contrib/bmake/setenv.c

   1 /*
   2  * Copyright (c) 1987 Regents of the University of California.
   3  * 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 #ifdef HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37 #ifndef HAVE_SETENV
  38
  39 #if defined(LIBC_SCCS) && !defined(lint)
  40 /*static char *sccsid = "from: @(#)setenv.c     5.6 (Berkeley) 6/4/91";*/
  41 static char *rcsid = "$Id: setenv.c,v 1.5 1996/09/04 22:10:42 sjg Exp $";
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <stddef.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47
  48 /*
  49  * __findenv --
  50  *      Returns pointer to value associated with name, if any, else NULL.
  51  *      Sets offset to be the offset of the name/value combination in the
  52  *      environmental array, for use by setenv(3) and unsetenv(3).
  53  *      Explicitly removes '=' in argument name.
  54  *
  55  *      This routine *should* be a static; don't use it.
  56  */
  57 static char *
  58 __findenv(name, offset)
  59         register char *name;
  60         int *offset;
  61 {
  62         extern char **environ;
  63         register int len;
  64         register char **P, *C;
  65
  66         for (C = name, len = 0; *C && *C != '='; ++C, ++len);
  67         for (P = environ; *P; ++P)
  68                 if (!strncmp(*P, name, len))
  69                         if (*(C = *P + len) == '=') {
  70                                 *offset = P - environ;
  71                                 return(++C);
  72                         }
  73         return(NULL);
  74 }
  75
  76 /*
  77  * setenv --
  78  *      Set the value of the environmental variable "name" to be
  79  *      "value".  If rewrite is set, replace any current value.
  80  */
  81 setenv(name, value, rewrite)
  82         register const char *name;
  83         register const char *value;
  84         int rewrite;
  85 {
  86         extern char **environ;
  87         static int alloced;                     /* if allocated space before */
  88         register char *C;
  89         int l_value, offset;
  90         char *__findenv();
  91
  92         if (*value == '=')                      /* no `=' in value */
  93                 ++value;
  94         l_value = strlen(value);
  95         if ((C = __findenv(name, &offset))) {   /* find if already exists */
  96                 if (!rewrite)
  97                         return (0);
  98                 if (strlen(C) >= l_value) {     /* old larger; copy over */
  99                         while (*C++ = *value++);
 100                         return (0);
 101                 }
 102         } else {                                        /* create new slot */
 103                 register int    cnt;
 104                 register char   **P;
 105
 106                 for (P = environ, cnt = 0; *P; ++P, ++cnt);
 107                 if (alloced) {                  /* just increase size */
 108                         environ = (char **)realloc((char *)environ,
 109                             (size_t)(sizeof(char *) * (cnt + 2)));
 110                         if (!environ)
 111                                 return (-1);
 112                 }
 113                 else {                          /* get new space */
 114                         alloced = 1;            /* copy old entries into it */
 115                         P = (char **)malloc((size_t)(sizeof(char *) *
 116                             (cnt + 2)));
 117                         if (!P)
 118                                 return (-1);
 119                         bcopy(environ, P, cnt * sizeof(char *));
 120                         environ = P;
 121                 }
 122                 environ[cnt + 1] = NULL;
 123                 offset = cnt;
 124         }
 125         for (C = (char *)name; *C && *C != '='; ++C);   /* no `=' in name */
 126         if (!(environ[offset] =                 /* name + `=' + value */
 127             malloc((size_t)((int)(C - name) + l_value + 2))))
 128                 return (-1);
 129         for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
 130                 ;
 131         for (*C++ = '='; *C++ = *value++; )
 132                 ;
 133         return (0);
 134 }
 135
 136 /*
 137  * unsetenv(name) --
 138  *      Delete environmental variable "name".
 139  */
 140 void
 141 unsetenv(name)
 142         const char      *name;
 143 {
 144         extern char **environ;
 145         register char **P;
 146         int offset;
 147         char *__findenv();
 148
 149         while (__findenv(name, &offset))                /* if set multiple times */
 150                 for (P = &environ[offset];; ++P)
 151                         if (!(*P = *(P + 1)))
 152                                 break;
 153 }
 154 #endif