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6ec2e0f5 SDJ |
1 | /* Copyright (C) 2011-2016 Free Software Foundation, Inc. |
2 | This file is part of gnulib. | |
3 | ||
4 | This program is free software: you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 3 of the License, or | |
7 | (at your option) any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
16 | ||
17 | #include <config.h> | |
18 | ||
19 | /* Specification */ | |
20 | #include <unistd.h> | |
21 | ||
22 | #include <errno.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | ||
26 | #if GNULIB_GETCWD | |
27 | /* Favor GPL getcwd.c if both getcwd and getcwd-lgpl modules are in use. */ | |
28 | typedef int dummy; | |
29 | #else | |
30 | ||
31 | /* Get the name of the current working directory, and put it in SIZE | |
32 | bytes of BUF. Returns NULL if the directory couldn't be determined | |
33 | (perhaps because the absolute name was longer than PATH_MAX, or | |
34 | because of missing read/search permissions on parent directories) | |
35 | or SIZE was too small. If successful, returns BUF. If BUF is | |
36 | NULL, an array is allocated with 'malloc'; the array is SIZE bytes | |
37 | long, unless SIZE == 0, in which case it is as big as | |
38 | necessary. */ | |
39 | ||
40 | # undef getcwd | |
41 | char * | |
42 | rpl_getcwd (char *buf, size_t size) | |
43 | { | |
44 | char *ptr; | |
45 | char *result; | |
46 | ||
47 | /* Handle single size operations. */ | |
48 | if (buf) | |
49 | { | |
50 | if (!size) | |
51 | { | |
52 | errno = EINVAL; | |
53 | return NULL; | |
54 | } | |
55 | return getcwd (buf, size); | |
56 | } | |
57 | ||
58 | if (size) | |
59 | { | |
60 | buf = malloc (size); | |
61 | if (!buf) | |
62 | { | |
63 | errno = ENOMEM; | |
64 | return NULL; | |
65 | } | |
66 | result = getcwd (buf, size); | |
67 | if (!result) | |
68 | { | |
69 | int saved_errno = errno; | |
70 | free (buf); | |
71 | errno = saved_errno; | |
72 | } | |
73 | return result; | |
74 | } | |
75 | ||
76 | /* Flexible sizing requested. Avoid over-allocation for the common | |
77 | case of a name that fits within a 4k page, minus some space for | |
78 | local variables, to be sure we don't skip over a guard page. */ | |
79 | { | |
80 | char tmp[4032]; | |
81 | size = sizeof tmp; | |
82 | ptr = getcwd (tmp, size); | |
83 | if (ptr) | |
84 | { | |
85 | result = strdup (ptr); | |
86 | if (!result) | |
87 | errno = ENOMEM; | |
88 | return result; | |
89 | } | |
90 | if (errno != ERANGE) | |
91 | return NULL; | |
92 | } | |
93 | ||
94 | /* My what a large directory name we have. */ | |
95 | do | |
96 | { | |
97 | size <<= 1; | |
98 | ptr = realloc (buf, size); | |
99 | if (ptr == NULL) | |
100 | { | |
101 | free (buf); | |
102 | errno = ENOMEM; | |
103 | return NULL; | |
104 | } | |
105 | buf = ptr; | |
106 | result = getcwd (buf, size); | |
107 | } | |
108 | while (!result && errno == ERANGE); | |
109 | ||
110 | if (!result) | |
111 | { | |
112 | int saved_errno = errno; | |
113 | free (buf); | |
114 | errno = saved_errno; | |
115 | } | |
116 | else | |
117 | { | |
118 | /* Trim to fit, if possible. */ | |
119 | result = realloc (buf, strlen (buf) + 1); | |
120 | if (!result) | |
121 | result = buf; | |
122 | } | |
123 | return result; | |
124 | } | |
125 | ||
126 | #endif |