "STATIC" for all functions in order to be able to set
breakpoints with in a debugger. And use naked "static" for variables.

Noticed by: bde

If DEBUG is 3 or greater, disable STATICization of functions.
Also correct the documented location of the trace file.

Allow one to regression test 'sh' changes without having to install
a potentially bad /bin/sh first.

sh: Add __dead2 to two functions that do not return.

Apart from helping static analyzers, this also appears to reduce the size of
the binary slightly.

sh: Fix exit status if return is used within a loop condition.

sh: Apply variable assignments left-to-right in bltinlookup().

Example:
HOME=foo HOME=bar cd

sh(1): Remove xrefs for expr(1) and getopt(1).

expr(1) should usually not be used as various forms of parameter expansion
and arithmetic expansion replicate most of its functionality in an easier
way.

getopt(1) should not be used at all in new code. Instead, getopts(1) or
entirely manual parsing should be used.

MFC after: 1 week

sh: Fix 'read' if all chars before the first IFS char are backslash-escaped.

Backslash-escaped characters did not set the flag for a non-IFS character.

MFC after: 2 weeks

sh: Improve comments in expand.c.

sh: Get rid of some magic numbers.

MFC after: 1 week

sh: Do not use locale for determining if something is a name.

This makes it impossible to use locale-specific characters in variable
names.

Names containing locale-specific characters make scripts only work with the
correct locale setting. Also, they did not even work in many practical cases
because multibyte character sets such as utf-8 are not supported.

This also avoids weirdness if LC_CTYPE is changed in the middle of a script.

sh: Remove remnants of '!!' to negate pattern.

This Almquist extension was disabled long ago.

In pathname generation, components starting with '!!' were treated as
containing wildcards, causing unnecessary readdir (which could fail, causing
pathname generation to fail while it should not).

sh(1): Add a brief summary of arithmetic expressions.

sh: Fix break/continue/return sometimes not skipping the rest of dot script.

In our implementation and most others, a break or continue in a dot script
can break or continue a loop outside the dot script. This should cause all
further commands in the dot script to be skipped. However, cmdloop() did not
know about this and continued to parse and execute commands from the dot
script.

As described in the man page, a return in a dot script in a function returns
from the function, not only from the dot script. There was a similar issue
as with break and continue. In various other shells, the return appears to
return from the dot script, but POSIX seems not very clear about this.

sh: Add a forgotten const.

sh: Fix shadowing of sigset.

sh: Fix heap-based buffer overflow in pathname generation.

The buffer for generated pathnames could be too small in some cases. It
happened to be always at least PATH_MAX long, so there was never an overflow
if the resulting pathnames would be usable.

This bug may be abused if a script subjects input from an untrusted source
to pathname generation, which a bad idea anyhow. Most shell scripts do not
work on untrusted data. secteam@ says no advisory is necessary.

PR: bin/148733
Reported by: Changming Sun snnn119 at gmail com
MFC after: 10 days

Remove unnecessary duplicate letters in mksyntax.c,
the table elements would just be overwritten twice.

sh: Return 0 from eval if no command was given.

This makes a difference if there is a command substitution.

To make this work, evalstring() has been changed to set exitstatus to 0 if
no command was executed (the string contained only whitespace).

Example:
eval $(false); echo $?
should print 0.

sh: Do not enter consecutive duplicates into the history.

This simply sets a flag in libedit. It has a shortcoming in that it does not
apply to multi-line commands.

Note that a configuration option for this is not going to happen, but always
having this seems better than not having it. NetBSD has done the same.

PR: bin/54683
Obtained from: NetBSD
MFC after: 1 month

sh: Fix crash due to uninitialized here-document.

If an ; or & token was followed by an EOF token, pending here-documents were
left uninitialized. Execution would crash, either in the main shell process
for literal here-documents or in a child process for expanded
here-documents. In the latter case the problem is hard to detect apart from
the core dumps and log messages.

Side effect: slightly different retries on inputs where EOF is not
persistent.

Note that tools/regression/bin/sh/parser/heredoc6.0 still causes a similar
crash in a child process. The text passed to eval is malformed and should be
rejected.

sh: Allow a background command consisting solely of redirections.

Example:
</dev/null &

MFC after: 2 weeks

sh: There cannot be a TNOT in simplecmd(), remove checks.

simplecmd() only handles simple commands and function definitions, neither
of which involves the ! keyword. The initial token on entry to simplecmd()
is one of the following: TSEMI, TAND, TOR, TNL, TEOF, TWORD, TRP.

sh: Use $PWD instead of getcwd() for the \w and \W prompt expansions.

This ensures that the logical working directory (which may include
symlinks) is shown and is similar to the default behaviour of the pwd
builtin.

sh: Forget about terminated background processes sooner.

Unless $! has been referenced for a particular job or $! still contains that
job's pid, forget about it after it has terminated. If $! has been
referenced, remember the job until the wait builtin has reported its
completion (either with the pid as parameter or without parameters).

In interactive mode, jobs are forgotten after termination has been reported,
which happens before primary prompts and through the jobs builtin. Even
then, though, remember a job if $! has been referenced.

This is similar to what is suggested by POSIX and should fix most memory
leaks (which also tend to cause sh to use more CPU time) with long running
scripts that start background jobs.

Caveats:
* Repeatedly referencing $! without ever doing 'wait', like
while :; do foo & echo started foo: $!; sleep 60; done
will still use a lot of memory and CPU time in the long run.
* The jobs and jobid builtins do not cause a job to be remembered for longer
like expanding $! does.

PR: bin/55346

sh: Fix compilation with -DNO_HISTORY.

The LINENO code uses snprintf() and relied on "myhistedit.h" to pull in the
necessary <stdio.h>.

Compiling with -DNO_HISTORY disables all editing and history support and
allows linking without -ledit -ltermcap. This may be useful for embedded
systems.

MFC after: 2 weeks

sh: Add filename completion.

This uses the new libedit completion function with quoting support.

Unlike NetBSD, there is no 'set +o tabcomplete' option to disable
completion. I do not see any reason for such a special treatment, as
completion is rather useful and it is possible to do
bind ^I ed-insert
to disable completion and insert a tab character instead.

Submitted by: Guy Yur

sh: Pass through SIGINT from a child if interactive and job control
is enabled.

This already worked if without job control.

In either case, this depends on it that a process that terminates due to
SIGINT exits on it (so not with status 1, or worse, 0).

Example:
sleep 5; echo continued
This does not print "continued" any more if sleep is aborted via ctrl+c.

MFC after: 1 month

sh: Pass TERM changes to libedit.

I have changed the patch slightly to ignore TERM changes in subshells.

PR: bin/146916
Submitted by: Guy Yur
Obtained from: NetBSD

sh: Fix a crash if a heredoc was not properly ended and parsing continued.

Example (in interactive mode):
cat <<EOF && )
The next command typed caused sh to segfault, because the state for the here
document was not reset.

Like parser_temp, this uses the fact that the parser is not re-entered.

sh: Change interaction of command substitution and here documents.

If a command substitution contains a newline token, this no longer starts
here documents of outer commands. This way, we follow POSIX's idea of the
command substitution being a separate script more closely. It also matches
other shells better and is consistent with newline characters in quotes not
starting here documents.

The extension tested in parser/heredoc3.0 ($(cat <<EOF)\ntext\nEOF\n)
continues to be supported.

In particular, this change allows things like
cat <<EOF && echo `pwd`
(a `` command substitution after a here document)
which formerly silently used an empty file as the here document, because the
EOF of the inner command "pwd" also forced an empty here document.

sh: Recognize "--" in . and exec.

Although "--" historically has not been required to be recognized for
certain special builtins that do not take options in POSIX, some other
implementations recognize options for them, requiring scripts to use "--" or
avoid operands starting with "-".

Operands starting with "-" can be avoided with eval by prepending a space,
and cannot occur with break, continue, exit, return and shift as they only
take numbers, nor with times as it does not take operands. With . and exec,
avoiding "-" is not so easy as it may require reimplementing the PATH
search; therefore the current proposal for POSIX is to require recognition
of "--" for them.

We continue to accept other strings starting with "-" as operands to . and
exec, and also "--" if it is alone to . (which would otherwise be invalid
anyway).

sh(1): Rework documentation of shell variables.

* Move the "environment variables" that do not need exporting to be
effective or that are set by the shell without exporting to a new section
"Special Variables".
* Add special variables LINENO and PPID.
* Add environment variables LANG, LC_* and PWD; also describe ENV under
environment variables.

sh(1): Improve wording of 'Special Parameters' section.

sh: Reap any zombies before forking for a background command.

This prevents accumulating huge amounts of zombies if a script executes
many background commands but no external commands or subshells.

Note that zombies will not be reaped during long calculations (within
the shell process) or read builtins, but those actions do not create
more zombies.

The terminated background commands will also still be remembered by the
shell.

PR: bin/55346

sh: Fix pathname expansion with quoted slashes like *\/.

These are git commits 36f0fa8fcbc8c7b2b194addd29100fb40e73e4e9 and
d6d06ff5c2ea0fa44becc5ef4340e5f2f15073e4 in dash.

Because this is the first code I'm importing from dash to expand.c, add the
Herbert Xu copyright notice which is in dash's expand.c.

When pathname expanding *\/, the CTLESC representing the quoted state was
erroneously taken as part of the * pathname component. This CTLESC was then
seen by the pattern matching code as escaping the '\0' terminating the
string.

The code is slightly different because dash converts the CTLESC characters
to backslashes and removes all the other CTL* characters to allow
substituting glob(3).

The effect of the bug was also slightly different from dash (where nothing
matched at all). Because a CTLESC can escape a '\0' in some way, whether
files were included despite the bug depended on memory that should not be
read. In particular, on many machines /*\/ expanded to a strict subset of
what /*/ expanded to.

Example:
echo /*"/null"

This should print /dev/null, not /*/null.

PR: bin/146378
Obtained from: dash

sh(1): Fix "reserved word" vs "keyword" inconsistency.
Use "keyword" everywhere, like the output of the 'type' builtin, and only
mention "reserved word" once to say it is the same thing.

sh: Have only one copy of _PATH_STDPATH in the binary.

sh: Apply locale vars on builtins, recognize LC_MESSAGES as a locale var.

This allows doing things like LC_ALL=C some_builtin to run a builtin under a
different locale, just like is possible with external programs. The
immediate reason is that this allows making printf(1) a builtin without
breaking things like LC_NUMERIC=C printf '%f\n' 1.2

This change also affects special builtins, as even though the assignment is
persistent, the export is only to the builtin (unless the variable was
already exported).

Note: for this to work for builtins that also exist as external programs
such as /bin/test, the setlocale() call must be under #ifndef SHELL. The
shell will do the setlocale() calls which may not agree with the environment
variables.

sh: Use stalloc for arith variable names.

This is simpler than the custom memory tracker I added earlier, and is also
needed by the dash arith code I plan to import.

sh: On startup of the shell, use PWD from the environment if it is valid.
Unset PWD if it is incorrect and no value for it can be determined.
This preserves the logical current directory across shell invocations.

Example (assuming /home is a symlink):
$ cd
$ pwd
/home/foo
$ sh
$ pwd
/home/foo

Formerly the second pwd would show the physical path (symlinks resolved).

sh: Partially revert r206146, allowing double-quotes in arithmetic.

These do pretty much nothing (except that parentheses are ignored), but
people seem to use them and allowing them does not hurt much.

Single-quotes seem not to be used and cause silently different behaviour
with ksh93 character constants.

sh: Automatically enable -o emacs in interactive shells with terminals.

This makes sh a bit more friendly in single user mode, make buildenv, chroot
and the like, and matches other shells.

The -o emacs can be overridden on the command line or in the ENV file.

sh: Document the expansion changes in the man page.

Note that the following sentence
> Enclosing the full parameter expansion string in double-quotes does not
> cause the following four varieties of pattern characters to be quoted,
> whereas quoting characters within the braces has this effect.
is now true, but used to be incorrect.

sh: Do tilde expansion in substitutions.

This applies to word in ${v-word}, ${v+word}, ${v=word}, ${v?word} (which
inherits quoting from the outside) and in ${v%word}, ${v%%word}, ${v#word},
${v##word} (which does not inherit any quoting).

In all cases tilde expansion is only attempted at the start of word, even if
word contains spaces. This agrees with POSIX and other shells.

This is the last part of the patch tested in the exp-run.

Exp-run done by: erwin (with some other sh(1) changes)

sh: Allow quoting pattern match characters in ${v%pat} and ${v#pat}.

Note that this depends on r206145 for allowing pattern match characters to
have their special meaning inside a double-quoted expansion like "${v%pat}".

PR: bin/117748
Exp-run done by: erwin (with some other sh(1) changes)

sh: Remove special handling for ' and " in arithmetic.
They will be treated like normal characters, resulting in a runtime
arithmetic expression error.

Exp-run done by: erwin (with some other sh(1) changes)

sh: Fix various things about expansions:
* remove the backslash from \} inside double quotes inside +-=?
substitutions, e.g. "${$+\}a}"
* maintain separate double-quote state for ${v#...} and ${v%...};
single and double quotes are special inside, even in a double-quoted
string or here document
* keep track of correct order of substitutions and arithmetic

This is different from dash's approach, which does not track individual
double quotes in the parser, trying to fix this up during expansion.
This treats single quotes inside "${v#...}" incorrectly, however.

This is similar to NetBSD's approach (as submitted in PR bin/57554), but
recognizes the difference between +-=? and #% substitutions hinted at in
POSIX and is more refined for arithmetic expansion and here documents.

PR: bin/57554
Exp-run done by: erwin (with some other sh(1) changes)

sh: Treat unexpected newlines in substitutions as a syntax error.

The old approach was wrong because PS2 was not used and seems unlikely to
parse extensions (ksh93's ${ COMMAND} may well fail to parse).

Exp-run done by: erwin (with some other sh(1) changes)

sh: Do not abort on a redirection error on a compound command.

Redirection errors on subshells already did not abort the shell because
the redirection is executed in the subshell.

Other shells seem to agree that these redirection errors should not abort
the shell.

Also ensure that the redirections will be cleaned up properly in cases like
command eval '{ shift x; } 2>/dev/null'

Example:
{ echo bad; } </var/empty/x; echo good

sh: Do not abort on a redirection error if there is no command word.

Although simple commands without a command word (only assignments and/or
redirections) are much like special builtins, POSIX and most shells seem to
agree that redirection errors should not abort the shell in this case. Of
course, the assignments persist and assignment errors are fatal.

To get the old behaviour portably, use the ':' special builtin.
To get the new behaviour portably, given that there are no assignments, use
the 'true' regular builtin.

sh: Fix longjmp clobber warnings in parser.c.

Make parsebackq a function instead of an emulated nested function.
This puts the setjmp usage in a smaller function where it is easier to avoid
bad optimizations.

sh: Make sure to popredir() even if a function caused an error.

sh: Make sure to popredir() even if a special builtin caused an error.

sh: Improve the command builtin:
* avoid unnecessary fork
* allow executing builtins via command
* executing a special builtin via command removes its special properties

Obtained from: NetBSD (parts)

Fix expansion of \W in prompt strings when the working directory is "/".
The prompt string was truncated after \W when the working directory was "/".

PR: bin/89410
Submitted by: Dr Balwinder Singh Dheeman
MFC after: 1 week

sh: Do not stat() $MAIL/$MAILPATH in non-interactive shells.

These may be NFS mounted, and we should not touch them unless we are going
to do something useful with the information.

sh: Send the "not found" message for builtin <cmd> to redirected fd 2.

sh: Fix some bugs with backquoted builtins:
- correctly handle error output in $(builtin 2>&1), clarify out1/out2 vs
output/errout in the code
- treat all builtins as regular builtins so errors do not abort the shell
and variable assignments do not persist
- respect the caller's INTOFF

Some bugs still exist:
- expansion errors may still abort the shell
- some side effects of expansions and builtins persist

sh(1): document ulimit -w (swapuse rlimit).

MFC after: 1 week

sh(1): Correct two places where "$@" lacked necessary quotes.

MFC after: 1 week

sh: Use PATH= assignment in type.

Example:
PATH=/var/empty; PATH=/bin type ls

sh: Allow command -pv and command -pV (lookup using _PATH_STDPATH).

sh: Ensure funcnest is decremented if there was an error in the function.

This will be important when things like 'command eval f' will be possible.
Currently, the funcnest = 0 assignment in RESET (called when returning to
the top level after an error in interactive mode) is really sufficient.

Fix memory leak when parsing backticks (``).

sh: arith: Return only 0 and 1 from && and ||.

This agrees with C, POSIX and other shells.

sh: Change varinit to use const better.

sh: Various warning fixes (from WARNS=6 NO_WERROR=1):
- const
- initializations to silence -Wuninitialized (it was safe anyway)
- remove nested extern declarations
- rename "index" locals to "idx"

Remove declaration of function that no longer exists.

sh: Do not run callers' exception handlers in subshells.

Reset the exception handler in the child to main's.

This avoids inappropriate double cleanups or shell duplication when the
exception is caught, such as 'fc' and future 'command eval' and 'command .'.

sh: Do not consider a tilde-prefix with expansions in it.

That is, do not do tilde expansion if any of the CTL* bytes (\201-\210), not
only CTLESC and CTLQUOTEMARK, are encountered. Such an expansion would look
up a user name with sh's internal representation.

The parser does not currently distinguish between backslashed and
unbackslashed \201-\210, so tilde expansion of user names with these bytes
in them is not so easy to fix.

sh: Add some __dead2 to indicate functions that do not return.

sh: Constify various strings.

Most of this is adding const keywords, but setvar() in var.c had to be
changed somewhat more.

sh: Remove setting variables from dotcmd/exportcmd.

It is already done by evalcommand(), unless special-ness has been removed,
in which case variable assignments should not persist. (These are currently
always special builtins, but this will change later: command builtin,
command substitution.)

This also fixes a memory leak when calling . with variable assignments.

Example:
valgrind --leak-check=full sh -c 'x=1 . /dev/null; x=2'

Fix some cases where file descriptors from redirections leak to programs.

- Redirecting fds that were not open before kept two copies of the
redirected file.
sh -c '{ :; } 7>/dev/null; fstat -p $$; true'
(both fd 7 and 10 remained open)
- File descriptors used to restore things after redirection were not
set close-on-exec, instead they were explicitly closed before executing
a program normally and before executing a shell procedure. The latter
must remain but the former is replaced by close-on-exec.
sh -c 'exec 7</; { exec fstat -p $$; } 7>/dev/null; true'
(fd 10 remained open)

The examples above are simpler than the testsuite because I do not want to
use fstat or procstat in the testsuite.

Fix various things about SIGINT handling:
* exception handlers are now run with interrupts disabled, which avoids
many race conditions
* fix some cases where SIGINT only aborts one command and continues the
script, in particular if a SIGINT causes an EINTR error which trumped the
interrupt.

Example:
sh -c 'echo < /some/fifo; echo This should not be printed'
The fifo should not have writers. When pressing ctrl+c to abort the open,
the shell used to continue with the next command.

Example:
sh -c '/bin/echo < /some/fifo; echo This should not be printed'
Similar. Note, however, that this particular case did not and does not work
in interactive mode with job control enabled.

sh: Ensure the same command input file is on top after executing a builtin.

This avoids weirdness when 'fc -e vi' or the like is done and there is a
syntax error in the file. Formerly an interactive shell tried to execute
stuff after the syntax error and exited.

This should also avoid similar issues with 'command eval' and 'command .'
when 'command' is implemented properly as in NetBSD sh.

Special builtins did not have this problem since errors in them cause the
shell to exit or to reset various state such as the current command input
file.

trap: do not consider a bad signal name a fatal error.
POSIX explicitly prescribes this.
Continue processing any other signals and return status 1.

Handle current work directories of arbitrary length. The argument to cd
continues to be limited by PATH_MAX (1024).

Obtained from: NetBSD
PR: 104456

sh: Some changes to stderr flushing:
* increase buffer size from 100 to 256 bytes
* remove implied flush from out2str(), in particular this avoids unnecessary
flushing in the middle of a -x tracing line
* rename dprintf() to out2fmt_flush(), make it flush out2 and use this
function in various places where flushing is desired after an error
message

sh: Allow a newline before "in" in a for command, as required by POSIX.

sh: Use sigaction instead of signal/siginterrupt combination.

sh: Fix memory leak when using a variable in arithmetic like $((x)).

MFC after: 3 weeks

sh: Exempt $@ and $* from set -u

This seems more useful and will likely be in the next POSIX standard.

Also document more precisely in the man page what set -u does (note that
$@, $* and $! are the only special parameters that can ever be unset, all
the others are always set, although they may be empty).

sh: Show more information about syntax errors in command substitution:
the line number where the command substitution started.
This applies to both the $() and `` forms but is most useful for ``
because the other line number is relative to the enclosed text there.
(For older versions, -v can be used as a workaround.)

Clarify quoting of word in ${v=word} in sh(1).

sh: Send the "xyz: not found" message to redirected fd 2.
This also fixes that trying to execute a non-regular file with a command
name without '/' returns 127 instead of 126.
The fix is rather simplistic: treat CMDUNKNOWN as if the command were found
as an external program. The resulting fork is a bit wasteful but executing
unknown commands should not be very frequent.

PR: bin/137659

sh: Disallow mismatched quotes in backticks (`...`).

Due to the amount of code removed by this, it seems that allowing unmatched
quotes was a deliberate imitation of System V sh and real ksh. Most other
shells do not allow unmatched quotes (e.g. bash, zsh, pdksh, NetBSD /bin/sh,
dash).

PR: bin/137657

Mention that NUL characters are not allowed in sh(1) input.

I do not consider this a bug because POSIX permits it and argument strings
and environment variables cannot contain '\0' anyway.

PR: bin/25542
MFC after: 2 weeks

sh: Fix crash with empty functions (f() { }) introduced in r196483

Empty pairs of braces are represented by a NULL node pointer, just like
empty lines at the top level.

Support for empty pairs of braces may be removed later. They make the code
more complex, have inconsistent behaviour (may or may not change $?), are
not specified by POSIX and are not allowed by some other shells like bash,
dash and ksh93.

Reported by: kan

sh: Fix crash when undefining or redefining a currently executing function.

Add a reference count to function definitions.
Memory may leak if multiple SIGINTs arrive in interactive mode,
this will be fixed later by changing SIGINT handling.

PR: bin/137640

Fix some weirdnesses in the NetBSD IFS code,
in particular "$@"$ifschar if the final positional parameter is empty.
With the NetBSD code, adding the $ifschar removes a parameter.

PR: standards/79067
Approved by: ed (mentor) (implicit)

Improve IFS expansion using code from NetBSD.

We now pass the ifs.sh testsuite.

PR: standards/79067
Approved by: ed (mentor) (implicit)
Obtained from: NetBSD

Designate special builtins as such in command -V and type.
Also document various properties of special builtins that we implement.

Approved by: ed (mentor) (implicit)

Quote -x tracing output so it is unambiguous.

It is usually but not always suitable for re-input to the shell.

Approved by: ed (mentor) (implicit)

Do not fork for a subshell if it is the last thing this shell is doing
(EV_EXIT). The fork is still done as normal if any traps are active.

In many cases, the fork can be avoided even without this change by using {}
instead of (), but in practice many scripts use (), likely because the
syntax is simpler.

Example:
sh -c '(/bin/sleep 10)& sleep 1;ps -p $! -o comm='
Now prints "sleep" instead of "sh". $! is more useful this way.
Most shells (dash, bash, pdksh, ksh93, zsh) seem to print "sleep" for this.

Example:
sh -c '( ( ( (ps jT))))'
Now shows no waiting shell processes instead of four.
Most shells (dash, bash, pdksh, ksh93, zsh) seem to show zero or one.

PR: bin/74404
Approved by: ed (mentor) (implicit)

Usermode portion of the support for swap allocation accounting:
- update for getrlimit(2) manpage;
- support for setting RLIMIT_SWAP in login class;
- addition to the limits(1) and sh and csh limit-setting builtins;
- tuning(7) documentation on the sysctls controlling overcommit.

In collaboration with: pho
Reviewed by: alc
Approved by: re (kensmith)

sh: Improve handling of setjmp/longjmp volatile:
- remove ineffective and unnecessary (void) &var; [1]
- remove some unnecessary volatile keywords
- add a necessary volatile keyword
- save the old handler before doing something that could use the saved
value

Submitted by: Christoph Mallon [1]
Approved by: ed (mentor)

Fix race condition in noclobber option.

Formerly, it was possible for the file to be created between the check if it
existed and the open; the contents would then be lost.

Because this must use O_EXCL, noclobber > will not create a file through a
symlink anymore. This agrees with behaviour of other shells.

Approved by: ed (mentor) (implicit)

Fix some issues with quoted output and shorten it in some cases.

Output quoted suitable for re-input to the shell occurs in
various cases such as 'set', 'trap'.

Bugfix: *, ? and [ must be quoted (except sole [)
Bugfix: ~ and # must be quoted (really only sometimes, but keep it simple)
Bugfix: space, tab and newline must always be quoted
Shortening: other IFS characters do not need quoting
Bugfix: send to correct output file, not hard-coded stdout
Shortening: avoid unnecessary '' with \'

Approved by: ed (mentor)

Properly flush input after an error in backquotes in interactive mode.

For parsing an old-style backquote substitution (`...`),
a string "file" is used to store the contents of the
substitution (with the special backslash processing done).
If an error occurs, the shell cleans up all these files
(returning to the top level) and flush the top level
file. Erroneously, it first flushed the current file and
then cleaned up all extra files, so that the top level
file (i.e. the terminal) was not flushed.

Example (in interactive mode):
echo `for` echo This should not be printed

Also noticeable in (in interactive mode):
echo `(`
The old version prints an extraneous prompt.

Approved by: ed (mentor)

Avoid leaving unnecessary waiting shells in many forms of sh -c COMMAND.

This change only affects strings passed to -c, when the -s
option is not used.

The approach is to check if there may be additional data
in the string after parsing each command. If there is none,
use the EV_EXIT flag so that a fork may be omitted in
specific cases.

If there are empty lines after the command, the check will
not see the end and forks will not be omitted. The same
thing seems to happen in bash.

Example:
sh -c 'ps lT'
No longer shows a shell process waiting for ps to finish.

PR: bin/113860
Reviewed by: stefanf
Approved by: ed (mentor)

Don't skip forking for an external command if any traps are active.

Example:
sh -c '(trap "echo trapped" EXIT; sleep 3)'
now correctly prints "trapped".

With this check, it is no longer necessary to check for -T
explicitly in that case.

This is a useful bugfix by itself and also important because I plan to
skip forking more often.

PR: bin/113860 (part of)
PR: bin/74404 (part of)
Reviewed by: stefanf
Approved by: ed (mentor)

Mention the range for the exit status for the exit special builtin.

The exit status may exceed 255 in some cases (return); even though it seems
unwise to rely on this, it is also unwise to assume that $? is always
between 0 and 255.

This resolves bin/124748 by documenting that 'exit -1' is not valid.

PR: bin/124748
Approved by: ed (mentor)

use explicit 'unsigned int' instead of just the implicit-style 'unsigned' to make linting tools (e.g. FlexeLint) happy, too

align coding style with style(9) to avoid misunderstandings

correctly test for __GNUC__ macro (non-GCC compilers do not have it defined at all)

be more type correct and align local ckmalloc() with its underlying malloc(3) by using a "size_t" instead of an "int" argument

sh: Make read's timeout (-t) apply to the entire line, not only the first
character.

This avoids using non-standard behaviour of the old (upto FreeBSD 7) TTY
layer: it reprocesses the input queue when switching to canonical mode. The
new TTY layer does not provide this functionality and so read -t worked
very poorly (first character is not echoed, cannot be backspaced but is
still read).

This also agrees with what most other shells with read -t do.

PR: bin/129566
Reviewed by: stefanf
Approved by: ed (mentor)

Fix the eval command in combination with set -e. Before this change the shell
would always terminate if eval returned with a non-zero exit status regardless
if the status was actually tested. Unfortunately a new file-scope variable
is needed, the alternative would only be to add a new parameter to all
built-ins.

PR: 134881

Parse 'cmd1 && ! cmd2 | cmd3' correctly, the bang should apply to the entire
pipeline cmd2 | cmd3 and not just cmd2.

PR: 130298
Submitted by: Jilles Tjoelker

Don't let trailing empty lines overwrite the result of the last command with 0.
This affects the built-ins eval, fc, and trap and also the string passed to sh
with the -c option.

Submitted by: Jilles Tjoelker

Fix the behaviour of the read built-in when IFS is unset.

Obtained from: NetBSD

Improve the IFS handling of the read built-in.

Obtained from: NetBSD
Submitted by: Jilles Tjoelker

- Apply the r190270 changes to printing of single aliases too.
- Sort the aliases before printing them.

Make the output of the alias built-in POSIX-compliant: Drop the leading 'alias'
and suppress printing the trailing space which is added for internal purposes.

Don't disable CR-to-NL translation when waiting for data to arrive.

A difference between the old and the new TTY layer is that the new
implementation does not perform any post-processing before returning
data back to userspace when calling read().

sh(1)'s read turns the TTY into a raw mode before calling select(). This
means that the first character will not receive any ICRNL processing.
Inherit this flag from the original terminal attributes.

Even though this issue is not present on RELENG_*, I'm MFCing it to make
sh(1) in jails behave better.

PR: bin/129566
MFC after: 2 weeks

Report error messages of the builtins 'type' and 'command -V' to stderr instead
of stdout.

Noticed by: Zajcev Evgeny

Fix $? at the first command of a function. The previous exit status was saved
twice and thus lost.

Document the ulimit -p option in the sh(1) manual page.

When I imported the MPSAFE TTY code, I added the -p flag to sh(1)'s
ulimit, but I forgot to document it in the appropriate manual page.

Requested by: stefanf

Fix a bug in r177497 which caused the getopts state to be reset when 'set'
was used to set a shell option (and not to change the positional parameters).

Submitted by: Martin Kammerhofer

Integrate the new MPSAFE TTY layer to the FreeBSD operating system.

The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.

If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).

The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan

Mark functions as __dead2 in order to help the LLVM static checker
understand which code paths aren't possible.

This commit eliminates 117 false positive bug reports of the form
"allocate memory; error out if pointer is NULL; use pointer".

Pass the correct flags to expandarg() for NFROMFD and NTOFD. This fixes a
segmentation fault when the argument expands to an empty string.

Reported by: simon
MFC after: 3 weeks

use 'const' for the parameters of the two static functions unalias() and hashalias()

remove an unnecessary include

Fix checking if a variable name is LINENO. As STPUTC changes the pointer if it
needs to enlarge the buffer, we must not keep a pointer to the beginning.

PR: ports/123879

Expand $LINENO to the current line number. This is required by SUSv3's "User
Portability Utilities" option.

Often configure scripts generated by the autotools test if $LINENO works and
refuse to use /bin/sh if not.

Package test run by: pav

Sigh, when reapplying the patch to HEAD, I somehow forgot to commit this file.

Reported by: Jaakko Heinonen

- Fix bugs where the value of arithmetic expansion$((...)) was trucated
to type int.
- Change the type used for arithmetic expansion to intmax_t (ie. 64 bit on all
currently supported FreeBSD architectures). SUSv3 requires at least type
long but allows for larger types. Other shells (eg. bash, zsh, NetBSD's sh)
do that too.

PR: 122659
Submitted by: Jaakko Heinonen (minor modifications by me)

Reset the internal state used for the 'getopts' built-in when 'shift' or 'set'
are used to modify the arguments. Not doing so caused random memory reads or
null pointer dereferences when 'getopts' was called again later (SUSv3 says
getopts produces unspecified results in this case).

PR: 48318

Split updatepwd() into two smaller functions. The first one, findpwd(),
computes the new path and the second one, updatepwd(), updates the variables
PWD, OLDPWD and the path used for the pwd builtin according to the new
directory. For a logical directory change, chdir() is now called between
those two functions, no longer causing wrong values to be stored in PWD etc. if
it fails.

PR: 64990, 101316, 120571

Fix "warning: comparison is always false due to limited range of data type"
on platforms with unsigned chars. The comparison in question is there to
determine whether chars are unsigned or not and is based on comparing a
char, initialized to -1, for less than 0. Change the comparison to check
for geater than 0 instead...

Revise the markup.

Reduce the WARNS level to avoid a compiler warning about a variable
possibly being clobbered by a longjmp or a fork with gcc4.

The exit status of a case statement where none of the patterns is matched
is supposed to be 0, not the status of the previous command.

Reported by: Eygene Ryabinkin
PR: 116559
Approved by: re (gnn)

Take care that the input to setenv() may actually be a pointer straight
from environ; make a copy before manipulating it and passing it to
setenv().

Approved by: wes
Approved by: re (kensmith)

Significantly reduce the memory leak as noted in BUGS section for
setenv(3) by tracking the size of the memory allocated instead of using
strlen() on the current value.

Convert all calls to POSIX from historic BSD API:
- unsetenv returns an int.
- putenv takes a char * instead of const char *.
- putenv no longer makes a copy of the input string.
- errno is set appropriately for POSIX. Exceptions involve bad environ
variable and internal initialization code. These both set errno to
EFAULT.

Several patches to base utilities to handle the POSIX changes from
Andrey Chernov's previous commit. A few I re-wrote to use setenv()
instead of putenv().

New regression module for tools/regression/environ to test these
functions. It also can be used to test the performance.

Bump __FreeBSD_version to 700050 due to API change.

PR: kern/99826
Approved by: wes
Approved by: re (kensmith)

Back out all POSIXified *env() changes.

Not because I admit they are technically wrong and not because of bug
reports (I receive nothing). But because I surprisingly meets so
strong opposition and resistance so lost any desire to continue that.

Anyone who interested in POSIX can dig out what changes and how
through cvs diffs.

Simplify previous fix and disallow VTEXTFIXED direct pass for putenv() too,
just use savestr()

Put some safeguards:
1) Under POSIX unsetenv("foo=bar") is explicit error and not equal
to unsetenv("foo")
2) Prepare for upcomig POSIXed putenv() rewrite: make putenv() calls
portable and conforming to standard.

Use eaccess() instead of access() for the type builtin, like we do for the
test builtin.

Submitted by: Martin Kammerhofer

Return an error status (127) from the builtins 'type' and 'command' (with
either -v or -V) if a file with a slash in the name doesn't exist (if there is
no slash we already did that).

Additionally, suppress the error message for command -v for files with a slash.

PR: 107674
Submitted by: Martin Kammerhofer

Fix expanding of quoted positional parameters in case patterns.

Obtained from: NetBSD (expand.c 1.58 and 1.59)
Submitted by: Paul Jarc
PR: 56147

When parsing an invalid parameter expansion (eg. ${} or ${foo@bar}) do not
issue a syntax error immediately but save the information that it is erroneous
for later when the parameter expansion is actually done. This means eg. "false
&& ${}" will not generate an error which seems to be required by POSIX.
Include the invalid parameter expansion in the error message (sometimes
abbreviated with ... because recovering it would require a lot of code).

PR: 105078
Submitted by: emaste

Add the POSIX option -p to the jobs builtin command. It prints the PID of the
process leader for each job. Now the last specified option for the output
format (-l, -p or -s) wins, previously -s trumped -l.

PR: 99926
Submitted by: Ed Schouten and novel (patches modified by me)

Markup fixes.

Commit the results of the typo hunt by Darren Pilgrim.
This change affects documentation and comments only,
no real code involved.

PR: misc/101245
Submitted by: Darren Pilgrim <darren pilgrim bitfreak org>
Tested by: md5(1)
MFC after: 1 week

Do not forget to increment the input line counter
when reading a word spanning multiple lines.

PR: bin/101094
MFC after: 5 days

Tell more of the sh(1) history.
Acknowledge Kenneth Almquist's contribution in AUTHORS.

MFC after: 5 days

Make it easier to find that we have test(1) built-in in sh(1).

MFC after: 3 days

Document the fact that 'true' and 'false' are among sh(1) built-in commands.

MFC after: 3 days

Merge NetBSD's revision 1.86: Don't crash on "<cmd> | { }".

Implement the PS4 variable which is defined by the POSIX User Portability
Utilities option. Its value is printed at the beginning of the line if tracing
(-x) is active. PS4 defaults to the string "+ " which is compatible with the
old behaviour to always print "+ ".

We still need to expand variables in PS1, PS2 and PS4.

PR: 46441 (part of)
Submitted by: schweikh
Obtained from: NetBSD

Don't strip a leading ./ from the path for the cd builtin to avoid interpreting
.//dir as /dir. Rather strip it only for the purpose of checking if the
directory path should be printed.

PR: 88813
Submitted by: Josh Elsasser
Patch from: NetBSD (cd.c rev 1.38)
MFC after: 2 weeks

POSIX demands that set's output (when invoked without arguments) should be
sorted. Sort the variables before printing.

PR: 96415

Check the buffer size when copying the line returned by el_gets() into our
own buffer. Interactively typing in long lines (>1023 characters)
previously overflowed the buffer. Unlike the NetBSD people I don't see the
need to subtract 8 from BUFSIZ, so I just used BUFSIZ-1.

Obtained from: NetBSD
PR: 91110

Whitespace nits.

Correct assorted grammos and typos.

Output something reasonable for regular and expanded here-documents.
I would have chosen the EOF markers, but they are no longer available
AFAICS, so output "<<HERE" and "<<XHERE" instead.
(NOTE: These changes only affect DEBUG output.)

Implement some of the differences between special built-ins and other builtins
demanded by POSIX.
- A redirection error is only fatal (meaning the execution of a shell script is
terminated) for special built-ins. Previously it was fatal for all shell
builtins, causing problems like the one reported in PR 88845.
- Variable assignments remain in effect for special built-ins.
- Option or operand errors are only fatal for special built-ins.
This change also makes errors from 'fc' non-fatal (I could not find any reasons
for this behaviour).

Somewhat independently from the above down-grade the error handling in the
shift built-in if the operand is bigger than $# from an error() call (which is
now fatal) to a return 1. I'm not sure if this should be considered a POSIX
"operand error", however this change is needed for now as we trigger that error
while building libncurses. Comparing with other shells, zsh does the same as
our sh before this change (write a diagnostic, return 1), bash behaves as our
sh after this commit (no diagnostic, return 1) and ksh93 and NetBSD's sh treat
it as a fatal error.

Issue an error when . (dot) is invoked without a filename. The synopsis
is just ". file" according to POSIX, however many other shells allow
arguments to be passed after the file. For compatibility (we even use that
feature in buildworld) additional arguments are not considered to be an
error, even though this shell does not do anything with the arguments at all.

Use -s to flag POSIX's "special built-in" utilities in builtins.def. Add a
new member to struct builtincmd and set it to 1 if -s was specified. This
is done because there are cases where special builtins must be treated
differently from other builtins.

Obtained from: NetBSD (builtins.def part)

Initialize PWD early on (don't expect it to be inherited from the
environment or set it only when changing directories with cd).

PR: standards/92640

s/staticly/statically/g

s/varable/variable/; s/tored/stored/

Remove some white space at EOL.

Document that '#' starts a comment.

PR: 85103
Submitted by: garys
Obtained from: pdksh manual
Patch from: Daniel Gerzo (with changes by me)

o Now when SIG_IGN signal action for SIGCHLD reap zombies
automatically it is possible wait4(2) returns -1 and sets
errno = ECHILD if there were forked children. A user can
set such signal handler e.g. via ``trap "" 20'', see a PR
for the test case. Deal with this case and mark a job as
JOBDONE.

PR: bin/90334
Submitted by: bde
MFC after: 4 weeks

- Document trap's -l option and the behaviour of a missing action or a single
dash.
- Discourage the omission of the action.

PR: 70985 [1]
Submitted by: Martin Kammerhofer

Print empty quotes ('') when an empty string is passed to outqstr().
This makes a difference for the trap builtin, where after "trap '' 0" we
printed "trap -- quit". This is wrong, because an empty action means to reset
the action to the default. A side effect of this commit is that empty
variables are now printed as "variable=''" instead of just "variable=".

Correctly quote the output when showing the installed trap actions.

PR: 74043
Submitted by: Jilles Tjoelker

Clarify that the echo builtin takes an arbitrary number of strings.
Mention that spaces are printed between the strings.

Sort.

Remove a few commented out builtins from the original ash. The files
implementing them were never part of FreeBSD.

Add the times builtin. It reports the user and system time for the shell
itself and its children. Instead of calling times() (as implied by POSIX) this
implementation directly calls getrusage() to get the times because this is more
convenient.

-mdoc sweep.

Add `local' and `return' to the list of built-ins.

Submitted by: garys
Approved by: trhodes (mentor)

Include disabled options in the output of 'set +o'. POSIX says the output of
set +o can be used to reload previous settings, for this to work disabled
options must be printed as well or otherwise options that were set in the mean
time won't be turned off.

To avoid an excessively long output line I formatted the output to print only
six options per line.

Submitted by: Jilles Tjoelker
PR: 73500

Document command -v and -V.

Glanced at by: simon

Document that read -t timeout returns 1 if the timeout elapses.

Add the POSIX options -v and -V to the 'command' builtin. Both describe the
type of their argument, if it is a shell function, an alias, a builtin, etc.
-V is more verbose than -v.

PR: 77259, 84539

Protect malloc, realloc and free calls with INT{ON,OFF} directly in chkalloc,
ckrealloc and ckfree (added), respectively. sh jumps out of the signal handler
using longjmp which is obviously a bad idea during malloc calls.

Note: I think there is still a small race here because volatile sig_atomic_t
only guarantees atomic reads and writes while we're doing increments and
decrements.

Protect a setmode call with INT{ON,OFF} as it calls malloc internally.

PR: 45478
Patch from: Nate Eldredge

Use the new name H_SETSIZE instead of the old H_EVENT to set the history
size.

PR: 86355

Elaborate on the behaviour of set -e.

Pass the EV_TESTED flag to evalloop() and evalfor(). This fixes unwanted
termination with set -e if a command fails in a loop body inside a function
with an explicitely tested exit status, eg

f() {
for i in 1 2 3; do
false
done
}
f || true

Briefly reviewed by: cracauer

Pass the EV_TESTED flag to the left operand of NSEMI nodes. This fixes
two cases of unwanted termination with set -e:

* if-commands containing several commands separated by semicolons, eg

if false; false; then [...]

* functions with an explicitely tested exit status that contain a failing
command which is not the last one, eg

f() {
false
false
}
f || true

PR: 77067, 85267
Briefly reviewed by: cracauer

Exit the shell if a pipeline that is not preceded by ! fails and set -e is
active. Use a separate flag to avoid adding another condition to the
if-statement at the end of evaltree().

Briefly reviewed by: cracauer

Split the export synopsis into two lines as -p cannot be mixed with variable
names.

- Provide a reasonable error message for `export -p var'.
- Use argv rather than argptr since getopt() is used here.

Fix the error message if the mask that is passed to umask -S contains
non-digits.

Various small code cleanups resulting from a code reviewing
and linting procedure:

1. Remove useless sub-expression:

- if (*start || (!ifsspc && start > string && (nulonly || 1))) {
+ if (*start || (!ifsspc && start > string)) {

The sub-expression "(nulonly || 1)" always evaluates to true and
according to CVS logs seems to be just a left-over from some
debugging and introduced by accident. Removing the sub-expression
doesn't change semantics and a code inspection showed that the
variable "nulonly" is also not necessary here in any way (and the
expression would require fixing instead of removing).

2. Remove dead code:

- if (backslash && c == '\\') {
- if (read(STDIN_FILENO, &c, 1) != 1) {
- status = 1;
- break;
- }
- STPUTC(c, p);
- } else if (ap[1] != NULL && strchr(ifs, c) != NULL) {
+ if (ap[1] != NULL && strchr(ifs, c) != NULL) {

Inspection of the control and data flow showed that variable
"backslash" is always false (0) when the "if"-expression is
evaluated, hence the whole block is effectively dead code.
Additionally, the skipping of characters after a backslash is already
performed correctly a few lines above, so this code is also not
needed at all. According to the CVS logs and the ASH 0.2 sources,
this code existed in this way already since its early days.

3. Cleanup Style:

- ! trap[signo][0] == '\0' &&
+ ! (trap[signo][0] == '\0') &&

The expression wants to ensure the trap is not assigned the empty
string. But the "!" operator has higher precedence than "==", so the
comparison should be put into parenthesis to form the intended way of
expression. Nevertheless the code was effectively not really broken
as both particular NUL comparisons are semantically equal, of course.
But the parenthesized version is a lot more intuitive.

4. Remove shadowing variable declaration:

- char *q;

The declaration of symbol "q" hides another identical declaration of
"q" in the same context. As the other "q" is already reused multiple
times and also can be reused again without negative side-effects,
just remove the shadowing declaration.

5. Just small cosmetics:

- if (ifsset() != 0)
+ if (ifsset())

The ifsset() macro is already coded by returning the boolean result
of a comparison operator, so no need to compare this boolean result
again against a numerical value. This also aligns the macros usage to
the remaining existing code.

Reviewed by: stefanf@

fix typo: ommitted -> omitted

Print pointers with %p rather than casting them to long.

Document that `in word ...' is optional in the for command.

Return 1 from the unalias builtin if _any_ removal fails, not just the last
one.

Remove extra getenv() declaration.

Document that unalias can be used to remove several alias names.

Wrap a line due to a new sentence.

Noticed by: simon
Approved by: trhodes (mentor)

o Discuss the ways to escape an alias.
o Fix the alias syntax lines.
o Refer to the Aliases subsection.

PR: docs/84914
Submitted by: garys
Approved by: trhodes (mentor)
MFC after: 3 days

Document umask's -S option.

Remove a hack for an ancient gdb.

Recent cleanups made it possible to bump WARNS to 3.

Put the comparison with PEOF into a new macro is_eof(). Don't use it if the
character comes from a string.

Declare echocmd() and testcmd().

Use assignment rather than comparison.

- Provide all initialisers for a struct event.
- Include init.h in the generated init.c.
- Generate prototypes and put the brace on the next line.

First declare the functions to pacify -Wmissing-prototypes.

Include missing headers.

Use prototypes in the MKINIT lines collected by mkinit.

Use prototypes in the generated builtins.{c,h} files.

cvs -d stefanf@ncvs.FreeBSD.org:/home/ncvs

El_parse's third parameter is now const-qualified, add a cast.

Fix a bug when shell expansion is done against dangling symlinks, by
converting the stat() call to a lstat() call, which will cover the
situation. One can exercise this bug by referring a dangling link with
something like */the-link.

Approved by: re (scottl)
Submitted by: Simon 'corecode' Schubert [corecode fs ei tum de]
Obtained from: NetBSD via DragonFlyBSD (NetBSD rev. 1.51 and DragonFly
rev. 1.6)
MFC After: 3 days

Sorted sections and fixed prompt (PS[12]) strings.

Approved by: re (blanket)

Put the description of the -c option in the right place, as
promised by the Argument List Processing section introduction.
What follows the option in the options list is its long name,
not its argument (as is the case for the -c option). Also
sort references in the SEE ALSO section.

Approved by: re (blanket)

A second attempt to adjust option-parsing on a shell command, for the
benefit of scripts start out as: #!/bin/sh -- # -*- perl -*-
With this fix in place, we can commit a change to kern/imgact_shell.c
so FreeBSD will process the `#!' line in shell-scripts in a more
standard fashion.

PR: 16393
Mentioned on: freebsd-arch

Various sh(1) enhancements:
- Move the description of the ``-c string'' option closer to the option itself.
- Add an ENVIRONMENT section (1)
- Add more .Xr cross references to the SEE ALSO section.

Obtained from: NetBSD (1)

Use ``.Pq Ql'' to quote single characters, instead of ``.Pq Li''.
This makes the resulting output more aesthetically pleasing in
text-only terminals:

Reviewed by: ru

Add a section describing the exit status of the shell.

Obtained from: NetBSD

Support \H, \h, \w, \W, \$ string expansion in the prompt.

Submitted by: mini

Change /bin/sh so *it* implements the processing needed for scripts to
work as expected when they have a "shebang line" of:

#!/bin/sh -- # -*- perl -*- -p

This specific line is recommended in some perl documentation, and I think
I've seen similar lines in documentation for ruby and python. Those
write-ups expect `sh' to ignore everything after the '--' if the first
thing after the '--' is a '#'. See chapter 19, "The Command-Line Interface"
in 3rd edition of "Programming Perl", for some discussion of why perl
recommends using this line in some circumstances.

The above line does work on solaris, irix and aix (as three data points),
and it used to work on FreeBSD by means of a similar patch to execve().
However, that change to execve() effected *all* shells (which caused
other problems), and that processing was recently removed.

PR: 16393 (the original request to fix the same issue)
Reviewed by: freebsd-current (looking at a slightly different patch)
MFC after: 1 week

/*- or .\"- or #- to begin license clauses.

Scheduled mdoc(7) sweep.

Correct typo.

o Add a missed "." .

Reviewed by: ru
MFC after: 3 weeks

o Terminate an endless loop sh -T goes into in dowait() around waitproc().

XXX from Tor: "The shell can also go into a similar loop if the child was
killed by signal 127, since the shell would believe the child to have
only stopped (WIFSTOPPED() macro returns nonzero value). Disallowing
signals 127 and 128 will fix that problem." See kern/19402 for details.

PR: bin/66242
Submitted by: tegge
Analysis and testcase by: demon
MFC after: 3 weeks

When listing the special $ variables, ($!, $#, etc) list them as $!
instead of just !, this allows one to more easily locate/understand
the section of the manpage in question.

Additional wording correction by: keramida
Reviewed by: keramida

Attempting to unset an undefined variable or function should not be
considered an error according to the Open Group Base Specification.

PR: standards/45738
Submitted by: Matthias Andree <matthias.andree@web.de>
MFC after: 3 days

Document missing multibyte character handling in utilities specified
by POSIX.

Deal with double whitespace.

Mechanically kill hard sentence breaks.

Include <stdio.h> for a sprintf() prototype.

Approved by: das (mentor)

Document the "return" built-in better: it will exit . (sources) and
the top-level shell instance, too.

Remove clause 3 from the UCB licenses.

OK'ed by: imp, core

Install /bin/sh safely. This allows a shell script to be used
to strip binaries by specifying it in the STRIPBIN environment
variable honoured by install(1).

MFC after: 3 days

style.Makefile:
Use WARNS?= instead of WARNS=

style(9): wrap at 80 columns.

Handle proper formatting and a buffer overrun when running an old sh on
a system that has sys_nsig > NSIG (i.e. when libc is upgraded.)

Submitted by: Matt Dillon
Reviewed by: bde

Fixed style of DPADD and LDADD assignments as per style.Makefile(5).

Commit fix sent by Tor Egge <Tor.Egge@cvsup.no.freebsd.org>

Only use return value from system call if system call succeeded.

Tested with `make world` and some of my own scripts.

This should be MFCed soon. While /bin/sh is hard to test the fix is
obviously correct and can be assumed not to break something else
(famous last words...).

Use sys_nsig instead of NSIG for the length of the signal arrays. This
is important if we add new signals later. From DragonflyBSD:
jobs.c:1.4, trap.c:1.3.

Obtained from: DragonflyBSD

The PR diff I committed recently had one bug noticed by
Joe Marcus Clarke <marcus@FreeBSD.ORG>, subshells could lose a
non-zero exit status.

This commit is Joe's proposed patch. Thanks!

I verified that the problem Joe found is fixed and I ran a full world
with this patch.

I don't plan to ever commit language patches to /bin/sh again. It is
a minefield too big to navigate without a full-time committment, which
I am not willing to do on our /bin/sh.

Under normal circumstances I would recommend using NetBSD's sh which
has a lot of language fixes (like the ones what these patches were
about) but unfortunately they had implemented broken signal behaviour
for shellscript containing interactive programs. Similar issues apply
to pdksh which is OpenBSD's sh.

From my perspective bash2 is the only really working bourne sh out
there and that one is GPLed. Oh well.

Replace home-grown dup2() implementation with actual dup2() calls. This
should slightly reduce the number of system calls in critical portions of
the shell, and select a more efficient path through the fdalloc code.

Reviewed by: bde

Removed duplicate y.tab.h from SRCS and CLEANFILES.

o Spell 'diretories' correctly.

PR: misc/60730
Submitted by: Eugene Grosbein
MFC after: 3 days

PR 28852

sh -e behaviour was incorrect when && and || statements where used in
"if" clauses.

This is the patch submitted by MORI Kouji <mori@tri.asanuma.co.jp>.

It fixes the issue at hand, but sh fixes like this are super-hard to
verify that they don't break anything else. I ran some of my old test
cases and a few big GNU configure scripts that detected mistakes
before, with the previous sh, patched sh and bash. No differences in
behaviour found. MFC recommended after longer than usual time.

Compiles on i386 and sledge.

Do not assume there is only a space between #define and the macro name
when grepping for JOBS. The recent style cleanup replaced the space with
a tab and broke job control detection. Little edits, disastrous consequences.

Submitted by: Peter Edwards <pmedwards@eircom.net>
X-MFC when: in about 5 weeks with the other sh arithmetic fixes.

mdoc(7): Use the new feature of the .In macro.

Fix testing of arith_assign() value for $((a=15)).

Submitted by: Enache Adrian <enache@rdslink.ro>

#include <string.h> for prototypes for strcpy() and strlen().

Submitted by: Stefan Farfeleder

Style cleanup, mostly

Requested by: bde

Implement missing shell arithmetic operators in $(()) expansion
and variable recognition.

PR: standards/52972
Submitted by: Wartan Hachaturow <wart@tepkom.ru>
Reviewed by: tjr (improved on original patch)
Tested by: buildworld on CURRENT.
MFC after: 6 weeks

Remove collate_range_cmp() stabilization, it conflicts with ranges

Changes following CScout analysis:

- Removed dead declarations
- Made objects that should have been declared as static, static.

The changes use STATIC instead of static, following the existing
convention in the rest of the code.

Approved by: schweikh (mentor)
MFC after: 2 weeks

Instead of eating trailing newlines after inserting them into the
output buffer, don't insert them at all. This prevents a buffer
*underrun* when the substitution consists completely of newlines
(e.g. `echo`) and the byte before the source buffer to which p
points is a '\n', in which case more characters would be removed
from the output buffer than were inserted.

This fixes certain port builds on sparc64.

Approved by: re (scottl)
Reviewed by: des, tjr

mdoc(7) police: A better version of the same.

Approved by: re (blanket)

Centralize _PATH_* definitions.

Submitted by: Tim Kientzle <kientzle@acm.org> (embellished by me)

The is_name and is_in_name macros are FUBAR'ed.
Due to the use of signed vs. unsigned chars on our various platforms, one gets
"warning: comparison is always true due to limited range of data type"
from GCC 3.3.

Quiet warnings about copyright[].

Fix references to non-existing or obsoleted man pages.

PR: docs/51480 (only a small part)
Submitted by: Diomidis D. Spinellis <dds@aueb.gr>

Document the -L and -P options to the cd and pwd commands as being
mutually exclusive. The fact that the most recent one specified on the
command line is the one that takes effect is an implementation detail and
users should not rely on this.

Flush the output buffers before forking a child process to avoid
the child process writing data that the parent should have written.

PR: 50051
MFC after: 2 weeks

Fixed (soon might be fatal) -Wformat warnings.

Third attempt at removing machdep.h and using ALIGN from <sys/param.h>.
The initial stack_block is staticly allocated and will be aligned
according to the alignment requirements of pointers, which does not
necessarily match the alignment enforced by ALIGN. To solve this a
more involved change is required: remove the static initial stack
and deal with an initial condition of not having a stack at all. This
change is therefore more risky than the previous ones, but unavoidable
(other than not using the platform default alignment).

Discussed with: tjr
Approved and reviewed by: tjr
Tested on: alpha, i386, ia64 and sparc64

Revert ALIGN change for the second and last time. I can't figure out
why this is breaking sparc64.

Second attempt at removing machdep.h and using ALIGN from <sys/param.h>.
The problem with the previous attempt, as noticed by Marcel, was that
stacknxt was being aligned to a pointer boundary instead of an
ALIGNBYTES + 1 boundary, which broke sparc64.