openbsd-compat/setenv.c

   1 /* OPENBSD ORIGINAL: lib/libc/stdlib/setenv.c */
   2
   3 /*
   4  * Copyright (c) 1987 Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include "includes.h"
  33 #if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
  34
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 static char *rcsid = "$OpenBSD: setenv.c,v 1.6 2003/06/02 20:18:38 millert Exp $";
  37 #endif /* LIBC_SCCS and not lint */
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 char *__findenv(const char *name, int *offset);
  43
  44 /*
  45  * __findenv --
  46  *      Returns pointer to value associated with name, if any, else NULL.
  47  *      Sets offset to be the offset of the name/value combination in the
  48  *      environmental array, for use by setenv(3) and unsetenv(3).
  49  *      Explicitly removes '=' in argument name.
  50  *
  51  *      This routine *should* be a static; don't use it.
  52  */
  53 char *
  54 __findenv(name, offset)
  55         register const char *name;
  56         int *offset;
  57 {
  58         extern char **environ;
  59         register int len, i;
  60         register const char *np;
  61         register char **p, *cp;
  62
  63         if (name == NULL || environ == NULL)
  64                 return (NULL);
  65         for (np = name; *np && *np != '='; ++np)
  66                 ;
  67         len = np - name;
  68         for (p = environ; (cp = *p) != NULL; ++p) {
  69                 for (np = name, i = len; i && *cp; i--)
  70                         if (*cp++ != *np++)
  71                                 break;
  72                 if (i == 0 && *cp++ == '=') {
  73                         *offset = p - environ;
  74                         return (cp);
  75                 }
  76         }
  77         return (NULL);
  78 }
  79
  80 #ifndef HAVE_SETENV
  81 /*
  82  * setenv --
  83  *      Set the value of the environmental variable "name" to be
  84  *      "value".  If rewrite is set, replace any current value.
  85  */
  86 int
  87 setenv(name, value, rewrite)
  88         register const char *name;
  89         register const 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                                 ;
 106                         return (0);
 107                 }
 108         } else {                                        /* create new slot */
 109                 register int    cnt;
 110                 register char   **P;
 111
 112                 for (P = environ, cnt = 0; *P; ++P, ++cnt);
 113                 if (alloced) {                  /* just increase size */
 114                         P = (char **)realloc((void *)environ,
 115                             (size_t)(sizeof(char *) * (cnt + 2)));
 116                         if (!P)
 117                                 return (-1);
 118                         environ = P;
 119                 }
 120                 else {                          /* get new space */
 121                         alloced = 1;            /* copy old entries into it */
 122                         P = (char **)malloc((size_t)(sizeof(char *) *
 123                             (cnt + 2)));
 124                         if (!P)
 125                                 return (-1);
 126                         memmove(P, environ, cnt * sizeof(char *));
 127                         environ = P;
 128                 }
 129                 environ[cnt + 1] = NULL;
 130                 offset = cnt;
 131         }
 132         for (C = (char *)name; *C && *C != '='; ++C);   /* no `=' in name */
 133         if (!(environ[offset] =                 /* name + `=' + value */
 134             malloc((size_t)((int)(C - name) + l_value + 2))))
 135                 return (-1);
 136         for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
 137                 ;
 138         for (*C++ = '='; (*C++ = *value++); )
 139                 ;
 140         return (0);
 141 }
 142 #endif /* HAVE_SETENV */
 143
 144 #ifndef HAVE_UNSETENV
 145 /*
 146  * unsetenv(name) --
 147  *      Delete environmental variable "name".
 148  */
 149 void
 150 unsetenv(name)
 151         const char      *name;
 152 {
 153         extern char **environ;
 154         register char **P;
 155         int offset;
 156         char *__findenv();
 157
 158         while (__findenv(name, &offset))                /* if set multiple times */
 159                 for (P = &environ[offset];; ++P)
 160                         if (!(*P = *(P + 1)))
 161                                 break;
 162 }
 163 #endif /* HAVE_UNSETENV */
 164
 165 #endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */