Change abortChanges to take a message and bool

abortChanges will attempt to pass a reboot message, and will only reboot
if the device is currently checkpointing. Additionally, it can opt to
attempt to prevent future attempts. This only works for non-bootloader
controlled updates. Failures are ignored, as it will always reboot the
device. In the unlikely event of such a failure, the device will
continue to retry as though you did not ask to prevent future attempts.

Test: vdc checkpoint abortChanges abort_retry_test 1
      vdc checkpoint abortChanges abort_noretry_test 0

Change-Id: I7b6214765a1faaf4fd193c73331696b53ae572d2

Checkpoint.cpp

@@ -180,9 +180,37 @@ Status cp_commitChanges() {
     return Status::ok();
 }
 
-Status cp_abortChanges() {
-    android_reboot(ANDROID_RB_RESTART2, 0, nullptr);
-    return Status::ok();
+namespace {
+void abort_metadata_file() {
+    std::string oldContent, newContent;
+    int retry = 0;
+    struct stat st;
+    int result = stat(kMetadataCPFile.c_str(), &st);
+
+    // If the file doesn't exist, we aren't managing a checkpoint retry counter
+    if (result != 0) return;
+    if (!android::base::ReadFileToString(kMetadataCPFile, &oldContent)) {
+        PLOG(ERROR) << "Failed to read checkpoint file";
+        return;
+    }
+    std::string retryContent = oldContent.substr(0, oldContent.find_first_of(" "));
+
+    if (!android::base::ParseInt(retryContent, &retry)) {
+        PLOG(ERROR) << "Could not parse retry count";
+        return;
+    }
+    if (retry > 0) {
+        newContent = "0";
+        if (!android::base::WriteStringToFile(newContent, kMetadataCPFile))
+            PLOG(ERROR) << "Could not write checkpoint file";
+    }
+}
+}  // namespace
+
+void cp_abortChanges(const std::string& message, bool retry) {
+    if (!cp_needsCheckpoint()) return;
+    if (!retry) abort_metadata_file();
+    android_reboot(ANDROID_RB_RESTART2, 0, message.c_str());
 }
 
 bool cp_needsRollback() {

Checkpoint.h

@@ -33,7 +33,7 @@ android::binder::Status cp_startCheckpoint(int retry);
 
 android::binder::Status cp_commitChanges();
 
-android::binder::Status cp_abortChanges();
+void cp_abortChanges(const std::string& message, bool retry);
 
 bool cp_needsRollback();
 

VoldNativeService.cpp

@@ -865,11 +865,12 @@ binder::Status VoldNativeService::markBootAttempt() {
     return cp_markBootAttempt();
 }
 
-binder::Status VoldNativeService::abortChanges() {
+binder::Status VoldNativeService::abortChanges(const std::string& message, bool retry) {
     ENFORCE_UID(AID_SYSTEM);
     ACQUIRE_LOCK;
 
-    return cp_abortChanges();
+    cp_abortChanges(message, retry);
+    return ok();
 }
 
 binder::Status VoldNativeService::supportsCheckpoint(bool* _aidl_return) {

VoldNativeService.h

@@ -129,7 +129,7 @@ class VoldNativeService : public BinderService<VoldNativeService>, public os::Bn
     binder::Status restoreCheckpoint(const std::string& mountPoint);
     binder::Status restoreCheckpointPart(const std::string& mountPoint, int count);
     binder::Status markBootAttempt();
-    binder::Status abortChanges();
+    binder::Status abortChanges(const std::string& message, bool retry);
     binder::Status supportsCheckpoint(bool* _aidl_return);
     binder::Status supportsBlockCheckpoint(bool* _aidl_return);
     binder::Status supportsFileCheckpoint(bool* _aidl_return);

binder/android/os/IVold.aidl

@@ -99,7 +99,7 @@ interface IVold {
     void startCheckpoint(int retry);
     boolean needsCheckpoint();
     boolean needsRollback();
-    void abortChanges();
+    void abortChanges(in @utf8InCpp String device, boolean retry);
     void commitChanges();
     void prepareCheckpoint();
     void restoreCheckpoint(@utf8InCpp String device);

vdc.cpp

@@ -141,8 +141,10 @@ int main(int argc, char** argv) {
         checkStatus(vold->restoreCheckpointPart(args[2], count));
     } else if (args[0] == "checkpoint" && args[1] == "markBootAttempt" && args.size() == 2) {
         checkStatus(vold->markBootAttempt());
-    } else if (args[0] == "checkpoint" && args[1] == "abortChanges" && args.size() == 2) {
-        checkStatus(vold->abortChanges());
+    } else if (args[0] == "checkpoint" && args[1] == "abortChanges" && args.size() == 4) {
+        int retry;
+        if (!android::base::ParseInt(args[2], &retry)) exit(EINVAL);
+        checkStatus(vold->abortChanges(args[2], retry != 0));
     } else {
         LOG(ERROR) << "Raw commands are no longer supported";
         exit(EINVAL);