| /* Determine current working directory. Linux version. |
| Copyright (C) 1997-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <limits.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <sys/param.h> |
| |
| #include <sysdep.h> |
| #include <sys/syscall.h> |
| |
| |
| /* If we compile the file for use in ld.so we don't need the feature |
| that getcwd() allocates the buffers itself. */ |
| #if IS_IN (rtld) |
| # define NO_ALLOCATION 1 |
| #endif |
| |
| |
| /* The "proc" filesystem provides an easy method to retrieve the value. |
| For each process, the corresponding directory contains a symbolic link |
| named `cwd'. Reading the content of this link immediate gives us the |
| information. But we have to take care for systems which do not have |
| the proc filesystem mounted. Use the POSIX implementation in this case. */ |
| static char *generic_getcwd (char *buf, size_t size); |
| |
| char * |
| __getcwd (char *buf, size_t size) |
| { |
| char *path; |
| char *result; |
| |
| #ifndef NO_ALLOCATION |
| size_t alloc_size = size; |
| if (size == 0) |
| { |
| if (buf != NULL) |
| { |
| __set_errno (EINVAL); |
| return NULL; |
| } |
| |
| alloc_size = MAX (PATH_MAX, __getpagesize ()); |
| } |
| |
| if (buf == NULL) |
| { |
| path = malloc (alloc_size); |
| if (path == NULL) |
| return NULL; |
| } |
| else |
| #else |
| # define alloc_size size |
| #endif |
| path = buf; |
| |
| int retval; |
| |
| retval = INLINE_SYSCALL (getcwd, 2, path, alloc_size); |
| if (retval > 0 && path[0] == '/') |
| { |
| #ifndef NO_ALLOCATION |
| if (buf == NULL && size == 0) |
| /* Ensure that the buffer is only as large as necessary. */ |
| buf = realloc (path, (size_t) retval); |
| |
| if (buf == NULL) |
| /* Either buf was NULL all along, or `realloc' failed but |
| we still have the original string. */ |
| buf = path; |
| #endif |
| |
| return buf; |
| } |
| |
| /* The system call either cannot handle paths longer than a page |
| or can succeed without returning an absolute path. Just use the |
| generic implementation right away. */ |
| if (retval >= 0 || errno == ENAMETOOLONG) |
| { |
| #ifndef NO_ALLOCATION |
| if (buf == NULL && size == 0) |
| { |
| free (path); |
| path = NULL; |
| } |
| #endif |
| |
| result = generic_getcwd (path, size); |
| |
| #ifndef NO_ALLOCATION |
| if (result == NULL && buf == NULL && size != 0) |
| free (path); |
| #endif |
| |
| return result; |
| } |
| |
| /* It should never happen that the `getcwd' syscall failed because |
| the buffer is too small if we allocated the buffer ourselves |
| large enough. */ |
| assert (errno != ERANGE || buf != NULL || size != 0); |
| |
| #ifndef NO_ALLOCATION |
| if (buf == NULL) |
| free (path); |
| #endif |
| |
| return NULL; |
| } |
| weak_alias (__getcwd, getcwd) |
| |
| /* Get the code for the generic version. */ |
| #define GETCWD_RETURN_TYPE static char * |
| #define __getcwd generic_getcwd |
| #include <sysdeps/posix/getcwd.c> |