[Qemu-devel] [PATCH] gdbstub: Fix handler for 'F' packet

[Qemu-devel] [PATCH] gdbstub: Fix handler for 'F' packet

[Sandra Loosemore]

Handling of the 'F' packet has been broken since commit
4b20fab101b9e2d0fb47454209637a17fc7a13d5, which converted it to use
the new packet parsing infrastructure.  Per the GDB RSP specification

https://sourceware.org/gdb/current/onlinedocs/gdb/The-F-Reply-Packet.html

the second parameter may be omitted, but the rewritten implementation
was failing to recognize this case.  The result was that QEMU was
repeatedly resending the fileio request and ignoring GDB's replies of
successful completion.  This patch restores the behavior of the
previous code in allowing the errno parameter to be omitted and
passing 0 to the callback in that case.

Signed-off-by: Sandra Loosemore <sandra@codesourcery.com>
---
 gdbstub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/gdbstub.c b/gdbstub.c
index b92ba59..141568a 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1820,11 +1820,15 @@ static void handle_read_all_regs(GdbCmdContext *gdb_ctx, void *user_ctx)
 
 static void handle_file_io(GdbCmdContext *gdb_ctx, void *user_ctx)
 {
-    if (gdb_ctx->num_params >= 2 && gdb_ctx->s->current_syscall_cb) {
+    if (gdb_ctx->num_params >= 1 && gdb_ctx->s->current_syscall_cb) {
         target_ulong ret, err;
 
         ret = (target_ulong)gdb_ctx->params[0].val_ull;
-        err = (target_ulong)gdb_ctx->params[1].val_ull;
+        if (gdb_ctx->num_params >= 2 ) {
+            err = (target_ulong)gdb_ctx->params[1].val_ull;
+        } else {
+            err = 0;
+        }
         gdb_ctx->s->current_syscall_cb(gdb_ctx->s->c_cpu, ret, err);
         gdb_ctx->s->current_syscall_cb = NULL;
     }
-- 
2.8.1

Re: [Qemu-devel] [PATCH] gdbstub: Fix handler for 'F' packet

[no-reply]

Patchew URL: https://patchew.org/QEMU/20190827194849.7076-1-sandra@codesourcery.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Message-id: 20190827194849.7076-1-sandra@codesourcery.com
Type: series
Subject: [Qemu-devel] [PATCH] gdbstub: Fix handler for 'F' packet

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
0744b4b gdbstub: Fix handler for 'F' packet

=== OUTPUT BEGIN ===
ERROR: space prohibited before that close parenthesis ')'
#37: FILE: gdbstub.c:1827:
+        if (gdb_ctx->num_params >= 2 ) {

total: 1 errors, 0 warnings, 17 lines checked

Commit 0744b4b4b06b (gdbstub: Fix handler for 'F' packet) has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20190827194849.7076-1-sandra@codesourcery.com/testing.checkpatch/?type=message.
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