From b11448af2c3f6c9a49af0e4e70686f3ea59afc5d Mon Sep 17 00:00:00 2001 From: Volker Lendecke Date: Thu, 21 Nov 2013 21:05:29 +0100 Subject: [PATCH] smbd: Fix bug 10284 If we msg_read_send on a nonempty channel, we create one tevent_immediate. If we directly receive another message and from within the msg_read_send's tevent_req callback we immediately do another msg_read_send, we end up with two tevent_immediate events for msg_channel_trigger with just one incoming message. Test to follow. This patch simplifies msg_channel.c by removing the explicit immediate events. Instead, it relies on the implicit immediate event available via tevent_req_defer_callback. For messages received from tdb with a msg_read_send req pending, we directly finish that request without putting the message on the queue. Bug: https://bugzilla.samba.org/show_bug.cgi?id=10284 Signed-off-by: Volker Lendecke --- source3/lib/msg_channel.c | 100 ++++++++++++++------------------------------- 1 file changed, 31 insertions(+), 69 deletions(-) diff --git a/source3/lib/msg_channel.c b/source3/lib/msg_channel.c index 537b162..8e23fd4 100644 --- a/source3/lib/msg_channel.c +++ b/source3/lib/msg_channel.c @@ -41,9 +41,6 @@ static void msg_channel_init_got_ctdb(struct tevent_req *subreq); static void msg_channel_init_got_msg(struct messaging_context *msg, void *priv, uint32_t msg_type, struct server_id server_id, DATA_BLOB *data); -static void msg_channel_trigger(struct tevent_context *ev, - struct tevent_immediate *im, - void *priv); static int msg_channel_destructor(struct msg_channel *s); struct tevent_req *msg_channel_init_send(TALLOC_CTX *mem_ctx, @@ -157,6 +154,12 @@ fail: return err; } +struct msg_read_state { + struct tevent_context *ev; + struct msg_channel *channel; + struct messaging_rec *rec; +}; + static void msg_channel_init_got_msg(struct messaging_context *msg, void *priv, uint32_t msg_type, struct server_id server_id, @@ -167,7 +170,6 @@ static void msg_channel_init_got_msg(struct messaging_context *msg, struct messaging_rec *rec; struct messaging_rec **msgs; size_t num_msgs; - struct tevent_immediate *im; rec = talloc(s, struct messaging_rec); if (rec == NULL) { @@ -184,6 +186,19 @@ static void msg_channel_init_got_msg(struct messaging_context *msg, } rec->buf.length = data->length; + if (s->pending_req != NULL) { + struct tevent_req *req = s->pending_req; + struct msg_read_state *state = tevent_req_data( + req, struct msg_read_state); + + s->pending_req = NULL; + + state->rec = talloc_move(state, &rec); + tevent_req_defer_callback(req, s->ev); + tevent_req_done(req); + return; + } + num_msgs = talloc_array_length(s->msgs); msgs = talloc_realloc(s, s->msgs, struct messaging_rec *, num_msgs+1); if (msgs == NULL) { @@ -192,28 +207,11 @@ static void msg_channel_init_got_msg(struct messaging_context *msg, s->msgs = msgs; s->msgs[num_msgs] = talloc_move(s->msgs, &rec); - if (s->pending_req == NULL) { - return; - } - - im = tevent_create_immediate(s); - if (im == NULL) { - goto fail; - } - tevent_schedule_immediate(im, s->ev, msg_channel_trigger, s); return; fail: TALLOC_FREE(rec); } -struct msg_read_state { - struct tevent_context *ev; - struct tevent_req *req; - struct msg_channel *channel; - struct messaging_rec *rec; -}; - -static int msg_read_state_destructor(struct msg_read_state *s); static void msg_read_got_ctdb(struct tevent_req *subreq); struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx, @@ -221,7 +219,6 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx, struct msg_channel *channel) { struct tevent_req *req; - struct tevent_immediate *im; struct msg_read_state *state; void *msg_tdb_event; size_t num_msgs; @@ -231,28 +228,28 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx, return NULL; } state->ev = ev; - state->req = req; state->channel = channel; if (channel->pending_req != NULL) { tevent_req_error(req, EBUSY); return tevent_req_post(req, ev); } - channel->pending_req = req; - channel->ev = ev; - talloc_set_destructor(state, msg_read_state_destructor); num_msgs = talloc_array_length(channel->msgs); if (num_msgs != 0) { - im = tevent_create_immediate(channel->ev); - if (tevent_req_nomem(im, req)) { - return tevent_req_post(req, ev); - } - tevent_schedule_immediate(im, channel->ev, msg_channel_trigger, - channel); - return req; + state->rec = talloc_move(state, &channel->msgs[0]); + memmove(channel->msgs, channel->msgs+1, + sizeof(struct messaging_rec *) * (num_msgs-1)); + channel->msgs = talloc_realloc( + channel, channel->msgs, struct messaging_rec *, + num_msgs - 1); + tevent_req_done(req); + return tevent_req_post(req, ev); } + channel->pending_req = req; + channel->ev = ev; + msg_tdb_event = messaging_tdb_event(state, channel->msg, ev); if (tevent_req_nomem(msg_tdb_event, req)) { return tevent_req_post(req, ev); @@ -271,42 +268,6 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx, return req; } -static int msg_read_state_destructor(struct msg_read_state *s) -{ - assert(s->channel->pending_req == s->req); - s->channel->pending_req = NULL; - return 0; -} - -static void msg_channel_trigger(struct tevent_context *ev, - struct tevent_immediate *im, - void *priv) -{ - struct msg_channel *channel; - struct tevent_req *req; - struct msg_read_state *state; - size_t num_msgs; - - channel = talloc_get_type_abort(priv, struct msg_channel); - req = channel->pending_req; - state = tevent_req_data(req, struct msg_read_state); - - talloc_set_destructor(state, NULL); - msg_read_state_destructor(state); - - num_msgs = talloc_array_length(channel->msgs); - assert(num_msgs > 0); - - state->rec = talloc_move(state, &channel->msgs[0]); - - memmove(channel->msgs, channel->msgs+1, - sizeof(struct messaging_rec *) * (num_msgs-1)); - channel->msgs = talloc_realloc( - channel, channel->msgs, struct messaging_rec *, num_msgs - 1); - - tevent_req_done(req); -} - static void msg_read_got_ctdb(struct tevent_req *subreq) { struct tevent_req *req = tevent_req_callback_data( @@ -368,5 +329,6 @@ int msg_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx, return err; } *prec = talloc_move(mem_ctx, &state->rec); + tevent_req_received(req); return 0; } -- 1.7.9.5