X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/574c250093f19e1876c4af0de704ac219783b805..ac669e8b922c7ace230294f9bf9a3a2bdfbd19d2:/io.c

diff --git a/io.c b/io.c
index 2a7d7762..dd99913d 100644
--- a/io.c
+++ b/io.c
@@ -43,19 +43,23 @@ extern int bwlimit;
 extern size_t bwlimit_writemax;
 extern int verbose;
 extern int io_timeout;
+extern int allowed_lull;
 extern int am_server;
 extern int am_daemon;
 extern int am_sender;
 extern int am_generator;
 extern int eol_nulls;
+extern int read_batch;
 extern int csum_length;
 extern int checksum_seed;
 extern int protocol_version;
-extern char *remote_filesfrom_file;
+extern int remove_sent_files;
+extern int preserve_hard_links;
+extern char *filesfrom_host;
 extern struct stats stats;
+extern struct file_list *the_file_list;
 
 const char phase_unknown[] = "unknown";
-int select_timeout = SELECT_TIMEOUT;
 int ignore_timeout = 0;
 int batch_fd = -1;
 int batch_gen_fd = -1;
@@ -76,20 +80,18 @@ int batch_gen_fd = -1;
 const char *io_write_phase = phase_unknown;
 const char *io_read_phase = phase_unknown;
 
-/* Ignore an EOF error if non-zero.  We exit if the value is 1 (used while
- * reading a module listing if the remote version is 24 or less) or go into a
- * sleep loop if the value is 2 (used by the receiver when it is reading a
- * potential end-of-transfer keep-alive message that may never come). */
+/* Ignore an EOF error if non-zero. See whine_about_eof(). */
 int kluge_around_eof = 0;
 
 int msg_fd_in = -1;
 int msg_fd_out = -1;
+int sock_f_in = -1;
+int sock_f_out = -1;
 
 static int io_multiplexing_out;
 static int io_multiplexing_in;
-static int sock_f_in = -1;
-static int sock_f_out = -1;
-static time_t last_io;
+static time_t last_io_in;
+static time_t last_io_out;
 static int no_flush;
 
 static int write_batch_monitor_in = -1;
@@ -101,39 +103,65 @@ static char io_filesfrom_buf[2048];
 static char *io_filesfrom_bp;
 static char io_filesfrom_lastchar;
 static int io_filesfrom_buflen;
+static size_t contiguous_write_len = 0;
+static int select_timeout = SELECT_TIMEOUT;
 
 static void read_loop(int fd, char *buf, size_t len);
 
-struct redo_list {
-	struct redo_list *next;
-	int num;
+struct flist_ndx_item {
+	struct flist_ndx_item *next;
+	int ndx;
 };
 
-static struct redo_list *redo_list_head;
-static struct redo_list *redo_list_tail;
+struct flist_ndx_list {
+	struct flist_ndx_item *head, *tail;
+};
 
-struct msg_list {
-	struct msg_list *next;
+static struct flist_ndx_list redo_list, hlink_list;
+
+struct msg_list_item {
+	struct msg_list_item *next;
 	char *buf;
 	int len;
 };
 
-static struct msg_list *msg_list_head;
-static struct msg_list *msg_list_tail;
+struct msg_list {
+	struct msg_list_item *head, *tail;
+};
+
+static struct msg_list msg_list;
 
-static void redo_list_add(int num)
+static void flist_ndx_push(struct flist_ndx_list *lp, int ndx)
 {
-	struct redo_list *rl;
-
-	if (!(rl = new(struct redo_list)))
-		exit_cleanup(RERR_MALLOC);
-	rl->next = NULL;
-	rl->num = num;
-	if (redo_list_tail)
-		redo_list_tail->next = rl;
+	struct flist_ndx_item *item;
+
+	if (!(item = new(struct flist_ndx_item)))
+		out_of_memory("flist_ndx_push");
+	item->next = NULL;
+	item->ndx = ndx;
+	if (lp->tail)
+		lp->tail->next = item;
 	else
-		redo_list_head = rl;
-	redo_list_tail = rl;
+		lp->head = item;
+	lp->tail = item;
+}
+
+static int flist_ndx_pop(struct flist_ndx_list *lp)
+{
+	struct flist_ndx_item *next;
+	int ndx;
+
+	if (!lp->head)
+		return -1;
+
+	ndx = lp->head->ndx;
+	next = lp->head->next;
+	free(lp->head);
+	lp->head = next;
+	if (!next)
+		lp->tail = NULL;
+
+	return ndx;
 }
 
 static void check_timeout(void)
@@ -143,17 +171,17 @@ static void check_timeout(void)
 	if (!io_timeout || ignore_timeout)
 		return;
 
-	if (!last_io) {
-		last_io = time(NULL);
+	if (!last_io_in) {
+		last_io_in = time(NULL);
 		return;
 	}
 
 	t = time(NULL);
 
-	if (t - last_io >= io_timeout) {
+	if (t - last_io_in >= io_timeout) {
 		if (!am_server && !am_daemon) {
 			rprintf(FERROR, "io timeout after %d seconds -- exiting\n",
-				(int)(t-last_io));
+				(int)(t-last_io_in));
 		}
 		exit_cleanup(RERR_TIMEOUT);
 	}
@@ -167,6 +195,18 @@ void io_set_sock_fds(int f_in, int f_out)
 	sock_f_out = f_out;
 }
 
+void set_io_timeout(int secs)
+{
+	io_timeout = secs;
+
+	if (!io_timeout || io_timeout > SELECT_TIMEOUT)
+		select_timeout = SELECT_TIMEOUT;
+	else
+		select_timeout = io_timeout;
+
+	allowed_lull = read_batch ? 0 : (io_timeout + 1) / 2;
+}
+
 /* Setup the fd used to receive MSG_* messages.  Only needed during the
  * early stages of being a local sender (up through the sending of the
  * file list) or when we're the generator (to fetch the messages from
@@ -187,31 +227,21 @@ void set_msg_fd_out(int fd)
 /* Add a message to the pending MSG_* list. */
 static void msg_list_add(int code, char *buf, int len)
 {
-	struct msg_list *ml;
+	struct msg_list_item *ml;
 
-	if (!(ml = new(struct msg_list)))
-		exit_cleanup(RERR_MALLOC);
+	if (!(ml = new(struct msg_list_item)))
+		out_of_memory("msg_list_add");
 	ml->next = NULL;
 	if (!(ml->buf = new_array(char, len+4)))
-		exit_cleanup(RERR_MALLOC);
+		out_of_memory("msg_list_add");
 	SIVAL(ml->buf, 0, ((code+MPLEX_BASE)<<24) | len);
 	memcpy(ml->buf+4, buf, len);
 	ml->len = len+4;
-	if (msg_list_tail)
-		msg_list_tail->next = ml;
+	if (msg_list.tail)
+		msg_list.tail->next = ml;
 	else
-		msg_list_head = ml;
-	msg_list_tail = ml;
-}
-
-void send_msg(enum msgcode code, char *buf, int len)
-{
-	if (msg_fd_out < 0) {
-		io_multiplex_write(code, buf, len);
-		return;
-	}
-	msg_list_add(code, buf, len);
-	msg_list_push(NORMAL_FLUSH);
+		msg_list.head = ml;
+	msg_list.tail = ml;
 }
 
 /* Read a message from the MSG_* fd and handle it.  This is called either
@@ -226,7 +256,7 @@ static void read_msg_fd(void)
 	int tag, len;
 
 	/* Temporarily disable msg_fd_in.  This is needed to avoid looping back
-	 * to this routine from read_timeout() and writefd_unbuffered(). */
+	 * to this routine from writefd_unbuffered(). */
 	msg_fd_in = -1;
 
 	read_loop(fd, buf, 4);
@@ -241,7 +271,7 @@ static void read_msg_fd(void)
 			rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 			exit_cleanup(RERR_STREAMIO);
 		}
-		redo_list_add(-1);
+		flist_ndx_push(&redo_list, -1);
 		break;
 	case MSG_REDO:
 		if (len != 4 || !am_generator) {
@@ -249,7 +279,7 @@ static void read_msg_fd(void)
 			exit_cleanup(RERR_STREAMIO);
 		}
 		read_loop(fd, buf, 4);
-		redo_list_add(IVAL(buf,0));
+		flist_ndx_push(&redo_list, IVAL(buf,0));
 		break;
 	case MSG_DELETED:
 		if (len >= (int)sizeof buf || !am_generator) {
@@ -265,8 +295,18 @@ static void read_msg_fd(void)
 			exit_cleanup(RERR_STREAMIO);
 		}
 		read_loop(fd, buf, len);
-		io_multiplex_write(MSG_SUCCESS, buf, len);
+		if (remove_sent_files)
+			io_multiplex_write(MSG_SUCCESS, buf, len);
+		if (preserve_hard_links)
+			flist_ndx_push(&hlink_list, IVAL(buf,0));
 		break;
+	case MSG_SOCKERR:
+		if (!am_generator) {
+			rprintf(FERROR, "invalid message %d:%d\n", tag, len);
+			exit_cleanup(RERR_STREAMIO);
+		}
+		close_multiplexing_out();
+		/* FALL THROUGH */
 	case MSG_INFO:
 	case MSG_ERROR:
 	case MSG_LOG:
@@ -290,7 +330,7 @@ static void read_msg_fd(void)
 /* Try to push messages off the list onto the wire.  If we leave with more
  * to do, return 0.  On error, return -1.  If everything flushed, return 1.
  * This is only active in the receiver. */
-int msg_list_push(int flush_it_all)
+static int msg_list_flush(int flush_it_all)
 {
 	static int written = 0;
 	struct timeval tv;
@@ -299,8 +339,8 @@ int msg_list_push(int flush_it_all)
 	if (msg_fd_out < 0)
 		return -1;
 
-	while (msg_list_head) {
-		struct msg_list *ml = msg_list_head;
+	while (msg_list.head) {
+		struct msg_list_item *ml = msg_list.head;
 		int n = write(msg_fd_out, ml->buf + written, ml->len - written);
 		if (n < 0) {
 			if (errno == EINTR)
@@ -317,9 +357,9 @@ int msg_list_push(int flush_it_all)
 				check_timeout();
 		} else if ((written += n) == ml->len) {
 			free(ml->buf);
-			msg_list_head = ml->next;
-			if (!msg_list_head)
-				msg_list_tail = NULL;
+			msg_list.head = ml->next;
+			if (!msg_list.head)
+				msg_list.tail = NULL;
 			free(ml);
 			written = 0;
 		}
@@ -327,22 +367,32 @@ int msg_list_push(int flush_it_all)
 	return 1;
 }
 
-int get_redo_num(void)
+void send_msg(enum msgcode code, char *buf, int len)
 {
-	struct redo_list *next;
-	int num;
+	if (msg_fd_out < 0) {
+		io_multiplex_write(code, buf, len);
+		return;
+	}
+	msg_list_add(code, buf, len);
+	msg_list_flush(NORMAL_FLUSH);
+}
 
-	while (!redo_list_head)
+int get_redo_num(int itemizing, enum logcode code)
+{
+	while (1) {
+		if (hlink_list.head)
+			check_for_finished_hlinks(itemizing, code);
+		if (redo_list.head)
+			break;
 		read_msg_fd();
+	}
 
-	num = redo_list_head->num;
-	next = redo_list_head->next;
-	free(redo_list_head);
-	redo_list_head = next;
-	if (!next)
-		redo_list_tail = NULL;
+	return flist_ndx_pop(&redo_list);
+}
 
-	return num;
+int get_hlink_num(void)
+{
+	return flist_ndx_pop(&hlink_list);
 }
 
 /**
@@ -364,22 +414,26 @@ void io_set_filesfrom_fds(int f_in, int f_out)
 	io_filesfrom_buflen = 0;
 }
 
-/**
- * It's almost always an error to get an EOF when we're trying to read
- * from the network, because the protocol is self-terminating.
+/* It's almost always an error to get an EOF when we're trying to read from the
+ * network, because the protocol is (for the most part) self-terminating.
  *
- * However, there is one unfortunate cases where it is not, which is
- * rsync <2.4.6 sending a list of modules on a server, since the list
- * is terminated by closing the socket. So, for the section of the
- * program where that is a problem (start_socket_client),
- * kluge_around_eof is True and we just exit.
- */
+ * There is one case for the receiver when it is at the end of the transfer
+ * (hanging around reading any keep-alive packets that might come its way): if
+ * the sender dies before the generator's kill-signal comes through, we can end
+ * up here needing to loop until the kill-signal arrives.  In this situation,
+ * kluge_around_eof will be < 0.
+ *
+ * There is another case for older protocol versions (< 24) where the module
+ * listing was not terminated, so we must ignore an EOF error in that case and
+ * exit.  In this situation, kluge_around_eof will be > 0. */
 static void whine_about_eof(int fd)
 {
 	if (kluge_around_eof && fd == sock_f_in) {
+		int i;
 		if (kluge_around_eof > 0)
 			exit_cleanup(0);
-		while (1)
+		/* If we're still here after 10 seconds, exit with an error. */
+		for (i = 10*1000/20; i--; )
 			msleep(20);
 	}
 
@@ -390,7 +444,6 @@ static void whine_about_eof(int fd)
 	exit_cleanup(RERR_STREAMIO);
 }
 
-
 /**
  * Read from a socket with I/O timeout. return the number of bytes
  * read. If no bytes can be read then exit, never return a number <= 0.
@@ -404,11 +457,11 @@ static void whine_about_eof(int fd)
  */
 static int read_timeout(int fd, char *buf, size_t len)
 {
-	int n, ret = 0;
+	int n, cnt = 0;
 
 	io_flush(NORMAL_FLUSH);
 
-	while (ret == 0) {
+	while (cnt == 0) {
 		/* until we manage to read *something* */
 		fd_set r_fds, w_fds;
 		struct timeval tv;
@@ -418,11 +471,7 @@ static int read_timeout(int fd, char *buf, size_t len)
 		FD_ZERO(&r_fds);
 		FD_ZERO(&w_fds);
 		FD_SET(fd, &r_fds);
-		if (msg_fd_in >= 0) {
-			FD_SET(msg_fd_in, &r_fds);
-			if (msg_fd_in > maxfd)
-				maxfd = msg_fd_in;
-		} else if (msg_list_head) {
+		if (msg_list.head) {
 			FD_SET(msg_fd_out, &w_fds);
 			if (msg_fd_out > maxfd)
 				maxfd = msg_fd_out;
@@ -459,10 +508,8 @@ static int read_timeout(int fd, char *buf, size_t len)
 			continue;
 		}
 
-		if (msg_fd_in >= 0 && FD_ISSET(msg_fd_in, &r_fds))
-			read_msg_fd();
-		else if (msg_list_head && FD_ISSET(msg_fd_out, &w_fds))
-			msg_list_push(NORMAL_FLUSH);
+		if (msg_list.head && FD_ISSET(msg_fd_out, &w_fds))
+			msg_list_flush(NORMAL_FLUSH);
 
 		if (io_filesfrom_f_out >= 0) {
 			if (io_filesfrom_buflen) {
@@ -540,21 +587,23 @@ static int read_timeout(int fd, char *buf, size_t len)
 				continue;
 
 			/* Don't write errors on a dead socket. */
-			if (fd == sock_f_in)
+			if (fd == sock_f_in) {
 				close_multiplexing_out();
-			rsyserr(FERROR, errno, "read error");
+				rsyserr(FSOCKERR, errno, "read error");
+			} else
+				rsyserr(FERROR, errno, "read error");
 			exit_cleanup(RERR_STREAMIO);
 		}
 
 		buf += n;
 		len -= n;
-		ret += n;
+		cnt += n;
 
-		if (io_timeout && fd == sock_f_in)
-			last_io = time(NULL);
+		if (fd == sock_f_in && io_timeout)
+			last_io_in = time(NULL);
 	}
 
-	return ret;
+	return cnt;
 }
 
 /**
@@ -565,7 +614,7 @@ int read_filesfrom_line(int fd, char *fname)
 {
 	char ch, *s, *eob = fname + MAXPATHLEN - 1;
 	int cnt;
-	int reading_remotely = remote_filesfrom_file != NULL;
+	int reading_remotely = filesfrom_host != NULL;
 	int nulls = eol_nulls || reading_remotely;
 
   start:
@@ -604,7 +653,6 @@ int read_filesfrom_line(int fd, char *fname)
 	return s - fname;
 }
 
-
 static char *iobuf_out;
 static int iobuf_out_cnt;
 
@@ -617,7 +665,6 @@ void io_start_buffering_out(void)
 	iobuf_out_cnt = 0;
 }
 
-
 static char *iobuf_in;
 static size_t iobuf_in_siz;
 
@@ -630,7 +677,6 @@ void io_start_buffering_in(void)
 		out_of_memory("io_start_buffering_in");
 }
 
-
 void io_end_buffering(void)
 {
 	io_flush(NORMAL_FLUSH);
@@ -640,14 +686,19 @@ void io_end_buffering(void)
 	}
 }
 
+void maybe_flush_socket(void)
+{
+	if (iobuf_out && iobuf_out_cnt && time(NULL) - last_io_out >= 5)
+		io_flush(NORMAL_FLUSH);
+}
 
-void maybe_send_keepalive(int allowed_lull, int ndx)
+void maybe_send_keepalive(void)
 {
-	if (time(NULL) - last_io >= allowed_lull) {
+	if (time(NULL) - last_io_out >= allowed_lull) {
 		if (!iobuf_out || !iobuf_out_cnt) {
 			if (protocol_version < 29)
 				return; /* there's nothing we can do */
-			write_int(sock_f_out, ndx);
+			write_int(sock_f_out, the_file_list->count);
 			write_shortint(sock_f_out, ITEM_IS_NEW);
 		}
 		if (iobuf_out)
@@ -655,7 +706,6 @@ void maybe_send_keepalive(int allowed_lull, int ndx)
 	}
 }
 
-
 /**
  * Continue trying to read len bytes - don't return until len has been
  * read.
@@ -670,7 +720,6 @@ static void read_loop(int fd, char *buf, size_t len)
 	}
 }
 
-
 /**
  * Read from the file descriptor handling multiplexing - return number
  * of bytes read.
@@ -681,8 +730,9 @@ static int readfd_unbuffered(int fd, char *buf, size_t len)
 {
 	static size_t remaining;
 	static size_t iobuf_in_ndx;
-	int tag, ret = 0;
-	char line[MAXPATHLEN+1];
+	size_t msg_bytes;
+	int tag, cnt = 0;
+	char line[BIGPATHBUFLEN];
 
 	if (!iobuf_in || fd != sock_f_in)
 		return read_timeout(fd, buf, len);
@@ -692,73 +742,70 @@ static int readfd_unbuffered(int fd, char *buf, size_t len)
 		iobuf_in_ndx = 0;
 	}
 
-	while (ret == 0) {
+	while (cnt == 0) {
 		if (remaining) {
 			len = MIN(len, remaining);
 			memcpy(buf, iobuf_in + iobuf_in_ndx, len);
 			iobuf_in_ndx += len;
 			remaining -= len;
-			ret = len;
+			cnt = len;
 			break;
 		}
 
 		read_loop(fd, line, 4);
 		tag = IVAL(line, 0);
 
-		remaining = tag & 0xFFFFFF;
+		msg_bytes = tag & 0xFFFFFF;
 		tag = (tag >> 24) - MPLEX_BASE;
 
 		switch (tag) {
 		case MSG_DATA:
-			if (remaining > iobuf_in_siz) {
+			if (msg_bytes > iobuf_in_siz) {
 				if (!(iobuf_in = realloc_array(iobuf_in, char,
-							       remaining)))
+							       msg_bytes)))
 					out_of_memory("readfd_unbuffered");
-				iobuf_in_siz = remaining;
+				iobuf_in_siz = msg_bytes;
 			}
-			read_loop(fd, iobuf_in, remaining);
+			read_loop(fd, iobuf_in, msg_bytes);
+			remaining = msg_bytes;
 			iobuf_in_ndx = 0;
 			break;
 		case MSG_DELETED:
-			if (remaining >= sizeof line) {
-				rprintf(FERROR, "invalid multi-message %d:%ld\n",
-					tag, (long)remaining);
-				exit_cleanup(RERR_STREAMIO);
-			}
-			read_loop(fd, line, remaining);
-			line[remaining] = '\0';
+			if (msg_bytes >= sizeof line)
+				goto overflow;
+			read_loop(fd, line, msg_bytes);
 			/* A directory name was sent with the trailing null */
-			if (remaining > 0 && !line[remaining-1])
+			if (msg_bytes > 0 && !line[msg_bytes-1])
 				log_delete(line, S_IFDIR);
-			else
+			else {
+				line[msg_bytes] = '\0';
 				log_delete(line, S_IFREG);
-			remaining = 0;
+			}
 			break;
 		case MSG_SUCCESS:
-			if (remaining != 4) {
-				rprintf(FERROR, "invalid multi-message %d:%ld\n",
-					tag, (long)remaining);
+			if (msg_bytes != 4) {
+				rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
+					tag, (long)msg_bytes, who_am_i());
 				exit_cleanup(RERR_STREAMIO);
 			}
-			read_loop(fd, line, remaining);
+			read_loop(fd, line, msg_bytes);
 			successful_send(IVAL(line, 0));
-			remaining = 0;
 			break;
 		case MSG_INFO:
 		case MSG_ERROR:
-			if (remaining >= sizeof line) {
+			if (msg_bytes >= sizeof line) {
+			    overflow:
 				rprintf(FERROR,
-					"[%s] multiplexing overflow %d:%ld\n\n",
-					who_am_i(), tag, (long)remaining);
+					"multiplexing overflow %d:%ld [%s]\n",
+					tag, (long)msg_bytes, who_am_i());
 				exit_cleanup(RERR_STREAMIO);
 			}
-			read_loop(fd, line, remaining);
-			rwrite((enum logcode)tag, line, remaining);
-			remaining = 0;
+			read_loop(fd, line, msg_bytes);
+			rwrite((enum logcode)tag, line, msg_bytes);
 			break;
 		default:
-			rprintf(FERROR, "[%s] unexpected tag %d\n",
-				who_am_i(), tag);
+			rprintf(FERROR, "unexpected tag %d [%s]\n",
+				tag, who_am_i());
 			exit_cleanup(RERR_STREAMIO);
 		}
 	}
@@ -766,11 +813,9 @@ static int readfd_unbuffered(int fd, char *buf, size_t len)
 	if (remaining == 0)
 		io_flush(NORMAL_FLUSH);
 
-	return ret;
+	return cnt;
 }
 
-
-
 /**
  * Do a buffered read from @p fd.  Don't return until all @p n bytes
  * have been read.  If all @p n can't be read then exit with an
@@ -778,12 +823,12 @@ static int readfd_unbuffered(int fd, char *buf, size_t len)
  **/
 static void readfd(int fd, char *buffer, size_t N)
 {
-	int  ret;
+	int  cnt;
 	size_t total = 0;
 
 	while (total < N) {
-		ret = readfd_unbuffered(fd, buffer + total, N-total);
-		total += ret;
+		cnt = readfd_unbuffered(fd, buffer + total, N-total);
+		total += cnt;
 	}
 
 	if (fd == write_batch_monitor_in) {
@@ -795,7 +840,6 @@ static void readfd(int fd, char *buffer, size_t N)
 		stats.total_read += total;
 }
 
-
 int read_shortint(int f)
 {
 	uchar b[2];
@@ -803,37 +847,36 @@ int read_shortint(int f)
 	return (b[1] << 8) + b[0];
 }
 
-
 int32 read_int(int f)
 {
 	char b[4];
-	int32 ret;
+	int32 num;
 
 	readfd(f,b,4);
-	ret = IVAL(b,0);
-	if (ret == (int32)0xffffffff)
+	num = IVAL(b,0);
+	if (num == (int32)0xffffffff)
 		return -1;
-	return ret;
+	return num;
 }
 
 int64 read_longint(int f)
 {
-	int64 ret;
+	int64 num;
 	char b[8];
-	ret = read_int(f);
+	num = read_int(f);
 
-	if ((int32)ret != (int32)0xffffffff)
-		return ret;
+	if ((int32)num != (int32)0xffffffff)
+		return num;
 
 #if SIZEOF_INT64 < 8
 	rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
 	exit_cleanup(RERR_UNSUPPORTED);
 #else
 	readfd(f,b,8);
-	ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
+	num = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 #endif
 
-	return ret;
+	return num;
 }
 
 void read_buf(int f,char *buf,size_t len)
@@ -844,7 +887,7 @@ void read_buf(int f,char *buf,size_t len)
 void read_sbuf(int f,char *buf,size_t len)
 {
 	readfd(f, buf, len);
-	buf[len] = 0;
+	buf[len] = '\0';
 }
 
 uchar read_byte(int f)
@@ -854,6 +897,25 @@ uchar read_byte(int f)
 	return c;
 }
 
+int read_vstring(int f, char *buf, int bufsize)
+{
+	int len = read_byte(f);
+
+	if (len & 0x80)
+		len = (len & ~0x80) * 0x100 + read_byte(f);
+
+	if (len >= bufsize) {
+		rprintf(FERROR, "over-long vstring received (%d > %d)\n",
+			len, bufsize - 1);
+		return -1;
+	}
+
+	if (len)
+		readfd(f, buf, len);
+	buf[len] = '\0';
+	return len;
+}
+
 /* Populate a sum_struct with values from the socket.  This is
  * called by both the sender and the receiver. */
 void read_sum_head(int f, struct sum_struct *sum)
@@ -861,20 +923,20 @@ void read_sum_head(int f, struct sum_struct *sum)
 	sum->count = read_int(f);
 	sum->blength = read_int(f);
 	if (sum->blength < 0 || sum->blength > MAX_BLOCK_SIZE) {
-		rprintf(FERROR, "[%s] Invalid block length %ld\n",
-			who_am_i(), (long)sum->blength);
+		rprintf(FERROR, "Invalid block length %ld [%s]\n",
+			(long)sum->blength, who_am_i());
 		exit_cleanup(RERR_PROTOCOL);
 	}
 	sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
 	if (sum->s2length < 0 || sum->s2length > MD4_SUM_LENGTH) {
-		rprintf(FERROR, "[%s] Invalid checksum length %d\n",
-			who_am_i(), sum->s2length);
+		rprintf(FERROR, "Invalid checksum length %d [%s]\n",
+			sum->s2length, who_am_i());
 		exit_cleanup(RERR_PROTOCOL);
 	}
 	sum->remainder = read_int(f);
 	if (sum->remainder < 0 || sum->remainder > sum->blength) {
-		rprintf(FERROR, "[%s] Invalid remainder length %ld\n",
-			who_am_i(), (long)sum->remainder);
+		rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
+			(long)sum->remainder, who_am_i());
 		exit_cleanup(RERR_PROTOCOL);
 	}
 }
@@ -896,7 +958,6 @@ void write_sum_head(int f, struct sum_struct *sum)
 	write_int(f, sum->remainder);
 }
 
-
 /**
  * Sleep after writing to limit I/O bandwidth usage.
  *
@@ -952,10 +1013,9 @@ static void sleep_for_bwlimit(int bytes_written)
 	total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
 }
 
-
 /* Write len bytes to the file descriptor fd, looping as necessary to get
- * the job done and also (in the generator) reading any data on msg_fd_in
- * (to avoid deadlock).
+ * the job done and also (in certain circumstances) reading any data on
+ * msg_fd_in to avoid deadlock.
  *
  * This function underlies the multiplexing system.  The body of the
  * application never calls this function directly. */
@@ -963,7 +1023,7 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 {
 	size_t n, total = 0;
 	fd_set w_fds, r_fds;
-	int maxfd, count, ret;
+	int maxfd, count, cnt, using_r_fds;
 	struct timeval tv;
 
 	no_flush++;
@@ -973,23 +1033,20 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 		FD_SET(fd,&w_fds);
 		maxfd = fd;
 
-		if (msg_fd_in >= 0) {
+		if (msg_fd_in >= 0 && len-total >= contiguous_write_len) {
 			FD_ZERO(&r_fds);
 			FD_SET(msg_fd_in,&r_fds);
 			if (msg_fd_in > maxfd)
 				maxfd = msg_fd_in;
-		}
-		if (fd != sock_f_out && iobuf_out_cnt && no_flush == 1) {
-			FD_SET(sock_f_out, &w_fds);
-			if (sock_f_out > maxfd)
-				maxfd = sock_f_out;
-		}
+			using_r_fds = 1;
+		} else
+			using_r_fds = 0;
 
 		tv.tv_sec = select_timeout;
 		tv.tv_usec = 0;
 
 		errno = 0;
-		count = select(maxfd + 1, msg_fd_in >= 0 ? &r_fds : NULL,
+		count = select(maxfd + 1, using_r_fds ? &r_fds : NULL,
 			       &w_fds, NULL, &tv);
 
 		if (count <= 0) {
@@ -999,25 +1056,19 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 			continue;
 		}
 
-		if (msg_fd_in >= 0 && FD_ISSET(msg_fd_in, &r_fds))
+		if (using_r_fds && FD_ISSET(msg_fd_in, &r_fds))
 			read_msg_fd();
 
-		if (!FD_ISSET(fd, &w_fds)) {
-			if (fd != sock_f_out && iobuf_out_cnt) {
-				no_flush--;
-				io_flush(NORMAL_FLUSH);
-				no_flush++;
-			}
+		if (!FD_ISSET(fd, &w_fds))
 			continue;
-		}
 
 		n = len - total;
 		if (bwlimit && n > bwlimit_writemax)
 			n = bwlimit_writemax;
-		ret = write(fd, buf + total, n);
+		cnt = write(fd, buf + total, n);
 
-		if (ret <= 0) {
-			if (ret < 0) {
+		if (cnt <= 0) {
+			if (cnt < 0) {
 				if (errno == EINTR)
 					continue;
 				if (errno == EWOULDBLOCK || errno == EAGAIN) {
@@ -1035,7 +1086,7 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 			/* If the other side is sending us error messages, try
 			 * to grab any messages they sent before they died. */
 			while (fd == sock_f_out && io_multiplexing_in) {
-				io_timeout = select_timeout = 30;
+				set_io_timeout(30);
 				ignore_timeout = 0;
 				readfd_unbuffered(sock_f_in, io_filesfrom_buf,
 						  sizeof io_filesfrom_buf);
@@ -1043,34 +1094,41 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 			exit_cleanup(RERR_STREAMIO);
 		}
 
-		total += ret;
+		total += cnt;
 
 		if (fd == sock_f_out) {
-			if (io_timeout)
-				last_io = time(NULL);
-			sleep_for_bwlimit(ret);
+			if (io_timeout || am_generator)
+				last_io_out = time(NULL);
+			sleep_for_bwlimit(cnt);
 		}
 	}
 
 	no_flush--;
 }
 
-
 /**
  * Write an message to a multiplexed stream. If this fails then rsync
  * exits.
  **/
 static void mplex_write(enum msgcode code, char *buf, size_t len)
 {
-	char buffer[4096];
+	char buffer[1024];
 	size_t n = len;
 
 	SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
 
+	/* When the generator reads messages from the msg_fd_in pipe, it can
+	 * cause output to occur down the socket.  Setting contiguous_write_len
+	 * prevents the reading of msg_fd_in once we actually start to write
+	 * this sequence of data (though we might read it before the start). */
+	if (am_generator && msg_fd_in >= 0)
+		contiguous_write_len = len + 4;
+
 	if (n > sizeof buffer - 4)
-		n = sizeof buffer - 4;
+		n = 0;
+	else
+		memcpy(buffer + 4, buf, n);
 
-	memcpy(&buffer[4], buf, n);
 	writefd_unbuffered(sock_f_out, buffer, n+4);
 
 	len -= n;
@@ -1078,12 +1136,14 @@ static void mplex_write(enum msgcode code, char *buf, size_t len)
 
 	if (len)
 		writefd_unbuffered(sock_f_out, buf, len);
-}
 
+	if (am_generator && msg_fd_in >= 0)
+		contiguous_write_len = 0;
+}
 
 void io_flush(int flush_it_all)
 {
-	msg_list_push(flush_it_all);
+	msg_list_flush(flush_it_all);
 
 	if (!iobuf_out_cnt || no_flush)
 		return;
@@ -1095,7 +1155,6 @@ void io_flush(int flush_it_all)
 	iobuf_out_cnt = 0;
 }
 
-
 static void writefd(int fd,char *buf,size_t len)
 {
 	if (fd == msg_fd_out) {
@@ -1130,7 +1189,6 @@ static void writefd(int fd,char *buf,size_t len)
 	}
 }
 
-
 void write_shortint(int f, int x)
 {
 	uchar b[2];
@@ -1139,7 +1197,6 @@ void write_shortint(int f, int x)
 	writefd(f, (char *)b, 2);
 }
 
-
 void write_int(int f,int32 x)
 {
 	char b[4];
@@ -1147,7 +1204,6 @@ void write_int(int f,int32 x)
 	writefd(f,b,4);
 }
 
-
 void write_int_named(int f, int32 x, const char *phase)
 {
 	io_write_phase = phase;
@@ -1155,7 +1211,6 @@ void write_int_named(int f, int32 x, const char *phase)
 	io_write_phase = phase_unknown;
 }
 
-
 /*
  * Note: int64 may actually be a 32-bit type if ./configure couldn't find any
  * 64-bit types on this platform.
@@ -1186,19 +1241,36 @@ void write_buf(int f,char *buf,size_t len)
 	writefd(f,buf,len);
 }
 
-
 /** Write a string to the connection */
 void write_sbuf(int f, char *buf)
 {
 	writefd(f, buf, strlen(buf));
 }
 
-
 void write_byte(int f, uchar c)
 {
 	writefd(f, (char *)&c, 1);
 }
 
+void write_vstring(int f, char *str, int len)
+{
+	uchar lenbuf[3], *lb = lenbuf;
+
+	if (len > 0x7F) {
+		if (len > 0x7FFF) {
+			rprintf(FERROR,
+				"attempting to send over-long vstring (%d > %d)\n",
+				len, 0x7FFF);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+		*lb++ = len / 0x100 + 0x80;
+	}
+	*lb = len;
+
+	writefd(f, (char*)lenbuf, lb - lenbuf + 1);
+	if (len)
+		writefd(f, str, len);
+}
 
 /**
  * Read a line of up to @p maxlen characters into @p buf (not counting
@@ -1225,11 +1297,10 @@ int read_line(int f, char *buf, size_t maxlen)
 	return maxlen > 0;
 }
 
-
 void io_printf(int fd, const char *format, ...)
 {
 	va_list ap;
-	char buf[1024];
+	char buf[BIGPATHBUFLEN];
 	int len;
 
 	va_start(ap, format);
@@ -1239,10 +1310,14 @@ void io_printf(int fd, const char *format, ...)
 	if (len < 0)
 		exit_cleanup(RERR_STREAMIO);
 
+	if (len > (int)sizeof buf) {
+		rprintf(FERROR, "io_printf() was too long for the buffer.\n");
+		exit_cleanup(RERR_STREAMIO);
+	}
+
 	write_sbuf(fd, buf);
 }
 
-
 /** Setup for multiplexing a MSG_* stream with the data stream. */
 void io_start_multiplex_out(void)
 {