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-rw-r--r--gl/unsetenv.c120
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diff --git a/gl/unsetenv.c b/gl/unsetenv.c
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1/* Copyright (C) 1992, 1995-2002, 2005-2010 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program 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
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17#include <config.h>
18
19/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
20 optimizes away the name == NULL test below. */
21#define _GL_ARG_NONNULL(params)
22
23/* Specification. */
24#include <stdlib.h>
25
26#include <errno.h>
27#if !_LIBC
28# define __set_errno(ev) ((errno) = (ev))
29#endif
30
31#include <string.h>
32#include <unistd.h>
33
34#if !_LIBC
35# define __environ environ
36#endif
37
38#if _LIBC
39/* This lock protects against simultaneous modifications of `environ'. */
40# include <bits/libc-lock.h>
41__libc_lock_define_initialized (static, envlock)
42# define LOCK __libc_lock_lock (envlock)
43# define UNLOCK __libc_lock_unlock (envlock)
44#else
45# define LOCK
46# define UNLOCK
47#endif
48
49/* In the GNU C library we must keep the namespace clean. */
50#ifdef _LIBC
51# define unsetenv __unsetenv
52#endif
53
54#if _LIBC || !HAVE_UNSETENV
55
56int
57unsetenv (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#ifdef _LIBC
93# undef unsetenv
94weak_alias (__unsetenv, unsetenv)
95#endif
96
97#else /* HAVE_UNSETENV */
98
99# undef unsetenv
100
101/* Call the underlying unsetenv, in case there is hidden bookkeeping
102 that needs updating beyond just modifying environ. */
103int
104rpl_unsetenv (const char *name)
105{
106 int result = 0;
107 if (!name || !*name || strchr (name, '='))
108 {
109 errno = EINVAL;
110 return -1;
111 }
112 while (getenv (name))
113# if !VOID_UNSETENV
114 result =
115# endif
116 unsetenv (name);
117 return result;
118}
119
120#endif /* HAVE_UNSETENV */