1 /* Copyright (C) 1992, 1995, 1996, 1997, 2002, 2011 Free Software Foundation,
2 Inc.
3 This file based on setenv.c in the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
18 Boston, MA 02110-1301, USA. */
19
20
21 /*
22
23 @deftypefn Supplemental int setenv (const char *@var{name}, @
24 const char *@var{value}, int @var{overwrite})
25 @deftypefnx Supplemental void unsetenv (const char *@var{name})
26
27 @code{setenv} adds @var{name} to the environment with value
28 @var{value}. If the name was already present in the environment,
29 the new value will be stored only if @var{overwrite} is nonzero.
30 The companion @code{unsetenv} function removes @var{name} from the
31 environment. This implementation is not safe for multithreaded code.
32
33 @end deftypefn
34
35 */
36
37 #if HAVE_CONFIG_H
38 # include <config.h>
39 #endif
40
41 #define setenv libiberty_setenv
42 #define unsetenv libiberty_unsetenv
43
44 #include "ansidecl.h"
45 #include <sys/types.h> /* For `size_t' */
46 #include <stdio.h> /* For `NULL' */
47
48 #include <errno.h>
49 #if !defined(errno) && !defined(HAVE_ERRNO_DECL)
50 extern int errno;
51 #endif
52 #define __set_errno(ev) ((errno) = (ev))
53
54 #if HAVE_STDLIB_H
55 # include <stdlib.h>
56 #endif
57 #if HAVE_STRING_H
58 # include <string.h>
59 #endif
60 #if HAVE_UNISTD_H
61 # include <unistd.h>
62 #endif
63
64 #define __environ environ
65 #ifndef HAVE_ENVIRON_DECL
66 extern char **environ;
67 #endif
68
69 #undef setenv
70 #undef unsetenv
71
72 /* LOCK and UNLOCK are defined as no-ops. This makes the libiberty
73 * implementation MT-Unsafe. */
74 #define LOCK
75 #define UNLOCK
76
77 /* Below this point, it's verbatim code from the glibc-2.0 implementation */
78
79 /* If this variable is not a null pointer we allocated the current
80 environment. */
81 static char **last_environ;
82
83
84 int
setenv(const char * name,const char * value,int replace)85 setenv (const char *name, const char *value, int replace)
86 {
87 register char **ep = 0;
88 register size_t size;
89 const size_t namelen = strlen (name);
90 const size_t vallen = strlen (value) + 1;
91
92 LOCK;
93
94 size = 0;
95 if (__environ != NULL)
96 {
97 for (ep = __environ; *ep != NULL; ++ep)
98 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
99 break;
100 else
101 ++size;
102 }
103
104 if (__environ == NULL || *ep == NULL)
105 {
106 char **new_environ;
107 if (__environ == last_environ && __environ != NULL)
108 /* We allocated this space; we can extend it. */
109 new_environ = (char **) realloc (last_environ,
110 (size + 2) * sizeof (char *));
111 else
112 new_environ = (char **) malloc ((size + 2) * sizeof (char *));
113
114 if (new_environ == NULL)
115 {
116 UNLOCK;
117 return -1;
118 }
119
120 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
121 if (new_environ[size] == NULL)
122 {
123 free ((char *) new_environ);
124 __set_errno (ENOMEM);
125 UNLOCK;
126 return -1;
127 }
128
129 if (__environ != last_environ)
130 memcpy ((char *) new_environ, (char *) __environ,
131 size * sizeof (char *));
132
133 memcpy (new_environ[size], name, namelen);
134 new_environ[size][namelen] = '=';
135 memcpy (&new_environ[size][namelen + 1], value, vallen);
136
137 new_environ[size + 1] = NULL;
138
139 last_environ = __environ = new_environ;
140 }
141 else if (replace)
142 {
143 size_t len = strlen (*ep);
144 if (len + 1 < namelen + 1 + vallen)
145 {
146 /* The existing string is too short; malloc a new one. */
147 char *new_string = (char *) malloc (namelen + 1 + vallen);
148 if (new_string == NULL)
149 {
150 UNLOCK;
151 return -1;
152 }
153 *ep = new_string;
154 }
155 memcpy (*ep, name, namelen);
156 (*ep)[namelen] = '=';
157 memcpy (&(*ep)[namelen + 1], value, vallen);
158 }
159
160 UNLOCK;
161
162 return 0;
163 }
164
165 void
unsetenv(const char * name)166 unsetenv (const char *name)
167 {
168 const size_t len = strlen (name);
169 char **ep;
170
171 LOCK;
172
173 for (ep = __environ; *ep; ++ep)
174 if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
175 {
176 /* Found it. Remove this pointer by moving later ones back. */
177 char **dp = ep;
178 do
179 dp[0] = dp[1];
180 while (*dp++);
181 /* Continue the loop in case NAME appears again. */
182 }
183
184 UNLOCK;
185 }
186