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 #if defined(USE_STREAM_CACHE) && !defined(WIN32)
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <sys/types.h>
  19 #include <sys/time.h>
  20 #include <sys/uio.h>
  21 #ifdef HAVE_SYS_MMAN_H
  22 #include <sys/mman.h>
  23 #elif defined(__BEOS__)
  24 #include <mman.h>
  25 #endif
  26 #include <sys/socket.h>
  27 #include <fcntl.h>
  28
  29 #include "mp_msg.h"
  30
  31 #ifdef AIX
  32 #include <sys/select.h>
  33 #endif
  34
  35 #ifdef HAVE_SHM
  36 #include <sys/ipc.h>
  37 #include <sys/shm.h>
  38 #endif
  39
  40 #if defined(MAP_ANONYMOUS) && !defined(MAP_ANON)
  41 #define MAP_ANON MAP_ANONYMOUS
  42 #endif
  43
  44 static int shmem_type=0;
  45
  46 void* shmem_alloc(int size){
  47 void* p;
  48 static int devzero = -1;
  49 while(1){
  50   switch(shmem_type){
  51   case 0:  // ========= MAP_ANON|MAP_SHARED ==========
  52 #ifdef MAP_ANON
  53     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
  54     if(p==MAP_FAILED) break; // failed
  55     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap anon (%p)\n",size,p);
  56     return p;
  57 #else
  58 // system does not support MAP_ANON at all (e.g. solaris 2.5.1/2.6), just fail
  59     mp_dbg(MSGT_OSDEP, MSGL_DBG3, "shmem: using mmap anon failed\n");
  60 #endif
  61     break;
  62   case 1:  // ========= MAP_SHARED + /dev/zero ==========
  63     if (devzero == -1 && (devzero = open("/dev/zero", O_RDWR, 0)) == -1) break;
  64     p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,devzero,0);
  65     if(p==MAP_FAILED) break; // failed
  66     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap /dev/zero (%p)\n",size,p);
  67     return p;
  68   case 2: { // ========= shmget() ==========
  69 #ifdef HAVE_SHM
  70     struct shmid_ds shmemds;
  71     int shmemid;
  72     if ((shmemid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600)) == -1) break;
  73     if ((p = shmat(shmemid, 0, 0)) == (void *)-1){
  74       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmat() failed: %s\n", strerror(errno));
  75       shmctl (shmemid, IPC_RMID, &shmemds);
  76       break;
  77     }
  78     if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) {
  79       mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmctl() failed: %s\n", strerror(errno));
  80       if (shmdt(p) == -1) perror ("shmdt()");
  81       break;
  82     }
  83     mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using SHM (%p)\n",size,p);
  84     return p;
  85 #else
  86     mp_msg(MSGT_OSDEP, MSGL_FATAL, "shmem: no SHM support was compiled in!\n");
  87     return(NULL);
  88 #endif
  89     }
  90   default:
  91     mp_msg(MSGT_OSDEP, MSGL_FATAL,
  92         "FATAL: Cannot allocate %d bytes of shared memory :(\n",size);
  93     return NULL;
  94   }
  95   ++shmem_type;
  96 }
  97 }
  98
  99 void shmem_free(void* p,int size){
 100   switch(shmem_type){
 101     case 0:
 102     case 1:
 103             if(munmap(p,size)) {
 104                 mp_msg(MSGT_OSDEP, MSGL_ERR, "munmap failed on %p %d bytes: %s\n",
 105                     p,size,strerror(errno));
 106             }
 107       break;
 108     case 2:
 109 #ifdef HAVE_SHM
 110             if (shmdt(p) == -1)
 111                 mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: shmdt() failed: %s\n",
 112                     strerror(errno));
 113 #else
 114             mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: no SHM support was compiled in!\n");
 115 #endif
 116       break;
 117   }
 118 }
 119
 120 #endif