From 9a724be5b3c762f4845a802adc5f535c83473469 Mon Sep 17 00:00:00 2001
From: Guillaume Nodet <gnodet@gmail.com>
Date: Mon, 10 May 2021 11:24:37 +0200
Subject: [PATCH] [SSHD-525] Server side implementation of
 posix-rename@openssh.com

---
 CHANGES.md                                    |  2 +-
 .../server/AbstractSftpSubsystemHelper.java   | 24 ++++++++++-
 .../helpers/OpenSSHExtensionsTest.java        | 41 +++++++++++++++++++
 3 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 751f15bd5..b2d5345a4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -21,7 +21,7 @@
 
 ## Minor code helpers
 
-* [SSHD-525](https://issues.apache.org/jira/browse/SSHD-525) Added support for SFTP **client-side** ["posix-rename@openssh.com"
+* [SSHD-525](https://issues.apache.org/jira/browse/SSHD-525) Added support for SFTP `posix-rename@openssh.com`
  extension](http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=1.28&content-type=text/x-cvsweb-markup) - see section 3.3
 * [SSHD-1083](https://issues.apache.org/jira/browse/SSHD-1083) Relaxed required `Nio2Connector/Acceptor` required constructor arguments
 * [SSHD-1085](https://issues.apache.org/jira/browse/SSHD-1085) Added `CliLogger` + more verbosity on `SshClientMain`
diff --git a/sshd-sftp/src/main/java/org/apache/sshd/sftp/server/AbstractSftpSubsystemHelper.java b/sshd-sftp/src/main/java/org/apache/sshd/sftp/server/AbstractSftpSubsystemHelper.java
index 05f6e7417..d2d2c5a68 100644
--- a/sshd-sftp/src/main/java/org/apache/sshd/sftp/server/AbstractSftpSubsystemHelper.java
+++ b/sshd-sftp/src/main/java/org/apache/sshd/sftp/server/AbstractSftpSubsystemHelper.java
@@ -99,6 +99,7 @@
 import org.apache.sshd.sftp.common.extensions.openssh.FsyncExtensionParser;
 import org.apache.sshd.sftp.common.extensions.openssh.HardLinkExtensionParser;
 import org.apache.sshd.sftp.common.extensions.openssh.LSetStatExtensionParser;
+import org.apache.sshd.sftp.common.extensions.openssh.PosixRenameExtensionParser;
 
 /**
  * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
@@ -130,7 +131,8 @@ NavigableMapBuilder.<String, OptionalFeature> builder()
             Arrays.asList(
                     new OpenSSHExtension(FsyncExtensionParser.NAME, "1"),
                     new OpenSSHExtension(HardLinkExtensionParser.NAME, "1"),
-                    new OpenSSHExtension(LSetStatExtensionParser.NAME, "1")));
+                    new OpenSSHExtension(LSetStatExtensionParser.NAME, "1"),
+                    new OpenSSHExtension(PosixRenameExtensionParser.NAME, "1")));
 
     public static final List<String> DEFAULT_OPEN_SSH_EXTENSIONS_NAMES = Collections.unmodifiableList(
             NamedResource.getNameList(DEFAULT_OPEN_SSH_EXTENSIONS));
@@ -1226,6 +1228,23 @@ protected void doRename(int id, String oldPath, String newPath, Collection<CopyO
         listener.moved(session, o, n, opts, null);
     }
 
+    // see https://github.com/openssh/openssh-portable/blob/master/PROTOCOL section 3.3
+    protected void doPosixRename(Buffer buffer, int id) throws IOException {
+        String oldPath = buffer.getString();
+        String newPath = buffer.getString();
+        try {
+            int flags = SftpConstants.SSH_FXP_RENAME_ATOMIC | SftpConstants.SSH_FXP_RENAME_OVERWRITE;
+            doRename(id, oldPath, newPath, flags);
+        } catch (IOException | RuntimeException e) {
+            sendStatus(prepareReply(buffer), id, e,
+                    SftpConstants.SSH_FXP_EXTENDED, SftpConstants.SSH_FXP_RENAME,
+                    oldPath, newPath);
+            return;
+        }
+
+        sendStatus(prepareReply(buffer), id, SftpConstants.SSH_FX_OK, "");
+    }
+
     // see https://tools.ietf.org/html/draft-ietf-secsh-filexfer-extensions-00#section-7
     protected void doCopyData(Buffer buffer, int id) throws IOException {
         String readHandle = buffer.getString();
@@ -1740,6 +1759,9 @@ protected void executeExtendedCommand(Buffer buffer, int id, String extension) t
             case LSetStatExtensionParser.NAME:
                 doSetStat(buffer, id, extension, -1, Boolean.FALSE);
                 break;
+            case PosixRenameExtensionParser.NAME:
+                doPosixRename(buffer, id);
+                break;
             default:
                 doUnsupportedExtension(buffer, id, extension);
         }
diff --git a/sshd-sftp/src/test/java/org/apache/sshd/sftp/client/extensions/openssh/helpers/OpenSSHExtensionsTest.java b/sshd-sftp/src/test/java/org/apache/sshd/sftp/client/extensions/openssh/helpers/OpenSSHExtensionsTest.java
index 4a81808e4..bdcd9c9dc 100644
--- a/sshd-sftp/src/test/java/org/apache/sshd/sftp/client/extensions/openssh/helpers/OpenSSHExtensionsTest.java
+++ b/sshd-sftp/src/test/java/org/apache/sshd/sftp/client/extensions/openssh/helpers/OpenSSHExtensionsTest.java
@@ -20,6 +20,7 @@
 package org.apache.sshd.sftp.client.extensions.openssh.helpers;
 
 import java.io.IOException;
+import java.io.OutputStream;
 import java.io.StreamCorruptedException;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
@@ -41,10 +42,12 @@
 import org.apache.sshd.sftp.client.SftpClient;
 import org.apache.sshd.sftp.client.SftpClient.CloseableHandle;
 import org.apache.sshd.sftp.client.extensions.openssh.OpenSSHFsyncExtension;
+import org.apache.sshd.sftp.client.extensions.openssh.OpenSSHPosixRenameExtension;
 import org.apache.sshd.sftp.client.extensions.openssh.OpenSSHStatExtensionInfo;
 import org.apache.sshd.sftp.client.extensions.openssh.OpenSSHStatHandleExtension;
 import org.apache.sshd.sftp.client.extensions.openssh.OpenSSHStatPathExtension;
 import org.apache.sshd.sftp.common.SftpConstants;
+import org.apache.sshd.sftp.common.SftpException;
 import org.apache.sshd.sftp.common.extensions.openssh.AbstractOpenSSHExtensionParser.OpenSSHExtension;
 import org.apache.sshd.sftp.common.extensions.openssh.FstatVfsExtensionParser;
 import org.apache.sshd.sftp.common.extensions.openssh.StatVfsExtensionParser;
@@ -70,6 +73,44 @@ public void setUp() throws Exception {
         setupServer();
     }
 
+    @Test
+    public void testPosixRename() throws IOException {
+        Path targetPath = detectTargetFolder();
+        Path lclSftp = CommonTestSupportUtils.resolve(
+                targetPath, SftpConstants.SFTP_SUBSYSTEM_NAME, getClass().getSimpleName(), getCurrentTestName());
+        CommonTestSupportUtils.deleteRecursive(lclSftp);
+
+        Path parentPath = targetPath.getParent();
+        Path clientFolder = assertHierarchyTargetFolderExists(lclSftp.resolve("client"));
+        try (SftpClient sftp = createSingleSessionClient()) {
+            OpenSSHPosixRenameExtension rename = assertExtensionCreated(sftp, OpenSSHPosixRenameExtension.class);
+
+            Path file1 = clientFolder.resolve("file-1.txt");
+            String file1Path = CommonTestSupportUtils.resolveRelativeRemotePath(parentPath, file1);
+            try (OutputStream os = sftp.write(file1Path, SftpClient.MIN_WRITE_BUFFER_SIZE)) {
+                os.write((getCurrentTestName() + "\n").getBytes(StandardCharsets.UTF_8));
+            }
+
+            Path file2 = clientFolder.resolve("file-2.txt");
+            String file2Path = CommonTestSupportUtils.resolveRelativeRemotePath(parentPath, file2);
+            Path file3 = clientFolder.resolve("file-3.txt");
+            String file3Path = CommonTestSupportUtils.resolveRelativeRemotePath(parentPath, file3);
+            try {
+                rename.posixRename(file2Path, file3Path);
+                fail("Unxpected rename success of " + file2Path + " => " + file3Path);
+            } catch (SftpException e) {
+                assertEquals("Mismatched status for failed rename of " + file2Path + " => " + file3Path,
+                        SftpConstants.SSH_FX_NO_SUCH_FILE, e.getStatus());
+            }
+
+            try (OutputStream os = sftp.write(file2Path, SftpClient.MIN_WRITE_BUFFER_SIZE)) {
+                os.write("h".getBytes(StandardCharsets.UTF_8));
+            }
+
+            rename.posixRename(file1Path, file2Path);
+        }
+    }
+
     @Test
     public void testFsync() throws IOException {
         Path targetPath = detectTargetFolder();