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

   1 /* putenv.c -- (un)set an envariable
   2  *
   3  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/utils.h>
  10
  11 extern char **environ;
  12
  13 /*
  14  * prototypes
  15  */
  16 int m_putenv (char *, char *);
  17 int unputenv (char *);
  18 static int nvmatch (char *, char *);
  19
  20 /* FIXME: These functions leak memory.  No easy fix since they might not
  21  * be malloc'd.  Switch to setenv(3) and unsetenv(3). */
  22
  23 int
  24 m_putenv (char *name, char *value)
  25 {
  26     int i;
  27     char **ep, **nep, *cp;
  28
  29     cp = concat(name, "=", value, NULL);
  30
  31     for (ep = environ, i = 0; *ep; ep++, i++)
  32         if (nvmatch (name, *ep)) {
  33             *ep = cp;
  34             return 0;
  35         }
  36
  37     nep = (char **) mh_xmalloc ((size_t) ((i + 2) * sizeof(*nep)));
  38
  39     for (ep = environ, i = 0; *ep; nep[i++] = *ep++)
  40         continue;
  41     nep[i++] = cp;
  42     nep[i] = NULL;
  43     environ = nep;
  44     return 0;
  45 }
  46
  47
  48 int
  49 unputenv (char *name)
  50 {
  51     char **ep, **nep;
  52
  53     for (ep = environ; *ep; ep++)
  54         if (nvmatch (name, *ep))
  55             break;
  56     if (*ep == NULL)
  57         return 1;
  58
  59     for (nep = ep + 1; *nep; nep++)
  60         continue;
  61     *ep = *--nep;
  62     *nep = NULL;
  63     return 0;
  64 }
  65
  66
  67 static int
  68 nvmatch (char *s1, char *s2)
  69 {
  70     while (*s1 == *s2++)
  71         if (*s1++ == '=')
  72             return 1;
  73
  74     return (*s1 == '\0' && *--s2 == '=');
  75 }