[JENKINS-36088] Use NIO implementations of chmod and mode by default (#3135)

* Use NIO for FilePath#chmod and IOUtils#mode

* Add tests for NIO mode and chmod implementations

* Add test, remove new method, and update JavaDoc

* Provide system property to use native implementations of chmod and mode

* Revert unrelated whitespace modification

* Don't remove exception from throws and put imports in original location

* Fix broken JavaDoc links

* Ignore file type bits (above 0o7777) in Util#modeToPermission

* Use octal for constants and don't include file type bits

* Revert unnecessary changes to TarArchiverTest

* Add assertion that non-permission bits are ignored by chmod

* Use NIO copy with StandardCopyOption.COPY_ATTRIBUTES in copyToWithPermissions where possible

* Catch InvalidPathException and convert it to IOException

* Create utility method for File#toPath and use File#createDirectories after review

* Remove useless calls to toAbsolutePath and getAbsoluteFile

* Fix typos and use octal for constant after review

* Add test for behavior of copyToWithPermission with special bits

core/src/test/java/hudson/FilePathTest.java

@@ -25,6 +25,7 @@ package hudson;
 
 import hudson.FilePath.TarCompression;
 import hudson.model.TaskListener;
+import hudson.os.PosixAPI;
 import hudson.remoting.VirtualChannel;
 import hudson.util.NullStream;
 import hudson.util.StreamTaskListener;
@@ -245,7 +246,7 @@ public class FilePathTest {
                     throw x;
                 }
             } finally {
-                toF.chmod(700);
+                toF.chmod(0700);
             }
     }
 
@@ -471,6 +472,25 @@ public class FilePathTest {
             }
     }
 
+    @Test public void copyToWithPermissionSpecialPermissions() throws IOException, InterruptedException {
+        assumeFalse("Test uses POSIX-specific features", Functions.isWindows());
+        File tmp = temp.getRoot();
+        File original = new File(tmp,"original");
+        FilePath originalP = new FilePath(channels.french, original.getPath());
+        originalP.touch(0);
+        PosixAPI.jnr().chmod(original.getAbsolutePath(), 02777); // Read/write/execute for everyone and setuid.
+
+        File sameChannelCopy = new File(tmp,"sameChannelCopy");
+        FilePath sameChannelCopyP = new FilePath(channels.french, sameChannelCopy.getPath());
+        originalP.copyToWithPermission(sameChannelCopyP);
+        assertEquals("Special permissions should be copied on the same machine", 02777, PosixAPI.jnr().stat(sameChannelCopy.getAbsolutePath()).mode() & 07777);
+
+        File diffChannelCopy = new File(tmp,"diffChannelCopy");
+        FilePath diffChannelCopyP = new FilePath(channels.british, diffChannelCopy.getPath());
+        originalP.copyToWithPermission(diffChannelCopyP);
+        assertEquals("Special permissions should not be copied across machines", 00777, PosixAPI.jnr().stat(diffChannelCopy.getAbsolutePath()).mode() & 07777);
+    }
+
     @Test public void symlinkInTar() throws Exception {
         assumeFalse("can't test on Windows", Functions.isWindows());
 
@@ -739,7 +759,38 @@ public class FilePathTest {
         // and now fail when flush is bad!
         tmpDirPath.child("../" + archive.getName()).untar(outDir, TarCompression.NONE);
     }
+    
+    @Test
+    public void chmod() throws Exception {
+        assumeFalse(Functions.isWindows());
+        File f = temp.newFile("file");
+        FilePath fp = new FilePath(f);
+        int prevMode = fp.mode();
+        assertEquals(0400, chmodAndMode(fp, 0400));
+        assertEquals(0412, chmodAndMode(fp, 0412));
+        assertEquals(0777, chmodAndMode(fp, 0777));
+        assertEquals(prevMode, chmodAndMode(fp, prevMode));
+    }
 
+    @Test
+    public void chmodInvalidPermissions() throws Exception {
+        assumeFalse(Functions.isWindows());
+        File f = temp.newFolder("folder");
+        FilePath fp = new FilePath(f);
+        int invalidMode = 01770; // Full permissions for owner and group plus sticky bit.
+        try {
+            chmodAndMode(fp, invalidMode);
+            fail("Setting sticky bit should fail");
+        } catch (IOException e) {
+            assertEquals("Invalid mode: " + invalidMode, e.getMessage());
+        }
+    }
+
+    private int chmodAndMode(FilePath path, int mode) throws Exception {
+        path.chmod(mode);
+        return path.mode();
+    }
+    
     @Test public void deleteRecursiveOnUnix() throws Exception {
         assumeFalse("Uses Unix-specific features", Functions.isWindows());
         Path targetDir = temp.newFolder("target").toPath();