os/os-android.h: fix alignment problems in shared memory functions

[fio.git] / os / os-android.h

diff --git a/os/os-android.h b/os/os-android.h
index 1d11cccde42bdd8b1db35bf016ccb65d8f38ac62..f371116f8f6a9a45a37372b3044f71c77f88f368 100644 (file)
--- a/os/os-android.h
+++ b/os/os-android.h
@@ -57,18 +57,17 @@
 #define MAP_HUGETLB 0x40000 /* arch specific */
 #endif
 
-
+#ifndef CONFIG_NO_SHM
 /*
  * The Android NDK doesn't currently export <sys/shm.h>, so define the
  * necessary stuff here.
  */
 
-#include <linux/shm.h>
+#include <sys/shm.h>
 #define SHM_HUGETLB    04000
 
 #include <stdio.h>
 #include <linux/ashmem.h>
-#include <sys/mman.h>
 
 #define ASHMEM_DEVICE  "/dev/ashmem"
 
@@ -88,23 +87,24 @@ static inline int shmctl (int __shmid, int __cmd, struct shmid_ds *__buf)
 static inline int shmget (key_t __key, size_t __size, int __shmflg)
 {
        int fd,ret;
-       char key[11];
-       
+       char keybuf[11];
+
        fd = open(ASHMEM_DEVICE, O_RDWR);
        if (fd < 0)
                return fd;
 
-       sprintf(key,"%d",__key);
-       ret = ioctl(fd, ASHMEM_SET_NAME, key);
+       sprintf(keybuf,"%d",__key);
+       ret = ioctl(fd, ASHMEM_SET_NAME, keybuf);
        if (ret < 0)
                goto error;
 
-       ret = ioctl(fd, ASHMEM_SET_SIZE, __size);
+       /* Stores size in first 8 bytes, allocate extra space */
+       ret = ioctl(fd, ASHMEM_SET_SIZE, __size + sizeof(uint64_t));
        if (ret < 0)
                goto error;
 
        return fd;
-       
+
 error:
        close(fd);
        return ret;
@@ -112,20 +112,22 @@ error:
 
 static inline void *shmat (int __shmid, const void *__shmaddr, int __shmflg)
 {
-       size_t *ptr, size = ioctl(__shmid, ASHMEM_GET_SIZE, NULL);
-       ptr = mmap(NULL, size + sizeof(size_t), PROT_READ | PROT_WRITE, MAP_SHARED, __shmid, 0);
-       *ptr = size;    //save size at beginning of buffer, for use with munmap
-       return &ptr[1];
+       size_t size = ioctl(__shmid, ASHMEM_GET_SIZE, NULL);
+       /* Needs to be 8-byte aligned to prevent SIGBUS on 32-bit ARM */
+       uint64_t *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, __shmid, 0);
+       /* Save size at beginning of buffer, for use with munmap */
+       *ptr = size;
+       return ptr + 1;
 }
 
 static inline int shmdt (const void *__shmaddr)
 {
-       size_t *ptr, size;
-       ptr = (size_t *)__shmaddr;
-       ptr--;
-       size = *ptr;    //find mmap size which we stored at the beginning of the buffer
-       return munmap((void *)ptr, size + sizeof(size_t));
+       /* Find mmap size which we stored at the beginning of the buffer */
+       uint64_t *ptr = (uint64_t *)__shmaddr - 1;
+       size_t size = *ptr;
+       return munmap(ptr, size);
 }
+#endif
 
 #define SPLICE_DEF_SIZE        (64*1024)