lock_ops.h
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 /* $Id$ */
 /*
  *
  * Copyright (C) 2001-2003 Fhg Fokus
  *
  * This file is part of ser, a free SIP server.
  *
  * ser 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
  *
  * For a license to use the ser software under conditions
  * other than those described here, or to purchase support for this
  * software, please contact iptel.org by e-mail at the following addresses:
  *    info@iptel.org
  *
  * ser 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 /*
  *   ser locking library
  *   WARNING: do not include this file directly, use instead locking.h
  *   (unless you don't need to alloc/dealloc locks)
  *
  *  2002-12-16  created by andrei
  *  2003-02-20  s/gen_lock_t/gen_lock_t/ to avoid a type conflict 
  *               on solaris  (andrei)
  *  2003-03-05  lock set support added for FAST_LOCK & SYSV (andrei)
  *  2003-03-06  removed *_alloc,*_dealloc & moved them to lock_alloc.h
  *              renamed locking.h to lock_ops.h (all this to solve
  *              the locking.h<->shm_mem.h interdependency) (andrei)
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  *  2003-03-10  lock set support added also for PTHREAD_MUTEX & POSIX_SEM
  *               (andrei)
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  *  2003-03-17  possible signal interruptions treated for sysv (andrei)
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  *
 Implements:
 
 	simple locks:
 	-------------
 	gen_lock_t* lock_init(gen_lock_t* lock); - inits the lock
 	void    lock_destroy(gen_lock_t* lock);  - removes the lock (e.g sysv rmid)
 	void    lock_get(gen_lock_t* lock);      - lock (mutex down)
 	void    lock_release(gen_lock_t* lock);  - unlock (mutex up)
 	
 	lock sets: [implemented only for FL & SYSV so far]
 	----------
 	lock_set_t* lock_set_init(lock_set_t* set);  - inits the lock set
 	void lock_set_destroy(lock_set_t* s);        - removes the lock set
 	void lock_set_get(lock_set_t* s, int i);     - locks sem i from the set
 	void lock_set_release(lock_set_t* s, int i)  - unlocks sem i from the set
 
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 WARNING: - lock_set_init may fail for large number of sems (e.g. sysv). 
          - signals are not treated! (some locks are "awakened" by the signals)
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 */
 
 #ifndef _lock_ops_h
 #define _lock_ops_h
 
 
 #ifdef FAST_LOCK
 #include "fastlock.h"
 
 typedef fl_lock_t gen_lock_t;
 
 
 #define lock_destroy(lock) /* do nothing */ 
 
 inline static gen_lock_t* lock_init(gen_lock_t* lock)
 {
 	init_lock(*lock);
 	return lock;
 }
 
 #define lock_get(lock) get_lock(lock)
 #define lock_release(lock) release_lock(lock)
 
 #elif defined USE_PTHREAD_MUTEX
 #include <pthread.h>
 
 typedef pthread_mutex_t gen_lock_t;
 
 #define lock_destroy(lock) /* do nothing */ 
 
 inline static gen_lock_t* lock_init(gen_lock_t* lock)
 {
 	if (pthread_mutex_init(lock, 0)==0) return lock;
 	else return 0;
 }
 
 #define lock_get(lock) pthread_mutex_lock(lock)
 #define lock_release(lock) pthread_mutex_unlock(lock)
 
 
 
 #elif defined USE_POSIX_SEM
 #include <semaphore.h>
 
 typedef sem_t gen_lock_t;
 
 #define lock_destroy(lock) /* do nothing */ 
 
 inline static gen_lock_t* lock_init(gen_lock_t* lock)
 {
 	if (sem_init(lock, 1, 1)<0) return 0;
 	return lock;
 }
 
 #define lock_get(lock) sem_wait(lock)
 #define lock_release(lock) sem_post(lock)
 
 
 #elif defined USE_SYSV_SEM
 #include <sys/ipc.h>
 #include <sys/sem.h>
 
 #if ((defined(HAVE_UNION_SEMUN) || defined(__GNU_LIBRARY__) )&& !defined(_SEM_SEMUN_UNDEFINED)) 
 	
 	/* union semun is defined by including sem.h */
 #else
 	/* according to X/OPEN we have to define it ourselves */
 	union semun {
 		int val;                      /* value for SETVAL */
 		struct semid_ds *buf;         /* buffer for IPC_STAT, IPC_SET */
 		unsigned short int *array;    /* array for GETALL, SETALL */
 		struct seminfo *__buf;        /* buffer for IPC_INFO */
 	};
 #endif
 
 typedef int gen_lock_t;
 
 
 
 
 inline static gen_lock_t* lock_init(gen_lock_t* lock)
 {
 	union semun su;
 	
 	*lock=semget(IPC_PRIVATE, 1, 0700);
 	if (*lock==-1) return 0;
 	su.val=1;
 	if (semctl(*lock, 0, SETVAL, su)==-1){
 		/* init error*/
 		return 0;
 	}
 	return lock;
 }
 
 inline static void lock_destroy(gen_lock_t* lock)
 {
 	semctl(*lock, 0, IPC_RMID, (union semun)(int)0);
 }
 
 
 inline static void lock_get(gen_lock_t* lock)
 {
 	struct sembuf sop;
 
 	sop.sem_num=0;
 	sop.sem_op=-1; /* down */
 	sop.sem_flg=0; 
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 tryagain:
 	if (semop(*lock, &sop, 1)==-1){
 		if (errno==EINTR){
 			DBG("lock_get: signal received while waiting for on a mutex\n");
 			goto tryagain;
 		}else{
 			LOG(L_CRIT, "ERROR: lock_get sysv: %s (%d)\n", strerror(errno),
 						errno);
 		}
 	}
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 }
 
 inline static void lock_release(gen_lock_t* lock)
 {
 	struct sembuf sop;
 	
 	sop.sem_num=0;
 	sop.sem_op=1; /* up */
 	sop.sem_flg=0; 
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 tryagain:
 	if (semop(*lock, &sop, 1)==-1){
 		if (errno==EINTR){
 			/* very improbable*/
 			DBG("lock_release: signal received while releasing a mutex\n");
 			goto tryagain;
 		}else{
 			LOG(L_CRIT, "ERROR: lock_release sysv: %s (%d)\n",
 					strerror(errno), errno);
 		}
 	}
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 }
 
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 #else
 #error "no locking method selected"
 #endif
 
 
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 /* lock sets */
 
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 #if defined(FAST_LOCK) || defined(USE_PTHREAD_MUTEX) || defined(USE_POSIX_SEM)
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 #define GEN_LOCK_T_PREFERED
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 struct lock_set_t_ {
 	long size;
 	gen_lock_t* locks;
 }; /* must be  aligned (32 bits or 64 depending on the arch)*/
 typedef struct lock_set_t_ lock_set_t;
 
 
 #define lock_set_destroy(lock_set) /* do nothing */
 
 inline static lock_set_t* lock_set_init(lock_set_t* s)
 {
 	int r;
 	for (r=0; r<s->size; r++) if (lock_init(&s->locks[r])==0) return 0;
 	return s;
 }
 
 /* WARNING: no boundary checks!*/
 #define lock_set_get(set, i) lock_get(&set->locks[i])
 #define lock_set_release(set, i) lock_release(&set->locks[i])
 
 #elif defined(USE_SYSV_SEM)
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 #undef GEN_LOCK_T_PREFERED
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 struct lock_set_t_ {
 	int size;
 	int semid;
 };
 
 
 typedef struct lock_set_t_ lock_set_t;
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 inline static lock_set_t* lock_set_init(lock_set_t* s)
 {
 	union semun su;
 	int r;
 	
 	s->semid=semget(IPC_PRIVATE, s->size, 0700);
 	if (s->semid==-1){
 		LOG(L_CRIT, "ERROR: lock_set_init (SYSV): semget failed: %s\n",
 				strerror(errno));
 		return 0;
 	}
 	su.val=1;
 	for (r=0; r<s->size; r++){
 		if (semctl(s->semid, r, SETVAL, su)==-1){
 			LOG(L_CRIT, "ERROR: lock_set_init (SYSV): semctl failed on sem %d"
 					": %s\n", r, strerror(errno));
 			semctl(s->semid, 0, IPC_RMID, (union semun)(int)0);
 			return 0;
 		}
 	}
 	return s;
 }
 
 inline static void lock_set_destroy(lock_set_t* s)
 {
 	semctl(s->semid, 0, IPC_RMID, (union semun)(int)0);
 }
 
 inline static void lock_set_get(lock_set_t* s, int n)
 {
 	struct sembuf sop;
 	sop.sem_num=n;
 	sop.sem_op=-1; /* down */
 	sop.sem_flg=0;
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 tryagain:
 	if (semop(s->semid, &sop, 1)==-1){
 		if (errno==EINTR){
 			DBG("lock_set_get: signal received while waiting on a mutex\n");
 			goto tryagain;
 		}else{
 			LOG(L_CRIT, "ERROR: lock_set_get sysv: %s (%d)\n",
 					strerror(errno), errno);
 		}
 	}
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 }
 
 inline static void lock_set_release(lock_set_t* s, int n)
 {
 	struct sembuf sop;
 	sop.sem_num=n;
 	sop.sem_op=1; /* up */
 	sop.sem_flg=0;
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 tryagain:
 	if (semop(s->semid, &sop, 1)==-1){
 		if (errno==EINTR){
 			/* very improbable */
 			DBG("lock_set_release: signal received while releasing mutex\n");
 			goto tryagain;
 		}else{
 			LOG(L_CRIT, "ERROR: lock_set_release sysv: %s (%d)\n",
 					strerror(errno), errno);
 		}
 	}
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 }
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 #else 
 #error "no lock set method selected"
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 #endif
 
 
 #endif