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 2 of the License, or
+ 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,
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, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
- @defgroups messages Internal messaging framework
- @{
- @file messages.c
-
- This module is used for internal messaging between Samba daemons.
+ @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
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"
-
-/* the locking database handle */
-static TDB_CONTEXT *tdb;
-static int received_signal;
-
-/* change the message version with any incompatible changes in the protocol */
-#define MESSAGE_VERSION 1
-
-struct message_rec {
- int msg_version;
- int msg_type;
- pid_t dest;
- pid_t src;
- size_t len;
+#include "librpc/gen_ndr/messaging.h"
+#include "librpc/gen_ndr/ndr_messaging.h"
+#include "dbwrap.h"
+#include "serverid.h"
+#include "messages.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;
};
-/* we have a linked list of dispatch handlers */
-static struct dispatch_fns {
- struct dispatch_fns *next, *prev;
- int msg_type;
- void (*fn)(int msg_type, pid_t pid, void *buf, size_t len);
-} *dispatch_fns;
-
-/****************************************************************************
- Notifications come in as signals.
-****************************************************************************/
-
-static void sig_usr1(void)
-{
- received_signal = 1;
- sys_select_signal();
-}
-
/****************************************************************************
A useful function for testing the message system.
****************************************************************************/
-static void ping_message(int msg_type, pid_t src, void *buf, size_t len)
-{
- char *msg = buf ? buf : "none";
- DEBUG(1,("INFO: Received PING message from PID %u [%s]\n",(unsigned int)src, msg));
- message_send_pid(src, MSG_PONG, buf, len, True);
-}
-
-/****************************************************************************
- Initialise the messaging functions.
-****************************************************************************/
-
-BOOL message_init(void)
-{
- if (tdb) return True;
-
- tdb = tdb_open_log(lock_path("messages.tdb"),
- 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
- O_RDWR|O_CREAT,0600);
-
- if (!tdb) {
- DEBUG(0,("ERROR: Failed to initialise messages database\n"));
- return False;
- }
-
- CatchSignal(SIGUSR1, SIGNAL_CAST sig_usr1);
-
- message_register(MSG_PING, ping_message);
-
- return True;
-}
-
-/*******************************************************************
- Form a static tdb key from a pid.
-******************************************************************/
-
-static TDB_DATA message_key_pid(pid_t pid)
-{
- static char key[20];
- TDB_DATA kbuf;
-
- slprintf(key, sizeof(key)-1, "PID/%d", (int)pid);
-
- kbuf.dptr = (char *)key;
- kbuf.dsize = strlen(key)+1;
- return kbuf;
-}
-
-/****************************************************************************
- Notify a process that it has a message. If the process doesn't exist
- then delete its record in the database.
-****************************************************************************/
-
-static BOOL message_notify(pid_t pid)
-{
- /* Doing kill with a non-positive pid causes messages to be
- * sent to places we don't want. */
- SMB_ASSERT(pid > 0);
- if (kill(pid, SIGUSR1) == -1) {
- if (errno == ESRCH) {
- DEBUG(2,("pid %d doesn't exist - deleting messages record\n", (int)pid));
- tdb_delete(tdb, message_key_pid(pid));
- } else {
- DEBUG(2,("message to process %d failed - %s\n", (int)pid, strerror(errno)));
- }
- return False;
- }
- return True;
-}
-
-/****************************************************************************
- Send a message to a particular pid.
-****************************************************************************/
-
-BOOL message_send_pid(pid_t pid, int msg_type, const void *buf, size_t len,
- BOOL duplicates_allowed)
-{
- TDB_DATA kbuf;
- TDB_DATA dbuf;
- struct message_rec rec;
- void *p;
-
- rec.msg_version = MESSAGE_VERSION;
- rec.msg_type = msg_type;
- rec.dest = pid;
- rec.src = sys_getpid();
- rec.len = len;
-
- /* Doing kill with a non-positive pid causes messages to be
- * sent to places we don't want. */
- SMB_ASSERT(pid > 0);
-
- kbuf = message_key_pid(pid);
-
- /* lock the record for the destination */
- tdb_chainlock(tdb, kbuf);
-
- dbuf = tdb_fetch(tdb, kbuf);
-
- if (!dbuf.dptr) {
- /* its a new record */
- p = (void *)malloc(len + sizeof(rec));
- if (!p)
- goto failed;
-
- memcpy(p, &rec, sizeof(rec));
- if (len > 0)
- memcpy((void *)((char*)p+sizeof(rec)), buf, len);
-
- dbuf.dptr = p;
- dbuf.dsize = len + sizeof(rec);
- tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
- SAFE_FREE(p);
- goto ok;
- }
-
- if (!duplicates_allowed) {
- char *ptr;
- struct message_rec prec;
-
- for(ptr = (char *)dbuf.dptr; ptr < dbuf.dptr + dbuf.dsize; ) {
- /*
- * First check if the message header matches, then, if it's a non-zero
- * sized message, check if the data matches. If so it's a duplicate and
- * we can discard it. JRA.
- */
-
- if (!memcmp(ptr, &rec, sizeof(rec))) {
- if (!len || (len && !memcmp( ptr + sizeof(rec), buf, len))) {
- DEBUG(10,("message_send_pid: discarding duplicate message.\n"));
- SAFE_FREE(dbuf.dptr);
- tdb_chainunlock(tdb, kbuf);
- return True;
- }
- }
- memcpy(&prec, ptr, sizeof(prec));
- ptr += sizeof(rec) + prec.len;
- }
- }
-
- /* we're adding to an existing entry */
- p = (void *)malloc(dbuf.dsize + len + sizeof(rec));
- if (!p)
- goto failed;
-
- memcpy(p, dbuf.dptr, dbuf.dsize);
- memcpy((void *)((char*)p+dbuf.dsize), &rec, sizeof(rec));
- if (len > 0)
- memcpy((void *)((char*)p+dbuf.dsize+sizeof(rec)), buf, len);
-
- SAFE_FREE(dbuf.dptr);
- dbuf.dptr = p;
- dbuf.dsize += len + sizeof(rec);
- tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
- SAFE_FREE(dbuf.dptr);
-
- ok:
- tdb_chainunlock(tdb, kbuf);
- errno = 0; /* paranoia */
- return message_notify(pid);
-
- failed:
- tdb_chainunlock(tdb, kbuf);
- errno = 0; /* paranoia */
- return False;
-}
-
-/****************************************************************************
- Retrieve the next message for the current process.
-****************************************************************************/
-
-static BOOL message_recv(int *msg_type, pid_t *src, void **buf, size_t *len)
-{
- TDB_DATA kbuf;
- TDB_DATA dbuf;
- struct message_rec rec;
-
- kbuf = message_key_pid(sys_getpid());
-
- tdb_chainlock(tdb, kbuf);
-
- dbuf = tdb_fetch(tdb, kbuf);
- if (dbuf.dptr == NULL || dbuf.dsize == 0)
- goto failed;
-
- memcpy(&rec, dbuf.dptr, sizeof(rec));
-
- if (rec.msg_version != MESSAGE_VERSION) {
- DEBUG(0,("message version %d received (expected %d)\n", rec.msg_version, MESSAGE_VERSION));
- goto failed;
- }
-
- if (rec.len > 0) {
- (*buf) = (void *)malloc(rec.len);
- if (!(*buf))
- goto failed;
-
- memcpy(*buf, dbuf.dptr+sizeof(rec), rec.len);
- } else {
- *buf = NULL;
- }
-
- *len = rec.len;
- *msg_type = rec.msg_type;
- *src = rec.src;
-
- if (dbuf.dsize - (sizeof(rec)+rec.len) > 0)
- memmove(dbuf.dptr, dbuf.dptr+sizeof(rec)+rec.len, dbuf.dsize - (sizeof(rec)+rec.len));
- dbuf.dsize -= sizeof(rec)+rec.len;
-
- if (dbuf.dsize == 0)
- tdb_delete(tdb, kbuf);
- else
- tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
-
- SAFE_FREE(dbuf.dptr);
- tdb_chainunlock(tdb, kbuf);
- return True;
-
- failed:
- tdb_chainunlock(tdb, kbuf);
- SAFE_FREE(dbuf.dptr);
- return False;
-}
-
-/****************************************************************************
- Receive and dispatch any messages pending for this process.
- Notice that all dispatch handlers for a particular msg_type get called,
- so you can register multiple handlers for a message.
-****************************************************************************/
-
-void message_dispatch(void)
-{
- int msg_type;
- pid_t src;
- void *buf;
- size_t len;
- struct dispatch_fns *dfn;
- int n_handled;
-
- if (!received_signal) return;
-
- DEBUG(10,("message_dispatch: received_signal = %d\n", received_signal));
-
- received_signal = 0;
-
- while (message_recv(&msg_type, &src, &buf, &len)) {
- DEBUG(10,("message_dispatch: received msg_type=%d src_pid=%d\n",
- msg_type, (int) src));
- n_handled = 0;
- for (dfn = dispatch_fns; dfn; dfn = dfn->next) {
- if (dfn->msg_type == msg_type) {
- DEBUG(10,("message_dispatch: processing message of type %d.\n", msg_type));
- dfn->fn(msg_type, src, buf, len);
- n_handled++;
- }
- }
- if (!n_handled) {
- DEBUG(5,("message_dispatch: warning: no handlers registered for "
- "msg_type %d in pid %d\n",
- msg_type, sys_getpid()));
- }
- SAFE_FREE(buf);
- }
-}
-
-/****************************************************************************
- Register a dispatch function for a particular message type.
-****************************************************************************/
-
-void message_register(int msg_type,
- void (*fn)(int msg_type, pid_t pid, void *buf, size_t len))
+static void ping_message(struct messaging_context *msg_ctx,
+ void *private_data,
+ uint32_t msg_type,
+ struct server_id src,
+ DATA_BLOB *data)
{
- struct dispatch_fns *dfn;
-
- dfn = (struct dispatch_fns *)malloc(sizeof(*dfn));
-
- if (dfn != NULL) {
+ const char *msg = data->data ? (const char *)data->data : "none";
- ZERO_STRUCTPN(dfn);
-
- dfn->msg_type = msg_type;
- dfn->fn = fn;
-
- DLIST_ADD(dispatch_fns, dfn);
- }
- else {
-
- DEBUG(0,("message_register: Not enough memory. malloc failed!\n"));
- }
+ DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
+ procid_str_static(&src), msg));
+ messaging_send(msg_ctx, src, MSG_PONG, data);
}
/****************************************************************************
- De-register the function for a particular message type.
+ 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.
****************************************************************************/
-void message_deregister(int msg_type)
-{
- struct dispatch_fns *dfn, *next;
-
- for (dfn = dispatch_fns; dfn; dfn = next) {
- next = dfn->next;
- if (dfn->msg_type == msg_type) {
- DLIST_REMOVE(dispatch_fns, dfn);
- SAFE_FREE(dfn);
- }
- }
-}
-
struct msg_all {
+ struct messaging_context *msg_ctx;
int msg_type;
uint32 msg_flag;
const void *buf;
size_t len;
- BOOL duplicates;
int n_sent;
};
Send one of the messages for the broadcast.
****************************************************************************/
-static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
+static int traverse_fn(struct db_record *rec, const struct server_id *id,
+ uint32_t msg_flags, void *state)
{
- struct connections_data crec;
struct msg_all *msg_all = (struct msg_all *)state;
-
- if (dbuf.dsize != sizeof(crec))
- return 0;
-
- memcpy(&crec, dbuf.dptr, sizeof(crec));
-
- if (crec.cnum != -1)
- return 0;
+ NTSTATUS status;
/* Don't send if the receiver hasn't registered an interest. */
- if(!(crec.bcast_msg_flags & msg_all->msg_flag))
+ if((msg_flags & msg_all->msg_flag) == 0) {
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.*/
- if (!message_send_pid(crec.pid, msg_all->msg_type,
- msg_all->buf, msg_all->len,
- msg_all->duplicates)) {
+ status = messaging_send_buf(msg_all->msg_ctx, *id, 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 */
- if (errno == ESRCH) {
- DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
- (unsigned int)crec.pid, crec.cnum, crec.name));
- tdb_delete(the_tdb, kbuf);
- }
+ DEBUG(2, ("pid %s doesn't exist\n", procid_str_static(id)));
+
+ rec->delete_rec(rec);
}
msg_all->n_sent++;
return 0;
* @param n_sent Set to the number of messages sent. This should be
* equal to the number of processes, but be careful for races.
*
- * @return True for success.
+ * @retval True for success.
**/
-BOOL message_send_all(TDB_CONTEXT *conn_tdb, int msg_type,
+bool message_send_all(struct messaging_context *msg_ctx,
+ int msg_type,
const void *buf, size_t len,
- BOOL duplicates_allowed,
int *n_sent)
{
struct msg_all msg_all;
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 < 3000)
- msg_all.msg_flag = FLAG_MSG_PRINTING;
+ 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.duplicates = duplicates_allowed;
msg_all.n_sent = 0;
+ msg_all.msg_ctx = msg_ctx;
- tdb_traverse(conn_tdb, traverse_fn, &msg_all);
+ serverid_traverse(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(2, ("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(2, ("messaging_ctdb_init failed: %s\n",
+ nt_errstr(status)));
+ TALLOC_FREE(ctx);
+ return NULL;
+ }
+ }
+ ctx->id.vnn = get_my_vnn();
+#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;
+}
+
+struct server_id messaging_server_id(const struct messaging_context *msg_ctx)
+{
+ return msg_ctx->id;
+}
+
+/*
+ * re-init after a fork
+ */
+NTSTATUS messaging_reinit(struct messaging_context *msg_ctx,
+ struct server_id id)
+{
+ NTSTATUS status;
+
+ TALLOC_FREE(msg_ctx->local);
+
+ msg_ctx->id = id;
+
+ 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 messaging_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;
+}
+
/** @} **/
git.samba.org / kai / samba.git / blobdiff