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bf5a7247 | 1 | .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) |
fea681da | 2 | .\" |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
fea681da MK |
4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
c13182ef | 12 | .\" |
fea681da MK |
13 | .\" Since the Linux kernel and libraries are constantly changing, this |
14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
15 | .\" responsibility for errors or omissions, or for damages resulting from | |
16 | .\" the use of the information contained herein. The author(s) may not | |
17 | .\" have taken the same level of care in the production of this manual, | |
18 | .\" which is licensed free of charge, as they might when working | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
fea681da MK |
21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
c08df37a | 24 | .\" |
fea681da MK |
25 | .\" Modified Wed Jul 21 22:35:42 1993 by Rik Faith (faith@cs.unc.edu) |
26 | .\" Modified 18 Mar 1996 by Martin Schulze (joey@infodrom.north.de): | |
27 | .\" Corrected description of getwd(). | |
28 | .\" Modified Sat Aug 21 12:32:12 MET 1999 by aeb - applied fix by aj | |
29 | .\" Modified Mon Dec 11 13:32:51 MET 2000 by aeb | |
30 | .\" Modified Thu Apr 22 03:49:15 CEST 2002 by Roger Luethi <rl@hellgate.ch> | |
31 | .\" | |
97986708 | 32 | .TH GETCWD 3 2016-03-15 "GNU" "Linux Programmer's Manual" |
fea681da | 33 | .SH NAME |
f68512e9 | 34 | getcwd, getwd, get_current_dir_name \- get current working directory |
fea681da MK |
35 | .SH SYNOPSIS |
36 | .nf | |
37 | .B #include <unistd.h> | |
38 | .sp | |
39 | .BI "char *getcwd(char *" buf ", size_t " size ); | |
ecad088b | 40 | .sp |
fea681da | 41 | .BI "char *getwd(char *" buf ); |
ecad088b | 42 | .sp |
ecad088b | 43 | .B "char *get_current_dir_name(void);" |
fea681da | 44 | .fi |
cc4615cc MK |
45 | .sp |
46 | .in -4n | |
47 | Feature Test Macro Requirements for glibc (see | |
48 | .BR feature_test_macros (7)): | |
a74ec77e | 49 | .sp |
cc4615cc | 50 | .in |
cc4615cc | 51 | .BR get_current_dir_name (): |
a74ec77e | 52 | .RS |
cc4615cc | 53 | _GNU_SOURCE |
a74ec77e | 54 | .RE |
a89b9a38 MK |
55 | .sp |
56 | .BR getwd (): | |
57 | .ad l | |
58 | .RS 4 | |
59 | .PD 0 | |
60 | .TP 4 | |
61 | Since glibc 2.12: | |
62 | .nf | |
6e0869f7 MK |
63 | (_XOPEN_SOURCE\ >=\ 500) && ! (_POSIX_C_SOURCE\ >=\ 200809L) |
64 | || /* Glibc since 2.19: */ _DEFAULT_SOURCE | |
65 | || /* Glibc versions <= 2.19: */ _BSD_SOURCE | |
a89b9a38 MK |
66 | .TP 4 |
67 | .fi | |
68 | Before glibc 2.12: | |
cf7fa0a1 MK |
69 | _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 |
70 | .\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED | |
a89b9a38 MK |
71 | .PD |
72 | .RE | |
73 | .ad b | |
fea681da | 74 | .SH DESCRIPTION |
c359e37d MK |
75 | These functions return a null-terminated string containing an |
76 | absolute pathname that is the current working directory of | |
77 | the calling process. | |
78 | The pathname is returned as the function result and via the argument | |
79 | .IR buf , | |
80 | if present. | |
81 | ||
a2ac97c7 | 82 | If the current directory is not below the root directory of the current |
2b1f1a35 | 83 | process (e.g., because the process set a new filesystem root using |
a2ac97c7 | 84 | .BR chroot (2) |
de0dd427 | 85 | without changing its current directory into the new root), |
2b1f1a35 MK |
86 | then, since Linux 2.6.36, |
87 | .\" commit 8df9d1a4142311c084ffeeacb67cd34d190eff74 | |
de0dd427 MK |
88 | the returned path will be prefixed with the string "(unreachable)". |
89 | Such behavior can also be caused by an unprivileged user by changing | |
90 | the current directory into another mount namespace. | |
a2ac97c7 JH |
91 | When dealing with paths from untrusted sources, callers of these |
92 | functions should consider checking whether the returned path starts | |
93 | with '/' or '(' to avoid misinterpreting an unreachable path | |
94 | as a relative path. | |
95 | ||
fea681da MK |
96 | The |
97 | .BR getcwd () | |
98 | function copies an absolute pathname of the current working directory | |
99 | to the array pointed to by | |
100 | .IR buf , | |
101 | which is of length | |
102 | .IR size . | |
103 | .PP | |
c359e37d MK |
104 | If the length of the absolute pathname of the current working directory, |
105 | including the terminating null byte, exceeds | |
fea681da | 106 | .I size |
c359e37d | 107 | bytes, NULL is returned, and |
fea681da MK |
108 | .I errno |
109 | is set to | |
110 | .BR ERANGE ; | |
111 | an application should check for this error, and allocate a larger | |
112 | buffer if necessary. | |
113 | .PP | |
acd67de4 | 114 | As an extension to the POSIX.1-2001 standard, glibc's |
63aa9df0 | 115 | .BR getcwd () |
fea681da | 116 | allocates the buffer dynamically using |
fb186734 | 117 | .BR malloc (3) |
fea681da MK |
118 | if |
119 | .I buf | |
c359e37d | 120 | is NULL. |
8478ee02 | 121 | In this case, the allocated buffer has the length |
fea681da MK |
122 | .I size |
123 | unless | |
124 | .I size | |
125 | is zero, when | |
126 | .I buf | |
c13182ef | 127 | is allocated as big as necessary. |
c359e37d | 128 | The caller should |
fb186734 | 129 | .BR free (3) |
c359e37d | 130 | the returned buffer. |
fea681da | 131 | |
51d0a7e9 | 132 | .BR get_current_dir_name () |
ecad088b | 133 | will |
fea681da | 134 | .BR malloc (3) |
c359e37d MK |
135 | an array big enough to hold the absolute pathname of |
136 | the current working directory. | |
c13182ef | 137 | If the environment |
fea681da MK |
138 | variable |
139 | .B PWD | |
140 | is set, and its value is correct, then that value will be returned. | |
c359e37d MK |
141 | The caller should |
142 | .BR free (3) | |
143 | the returned buffer. | |
fea681da | 144 | |
7847d5cd | 145 | .BR getwd () |
ecad088b | 146 | does not |
fea681da | 147 | .BR malloc (3) |
c13182ef | 148 | any memory. |
ecad088b | 149 | The |
fea681da MK |
150 | .I buf |
151 | argument should be a pointer to an array at least | |
152 | .B PATH_MAX | |
153 | bytes long. | |
c359e37d MK |
154 | If the length of the absolute pathname of the current working directory, |
155 | including the terminating null byte, exceeds | |
fea681da | 156 | .B PATH_MAX |
c359e37d MK |
157 | bytes, NULL is returned, and |
158 | .I errno | |
159 | is set to | |
160 | .BR ENAMETOOLONG . | |
b4338c3f MK |
161 | (Note that on some systems, |
162 | .B PATH_MAX | |
e8f4a1c9 | 163 | may not be a compile-time constant; |
9ee4a2b6 | 164 | furthermore, its value may depend on the filesystem, see |
b4338c3f | 165 | .BR pathconf (3).) |
ecad088b | 166 | For portability and security reasons, use of |
e511ffb6 | 167 | .BR getwd () |
fea681da | 168 | is deprecated. |
47297adb | 169 | .SH RETURN VALUE |
c359e37d MK |
170 | On success, these functions return a pointer to a string containing |
171 | the pathname of the current working directory. | |
172 | In the case | |
173 | .BR getcwd () | |
174 | and | |
175 | .BR getwd () | |
176 | this is the same value as | |
fe48639f | 177 | .IR buf . |
c359e37d MK |
178 | |
179 | On failure, these functions return NULL, and | |
fea681da | 180 | .I errno |
c359e37d | 181 | is set to indicate the error. |
c13182ef | 182 | The contents of the array pointed to by |
0daa9e92 | 183 | .I buf |
c359e37d | 184 | are undefined on error. |
fea681da MK |
185 | .SH ERRORS |
186 | .TP | |
187 | .B EACCES | |
c13182ef | 188 | Permission to read or search a component of the filename was denied. |
fea681da MK |
189 | .TP |
190 | .B EFAULT | |
0daa9e92 | 191 | .I buf |
fea681da MK |
192 | points to a bad address. |
193 | .TP | |
194 | .B EINVAL | |
c13182ef | 195 | The |
0daa9e92 | 196 | .I size |
fea681da | 197 | argument is zero and |
0daa9e92 | 198 | .I buf |
b437fdd9 | 199 | is not a null pointer. |
fea681da | 200 | .TP |
83685d1e | 201 | .B EINVAL |
c359e37d MK |
202 | .BR getwd (): |
203 | .I buf | |
204 | is NULL. | |
205 | .TP | |
83685d1e | 206 | .B ENAMETOOLONG |
c359e37d MK |
207 | .BR getwd (): |
208 | The size of the null-terminated absolute pathname string exceeds | |
209 | .B PATH_MAX | |
210 | bytes. | |
211 | .TP | |
28e8ce31 MK |
212 | .B ENOMEM |
213 | Out of memory. | |
214 | .TP | |
fea681da MK |
215 | .B ENOENT |
216 | The current working directory has been unlinked. | |
217 | .TP | |
218 | .B ERANGE | |
219 | The | |
0daa9e92 | 220 | .I size |