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[Qemu-devel] [PATCH] Parsing problem of gdb 'M' packet
From: |
Thomas Petazzoni |
Subject: |
[Qemu-devel] [PATCH] Parsing problem of gdb 'M' packet |
Date: |
Sat, 15 Jan 2005 17:12:13 +0100 |
User-agent: |
Mozilla Thunderbird 0.9 (X11/20041124) |
Hello,
I've found a problem in the code parsing the gdb 'M' packet. During gdb
remote sessions, I saw strange things when writing to memory :
============================================================
(gdb) print addr
$1 = 0
(gdb) set addr=12
(gdb) print addr
$2 = 49152
============================================================
So, I went into Qemu code, and found a problem in gdbstub.c. The format
of a 'M' packet is Maddr,length:XX... as stated on [1]. So the addr is
separated from the length using a comma, and the length from the data
using a colon.
However, the Qemu code assumed that all fields were seperated with a
comma, leading to wrong analysis of the data field.
The included one-line patch fixes the problem :
=============================================================
(gdb) print addr
$1 = 0
(gdb) set addr=12
(gdb) print addr
$2 = 12
=============================================================
Thomas
[1] http://sources.redhat.com/gdb/current/onlinedocs/gdb_33.html#SEC664
--
PETAZZONI Thomas - address@hidden
http://thomas.enix.org - Jabber: address@hidden
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Index: gdbstub.c
===================================================================
RCS file: /cvsroot/qemu/qemu/gdbstub.c,v
retrieving revision 1.22
diff -u -u -r1.22 gdbstub.c
--- gdbstub.c 3 Jan 2005 23:34:06 -0000 1.22
+++ gdbstub.c 15 Jan 2005 16:06:09 -0000
@@ -420,7 +420,7 @@
if (*p == ',')
p++;
len = strtoul(p, (char **)&p, 16);
- if (*p == ',')
+ if (*p == ':')
p++;
hextomem(mem_buf, p, len);
if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
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- [Qemu-devel] [PATCH] Parsing problem of gdb 'M' packet,
Thomas Petazzoni <=