Merge "Support wrapping app processes to inject debug instrumentation. Bug: 4437846"

Author: Jeff Brown

cmds/app_process/app_main.cpp

@@ -128,10 +128,7 @@ int main(int argc, const char* const argv[])
     mArgLen--;
 
     AppRuntime runtime;
-    const char *arg;
-    const char *argv0;
-
-    argv0 = argv[0];
+    const char* argv0 = argv[0];
 
     // Process command line arguments
     // ignore argv[0]
@@ -142,39 +139,53 @@ int main(int argc, const char* const argv[])
 
     int i = runtime.addVmArguments(argc, argv);
 
-    // Next arg is parent directory
-    if (i < argc) {
-        runtime.mParentDir = argv[i++];
-    }
-
-    // Next arg is startup classname or "--zygote"
-    if (i < argc) {
-        arg = argv[i++];
-        if (0 == strcmp("--zygote", arg)) {
-            bool startSystemServer = (i < argc) ? 
-                    strcmp(argv[i], "--start-system-server") == 0 : false;
-            setArgv0(argv0, "zygote");
-            set_process_name("zygote");
-            runtime.start("com.android.internal.os.ZygoteInit",
-                startSystemServer);
+    // Parse runtime arguments.  Stop at first unrecognized option.
+    bool zygote = false;
+    bool startSystemServer = false;
+    bool application = false;
+    const char* parentDir = NULL;
+    const char* niceName = NULL;
+    const char* className = NULL;
+    while (i < argc) {
+        const char* arg = argv[i++];
+        if (!parentDir) {
+            parentDir = arg;
+        } else if (strcmp(arg, "--zygote") == 0) {
+            zygote = true;
+            niceName = "zygote";
+        } else if (strcmp(arg, "--start-system-server") == 0) {
+            startSystemServer = true;
+        } else if (strcmp(arg, "--application") == 0) {
+            application = true;
+        } else if (strncmp(arg, "--nice-name=", 12) == 0) {
+            niceName = arg + 12;
         } else {
-            set_process_name(argv0);
-
-            runtime.mClassName = arg;
+            className = arg;
+            break;
+        }
+    }
 
-            // Remainder of args get passed to startup class main()
-            runtime.mArgC = argc-i;
-            runtime.mArgV = argv+i;
+    if (niceName && *niceName) {
+        setArgv0(argv0, niceName);
+        set_process_name(niceName);
+    }
 
-            LOGV("App process is starting with pid=%d, class=%s.\n",
-                 getpid(), runtime.getClassName());
-            runtime.start();
-        }
+    runtime.mParentDir = parentDir;
+
+    if (zygote) {
+        runtime.start("com.android.internal.os.ZygoteInit",
+                startSystemServer ? "start-system-server" : "");
+    } else if (className) {
+        // Remainder of args get passed to startup class main()
+        runtime.mClassName = className;
+        runtime.mArgC = argc - i;
+        runtime.mArgV = argv + i;
+        runtime.start("com.android.internal.os.RuntimeInit",
+                application ? "application" : "tool");
     } else {
         LOG_ALWAYS_FATAL("app_process: no class name or --zygote supplied.");
         fprintf(stderr, "Error: no class name or --zygote supplied.\n");
         app_usage();
         return 10;
     }
-
 }

cmds/runtime/main_runtime.cpp

@@ -497,8 +497,8 @@ int main(int argc, char* const argv[])
     } else {
 #ifndef HAVE_ANDROID_OS
         QuickRuntime* runt = new QuickRuntime();
-        runt->start("com/android/server/SystemServer", 
-                    false /* spontaneously fork system server from zygote */);
+        runt->start("com/android/server/SystemServer",
+                    "" /* spontaneously fork system server from zygote */);
 #endif
     }
 

core/java/android/os/Process.java

@@ -257,13 +257,12 @@ public class Process {
      * @param enableDebugger True if debugging should be enabled for this process.
      * @param zygoteArgs Additional arguments to supply to the zygote process.
      * 
-     * @return int If > 0 the pid of the new process; if 0 the process is
-     *         being emulated by a thread
+     * @return An object that describes the result of the attempt to start the process.
      * @throws RuntimeException on fatal start failure
      * 
      * {@hide}
      */
-    public static final int start(final String processClass,
+    public static final ProcessStartResult start(final String processClass,
                                   final String niceName,
                                   int uid, int gid, int[] gids,
                                   int debugFlags,
@@ -294,16 +293,15 @@ public void run() {
             } else {
                 new Thread(runnable).start();
             }
-            
-            return 0;
+            return new ProcessStartResult();
         }
     }
 
     /**
      * Start a new process.  Don't supply a custom nice name.
      * {@hide}
      */
-    public static final int start(String processClass, int uid, int gid,
+    public static final ProcessStartResult start(String processClass, int uid, int gid,
             int[] gids, int debugFlags, String[] zygoteArgs) {
         return start(processClass, "", uid, gid, gids, 
                 debugFlags, zygoteArgs);
@@ -418,14 +416,11 @@ private static void openZygoteSocketIfNeeded()
      * and returns the child's pid. Please note: the present implementation
      * replaces newlines in the argument list with spaces.
      * @param args argument list
-     * @return PID of new child process
+     * @return An object that describes the result of the attempt to start the process.
      * @throws ZygoteStartFailedEx if process start failed for any reason
      */
-    private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
+    private static ProcessStartResult zygoteSendArgsAndGetResult(ArrayList<String> args)
             throws ZygoteStartFailedEx {
-
-        int pid;
-
         openZygoteSocketIfNeeded();
 
         try {
@@ -436,7 +431,8 @@ private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
              * b) a number of newline-separated argument strings equal to count
              *
              * After the zygote process reads these it will write the pid of
-             * the child or -1 on failure.
+             * the child or -1 on failure, followed by boolean to
+             * indicate whether a wrapper process was used.
              */
 
             sZygoteWriter.write(Integer.toString(args.size()));
@@ -456,11 +452,13 @@ private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
             sZygoteWriter.flush();
 
             // Should there be a timeout on this?
-            pid = sZygoteInputStream.readInt();
-
-            if (pid < 0) {
+            ProcessStartResult result = new ProcessStartResult();
+            result.pid = sZygoteInputStream.readInt();
+            if (result.pid < 0) {
                 throw new ZygoteStartFailedEx("fork() failed");
             }
+            result.usingWrapper = sZygoteInputStream.readBoolean();
+            return result;
         } catch (IOException ex) {
             try {
                 if (sZygoteSocket != null) {
@@ -475,8 +473,6 @@ private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
 
             throw new ZygoteStartFailedEx(ex);
         }
-
-        return pid;
     }
 
     /**
@@ -490,18 +486,16 @@ private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
      * new process should setgroup() to.
      * @param enableDebugger True if debugging should be enabled for this process.
      * @param extraArgs Additional arguments to supply to the zygote process.
-     * @return PID
+     * @return An object that describes the result of the attempt to start the process.
      * @throws ZygoteStartFailedEx if process start failed for any reason
      */
-    private static int startViaZygote(final String processClass,
+    private static ProcessStartResult startViaZygote(final String processClass,
                                   final String niceName,
                                   final int uid, final int gid,
                                   final int[] gids,
                                   int debugFlags,
                                   String[] extraArgs)
                                   throws ZygoteStartFailedEx {
-        int pid;
-
         synchronized(Process.class) {
             ArrayList<String> argsForZygote = new ArrayList<String>();
 
@@ -553,15 +547,9 @@ private static int startViaZygote(final String processClass,
                     argsForZygote.add(arg);
                 }
             }
-            
-            pid = zygoteSendArgsAndGetPid(argsForZygote);
-        }
 
-        if (pid <= 0) {
-            throw new ZygoteStartFailedEx("zygote start failed:" + pid);
+            return zygoteSendArgsAndGetResult(argsForZygote);
         }
-
-        return pid;
     }
 
     /**
@@ -615,6 +603,20 @@ public static final int getUidForPid(int pid) {
         return (int) procStatusValues[0];
     }
 
+    /**
+     * Returns the parent process id for a currently running process.
+     * @param pid the process id
+     * @return the parent process id of the process, or -1 if the process is not running.
+     * @hide
+     */
+    public static final int getParentPid(int pid) {
+        String[] procStatusLabels = { "PPid:" };
+        long[] procStatusValues = new long[1];
+        procStatusValues[0] = -1;
+        Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
+        return (int) procStatusValues[0];
+    }
+
     /**
      * Set the priority of a thread, based on Linux priorities.
      * 
@@ -826,4 +828,21 @@ public static final native boolean parseProcLine(byte[] buffer, int startIndex,
      * @hide
      */
     public static final native long getPss(int pid);
+
+    /**
+     * Specifies the outcome of having started a process.
+     * @hide
+     */
+    public static final class ProcessStartResult {
+        /**
+         * The PID of the newly started process.
+         * Always >= 0.  (If the start failed, an exception will have been thrown instead.)
+         */
+        public int pid;
+
+        /**
+         * True if the process was started with a wrapper attached.
+         */
+        public boolean usingWrapper;
+    }
 }