12:19 a.m.
This patch fix an issue with AT parser in gatserver.
If an empty command is issued after AT, then 2 answers are sent. The parser can
also get in a bad state where next commands will not be handled. After that the
parser will get back on his feets. This is caused by reentrency:
new_bytes() calls g_at_server_send_final(), which in turns calls server_resume
which calls new_bytes() again synchronously.
Sample dialog follows:
ofonod[30720]: Server: < AT+CMER=3,0,0,1\r\n
ofonod[30720]: Server: > \r\nOK\r\n
ofonod[30720]: Server: < AT+CFUN\r\n
ofonod[30720]: Server: > \r\nERROR\r\n
ofonod[30720]: Server: < AT\r\n
ofonod[30720]: Server: > \r\nOK\r\n
ofonod[30720]: Server: < \r\n
ofonod[30720]: Server: > \r\nOK\r\n\r\nOK\r\n
<2 answers sent>
ofonod[30720]: Server: < AT+CFUN\r\n
ofonod[30720]: Server: > \r\nERROR\r\n
ofonod[30720]: Server: < \r\n
ofonod[30720]: Server: > \r\nOK\r\n
ofonod[30720]: Server: < AT+CFUN\r\n
<missing ERROR reply to CFUN>
ofonod[30720]: Server: < \r\n
ofonod[30720]: Server: > \r\nOK\r\n
Frédéric Dalleau (1):
gatchat: Fix reentrency issue with empty commands
gatchat/gatserver.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
4:02 p.m.
Hi Frédéric,
On 07/07/2011 09:19 AM, Frédéric Dalleau wrote:
This patch fix an issue with AT parser in gatserver.
If an empty command is issued after AT, then 2 answers are sent. The parser can
also get in a bad state where next commands will not be handled. After that the
parser will get back on his feets. This is caused by reentrency:
new_bytes() calls g_at_server_send_final(), which in turns calls server_resume
which calls new_bytes() again synchronously.
We should not try to set the read handler if it already set. Have you
tried adding:
if (server->suspended == FALSE)
return;
to server_resume()?
Regards,
-Denis
12:19 a.m.
New subject: [PATCH] gatchat: Fix reentrency issue with empty commands
Emulator response to empty command is sent twice
---
gatchat/gatserver.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/gatchat/gatserver.c b/gatchat/gatserver.c
index 3a996cb..a29e489 100644
--- a/gatchat/gatserver.c
+++ b/gatchat/gatserver.c
@@ -1008,6 +1008,9 @@ static void new_bytes(struct ring_buffer *rbuf, gpointer user_data)
unsigned char *buf = ring_buffer_read_ptr(rbuf, p->read_so_far);
enum ParserResult result;
+ if (p->in_read_handler)
+ return;
+
p->in_read_handler = TRUE;
while (p->io && (p->read_so_far < len)) {
--
1.7.1
12:44 a.m.
Hi Denis,
2011/7/7 Denis Kenzior <denkenz(a)gmail.com>:
Hi Frédéric,
On 07/07/2011 09:19 AM, Frédéric Dalleau wrote:
> This patch fix an issue with AT parser in gatserver.
>
> If an empty command is issued after AT, then 2 answers are sent. The parser can
> also get in a bad state where next commands will not be handled. After that the
> parser will get back on his feets. This is caused by reentrency:
> new_bytes() calls g_at_server_send_final(), which in turns calls server_resume
> which calls new_bytes() again synchronously.
>
We should not try to set the read handler if it already set. Have you
tried adding:
if (server->suspended == FALSE)
return;
I like the idea of this one, but it still exhibit an issue in the case of A/:
Server_parse_line suspends and resumes in the
same function.
Regards,
Frédéric
7:25 a.m.
Hi Frederic,
On 07/08/2011 09:44 AM, Dalleau, Frederic wrote:
Hi Denis,
2011/7/7 Denis Kenzior <denkenz(a)gmail.com>:
> Hi Frédéric,
>
> On 07/07/2011 09:19 AM, Frédéric Dalleau wrote:
>> This patch fix an issue with AT parser in gatserver.
>>
>> If an empty command is issued after AT, then 2 answers are sent. The parser can
>> also get in a bad state where next commands will not be handled. After that the
>> parser will get back on his feets. This is caused by reentrency:
>> new_bytes() calls g_at_server_send_final(), which in turns calls server_resume
>> which calls new_bytes() again synchronously.
>>
>
> We should not try to set the read handler if it already set. Have you
> tried adding:
>
> if (server->suspended == FALSE)
> return;
>
I like the idea of this one, but it still exhibit an issue in the case of A/:
Server_parse_line suspends and resumes in the
same function.
I think I fixed this one as well in commit 329f2d7. Let me know if you
encounter further problems.
Regards,
-Denis
4087
days inactive
4091
days old
4 comments
3 participants
participants (3)
-
Dalleau, Frederic -
Denis Kenzior -
Frédéric Dalleau