Add a method to Process to get uid for a pid.

Use the uids to track native processes. Cache the uids to avoid
checking /proc every time.

3 files changed, 19 insertions, 8 deletions

diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index 333c7cb..1214abc 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -573,7 +573,21 @@ public class Process {
      * directly to a gid.
      */
     public static final native int getGidForName(String name);
-    
+
+    /**
+     * Returns a uid for a currently running process.
+     * @param pid the process id
+     * @return the uid of the process, or -1 if the process is not running.
+     * @hide pending API council review
+     */
+    public static final int getUidForPid(int pid) {
+        String[] procStatusLabels = { "Uid:" };
+        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.
      * 
diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index fc4a9c4..a03802d 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -2836,14 +2836,12 @@ public final class BatteryStatsImpl extends BatteryStats {
      * @param name process name
      * @return the statistics object for the process
      */
-    public Uid.Proc getProcessStatsLocked(String name) {
+    public Uid.Proc getProcessStatsLocked(String name, int pid) {
         int uid;
         if (mUidCache.containsKey(name)) {
             uid = mUidCache.get(name);
         } else {
-            // TODO: Find the actual uid from /proc/pid/status. For now use the hashcode of the
-            // process name
-            uid = name.hashCode();
+            uid = Process.getUidForPid(pid);
             mUidCache.put(name, uid);
         }
         Uid u = getUidStatsLocked(uid);
diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 0d9d2b0..fd1dfc8 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -1518,8 +1518,7 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                 }
             }
             
-            final BatteryStatsImpl bstats =
-                    (BatteryStatsImpl) mBatteryStatsService.getActiveStatistics();
+            final BatteryStatsImpl bstats = mBatteryStatsService.getActiveStatistics();
             synchronized(bstats) {
                 synchronized(mPidsSelfLocked) {
                     if (haveNewCpuStats) {
@@ -1534,7 +1533,7 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                                     ps.addCpuTimeLocked(st.rel_utime, st.rel_stime);
                                 } else {
                                     BatteryStatsImpl.Uid.Proc ps =
-                                            bstats.getProcessStatsLocked(st.name);
+                                            bstats.getProcessStatsLocked(st.name, st.pid);
                                     if (ps != null) {
                                         ps.addCpuTimeLocked(st.rel_utime, st.rel_stime);
                                     }