src/src/environment.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Heiko Schlittermann 2016
   6  * hs@schlittermann.de
   7  * See the file NOTICE for conditions of use and distribution.
   8  */
   9
  10 #include "exim.h"
  11
  12 #ifndef environ
  13 extern char **environ;
  14 #endif
  15
  16 /* The cleanup_environment() function is used during the startup phase
  17 of the Exim process, right after reading the configurations main
  18 part, before any expansions take place. It retains the environment
  19 variables we trust (via the keep_environment option) and allows to
  20 set additional variables (via add_environment).
  21
  22 Returns:    TRUE if successful
  23             FALSE otherwise
  24 */
  25
  26 BOOL
  27 cleanup_environment()
  28 {
  29 if (!keep_environment || *keep_environment == '\0')
  30   {
  31   /* From: https://github.com/dovecot/core/blob/master/src/lib/env-util.c#L55
  32   Try to clear the environment.
  33   a) environ = NULL crashes on OS X.
  34   b) *environ = NULL doesn't work on FreeBSD 7.0.
  35   c) environ = emptyenv doesn't work on Haiku OS
  36   d) environ = calloc() should work everywhere */
  37
  38   if (environ) *environ = NULL;
  39
  40   }
  41 else if (Ustrcmp(keep_environment, "*") != 0)
  42   {
  43   uschar **p;
  44   if (environ) for (p = USS environ; *p; /* see below */)
  45     {
  46     /* It's considered broken if we do not find the '=', according to
  47     Florian Weimer. For now we ignore such strings. unsetenv() would complain,
  48     getenv() would complain. */
  49     uschar *eqp = Ustrchr(*p, '=');
  50
  51     if (eqp)
  52       {
  53       uschar *name = string_copyn(*p, eqp - *p);
  54       if (OK != match_isinlist(name, CUSS &keep_environment,
  55           0, NULL, NULL, MCL_NOEXPAND, FALSE, NULL))
  56         if (unsetenv(CS name) < 0) return FALSE;
  57         else p = USS environ; /* RESTART from the beginning */
  58       else p++;
  59       store_reset(name);
  60       }
  61     }
  62   }
  63 if (add_environment)
  64   {
  65     uschar *p;
  66     int sep = 0;
  67     const uschar* envlist = add_environment;
  68     while ((p = string_nextinlist(&envlist, &sep, NULL, 0)))
  69         putenv(CS p);
  70   }
  71
  72   return TRUE;
  73 }