Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r241046: libc: Use O_CLOEXEC for various internal file descriptors.

This fixes a race condition where another thread may fork(), unintentionally
passing the descriptor to the child process.

This commit only adds O_CLOEXEC flags to open() or openat() calls where no
fcntl(fd, F_SETFD, FD_CLOEXEC) follows.

MFC r232385 by ru: Remove 3 syscalls from opendir().

Finally removed the stat() and fstat() calls from the opendir() code.
They were made excessive in r205424 by opening with O_DIRECTORY.
Also eliminated the fcntl() call used to set FD_CLOEXEC by opening
with O_CLOEXEC.

(fdopendir() still checks that the passed descriptor is a directory,
and sets FD_CLOEXEC on it.)

The necessary kernel support for O_DIRECTORY and O_CLOEXEC was already in
9.0-RELEASE.

Discussed with: ru

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Let opendir() use O_DIRECTORY.

I am not removing the fstat() calls here, since we cannot yet assume
people will always run kernels that respect O_DIRECTORY.

Style: rename internal function to opendir_compar()

Pointed by: bde

Double checking my commit I found that comment saying that
POSIX 2008 and XSI 7require strcoll() for opendir() is not true.
I can't find such requirement in POSIX 2008 and XSI 7.

So, back out that part of my commit, returning old strcmp(), and remove
this misleading comment.

a) Use strcoll() in opendir() and alphasort() as POSIX 2008 requires.
It also matches now how our 'ls' works for years.

b) Remove comment expressed 2 fears:
1) One just simple describe how strcoll() works in _any_ context,
not for directories only. Are we plan to remove strcoll() from everything
just because it is little more complex than strcmp()? I doubt, and
directories give nothing different here. Moreover, strcoll() used
in 'ls' for years and nobody complaints yet.

2) Plain wrong statement about undefined strcoll() behaviour. strcoll()
always gives predictable results, falling back to strcmp() on any
trouble, see strcoll(3).

No objections from -current list discussion.

Do not rely on behaviour undefined by ANSI C, use thunks to adapt
alphasort-like interface to the comparision function required by
qsort() and qsort_r().

For opendir() thunk and alphasort(), comment on why we deviated from
POSIX by using strcmp() instead of strcoll().

Requested and reviewed by: bde
MFC after: 2 weeks

Modernize scandir(3) and alphasort(3) interfaces according to the IEEE
Std 1003.1-2008. Both Linux and Solaris conforms to the new definitions,
so we better follow too (older glibc used old BSDish alphasort prototype
and corresponding type of the comparision function for scandir). While
there, change the definitions of the functions to ANSI C and fix several
style issues nearby.

Remove requirement for "sys/types.h" include for functions from manpage.

POSIX also requires that alphasort(3) sorts as if strcoll(3) was used,
but leave the strcmp(3) call in the function for now.

Adapt in-tree callers of scandir(3) to new declaration. The fact that
select_sections() from catman(1) could modify supplied struct dirent is
a bug.

PR: standards/142255
MFC after: 2 weeks

Implement fdopendir(3) by splitting __opendir2() into two parts, the upper part
deals with the usual __opendir2() calls, and the rest part with an interface
translator to expose fdopendir(3) functionality. Manual page was obtained from
kib@'s work for *at(2) system calls.

Style fixes to opendir.c:
- Use /*- for copyright block;
- ANSIfy.

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Avoid using void pointers in additive expressions.

PR: 56653

Make sure we initialise dirp->dd_size if we aren't reading a unionfs
directory.

Special thanks to: valgrind

Catch up with the renaming of the "union" filesystem to "unionfs".
Fixes a problem where directory entries could show up twice: once
on the top layer of the union stack, and once on the bottom layer.

Approved by: re (rwatson)

#include <string.h> for strcmp()'s prototype.

Fix SCM ID's.

Compensate for "Compensate for header dethreading" by backing it out.

Compensate for header dethreading.

Fix directory reads of MNT_UNION mounts, where entries present in both
layers would be displayed twice.

PR: bin/26498
Submitted by: Olliver Fromme <olli@secnetix.de>

Fix style bug that was introduced.

Remove _THREAD_SAFE and make libc thread-safe by default by
adding (weak definitions to) stubs for some of the pthread
functions. If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
__sys_foo - actual system call
_foo - weak definition to __sys_foo
foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo. In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde). All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes. <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE. We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by: -arch

Move telldir position recording type definitions and prototypes
to "telldir.h" in order to prevent namespace pollution in
<dirent.h> (which was including <sys/queue.h>).

Add $FreeBSD$ to rewinddir.c and seekdir.c.

Cleanup XXXdir functions to eliminate global hash table of
telldir positions. This will allow (future) locking on a
per-DIR basis (for MT-safety). For now, this change does
the following:

o Remove the hash table from telldir.c. Recode to use queue
macros.

o Remove 'const' from 'telldir(const DIR *)'.

o Remove 'register' variables as suggested in a recent
thread.

No response from: -current

Simplify sytem call renaming. Instead of _foo() <-- _libc_foo <-- foo(),
just use _foo() <-- foo(). In the case of a libpthread that doesn't do
call conversion (such as linuxthreads and our upcoming libpthread), this
is adequate. In the case of libc_r, we still need three names, which are
now _thread_sys_foo() <-- _foo() <-- foo().

Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(),
nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo().

Remove all internal libc usage of: creat(), pause(), sleep(), system(),
tcdrain(), wait(), and waitpid().

Make thread cancellation fully POSIX-compliant.

Suggested by: deischen

Add three-tier symbol naming in support of POSIX thread cancellation
points. For library functions, the pattern is __sleep() <--
_libc_sleep() <-- sleep(). The arrows represent weak aliases. For
system calls, the pattern is _read() <-- _libc_read() <-- read().

Replace memory leaking instances of realloc with non-leaking reallocf.
In some cases replace if (a == null) a = malloc(x); else a =
realloc(a, x); with simple reallocf(a, x). Per ANSI-C, this is
guaranteed to be the same thing.

I've been running these on my system here w/o ill effects for some
time. However, the CTM-express is at part 6 of 34 for the CAM
changes, so I've not been able to do a build world with the CAM in the
tree with these changes. Shouldn't impact anything, but...

Cast pointer to a long instead of an int to keep a 64-bit compiler
happy. The code works either way, but I like a clean compile.

Fixed errors in the Lite2 merge. Some style changes were mismerged.
My changes to preserve errno across free() and close() and to report
fstat() errors properly were blown away.

Updated the FreeBSD changes to match the Lite2 style fixes.

Merge from Lite2:
filesystem include updates, duplicate group suppression, cleanups,
filesystem whiteout support (unionfs), bidir popen().

Cache the result of getpagesize() so we only make one syscall.
Use getpagesize instead of CLBYTES.

stat() before open() because opening of special files may be harmful.

Fix bugs in opendir():
- it succeeded on non-directories (see POSIX 5.1.2.4).
- it hung on (non-open) named pipes.
- it leaked memory if the second malloc() failed.
- it didn't preserve errno across errors in close().

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Lib Sources