From 6ad888c42ad5105a3e35aa2c39aca8351b7b73cb Mon Sep 17 00:00:00 2001
From: Dmitry Muhomor <muhomor.dmitry@gmail.com>
Date: Sun, 29 Oct 2023 15:06:14 +0200
Subject: [PATCH] memtag_test: improve capturing of test results

Using debuggerd + logcat parsing is unreliable and slow, print SEGV signal code to stderr instead.
---
 androidtest/memtag/memtag_test.cc             | 13 ++++
 .../src/grapheneos/hmalloc/MemtagTest.java    | 71 ++++---------------
 2 files changed, 28 insertions(+), 56 deletions(-)

diff --git a/androidtest/memtag/memtag_test.cc b/androidtest/memtag/memtag_test.cc
index db48afa..e6ec68d 100644
--- a/androidtest/memtag/memtag_test.cc
+++ b/androidtest/memtag/memtag_test.cc
@@ -2,6 +2,7 @@
 #undef NDEBUG
 #include <assert.h>
 #include <malloc.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -249,6 +250,11 @@ map<string, function<void()>> tests = {
 #undef TEST
 };
 
+void segv_handler(int, siginfo_t *si, void *) {
+    fprintf(stderr, "SEGV_CODE %i", si->si_code);
+    exit(139); // standard exit code for SIGSEGV
+}
+
 int main(int argc, char **argv) {
     setbuf(stdout, NULL);
     assert(argc == 2);
@@ -259,6 +265,13 @@ int main(int argc, char **argv) {
 
     assert(mallopt(M_BIONIC_SET_HEAP_TAGGING_LEVEL, M_HEAP_TAGGING_LEVEL_ASYNC) == 1);
 
+    struct sigaction sa = {
+        .sa_sigaction = segv_handler,
+        .sa_flags = SA_SIGINFO,
+    };
+
+    assert(sigaction(SIGSEGV, &sa, nullptr) == 0);
+
     test_fn();
     do_context_switch();
     
diff --git a/androidtest/src/grapheneos/hmalloc/MemtagTest.java b/androidtest/src/grapheneos/hmalloc/MemtagTest.java
index 5544128..8cb7a45 100644
--- a/androidtest/src/grapheneos/hmalloc/MemtagTest.java
+++ b/androidtest/src/grapheneos/hmalloc/MemtagTest.java
@@ -19,10 +19,19 @@ public class MemtagTest extends BaseHostJUnit4Test {
     private static final String TEST_BINARY = "/data/local/tmp/memtag_test";
 
     enum Result {
-        SUCCESS,
+        SUCCESS(0, ""),
         // it's expected that the device is configured to use asymm MTE tag checking mode
-        ASYNC_MTE_ERROR,
-        SYNC_MTE_ERROR,
+        ASYNC_MTE_ERROR(139, "SEGV_CODE 8"),
+        SYNC_MTE_ERROR(139, "SEGV_CODE 9"),
+        ;
+
+        public final int exitCode;
+        public final String stderr;
+
+        Result(int exitCode, String stderr) {
+            this.exitCode = exitCode;
+            this.stderr = stderr;
+        }
     }
 
     private static final int SEGV_EXIT_CODE = 139;
@@ -31,62 +40,12 @@ public class MemtagTest extends BaseHostJUnit4Test {
         var args = new ArrayList<String>();
         args.add(TEST_BINARY);
         args.add(name);
-        var device = getDevice();
-        long deviceDate = device.getDeviceDate();
         String cmdLine = String.join(" ", args);
-        var result = device.executeShellV2Command(cmdLine);
 
-        int expectedExitCode = expectedResult == Result.SUCCESS ? 0 : SEGV_EXIT_CODE;
+        var result = getDevice().executeShellV2Command(cmdLine);
 
-        assertEquals("process exit code", expectedExitCode, result.getExitCode().intValue());
-
-        if (expectedResult == Result.SUCCESS) {
-            return;
-        }
-
-        try {
-            // wait a bit for debuggerd to capture the crash
-            Thread.sleep(50);
-        } catch (InterruptedException e) {
-            throw new IllegalStateException(e);
-        }
-
-        try (var logcat = device.getLogcatSince(deviceDate)) {
-            try (var s = logcat.createInputStream()) {
-                String[] lines = new String(s.readAllBytes()).split("\n");
-                boolean foundCmd = false;
-                String cmd = "Cmdline: " + cmdLine;
-                String expectedSignalCode = switch (expectedResult) {
-                    case ASYNC_MTE_ERROR -> "SEGV_MTEAERR";
-                    case SYNC_MTE_ERROR -> "SEGV_MTESERR";
-                    default -> throw new IllegalStateException(expectedResult.name());
-                };
-                for (String line : lines) {
-                    if (!foundCmd) {
-                        if (line.contains(cmd)) {
-                            foundCmd = true;
-                        }
-                        continue;
-                    }
-
-                    if (line.contains("signal 11 (SIGSEGV), code")) {
-                        if (!line.contains(expectedSignalCode)) {
-                            break;
-                        } else {
-                            return;
-                        }
-                    }
-
-                    if (line.contains("backtrace")) {
-                        break;
-                    }
-                }
-
-                fail("missing " + expectedSignalCode + " crash in logcat");
-            } catch (IOException e) {
-                throw new IllegalStateException(e);
-            }
-        }
+        assertEquals("process exit code", expectedResult.exitCode, result.getExitCode().intValue());
+        assertEquals("stderr", expectedResult.stderr, result.getStderr());
     }
 
     @Test