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samba-mirror/source3/lib/messages.c
Andrew Tridgell 6f1f9f6d8d fixed a bug in message handling for code the change notify code
The change notify code registered a separate message handler for each
tree connect. This registration uses the global messaging context.

The messaging code would consider a 2nd registration for the same
messaging type as being an 'update' of the handler, rather than a new
handler. It also would only call the first handler in the linked list
for a given message type when dispatching messages.

This patch changes the messaging code to allow for multiple
registrations of the same message type, and allow for multiple calls
to different messaging handler for one incoming message.

This fixes the problem with the test_notify_tcon() test that I
recently committed to the S4 smbtorture
2009-03-10 16:45:45 +11:00

386 lines
10 KiB
C

/*
Unix SMB/CIFS implementation.
Samba internal messaging functions
Copyright (C) Andrew Tridgell 2000
Copyright (C) 2001 by Martin Pool
Copyright (C) 2002 by Jeremy Allison
Copyright (C) 2007 by Volker Lendecke
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
@defgroup messages Internal messaging framework
@{
@file messages.c
@brief Module for internal messaging between Samba daemons.
The idea is that if a part of Samba wants to do communication with
another Samba process then it will do a message_register() of a
dispatch function, and use message_send_pid() to send messages to
that process.
The dispatch function is given the pid of the sender, and it can
use that to reply by message_send_pid(). See ping_message() for a
simple example.
@caution Dispatch functions must be able to cope with incoming
messages on an *odd* byte boundary.
This system doesn't have any inherent size limitations but is not
very efficient for large messages or when messages are sent in very
quick succession.
*/
#include "includes.h"
#include "librpc/gen_ndr/messaging.h"
#include "librpc/gen_ndr/ndr_messaging.h"
struct messaging_callback {
struct messaging_callback *prev, *next;
uint32 msg_type;
void (*fn)(struct messaging_context *msg, void *private_data,
uint32_t msg_type,
struct server_id server_id, DATA_BLOB *data);
void *private_data;
};
/****************************************************************************
A useful function for testing the message system.
****************************************************************************/
static void ping_message(struct messaging_context *msg_ctx,
void *private_data,
uint32_t msg_type,
struct server_id src,
DATA_BLOB *data)
{
const char *msg = data->data ? (const char *)data->data : "none";
DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
procid_str_static(&src), msg));
messaging_send(msg_ctx, src, MSG_PONG, data);
}
/****************************************************************************
Register/replace a dispatch function for a particular message type.
JRA changed Dec 13 2006. Only one message handler now permitted per type.
*NOTE*: Dispatch functions must be able to cope with incoming
messages on an *odd* byte boundary.
****************************************************************************/
struct msg_all {
struct messaging_context *msg_ctx;
int msg_type;
uint32 msg_flag;
const void *buf;
size_t len;
int n_sent;
};
/****************************************************************************
Send one of the messages for the broadcast.
****************************************************************************/
static int traverse_fn(struct db_record *rec,
const struct connections_key *ckey,
const struct connections_data *crec,
void *state)
{
struct msg_all *msg_all = (struct msg_all *)state;
NTSTATUS status;
if (crec->cnum != -1)
return 0;
/* Don't send if the receiver hasn't registered an interest. */
if(!(crec->bcast_msg_flags & msg_all->msg_flag))
return 0;
/* If the msg send fails because the pid was not found (i.e. smbd died),
* the msg has already been deleted from the messages.tdb.*/
status = messaging_send_buf(msg_all->msg_ctx,
crec->pid, msg_all->msg_type,
(uint8 *)msg_all->buf, msg_all->len);
if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
/* If the pid was not found delete the entry from connections.tdb */
DEBUG(2,("pid %s doesn't exist - deleting connections %d [%s]\n",
procid_str_static(&crec->pid), crec->cnum,
crec->servicename));
rec->delete_rec(rec);
}
msg_all->n_sent++;
return 0;
}
/**
* Send a message to all smbd processes.
*
* It isn't very efficient, but should be OK for the sorts of
* applications that use it. When we need efficient broadcast we can add
* it.
*
* @param n_sent Set to the number of messages sent. This should be
* equal to the number of processes, but be careful for races.
*
* @retval True for success.
**/
bool message_send_all(struct messaging_context *msg_ctx,
int msg_type,
const void *buf, size_t len,
int *n_sent)
{
struct msg_all msg_all;
msg_all.msg_type = msg_type;
if (msg_type < 1000)
msg_all.msg_flag = FLAG_MSG_GENERAL;
else if (msg_type > 1000 && msg_type < 2000)
msg_all.msg_flag = FLAG_MSG_NMBD;
else if (msg_type > 2000 && msg_type < 2100)
msg_all.msg_flag = FLAG_MSG_PRINT_NOTIFY;
else if (msg_type > 2100 && msg_type < 3000)
msg_all.msg_flag = FLAG_MSG_PRINT_GENERAL;
else if (msg_type > 3000 && msg_type < 4000)
msg_all.msg_flag = FLAG_MSG_SMBD;
else if (msg_type > 4000 && msg_type < 5000)
msg_all.msg_flag = FLAG_MSG_DBWRAP;
else
return False;
msg_all.buf = buf;
msg_all.len = len;
msg_all.n_sent = 0;
msg_all.msg_ctx = msg_ctx;
connections_forall(traverse_fn, &msg_all);
if (n_sent)
*n_sent = msg_all.n_sent;
return True;
}
struct event_context *messaging_event_context(struct messaging_context *msg_ctx)
{
return msg_ctx->event_ctx;
}
struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
struct server_id server_id,
struct event_context *ev)
{
struct messaging_context *ctx;
NTSTATUS status;
if (!(ctx = TALLOC_ZERO_P(mem_ctx, struct messaging_context))) {
return NULL;
}
ctx->id = server_id;
ctx->event_ctx = ev;
status = messaging_tdb_init(ctx, ctx, &ctx->local);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0, ("messaging_tdb_init failed: %s\n",
nt_errstr(status)));
TALLOC_FREE(ctx);
return NULL;
}
#ifdef CLUSTER_SUPPORT
if (lp_clustering()) {
status = messaging_ctdbd_init(ctx, ctx, &ctx->remote);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("messaging_ctdb_init failed: %s\n",
nt_errstr(status)));
TALLOC_FREE(ctx);
return NULL;
}
}
#endif
messaging_register(ctx, NULL, MSG_PING, ping_message);
/* Register some debugging related messages */
register_msg_pool_usage(ctx);
register_dmalloc_msgs(ctx);
debug_register_msgs(ctx);
return ctx;
}
/*
* re-init after a fork
*/
NTSTATUS messaging_reinit(struct messaging_context *msg_ctx)
{
NTSTATUS status;
TALLOC_FREE(msg_ctx->local);
status = messaging_tdb_init(msg_ctx, msg_ctx, &msg_ctx->local);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0, ("messaging_tdb_init failed: %s\n",
nt_errstr(status)));
return status;
}
#ifdef CLUSTER_SUPPORT
TALLOC_FREE(msg_ctx->remote);
if (lp_clustering()) {
status = messaging_ctdbd_init(msg_ctx, msg_ctx,
&msg_ctx->remote);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("messaging_ctdb_init failed: %s\n",
nt_errstr(status)));
return status;
}
}
#endif
return NT_STATUS_OK;
}
/*
* Register a dispatch function for a particular message type. Allow multiple
* registrants
*/
NTSTATUS messaging_register(struct messaging_context *msg_ctx,
void *private_data,
uint32_t msg_type,
void (*fn)(struct messaging_context *msg,
void *private_data,
uint32_t msg_type,
struct server_id server_id,
DATA_BLOB *data))
{
struct messaging_callback *cb;
/*
* Only one callback per type
*/
for (cb = msg_ctx->callbacks; cb != NULL; cb = cb->next) {
/* we allow a second registration of the same message
type if it has a different private pointer. This is
needed in, for example, the internal notify code,
which creates a new notify context for each tree
connect, and expects to receive messages to each of
them. */
if (cb->msg_type == msg_type && private_data == cb->private_data) {
DEBUG(5,("Overriding messaging pointer for type %u - private_data=%p\n",
(unsigned)msg_type, private_data));
cb->fn = fn;
cb->private_data = private_data;
return NT_STATUS_OK;
}
}
if (!(cb = talloc(msg_ctx, struct messaging_callback))) {
return NT_STATUS_NO_MEMORY;
}
cb->msg_type = msg_type;
cb->fn = fn;
cb->private_data = private_data;
DLIST_ADD(msg_ctx->callbacks, cb);
return NT_STATUS_OK;
}
/*
De-register the function for a particular message type.
*/
void messaging_deregister(struct messaging_context *ctx, uint32_t msg_type,
void *private_data)
{
struct messaging_callback *cb, *next;
for (cb = ctx->callbacks; cb; cb = next) {
next = cb->next;
if ((cb->msg_type == msg_type)
&& (cb->private_data == private_data)) {
DEBUG(5,("Deregistering messaging pointer for type %u - private_data=%p\n",
(unsigned)msg_type, private_data));
DLIST_REMOVE(ctx->callbacks, cb);
TALLOC_FREE(cb);
}
}
}
/*
Send a message to a particular server
*/
NTSTATUS messaging_send(struct messaging_context *msg_ctx,
struct server_id server, uint32_t msg_type,
const DATA_BLOB *data)
{
#ifdef CLUSTER_SUPPORT
if (!procid_is_local(&server)) {
return msg_ctx->remote->send_fn(msg_ctx, server,
msg_type, data,
msg_ctx->remote);
}
#endif
return msg_ctx->local->send_fn(msg_ctx, server, msg_type, data,
msg_ctx->local);
}
NTSTATUS messaging_send_buf(struct messaging_context *msg_ctx,
struct server_id server, uint32_t msg_type,
const uint8 *buf, size_t len)
{
DATA_BLOB blob = data_blob_const(buf, len);
return messaging_send(msg_ctx, server, msg_type, &blob);
}
/*
Dispatch one messsaging_rec
*/
void messaging_dispatch_rec(struct messaging_context *msg_ctx,
struct messaging_rec *rec)
{
struct messaging_callback *cb, *next;
for (cb = msg_ctx->callbacks; cb != NULL; cb = next) {
next = cb->next;
if (cb->msg_type == rec->msg_type) {
cb->fn(msg_ctx, cb->private_data, rec->msg_type,
rec->src, &rec->buf);
/* we continue looking for matching messages
after finding one. This matters for
subsystems like the internal notify code
which register more than one handler for
the same message type */
}
}
return;
}
/** @} **/