Add an abort handler and preload it on Linux (#1456)

Some native code (CEF) may cause SIGTRAP to be sent on fatal errors,
which brings down the entire server. Instead only kill the thread and
attempt to continue.

.gitignore

@@ -20,3 +20,4 @@ scripts/OpenJDK*
 scripts/zulu*
 scripts/electron-*
 scripts/rcedit-*
+scripts/resources/*.so

scripts/bundler.sh

@@ -38,6 +38,10 @@ main() {
 
   download_launcher
 
+  if [ ! -f scripts/resources/catch_abort.so ]; then
+    gcc -fPIC -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -shared scripts/resources/catch_abort.c -lpthread -o scripts/resources/catch_abort.so
+  fi
+
   case "$OS" in
     debian-all)
       RELEASE="$RELEASE_NAME.deb"
@@ -184,6 +188,7 @@ make_linux_bundle() {
   cp "$JAR" "$RELEASE_NAME/bin/Suwayomi-Server.jar"
   cp "scripts/resources/suwayomi-launcher.sh" "$RELEASE_NAME/"
   cp "scripts/resources/suwayomi-server.sh" "$RELEASE_NAME/"
+  cp "scripts/resources/catch_abort.so" "$RELEASE_NAME/bin/"
 
   tar -I "gzip -9" -cvf "$RELEASE" "$RELEASE_NAME/"
 }
@@ -208,6 +213,7 @@ make_deb_package() {
   mv "$RELEASE_NAME/Suwayomi-Launcher.jar" "$RELEASE_NAME/$source_dir/Suwayomi-Launcher.jar"
   cp "$JAR" "$RELEASE_NAME/$source_dir/Suwayomi-Server.jar"
   copy_linux_package_assets_to "$RELEASE_NAME/$source_dir/"
+  cp "scripts/resources/catch_abort.so" "$RELEASE_NAME/$source_dir/"
   tar -I "gzip" -C "$RELEASE_NAME/" -cvf "$upstream_source" "$source_dir"
 
   cp -r "scripts/resources/deb/" "$RELEASE_NAME/$source_dir/debian/"

scripts/resources/catch_abort.c

@@ -0,0 +1,62 @@
+// Linux only:
+// Attempts to catch SIGTRAP, inform Java, then exit the thread instead of bringing down the whole process
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <signal.h>
+#include <pthread.h>
+#include <execinfo.h>
+
+#include <jni.h>
+
+JavaVM *g_vm;
+
+void load_vm() {
+  if (g_vm) return;
+  JavaVM *vms[1];
+  jsize n = 0;
+  // JNI_OnLoad won't be called when loaded via LD_PRELOAD, so attempt to find the VM now
+  if (JNI_GetCreatedJavaVMs(vms, 1, &n) == JNI_OK && n > 0) {
+    g_vm = vms[0];
+  }
+}
+
+jint throwThreadDeath(JNIEnv *env, char *message) {
+  char *className = "java/lang/UnknownError";
+  jclass exClass = (*env)->FindClass(env, className);
+  if (exClass == NULL) return JNI_ERR;
+  return (*env)->ThrowNew(env, exClass, message);
+}
+
+void signalHandler(int signum, siginfo_t* si, void* uc) {
+  void *retaddrs[64];
+  int n = backtrace(retaddrs, sizeof(retaddrs) / sizeof(retaddrs[0]));
+  printf("\n### ABORT :: Backtrace: ###\n");
+  backtrace_symbols_fd(retaddrs, n, STDERR_FILENO);
+  printf("### ABORT :: Exiting this thread. If this causes problems, please report the above backtrace to Suwayomi. ###\n\n");
+
+  load_vm();
+  if (g_vm) {
+    JNIEnv *env;
+    jint getEnvStat = (*g_vm)->GetEnv(g_vm, (void**) &env, JNI_VERSION_1_2);
+    if (getEnvStat == JNI_EDETACHED) (*g_vm)->AttachCurrentThread(g_vm, (void**) &env, NULL);
+    jint exStat = throwThreadDeath(env, "SIGTRAP caught");
+    if (exStat != 0) printf("Exception throwing failed: %d\n", exStat);
+    (*g_vm)->DetachCurrentThread(g_vm);
+  }
+  pthread_exit(NULL);
+}
+
+__attribute__((constructor))
+void dlmain() {
+  struct sigaction sa = {0};
+  sa.sa_flags     = SA_SIGINFO | SA_RESTART;
+  sa.sa_sigaction = &signalHandler;
+  sigemptyset(&sa.sa_mask);
+  if (sigaction(SIGTRAP, &sa, NULL) != 0) {
+    printf("[FATAL] sigaction failed\n");
+  }
+}

scripts/resources/deb/install

@@ -11,3 +11,4 @@ suwayomi-server.tmpfiles => usr/lib/tmpfiles.d/suwayomi-server.conf
 suwayomi-server.conf     => etc/suwayomi/server.conf
 suwayomi-server.sh       => usr/bin/suwayomi-server
 suwayomi-launcher.sh     => usr/bin/suwayomi-launcher
+catch_abort.so              usr/share/java/suwayomi-server/bin/

scripts/resources/pkg/suwayomi-server.sh

@@ -1,3 +1,4 @@
 #!/bin/sh
 
+export LD_PRELOAD="/usr/share/java/suwayomi-server/bin/catch_abort.so"
 exec /usr/bin/java -jar /usr/share/java/suwayomi-server/bin/Suwayomi-Server.jar

scripts/resources/suwayomi-server.sh

@@ -1,3 +1,4 @@
 #!/bin/sh
 
+export LD_PRELOAD="`realpath ./bin/catch_abort.so`"
 exec ./jre/bin/java -jar ./bin/Suwayomi-Server.jar