Use faccessat, not access, when checking file permissions.

* .bzrignore: Add lib/fcntl.h.
* configure.ac (euidaccess): Remove check; gnulib does this for us now.
(gl_FCNTL_O_FLAGS): Define a dummy version.
* lib/at-func.c, lib/euidaccess.c, lib/faccessat.c, lib/fcntl.in.h:
* lib/getgroups.c, lib/group-member.c, lib/root-uid.h:
* lib/xalloc-oversized.h, m4/euidaccess.m4, m4/faccessat.m4:
* m4/fcntl_h.m4, m4/getgroups.m4, m4/group-member.m4:
New files, from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* admin/merge-gnulib (GNULIB_MODULES): Add faccessat.
(GNULIB_TOOL_FLAGS): Avoid at-internal, fchdir, malloc-posix,
openat-die, openat-h, save-cwd.  Do not avoid fcntl-h.
Omit gnulib's m4/fcntl-o.m4.
* nt/inc/ms-w32.h (AT_FDCWD, AT_EACCESS): New symbols.
(access): Remove.
(faccessat): New macro.
* src/Makefile.in (LIB_EACCESS): New macro.
(LIBES): Use it.
* src/callproc.c (init_callproc):
* src/charset.c (init_charset):
* src/fileio.c (check_existing, check_executable):
* src/lread.c (openp, load_path_check):
* src/process.c (allocate_pty):
* src/xrdb.c (file_p):
Use faccessat, not access or euidaccess.  Use symbolic names
instead of integers for the flags, as they're portable now.
* src/charset.c, src/xrdb.c: Include <fcntl.h>, for the new flags used.
* src/fileio.c (Ffile_readable_p):
Use faccessat, not stat + open + close.
(file_directory_p): New function, which uses 'stat' on most places
but 'access' (for efficiency) if WINDOWSNT.
* src/fileio.c (Ffile_directory_p, Fset_file_times):
* src/xrdb.c (file_p): Use file_directory_p.
* src/lisp.h (file_directory_p): New decl.
* src/lread.c (openp): When opening a file, use fstat rather than
stat, as that avoids a permissions race.  When not opening a file,
use file_directory_p rather than stat.
* src/process.c, src/sysdep.c, src/term.c: All uses of '#ifdef O_NONBLOCK'
changed to '#if O_NONBLOCK', to accommodate gnulib O_* tyle.
* src/w32.c (sys_faccessat): Rename from sys_access and switch to
faccessat's API.  All uses changed.

Fixes: debbugs:12632

2 files changed, 16 insertions, 5 deletions

diff --git a/admin/ChangeLog b/admin/ChangeLog
index e21293d618d..6d08bf7c37e 100644
--- a/admin/ChangeLog
+++ b/admin/ChangeLog
@@ -1,3 +1,11 @@
+2012-10-19  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Use faccessat, not access, when checking file permissions (Bug#12632).
+        * merge-gnulib (GNULIB_MODULES): Add faccessat.
+        (GNULIB_TOOL_FLAGS): Avoid at-internal, fchdir, malloc-posix,
+        openat-die, openat-h, save-cwd.  Do not avoid fcntl-h.
+        Omit gnulib's m4/fcntl-o.m4.
+
 2012-10-12  Kenichi Handa  <handa@gnu.org>
 
         * charsets/Makefile (JISC6226.map): Add missing mappings.
diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 7fc0b5f4844..3c4d8e8058d 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -28,7 +28,7 @@ GNULIB_URL=git://git.savannah.gnu.org/gnulib.git
 GNULIB_MODULES='
   alloca-opt c-ctype c-strcase
   careadlinkat crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512
-  dtoastr dtotimespec dup2 environ execinfo
+  dtoastr dtotimespec dup2 environ execinfo faccessat
   filemode getloadavg getopt-gnu gettime gettimeofday
   ignore-value intprops largefile lstat
   manywarnings mktime pselect pthread_sigmask readlink
@@ -39,9 +39,12 @@ GNULIB_MODULES='
 '
 
 GNULIB_TOOL_FLAGS='
-  --avoid=errno --avoid=fcntl --avoid=fcntl-h --avoid=fstat
-  --avoid=msvc-inval --avoid=msvc-nothrow
-  --avoid=raise --avoid=select --avoid=sigprocmask --avoid=sys_types
+  --avoid=at-internal
+  --avoid=errno --avoid=fchdir --avoid=fcntl --avoid=fstat
+  --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow
+  --avoid=openat-die --avoid=openat-h
+  --avoid=raise
+  --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=sys_types
   --avoid=threadlib
   --conditional-dependencies --import --no-changelog --no-vc-files
   --makefile-name=gnulib.mk
@@ -85,7 +88,7 @@ test -x "$gnulib_srcdir"/gnulib-tool || {
 }
 
 "$gnulib_srcdir"/gnulib-tool --dir="$src" $GNULIB_TOOL_FLAGS $GNULIB_MODULES &&
-rm -- "$src"m4/gnulib-cache.m4 "$src"m4/warn-on-use.m4 &&
+rm -- "$src"m4/fcntl-o.m4 "$src"m4/gnulib-cache.m4 "$src"m4/warn-on-use.m4 &&
 cp -- "$gnulib_srcdir"/build-aux/texinfo.tex "$src"doc/misc &&
 cp -- "$gnulib_srcdir"/build-aux/move-if-change "$src"build-aux &&
 autoreconf -i -I m4 -- ${src:+"$src"}