44 lines
2.4 KiB
C
44 lines
2.4 KiB
C
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/safemacros.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Removes environment variable.
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*/
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int unsetenv(const char *name) {
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if (isempty(name) || strchr(name, '=')) return einval();
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if (environ) {
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char **ep = environ;
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size_t removed = 0;
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size_t namelen = strlen(name);
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do {
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if (*ep && strncmp(*ep, name, namelen) == 0 && (*ep)[namelen] == '=') {
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--removed;
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} else if (removed) {
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ep[removed] = *ep;
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}
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} while (*ep++);
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}
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return 0;
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}
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