#include "shm.h"
#include "util.h"
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/mman.h>
#include <sys/shm.h>
#ifdef __ANDROID__
#include <linux/ashmem.h>
#include <sys/ioctl.h>
#endif
#ifdef __ANDROID__
#define ASHMEM_DEVICE "/dev/ashmem"
void *shm_create(size_t size) {
int fd = -1;
char ourkey[11] = {0};
void *addr = MAP_FAILED;
struct ashmem_pin pin = {0, size};
fd = open(ASHMEM_DEVICE, O_RDWR);
if (fd < 0) { FFATAL("Failed open /dev/ashmem: %d", errno); }
if (snprintf(ourkey, sizeof(ourkey) - 1, "%d", IPC_PRIVATE) < 0) {
FFATAL("Failed to generate key: %d", errno);
}
if (ioctl(fd, ASHMEM_SET_NAME, ourkey) < 0) {
FFATAL("ioctl(ASHMEM_SET_NAME) errno: %d\n", errno);
}
if (ioctl(fd, ASHMEM_SET_SIZE, size) < 0) {
FFATAL("ioctl(ASHMEM_SET_SIZE) errno: %d\n", errno);
}
addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (addr == MAP_FAILED) { FFATAL("mmap failed: %d\n", errno); }
/* Shared memory pinning has been deprecated. So if the ioctl fails, then
just assume we are running on a version where it has been. Worst case, we
will leak the shared memory region.*/
ioctl(fd, ASHMEM_UNPIN, &pin);
close(fd);
return addr;
}
#else
void *shm_create(size_t size) {
int shm_id =
shmget(IPC_PRIVATE, size, IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR);
if (shm_id < 0) { FFATAL("shm_id < 0 - errno: %d\n", errno); }
void *addr = shmat(shm_id, NULL, 0);
if (addr == MAP_FAILED) { FFATAL("addr == MAP_FAILED - errno: %d\n", errno); }
/*
* Configure the shared memory region to be removed once the process
* dies.
*/
if (shmctl(shm_id, IPC_RMID, NULL) < 0) {
FFATAL("shmctl (IPC_RMID) < 0 - errno: %d\n", errno);
}
/* Clear it, not sure it's necessary, just seems like good practice */
memset(addr, '\0', size);
return addr;
}
#endif
