Enable exporting of tombstones out of guest VMs

Microdroid init will start the tombstone_transmit service which will
connect to a server (thread of virtualization service).

virtualizationservice listens for incoming connections from guests VMs.
The client (tombstone_transmit in  guest) sends each tombstone file
content through a separate stream.

For each received connection, handle_tombstone would send a connect
request to tombstoned(via libtombstoned_client_rust), which provide a
file  to write the content in (actually managed by the client libary).
Once write is complete notify_completion() would send completion
notification to tombstoned (which then will close the file and rename it).

Test: atest MicrodroidHostTestCases and/or crash a process in microdroid, take and check bugreport
Bug: 202153827

Change-Id: Ifcaa5da968ef39fdd05612d3e0baca4fd1c5eaf1

microdroid/Android.bp

@@ -77,6 +77,7 @@ android_system_image {
         "linkerconfig",
         "servicemanager.microdroid",
         "tombstoned",
+        "tombstone_transmit.microdroid",
         "cgroups.json",
         "public.libraries.android.txt",
 

microdroid/bootconfig.common

@@ -1,2 +1,6 @@
 androidboot.first_stage_console = 1
 androidboot.hardware = microdroid
+
+# tombstone_transmit is enabled. Tombstones will be transmitted to the host
+# TODO(b/227443903) : Make this configurable by VM owners
+androidboot.tombstone_transmit.enabled=1

microdroid/init.rc

@@ -173,6 +173,13 @@ on post-fs-data
     mkdir /data/local 0751 root root
     mkdir /data/local/tmp 0771 shell shell
 
+on init && property:ro.boot.tombstone_transmit.enabled=1
+     start tombstone_transmit
+
+service tombstone_transmit /system/bin/tombstone_transmit.microdroid -cid 2 -port 2000
+    user root
+    group system
+
 service apexd-vm /system/bin/apexd --vm
     user root
     group system

tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java

@@ -105,7 +105,7 @@ public abstract class VirtualizationTestCaseBase extends BaseHostJUnit4Test {
     }
 
     // Run an arbitrary command in the host side and returns the result
-    private static String runOnHost(String... cmd) {
+    public static String runOnHost(String... cmd) {
         return runOnHostWithTimeout(10000, cmd);
     }
 

tests/hostside/java/android/virt/test/MicrodroidTestCase.java

@@ -22,6 +22,7 @@ import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -100,6 +101,13 @@ public class MicrodroidTestCase extends VirtualizationTestCaseBase {
                 false);
     }
 
+    // Wait until logd-init starts. The service is one of the last services that are started in
+    // the microdroid boot procedure. Therefore, waiting for the service means that we wait for
+    // the boot to complete. TODO: we need a better marker eventually.
+    private void waitForLogdInit() {
+        tryRunOnMicrodroid("watch -e \"getprop init.svc.logd-reinit | grep '^$'\"");
+    }
+
     @Test
     public void testCreateVmRequiresPermission() throws Exception {
         // Revoke the MANAGE_VIRTUAL_MACHINE permission for the test app
@@ -349,6 +357,41 @@ public class MicrodroidTestCase extends VirtualizationTestCaseBase {
         shutdownMicrodroid(getDevice(), cid);
     }
 
+    @Test
+    public void testTombstonesAreBeingForwarded() throws Exception {
+        // Note this test relies on logcat values being printed by tombstone_transmit on
+        // and the reeceiver on host (virtualization_service)
+        final String configPath = "assets/vm_config.json"; // path inside the APK
+        final String cid =
+                startMicrodroid(
+                        getDevice(),
+                        getBuild(),
+                        APK_NAME,
+                        PACKAGE_NAME,
+                        configPath,
+                        /* debug */ true,
+                        minMemorySize(),
+                        Optional.of(NUM_VCPUS),
+                        Optional.of(CPU_AFFINITY));
+        adbConnectToMicrodroid(getDevice(), cid);
+        waitForLogdInit();
+        runOnMicrodroid("logcat -c");
+        // We need root permission to write to /data/tombstones/
+        rootMicrodroid();
+        // Write a test tombstone file in /data/tombstones
+        runOnMicrodroid("echo -n \'Test tombstone in VM with 34 bytes\'"
+                    + "> /data/tombstones/transmit.txt");
+        // check if the tombstone have been tranferred from VM
+        assertNotEquals(runOnMicrodroid("timeout 15s logcat | grep -m 1 "
+                            + "'tombstone_transmit.microdroid:.*data/tombstones/transmit.txt'"),
+                "");
+        // Confirm that tombstone is received (from host logcat)
+        assertNotEquals(runOnHost("adb", "-s", getDevice().getSerialNumber(),
+                            "logcat", "-d", "-e",
+                            "Received 34 bytes from guest & wrote to tombstone file.*"),
+                "");
+    }
+
     @Test
     public void testMicrodroidBoots() throws Exception {
         final String configPath = "assets/vm_config.json"; // path inside the APK
@@ -364,12 +407,7 @@ public class MicrodroidTestCase extends VirtualizationTestCaseBase {
                         Optional.of(NUM_VCPUS),
                         Optional.of(CPU_AFFINITY));
         adbConnectToMicrodroid(getDevice(), cid);
-
-        // Wait until logd-init starts. The service is one of the last services that are started in
-        // the microdroid boot procedure. Therefore, waiting for the service means that we wait for
-        // the boot to complete. TODO: we need a better marker eventually.
-        tryRunOnMicrodroid("watch -e \"getprop init.svc.logd-reinit | grep '^$'\"");
-
+        waitForLogdInit();
         // Test writing to /data partition
         runOnMicrodroid("echo MicrodroidTest > /data/local/tmp/test.txt");
         assertThat(runOnMicrodroid("cat /data/local/tmp/test.txt"), is("MicrodroidTest"));

virtualizationservice/Android.bp

@@ -45,6 +45,7 @@ rust_defaults {
         "libserde_xml_rs",
         "libshared_child",
         "libstatslog_virtualization_rust",
+        "libtombstoned_client_rust",
         "libvmconfig",
         "libzip",
         "libvsock",

virtualizationservice/aidl/android/system/virtualmachineservice/IVirtualMachineService.aidl

@@ -29,6 +29,12 @@ interface IVirtualMachineService {
      */
     const int VM_BINDER_SERVICE_PORT = 5000;
 
+    /**
+     * Port number that VirtualMachineService listens on connections from the guest VMs for the
+     * tombtones
+     */
+    const int VM_TOMBSTONES_SERVICE_PORT = 2000;
+
     /**
      * Notifies that the payload has started.
      */

virtualizationservice/src/aidl.rs

@@ -42,7 +42,7 @@ use android_system_virtualizationservice::binder::{
 use android_system_virtualmachineservice::aidl::android::system::virtualmachineservice::{
     IVirtualMachineService::{
         BnVirtualMachineService, IVirtualMachineService, VM_BINDER_SERVICE_PORT,
-        VM_STREAM_SERVICE_PORT,
+        VM_STREAM_SERVICE_PORT, VM_TOMBSTONES_SERVICE_PORT,
     },
 };
 use anyhow::{anyhow, bail, Context, Result};
@@ -57,13 +57,14 @@ use statslog_virtualization_rust::vm_creation_requested::{stats_write, Hyperviso
 use std::convert::TryInto;
 use std::ffi::CStr;
 use std::fs::{create_dir, File, OpenOptions};
-use std::io::{Error, ErrorKind, Write};
+use std::io::{Error, ErrorKind, Write, Read};
 use std::num::NonZeroU32;
 use std::os::raw;
 use std::os::unix::io::{FromRawFd, IntoRawFd};
 use std::path::{Path, PathBuf};
 use std::ptr::null_mut;
 use std::sync::{Arc, Mutex, Weak};
+use tombstoned_client::{TombstonedConnection, DebuggerdDumpType};
 use vmconfig::VmConfig;
 use vsock::{SockAddr, VsockListener, VsockStream};
 use zip::ZipArchive;
@@ -86,6 +87,8 @@ const ANDROID_VM_INSTANCE_MAGIC: &str = "Android-VM-instance";
 /// Version of the instance image format
 const ANDROID_VM_INSTANCE_VERSION: u16 = 1;
 
+const CHUNK_RECV_MAX_LEN: usize = 1024;
+
 /// Implementation of `IVirtualizationService`, the entry point of the AIDL service.
 #[derive(Debug, Default)]
 pub struct VirtualizationService {
@@ -371,6 +374,55 @@ impl IVirtualizationService for VirtualizationService {
     }
 }
 
+fn handle_stream_connection_tombstoned() -> Result<()> {
+    let listener =
+        VsockListener::bind_with_cid_port(VMADDR_CID_HOST, VM_TOMBSTONES_SERVICE_PORT as u32)?;
+    info!("Listening to tombstones from guests ...");
+    for incoming_stream in listener.incoming() {
+        let mut incoming_stream = match incoming_stream {
+            Err(e) => {
+                warn!("invalid incoming connection: {}", e);
+                continue;
+            }
+            Ok(s) => s,
+        };
+        std::thread::spawn(move || {
+            if let Err(e) = handle_tombstone(&mut incoming_stream) {
+                error!("Failed to write tombstone- {:?}", e);
+            }
+        });
+    }
+    Ok(())
+}
+
+fn handle_tombstone(stream: &mut VsockStream) -> Result<()> {
+    if let Ok(SockAddr::Vsock(addr)) = stream.peer_addr() {
+        info!("Vsock Stream connected to cid={} for tombstones", addr.cid());
+    }
+    let tb_connection =
+        TombstonedConnection::connect(std::process::id() as i32, DebuggerdDumpType::Tombstone)
+            .context("Failed to connect to tombstoned")?;
+    let mut text_output = tb_connection
+        .text_output
+        .as_ref()
+        .ok_or_else(|| anyhow!("Could not get file to write the tombstones on"))?;
+    let mut num_bytes_read = 0;
+    loop {
+        let mut chunk_recv = [0; CHUNK_RECV_MAX_LEN];
+        let n = stream
+            .read(&mut chunk_recv)
+            .context("Failed to read tombstone data from Vsock stream")?;
+        if n == 0 {
+            break;
+        }
+        num_bytes_read += n;
+        text_output.write_all(&chunk_recv[0..n]).context("Failed to write guests tombstones")?;
+    }
+    info!("Received {} bytes from guest & wrote to tombstone file", num_bytes_read);
+    tb_connection.notify_completion()?;
+    Ok(())
+}
+
 impl VirtualizationService {
     pub fn init() -> VirtualizationService {
         let service = VirtualizationService::default();
@@ -381,8 +433,15 @@ impl VirtualizationService {
             handle_stream_connection_from_vm(state).unwrap();
         });
 
+        std::thread::spawn(|| {
+            if let Err(e) = handle_stream_connection_tombstoned() {
+                warn!("Error receiving tombstone from guest or writing them. Error: {}", e);
+            }
+        });
+
         // binder server for vm
-        let mut state = service.state.clone(); // reference to state (not the state itself) is copied
+        // reference to state (not the state itself) is copied
+        let mut state = service.state.clone();
         std::thread::spawn(move || {
             let state_ptr = &mut state as *mut _ as *mut raw::c_void;