123 lines
3.4 KiB
C++
123 lines
3.4 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 "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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#define LOG_TAG "base.file"
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#include "cutils/log.h"
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#include "utils/Compat.h" // For TEMP_FAILURE_RETRY on Darwin.
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namespace android {
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namespace base {
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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 =
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TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
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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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TEMP_FAILURE_RETRY(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 fd = TEMP_FAILURE_RETRY(
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open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
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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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TEMP_FAILURE_RETRY(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 fd = TEMP_FAILURE_RETRY(
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open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
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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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TEMP_FAILURE_RETRY(close(fd));
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return result || CleanUpAfterFailedWrite(path);
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}
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} // namespace base
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} // namespace android
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