libsnapshot: Remove special-case code for first-stage init.

Because init needs tighter integration with how to launch snapuserd,
this code will be moved directly into init instead.

Bug: 173476209
Test: manual test
Change-Id: Ibce3bac9699620882eae44188d937d4900f022d3

fs_mgr/libsnapshot/device_info.cpp

@@ -120,9 +120,5 @@ bool DeviceInfo::SetSlotAsUnbootable([[maybe_unused]] unsigned int slot) {
 #endif
 }
 
-std::string DeviceInfo::GetSnapuserdFirstStagePidVar() const {
-    return kSnapuserdFirstStagePidVar;
-}
-
 }  // namespace snapshot
 }  // namespace android

fs_mgr/libsnapshot/device_info.h

@@ -39,7 +39,6 @@ class DeviceInfo final : public SnapshotManager::IDeviceInfo {
     bool SetBootControlMergeStatus(MergeStatus status) override;
     bool SetSlotAsUnbootable(unsigned int slot) override;
     bool IsRecovery() const override;
-    std::string GetSnapuserdFirstStagePidVar() const override;
 
   private:
     bool EnsureBootHal();

fs_mgr/libsnapshot/include/libsnapshot/mock_device_info.h

@@ -32,7 +32,6 @@ class MockDeviceInfo : public SnapshotManager::IDeviceInfo {
     MOCK_METHOD(bool, SetBootControlMergeStatus, (MergeStatus status), (override));
     MOCK_METHOD(bool, SetSlotAsUnbootable, (unsigned int slot), (override));
     MOCK_METHOD(bool, IsRecovery, (), (const, override));
-    MOCK_METHOD(std::string, GetSnapuserdFirstStagePidVar, (), (const, override));
 };
 
 }  // namespace android::snapshot

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

@@ -107,7 +107,6 @@ class ISnapshotManager {
         virtual bool SetSlotAsUnbootable(unsigned int slot) = 0;
         virtual bool IsRecovery() const = 0;
         virtual bool IsTestDevice() const { return false; }
-        virtual std::string GetSnapuserdFirstStagePidVar() const = 0;
     };
     virtual ~ISnapshotManager() = default;
 

fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h

@@ -30,7 +30,6 @@ namespace snapshot {
 
 static constexpr uint32_t PACKET_SIZE = 512;
 
-static constexpr char kSnapuserdSocketFirstStage[] = "snapuserd_first_stage";
 static constexpr char kSnapuserdSocket[] = "snapuserd";
 
 static constexpr char kSnapuserdFirstStagePidVar[] = "FIRST_STAGE_SNAPUSERD_PID";
@@ -38,10 +37,6 @@ static constexpr char kSnapuserdFirstStagePidVar[] = "FIRST_STAGE_SNAPUSERD_PID"
 // Ensure that the second-stage daemon for snapuserd is running.
 bool EnsureSnapuserdStarted();
 
-// Start the first-stage version of snapuserd, returning its pid. This is used
-// by first-stage init, as well as vts_libsnapshot_test. On failure, -1 is returned.
-pid_t StartFirstStageSnapuserd();
-
 class SnapuserdClient {
   private:
     android::base::unique_fd sockfd_;

fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h

@@ -96,7 +96,6 @@ class TestDeviceInfo : public SnapshotManager::IDeviceInfo {
         return true;
     }
     bool IsTestDevice() const override { return true; }
-    std::string GetSnapuserdFirstStagePidVar() const override { return {}; }
 
     bool IsSlotUnbootable(uint32_t slot) { return unbootable_slots_.count(slot) != 0; }
 

fs_mgr/libsnapshot/snapshot.cpp

@@ -1402,24 +1402,6 @@ bool SnapshotManager::PerformSecondStageTransition() {
         LOG(ERROR) << "Could not transition all snapuserd consumers.";
         return false;
     }
-
-    std::string pid_var = device_->GetSnapuserdFirstStagePidVar();
-    if (pid_var.empty()) {
-        return true;
-    }
-
-    int pid;
-    const char* pid_str = getenv(pid_var.c_str());
-    if (pid_str && android::base::ParseInt(pid_str, &pid)) {
-        if (kill(pid, SIGTERM) < 0 && errno != ESRCH) {
-            LOG(ERROR) << "kill snapuserd failed";
-            return false;
-        }
-    } else {
-        LOG(ERROR) << "Could not find or parse " << kSnapuserdFirstStagePidVar
-                   << " for snapuserd pid";
-        return false;
-    }
     return true;
 }
 
@@ -1764,15 +1746,6 @@ bool SnapshotManager::MapAllPartitions(LockedFile* lock, const std::string& supe
         }
     }
 
-    if (use_first_stage_snapuserd_) {
-        // Remove the first-stage socket as a precaution, there is no need to
-        // access the daemon anymore and we'll be killing it once second-stage
-        // is running.
-        auto socket = ANDROID_SOCKET_DIR + "/"s + kSnapuserdSocketFirstStage;
-        snapuserd_client_ = nullptr;
-        unlink(socket.c_str());
-    }
-
     LOG(INFO) << "Created logical partitions with snapshot.";
     return true;
 }
@@ -2419,28 +2392,11 @@ bool SnapshotManager::EnsureSnapuserdConnected() {
         return true;
     }
 
-    std::string socket;
-    if (use_first_stage_snapuserd_) {
-        auto pid = StartFirstStageSnapuserd();
-        if (pid < 0) {
-            LOG(ERROR) << "Failed to start snapuserd";
-            return false;
-        }
-
-        auto pid_str = std::to_string(static_cast<int>(pid));
-        if (setenv(kSnapuserdFirstStagePidVar, pid_str.c_str(), 1) < 0) {
-            PLOG(ERROR) << "setenv failed storing the snapuserd pid";
-        }
-
-        socket = kSnapuserdSocketFirstStage;
-    } else {
-        if (!EnsureSnapuserdStarted()) {
-            return false;
-        }
-        socket = kSnapuserdSocket;
+    if (!use_first_stage_snapuserd_ && !EnsureSnapuserdStarted()) {
+        return false;
     }
 
-    snapuserd_client_ = SnapuserdClient::Connect(socket, 10s);
+    snapuserd_client_ = SnapuserdClient::Connect(kSnapuserdSocket, 10s);
     if (!snapuserd_client_) {
         LOG(ERROR) << "Unable to connect to snapuserd";
         return false;

fs_mgr/libsnapshot/snapshot_fuzz_utils.h

@@ -124,7 +124,6 @@ class SnapshotFuzzDeviceInfo : public ISnapshotManager::IDeviceInfo {
         return data_->allow_set_slot_as_unbootable();
     }
     bool IsRecovery() const override { return data_->is_recovery(); }
-    std::string GetSnapuserdFirstStagePidVar() const override { return {}; }
 
     void SwitchSlot() { switched_slot_ = !switched_slot_; }
 

fs_mgr/libsnapshot/snapshot_test.cpp

@@ -1760,9 +1760,6 @@ TEST_F(SnapshotUpdateTest, DaemonTransition) {
         GTEST_SKIP() << "Skipping Virtual A/B Compression test";
     }
 
-    AutoKill auto_kill(StartFirstStageSnapuserd());
-    ASSERT_TRUE(auto_kill.valid());
-
     // Ensure a connection to the second-stage daemon, but use the first-stage
     // code paths thereafter.
     ASSERT_TRUE(sm->EnsureSnapuserdConnected());

fs_mgr/libsnapshot/snapuserd_client.cpp

@@ -54,25 +54,6 @@ bool EnsureSnapuserdStarted() {
     return true;
 }
 
-pid_t StartFirstStageSnapuserd() {
-    pid_t pid = fork();
-    if (pid < 0) {
-        PLOG(ERROR) << "fork failed";
-        return pid;
-    }
-    if (pid != 0) {
-        return pid;
-    }
-
-    std::string arg0 = "/system/bin/snapuserd";
-    std::string arg1 = kSnapuserdSocketFirstStage;
-    char* const argv[] = {arg0.data(), arg1.data(), nullptr};
-    if (execv(arg0.c_str(), argv) < 0) {
-        PLOG(FATAL) << "execv failed";
-    }
-    return pid;
-}
-
 SnapuserdClient::SnapuserdClient(android::base::unique_fd&& sockfd) : sockfd_(std::move(sockfd)) {}
 
 static inline bool IsRetryErrno() {