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/*
* 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.
*/
#include <cutils/ashmem.h>
/*
* 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. A
* disk-backed temp file is the best option that is consistently supported
* across all host platforms.
*/
#include <android-base/unique_fd.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <utils/Compat.h>
#include <memory>
using android::base::unique_fd;
static bool ashmem_validate_stat(int fd, struct stat* buf) {
int result = fstat(fd, buf);
if (result == -1) {
return false;
}
// Check if this is an ashmem region. Since there's no such thing on the host,
// we can't actually implement that. Check that it's at least a regular file.
if (!S_ISREG(buf->st_mode)) {
errno = ENOTTY;
return false;
}
// In Win32, unlike Unix, the temp file is not unlinked immediately after
// creation.
#if !defined(_WIN32)
if (buf->st_nlink != 0) {
errno = ENOTTY;
return false;
}
#endif
return true;
}
int ashmem_valid(int fd) {
struct stat buf;
return ashmem_validate_stat(fd, &buf);
}
int ashmem_create_region(const char* /*ignored*/, size_t size) {
// Files returned by tmpfile are automatically removed.
std::unique_ptr<FILE, decltype(&fclose)> tmp(tmpfile(), &fclose);
if (!tmp) {
return -1;
}
int fd = fileno(tmp.get());
if (fd == -1) {
return -1;
}
unique_fd dupfd = unique_fd(dup(fd));
if (dupfd == -1) {
return -1;
}
if (TEMP_FAILURE_RETRY(ftruncate(dupfd, size)) == -1) {
return -1;
}
return dupfd.release();
}
int ashmem_set_prot_region(int /*fd*/, int /*prot*/) {
return 0;
}
int ashmem_pin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
return 0 /*ASHMEM_NOT_PURGED*/;
}
int ashmem_unpin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
return 0 /*ASHMEM_IS_UNPINNED*/;
}
int ashmem_get_size_region(int fd)
{
struct stat buf;
if (!ashmem_validate_stat(fd, &buf)) {
return -1;
}
return buf.st_size;
}
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