dumpsys: add --pid option

We can't change the output format of dumpsys since too many places rely
on it, so introducing a separate option to dump the PID of a service.

Fixes: 141187318
Test: dumpsys_test, bugreport, also:
$ adb shell dumpsys --pid
...
-------------------------------------------------------------------------------
DUMP OF SERVICE package_native:
1165
--------- 0.001s was the duration of dumpsys package_native, ending at: 2019-10-08 20:35:32
...
(dumps pids of all services)

or with specific service name only:
$ dumpsys --pid package_native
1165

Change-Id: Iaa2478568245ca7d10d2e3f8ebafe43d2d26df2c

4 files changed, 68 insertions, 13 deletions

diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index 739f9ca8e3..67f12e8efe 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -1082,7 +1082,7 @@ static Dumpstate::RunStatus RunDumpsysTextByPriority(const std::string& title, i
         std::string path(title);
         path.append(" - ").append(String8(service).c_str());
         size_t bytes_written = 0;
-        status_t status = dumpsys.startDumpThread(service, args);
+        status_t status = dumpsys.startDumpThread(Dumpsys::Type::DUMP, service, args);
         if (status == OK) {
             dumpsys.writeDumpHeader(STDOUT_FILENO, service, priority);
             std::chrono::duration<double> elapsed_seconds;
@@ -1154,7 +1154,7 @@ static Dumpstate::RunStatus RunDumpsysProto(const std::string& title, int priori
             path.append("_HIGH");
         }
         path.append(kProtoExt);
-        status_t status = dumpsys.startDumpThread(service, args);
+        status_t status = dumpsys.startDumpThread(Dumpsys::Type::DUMP, service, args);
         if (status == OK) {
             status = ds.AddZipEntryFromFd(path, dumpsys.getDumpFd(), service_timeout);
             bool dumpTerminated = (status == OK);
diff --git a/cmds/dumpsys/dumpsys.cpp b/cmds/dumpsys/dumpsys.cpp
index 232dcec166..abdf168233 100644
--- a/cmds/dumpsys/dumpsys.cpp
+++ b/cmds/dumpsys/dumpsys.cpp
@@ -59,12 +59,13 @@ static void usage() {
             "usage: dumpsys\n"
             "         To dump all services.\n"
             "or:\n"
-            "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--help | -l | --skip SERVICES | "
-            "SERVICE [ARGS]]\n"
+            "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--pid] [--help | -l | --skip SERVICES "
+            "| SERVICE [ARGS]]\n"
             "         --help: shows this help\n"
             "         -l: only list services, do not dump them\n"
             "         -t TIMEOUT_SEC: TIMEOUT to use in seconds instead of default 10 seconds\n"
             "         -T TIMEOUT_MS: TIMEOUT to use in milliseconds instead of default 10 seconds\n"
+            "         --pid: dump PID instead of usual dump\n"
             "         --proto: filter services that support dumping data in proto format. Dumps\n"
             "               will be in proto format.\n"
             "         --priority LEVEL: filter services based on specified priority\n"
@@ -120,9 +121,11 @@ int Dumpsys::main(int argc, char* const argv[]) {
     bool showListOnly = false;
     bool skipServices = false;
     bool asProto = false;
+    Type type = Type::DUMP;
     int timeoutArgMs = 10000;
     int priorityFlags = IServiceManager::DUMP_FLAG_PRIORITY_ALL;
-    static struct option longOptions[] = {{"priority", required_argument, 0, 0},
+    static struct option longOptions[] = {{"pid", no_argument, 0, 0},
+                                          {"priority", required_argument, 0, 0},
                                           {"proto", no_argument, 0, 0},
                                           {"skip", no_argument, 0, 0},
                                           {"help", no_argument, 0, 0},
@@ -157,6 +160,8 @@ int Dumpsys::main(int argc, char* const argv[]) {
                     usage();
                     return -1;
                 }
+            } else if (!strcmp(longOptions[optionIndex].name, "pid")) {
+                type = Type::PID;
             }
             break;
 
@@ -246,7 +251,7 @@ int Dumpsys::main(int argc, char* const argv[]) {
         const String16& serviceName = services[i];
         if (IsSkipped(skippedServices, serviceName)) continue;
 
-        if (startDumpThread(serviceName, args) == OK) {
+        if (startDumpThread(type, serviceName, args) == OK) {
             bool addSeparator = (N > 1);
             if (addSeparator) {
                 writeDumpHeader(STDOUT_FILENO, serviceName, priorityFlags);
@@ -313,7 +318,18 @@ void Dumpsys::setServiceArgs(Vector<String16>& args, bool asProto, int priorityF
     }
 }
 
-status_t Dumpsys::startDumpThread(const String16& serviceName, const Vector<String16>& args) {
+static status_t dumpPidToFd(const sp<IBinder>& service, const unique_fd& fd) {
+     pid_t pid;
+     status_t status = service->getDebugPid(&pid);
+     if (status != OK) {
+         return status;
+     }
+     WriteStringToFd(std::to_string(pid) + "\n", fd.get());
+     return OK;
+}
+
+status_t Dumpsys::startDumpThread(Type type, const String16& serviceName,
+                                  const Vector<String16>& args) {
     sp<IBinder> service = sm_->checkService(serviceName);
     if (service == nullptr) {
         aerr << "Can't find service: " << serviceName << endl;
@@ -333,10 +349,22 @@ status_t Dumpsys::startDumpThread(const String16& serviceName, const Vector<Stri
 
     // dump blocks until completion, so spawn a thread..
     activeThread_ = std::thread([=, remote_end{std::move(remote_end)}]() mutable {
-        int err = service->dump(remote_end.get(), args);
+        status_t err = 0;
+
+        switch (type) {
+        case Type::DUMP:
+            err = service->dump(remote_end.get(), args);
+            break;
+        case Type::PID:
+            err = dumpPidToFd(service, remote_end);
+            break;
+        default:
+            aerr << "Unknown dump type" << static_cast<int>(type) << endl;
+            return;
+        }
 
-        if (err != 0) {
-            aerr << "Error dumping service info: (" << strerror(err) << ") "
+        if (err != OK) {
+            aerr << "Error dumping service info status_t: (" << err << ") "
                  << serviceName << endl;
         }
     });
diff --git a/cmds/dumpsys/dumpsys.h b/cmds/dumpsys/dumpsys.h
index c48a1e959b..929c55c364 100644
--- a/cmds/dumpsys/dumpsys.h
+++ b/cmds/dumpsys/dumpsys.h
@@ -51,6 +51,11 @@ class Dumpsys {
      */
     static void setServiceArgs(Vector<String16>& args, bool asProto, int priorityFlags);
 
+    enum class Type {
+        DUMP,  // dump using `dump` function
+        PID,   // dump pid of server only
+    };
+
     /**
      * Starts a thread to connect to a service and get its dump output. The thread redirects
      * the output to a pipe. Thread must be stopped by a subsequent callto {@code
@@ -61,7 +66,8 @@ class Dumpsys {
      *         {@code NAME_NOT_FOUND} service could not be found.
      *         {@code != OK} error
      */
-    status_t startDumpThread(const String16& serviceName, const Vector<String16>& args);
+    status_t startDumpThread(Type type, const String16& serviceName,
+                             const Vector<String16>& args);
 
     /**
      * Writes a section header to a file descriptor.
diff --git a/cmds/dumpsys/tests/dumpsys_test.cpp b/cmds/dumpsys/tests/dumpsys_test.cpp
index cbac839e6f..cf4e0b5a4c 100644
--- a/cmds/dumpsys/tests/dumpsys_test.cpp
+++ b/cmds/dumpsys/tests/dumpsys_test.cpp
@@ -194,7 +194,7 @@ class DumpsysTest : public Test {
         CaptureStdout();
         CaptureStderr();
         dump_.setServiceArgs(args, supportsProto, priorityFlags);
-        status_t status = dump_.startDumpThread(serviceName, args);
+        status_t status = dump_.startDumpThread(Dumpsys::Type::DUMP, serviceName, args);
         EXPECT_THAT(status, Eq(0));
         status = dump_.writeDump(STDOUT_FILENO, serviceName, std::chrono::milliseconds(500), false,
                                  elapsedDuration, bytesWritten);
@@ -539,6 +539,27 @@ TEST_F(DumpsysTest, DumpWithPriorityHighAndProto) {
     AssertDumpedWithPriority("runninghigh2", "dump2", PriorityDumper::PRIORITY_ARG_HIGH);
 }
 
+// Tests 'dumpsys --pid'
+TEST_F(DumpsysTest, ListAllServicesWithPid) {
+    ExpectListServices({"Locksmith", "Valet"});
+    ExpectCheckService("Locksmith");
+    ExpectCheckService("Valet");
+
+    CallMain({"--pid"});
+
+    AssertRunningServices({"Locksmith", "Valet"});
+    AssertOutputContains(std::to_string(getpid()));
+}
+
+// Tests 'dumpsys --pid service_name'
+TEST_F(DumpsysTest, ListServiceWithPid) {
+    ExpectCheckService("Locksmith");
+
+    CallMain({"--pid", "Locksmith"});
+
+    AssertOutput(std::to_string(getpid()) + "\n");
+}
+
 TEST_F(DumpsysTest, GetBytesWritten) {
     const char* serviceName = "service2";
     const char* dumpContents = "dump1";
@@ -563,4 +584,4 @@ TEST_F(DumpsysTest, WriteDumpWithoutThreadStart) {
         dump_.writeDump(STDOUT_FILENO, String16("service"), std::chrono::milliseconds(500),
                         /* as_proto = */ false, elapsedDuration, bytesWritten);
     EXPECT_THAT(status, Eq(INVALID_OPERATION));
-}
\ No newline at end of file
+}