2012-06-05 12:17:02

by Johan Hedberg

[permalink] [raw]
Subject: [PATCH] gattrib: Fix command timeout handling

From: Johan Hedberg <[email protected]>

This patch fixes command timeout handling. Previously attrib_destroy was
explicitly called which ignored any reference holders. This patch fixes
the issue by first passing errors to command callbacks and after that
marking the GAttrib object as stale so no further operations can be
done.
---
This is an untested patch which should hopefully fix bluetoothd crashes
when we fail to receive a response to a command. I'm sending it to
linux-bluetooth in case someone can spot some obvious problem with it.
If there are no objections I'll complete testing of it during the next
24 hours and then apply it upstream.

attrib/att.c | 4 ++++
attrib/att.h | 2 ++
attrib/gattrib.c | 29 ++++++++++++++++++++++++++++-
3 files changed, 34 insertions(+), 1 deletions(-)

diff --git a/attrib/att.c b/attrib/att.c
index a3a8947..c8e2e1d 100644
--- a/attrib/att.c
+++ b/attrib/att.c
@@ -72,6 +72,10 @@ const char *att_ecode2str(uint8_t status)
return "Insufficient Resources to complete the request";
case ATT_ECODE_IO:
return "Internal application error: I/O";
+ case ATT_ECODE_TIMEOUT:
+ return "A timeout occured";
+ case ATT_ECODE_ABORTED:
+ return "The operation was aborted";
default:
return "Unexpected error code";
}
diff --git a/attrib/att.h b/attrib/att.h
index d12a7f2..8979c95 100644
--- a/attrib/att.h
+++ b/attrib/att.h
@@ -72,6 +72,8 @@
#define ATT_ECODE_INSUFF_RESOURCES 0x11
/* Application error */
#define ATT_ECODE_IO 0xFF
+#define ATT_ECODE_TIMEOUT 0xFE
+#define ATT_ECODE_ABORTED 0xFD

/* Characteristic Property bit field */
#define ATT_CHAR_PROPER_BROADCAST 0x01
diff --git a/attrib/gattrib.c b/attrib/gattrib.c
index 9886a92..29c3585 100644
--- a/attrib/gattrib.c
+++ b/attrib/gattrib.c
@@ -53,6 +53,7 @@ struct _GAttrib {
guint next_evt_id;
GDestroyNotify destroy;
gpointer destroy_user_data;
+ gboolean stale;
};

struct command {
@@ -252,8 +253,25 @@ gboolean g_attrib_set_destroy_function(GAttrib *attrib,
static gboolean disconnect_timeout(gpointer data)
{
struct _GAttrib *attrib = data;
+ struct command *c;

- attrib_destroy(attrib);
+ c = g_queue_pop_head(attrib->requests);
+ if (c == NULL)
+ goto done;
+
+ if (c->func)
+ c->func(ATT_ECODE_TIMEOUT, NULL, 0, c->user_data);
+
+ command_destroy(c);
+
+ while ((c = g_queue_pop_head(attrib->requests))) {
+ if (c->func)
+ c->func(ATT_ECODE_ABORTED, NULL, 0, c->user_data);
+ command_destroy(c);
+ }
+
+done:
+ attrib->stale = TRUE;

return FALSE;
}
@@ -268,6 +286,9 @@ static gboolean can_write_data(GIOChannel *io, GIOCondition cond,
GIOStatus iostat;
GQueue *queue;

+ if (attrib->stale)
+ return FALSE;
+
if (cond & (G_IO_HUP | G_IO_ERR | G_IO_NVAL))
return FALSE;

@@ -337,6 +358,9 @@ static gboolean received_data(GIOChannel *io, GIOCondition cond, gpointer data)
GIOStatus iostat;
gboolean norequests, noresponses;

+ if (attrib->stale)
+ return FALSE;
+
if (attrib->timeout_watch > 0) {
g_source_remove(attrib->timeout_watch);
attrib->timeout_watch = 0;
@@ -447,6 +471,9 @@ guint g_attrib_send(GAttrib *attrib, guint id, guint8 opcode,
struct command *c;
GQueue *queue;

+ if (attrib->stale)
+ return 0;
+
c = g_try_new0(struct command, 1);
if (c == NULL)
return 0;
--
1.7.7.6



2012-06-05 14:20:21

by Vinicius Costa Gomes

[permalink] [raw]
Subject: Re: [PATCH] gattrib: Fix command timeout handling

Hi Johan,

On 20:17 Tue 05 Jun, Johan Hedberg wrote:
> From: Johan Hedberg <[email protected]>
>
> This patch fixes command timeout handling. Previously attrib_destroy was
> explicitly called which ignored any reference holders. This patch fixes
> the issue by first passing errors to command callbacks and after that
> marking the GAttrib object as stale so no further operations can be
> done.
> ---
> This is an untested patch which should hopefully fix bluetoothd crashes
> when we fail to receive a response to a command. I'm sending it to
> linux-bluetooth in case someone can spot some obvious problem with it.
> If there are no objections I'll complete testing of it during the next
> 24 hours and then apply it upstream.

Looks fine to me as well.

On a side note, I took a look at how gatchat[1] (from ofono) does this, and
it gave me some ideas about how to simplify some things, I am thinking
mostly about the GAttrib destruction code path. And this "stale"
condition would be useful.


[snip]


Cheers,
--
Vinicius

[1] http://git.kernel.org/?p=network/ofono/ofono.git;a=blob;f=gatchat/gatio.c;hb=HEAD

2012-06-05 12:25:57

by Ganir, Chen

[permalink] [raw]
Subject: RE: [PATCH] gattrib: Fix command timeout handling

Johan,

> -----Original Message-----
> From: [email protected] [mailto:linux-bluetooth-
> [email protected]] On Behalf Of Johan Hedberg
> Sent: Tuesday, June 05, 2012 3:17 PM
> To: [email protected]
> Subject: [PATCH] gattrib: Fix command timeout handling
>
> From: Johan Hedberg <[email protected]>
>
> This patch fixes command timeout handling. Previously attrib_destroy
> was
> explicitly called which ignored any reference holders. This patch fixes
> the issue by first passing errors to command callbacks and after that
> marking the GAttrib object as stale so no further operations can be
> done.
> ---
> This is an untested patch which should hopefully fix bluetoothd crashes
> when we fail to receive a response to a command. I'm sending it to
> linux-bluetooth in case someone can spot some obvious problem with it.
> If there are no objections I'll complete testing of it during the next
> 24 hours and then apply it upstream.
>
> attrib/att.c | 4 ++++
> attrib/att.h | 2 ++
> attrib/gattrib.c | 29 ++++++++++++++++++++++++++++-
> 3 files changed, 34 insertions(+), 1 deletions(-)
>
> diff --git a/attrib/att.c b/attrib/att.c
> index a3a8947..c8e2e1d 100644
> --- a/attrib/att.c
> +++ b/attrib/att.c
> @@ -72,6 +72,10 @@ const char *att_ecode2str(uint8_t status)
> return "Insufficient Resources to complete the request";
> case ATT_ECODE_IO:
> return "Internal application error: I/O";
> + case ATT_ECODE_TIMEOUT:
> + return "A timeout occured";
> + case ATT_ECODE_ABORTED:
> + return "The operation was aborted";
> default:
> return "Unexpected error code";
> }
> diff --git a/attrib/att.h b/attrib/att.h
> index d12a7f2..8979c95 100644
> --- a/attrib/att.h
> +++ b/attrib/att.h
> @@ -72,6 +72,8 @@
> #define ATT_ECODE_INSUFF_RESOURCES 0x11
> /* Application error */
> #define ATT_ECODE_IO 0xFF
> +#define ATT_ECODE_TIMEOUT 0xFE
> +#define ATT_ECODE_ABORTED 0xFD
>
> /* Characteristic Property bit field */
> #define ATT_CHAR_PROPER_BROADCAST 0x01
> diff --git a/attrib/gattrib.c b/attrib/gattrib.c
> index 9886a92..29c3585 100644
> --- a/attrib/gattrib.c
> +++ b/attrib/gattrib.c
> @@ -53,6 +53,7 @@ struct _GAttrib {
> guint next_evt_id;
> GDestroyNotify destroy;
> gpointer destroy_user_data;
> + gboolean stale;
> };
>
> struct command {
> @@ -252,8 +253,25 @@ gboolean g_attrib_set_destroy_function(GAttrib
> *attrib,
> static gboolean disconnect_timeout(gpointer data)
> {
> struct _GAttrib *attrib = data;
> + struct command *c;
>
> - attrib_destroy(attrib);
> + c = g_queue_pop_head(attrib->requests);
> + if (c == NULL)
> + goto done;
> +
> + if (c->func)
> + c->func(ATT_ECODE_TIMEOUT, NULL, 0, c->user_data);
> +
> + command_destroy(c);
> +
> + while ((c = g_queue_pop_head(attrib->requests))) {
> + if (c->func)
> + c->func(ATT_ECODE_ABORTED, NULL, 0, c->user_data);
> + command_destroy(c);
> + }
> +
> +done:
> + attrib->stale = TRUE;
>
> return FALSE;
> }
> @@ -268,6 +286,9 @@ static gboolean can_write_data(GIOChannel *io,
> GIOCondition cond,
> GIOStatus iostat;
> GQueue *queue;
>
> + if (attrib->stale)
> + return FALSE;
> +
> if (cond & (G_IO_HUP | G_IO_ERR | G_IO_NVAL))
> return FALSE;
>
> @@ -337,6 +358,9 @@ static gboolean received_data(GIOChannel *io,
> GIOCondition cond, gpointer data)
> GIOStatus iostat;
> gboolean norequests, noresponses;
>
> + if (attrib->stale)
> + return FALSE;
> +
> if (attrib->timeout_watch > 0) {
> g_source_remove(attrib->timeout_watch);
> attrib->timeout_watch = 0;
> @@ -447,6 +471,9 @@ guint g_attrib_send(GAttrib *attrib, guint id,
> guint8 opcode,
> struct command *c;
> GQueue *queue;
>
> + if (attrib->stale)
> + return 0;
> +
> c = g_try_new0(struct command, 1);
> if (c == NULL)
> return 0;
> --
> 1.7.7.6
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-
> bluetooth" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html

Looks ok to me.

Chen Ganir.