[GR-67169] Support JFR emergency dumps on out of memory

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

@@ -24,6 +24,8 @@
  */
 package com.oracle.svm.core.posix;
 
+import static com.oracle.svm.core.Uninterruptible.CALLED_FROM_UNINTERRUPTIBLE_CODE;
+
 import org.graalvm.nativeimage.c.type.CCharPointer;
 import org.graalvm.nativeimage.c.type.CCharPointerPointer;
 import org.graalvm.word.PointerBase;
@@ -107,6 +109,12 @@ public int strcmp(CCharPointer s1, CCharPointer s2) {
         return PosixLibC.strcmp(s1, s2);
     }
 
+    @Override
+    @Uninterruptible(reason = CALLED_FROM_UNINTERRUPTIBLE_CODE, mayBeInlined = true)
+    public int strncmp(CCharPointer s1, CCharPointer s2, UnsignedWord n) {
+        return PosixLibC.strncmp(s1, s2, n);
+    }
+
     @Override
     @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
     public int isdigit(int c) {

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

@@ -38,10 +38,11 @@ public final class PosixPlatformTimeUtils extends PlatformTimeUtils {
     @Override
     @BasedOnJDKFile("https://github.com/openjdk/jdk/blob/jdk-24+3/src/hotspot/os/posix/os_posix.cpp#L1409-L1415")
     @Uninterruptible(reason = "Must not migrate platform threads when executing on a virtual thread.")
-    public SecondsNanos javaTimeSystemUTC() {
+    public void javaTimeSystemUTC(SecondsNanos result) {
         Time.timespec ts = StackValue.get(Time.timespec.class);
         int status = PosixUtils.clock_gettime(Time.CLOCK_REALTIME(), ts);
         PosixUtils.checkStatusIs0(status, "javaTimeSystemUTC: clock_gettime(CLOCK_REALTIME) failed.");
-        return allocateSecondsNanosInterruptibly(ts.tv_sec(), ts.tv_nsec());
+        result.setNanos(ts.tv_nsec());
+        result.setSeconds(ts.tv_sec());
     }
 }

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

@@ -26,6 +26,8 @@
 
 import static org.graalvm.nativeimage.c.function.CFunction.Transition.NO_TRANSITION;
 
+import com.oracle.svm.core.Uninterruptible;
+import com.oracle.svm.core.headers.LibC;
 import org.graalvm.nativeimage.c.CContext;
 import org.graalvm.nativeimage.c.constant.CConstant;
 import org.graalvm.nativeimage.c.function.CFunction;
@@ -74,5 +76,15 @@ public static class NoTransitions {
         @CFunction(transition = NO_TRANSITION)
         public static native int unlinkat(int dirfd, CCharPointer pathname, int flags);
 
+        @Uninterruptible(reason = "LibC.errno() must not be overwritten accidentally.")
+        public static int restartableOpen(CCharPointer directory, int flags, int mode) {
+            int result;
+            do {
+                result = open(directory, flags, mode);
+            } while (result == -1 && LibC.errno() == Errno.EINTR());
+
+            return result;
+        }
+
     }
 }

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

@@ -77,6 +77,9 @@ public class PosixLibC {
     @CFunction(transition = CFunction.Transition.NO_TRANSITION)
     public static native int strcmp(PointerBase s1, PointerBase s2);
 
+    @CFunction(transition = CFunction.Transition.NO_TRANSITION)
+    public static native int strncmp(PointerBase s1, PointerBase s2, UnsignedWord n);
+
     @CFunction(transition = CFunction.Transition.NO_TRANSITION)
     public static native CCharPointer strcpy(CCharPointer dst, CCharPointer src);
 

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/jdk/Target_jdk_internal_misc_VM.java

@@ -29,6 +29,7 @@
 
 import com.oracle.svm.core.annotate.Substitute;
 import com.oracle.svm.core.annotate.TargetClass;
+import com.oracle.svm.core.graal.stackvalue.UnsafeStackValue;
 import com.oracle.svm.core.util.BasedOnJDKFile;
 import com.oracle.svm.core.util.PlatformTimeUtils;
 import com.oracle.svm.core.util.PlatformTimeUtils.SecondsNanos;
@@ -41,13 +42,13 @@ final class Target_jdk_internal_misc_VM {
     public static long getNanoTimeAdjustment(long offsetInSeconds) {
         long maxDiffSecs = 0x0100000000L;
         long minDiffSecs = -maxDiffSecs;
+        SecondsNanos time = UnsafeStackValue.get(SecondsNanos.class);
+        PlatformTimeUtils.singleton().javaTimeSystemUTC(time);
 
-        SecondsNanos time = PlatformTimeUtils.singleton().javaTimeSystemUTC();
-
-        long diff = time.seconds() - offsetInSeconds;
+        long diff = time.getSeconds() - offsetInSeconds;
         if (diff >= maxDiffSecs || diff <= minDiffSecs) {
             return -1;
         }
-        return (diff * 1000000000) + time.nanos();
+        return (diff * 1000000000) + time.getNanos();
     }
 }