Re: [Qemu-devel] [PATCH V3] gdbstub: Fix handler for 'F' packet

["Alex Bennée" <alex.bennee@linaro.org>]

Sandra Loosemore <sandra@codesourcery.com> writes:

> 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>

Queued to gdbstub/next, thanks.

> ---
>  gdbstub.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/gdbstub.c b/gdbstub.c
> index b92ba59..3e8bcd0 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;
>      }


--
Alex Bennée