/* much like chdir(2), but safer
- Copyright (C) 2005-2006, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2005-2006, 2008-2011 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
#include <sys/stat.h>
#include "same-inode.h"
-#ifndef ELOOP
-# define ELOOP 0
+#ifndef HAVE_READLINK
+# define HAVE_READLINK 0
#endif
/* Like chdir, but fail if DIR is a symbolic link to a directory (or
- similar funny business), or if DIR is not readable. This avoids a
- minor race condition between when a directory is created or statted
- and when the process chdirs into it. */
+ similar funny business). This avoids a minor race condition
+ between when a directory is created or statted and when the process
+ chdirs into it.
+
+ On older systems lacking full support for O_SEARCH, this function
+ can also fail if DIR is not readable. */
int
chdir_no_follow (char const *dir)
{
int result = 0;
int saved_errno;
int fd = open (dir,
- O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK);
+ O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK);
if (fd < 0)
return -1;
/* 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)
+ O_NOFOLLOW) so the caller can report a failure.
+ Skip this check if HAVE_READLINK == 0, which should be the case
+ on any system that lacks symlink support. */
+ if (HAVE_READLINK && ! HAVE_WORKING_O_NOFOLLOW)
{
struct stat sb1;
result = lstat (dir, &sb1);
if (result == 0)
- {
- struct stat sb2;
- result = fstat (fd, &sb2);
- if (result == 0 && ! SAME_INODE (sb1, sb2))
- {
- errno = ELOOP;
- result = -1;
- }
- }
+ {
+ struct stat sb2;
+ result = fstat (fd, &sb2);
+ if (result == 0 && ! SAME_INODE (sb1, sb2))
+ {
+ errno = ELOOP;
+ result = -1;
+ }
+ }
}
if (result == 0)