1 files changed, 123 insertions, 0 deletions
diff --git a/src/routers/rf_get_munge_headers.c b/src/routers/rf_get_munge_headers.c
new file mode 100644
index 0000000..d304d11
--- /dev/null
+++ b/src/routers/rf_get_munge_headers.c
@@ -0,0 +1,123 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2021 - 2022 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#include "../exim.h"
+#include "rf_functions.h"
+
+
+/*************************************************
+*      Get additional headers for a router       *
+*************************************************/
+
+/* This function is called by routers to sort out the additional headers
+and header remove list for a particular address.
+
+Arguments:
+  addr           the input address
+  rblock         the router instance
+  extra_headers  points to where to hang the header chain
+  remove_headers points to where to hang the remove list
+
+Returns:         OK if no problem
+                 DEFER if expanding a string caused a deferment
+                   or a big disaster (e.g. expansion failure)
+*/
+
+int
+rf_get_munge_headers(address_item *addr, router_instance *rblock,
+  header_line **extra_headers, uschar **remove_headers)
+{
+/* Default is to retain existing headers */
+*extra_headers = addr->prop.extra_headers;
+
+if (rblock->extra_headers)
+  {
+  const uschar * list = rblock->extra_headers;
+  int sep = '\n';
+  uschar * s, * t;
+  int slen;
+
+  while ((s = string_nextinlist(&list, &sep, NULL, 0)))
+    if (!(s = expand_string(t = s)))
+      {
+      if (!f.expand_string_forcedfail)
+	{
+	addr->message = string_sprintf(
+	  "%s router failed to expand add_headers item \"%s\": %s",
+	  rblock->name, t, expand_string_message);
+	return DEFER;
+	}
+      }
+    else if ((slen = Ustrlen(s)) > 0)
+      {
+      /* Expand succeeded. Put extra headers at the start of the chain because
+      further down it may point to headers from other routers, which may be
+      shared with other addresses. The output function outputs them in reverse
+      order. */
+
+      header_line *  h = store_get(sizeof(header_line), GET_UNTAINTED);
+
+      /* We used to use string_sprintf() to add the newline if needed, but that
+      causes problems if the header line is exceedingly long (e.g. adding
+      something to a pathologically long line). So avoid it. */
+
+      if (s[slen-1] == '\n')
+	h->text = s;
+      else
+	{
+	h->text = store_get(slen+2, s);
+	memcpy(h->text, s, slen);
+	h->text[slen++] = '\n';
+	h->text[slen] = 0;
+	}
+
+      h->next = *extra_headers;
+      h->type = htype_other;
+      h->slen = slen;
+      *extra_headers = h;
+      }
+  }
+
+/* Default is to retain existing removes */
+*remove_headers = addr->prop.remove_headers;
+
+/* Expand items from colon-sep list separately, then build new list */
+if (rblock->remove_headers)
+  {
+  const uschar * list = rblock->remove_headers;
+  int sep = ':';
+  uschar * s, * t;
+  gstring * g = NULL;
+
+  if (*remove_headers)
+    g = string_cat(NULL, *remove_headers);
+
+  while ((s = string_nextinlist(&list, &sep, NULL, 0)))
+    if (!(s = expand_string(t = s)))
+      {
+      if (!f.expand_string_forcedfail)
+	{
+	addr->message = string_sprintf(
+	  "%s router failed to expand remove_headers item \"%s\": %s",
+	  rblock->name, t, expand_string_message);
+	return DEFER;
+	}
+      }
+    else if (*s)
+      g = string_append_listele(g, ':', s);
+
+  if (g)
+    *remove_headers = g->s;
+  }
+
+return OK;
+}
+
+/* vi: aw ai sw=2
+*/
+/* End of rf_get_munge_headers.c */