f682b4786a
This isn't particularly useful in and of itself, but it does introduce the first (trivial) unit test, improves the documentation (including details about how to debug init crashes), and made me aware of how unpleasant the existing parser is. I also fixed a bug in passing --- unless you thought the "peboot" and "pm" commands were features... Bug: 19217569 Change-Id: I6ab76129a543ce3ed3dab52ef2c638009874c3de
100 lines
3 KiB
C++
100 lines
3 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 "utils/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 <utils/Compat.h> // For TEMP_FAILURE_RETRY on Darwin.
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bool android::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 android::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));
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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 android::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 android::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(open(path.c_str(),
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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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return false;
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}
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// We do an explicit fchmod here because we assume that the caller really meant what they
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// said and doesn't want the umask-influenced mode.
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bool result = (fchmod(fd, mode) != -1 && fchown(fd, owner, group) == -1 && 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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#endif
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bool android::WriteStringToFile(const std::string& content, const std::string& path) {
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int fd = TEMP_FAILURE_RETRY(open(path.c_str(),
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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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