Merge pull request #39 from cryptomator/feature/dont-resolve-null-poi…

…nters

Fix SIGSEV crashes by adding NULL pointer checks

jfuse-api/src/main/java/module-info.java

@@ -10,6 +10,7 @@
 
 	exports org.cryptomator.jfuse.api;
 	exports org.cryptomator.jfuse.api.platforms to org.cryptomator.jfuse.linux.aarch64, org.cryptomator.jfuse.linux.amd64, org.cryptomator.jfuse.mac, org.cryptomator.jfuse.win;
+	exports org.cryptomator.jfuse.api.util to org.cryptomator.jfuse.linux.aarch64, org.cryptomator.jfuse.linux.amd64, org.cryptomator.jfuse.mac, org.cryptomator.jfuse.win;
 
 	uses FuseBuilder;
 }

jfuse-api/src/main/java/org/cryptomator/jfuse/api/util/MemoryUtils.java

@@ -0,0 +1,18 @@
+package org.cryptomator.jfuse.api.util;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.foreign.MemorySegment;
+
+public class MemoryUtils {
+
+	@Nullable
+	public static String toUtf8StringOrNull(MemorySegment string, long offset) {
+		return MemorySegment.NULL.equals(string) ? null : string.getUtf8String(offset);
+	}
+
+	@Nullable
+	public static String toUtf8StringOrNull(MemorySegment string) {
+		return toUtf8StringOrNull(string, 0);
+	}
+}

jfuse-api/src/test/java/org/cryptomator/jfuse/api/util/MemoryUtilsTest.java

@@ -0,0 +1,41 @@
+package org.cryptomator.jfuse.api.util;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.MemorySegment;
+
+public class MemoryUtilsTest {
+
+
+	@Test
+	@DisplayName("On MemorySegment != NULL pointer, method returns utf8 string in the memory region")
+	void testValidSegmentReturnsString() {
+		try (var arena = Arena.ofConfined()) {
+			var address = arena.allocate(4);
+			address.setUtf8String(0, "abc");
+			String result = MemoryUtils.toUtf8StringOrNull(address);
+			Assertions.assertEquals("abc", result);
+		}
+	}
+
+	@Test
+	@DisplayName("With offset, on MemorySegment != NULL pointer, method returns utf8 string in the memory region")
+	void testValidSegmentReturnsStringAtOffset() {
+		try (var arena = Arena.ofConfined()) {
+			var address = arena.allocate(10);
+			address.setUtf8String(5, "abc");
+			String result = MemoryUtils.toUtf8StringOrNull(address, 5);
+			Assertions.assertEquals("abc", result);
+		}
+	}
+
+	@Test
+	@DisplayName("When MemorySegment == NULL pointer, method returns null")
+	void testNullPointerSegmentReturnsNull() {
+		String result = MemoryUtils.toUtf8StringOrNull(MemorySegment.NULL, 0);
+		Assertions.assertNull(result);
+	}
+}

jfuse-linux-aarch64/src/main/java/org/cryptomator/jfuse/linux/aarch64/FileInfoImpl.java

@@ -3,6 +3,7 @@
 import org.cryptomator.jfuse.api.FileInfo;
 import org.cryptomator.jfuse.linux.aarch64.extr.fcntl.fcntl_h;
 import org.cryptomator.jfuse.linux.aarch64.extr.fuse3.fuse_file_info;
+import org.jetbrains.annotations.Nullable;
 
 import java.lang.foreign.Arena;
 import java.lang.foreign.MemorySegment;
@@ -22,6 +23,18 @@ record FileInfoImpl(MemorySegment segment) implements FileInfo {
 	private static final int O_SYNC = fcntl_h.O_SYNC();
 	private static final int O_DSYNC = fcntl_h.O_DSYNC();
 
+	/**
+	 * Factory method to map native memory to an {@link FileInfo} object
+	 *
+	 * @param address the {@link MemorySegment} representing the starting address
+	 * @param scope   the {@link Arena} in which this object will be alive
+	 * @return an {@link FileInfo} object or {@code null} if {@code address} is a NULL pointer
+	 */
+	@Nullable
+	public static FileInfoImpl of(MemorySegment address, Arena scope) {
+		return MemorySegment.NULL.equals(address) ? null : new FileInfoImpl(address, scope);
+	}
+
 	public FileInfoImpl(MemorySegment address, Arena scope) {
 		this(fuse_file_info.ofAddress(address, scope));
 	}

jfuse-linux-aarch64/src/main/java/org/cryptomator/jfuse/linux/aarch64/FuseImpl.java

@@ -5,6 +5,7 @@
 import org.cryptomator.jfuse.api.FuseMount;
 import org.cryptomator.jfuse.api.FuseMountFailedException;
 import org.cryptomator.jfuse.api.FuseOperations;
+import org.cryptomator.jfuse.api.util.MemoryUtils;
 import org.cryptomator.jfuse.linux.aarch64.extr.fuse3.fuse_args;
 import org.cryptomator.jfuse.linux.aarch64.extr.fuse3.fuse_h;
 import org.cryptomator.jfuse.linux.aarch64.extr.fuse3.fuse_operations;
@@ -116,14 +117,14 @@ private int access(MemorySegment path, int mask) {
 
 	private int chmod(MemorySegment path, int mode, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chmod(path.getUtf8String(0), mode, new FileInfoImpl(fi, arena));
+			return fuseOperations.chmod(path.getUtf8String(0), mode, FileInfoImpl.of(fi, arena));
 		}
 	}
 
 	@VisibleForTesting
 	int chown(MemorySegment path, int uid, int gid, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chown(path.getUtf8String(0), uid, gid, new FileInfoImpl(fi, arena));
+			return fuseOperations.chown(path.getUtf8String(0), uid, gid, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -154,13 +155,13 @@ int fsync(MemorySegment path, int datasync, MemorySegment fi) {
 	@VisibleForTesting
 	int fsyncdir(MemorySegment path, int datasync, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.fsyncdir(path.getUtf8String(0), datasync, new FileInfoImpl(fi, arena));
+			return fuseOperations.fsyncdir(MemoryUtils.toUtf8StringOrNull(path), datasync, new FileInfoImpl(fi, arena));
 		}
 	}
 
 	private int getattr(MemorySegment path, MemorySegment stat, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), new FileInfoImpl(fi, arena));
+			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -229,7 +230,7 @@ private int release(MemorySegment path, MemorySegment fi) {
 
 	private int releasedir(MemorySegment path, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.releasedir(path.getUtf8String(0), new FileInfoImpl(fi, arena));
+			return fuseOperations.releasedir(MemoryUtils.toUtf8StringOrNull(path), new FileInfoImpl(fi, arena));
 		}
 	}
 
@@ -253,7 +254,7 @@ private int symlink(MemorySegment linkname, MemorySegment target) {
 
 	private int truncate(MemorySegment path, long size, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.truncate(path.getUtf8String(0), size, new FileInfoImpl(fi, arena));
+			return fuseOperations.truncate(path.getUtf8String(0), size, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -271,11 +272,11 @@ int utimens(MemorySegment path, MemorySegment times, MemorySegment fi) {
 				timespec.tv_sec$set(segment, 0);
 				timespec.tv_nsec$set(segment, stat_h.UTIME_NOW());
 				var time = new TimeSpecImpl(segment);
-				return fuseOperations.utimens(path.getUtf8String(0), time, time, new FileInfoImpl(fi, arena));
+				return fuseOperations.utimens(path.getUtf8String(0), time, time, FileInfoImpl.of(fi, arena));
 			} else {
 				var time0 = times.asSlice(0, timespec.$LAYOUT().byteSize());
 				var time1 = times.asSlice(timespec.$LAYOUT().byteSize(), timespec.$LAYOUT().byteSize());
-				return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), new FileInfoImpl(fi, arena));
+				return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), FileInfoImpl.of(fi, arena));
 			}
 		}
 	}

jfuse-linux-amd64/src/main/java/org/cryptomator/jfuse/linux/amd64/FileInfoImpl.java

@@ -3,6 +3,7 @@
 import org.cryptomator.jfuse.api.FileInfo;
 import org.cryptomator.jfuse.linux.amd64.extr.fcntl.fcntl_h;
 import org.cryptomator.jfuse.linux.amd64.extr.fuse3.fuse_file_info;
+import org.jetbrains.annotations.Nullable;
 
 import java.lang.foreign.Arena;
 import java.lang.foreign.MemorySegment;
@@ -22,6 +23,18 @@ record FileInfoImpl(MemorySegment segment) implements FileInfo {
 	private static final int O_SYNC = fcntl_h.O_SYNC();
 	private static final int O_DSYNC = fcntl_h.O_DSYNC();
 
+	/**
+	 * Factory method to map native memory to an {@link FileInfo} object
+	 *
+	 * @param address the {@link MemorySegment} representing the starting address
+	 * @param scope   the {@link Arena} in which this object will be alive
+	 * @return an {@link FileInfo} object or {@code null} if {@code address} is a NULL pointer
+	 */
+	@Nullable
+	public static FileInfoImpl of(MemorySegment address, Arena scope) {
+		return MemorySegment.NULL.equals(address) ? null : new FileInfoImpl(address, scope);
+	}
+
 	public FileInfoImpl(MemorySegment address, Arena scope) {
 		this(fuse_file_info.ofAddress(address, scope));
 	}

jfuse-linux-amd64/src/main/java/org/cryptomator/jfuse/linux/amd64/FuseImpl.java

@@ -5,6 +5,7 @@
 import org.cryptomator.jfuse.api.FuseMount;
 import org.cryptomator.jfuse.api.FuseMountFailedException;
 import org.cryptomator.jfuse.api.FuseOperations;
+import org.cryptomator.jfuse.api.util.MemoryUtils;
 import org.cryptomator.jfuse.linux.amd64.extr.fuse3.fuse_args;
 import org.cryptomator.jfuse.linux.amd64.extr.fuse3.fuse_h;
 import org.cryptomator.jfuse.linux.amd64.extr.fuse3.fuse_operations;
@@ -116,14 +117,14 @@ private int access(MemorySegment path, int mask) {
 
 	private int chmod(MemorySegment path, int mode, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chmod(path.getUtf8String(0), mode, new FileInfoImpl(fi, arena));
+			return fuseOperations.chmod(path.getUtf8String(0), mode, FileInfoImpl.of(fi, arena));
 		}
 	}
 
 	@VisibleForTesting
 	int chown(MemorySegment path, int uid, int gid, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chown(path.getUtf8String(0), uid, gid, new FileInfoImpl(fi, arena));
+			return fuseOperations.chown(path.getUtf8String(0), uid, gid, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -154,13 +155,13 @@ int fsync(MemorySegment path, int datasync, MemorySegment fi) {
 	@VisibleForTesting
 	int fsyncdir(MemorySegment path, int datasync, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.fsyncdir(path.getUtf8String(0), datasync, new FileInfoImpl(fi, arena));
+			return fuseOperations.fsyncdir(MemoryUtils.toUtf8StringOrNull(path), datasync, new FileInfoImpl(fi, arena));
 		}
 	}
 
 	private int getattr(MemorySegment path, MemorySegment stat, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), new FileInfoImpl(fi, arena));
+			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -229,7 +230,7 @@ private int release(MemorySegment path, MemorySegment fi) {
 
 	private int releasedir(MemorySegment path, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.releasedir(path.getUtf8String(0), new FileInfoImpl(fi, arena));
+			return fuseOperations.releasedir(MemoryUtils.toUtf8StringOrNull(path), new FileInfoImpl(fi, arena));
 		}
 	}
 
@@ -253,7 +254,7 @@ private int symlink(MemorySegment linkname, MemorySegment target) {
 
 	private int truncate(MemorySegment path, long size, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.truncate(path.getUtf8String(0), size, new FileInfoImpl(fi, arena));
+			return fuseOperations.truncate(path.getUtf8String(0), size, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -270,11 +271,11 @@ int utimens(MemorySegment path, MemorySegment times, MemorySegment fi) {
 				timespec.tv_sec$set(segment, 0);
 				timespec.tv_nsec$set(segment, stat_h.UTIME_NOW());
 				var time = new TimeSpecImpl(segment);
-				return fuseOperations.utimens(path.getUtf8String(0), time, time, new FileInfoImpl(fi, arena));
+				return fuseOperations.utimens(path.getUtf8String(0), time, time, FileInfoImpl.of(fi, arena));
 			} else {
 				var time0 = times.asSlice(0, timespec.$LAYOUT().byteSize());
 				var time1 = times.asSlice(timespec.$LAYOUT().byteSize(), timespec.$LAYOUT().byteSize());
-				return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), new FileInfoImpl(fi, arena));
+				return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), FileInfoImpl.of(fi, arena));
 			}
 		}
 	}

jfuse-mac/src/main/java/org/cryptomator/jfuse/mac/FuseImpl.java

@@ -4,6 +4,7 @@
 import org.cryptomator.jfuse.api.FuseMount;
 import org.cryptomator.jfuse.api.FuseMountFailedException;
 import org.cryptomator.jfuse.api.FuseOperations;
+import org.cryptomator.jfuse.api.util.MemoryUtils;
 import org.cryptomator.jfuse.mac.extr.fuse.fuse_args;
 import org.cryptomator.jfuse.mac.extr.fuse.fuse_h;
 import org.cryptomator.jfuse.mac.extr.fuse.fuse_operations;
@@ -154,7 +155,7 @@ int fsync(MemorySegment path, int datasync, MemorySegment fi) {
 	@VisibleForTesting
 	int fsyncdir(MemorySegment path, int datasync, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.fsyncdir(path.getUtf8String(0), datasync, new FileInfoImpl(fi, arena));
+			return fuseOperations.fsyncdir(MemoryUtils.toUtf8StringOrNull(path), datasync, new FileInfoImpl(fi, arena));
 		}
 	}
 
@@ -237,7 +238,7 @@ private int release(MemorySegment path, MemorySegment fi) {
 
 	private int releasedir(MemorySegment path, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.releasedir(path.getUtf8String(0), new FileInfoImpl(fi, arena));
+			return fuseOperations.releasedir(MemoryUtils.toUtf8StringOrNull(path), new FileInfoImpl(fi, arena));
 		}
 	}
 

jfuse-win/src/main/java/org/cryptomator/jfuse/win/FileInfoImpl.java

@@ -3,6 +3,7 @@
 import org.cryptomator.jfuse.api.FileInfo;
 import org.cryptomator.jfuse.win.extr.fcntl.fcntl_h;
 import org.cryptomator.jfuse.win.extr.fuse3.fuse3_file_info;
+import org.jetbrains.annotations.Nullable;
 
 import java.lang.foreign.Arena;
 import java.lang.foreign.MemorySegment;
@@ -20,6 +21,18 @@ record FileInfoImpl(MemorySegment segment) implements FileInfo {
 	private static final int O_TRUNC = fcntl_h.O_TRUNC();
 	private static final int O_EXCL = fcntl_h.O_EXCL();
 
+	/**
+	 * Factory method to map native memory to an {@link FileInfo} object
+	 *
+	 * @param address the {@link MemorySegment} representing the starting address
+	 * @param scope   the {@link Arena} in which this object will be alive
+	 * @return an {@link FileInfo} object or {@code null} if {@code address} is a NULL pointer
+	 */
+	@Nullable
+	public static FileInfoImpl of(MemorySegment address, Arena scope) {
+		return MemorySegment.NULL.equals(address) ? null : new FileInfoImpl(address, scope);
+	}
+
 	public FileInfoImpl(MemorySegment address, Arena scope) {
 		this(fuse3_file_info.ofAddress(address, scope));
 	}

jfuse-win/src/main/java/org/cryptomator/jfuse/win/FuseImpl.java

@@ -5,6 +5,7 @@
 import org.cryptomator.jfuse.api.FuseMount;
 import org.cryptomator.jfuse.api.FuseMountFailedException;
 import org.cryptomator.jfuse.api.FuseOperations;
+import org.cryptomator.jfuse.api.util.MemoryUtils;
 import org.cryptomator.jfuse.win.extr.fuse2.fuse2_h;
 import org.cryptomator.jfuse.win.extr.fuse2.fuse_args;
 import org.cryptomator.jfuse.win.extr.fuse3.fuse3_operations;
@@ -125,14 +126,14 @@ MemorySegment init(MemorySegment conn, MemorySegment cfg) {
 
 	private int chmod(MemorySegment path, int mode, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chmod(path.getUtf8String(0), mode, new FileInfoImpl(fi, arena));
+			return fuseOperations.chmod(path.getUtf8String(0), mode, FileInfoImpl.of(fi, arena));
 		}
 	}
 
 	@VisibleForTesting
 	int chown(MemorySegment path, int uid, int gid, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.chown(path.getUtf8String(0), uid, gid, new FileInfoImpl(fi, arena));
+			return fuseOperations.chown(path.getUtf8String(0), uid, gid, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -163,14 +164,14 @@ int fsync(MemorySegment path, int datasync, MemorySegment fi) {
 	@VisibleForTesting
 	int fsyncdir(MemorySegment path, int datasync, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.fsyncdir(path.getUtf8String(0), datasync, new FileInfoImpl(fi, arena));
+			return fuseOperations.fsyncdir(MemoryUtils.toUtf8StringOrNull(path), datasync, new FileInfoImpl(fi, arena));
 		}
 	}
 
 	@VisibleForTesting
 	int getattr(MemorySegment path, MemorySegment stat, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), new FileInfoImpl(fi, arena));
+			return fuseOperations.getattr(path.getUtf8String(0), new StatImpl(stat, arena), FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -239,7 +240,7 @@ private int release(MemorySegment path, MemorySegment fi) {
 
 	private int releasedir(MemorySegment path, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.releasedir(path.getUtf8String(0), new FileInfoImpl(fi, arena));
+			return fuseOperations.releasedir(MemoryUtils.toUtf8StringOrNull(path), new FileInfoImpl(fi, arena));
 		}
 	}
 
@@ -264,7 +265,7 @@ private int symlink(MemorySegment linkname, MemorySegment target) {
 	@VisibleForTesting
 	int truncate(MemorySegment path, long size, MemorySegment fi) {
 		try (var arena = Arena.ofConfined()) {
-			return fuseOperations.truncate(path.getUtf8String(0), size, new FileInfoImpl(fi, arena));
+			return fuseOperations.truncate(path.getUtf8String(0), size, FileInfoImpl.of(fi, arena));
 		}
 	}
 
@@ -281,7 +282,7 @@ int utimens(MemorySegment path, MemorySegment times, MemorySegment fi) {
 			var segment = times.reinterpret(seq.byteSize());
 			var time0 = segment.asSlice(0, fuse_timespec.$LAYOUT().byteSize());
 			var time1 = segment.asSlice(fuse_timespec.$LAYOUT().byteSize(), fuse_timespec.$LAYOUT().byteSize());
-			return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), new FileInfoImpl(fi, arena));
+			return fuseOperations.utimens(path.getUtf8String(0), new TimeSpecImpl(time0), new TimeSpecImpl(time1), FileInfoImpl.of(fi, arena));
 		}
 	}