shm_mem.c

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/* $Id: shm_mem.c 5035 2008-10-06 11:01:24Z henningw $
 *
 * Shared memory functions
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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
 *
 * History:
 * --------
 *  2003-03-12  split shm_mem_init in shm_getmem & shm_mem_init_mallocs
 *               (andrei)
 *  2004-07-27  ANON mmap support, needed on darwin (andrei)
 *  2004-09-19  shm_mem_destroy: destroy first the lock & then unmap (andrei)
 */


#include <stdlib.h>

#include "shm_mem.h"
#include "../config.h"
#include "../globals.h"

#ifdef  SHM_MMAP

#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h> /*open*/
#include <sys/stat.h>
#include <fcntl.h>

#endif


#ifdef STATISTICS
stat_export_t shm_stats[] = {
   {"total_size" ,     STAT_IS_FUNC,    (stat_var**)shm_get_size     },
   {"used_size" ,      STAT_IS_FUNC,    (stat_var**)shm_get_used     },
   {"real_used_size" , STAT_IS_FUNC,    (stat_var**)shm_get_rused    },
   {"max_used_size" ,  STAT_IS_FUNC,    (stat_var**)shm_get_mused    },
   {"free_size" ,      STAT_IS_FUNC,    (stat_var**)shm_get_free     },
   {"fragments" ,      STAT_IS_FUNC,    (stat_var**)shm_get_frags    },
   {0,0,0}
};
#endif



#ifndef SHM_MMAP
static int shm_shmid=-1; /*shared memory id*/
#endif

gen_lock_t* mem_lock=0;

static void* shm_mempool=(void*)-1;
#ifdef F_MALLOC
   struct fm_block* shm_block;
#else
   struct qm_block* shm_block;
#endif


inline static void* sh_realloc(void* p, unsigned int size)
{
   void *r;
   shm_lock(); 
   shm_free_unsafe(p);
   r=shm_malloc_unsafe(size);
   shm_unlock();
   return r;
}

/* look at a buffer if there is perhaps enough space for the new size
   (It is beneficial to do so because vq_malloc is pretty stateful
    and if we ask for a new buffer size, we can still make it happy
    with current buffer); if so, we return current buffer again;
    otherwise, we free it, allocate a new one and return it; no
    guarantee for buffer content; if allocation fails, we return
    NULL
*/

#ifdef DBG_QM_MALLOC
void* _shm_resize( void* p, unsigned int s, const char* file, const char* func,
                     int line)
#else
void* _shm_resize( void* p , unsigned int s)
#endif
{
   if (p==0) {
      LM_DBG("resize(0) called\n");
      return shm_malloc( s );
   }
   return sh_realloc( p, s ); 
}





int shm_getmem(void)
{

#ifdef SHM_MMAP
   int fd;
#else
   struct shmid_ds shm_info;
#endif

#ifdef SHM_MMAP
   if (shm_mempool && (shm_mempool!=(void*)-1)){
#else
   if ((shm_shmid!=-1)||(shm_mempool!=(void*)-1)){
#endif
      LM_CRIT("shm already initialized\n");
      return -1;
   }
   
#ifdef SHM_MMAP
#ifdef USE_ANON_MMAP
   shm_mempool=mmap(0, shm_mem_size, PROT_READ|PROT_WRITE,
                MAP_ANON|MAP_SHARED, -1 ,0);
#else
   fd=open("/dev/zero", O_RDWR);
   if (fd==-1){
      LM_CRIT("could not open /dev/zero: %s\n", strerror(errno));
      return -1;
   }
   shm_mempool=mmap(0, shm_mem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd ,0);
   /* close /dev/zero */
   close(fd);
#endif /* USE_ANON_MMAP */
#else
   
   shm_shmid=shmget(IPC_PRIVATE, /* SHM_MEM_SIZE */ shm_mem_size , 0700);
   if (shm_shmid==-1){
      LM_CRIT("could not allocate shared memory segment: %s\n",
            strerror(errno));
      return -1;
   }
   shm_mempool=shmat(shm_shmid, 0, 0);
#endif
   if (shm_mempool==(void*)-1){
      LM_CRIT("could not attach shared memory segment: %s\n",
            strerror(errno));
      /* destroy segment*/
      shm_mem_destroy();
      return -1;
   }
   return 0;
}



int shm_mem_init_mallocs(void* mempool, unsigned long pool_size)
{
   /* init it for malloc*/
   shm_block=shm_malloc_init(mempool, pool_size);
   if (shm_block==0){
      LM_CRIT("could not initialize shared malloc\n");
      shm_mem_destroy();
      return -1;
   }
   mem_lock=shm_malloc_unsafe(sizeof(gen_lock_t)); /* skip lock_alloc, 
                                          race cond*/
   if (mem_lock==0){
      LM_CRIT("could not allocate lock\n");
      shm_mem_destroy();
      return -1;
   }
   if (lock_init(mem_lock)==0){
      LM_CRIT("could not initialize lock\n");
      shm_mem_destroy();
      return -1;
   }
   
   LM_DBG("success\n");
   
   return 0;
}


int shm_mem_init(void)
{
   int ret;
   
   ret=shm_getmem();
   if (ret<0) return ret;
   return shm_mem_init_mallocs(shm_mempool, shm_mem_size);
}


void shm_mem_destroy(void)
{
#ifndef SHM_MMAP
   struct shmid_ds shm_info;
#endif
   
   LM_DBG("\n");
   if (mem_lock){
      LM_DBG("destroying the shared memory lock\n");
      lock_destroy(mem_lock); /* we don't need to dealloc it*/
   }
   if (shm_mempool && (shm_mempool!=(void*)-1)) {
#ifdef SHM_MMAP
      munmap(shm_mempool, /* SHM_MEM_SIZE */ shm_mem_size );
#else
      shmdt(shm_mempool);
#endif
      shm_mempool=(void*)-1;
   }
#ifndef SHM_MMAP
   if (shm_shmid!=-1) {
      shmctl(shm_shmid, IPC_RMID, &shm_info);
      shm_shmid=-1;
   }
#endif
}