diff options
Diffstat (limited to 'source3/lib/messages.c')
| -rw-r--r-- | source3/lib/messages.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/source3/lib/messages.c b/source3/lib/messages.c new file mode 100644 index 0000000000..30eef40ec9 --- /dev/null +++ b/source3/lib/messages.c @@ -0,0 +1,237 @@ +/* + Unix SMB/Netbios implementation. + Version 3.0 + Samba internal messaging functions + Copyright (C) Andrew Tridgell 2000 + + 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 + (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, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +/* this module is used for internal messaging between Samba daemons. */ + +#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; + enum message_type msg_type; + pid_t dest; + pid_t src; + size_t len; +}; + +/**************************************************************************** +notifications come in as signals +****************************************************************************/ +static void sig_usr1(void) +{ + received_signal = 1; + sys_select_signal(); +} + +/**************************************************************************** + Initialise the messaging functions. +****************************************************************************/ +BOOL message_init(void) +{ + if (tdb) return True; + + tdb = tdb_open(lock_path("messages.tdb"), + 0, TDB_CLEAR_IF_FIRST, + O_RDWR|O_CREAT,0600); + + if (!tdb) { + DEBUG(0,("ERROR: Failed to initialise messages database\n")); + return False; + } + + CatchSignal(SIGUSR1, sig_usr1); + + 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), "PID/%d", (int)pid); + + kbuf.dptr = (char *)key; + kbuf.dsize = sizeof(key); + 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) +{ + 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, enum message_type msg_type, void *buf, size_t len) +{ + 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; + + kbuf = message_key_pid(pid); + + /* lock the record for the destination */ + tdb_lockchain(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)); + memcpy(p+sizeof(rec), buf, len); + + dbuf.dptr = p; + dbuf.dsize = len + sizeof(rec); + tdb_store(tdb, kbuf, dbuf, TDB_REPLACE); + free(p); + goto ok; + } + + /* 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(p+dbuf.dsize, &rec, sizeof(rec)); + memcpy(p+dbuf.dsize+sizeof(rec), buf, len); + + dbuf.dptr = p; + dbuf.dsize += len + sizeof(rec); + tdb_store(tdb, kbuf, dbuf, TDB_REPLACE); + free(dbuf.dptr); + free(p); + + ok: + tdb_unlockchain(tdb, kbuf); + return message_notify(pid); + + failed: + tdb_unlockchain(tdb, kbuf); + return False; +} + + + +/**************************************************************************** +retrieve the next message for the current process +****************************************************************************/ +static BOOL message_recv(enum message_type *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_lockchain(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; + } + + (*buf) = (void *)malloc(rec.len); + if (!(*buf)) goto failed; + + memcpy(*buf, dbuf.dptr+sizeof(rec), rec.len); + *len = rec.len; + *msg_type = rec.msg_type; + *src = rec.src; + + memmove(dbuf.dptr, dbuf.dptr+sizeof(rec)+rec.len, dbuf.dsize - (sizeof(rec)+rec.len)); + dbuf.dsize -= sizeof(rec)+rec.len; + tdb_store(tdb, kbuf, dbuf, TDB_REPLACE); + + free(dbuf.dptr); + tdb_unlockchain(tdb, kbuf); + return True; + + failed: + tdb_unlockchain(tdb, kbuf); + return False; +} + + +/**************************************************************************** +receive and dispatch any messages pending for this process +****************************************************************************/ +void message_dispatch(void) +{ + enum message_type msg_type; + pid_t src; + void *buf; + size_t len; + + if (!received_signal) return; + received_signal = 0; + + while (message_recv(&msg_type, &src, &buf, &len)) { + switch (msg_type) { + case MSG_DEBUG: + debug_message(src, buf, len); + break; + default: + DEBUG(0,("Unknown message type %d from %d\n", msg_type, (int)src)); + break; + } + } +} |