coreutils/lib/openat.c

88 lines
2.3 KiB
C

/* provide a replacement openat function
Copyright (C) 2004 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* written by Jim Meyering */
#include <config.h>
/* Disable the definition of openat to rpl_openat (from config.h) in this
file. Otherwise, we'd get conflicting prototypes for rpl_openat on
most systems. */
#undef openat
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include "openat.h"
#include "error.h"
#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 fchdir or the restore_cwd fails, then exit nonzero. */
int
rpl_openat (int fd, char const *filename, int flags, ...)
{
struct saved_cwd saved_cwd;
int saved_errno = 0;
int new_fd;
mode_t mode;
if (flags & O_CREAT)
{
va_list arg;
va_start (arg, flags);
mode = va_arg (arg, mode_t);
va_end (arg);
}
else
{
mode = 0;
}
if (fd == AT_FDCWD || *filename == '/')
return open (filename, flags, mode);
if (save_cwd (&saved_cwd) != 0)
error (EXIT_FAILURE, errno,
_("openat: unable to record current working directory"));
if (fchdir (fd) != 0)
{
free_cwd (&saved_cwd);
return -1;
}
new_fd = open (filename, flags, mode);
if (new_fd < 0)
saved_errno = errno;
if (restore_cwd (&saved_cwd) != 0)
error (EXIT_FAILURE, errno,
_("openat: unable to restore working directory"));
errno = saved_errno;
return new_fd;
}