bk commit into 4.0 tree (thek:1.2184) BUG#23010

[kpettersson]

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4.0 repository of thek. When thek does a push these changes will
be propagated to the main repository and, within 24 hours after the
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ChangeSet@stripped, 2006-11-06 11:41:52+01:00, thek@stripped +2 -0
  Bug#23010 _my_b_read() passing illegal file handles to my_seek()
  - The io cache flag seek_not_done was not set properly in the 
    reinit_io_cache function call and this led my_seek to be called
    desipite an invalid file handle.
  - Added a test in reinit_io_cache to ensure we have a valid file 
    handle before setting seek_not_done flag.

  mysys/mf_iocache.c@stripped, 2006-11-06 11:41:51+01:00, thek@stripped +5 -1
    Added a test to only trigger my_seek function calls if we have
    a valid file descriptor. 

  mysys/my_seek.c@stripped, 2006-11-06 11:41:51+01:00, thek@stripped +5 -0
    Refactored incomplete condition into an assertion. This also ensures
    that variable newpos is initialized properly.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	thek
# Host:	kpdesk.mysql.com
# Root:	/home/thek/dev/bug23010/my40-bug23010

--- 1.40/mysys/mf_iocache.c	2006-11-06 11:41:54 +01:00
+++ 1.41/mysys/mf_iocache.c	2006-11-06 11:41:54 +01:00
@@ -313,7 +313,11 @@ my_bool reinit_io_cache(IO_CACHE *info, 
       if (info->type == READ_CACHE)
       {
 	info->write_end=info->write_buffer+info->buffer_length;
-	info->seek_not_done=1;
+        /*
+          Trigger a new seek only if we have a valid
+          file handle.
+        */
+        info->seek_not_done= (info->file >= 0);
       }
       info->end_of_file = ~(my_off_t) 0;
     }

--- 1.10/mysys/my_seek.c	2006-11-06 11:41:54 +01:00
+++ 1.11/mysys/my_seek.c	2006-11-06 11:41:54 +01:00
@@ -30,6 +30,11 @@ my_off_t my_seek(File fd, my_off_t pos, 
 		   whence, MyFlags));
   DBUG_ASSERT(pos != MY_FILEPOS_ERROR);		/* safety check */
 
+  /*
+    Make sure we are using a valid file descriptor
+  */
+  DBUG_ASSERT(fd >= 0);
+  
   newpos=lseek(fd, pos, whence);
   if (newpos == (os_off_t) -1)
   {