115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
|
/*
|
||
|
|
* Copyright (C) 2008 The Android Open Source Project
|
||
|
|
*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Implementation of the user-space ashmem API for the simulator, which lacks
|
||
|
|
* an ashmem-enabled kernel. See ashmem-dev.c for the real ashmem-based version.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <sys/stat.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <time.h>
|
||
|
|
#include <limits.h>
|
||
|
|
|
||
|
|
#include <cutils/ashmem.h>
|
||
|
|
|
||
|
|
int ashmem_create_region(const char *ignored, size_t size)
|
||
|
|
{
|
||
|
|
static const char txt[] = "abcdefghijklmnopqrstuvwxyz"
|
||
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
|
||
|
|
char name[64];
|
||
|
|
unsigned int retries = 0;
|
||
|
|
pid_t pid = getpid();
|
||
|
|
int fd;
|
||
|
|
|
||
|
|
srand(time(NULL) + pid);
|
||
|
|
|
||
|
|
retry:
|
||
|
|
/* not beautiful, its just wolf-like loop unrolling */
|
||
|
|
snprintf(name, sizeof(name), "/tmp/android-ashmem-%d-%c%c%c%c%c%c%c%c",
|
||
|
|
pid,
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
|
||
|
|
txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))]);
|
||
|
|
|
||
|
|
/* open O_EXCL & O_CREAT: we are either the sole owner or we fail */
|
||
|
|
fd = open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
|
||
|
|
if (fd == -1) {
|
||
|
|
/* unlikely, but if we failed because `name' exists, retry */
|
||
|
|
if (errno == EEXIST && ++retries < 6)
|
||
|
|
goto retry;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* truncate the file to `len' bytes */
|
||
|
|
if (ftruncate(fd, size) == -1)
|
||
|
|
goto error;
|
||
|
|
|
||
|
|
if (unlink(name) == -1)
|
||
|
|
goto error;
|
||
|
|
|
||
|
|
return fd;
|
||
|
|
error:
|
||
|
|
close(fd);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ashmem_set_prot_region(int fd, int prot)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ashmem_pin_region(int fd, size_t offset, size_t len)
|
||
|
|
{
|
||
|
|
return ASHMEM_NOT_PURGED;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ashmem_unpin_region(int fd, size_t offset, size_t len)
|
||
|
|
{
|
||
|
|
return ASHMEM_IS_UNPINNED;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ashmem_get_size_region(int fd)
|
||
|
|
{
|
||
|
|
struct stat buf;
|
||
|
|
int result;
|
||
|
|
|
||
|
|
result = fstat(fd, &buf);
|
||
|
|
if (result == -1) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check if this is an "ashmem" region.
|
||
|
|
// TODO: This is very hacky, and can easily break. We need some reliable indicator.
|
||
|
|
if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) {
|
||
|
|
errno = ENOTTY;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return (int)buf.st_size; // TODO: care about overflow (> 2GB file)?
|
||
|
|
}
|