Merged revisions 74338 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

................
  r74338 | antoine.pitrou | 2009-08-06 22:29:56 +0200 (jeu., 06 août 2009) | 14 lines

  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.
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1 files changed, 13 insertions, 0 deletions

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 @@ bufferedwriter_write(buffered *self, PyObject *args)
     }
     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;