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[patch] Workaround gdbserver<7.7 for setfs [Re: [patch] Suggest newer gdbserver if it has no qXfer:exec-file:read]
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: gdb-patches at sourceware dot org, Gary Benson <gbenson at redhat dot com>
- Date: Thu, 24 Mar 2016 23:09:33 +0100
- Subject: [patch] Workaround gdbserver<7.7 for setfs [Re: [patch] Suggest newer gdbserver if it has no qXfer:exec-file:read]
- Authentication-results: sourceware.org; auth=none
- References: <20160319201842 dot GA16540 at host1 dot jankratochvil dot net> <56F13963 dot 9040204 at redhat dot com> <20160322131604 dot GA24312 at host1 dot jankratochvil dot net> <56F14F1E dot 5010606 at redhat dot com> <20160323211547 dot GA17400 at host1 dot jankratochvil dot net>
On Wed, 23 Mar 2016 22:15:47 +0100, Jan Kratochvil wrote:
> With current FSF GDB HEAD and old FSF gdbserver I expected I could do:
> gdb -ex 'file target:/root/redhat/threadit' -ex 'target remote :1234'
> (supplying that unsupported qXfer:exec-file:read by "file")
> But that does not work because:
> Sending packet: $vFile:setfs:0#bf...Packet received: OK
> Packet vFile:setfs (hostio-setfs) is supported
> ...
> Sending packet: $vFile:setfs:104#24...Packet received: OK
> "target:/root/redhat/threadit": could not open as an executable file: Invalid argument
>
> GDB documentation says:
> The valid responses to Host I/O packets are:
> An empty response indicates that this operation is not recognized.
>
> OT: I do not see why "empty response" is response "OK" but apparently it is.
This "empty response" vs. "OK" was a bug in gdbserver < 7.7. It was fixed by:
commit e7f0d979dd5cc4f8b658df892e93db69d6d660b7
Author: Yao Qi <yao@codesourcery.com>
Date: Tue Dec 10 21:59:20 2013 +0800
Fix a bug in matching notifications.
Message-ID: <1386684626-11415-1-git-send-email-yao@codesourcery.com>
https://sourceware.org/ml/gdb-patches/2013-12/msg00373.html
2013-12-10 Yao Qi <yao@codesourcery.com>
* notif.c (handle_notif_ack): Return 0 if no notification
matches.
But I would prefer to make gdb compatible with gdbserver-7.6.1.
OK for check-in?
Thanks,
Jan
gdb/ChangeLog
2016-03-24 Jan Kratochvil <jan.kratochvil@redhat.com>
* remote.c (packet_ok): Add workaround for vFile:setfs.
diff --git a/gdb/remote.c b/gdb/remote.c
index af0a08a..be5cc09 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1311,7 +1311,14 @@ packet_ok (const char *buf, struct packet_config *config)
internal_error (__FILE__, __LINE__,
_("packet_ok: attempt to use a disabled packet"));
- result = packet_check_result (buf);
+ if (strcmp (config->name, "vFile:setfs") == 0 && strcmp (buf, "OK") == 0)
+ {
+ /* Workaround gdbserver < 7.7 before its fix from 2013-12-11. */
+ result = PACKET_UNKNOWN;
+ }
+ else
+ result = packet_check_result (buf);
+
switch (result)
{
case PACKET_OK: