1/* Copyright (C) 1992, 1995-2002, 2005-2012 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# if !HAVE_DECL_UNSETENV 101# if VOID_UNSETENV 102extern void unsetenv (const char *); 103# else 104extern int unsetenv (const char *); 105# endif 106# endif 107 108/* Call the underlying unsetenv, in case there is hidden bookkeeping 109 that needs updating beyond just modifying environ. */ 110int 111rpl_unsetenv (const char *name) 112{ 113 int result = 0; 114 if (!name || !*name || strchr (name, '=')) 115 { 116 errno = EINVAL; 117 return -1; 118 } 119 while (getenv (name)) 120# if !VOID_UNSETENV 121 result = 122# endif 123 unsetenv (name); 124 return result; 125} 126 127#endif /* HAVE_UNSETENV */ 128