77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
/*
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* Copyright (c) 2010 Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif /* HAVE_STRINGS_H */
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#include <errno.h>
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#include "missing.h"
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extern char **environ; /* global environment */
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#ifdef UNSETENV_VOID
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void
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#else
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int
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#endif
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unsetenv(const char *var)
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{
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char **ep = environ;
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size_t len;
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if (var == NULL || *var == '\0' || strchr(var, '=') != NULL) {
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errno = EINVAL;
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#ifdef UNSETENV_VOID
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return;
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#else
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return -1;
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#endif
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}
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len = strlen(var);
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while (*ep != NULL) {
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if (strncmp(var, *ep, len) == 0 && (*ep)[len] == '=') {
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/* Found it; shift remainder + NULL over by one. */
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char **cur = ep;
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while ((*cur = *(cur + 1)) != NULL)
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cur++;
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/* Keep going, could be multiple instances of the var. */
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} else {
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ep++;
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}
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}
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#ifndef UNSETENV_VOID
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return 0;
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#endif
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}
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