Adding test for loading JNI libraries in individual tests

Add a bivalent test that uses a native library.

Also added a utility method to load it in the same way on both
sides.

Bug: 318393625
Bug: 323931246

Test: run-ravenwood-tests.sh
Test: atest RavenwoodBivalentTest_device
Change-Id: I270058c15f718ff20640681742035e33e5e015a1

1 files changed, 127 insertions, 0 deletions

diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodUtils.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodUtils.java
new file mode 100644
index 000000000000..b736a7662bd4
--- /dev/null
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodUtils.java
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.platform.test.ravenwood;
+
+import java.io.File;
+import java.io.PrintStream;
+import java.util.Arrays;
+
+/**
+ * Utilities for writing (bivalent) ravenwood tests.
+ */
+public class RavenwoodUtils {
+    private RavenwoodUtils() {
+    }
+
+    /**
+     * Load a JNI library respecting {@code java.library.path}
+     * (which reflects {@code LD_LIBRARY_PATH}).
+     *
+     * <p>{@code libname} must be the library filename without:
+     * - directory
+     * - "lib" prefix
+     * - and the ".so" extension
+     *
+     * <p>For example, in order to load "libmyjni.so", then pass "myjni".
+     *
+     * <p>This is basically the same thing as Java's {@link System#loadLibrary(String)},
+     * but this API works slightly different on ART and on the desktop Java, namely
+     * the desktop Java version uses a different entry point method name
+     * {@code JNI_OnLoad_libname()} (note the included "libname")
+     * while ART always seems to use {@code JNI_OnLoad()}.
+     *
+     * <p>This method provides the same behavior on both the device side and on Ravenwood --
+     * it uses {@code JNI_OnLoad()} as the entry point name on both.
+     */
+    public static void loadJniLibrary(String libname) {
+        if (RavenwoodRule.isOnRavenwood()) {
+            loadLibraryOnRavenwood(libname);
+        } else {
+            // Just delegate to the loadLibrary().
+            System.loadLibrary(libname);
+        }
+    }
+
+    private static void loadLibraryOnRavenwood(String libname) {
+        var path = System.getProperty("java.library.path");
+        var filename = "lib" + libname + ".so";
+
+        System.out.println("Looking for library " + libname + ".so in java.library.path:" + path);
+
+        try {
+            if (path == null) {
+                throw new UnsatisfiedLinkError("Cannot load library " + libname + "."
+                        + " Property java.library.path not set!");
+            }
+            for (var dir : path.split(":")) {
+                var file = new File(dir + "/" + filename);
+                if (file.exists()) {
+                    System.load(file.getAbsolutePath());
+                    return;
+                }
+            }
+            throw new UnsatisfiedLinkError("Library " + libname + " no found in "
+                    + "java.library.path: " + path);
+        } catch (Exception e) {
+            dumpFiles(System.out);
+            throw e;
+        }
+    }
+
+    private static void dumpFiles(PrintStream out) {
+        try {
+            var path = System.getProperty("java.library.path");
+            out.println("# java.library.path=" + path);
+
+            for (var dir : path.split(":")) {
+                listFiles(out, new File(dir), "");
+
+                var gparent = new File((new File(dir)).getAbsolutePath() + "../../..")
+                        .getCanonicalFile();
+                if (gparent.getName().contains("testcases")) {
+                    // Special case: if we found this directory, dump its contents too.
+                    listFiles(out, gparent, "");
+                }
+            }
+        } catch (Throwable th) {
+            out.println("Error: " + th.toString());
+            th.printStackTrace(out);
+        }
+    }
+
+    private static void listFiles(PrintStream out, File dir, String prefix) {
+        if (!dir.isDirectory()) {
+            out.println(prefix + dir.getAbsolutePath() + " is not a directory!");
+            return;
+        }
+        out.println(prefix + ":" + dir.getAbsolutePath() + "/");
+        // First, list the files.
+        for (var file : Arrays.stream(dir.listFiles()).sorted().toList()) {
+            out.println(prefix + "  " + file.getName() + "" + (file.isDirectory() ? "/" : ""));
+        }
+
+        // Then recurse.
+        if (dir.getAbsolutePath().startsWith("/usr") || dir.getAbsolutePath().startsWith("/lib")) {
+            // There would be too many files, so don't recurse.
+            return;
+        }
+        for (var file : Arrays.stream(dir.listFiles()).sorted().toList()) {
+            if (file.isDirectory()) {
+                listFiles(out, file, prefix + "  ");
+            }
+        }
+    }
+}