Move ForkExecveAndWaitForCompletion to util.h (fe7b83fa) · Commits · e / os / android_system_core

init/selinux.cpp

+0 −91

Original line number	Diff line number	Diff line
		@@ -111,97 +111,6 @@ bool IsEnforcing() {
		return true;
		}

		// Forks, executes the provided program in the child, and waits for the completion in the parent.
		// Child's stderr is captured and logged using LOG(ERROR).
		bool ForkExecveAndWaitForCompletion(const char* filename, char* const argv[]) {
		// Create a pipe used for redirecting child process's output.
		// * pipe_fds[0] is the FD the parent will use for reading.
		// * pipe_fds[1] is the FD the child will use for writing.
		int pipe_fds[2];
		if (pipe(pipe_fds) == -1) {
		PLOG(ERROR) << "Failed to create pipe";
		return false;
		}

		pid_t child_pid = fork();
		if (child_pid == -1) {
		PLOG(ERROR) << "Failed to fork for " << filename;
		return false;
		}

		if (child_pid == 0) {
		// fork succeeded -- this is executing in the child process

		// Close the pipe FD not used by this process
		close(pipe_fds[0]);

		// Redirect stderr to the pipe FD provided by the parent
		if (TEMP_FAILURE_RETRY(dup2(pipe_fds[1], STDERR_FILENO)) == -1) {
		PLOG(ERROR) << "Failed to redirect stderr of " << filename;
		_exit(127);
		return false;
		}
		close(pipe_fds[1]);

		if (execv(filename, argv) == -1) {
		PLOG(ERROR) << "Failed to execve " << filename;
		return false;
		}
		// Unreachable because execve will have succeeded and replaced this code
		// with child process's code.
		_exit(127);
		return false;
		} else {
		// fork succeeded -- this is executing in the original/parent process

		// Close the pipe FD not used by this process
		close(pipe_fds[1]);

		// Log the redirected output of the child process.
		// It's unfortunate that there's no standard way to obtain an istream for a file descriptor.
		// As a result, we're buffering all output and logging it in one go at the end of the
		// invocation, instead of logging it as it comes in.
		const int child_out_fd = pipe_fds[0];
		std::string child_output;
		if (!android::base::ReadFdToString(child_out_fd, &child_output)) {
		PLOG(ERROR) << "Failed to capture full output of " << filename;
		}
		close(child_out_fd);
		if (!child_output.empty()) {
		// Log captured output, line by line, because LOG expects to be invoked for each line
		std::istringstream in(child_output);
		std::string line;
		while (std::getline(in, line)) {
		LOG(ERROR) << filename << ": " << line;
		}
		}

		// Wait for child to terminate
		int status;
		if (TEMP_FAILURE_RETRY(waitpid(child_pid, &status, 0)) != child_pid) {
		PLOG(ERROR) << "Failed to wait for " << filename;
		return false;
		}

		if (WIFEXITED(status)) {
		int status_code = WEXITSTATUS(status);
		if (status_code == 0) {
		return true;
		} else {
		LOG(ERROR) << filename << " exited with status " << status_code;
		}
		} else if (WIFSIGNALED(status)) {
		LOG(ERROR) << filename << " killed by signal " << WTERMSIG(status);
		} else if (WIFSTOPPED(status)) {
		LOG(ERROR) << filename << " stopped by signal " << WSTOPSIG(status);
		} else {
		LOG(ERROR) << "waitpid for " << filename << " returned unexpected status: " << status;
		}

		return false;
		}
		}

		bool ReadFirstLine(const char* file, std::string* line) {
		line->clear();

init/util.cpp

+92 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <string.h>
		#include <sys/socket.h>
		#include <sys/un.h>
		#include <sys/wait.h>
		#include <time.h>
		#include <unistd.h>

		@@ -747,5 +748,96 @@ std::vector<std::string> FilterVersionedConfigs(const std::vector<std::string>&
		return filtered_configs;
		}

		// Forks, executes the provided program in the child, and waits for the completion in the parent.
		// Child's stderr is captured and logged using LOG(ERROR).
		bool ForkExecveAndWaitForCompletion(const char* filename, char* const argv[]) {
		// Create a pipe used for redirecting child process's output.
		// * pipe_fds[0] is the FD the parent will use for reading.
		// * pipe_fds[1] is the FD the child will use for writing.
		int pipe_fds[2];
		if (pipe(pipe_fds) == -1) {
		PLOG(ERROR) << "Failed to create pipe";
		return false;
		}

		pid_t child_pid = fork();
		if (child_pid == -1) {
		PLOG(ERROR) << "Failed to fork for " << filename;
		return false;
		}

		if (child_pid == 0) {
		// fork succeeded -- this is executing in the child process

		// Close the pipe FD not used by this process
		close(pipe_fds[0]);

		// Redirect stderr to the pipe FD provided by the parent
		if (TEMP_FAILURE_RETRY(dup2(pipe_fds[1], STDERR_FILENO)) == -1) {
		PLOG(ERROR) << "Failed to redirect stderr of " << filename;
		_exit(127);
		return false;
		}
		close(pipe_fds[1]);

		if (execv(filename, argv) == -1) {
		PLOG(ERROR) << "Failed to execve " << filename;
		return false;
		}
		// Unreachable because execve will have succeeded and replaced this code
		// with child process's code.
		_exit(127);
		return false;
		} else {
		// fork succeeded -- this is executing in the original/parent process

		// Close the pipe FD not used by this process
		close(pipe_fds[1]);

		// Log the redirected output of the child process.
		// It's unfortunate that there's no standard way to obtain an istream for a file descriptor.
		// As a result, we're buffering all output and logging it in one go at the end of the
		// invocation, instead of logging it as it comes in.
		const int child_out_fd = pipe_fds[0];
		std::string child_output;
		if (!android::base::ReadFdToString(child_out_fd, &child_output)) {
		PLOG(ERROR) << "Failed to capture full output of " << filename;
		}
		close(child_out_fd);
		if (!child_output.empty()) {
		// Log captured output, line by line, because LOG expects to be invoked for each line
		std::istringstream in(child_output);
		std::string line;
		while (std::getline(in, line)) {
		LOG(ERROR) << filename << ": " << line;
		}
		}

		// Wait for child to terminate
		int status;
		if (TEMP_FAILURE_RETRY(waitpid(child_pid, &status, 0)) != child_pid) {
		PLOG(ERROR) << "Failed to wait for " << filename;
		return false;
		}

		if (WIFEXITED(status)) {
		int status_code = WEXITSTATUS(status);
		if (status_code == 0) {
		return true;
		} else {
		LOG(ERROR) << filename << " exited with status " << status_code;
		}
		} else if (WIFSIGNALED(status)) {
		LOG(ERROR) << filename << " killed by signal " << WTERMSIG(status);
		} else if (WIFSTOPPED(status)) {
		LOG(ERROR) << filename << " stopped by signal " << WSTOPSIG(status);
		} else {
		LOG(ERROR) << "waitpid for " << filename << " returned unexpected status: " << status;
		}

		return false;
		}
		}

		} // namespace init
		} // namespace android

init/util.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -117,5 +117,10 @@ std::string GetApexNameFromFileName(const std::string& path);
		// (.rc == .0rc for ranking purposes)
		std::vector<std::string> FilterVersionedConfigs(const std::vector<std::string>& configs,
		int active_sdk);

		// Forks, executes the provided program in the child, and waits for the completion in the parent.
		// Child's stderr is captured and logged using LOG(ERROR).
		bool ForkExecveAndWaitForCompletion(const char* filename, char* const argv[]);

		} // namespace init
		} // namespace android