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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/process/launch.h"
#include <lib/fdio/limits.h>
#include <lib/fdio/namespace.h>
#include <lib/fdio/spawn.h>
#include <lib/fdio/util.h>
#include <lib/zx/job.h>
#include <unistd.h>
#include <zircon/processargs.h>
#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/fuchsia/default_job.h"
#include "base/fuchsia/file_utils.h"
#include "base/fuchsia/fuchsia_logging.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/scoped_generic.h"
#include "starboard/types.h"
namespace base {
namespace {
bool GetAppOutputInternal(const CommandLine& cmd_line,
bool include_stderr,
std::string* output,
int* exit_code) {
LaunchOptions options;
// LaunchProcess will automatically clone any stdio fd we do not explicitly
// map.
int pipe_fd[2];
if (pipe(pipe_fd) < 0)
return false;
options.fds_to_remap.emplace_back(pipe_fd[1], STDOUT_FILENO);
if (include_stderr)
options.fds_to_remap.emplace_back(pipe_fd[1], STDERR_FILENO);
Process process = LaunchProcess(cmd_line, options);
if (!process.IsValid()) {
return false;
for (;;) {
char buffer[256];
ssize_t bytes_read = read(pipe_fd[0], buffer, sizeof(buffer));
if (bytes_read <= 0)
output->append(buffer, bytes_read);
return process.WaitForExit(exit_code);
fdio_spawn_action_t FdioSpawnAction(uint32_t action) {
fdio_spawn_action_t new_action = {};
new_action.action = action;
return new_action;
fdio_spawn_action_t FdioSpawnActionCloneFd(int local_fd, int target_fd) {
fdio_spawn_action_t action = FdioSpawnAction(FDIO_SPAWN_ACTION_CLONE_FD);
action.fd.local_fd = local_fd;
action.fd.target_fd = target_fd;
return action;
fdio_spawn_action_t FdioSpawnActionAddNamespaceEntry(const char* prefix,
zx_handle_t handle) {
fdio_spawn_action_t action = FdioSpawnAction(FDIO_SPAWN_ACTION_ADD_NS_ENTRY);
action.ns.prefix = prefix;
action.ns.handle = handle;
return action;
fdio_spawn_action_t FdioSpawnActionAddHandle(uint32_t id, zx_handle_t handle) {
fdio_spawn_action_t action = FdioSpawnAction(FDIO_SPAWN_ACTION_ADD_HANDLE); = id;
action.h.handle = handle;
return action;
} // namespace
Process LaunchProcess(const CommandLine& cmdline,
const LaunchOptions& options) {
return LaunchProcess(cmdline.argv(), options);
// TODO(768416): Investigate whether we can make LaunchProcess() create
// unprivileged processes by default (no implicit capabilities are granted).
Process LaunchProcess(const std::vector<std::string>& argv,
const LaunchOptions& options) {
// fdio_spawn_etc() accepts an array of |fdio_spawn_action_t|, describing
// namespace entries, descriptors and handles to launch the child process
// with.
std::vector<fdio_spawn_action_t> spawn_actions;
// Handles to be transferred to the child are owned by this vector, so that
// they they are closed on early-exit, and can be release()d otherwise.
std::vector<zx::handle> transferred_handles;
// Add caller-supplied handles for transfer. We must do this first to ensure
// that the handles are consumed even if some later step fails.
for (const auto& id_and_handle : options.handles_to_transfer) {
FdioSpawnActionAddHandle(, id_and_handle.handle));
// Determine the job under which to launch the new process.
zx::unowned_job job = options.job_handle != ZX_HANDLE_INVALID
? zx::unowned_job(options.job_handle)
: GetDefaultJob();
// Construct an |argv| array of C-strings from the supplied std::strings.
std::vector<const char*> argv_cstr;
argv_cstr.reserve(argv.size() + 1);
for (const auto& arg : argv)
// Determine the environment to pass to the new process.
// If |clear_environ|, |environ| or |current_directory| are set then we
// construct a new (possibly empty) environment, otherwise we let fdio_spawn()
// clone the caller's environment into the new process.
uint32_t spawn_flags = FDIO_SPAWN_CLONE_LDSVC | options.spawn_flags;
EnvironmentMap environ_modifications = options.environ;
if (!options.current_directory.empty()) {
environ_modifications["PWD"] = options.current_directory.value();
} else {
FilePath cwd;
environ_modifications["PWD"] = cwd.value();
std::unique_ptr<char* []> new_environ;
if (!environ_modifications.empty()) {
char* const empty_environ = nullptr;
char* const* old_environ = options.clear_environ ? &empty_environ : environ;
new_environ = AlterEnvironment(old_environ, environ_modifications);
} else if (!options.clear_environ) {
// Add actions to clone handles for any specified paths into the new process'
// namespace.
if (!options.paths_to_clone.empty() || !options.paths_to_transfer.empty()) {
DCHECK((options.spawn_flags & FDIO_SPAWN_CLONE_NAMESPACE) == 0);
transferred_handles.reserve(transferred_handles.size() +
options.paths_to_clone.size() +
for (const auto& path_to_transfer : options.paths_to_transfer) {
zx::handle handle(path_to_transfer.handle);
path_to_transfer.path.value().c_str(), handle.get()));
for (const auto& path_to_clone : options.paths_to_clone) {
zx::handle handle = fuchsia::GetHandleFromFile(
base::File::FLAG_OPEN | base::File::FLAG_READ));
if (!handle) {
LOG(WARNING) << "Could not open handle for path: " << path_to_clone;
return base::Process();
path_to_clone.value().c_str(), handle.get()));
// Add any file-descriptors to be cloned into the new process.
// Note that if FDIO_SPAWN_CLONE_STDIO is set, then any stdio entries in
// |fds_to_remap| will be used in place of the parent process' descriptors.
for (const auto& src_target : options.fds_to_remap) {
FdioSpawnActionCloneFd(src_target.first, src_target.second));
zx::process process_handle;
// fdio_spawn_etc() will write a null-terminated scring to |error_message| in
// case of failure, so we avoid unnecessarily initializing it here.
char error_message[FDIO_SPAWN_ERR_MSG_MAX_LENGTH];
zx_status_t status = fdio_spawn_etc(
job->get(), spawn_flags, argv_cstr[0],,
new_environ.get(), spawn_actions.size(),,
process_handle.reset_and_get_address(), error_message);
// fdio_spawn_etc() will close all handles specified in add-handle actions,
// regardless of whether it succeeds or fails, so release our copies.
for (auto& transferred_handle : transferred_handles)
if (status != ZX_OK) {
ZX_LOG(ERROR, status) << "fdio_spawn: " << error_message;
return Process();
// Wrap the handle into a Process, and wait for it to terminate, if requested.
Process process(process_handle.release());
if (options.wait) {
status = zx_object_wait_one(process.Handle(), ZX_TASK_TERMINATED,
ZX_DCHECK(status == ZX_OK, status) << "zx_object_wait_one";
return process;
bool GetAppOutput(const CommandLine& cl, std::string* output) {
int exit_code;
bool result = GetAppOutputInternal(cl, false, output, &exit_code);
return result && exit_code == EXIT_SUCCESS;
bool GetAppOutput(const std::vector<std::string>& argv, std::string* output) {
return GetAppOutput(CommandLine(argv), output);
bool GetAppOutputAndError(const CommandLine& cl, std::string* output) {
int exit_code;
bool result = GetAppOutputInternal(cl, true, output, &exit_code);
return result && exit_code == EXIT_SUCCESS;
bool GetAppOutputAndError(const std::vector<std::string>& argv,
std::string* output) {
return GetAppOutputAndError(CommandLine(argv), output);
bool GetAppOutputWithExitCode(const CommandLine& cl,
std::string* output,
int* exit_code) {
// Contrary to GetAppOutput(), |true| return here means that the process was
// launched and the exit code was waited upon successfully, but not
// necessarily that the exit code was EXIT_SUCCESS.
return GetAppOutputInternal(cl, false, output, exit_code);
void RaiseProcessToHighPriority() {
// Fuchsia doesn't provide an API to change process priority.
} // namespace base