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Diffstat (limited to 'lisp/getenv.c')
-rw-r--r-- | lisp/getenv.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/lisp/getenv.c b/lisp/getenv.c new file mode 100644 index 0000000..fd8482e --- /dev/null +++ b/lisp/getenv.c @@ -0,0 +1,81 @@ +/* $OpenBSD: getenv.c,v 1.10 2010/08/23 22:31:50 millert Exp $ */ +/* + * Copyright (c) 1987, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <stdlib.h> +#include <string.h> + +char *__findenv(const char *name, int len, int *offset); + +/* + * __findenv -- + * Returns pointer to value associated with name, if any, else NULL. + * Starts searching within the environmental array at offset. + * Sets offset to be the offset of the name/value combination in the + * environmental array, for use by putenv(3), setenv(3) and unsetenv(3). + * Explicitly removes '=' in argument name. + * + * This routine *should* be a static; don't use it. + */ +char * +__findenv(const char *name, int len, int *offset) +{ + extern char **environ; + int i; + const char *np; + char **p, *cp; + + if (name == NULL || environ == NULL) + return (NULL); + for (p = environ + *offset; (cp = *p) != NULL; ++p) { + for (np = name, i = len; i && *cp; i--) + if (*cp++ != *np++) + break; + if (i == 0 && *cp++ == '=') { + *offset = p - environ; + return (cp); + } + } + return (NULL); +} + +/* + * getenv -- + * Returns ptr to value associated with name, if any, else NULL. + */ +char * +getenv(const char *name) +{ + int offset = 0; + const char *np; + + for (np = name; *np && *np != '='; ++np) + ; + return (__findenv(name, (int)(np - name), &offset)); +} |