| 1 | /* Copyright (C) 1992, 1995-2002, 2005-2020 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 <https://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc |
| 18 | optimizes away the name == NULL test below. */ |
| 19 | #define _GL_ARG_NONNULL(params) |
| 20 | |
| 21 | #include <config.h> |
| 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 | |
| 56 | int |
| 57 | unsetenv (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 |
| 94 | weak_alias (__unsetenv, unsetenv) |
| 95 | #endif |
| 96 | |
| 97 | #else /* HAVE_UNSETENV */ |
| 98 | |
| 99 | # undef unsetenv |
| 100 | # if !HAVE_DECL_UNSETENV |
| 101 | # if VOID_UNSETENV |
| 102 | extern void unsetenv (const char *); |
| 103 | # else |
| 104 | extern 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. */ |
| 110 | int |
| 111 | rpl_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 */ |