init: add exec_start command
Exec services may also want to set other service flags such as
priority. Instead of expanding the exec syntax to handle this, create
a new command, exec_start, that will treat an existing service
definition as an exec service. The new exec_start command will start
the service then halt init from executing further commands until the
service has exited.
This change additionally encapsulates the waiting_for_exec logic into
ServiceManager and removes the ambiguous 'bool' return value from
Reap() which previously indicated if a Reaped service was an exec
service or not.
Bug: 36511808
Bug: 36102163
Test: Bullhead boots, services run with exec_start as they do exec.
Change-Id: I44f775cf1c1dd81d5c715f44fdc150c651a2c80a
(cherry picked from commit b27004aa05039b5196f1e878169dca41b68aadd6)
diff --git a/init/README.md b/init/README.md
index 024d559..0d8f495 100644
--- a/init/README.md
+++ b/init/README.md
@@ -311,6 +311,12 @@
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 <service>`
+> 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 <name> <value>`
> Set the environment variable _name_ equal to _value_ in the
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 95f1aa0..db42aa3 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -167,19 +167,11 @@
}
static int do_exec(const std::vector<std::string>& 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<std::string>& args) {
+ return ServiceManager::GetInstance().ExecStart(args[1]) ? 0 : -1;
}
static int do_export(const std::vector<std::string>& args) {
@@ -898,6 +890,7 @@
BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
constexpr std::size_t kMax = std::numeric_limits<std::size_t>::max();
+ // clang-format off
static const Map builtin_functions = {
{"bootchart", {1, 1, do_bootchart}},
{"chmod", {2, 2, do_chmod}},
@@ -910,6 +903,7 @@
{"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}},
@@ -943,5 +937,6 @@
{"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 23448d6..5447007 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -86,8 +86,6 @@
const char *ENV[32];
-static std::unique_ptr<Timer> waiting_for_exec(nullptr);
-
static int epoll_fd = -1;
static std::unique_ptr<Timer> waiting_for_prop(nullptr);
@@ -135,23 +133,6 @@
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) {
@@ -1325,10 +1306,10 @@
// 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 b4d25fb..fe850ef 100644
--- a/init/init.h
+++ b/init/init.h
@@ -32,10 +32,6 @@
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 c6ef838..0bc42ef 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -191,8 +191,8 @@
}
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;
}
@@ -259,7 +259,7 @@
}
}
-bool Service::Reap() {
+void Service::Reap() {
if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) {
KillProcessGroup(SIGKILL);
}
@@ -270,7 +270,10 @@
if (flags_ & SVC_EXEC) {
LOG(INFO) << "SVC_EXEC pid " << pid_ << " finished...";
- return true;
+ }
+
+ if (flags_ & SVC_TEMPORARY) {
+ return;
}
pid_ = 0;
@@ -285,7 +288,7 @@
// 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.
@@ -309,7 +312,7 @@
onrestart_.ExecuteAllCommands();
NotifyStateChange("restarting");
- return false;
+ return;
}
void Service::DumpState() const {
@@ -577,6 +580,18 @@
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.
@@ -863,6 +878,35 @@
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
@@ -886,7 +930,7 @@
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;
@@ -1026,8 +1070,13 @@
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 9a9046b..f08a03f 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 @@
bool IsRunning() { return (flags_ & SVC_RUNNING) != 0; }
bool ParseLine(const std::vector<std::string>& args, std::string* err);
+ bool ExecStart(std::unique_ptr<Timer>* exec_waiter);
bool Start();
bool StartIfNotDisabled();
bool Enable();
@@ -80,7 +84,7 @@
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 @@
void AddService(std::unique_ptr<Service> service);
Service* MakeExecOneshotService(const std::vector<std::string>& args);
+ bool Exec(const std::vector<std::string>& 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 @@
bool ReapOneProcess();
static int exec_count_; // Every service needs a unique name.
+ std::unique_ptr<Timer> exec_waiter_;
+
std::vector<std::unique_ptr<Service>> services_;
};