Don't compile all splits when installing one.

This patch consists of two broad changes :
- don't "force" dex2oat when installing a new app. this should never
  be necessary because we will always compare checksums.

- when staging a new install, we "inherit" (hard link) all compiled
  oat files from the previous install. this will ensure that we compile
  only those files that have changed, and not all of them

bug: 20889739
Change-Id: I3e14335f3bcfe76d1d24d233f53a728a6d90e8a1

2 files changed, 97 insertions, 8 deletions

diff --git a/services/core/java/com/android/server/pm/PackageInstallerSession.java b/services/core/java/com/android/server/pm/PackageInstallerSession.java
index dcf668d..1cec750 100644
--- a/services/core/java/com/android/server/pm/PackageInstallerSession.java
+++ b/services/core/java/com/android/server/pm/PackageInstallerSession.java
@@ -52,6 +52,7 @@ import android.os.Message;
 import android.os.ParcelFileDescriptor;
 import android.os.Process;
 import android.os.RemoteException;
+import android.os.SELinux;
 import android.os.UserHandle;
 import android.system.ErrnoException;
 import android.system.Os;
@@ -77,6 +78,7 @@ import java.io.File;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -163,6 +165,8 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
     private final List<File> mResolvedStagedFiles = new ArrayList<>();
     @GuardedBy("mLock")
     private final List<File> mResolvedInheritedFiles = new ArrayList<>();
+    @GuardedBy("mLock")
+    private File mInheritedFilesBase;
 
     private final Handler.Callback mHandlerCallback = new Handler.Callback() {
         @Override
@@ -511,8 +515,13 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
                 final List<File> fromFiles = mResolvedInheritedFiles;
                 final File toDir = resolveStageDir();
 
+                if (LOGD) Slog.d(TAG, "Inherited files: " + mResolvedInheritedFiles);
+                if (!mResolvedInheritedFiles.isEmpty() && mInheritedFilesBase == null) {
+                    throw new IllegalStateException("mInheritedFilesBase == null");
+                }
+
                 if (isLinkPossible(fromFiles, toDir)) {
-                    linkFiles(fromFiles, toDir);
+                    createDirsAndLinkFiles(fromFiles, toDir, mInheritedFilesBase);
                 } else {
                     // TODO: this should delegate to DCS so the system process
                     // avoids holding open FDs into containers.
@@ -690,6 +699,31 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
                     }
                 }
             }
+
+            // Inherit compiled oat directory.
+            final File packageInstallDir = (new File(app.getBaseCodePath())).getParentFile();
+            mInheritedFilesBase = packageInstallDir;
+            final File oatDir = new File(packageInstallDir, "oat");
+            if (oatDir.exists()) {
+                final File[] archSubdirs = oatDir.listFiles();
+                // Only add "oatDir" if it contains arch specific subdirs.
+                if (archSubdirs != null && archSubdirs.length > 0) {
+                    mResolvedInheritedFiles.add(oatDir);
+                }
+                final String[] instructionSets = InstructionSets.getAllDexCodeInstructionSets();
+                for (File archSubDir : archSubdirs) {
+                    // Skip any directory that isn't an ISA subdir.
+                    if (!ArrayUtils.contains(instructionSets, archSubDir.getName())) {
+                        continue;
+                    }
+
+                    List<File> oatFiles = Arrays.asList(archSubDir.listFiles());
+                    if (!oatFiles.isEmpty()) {
+                        mResolvedInheritedFiles.add(archSubDir);
+                        mResolvedInheritedFiles.addAll(oatFiles);
+                    }
+                }
+            }
         }
     }
 
@@ -768,14 +802,69 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
         return true;
     }
 
-    private static void linkFiles(List<File> fromFiles, File toDir) throws IOException {
+    /**
+     * Reparents the path of {@code file} from {@code oldBase} to {@code newBase}. {@code file}
+     * must necessarily be a subpath of {@code oldBase}. It is an error for {@code file} to have
+     * relative path components such as {@code "."} or {@code ".."}. For example, for we will
+     * reparent {@code /foo/bar/baz} to {@code /foo2/bar/baz} if {@code oldBase} was {@code /foo}
+     * and {@code newBase} was {@code /foo2}.
+     */
+    private static File reparentPath(File file, File oldBase, File newBase) throws IOException {
+        final String oldBaseStr = oldBase.getAbsolutePath();
+        final String pathStr = file.getAbsolutePath();
+
+        // Don't allow relative paths.
+        if (pathStr.contains("/.") ) {
+            throw new IOException("Invalid path (was relative) : " + pathStr);
+        }
+
+        if (pathStr.startsWith(oldBaseStr)) {
+            final String relative = pathStr.substring(oldBaseStr.length());
+            return new File(newBase, relative);
+        }
+
+        throw new IOException("File: " + pathStr + " outside base: " + oldBaseStr);
+    }
+
+    /**
+     * Recreates a directory and file structure, specified by a list of files {@code fromFiles}
+     * which are subpaths of {@code fromDir} to {@code toDir}. Directories are created with the
+     * same permissions, and regular files are linked.
+     *
+     * TODO: Move this function to installd so that the system process doesn't have to
+     * manipulate / relabel directories.
+     */
+    private static void createDirsAndLinkFiles(List<File> fromFiles, File toDir, File fromDir)
+            throws IOException {
         for (File fromFile : fromFiles) {
-            final File toFile = new File(toDir, fromFile.getName());
+            final File toFile = reparentPath(fromFile, fromDir, toDir);
+            final StructStat stat;
             try {
-                if (LOGD) Slog.d(TAG, "Linking " + fromFile + " to " + toFile);
-                Os.link(fromFile.getAbsolutePath(), toFile.getAbsolutePath());
+                stat = Os.stat(fromFile.getAbsolutePath());
             } catch (ErrnoException e) {
-                throw new IOException("Failed to link " + fromFile + " to " + toFile, e);
+                throw new IOException("Failed to stat: " + fromFile.getAbsolutePath(), e);
+            }
+
+            if (OsConstants.S_ISDIR(stat.st_mode)) {
+                if (LOGD) Slog.d(TAG, "Creating directory " + toFile.getAbsolutePath());
+                try {
+                    Os.mkdir(toFile.getAbsolutePath(), stat.st_mode);
+                } catch (ErrnoException e) {
+                    throw new IOException("Failed to create dir: " + toFile.getAbsolutePath(), e);
+                }
+
+                // We do this to ensure that the oat/ directory is created with the right
+                // label (data_dalvikcache_file) instead of apk_tmpfile.
+                if (!SELinux.restorecon(toFile)) {
+                    throw new IOException("Failed to restorecon: " + toFile.getAbsolutePath());
+                }
+            } else {
+                if (LOGD) Slog.d(TAG, "Linking " + fromFile + " to " + toFile);
+                try {
+                    Os.link(fromFile.getAbsolutePath(), toFile.getAbsolutePath());
+                } catch (ErrnoException e) {
+                    throw new IOException("Failed to link " + fromFile + " to " + toFile, e);
+                }
             }
         }
         Slog.d(TAG, "Linked " + fromFiles.size() + " files into " + toDir);
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 47e3963..7dfe836 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -11504,7 +11504,7 @@ public class PackageManagerService extends IPackageManager.Stub {
         final boolean onExternal = (((installFlags & PackageManager.INSTALL_EXTERNAL) != 0)
                 || (args.volumeUuid != null));
         boolean replace = false;
-        int scanFlags = SCAN_NEW_INSTALL | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE;
+        int scanFlags = SCAN_NEW_INSTALL | SCAN_UPDATE_SIGNATURE;
         // Result object to be returned
         res.returnCode = PackageManager.INSTALL_SUCCEEDED;
 
@@ -11705,7 +11705,7 @@ public class PackageManagerService extends IPackageManager.Stub {
 
             // Run dexopt before old package gets removed, to minimize time when app is unavailable
             int result = mPackageDexOptimizer
-                    .performDexOpt(pkg, null /* instruction sets */, true /* forceDex */,
+                    .performDexOpt(pkg, null /* instruction sets */, false /* forceDex */,
                             false /* defer */, false /* inclDependencies */);
             if (result == PackageDexOptimizer.DEX_OPT_FAILED) {
                 res.setError(INSTALL_FAILED_DEXOPT, "Dexopt failed for " + pkg.codePath);