osdep/shmem.c

   1 /*
   2  * shared memory allocation
   3  *
   4  * based on mpg123's xfermem.c by
   5  * Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de>
   6  *
   7  * This file is part of MPlayer.
   8  *
   9  * MPlayer is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * MPlayer is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #include "config.h"
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <errno.h>
  31 #include <sys/types.h>
  32 #include <sys/time.h>
  33 #include <sys/uio.h>
  34 #ifdef HAVE_SYS_MMAN_H
  35 #include <sys/mman.h>
  36 #elif defined(__BEOS__)
  37 #include <mman.h>
  38 #endif
  39 #include <sys/socket.h>
  40 #include <fcntl.h>
  41
  42 #include "mp_msg.h"
  43 #include "shmem.h"
  44
  45 #ifdef AIX
  46 #include <sys/select.h>
  47 #endif
  48
  49 #ifdef HAVE_SHM
  50 #include <sys/ipc.h>
  51 #include <sys/shm.h>
  52 #endif
  53
  54 #if defined(MAP_ANONYMOUS) && !defined(MAP_ANON)
  55 #define MAP_ANON MAP_ANONYMOUS
  56 #endif
  57
  58 static int shmem_type=0;
  59
  60 void* shmem_alloc(int size){
  61 void* p;
  62 static int devzero = -1;
  63 while(1){
  64   switch(shmem_type){
  65   case 0:  // ========= MAP_ANON|MAP_SHARED ==========
  66 #ifdef MAP_ANON
  67     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
  68     if(p==MAP_FAILED) break; // failed
  69     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap anon (%p)\n",size,p);
  70     return p;
  71 #else
  72 // system does not support MAP_ANON at all (e.g. solaris 2.5.1/2.6), just fail
  73     mp_dbg(MSGT_OSDEP, MSGL_DBG3, "shmem: using mmap anon failed\n");
  74 #endif
  75     break;
  76   case 1:  // ========= MAP_SHARED + /dev/zero ==========
  77     if (devzero == -1 && (devzero = open("/dev/zero", O_RDWR, 0)) == -1) break;
  78     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,devzero,0);
  79     if(p==MAP_FAILED) break; // failed
  80     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap /dev/zero (%p)\n",size,p);
  81     return p;
  82   case 2: { // ========= shmget() ==========
  83 #ifdef HAVE_SHM
  84     struct shmid_ds shmemds;
  85     int shmemid;
  86     if ((shmemid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600)) == -1) break;
  87     if ((p = shmat(shmemid, 0, 0)) == (void *)-1){
  88       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmat() failed: %s\n", strerror(errno));
  89       shmctl (shmemid, IPC_RMID, &shmemds);
  90       break;
  91     }
  92     if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) {
  93       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmctl() failed: %s\n", strerror(errno));
  94       if (shmdt(p) == -1) perror ("shmdt()");
  95       break;
  96     }
  97     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using SHM (%p)\n",size,p);
  98     return p;
  99 #else
 100     mp_msg(MSGT_OSDEP, MSGL_FATAL, "shmem: no SHM support was compiled in!\n");
 101     return NULL;
 102 #endif
 103     }
 104   default:
 105     mp_msg(MSGT_OSDEP, MSGL_FATAL,
 106         "FATAL: Cannot allocate %d bytes of shared memory :(\n",size);
 107     return NULL;
 108   }
 109   ++shmem_type;
 110 }
 111 }
 112
 113 void shmem_free(void* p,int size){
 114   switch(shmem_type){
 115     case 0:
 116     case 1:
 117             if(munmap(p,size)) {
 118                 mp_msg(MSGT_OSDEP, MSGL_ERR, "munmap failed on %p %d bytes: %s\n",
 119                     p,size,strerror(errno));
 120             }
 121       break;
 122     case 2:
 123 #ifdef HAVE_SHM
 124             if (shmdt(p) == -1)
 125                 mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: shmdt() failed: %s\n",
 126                     strerror(errno));
 127 #else
 128             mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: no SHM support was compiled in!\n");
 129 #endif
 130       break;
 131   }
 132 }