3 * Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
4 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
7 * Copyright (c) 1996 Regents of the University of Michigan.
10 * Redistribution and use in source and binary forms are permitted
11 * provided that this notice is preserved and that due credit is given
12 * to the University of Michigan at Ann Arbor. The name of the University
13 * may not be used to endorse or promote products derived from this
14 * software without specific prior written permission. This software
15 * is provided ``as is'' without express or implied warranty.
19 * rq.c - routines used to manage the queue of replication entries.
20 * An Rq (Replication queue) struct contains a linked list of Re
21 * (Replication entry) structures.
23 * Routines wishing to access the replication queue should do so through
24 * the Rq struct's member functions, e.g. rq->rq_gethead() and friends.
25 * For example, Re structs should be added to the queue by calling
26 * the rq_add() member function.
28 * Access to the queue is serialized by a mutex. Member functions which do
29 * not do their own locking should only be called after locking the queue
30 * using the rq_lock() member function. The queue should be unlocked with
31 * the rq_unlock() member function.
33 * Note that some member functions handle their own locking internally.
34 * Callers should not lock the queue before calling these functions.
35 * See the comment block for each function below.
44 #include <ac/stdlib.h>
45 #include <ac/string.h>
46 #include <ac/unistd.h> /* get ftruncate() */
48 #ifdef HAVE_SYS_TYPES_H
49 #include <sys/types.h>
60 * Lock the replication queue.
67 return( ldap_pvt_thread_mutex_lock( &rq->rq_mutex ));
72 * Unlock the replication queue.
79 return( ldap_pvt_thread_mutex_unlock( &rq->rq_mutex ));
85 * Return the head of the queue. Callers should lock the queue before
86 * calling this routine.
93 return( rq == NULL ? NULL : rq->rq_head );
98 * Return the next item in the queue. Callers should lock the queue before
99 * calling this routine.
109 return( re->re_getnext( re ));
115 * Delete the item at the head of the list. The queue should be locked
116 * by the caller before calling this routine.
130 savedhead = rq->rq_head;
131 if ( savedhead == NULL ) {
135 if ( savedhead->re_getrefcnt( savedhead ) != 0 ) {
136 Debug( LDAP_DEBUG_ANY, "Warning: attempt to delete when refcnt != 0\n",
141 rq->rq_head = rq->rq_head->re_getnext( rq->rq_head );
142 rc = savedhead->re_free( savedhead );
143 rq->rq_nre--; /* decrement count of Re's in queue */
149 * Add an entry to the tail of the replication queue. Locking is handled
150 * internally. When items are added to the queue, this routine wakes
151 * up any threads which are waiting for more work by signaling on the
152 * rq->rq_more condition variable.
166 /* Create a new Re */
167 if ( Re_init( &re ) < 0 ) {
172 /* parse buf and fill in the re struct */
173 if ( re->re_parse( re, buf ) < 0 ) {
179 /* Insert into queue */
180 if ( rq->rq_head == NULL ) {
185 rq->rq_tail->re_next = re;
188 /* set the sequence number */
190 if ( !wasempty && ( rq->rq_tail->re_timestamp == re->re_timestamp )) {
192 * Our new re has the same timestamp as the tail's timestamp.
193 * Increment the seq number in the tail and use it as our seq number.
195 re->re_seq = rq->rq_tail->re_seq + 1;
199 /* Increment count of items in queue */
201 /* wake up any threads waiting for more work */
202 ldap_pvt_thread_cond_broadcast( &rq->rq_more );
204 /* ... and unlock the queue */
212 * Garbage-collect the replication queue. Locking is handled internally.
220 Debug( LDAP_DEBUG_ANY, "Rq_gc: rq is NULL!\n", 0, 0, 0 );
224 while (( rq->rq_head != NULL ) &&
225 ( rq->rq_head->re_getrefcnt( rq->rq_head ) == 0 )) {
226 rq->rq_delhead( rq );
227 rq->rq_ndel++; /* increment count of deleted entries */
235 * For debugging: dump the contents of the replication queue to a file.
236 * Locking is handled internally.
248 Debug( LDAP_DEBUG_ANY, "Rq_dump: rq is NULL!\n", 0, 0, 0 );
252 if (unlink(SLURPD_DUMPFILE) == -1 && errno != ENOENT) {
253 Debug( LDAP_DEBUG_ANY, "Rq_dump: \"%s\" exists, and cannot unlink\n",
254 SLURPD_DUMPFILE, 0, 0 );
257 if (( tmpfd = open(SLURPD_DUMPFILE, O_CREAT|O_RDWR|O_EXCL, 0600)) == -1) {
258 Debug( LDAP_DEBUG_ANY, "Rq_dump: cannot open \"%s\" for write\n",
259 SLURPD_DUMPFILE, 0, 0 );
262 if (( fp = fdopen( tmpfd, "w" )) == NULL ) {
263 Debug( LDAP_DEBUG_ANY, "Rq_dump: cannot fdopen \"%s\" for write\n",
264 SLURPD_DUMPFILE, 0, 0 );
269 for ( re = rq->rq_gethead( rq ); re != NULL; re = rq->rq_getnext( re )) {
270 re->re_dump( re, fp );
279 * Write the contents of a replication queue to a file. Returns zero if
280 * successful, -1 if not. Handles queue locking internally. Callers should
281 * provide an open file pointer, which should refer to a locked file.
296 Debug( LDAP_DEBUG_ARGS, "re-write on-disk replication log\n",
301 fseek( fp, 0L, SEEK_SET ); /* Go to beginning of file */
304 for ( re = rq->rq_gethead( rq ); re != NULL; re = rq->rq_getnext( re )) {
305 if ( re->re_write( NULL, re, fp ) < 0 ) {
312 sglob->srpos = ftell( fp ); /* update replog file position */
313 /* and truncate to correct len */
314 if ( ftruncate( fileno( fp ), sglob->srpos ) < 0 ) {
315 Debug( LDAP_DEBUG_ANY, "Error truncating replication log: %s\n",
316 sys_errlist[ errno ], 0, 0 );
318 rq->rq_ndel = 0; /* reset count of deleted re's */
320 rq->rq_lasttrim = now; /* reset last trim time */
327 * Check to see if the private slurpd replication log needs trimming.
328 * The current criteria are:
329 * - The last trim was more than 5 minutes ago, *and*
330 * - We've finished with at least 50 replication log entries since the
331 * last time we re-wrote the replication log.
333 * Return 1 if replogfile should be trimmed, 0 if not.
334 * Any different policy should be implemented by replacing this function.
352 if ( now > ( rq->rq_lasttrim + TRIMCHECK_INTERVAL )) {
353 rc = ( rq->rq_ndel >= 50 );
363 * Return counts of Re structs in the queue.
379 if ( type == RQ_COUNT_ALL ) {
382 for ( re = rq->rq_gethead( rq ); re != NULL;
383 re = rq->rq_getnext( re )) {
384 if ( type == RQ_COUNT_NZRC ) {
385 if ( re->re_getrefcnt( re ) > 0 ) {
397 * Allocate and initialize an Rq object.
404 /* Instantiate the struct */
405 (*rq) = (Rq *) malloc( sizeof( Rq ));
410 /* Fill in all the function pointers */
411 (*rq)->rq_gethead = Rq_gethead;
412 (*rq)->rq_getnext = Rq_getnext;
413 (*rq)->rq_delhead = Rq_delhead;
414 (*rq)->rq_add = Rq_add;
415 (*rq)->rq_gc = Rq_gc;
416 (*rq)->rq_lock = Rq_lock;
417 (*rq)->rq_unlock = Rq_unlock;
418 (*rq)->rq_dump = Rq_dump;
419 (*rq)->rq_needtrim = Rq_needtrim;
420 (*rq)->rq_write = Rq_write;
421 (*rq)->rq_getcount = Rq_getcount;
423 /* Initialize private data */
424 ldap_pvt_thread_mutex_init( &((*rq)->rq_mutex) );
425 ldap_pvt_thread_cond_init( &((*rq)->rq_more) );
426 (*rq)->rq_head = NULL;
427 (*rq)->rq_tail = NULL;
430 (*rq)->rq_lasttrim = (time_t) 0L;