external/bsd/nvi/dist/clib/env.c

   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 "config.h"
  35
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 static const char sccsid[] = "@(#)getenv.c      8.1 (Berkeley) 6/4/93";
  38 static const char sccsid[] = "@(#)setenv.c      8.1 (Berkeley) 6/4/93";
  39 #endif /* LIBC_SCCS and not lint */
  40 #else
  41 __RCSID("$NetBSD: env.c,v 1.2 2014/01/26 21:43:45 christos Exp $");
  42 #endif
  43
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 /*
  48  * __findenv --
  49  *      Returns pointer to value associated with name, if any, else NULL.
  50  *      Sets offset to be the offset of the name/value combination in the
  51  *      environmental array, for use by setenv(3) and unsetenv(3).
  52  *      Explicitly removes '=' in argument name.
  53  *
  54  *      This routine *should* be a static; don't use it.
  55  */
  56 static char *
  57 __findenv(register char *name, int *offset)
  58 {
  59         extern char **environ;
  60         register int len;
  61         register char *np;
  62         register char **p, *c;
  63
  64         if (name == NULL || environ == NULL)
  65                 return (NULL);
  66         for (np = name; *np && *np != '='; ++np)
  67                 continue;
  68         len = np - name;
  69         for (p = environ; (c = *p) != NULL; ++p)
  70                 if (strncmp(c, name, len) == 0 && c[len] == '=') {
  71                         *offset = p - environ;
  72                         return (c + len + 1);
  73                 }
  74         return (NULL);
  75 }
  76
  77 #ifndef HAVE_SETENV
  78 /*
  79  * setenv --
  80  *      Set the value of the environmental variable "name" to be
  81  *      "value".  If rewrite is set, replace any current value.
  82  *
  83  * PUBLIC: #ifndef HAVE_SETENV
  84  * PUBLIC: int setenv __P((const char *, const char *, int));
  85  * PUBLIC: #endif
  86  */
  87 setenv(name, value, rewrite)
  88         register char *name;
  89         register char *value;
  90         int rewrite;
  91 {
  92         extern char **environ;
  93         static int alloced;                     /* if allocated space before */
  94         register char *c;
  95         int l_value, offset;
  96
  97         if (*value == '=')                      /* no `=' in value */
  98                 ++value;
  99         l_value = strlen(value);
 100         if ((c = __findenv(name, &offset))) {   /* find if already exists */
 101                 if (!rewrite)
 102                         return (0);
 103                 if (strlen(c) >= l_value) {     /* old larger; copy over */
 104                         while (*c++ = *value++);
 105                         return (0);
 106                 }
 107         } else {                                        /* create new slot */
 108                 register int cnt;
 109                 register char **p;
 110
 111                 for (p = environ, cnt = 0; *p; ++p, ++cnt);
 112                 if (alloced) {                  /* just increase size */
 113                         environ = (char **)realloc((char *)environ,
 114                             (size_t)(sizeof(char *) * (cnt + 2)));
 115                         if (!environ)
 116                                 return (-1);
 117                 }
 118                 else {                          /* get new space */
 119                         alloced = 1;            /* copy old entries into it */
 120                         p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
 121                         if (!p)
 122                                 return (-1);
 123                         memmove(p, environ, cnt * sizeof(char *));
 124                         environ = p;
 125                 }
 126                 environ[cnt + 1] = NULL;
 127                 offset = cnt;
 128         }
 129         for (c = (char *)name; *c && *c != '='; ++c);   /* no `=' in name */
 130         if (!(environ[offset] =                 /* name + `=' + value */
 131             malloc((size_t)((int)(c - name) + l_value + 2))))
 132                 return (-1);
 133         for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
 134         for (*c++ = '='; *c++ = *value++;);
 135         return (0);
 136 }
 137 #endif
 138
 139 #ifndef HAVE_UNSETENV
 140 /*
 141  * unsetenv(name) --
 142  *      Delete environmental variable "name".
 143  *
 144  * PUBLIC: #ifndef HAVE_UNSETENV
 145  * PUBLIC: void unsetenv __P((const char *));
 146  * PUBLIC: #endif
 147  */
 148 void
 149 unsetenv(name)
 150         char *name;
 151 {
 152         extern char **environ;
 153         register char **p;
 154         int offset;
 155
 156         while (__findenv(name, &offset))        /* if set multiple times */
 157                 for (p = &environ[offset];; ++p)
 158                         if (!(*p = *(p + 1)))
 159                                 break;
 160 }
 161 #endif