From ba2452f092acdb519043a23d72065d559a92ec21 Mon Sep 17 00:00:00 2001
From: "gbichot@dl145h.mysql.com" <>
Date: Fri, 23 Feb 2007 22:23:54 +0100
Subject: Fix for BUG#25628: "mysqlbinlog crashes while processing binary
 logs". mysqlbinlog prints all row-based events of a single statement as a
 single "BINLOG" statement containing the concatenation of those events. Big
 (i.e. >64k) concatenations of row-based events (e.g. Write_rows_log_event)
 caused mysqlbinlog's IO_CACHE to overflow to a temporary file but the
 IO_CACHE had not been inited with open_cached_file(), so it tried to create a
 temporary file in an uninitialized directory (thus failing to create, then to
 write; some OS errors were printed, and it finally segfaulted). After fixing
 this, it appeared that mysqlbinlog was printing only a piece of big
 concatenations of row-based events (it printed at most the size of the
 IO_CACHE's buffer i.e. 64k); that caused data loss at restore. We fix and
 test that. Last, mysqlbinlog's printouts looked a bit strange with the
 informative header (#-prefixed) of groupped Rows_log_event all on one line,
 so we insert \n. After that, a small bug in the --hexdump code appeared (only
 if the string to hex-print had its length a multiple of 16), we fix it.

---
 mysys/mf_iocache2.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

(limited to 'mysys')

diff --git a/mysys/mf_iocache2.c b/mysys/mf_iocache2.c
index 7b3393da4f5..a85f741bd67 100644
--- a/mysys/mf_iocache2.c
+++ b/mysys/mf_iocache2.c
@@ -50,7 +50,6 @@
 int
 my_b_copy_to_file(IO_CACHE *cache, FILE *file)
 {
-  byte buf[IO_SIZE];
   uint bytes_in_cache;
   DBUG_ENTER("my_b_copy_to_file");
 
@@ -58,19 +57,17 @@ my_b_copy_to_file(IO_CACHE *cache, FILE *file)
   if (reinit_io_cache(cache, READ_CACHE, 0L, FALSE, FALSE))
     DBUG_RETURN(1);
   bytes_in_cache= my_b_bytes_in_cache(cache);
-  while (bytes_in_cache > 0) {
-    uint const read_bytes= min(bytes_in_cache, sizeof(buf));
-    DBUG_PRINT("debug", ("Remaining %u bytes - Reading %u bytes",
-                         bytes_in_cache, read_bytes));
-    if (my_b_read(cache, buf, read_bytes))
-      DBUG_RETURN(1);
-    if (my_fwrite(file, buf, read_bytes, MYF(MY_WME | MY_NABP)) == (uint) -1)
+  do
+  {
+    if (my_fwrite(file, cache->read_pos, bytes_in_cache,
+                  MYF(MY_WME | MY_NABP)) == (uint) -1)
       DBUG_RETURN(1);
-    bytes_in_cache -= read_bytes;
-  }
+    cache->read_pos= cache->read_end;
+  } while ((bytes_in_cache= my_b_fill(cache)));
   DBUG_RETURN(0);
 }
 
+
 my_off_t my_b_append_tell(IO_CACHE* info)
 {
   /*
-- 
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