1 files changed, 72 insertions, 0 deletions
diff --git a/src/environment.c b/src/environment.c
new file mode 100644
index 0000000..c394eb7
--- /dev/null
+++ b/src/environment.c
@@ -0,0 +1,72 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) Heiko Schlittermann 2016
+ * hs@schlittermann.de
+ * See the file NOTICE for conditions of use and distribution.
+ */
+
+#include "exim.h"
+
+extern char **environ;
+
+/* The cleanup_environment() function is used during the startup phase
+of the Exim process, right after reading the configurations main
+part, before any expansions take place. It retains the environment
+variables we trust (via the keep_environment option) and allows to
+set additional variables (via add_environment).
+
+Returns:    TRUE if successful
+            FALSE otherwise
+*/
+
+BOOL
+cleanup_environment()
+{
+if (!keep_environment || *keep_environment == '\0')
+  {
+  /* From: https://github.com/dovecot/core/blob/master/src/lib/env-util.c#L55
+  Try to clear the environment.
+  a) environ = NULL crashes on OS X.
+  b) *environ = NULL doesn't work on FreeBSD 7.0.
+  c) environ = emptyenv doesn't work on Haiku OS
+  d) environ = calloc() should work everywhere */
+
+  if (environ) *environ = NULL;
+
+  }
+else if (Ustrcmp(keep_environment, "*") != 0)
+  {
+  uschar **p;
+  if (environ) for (p = USS environ; *p; /* see below */)
+    {
+    /* It's considered broken if we do not find the '=', according to
+    Florian Weimer. For now we ignore such strings. unsetenv() would complain,
+    getenv() would complain. */
+    uschar * eqp = Ustrchr(*p, '=');
+
+    if (eqp)
+      {
+      uschar * name = string_copyn(*p, eqp - *p);
+
+      if (OK != match_isinlist(name, CUSS &keep_environment,
+          0, NULL, NULL, MCL_NOEXPAND, FALSE, NULL))
+        if (os_unsetenv(name) < 0) return FALSE;
+        else p = USS environ; /* RESTART from the beginning */
+      else p++;
+      store_reset(name);
+      }
+    }
+  }
+if (add_environment)
+  {
+    uschar * p;
+    int sep = 0;
+    const uschar * envlist = add_environment;
+
+    while ((p = string_nextinlist(&envlist, &sep, NULL, 0))) putenv(CS p);
+  }
+
+  return TRUE;
+}