X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/aa3999d66c322bd60d8efd2af3056cc9659e1b4f..626b5ae839d240987059644321d38c963bd5a794:/io.c

diff --git a/io.c b/io.c
index 11015f5f..ae607756 100644
--- a/io.c
+++ b/io.c
@@ -39,6 +39,7 @@ extern size_t bwlimit_writemax;
 extern int io_timeout;
 extern int am_server;
 extern int am_sender;
+extern int am_receiver;
 extern int am_generator;
 extern int msgs2stderr;
 extern int inc_recurse;
@@ -64,11 +65,11 @@ extern iconv_t ic_send, ic_recv;
 
 int csum_length = SHORT_SUM_LENGTH; /* initial value */
 int allowed_lull = 0;
-int ignore_timeout = 0;
 int batch_fd = -1;
 int msgdone_cnt = 0;
 int forward_flist_data = 0;
 BOOL flist_receiving_enabled = False;
+BOOL we_send_keepalive_messages = False;
 
 /* Ignore an EOF error if non-zero. See whine_about_eof(). */
 int kluge_around_eof = 0;
@@ -152,25 +153,33 @@ static void read_a_msg(void);
 static void drain_multiplex_messages(void);
 static void sleep_for_bwlimit(int bytes_written);
 
-static void check_timeout(void)
+static void check_timeout(BOOL allow_keepalive)
 {
-	time_t t;
+	time_t t, chk;
 
-	if (!io_timeout || ignore_timeout)
+	/* On the receiving side, the generator is now handling timeouts, so
+	 * the receiver ignores them.  Note that the am_receiver flag is not
+	 * set until the receiver forks from the generator, so timeouts will be
+	 * based on receiving data on the receiving side until that event. */
+	if (!io_timeout || am_receiver)
 		return;
 
-	if (!last_io_in) {
-		last_io_in = time(NULL);
-		return;
+	t = time(NULL);
+
+	if (allow_keepalive && we_send_keepalive_messages) {
+		/* This may put data into iobuf.msg w/o flushing. */
+		maybe_send_keepalive(t, False);
 	}
 
-	t = time(NULL);
+	if (!last_io_in)
+		last_io_in = t;
 
-	if (t - last_io_in >= io_timeout) {
+	chk = MAX(last_io_out, last_io_in);
+	if (t - chk >= io_timeout) {
 		if (am_server)
 			msgs2stderr = 1;
 		rprintf(FERROR, "[%s] io timeout after %d seconds -- exiting\n",
-			who_am_i(), (int)(t-last_io_in));
+			who_am_i(), (int)(t-chk));
 		exit_cleanup(RERR_TIMEOUT);
 	}
 }
@@ -252,7 +261,8 @@ static size_t safe_read(int fd, char *buf, size_t len)
 					who_am_i());
 				exit_cleanup(RERR_FILEIO);
 			}
-			check_timeout();
+			if (we_send_keepalive_messages)
+				maybe_send_keepalive(time(NULL), True);
 			continue;
 		}
 
@@ -336,7 +346,8 @@ static void safe_write(int fd, const char *buf, size_t len)
 					what_fd_is(fd), who_am_i());
 				exit_cleanup(RERR_FILEIO);
 			}
-			check_timeout();
+			if (we_send_keepalive_messages)
+				maybe_send_keepalive(time(NULL), True);
 			continue;
 		}
 
@@ -489,23 +500,25 @@ void restore_iobuf_size(xbuf *out)
 	}
 }
 
-/* Perform buffered input and output until specified conditions are met.  When
- * given a "needed" read requirement, we'll return without doing any I/O if the
- * iobuf.in bytes are already available.  When reading, we'll read as many
- * bytes as we can into the buffer, and return as soon as we meet the minimum
- * read requirement.  When given a "needed" write requirement, we'll return
- * without doing any I/O if that many bytes will fit in the output buffer (we
- * check either iobuf.out or iobuf.msg, depending on the flags).  When writing,
- * we write out as much as we can, and return as soon as the given free-space
- * requirement is available.
+/* Perform buffered input and/or output until specified conditions are met.
+ * When given a "needed" read or write request, this returns without doing any
+ * I/O if the needed input bytes or write space is already available.  Once I/O
+ * is needed, this will try to do whatever reading and/or writing is currently
+ * possible, up to the maximum buffer allowances, no matter if this is a read
+ * or write request.  However, the I/O stops as soon as the required input
+ * bytes or output space is available.  If this is not a read request, the
+ * routine may also do some advantageous reading of messages from a multiplexed
+ * input source (which ensures that we don't jam up with everyone in their
+ * "need to write" code and nobody reading the accumulated data that would make
+ * writing possible).
  *
- * The iobuf.out and iobuf.msg buffers are circular, so some writes into them
- * will need to be split when the data needs to wrap around to the start.  In
- * order to help make this easier for some operations (such as the use of
- * SIVAL() into the buffer) a buffer may be temporarily shortened, but the
- * original size will be automatically restored.  The iobuf.in buffer is also
- * circular, so callers may need to split their reading of the data if it spans
- * the end.  See also the 3 raw_* iobuf vars that are used in the handling of
+ * The iobuf.in, .out and .msg buffers are all circular.  Callers need to be
+ * aware that some data copies will need to be split when the bytes wrap around
+ * from the end to the start.  In order to help make writing into the output
+ * buffers easier for some operations (such as the use of SIVAL() into the
+ * buffer) a buffer may be temporarily shortened by a small amount, but the
+ * original size will be automatically restored when the .pos wraps to the
+ * start.  See also the 3 raw_* iobuf vars that are used in the handling of
  * MSG_DATA bytes as they are read-from/written-into the buffers.
  *
  * When writing, we flush data in the following priority order:
@@ -731,7 +744,7 @@ static char *perform_io(size_t needed, int flags)
 				send_extra_file_list(sock_f_out, -1);
 				extra_flist_sending_enabled = !flist_eof;
 			} else
-				check_timeout();
+				check_timeout((flags & PIO_NEED_INPUT) != 0);
 			FD_ZERO(&r_fds); /* Just in case... */
 			FD_ZERO(&w_fds);
 		}
@@ -1313,18 +1326,21 @@ void maybe_flush_socket(int important)
 		io_flush(NORMAL_FLUSH);
 }
 
-/* This never adds new non-msg-buffer data, since we don't know the state
- * of the raw-data buffer. */
-void maybe_send_keepalive(void)
-{
-	if (time(NULL) - last_io_out >= allowed_lull) {
-		if (!iobuf.msg.len && iobuf.out.len == iobuf.out_empty_len) {
-			if (protocol_version >= 30)
-				send_msg(MSG_NOOP, "", 0, 0);
-			else
-				send_msg(MSG_DATA, "", 0, 0);
-		}
-		if (iobuf.msg.len)
+/* Older rsync versions used to send either a MSG_NOOP (protocol 30) or a
+ * raw-data-based keep-alive (protocol 29), both of which implied forwarding of
+ * the message through the sender.  Since the new timeout method does not need
+ * any forwarding, we just send an empty MSG_DATA message, which works with all
+ * rsync versions.  This avoids any message forwarding, and leaves the raw-data
+ * stream alone (since we can never be quite sure if that stream is in the
+ * right state for a keep-alive message). */
+void maybe_send_keepalive(time_t now, BOOL allow_flush)
+{
+	if (now - last_io_out >= allowed_lull) {
+		if (!iobuf.msg.len && iobuf.out.len == iobuf.out_empty_len)
+			send_msg(MSG_DATA, "", 0, 0);
+		if (!allow_flush) {
+			/* Let the caller worry about writing out the data. */
+		} else if (iobuf.msg.len)
 			perform_io(iobuf.msg.size - iobuf.msg.len + 1, PIO_NEED_MSGROOM);
 		else if (iobuf.out.len > iobuf.out_empty_len)
 			io_flush(NORMAL_FLUSH);
@@ -1370,7 +1386,7 @@ static void read_a_msg(void)
 		 * the buffer the msg data will end once it is read.  It is
 		 * possible that this points off the end of the buffer, in
 		 * which case the gradual reading of the input stream will
-		 * cause this value to decrease and eventually become real. */
+		 * cause this value to wrap around and eventually become real. */
 		if (msg_bytes)
 			iobuf.raw_input_ends_before = iobuf.in.pos + msg_bytes;
 		iobuf.in_multiplexed = 1;
@@ -1409,11 +1425,12 @@ static void read_a_msg(void)
 		}
 		break;
 	case MSG_NOOP:
+		/* Support protocol-30 keep-alive method. */
 		if (msg_bytes != 0)
 			goto invalid_msg;
 		iobuf.in_multiplexed = 1;
 		if (am_sender)
-			maybe_send_keepalive();
+			maybe_send_keepalive(time(NULL), True);
 		break;
 	case MSG_DELETED:
 		if (msg_bytes >= sizeof data)