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/*
* shmem.c - Shared memory allocation
*
* based on mpg123's xfermem.c by
* Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de>
* Sun Apr 6 02:26:26 MET DST 1997
*/
#include "../config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/uio.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <sys/socket.h>
#include <fcntl.h>
#include "../mp_msg.h"
#ifdef AIX
#include <sys/select.h>
#endif
#ifdef HAVE_SHM
#include <sys/ipc.h>
#include <sys/shm.h>
#endif
#if defined(MAP_ANONYMOUS) && !defined(MAP_ANON)
#define MAP_ANON MAP_ANONYMOUS
#endif
static int shmem_type=0;
void* shmem_alloc(int size){
void* p;
static int devzero = -1;
while(1){
switch(shmem_type){
case 0: // ========= MAP_ANON|MAP_SHARED ==========
#ifdef MAP_ANON
p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
if(p==MAP_FAILED) break; // failed
mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap anon (%p)\n",size,p);
return p;
#else
// system does not support MAP_ANON at all (e.g. solaris 2.5.1/2.6), just fail
mp_dbg(MSGT_OSDEP, MSGL_DBG3, "shmem: using mmap anon failed\n");
#endif
break;
case 1: // ========= MAP_SHARED + /dev/zero ==========
if (devzero == -1 && (devzero = open("/dev/zero", O_RDWR, 0)) == -1) break;
p=mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,devzero,0);
if(p==MAP_FAILED) break; // failed
mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using mmap /dev/zero (%p)\n",size,p);
return p;
case 2: { // ========= shmget() ==========
#ifdef HAVE_SHM
struct shmid_ds shmemds;
int shmemid;
if ((shmemid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600)) == -1) break;
if ((int)(p = shmat(shmemid, 0, 0)) == -1){
mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmat() failed: %s\n", strerror(errno));
shmctl (shmemid, IPC_RMID, &shmemds);
break;
}
if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) {
mp_msg(MSGT_OSDEP, MSGL_ERR, "shmem: shmctl() failed: %s\n", strerror(errno));
if (shmdt(p) == -1) perror ("shmdt()");
break;
}
mp_dbg(MSGT_OSDEP, MSGL_DBG2, "shmem: %d bytes allocated using SHM (%p)\n",size,p);
return p;
#else
mp_msg(MSGT_OSDEP, MSGL_FATAL, "shmem: no SHM support was compiled in!\n");
return(NULL);
#endif
}
default:
mp_msg(MSGT_OSDEP, MSGL_FATAL,
"FATAL: Cannot allocate %d bytes of shared memory :(\n",size);
return NULL;
}
++shmem_type;
}
}
void shmem_free(void* p){
switch(shmem_type){
case 2:
#ifdef HAVE_SHM
if (shmdt(p) == -1)
mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: shmdt() failed: %s\n",
strerror(errno));
#else
mp_msg(MSGT_OSDEP, MSGL_ERR, "shmfree: no SHM support was compiled in!\n");
#endif
break;
}
}
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