7c4beee9f9
Migrate to tmpfile and fileno for temp file operations. These calls are supported on MinGW, and the temp files are automatically cleaned up. A Windows variant of ashmem-host is needed to support CursorWindows on host Windows. In Windows, it is not possible to unlink an open file, so the nlink check in ashmem_validate_stat must be made Unix-only. Test: SQLiteDatabaseTest in Google3 Test: libcutils_test_static on Windows Bug: 317884162 Change-Id: I7fc0f1f49406b01549b7f4d7e138cb3e4d79be72
111 lines
2.9 KiB
C++
111 lines
2.9 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <cutils/ashmem.h>
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/*
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* Implementation of the user-space ashmem API for the simulator, which lacks an
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* ashmem-enabled kernel. See ashmem-dev.c for the real ashmem-based version. A
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* disk-backed temp file is the best option that is consistently supported
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* across all host platforms.
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*/
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#include <android-base/unique_fd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <time.h>
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#include <unistd.h>
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#include <utils/Compat.h>
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#include <memory>
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using android::base::unique_fd;
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static bool ashmem_validate_stat(int fd, struct stat* buf) {
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int result = fstat(fd, buf);
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if (result == -1) {
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return false;
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}
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// Check if this is an ashmem region. Since there's no such thing on the host,
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// we can't actually implement that. Check that it's at least a regular file.
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if (!S_ISREG(buf->st_mode)) {
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errno = ENOTTY;
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return false;
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}
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// In Win32, unlike Unix, the temp file is not unlinked immediately after
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// creation.
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#if !defined(_WIN32)
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if (buf->st_nlink != 0) {
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errno = ENOTTY;
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return false;
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}
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#endif
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return true;
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}
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int ashmem_valid(int fd) {
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struct stat buf;
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return ashmem_validate_stat(fd, &buf);
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}
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int ashmem_create_region(const char* /*ignored*/, size_t size) {
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// Files returned by tmpfile are automatically removed.
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std::unique_ptr<FILE, decltype(&fclose)> tmp(tmpfile(), &fclose);
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if (!tmp) {
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return -1;
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}
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int fd = fileno(tmp.get());
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if (fd == -1) {
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return -1;
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}
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unique_fd dupfd = unique_fd(dup(fd));
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if (dupfd == -1) {
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return -1;
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}
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if (TEMP_FAILURE_RETRY(ftruncate(dupfd, size)) == -1) {
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return -1;
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}
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return dupfd.release();
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}
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int ashmem_set_prot_region(int /*fd*/, int /*prot*/) {
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return 0;
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}
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int ashmem_pin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
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return 0 /*ASHMEM_NOT_PURGED*/;
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}
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int ashmem_unpin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
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return 0 /*ASHMEM_IS_UNPINNED*/;
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}
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int ashmem_get_size_region(int fd)
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{
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struct stat buf;
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if (!ashmem_validate_stat(fd, &buf)) {
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return -1;
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}
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return buf.st_size;
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}
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