mirrors/coreutils
0
0
Fork 0
mirror of https://github.com/coreutils/coreutils.git synced 2024-12-11 19:04:13 +08:00
Code Issues Packages Projects Releases Wiki Activity
2880a90019
coreutils/lib/chdir-safer.c

85 lines
2.2 KiB
C
Raw Normal View History

(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
/* much like chdir(2), but safer
fix typo in comment
2006-01-10 04:32:08 +08:00
Copyright (C) 2005, 2006 Free Software Foundation, Inc.
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
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 */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "chdir-safer.h"
#include <stdbool.h>
#include <fcntl.h>
#include <errno.h>
Whoops; don't remove the include for unistd.h, since it defines fchdir.
2005-12-26 05:38:43 +08:00
#include <unistd.h>
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
#include <sys/types.h>
#include <sys/stat.h>
(SAME_INODE): Remove definition. Include "same-inode.h", instead.
2006-03-13 05:59:29 +08:00
#include "same-inode.h"
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
#ifndef O_DIRECTORY
# define O_DIRECTORY 0
#endif
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
#ifndef O_NOFOLLOW
(O_NOFOLLOW): Define, if necessary.
2005-12-23 16:28:14 +08:00
# define O_NOFOLLOW 0
#endif
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
/* Like chdir, but fail if DIR is a symbolic link to a directory (or
fix typo in comment
2006-01-10 04:32:08 +08:00
similar funny business), or if DIR is not readable. This avoids a
(chdir_no_follow): Don't bother trying to open directory for write access: POSIX says that must fail.
2005-12-27 15:54:37 +08:00
minor race condition between when a directory is created or statted
and when the process chdirs into it. */
(chdir_no_follow): Rewrite to use fchdir even when O_NOFOLLOW is not defined. Suggested by Eric Blake.
2005-12-23 20:00:26 +08:00
int
chdir_no_follow (char const *dir)
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
{
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
int result = 0;
int saved_errno;
(chdir_no_follow): Don't bother trying to open directory for write access: POSIX says that must fail.
2005-12-27 15:54:37 +08:00
int fd = open (dir,
O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK);
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
if (fd < 0)
(chdir_no_follow): Don't bother trying to open directory for write access: POSIX says that must fail.
2005-12-27 15:54:37 +08:00
return -1;
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
/* If open follows symlinks, lstat DIR and fstat FD to ensure that
they are the same file; if they are different files, set errno to
ELOOP (the same value that open uses for symlinks with
O_NOFOLLOW) so the caller can report a failure. */
if (! O_NOFOLLOW)
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
{
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
struct stat sb1;
result = lstat (dir, &sb1);
if (result == 0)
{
(chdir_no_follow): Move declaration of local, sb2, `down' into the scope where it is used. Note that on some systems this function also fails when DIR is a writable-yet-unreadable directory.
2005-12-27 02:53:58 +08:00
struct stat sb2;
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
result = fstat (fd, &sb2);
if (result == 0 && ! SAME_INODE (sb1, sb2))
{
errno = ELOOP;
result = -1;
}
}
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
}
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
if (result == 0)
result = fchdir (fd);
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
saved_errno = errno;
close (fd);
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
errno = saved_errno;
(chdir_no_follow): Don't include stdio.h, assert.h, unistd.h, fcntl--.h; not needed. (O_DIRECTORY): Define if not already defined. (chdir_no_follow): Revamp describing comment to match code more closely. Redo use of internal vars to avoid lint complaints. Work even if directory is writeable but not readable. Open with O_DIRECTORY | O_NOCTTY, for benefit of hosts that don't have O_NOFOLLOW. Use O_NONBLOCK (POSIX spelling) rather than O_NDELAY. Don't bother invoking fstat if open does not dereference symlink, since the result isn't used then. Don't assume file descriptor is positive; it might be zero now that we no longer include fcntl--.h (we don't need fcntl--.h since we immediately close the descriptor).
2005-12-26 05:35:38 +08:00
return result;
like chdir(2), but safer, if possible
2005-12-21 17:42:36 +08:00
}
Reference in New Issue Copy Permalink