Merged revisions 74336 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r74336 | antoine.pitrou | 2009-08-06 22:18:29 +0200 (jeu., 06 août 2009) | 8 lines
Issue #6629: Fix a data corruption issue in the new `io` package, which could
occur when writing to a BufferedRandom object (e.g. a file opened in "rb+" or
"wb+" mode) after having buffered a certain amount of data for reading. This
bug was not present in the pure Python implementation.
Yes, this is a serious issue.
........
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 98f8413..d8b6471 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1757,6 +1757,19 @@
}
Py_CLEAR(res);
+ /* Adjust the raw stream position if it is away from the logical stream
+ position. This happens if the read buffer has been filled but not
+ modified (and therefore _bufferedwriter_flush_unlocked() didn't rewind
+ the raw stream by itself).
+ Fixes issue #6629.
+ */
+ n = RAW_OFFSET(self);
+ if (n != 0) {
+ if (_buffered_raw_seek(self, -n, 1) < 0)
+ goto error;
+ self->raw_pos -= n;
+ }
+
/* Then write buf itself. At this point the buffer has been emptied. */
remaining = buf.len;
written = 0;