}
}
-/* 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:
read_buf(iobuf.in_fd, buf, sizeof buf);
}
-/* Buffer a message for the multiplexed output stream. Is never used for MSG_DATA. */
+/* Buffer a message for the multiplexed output stream. Is not used for (normal) MSG_DATA. */
int send_msg(enum msgcode code, const char *buf, size_t len, int convert)
{
char *hdr;
{
size_t siz;
- if ((pos += 4) >= iobuf.msg.size)
- pos -= iobuf.msg.size;
+ if ((pos += 4) == iobuf.msg.size)
+ pos = 0;
/* Handle a split copy if we wrap around the end of the circular buffer. */
if (pos >= iobuf.msg.pos && (siz = iobuf.msg.size - pos) < len) {
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 < 29)
- return; /* there's nothing we can do */
if (protocol_version >= 30)
send_msg(MSG_NOOP, "", 0, 0);
- else {
- write_int(iobuf.out_fd, cur_flist->used);
- write_shortint(iobuf.out_fd, ITEM_IS_NEW);
- }
+ else
+ send_msg(MSG_DATA, "", 0, 0);
}
if (iobuf.msg.len)
perform_io(iobuf.msg.size - iobuf.msg.len + 1, PIO_NEED_MSGROOM);
* 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. */
- iobuf.raw_input_ends_before = iobuf.in.pos + msg_bytes;
+ * 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;
break;
case MSG_STATS:
}
break;
case MSG_NOOP:
+ if (msg_bytes != 0)
+ goto invalid_msg;
+ iobuf.in_multiplexed = 1;
if (am_sender)
maybe_send_keepalive();
- iobuf.in_multiplexed = 1;
break;
case MSG_DELETED:
if (msg_bytes >= sizeof data)
send_msg(MSG_ERROR_EXIT, "", 0, 0);
io_flush(FULL_FLUSH);
}
- val = 0;
- } else {
- val = raw_read_int();
- if (protocol_version >= 31) {
- if (am_generator) {
- if (DEBUG_GTE(EXIT, 3)) {
- rprintf(FINFO, "[%s] sending MSG_ERROR_EXIT with exit_code %d\n",
- who_am_i(), val);
- }
- send_msg_int(MSG_ERROR_EXIT, val);
- } else {
- if (DEBUG_GTE(EXIT, 3)) {
- rprintf(FINFO, "[%s] sending MSG_ERROR_EXIT (len 0)\n",
- who_am_i());
- }
- send_msg(MSG_ERROR_EXIT, "", 0, 0);
+ } else if (protocol_version >= 31) {
+ if (am_generator) {
+ if (DEBUG_GTE(EXIT, 3)) {
+ rprintf(FINFO, "[%s] sending MSG_ERROR_EXIT with exit_code %d\n",
+ who_am_i(), val);
+ }
+ send_msg_int(MSG_ERROR_EXIT, val);
+ } else {
+ if (DEBUG_GTE(EXIT, 3)) {
+ rprintf(FINFO, "[%s] sending MSG_ERROR_EXIT (len 0)\n",
+ who_am_i());
}
+ send_msg(MSG_ERROR_EXIT, "", 0, 0);
}
}
/* Send a negative linenum so that we don't end up
Matt McCutchen's Web Site / rsync / rsync.git / blobdiff