1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
/* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2012 Free Software
Foundation, Inc.
NOTE: The canonical source of this file is maintained with the GNU C
Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or any
later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <stdlib.h>
#include <stddef.h>
/* Include errno.h *after* sys/types.h to work around header problems
on AIX 3.2.5. */
#include <errno.h>
#ifndef __set_errno
# define __set_errno(ev) ((errno) = (ev))
#endif
#include <string.h>
#include <unistd.h>
#if _LIBC
# if HAVE_GNU_LD
# define environ __environ
# else
extern char **environ;
# endif
#endif
#if _LIBC
/* This lock protects against simultaneous modifications of 'environ'. */
# include <bits/libc-lock.h>
__libc_lock_define_initialized (static, envlock)
# define LOCK __libc_lock_lock (envlock)
# define UNLOCK __libc_lock_unlock (envlock)
#else
# define LOCK
# define UNLOCK
#endif
static int
_unsetenv (const char *name)
{
size_t len;
char **ep;
if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
{
__set_errno (EINVAL);
return -1;
}
len = strlen (name);
LOCK;
ep = environ;
while (*ep != NULL)
if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
{
/* Found it. Remove this pointer by moving later ones back. */
char **dp = ep;
do
dp[0] = dp[1];
while (*dp++);
/* Continue the loop in case NAME appears again. */
}
else
++ep;
UNLOCK;
return 0;
}
/* Put STRING, which is of the form "NAME=VALUE", in the environment.
If STRING contains no '=', then remove STRING from the environment. */
int
putenv (char *string)
{
const char *const name_end = strchr (string, '=');
register size_t size;
register char **ep;
if (name_end == NULL)
{
/* Remove the variable from the environment. */
return _unsetenv (string);
}
size = 0;
for (ep = environ; *ep != NULL; ++ep)
if (!strncmp (*ep, string, name_end - string) &&
(*ep)[name_end - string] == '=')
break;
else
++size;
if (*ep == NULL)
{
static char **last_environ = NULL;
char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
if (new_environ == NULL)
return -1;
(void) memcpy ((void *) new_environ, (void *) environ,
size * sizeof (char *));
new_environ[size] = (char *) string;
new_environ[size + 1] = NULL;
free (last_environ);
last_environ = new_environ;
environ = new_environ;
}
else
*ep = string;
return 0;
}
|
