diff options
Diffstat (limited to 'libgnu/getcwd.c')
| -rw-r--r-- | libgnu/getcwd.c | 446 |
1 files changed, 0 insertions, 446 deletions
diff --git a/libgnu/getcwd.c b/libgnu/getcwd.c deleted file mode 100644 index d91cf377..00000000 --- a/libgnu/getcwd.c +++ /dev/null @@ -1,446 +0,0 @@ -/* Copyright (C) 1991-1999, 2004-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - 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 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 - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - 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, see <http://www.gnu.org/licenses/>. */ - -#if !_LIBC -# include <config.h> -# include <unistd.h> -#endif - -#include <errno.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <stdbool.h> -#include <stddef.h> - -#include <fcntl.h> /* For AT_FDCWD on Solaris 9. */ - -/* If this host provides the openat function or if we're using the - gnulib replacement function with a native fdopendir, then enable - code below to make getcwd more efficient and robust. */ -#if defined HAVE_OPENAT || (defined GNULIB_OPENAT && defined HAVE_FDOPENDIR) -# define HAVE_OPENAT_SUPPORT 1 -#else -# define HAVE_OPENAT_SUPPORT 0 -#endif - -#ifndef __set_errno -# define __set_errno(val) (errno = (val)) -#endif - -#include <dirent.h> -#ifndef _D_EXACT_NAMLEN -# define _D_EXACT_NAMLEN(d) strlen ((d)->d_name) -#endif -#ifndef _D_ALLOC_NAMLEN -# define _D_ALLOC_NAMLEN(d) (_D_EXACT_NAMLEN (d) + 1) -#endif - -#include <unistd.h> -#include <stdlib.h> -#include <string.h> - -#if _LIBC -# ifndef mempcpy -# define mempcpy __mempcpy -# endif -#endif - -#ifndef MAX -# define MAX(a, b) ((a) < (b) ? (b) : (a)) -#endif -#ifndef MIN -# define MIN(a, b) ((a) < (b) ? (a) : (b)) -#endif - -#include "pathmax.h" - -/* In this file, PATH_MAX only serves as a threshold for choosing among two - algorithms. */ -#ifndef PATH_MAX -# define PATH_MAX 8192 -#endif - -#if D_INO_IN_DIRENT -# define MATCHING_INO(dp, ino) ((dp)->d_ino == (ino)) -#else -# define MATCHING_INO(dp, ino) true -#endif - -#if !_LIBC -# define __getcwd rpl_getcwd -# define __lstat lstat -# define __closedir closedir -# define __opendir opendir -# define __readdir readdir -#endif - -/* The results of opendir() in this file are not used with dirfd and fchdir, - and we do not leak fds to any single-threaded code that could use stdio, - therefore save some unnecessary recursion in fchdir.c. - FIXME - if the kernel ever adds support for multi-thread safety for - avoiding standard fds, then we should use opendir_safer and - openat_safer. */ -#ifdef GNULIB_defined_opendir -# undef opendir -#endif -#ifdef GNULIB_defined_closedir -# undef closedir -#endif - -/* Get the name of the current working directory, and put it in SIZE - bytes of BUF. Returns NULL if the directory couldn't be determined or - SIZE was too small. If successful, returns BUF. In GNU, if BUF is - NULL, an array is allocated with 'malloc'; the array is SIZE bytes long, - unless SIZE == 0, in which case it is as big as necessary. */ - -char * -__getcwd (char *buf, size_t size) -{ - /* Lengths of big file name components and entire file names, and a - deep level of file name nesting. These numbers are not upper - bounds; they are merely large values suitable for initial - allocations, designed to be large enough for most real-world - uses. */ - enum - { - BIG_FILE_NAME_COMPONENT_LENGTH = 255, - BIG_FILE_NAME_LENGTH = MIN (4095, PATH_MAX - 1), - DEEP_NESTING = 100 - }; - -#if HAVE_OPENAT_SUPPORT - int fd = AT_FDCWD; - bool fd_needs_closing = false; -#else - char dots[DEEP_NESTING * sizeof ".." + BIG_FILE_NAME_COMPONENT_LENGTH + 1]; - char *dotlist = dots; - size_t dotsize = sizeof dots; - size_t dotlen = 0; -#endif - DIR *dirstream = NULL; - dev_t rootdev, thisdev; - ino_t rootino, thisino; - char *dir; - register char *dirp; - struct stat st; - size_t allocated = size; - size_t used; - -#if HAVE_MINIMALLY_WORKING_GETCWD - /* If AT_FDCWD is not defined, the algorithm below is O(N**2) and - this is much slower than the system getcwd (at least on - GNU/Linux). So trust the system getcwd's results unless they - look suspicious. - - Use the system getcwd even if we have openat support, since the - system getcwd works even when a parent is unreadable, while the - openat-based approach does not. - - But on AIX 5.1..7.1, the system getcwd is not even minimally - working: If the current directory name is slightly longer than - PATH_MAX, it omits the first directory component and returns - this wrong result with errno = 0. */ - -# undef getcwd - dir = getcwd (buf, size); - if (dir || (size && errno == ERANGE)) - return dir; - - /* Solaris getcwd (NULL, 0) fails with errno == EINVAL, but it has - internal magic that lets it work even if an ancestor directory is - inaccessible, which is better in many cases. So in this case try - again with a buffer that's almost always big enough. */ - if (errno == EINVAL && buf == NULL && size == 0) - { - char big_buffer[BIG_FILE_NAME_LENGTH + 1]; - dir = getcwd (big_buffer, sizeof big_buffer); - if (dir) - return strdup (dir); - } - -# if HAVE_PARTLY_WORKING_GETCWD - /* The system getcwd works, except it sometimes fails when it - shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT. */ - if (errno != ERANGE && errno != ENAMETOOLONG && errno != ENOENT) - return NULL; -# endif -#endif - - if (size == 0) - { - if (buf != NULL) - { - __set_errno (EINVAL); - return NULL; - } - - allocated = BIG_FILE_NAME_LENGTH + 1; - } - - if (buf == NULL) - { - dir = malloc (allocated); - if (dir == NULL) - return NULL; - } - else - dir = buf; - - dirp = dir + allocated; - *--dirp = '\0'; - - if (__lstat (".", &st) < 0) - goto lose; - thisdev = st.st_dev; - thisino = st.st_ino; - - if (__lstat ("/", &st) < 0) - goto lose; - rootdev = st.st_dev; - rootino = st.st_ino; - - while (!(thisdev == rootdev && thisino == rootino)) - { - struct dirent *d; - dev_t dotdev; - ino_t dotino; - bool mount_point; - int parent_status; - size_t dirroom; - size_t namlen; - bool use_d_ino = true; - - /* Look at the parent directory. */ -#if HAVE_OPENAT_SUPPORT - fd = openat (fd, "..", O_RDONLY); - if (fd < 0) - goto lose; - fd_needs_closing = true; - parent_status = fstat (fd, &st); -#else - dotlist[dotlen++] = '.'; - dotlist[dotlen++] = '.'; - dotlist[dotlen] = '\0'; - parent_status = __lstat (dotlist, &st); -#endif - if (parent_status != 0) - goto lose; - - if (dirstream && __closedir (dirstream) != 0) - { - dirstream = NULL; - goto lose; - } - - /* Figure out if this directory is a mount point. */ - dotdev = st.st_dev; - dotino = st.st_ino; - mount_point = dotdev != thisdev; - - /* Search for the last directory. */ -#if HAVE_OPENAT_SUPPORT - dirstream = fdopendir (fd); - if (dirstream == NULL) - goto lose; - fd_needs_closing = false; -#else - dirstream = __opendir (dotlist); - if (dirstream == NULL) - goto lose; - dotlist[dotlen++] = '/'; -#endif - for (;;) - { - /* Clear errno to distinguish EOF from error if readdir returns - NULL. */ - __set_errno (0); - d = __readdir (dirstream); - - /* When we've iterated through all directory entries without finding - one with a matching d_ino, rewind the stream and consider each - name again, but this time, using lstat. This is necessary in a - chroot on at least one system (glibc-2.3.6 + linux 2.6.12), where - .., ../.., ../../.., etc. all had the same device number, yet the - d_ino values for entries in / did not match those obtained - via lstat. */ - if (d == NULL && errno == 0 && use_d_ino) - { - use_d_ino = false; - rewinddir (dirstream); - d = __readdir (dirstream); - } - - if (d == NULL) - { - if (errno == 0) - /* EOF on dirstream, which can mean e.g., that the current - directory has been removed. */ - __set_errno (ENOENT); - goto lose; - } - if (d->d_name[0] == '.' && - (d->d_name[1] == '\0' || - (d->d_name[1] == '.' && d->d_name[2] == '\0'))) - continue; - - if (use_d_ino) - { - bool match = (MATCHING_INO (d, thisino) || mount_point); - if (! match) - continue; - } - - { - int entry_status; -#if HAVE_OPENAT_SUPPORT - entry_status = fstatat (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW); -#else - /* Compute size needed for this file name, or for the file - name ".." in the same directory, whichever is larger. - Room for ".." might be needed the next time through - the outer loop. */ - size_t name_alloc = _D_ALLOC_NAMLEN (d); - size_t filesize = dotlen + MAX (sizeof "..", name_alloc); - - if (filesize < dotlen) - goto memory_exhausted; - - if (dotsize < filesize) - { - /* My, what a deep directory tree you have, Grandma. */ - size_t newsize = MAX (filesize, dotsize * 2); - size_t i; - if (newsize < dotsize) - goto memory_exhausted; - if (dotlist != dots) - free (dotlist); - dotlist = malloc (newsize); - if (dotlist == NULL) - goto lose; - dotsize = newsize; - - i = 0; - do - { - dotlist[i++] = '.'; - dotlist[i++] = '.'; - dotlist[i++] = '/'; - } - while (i < dotlen); - } - - memcpy (dotlist + dotlen, d->d_name, _D_ALLOC_NAMLEN (d)); - entry_status = __lstat (dotlist, &st); -#endif - /* We don't fail here if we cannot stat() a directory entry. - This can happen when (network) file systems fail. If this - entry is in fact the one we are looking for we will find - out soon as we reach the end of the directory without - having found anything. */ - if (entry_status == 0 && S_ISDIR (st.st_mode) - && st.st_dev == thisdev && st.st_ino == thisino) - break; - } - } - - dirroom = dirp - dir; - namlen = _D_EXACT_NAMLEN (d); - - if (dirroom <= namlen) - { - if (size != 0) - { - __set_errno (ERANGE); - goto lose; - } - else - { - char *tmp; - size_t oldsize = allocated; - - allocated += MAX (allocated, namlen); - if (allocated < oldsize - || ! (tmp = realloc (dir, allocated))) - goto memory_exhausted; - - /* Move current contents up to the end of the buffer. - This is guaranteed to be non-overlapping. */ - dirp = memcpy (tmp + allocated - (oldsize - dirroom), - tmp + dirroom, - oldsize - dirroom); - dir = tmp; - } - } - dirp -= namlen; - memcpy (dirp, d->d_name, namlen); - *--dirp = '/'; - - thisdev = dotdev; - thisino = dotino; - } - - if (dirstream && __closedir (dirstream) != 0) - { - dirstream = NULL; - goto lose; - } - - if (dirp == &dir[allocated - 1]) - *--dirp = '/'; - -#if ! HAVE_OPENAT_SUPPORT - if (dotlist != dots) - free (dotlist); -#endif - - used = dir + allocated - dirp; - memmove (dir, dirp, used); - - if (size == 0) - /* Ensure that the buffer is only as large as necessary. */ - buf = realloc (dir, used); - - if (buf == NULL) - /* Either buf was NULL all along, or 'realloc' failed but - we still have the original string. */ - buf = dir; - - return buf; - - memory_exhausted: - __set_errno (ENOMEM); - lose: - { - int save = errno; - if (dirstream) - __closedir (dirstream); -#if HAVE_OPENAT_SUPPORT - if (fd_needs_closing) - close (fd); -#else - if (dotlist != dots) - free (dotlist); -#endif - if (buf == NULL) - free (dir); - __set_errno (save); - } - return NULL; -} - -#ifdef weak_alias -weak_alias (__getcwd, getcwd) -#endif |