/* 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) 2004-2014 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;
};
-static inline void
+static void
cdb_init (struct cd_buf *cdb)
{
cdb->fd = AT_FDCWD;
}
-static inline int
+static int
cdb_fchdir (struct cd_buf const *cdb)
{
return fchdir (cdb->fd);
}
-static inline void
+static void
cdb_free (struct cd_buf const *cdb)
{
if (0 <= cdb->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_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK);
if (new_fd < 0)
return -1;
}
/* Return a pointer to the first non-slash in S. */
-static inline char *
+static char * _GL_ATTRIBUTE_PURE
find_non_slash (char const *s)
{
size_t n_slash = strspn (s, "/");
name. It handles an arbitrarily long directory name by operating
on manageable portions of the name. On systems without the openat
syscall, this means changing the working directory to more and more
- `distant' points along the long directory name and then restoring
+ "distant" points along the long directory name and then restoring
the working directory. If any of those attempts to save or restore
the working directory fails, this function exits nonzero.
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. */
+ /* Using 'pwd' here makes sense only if it is a robust implementation,
+ 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);
projects / gnulib.git / blobdiff