Added bool_lax{} expansion operator, which uses Router condition logic to

determine whether or not a string is true.
Switch the multiple-condition logic to use bool_lax{}.
Add note where we combine multiple conditions regarding the memory leak.

2 files changed, 43 insertions, 10 deletions

diff --git a/src/src/expand.c b/src/src/expand.c
index e5daff1a8..9f9cbb7be 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/expand.c,v 1.106 2010/06/05 23:50:18 pdp Exp $ */
+/* $Cambridge: exim/src/src/expand.c,v 1.107 2010/06/07 08:23:20 pdp Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -247,6 +247,7 @@ static uschar *cond_table[] = {
   US">=",
   US"and",
   US"bool",
+  US"bool_lax",
   US"crypteq",
   US"def",
   US"eq",
@@ -289,6 +290,7 @@ enum {
   ECOND_NUM_GE,
   ECOND_AND,
   ECOND_BOOL,
+  ECOND_BOOL_LAX,
   ECOND_CRYPTEQ,
   ECOND_DEF,
   ECOND_STR_EQ,
@@ -734,6 +736,8 @@ or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 forced fail or lookup defer. All store used by the function can be released on
 exit.
 
+The actual false-value tests should be replicated for ECOND_BOOL_LAX.
+
 Arguments:
   condition     the condition string
   m1            text to be incorporated in panic error
@@ -2491,19 +2495,25 @@ switch(cond_type)
   interpretation, where general data can be used and only a few values
   map to FALSE.
   Note that readconf.c boolean matching, for boolean configuration options,
-  only matches true/yes/false/no. */
+  only matches true/yes/false/no.
+  The bool_lax{} condition matches the Router logic, which is much more
+  liberal. */
   case ECOND_BOOL:
+  case ECOND_BOOL_LAX:
     {
     uschar *sub_arg[1];
     uschar *t;
+    uschar *ourname;
     size_t len;
     BOOL boolvalue = FALSE;
     while (isspace(*s)) s++;
     if (*s != '{') goto COND_FAILED_CURLY_START;
-    switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, US"bool"))
+    ourname = cond_type == ECOND_BOOL_LAX ? US"bool_lax" : US"bool";
+    switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, ourname))
       {
-      case 1: expand_string_message = US"too few arguments or bracketing "
-        "error for bool";
+      case 1: expand_string_message = string_sprintf(
+                  "too few arguments or bracketing error for %s",
+                  ourname);
       /*FALLTHROUGH*/
       case 2:
       case 3: return NULL;
@@ -2512,15 +2522,25 @@ switch(cond_type)
     while (isspace(*t)) t++;
     len = Ustrlen(t);
     DEBUG(D_expand)
-      debug_printf("considering bool: %s\n", len ? t : US"<empty>");
+      debug_printf("considering %s: %s\n", ourname, len ? t : US"<empty>");
+    /* logic for the lax case from expand_check_condition(), which also does
+    expands, and the logic is both short and stable enough that there should
+    be no maintenance burden from replicating it. */
     if (len == 0)
       boolvalue = FALSE;
     else if (Ustrspn(t, "0123456789") == len)
+      {
       boolvalue = (Uatoi(t) == 0) ? FALSE : TRUE;
+      /* expand_check_condition only does a literal string "0" check */
+      if ((cond_type == ECOND_BOOL_LAX) && (len > 1))
+        boolvalue = TRUE;
+      }
     else if (strcmpic(t, US"true") == 0 || strcmpic(t, US"yes") == 0)
       boolvalue = TRUE;
     else if (strcmpic(t, US"false") == 0 || strcmpic(t, US"no") == 0)
       boolvalue = FALSE;
+    else if (cond_type == ECOND_BOOL_LAX)
+      boolvalue = TRUE;
     else
       {
       expand_string_message = string_sprintf("unrecognised boolean "
diff --git a/src/src/readconf.c b/src/src/readconf.c
index 6fd0dd8ea..6b11621e0 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/readconf.c,v 1.42 2010/06/07 07:09:10 pdp Exp $ */
+/* $Cambridge: exim/src/src/readconf.c,v 1.43 2010/06/07 08:23:20 pdp Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -1516,12 +1516,25 @@ switch (type)
       str_target = (uschar **)((uschar *)data_block + (long int)(ol->value));
     if (extra_condition)
       {
-      /* We already have a condition, we're conducting a crude hack to let multiple
-      condition rules be chained together, despite storing them in text form. */
+      /* We already have a condition, we're conducting a crude hack to let
+      multiple condition rules be chained together, despite storing them in
+      text form. */
       saved_condition = *str_target;
-      strtemp = string_sprintf("${if and{{bool{%s}}{bool{%s}}}}",
+      strtemp = string_sprintf("${if and{{bool_lax{%s}}{bool_lax{%s}}}}",
           saved_condition, sptr);
       *str_target = string_copy_malloc(strtemp);
+      /* TODO(pdp): there is a memory leak here when we set 3 or more
+      conditions; I still don't understand the store mechanism enough
+      to know what's the safe way to free content from an earlier store.
+      AFAICT, stores stack, so freeing an early stored item also stores
+      all data alloc'd after it.  If we knew conditions were adjacent,
+      we could survive that, but we don't.  So I *think* we need to take
+      another bit from opt_type to indicate "malloced"; this seems like
+      quite a hack, especially for this one case.  It also means that
+      we can't ever reclaim the store from the *first* condition.
+
+      Because we only do this once, near process start-up, I'm prepared to
+      let this slide for the time being, even though it rankles.  */
       }
     else
       {