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The Android Open Source Projectdd7bc332009-03-03 19:32:55 -08001/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*
18 * Implementation of the user-space ashmem API for the simulator, which lacks
19 * an ashmem-enabled kernel. See ashmem-dev.c for the real ashmem-based version.
20 */
21
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080022#include <errno.h>
Mark Salyzyn12717162014-04-29 15:49:14 -070023#include <fcntl.h>
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080024#include <limits.h>
Mathieu Chartier1104ae82014-06-03 10:24:21 -070025#include <stdbool.h>
Mark Salyzyn12717162014-04-29 15:49:14 -070026#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <sys/stat.h>
30#include <sys/types.h>
31#include <time.h>
32#include <unistd.h>
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080033
34#include <cutils/ashmem.h>
Elliott Hughes2004a862015-02-09 11:41:07 -080035#include <utils/Compat.h>
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080036
Mark Salyzynedc70932014-05-02 12:23:56 -070037#ifndef __unused
Mark Salyzyn12717162014-04-29 15:49:14 -070038#define __unused __attribute__((__unused__))
Mark Salyzynedc70932014-05-02 12:23:56 -070039#endif
Mark Salyzyn12717162014-04-29 15:49:14 -070040
41int ashmem_create_region(const char *ignored __unused, size_t size)
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080042{
Elliott Hughes2004a862015-02-09 11:41:07 -080043 char template[PATH_MAX];
44 snprintf(template, sizeof(template), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid());
45 int fd = mkstemp(template);
Elliott Hughes39180902015-12-16 08:33:52 -080046 if (fd == -1) return -1;
47
48 unlink(template);
49
50 if (TEMP_FAILURE_RETRY(ftruncate(fd, size)) == -1) {
51 close(fd);
52 return -1;
Mathieu Chartier1104ae82014-06-03 10:24:21 -070053 }
Elliott Hughes39180902015-12-16 08:33:52 -080054
55 return fd;
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080056}
57
Mark Salyzyn12717162014-04-29 15:49:14 -070058int ashmem_set_prot_region(int fd __unused, int prot __unused)
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080059{
Mathieu Chartier1104ae82014-06-03 10:24:21 -070060 return 0;
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080061}
62
Mark Salyzyn12717162014-04-29 15:49:14 -070063int ashmem_pin_region(int fd __unused, size_t offset __unused, size_t len __unused)
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080064{
Elliott Hughes427c6052016-05-13 14:47:30 -070065 return 0 /*ASHMEM_NOT_PURGED*/;
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080066}
67
Mark Salyzyn12717162014-04-29 15:49:14 -070068int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __unused)
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080069{
Elliott Hughes427c6052016-05-13 14:47:30 -070070 return 0 /*ASHMEM_IS_UNPINNED*/;
The Android Open Source Projectdd7bc332009-03-03 19:32:55 -080071}
Bjorn Bringert7be52b12009-06-02 00:41:09 +010072
73int ashmem_get_size_region(int fd)
74{
Mathieu Chartier1104ae82014-06-03 10:24:21 -070075 struct stat buf;
Elliott Hughes2004a862015-02-09 11:41:07 -080076 int result = fstat(fd, &buf);
Mathieu Chartier1104ae82014-06-03 10:24:21 -070077 if (result == -1) {
78 return -1;
79 }
Bjorn Bringert7be52b12009-06-02 00:41:09 +010080
Mark Salyzync2d8aad2016-02-02 08:05:54 -080081 /*
82 * Check if this is an "ashmem" region.
83 * TODO: This is very hacky, and can easily break.
84 * We need some reliable indicator.
85 */
Mathieu Chartier1104ae82014-06-03 10:24:21 -070086 if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) {
87 errno = ENOTTY;
88 return -1;
89 }
Bjorn Bringert7be52b12009-06-02 00:41:09 +010090
Elliott Hughes2004a862015-02-09 11:41:07 -080091 return buf.st_size;
Bjorn Bringert7be52b12009-06-02 00:41:09 +010092}