newlib/libc/stdlib/setenv_r.c

   1 /* This file may have been modified by DJ Delorie (Jan 1991).  If so,
   2 ** these modifications are Copyright (C) 1991 DJ Delorie.
   3 */
   4
   5 /*
   6  * Copyright (c) 1987 Regents of the University of California.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms are permitted
  10  * provided that: (1) source distributions retain this entire copyright
  11  * notice and comment, and (2) distributions including binaries display
  12  * the following acknowledgement:  ``This product includes software
  13  * developed by the University of California, Berkeley and its contributors''
  14  * in the documentation or other materials provided with the distribution.
  15  * Neither the name of the University nor the names of its
  16  * contributors may be used to endorse or promote products derived
  17  * from this software without specific prior written permission.
  18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  21  */
  22
  23 #include <reent.h>
  24
  25 #include <stddef.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <time.h>
  29 #include <errno.h>
  30 #include "envlock.h"
  31
  32 extern char **environ;
  33
  34 /* Only deal with a pointer to environ, to work around subtle bugs with shared
  35    libraries and/or small data systems where the user declares his own
  36    'environ'.  */
  37 static char ***p_environ = &environ;
  38
  39 /* _findenv_r is defined in getenv_r.c.  */
  40 extern char *_findenv_r (struct _reent *, const char *, int *);
  41
  42 /*
  43  * _setenv_r --
  44  *      Set the value of the environmental variable "name" to be
  45  *      "value".  If rewrite is set, replace any current value.
  46  *      If "name" contains equal sign, -1 is returned, and errno is
  47  *      set to EINVAL;
  48  */
  49
  50 int
  51 _setenv_r (struct _reent *reent_ptr,
  52         const char *name,
  53         const char *value,
  54         int rewrite)
  55 {
  56   static int alloced;           /* if allocated space before */
  57   register char *C;
  58   int l_value, offset;
  59
  60   if (strchr(name, '='))
  61     {
  62       errno = EINVAL;
  63       return -1;
  64     }
  65
  66   ENV_LOCK;
  67
  68   l_value = strlen (value);
  69   if ((C = _findenv_r (reent_ptr, name, &offset)))
  70     {                           /* find if already exists */
  71       if (!rewrite)
  72         {
  73           ENV_UNLOCK;
  74           return 0;
  75         }
  76       if (strlen (C) >= l_value)
  77         {                       /* old larger; copy over */
  78           while ((*C++ = *value++) != 0);
  79           ENV_UNLOCK;
  80           return 0;
  81         }
  82     }
  83   else
  84     {                           /* create new slot */
  85       register int cnt;
  86       register char **P;
  87
  88       for (P = *p_environ, cnt = 0; *P; ++P, ++cnt);
  89       if (alloced)
  90         {                       /* just increase size */
  91           *p_environ = (char **) _realloc_r (reent_ptr, (char *) environ,
  92                                              (size_t) (sizeof (char *) * (cnt + 2)));
  93           if (!*p_environ)
  94             {
  95               ENV_UNLOCK;
  96               return -1;
  97             }
  98         }
  99       else
 100         {                       /* get new space */
 101           alloced = 1;          /* copy old entries into it */
 102           P = (char **) _malloc_r (reent_ptr, (size_t) (sizeof (char *) * (cnt + 2)));
 103           if (!P)
 104             {
 105               ENV_UNLOCK;
 106               return (-1);
 107             }
 108           memcpy((char *) P,(char *) *p_environ, cnt * sizeof (char *));
 109           *p_environ = P;
 110         }
 111       (*p_environ)[cnt + 1] = NULL;
 112       offset = cnt;
 113     }
 114   for (C = (char *) name; *C && *C != '='; ++C);        /* no `=' in name */
 115   if (!((*p_environ)[offset] =  /* name + `=' + value */
 116         _malloc_r (reent_ptr, (size_t) ((int) (C - name) + l_value + 2))))
 117     {
 118       ENV_UNLOCK;
 119       return -1;
 120     }
 121   for (C = (*p_environ)[offset]; (*C = *name++) && *C != '='; ++C);
 122   for (*C++ = '='; (*C++ = *value++) != 0;);
 123
 124   ENV_UNLOCK;
 125
 126   return 0;
 127 }
 128
 129 /*
 130  * _unsetenv_r(name) --
 131  *      Delete environmental variable "name".
 132  */
 133 int
 134 _unsetenv_r (struct _reent *reent_ptr,
 135         const char *name)
 136 {
 137   register char **P;
 138   int offset;
 139
 140   /* Name cannot be NULL, empty, or contain an equal sign.  */
 141   if (name == NULL || name[0] == '\0' || strchr(name, '='))
 142     {
 143       errno = EINVAL;
 144       return -1;
 145     }
 146
 147   ENV_LOCK;
 148
 149   while (_findenv_r (reent_ptr, name, &offset)) /* if set multiple times */
 150     {
 151       for (P = &(*p_environ)[offset];; ++P)
 152         if (!(*P = *(P + 1)))
 153           break;
 154     }
 155
 156   ENV_UNLOCK;
 157   return 0;
 158 }