8277489: Rewrite JAAS UnixLoginModule with FFM

make/modules/jdk.security.auth/Lib.gmk

@@ -31,13 +31,14 @@ include LibCommon.gmk
 ## Build libjaas
 ################################################################################
 
-$(eval $(call SetupJdkLibrary, BUILD_LIBJAAS, \
-    NAME := jaas, \
-    OPTIMIZATION := LOW, \
-    EXTRA_HEADER_DIRS := java.base:libjava, \
-    LIBS_windows := advapi32.lib mpr.lib netapi32.lib user32.lib, \
-))
-
-TARGETS += $(BUILD_LIBJAAS)
+ifeq ($(call isTargetOs, windows), true)
+  $(eval $(call SetupJdkLibrary, BUILD_LIBJAAS, \
+      NAME := jaas, \
+      OPTIMIZATION := LOW, \
+      EXTRA_HEADER_DIRS := java.base:libjava, \
+      LIBS_windows := advapi32.lib mpr.lib netapi32.lib user32.lib, \
+  ))
 
+  TARGETS += $(BUILD_LIBJAAS)
+endif
 ################################################################################

src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixLoginModule.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,6 @@
 package com.sun.security.auth.module;
 
 import java.util.*;
-import java.io.IOException;
 import javax.security.auth.*;
 import javax.security.auth.callback.*;
 import javax.security.auth.login.*;
@@ -127,10 +126,14 @@ public boolean login() throws LoginException {
             ss = new UnixSystem();
         } catch (UnsatisfiedLinkError ule) {
             succeeded = false;
-            throw new FailedLoginException
+            var error = new FailedLoginException
                                 ("Failed in attempt to import " +
                                 "the underlying system identity information" +
                                 " on " + System.getProperty("os.name"));
+            if (ule.getCause() != null) {
+                error.initCause(ule.getCause());
+            }
+            throw error;
         }
         userPrincipal = new UnixPrincipal(ss.getUsername());
         UIDPrincipal = new UnixNumericUserPrincipal(ss.getUid());
@@ -150,9 +153,10 @@ public boolean login() throws LoginException {
                     "succeeded importing info: ");
             System.out.println("\t\t\tuid = " + ss.getUid());
             System.out.println("\t\t\tgid = " + ss.getGid());
-            unixGroups = ss.getGroups();
-            for (int i = 0; i < unixGroups.length; i++) {
-                System.out.println("\t\t\tsupp gid = " + unixGroups[i]);
+            if (unixGroups != null) {
+                for (int i = 0; i < unixGroups.length; i++) {
+                    System.out.println("\t\t\tsupp gid = " + unixGroups[i]);
+                }
             }
         }
         succeeded = true;

src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixSystem.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,14 @@
 
 package com.sun.security.auth.module;
 
+import jdk.internal.ffi.generated.jaas_unix.passwd;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.ValueLayout;
+
+import static jdk.internal.ffi.generated.jaas_unix.jaas_unix_h.*;
+
 /**
  * This class implementation retrieves and makes available Unix
  * UID/GID/groups information for the current user.
@@ -33,10 +41,6 @@
  */
 public class UnixSystem {
 
-    private native void getUnixInfo();
-
-    // Warning: the following 4 fields are used by Unix.c
-
     /** The current username. */
     protected String username;
 
@@ -53,10 +57,42 @@ public class UnixSystem {
      * Instantiate a {@code UnixSystem} and load
      * the native library to access the underlying system information.
      */
-    @SuppressWarnings("restricted")
     public UnixSystem() {
-        System.loadLibrary("jaas");
-        getUnixInfo();
+        try (Arena scope = Arena.ofConfined()) {
+            int groupnum = getgroups(0, MemorySegment.NULL);
+            if (groupnum == -1) {
+                throw new RuntimeException("getgroups returns " + groupnum);
+            }
+
+            var gs = scope.allocate(gid_t, groupnum);
+            groupnum = getgroups(groupnum, gs);
+            if (groupnum == -1) {
+                throw new RuntimeException("getgroups returns " + groupnum);
+            }
+
+            groups = new long[groupnum];
+            for (int i = 0; i < groupnum; i++) {
+                groups[i] = gs.getAtIndex(gid_t, i);
+            }
+
+            var resbuf = passwd.allocate(scope);
+            var pwd = scope.allocate(C_POINTER);
+            var pwd_buf = scope.allocate(1024);
+            int out = getpwuid_r(getuid(), resbuf, pwd_buf, pwd_buf.byteSize(), pwd);
+            if (out != 0) {
+                throw new RuntimeException("getpwuid_r returns " + out);
+            }
+            if (pwd.get(ValueLayout.ADDRESS, 0).equals(MemorySegment.NULL)) {
+                throw new RuntimeException("getpwuid_r returns NULL result");
+            }
+            uid = passwd.pw_uid(resbuf);
+            gid = passwd.pw_gid(resbuf);
+            username = passwd.pw_name(resbuf).getString(0);
+        } catch (Throwable t) {
+            var error = new UnsatisfiedLinkError("FFM calls failed");
+            error.initCause(t);
+            throw error;
+        }
     }
 
     /**

src/jdk.security.auth/share/classes/jdk/internal/ffi/generated/jaas_unix/jaas_unix_h$shared.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+// Generated by jextract
+
+package jdk.internal.ffi.generated.jaas_unix;
+
+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.*;
+
+@SuppressWarnings("restricted")
+public class jaas_unix_h$shared {
+
+    jaas_unix_h$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));
+        };
+    }
+}