/* provide a chdir function that tries not to fail due to ENAMETOOLONG
- Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2004-2010 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 "chdir-long.h"
+#include <assert.h>
+#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
-#include <errno.h>
#include <stdio.h>
-#include <assert.h>
-
-#include "openat.h"
#ifndef PATH_MAX
# error "compile this file only if your system defines PATH_MAX"
#endif
+/* The results of openat() in this file are not leaked to any
+ single-threaded code that could use stdio.
+ FIXME - if the kernel ever adds support for multi-thread safety for
+ avoiding standard fds, then we should use openat_safer. */
+
struct cd_buf
{
int fd;
cdb_advance_fd (struct cd_buf *cdb, char const *dir)
{
int new_fd = openat (cdb->fd, dir,
- O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK);
+ O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK);
if (new_fd < 0)
return -1;
code in the following loop cleaner. */
if (n_leading_slash == 2)
{
- int err;
- /* Find next slash.
- We already know that dir[2] is neither a slash nor '\0'. */
- char *slash = memchr (dir + 3, '/', dir_end - (dir + 3));
- if (slash == NULL)
- {
- errno = ENAMETOOLONG;
- return -1;
- }
- *slash = '\0';
- err = cdb_advance_fd (&cdb, dir);
- *slash = '/';
- if (err != 0)
- goto Fail;
- dir = find_non_slash (slash + 1);
+ int err;
+ /* Find next slash.
+ We already know that dir[2] is neither a slash nor '\0'. */
+ char *slash = memchr (dir + 3, '/', dir_end - (dir + 3));
+ if (slash == NULL)
+ {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ *slash = '\0';
+ err = cdb_advance_fd (&cdb, dir);
+ *slash = '/';
+ if (err != 0)
+ goto Fail;
+ dir = find_non_slash (slash + 1);
}
else if (n_leading_slash)
{
- if (cdb_advance_fd (&cdb, "/") != 0)
- goto Fail;
- dir += n_leading_slash;
+ if (cdb_advance_fd (&cdb, "/") != 0)
+ goto Fail;
+ dir += n_leading_slash;
}
assert (*dir != '/');
while (PATH_MAX <= dir_end - dir)
{
- int err;
- /* Find a slash that is PATH_MAX or fewer bytes away from dir.
- I.e. see if there is a slash that will give us a name of
- length PATH_MAX-1 or less. */
- char *slash = memrchr (dir, '/', PATH_MAX);
- if (slash == NULL)
- {
- errno = ENAMETOOLONG;
- return -1;
- }
-
- *slash = '\0';
- assert (slash - dir < PATH_MAX);
- err = cdb_advance_fd (&cdb, dir);
- *slash = '/';
- if (err != 0)
- goto Fail;
-
- dir = find_non_slash (slash + 1);
+ int err;
+ /* Find a slash that is PATH_MAX or fewer bytes away from dir.
+ I.e. see if there is a slash that will give us a name of
+ length PATH_MAX-1 or less. */
+ char *slash = memrchr (dir, '/', PATH_MAX);
+ if (slash == NULL)
+ {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+
+ *slash = '\0';
+ assert (slash - dir < PATH_MAX);
+ err = cdb_advance_fd (&cdb, dir);
+ *slash = '/';
+ if (err != 0)
+ goto Fail;
+
+ dir = find_non_slash (slash + 1);
}
if (dir < dir_end)
{
- if (cdb_advance_fd (&cdb, dir) != 0)
- goto Fail;
+ if (cdb_advance_fd (&cdb, dir) != 0)
+ goto Fail;
}
if (cdb_fchdir (&cdb) != 0)
{
int saved_errno = errno;
if (feof (stdin))
- exit (0);
+ exit (0);
error (EXIT_FAILURE, saved_errno,
- "reading standard input");
+ "reading standard input");
}
else if (len == 0)
exit (0);
if (chdir_long (line) != 0)
error (EXIT_FAILURE, errno,
- "chdir_long failed: %s", line);
+ "chdir_long failed: %s", line);
if (argc <= 1)
{
/* Using `pwd' here makes sense only if it is a robust implementation,
- like the one in coreutils after the 2004-04-19 changes. */
+ like the one in coreutils after the 2004-04-19 changes. */
char const *cmd = "pwd";
execlp (cmd, (char *) NULL);
error (EXIT_FAILURE, errno, "%s", cmd);