/* Create /proc/self/fd-related names for subfiles of open directories.
- Copyright (C) 2006 Free Software Foundation, Inc.
+ Copyright (C) 2006, 2009-2010 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ 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.
+ 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
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#include <stdio.h>
#include <string.h>
+#include <unistd.h>
#include "dirname.h"
#include "intprops.h"
#include "same-inode.h"
#include "xalloc.h"
+/* The results of open() in this file are not used with fchdir,
+ and we do not leak fds to any single-threaded code that could use stdio,
+ therefore save some unnecessary work in fchdir.c.
+ FIXME - if the kernel ever adds support for multi-thread safety for
+ avoiding standard fds, then we should use open_safer. */
+#undef open
+#undef close
+
#define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/%s"
#define PROC_SELF_FD_NAME_SIZE_BOUND(len) \
{
static int proc_status = 0;
+ /* Make sure the caller gets ENOENT when appropriate. */
+ if (!*file)
+ {
+ buf[0] = '\0';
+ return buf;
+ }
+
if (! proc_status)
{
/* Set PROC_STATUS to a positive value if /proc/self/fd is
- reliable, and a negative value otherwise. Solaris 10
- /proc/self/fd mishandles "..", and any file name might expand
- to ".." after symbolic link expansion, so avoid /proc/self/fd
- if it mishandles "..". Solaris 10 has openat, but this
- problem is exhibited on code that built on Solaris 8 and
- running on Solaris 10. */
+ reliable, and a negative value otherwise. Solaris 10
+ /proc/self/fd mishandles "..", and any file name might expand
+ to ".." after symbolic link expansion, so avoid /proc/self/fd
+ if it mishandles "..". Solaris 10 has openat, but this
+ problem is exhibited on code that built on Solaris 8 and
+ running on Solaris 10. */
int proc_self_fd = open ("/proc/self/fd", O_RDONLY);
if (proc_self_fd < 0)
- proc_status = -1;
+ proc_status = -1;
else
- {
- struct stat proc_self_fd_dotdot_st;
- struct stat proc_self_st;
- char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof ".." - 1)];
- sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "..");
- proc_status =
- ((stat (dotdot_buf, &proc_self_fd_dotdot_st) == 0
- && stat ("/proc/self", &proc_self_st) == 0
- && SAME_INODE (proc_self_fd_dotdot_st, proc_self_st))
- ? 1 : -1);
- close (proc_self_fd);
- }
+ {
+ struct stat proc_self_fd_dotdot_st;
+ struct stat proc_self_st;
+ char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof ".." - 1)];
+ sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "..");
+ proc_status =
+ ((stat (dotdot_buf, &proc_self_fd_dotdot_st) == 0
+ && stat ("/proc/self", &proc_self_st) == 0
+ && SAME_INODE (proc_self_fd_dotdot_st, proc_self_st))
+ ? 1 : -1);
+ close (proc_self_fd);
+ }
}
if (proc_status < 0)