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platform_system_core/init/service.cpp
Tom Cherry cb0f9bbc85 init: run vendor commands in a separate SELinux context 
One of the major aspects of treble is the compartmentalization of system
and vendor components, however init leaves a huge gap here, as vendor
init scripts run in the same context as system init scripts and thus can
access and modify the same properties, files, etc as the system can.

This change is meant to close that gap.  It forks a separate 'subcontext'
init that runs in a different SELinux context with permissions that match
what vendors should have access to.  Commands get sent over a socket to
this 'subcontext' init that then runs them in this SELinux context and
returns the result.

Note that not all commands run in the subcontext; some commands such as
those dealing with services only make sense in the context of the main
init process.

Bug: 62875318
Test: init unit tests, boot bullhead, boot sailfish

Change-Id: Idf4a4ebf98842d27b8627f901f961ab9eb412aee
2017-09-29 13:06:26 -07:00

1093 lines
36 KiB
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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/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/system_properties.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <termios.h>
#include <unistd.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/scopeguard.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <processgroup/processgroup.h>
#include <selinux/selinux.h>
#include <system/thread_defs.h>
#include "init.h"
#include "property_service.h"
#include "rlimit_parser.h"
#include "util.h"
using android::base::boot_clock;
using android::base::GetProperty;
using android::base::Join;
using android::base::make_scope_guard;
using android::base::ParseInt;
using android::base::StartsWith;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
namespace android {
namespace init {
static Result<std::string> ComputeContextFromExecutable(std::string& service_name,
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> mycon(raw_con);
if (getfilecon(service_path.c_str(), &raw_filecon) == -1) {
return Error() << "Could not get file context";
}
std::unique_ptr<char> filecon(raw_filecon);
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";
}
if (rc < 0) {
return Error() << "Could not get process context";
}
return computed_context;
}
static void SetUpPidNamespace(const std::string& service_name) {
constexpr unsigned int kSafeFlags = MS_NODEV | MS_NOEXEC | MS_NOSUID;
// It's OK to LOG(FATAL) in this function since it's running in the first
// child process.
if (mount("", "/proc", "proc", kSafeFlags | MS_REMOUNT, "") == -1) {
PLOG(FATAL) << "couldn't remount(/proc) for " << service_name;
}
if (prctl(PR_SET_NAME, service_name.c_str()) == -1) {
PLOG(FATAL) << "couldn't set name for " << service_name;
}
pid_t child_pid = fork();
if (child_pid == -1) {
PLOG(FATAL) << "couldn't fork init inside the PID namespace for " << service_name;
}
if (child_pid > 0) {
// So that we exit with the right status.
static int init_exitstatus = 0;
signal(SIGTERM, [](int) { _exit(init_exitstatus); });
pid_t waited_pid;
int status;
while ((waited_pid = wait(&status)) > 0) {
// This loop will end when there are no processes left inside the
// PID namespace or when the init process inside the PID namespace
// gets a signal.
if (waited_pid == child_pid) {
init_exitstatus = status;
}
}
if (!WIFEXITED(init_exitstatus)) {
_exit(EXIT_FAILURE);
}
_exit(WEXITSTATUS(init_exitstatus));
}
}
static bool ExpandArgsAndExecv(const std::vector<std::string>& args) {
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) {
if (!expand_props(args[i], &expanded_args[i])) {
LOG(FATAL) << args[0] << ": cannot expand '" << args[i] << "'";
}
c_strings.push_back(expanded_args[i].data());
}
c_strings.push_back(nullptr);
return execv(c_strings[0], c_strings.data()) == 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)
: Service(name, 0, 0, 0, {}, 0, 0, "", subcontext_for_restart_commands, args) {}
Service::Service(const std::string& name, unsigned flags, uid_t uid, gid_t gid,
const std::vector<gid_t>& supp_gids, const CapSet& capabilities,
unsigned namespace_flags, const std::string& seclabel,
Subcontext* subcontext_for_restart_commands, const std::vector<std::string>& args)
: name_(name),
classnames_({"default"}),
flags_(flags),
pid_(0),
crash_count_(0),
uid_(uid),
gid_(gid),
supp_gids_(supp_gids),
capabilities_(capabilities),
namespace_flags_(namespace_flags),
seclabel_(seclabel),
onrestart_(false, subcontext_for_restart_commands, "<Service '" + name + "' onrestart>", 0),
keychord_id_(0),
ioprio_class_(IoSchedClass_NONE),
ioprio_pri_(0),
priority_(0),
oom_score_adjust_(-1000),
swappiness_(-1),
soft_limit_in_bytes_(-1),
limit_in_bytes_(-1),
start_order_(0),
args_(args) {
onrestart_.InitSingleTrigger("onrestart");
}
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_;
property_set(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()) {
property_set(boottime_property, std::to_string(start_ns));
}
}
}
void Service::KillProcessGroup(int signal) {
// 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 r;
if (signal == SIGTERM) {
r = killProcessGroupOnce(uid_, pid_, signal);
} else {
r = killProcessGroup(uid_, pid_, signal);
}
if (r == 0) process_cgroup_empty_ = true;
}
}
void Service::SetProcessAttributes() {
for (const auto& rlimit : rlimits_) {
if (setrlimit(rlimit.first, &rlimit.second) == -1) {
LOG(FATAL) << StringPrintf("setrlimit(%d, {rlim_cur=%ld, rlim_max=%ld}) failed",
rlimit.first, rlimit.second.rlim_cur, rlimit.second.rlim_max);
}
}
// Keep capabilites on uid change.
if (capabilities_.any() && 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_;
}
}
// TODO: work out why this fails for `console` then upgrade to FATAL.
if (setpgid(0, getpid()) == -1) PLOG(ERROR) << "setpgid failed for " << name_;
if (gid_) {
if (setgid(gid_) != 0) {
PLOG(FATAL) << "setgid failed for " << name_;
}
}
if (setgroups(supp_gids_.size(), &supp_gids_[0]) != 0) {
PLOG(FATAL) << "setgroups failed for " << name_;
}
if (uid_) {
if (setuid(uid_) != 0) {
PLOG(FATAL) << "setuid failed for " << name_;
}
}
if (!seclabel_.empty()) {
if (setexeccon(seclabel_.c_str()) < 0) {
PLOG(FATAL) << "cannot setexeccon('" << seclabel_ << "') for " << name_;
}
}
if (priority_ != 0) {
if (setpriority(PRIO_PROCESS, 0, priority_) != 0) {
PLOG(FATAL) << "setpriority failed for " << name_;
}
}
if (capabilities_.any()) {
if (!SetCapsForExec(capabilities_)) {
LOG(FATAL) << "cannot set capabilities for " << name_;
}
}
}
void Service::Reap() {
if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) {
KillProcessGroup(SIGKILL);
}
// Remove any descriptor resources we may have created.
std::for_each(descriptors_.begin(), descriptors_.end(),
std::bind(&DescriptorInfo::Clean, std::placeholders::_1));
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_DISABLED;
}
// Disabled and reset processes do not get restarted automatically.
if (flags_ & (SVC_DISABLED | SVC_RESET)) {
NotifyStateChange("stopped");
return;
}
// If we crash > 4 times in 4 minutes, reboot into recovery.
boot_clock::time_point now = boot_clock::now();
if ((flags_ & SVC_CRITICAL) && !(flags_ & SVC_RESTART)) {
if (now < time_crashed_ + 4min) {
if (++crash_count_ > 4) {
LOG(FATAL) << "critical process '" << name_ << "' exited 4 times in 4 minutes";
}
} 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_, " ");
std::for_each(descriptors_.begin(), descriptors_.end(),
[] (const auto& info) { LOG(INFO) << *info; });
}
Result<Success> Service::ParseCapabilities(const std::vector<std::string>& args) {
capabilities_ = 0;
if (!CapAmbientSupported()) {
return Error()
<< "capabilities requested but the kernel does not support ambient capabilities";
}
unsigned int last_valid_cap = GetLastValidCap();
if (last_valid_cap >= capabilities_.size()) {
LOG(WARNING) << "last valid run-time capability is larger than CAP_LAST_CAP";
}
for (size_t i = 1; i < args.size(); i++) {
const std::string& arg = args[i];
int res = LookupCap(arg);
if (res < 0) {
return Error() << StringPrintf("invalid capability '%s'", arg.c_str());
}
unsigned int cap = static_cast<unsigned int>(res); // |res| is >= 0.
if (cap > last_valid_cap) {
return Error() << StringPrintf("capability '%s' not supported by the kernel",
arg.c_str());
}
capabilities_[cap] = true;
}
return Success();
}
Result<Success> Service::ParseClass(const std::vector<std::string>& args) {
classnames_ = std::set<std::string>(args.begin() + 1, args.end());
return Success();
}
Result<Success> Service::ParseConsole(const std::vector<std::string>& args) {
flags_ |= SVC_CONSOLE;
console_ = args.size() > 1 ? "/dev/" + args[1] : "";
return Success();
}
Result<Success> Service::ParseCritical(const std::vector<std::string>& args) {
flags_ |= SVC_CRITICAL;
return Success();
}
Result<Success> Service::ParseDisabled(const std::vector<std::string>& args) {
flags_ |= SVC_DISABLED;
flags_ |= SVC_RC_DISABLED;
return Success();
}
Result<Success> Service::ParseGroup(const std::vector<std::string>& args) {
auto gid = DecodeUid(args[1]);
if (!gid) {
return Error() << "Unable to decode GID for '" << args[1] << "': " << gid.error();
}
gid_ = *gid;
for (std::size_t n = 2; n < args.size(); n++) {
gid = DecodeUid(args[n]);
if (!gid) {
return Error() << "Unable to decode GID for '" << args[n] << "': " << gid.error();
}
supp_gids_.emplace_back(*gid);
}
return Success();
}
Result<Success> Service::ParsePriority(const std::vector<std::string>& args) {
priority_ = 0;
if (!ParseInt(args[1], &priority_,
static_cast<int>(ANDROID_PRIORITY_HIGHEST), // highest is negative
static_cast<int>(ANDROID_PRIORITY_LOWEST))) {
return Error() << StringPrintf("process priority value must be range %d - %d",
ANDROID_PRIORITY_HIGHEST, ANDROID_PRIORITY_LOWEST);
}
return Success();
}
Result<Success> Service::ParseIoprio(const std::vector<std::string>& args) {
if (!ParseInt(args[2], &ioprio_pri_, 0, 7)) {
return Error() << "priority value must be range 0 - 7";
}
if (args[1] == "rt") {
ioprio_class_ = IoSchedClass_RT;
} else if (args[1] == "be") {
ioprio_class_ = IoSchedClass_BE;
} else if (args[1] == "idle") {
ioprio_class_ = IoSchedClass_IDLE;
} else {
return Error() << "ioprio option usage: ioprio <rt|be|idle> <0-7>";
}
return Success();
}
Result<Success> Service::ParseKeycodes(const std::vector<std::string>& args) {
for (std::size_t i = 1; i < args.size(); i++) {
int code;
if (ParseInt(args[i], &code)) {
keycodes_.emplace_back(code);
} else {
LOG(WARNING) << "ignoring invalid keycode: " << args[i];
}
}
return Success();
}
Result<Success> Service::ParseOneshot(const std::vector<std::string>& args) {
flags_ |= SVC_ONESHOT;
return Success();
}
Result<Success> Service::ParseOnrestart(const std::vector<std::string>& args) {
std::vector<std::string> str_args(args.begin() + 1, args.end());
int line = onrestart_.NumCommands() + 1;
if (auto result = onrestart_.AddCommand(str_args, line); !result) {
return Error() << "cannot add Onrestart command: " << result.error();
}
return Success();
}
Result<Success> Service::ParseNamespace(const std::vector<std::string>& args) {
for (size_t i = 1; i < args.size(); i++) {
if (args[i] == "pid") {
namespace_flags_ |= CLONE_NEWPID;
// PID namespaces require mount namespaces.
namespace_flags_ |= CLONE_NEWNS;
} else if (args[i] == "mnt") {
namespace_flags_ |= CLONE_NEWNS;
} else {
return Error() << "namespace must be 'pid' or 'mnt'";
}
}
return Success();
}
Result<Success> Service::ParseOomScoreAdjust(const std::vector<std::string>& args) {
if (!ParseInt(args[1], &oom_score_adjust_, -1000, 1000)) {
return Error() << "oom_score_adjust value must be in range -1000 - +1000";
}
return Success();
}
Result<Success> Service::ParseMemcgSwappiness(const std::vector<std::string>& args) {
if (!ParseInt(args[1], &swappiness_, 0)) {
return Error() << "swappiness value must be equal or greater than 0";
}
return Success();
}
Result<Success> Service::ParseMemcgLimitInBytes(const std::vector<std::string>& args) {
if (!ParseInt(args[1], &limit_in_bytes_, 0)) {
return Error() << "limit_in_bytes value must be equal or greater than 0";
}
return Success();
}
Result<Success> Service::ParseMemcgSoftLimitInBytes(const std::vector<std::string>& args) {
if (!ParseInt(args[1], &soft_limit_in_bytes_, 0)) {
return Error() << "soft_limit_in_bytes value must be equal or greater than 0";
}
return Success();
}
Result<Success> Service::ParseProcessRlimit(const std::vector<std::string>& args) {
auto rlimit = ParseRlimit(args);
if (!rlimit) return rlimit.error();
rlimits_.emplace_back(*rlimit);
return Success();
}
Result<Success> Service::ParseSeclabel(const std::vector<std::string>& args) {
seclabel_ = args[1];
return Success();
}
Result<Success> Service::ParseSetenv(const std::vector<std::string>& args) {
environment_vars_.emplace_back(args[1], args[2]);
return Success();
}
Result<Success> Service::ParseShutdown(const std::vector<std::string>& args) {
if (args[1] == "critical") {
flags_ |= SVC_SHUTDOWN_CRITICAL;
return Success();
}
return Error() << "Invalid shutdown option";
}
template <typename T>
Result<Success> Service::AddDescriptor(const std::vector<std::string>& args) {
int perm = args.size() > 3 ? std::strtoul(args[3].c_str(), 0, 8) : -1;
Result<uid_t> uid = 0;
Result<gid_t> gid = 0;
std::string context = args.size() > 6 ? args[6] : "";
if (args.size() > 4) {
uid = DecodeUid(args[4]);
if (!uid) {
return Error() << "Unable to find UID for '" << args[4] << "': " << uid.error();
}
}
if (args.size() > 5) {
gid = DecodeUid(args[5]);
if (!gid) {
return Error() << "Unable to find GID for '" << args[5] << "': " << gid.error();
}
}
auto descriptor = std::make_unique<T>(args[1], args[2], *uid, *gid, perm, context);
auto old =
std::find_if(descriptors_.begin(), descriptors_.end(),
[&descriptor] (const auto& other) { return descriptor.get() == other.get(); });
if (old != descriptors_.end()) {
return Error() << "duplicate descriptor " << args[1] << " " << args[2];
}
descriptors_.emplace_back(std::move(descriptor));
return Success();
}
// name type perm [ uid gid context ]
Result<Success> Service::ParseSocket(const std::vector<std::string>& args) {
if (!StartsWith(args[2], "dgram") && !StartsWith(args[2], "stream") &&
!StartsWith(args[2], "seqpacket")) {
return Error() << "socket type must be 'dgram', 'stream' or 'seqpacket'";
}
return AddDescriptor<SocketInfo>(args);
}
// name type perm [ uid gid context ]
Result<Success> Service::ParseFile(const std::vector<std::string>& args) {
if (args[2] != "r" && args[2] != "w" && args[2] != "rw") {
return Error() << "file type must be 'r', 'w' or 'rw'";
}
if ((args[1][0] != '/') || (args[1].find("../") != std::string::npos)) {
return Error() << "file name must not be relative";
}
return AddDescriptor<FileInfo>(args);
}
Result<Success> Service::ParseUser(const std::vector<std::string>& args) {
auto uid = DecodeUid(args[1]);
if (!uid) {
return Error() << "Unable to find UID for '" << args[1] << "': " << uid.error();
}
uid_ = *uid;
return Success();
}
Result<Success> Service::ParseWritepid(const std::vector<std::string>& args) {
writepid_files_.assign(args.begin() + 1, args.end());
return Success();
}
class Service::OptionParserMap : public KeywordMap<OptionParser> {
public:
OptionParserMap() {}
private:
const Map& map() const override;
};
const Service::OptionParserMap::Map& Service::OptionParserMap::map() const {
constexpr std::size_t kMax = std::numeric_limits<std::size_t>::max();
// clang-format off
static const Map option_parsers = {
{"capabilities",
{1, kMax, &Service::ParseCapabilities}},
{"class", {1, kMax, &Service::ParseClass}},
{"console", {0, 1, &Service::ParseConsole}},
{"critical", {0, 0, &Service::ParseCritical}},
{"disabled", {0, 0, &Service::ParseDisabled}},
{"group", {1, NR_SVC_SUPP_GIDS + 1, &Service::ParseGroup}},
{"ioprio", {2, 2, &Service::ParseIoprio}},
{"priority", {1, 1, &Service::ParsePriority}},
{"keycodes", {1, kMax, &Service::ParseKeycodes}},
{"oneshot", {0, 0, &Service::ParseOneshot}},
{"onrestart", {1, kMax, &Service::ParseOnrestart}},
{"oom_score_adjust",
{1, 1, &Service::ParseOomScoreAdjust}},
{"memcg.swappiness",
{1, 1, &Service::ParseMemcgSwappiness}},
{"memcg.soft_limit_in_bytes",
{1, 1, &Service::ParseMemcgSoftLimitInBytes}},
{"memcg.limit_in_bytes",
{1, 1, &Service::ParseMemcgLimitInBytes}},
{"namespace", {1, 2, &Service::ParseNamespace}},
{"rlimit", {3, 3, &Service::ParseProcessRlimit}},
{"seclabel", {1, 1, &Service::ParseSeclabel}},
{"setenv", {2, 2, &Service::ParseSetenv}},
{"shutdown", {1, 1, &Service::ParseShutdown}},
{"socket", {3, 6, &Service::ParseSocket}},
{"file", {2, 2, &Service::ParseFile}},
{"user", {1, 1, &Service::ParseUser}},
{"writepid", {1, kMax, &Service::ParseWritepid}},
};
// clang-format on
return option_parsers;
}
Result<Success> Service::ParseLine(const std::vector<std::string>& args) {
static const OptionParserMap parser_map;
auto parser = parser_map.FindFunction(args);
if (!parser) return parser.error();
return std::invoke(*parser, this, args);
}
Result<Success> Service::ExecStart() {
flags_ |= SVC_ONESHOT;
if (auto result = Start(); !result) {
return result;
}
flags_ |= SVC_EXEC;
is_exec_service_running_ = true;
LOG(INFO) << "SVC_EXEC pid " << pid_ << " (uid " << uid_ << " gid " << gid_ << "+"
<< supp_gids_.size() << " context " << (!seclabel_.empty() ? seclabel_ : "default")
<< ") started; waiting...";
return Success();
}
Result<Success> Service::Start() {
// 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.
if (flags_ & SVC_RUNNING) {
// It is not an error to try to start a service that is already running.
return Success();
}
bool needs_console = (flags_ & SVC_CONSOLE);
if (needs_console) {
if (console_.empty()) {
console_ = default_console;
}
// Make sure that open call succeeds to ensure a console driver is
// properly registered for the device node
int console_fd = open(console_.c_str(), O_RDWR | O_CLOEXEC);
if (console_fd < 0) {
flags_ |= SVC_DISABLED;
return ErrnoError() << "Couldn't open console '" << 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(name_, args_[0]);
if (!result) {
return result.error();
}
scon = *result;
}
LOG(INFO) << "starting service '" << name_ << "'...";
pid_t pid = -1;
if (namespace_flags_) {
pid = clone(nullptr, nullptr, namespace_flags_ | SIGCHLD, nullptr);
} else {
pid = fork();
}
if (pid == 0) {
umask(077);
if (namespace_flags_ & CLONE_NEWPID) {
// This will fork again to run an init process inside the PID
// namespace.
SetUpPidNamespace(name_);
}
for (const auto& [key, value] : environment_vars_) {
setenv(key.c_str(), value.c_str(), 1);
}
std::for_each(descriptors_.begin(), descriptors_.end(),
std::bind(&DescriptorInfo::CreateAndPublish, std::placeholders::_1, scon));
// See if there were "writepid" instructions to write to files under /dev/cpuset/.
auto cpuset_predicate = [](const std::string& path) {
return StartsWith(path, "/dev/cpuset/");
};
auto iter = std::find_if(writepid_files_.begin(), writepid_files_.end(), cpuset_predicate);
if (iter == writepid_files_.end()) {
// There were no "writepid" instructions for cpusets, check if the system default
// cpuset is specified to be used for the process.
std::string default_cpuset = GetProperty("ro.cpuset.default", "");
if (!default_cpuset.empty()) {
// Make sure the cpuset name starts and ends with '/'.
// A single '/' means the 'root' cpuset.
if (default_cpuset.front() != '/') {
default_cpuset.insert(0, 1, '/');
}
if (default_cpuset.back() != '/') {
default_cpuset.push_back('/');
}
writepid_files_.push_back(
StringPrintf("/dev/cpuset%stasks", default_cpuset.c_str()));
}
}
std::string pid_str = std::to_string(getpid());
for (const auto& file : writepid_files_) {
if (!WriteStringToFile(pid_str, file)) {
PLOG(ERROR) << "couldn't write " << pid_str << " to " << file;
}
}
if (ioprio_class_ != IoSchedClass_NONE) {
if (android_set_ioprio(getpid(), ioprio_class_, ioprio_pri_)) {
PLOG(ERROR) << "failed to set pid " << getpid()
<< " ioprio=" << ioprio_class_ << "," << ioprio_pri_;
}
}
if (needs_console) {
setsid();
OpenConsole();
} else {
ZapStdio();
}
// As requested, set our gid, supplemental gids, uid, context, and
// priority. Aborts on failure.
SetProcessAttributes();
if (!ExpandArgsAndExecv(args_)) {
PLOG(ERROR) << "cannot execve('" << args_[0] << "')";
}
_exit(127);
}
if (pid < 0) {
pid_ = 0;
return ErrnoError() << "Failed to fork";
}
if (oom_score_adjust_ != -1000) {
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: " << strerror(errno);
}
}
time_started_ = boot_clock::now();
pid_ = pid;
flags_ |= SVC_RUNNING;
start_order_ = next_start_order_++;
process_cgroup_empty_ = false;
errno = -createProcessGroup(uid_, pid_);
if (errno != 0) {
PLOG(ERROR) << "createProcessGroup(" << uid_ << ", " << pid_ << ") failed for service '"
<< name_ << "'";
} else {
if (swappiness_ != -1) {
if (!setProcessGroupSwappiness(uid_, pid_, swappiness_)) {
PLOG(ERROR) << "setProcessGroupSwappiness failed";
}
}
if (soft_limit_in_bytes_ != -1) {
if (!setProcessGroupSoftLimit(uid_, pid_, soft_limit_in_bytes_)) {
PLOG(ERROR) << "setProcessGroupSoftLimit failed";
}
}
if (limit_in_bytes_ != -1) {
if (!setProcessGroupLimit(uid_, pid_, limit_in_bytes_)) {
PLOG(ERROR) << "setProcessGroupLimit failed";
}
}
}
NotifyStateChange("running");
return Success();
}
Result<Success> Service::StartIfNotDisabled() {
if (!(flags_ & SVC_DISABLED)) {
return Start();
} else {
flags_ |= SVC_DISABLED_START;
}
return Success();
}
Result<Success> Service::Enable() {
flags_ &= ~(SVC_DISABLED | SVC_RC_DISABLED);
if (flags_ & SVC_DISABLED_START) {
return Start();
}
return Success();
}
void Service::Reset() {
StopOrReset(SVC_RESET);
}
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::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) {
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;
}
if (pid_) {
KillProcessGroup(SIGKILL);
NotifyStateChange("stopping");
} else {
NotifyStateChange("stopped");
}
}
void Service::ZapStdio() const {
int fd;
fd = open("/dev/null", O_RDWR);
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
close(fd);
}
void Service::OpenConsole() const {
int fd = open(console_.c_str(), O_RDWR);
if (fd == -1) fd = open("/dev/null", O_RDWR);
ioctl(fd, TIOCSCTTY, 0);
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
close(fd);
}
ServiceList::ServiceList() {}
ServiceList& ServiceList::GetInstance() {
static ServiceList instance;
return instance;
}
void ServiceList::AddService(std::unique_ptr<Service> service) {
services_.emplace_back(std::move(service));
}
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) {
LOG(ERROR) << "exec called with too many supplementary group ids";
return nullptr;
}
if (command_arg >= args.size()) {
LOG(ERROR) << "exec called without command";
return nullptr;
}
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;
CapSet no_capabilities;
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) {
LOG(ERROR) << "Unable to decode UID for '" << args[2] << "': " << uid.error();
return nullptr;
}
}
Result<gid_t> gid = 0;
std::vector<gid_t> supp_gids;
if (command_arg > 4) {
gid = DecodeUid(args[3]);
if (!gid) {
LOG(ERROR) << "Unable to decode GID for '" << args[3] << "': " << gid.error();
return nullptr;
}
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) {
LOG(ERROR) << "Unable to decode GID for '" << args[4 + i]
<< "': " << supp_gid.error();
return nullptr;
}
supp_gids.push_back(*supp_gid);
}
}
return std::make_unique<Service>(name, flags, *uid, *gid, supp_gids, no_capabilities,
namespace_flags, seclabel, nullptr, str_args);
}
// Shutdown services in the opposite order that they were started.
const std::vector<Service*> ServiceList::services_in_shutdown_order() const {
std::vector<Service*> shutdown_services;
for (const auto& service : services_) {
if (service->start_order() > 0) shutdown_services.emplace_back(service.get());
}
std::sort(shutdown_services.begin(), shutdown_services.end(),
[](const auto& a, const auto& b) { return a->start_order() > b->start_order(); });
return shutdown_services;
}
void ServiceList::RemoveService(const Service& svc) {
auto svc_it = std::find_if(services_.begin(), services_.end(),
[&svc] (const std::unique_ptr<Service>& s) {
return svc.name() == s->name();
});
if (svc_it == services_.end()) {
return;
}
services_.erase(svc_it);
}
void ServiceList::DumpState() const {
for (const auto& s : services_) {
s->DumpState();
}
}
Result<Success> ServiceParser::ParseSection(std::vector<std::string>&& args,
const std::string& filename, int line) {
if (args.size() < 3) {
return Error() << "services must have a name and a program";
}
const std::string& name = args[1];
if (!IsValidName(name)) {
return Error() << "invalid service name '" << name << "'";
}
Service* old_service = service_list_->FindService(name);
if (old_service) {
return Error() << "ignored duplicate definition of service '" << name << "'";
}
Subcontext* restart_action_subcontext = nullptr;
if (subcontexts_) {
for (auto& subcontext : *subcontexts_) {
if (StartsWith(filename, subcontext.path_prefix().c_str())) {
restart_action_subcontext = &subcontext;
break;
}
}
}
std::vector<std::string> str_args(args.begin() + 2, args.end());
service_ = std::make_unique<Service>(name, restart_action_subcontext, str_args);
return Success();
}
Result<Success> ServiceParser::ParseLineSection(std::vector<std::string>&& args, int line) {
return service_ ? service_->ParseLine(std::move(args)) : Success();
}
void ServiceParser::EndSection() {
if (service_) {
service_list_->AddService(std::move(service_));
}
}
bool ServiceParser::IsValidName(const std::string& name) const {
// Property names can be any length, but may only contain certain characters.
// Property values can contain any characters, but may only be a certain length.
// (The latter restriction is needed because `start` and `stop` work by writing
// the service name to the "ctl.start" and "ctl.stop" properties.)
return is_legal_property_name("init.svc." + name) && name.size() <= PROP_VALUE_MAX;
}
} // namespace init
} // namespace android
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