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
  44 #ifdef AIX
  45 #include <sys/select.h>
  46 #endif
  47
  48 #ifdef HAVE_SHM
  49 #include <sys/ipc.h>
  50 #include <sys/shm.h>
  51 #endif
  52
  53 #if defined(MAP_ANONYMOUS) && !defined(MAP_ANON)
  54 #define MAP_ANON MAP_ANONYMOUS
  55 #endif
  56
  57 static int shmem_type=0;
  58
  59 void* shmem_alloc(int size){
  60 void* p;
  61 static int devzero = -1;
  62 while(1){
  63   switch(shmem_type){
  64   case 0:  // ========= MAP_ANON|MAP_SHARED ==========
  65 #ifdef MAP_ANON
  66     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
  67     if(p==MAP_FAILED) break; // failed
  68     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap anon (%p)\n",size,p);
  69     return p;
  70 #else
  71 // system does not support MAP_ANON at all (e.g. solaris 2.5.1/2.6), just fail
  72     mp_dbg(MSGT_OSDEP, MSGL_DBG3, "shmem: using mmap anon failed\n");
  73 #endif
  74     break;
  75   case 1:  // ========= MAP_SHARED + /dev/zero ==========
  76     if (devzero == -1 && (devzero = open("/dev/zero", O_RDWR, 0)) == -1) break;
  77     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,devzero,0);
  78     if(p==MAP_FAILED) break; // failed
  79     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap /dev/zero (%p)\n",size,p);
  80     return p;
  81   case 2: { // ========= shmget() ==========
  82 #ifdef HAVE_SHM
  83     struct shmid_ds shmemds;
  84     int shmemid;
  85     if ((shmemid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600)) == -1) break;
  86     if ((p = shmat(shmemid, 0, 0)) == (void *)-1){
  87       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmat() failed: %s\n", strerror(errno));
  88       shmctl (shmemid, IPC_RMID, &shmemds);
  89       break;
  90     }
  91     if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) {
  92       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmctl() failed: %s\n", strerror(errno));
  93       if (shmdt(p) == -1) perror ("shmdt()");
  94       break;
  95     }
  96     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using SHM (%p)\n",size,p);
  97     return p;
  98 #else
  99     mp_msg(MSGT_OSDEP, MSGL_FATAL, "shmem: no SHM support was compiled in!\n");
 100     return NULL;
 101 #endif
 102     }
 103   default:
 104     mp_msg(MSGT_OSDEP, MSGL_FATAL,
 105         "FATAL: Cannot allocate %d bytes of shared memory :(\n",size);
 106     return NULL;
 107   }
 108   ++shmem_type;
 109 }
 110 }
 111
 112 void shmem_free(void* p,int size){
 113   switch(shmem_type){
 114     case 0:
 115     case 1:
 116             if(munmap(p,size)) {
 117                 mp_msg(MSGT_OSDEP, MSGL_ERR, "munmap failed on %p %d bytes: %s\n",
 118                     p,size,strerror(errno));
 119             }
 120       break;
 121     case 2:
 122 #ifdef HAVE_SHM
 123             if (shmdt(p) == -1)
 124                 mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: shmdt() failed: %s\n",
 125                     strerror(errno));
 126 #else
 127             mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: no SHM support was compiled in!\n");
 128 #endif
 129       break;
 130   }
 131 }