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[commit/ob] remote: avoid undefined results in old thread extra info query
- From: Pedro Alves <pedro at codesourcery dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 8 Oct 2008 15:57:49 +0100
- Subject: [commit/ob] remote: avoid undefined results in old thread extra info query
I'm checking in the attached obvious patch.
We were parsing the reply starting at `rs->buf + 2', without checking
if the remote side supports the packet at all, possibly yielding
Here's what you usually get, if the remote doesn's support the query:
(top-gdb) p rs->buf
$2 = 0xbe4a60 ""
(top-gdb) p rs->buf + 2
$3 = 0xbe4a62 "meout"
That was "timeout" before being clobbered with the remote
replying '\0' --- meaning no support for this optional packet. By
chance, this string happens to have the property of not producing
any warning/error inside remote_unpack_thread_info_response. If it
had a parseable integer in it, it would --- I tripped on
this while implementing remote non-stop support.
2008-10-08 Pedro Alves <firstname.lastname@example.org>
* remote.c (remote_get_thread_info): If the remote doesn't support
the query, bail out.
gdb/remote.c | 4 ++++
1 file changed, 4 insertions(+)
--- src.orig/gdb/remote.c 2008-10-08 15:20:17.000000000 +0100
+++ src/gdb/remote.c 2008-10-08 15:24:00.000000000 +0100
@@ -1831,6 +1831,10 @@ remote_get_threadinfo (threadref *thread
pack_threadinfo_request (rs->buf, fieldset, threadid);
getpkt (&rs->buf, &rs->buf_size, 0);
+ if (rs->buf == '\0')
+ return 0;
result = remote_unpack_thread_info_response (rs->buf + 2,