From 3b58f9929f947f2c21a6bfe439d9b0819a9900fe Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Wed, 20 Feb 2008 23:58:48 +0000
Subject: [PATCH]  r18283@catbus:  nickm | 2008-02-20 18:58:31 -0500  Fix
 assertion when searching for a string in an empty chunk.

svn:r13634
---
 src/or/buffers.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/or/buffers.c b/src/or/buffers.c
index 1f0d64d4b3..8c5e2efca5 100644
--- a/src/or/buffers.c
+++ b/src/or/buffers.c
@@ -1021,15 +1021,19 @@ buf_find_pos_of_char(char ch, buf_pos_t *out)
   int pos;
   tor_assert(out);
   if (out->chunk) {
-    if (!(out->pos < (off_t)out->chunk->datalen)) {
-      log_warn(LD_BUG, "About to assert. %p, %d, %d, %p, %d.",
-               out, (int)out->pos,
-               (int)out->chunk_pos, out->chunk,
-               out->chunk?(int)out->chunk->datalen : (int)-1
-               );
+    if (out->chunk->datalen) {
       /*XXXX020 remove this once the bug it detects is fixed. */
+      if (!(out->pos < (off_t)out->chunk->datalen)) {
+        log_warn(LD_BUG, "About to assert. %p, %d, %d, %p, %d.",
+                 out, (int)out->pos,
+                 (int)out->chunk_pos, out->chunk,
+                 out->chunk?(int)out->chunk->datalen : (int)-1
+                 );
+      }
+      tor_assert(out->pos < (off_t)out->chunk->datalen);
+    } else {
+      tor_assert(out->pos == 0);
     }
-    tor_assert(out->pos < (off_t)out->chunk->datalen);
   }
   pos = out->pos;
   for (chunk = out->chunk; chunk; chunk = chunk->next) {