compilers/linux86-0.16.17/libc/misc/putenv.c

   1 /* Copyright (C) 1995,1996 Robert de Bath <rdebath@cix.compulink.co.uk>
   2  * This file is part of the Linux-8086 C library and is distributed
   3  * under the GNU Library General Public License.
   4  */
   5 #include <string.h>
   6 #include <stdlib.h>
   7 #include <malloc.h>
   8
   9 extern char ** environ;
  10 #define ADD_NUM 4
  11
  12 int
  13 putenv(var)
  14 char * var;
  15 {
  16 static char ** mall_env = 0;
  17 static int extras = 0;
  18    char **p, **d;
  19    char * r;
  20    int len;
  21
  22    r = strchr(var, '=');
  23    if( r == 0 )  len = strlen(var);
  24    else          len = r-var;
  25
  26    for(p=environ; *p; p++)
  27    {
  28       if( memcmp(var, *p, len) == 0 && (*p)[len] == '=' )
  29       {
  30          while( p[0] = p[1] ) p++;
  31          extras++;
  32          break;
  33       }
  34    }
  35    if( r == 0 ) return 0;
  36    if( extras <= 0 )    /* Need more space */
  37    {
  38       d = malloc((p-environ+1+ADD_NUM)*sizeof(char*));
  39       if( d == 0 ) return -1;
  40
  41       memcpy((void*) d, (void*) environ, (p-environ+1)*sizeof(char*));
  42       p = d + (p-environ);
  43       extras=ADD_NUM;
  44
  45       if( mall_env ) free(mall_env);
  46       environ = d;
  47       mall_env = d;
  48    }
  49    *p++ = var;
  50    *p = '\0';
  51    extras--;
  52
  53    return 0;
  54 }
  55
  56