ln: Improve link(1) variant of ln(1).

* Give link(1) its own usage message.
* Use getprogname(3) instead of rolling our own.
* Verify that the target file does not already exist.
* Add tests specific to link(1).

MFC after: 3 days
Sponsored by: Klara, Inc.
Reviewed by: allanjude
Differential Revision: https://reviews.freebsd.org/D44635

ln: Use stdbool, style nits.

MFC after: 1 week
Sponsored by: Klara, Inc.
Reviewed by: imp, allanjude
Differential Revision: https://reviews.freebsd.org/D44511

Remove copyright strings ifdef'd out

We've ifdef'd out the copyright strings for some time now. Go ahead and
remove the ifdefs. Plus whatever other detritis was left over from other
recent removals. These copyright strings are present in the comments and
are largely from CSRG's attempt at adding their copyright to every
binary file (which modern interpretations of the license doesn't
require).

Sponsored by: Netflix

bin: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

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

General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

ln(1): fix -F behavior

When '-F' option is used, the target directory needs to be unlinked.
Currently, the modified target ("target/source") is being unlinked, and
since it doesn't yet exist, the original target isn't removed.
This is fixed by skipping the block where target is modified to
"target/source" when '-F' option is set.
Hence, a symbolic link (with the same name as of the original target) to
the source_file is produced.

Update the test for ln(1) to reflect fix for option '-F'

MFC after: 1 month
PR: 219943
Differential Revision: D11167
Submitted by: shivansh
Sponsored by: Google (GSoC 2017)

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

Add 'static' where able.

Put some static keywords in the source code.

For these simple utilities, it doesn't harm to make all global variables
static. In fact, this allows the compiler to perform better forms of
optimisation and analysis.

bin: Prefer strrchr() to rindex().

This removes the last index/rindex usage from /bin.

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

MFC r207021: ln: Allow a trailing slash when creating a link to a directory.

In the 'ln source... directory' synopsis, the basename of each source
determines the name of the created link. Determine this using basename(3)
instead of strrchr(..., '/') which is incorrect if the pathname ends in a
slash.

PR: 121568

MFC r206773: ln: Do not delete a file by hardlinking it to itself.

Two pathnames refer to the same directory entry iff the directories match
and the final components' names match.

Example: (assuming file1 is an existing file)
ln -f file1 file1
This now fails while leaving file1 intact. It used to delete file1 and then
complain it cannot be linked because it is gone.

With -i, this error is detected before the question is asked.

ln: Allow a trailing slash when creating a link to a directory.

In the 'ln source... directory' synopsis, the basename of each source
determines the name of the created link. Determine this using basename(3)
instead of strrchr(..., '/') which is incorrect if the pathname ends in a
slash.

The patch is somewhat changed to allow for basename(3) implementations that
change the passed pathname, and to fix the -w option's checking also.
The code to compare directory entries only applies to hard links, which
cannot be created to directories using ln.

Example:
ln -s /etc/defaults/ /tmp
This should create a symlink named defaults.

PR: 121568
Submitted by: Ighighi
MFC after: 1 week

ln: Refuse deleting a directory entry by hardlinking it to itself.

Two pathnames refer to the same directory entry iff the directories match
and the final components' names match.

Example: (assuming file1 is an existing file)
ln -f file1 file1
This now fails while leaving file1 intact. It used to delete file1 and then
complain it cannot be linked because it is gone.

With -i, this error is detected before the question is asked.

MFC after: 2 weeks

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

Allow creating hard links to symlinks using ln(1).

This implements the POSIX.1-2008 -L and -P flags.

The default remains to create hard links to the target of symlinks.

Approved by: re (kib), ed (mentor)

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

Unbreak last commit to ln for amd64.

Cast string precision to `int'. amd64 systems warn about the
field precision being `long int' if we don't, and pathnames are
normally short enough to fit in an `int'.

Noticed by: pav

Add a -w warning flag to ln(1). When the -w option is enabled,
ln(1) checks to see if the source of a symlink, i.e. the file it
should point to actually exists. The default is the old ln
behavior, that does not check, to avoid surprising people who may
be using ln(1) in scripts or other non-interactive places.

PR: bin/7265
Submitted by: Joel Ray Holveck, detlev!joelh at mail.camalott.com
MFC after: 2 weeks

Express in the usage() and SYNOPSIS that -F depends on -s, and
that -f and -i are exclusive.

Swap "source"/"target" where appropriate, to match documentation.

Add '-F' option which allows to delete existing empty directories, when
creating symbolic links.

PR: bin/92149
Submitted by: Eugene Grosbein <eugen grosbein.pp.ru>

Sync program's usage() with manpage's SYNOPSIS.

/*- or .\"- or #- to begin license clauses.

Remove clause 3 from the UCB licenses.

OK'ed by: imp, core

Quiet warnings about copyright[].

Fix an easy WARNS.

Consistently use __FBSDID

Check that snprintf() does not truncate the destination pathname when
linking into a directory.

Reject options, handle "--" end-of-options marker in link(1).

Add semicolon to empty default case to silence warning.

Fix warnings inspired by lint, a commercial lint and WARNS=4.

o __P has been reoved
o Old-style K&R declarations have been converted to new C89 style
o register has been removed
o prototype for main() has been removed (gcc3 makes it an error)
o int main(int argc, char *argv[]) is the preferred main definition.
o Attempt to not break style(9) conformance for declarations more than
they already are.

Use PATH_MAX in preference to MAXPATHLEN.

Also sort declarations per style(9) (big arrays come last) while I'm
in the area.

Silence WARNS=2 and BDECFLAGS on i386 and alpha

MFC After: 1 week

Bring in `-h' compatability option and its alias `-n' to match NetBSD and GNU
semantics.

style(9) Reviewed by:
Obtained from: NetBSD

Fix style bugs and inconsistencies introduced in rev 1.16.

Submitted by: bde

Don't explicitly declare optarg and optind. These are declared in
unistd.h, which is already included.

Add the -i option, as found in rm(1), which provides an interactive
mode in which the user is prompted for confirmation before an
existing file is replaced.

Submitted by: alex

Add link(1) and unlink(1) as special cases of ln(1) and rm(1)
respectively, in accordance with SUSv2.

This differs from the approach taken in NetBSD, but provides
less obscure error messages in at least the EISDIR case and
does not take up additional disk space for new binaries.

PR: 13071
PR: 13074
Requested by: James Howard <howardjp@wam.umd.edu>

Add verbose processing flag.

$Id$ -> $FreeBSD$

Correct use of .Nm. Add rcsid.

Cosmetic change in usage string.

compare return value from getopt against -1 rather than EOF, per the final
posix standard on the topic.

Revert $FreeBSD$ to $Id$

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.

-Wall cleaning.

Nuke the undocumented -F flag, since it doesn't do anything anymore.

It used to allow root to hard-link directories (and screw up programs that
expexted the ".." entry to point to the parent dir)

Use lstat() instead of stat() for checking if the final source file exists,
so that `ln -fs' works when the source is a symlink pointing to a non-
existent file.

Added $Id$

fix ln to accept -f again. Thanks Bruce. Seems that Joe Grosch isn't
quite as safe as I thought. I will have to look much closer on his
patches. Damn.

/home/phk/jg

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