summaryrefslogtreecommitdiffstats
path: root/source/lib/messages.c
diff options
context:
space:
mode:
Diffstat (limited to 'source/lib/messages.c')
-rw-r--r--source/lib/messages.c128
1 files changed, 113 insertions, 15 deletions
diff --git a/source/lib/messages.c b/source/lib/messages.c
index b4fd82139ea..518b7d51c1e 100644
--- a/source/lib/messages.c
+++ b/source/lib/messages.c
@@ -1,8 +1,8 @@
/*
- Unix SMB/Netbios implementation.
- Version 3.0
+ Unix SMB/CIFS implementation.
Samba internal messaging functions
Copyright (C) Andrew Tridgell 2000
+ Copyright (C) 2001 by Martin Pool
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
@@ -19,13 +19,22 @@
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-/* this module is used for internal messaging between Samba daemons.
+/**
+ @defgroups messages Internal messaging framework
+ @{
+ @file messages.c
+
+ This module is used 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.
+
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.
@@ -151,7 +160,8 @@ static BOOL message_notify(pid_t pid)
Send a message to a particular pid.
****************************************************************************/
-BOOL message_send_pid(pid_t pid, int msg_type, void *buf, size_t len, BOOL duplicates_allowed)
+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;
@@ -198,7 +208,7 @@ BOOL message_send_pid(pid_t pid, int msg_type, void *buf, size_t len, BOOL dupli
*/
if (!memcmp(ptr, &rec, sizeof(rec))) {
- if (!len || (len && !memcmp( ptr + sizeof(rec), (char *)buf, len))) {
+ 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);
@@ -303,6 +313,7 @@ void message_dispatch(void)
void *buf;
size_t len;
struct dispatch_fns *dfn;
+ int n_handled;
if (!received_signal) return;
@@ -311,12 +322,21 @@ void message_dispatch(void)
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 registed for "
+ "msg_type %d in pid%d\n",
+ msg_type, getpid()));
+ }
SAFE_FREE(buf);
}
}
@@ -366,9 +386,10 @@ void message_deregister(int msg_type)
struct msg_all {
int msg_type;
- void *buf;
+ const void *buf;
size_t len;
BOOL duplicates;
+ int n_sent;
};
/****************************************************************************
@@ -390,8 +411,9 @@ static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void
/* 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)) {
+ if (!message_send_pid(crec.pid, msg_all->msg_type,
+ msg_all->buf, msg_all->len,
+ msg_all->duplicates)) {
/* if the pid was not found delete the entry from connections.tdb */
if (errno == ESRCH) {
@@ -400,16 +422,26 @@ static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void
tdb_delete(the_tdb, kbuf);
}
}
+ msg_all->n_sent++;
return 0;
}
-/****************************************************************************
- This is a useful function for sending messages 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.
-****************************************************************************/
-
-BOOL message_send_all(TDB_CONTEXT *conn_tdb, int msg_type, void *buf, size_t len, BOOL duplicates_allowed)
+/**
+ * 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.
+ *
+ * @return True for success.
+ **/
+BOOL message_send_all(TDB_CONTEXT *conn_tdb, int msg_type,
+ const void *buf, size_t len,
+ BOOL duplicates_allowed,
+ int *n_sent)
{
struct msg_all msg_all;
@@ -417,7 +449,73 @@ BOOL message_send_all(TDB_CONTEXT *conn_tdb, int msg_type, void *buf, size_t len
msg_all.buf = buf;
msg_all.len = len;
msg_all.duplicates = duplicates_allowed;
+ msg_all.n_sent = 0;
tdb_traverse(conn_tdb, traverse_fn, &msg_all);
+ if (n_sent)
+ *n_sent = msg_all.n_sent;
return True;
}
+
+/** @} **/
+
+static VOLATILE sig_atomic_t gotalarm;
+
+/***************************************************************
+ Signal function to tell us we timed out.
+****************************************************************/
+
+static void gotalarm_sig(void)
+{
+ gotalarm = 1;
+}
+
+/*
+ lock the messaging tdb based on a string - this is used as a primitive form of mutex
+ between smbd instances.
+*/
+BOOL message_named_mutex(char *name, unsigned int timeout)
+{
+ TDB_DATA key;
+ int ret;
+
+ if (!message_init())
+ return False;
+
+ key.dptr = name;
+ key.dsize = strlen(name)+1;
+
+ if (timeout) {
+ gotalarm = 0;
+ CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
+ alarm(timeout);
+ }
+
+ ret = tdb_chainlock(tdb, key);
+
+ if (timeout) {
+ alarm(0);
+ CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
+ if (gotalarm)
+ return False;
+ }
+
+ if (ret == 0)
+ DEBUG(10,("message_named_mutex: got mutex for %s\n", name ));
+
+ return (ret == 0);
+}
+
+/*
+ unlock a named mutex
+*/
+void message_named_mutex_release(char *name)
+{
+ TDB_DATA key;
+
+ key.dptr = name;
+ key.dsize = strlen(name)+1;
+
+ tdb_chainunlock(tdb, key);
+ DEBUG(10,("message_named_mutex: released mutex for %s\n", name ));
+}
generated by cgit (git 2.34.1) at 2025-09-13 11:28:33 +0000