1/*
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
22#include <errno.h>
23#include <fcntl.h>
24#include <limits.h>
25#include <stdbool.h>
26#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>
33
34#include <cutils/ashmem.h>
35#include <utils/Compat.h>
36
37#ifndef __unused
38#define __unused __attribute__((__unused__))
39#endif
40
41int ashmem_create_region(const char *ignored __unused, size_t size)
42{
43    char template[PATH_MAX];
44    snprintf(template, sizeof(template), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid());
45    int fd = mkstemp(template);
46    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;
53    }
54
55    return fd;
56}
57
58int ashmem_set_prot_region(int fd __unused, int prot __unused)
59{
60    return 0;
61}
62
63int ashmem_pin_region(int fd __unused, size_t offset __unused, size_t len __unused)
64{
65    return 0 /*ASHMEM_NOT_PURGED*/;
66}
67
68int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __unused)
69{
70    return 0 /*ASHMEM_IS_UNPINNED*/;
71}
72
73int ashmem_get_size_region(int fd)
74{
75    struct stat buf;
76    int result = fstat(fd, &buf);
77    if (result == -1) {
78        return -1;
79    }
80
81    /*
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     */
86    if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) {
87        errno = ENOTTY;
88        return -1;
89    }
90
91    return buf.st_size;
92}
93