BSD 4_4_Lite1 release

[unix-history] / usr / src / contrib / mh-6.8.3a / sbr / putenv.c

/* putenv.c - (un) set an envariable */
#ifndef lint
static char ident[] = "@(#)$Id: putenv.c,v 1.6 1992/12/15 00:20:22 jromine Exp $";
#endif  /* lint */

#include "../h/mh.h"
#include <stdio.h>


extern  char **environ;

static nvmatch();

int     m_putenv (name, value)
register char  *name,
              *value;
{
   register int    i;
   register char **ep,
                 **nep,
                  *cp;

   if ((cp = malloc ((unsigned) (strlen (name) + strlen (value) + 2)))
           == NULL)
       return 1;
   (void) sprintf (cp, "%s=%s", name, value);

   for (ep = environ, i = 0; *ep; ep++, i++)
       if (nvmatch (name, *ep)) {
           *ep = cp;
           return 0;
       }

   if ((nep = (char **) malloc ((unsigned) ((i + 2) * sizeof *nep))) == NULL)
       return 1;
   for (ep = environ, i = 0; *ep; nep[i++] = *ep++)
       continue;
   nep[i++] = cp;
   nep[i] = NULL;
   environ = nep;
   return 0;
}


int     unputenv (name)
char   *name;
{
   char  **ep,
         **nep;

   for (ep = environ; *ep; ep++)
       if (nvmatch (name, *ep))
           break;
   if (*ep == NULL)
       return 1;

   for (nep = ep + 1; *nep; nep++)
       continue;
   *ep = *--nep;
   *nep = NULL;
   return 0;
}

/* \f */

static nvmatch (s1, s2)
register char  *s1,
              *s2;
{
   while (*s1 == *s2++)
       if (*s1++ == '=')
           return 1;

   return (*s1 == '\0' && *--s2 == '=');
}