X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/3eeac9bc7ed328b44ca4e49a6daa0fd272c1114c..5b986297479dcdb1151a92c393af2a3ecb6a74bc:/io.c

diff --git a/io.c b/io.c
index 42a6bf0c..0948416f 100644
--- a/io.c
+++ b/io.c
@@ -49,6 +49,7 @@ 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;
@@ -59,7 +60,6 @@ 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;
@@ -90,7 +90,8 @@ int sock_f_out = -1;
 
 static int io_multiplexing_out;
 static int io_multiplexing_in;
-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;
@@ -103,6 +104,9 @@ 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 int active_filecnt = 0;
+static OFF_T active_bytecnt = 0;
 
 static void read_loop(int fd, char *buf, size_t len);
 
@@ -117,14 +121,17 @@ struct flist_ndx_list {
 
 static struct flist_ndx_list redo_list, hlink_list;
 
-struct msg_list {
-	struct msg_list *next;
+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 flist_ndx_push(struct flist_ndx_list *lp, int ndx)
 {
@@ -166,17 +173,17 @@ 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);
 	}
@@ -190,6 +197,18 @@ 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
@@ -210,9 +229,9 @@ 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)))
+	if (!(ml = new(struct msg_list_item)))
 		out_of_memory("msg_list_add");
 	ml->next = NULL;
 	if (!(ml->buf = new_array(char, len+4)))
@@ -220,21 +239,11 @@ static void msg_list_add(int code, char *buf, int len)
 	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
@@ -272,6 +281,8 @@ static void read_msg_fd(void)
 			exit_cleanup(RERR_STREAMIO);
 		}
 		read_loop(fd, buf, 4);
+		if (remove_sent_files)
+			decrement_active_files(IVAL(buf,0));
 		flist_ndx_push(&redo_list, IVAL(buf,0));
 		break;
 	case MSG_DELETED:
@@ -288,11 +299,20 @@ static void read_msg_fd(void)
 			exit_cleanup(RERR_STREAMIO);
 		}
 		read_loop(fd, buf, len);
-		if (remove_sent_files)
+		if (remove_sent_files) {
+			decrement_active_files(IVAL(buf,0));
 			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:
@@ -313,10 +333,32 @@ static void read_msg_fd(void)
 	msg_fd_in = fd;
 }
 
+/* This is used by the generator to limit how many file transfers can
+ * be active at once when --remove-sent-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)) {
+		if (hlink_list.head)
+			check_for_finished_hlinks(itemizing, code);
+		read_msg_fd();
+	}
+
+	active_filecnt++;
+	active_bytecnt += the_file_list->files[ndx]->length;
+}
+
+void decrement_active_files(int ndx)
+{
+	active_filecnt--;
+	active_bytecnt -= the_file_list->files[ndx]->length;
+}
+
 /* 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;
@@ -325,8 +367,8 @@ 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)
@@ -343,9 +385,9 @@ 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;
 		}
@@ -353,6 +395,16 @@ int msg_list_push(int flush_it_all)
 	return 1;
 }
 
+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_flush(NORMAL_FLUSH);
+}
+
 int get_redo_num(int itemizing, enum logcode code)
 {
 	while (1) {
@@ -420,7 +472,6 @@ 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.
@@ -434,11 +485,11 @@ 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;
@@ -448,7 +499,7 @@ 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_list_head) {
+		if (msg_list.head) {
 			FD_SET(msg_fd_out, &w_fds);
 			if (msg_fd_out > maxfd)
 				maxfd = msg_fd_out;
@@ -485,8 +536,8 @@ static int read_timeout(int fd, char *buf, size_t len)
 			continue;
 		}
 
-		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) {
@@ -564,21 +615,23 @@ 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;
 }
 
 /**
@@ -628,7 +681,6 @@ int read_filesfrom_line(int fd, char *fname)
 	return s - fname;
 }
 
-
 static char *iobuf_out;
 static int iobuf_out_cnt;
 
@@ -641,7 +693,6 @@ void io_start_buffering_out(void)
 	iobuf_out_cnt = 0;
 }
 
-
 static char *iobuf_in;
 static size_t iobuf_in_siz;
 
@@ -654,7 +705,6 @@ void io_start_buffering_in(void)
 		out_of_memory("io_start_buffering_in");
 }
 
-
 void io_end_buffering(void)
 {
 	io_flush(NORMAL_FLUSH);
@@ -664,10 +714,15 @@ 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(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 */
@@ -679,7 +734,6 @@ void maybe_send_keepalive(void)
 	}
 }
 
-
 /**
  * Continue trying to read len bytes - don't return until len has been
  * read.
@@ -694,7 +748,6 @@ static void read_loop(int fd, char *buf, size_t len)
 	}
 }
 
-
 /**
  * Read from the file descriptor handling multiplexing - return number
  * of bytes read.
@@ -705,8 +758,9 @@ 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);
@@ -716,69 +770,66 @@ 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) {
+			if (msg_bytes != 4) {
 				rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
-					tag, (long)remaining, who_am_i());
+					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,
 					"multiplexing overflow %d:%ld [%s]\n",
-					tag, (long)remaining, who_am_i());
+					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, "unexpected tag %d [%s]\n",
@@ -790,11 +841,9 @@ 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
@@ -802,12 +851,12 @@ 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) {
@@ -819,7 +868,6 @@ static void readfd(int fd, char *buffer, size_t N)
 		stats.total_read += total;
 }
 
-
 int read_shortint(int f)
 {
 	uchar b[2];
@@ -827,37 +875,36 @@ 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)
@@ -939,7 +986,6 @@ void write_sum_head(int f, struct sum_struct *sum)
 	write_int(f, sum->remainder);
 }
 
-
 /**
  * Sleep after writing to limit I/O bandwidth usage.
  *
@@ -995,9 +1041,8 @@ 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 certain circumstnces) reading any data on
+ * 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
@@ -1006,7 +1051,7 @@ 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, using_r_fds;
+	int maxfd, count, cnt, using_r_fds;
 	struct timeval tv;
 
 	no_flush++;
@@ -1024,11 +1069,6 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 			using_r_fds = 1;
 		} else
 			using_r_fds = 0;
-		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;
-		}
 
 		tv.tv_sec = select_timeout;
 		tv.tv_usec = 0;
@@ -1053,10 +1093,10 @@ static void writefd_unbuffered(int fd,char *buf,size_t len)
 		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) {
@@ -1074,7 +1114,7 @@ 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);
@@ -1082,26 +1122,25 @@ 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);
@@ -1114,9 +1153,10 @@ static void mplex_write(enum msgcode code, char *buf, size_t len)
 		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;
@@ -1129,10 +1169,9 @@ static void mplex_write(enum msgcode code, char *buf, size_t len)
 		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;
@@ -1144,7 +1183,6 @@ 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) {
@@ -1179,7 +1217,6 @@ static void writefd(int fd,char *buf,size_t len)
 	}
 }
 
-
 void write_shortint(int f, int x)
 {
 	uchar b[2];
@@ -1188,7 +1225,6 @@ void write_shortint(int f, int x)
 	writefd(f, (char *)b, 2);
 }
 
-
 void write_int(int f,int32 x)
 {
 	char b[4];
@@ -1196,7 +1232,6 @@ 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;
@@ -1204,7 +1239,6 @@ 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.
@@ -1266,7 +1300,6 @@ void write_vstring(int f, char *str, int len)
 		writefd(f, str, len);
 }
 
-
 /**
  * Read a line of up to @p maxlen characters into @p buf (not counting
  * the trailing null).  Strips the (required) trailing newline and all
@@ -1292,11 +1325,10 @@ 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);
@@ -1306,10 +1338,14 @@ 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)
 {