Don't fall back to copy during rollback tests (5/n)

1. 'persist.rollback.is_test' is set to 1 during rollback tests
2. don't fall back to copy if hardlink fails during rollback tests
3. This gives us insight into how enable-rollback-by-hardlink works
   and how it fails in the field

Bug: 168562373
Test: atest MultiUserRollbackTest \
            NetworkStagedRollbackTest \
            RollbackTest \
            StagedRollbackTest
Change-Id: If1590fdf96e25105936a930b3ec7225ecec4bf0d

5 files changed, 41 insertions, 10 deletions

diff --git a/services/core/java/com/android/server/rollback/RollbackStore.java b/services/core/java/com/android/server/rollback/RollbackStore.java
index 3a08ddc6c405..fc62f5be801c 100644
--- a/services/core/java/com/android/server/rollback/RollbackStore.java
+++ b/services/core/java/com/android/server/rollback/RollbackStore.java
@@ -24,6 +24,7 @@ import android.content.pm.VersionedPackage;
 import android.content.rollback.PackageRollbackInfo;
 import android.content.rollback.PackageRollbackInfo.RestoreInfo;
 import android.content.rollback.RollbackInfo;
+import android.os.SystemProperties;
 import android.os.UserHandle;
 import android.system.ErrnoException;
 import android.system.Os;
@@ -227,6 +228,15 @@ class RollbackStore {
                 packageSessionIds, extensionVersions);
     }
 
+    private static boolean isLinkPossible(File oldFile, File newFile) {
+        try {
+            return Os.stat(oldFile.getAbsolutePath()).st_dev
+                    == Os.stat(newFile.getAbsolutePath()).st_dev;
+        } catch (ErrnoException ignore) {
+            return false;
+        }
+    }
+
     /**
      * Creates a backup copy of an apk or apex for a package.
      * For packages containing splits, this method should be called for each
@@ -239,16 +249,29 @@ class RollbackStore {
         targetDir.mkdirs();
         File targetFile = new File(targetDir, sourceFile.getName());
 
-        try {
-            // Create a hard link to avoid copy
-            // TODO(b/168562373)
-            // Linking between non-encrypted and encrypted is not supported and we have
-            // encrypted /data/rollback and non-encrypted /data/apex/active. For now this works
-            // because we happen to store encrypted files under /data/apex/active which is no
-            // longer the case when compressed apex rolls out. We have to handle this case in
-            // order not to fall back to copy.
-            Os.link(sourceFile.getAbsolutePath(), targetFile.getAbsolutePath());
-        } catch (ErrnoException ignore) {
+        boolean fallbackToCopy = !isLinkPossible(sourceFile, targetFile);
+        if (!fallbackToCopy) {
+            try {
+                // Create a hard link to avoid copy
+                // TODO(b/168562373)
+                // Linking between non-encrypted and encrypted is not supported and we have
+                // encrypted /data/rollback and non-encrypted /data/apex/active. For now this works
+                // because we happen to store encrypted files under /data/apex/active which is no
+                // longer the case when compressed apex rolls out. We have to handle this case in
+                // order not to fall back to copy.
+                Os.link(sourceFile.getAbsolutePath(), targetFile.getAbsolutePath());
+            } catch (ErrnoException e) {
+                boolean isRollbackTest =
+                        SystemProperties.getBoolean("persist.rollback.is_test", false);
+                if (isRollbackTest) {
+                    throw new IOException(e);
+                } else {
+                    fallbackToCopy = true;
+                }
+            }
+        }
+
+        if (fallbackToCopy) {
             // Fall back to copy if hardlink can't be created
             Files.copy(sourceFile.toPath(), targetFile.toPath());
         }
diff --git a/tests/RollbackTest/MultiUserRollbackTest.xml b/tests/RollbackTest/MultiUserRollbackTest.xml
index 2f62af1856da..8fa0510d9e71 100644
--- a/tests/RollbackTest/MultiUserRollbackTest.xml
+++ b/tests/RollbackTest/MultiUserRollbackTest.xml
@@ -20,6 +20,8 @@
         <option name="run-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.A" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
+        <option name="run-command" value="setprop persist.rollback.is_test 1" />
+        <option name="teardown-command" value="setprop persist.rollback.is_test 0" />
     </target_preparer>
     <test class="com.android.tradefed.testtype.HostTest" >
         <option name="class" value="com.android.tests.rollback.host.MultiUserRollbackTest" />
diff --git a/tests/RollbackTest/NetworkStagedRollbackTest.xml b/tests/RollbackTest/NetworkStagedRollbackTest.xml
index 2ab907a59298..13f603140aee 100644
--- a/tests/RollbackTest/NetworkStagedRollbackTest.xml
+++ b/tests/RollbackTest/NetworkStagedRollbackTest.xml
@@ -24,6 +24,8 @@
         <option name="run-command" value="am broadcast -a 'com.google.android.gms.phenotype.FLAG_OVERRIDE' --es package &quot;com.google.android.gms.platformconfigurator&quot; --es user '\\*' --esa flags &quot;ModuleConfig__versioned_immediate_commit_packages&quot; --esa types &quot;bytes&quot; --esa values &quot;Cm5vdGFwYWNrYWdlOgA=&quot; com.google.android.gms" />
         <option name="teardown-command" value="am broadcast -a 'com.google.android.gms.phenotype.FLAG_OVERRIDE' --es action delete --es package &quot;com.google.android.gms.platformconfigurator&quot; --es user '\*' --esa flag &quot;ModuleConfig__immediate_commit_packages&quot; com.google.android.gms" />
         <option name="teardown-command" value="am broadcast -a 'com.google.android.gms.phenotype.FLAG_OVERRIDE' --es action delete --es package &quot;com.google.android.gms.platformconfigurator&quot; --es user '\*' --esa flag &quot;ModuleConfig__versioned_immediate_commit_packages&quot; com.google.android.gms" />
+        <option name="run-command" value="setprop persist.rollback.is_test 1" />
+        <option name="teardown-command" value="setprop persist.rollback.is_test 0" />
     </target_preparer>
     <test class="com.android.tradefed.testtype.HostTest" >
         <option name="class" value="com.android.tests.rollback.host.NetworkStagedRollbackTest" />
diff --git a/tests/RollbackTest/RollbackTest.xml b/tests/RollbackTest/RollbackTest.xml
index 7b85cc84f1f5..fbb6e46e1721 100644
--- a/tests/RollbackTest/RollbackTest.xml
+++ b/tests/RollbackTest/RollbackTest.xml
@@ -27,6 +27,8 @@
         <option name="run-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.A" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
+        <option name="run-command" value="setprop persist.rollback.is_test 1" />
+        <option name="teardown-command" value="setprop persist.rollback.is_test 0" />
     </target_preparer>
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
         <option name="package" value="com.android.tests.rollback" />
diff --git a/tests/RollbackTest/StagedRollbackTest.xml b/tests/RollbackTest/StagedRollbackTest.xml
index 83fef8e0a04b..0ca4dafae59d 100644
--- a/tests/RollbackTest/StagedRollbackTest.xml
+++ b/tests/RollbackTest/StagedRollbackTest.xml
@@ -24,6 +24,8 @@
         <option name="run-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.A" />
         <option name="teardown-command" value="pm uninstall com.android.cts.install.lib.testapp.B" />
+        <option name="run-command" value="setprop persist.rollback.is_test 1" />
+        <option name="teardown-command" value="setprop persist.rollback.is_test 0" />
     </target_preparer>
     <test class="com.android.tradefed.testtype.HostTest" >
         <option name="class" value="com.android.tests.rollback.host.StagedRollbackTest" />