154 lines
4.2 KiB
C++
154 lines
4.2 KiB
C++
/*
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* Copyright (C) 2015 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 "android-base/file.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <string>
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#include "android-base/macros.h" // For TEMP_FAILURE_RETRY on Darwin.
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#include "android-base/utf8.h"
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#define LOG_TAG "base.file"
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#include "cutils/log.h"
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#include "utils/Compat.h"
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#if !defined(_WIN32)
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#define O_BINARY 0
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#endif
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namespace android {
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namespace base {
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// Versions of standard library APIs that support UTF-8 strings.
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using namespace android::base::utf8;
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bool ReadFdToString(int fd, std::string* content) {
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content->clear();
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char buf[BUFSIZ];
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ssize_t n;
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while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], sizeof(buf)))) > 0) {
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content->append(buf, n);
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}
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return (n == 0) ? true : false;
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}
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bool ReadFileToString(const std::string& path, std::string* content) {
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content->clear();
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int fd = TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC | O_NOFOLLOW | O_BINARY));
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if (fd == -1) {
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return false;
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}
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bool result = ReadFdToString(fd, content);
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close(fd);
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return result;
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}
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bool WriteStringToFd(const std::string& content, int fd) {
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const char* p = content.data();
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size_t left = content.size();
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while (left > 0) {
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ssize_t n = TEMP_FAILURE_RETRY(write(fd, p, left));
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if (n == -1) {
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return false;
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}
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p += n;
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left -= n;
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}
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return true;
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}
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static bool CleanUpAfterFailedWrite(const std::string& path) {
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// Something went wrong. Let's not leave a corrupt file lying around.
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int saved_errno = errno;
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unlink(path.c_str());
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errno = saved_errno;
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return false;
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}
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#if !defined(_WIN32)
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bool WriteStringToFile(const std::string& content, const std::string& path,
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mode_t mode, uid_t owner, gid_t group) {
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int flags = O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW | O_BINARY;
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int fd = TEMP_FAILURE_RETRY(open(path.c_str(), flags, mode));
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if (fd == -1) {
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ALOGE("android::WriteStringToFile open failed: %s", strerror(errno));
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return false;
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}
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// We do an explicit fchmod here because we assume that the caller really
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// meant what they said and doesn't want the umask-influenced mode.
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if (fchmod(fd, mode) == -1) {
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ALOGE("android::WriteStringToFile fchmod failed: %s", strerror(errno));
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return CleanUpAfterFailedWrite(path);
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}
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if (fchown(fd, owner, group) == -1) {
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ALOGE("android::WriteStringToFile fchown failed: %s", strerror(errno));
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return CleanUpAfterFailedWrite(path);
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}
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if (!WriteStringToFd(content, fd)) {
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ALOGE("android::WriteStringToFile write failed: %s", strerror(errno));
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return CleanUpAfterFailedWrite(path);
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}
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close(fd);
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return true;
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}
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#endif
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bool WriteStringToFile(const std::string& content, const std::string& path) {
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int flags = O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW | O_BINARY;
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int fd = TEMP_FAILURE_RETRY(open(path.c_str(), flags, DEFFILEMODE));
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if (fd == -1) {
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return false;
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}
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bool result = WriteStringToFd(content, fd);
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close(fd);
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return result || CleanUpAfterFailedWrite(path);
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}
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bool ReadFully(int fd, void* data, size_t byte_count) {
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uint8_t* p = reinterpret_cast<uint8_t*>(data);
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size_t remaining = byte_count;
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while (remaining > 0) {
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ssize_t n = TEMP_FAILURE_RETRY(read(fd, p, remaining));
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if (n <= 0) return false;
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p += n;
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remaining -= n;
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}
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return true;
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}
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bool WriteFully(int fd, const void* data, size_t byte_count) {
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const uint8_t* p = reinterpret_cast<const uint8_t*>(data);
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size_t remaining = byte_count;
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while (remaining > 0) {
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ssize_t n = TEMP_FAILURE_RETRY(write(fd, p, remaining));
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if (n == -1) return false;
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p += n;
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remaining -= n;
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}
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return true;
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}
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} // namespace base
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} // namespace android
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