1 /* Copyright (C) 1992-2023 Free Software Foundation, Inc.
2 This file based on setenv.c in the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library 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 GNU
12 Library General Public License for more details.
13
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
17 Boston, MA 02110-1301, USA. */
18
19
20 /*
21
22 @deftypefn Supplemental int setenv (const char *@var{name}, @
23 const char *@var{value}, int @var{overwrite})
24 @deftypefnx Supplemental void unsetenv (const char *@var{name})
25
26 @code{setenv} adds @var{name} to the environment with value
27 @var{value}. If the name was already present in the environment,
28 the new value will be stored only if @var{overwrite} is nonzero.
29 The companion @code{unsetenv} function removes @var{name} from the
30 environment. This implementation is not safe for multithreaded code.
31
32 @end deftypefn
33
34 */
35
36 #if HAVE_CONFIG_H
37 # include <config.h>
38 #endif
39
40 #define setenv libiberty_setenv
41 #define unsetenv libiberty_unsetenv
42
43 #include "ansidecl.h"
44 #include <sys/types.h> /* For `size_t' */
45 #include <stdio.h> /* For `NULL' */
46
47 #include <errno.h>
48 #if !defined(errno) && !defined(HAVE_ERRNO_DECL)
49 extern int errno;
50 #endif
51 #define __set_errno(ev) ((errno) = (ev))
52
53 #if HAVE_STDLIB_H
54 # include <stdlib.h>
55 #endif
56 #if HAVE_STRING_H
57 # include <string.h>
58 #endif
59 #if HAVE_UNISTD_H
60 # include <unistd.h>
61 #endif
62
63 #define __environ environ
64 #include "environ.h"
65
66 #undef setenv
67 #undef unsetenv
68
69 /* LOCK and UNLOCK are defined as no-ops. This makes the libiberty
70 * implementation MT-Unsafe. */
71 #define LOCK
72 #define UNLOCK
73
74 /* Below this point, it's verbatim code from the glibc-2.0 implementation */
75
76 /* If this variable is not a null pointer we allocated the current
77 environment. */
78 static char **last_environ;
79
80
81 int
82 setenv (const char *name, const char *value, int replace)
83 {
84 register char **ep = 0;
85 register size_t size;
86 const size_t namelen = strlen (name);
87 const size_t vallen = strlen (value) + 1;
88
89 LOCK;
90
91 size = 0;
92 if (__environ != NULL)
93 {
94 for (ep = __environ; *ep != NULL; ++ep)
95 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
96 break;
97 else
98 ++size;
99 }
100
101 if (__environ == NULL || *ep == NULL)
102 {
103 char **new_environ;
104 if (__environ == last_environ && __environ != NULL)
105 /* We allocated this space; we can extend it. */
106 new_environ = (char **) realloc (last_environ,
107 (size + 2) * sizeof (char *));
108 else
109 new_environ = (char **) malloc ((size + 2) * sizeof (char *));
110
111 if (new_environ == NULL)
112 {
113 UNLOCK;
114 return -1;
115 }
116
117 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
118 if (new_environ[size] == NULL)
119 {
120 free ((char *) new_environ);
121 __set_errno (ENOMEM);
122 UNLOCK;
123 return -1;
124 }
125
126 if (__environ != last_environ)
127 memcpy ((char *) new_environ, (char *) __environ,
128 size * sizeof (char *));
129
130 memcpy (new_environ[size], name, namelen);
131 new_environ[size][namelen] = '=';
132 memcpy (&new_environ[size][namelen + 1], value, vallen);
133
134 new_environ[size + 1] = NULL;
135
136 last_environ = __environ = new_environ;
137 }
138 else if (replace)
139 {
140 size_t len = strlen (*ep);
141 if (len + 1 < namelen + 1 + vallen)
142 {
143 /* The existing string is too short; malloc a new one. */
144 char *new_string = (char *) malloc (namelen + 1 + vallen);
145 if (new_string == NULL)
146 {
147 UNLOCK;
148 return -1;
149 }
150 *ep = new_string;
151 }
152 memcpy (*ep, name, namelen);
153 (*ep)[namelen] = '=';
154 memcpy (&(*ep)[namelen + 1], value, vallen);
155 }
156
157 UNLOCK;
158
159 return 0;
160 }
161
162 void
163 unsetenv (const char *name)
164 {
165 const size_t len = strlen (name);
166 char **ep;
167
168 LOCK;
169
170 for (ep = __environ; *ep; ++ep)
171 if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
172 {
173 /* Found it. Remove this pointer by moving later ones back. */
174 char **dp = ep;
175 do
176 dp[0] = dp[1];
177 while (*dp++);
178 /* Continue the loop in case NAME appears again. */
179 }
180
181 UNLOCK;
182 }