dumpsys: display the client PIDs of all of the services

When gathering info on a service, get the BpBinder handle to look up the
node number of the binder service in binder_logs/proc/<pid>.
Look up the node number in binder_logs/state from the binder service.
That entry in the state file has the client PIDs.

Example output:
$ adb shell dumpsys --clients android.hardware.power.IPower/default
Client PIDs: 437, 708, 203

Test: adb root && adb shell dumpsys --clients
Test: adb shell dumpsys --clients power
Test: adb shell dumpsys --clients --pid
Change-Id: I0daebc18cb9f47925ccec5a3eb0b09c4b1e43fe4

5 files changed, 160 insertions, 34 deletions

diff --git a/cmds/dumpsys/dumpsys.cpp b/cmds/dumpsys/dumpsys.cpp
index f8fdaa094e..3d2bdf1d6f 100644
--- a/cmds/dumpsys/dumpsys.cpp
+++ b/cmds/dumpsys/dumpsys.cpp
@@ -21,7 +21,9 @@
 
 #include <android-base/file.h>
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
+#include <binder/BpBinder.h>
 #include <binder/Parcel.h>
 #include <binder/ProcessState.h>
 #include <binder/Stability.h>
@@ -58,27 +60,30 @@ static int sort_func(const String16* lhs, const String16* rhs)
 }
 
 static void usage() {
-    fprintf(stderr,
-            "usage: dumpsys\n"
-            "         To dump all services.\n"
-            "or:\n"
-            "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--dump] [--pid] [--thread] [--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"
-            "         --dump: ask the service to dump itself (this is the default)\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"
-            "               LEVEL must be one of CRITICAL | HIGH | NORMAL\n"
-            "         --skip SERVICES: dumps all services but SERVICES (comma-separated list)\n"
-            "         --stability: dump binder stability information instead of usual dump\n"
-            "         --thread: dump thread usage instead of usual dump\n"
-            "         SERVICE [ARGS]: dumps only service SERVICE, optionally passing ARGS to it\n");
+    fprintf(
+        stderr,
+        "usage: dumpsys\n"
+        "         To dump all services.\n"
+        "or:\n"
+        "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--clients] [--dump] [--pid] [--thread] "
+        "[--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"
+        "         --clients: dump client PIDs instead of usual dump\n"
+        "         --dump: ask the service to dump itself (this is the default)\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"
+        "               LEVEL must be one of CRITICAL | HIGH | NORMAL\n"
+        "         --skip SERVICES: dumps all services but SERVICES (comma-separated list)\n"
+        "         --stability: dump binder stability information instead of usual dump\n"
+        "         --thread: dump thread usage instead of usual dump\n"
+        "         SERVICE [ARGS]: dumps only service SERVICE, optionally passing ARGS to it\n");
 }
 
 static bool IsSkipped(const Vector<String16>& skipped, const String16& service) {
@@ -131,15 +136,12 @@ int Dumpsys::main(int argc, char* const argv[]) {
     int dumpTypeFlags = 0;
     int timeoutArgMs = 10000;
     int priorityFlags = IServiceManager::DUMP_FLAG_PRIORITY_ALL;
-    static struct option longOptions[] = {{"help", no_argument, 0, 0},
-                                          {"dump", no_argument, 0, 0},
-                                          {"pid", no_argument, 0, 0},
-                                          {"priority", required_argument, 0, 0},
-                                          {"proto", no_argument, 0, 0},
-                                          {"skip", no_argument, 0, 0},
-                                          {"stability", no_argument, 0, 0},
-                                          {"thread", no_argument, 0, 0},
-                                          {0, 0, 0, 0}};
+    static struct option longOptions[] = {
+        {"help", no_argument, 0, 0},           {"clients", no_argument, 0, 0},
+        {"dump", no_argument, 0, 0},           {"pid", no_argument, 0, 0},
+        {"priority", required_argument, 0, 0}, {"proto", no_argument, 0, 0},
+        {"skip", no_argument, 0, 0},           {"stability", no_argument, 0, 0},
+        {"thread", no_argument, 0, 0},         {0, 0, 0, 0}};
 
     // Must reset optind, otherwise subsequent calls will fail (wouldn't happen on main.cpp, but
     // happens on test cases).
@@ -178,6 +180,8 @@ int Dumpsys::main(int argc, char* const argv[]) {
                 dumpTypeFlags |= TYPE_STABILITY;
             } else if (!strcmp(longOptions[optionIndex].name, "thread")) {
                 dumpTypeFlags |= TYPE_THREAD;
+            } else if (!strcmp(longOptions[optionIndex].name, "clients")) {
+                dumpTypeFlags |= TYPE_CLIENTS;
             }
             break;
 
@@ -373,6 +377,35 @@ static status_t dumpThreadsToFd(const sp<IBinder>& service, const unique_fd& fd)
     return OK;
 }
 
+static status_t dumpClientsToFd(const sp<IBinder>& service, const unique_fd& fd) {
+    std::string clientPids;
+    const auto remoteBinder = service->remoteBinder();
+    if (remoteBinder == nullptr) {
+        WriteStringToFd("Client PIDs are not available for local binders.\n", fd.get());
+        return OK;
+    }
+    const auto handle = remoteBinder->getDebugBinderHandle();
+    if (handle == std::nullopt) {
+        return OK;
+    }
+    std::vector<pid_t> pids;
+    pid_t myPid = getpid();
+    pid_t servicePid;
+    status_t status = service->getDebugPid(&servicePid);
+    if (status != OK) {
+        return status;
+    }
+    status =
+        getBinderClientPids(BinderDebugContext::BINDER, myPid, servicePid, handle.value(), &pids);
+    if (status != OK) {
+        return status;
+    }
+    pids.erase(std::remove_if(pids.begin(), pids.end(), [&](pid_t pid) { return pid == myPid; }),
+               pids.end());
+    WriteStringToFd("Client PIDs: " + ::android::base::Join(pids, ", ") + "\n", fd.get());
+    return OK;
+}
+
 static void reportDumpError(const String16& serviceName, status_t error, const char* context) {
     if (error == OK) return;
 
@@ -413,6 +446,10 @@ status_t Dumpsys::startDumpThread(int dumpTypeFlags, const String16& serviceName
             status_t err = dumpThreadsToFd(service, remote_end);
             reportDumpError(serviceName, err, "dumping thread info");
         }
+        if (dumpTypeFlags & TYPE_CLIENTS) {
+            status_t err = dumpClientsToFd(service, remote_end);
+            reportDumpError(serviceName, err, "dumping clients info");
+        }
 
         // other types always act as a header, this is usually longer
         if (dumpTypeFlags & TYPE_DUMP) {
diff --git a/cmds/dumpsys/dumpsys.h b/cmds/dumpsys/dumpsys.h
index 05c5d5e9d1..6ab1a7dcb5 100644
--- a/cmds/dumpsys/dumpsys.h
+++ b/cmds/dumpsys/dumpsys.h
@@ -52,10 +52,11 @@ class Dumpsys {
     static void setServiceArgs(Vector<String16>& args, bool asProto, int priorityFlags);
 
     enum Type {
-        TYPE_DUMP = 0x1,      // dump using `dump` function
-        TYPE_PID = 0x2,       // dump pid of server only
-        TYPE_STABILITY = 0x4, // dump stability information of server
-        TYPE_THREAD = 0x8,    // dump thread usage of server only
+        TYPE_DUMP = 0x1,       // dump using `dump` function
+        TYPE_PID = 0x2,        // dump pid of server only
+        TYPE_STABILITY = 0x4,  // dump stability information of server
+        TYPE_THREAD = 0x8,     // dump thread usage of server only
+        TYPE_CLIENTS = 0x10,   // dump pid of clients
     };
 
     /**
diff --git a/cmds/dumpsys/tests/dumpsys_test.cpp b/cmds/dumpsys/tests/dumpsys_test.cpp
index 312f4d714a..fa63db5533 100644
--- a/cmds/dumpsys/tests/dumpsys_test.cpp
+++ b/cmds/dumpsys/tests/dumpsys_test.cpp
@@ -627,6 +627,29 @@ TEST_F(DumpsysTest, ListServiceWithThread) {
     AssertOutputFormat(format);
 }
 
+// Tests 'dumpsys --clients'
+TEST_F(DumpsysTest, ListAllServicesWithClients) {
+    ExpectListServices({"Locksmith", "Valet"});
+    ExpectCheckService("Locksmith");
+    ExpectCheckService("Valet");
+
+    CallMain({"--clients"});
+
+    AssertRunningServices({"Locksmith", "Valet"});
+
+    const std::string format("(.|\n)*((Client PIDs are not available for local binders.)(.|\n)*){2}");
+    AssertOutputFormat(format);
+}
+
+// Tests 'dumpsys --clients service_name'
+TEST_F(DumpsysTest, ListServiceWithClients) {
+    ExpectCheckService("Locksmith");
+
+    CallMain({"--clients", "Locksmith"});
+
+    const std::string format("Client PIDs are not available for local binders.\n");
+    AssertOutputFormat(format);
+}
 // Tests 'dumpsys --thread --stability'
 TEST_F(DumpsysTest, ListAllServicesWithMultipleOptions) {
     ExpectListServices({"Locksmith", "Valet"});
diff --git a/libs/binderdebug/BinderDebug.cpp b/libs/binderdebug/BinderDebug.cpp
index b435dba197..d086b49a7b 100644
--- a/libs/binderdebug/BinderDebug.cpp
+++ b/libs/binderdebug/BinderDebug.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/strings.h>
 #include <binder/Binder.h>
@@ -116,4 +117,60 @@ status_t getBinderPidInfo(BinderDebugContext context, pid_t pid, BinderPidInfo*
     return ret;
 }
 
+status_t getBinderClientPids(BinderDebugContext context, pid_t pid, pid_t servicePid,
+                             int32_t handle, std::vector<pid_t>* pids) {
+    std::smatch match;
+    static const std::regex kNodeNumber("^\\s+ref \\d+:\\s+desc\\s+(\\d+)\\s+node\\s+(\\d+).*");
+    std::string contextStr = contextToString(context);
+    int32_t node;
+    status_t ret = scanBinderContext(pid, contextStr, [&](const std::string& line) {
+        if (std::regex_search(line, match, kNodeNumber)) {
+            const std::string& descString = match.str(1);
+            int32_t desc;
+            if (!::android::base::ParseInt(descString.c_str(), &desc)) {
+                LOG(ERROR) << "Failed to parse desc int: " << descString;
+                return;
+            }
+            if (handle != desc) {
+                return;
+            }
+            const std::string& nodeString = match.str(2);
+            if (!::android::base::ParseInt(nodeString.c_str(), &node)) {
+                LOG(ERROR) << "Failed to parse node int: " << nodeString;
+                return;
+            }
+            return;
+        }
+        return;
+    });
+    if (ret != OK) {
+        return ret;
+    }
+    static const std::regex kClients("^\\s+node\\s+(\\d+).*proc\\s+([\\d+\\s*]*)");
+    ret = scanBinderContext(servicePid, contextStr, [&](const std::string& line) {
+        if (std::regex_search(line, match, kClients)) {
+            const std::string nodeString = match.str(1);
+            int32_t matchedNode;
+            if (!::android::base::ParseInt(nodeString.c_str(), &matchedNode)) {
+                LOG(ERROR) << "Failed to parse node int: " << nodeString;
+                return;
+            }
+            if (node != matchedNode) {
+                return;
+            }
+            const std::string clients = match.str(2);
+            for (const std::string& pidStr : base::Split(clients, " ")) {
+                int32_t pid;
+                if (!::android::base::ParseInt(pidStr, &pid)) {
+                    return;
+                }
+                pids->push_back(pid);
+            }
+            return;
+        }
+        return;
+    });
+    return ret;
+}
+
 } // namespace  android
diff --git a/libs/binderdebug/include/binderdebug/BinderDebug.h b/libs/binderdebug/include/binderdebug/BinderDebug.h
index 14a0ef3672..dfd5a7cc3e 100644
--- a/libs/binderdebug/include/binderdebug/BinderDebug.h
+++ b/libs/binderdebug/include/binderdebug/BinderDebug.h
@@ -32,6 +32,14 @@ enum class BinderDebugContext {
     VNDBINDER,
 };
 
+/**
+ * pid is the pid of the service
+ */
 status_t getBinderPidInfo(BinderDebugContext context, pid_t pid, BinderPidInfo* pidInfo);
+/**
+ * pid is typically the pid of this process that is making the query
+ */
+status_t getBinderClientPids(BinderDebugContext context, pid_t pid, pid_t servicePid,
+                             int32_t handle, std::vector<pid_t>* pids);
 
 } // namespace  android