/* fchdir replacement.
- Copyright (C) 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2006-2013 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/>. */
#include <config.h>
+/* Specification. */
+#include <unistd.h>
+
+#include <assert.h>
+#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
-#include <stdarg.h>
+#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
-#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
-#include <dirent.h>
-#include "canonicalize.h"
-#include "dirfd.h"
+#include "dosname.h"
+#include "filenamecat.h"
+
+#ifndef REPLACE_OPEN_DIRECTORY
+# define REPLACE_OPEN_DIRECTORY 0
+#endif
/* This replacement assumes that a directory is not renamed while opened
- through a file descriptor. */
+ through a file descriptor.
-/* Array of file descriptors opened. If it points to a directory, it stores
- info about this directory; otherwise it stores an errno value of ENOTDIR. */
+ FIXME: On mingw, this would be possible to enforce if we were to
+ also open a HANDLE to each directory currently visited by a file
+ descriptor, since mingw refuses to rename any in-use file system
+ object. */
+
+/* Array of file descriptors opened. If REPLACE_OPEN_DIRECTORY or if it points
+ to a directory, it stores info about this directory. */
typedef struct
{
char *name; /* Absolute name of the directory, or NULL. */
- int saved_errno; /* If name == NULL: The error code describing the failure
- reason. */
+ /* FIXME - add a DIR* member to make dirfd possible on mingw? */
} dir_info_t;
static dir_info_t *dirs;
static size_t dirs_allocated;
-/* Try to ensure dirs has enough room for a slot at index fd. */
-static void
+/* Try to ensure dirs has enough room for a slot at index fd; free any
+ contents already in that slot. Return false and set errno to
+ ENOMEM on allocation failure. */
+static bool
ensure_dirs_slot (size_t fd)
{
- if (fd >= dirs_allocated)
+ if (fd < dirs_allocated)
+ free (dirs[fd].name);
+ else
{
size_t new_allocated;
dir_info_t *new_dirs;
- size_t i;
new_allocated = 2 * dirs_allocated + 1;
if (new_allocated <= fd)
- new_allocated = fd + 1;
+ new_allocated = fd + 1;
new_dirs =
- (dirs != NULL
- ? (dir_info_t *) realloc (dirs, new_allocated * sizeof (dir_info_t))
- : (dir_info_t *) malloc (new_allocated * sizeof (dir_info_t)));
- if (new_dirs != NULL)
- {
- for (i = dirs_allocated; i < new_allocated; i++)
- {
- new_dirs[i].name = NULL;
- new_dirs[i].saved_errno = ENOTDIR;
- }
- dirs = new_dirs;
- dirs_allocated = new_allocated;
- }
+ (dirs != NULL
+ ? (dir_info_t *) realloc (dirs, new_allocated * sizeof *dirs)
+ : (dir_info_t *) malloc (new_allocated * sizeof *dirs));
+ if (new_dirs == NULL)
+ return false;
+ memset (new_dirs + dirs_allocated, 0,
+ (new_allocated - dirs_allocated) * sizeof *dirs);
+ dirs = new_dirs;
+ dirs_allocated = new_allocated;
}
+ return true;
}
-/* Override open() and close(), to keep track of the open file descriptors. */
-
-int
-close (int fd)
-#undef close
+/* Return an absolute name of DIR in malloc'd storage. */
+static char *
+get_name (char const *dir)
{
- int retval = close (fd);
+ char *cwd;
+ char *result;
+ int saved_errno;
+
+ if (IS_ABSOLUTE_FILE_NAME (dir))
+ return strdup (dir);
+
+ /* We often encounter "."; treat it as a special case. */
+ cwd = getcwd (NULL, 0);
+ if (!cwd || (dir[0] == '.' && dir[1] == '\0'))
+ return cwd;
+
+ result = mfile_name_concat (cwd, dir, NULL);
+ saved_errno = errno;
+ free (cwd);
+ errno = saved_errno;
+ return result;
+}
- if (retval >= 0 && fd >= 0 && fd < dirs_allocated)
+/* Hook into the gnulib replacements for open() and close() to keep track
+ of the open file descriptors. */
+
+/* Close FD, cleaning up any fd to name mapping if fd was visiting a
+ directory. */
+void
+_gl_unregister_fd (int fd)
+{
+ if (fd >= 0 && fd < dirs_allocated)
{
- if (dirs[fd].name != NULL)
- free (dirs[fd].name);
+ free (dirs[fd].name);
dirs[fd].name = NULL;
- dirs[fd].saved_errno = ENOTDIR;
}
- return retval;
}
+/* Mark FD as visiting FILENAME. FD must be non-negative, and refer
+ to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero,
+ this should only be called if FD is visiting a directory. Close FD
+ and return -1 if there is insufficient memory to track the
+ directory name; otherwise return FD. */
int
-open (const char *filename, int flags, ...)
-#undef open
+_gl_register_fd (int fd, const char *filename)
{
- mode_t mode;
- int fd;
struct stat statbuf;
- mode = 0;
- if (flags & O_CREAT)
- {
- va_list arg;
- va_start (arg, flags);
-
- /* If mode_t is narrower than int, use the promoted type (int),
- not mode_t. Use sizeof to guess whether mode_t is narrower;
- we don't know of any practical counterexamples. */
- mode = (sizeof (mode_t) < sizeof (int)
- ? va_arg (arg, int)
- : va_arg (arg, mode_t));
-
- va_end (arg);
- }
- fd = open (filename, flags, mode);
- if (fd >= 0)
+ assert (0 <= fd);
+ if (REPLACE_OPEN_DIRECTORY
+ || (fstat (fd, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)))
{
- ensure_dirs_slot (fd);
- if (fd < dirs_allocated
- && fstat (fd, &statbuf) >= 0 && S_ISDIR (statbuf.st_mode))
- {
- dirs[fd].name = canonicalize_file_name (filename);
- if (dirs[fd].name == NULL)
- dirs[fd].saved_errno = errno;
- }
+ if (!ensure_dirs_slot (fd)
+ || (dirs[fd].name = get_name (filename)) == NULL)
+ {
+ int saved_errno = errno;
+ close (fd);
+ errno = saved_errno;
+ return -1;
+ }
}
return fd;
}
-/* Override opendir() and closedir(), to keep track of the open file
- descriptors. Needed because there is a function dirfd(). */
-
+/* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3,
+ and fcntl. Both arguments must be valid and distinct file
+ descriptors. Close NEWFD and return -1 if OLDFD is tracking a
+ directory, but there is insufficient memory to track the same
+ directory in NEWFD; otherwise return NEWFD. */
int
-closedir (DIR *dp)
-#undef closedir
+_gl_register_dup (int oldfd, int newfd)
{
- int fd = dirfd (dp);
- int retval = closedir (dp);
-
- if (retval >= 0 && fd >= 0 && fd < dirs_allocated)
+ assert (0 <= oldfd && 0 <= newfd && oldfd != newfd);
+ if (oldfd < dirs_allocated && dirs[oldfd].name)
{
- if (dirs[fd].name != NULL)
- free (dirs[fd].name);
- dirs[fd].name = NULL;
- dirs[fd].saved_errno = ENOTDIR;
+ /* Duplicated a directory; must ensure newfd is allocated. */
+ if (!ensure_dirs_slot (newfd)
+ || (dirs[newfd].name = strdup (dirs[oldfd].name)) == NULL)
+ {
+ int saved_errno = errno;
+ close (newfd);
+ errno = saved_errno;
+ newfd = -1;
+ }
}
- return retval;
-}
-
-DIR *
-opendir (const char *filename)
-#undef opendir
-{
- DIR *dp;
-
- dp = opendir (filename);
- if (dp != NULL)
- {
- int fd = dirfd (dp);
- if (fd >= 0)
- {
- ensure_dirs_slot (fd);
- if (fd < dirs_allocated)
- {
- dirs[fd].name = canonicalize_file_name (filename);
- if (dirs[fd].name == NULL)
- dirs[fd].saved_errno = errno;
- }
- }
- }
- return dp;
-}
-
-/* Override dup() and dup2(), to keep track of open file descriptors. */
-
-int
-dup (int oldfd)
-#undef dup
-{
- int newfd = dup (oldfd);
-
- if (oldfd >= 0 && newfd >= 0)
+ else if (newfd < dirs_allocated)
{
- ensure_dirs_slot (newfd);
- if (newfd < dirs_allocated)
- {
- if (oldfd < dirs_allocated)
- {
- if (dirs[oldfd].name != NULL)
- {
- dirs[newfd].name = strdup (dirs[oldfd].name);
- if (dirs[newfd].name == NULL)
- dirs[newfd].saved_errno = ENOMEM;
- }
- else
- {
- dirs[newfd].name = NULL;
- dirs[newfd].saved_errno = dirs[oldfd].saved_errno;
- }
- }
- else
- {
- dirs[newfd].name = NULL;
- dirs[newfd].saved_errno = ENOMEM;
- }
- }
+ /* Duplicated a non-directory; ensure newfd is cleared. */
+ free (dirs[newfd].name);
+ dirs[newfd].name = NULL;
}
return newfd;
}
-int
-dup2 (int oldfd, int newfd)
-#undef dup2
+/* If FD is currently visiting a directory, then return the name of
+ that directory. Otherwise, return NULL and set errno. */
+const char *
+_gl_directory_name (int fd)
{
- int retval = dup2 (oldfd, newfd);
-
- if (retval >= 0 && oldfd >= 0 && newfd >= 0 && newfd != oldfd)
+ if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
+ return dirs[fd].name;
+ /* At this point, fd is either invalid, or open but not a directory.
+ If dup2 fails, errno is correctly EBADF. */
+ if (0 <= fd)
{
- ensure_dirs_slot (newfd);
- if (newfd < dirs_allocated)
- {
- if (oldfd < dirs_allocated)
- {
- if (dirs[oldfd].name != NULL)
- {
- dirs[newfd].name = strdup (dirs[oldfd].name);
- if (dirs[newfd].name == NULL)
- dirs[newfd].saved_errno = ENOMEM;
- }
- else
- {
- dirs[newfd].name = NULL;
- dirs[newfd].saved_errno = dirs[oldfd].saved_errno;
- }
- }
- else
- {
- dirs[newfd].name = NULL;
- dirs[newfd].saved_errno = ENOMEM;
- }
- }
+ if (dup2 (fd, fd) == fd)
+ errno = ENOTDIR;
}
- return retval;
+ else
+ errno = EBADF;
+ return NULL;
}
+
/* Implement fchdir() in terms of chdir(). */
int
fchdir (int fd)
{
- if (fd >= 0)
- {
- if (fd < dirs_allocated)
- {
- if (dirs[fd].name != NULL)
- return chdir (dirs[fd].name);
- else
- {
- errno = dirs[fd].saved_errno;
- return -1;
- }
- }
- else
- {
- errno = ENOMEM;
- return -1;
- }
- }
- else
- {
- errno = EBADF;
- return -1;
- }
+ const char *name = _gl_directory_name (fd);
+ return name ? chdir (name) : -1;
}
projects / gnulib.git / blobdiff