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9ff99d22 | 1 | /* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2013 Free Software |
5745a7df PE |
2 | Foundation, Inc. |
3 | ||
4 | NOTE: The canonical source of this file is maintained with the GNU C | |
5 | Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu. | |
6 | ||
7 | This program is free software: you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by the | |
9 | Free Software Foundation; either version 3 of the License, or any | |
10 | later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include <config.h> | |
21 | ||
22 | /* Specification. */ | |
23 | #include <stdlib.h> | |
24 | ||
25 | #include <stddef.h> | |
26 | ||
27 | /* Include errno.h *after* sys/types.h to work around header problems | |
28 | on AIX 3.2.5. */ | |
29 | #include <errno.h> | |
30 | #ifndef __set_errno | |
31 | # define __set_errno(ev) ((errno) = (ev)) | |
32 | #endif | |
33 | ||
34 | #include <string.h> | |
35 | #include <unistd.h> | |
36 | ||
37 | #if _LIBC | |
38 | # if HAVE_GNU_LD | |
39 | # define environ __environ | |
40 | # else | |
41 | extern char **environ; | |
42 | # endif | |
43 | #endif | |
44 | ||
45 | #if _LIBC | |
46 | /* This lock protects against simultaneous modifications of 'environ'. */ | |
47 | # include <bits/libc-lock.h> | |
48 | __libc_lock_define_initialized (static, envlock) | |
49 | # define LOCK __libc_lock_lock (envlock) | |
50 | # define UNLOCK __libc_lock_unlock (envlock) | |
51 | #else | |
52 | # define LOCK | |
53 | # define UNLOCK | |
54 | #endif | |
55 | ||
56 | static int | |
57 | _unsetenv (const char *name) | |
58 | { | |
59 | size_t len; | |
60 | char **ep; | |
61 | ||
62 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) | |
63 | { | |
64 | __set_errno (EINVAL); | |
65 | return -1; | |
66 | } | |
67 | ||
68 | len = strlen (name); | |
69 | ||
70 | LOCK; | |
71 | ||
72 | ep = environ; | |
73 | while (*ep != NULL) | |
74 | if (!strncmp (*ep, name, len) && (*ep)[len] == '=') | |
75 | { | |
76 | /* Found it. Remove this pointer by moving later ones back. */ | |
77 | char **dp = ep; | |
78 | ||
79 | do | |
80 | dp[0] = dp[1]; | |
81 | while (*dp++); | |
82 | /* Continue the loop in case NAME appears again. */ | |
83 | } | |
84 | else | |
85 | ++ep; | |
86 | ||
87 | UNLOCK; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | ||
93 | /* Put STRING, which is of the form "NAME=VALUE", in the environment. | |
94 | If STRING contains no '=', then remove STRING from the environment. */ | |
95 | int | |
96 | putenv (char *string) | |
97 | { | |
98 | const char *const name_end = strchr (string, '='); | |
99 | register size_t size; | |
100 | register char **ep; | |
101 | ||
102 | if (name_end == NULL) | |
103 | { | |
104 | /* Remove the variable from the environment. */ | |
105 | return _unsetenv (string); | |
106 | } | |
107 | ||
108 | size = 0; | |
109 | for (ep = environ; *ep != NULL; ++ep) | |
110 | if (!strncmp (*ep, string, name_end - string) && | |
111 | (*ep)[name_end - string] == '=') | |
112 | break; | |
113 | else | |
114 | ++size; | |
115 | ||
116 | if (*ep == NULL) | |
117 | { | |
118 | static char **last_environ = NULL; | |
119 | char **new_environ = (char **) malloc ((size + 2) * sizeof (char *)); | |
120 | if (new_environ == NULL) | |
121 | return -1; | |
122 | (void) memcpy ((void *) new_environ, (void *) environ, | |
123 | size * sizeof (char *)); | |
124 | new_environ[size] = (char *) string; | |
125 | new_environ[size + 1] = NULL; | |
126 | free (last_environ); | |
127 | last_environ = new_environ; | |
128 | environ = new_environ; | |
129 | } | |
130 | else | |
131 | *ep = string; | |
132 | ||
133 | return 0; | |
134 | } |