vx32

Local 9vx git repository for patches.
git clone git://r-36.net/vx32
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setenv.c (3752B)


      1 /*
      2  * Copyright (c) 1987, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #include <stddef.h>
     35 #include <stdlib.h>
     36 #include <string.h>
     37 
     38 char *__findenv(const char *, int *);
     39 
     40 /*
     41  * setenv --
     42  *	Set the value of the environmental variable "name" to be
     43  *	"value".  If rewrite is set, replace any current value.
     44  */
     45 int
     46 setenv(name, value, rewrite)
     47 	const char *name;
     48 	const char *value;
     49 	int rewrite;
     50 {
     51 	extern char **environ;
     52 	static char **alloced;			/* if allocated space before */
     53 	char *c;
     54 	int l_value, offset;
     55 
     56 	if (*value == '=')			/* no `=' in value */
     57 		++value;
     58 	l_value = strlen(value);
     59 	if ((c = __findenv(name, &offset))) {	/* find if already exists */
     60 		if (!rewrite)
     61 			return (0);
     62 		if (strlen(c) >= l_value) {	/* old larger; copy over */
     63 			while ( (*c++ = *value++) );
     64 			return (0);
     65 		}
     66 	} else {					/* create new slot */
     67 		int cnt;
     68 		char **p;
     69 
     70 		for (p = environ, cnt = 0; *p; ++p, ++cnt);
     71 		if (alloced == environ) {			/* just increase size */
     72 			p = (char **)realloc((char *)environ,
     73 			    (size_t)(sizeof(char *) * (cnt + 2)));
     74 			if (!p)
     75 				return (-1);
     76 			alloced = environ = p;
     77 		}
     78 		else {				/* get new space */
     79 						/* copy old entries into it */
     80 			p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
     81 			if (!p)
     82 				return (-1);
     83 			memcpy(p, environ, cnt * sizeof(char *));
     84 			alloced = environ = p;
     85 		}
     86 		environ[cnt + 1] = NULL;
     87 		offset = cnt;
     88 	}
     89 	for (c = (char *)name; *c && *c != '='; ++c);	/* no `=' in name */
     90 	if (!(environ[offset] =			/* name + `=' + value */
     91 	    malloc((size_t)((int)(c - name) + l_value + 2))))
     92 		return (-1);
     93 	for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
     94 	for (*c++ = '='; (*c++ = *value++); );
     95 	return (0);
     96 }
     97 
     98 /*
     99  * unsetenv(name) --
    100  *	Delete environmental variable "name".
    101  */
    102 int
    103 unsetenv(name)
    104 	const char *name;
    105 {
    106 	extern char **environ;
    107 	char **p;
    108 	int offset;
    109 
    110 	while (__findenv(name, &offset))	/* if set multiple times */
    111 		for (p = &environ[offset];; ++p)
    112 			if (!(*p = *(p + 1)))
    113 				break;
    114 	return 0;
    115 }