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Code Issues Releases Activity

gatserver: Refactor IO code 

The current GAtServer implementation had nasty corner cases where
multiple commands were issued on the same command line.  The
server_suspend had no effect and we ended up processing the second
command anyway, resulting in interesting side-effects or crashes.

This commit simply discards the rest of the read input if the server
starts processing a command.  Since we do not yet support command
abortion we also discard data that arrives when command is being
processed.
This commit is contained in:
Denis Kenzior 2011-08-14 22:54:03 -05:00
parent 7893cc3ef2
commit 5bd2b86ace
1 changed files with 22 additions and 25 deletions
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47
gatchat/gatserver.c
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@ -123,7 +123,6 @@ struct _GAtServer {
char *last_line; /* Last read line */
unsigned int cur_pos; /* Where we are on the line */
GAtServerResult last_result;
gboolean suspended;
gboolean final_sent;
gboolean final_async;
gboolean in_read_handler;
@ -131,7 +130,6 @@ struct _GAtServer {
static void server_wakeup_writer(GAtServer *server);
static void server_parse_line(GAtServer *server);
static void server_resume(GAtServer *server);
static struct ring_buffer *allocate_next(GAtServer *server)
{
@ -206,7 +204,7 @@ void g_at_server_send_final(GAtServer *server, GAtServerResult result)
server->final_sent = TRUE;
server->last_result = result;
if (result == G_AT_SERVER_RESULT_OK && server->suspended) {
if (result == G_AT_SERVER_RESULT_OK) {
if (server->final_async)
server_parse_line(server);
@ -219,8 +217,6 @@ void g_at_server_send_final(GAtServer *server, GAtServerResult result)
sprintf(buf, "%u", (unsigned int)result);
send_result_common(server, buf);
server_resume(server);
}
void g_at_server_send_ext_final(GAtServer *server, const char *result)
@ -228,8 +224,6 @@ void g_at_server_send_ext_final(GAtServer *server, const char *result)
server->final_sent = TRUE;
server->last_result = G_AT_SERVER_RESULT_EXT_ERROR;
send_result_common(server, result);
server_resume(server);
}
void g_at_server_send_intermediate(GAtServer *server, const char *result)
@ -810,11 +804,6 @@ static void server_parse_line(GAtServer *server)
server->final_async = FALSE;
if (pos == 0) {
server->suspended = TRUE;
g_at_io_set_read_handler(server->io, NULL, NULL);
}
while (pos < len) {
unsigned int consumed;
@ -847,7 +836,6 @@ static void server_parse_line(GAtServer *server)
return;
}
server_resume(server);
g_at_server_send_final(server, G_AT_SERVER_RESULT_OK);
}
@ -1008,6 +996,12 @@ 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;
/* We do not support command abortion, so ignore input */
if (p->final_async) {
ring_buffer_drain(rbuf, len);
return;
}
p->in_read_handler = TRUE;
while (p->io && (p->read_so_far < len)) {
@ -1025,10 +1019,10 @@ static void new_bytes(struct ring_buffer *rbuf, gpointer user_data)
wrap = len;
}
if (result == PARSER_RESULT_UNSURE)
switch (result) {
case PARSER_RESULT_UNSURE:
continue;
switch (result) {
case PARSER_RESULT_EMPTY_COMMAND:
/*
* According to section 5.2.4 and 5.6 of V250,
@ -1064,7 +1058,7 @@ static void new_bytes(struct ring_buffer *rbuf, gpointer user_data)
G_AT_SERVER_RESULT_OK);
break;
default:
case PARSER_RESULT_GARBAGE:
ring_buffer_drain(rbuf, p->read_so_far);
break;
}
@ -1072,6 +1066,18 @@ static void new_bytes(struct ring_buffer *rbuf, gpointer user_data)
len -= p->read_so_far;
wrap -= p->read_so_far;
p->read_so_far = 0;
/*
* Handle situations where we receive two command lines in
* one read, which should not be possible (and implies the
* earlier command should be canceled.
*
* e.g. AT+CMD1\rAT+CMD2
*/
if (result != PARSER_RESULT_GARBAGE) {
ring_buffer_drain(rbuf, len);
break;
}
}
p->in_read_handler = FALSE;
@ -1177,15 +1183,6 @@ static void server_wakeup_writer(GAtServer *server)
g_at_io_set_write_handler(server->io, can_write_data, server);
}
static void server_resume(GAtServer *server)
{
if (server->suspended == FALSE)
return;
server->suspended = FALSE;
g_at_io_set_read_handler(server->io, new_bytes, server);
}
static void at_notify_node_destroy(gpointer data)
{
struct at_command *node = data;