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platform_system_core/init/service.cpp
Tom Cherry 4963b42d7b Merge changes I172acf0f,I97b6e17a 
* changes:
  init: change kill order and fix error reporting in KillProcessGroup()
  Better logging in libprocessgroup and make resources clean up themselves
2017-05-09 17:45:48 +00:00

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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/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 "util.h"
using android::base::boot_clock;
using android::base::ParseInt;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
static 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) {
LOG(ERROR) << "could not get context while starting '" << service_name << "'";
return "";
}
std::unique_ptr<char> mycon(raw_con);
if (getfilecon(service_path.c_str(), &raw_filecon) == -1) {
LOG(ERROR) << "could not get file context while starting '" << service_name << "'";
return "";
}
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()) {
LOG(ERROR) << "service " << service_name << " does not have a SELinux domain defined";
return "";
}
if (rc < 0) {
LOG(ERROR) << "could not get context while starting '" << service_name << "'";
return "";
}
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 void ExpandArgs(const std::vector<std::string>& args, std::vector<char*>* strs) {
std::vector<std::string> expanded_args;
expanded_args.resize(args.size());
strs->push_back(const_cast<char*>(args[0].c_str()));
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] << "'";
}
strs->push_back(const_cast<char*>(expanded_args[i].c_str()));
}
strs->push_back(nullptr);
}
ServiceEnvironmentInfo::ServiceEnvironmentInfo() {
}
ServiceEnvironmentInfo::ServiceEnvironmentInfo(const std::string& name,
const std::string& value)
: name(name), value(value) {
}
Service::Service(const std::string& name, const std::vector<std::string>& args)
: name_(name),
classnames_({"default"}),
flags_(0),
pid_(0),
crash_count_(0),
uid_(0),
gid_(0),
namespace_flags_(0),
seclabel_(""),
onrestart_(false, "<Service '" + name + "' onrestart>", 0),
keychord_id_(0),
ioprio_class_(IoSchedClass_NONE),
ioprio_pri_(0),
priority_(0),
oom_score_adjust_(-1000),
args_(args) {
onrestart_.InitSingleTrigger("onrestart");
}
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,
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, "<Service '" + name + "' onrestart>", 0),
keychord_id_(0),
ioprio_class_(IoSchedClass_NONE),
ioprio_pri_(0),
priority_(0),
oom_score_adjust_(-1000),
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 = StringPrintf("init.svc.%s", name_.c_str());
property_set(prop_name.c_str(), new_state.c_str());
if (new_state == "running") {
uint64_t start_ns = time_started_.time_since_epoch().count();
property_set(StringPrintf("ro.boottime.%s", name_.c_str()).c_str(),
StringPrintf("%" PRIu64, start_ns).c_str());
}
}
void Service::KillProcessGroup(int signal) {
// We ignore reporting errors of ESRCH as this commonly happens in the below case,
// 1) Terminate() is called, which sends SIGTERM to the process
// 2) The process successfully exits
// 3) ReapOneProcess() is called, which calls waitpid(-1, ...) which removes the pid entry.
// 4) Reap() is called, which sends SIGKILL, but the pid no longer exists.
// TODO: sigaction for SIGCHLD reports the pid of the exiting process,
// we should do this kill with that pid first before calling waitpid().
if (kill(-pid_, signal) == -1 && errno != ESRCH) {
PLOG(ERROR) << "kill(" << pid_ << ", " << signal << ") failed";
}
// 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() {
// Keep capabilites on uid change.
if (capabilities_.any() && uid_) {
if (prctl(PR_SET_SECUREBITS, SECBIT_KEEP_CAPS | SECBIT_KEEP_CAPS_LOCKED) != 0) {
PLOG(FATAL) << "prtcl(PR_SET_KEEPCAPS) 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_TEMPORARY) {
return;
}
pid_ = 0;
flags_ &= (~SVC_RUNNING);
// 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(ERROR) << "critical process '" << name_ << "' exited 4 times in 4 minutes";
panic();
}
} 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 '" << android::base::Join(classnames_, " ") << "'";
LOG(INFO) << " exec "<< android::base::Join(args_, " ");
std::for_each(descriptors_.begin(), descriptors_.end(),
[] (const auto& info) { LOG(INFO) << *info; });
}
bool Service::ParseCapabilities(const std::vector<std::string>& args, std::string* err) {
capabilities_ = 0;
if (!CapAmbientSupported()) {
*err = "capabilities requested but the kernel does not support ambient capabilities";
return false;
}
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) {
*err = StringPrintf("invalid capability '%s'", arg.c_str());
return false;
}
unsigned int cap = static_cast<unsigned int>(res); // |res| is >= 0.
if (cap > last_valid_cap) {
*err = StringPrintf("capability '%s' not supported by the kernel", arg.c_str());
return false;
}
capabilities_[cap] = true;
}
return true;
}
bool Service::ParseClass(const std::vector<std::string>& args, std::string* err) {
classnames_ = std::set<std::string>(args.begin() + 1, args.end());
return true;
}
bool Service::ParseConsole(const std::vector<std::string>& args, std::string* err) {
flags_ |= SVC_CONSOLE;
console_ = args.size() > 1 ? "/dev/" + args[1] : "";
return true;
}
bool Service::ParseCritical(const std::vector<std::string>& args, std::string* err) {
flags_ |= SVC_CRITICAL;
return true;
}
bool Service::ParseDisabled(const std::vector<std::string>& args, std::string* err) {
flags_ |= SVC_DISABLED;
flags_ |= SVC_RC_DISABLED;
return true;
}
bool Service::ParseGroup(const std::vector<std::string>& args, std::string* err) {
std::string decode_uid_err;
if (!DecodeUid(args[1], &gid_, &decode_uid_err)) {
*err = "Unable to find GID for '" + args[1] + "': " + decode_uid_err;
return false;
}
for (std::size_t n = 2; n < args.size(); n++) {
gid_t gid;
if (!DecodeUid(args[n], &gid, &decode_uid_err)) {
*err = "Unable to find GID for '" + args[n] + "': " + decode_uid_err;
return false;
}
supp_gids_.emplace_back(gid);
}
return true;
}
bool Service::ParsePriority(const std::vector<std::string>& args, std::string* err) {
priority_ = 0;
if (!ParseInt(args[1], &priority_,
static_cast<int>(ANDROID_PRIORITY_HIGHEST), // highest is negative
static_cast<int>(ANDROID_PRIORITY_LOWEST))) {
*err = StringPrintf("process priority value must be range %d - %d",
ANDROID_PRIORITY_HIGHEST, ANDROID_PRIORITY_LOWEST);
return false;
}
return true;
}
bool Service::ParseIoprio(const std::vector<std::string>& args, std::string* err) {
if (!ParseInt(args[2], &ioprio_pri_, 0, 7)) {
*err = "priority value must be range 0 - 7";
return false;
}
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 {
*err = "ioprio option usage: ioprio <rt|be|idle> <0-7>";
return false;
}
return true;
}
bool Service::ParseKeycodes(const std::vector<std::string>& args, std::string* err) {
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 true;
}
bool Service::ParseOneshot(const std::vector<std::string>& args, std::string* err) {
flags_ |= SVC_ONESHOT;
return true;
}
bool Service::ParseOnrestart(const std::vector<std::string>& args, std::string* err) {
std::vector<std::string> str_args(args.begin() + 1, args.end());
int line = onrestart_.NumCommands() + 1;
onrestart_.AddCommand(str_args, line, err);
return true;
}
bool Service::ParseNamespace(const std::vector<std::string>& args, std::string* err) {
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 {
*err = "namespace must be 'pid' or 'mnt'";
return false;
}
}
return true;
}
bool Service::ParseOomScoreAdjust(const std::vector<std::string>& args, std::string* err) {
if (!ParseInt(args[1], &oom_score_adjust_, -1000, 1000)) {
*err = "oom_score_adjust value must be in range -1000 - +1000";
return false;
}
return true;
}
bool Service::ParseSeclabel(const std::vector<std::string>& args, std::string* err) {
seclabel_ = args[1];
return true;
}
bool Service::ParseSetenv(const std::vector<std::string>& args, std::string* err) {
envvars_.emplace_back(args[1], args[2]);
return true;
}
template <typename T>
bool Service::AddDescriptor(const std::vector<std::string>& args, std::string* err) {
int perm = args.size() > 3 ? std::strtoul(args[3].c_str(), 0, 8) : -1;
uid_t uid = 0;
gid_t gid = 0;
std::string context = args.size() > 6 ? args[6] : "";
std::string decode_uid_err;
if (args.size() > 4) {
if (!DecodeUid(args[4], &uid, &decode_uid_err)) {
*err = "Unable to find UID for '" + args[4] + "': " + decode_uid_err;
return false;
}
}
if (args.size() > 5) {
if (!DecodeUid(args[5], &gid, &decode_uid_err)) {
*err = "Unable to find GID for '" + args[5] + "': " + decode_uid_err;
return false;
}
}
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()) {
*err = "duplicate descriptor " + args[1] + " " + args[2];
return false;
}
descriptors_.emplace_back(std::move(descriptor));
return true;
}
// name type perm [ uid gid context ]
bool Service::ParseSocket(const std::vector<std::string>& args, std::string* err) {
if (!android::base::StartsWith(args[2], "dgram") &&
!android::base::StartsWith(args[2], "stream") &&
!android::base::StartsWith(args[2], "seqpacket")) {
*err = "socket type must be 'dgram', 'stream' or 'seqpacket'";
return false;
}
return AddDescriptor<SocketInfo>(args, err);
}
// name type perm [ uid gid context ]
bool Service::ParseFile(const std::vector<std::string>& args, std::string* err) {
if (args[2] != "r" && args[2] != "w" && args[2] != "rw") {
*err = "file type must be 'r', 'w' or 'rw'";
return false;
}
if ((args[1][0] != '/') || (args[1].find("../") != std::string::npos)) {
*err = "file name must not be relative";
return false;
}
return AddDescriptor<FileInfo>(args, err);
}
bool Service::ParseUser(const std::vector<std::string>& args, std::string* err) {
std::string decode_uid_err;
if (!DecodeUid(args[1], &uid_, &decode_uid_err)) {
*err = "Unable to find UID for '" + args[1] + "': " + decode_uid_err;
return false;
}
return true;
}
bool Service::ParseWritepid(const std::vector<std::string>& args, std::string* err) {
writepid_files_.assign(args.begin() + 1, args.end());
return true;
}
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}},
{"namespace", {1, 2, &Service::ParseNamespace}},
{"seclabel", {1, 1, &Service::ParseSeclabel}},
{"setenv", {2, 2, &Service::ParseSetenv}},
{"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;
}
bool Service::ParseLine(const std::vector<std::string>& args, std::string* err) {
static const OptionParserMap parser_map;
auto parser = parser_map.FindFunction(args, err);
if (!parser) {
return false;
}
return (this->*parser)(args, err);
}
bool Service::ExecStart(std::unique_ptr<Timer>* exec_waiter) {
flags_ |= SVC_EXEC | SVC_ONESHOT;
exec_waiter->reset(new Timer);
if (!Start()) {
exec_waiter->reset();
return false;
}
return true;
}
bool 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) {
return false;
}
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) {
PLOG(ERROR) << "service '" << name_ << "' couldn't open console '" << console_ << "'";
flags_ |= SVC_DISABLED;
return false;
}
close(console_fd);
}
struct stat sb;
if (stat(args_[0].c_str(), &sb) == -1) {
PLOG(ERROR) << "cannot find '" << args_[0] << "', disabling '" << name_ << "'";
flags_ |= SVC_DISABLED;
return false;
}
std::string scon;
if (!seclabel_.empty()) {
scon = seclabel_;
} else {
scon = ComputeContextFromExecutable(name_, args_[0]);
if (scon == "") {
return false;
}
}
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& ei : envvars_) {
add_environment(ei.name.c_str(), ei.value.c_str());
}
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 android::base::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 = android::base::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 = StringPrintf("%d", 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();
std::vector<char*> strs;
ExpandArgs(args_, &strs);
if (execve(strs[0], (char**) &strs[0], (char**) ENV) < 0) {
PLOG(ERROR) << "cannot execve('" << strs[0] << "')";
}
_exit(127);
}
if (pid < 0) {
PLOG(ERROR) << "failed to fork for '" << name_ << "'";
pid_ = 0;
return false;
}
if (oom_score_adjust_ != -1000) {
std::string oom_str = StringPrintf("%d", 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;
process_cgroup_empty_ = false;
errno = -createProcessGroup(uid_, pid_);
if (errno != 0) {
PLOG(ERROR) << "createProcessGroup(" << uid_ << ", " << pid_ << ") failed for service '"
<< name_ << "'";
}
if ((flags_ & SVC_EXEC) != 0) {
LOG(INFO) << android::base::StringPrintf(
"SVC_EXEC pid %d (uid %d gid %d+%zu context %s) started; waiting...", pid_, uid_, gid_,
supp_gids_.size(), !seclabel_.empty() ? seclabel_.c_str() : "default");
}
NotifyStateChange("running");
return true;
}
bool Service::StartIfNotDisabled() {
if (!(flags_ & SVC_DISABLED)) {
return Start();
} else {
flags_ |= SVC_DISABLED_START;
}
return true;
}
bool Service::Enable() {
flags_ &= ~(SVC_DISABLED | SVC_RC_DISABLED);
if (flags_ & SVC_DISABLED_START) {
return Start();
}
return true;
}
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. */
Start();
} /* else: Service is restarting anyways. */
}
void Service::RestartIfNeeded(time_t* process_needs_restart_at) {
boot_clock::time_point now = boot_clock::now();
boot_clock::time_point next_start = time_started_ + 5s;
if (now > next_start) {
flags_ &= (~SVC_RESTARTING);
Start();
return;
}
time_t next_start_time_t = time(nullptr) +
time_t(std::chrono::duration_cast<std::chrono::seconds>(next_start - now).count());
if (next_start_time_t < *process_needs_restart_at || *process_needs_restart_at == 0) {
*process_needs_restart_at = next_start_time_t;
}
}
// 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);
}
int ServiceManager::exec_count_ = 0;
ServiceManager::ServiceManager() {
}
ServiceManager& ServiceManager::GetInstance() {
static ServiceManager instance;
return instance;
}
void ServiceManager::AddService(std::unique_ptr<Service> service) {
services_.emplace_back(std::move(service));
}
bool ServiceManager::Exec(const std::vector<std::string>& args) {
Service* svc = MakeExecOneshotService(args);
if (!svc) {
LOG(ERROR) << "Could not create exec service";
return false;
}
if (!svc->ExecStart(&exec_waiter_)) {
LOG(ERROR) << "Could not start exec service";
ServiceManager::GetInstance().RemoveService(*svc);
return false;
}
return true;
}
bool ServiceManager::ExecStart(const std::string& name) {
Service* svc = FindServiceByName(name);
if (!svc) {
LOG(ERROR) << "ExecStart(" << name << "): Service not found";
return false;
}
if (!svc->ExecStart(&exec_waiter_)) {
LOG(ERROR) << "ExecStart(" << name << "): Could not start Service";
return false;
}
return true;
}
bool ServiceManager::IsWaitingForExec() const { return exec_waiter_ != nullptr; }
Service* ServiceManager::MakeExecOneshotService(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());
exec_count_++;
std::string name =
"exec " + std::to_string(exec_count_) + " (" + android::base::Join(str_args, " ") + ")";
unsigned flags = SVC_EXEC | SVC_ONESHOT | SVC_TEMPORARY;
CapSet no_capabilities;
unsigned namespace_flags = 0;
std::string seclabel = "";
if (command_arg > 2 && args[1] != "-") {
seclabel = args[1];
}
uid_t uid = 0;
if (command_arg > 3) {
std::string decode_uid_err;
if (!DecodeUid(args[2], &uid, &decode_uid_err)) {
LOG(ERROR) << "Unable to find UID for '" << args[2] << "': " << decode_uid_err;
return nullptr;
}
}
gid_t gid = 0;
std::vector<gid_t> supp_gids;
if (command_arg > 4) {
std::string decode_uid_err;
if (!DecodeUid(args[3], &gid, &decode_uid_err)) {
LOG(ERROR) << "Unable to find GID for '" << args[3] << "': " << decode_uid_err;
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) {
gid_t supp_gid;
if (!DecodeUid(args[4 + i], &supp_gid, &decode_uid_err)) {
LOG(ERROR) << "Unable to find UID for '" << args[4 + i] << "': " << decode_uid_err;
return nullptr;
}
supp_gids.push_back(supp_gid);
}
}
auto svc_p = std::make_unique<Service>(name, flags, uid, gid, supp_gids, no_capabilities,
namespace_flags, seclabel, str_args);
Service* svc = svc_p.get();
services_.emplace_back(std::move(svc_p));
return svc;
}
Service* ServiceManager::FindServiceByName(const std::string& name) const {
auto svc = std::find_if(services_.begin(), services_.end(),
[&name] (const std::unique_ptr<Service>& s) {
return name == s->name();
});
if (svc != services_.end()) {
return svc->get();
}
return nullptr;
}
Service* ServiceManager::FindServiceByPid(pid_t pid) const {
auto svc = std::find_if(services_.begin(), services_.end(),
[&pid] (const std::unique_ptr<Service>& s) {
return s->pid() == pid;
});
if (svc != services_.end()) {
return svc->get();
}
return nullptr;
}
Service* ServiceManager::FindServiceByKeychord(int keychord_id) const {
auto svc = std::find_if(services_.begin(), services_.end(),
[&keychord_id] (const std::unique_ptr<Service>& s) {
return s->keychord_id() == keychord_id;
});
if (svc != services_.end()) {
return svc->get();
}
return nullptr;
}
void ServiceManager::ForEachService(const std::function<void(Service*)>& callback) const {
for (const auto& s : services_) {
callback(s.get());
}
}
void ServiceManager::ForEachServiceInClass(const std::string& classname,
void (*func)(Service* svc)) const {
for (const auto& s : services_) {
if (s->classnames().find(classname) != s->classnames().end()) {
func(s.get());
}
}
}
void ServiceManager::ForEachServiceWithFlags(unsigned matchflags,
void (*func)(Service* svc)) const {
for (const auto& s : services_) {
if (s->flags() & matchflags) {
func(s.get());
}
}
}
void ServiceManager::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 ServiceManager::DumpState() const {
for (const auto& s : services_) {
s->DumpState();
}
}
bool ServiceManager::ReapOneProcess() {
int status;
pid_t pid = TEMP_FAILURE_RETRY(waitpid(-1, &status, WNOHANG));
if (pid == 0) {
return false;
} else if (pid == -1) {
PLOG(ERROR) << "waitpid failed";
return false;
}
Service* svc = FindServiceByPid(pid);
std::string name;
std::string wait_string;
if (svc) {
name = android::base::StringPrintf("Service '%s' (pid %d)",
svc->name().c_str(), pid);
if (svc->flags() & SVC_EXEC) {
wait_string =
android::base::StringPrintf(" waiting took %f seconds", exec_waiter_->duration_s());
}
} else {
name = android::base::StringPrintf("Untracked pid %d", pid);
}
if (WIFEXITED(status)) {
LOG(INFO) << name << " exited with status " << WEXITSTATUS(status) << wait_string;
} else if (WIFSIGNALED(status)) {
LOG(INFO) << name << " killed by signal " << WTERMSIG(status) << wait_string;
} else if (WIFSTOPPED(status)) {
LOG(INFO) << name << " stopped by signal " << WSTOPSIG(status) << wait_string;
} else {
LOG(INFO) << name << " state changed" << wait_string;
}
if (!svc) {
return true;
}
svc->Reap();
if (svc->flags() & SVC_EXEC) {
exec_waiter_.reset();
}
if (svc->flags() & SVC_TEMPORARY) {
RemoveService(*svc);
}
return true;
}
void ServiceManager::ReapAnyOutstandingChildren() {
while (ReapOneProcess()) {
}
}
bool ServiceParser::ParseSection(std::vector<std::string>&& args, const std::string& filename,
int line, std::string* err) {
if (args.size() < 3) {
*err = "services must have a name and a program";
return false;
}
const std::string& name = args[1];
if (!IsValidName(name)) {
*err = StringPrintf("invalid service name '%s'", name.c_str());
return false;
}
Service* old_service = service_manager_->FindServiceByName(name);
if (old_service) {
*err = "ignored duplicate definition of service '" + name + "'";
return false;
}
std::vector<std::string> str_args(args.begin() + 2, args.end());
service_ = std::make_unique<Service>(name, str_args);
return true;
}
bool ServiceParser::ParseLineSection(std::vector<std::string>&& args, int line, std::string* err) {
return service_ ? service_->ParseLine(std::move(args), err) : false;
}
void ServiceParser::EndSection() {
if (service_) {
service_manager_->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;
}
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