Read Linux file attributes through the FFM API

resources/bundles/org.eclipse.core.filesystem/generateLinuxH.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# Regenerates the glibc bindings in src-gen. Needs jextract on the PATH,
+# https://jdk.java.net/jextract/, and has to run on Linux.
+#
+# No --library: that would emit libraryLookup("libc.so"), which cannot be opened
+# on glibc, where the library is libc.so.6. Without it the generated lookup falls
+# back to the linker's default lookup, which already sees libc.
+set -eu
+cd "$(dirname "$0")"
+
+cat > /tmp/LibC.h <<'HEADER'
+#define _GNU_SOURCE
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <linux/stat.h>
+#include <sys/stat.h>
+#include <unistd.h>
+HEADER
+
+jextract --output src-gen \
+	--include-function statx \
+	--include-function opendir \
+	--include-function readdir \
+	--include-function closedir \
+	--include-function dirfd \
+	--include-function readlinkat \
+	--include-function chmod \
+	--include-struct statx \
+	--include-struct statx_timestamp \
+	--include-struct dirent \
+	--include-constant AT_FDCWD \
+	--include-constant AT_SYMLINK_NOFOLLOW \
+	--include-constant AT_STATX_SYNC_AS_STAT \
+	--include-constant STATX_TYPE \
+	--include-constant STATX_MODE \
+	--include-constant STATX_SIZE \
+	--include-constant STATX_MTIME \
+	--include-constant ENOENT \
+	--include-constant PATH_MAX \
+	--include-constant S_IFMT \
+	--include-constant S_IFDIR \
+	--include-constant S_IFLNK \
+	--include-constant S_IRUSR --include-constant S_IWUSR --include-constant S_IXUSR \
+	--include-constant S_IRGRP --include-constant S_IWGRP --include-constant S_IXGRP \
+	--include-constant S_IROTH --include-constant S_IWOTH --include-constant S_IXOTH \
+	--target-package org.linux \
+	--header-class-name LibC \
+	/tmp/LibC.h

resources/bundles/org.eclipse.core.filesystem/src-gen/org/linux/LibC$shared.java

@@ -0,0 +1,63 @@
+// Generated by jextract
+
+package org.linux;
+
+import java.lang.invoke.*;
+import java.lang.foreign.*;
+import java.nio.ByteOrder;
+import java.util.*;
+import java.util.function.*;
+import java.util.stream.*;
+
+import static java.lang.foreign.ValueLayout.*;
+import static java.lang.foreign.MemoryLayout.PathElement.*;
+
+public class LibC$shared {
+
+    LibC$shared() {
+        // Should not be called directly
+    }
+
+    public static final ValueLayout.OfBoolean C_BOOL = (ValueLayout.OfBoolean) Linker.nativeLinker().canonicalLayouts().get("bool");
+    public static final ValueLayout.OfByte C_CHAR =(ValueLayout.OfByte)Linker.nativeLinker().canonicalLayouts().get("char");
+    public static final ValueLayout.OfShort C_SHORT = (ValueLayout.OfShort) Linker.nativeLinker().canonicalLayouts().get("short");
+    public static final ValueLayout.OfInt C_INT = (ValueLayout.OfInt) Linker.nativeLinker().canonicalLayouts().get("int");
+    public static final ValueLayout.OfLong C_LONG_LONG = (ValueLayout.OfLong) Linker.nativeLinker().canonicalLayouts().get("long long");
+    public static final ValueLayout.OfFloat C_FLOAT = (ValueLayout.OfFloat) Linker.nativeLinker().canonicalLayouts().get("float");
+    public static final ValueLayout.OfDouble C_DOUBLE = (ValueLayout.OfDouble) Linker.nativeLinker().canonicalLayouts().get("double");
+    public static final AddressLayout C_POINTER = ((AddressLayout) Linker.nativeLinker().canonicalLayouts().get("void*"))
+            .withTargetLayout(MemoryLayout.sequenceLayout(java.lang.Long.MAX_VALUE, C_CHAR));
+    public static final ValueLayout.OfLong C_LONG = (ValueLayout.OfLong) Linker.nativeLinker().canonicalLayouts().get("long");
+
+    static final boolean TRACE_DOWNCALLS = Boolean.getBoolean("jextract.trace.downcalls");
+
+    static void traceDowncall(String name, Object... args) {
+         String traceArgs = Arrays.stream(args)
+                       .map(Object::toString)
+                       .collect(Collectors.joining(", "));
+         System.out.printf("%s(%s)\n", name, traceArgs);
+    }
+
+    static MethodHandle upcallHandle(Class<?> fi, String name, FunctionDescriptor fdesc) {
+        try {
+            return MethodHandles.lookup().findVirtual(fi, name, fdesc.toMethodType());
+        } catch (ReflectiveOperationException ex) {
+            throw new AssertionError(ex);
+        }
+    }
+
+    static MemoryLayout align(MemoryLayout layout, long align) {
+        return switch (layout) {
+            case PaddingLayout p -> p;
+            case ValueLayout v -> v.withByteAlignment(align);
+            case GroupLayout g -> {
+                MemoryLayout[] alignedMembers = g.memberLayouts().stream()
+                        .map(m -> align(m, align)).toArray(MemoryLayout[]::new);
+                yield g instanceof StructLayout ?
+                        MemoryLayout.structLayout(alignedMembers) : MemoryLayout.unionLayout(alignedMembers);
+            }
+            case SequenceLayout s -> MemoryLayout.sequenceLayout(s.elementCount(), align(s.elementLayout(), align));
+        };
+    }
+}
+