diplodocus.org Git - nmh/blob - sbr/putenv.c

   1
   2 /*
   3  * putenv.c -- (un)set an envariable
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9
  10 extern char **environ;
  11
  12 /*
  13  * prototypes
  14  */
  15 int m_putenv (char *, char *);
  16 int unputenv (char *);
  17 static int nvmatch (char *, char *);
  18
  19
  20 int
  21 m_putenv (char *name, char *value)
  22 {
  23     register int i;
  24     register char **ep, **nep, *cp;
  25
  26     if (!(cp = malloc ((size_t) (strlen (name) + strlen (value) + 2))))
  27         return 1;
  28
  29     sprintf (cp, "%s=%s", name, value);
  30
  31     for (ep = environ, i = 0; *ep; ep++, i++)
  32         if (nvmatch (name, *ep)) {
  33             *ep = cp;
  34             return 0;
  35         }
  36
  37     if (!(nep = (char **) malloc ((size_t) ((i + 2) * sizeof(*nep)))))
  38         return 1;
  39
  40     for (ep = environ, i = 0; *ep; nep[i++] = *ep++)
  41         continue;
  42     nep[i++] = cp;
  43     nep[i] = NULL;
  44     environ = nep;
  45     return 0;
  46 }
  47
  48
  49 int
  50 unputenv (char *name)
  51 {
  52     char **ep, **nep;
  53
  54     for (ep = environ; *ep; ep++)
  55         if (nvmatch (name, *ep))
  56             break;
  57     if (*ep == NULL)
  58         return 1;
  59
  60     for (nep = ep + 1; *nep; nep++)
  61         continue;
  62     *ep = *--nep;
  63     *nep = NULL;
  64     return 0;
  65 }
  66
  67
  68 static int
  69 nvmatch (char *s1, char *s2)
  70 {
  71     while (*s1 == *s2++)
  72         if (*s1++ == '=')
  73             return 1;
  74
  75     return (*s1 == '\0' && *--s2 == '=');
  76 }