From dbed40ff5a0ea3d9e018218ec2fee9690d0055c2 Mon Sep 17 00:00:00 2001
From: Charles Kerr <charles@transmissionbt.com>
Date: Thu, 14 Oct 2010 04:21:14 +0000
Subject: [PATCH] (trunk libT) #3631 "crash in tr_ioFindFileLocation" -- add
 tracer messages to try & smoke out the error

---
 libtransmission/inout.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/libtransmission/inout.c b/libtransmission/inout.c
index f9ee10d29..54e2ff857 100644
--- a/libtransmission/inout.c
+++ b/libtransmission/inout.c
@@ -167,8 +167,7 @@ readOrWriteBytes( tr_session       * session,
 }
 
 static int
-compareOffsetToFile( const void * a,
-                     const void * b )
+compareOffsetToFile( const void * a, const void * b )
 {
     const uint64_t  offset = *(const uint64_t*)a;
     const tr_file * file = b;
@@ -188,10 +187,26 @@ tr_ioFindFileLocation( const tr_torrent * tor,
     const uint64_t  offset = tr_pieceOffset( tor, pieceIndex, pieceOffset, 0 );
     const tr_file * file;
 
+    assert( tr_isTorrent( tor ) );
+    assert( offset < tor->info.totalSize );
+
     file = bsearch( &offset,
                     tor->info.files, tor->info.fileCount, sizeof( tr_file ),
                     compareOffsetToFile );
 
+if( file == NULL ) {
+unsigned int i;
+fprintf( stderr, "%s", "transmission error\n" ); 
+fprintf( stderr, "pieceIndex %d\n", (int)pieceIndex );
+fprintf( stderr, "pieceOffset %d\n", (int)pieceOffset );
+fprintf( stderr, "couldn't find file matching offset %"PRIu64"\n", offset );
+fprintf( stderr, "total torrent size %"PRIu64"\n", tor->info.totalSize );
+fprintf( stderr, "%u files\n", (unsigned int)tor->info.fileCount );
+for( i=0; i<tor->info.fileCount; ++i ) fprintf( stderr, "file #%u offset %"PRIu64" length %"PRIu64"\n", i, tor->info.files[i].offset, tor->info.files[i].length );
+}
+
+    assert( file != NULL );
+
     *fileIndex = file - tor->info.files;
     *fileOffset = offset - file->offset;