osdep/shmem.c

   1 /*
   2  *   shmem.c - Shared memory allocation
   3  *
   4  *   based on mpg123's xfermem.c by
   5  *   Oliver Fromme  <oliver.fromme@heim3.tu-clausthal.de>
   6  *   Sun Apr  6 02:26:26 MET DST 1997
   7  */
   8
   9 #include "config.h"
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <errno.h>
  16 #include <sys/types.h>
  17 #include <sys/time.h>
  18 #include <sys/uio.h>
  19 #ifdef HAVE_SYS_MMAN_H
  20 #include <sys/mman.h>
  21 #elif defined(__BEOS__)
  22 #include <mman.h>
  23 #endif
  24 #include <sys/socket.h>
  25 #include <fcntl.h>
  26
  27 #include "mp_msg.h"
  28
  29 #ifdef AIX
  30 #include <sys/select.h>
  31 #endif
  32
  33 #ifdef HAVE_SHM
  34 #include <sys/ipc.h>
  35 #include <sys/shm.h>
  36 #endif
  37
  38 #if defined(MAP_ANONYMOUS) && !defined(MAP_ANON)
  39 #define MAP_ANON MAP_ANONYMOUS
  40 #endif
  41
  42 static int shmem_type=0;
  43
  44 void* shmem_alloc(int size){
  45 void* p;
  46 static int devzero = -1;
  47 while(1){
  48   switch(shmem_type){
  49   case 0:  // ========= MAP_ANON|MAP_SHARED ==========
  50 #ifdef MAP_ANON
  51     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
  52     if(p==MAP_FAILED) break; // failed
  53     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap anon (%p)\n",size,p);
  54     return p;
  55 #else
  56 // system does not support MAP_ANON at all (e.g. solaris 2.5.1/2.6), just fail
  57     mp_dbg(MSGT_OSDEP, MSGL_DBG3, "shmem: using mmap anon failed\n");
  58 #endif
  59     break;
  60   case 1:  // ========= MAP_SHARED + /dev/zero ==========
  61     if (devzero == -1 && (devzero = open("/dev/zero", O_RDWR, 0)) == -1) break;
  62     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,devzero,0);
  63     if(p==MAP_FAILED) break; // failed
  64     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap /dev/zero (%p)\n",size,p);
  65     return p;
  66   case 2: { // ========= shmget() ==========
  67 #ifdef HAVE_SHM
  68     struct shmid_ds shmemds;
  69     int shmemid;
  70     if ((shmemid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600)) == -1) break;
  71     if ((p = shmat(shmemid, 0, 0)) == (void *)-1){
  72       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmat() failed: %s\n", strerror(errno));
  73       shmctl (shmemid, IPC_RMID, &shmemds);
  74       break;
  75     }
  76     if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) {
  77       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmctl() failed: %s\n", strerror(errno));
  78       if (shmdt(p) == -1) perror ("shmdt()");
  79       break;
  80     }
  81     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using SHM (%p)\n",size,p);
  82     return p;
  83 #else
  84     mp_msg(MSGT_OSDEP, MSGL_FATAL, "shmem: no SHM support was compiled in!\n");
  85     return NULL;
  86 #endif
  87     }
  88   default:
  89     mp_msg(MSGT_OSDEP, MSGL_FATAL,
  90         "FATAL: Cannot allocate %d bytes of shared memory :(\n",size);
  91     return NULL;
  92   }
  93   ++shmem_type;
  94 }
  95 }
  96
  97 void shmem_free(void* p,int size){
  98   switch(shmem_type){
  99     case 0:
 100     case 1:
 101             if(munmap(p,size)) {
 102                 mp_msg(MSGT_OSDEP, MSGL_ERR, "munmap failed on %p %d bytes: %s\n",
 103                     p,size,strerror(errno));
 104             }
 105       break;
 106     case 2:
 107 #ifdef HAVE_SHM
 108             if (shmdt(p) == -1)
 109                 mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: shmdt() failed: %s\n",
 110                     strerror(errno));
 111 #else
 112             mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: no SHM support was compiled in!\n");
 113 #endif
 114       break;
 115   }
 116 }