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/* provide a replacement openat function
Copyright (C) 2004, 2005 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 2, 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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* written by Jim Meyering */
#include <config.h>
#include "openat.h"
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
#include "save-cwd.h"
#include "gettext.h"
#define _(msgid) gettext (msgid)
/* Replacement for Solaris' openat function.
<http://www.google.com/search?q=openat+site:docs.sun.com>
Simulate it by doing save_cwd/fchdir/open/restore_cwd.
If either the save_cwd or the restore_cwd fails (relatively unlikely,
and usually indicative of a problem that deserves close attention),
then give a diagnostic and exit nonzero.
Otherwise, upon failure, set errno and return -1, as openat does.
Upon successful completion, return a file descriptor. */
int
rpl_openat (int fd, char const *file, int flags, ...)
{
struct saved_cwd saved_cwd;
int saved_errno;
int new_fd;
mode_t mode = 0;
if (flags & O_CREAT)
{
va_list arg;
va_start (arg, flags);
/* Assume that mode_t is passed compatibly with mode_t's type
after argument promotion. */
mode = va_arg (arg, mode_t);
va_end (arg);
}
if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
return open (file, flags, mode);
if (save_cwd (&saved_cwd) != 0)
openat_save_fail (errno);
if (fchdir (fd) != 0)
{
saved_errno = errno;
free_cwd (&saved_cwd);
errno = saved_errno;
return -1;
}
new_fd = open (file, flags, mode);
saved_errno = errno;
if (restore_cwd (&saved_cwd) != 0)
openat_restore_fail (errno);
free_cwd (&saved_cwd);
errno = saved_errno;
return new_fd;
}
/* Replacement for Solaris' function by the same name.
<http://www.google.com/search?q=fdopendir+site:docs.sun.com>
Simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd.
If either the save_cwd or the restore_cwd fails (relatively unlikely,
and usually indicative of a problem that deserves close attention),
then give a diagnostic and exit nonzero.
Otherwise, this function works just like Solaris' fdopendir.
W A R N I N G:
Unlike the other fd-related functions here, this one
effectively consumes its FD parameter. The caller should not
close or otherwise manipulate FD after calling this function. */
DIR *
fdopendir (int fd)
{
struct saved_cwd saved_cwd;
int saved_errno;
DIR *dir;
if (fd == AT_FDCWD)
return opendir (".");
if (save_cwd (&saved_cwd) != 0)
openat_save_fail (errno);
if (fchdir (fd) != 0)
{
saved_errno = errno;
free_cwd (&saved_cwd);
close (fd);
errno = saved_errno;
return NULL;
}
dir = opendir (".");
saved_errno = errno;
if (restore_cwd (&saved_cwd) != 0)
openat_restore_fail (errno);
free_cwd (&saved_cwd);
close (fd);
errno = saved_errno;
return dir;
}
/* Replacement for Solaris' function by the same name.
<http://www.google.com/search?q=fstatat+site:docs.sun.com>
Simulate it by doing save_cwd/fchdir/(stat|lstat)/restore_cwd.
If either the save_cwd or the restore_cwd fails (relatively unlikely,
and usually indicative of a problem that deserves close attention),
then give a diagnostic and exit nonzero.
Otherwise, this function works just like Solaris' fstatat. */
int
fstatat (int fd, char const *file, struct stat *st, int flag)
{
struct saved_cwd saved_cwd;
int saved_errno;
int err;
if (fd == AT_FDCWD)
return (flag == AT_SYMLINK_NOFOLLOW
? lstat (file, st)
: stat (file, st));
if (save_cwd (&saved_cwd) != 0)
openat_save_fail (errno);
if (fchdir (fd) != 0)
{
saved_errno = errno;
free_cwd (&saved_cwd);
errno = saved_errno;
return -1;
}
err = (flag == AT_SYMLINK_NOFOLLOW
? lstat (file, st)
: stat (file, st));
saved_errno = errno;
if (restore_cwd (&saved_cwd) != 0)
openat_restore_fail (errno);
free_cwd (&saved_cwd);
errno = saved_errno;
return err;
}
/* Replacement for Solaris' function by the same name.
<http://www.google.com/search?q=unlinkat+site:docs.sun.com>
Simulate it by doing save_cwd/fchdir/(unlink|rmdir)/restore_cwd.
If either the save_cwd or the restore_cwd fails (relatively unlikely,
and usually indicative of a problem that deserves close attention),
then give a diagnostic and exit nonzero.
Otherwise, this function works just like Solaris' unlinkat. */
int
unlinkat (int fd, char const *file, int flag)
{
struct saved_cwd saved_cwd;
int saved_errno;
int err;
if (fd == AT_FDCWD)
return (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file));
if (save_cwd (&saved_cwd) != 0)
openat_save_fail (errno);
if (fchdir (fd) != 0)
{
saved_errno = errno;
free_cwd (&saved_cwd);
errno = saved_errno;
return -1;
}
err = (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file));
saved_errno = errno;
if (restore_cwd (&saved_cwd) != 0)
openat_restore_fail (errno);
free_cwd (&saved_cwd);
errno = saved_errno;
return err;
}
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