2 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
4 * Copyright 1998-2007 The OpenLDAP Foundation.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted only as authorized by the OpenLDAP
11 * A copy of this license is available in file LICENSE in the
12 * top-level directory of the distribution or, alternatively, at
13 * <http://www.OpenLDAP.org/license.html>.
15 /* Portions Copyright (c) 1996 Regents of the University of Michigan.
16 * All rights reserved.
18 * Redistribution and use in source and binary forms are permitted
19 * provided that this notice is preserved and that due credit is given
20 * to the University of Michigan at Ann Arbor. The name of the University
21 * may not be used to endorse or promote products derived from this
22 * software without specific prior written permission. This software
23 * is provided ``as is'' without express or implied warranty.
26 * This work was originally developed by the University of Michigan
27 * (as part of U-MICH LDAP).
31 * rq.c - routines used to manage the queue of replication entries.
32 * An Rq (Replication queue) struct contains a linked list of Re
33 * (Replication entry) structures.
35 * Routines wishing to access the replication queue should do so through
36 * the Rq struct's member functions, e.g. rq->rq_gethead() and friends.
37 * For example, Re structs should be added to the queue by calling
38 * the rq_add() member function.
40 * Access to the queue is serialized by a mutex. Member functions which do
41 * not do their own locking should only be called after locking the queue
42 * using the rq_lock() member function. The queue should be unlocked with
43 * the rq_unlock() member function.
45 * Note that some member functions handle their own locking internally.
46 * Callers should not lock the queue before calling these functions.
47 * See the comment block for each function below.
56 #include <ac/stdlib.h>
57 #include <ac/string.h>
58 #include <ac/unistd.h> /* get ftruncate() */
60 #ifdef HAVE_SYS_TYPES_H
61 #include <sys/types.h>
71 * Lock the replication queue.
78 return( ldap_pvt_thread_mutex_lock( &rq->rq_mutex ));
83 * Unlock the replication queue.
90 return( ldap_pvt_thread_mutex_unlock( &rq->rq_mutex ));
96 * Return the head of the queue. Callers should lock the queue before
97 * calling this routine.
104 return( rq == NULL ? NULL : rq->rq_head );
109 * Return the next item in the queue. Callers should lock the queue before
110 * calling this routine.
120 return( re->re_getnext( re ));
126 * Delete the item at the head of the list. The queue should be locked
127 * by the caller before calling this routine.
141 savedhead = rq->rq_head;
142 if ( savedhead == NULL ) {
146 if ( savedhead->re_getrefcnt( savedhead ) != 0 ) {
147 Debug( LDAP_DEBUG_ANY, "Warning: attempt to delete when refcnt != 0\n",
152 rq->rq_head = rq->rq_head->re_getnext( rq->rq_head );
153 rc = savedhead->re_free( savedhead );
154 rq->rq_nre--; /* decrement count of Re's in queue */
160 * Add an entry to the tail of the replication queue. Locking is handled
161 * internally. When items are added to the queue, this routine wakes
162 * up any threads which are waiting for more work by signaling on the
163 * rq->rq_more condition variable.
177 /* Create a new Re */
178 if ( Re_init( &re ) < 0 ) {
183 /* parse buf and fill in the re struct */
184 if ( re->re_parse( re, buf ) < 0 ) {
190 /* Insert into queue */
191 if ( rq->rq_head == NULL ) {
196 rq->rq_tail->re_next = re;
199 /* set the sequence number */
201 if ( !wasempty && ( rq->rq_tail->re_timestamp == re->re_timestamp )) {
203 * Our new re has the same timestamp as the tail's timestamp.
204 * Increment the seq number in the tail and use it as our seq number.
206 re->re_seq = rq->rq_tail->re_seq + 1;
210 /* Increment count of items in queue */
212 /* wake up any threads waiting for more work */
213 ldap_pvt_thread_cond_broadcast( &rq->rq_more );
215 /* ... and unlock the queue */
223 * Garbage-collect the replication queue. Locking is handled internally.
231 Debug( LDAP_DEBUG_ANY, "Rq_gc: rq is NULL!\n", 0, 0, 0 );
235 while (( rq->rq_head != NULL ) &&
236 ( rq->rq_head->re_getrefcnt( rq->rq_head ) == 0 )) {
237 rq->rq_delhead( rq );
238 rq->rq_ndel++; /* increment count of deleted entries */
246 * For debugging: dump the contents of the replication queue to a file.
247 * Locking is handled internally.
259 Debug( LDAP_DEBUG_ANY, "Rq_dump: rq is NULL!\n", 0, 0, 0 );
263 if (unlink(SLURPD_DUMPFILE) == -1 && errno != ENOENT) {
264 Debug( LDAP_DEBUG_ANY, "Rq_dump: \"%s\" exists, and cannot unlink\n",
265 SLURPD_DUMPFILE, 0, 0 );
268 if (( tmpfd = open(SLURPD_DUMPFILE, O_CREAT|O_RDWR|O_EXCL, 0600)) == -1) {
269 Debug( LDAP_DEBUG_ANY, "Rq_dump: cannot open \"%s\" for write\n",
270 SLURPD_DUMPFILE, 0, 0 );
273 if (( fp = fdopen( tmpfd, "w" )) == NULL ) {
274 Debug( LDAP_DEBUG_ANY, "Rq_dump: cannot fdopen \"%s\" for write\n",
275 SLURPD_DUMPFILE, 0, 0 );
280 for ( re = rq->rq_gethead( rq ); re != NULL; re = rq->rq_getnext( re )) {
281 re->re_dump( re, fp );
290 * Write the contents of a replication queue to a file. Returns zero if
291 * successful, -1 if not. Handles queue locking internally. Callers should
292 * provide an open file pointer, which should refer to a locked file.
307 Debug( LDAP_DEBUG_ARGS, "re-write on-disk replication log\n",
312 fseek( fp, 0L, SEEK_SET ); /* Go to beginning of file */
315 for ( re = rq->rq_gethead( rq ); re != NULL; re = rq->rq_getnext( re )) {
316 if ( re->re_write( NULL, re, fp ) < 0 ) {
323 sglob->srpos = ftell( fp ); /* update replog file position */
324 /* and truncate to correct len */
325 if ( ftruncate( fileno( fp ), sglob->srpos ) < 0 ) {
326 Debug( LDAP_DEBUG_ANY, "Error truncating replication log: %s\n",
327 sys_errlist[ errno ], 0, 0 );
329 rq->rq_ndel = 0; /* reset count of deleted re's */
331 rq->rq_lasttrim = now; /* reset last trim time */
338 * Check to see if the private slurpd replication log needs trimming.
339 * The current criteria are:
340 * - The last trim was more than 5 minutes ago, *and*
341 * - We've finished with at least 50 replication log entries since the
342 * last time we re-wrote the replication log.
344 * Return 1 if replogfile should be trimmed, 0 if not.
345 * Any different policy should be implemented by replacing this function.
363 if ( now > ( rq->rq_lasttrim + TRIMCHECK_INTERVAL )) {
364 rc = ( rq->rq_ndel >= 50 );
374 * Return counts of Re structs in the queue.
390 if ( type == RQ_COUNT_ALL ) {
393 for ( re = rq->rq_gethead( rq ); re != NULL;
394 re = rq->rq_getnext( re )) {
395 if ( type == RQ_COUNT_NZRC ) {
396 if ( re->re_getrefcnt( re ) > 0 ) {
408 * Allocate and initialize an Rq object.
415 /* Instantiate the struct */
416 (*rq) = (Rq *) malloc( sizeof( Rq ));
421 /* Fill in all the function pointers */
422 (*rq)->rq_gethead = Rq_gethead;
423 (*rq)->rq_getnext = Rq_getnext;
424 (*rq)->rq_delhead = Rq_delhead;
425 (*rq)->rq_add = Rq_add;
426 (*rq)->rq_gc = Rq_gc;
427 (*rq)->rq_lock = Rq_lock;
428 (*rq)->rq_unlock = Rq_unlock;
429 (*rq)->rq_dump = Rq_dump;
430 (*rq)->rq_needtrim = Rq_needtrim;
431 (*rq)->rq_write = Rq_write;
432 (*rq)->rq_getcount = Rq_getcount;
434 /* Initialize private data */
435 ldap_pvt_thread_mutex_init( &((*rq)->rq_mutex) );
436 ldap_pvt_thread_cond_init( &((*rq)->rq_more) );
437 (*rq)->rq_head = NULL;
438 (*rq)->rq_tail = NULL;
441 (*rq)->rq_lasttrim = (time_t) 0L;