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 extern char **environ;
  13
  14 /* The cleanup_environment() function is used during the startup phase
  15 of the Exim process, right after reading the configurations main
  16 part, before any expansions take place. It retains the environment
  17 variables we trust (via the keep_environment option) and allows to
  18 set additional variables (via add_environment).
  19
  20 Returns:    TRUE if successful
  21             FALSE otherwise
  22 */
  23
  24 BOOL
  25 cleanup_environment()
  26 {
  27 int old_pool = store_pool;
  28 store_pool = POOL_PERM;         /* Need perm memory for any created env vars */
  29
  30 if (!keep_environment || *keep_environment == '\0')
  31   {
  32   /* From: https://github.com/dovecot/core/blob/master/src/lib/env-util.c#L55
  33   Try to clear the environment.
  34   a) environ = NULL crashes on OS X.
  35   b) *environ = NULL doesn't work on FreeBSD 7.0.
  36   c) environ = emptyenv doesn't work on Haiku OS
  37   d) environ = calloc() should work everywhere */
  38
  39   if (environ) *environ = NULL;
  40
  41   }
  42 else if (Ustrcmp(keep_environment, "*") != 0)
  43   {
  44   rmark reset_point = store_mark();
  45   if (environ) for (uschar ** p = USS environ; *p; /* see below */)
  46     {
  47     /* It's considered broken if we do not find the '=', according to
  48     Florian Weimer. For now we ignore such strings. unsetenv() would complain,
  49     getenv() would complain. */
  50     uschar * eqp = Ustrchr(*p, '=');
  51
  52     if (eqp)
  53       {
  54       uschar * name = string_copyn(*p, eqp - *p);
  55
  56       if (OK != match_isinlist(name, CUSS &keep_environment,
  57           0, NULL, NULL, MCL_NOEXPAND, FALSE, NULL))
  58         if (os_unsetenv(name) < 0) return FALSE;
  59         else p = USS environ; /* RESTART from the beginning */
  60       else p++;
  61       }
  62     }
  63   store_reset(reset_point);
  64   }
  65 if (add_environment)
  66   {
  67   uschar * p;
  68   int sep = 0;
  69   const uschar * envlist = add_environment;
  70
  71   while ((p = string_nextinlist(&envlist, &sep, NULL, 0)))
  72     {
  73     DEBUG(D_expand) debug_printf("adding %s\n", p);
  74     putenv(CS p);
  75     }
  76   }
  77 #ifndef DISABLE_TLS
  78 tls_clean_env();
  79 #endif
  80
  81 store_pool = old_pool;
  82 return TRUE;
  83 }