Try to load native linux libraries with matching classifier first (#9411)

Motivation:

Users' runtime systems may have incompatible dynamic libraries to the ones our
tcnative wrappers link to. Unfortunately, we cannot determine and catch these
scenarios (in which the JVM crashes) but we can make a more educated guess on
what library to load and try to find one that works better before crashing.

Modifications:

1) Build dynamically linked openSSL builds for more OSs (netty-tcnative)
2) Load native linux libraries with matching classifier (first)

Result:

More developers / users can use the dynamically-linked native libraries.

common/src/main/java/io/netty/util/internal/PlatformDependent.java

@@ -15,6 +15,7 @@
  */
 package io.netty.util.internal;
 
+import io.netty.util.CharsetUtil;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 import org.jctools.queues.MpscArrayQueue;
@@ -28,19 +29,28 @@ import org.jctools.queues.atomic.SpscLinkedAtomicQueue;
 import org.jctools.util.Pow2;
 import org.jctools.util.UnsafeAccess;
 
+import java.io.BufferedReader;
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.Deque;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Queue;
 import java.util.Random;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentLinkedDeque;
 import java.util.concurrent.ConcurrentMap;
@@ -97,6 +107,10 @@ public final class PlatformDependent {
     private static final String NORMALIZED_ARCH = normalizeArch(SystemPropertyUtil.get("os.arch", ""));
     private static final String NORMALIZED_OS = normalizeOs(SystemPropertyUtil.get("os.name", ""));
 
+    // keep in sync with maven's pom.xml via os.detection.classifierWithLikes!
+    private static final String[] ALLOWED_LINUX_OS_CLASSIFIERS = {"fedora", "suse", "arch"};
+    private static final Set<String> LINUX_OS_CLASSIFIERS;
+
     private static final int ADDRESS_SIZE = addressSize0();
     private static final boolean USE_DIRECT_BUFFER_NO_CLEANER;
     private static final AtomicLong DIRECT_MEMORY_COUNTER;
@@ -196,6 +210,50 @@ public final class PlatformDependent {
                     "Unless explicitly requested, heap buffer will always be preferred to avoid potential system " +
                     "instability.");
         }
+
+        // For specifications, see https://www.freedesktop.org/software/systemd/man/os-release.html
+        final String[] OS_RELEASE_FILES = {"/etc/os-release", "/usr/lib/os-release"};
+        final String LINUX_ID_PREFIX = "ID=";
+        final String LINUX_ID_LIKE_PREFIX = "ID_LIKE=";
+        Set<String> allowedClassifiers = new HashSet<String>(Arrays.asList(ALLOWED_LINUX_OS_CLASSIFIERS));
+        allowedClassifiers = Collections.unmodifiableSet(allowedClassifiers);
+        Set<String> availableClassifiers = new LinkedHashSet<String>();
+
+        for (String osReleaseFileName : OS_RELEASE_FILES) {
+            final File file = new File(osReleaseFileName);
+            if (file.exists()) {
+                BufferedReader reader = null;
+                try {
+                    reader = new BufferedReader(
+                            new InputStreamReader(
+                                    new FileInputStream(file), CharsetUtil.UTF_8));
+
+                    String line;
+                    while ((line = reader.readLine()) != null) {
+                        if (line.startsWith(LINUX_ID_PREFIX)) {
+                            String id = normalizeOsReleaseVariableValue(line.substring(LINUX_ID_PREFIX.length()));
+                            addClassifier(allowedClassifiers, availableClassifiers, id);
+                        } else if (line.startsWith(LINUX_ID_LIKE_PREFIX)) {
+                            line = normalizeOsReleaseVariableValue(line.substring(LINUX_ID_LIKE_PREFIX.length()));
+                            addClassifier(allowedClassifiers, availableClassifiers, line.split("[ ]+"));
+                        }
+                    }
+                } catch (IOException ignored) {
+                    // Ignore
+                } finally {
+                    if (reader != null) {
+                        try {
+                            reader.close();
+                        } catch (IOException ignored) {
+                            // Ignore
+                        }
+                    }
+                }
+                // specification states we should only fall back if /etc/os-release does not exist
+                break;
+            }
+        }
+        LINUX_OS_CLASSIFIERS = Collections.unmodifiableSet(availableClassifiers);
     }
 
     public static boolean hasDirectBufferNoCleanerConstructor() {
@@ -1274,6 +1332,30 @@ public final class PlatformDependent {
         return NORMALIZED_OS;
     }
 
+    public static Set<String> normalizedLinuxClassifiers() {
+        return LINUX_OS_CLASSIFIERS;
+    }
+
+    /**
+     * Adds only those classifier strings to <tt>dest</tt> which are present in <tt>allowed</tt>.
+     *
+     * @param allowed          allowed classifiers
+     * @param dest             destination set
+     * @param maybeClassifiers potential classifiers to add
+     */
+    private static void addClassifier(Set<String> allowed, Set<String> dest, String... maybeClassifiers) {
+        for (String id : maybeClassifiers) {
+            if (allowed.contains(id)) {
+                dest.add(id);
+            }
+        }
+    }
+
+    private static String normalizeOsReleaseVariableValue(String value) {
+        // Variable assignment values may be enclosed in double or single quotes.
+        return value.trim().replaceAll("[\"']", "");
+    }
+
     private static String normalize(String value) {
         return value.toLowerCase(Locale.US).replaceAll("[^a-z0-9]+", "");
     }

handler/src/main/java/io/netty/handler/ssl/OpenSsl.java

@@ -552,15 +552,25 @@ public final class OpenSsl {
         String os = PlatformDependent.normalizedOs();
         String arch = PlatformDependent.normalizedArch();
 
-        Set<String> libNames = new LinkedHashSet<String>(4);
+        Set<String> libNames = new LinkedHashSet<String>(5);
         String staticLibName = "netty_tcnative";
 
         // First, try loading the platform-specific library. Platform-specific
         // libraries will be available if using a tcnative uber jar.
-        libNames.add(staticLibName + "_" + os + '_' + arch);
         if ("linux".equalsIgnoreCase(os)) {
-            // Fedora SSL lib so naming (libssl.so.10 vs libssl.so.1.0.0)..
+            Set<String> classifiers = PlatformDependent.normalizedLinuxClassifiers();
+            for (String classifier : classifiers) {
+                libNames.add(staticLibName + "_" + os + '_' + arch + "_" + classifier);
+            }
+            // generic arch-dependent library
+            libNames.add(staticLibName + "_" + os + '_' + arch);
+
+            // Fedora SSL lib so naming (libssl.so.10 vs libssl.so.1.0.0).
+            // note: should already be included from the classifiers but if not, we use this as an
+            //       additional fallback option here
             libNames.add(staticLibName + "_" + os + '_' + arch + "_fedora");
+        } else {
+            libNames.add(staticLibName + "_" + os + '_' + arch);
         }
         libNames.add(staticLibName + "_" + arch);
         libNames.add(staticLibName);

pom.xml

@@ -296,8 +296,9 @@
     <argLine.javaProperties>-D_</argLine.javaProperties>
     <!-- Configure the os-maven-plugin extension to expand the classifier on                  -->
     <!-- Fedora-"like" systems. This is currently only used for the netty-tcnative dependency -->
-    <os.detection.classifierWithLikes>fedora</os.detection.classifierWithLikes>
     <osmaven.version>1.6.2</osmaven.version>
+    <!-- keep in sync with PlatformDependent#ALLOWED_LINUX_OS_CLASSIFIERS -->
+    <os.detection.classifierWithLikes>fedora,suse,arch</os.detection.classifierWithLikes>
     <tcnative.artifactId>netty-tcnative</tcnative.artifactId>
     <tcnative.version>2.0.25.Final</tcnative.version>
     <tcnative.classifier>${os.detected.classifier}</tcnative.classifier>