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emacs/lib/stat.c
Paul Eggert ae0d725005 [ChangeLog]
Work around some portability problems with symlinks.
* Makefile.in (GNULIB_MODULES): Add lstat, readlink, symlink.
* configure.in (lstat, HAVE_LSTAT): Remove special hack.
* lib/lstat.c, lib/readlink.c, lib/stat.c, lib/symlink.c:
* m4/dos.m4, m4/lstat.m4, m4/readlink.m4, m4/stat.m4, m4/symlink.m4:
New files, automatically generated from gnulib.
* aclocal.m4, configure, lib/Makefile.in, lib/gnulib.mk:
* lib/stdlib.in.h, m4/gl-comp.m4, m4/stdlib_h.m4: Regenerate.

2011-02-22  Paul Eggert  <eggert@cs.ucla.edu>
[src/ChangeLog]
Work around some portability problems with symlinks.
* fileio.c (Frename_file, Fmake_symbolic_link, Ffile_symlink_p):
Simplify the code by assuming that the readlink and symlink calls
exist, even if they always fail on this host.
(Ffile_readable_p): Likewise, for fifos.
* config.in: Regenerate.
2011-02-22 11:30:07 -08:00

105 lines
3.3 KiB
C

/* Work around platform bugs in stat.
Copyright (C) 2009-2011 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* written by Eric Blake */
#include <config.h>
/* Get the original definition of stat. It might be defined as a macro. */
#define __need_system_sys_stat_h
#include <sys/types.h>
#include <sys/stat.h>
#undef __need_system_sys_stat_h
static inline int
orig_stat (const char *filename, struct stat *buf)
{
return stat (filename, buf);
}
/* Specification. */
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <string.h>
/* Store information about NAME into ST. Work around bugs with
trailing slashes. Mingw has other bugs (such as st_ino always
being 0 on success) which this wrapper does not work around. But
at least this implementation provides the ability to emulate fchdir
correctly. */
int
rpl_stat (char const *name, struct stat *st)
{
int result = orig_stat (name, st);
#if REPLACE_FUNC_STAT_FILE
/* Solaris 9 mistakenly succeeds when given a non-directory with a
trailing slash. */
if (result == 0 && !S_ISDIR (st->st_mode))
{
size_t len = strlen (name);
if (ISSLASH (name[len - 1]))
{
errno = ENOTDIR;
return -1;
}
}
#endif /* REPLACE_FUNC_STAT_FILE */
#if REPLACE_FUNC_STAT_DIR
if (result == -1 && errno == ENOENT)
{
/* Due to mingw's oddities, there are some directories (like
c:\) where stat() only succeeds with a trailing slash, and
other directories (like c:\windows) where stat() only
succeeds without a trailing slash. But we want the two to be
synonymous, since chdir() manages either style. Likewise, Mingw also
reports ENOENT for names longer than PATH_MAX, when we want
ENAMETOOLONG, and for stat("file/"), when we want ENOTDIR.
Fortunately, mingw PATH_MAX is small enough for stack
allocation. */
char fixed_name[PATH_MAX + 1] = {0};
size_t len = strlen (name);
bool check_dir = false;
if (PATH_MAX <= len)
errno = ENAMETOOLONG;
else if (len)
{
strcpy (fixed_name, name);
if (ISSLASH (fixed_name[len - 1]))
{
check_dir = true;
while (len && ISSLASH (fixed_name[len - 1]))
fixed_name[--len] = '\0';
if (!len)
fixed_name[0] = '/';
}
else
fixed_name[len++] = '/';
result = orig_stat (fixed_name, st);
if (result == 0 && check_dir && !S_ISDIR (st->st_mode))
{
result = -1;
errno = ENOTDIR;
}
}
}
#endif /* REPLACE_FUNC_STAT_DIR */
return result;
}