/*
- 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
+ Copyright (C) 2002 by Jeremy Allison
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
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-/* 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
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.
struct message_rec {
int msg_version;
int msg_type;
- pid_t dest;
- pid_t src;
+ struct process_id dest;
+ struct process_id src;
size_t len;
};
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);
+ void (*fn)(int msg_type, struct process_id pid, void *buf, size_t len,
+ void *private_data);
+ void *private_data;
} *dispatch_fns;
/****************************************************************************
- Notifications come in as signals.
+ Free global objects.
****************************************************************************/
-static void sig_usr1(void)
+void gfree_messages(void)
{
- received_signal = 1;
- sys_select_signal();
+ struct dispatch_fns *dfn, *next;
+
+ /* delete the dispatch_fns list */
+ dfn = dispatch_fns;
+ while( dfn ) {
+ next = dfn->next;
+ DLIST_REMOVE(dispatch_fns, dfn);
+ SAFE_FREE(dfn);
+ dfn = next;
+ }
}
/****************************************************************************
- A useful function for testing the message system.
+ Notifications come in as signals.
****************************************************************************/
-void ping_message(int msg_type, pid_t src, void *buf, size_t len)
+static void sig_usr1(void)
{
- 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);
+ received_signal = 1;
+ sys_select_signal(SIGUSR1);
}
/****************************************************************************
- Return current debug level.
+ A useful function for testing the message system.
****************************************************************************/
-void debuglevel_message(int msg_type, pid_t src, void *buf, size_t len)
+static void ping_message(int msg_type, struct process_id src,
+ void *buf, size_t len, void *private_data)
{
- DEBUG(1,("INFO: Received REQ_DEBUGLEVEL message from PID %u\n",(unsigned int)src));
- message_send_pid(src, MSG_DEBUGLEVEL, DEBUGLEVEL_CLASS, sizeof(DEBUGLEVEL_CLASS), True);
+ const char *msg = buf ? (const char *)buf : "none";
+
+ DEBUG(1,("INFO: Received PING message from PID %s [%s]\n",
+ procid_str_static(&src), msg));
+ message_send_pid(src, MSG_PONG, buf, len, True);
}
/****************************************************************************
BOOL message_init(void)
{
- if (tdb) return True;
+ sec_init();
+
+ if (tdb)
+ return True;
tdb = tdb_open_log(lock_path("messages.tdb"),
0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
CatchSignal(SIGUSR1, SIGNAL_CAST sig_usr1);
- message_register(MSG_PING, ping_message);
- message_register(MSG_REQ_DEBUGLEVEL, debuglevel_message);
+ message_register(MSG_PING, ping_message, NULL);
+
+ /* Register some debugging related messages */
+
+ register_msg_pool_usage();
+ register_dmalloc_msgs();
return True;
}
Form a static tdb key from a pid.
******************************************************************/
-static TDB_DATA message_key_pid(pid_t pid)
+static TDB_DATA message_key_pid(struct process_id pid)
{
static char key[20];
TDB_DATA kbuf;
- slprintf(key, sizeof(key)-1, "PID/%d", (int)pid);
+ slprintf(key, sizeof(key)-1, "PID/%s", procid_str_static(&pid));
kbuf.dptr = (char *)key;
kbuf.dsize = strlen(key)+1;
then delete its record in the database.
****************************************************************************/
-static BOOL message_notify(pid_t pid)
+static BOOL message_notify(struct process_id procid)
{
- if (kill(pid, SIGUSR1) == -1) {
+ pid_t pid = procid.pid;
+ int ret;
+ uid_t euid = geteuid();
+
+ /*
+ * Doing kill with a non-positive pid causes messages to be
+ * sent to places we don't want.
+ */
+
+ SMB_ASSERT(pid > 0);
+
+ if (euid != 0) {
+ become_root_uid_only();
+ }
+
+ ret = kill(pid, SIGUSR1);
+
+ if (euid != 0) {
+ unbecome_root_uid_only();
+ }
+
+ if (ret == -1) {
if (errno == ESRCH) {
DEBUG(2,("pid %d doesn't exist - deleting messages record\n", (int)pid));
- tdb_delete(tdb, message_key_pid(pid));
+ tdb_delete(tdb, message_key_pid(procid));
} 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, void *buf, size_t len, BOOL duplicates_allowed)
+static BOOL message_send_pid_internal(struct process_id pid, int msg_type,
+ const void *buf, size_t len,
+ BOOL duplicates_allowed,
+ unsigned int timeout)
{
TDB_DATA kbuf;
TDB_DATA dbuf;
+ TDB_DATA old_dbuf;
struct message_rec rec;
- void *p;
+ char *ptr;
+ struct message_rec prec;
+
+ /* NULL pointer means implicit length zero. */
+ if (!buf) {
+ SMB_ASSERT(len == 0);
+ }
+
+ /*
+ * Doing kill with a non-positive pid causes messages to be
+ * sent to places we don't want.
+ */
+
+ SMB_ASSERT(procid_to_pid(&pid) > 0);
rec.msg_version = MESSAGE_VERSION;
rec.msg_type = msg_type;
rec.dest = pid;
- rec.src = sys_getpid();
- rec.len = len;
+ rec.src = procid_self();
+ rec.len = buf ? len : 0;
kbuf = message_key_pid(pid);
+ dbuf.dptr = (char *)SMB_MALLOC(len + sizeof(rec));
+ if (!dbuf.dptr)
+ return False;
+
+ memcpy(dbuf.dptr, &rec, sizeof(rec));
+ if (len > 0 && buf)
+ memcpy((void *)((char*)dbuf.dptr+sizeof(rec)), buf, len);
+
+ dbuf.dsize = len + sizeof(rec);
+
+ if (duplicates_allowed) {
+
+ /* If duplicates are allowed we can just append the message and return. */
+
+ /* lock the record for the destination */
+ if (timeout) {
+ if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+ DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
+ return False;
+ }
+ } else {
+ if (tdb_chainlock(tdb, kbuf) == -1) {
+ DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
+ return False;
+ }
+ }
+ tdb_append(tdb, kbuf, dbuf);
+ tdb_chainunlock(tdb, kbuf);
+
+ SAFE_FREE(dbuf.dptr);
+ errno = 0; /* paranoia */
+ return message_notify(pid);
+ }
+
/* lock the record for the destination */
- tdb_chainlock(tdb, kbuf);
+ if (timeout) {
+ if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+ DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
+ return False;
+ }
+ } else {
+ if (tdb_chainlock(tdb, kbuf) == -1) {
+ DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
+ return False;
+ }
+ }
- dbuf = tdb_fetch(tdb, kbuf);
+ old_dbuf = tdb_fetch(tdb, kbuf);
- if (!dbuf.dptr) {
+ if (!old_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;
+ tdb_chainunlock(tdb, kbuf);
+
+ SAFE_FREE(dbuf.dptr);
+ errno = 0; /* paranoia */
+ return message_notify(pid);
}
- 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), (char *)buf, len))) {
- DEBUG(10,("message_send_pid: discarding duplicate message.\n"));
- SAFE_FREE(dbuf.dptr);
- tdb_chainunlock(tdb, kbuf);
- return True;
- }
+ /* Not a new record. Check for duplicates. */
+
+ for(ptr = (char *)old_dbuf.dptr; ptr < old_dbuf.dptr + old_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))) {
+ tdb_chainunlock(tdb, kbuf);
+ DEBUG(10,("message_send_pid_internal: discarding duplicate message.\n"));
+ SAFE_FREE(dbuf.dptr);
+ SAFE_FREE(old_dbuf.dptr);
+ return True;
}
- memcpy(&prec, ptr, sizeof(prec));
- ptr += sizeof(rec) + prec.len;
}
+ 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);
+ tdb_append(tdb, kbuf, dbuf);
+ tdb_chainunlock(tdb, kbuf);
- SAFE_FREE(dbuf.dptr);
- dbuf.dptr = p;
- dbuf.dsize += len + sizeof(rec);
- tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+ SAFE_FREE(old_dbuf.dptr);
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;
+/****************************************************************************
+ Send a message to a particular pid - no timeout.
+****************************************************************************/
+
+BOOL message_send_pid(struct process_id pid, int msg_type, const void *buf, size_t len, BOOL duplicates_allowed)
+{
+ return message_send_pid_internal(pid, msg_type, buf, len, duplicates_allowed, 0);
+}
+
+/****************************************************************************
+ Send a message to a particular pid, with timeout in seconds.
+****************************************************************************/
+
+BOOL message_send_pid_with_timeout(struct process_id pid, int msg_type, const void *buf, size_t len,
+ BOOL duplicates_allowed, unsigned int timeout)
+{
+ return message_send_pid_internal(pid, msg_type, buf, len, duplicates_allowed, timeout);
}
/****************************************************************************
- Retrieve the next message for the current process.
+ Count the messages pending for a particular pid. Expensive....
****************************************************************************/
-static BOOL message_recv(int *msg_type, pid_t *src, void **buf, size_t *len)
+unsigned int messages_pending_for_pid(struct process_id pid)
{
TDB_DATA kbuf;
TDB_DATA dbuf;
- struct message_rec rec;
+ char *buf;
+ unsigned int message_count = 0;
- kbuf = message_key_pid(sys_getpid());
+ kbuf = message_key_pid(pid);
- tdb_chainlock(tdb, kbuf);
-
dbuf = tdb_fetch(tdb, kbuf);
- if (dbuf.dptr == NULL || dbuf.dsize == 0) goto failed;
+ if (dbuf.dptr == NULL || dbuf.dsize == 0) {
+ SAFE_FREE(dbuf.dptr);
+ return 0;
+ }
- memcpy(&rec, dbuf.dptr, sizeof(rec));
+ for (buf = dbuf.dptr; dbuf.dsize > sizeof(struct message_rec);) {
+ struct message_rec rec;
+ memcpy(&rec, buf, sizeof(rec));
+ buf += (sizeof(rec) + rec.len);
+ dbuf.dsize -= (sizeof(rec) + rec.len);
+ message_count++;
+ }
+
+ SAFE_FREE(dbuf.dptr);
+ return message_count;
+}
+
+/****************************************************************************
+ Retrieve all messages for the current process.
+****************************************************************************/
+
+static BOOL retrieve_all_messages(char **msgs_buf, size_t *total_len)
+{
+ TDB_DATA kbuf;
+ TDB_DATA dbuf;
+ TDB_DATA null_dbuf;
+
+ ZERO_STRUCT(null_dbuf);
+
+ *msgs_buf = NULL;
+ *total_len = 0;
+
+ kbuf = message_key_pid(pid_to_procid(sys_getpid()));
+
+ if (tdb_chainlock(tdb, kbuf) == -1)
+ return False;
+
+ dbuf = tdb_fetch(tdb, kbuf);
+ /*
+ * Replace with an empty record to keep the allocated
+ * space in the tdb.
+ */
+ tdb_store(tdb, kbuf, null_dbuf, TDB_REPLACE);
+ tdb_chainunlock(tdb, kbuf);
+
+ if (dbuf.dptr == NULL || dbuf.dsize == 0) {
+ SAFE_FREE(dbuf.dptr);
+ return False;
+ }
+
+ *msgs_buf = dbuf.dptr;
+ *total_len = dbuf.dsize;
+
+ return True;
+}
+
+/****************************************************************************
+ Parse out the next message for the current process.
+****************************************************************************/
+
+static BOOL message_recv(char *msgs_buf, size_t total_len, int *msg_type,
+ struct process_id *src, char **buf, size_t *len)
+{
+ struct message_rec rec;
+ char *ret_buf = *buf;
+
+ *buf = NULL;
+ *len = 0;
+
+ if (total_len - (ret_buf - msgs_buf) < sizeof(rec))
+ return False;
+
+ memcpy(&rec, ret_buf, sizeof(rec));
+ ret_buf += sizeof(rec);
if (rec.msg_version != MESSAGE_VERSION) {
DEBUG(0,("message version %d received (expected %d)\n", rec.msg_version, MESSAGE_VERSION));
- goto failed;
+ return False;
}
if (rec.len > 0) {
- (*buf) = (void *)malloc(rec.len);
- if (!(*buf)) goto failed;
-
- memcpy(*buf, dbuf.dptr+sizeof(rec), rec.len);
- } else {
- *buf = NULL;
+ if (total_len - (ret_buf - msgs_buf) < rec.len)
+ return False;
}
*len = rec.len;
*msg_type = rec.msg_type;
*src = rec.src;
+ *buf = ret_buf;
- 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);
- 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.
+ 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_dispatch(void)
{
int msg_type;
- pid_t src;
- void *buf;
- size_t len;
- struct dispatch_fns *dfn;
+ struct process_id src;
+ char *buf;
+ char *msgs_buf;
+ size_t len, total_len;
+ int n_handled;
- if (!received_signal) return;
+ 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)) {
+ if (!retrieve_all_messages(&msgs_buf, &total_len))
+ return;
+
+ for (buf = msgs_buf; message_recv(msgs_buf, total_len, &msg_type, &src, &buf, &len); buf += len) {
+ struct dispatch_fns *dfn;
+
+ DEBUG(10,("message_dispatch: received msg_type=%d "
+ "src_pid=%u\n", msg_type,
+ (unsigned int) procid_to_pid(&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);
+ dfn->fn(msg_type, src,
+ len ? (void *)buf : NULL, len,
+ dfn->private_data);
+ n_handled++;
+ break;
}
}
- SAFE_FREE(buf);
+ if (!n_handled) {
+ DEBUG(5,("message_dispatch: warning: no handler registed for "
+ "msg_type %d in pid %u\n",
+ msg_type, (unsigned int)sys_getpid()));
+ }
}
+ SAFE_FREE(msgs_buf);
}
/****************************************************************************
- Register a dispatch 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_register(int msg_type,
- void (*fn)(int msg_type, pid_t pid, void *buf, size_t len))
+ void (*fn)(int msg_type, struct process_id pid,
+ void *buf, size_t len,
+ void *private_data),
+ void *private_data)
{
struct dispatch_fns *dfn;
- dfn = (struct dispatch_fns *)malloc(sizeof(*dfn));
+ for (dfn = dispatch_fns; dfn; dfn = dfn->next) {
+ if (dfn->msg_type == msg_type) {
+ dfn->fn = fn;
+ return;
+ }
+ }
+
+ dfn = SMB_MALLOC_P(struct dispatch_fns);
if (dfn != NULL) {
dfn->msg_type = msg_type;
dfn->fn = fn;
+ dfn->private_data = private_data;
DLIST_ADD(dispatch_fns, dfn);
}
if (dfn->msg_type == msg_type) {
DLIST_REMOVE(dispatch_fns, dfn);
SAFE_FREE(dfn);
+ return;
}
}
}
struct msg_all {
int msg_type;
- void *buf;
+ uint32 msg_flag;
+ const void *buf;
size_t len;
BOOL duplicates;
+ int n_sent;
};
/****************************************************************************
if (crec.cnum != -1)
return 0;
- /* if the msg send fails because the pid was not found (i.e. smbd died),
+ /* 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.*/
- 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 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));
+ DEBUG(2,("pid %s doesn't exist - deleting connections %d [%s]\n",
+ procid_str_static(&crec.pid),
+ crec.cnum, crec.name));
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.
+ *
+ * @retval 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;
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
+ return False;
+
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;
}
+
+/*
+ * Block and unblock receiving of messages. Allows removal of race conditions
+ * when doing a fork and changing message disposition.
+ */
+
+void message_block(void)
+{
+ BlockSignals(True, SIGUSR1);
+}
+
+void message_unblock(void)
+{
+ BlockSignals(False, SIGUSR1);
+}
+/** @} **/
git.samba.org / samba.git / blobdiff