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comparison libiberty/setenv.c @ 0:a06113de4d67

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first commit
author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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children f6334be47118
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-1:000000000000 0:a06113de4d67
1 /* Copyright (C) 1992, 1995, 1996, 1997, 2002 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}, const char *@var{value}, int @var{overwrite})
23 @deftypefnx Supplemental void unsetenv (const char *@var{name})
24
25 @code{setenv} adds @var{name} to the environment with value
26 @var{value}. If the name was already present in the environment,
27 the new value will be stored only if @var{overwrite} is nonzero.
28 The companion @code{unsetenv} function removes @var{name} from the
29 environment. This implementation is not safe for multithreaded code.
30
31 @end deftypefn
32
33 */
34
35 #if HAVE_CONFIG_H
36 # include <config.h>
37 #endif
38
39 #define setenv libiberty_setenv
40 #define unsetenv libiberty_unsetenv
41
42 #include "ansidecl.h"
43 #include <sys/types.h> /* For `size_t' */
44 #include <stdio.h> /* For `NULL' */
45
46 #include <errno.h>
47 #if !defined(errno) && !defined(HAVE_ERRNO_DECL)
48 extern int errno;
49 #endif
50 #define __set_errno(ev) ((errno) = (ev))
51
52 #if HAVE_STDLIB_H
53 # include <stdlib.h>
54 #endif
55 #if HAVE_STRING_H
56 # include <string.h>
57 #endif
58 #if HAVE_UNISTD_H
59 # include <unistd.h>
60 #endif
61
62 #define __environ environ
63 #ifndef HAVE_ENVIRON_DECL
64 extern char **environ;
65 #endif
66
67 #undef setenv
68 #undef unsetenv
69
70 /* LOCK and UNLOCK are defined as no-ops. This makes the libiberty
71 * implementation MT-Unsafe. */
72 #define LOCK
73 #define UNLOCK
74
75 /* Below this point, it's verbatim code from the glibc-2.0 implementation */
76
77 /* If this variable is not a null pointer we allocated the current
78 environment. */
79 static char **last_environ;
80
81
82 int
83 setenv (const char *name, const char *value, int replace)
84 {
85 register char **ep = 0;
86 register size_t size;
87 const size_t namelen = strlen (name);
88 const size_t vallen = strlen (value) + 1;
89
90 LOCK;
91
92 size = 0;
93 if (__environ != NULL)
94 {
95 for (ep = __environ; *ep != NULL; ++ep)
96 if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
97 break;
98 else
99 ++size;
100 }
101
102 if (__environ == NULL || *ep == NULL)
103 {
104 char **new_environ;
105 if (__environ == last_environ && __environ != NULL)
106 /* We allocated this space; we can extend it. */
107 new_environ = (char **) realloc (last_environ,
108 (size + 2) * sizeof (char *));
109 else
110 new_environ = (char **) malloc ((size + 2) * sizeof (char *));
111
112 if (new_environ == NULL)
113 {
114 UNLOCK;
115 return -1;
116 }
117
118 new_environ[size] = (char *) malloc (namelen + 1 + vallen);
119 if (new_environ[size] == NULL)
120 {
121 free ((char *) new_environ);
122 __set_errno (ENOMEM);
123 UNLOCK;
124 return -1;
125 }
126
127 if (__environ != last_environ)
128 memcpy ((char *) new_environ, (char *) __environ,
129 size * sizeof (char *));
130
131 memcpy (new_environ[size], name, namelen);
132 new_environ[size][namelen] = '=';
133 memcpy (&new_environ[size][namelen + 1], value, vallen);
134
135 new_environ[size + 1] = NULL;
136
137 last_environ = __environ = new_environ;
138 }
139 else if (replace)
140 {
141 size_t len = strlen (*ep);
142 if (len + 1 < namelen + 1 + vallen)
143 {
144 /* The existing string is too short; malloc a new one. */
145 char *new_string = (char *) malloc (namelen + 1 + vallen);
146 if (new_string == NULL)
147 {
148 UNLOCK;
149 return -1;
150 }
151 *ep = new_string;
152 }
153 memcpy (*ep, name, namelen);
154 (*ep)[namelen] = '=';
155 memcpy (&(*ep)[namelen + 1], value, vallen);
156 }
157
158 UNLOCK;
159
160 return 0;
161 }
162
163 void
164 unsetenv (const char *name)
165 {
166 const size_t len = strlen (name);
167 char **ep;
168
169 LOCK;
170
171 for (ep = __environ; *ep; ++ep)
172 if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
173 {
174 /* Found it. Remove this pointer by moving later ones back. */
175 char **dp = ep;
176 do
177 dp[0] = dp[1];
178 while (*dp++);
179 /* Continue the loop in case NAME appears again. */
180 }
181
182 UNLOCK;
183 }