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-rw-r--r--lib/getcwd.c559
1 files changed, 559 insertions, 0 deletions
diff --git a/lib/getcwd.c b/lib/getcwd.c
new file mode 100644
index 0000000..0530630
--- /dev/null
+++ b/lib/getcwd.c
@@ -0,0 +1,559 @@
+/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ This file 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 file 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 <https://www.gnu.org/licenses/>. */
+
+#if !_LIBC
+# include <config.h>
+# include <stdio.h>
+# include <unistd.h>
+# include "pathmax.h"
+#else
+# define HAVE_OPENAT 1
+# define D_INO_IN_DIRENT 1
+# define HAVE_MSVC_INVALID_PARAMETER_HANDLER 0
+# define HAVE_MINIMALLY_WORKING_GETCWD 0
+#endif
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.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
+
+/* 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 HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# include "msvc-inval.h"
+#endif
+
+#if !_LIBC
+# define GETCWD_RETURN_TYPE char *
+# define __close_nocancel_nostatus close
+# define __getcwd_generic rpl_getcwd
+# undef stat64
+# define stat64 stat
+# define __fstat64 fstat
+# define __fstatat64 fstatat
+# define __lstat64 lstat
+# define __closedir closedir
+# define __opendir opendir
+# define __readdir64 readdir
+# define __fdopendir fdopendir
+# define __openat openat
+# define __rewinddir rewinddir
+# define __openat64 openat
+# define dirent64 dirent
+#else
+# include <not-cancel.h>
+#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
+
+#if defined _WIN32 && !defined __CYGWIN__
+# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+static char *
+getcwd_nothrow (char *buf, size_t size)
+{
+ char *result;
+
+ TRY_MSVC_INVAL
+ {
+ result = _getcwd (buf, size);
+ }
+ CATCH_MSVC_INVAL
+ {
+ result = NULL;
+ errno = ERANGE;
+ }
+ DONE_MSVC_INVAL;
+
+ return result;
+}
+# else
+# define getcwd_nothrow _getcwd
+# endif
+# define getcwd_system getcwd_nothrow
+#else
+# define getcwd_system getcwd
+#endif
+
+/* Get the name of the current working directory, and put it in SIZE
+ bytes of BUF. Returns NULL with errno set 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. */
+
+GETCWD_RETURN_TYPE
+__getcwd_generic (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;
+# if defined __linux__
+ bool proc_fs_not_mounted = false;
+# endif
+#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 stat64 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_system (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_system (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 (__lstat64 (".", &st) < 0)
+ goto lose;
+ thisdev = st.st_dev;
+ thisino = st.st_ino;
+
+ if (__lstat64 ("/", &st) < 0)
+ goto lose;
+ rootdev = st.st_dev;
+ rootino = st.st_ino;
+
+ while (!(thisdev == rootdev && thisino == rootino))
+ {
+ struct dirent64 *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 = __openat64 (fd, "..", O_RDONLY);
+ if (fd < 0)
+ goto lose;
+ fd_needs_closing = true;
+ parent_status = __fstat64 (fd, &st);
+#else
+ dotlist[dotlen++] = '.';
+ dotlist[dotlen++] = '.';
+ dotlist[dotlen] = '\0';
+ parent_status = __lstat64 (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 = __readdir64 (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 = __readdir64 (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 = __fstatat64 (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 = __lstat64 (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 HAVE_OPENAT_SUPPORT
+ /* On some platforms, a system call returns the directory that FD points
+ to. This is useful if some of the ancestor directories of the
+ directory are unreadable, because in this situation the loop that
+ climbs up the ancestor hierarchy runs into an EACCES error.
+ For example, in some Android app, /data/data/com.termux is readable,
+ but /data/data and /data are not. */
+# if defined __linux__
+ /* On Linux, in particular, if /proc is mounted,
+ readlink ("/proc/self/fd/<fd>")
+ returns the directory, if its length is < 4096. (If the length is
+ >= 4096, it fails with error ENAMETOOLONG, even if the buffer that we
+ pass to the readlink function would be large enough.) */
+ if (!proc_fs_not_mounted)
+ {
+ char namebuf[14 + 10 + 1];
+ sprintf (namebuf, "/proc/self/fd/%u", (unsigned int) fd);
+ char linkbuf[4096];
+ ssize_t linklen = readlink (namebuf, linkbuf, sizeof linkbuf);
+ if (linklen < 0)
+ {
+ if (errno != ENAMETOOLONG)
+ /* If this call was not successful, the next one will likely be
+ not successful either. */
+ proc_fs_not_mounted = true;
+ }
+ else
+ {
+ dirroom = dirp - dir;
+ if (dirroom < linklen)
+ {
+ if (size != 0)
+ {
+ __set_errno (ERANGE);
+ goto lose;
+ }
+ else
+ {
+ char *tmp;
+ size_t oldsize = allocated;
+
+ allocated += linklen - dirroom;
+ if (allocated < oldsize
+ || ! (tmp = realloc (dir, allocated)))
+ goto memory_exhausted;
+
+ /* Move current contents up to the end of the buffer. */
+ dirp = memmove (tmp + dirroom + (allocated - oldsize),
+ tmp + dirroom,
+ oldsize - dirroom);
+ dir = tmp;
+ }
+ }
+ dirp -= linklen;
+ memcpy (dirp, linkbuf, linklen);
+ break;
+ }
+ }
+# endif
+#endif
+ }
+
+ 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 = (used < allocated ? realloc (dir, used) : dir);
+
+ 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_nocancel_nostatus (fd);
+#else
+ if (dotlist != dots)
+ free (dotlist);
+#endif
+ if (buf == NULL)
+ free (dir);
+ __set_errno (save);
+ }
+ return NULL;
+}
+
+#if defined _LIBC && !defined GETCWD_RETURN_TYPE
+libc_hidden_def (__getcwd)
+weak_alias (__getcwd, getcwd)
+#endif