Avoid calling send_extra_file_list() when we shouldn't.
[rsync/rsync.git] / io.c
diff --git a/io.c b/io.c
index 7cf272e..ce6495a 100644 (file)
--- a/io.c
+++ b/io.c
@@ -4,7 +4,7 @@
  * Copyright (C) 1996-2001 Andrew Tridgell
  * Copyright (C) 1996 Paul Mackerras
  * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
- * Copyright (C) 2003-2008 Wayne Davison
+ * Copyright (C) 2003-2009 Wayne Davison
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -29,6 +29,7 @@
 
 #include "rsync.h"
 #include "ifuncs.h"
+#include "inums.h"
 
 /** If no timeout is specified then use a 60 second select timeout */
 #define SELECT_TIMEOUT 60
@@ -44,6 +45,8 @@ extern int inc_recurse;
 extern int io_error;
 extern int eol_nulls;
 extern int flist_eof;
+extern int file_total;
+extern int file_old_total;
 extern int list_only;
 extern int read_batch;
 extern int protect_args;
@@ -51,6 +54,7 @@ extern int checksum_seed;
 extern int protocol_version;
 extern int remove_source_files;
 extern int preserve_hard_links;
+extern BOOL extra_flist_sending_enabled;
 extern struct stats stats;
 extern struct file_list *cur_flist;
 #ifdef ICONV_OPTION
@@ -100,7 +104,7 @@ static char ff_lastchar;
 #ifdef ICONV_OPTION
 static xbuf iconv_buf = EMPTY_XBUF;
 #endif
-static int defer_forwarding_messages = 0, defer_forwarding_keep = 0;
+static int defer_forwarding_messages = 0, keep_defer_forwarding = 0;
 static int select_timeout = SELECT_TIMEOUT;
 static int active_filecnt = 0;
 static OFF_T active_bytecnt = 0;
@@ -122,17 +126,9 @@ static void readfd(int fd, char *buffer, size_t N);
 static void writefd(int fd, const char *buf, size_t len);
 static void writefd_unbuffered(int fd, const char *buf, size_t len);
 static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len, int convert);
+static void read_a_msg(int fd);
 
-struct flist_ndx_item {
-       struct flist_ndx_item *next;
-       int ndx;
-};
-
-struct flist_ndx_list {
-       struct flist_ndx_item *head, *tail;
-};
-
-static struct flist_ndx_list redo_list, hlink_list;
+static flist_ndx_list redo_list, hlink_list;
 
 struct msg_list_item {
        struct msg_list_item *next;
@@ -146,45 +142,10 @@ struct msg_list {
 
 static struct msg_list msg_queue;
 
-static void flist_ndx_push(struct flist_ndx_list *lp, int ndx)
-{
-       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
-               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 got_flist_entry_status(enum festatus status, const char *buf)
 {
        int ndx = IVAL(buf, 0);
-       struct file_list *flist = flist_for_ndx(ndx);
-
-       assert(flist != NULL);
+       struct file_list *flist = flist_for_ndx(ndx, "got_flist_entry_status");
 
        if (remove_source_files) {
                active_filecnt--;
@@ -207,6 +168,11 @@ static void got_flist_entry_status(enum festatus status, const char *buf)
                }
                break;
        case FES_REDO:
+               if (read_batch) {
+                       if (inc_recurse)
+                               flist->in_progress++;
+                       break;
+               }
                if (inc_recurse)
                        flist->to_redo++;
                flist_ndx_push(&redo_list, ndx);
@@ -295,33 +261,32 @@ static void msg_list_add(struct msg_list *lst, int code, const char *buf, int le
        lst->tail = m;
 }
 
+static inline int flush_a_msg(int fd)
+{
+       struct msg_list_item *m = msg_queue.head;
+       int len = IVAL(m->buf, 0) & 0xFFFFFF;
+       int tag = *((uchar*)m->buf+3) - MPLEX_BASE;
+
+       if (!(msg_queue.head = m->next))
+               msg_queue.tail = NULL;
+
+       defer_forwarding_messages++;
+       mplex_write(fd, tag, m->buf + 4, len, m->convert);
+       defer_forwarding_messages--;
+
+       free(m);
+
+       return len;
+}
+
 static void msg_flush(void)
 {
        if (am_generator) {
-               while (msg_queue.head && io_multiplexing_out) {
-                       struct msg_list_item *m = msg_queue.head;
-                       int len = IVAL(m->buf, 0) & 0xFFFFFF;
-                       int tag = *((uchar*)m->buf+3) - MPLEX_BASE;
-                       if (!(msg_queue.head = m->next))
-                               msg_queue.tail = NULL;
-                       stats.total_written += len + 4;
-                       defer_forwarding_messages++;
-                       mplex_write(sock_f_out, tag, m->buf + 4, len, m->convert);
-                       defer_forwarding_messages--;
-                       free(m);
-               }
+               while (msg_queue.head && io_multiplexing_out)
+                       stats.total_written += flush_a_msg(sock_f_out) + 4;
        } else {
-               while (msg_queue.head) {
-                       struct msg_list_item *m = msg_queue.head;
-                       int len = IVAL(m->buf, 0) & 0xFFFFFF;
-                       int tag = *((uchar*)m->buf+3) - MPLEX_BASE;
-                       if (!(msg_queue.head = m->next))
-                               msg_queue.tail = NULL;
-                       defer_forwarding_messages++;
-                       mplex_write(msg_fd_out, tag, m->buf + 4, len, m->convert);
-                       defer_forwarding_messages--;
-                       free(m);
-               }
+               while (msg_queue.head)
+                       (void)flush_a_msg(msg_fd_out);
        }
 }
 
@@ -355,143 +320,23 @@ static void check_for_d_option_error(const char *msg)
        }
 }
 
-/* Read a message from the MSG_* fd and handle it.  This is called either
- * 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 the receiver). */
-static void read_msg_fd(void)
-{
-       char buf[2048];
-       size_t n;
-       struct file_list *flist;
-       int fd = msg_fd_in;
-       int tag, len;
-
-       /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
-        * to this routine from writefd_unbuffered(). */
-       no_flush++;
-       msg_fd_in = -1;
-       defer_forwarding_messages++;
-
-       readfd(fd, buf, 4);
-       tag = IVAL(buf, 0);
-
-       len = tag & 0xFFFFFF;
-       tag = (tag >> 24) - MPLEX_BASE;
-
-       switch (tag) {
-       case MSG_DONE:
-               if (len < 0 || len > 1 || !am_generator) {
-                 invalid_msg:
-                       rprintf(FERROR, "invalid message %d:%d [%s%s]\n",
-                               tag, len, who_am_i(),
-                               inc_recurse ? "/inc" : "");
-                       exit_cleanup(RERR_STREAMIO);
-               }
-               if (len) {
-                       readfd(fd, buf, len);
-                       stats.total_read = read_varlong(fd, 3);
-               }
-               msgdone_cnt++;
-               break;
-       case MSG_REDO:
-               if (len != 4 || !am_generator)
-                       goto invalid_msg;
-               readfd(fd, buf, 4);
-               got_flist_entry_status(FES_REDO, buf);
-               break;
-       case MSG_FLIST:
-               if (len != 4 || !am_generator || !inc_recurse)
-                       goto invalid_msg;
-               readfd(fd, buf, 4);
-               /* Read extra file list from receiver. */
-               assert(iobuf_in != NULL);
-               assert(iobuf_f_in == fd);
-               if (DEBUG_GTE(FLIST, 2)) {
-                       rprintf(FINFO, "[%s] receiving flist for dir %d\n",
-                               who_am_i(), IVAL(buf,0));
-               }
-               flist = recv_file_list(fd);
-               flist->parent_ndx = IVAL(buf,0);
-#ifdef SUPPORT_HARD_LINKS
-               if (preserve_hard_links)
-                       match_hard_links(flist);
-#endif
-               break;
-       case MSG_FLIST_EOF:
-               if (len != 0 || !am_generator || !inc_recurse)
-                       goto invalid_msg;
-               flist_eof = 1;
-               break;
-       case MSG_IO_ERROR:
-               if (len != 4)
-                       goto invalid_msg;
-               readfd(fd, buf, len);
-               io_error |= IVAL(buf, 0);
-               break;
-       case MSG_DELETED:
-               if (len >= (int)sizeof buf || !am_generator)
-                       goto invalid_msg;
-               readfd(fd, buf, len);
-               send_msg(MSG_DELETED, buf, len, 1);
-               break;
-       case MSG_SUCCESS:
-               if (len != 4 || !am_generator)
-                       goto invalid_msg;
-               readfd(fd, buf, 4);
-               got_flist_entry_status(FES_SUCCESS, buf);
-               break;
-       case MSG_NO_SEND:
-               if (len != 4 || !am_generator)
-                       goto invalid_msg;
-               readfd(fd, buf, 4);
-               got_flist_entry_status(FES_NO_SEND, buf);
-               break;
-       case MSG_ERROR_SOCKET:
-       case MSG_CLIENT:
-               if (!am_generator)
-                       goto invalid_msg;
-               if (tag == MSG_ERROR_SOCKET)
-                       io_end_multiplex_out();
-               /* FALL THROUGH */
-       case MSG_INFO:
-       case MSG_ERROR:
-       case MSG_ERROR_XFER:
-       case MSG_WARNING:
-       case MSG_LOG:
-               while (len) {
-                       n = len;
-                       if (n >= sizeof buf)
-                               n = sizeof buf - 1;
-                       readfd(fd, buf, n);
-                       rwrite((enum logcode)tag, buf, n, !am_generator);
-                       len -= n;
-               }
-               break;
-       default:
-               rprintf(FERROR, "unknown message %d:%d [%s]\n",
-                       tag, len, who_am_i());
-               exit_cleanup(RERR_STREAMIO);
-       }
-
-       no_flush--;
-       msg_fd_in = fd;
-       if (!--defer_forwarding_messages && !no_flush)
-               msg_flush();
-}
-
 /* This is used by the generator to limit how many file transfers can
  * be active at once when --remove-source-files is specified.  Without
  * this, sender-side deletions were mostly happening at the end. */
 void increment_active_files(int ndx, int itemizing, enum logcode code)
 {
-       /* TODO: tune these limits? */
-       while (active_filecnt >= (active_bytecnt >= 128*1024 ? 10 : 50)) {
+       while (1) {
+               /* TODO: tune these limits? */
+               int limit = active_bytecnt >= 128*1024 ? 10 : 50;
+               if (active_filecnt < limit)
+                       break;
                check_for_finished_files(itemizing, code, 0);
+               if (active_filecnt < limit)
+                       break;
                if (iobuf_out_cnt)
                        io_flush(NORMAL_FLUSH);
                else
-                       read_msg_fd();
+                       read_a_msg(msg_fd_in);
        }
 
        active_filecnt++;
@@ -511,7 +356,7 @@ static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len,
                xbuf outbuf, inbuf;
 
                INIT_XBUF(outbuf, buffer + 4, 0, sizeof buffer - 4);
-               INIT_XBUF(inbuf, (char*)buf, len, -1);
+               INIT_XBUF(inbuf, (char*)buf, len, (size_t)-1);
 
                iconvbufs(ic_send, &inbuf, &outbuf,
                          ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE);
@@ -530,9 +375,9 @@ static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len,
 
        SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
 
-       defer_forwarding_keep = 1; /* defer_forwarding_messages++ on return */
+       keep_defer_forwarding++; /* defer_forwarding_messages++ on return */
        writefd_unbuffered(fd, buffer, n+4);
-       defer_forwarding_keep = 0;
+       keep_defer_forwarding--;
 
        if (len > n)
                writefd_unbuffered(fd, buf+n, len-n);
@@ -551,7 +396,7 @@ int send_msg(enum msgcode code, const char *buf, int len, int convert)
                msg_list_add(&msg_queue, code, buf, len, convert);
                return 1;
        }
-       if (flist_forward_from >= 0)
+       if (defer_forwarding_messages)
                msg_list_add(&msg_queue, code, buf, len, convert);
        else
                mplex_write(msg_fd_out, code, buf, len, convert);
@@ -567,10 +412,9 @@ void send_msg_int(enum msgcode code, int num)
 
 void wait_for_receiver(void)
 {
-       if (iobuf_out_cnt)
-               io_flush(NORMAL_FLUSH);
-       else
-               read_msg_fd();
+       if (io_flush(FULL_FLUSH))
+               return;
+       read_a_msg(msg_fd_in);
 }
 
 int get_redo_num(void)
@@ -629,13 +473,12 @@ static void whine_about_eof(int fd)
 
        rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
                "(%s bytes received so far) [%s]\n",
-               big_num(stats.total_read, 0), who_am_i());
+               big_num(stats.total_read), who_am_i());
 
        exit_cleanup(RERR_STREAMIO);
 }
 
-/**
- * Read from a socket with I/O timeout. return the number of bytes
+/* 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.
  *
  * TODO: If the remote shell connection fails, then current versions
@@ -643,8 +486,7 @@ static void whine_about_eof(int fd)
  * fairly common mistake to try to use rsh when ssh is required, we
  * should trap that: if we fail to read any data at all, we should
  * give a better explanation.  We can tell whether the connection has
- * started by looking e.g. at whether the remote version is known yet.
- */
+ * started by looking e.g. at whether the remote version is known yet. */
 static int read_timeout(int fd, char *buf, size_t len)
 {
        int n, cnt = 0;
@@ -679,7 +521,16 @@ static int read_timeout(int fd, char *buf, size_t len)
                                maxfd = new_fd;
                }
 
-               tv.tv_sec = select_timeout;
+               if (extra_flist_sending_enabled && !defer_forwarding_messages) {
+                       if (file_total - file_old_total < MAX_FILECNT_LOOKAHEAD
+                        && file_total - file_old_total >= MIN_FILECNT_LOOKAHEAD)
+                               tv.tv_sec = 0;
+                       else {
+                               extra_flist_sending_enabled = False;
+                               tv.tv_sec = select_timeout;
+                       }
+               } else
+                       tv.tv_sec = select_timeout;
                tv.tv_usec = 0;
 
                errno = 0;
@@ -691,7 +542,12 @@ static int read_timeout(int fd, char *buf, size_t len)
                                defer_forwarding_messages = 0;
                                exit_cleanup(RERR_SOCKETIO);
                        }
-                       check_timeout();
+                       if (extra_flist_sending_enabled && !defer_forwarding_messages) {
+                               extra_flist_sending_enabled = False;
+                               send_extra_file_list(sock_f_out, -1);
+                               extra_flist_sending_enabled = !flist_eof;
+                       } else
+                               check_timeout();
                        continue;
                }
 
@@ -780,13 +636,13 @@ static int read_timeout(int fd, char *buf, size_t len)
                if (n <= 0) {
                        if (n == 0)
                                whine_about_eof(fd); /* Doesn't return. */
-                       if (errno == EINTR || errno == EWOULDBLOCK
-                           || errno == EAGAIN)
+                       if (errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN)
                                continue;
 
                        /* Don't write errors on a dead socket. */
                        if (fd == sock_f_in) {
-                               io_end_multiplex_out();
+                               if (am_sender)
+                                       io_multiplexing_out = 0;
                                rsyserr(FERROR_SOCKET, errno, "read error");
                        } else
                                rsyserr(FERROR, errno, "read error");
@@ -1010,10 +866,8 @@ void stop_flist_forward()
        io_flush(FULL_FLUSH);
 }
 
-/**
- * Continue trying to read len bytes - don't return until len has been
- * read.
- **/
+/* Continue trying to read len bytes until all have been read.
+ * Used to read raw bytes from a multiplexed source. */
 static void read_loop(int fd, char *buf, size_t len)
 {
        while (len) {
@@ -1024,17 +878,209 @@ static void read_loop(int fd, char *buf, size_t len)
        }
 }
 
-/**
- * Read from the file descriptor handling multiplexing - return number
- * of bytes read.
- *
- * Never returns <= 0.
- */
-static int readfd_unbuffered(int fd, char *buf, size_t len)
+/* Read a message from a multiplexed source. */
+static void read_a_msg(int fd)
 {
-       size_t msg_bytes;
-       int tag, cnt = 0;
        char line[BIGPATHBUFLEN];
+       size_t msg_bytes;
+       int tag, flist_parent = -1, save_msg_fd_in = msg_fd_in;
+
+       /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
+        * to this routine from writefd_unbuffered(). */
+       msg_fd_in = -1;
+
+       read_loop(fd, line, 4);
+       tag = IVAL(line, 0);
+
+       msg_bytes = tag & 0xFFFFFF;
+       tag = (tag >> 24) - MPLEX_BASE;
+
+       no_flush++;
+
+       switch (tag) {
+       case MSG_DATA:
+               if (msg_bytes > iobuf_in_siz) {
+                       if (!(iobuf_in = realloc_array(iobuf_in, char, msg_bytes)))
+                               out_of_memory("read_a_msg");
+                       iobuf_in_siz = msg_bytes;
+               }
+               read_loop(fd, iobuf_in, msg_bytes);
+               iobuf_in_remaining = msg_bytes;
+               iobuf_in_ndx = 0;
+               break;
+       case MSG_DONE:
+               if (msg_bytes > 1 || !am_generator)
+                       goto invalid_msg;
+               if (msg_bytes) {
+                       read_loop(fd, line, 1);
+                       stats.total_read = read_varlong(fd, 3);
+               }
+               msgdone_cnt++;
+               break;
+       case MSG_REDO:
+               if (msg_bytes != 4 || !am_generator)
+                       goto invalid_msg;
+               read_loop(fd, line, 4);
+               got_flist_entry_status(FES_REDO, line);
+               break;
+       case MSG_FLIST:
+               if (msg_bytes != 4 || !am_generator || !inc_recurse)
+                       goto invalid_msg;
+               read_loop(fd, line, 4);
+               /* Read extra file list from receiver. */
+               if (DEBUG_GTE(FLIST, 2)) {
+                       rprintf(FINFO, "[%s] receiving flist for dir %d\n",
+                               who_am_i(), IVAL(line, 0));
+               }
+               flist_parent = IVAL(line, 0);
+               break;
+       case MSG_FLIST_EOF:
+               if (msg_bytes != 0 || !am_generator || !inc_recurse)
+                       goto invalid_msg;
+               flist_eof = 1;
+               break;
+       case MSG_IO_ERROR:
+               if (msg_bytes != 4 || am_sender)
+                       goto invalid_msg;
+               read_loop(fd, line, 4);
+               io_error |= IVAL(line, 0);
+               if (!am_generator)
+                       send_msg_int(MSG_IO_ERROR, IVAL(line, 0));
+               break;
+       case MSG_NOOP:
+               if (am_sender)
+                       maybe_send_keepalive();
+               break;
+       case MSG_DEL_STATS:
+               if (msg_bytes)
+                       goto invalid_msg;
+               read_del_stats(fd);
+               if (am_sender && am_server)
+                       write_del_stats(sock_f_out);
+               break;
+       case MSG_DELETED:
+               if (msg_bytes >= sizeof line)
+                       goto overflow;
+               if (am_generator) {
+                       read_loop(fd, line, msg_bytes);
+                       send_msg(MSG_DELETED, line, msg_bytes, 1);
+                       break;
+               }
+#ifdef ICONV_OPTION
+               if (ic_recv != (iconv_t)-1) {
+                       xbuf outbuf, inbuf;
+                       char ibuf[512];
+                       int add_null = 0;
+
+                       INIT_CONST_XBUF(outbuf, line);
+                       INIT_XBUF(inbuf, ibuf, 0, (size_t)-1);
+
+                       while (msg_bytes) {
+                               inbuf.len = msg_bytes > sizeof ibuf
+                                         ? sizeof ibuf : msg_bytes;
+                               read_loop(fd, inbuf.buf, inbuf.len);
+                               if (!(msg_bytes -= inbuf.len)
+                                && !ibuf[inbuf.len-1])
+                                       inbuf.len--, add_null = 1;
+                               if (iconvbufs(ic_send, &inbuf, &outbuf,
+                                   ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE) < 0)
+                                       goto overflow;
+                       }
+                       if (add_null) {
+                               if (outbuf.len == outbuf.size)
+                                       goto overflow;
+                               outbuf.buf[outbuf.len++] = '\0';
+                       }
+                       msg_bytes = outbuf.len;
+               } else
+#endif
+                       read_loop(fd, line, msg_bytes);
+               /* A directory name was sent with the trailing null */
+               if (msg_bytes > 0 && !line[msg_bytes-1])
+                       log_delete(line, S_IFDIR);
+               else {
+                       line[msg_bytes] = '\0';
+                       log_delete(line, S_IFREG);
+               }
+               break;
+       case MSG_SUCCESS:
+               if (msg_bytes != 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);
+               }
+               read_loop(fd, line, 4);
+               if (am_generator)
+                       got_flist_entry_status(FES_SUCCESS, line);
+               else
+                       successful_send(IVAL(line, 0));
+               break;
+       case MSG_NO_SEND:
+               if (msg_bytes != 4)
+                       goto invalid_msg;
+               read_loop(fd, line, 4);
+               if (am_generator)
+                       got_flist_entry_status(FES_NO_SEND, line);
+               else
+                       send_msg_int(MSG_NO_SEND, IVAL(line, 0));
+               break;
+       case MSG_ERROR_SOCKET:
+       case MSG_ERROR_UTF8:
+       case MSG_CLIENT:
+       case MSG_LOG:
+               if (!am_generator)
+                       goto invalid_msg;
+               if (tag == MSG_ERROR_SOCKET)
+                       io_multiplexing_out = 0;
+               /* FALL THROUGH */
+       case MSG_INFO:
+       case MSG_ERROR:
+       case MSG_ERROR_XFER:
+       case MSG_WARNING:
+               if (msg_bytes >= sizeof line) {
+                   overflow:
+                       rprintf(FERROR,
+                               "multiplexing overflow %d:%lu [%s%s]\n",
+                               tag, (unsigned long)msg_bytes, who_am_i(),
+                               inc_recurse ? "/inc" : "");
+                       exit_cleanup(RERR_STREAMIO);
+               }
+               read_loop(fd, line, msg_bytes);
+               rwrite((enum logcode)tag, line, msg_bytes, !am_generator);
+               if (first_message) {
+                       if (list_only && !am_sender && tag == 1) {
+                               line[msg_bytes] = '\0';
+                               check_for_d_option_error(line);
+                       }
+                       first_message = 0;
+               }
+               break;
+       default:
+               rprintf(FERROR, "unexpected tag %d [%s%s]\n",
+                       tag, who_am_i(), inc_recurse ? "/inc" : "");
+               exit_cleanup(RERR_STREAMIO);
+       }
+
+       msg_fd_in = save_msg_fd_in;
+       no_flush--;
+
+       if (flist_parent >= 0) {
+               struct file_list *flist = recv_file_list(fd);
+               flist->parent_ndx = flist_parent;
+#ifdef SUPPORT_HARD_LINKS
+               if (preserve_hard_links)
+                       match_hard_links(flist);
+#endif
+       }
+}
+
+/* Read from the file descriptor handling multiplexing and return the
+ * number of bytes read.  Never returns <= 0. */
+static int readfd_unbuffered(int fd, char *buf, size_t len)
+{
+       int cnt = 0;
 
        if (!iobuf_in || fd != iobuf_f_in)
                return read_timeout(fd, buf, len);
@@ -1053,120 +1099,7 @@ static int readfd_unbuffered(int fd, char *buf, size_t len)
                        cnt = len;
                        break;
                }
-
-               read_loop(fd, line, 4);
-               tag = IVAL(line, 0);
-
-               msg_bytes = tag & 0xFFFFFF;
-               tag = (tag >> 24) - MPLEX_BASE;
-
-               switch (tag) {
-               case MSG_DATA:
-                       if (msg_bytes > iobuf_in_siz) {
-                               if (!(iobuf_in = realloc_array(iobuf_in, char,
-                                                              msg_bytes)))
-                                       out_of_memory("readfd_unbuffered");
-                               iobuf_in_siz = msg_bytes;
-                       }
-                       read_loop(fd, iobuf_in, msg_bytes);
-                       iobuf_in_remaining = msg_bytes;
-                       iobuf_in_ndx = 0;
-                       break;
-               case MSG_NOOP:
-                       if (am_sender)
-                               maybe_send_keepalive();
-                       break;
-               case MSG_IO_ERROR:
-                       if (msg_bytes != 4)
-                               goto invalid_msg;
-                       read_loop(fd, line, msg_bytes);
-                       send_msg_int(MSG_IO_ERROR, IVAL(line, 0));
-                       io_error |= IVAL(line, 0);
-                       break;
-               case MSG_DELETED:
-                       if (msg_bytes >= sizeof line)
-                               goto overflow;
-#ifdef ICONV_OPTION
-                       if (ic_recv != (iconv_t)-1) {
-                               xbuf outbuf, inbuf;
-                               char ibuf[512];
-                               int add_null = 0;
-                               int pos = 0;
-
-                               INIT_CONST_XBUF(outbuf, line);
-                               INIT_XBUF(inbuf, ibuf, 0, -1);
-
-                               while (msg_bytes) {
-                                       inbuf.len = msg_bytes > sizeof ibuf
-                                                 ? sizeof ibuf : msg_bytes;
-                                       read_loop(fd, inbuf.buf, inbuf.len);
-                                       if (!(msg_bytes -= inbuf.len)
-                                        && !ibuf[inbuf.len-1])
-                                               inbuf.len--, add_null = 1;
-                                       if (iconvbufs(ic_send, &inbuf, &outbuf,
-                                           ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE) < 0)
-                                               goto overflow;
-                                       pos = -1;
-                               }
-                               if (add_null) {
-                                       if (outbuf.len == outbuf.size)
-                                               goto overflow;
-                                       outbuf.buf[outbuf.len++] = '\0';
-                               }
-                               msg_bytes = outbuf.len;
-                       } else
-#endif
-                               read_loop(fd, line, msg_bytes);
-                       /* A directory name was sent with the trailing null */
-                       if (msg_bytes > 0 && !line[msg_bytes-1])
-                               log_delete(line, S_IFDIR);
-                       else {
-                               line[msg_bytes] = '\0';
-                               log_delete(line, S_IFREG);
-                       }
-                       break;
-               case MSG_SUCCESS:
-                       if (msg_bytes != 4) {
-                         invalid_msg:
-                               rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
-                                       tag, (long)msg_bytes, who_am_i());
-                               exit_cleanup(RERR_STREAMIO);
-                       }
-                       read_loop(fd, line, msg_bytes);
-                       successful_send(IVAL(line, 0));
-                       break;
-               case MSG_NO_SEND:
-                       if (msg_bytes != 4)
-                               goto invalid_msg;
-                       read_loop(fd, line, msg_bytes);
-                       send_msg_int(MSG_NO_SEND, IVAL(line, 0));
-                       break;
-               case MSG_INFO:
-               case MSG_ERROR:
-               case MSG_ERROR_XFER:
-               case MSG_WARNING:
-                       if (msg_bytes >= sizeof line) {
-                           overflow:
-                               rprintf(FERROR,
-                                       "multiplexing overflow %d:%ld [%s]\n",
-                                       tag, (long)msg_bytes, who_am_i());
-                               exit_cleanup(RERR_STREAMIO);
-                       }
-                       read_loop(fd, line, msg_bytes);
-                       rwrite((enum logcode)tag, line, msg_bytes, 1);
-                       if (first_message) {
-                               if (list_only && !am_sender && tag == 1) {
-                                       line[msg_bytes] = '\0';
-                                       check_for_d_option_error(line);
-                               }
-                               first_message = 0;
-                       }
-                       break;
-               default:
-                       rprintf(FERROR, "unexpected tag %d [%s]\n",
-                               tag, who_am_i());
-                       exit_cleanup(RERR_STREAMIO);
-               }
+               read_a_msg(fd);
        }
 
        if (iobuf_in_remaining == 0)
@@ -1452,6 +1385,22 @@ static void sleep_for_bwlimit(int bytes_written)
        total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
 }
 
+static const char *what_fd_is(int fd)
+{
+       static char buf[20];
+
+       if (fd == sock_f_out)
+               return "socket";
+       else if (fd == msg_fd_out)
+               return "message fd";
+       else if (fd == batch_fd)
+               return "batch file";
+       else {
+               snprintf(buf, sizeof buf, "fd %d", fd);
+               return buf;
+       }
+}
+
 /* Write len bytes to the file descriptor fd, looping as necessary to get
  * the job done and also (in certain circumstances) reading any data on
  * msg_fd_in to avoid deadlock.
@@ -1476,7 +1425,7 @@ static void writefd_unbuffered(int fd, const char *buf, size_t len)
                FD_SET(fd, &e_fds);
                maxfd = fd;
 
-               if (msg_fd_in >= 0) {
+               if (msg_fd_in >= 0 && iobuf_in_remaining == 0) {
                        FD_ZERO(&r_fds);
                        FD_SET(msg_fd_in, &r_fds);
                        if (msg_fd_in > maxfd)
@@ -1503,7 +1452,7 @@ static void writefd_unbuffered(int fd, const char *buf, size_t len)
                        rprintf(FINFO, "select exception on fd %d\n", fd); */
 
                if (using_r_fds && FD_ISSET(msg_fd_in, &r_fds))
-                       read_msg_fd();
+                       read_a_msg(msg_fd_in);
 
                if (!FD_ISSET(fd, &w_fds))
                        continue;
@@ -1525,20 +1474,20 @@ static void writefd_unbuffered(int fd, const char *buf, size_t len)
 
                        /* Don't try to write errors back across the stream. */
                        if (fd == sock_f_out)
-                               io_end_multiplex_out();
+                               io_multiplexing_out = 0;
                        /* Don't try to write errors down a failing msg pipe. */
                        if (am_server && fd == msg_fd_out)
                                exit_cleanup(RERR_STREAMIO);
                        rsyserr(FERROR, errno,
-                               "writefd_unbuffered failed to write %ld bytes [%s]",
-                               (long)len, who_am_i());
+                               "writefd_unbuffered failed to write %ld bytes to %s [%s]",
+                               (long)len, what_fd_is(fd), who_am_i());
                        /* If the other side is sending us error messages, try
                         * to grab any messages they sent before they died. */
                        while (!am_server && fd == sock_f_out && io_multiplexing_in) {
                                char buf[1024];
                                set_io_timeout(30);
                                ignore_timeout = 0;
-                               readfd_unbuffered(sock_f_in, buf, sizeof buf);
+                               readfd_unbuffered(iobuf_f_in, buf, sizeof buf);
                        }
                        exit_cleanup(RERR_STREAMIO);
                }
@@ -1554,24 +1503,34 @@ static void writefd_unbuffered(int fd, const char *buf, size_t len)
        }
 
        no_flush--;
-       defer_inc -= defer_forwarding_keep;
+       if (keep_defer_forwarding)
+               defer_inc--;
        if (!(defer_forwarding_messages -= defer_inc) && !no_flush)
                msg_flush();
 }
 
-void io_flush(int flush_it_all)
+int io_flush(int flush_it_all)
 {
-       if (!iobuf_out_cnt || no_flush)
-               return;
+       int flushed_something = 0;
 
-       if (io_multiplexing_out)
-               mplex_write(sock_f_out, MSG_DATA, iobuf_out, iobuf_out_cnt, 0);
-       else
-               writefd_unbuffered(iobuf_f_out, iobuf_out, iobuf_out_cnt);
-       iobuf_out_cnt = 0;
+       if (no_flush)
+               return 0;
+
+       if (iobuf_out_cnt) {
+               if (io_multiplexing_out)
+                       mplex_write(iobuf_f_out, MSG_DATA, iobuf_out, iobuf_out_cnt, 0);
+               else
+                       writefd_unbuffered(iobuf_f_out, iobuf_out, iobuf_out_cnt);
+               iobuf_out_cnt = 0;
+               flushed_something = 1;
+       }
 
-       if (flush_it_all && !defer_forwarding_messages)
+       if (flush_it_all && !defer_forwarding_messages && msg_queue.head) {
                msg_flush();
+               flushed_something = 1;
+       }
+
+       return flushed_something;
 }
 
 static void writefd(int fd, const char *buf, size_t len)
@@ -1579,10 +1538,8 @@ static void writefd(int fd, const char *buf, size_t len)
        if (fd == sock_f_out)
                stats.total_written += len;
 
-       if (fd == write_batch_monitor_out) {
-               if ((size_t)write(batch_fd, buf, len) != len)
-                       exit_cleanup(RERR_FILEIO);
-       }
+       if (fd == write_batch_monitor_out)
+               writefd_unbuffered(batch_fd, buf, len);
 
        if (!iobuf_out || fd != iobuf_f_out) {
                writefd_unbuffered(fd, buf, len);
@@ -1858,18 +1815,18 @@ void io_printf(int fd, const char *format, ...)
 }
 
 /** Setup for multiplexing a MSG_* stream with the data stream. */
-void io_start_multiplex_out(void)
+void io_start_multiplex_out(int f)
 {
        io_flush(NORMAL_FLUSH);
-       io_start_buffering_out(sock_f_out);
+       io_start_buffering_out(f);
        io_multiplexing_out = 1;
 }
 
 /** Setup for multiplexing a MSG_* stream with the data stream. */
-void io_start_multiplex_in(void)
+void io_start_multiplex_in(int f)
 {
        io_flush(NORMAL_FLUSH);
-       io_start_buffering_in(sock_f_in);
+       io_start_buffering_in(f);
        io_multiplexing_in = 1;
 }
 
@@ -1880,7 +1837,7 @@ int io_multiplex_write(enum msgcode code, const char *buf, size_t len, int conve
                return 0;
        io_flush(NORMAL_FLUSH);
        stats.total_written += (len+4);
-       mplex_write(sock_f_out, code, buf, len, convert);
+       mplex_write(iobuf_f_out, code, buf, len, convert);
        return 1;
 }