[lib] Fix the struct message LOOKUP function to be more robust
2008-02-28 Paul Jakma <paul.jakma@sun.com>
* log.c: (mes_lookup) Sowmini Varadhan diagnosed a problem where
this function can cause a NULL dereference, on lookups for unknown
indices, or messages with NULL strings. Can occur, e.g., debug
logging code when processing received messages. Fixed to accept a
pointer to a default string to be used if there is no match.
* log.h: LOOKUP adjusted to match
diff --git a/lib/log.c b/lib/log.c
index ff47cae..ce00bfb 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -752,14 +752,24 @@
}
/* Older/faster version of message lookup function, but requires caller to pass
- in the array size (instead of relying on a 0 key to terminate the search). */
+ * in the array size (instead of relying on a 0 key to terminate the search).
+ *
+ * The return value is the message string if found, or the 'none' pointer
+ * provided otherwise.
+ */
const char *
-mes_lookup (struct message *meslist, int max, int index)
+mes_lookup (struct message *meslist, int max, int index, const char *none)
{
+ int pos = index - meslist[0].key;
+
/* first check for best case: index is in range and matches the key
- value in that slot */
- if ((index >= 0) && (index < max) && (meslist[index].key == index))
- return meslist[index].str;
+ * value in that slot.
+ * NB: key numbering might be offset from 0. E.g. protocol constants
+ * often start at 1.
+ */
+ if ((pos >= 0) && (pos < max)
+ && (meslist[pos].key == index))
+ return meslist[pos].str;
/* fall back to linear search */
{
@@ -769,14 +779,17 @@
{
if (meslist->key == index)
{
+ const char *str = (meslist->str ? meslist->str : none);
+
zlog_debug ("message index %d [%s] found in position %d (max is %d)",
- index, meslist->str, i, max);
- return meslist->str;
+ index, str, i, max);
+ return str;
}
}
}
zlog_err("message index %d not found (max is %d)", index, max);
- return NULL;
+ assert (none);
+ return none;
}
/* Wrapper around strerror to handle case where it returns NULL. */