diff --git a/init/README.md b/init/README.md index 024d5591b..0d8f4954c 100644 --- a/init/README.md +++ b/init/README.md @@ -311,6 +311,12 @@ Commands groups can be provided. No other commands will be run until this one finishes. _seclabel_ can be a - to denote default. Properties are expanded within _argument_. + Init halts executing commands until the forked process exits. + +`exec_start ` +> Start service a given service and halt processing of additional init commands + until it returns. It functions similarly to the `exec` command, but uses an + existing service definition instead of providing them as arguments. `export ` > Set the environment variable _name_ equal to _value_ in the diff --git a/init/builtins.cpp b/init/builtins.cpp index 5a67e5e1e..02e314f64 100644 --- a/init/builtins.cpp +++ b/init/builtins.cpp @@ -167,19 +167,11 @@ static int do_enable(const std::vector& args) { } static int do_exec(const std::vector& args) { - Service* svc = ServiceManager::GetInstance().MakeExecOneshotService(args); - if (!svc) { - return -1; - } - if (!start_waiting_for_exec()) { - return -1; - } - if (!svc->Start()) { - stop_waiting_for_exec(); - ServiceManager::GetInstance().RemoveService(*svc); - return -1; - } - return 0; + return ServiceManager::GetInstance().Exec(args) ? 0 : -1; +} + +static int do_exec_start(const std::vector& args) { + return ServiceManager::GetInstance().ExecStart(args[1]) ? 0 : -1; } static int do_export(const std::vector& args) { @@ -897,6 +889,7 @@ static int do_init_user0(const std::vector& args) { BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const { constexpr std::size_t kMax = std::numeric_limits::max(); + // clang-format off static const Map builtin_functions = { {"bootchart", {1, 1, do_bootchart}}, {"chmod", {2, 2, do_chmod}}, @@ -909,6 +902,7 @@ BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const { {"domainname", {1, 1, do_domainname}}, {"enable", {1, 1, do_enable}}, {"exec", {1, kMax, do_exec}}, + {"exec_start", {1, 1, do_exec_start}}, {"export", {2, 2, do_export}}, {"hostname", {1, 1, do_hostname}}, {"ifup", {1, 1, do_ifup}}, @@ -942,5 +936,6 @@ BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const { {"wait_for_prop", {2, 2, do_wait_for_prop}}, {"write", {2, 2, do_write}}, }; + // clang-format on return builtin_functions; } diff --git a/init/init.cpp b/init/init.cpp index 6f76233b4..4249115b2 100644 --- a/init/init.cpp +++ b/init/init.cpp @@ -84,8 +84,6 @@ static time_t process_needs_restart_at; const char *ENV[32]; -static std::unique_ptr waiting_for_exec(nullptr); - static int epoll_fd = -1; static std::unique_ptr waiting_for_prop(nullptr); @@ -133,23 +131,6 @@ int add_environment(const char *key, const char *val) return -1; } -bool start_waiting_for_exec() -{ - if (waiting_for_exec) { - return false; - } - waiting_for_exec.reset(new Timer()); - return true; -} - -void stop_waiting_for_exec() -{ - if (waiting_for_exec) { - LOG(INFO) << "Wait for exec took " << *waiting_for_exec; - waiting_for_exec.reset(); - } -} - bool start_waiting_for_property(const char *name, const char *value) { if (waiting_for_prop) { @@ -1323,10 +1304,10 @@ int main(int argc, char** argv) { // By default, sleep until something happens. int epoll_timeout_ms = -1; - if (!(waiting_for_exec || waiting_for_prop)) { + if (!(waiting_for_prop || ServiceManager::GetInstance().IsWaitingForExec())) { am.ExecuteOneCommand(); } - if (!(waiting_for_exec || waiting_for_prop)) { + if (!(waiting_for_prop || ServiceManager::GetInstance().IsWaitingForExec())) { restart_processes(); // If there's a process that needs restarting, wake up in time for that. diff --git a/init/init.h b/init/init.h index b4d25fb0b..fe850efd7 100644 --- a/init/init.h +++ b/init/init.h @@ -32,10 +32,6 @@ void register_epoll_handler(int fd, void (*fn)()); int add_environment(const char* key, const char* val); -bool start_waiting_for_exec(); - -void stop_waiting_for_exec(); - bool start_waiting_for_property(const char *name, const char *value); #endif /* _INIT_INIT_H */ diff --git a/init/service.cpp b/init/service.cpp index 99fc9a919..ede63640d 100644 --- a/init/service.cpp +++ b/init/service.cpp @@ -192,8 +192,8 @@ Service::Service(const std::string& name, unsigned flags, uid_t uid, gid_t gid, } void Service::NotifyStateChange(const std::string& new_state) const { - if ((flags_ & SVC_EXEC) != 0) { - // 'exec' commands don't have properties tracking their state. + if ((flags_ & SVC_TEMPORARY) != 0) { + // Services created by 'exec' are temporary and don't have properties tracking their state. return; } @@ -260,7 +260,7 @@ void Service::SetProcessAttributes() { } } -bool Service::Reap() { +void Service::Reap() { if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) { KillProcessGroup(SIGKILL); } @@ -271,7 +271,10 @@ bool Service::Reap() { if (flags_ & SVC_EXEC) { LOG(INFO) << "SVC_EXEC pid " << pid_ << " finished..."; - return true; + } + + if (flags_ & SVC_TEMPORARY) { + return; } pid_ = 0; @@ -286,7 +289,7 @@ bool Service::Reap() { // Disabled and reset processes do not get restarted automatically. if (flags_ & (SVC_DISABLED | SVC_RESET)) { NotifyStateChange("stopped"); - return false; + return; } // If we crash > 4 times in 4 minutes, reboot into recovery. @@ -310,7 +313,7 @@ bool Service::Reap() { onrestart_.ExecuteAllCommands(); NotifyStateChange("restarting"); - return false; + return; } void Service::DumpState() const { @@ -578,6 +581,18 @@ bool Service::ParseLine(const std::vector& args, std::string* err) return (this->*parser)(args, err); } +bool Service::ExecStart(std::unique_ptr* 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. @@ -864,6 +879,35 @@ void ServiceManager::AddService(std::unique_ptr service) { services_.emplace_back(std::move(service)); } +bool ServiceManager::Exec(const std::vector& 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& args) { // Parse the arguments: exec [SECLABEL [UID [GID]*] --] COMMAND ARGS... // SECLABEL can be a - to denote default @@ -887,7 +931,7 @@ Service* ServiceManager::MakeExecOneshotService(const std::vector& exec_count_++; std::string name = StringPrintf("exec %d (%s)", exec_count_, str_args[0].c_str()); - unsigned flags = SVC_EXEC | SVC_ONESHOT; + unsigned flags = SVC_EXEC | SVC_ONESHOT | SVC_TEMPORARY; CapSet no_capabilities; unsigned namespace_flags = 0; @@ -1027,8 +1071,13 @@ bool ServiceManager::ReapOneProcess() { return true; } - if (svc->Reap()) { - stop_waiting_for_exec(); + svc->Reap(); + + if (svc->flags() & SVC_EXEC) { + LOG(INFO) << "Wait for exec took " << *exec_waiter_; + exec_waiter_.reset(); + } + if (svc->flags() & SVC_TEMPORARY) { RemoveService(*svc); } diff --git a/init/service.h b/init/service.h index 9a9046b9e..f08a03f9a 100644 --- a/init/service.h +++ b/init/service.h @@ -44,10 +44,13 @@ #define SVC_RC_DISABLED 0x080 // Remember if the disabled flag was set in the rc script. #define SVC_RESTART 0x100 // Use to safely restart (stop, wait, start) a service. #define SVC_DISABLED_START 0x200 // A start was requested but it was disabled at the time. -#define SVC_EXEC 0x400 // This synthetic service corresponds to an 'exec'. +#define SVC_EXEC 0x400 // This service was started by either 'exec' or 'exec_start' and stops + // init from processing more commands until it completes #define SVC_SHUTDOWN_CRITICAL 0x800 // This service is critical for shutdown and // should not be killed during shutdown +#define SVC_TEMPORARY 0x1000 // This service was started by 'exec' and should be removed from the + // service list once it is reaped. #define NR_SVC_SUPP_GIDS 12 // twelve supplementary groups @@ -72,6 +75,7 @@ class Service { bool IsRunning() { return (flags_ & SVC_RUNNING) != 0; } bool ParseLine(const std::vector& args, std::string* err); + bool ExecStart(std::unique_ptr* exec_waiter); bool Start(); bool StartIfNotDisabled(); bool Enable(); @@ -80,7 +84,7 @@ class Service { void Terminate(); void Restart(); void RestartIfNeeded(time_t* process_needs_restart_at); - bool Reap(); + void Reap(); void DumpState() const; void SetShutdownCritical() { flags_ |= SVC_SHUTDOWN_CRITICAL; } bool IsShutdownCritical() const { return (flags_ & SVC_SHUTDOWN_CRITICAL) != 0; } @@ -178,6 +182,9 @@ public: void AddService(std::unique_ptr service); Service* MakeExecOneshotService(const std::vector& args); + bool Exec(const std::vector& args); + bool ExecStart(const std::string& name); + bool IsWaitingForExec() const; Service* FindServiceByName(const std::string& name) const; Service* FindServiceByPid(pid_t pid) const; Service* FindServiceByKeychord(int keychord_id) const; @@ -198,6 +205,8 @@ private: bool ReapOneProcess(); static int exec_count_; // Every service needs a unique name. + std::unique_ptr exec_waiter_; + std::vector> services_; };