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fe0ec73e | 1 | /* Determine current working directory. Linux version. |
2b778ceb | 2 | Copyright (C) 1997-2021 Free Software Foundation, Inc. |
fe0ec73e UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
fe0ec73e UD |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
fe0ec73e | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
fe0ec73e | 19 | |
958f238f | 20 | #include <assert.h> |
fe0ec73e UD |
21 | #include <errno.h> |
22 | #include <limits.h> | |
23 | #include <stdlib.h> | |
24 | #include <unistd.h> | |
df6a4a4a | 25 | #include <sys/param.h> |
0dee6738 UD |
26 | |
27 | #include <sysdep.h> | |
63bda0c1 | 28 | #include <sys/syscall.h> |
fe0ec73e | 29 | |
958f238f | 30 | |
8d04a97c UD |
31 | /* If we compile the file for use in ld.so we don't need the feature |
32 | that getcwd() allocates the buffers itself. */ | |
a3848485 | 33 | #if IS_IN (rtld) |
8d04a97c UD |
34 | # define NO_ALLOCATION 1 |
35 | #endif | |
36 | ||
37 | ||
7fb90fb8 UD |
38 | /* The "proc" filesystem provides an easy method to retrieve the value. |
39 | For each process, the corresponding directory contains a symbolic link | |
40 | named `cwd'. Reading the content of this link immediate gives us the | |
41 | information. But we have to take care for systems which do not have | |
42 | the proc filesystem mounted. Use the POSIX implementation in this case. */ | |
fcdbd910 AZ |
43 | |
44 | /* Get the code for the generic version. */ | |
45 | #define GETCWD_RETURN_TYPE static char * | |
46 | #include <sysdeps/posix/getcwd.c> | |
7fb90fb8 | 47 | |
fe0ec73e UD |
48 | char * |
49 | __getcwd (char *buf, size_t size) | |
50 | { | |
fe0ec73e | 51 | char *path; |
fe0ec73e | 52 | char *result; |
6973fc01 | 53 | |
8d04a97c UD |
54 | #ifndef NO_ALLOCATION |
55 | size_t alloc_size = size; | |
a2b3aa73 | 56 | if (size == 0) |
fe0ec73e UD |
57 | { |
58 | if (buf != NULL) | |
59 | { | |
60 | __set_errno (EINVAL); | |
61 | return NULL; | |
62 | } | |
63 | ||
6c7a5753 | 64 | alloc_size = MAX (PATH_MAX, __getpagesize ()); |
fe0ec73e UD |
65 | } |
66 | ||
8d04a97c | 67 | if (buf == NULL) |
fe0ec73e | 68 | { |
6973fc01 | 69 | path = malloc (alloc_size); |
fe0ec73e UD |
70 | if (path == NULL) |
71 | return NULL; | |
72 | } | |
8d04a97c UD |
73 | else |
74 | #else | |
75 | # define alloc_size size | |
76 | #endif | |
77 | path = buf; | |
fe0ec73e | 78 | |
ffb7875d | 79 | int retval; |
7fb90fb8 | 80 | |
6277fdab | 81 | retval = INLINE_SYSCALL (getcwd, 2, path, alloc_size); |
52a713fd | 82 | if (retval > 0 && path[0] == '/') |
ffb7875d JM |
83 | { |
84 | #ifndef NO_ALLOCATION | |
85 | if (buf == NULL && size == 0) | |
86 | /* Ensure that the buffer is only as large as necessary. */ | |
87 | buf = realloc (path, (size_t) retval); | |
958f238f UD |
88 | |
89 | if (buf == NULL) | |
ffb7875d JM |
90 | /* Either buf was NULL all along, or `realloc' failed but |
91 | we still have the original string. */ | |
92 | buf = path; | |
93 | #endif | |
958f238f | 94 | |
ffb7875d | 95 | return buf; |
63bda0c1 | 96 | } |
63bda0c1 | 97 | |
52a713fd DL |
98 | /* The system call either cannot handle paths longer than a page |
99 | or can succeed without returning an absolute path. Just use the | |
ffb7875d | 100 | generic implementation right away. */ |
52a713fd | 101 | if (retval >= 0 || errno == ENAMETOOLONG) |
fe0ec73e | 102 | { |
8d04a97c | 103 | #ifndef NO_ALLOCATION |
ffb7875d JM |
104 | if (buf == NULL && size == 0) |
105 | { | |
106 | free (path); | |
107 | path = NULL; | |
fe0ec73e | 108 | } |
958f238f | 109 | #endif |
fe0ec73e | 110 | |
fcdbd910 | 111 | result = __getcwd_generic (path, size); |
6973fc01 | 112 | |
8d04a97c | 113 | #ifndef NO_ALLOCATION |
ffb7875d JM |
114 | if (result == NULL && buf == NULL && size != 0) |
115 | free (path); | |
8d04a97c | 116 | #endif |
6973fc01 | 117 | |
ffb7875d JM |
118 | return result; |
119 | } | |
120 | ||
121 | /* It should never happen that the `getcwd' syscall failed because | |
122 | the buffer is too small if we allocated the buffer ourselves | |
123 | large enough. */ | |
124 | assert (errno != ERANGE || buf != NULL || size != 0); | |
fe0ec73e | 125 | |
8d04a97c | 126 | #ifndef NO_ALLOCATION |
ffb7875d | 127 | if (buf == NULL) |
fe0ec73e | 128 | free (path); |
8d04a97c | 129 | #endif |
fe0ec73e | 130 | |
ffb7875d | 131 | return NULL; |
fe0ec73e | 132 | } |
db25266c | 133 | libc_hidden_def (__getcwd) |
fe0ec73e | 134 | weak_alias (__getcwd, getcwd) |