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platform_system_core/init/service.cpp

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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "service.h"
#include <fcntl.h>
#include <inttypes.h>
#include <linux/securebits.h>
#include <sched.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <termios.h>
#include <unistd.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/scopeguard.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <cutils/sockets.h>
#include <processgroup/processgroup.h>
#include <selinux/selinux.h>
#include "lmkd_service.h"
#include "service_list.h"
#include "util.h"
#ifdef INIT_FULL_SOURCES
#include <ApexProperties.sysprop.h>
#include <android/api-level.h>
#include "mount_namespace.h"
#include "reboot_utils.h"
#include "selinux.h"
#else
#include "host_init_stubs.h"
#endif
using android::base::boot_clock;
using android::base::GetBoolProperty;
using android::base::GetProperty;
using android::base::Join;
using android::base::make_scope_guard;
using android::base::SetProperty;
using android::base::StartsWith;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
namespace android {
namespace init {
static Result<std::string> ComputeContextFromExecutable(const std::string& service_path) {
std::string computed_context;
char* raw_con = nullptr;
char* raw_filecon = nullptr;
if (getcon(&raw_con) == -1) {
return Error() << "Could not get security context";
}
std::unique_ptr<char, decltype(&freecon)> mycon(raw_con, freecon);
if (getfilecon(service_path.c_str(), &raw_filecon) == -1) {
return Error() << "Could not get file context";
}
std::unique_ptr<char, decltype(&freecon)> filecon(raw_filecon, freecon);
char* new_con = nullptr;
int rc = security_compute_create(mycon.get(), filecon.get(),
string_to_security_class("process"), &new_con);
if (rc == 0) {
computed_context = new_con;
free(new_con);
}
if (rc == 0 && computed_context == mycon.get()) {
return Error() << "File " << service_path << "(labeled \"" << filecon.get()
<< "\") has incorrect label or no domain transition from " << mycon.get()
<< " to another SELinux domain defined. Have you configured your "
"service correctly? https://source.android.com/security/selinux/"
"device-policy#label_new_services_and_address_denials. Note: this "
"error shows up even in permissive mode in order to make auditing "
"denials possible.";
}
if (rc < 0) {
return Error() << "Could not get process context";
}
return computed_context;
}
static bool ExpandArgsAndExecv(const std::vector<std::string>& args, bool sigstop) {
std::vector<std::string> expanded_args;
std::vector<char*> c_strings;
expanded_args.resize(args.size());
c_strings.push_back(const_cast<char*>(args[0].data()));
for (std::size_t i = 1; i < args.size(); ++i) {
auto expanded_arg = ExpandProps(args[i]);
if (!expanded_arg.ok()) {
LOG(FATAL) << args[0] << ": cannot expand arguments': " << expanded_arg.error();
}
expanded_args[i] = *expanded_arg;
c_strings.push_back(expanded_args[i].data());
}
c_strings.push_back(nullptr);
if (sigstop) {
kill(getpid(), SIGSTOP);
}
return execv(c_strings[0], c_strings.data()) == 0;
}
static bool AreRuntimeApexesReady() {
struct stat buf;
return stat("/apex/com.android.art/", &buf) == 0 &&
stat("/apex/com.android.runtime/", &buf) == 0;
}
unsigned long Service::next_start_order_ = 1;
bool Service::is_exec_service_running_ = false;
Service::Service(const std::string& name, Subcontext* subcontext_for_restart_commands,
const std::vector<std::string>& args, bool from_apex)
: Service(name, 0, 0, 0, {}, 0, "", subcontext_for_restart_commands, args, from_apex) {}
Service::Service(const std::string& name, unsigned flags, uid_t uid, gid_t gid,
const std::vector<gid_t>& supp_gids, int namespace_flags,
const std::string& seclabel, Subcontext* subcontext_for_restart_commands,
const std::vector<std::string>& args, bool from_apex)
: name_(name),
classnames_({"default"}),
flags_(flags),
pid_(0),
crash_count_(0),
proc_attr_{.ioprio_class = IoSchedClass_NONE,
.ioprio_pri = 0,
.uid = uid,
.gid = gid,
.supp_gids = supp_gids,
.priority = 0},
namespaces_{.flags = namespace_flags},
seclabel_(seclabel),
subcontext_(subcontext_for_restart_commands),
onrestart_(false, subcontext_for_restart_commands, "<Service '" + name + "' onrestart>", 0,
"onrestart", {}),
oom_score_adjust_(DEFAULT_OOM_SCORE_ADJUST),
start_order_(0),
args_(args),
from_apex_(from_apex) {}
void Service::NotifyStateChange(const std::string& new_state) const {
if ((flags_ & SVC_TEMPORARY) != 0) {
// Services created by 'exec' are temporary and don't have properties tracking their state.
return;
}
std::string prop_name = "init.svc." + name_;
SetProperty(prop_name, new_state);
if (new_state == "running") {
uint64_t start_ns = time_started_.time_since_epoch().count();
std::string boottime_property = "ro.boottime." + name_;
if (GetProperty(boottime_property, "").empty()) {
SetProperty(boottime_property, std::to_string(start_ns));
}
}
// init.svc_debug_pid.* properties are only for tests, and should not be used
// on device for security checks.
std::string pid_property = "init.svc_debug_pid." + name_;
if (new_state == "running") {
SetProperty(pid_property, std::to_string(pid_));
} else if (new_state == "stopped") {
SetProperty(pid_property, "");
}
}
void Service::KillProcessGroup(int signal, bool report_oneshot) {
// If we've already seen a successful result from killProcessGroup*(), then we have removed
// the cgroup already and calling these functions a second time will simply result in an error.
// This is true regardless of which signal was sent.
// These functions handle their own logging, so no additional logging is needed.
if (!process_cgroup_empty_) {
LOG(INFO) << "Sending signal " << signal << " to service '" << name_ << "' (pid " << pid_
<< ") process group...";
int max_processes = 0;
int r;
if (signal == SIGTERM) {
r = killProcessGroupOnce(proc_attr_.uid, pid_, signal, &max_processes);
} else {
r = killProcessGroup(proc_attr_.uid, pid_, signal, &max_processes);
}
if (report_oneshot && max_processes > 0) {
LOG(WARNING)
<< "Killed " << max_processes
<< " additional processes from a oneshot process group for service '" << name_
<< "'. This is new behavior, previously child processes would not be killed in "
"this case.";
}
if (r == 0) process_cgroup_empty_ = true;
}
if (oom_score_adjust_ != DEFAULT_OOM_SCORE_ADJUST) {
LmkdUnregister(name_, pid_);
}
}
void Service::SetProcessAttributesAndCaps() {
// Keep capabilites on uid change.
if (capabilities_ && proc_attr_.uid) {
// If Android is running in a container, some securebits might already
// be locked, so don't change those.
unsigned long securebits = prctl(PR_GET_SECUREBITS);
if (securebits == -1UL) {
PLOG(FATAL) << "prctl(PR_GET_SECUREBITS) failed for " << name_;
}
securebits |= SECBIT_KEEP_CAPS | SECBIT_KEEP_CAPS_LOCKED;
if (prctl(PR_SET_SECUREBITS, securebits) != 0) {
PLOG(FATAL) << "prctl(PR_SET_SECUREBITS) failed for " << name_;
}
}
if (auto result = SetProcessAttributes(proc_attr_); !result.ok()) {
LOG(FATAL) << "cannot set attribute for " << name_ << ": " << result.error();
}
if (!seclabel_.empty()) {
if (setexeccon(seclabel_.c_str()) < 0) {
PLOG(FATAL) << "cannot setexeccon('" << seclabel_ << "') for " << name_;
}
}
if (capabilities_) {
if (!SetCapsForExec(*capabilities_)) {
LOG(FATAL) << "cannot set capabilities for " << name_;
}
} else if (proc_attr_.uid) {
// Inheritable caps can be non-zero when running in a container.
if (!DropInheritableCaps()) {
LOG(FATAL) << "cannot drop inheritable caps for " << name_;
}
}
}
void Service::Reap(const siginfo_t& siginfo) {
if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) {
KillProcessGroup(SIGKILL, false);
} else {
// Legacy behavior from ~2007 until Android R: this else branch did not exist and we did not
// kill the process group in this case.
if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__) {
// The new behavior in Android R is to kill these process groups in all cases. The
// 'true' parameter instructions KillProcessGroup() to report a warning message where it
// detects a difference in behavior has occurred.
KillProcessGroup(SIGKILL, true);
}
}
// Remove any socket resources we may have created.
for (const auto& socket : sockets_) {
auto path = ANDROID_SOCKET_DIR "/" + socket.name;
unlink(path.c_str());
}
for (const auto& f : reap_callbacks_) {
f(siginfo);
}
if ((siginfo.si_code != CLD_EXITED || siginfo.si_status != 0) && on_failure_reboot_target_) {
LOG(ERROR) << "Service with 'reboot_on_failure' option failed, shutting down system.";
trigger_shutdown(*on_failure_reboot_target_);
}
if (flags_ & SVC_EXEC) UnSetExec();
if (flags_ & SVC_TEMPORARY) return;
pid_ = 0;
flags_ &= (~SVC_RUNNING);
start_order_ = 0;
// Oneshot processes go into the disabled state on exit,
// except when manually restarted.
if ((flags_ & SVC_ONESHOT) && !(flags_ & SVC_RESTART) && !(flags_ & SVC_RESET)) {
flags_ |= SVC_DISABLED;
}
// Disabled and reset processes do not get restarted automatically.
if (flags_ & (SVC_DISABLED | SVC_RESET)) {
NotifyStateChange("stopped");
return;
}
#if INIT_FULL_SOURCES
static bool is_apex_updatable = android::sysprop::ApexProperties::updatable().value_or(false);
#else
static bool is_apex_updatable = false;
#endif
const bool is_process_updatable = !pre_apexd_ && is_apex_updatable;
// If we crash > 4 times in 'fatal_crash_window_' minutes or before boot_completed,
// reboot into bootloader or set crashing property
boot_clock::time_point now = boot_clock::now();
if (((flags_ & SVC_CRITICAL) || is_process_updatable) && !(flags_ & SVC_RESTART)) {
bool boot_completed = GetBoolProperty("sys.boot_completed", false);
if (now < time_crashed_ + fatal_crash_window_ || !boot_completed) {
if (++crash_count_ > 4) {
auto exit_reason = boot_completed ?
"in " + std::to_string(fatal_crash_window_.count()) + " minutes" :
"before boot completed";
if (flags_ & SVC_CRITICAL) {
if (!GetBoolProperty("init.svc_debug.no_fatal." + name_, false)) {
// Aborts into `fatal_reboot_target_'.
SetFatalRebootTarget(fatal_reboot_target_);
LOG(FATAL) << "critical process '" << name_ << "' exited 4 times "
<< exit_reason;
}
} else {
LOG(ERROR) << "process with updatable components '" << name_
<< "' exited 4 times " << exit_reason;
// Notifies update_verifier and apexd
SetProperty("sys.init.updatable_crashing_process_name", name_);
SetProperty("sys.init.updatable_crashing", "1");
}
}
} else {
time_crashed_ = now;
crash_count_ = 1;
}
}
flags_ &= (~SVC_RESTART);
flags_ |= SVC_RESTARTING;
// Execute all onrestart commands for this service.
onrestart_.ExecuteAllCommands();
NotifyStateChange("restarting");
return;
}
void Service::DumpState() const {
LOG(INFO) << "service " << name_;
LOG(INFO) << " class '" << Join(classnames_, " ") << "'";
LOG(INFO) << " exec " << Join(args_, " ");
for (const auto& socket : sockets_) {
LOG(INFO) << " socket " << socket.name;
}
for (const auto& file : files_) {
LOG(INFO) << " file " << file.name;
}
}
Result<void> Service::ExecStart() {
auto reboot_on_failure = make_scope_guard([this] {
if (on_failure_reboot_target_) {
trigger_shutdown(*on_failure_reboot_target_);
}
});
if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
// Don't delay the service for ExecStart() as the semantic is that
// the caller might depend on the side effect of the execution.
return Error() << "Cannot start an updatable service '" << name_
<< "' before configs from APEXes are all loaded";
}
flags_ |= SVC_ONESHOT;
if (auto result = Start(); !result.ok()) {
return result;
}
flags_ |= SVC_EXEC;
is_exec_service_running_ = true;
LOG(INFO) << "SVC_EXEC service '" << name_ << "' pid " << pid_ << " (uid " << proc_attr_.uid
<< " gid " << proc_attr_.gid << "+" << proc_attr_.supp_gids.size() << " context "
<< (!seclabel_.empty() ? seclabel_ : "default") << ") started; waiting...";
reboot_on_failure.Disable();
return {};
}
Result<void> Service::Start() {
auto reboot_on_failure = make_scope_guard([this] {
if (on_failure_reboot_target_) {
trigger_shutdown(*on_failure_reboot_target_);
}
});
if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
ServiceList::GetInstance().DelayService(*this);
return Error() << "Cannot start an updatable service '" << name_
<< "' before configs from APEXes are all loaded. "
<< "Queued for execution.";
}
bool disabled = (flags_ & (SVC_DISABLED | SVC_RESET));
// Starting a service removes it from the disabled or reset state and
// immediately takes it out of the restarting state if it was in there.
flags_ &= (~(SVC_DISABLED|SVC_RESTARTING|SVC_RESET|SVC_RESTART|SVC_DISABLED_START));
// Running processes require no additional work --- if they're in the
// process of exiting, we've ensured that they will immediately restart
// on exit, unless they are ONESHOT. For ONESHOT service, if it's in
// stopping status, we just set SVC_RESTART flag so it will get restarted
// in Reap().
if (flags_ & SVC_RUNNING) {
if ((flags_ & SVC_ONESHOT) && disabled) {
flags_ |= SVC_RESTART;
}
// It is not an error to try to start a service that is already running.
reboot_on_failure.Disable();
return {};
}
bool needs_console = (flags_ & SVC_CONSOLE);
if (needs_console) {
if (proc_attr_.console.empty()) {
proc_attr_.console = "/dev/" + GetProperty("ro.boot.console", "console");
}
// Make sure that open call succeeds to ensure a console driver is
// properly registered for the device node
int console_fd = open(proc_attr_.console.c_str(), O_RDWR | O_CLOEXEC);
if (console_fd < 0) {
flags_ |= SVC_DISABLED;
return ErrnoError() << "Couldn't open console '" << proc_attr_.console << "'";
}
close(console_fd);
}
struct stat sb;
if (stat(args_[0].c_str(), &sb) == -1) {
flags_ |= SVC_DISABLED;
return ErrnoError() << "Cannot find '" << args_[0] << "'";
}
std::string scon;
if (!seclabel_.empty()) {
scon = seclabel_;
} else {
auto result = ComputeContextFromExecutable(args_[0]);
if (!result.ok()) {
return result.error();
}
scon = *result;
}
if (!AreRuntimeApexesReady() && !pre_apexd_) {
// If this service is started before the Runtime and ART APEXes get
// available, mark it as pre-apexd one. Note that this marking is
// permanent. So for example, if the service is re-launched (e.g., due
// to crash), it is still recognized as pre-apexd... for consistency.
pre_apexd_ = true;
}
// For pre-apexd services, override mount namespace as "bootstrap" one before starting.
// Note: "ueventd" is supposed to be run in "default" mount namespace even if it's pre-apexd
// to support loading firmwares from APEXes.
std::optional<MountNamespace> override_mount_namespace;
if (name_ == "ueventd") {
override_mount_namespace = NS_DEFAULT;
} else if (pre_apexd_) {
override_mount_namespace = NS_BOOTSTRAP;
}
post_data_ = ServiceList::GetInstance().IsPostData();
LOG(INFO) << "starting service '" << name_ << "'...";
std::vector<Descriptor> descriptors;
for (const auto& socket : sockets_) {
if (auto result = socket.Create(scon); result.ok()) {
descriptors.emplace_back(std::move(*result));
} else {
LOG(INFO) << "Could not create socket '" << socket.name << "': " << result.error();
}
}
for (const auto& file : files_) {
if (auto result = file.Create(); result.ok()) {
descriptors.emplace_back(std::move(*result));
} else {
LOG(INFO) << "Could not open file '" << file.name << "': " << result.error();
}
}
pid_t pid = -1;
if (namespaces_.flags) {
pid = clone(nullptr, nullptr, namespaces_.flags | SIGCHLD, nullptr);
} else {
pid = fork();
}
if (pid == 0) {
umask(077);
if (auto result = EnterNamespaces(namespaces_, name_, override_mount_namespace);
!result.ok()) {
LOG(FATAL) << "Service '" << name_
<< "' failed to set up namespaces: " << result.error();
}
for (const auto& [key, value] : environment_vars_) {
setenv(key.c_str(), value.c_str(), 1);
}
for (const auto& descriptor : descriptors) {
descriptor.Publish();
}
if (auto result = WritePidToFiles(&writepid_files_); !result.ok()) {
LOG(ERROR) << "failed to write pid to files: " << result.error();
}
if (task_profiles_.size() > 0 && !SetTaskProfiles(getpid(), task_profiles_)) {
LOG(ERROR) << "failed to set task profiles";
}
// As requested, set our gid, supplemental gids, uid, context, and
// priority. Aborts on failure.
SetProcessAttributesAndCaps();
if (!ExpandArgsAndExecv(args_, sigstop_)) {
PLOG(ERROR) << "cannot execv('" << args_[0]
<< "'). See the 'Debugging init' section of init's README.md for tips";
}
_exit(127);
}
if (pid < 0) {
pid_ = 0;
return ErrnoError() << "Failed to fork";
}
if (oom_score_adjust_ != DEFAULT_OOM_SCORE_ADJUST) {
std::string oom_str = std::to_string(oom_score_adjust_);
std::string oom_file = StringPrintf("/proc/%d/oom_score_adj", pid);
if (!WriteStringToFile(oom_str, oom_file)) {
PLOG(ERROR) << "couldn't write oom_score_adj";
}
}
time_started_ = boot_clock::now();
pid_ = pid;
flags_ |= SVC_RUNNING;
start_order_ = next_start_order_++;
process_cgroup_empty_ = false;
bool use_memcg = swappiness_ != -1 || soft_limit_in_bytes_ != -1 || limit_in_bytes_ != -1 ||
limit_percent_ != -1 || !limit_property_.empty();
errno = -createProcessGroup(proc_attr_.uid, pid_, use_memcg);
if (errno != 0) {
PLOG(ERROR) << "createProcessGroup(" << proc_attr_.uid << ", " << pid_
<< ") failed for service '" << name_ << "'";
} else if (use_memcg) {
if (swappiness_ != -1) {
if (!setProcessGroupSwappiness(proc_attr_.uid, pid_, swappiness_)) {
PLOG(ERROR) << "setProcessGroupSwappiness failed";
}
}
if (soft_limit_in_bytes_ != -1) {
if (!setProcessGroupSoftLimit(proc_attr_.uid, pid_, soft_limit_in_bytes_)) {
PLOG(ERROR) << "setProcessGroupSoftLimit failed";
}
}
size_t computed_limit_in_bytes = limit_in_bytes_;
if (limit_percent_ != -1) {
long page_size = sysconf(_SC_PAGESIZE);
long num_pages = sysconf(_SC_PHYS_PAGES);
if (page_size > 0 && num_pages > 0) {
size_t max_mem = SIZE_MAX;
if (size_t(num_pages) < SIZE_MAX / size_t(page_size)) {
max_mem = size_t(num_pages) * size_t(page_size);
}
computed_limit_in_bytes =
std::min(computed_limit_in_bytes, max_mem / 100 * limit_percent_);
}
}
if (!limit_property_.empty()) {
// This ends up overwriting computed_limit_in_bytes but only if the
// property is defined.
computed_limit_in_bytes = android::base::GetUintProperty(
limit_property_, computed_limit_in_bytes, SIZE_MAX);
}
if (computed_limit_in_bytes != size_t(-1)) {
if (!setProcessGroupLimit(proc_attr_.uid, pid_, computed_limit_in_bytes)) {
PLOG(ERROR) << "setProcessGroupLimit failed";
}
}
}
if (oom_score_adjust_ != DEFAULT_OOM_SCORE_ADJUST) {
LmkdRegister(name_, proc_attr_.uid, pid_, oom_score_adjust_);
}
NotifyStateChange("running");
reboot_on_failure.Disable();
return {};
}
Result<void> Service::StartIfNotDisabled() {
if (!(flags_ & SVC_DISABLED)) {
return Start();
} else {
flags_ |= SVC_DISABLED_START;
}
return {};
}
Result<void> Service::Enable() {
flags_ &= ~(SVC_DISABLED | SVC_RC_DISABLED);
if (flags_ & SVC_DISABLED_START) {
return Start();
}
return {};
}
void Service::Reset() {
StopOrReset(SVC_RESET);
}
void Service::ResetIfPostData() {
if (post_data_) {
if (flags_ & SVC_RUNNING) {
running_at_post_data_reset_ = true;
}
StopOrReset(SVC_RESET);
}
}
Result<void> Service::StartIfPostData() {
// Start the service, but only if it was started after /data was mounted,
// and it was still running when we reset the post-data services.
if (running_at_post_data_reset_) {
return Start();
}
return {};
}
void Service::Stop() {
StopOrReset(SVC_DISABLED);
}
void Service::Terminate() {
flags_ &= ~(SVC_RESTARTING | SVC_DISABLED_START);
flags_ |= SVC_DISABLED;
if (pid_) {
KillProcessGroup(SIGTERM);
NotifyStateChange("stopping");
}
}
void Service::Timeout() {
// All process state flags will be taken care of in Reap(), we really just want to kill the
// process here when it times out. Oneshot processes will transition to be disabled, and
// all other processes will transition to be restarting.
LOG(INFO) << "Service '" << name_ << "' expired its timeout of " << timeout_period_->count()
<< " seconds and will now be killed";
if (pid_) {
KillProcessGroup(SIGKILL);
NotifyStateChange("stopping");
}
}
void Service::Restart() {
if (flags_ & SVC_RUNNING) {
/* Stop, wait, then start the service. */
StopOrReset(SVC_RESTART);
} else if (!(flags_ & SVC_RESTARTING)) {
/* Just start the service since it's not running. */
if (auto result = Start(); !result.ok()) {
LOG(ERROR) << "Could not restart '" << name_ << "': " << result.error();
}
} /* else: Service is restarting anyways. */
}
// The how field should be either SVC_DISABLED, SVC_RESET, or SVC_RESTART.
void Service::StopOrReset(int how) {
// The service is still SVC_RUNNING until its process exits, but if it has
// already exited it shoudn't attempt a restart yet.
flags_ &= ~(SVC_RESTARTING | SVC_DISABLED_START);
if ((how != SVC_DISABLED) && (how != SVC_RESET) && (how != SVC_RESTART)) {
// An illegal flag: default to SVC_DISABLED.
how = SVC_DISABLED;
}
// If the service has not yet started, prevent it from auto-starting with its class.
if (how == SVC_RESET) {
flags_ |= (flags_ & SVC_RC_DISABLED) ? SVC_DISABLED : SVC_RESET;
} else {
flags_ |= how;
}
// Make sure it's in right status when a restart immediately follow a
// stop/reset or vice versa.
if (how == SVC_RESTART) {
flags_ &= (~(SVC_DISABLED | SVC_RESET));
} else {
flags_ &= (~SVC_RESTART);
}
if (pid_) {
KillProcessGroup(SIGKILL);
NotifyStateChange("stopping");
} else {
NotifyStateChange("stopped");
}
}
Result<std::unique_ptr<Service>> Service::MakeTemporaryOneshotService(
const std::vector<std::string>& args) {
// Parse the arguments: exec [SECLABEL [UID [GID]*] --] COMMAND ARGS...
// SECLABEL can be a - to denote default
std::size_t command_arg = 1;
for (std::size_t i = 1; i < args.size(); ++i) {
if (args[i] == "--") {
command_arg = i + 1;
break;
}
}
if (command_arg > 4 + NR_SVC_SUPP_GIDS) {
return Error() << "exec called with too many supplementary group ids";
}
if (command_arg >= args.size()) {
return Error() << "exec called without command";
}
std::vector<std::string> str_args(args.begin() + command_arg, args.end());
static size_t exec_count = 0;
exec_count++;
std::string name = "exec " + std::to_string(exec_count) + " (" + Join(str_args, " ") + ")";
unsigned flags = SVC_ONESHOT | SVC_TEMPORARY;
unsigned namespace_flags = 0;
std::string seclabel = "";
if (command_arg > 2 && args[1] != "-") {
seclabel = args[1];
}
Result<uid_t> uid = 0;
if (command_arg > 3) {
uid = DecodeUid(args[2]);
if (!uid.ok()) {
return Error() << "Unable to decode UID for '" << args[2] << "': " << uid.error();
}
}
Result<gid_t> gid = 0;
std::vector<gid_t> supp_gids;
if (command_arg > 4) {
gid = DecodeUid(args[3]);
if (!gid.ok()) {
return Error() << "Unable to decode GID for '" << args[3] << "': " << gid.error();
}
std::size_t nr_supp_gids = command_arg - 1 /* -- */ - 4 /* exec SECLABEL UID GID */;
for (size_t i = 0; i < nr_supp_gids; ++i) {
auto supp_gid = DecodeUid(args[4 + i]);
if (!supp_gid.ok()) {
return Error() << "Unable to decode GID for '" << args[4 + i]
<< "': " << supp_gid.error();
}
supp_gids.push_back(*supp_gid);
}
}
return std::make_unique<Service>(name, flags, *uid, *gid, supp_gids, namespace_flags, seclabel,
nullptr, str_args, false);
}
} // namespace init
} // namespace android
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