sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Add helper functions to copy strings into struct image_args.

Given a zeroed struct image_args with an allocated buf member,
exec_args_add_fname() must be called to install a file name (or NULL).
Then zero or more calls to exec_args_add_env() followed by zero or
more calls to exec_args_add_env(). exec_args_adjust_args() may be
called after args and/or env to allow an interpreter to be prepended to
the argument list.

To allow code reuse when adding arg and env variables, begin_envv
should be accessed with the accessor exec_args_get_begin_envv()
which handles the case when no environment entries have been added.

Use these functions to simplify exec_copyin_args() and
freebsd32_exec_copyin_args().

Reviewed by: kib
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D15468

Use C99 designated initializers for struct execsw

It it makes use slightly more clear and facilitates grepping.

sys/kern: adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

ANSI-fy exec_shell_imgact().

Fix a stray space while here.

PR: 223317
MFC after: 3 days

Allow multiple image activators to run on the same execution by changing
imgp->interpreted to a bitmask instead of, functionally, a bool. Each
imgactivator now requires its own flag in interpreted to indicate whether
or not it has already examined argv[0].

Change imgp->interpreted to an unsigned char to add one extra bit for
future use.

With this change, one can execute a shell script from a 64bit host native
make and still get the binmisc image activator to fire for the script
interpreter. Prior to this, execution would fail.

Phabric: https://reviews.freebsd.org/D696
Reviewed by: jhb@
MFC after: 4 weeks

The execution of the shebang script requires putting interpreter path,
possible option and script path in the place of argv[0] supplied to
execve(2). It is possible and valid for the substitution to be shorter
then the argv[0].

Avoid signed underflow in this case.

Submitted by: Devon H. O'Dell <devon.odell gmail com>
PR: kern/155321
MFC after: 1 week

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Fix exec_imgact_shell()'s handling of two error cases: (1) Previously, if
the first line of a script exceeded MAXSHELLCMDLEN characters, then
exec_imgact_shell() silently truncated the line and passed on the truncated
interpreter name or argument. Now, exec_imgact_shell() will fail and return
ENOEXEC, which is the commonly used errno among Unix variants for this type
of error. (2) Previously, exec_imgact_shell()'s check on the length of the
interpreter's name was ineffective. In other words, exec_imgact_shell()
could not possibly fail and return ENAMETOOLONG. The reason being that the
length of the interpreter name had to exceed MAXSHELLCMDLEN characters in
order that ENAMETOOLONG be returned. But, the search for the end of the
interpreter name stops after at most MAXSHELLCMDLEN - 2 characters are
scanned. (In the end, this particular error is eventually discovered
outside of exec_imgact_shell() and ENAMETOOLONG is returned. So, the real
effect of this second change is that the error is detected earlier, in
exec_imgact_shell().)

Update the definition of MAXINTERP to the actual limit on the size of
the interpreter name that has been in effect since r142453 (from
2005).

In collaboration with: kib

Introduce exec_alloc_args(). The objective being to encapsulate the
details of the string buffer allocation in one place.

Eliminate the portion of the string buffer that was dedicated to storing
the interpreter name. The pointer to the interpreter name can simply be
made to point to the appropriate argument string.

Reviewed by: kib

Change the order in which the file name, arguments, environment, and
shell command are stored in exec*()'s demand-paged string buffer. For
a "buildworld" on an 8GB amd64 multiprocessor, the new order reduces
the number of global TLB shootdowns by 31%. It also eliminates about
330k page faults on the kernel address space.

Change exec_shell_imgact() to use "args->begin_argv" consistently as
the start of the argument and environment strings. Previously, it
would sometimes use "args->buf", which is the start of the overall
buffer, but no longer the start of the argument and environment
strings. While I'm here, eliminate unnecessary passing of "&length"
to copystr(), where we don't actually care about the length of the
copied string.

Clean up the initialization of the exec map. In particular, use the
correct size for an entry, and express that size in the same way that
is used when an entry is allocated. The old size was one page too
large. (This discrepancy originated in 2004 when I rewrote
exec_map_first_page() to use sf_buf_alloc() instead of the exec map
for mapping the first page of the executable.)

Reviewed by: kib

- Import the HEAD csup code which is the basis for the cvsmode work.

Decontextualize the couplet VOP_GETATTR / VOP_SETATTR as the passed thread
was always curthread and totally unuseful.

Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>

When calculating arguments to the interpreter for the shebang script
executed by fexecve(2), imgp->args->fname is NULL. Moreover, there is
no way to recover the path to the script being executed.
Do what some other U*ixes do unconditionally, namely supply /dev/fd/n
as the script path when called from fexecve(). Document requirement of
having fdescfs mounted as caveat.

Fix a panic which could occur parsing #!-lines in a shell-script. If the
#!-line had multiple whitespace characters after the interpreter name, and
it did not have any options, then the code would do nasty things trying to
process a (non-existent) option-string which "ended before it began"...

Submitted by: Morten Johansen
Approved by: re (dwhite)

Remove the previous parsing-logic for arguments on the '#!'-line of shell
scripts. As far as I know, no one has needed the '#!#<' kludge to get at
the behavior implemented by the historical parsing.

Change the way options are parsed on the `#!'-line of a shell-script. Instead
of having the kernel parse that line and add an entry to the argument list for
each 'separate word' it finds, have it add only one entry which holds all
the words found on that line. The old behavior is useful in some situations,
but it does not match the way any other operating system will parse that line.

This has been discussed in the thread "Bug in #! processing - One More Time"
on the freebsd-arch mailing list (starting back on Feb 24, 2005). The first
few messages in that thread provide the background in much detail.

PR: 16393
Reviewed by: freebsd-arch

o Replace two while {} do loops with more appropriate do {} while loops. This
doesn't change functionality, but makes code more logical.

Obtained from: DrafonFlyBSD

o Use VOP_GETATTR() to obtain actual size of file and parse no more than that.
Previously, we parsed MAXSHELLCMDLEN characters regardless of the actual file
size. This makes the following working:

$ printf '#!/bin/echo' > /tmp/test.sh
$ chmod 755 /tmp/test.sh
$ /tmp/test.sh

Previously, attempts to execve() that shell script has been failing with bogus
ENAMETOOLONG.

PR: kern/64196
Submitted by: Magnus B.ckstr.m <b@etek.chalmers.se>

Try harder to not exceed MAXSHELLCMDLEN when parsing first line of shell
script. Otherwise it's possible to panic kernel by constructing a shell
script with first line not ending in '\n'.

Also, treat '\0' as line terminating character, which may me useful in
some situations.

Submitted by: gad

Fix build on AMD64 (and probably other arches where size_t != int).

Submitted by: Tinderbox
MFC after: 2 weeks

o Split out kernel part of execve(2) syscall into two parts: one that
copies arguments into the kernel space and one that operates
completely in the kernel space;

o use kernel-only version of execve(2) to kill another stackgap in
linuxlator/i386.

Obtained from: DragonFlyBSD (partially)
MFC after: 2 weeks

/* -> /*- for copyright notices, minor format tweaks as necessary

Don't treat # as a comment in interpreter specification line.
This is magic and no other operating system do so (i.e. Solaris, Tru64,
Linux, AIX, HP-UX, Irix, MacOS X, NetBSD).

Discussed on: current@
Reported by: S³awek ¯ak <zaks@prioris.mini.pw.edu.pl>

Use __FBSDID().

Correct typos, mostly s/ a / an / where appropriate. Some whitespace cleanup,
especially in troff files.

Remove reference to struct execve_args from struct imgact, which
describes an image activation instance. Instead, make use of the
existing fname structure entry, and introduce two new entries,
userspace_argv, and userspace_envv. With the addition of
mac_execve(), this divorces the image structure from the specifics
of the execve() system call, removes a redundant pointer, etc.
No semantic change from current behavior, but it means that the
structure doesn't depend on syscalls.master-generated includes.

There seems to be some redundant initialization of imgact entries,
which I have maintained, but which could probably use some cleaning
up at some point.

Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories

Return a more meaningful errno when the length of the interpreter
exceeds MAXSHELLCMDLEN to avoid secondary /bin/sh execution.

Update execve man page to reflect change.

Increase MAXSHELLCMDLEN to a slightly more meaningful value.

PR: kern/32106
Submitted by: b@etek.chalmers.se
Reviewed by: bsd
MFC after: 2 weeks

Fix #! script exec under linux emulation. If a script is exec'd from a
program running under linux emulation, the script binary is checked for
in /compat/linux first. Without this patch the wrong script binary
(i.e. the FreeBSD binary) will be run instead of the linux binary.
For example, #!/bin/sh, thus breaking out of linux compatibility mode.

This solves a number of problems people have had installing linux
software on FreeBSD boxes.

Allow comments in interpreter specification lines as in
#! /bin/sh # -*- perl -*-

This is simply "delete everything after the next '#', not counting the
first char in the line". No effort has been made to allow quoting,
backslash escaping or '#' in interpreter names.

The complies to POSIX 1003.2 in that Posix says the implementation is
free to choose whatever it likes.

PR: bin/16393

$Id$ -> $FreeBSD$

Fix a couple of warnings and some bitrot in comments.

*_execsw static structures cannot be const due to the way they interact
with EXEC_SET, DECLARE_MODULE, and module_register. Specifically,
module_register. We may eventually be able to make these const, but
not now.

*gulp*. Jordan specifically OK'ed this..

This is the bulk of the support for doing kld modules. Two linker_sets
were replaced by SYSINIT()'s. VFS's and exec handlers are self registered.
kld is now a superset of lkm. I have converted most of them, they will
follow as a seperate commit as samples.
This all still works as a static a.out kernel using LKM's.

Removed unused #includes.

Don't clobber user space argv0 memory on shell exec, mainly for vfork()
Fix another bug: if argv[0] is NULL, garbadge args might be added for
shell script
Submitted by: Tor Egge <Tor.Egge@idi.ntnu.no> (with yet one fault detect from me)

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Fixed the easy cases of const poisoning in the kernel. Cosmetic.

Killed sections 3 and 4 of my copyright as I don't agree with it (I believe
it to be unnecessarily restrictive). For tty_subr.c, update to my standard
copyright.

Staticized.

Added prototypes.

All:
Changed vnodep -> vp for consistency with the rest of the kernel, and
changed iparams -> imgp for brevity.

kern_exec.c:
Explicitly initialized some additional parts of the image_params struct
to avoid bzeroing it. Rewrote the set-id code to reduce the number of
logical tests. The rewrite exposed a mostly benign bug in the algorithm:
traced set-id images would get ktracing disabled even if the set-id didn't
happen for other reasons.

Remove prototype definitions from <sys/systm.h>.
Prototypes are located in <sys/sysproto.h>.

Add appropriate #include <sys/sysproto.h> to files that needed
protos from systm.h.

Add structure definitions to appropriate files that relied on sys/systm.h,
right before system call definition, as in the rest of the kernel source.

In kern_prot.c, instead of using the dummy structure "args", create
individual dummy structures named <syscall>_args. This makes
life easier for prototype generation.

Fix my copyright.

While in the real world, I had a bad case of being swapped out for a lot of
cycles. While waiting there I added a lot of the extra ()'s I have, (I have
never used LISP to any extent). So I compiled the kernel with -Wall and
shut up a lot of "suggest you add ()'s", removed a bunch of unused var's
and added a couple of declarations here and there. Having a lap-top is
highly recommended. My kernel still runs, yell at me if you kernel breaks.

Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.

Change all #includes to follow the current Berkeley style. Some of these
``changes'' are actually not changes at all, but CVS sometimes has trouble
telling the difference.

This also includes support for second-directory compiles. This is not
quite complete yet, as `config' doesn't yet do the right thing. You can
still make it work trivially, however, by doing the following:

rm /sys/compile
mkdir /usr/obj/sys/compile
ln -s M-. /sys/compile
cd /sys/i386/conf
config MYKERNEL
cd ../../compile/MYKERNEL
ln -s /sys @
rm machine
ln -s @/i386/include machine
make depend
make

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

Let the linker keep track of pseudo-devices needing initialization and
image activators, rather than listing them inline in the code.

Rename aout_imgact.c and shell_imgact.c to imgact_* for consistency.