Add safety check for local --remove-source-files.

A local_server copy now includes the dev+ino info from the destination
file so that the sender can make sure that it is not going to delete
the destination file.  Fixes mistakes such as:

  rsync -aiv --remove-source-files dir .

NEWS.md

@@ -10,6 +10,11 @@
 - Fixed a bug with the new file-list validation code when the last line of the
   [`--files-from`](rsync.1#opt) list is not terminated by a newline.
 
+- Added a safety check that prevents the sender from removing destination files
+  when a local copy using [`--remove-source-files`](rsync.1#opt) has some
+  content that is shared between the sending & receiving hierarchies, including
+  the case where the source dir & destination dir are identical.
+
 - Fixed a bug in the internal MD4 checksum code that could cause the digest
   to be sporadically incorrect (the openssl version was/is fine).
 

generator.c

@@ -1819,7 +1819,7 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 			goto cleanup;
 	  return_with_success:
 		if (!dry_run)
-			send_msg_int(MSG_SUCCESS, ndx);
+			send_msg_success(fname, ndx);
 		goto cleanup;
 	}
 

hlink.c

@@ -446,7 +446,7 @@ int hard_link_check(struct file_struct *file, int ndx, char *fname,
 		return -1;
 
 	if (remove_source_files == 1 && do_xfers)
-		send_msg_int(MSG_SUCCESS, ndx);
+		send_msg_success(fname, ndx);
 
 	return 1;
 }
@@ -519,7 +519,7 @@ void finish_hard_link(struct file_struct *file, const char *fname, int fin_ndx,
 		if (val < 0)
 			continue;
 		if (remove_source_files == 1 && do_xfers)
-			send_msg_int(MSG_SUCCESS, ndx);
+			send_msg_success(fname, ndx);
 	}
 
 	if (inc_recurse) {

io.c

@@ -41,6 +41,7 @@ extern int am_server;
 extern int am_sender;
 extern int am_receiver;
 extern int am_generator;
+extern int local_server;
 extern int msgs2stderr;
 extern int inc_recurse;
 extern int io_error;
@@ -84,6 +85,8 @@ int sock_f_out = -1;
 int64 total_data_read = 0;
 int64 total_data_written = 0;
 
+char num_dev_ino_buf[4 + 8 + 8];
+
 static struct {
 	xbuf in, out, msg;
 	int in_fd;
@@ -1064,6 +1067,24 @@ void send_msg_int(enum msgcode code, int num)
 	send_msg(code, numbuf, 4, -1);
 }
 
+void send_msg_success(const char *fname, int num)
+{
+	if (local_server) {
+		STRUCT_STAT st;
+
+		if (DEBUG_GTE(IO, 1))
+			rprintf(FINFO, "[%s] send_msg_success(%d)\n", who_am_i(), num);
+
+		if (stat(fname, &st) < 0)
+			memset(&st, 0, sizeof (STRUCT_STAT));
+		SIVAL(num_dev_ino_buf, 0, num);
+		SIVAL64(num_dev_ino_buf, 4, st.st_dev);
+		SIVAL64(num_dev_ino_buf, 4+8, st.st_ino);
+		send_msg(MSG_SUCCESS, num_dev_ino_buf, sizeof num_dev_ino_buf, -1);
+	} else
+		send_msg_int(MSG_SUCCESS, num);
+}
+
 static void got_flist_entry_status(enum festatus status, int ndx)
 {
 	struct file_list *flist = flist_for_ndx(ndx, "got_flist_entry_status");
@@ -1078,8 +1099,12 @@ static void got_flist_entry_status(enum festatus status, int ndx)
 
 	switch (status) {
 	case FES_SUCCESS:
-		if (remove_source_files)
-			send_msg_int(MSG_SUCCESS, ndx);
+		if (remove_source_files) {
+			if (local_server)
+				send_msg(MSG_SUCCESS, num_dev_ino_buf, sizeof num_dev_ino_buf, -1);
+			else
+				send_msg_int(MSG_SUCCESS, ndx);
+		}
 		/* FALL THROUGH */
 	case FES_NO_SEND:
 #ifdef SUPPORT_HARD_LINKS
@@ -1574,14 +1599,15 @@ static void read_a_msg(void)
 		}
 		break;
 	case MSG_SUCCESS:
-		if (msg_bytes != 4) {
+		if (msg_bytes != (local_server ? 4+8+8 : 4)) {
 		  invalid_msg:
 			rprintf(FERROR, "invalid multi-message %d:%lu [%s%s]\n",
 				tag, (unsigned long)msg_bytes, who_am_i(),
 				inc_recurse ? "/inc" : "");
 			exit_cleanup(RERR_STREAMIO);
 		}
-		val = raw_read_int();
+		raw_read_buf(num_dev_ino_buf, msg_bytes);
+		val = IVAL(num_dev_ino_buf, 0);
 		iobuf.in_multiplexed = 1;
 		if (am_generator)
 			got_flist_entry_status(FES_SUCCESS, val);

receiver.c

@@ -439,9 +439,8 @@ static void handle_delayed_updates(char *local_name)
 					"rename failed for %s (from %s)",
 					full_fname(fname), partialptr);
 			} else {
-				if (remove_source_files
-				 || (preserve_hard_links && F_IS_HLINKED(file)))
-					send_msg_int(MSG_SUCCESS, ndx);
+				if (remove_source_files || (preserve_hard_links && F_IS_HLINKED(file)))
+					send_msg_success(fname, ndx);
 				handle_partial_dir(partialptr, PDIR_DELETE);
 			}
 		}
@@ -698,7 +697,7 @@ int recv_files(int f_in, int f_out, char *local_name)
 			if (!am_server)
 				discard_receive_data(f_in, file);
 			if (inc_recurse)
-				send_msg_int(MSG_SUCCESS, ndx);
+				send_msg_success(fname, ndx);
 			continue;
 		}
 
@@ -926,9 +925,8 @@ int recv_files(int f_in, int f_out, char *local_name)
 		case 2:
 			break;
 		case 1:
-			if (remove_source_files || inc_recurse
-			 || (preserve_hard_links && F_IS_HLINKED(file)))
-				send_msg_int(MSG_SUCCESS, ndx);
+			if (remove_source_files || inc_recurse || (preserve_hard_links && F_IS_HLINKED(file)))
+				send_msg_success(fname, ndx);
 			break;
 		case 0: {
 			enum logcode msgtype = redoing ? FERROR_XFER : FWARNING;

rsync.1.md

@@ -1808,6 +1808,10 @@ expand it.
     Starting with 3.1.0, rsync will skip the sender-side removal (and output an
     error) if the file's size or modify time has not stayed unchanged.
 
+    Starting with 3.2.6, a local rsync copy will ensure that the sender does
+    not remove a file the receiver just verified, such as when the user
+    accidentally makes the source and destination directory the same path.
+
 0.  `--delete`
 
     This tells rsync to delete extraneous files from the receiving side (ones

sender.c

@@ -25,6 +25,7 @@
 extern int do_xfers;
 extern int am_server;
 extern int am_daemon;
+extern int local_server;
 extern int inc_recurse;
 extern int log_before_transfer;
 extern int stdout_format_has_i;
@@ -51,6 +52,7 @@ extern int file_old_total;
 extern BOOL want_progress_now;
 extern struct stats stats;
 extern struct file_list *cur_flist, *first_flist, *dir_flist;
+extern char num_dev_ino_buf[4 + 8 + 8];
 
 BOOL extra_flist_sending_enabled;
 
@@ -144,6 +146,13 @@ void successful_send(int ndx)
 		goto failed;
 	}
 
+	if (local_server
+	 && (int64)st.st_dev == IVAL64(num_dev_ino_buf, 4)
+	 && (int64)st.st_ino == IVAL64(num_dev_ino_buf, 4 + 8)) {
+		rprintf(FERROR_XFER, "ERROR: Skipping sender remove of destination file: %s\n", fname);
+		return;
+	}
+
 	if (st.st_size != F_LENGTH(file) || st.st_mtime != file->modtime
 #ifdef ST_MTIME_NSEC
 	 || (NSEC_BUMP(file) && (uint32)st.ST_MTIME_NSEC != F_MOD_NSEC(file))