openbsd-compat/setenv.c

   1 /*      $OpenBSD: setenv.c,v 1.9 2005/08/08 08:05:37 espie Exp $ */
   2 /*
   3  * Copyright (c) 1987 Regents of the University of California.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 /* OPENBSD ORIGINAL: lib/libc/stdlib/setenv.c */
  32
  33 #include "includes.h"
  34 #if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
  35
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 extern char **environ;
  40
  41 /* OpenSSH Portable: __findenv is from getenv.c rev 1.8, made static */
  42 /*
  43  * __findenv --
  44  *      Returns pointer to value associated with name, if any, else NULL.
  45  *      Sets offset to be the offset of the name/value combination in the
  46  *      environmental array, for use by setenv(3) and unsetenv(3).
  47  *      Explicitly removes '=' in argument name.
  48  */
  49 static char *
  50 __findenv(const char *name, size_t *offset)
  51 {
  52         extern char **environ;
  53         int len, i;
  54         const char *np;
  55         char **p, *cp;
  56
  57         if (name == NULL || environ == NULL)
  58                 return (NULL);
  59         for (np = name; *np && *np != '='; ++np)
  60                 ;
  61         len = np - name;
  62         for (p = environ; (cp = *p) != NULL; ++p) {
  63                 for (np = name, i = len; i && *cp; i--)
  64                         if (*cp++ != *np++)
  65                                 break;
  66                 if (i == 0 && *cp++ == '=') {
  67                         *offset = p - environ;
  68                         return (cp);
  69                 }
  70         }
  71         return (NULL);
  72 }
  73
  74 #ifndef HAVE_SETENV
  75 /*
  76  * setenv --
  77  *      Set the value of the environmental variable "name" to be
  78  *      "value".  If rewrite is set, replace any current value.
  79  */
  80 int
  81 setenv(const char *name, const char *value, int rewrite)
  82 {
  83         static char **lastenv;                  /* last value of environ */
  84         char *C;
  85         size_t l_value, offset;
  86
  87         if (*value == '=')                      /* no `=' in value */
  88                 ++value;
  89         l_value = strlen(value);
  90         if ((C = __findenv(name, &offset))) {   /* find if already exists */
  91                 if (!rewrite)
  92                         return (0);
  93                 if (strlen(C) >= l_value) {     /* old larger; copy over */
  94                         while ((*C++ = *value++))
  95                                 ;
  96                         return (0);
  97                 }
  98         } else {                                        /* create new slot */
  99                 size_t cnt;
 100                 char **P;
 101
 102                 for (P = environ; *P != NULL; P++)
 103                         ;
 104                 cnt = P - environ;
 105                 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2));
 106                 if (!P)
 107                         return (-1);
 108                 if (lastenv != environ)
 109                         memcpy(P, environ, cnt * sizeof(char *));
 110                 lastenv = environ = P;
 111                 offset = cnt;
 112                 environ[cnt + 1] = NULL;
 113         }
 114         for (C = (char *)name; *C && *C != '='; ++C)
 115                 ;                               /* no `=' in name */
 116         if (!(environ[offset] =                 /* name + `=' + value */
 117             malloc((size_t)((int)(C - name) + l_value + 2))))
 118                 return (-1);
 119         for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
 120                 ;
 121         for (*C++ = '='; (*C++ = *value++); )
 122                 ;
 123         return (0);
 124 }
 125 #endif /* HAVE_SETENV */
 126
 127 #ifndef HAVE_UNSETENV
 128 /*
 129  * unsetenv(name) --
 130  *      Delete environmental variable "name".
 131  */
 132 void
 133 unsetenv(const char *name)
 134 {
 135         char **P;
 136         size_t offset;
 137
 138         while (__findenv(name, &offset))        /* if set multiple times */
 139                 for (P = &environ[offset];; ++P)
 140                         if (!(*P = *(P + 1)))
 141                                 break;
 142 }
 143 #endif /* HAVE_UNSETENV */
 144
 145 #endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */