[GR-30397] Remove usages of signal() and sigset().

PullRequest: graal/9613

Author: peter-hofer

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/PosixSubstrateSegfaultHandler.java

@@ -102,7 +102,7 @@ protected void install() {
         /* Register sa_sigaction signal handler */
         structSigAction.sa_flags(Signal.SA_SIGINFO() | Signal.SA_NODEFER());
         structSigAction.sa_sigaction(advancedSignalDispatcher.getFunctionPointer());
-        Signal.sigaction(Signal.SignalEnum.SIGSEGV, structSigAction, WordFactory.nullPointer());
-        Signal.sigaction(Signal.SignalEnum.SIGBUS, structSigAction, WordFactory.nullPointer());
+        Signal.sigaction(Signal.SignalEnum.SIGSEGV.getCValue(), structSigAction, WordFactory.nullPointer());
+        Signal.sigaction(Signal.SignalEnum.SIGBUS.getCValue(), structSigAction, WordFactory.nullPointer());
     }
 }

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/PosixUtils.java

@@ -28,8 +28,6 @@
 import java.io.IOException;
 import java.util.function.Function;
 
-import com.oracle.svm.core.posix.linux.libc.GLibC;
-import com.oracle.svm.core.c.libc.LibCBase;
 import org.graalvm.compiler.serviceprovider.JavaVersionUtil;
 import org.graalvm.nativeimage.ImageSingletons;
 import org.graalvm.nativeimage.Platform;
@@ -49,11 +47,14 @@
 import com.oracle.svm.core.annotate.Alias;
 import com.oracle.svm.core.annotate.TargetClass;
 import com.oracle.svm.core.annotate.Uninterruptible;
+import com.oracle.svm.core.c.libc.LibCBase;
 import com.oracle.svm.core.posix.headers.Dlfcn;
 import com.oracle.svm.core.posix.headers.Errno;
 import com.oracle.svm.core.posix.headers.Locale;
+import com.oracle.svm.core.posix.headers.Signal;
 import com.oracle.svm.core.posix.headers.Unistd;
 import com.oracle.svm.core.posix.headers.Wait;
+import com.oracle.svm.core.posix.linux.libc.GLibC;
 import com.oracle.svm.core.util.VMError;
 
 public class PosixUtils {
@@ -259,4 +260,24 @@ public static int readBytes(int fd, CCharPointer buffer, int bufferLen, int read
         }
         return readBytes;
     }
+
+    /**
+     * Emulates the deprecated {@code signal} function via its replacement {@code sigaction},
+     * assuming BSD semantics (like glibc does, for example).
+     *
+     * Use this or {@code sigaction} directly instead of calling {@code signal} or {@code sigset}:
+     * they are not portable and when running in HotSpot, signal chaining (libjsig) prints warnings.
+     */
+    public static Signal.SignalDispatcher installSignalHandler(int signum, Signal.SignalDispatcher handler) {
+        Signal.sigaction old = StackValue.get(Signal.sigaction.class);
+        Signal.sigaction act = StackValue.get(Signal.sigaction.class);
+        Signal.sigemptyset(act.sa_mask());
+        Signal.sigaddset(act.sa_mask(), signum);
+        act.sa_flags(Signal.SA_RESTART());
+        act.sa_handler(handler);
+        if (Signal.sigaction(signum, act, old) != 0) {
+            return Signal.SIG_ERR();
+        }
+        return old.sa_handler();
+    }
 }

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/SunMiscSubstitutions.java

@@ -135,20 +135,19 @@ private Util_jdk_internal_misc_Signal() {
      * This implementation does not complain (by returning -1) about registering signal handlers for
      * signals that the VM itself uses.
      */
-    protected static long handle0(int sig, long nativeH) {
+    static long handle0(int sig, long nativeH) {
         ensureInitialized();
         final Signal.SignalDispatcher newDispatcher = nativeHToDispatcher(nativeH);
         /* If the dispatcher is the CSunMiscSignal handler, then check if the signal is in range. */
         if ((newDispatcher == CSunMiscSignal.countingHandlerFunctionPointer()) && (CSunMiscSignal.signalRangeCheck(sig) != 1)) {
             return sunMiscSignalErrorHandler;
         }
         updateDispatcher(sig, newDispatcher);
-        final Signal.SignalDispatcher oldDispatcher = Signal.signal(sig, newDispatcher);
+        final Signal.SignalDispatcher oldDispatcher = PosixUtils.installSignalHandler(sig, newDispatcher);
         CIntPointer sigset = StackValue.get(CIntPointer.class);
         sigset.write(1 << (sig - 1));
         Signal.sigprocmask(Signal.SIG_UNBLOCK(), (Signal.sigset_tPointer) sigset, WordFactory.nullPointer());
-        final long result = dispatcherToNativeH(oldDispatcher);
-        return result;
+        return dispatcherToNativeH(oldDispatcher);
     }
 
     /** Runtime initialization. */
@@ -409,7 +408,7 @@ final class IgnoreSIGPIPEStartupHook implements Runnable {
      */
     @Override
     public void run() {
-        final SignalDispatcher signalResult = Signal.signal(Signal.SignalEnum.SIGPIPE.getCValue(), Signal.SIG_IGN());
+        final SignalDispatcher signalResult = PosixUtils.installSignalHandler(Signal.SignalEnum.SIGPIPE.getCValue(), Signal.SIG_IGN());
         VMError.guarantee(signalResult != Signal.SIG_ERR(), "IgnoreSIGPIPEFeature.run: Could not ignore SIGPIPE");
     }
 }

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/headers/Signal.java

@@ -44,6 +44,7 @@
 
 import com.oracle.svm.core.RegisterDumper;
 import com.oracle.svm.core.SubstrateSegfaultHandler;
+import com.oracle.svm.core.posix.PosixUtils;
 
 // Checkstyle: stop
 
@@ -72,14 +73,16 @@ public class Signal {
     public interface sigset_tPointer extends PointerBase {
     }
 
+    /**
+     * Warning: use {@link #sigaction} or {@link PosixUtils#installSignalHandler}. Do NOT introduce
+     * calls to {@code signal} or {@code sigset}, which are not portable, and when running in
+     * HotSpot, signal chaining (libjsig) will print warnings.
+     */
     public interface SignalDispatcher extends CFunctionPointer {
         @InvokeCFunctionPointer
         void dispatch(int sig);
     }
 
-    @CFunction
-    public static native SignalDispatcher signal(int signum, SignalDispatcher handler);
-
     @CConstant
     public static native SignalDispatcher SIG_DFL();
 
@@ -288,6 +291,9 @@ public interface AdvancedSignalDispatcher extends CFunctionPointer {
         void dispatch(int signum, siginfo_t siginfo, WordPointer opaque);
     }
 
+    @CConstant
+    public static native int SA_RESTART();
+
     @CConstant
     public static native int SA_SIGINFO();
 
@@ -318,8 +324,9 @@ public interface sigaction extends PointerBase {
         sigset_tPointer sa_mask();
     }
 
+    /** @param signum from {@link SignalEnum#getCValue()} */
     @CFunction
-    public static native int sigaction(SignalEnum signum, sigaction act, sigaction oldact);
+    public static native int sigaction(int signum, sigaction act, sigaction oldact);
 
     @CEnum
     @CContext(PosixDirectives.class)
@@ -383,4 +390,7 @@ public enum DarwinSignalEnum {
 
     @CFunction
     public static native int sigemptyset(sigset_tPointer set);
+
+    @CFunction
+    public static native int sigaddset(sigset_tPointer set, int signum);
 }