From: nicm <nicm@openbsd.org>
Date: Thu, 11 Feb 2021 08:28:45 +0000 (+0000)
Subject: Move file handling protocol stuff all into file.c so it can be reused
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=0c0c2584134dbfad42dbd43ce22a56b1e92057f6;p=openbsd

Move file handling protocol stuff all into file.c so it can be reused
more easily.
---

diff --git a/usr.bin/tmux/client.c b/usr.bin/tmux/client.c
index defce19af20..9ef017eed77 100644
--- a/usr.bin/tmux/client.c
+++ b/usr.bin/tmux/client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: client.c,v 1.151 2021/01/17 16:17:41 nicm Exp $ */
+/* $OpenBSD: client.c,v 1.152 2021/02/11 08:28:45 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -477,257 +477,6 @@ client_send_identify(const char *ttynam, const char *cwd, int feat)
 	proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0);
 }
 
-/* File write error callback. */
-static void
-client_write_error_callback(__unused struct bufferevent *bev,
-    __unused short what, void *arg)
-{
-	struct client_file	*cf = arg;
-
-	log_debug("write error file %d", cf->stream);
-
-	bufferevent_free(cf->event);
-	cf->event = NULL;
-
-	close(cf->fd);
-	cf->fd = -1;
-
-	if (client_exitflag)
-		client_exit();
-}
-
-/* File write callback. */
-static void
-client_write_callback(__unused struct bufferevent *bev, void *arg)
-{
-	struct client_file	*cf = arg;
-
-	if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) {
-		bufferevent_free(cf->event);
-		close(cf->fd);
-		RB_REMOVE(client_files, &client_files, cf);
-		file_free(cf);
-	}
-
-	if (client_exitflag)
-		client_exit();
-}
-
-/* Open write file. */
-static void
-client_write_open(void *data, size_t datalen)
-{
-	struct msg_write_open	*msg = data;
-	const char		*path;
-	struct msg_write_ready	 reply;
-	struct client_file	 find, *cf;
-	const int		 flags = O_NONBLOCK|O_WRONLY|O_CREAT;
-	int			 error = 0;
-
-	if (datalen < sizeof *msg)
-		fatalx("bad MSG_WRITE_OPEN size");
-	if (datalen == sizeof *msg)
-		path = "-";
-	else
-		path = (const char *)(msg + 1);
-	log_debug("open write file %d %s", msg->stream, path);
-
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) {
-		cf = file_create(NULL, msg->stream, NULL, NULL);
-		RB_INSERT(client_files, &client_files, cf);
-	} else {
-		error = EBADF;
-		goto reply;
-	}
-	if (cf->closed) {
-		error = EBADF;
-		goto reply;
-	}
-
-	cf->fd = -1;
-	if (msg->fd == -1)
-		cf->fd = open(path, msg->flags|flags, 0644);
-	else {
-		if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO)
-			errno = EBADF;
-		else {
-			cf->fd = dup(msg->fd);
-			if (~client_flags & CLIENT_CONTROL)
-				close(msg->fd); /* can only be used once */
-		}
-	}
-	if (cf->fd == -1) {
-		error = errno;
-		goto reply;
-	}
-
-	cf->event = bufferevent_new(cf->fd, NULL, client_write_callback,
-	    client_write_error_callback, cf);
-	bufferevent_enable(cf->event, EV_WRITE);
-	goto reply;
-
-reply:
-	reply.stream = msg->stream;
-	reply.error = error;
-	proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply);
-}
-
-/* Write to client file. */
-static void
-client_write_data(void *data, size_t datalen)
-{
-	struct msg_write_data	*msg = data;
-	struct client_file	 find, *cf;
-	size_t			 size = datalen - sizeof *msg;
-
-	if (datalen < sizeof *msg)
-		fatalx("bad MSG_WRITE size");
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL)
-		fatalx("unknown stream number");
-	log_debug("write %zu to file %d", size, cf->stream);
-
-	if (cf->event != NULL)
-		bufferevent_write(cf->event, msg + 1, size);
-}
-
-/* Close client file. */
-static void
-client_write_close(void *data, size_t datalen)
-{
-	struct msg_write_close	*msg = data;
-	struct client_file	 find, *cf;
-
-	if (datalen != sizeof *msg)
-		fatalx("bad MSG_WRITE_CLOSE size");
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL)
-		fatalx("unknown stream number");
-	log_debug("close file %d", cf->stream);
-
-	if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) {
-		if (cf->event != NULL)
-			bufferevent_free(cf->event);
-		if (cf->fd != -1)
-			close(cf->fd);
-		RB_REMOVE(client_files, &client_files, cf);
-		file_free(cf);
-	}
-}
-
-/* File read callback. */
-static void
-client_read_callback(__unused struct bufferevent *bev, void *arg)
-{
-	struct client_file	*cf = arg;
-	void			*bdata;
-	size_t			 bsize;
-	struct msg_read_data	*msg;
-	size_t			 msglen;
-
-	msg = xmalloc(sizeof *msg);
-	for (;;) {
-		bdata = EVBUFFER_DATA(cf->event->input);
-		bsize = EVBUFFER_LENGTH(cf->event->input);
-
-		if (bsize == 0)
-			break;
-		if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg)
-			bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg;
-		log_debug("read %zu from file %d", bsize, cf->stream);
-
-		msglen = (sizeof *msg) + bsize;
-		msg = xrealloc(msg, msglen);
-		msg->stream = cf->stream;
-		memcpy(msg + 1, bdata, bsize);
-		proc_send(client_peer, MSG_READ, -1, msg, msglen);
-
-		evbuffer_drain(cf->event->input, bsize);
-	}
-	free(msg);
-}
-
-/* File read error callback. */
-static void
-client_read_error_callback(__unused struct bufferevent *bev,
-    __unused short what, void *arg)
-{
-	struct client_file	*cf = arg;
-	struct msg_read_done	 msg;
-
-	log_debug("read error file %d", cf->stream);
-
-	msg.stream = cf->stream;
-	msg.error = 0;
-	proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg);
-
-	bufferevent_free(cf->event);
-	close(cf->fd);
-	RB_REMOVE(client_files, &client_files, cf);
-	file_free(cf);
-}
-
-/* Open read file. */
-static void
-client_read_open(void *data, size_t datalen)
-{
-	struct msg_read_open	*msg = data;
-	const char		*path;
-	struct msg_read_done	 reply;
-	struct client_file	 find, *cf;
-	const int		 flags = O_NONBLOCK|O_RDONLY;
-	int			 error;
-
-	if (datalen < sizeof *msg)
-		fatalx("bad MSG_READ_OPEN size");
-	if (datalen == sizeof *msg)
-		path = "-";
-	else
-		path = (const char *)(msg + 1);
-	log_debug("open read file %d %s", msg->stream, path);
-
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) {
-		cf = file_create(NULL, msg->stream, NULL, NULL);
-		RB_INSERT(client_files, &client_files, cf);
-	} else {
-		error = EBADF;
-		goto reply;
-	}
-	if (cf->closed) {
-		error = EBADF;
-		goto reply;
-	}
-
-	cf->fd = -1;
-	if (msg->fd == -1)
-		cf->fd = open(path, flags);
-	else {
-		if (msg->fd != STDIN_FILENO)
-			errno = EBADF;
-		else {
-			cf->fd = dup(msg->fd);
-			if (~client_flags & CLIENT_CONTROL)
-				close(msg->fd); /* can only be used once */
-		}
-	}
-	if (cf->fd == -1) {
-		error = errno;
-		goto reply;
-	}
-
-	cf->event = bufferevent_new(cf->fd, client_read_callback, NULL,
-	    client_read_error_callback, cf);
-	bufferevent_enable(cf->event, EV_READ);
-	return;
-
-reply:
-	reply.stream = msg->stream;
-	reply.error = error;
-	proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply);
-}
-
 /* Run command in shell; used for -c. */
 static __dead void
 client_exec(const char *shell, const char *shellcmd)
@@ -802,6 +551,16 @@ client_signal(int sig)
 	}
 }
 
+/* Callback for file write error or close. */
+static void
+client_file_check_cb(__unused struct client *c, __unused const char *path,
+    __unused int error, __unused int closed, __unused struct evbuffer *buffer,
+    __unused void *data)
+{
+	if (client_exitflag)
+		client_exit();
+}
+
 /* Callback for client read events. */
 static void
 client_dispatch(struct imsg *imsg, __unused void *arg)
@@ -916,16 +675,20 @@ client_dispatch_wait(struct imsg *imsg)
 		proc_exit(client_proc);
 		break;
 	case MSG_READ_OPEN:
-		client_read_open(data, datalen);
+		file_read_open(&client_files, client_peer, imsg, 1,
+		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
+		    NULL);
 		break;
 	case MSG_WRITE_OPEN:
-		client_write_open(data, datalen);
+		file_write_open(&client_files, client_peer, imsg, 1,
+		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
+		    NULL);
 		break;
 	case MSG_WRITE:
-		client_write_data(data, datalen);
+		file_write_data(&client_files, imsg);
 		break;
 	case MSG_WRITE_CLOSE:
-		client_write_close(data, datalen);
+		file_write_close(&client_files, imsg);
 		break;
 	case MSG_OLDSTDERR:
 	case MSG_OLDSTDIN:
diff --git a/usr.bin/tmux/file.c b/usr.bin/tmux/file.c
index 9dd877d1430..0520b972de4 100644
--- a/usr.bin/tmux/file.c
+++ b/usr.bin/tmux/file.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: file.c,v 1.7 2020/05/26 08:41:47 nicm Exp $ */
+/* $OpenBSD: file.c,v 1.8 2021/02/11 08:28:45 nicm Exp $ */
 
 /*
  * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -30,10 +30,17 @@
 
 #include "tmux.h"
 
+/*
+ * IPC file handling. Both client and server use the same data structures
+ * (client_file and client_files) to store list of active files. Most functions
+ * are for use either in client or server but not both.
+ */
+
 static int	file_next_stream = 3;
 
 RB_GENERATE(client_files, client_file, entry, file_cmp);
 
+/* Get path for file, either as given or from working directory. */
 static char *
 file_get_path(struct client *c, const char *file)
 {
@@ -46,6 +53,7 @@ file_get_path(struct client *c, const char *file)
 	return (path);
 }
 
+/* Tree comparison function. */
 int
 file_cmp(struct client_file *cf1, struct client_file *cf2)
 {
@@ -56,11 +64,47 @@ file_cmp(struct client_file *cf1, struct client_file *cf2)
 	return (0);
 }
 
+/*
+ * Create a file object in the client process - the peer is the server to send
+ * messages to. Check callback is fired when the file is finished with so the
+ * process can decide if it needs to exit (if it is waiting for files to
+ * flush).
+ */
 struct client_file *
-file_create(struct client *c, int stream, client_file_cb cb, void *cbdata)
+file_create_with_peer(struct tmuxpeer *peer, struct client_files *files,
+    int stream, client_file_cb cb, void *cbdata)
 {
 	struct client_file	*cf;
 
+	cf = xcalloc(1, sizeof *cf);
+	cf->c = NULL;
+	cf->references = 1;
+	cf->stream = stream;
+
+	cf->buffer = evbuffer_new();
+	if (cf->buffer == NULL)
+		fatalx("out of memory");
+
+	cf->cb = cb;
+	cf->data = cbdata;
+
+	cf->peer = peer;
+	cf->tree = files;
+	RB_INSERT(client_files, files, cf);
+
+	return (cf);
+}
+
+/* Create a file object in the server, communicating with the given client. */
+struct client_file *
+file_create_with_client(struct client *c, int stream, client_file_cb cb,
+    void *cbdata)
+{
+	struct client_file	*cf;
+
+	if (c != NULL && (c->flags & CLIENT_ATTACHED))
+		c = NULL;
+
 	cf = xcalloc(1, sizeof *cf);
 	cf->c = c;
 	cf->references = 1;
@@ -74,6 +118,8 @@ file_create(struct client *c, int stream, client_file_cb cb, void *cbdata)
 	cf->data = cbdata;
 
 	if (cf->c != NULL) {
+		cf->peer = cf->c->peer;
+		cf->tree = &cf->c->files;
 		RB_INSERT(client_files, &cf->c->files, cf);
 		cf->c->references++;
 	}
@@ -81,6 +127,7 @@ file_create(struct client *c, int stream, client_file_cb cb, void *cbdata)
 	return (cf);
 }
 
+/* Free a file. */
 void
 file_free(struct client_file *cf)
 {
@@ -90,13 +137,15 @@ file_free(struct client_file *cf)
 	evbuffer_free(cf->buffer);
 	free(cf->path);
 
-	if (cf->c != NULL) {
-		RB_REMOVE(client_files, &cf->c->files, cf);
+	if (cf->tree != NULL)
+		RB_REMOVE(client_files, cf->tree, cf);
+	if (cf->c != NULL)
 		server_client_unref(cf->c);
-	}
+
 	free(cf);
 }
 
+/* Event to fire the done callback. */
 static void
 file_fire_done_cb(__unused int fd, __unused short events, void *arg)
 {
@@ -108,21 +157,22 @@ file_fire_done_cb(__unused int fd, __unused short events, void *arg)
 	file_free(cf);
 }
 
+/* Add an event to fire the done callback (used by the server). */
 void
 file_fire_done(struct client_file *cf)
 {
 	event_once(-1, EV_TIMEOUT, file_fire_done_cb, cf, NULL);
 }
 
+/* Fire the read callback. */
 void
 file_fire_read(struct client_file *cf)
 {
-	struct client	*c = cf->c;
-
 	if (cf->cb != NULL)
-		cf->cb(c, cf->path, cf->error, 0, cf->buffer, cf->data);
+		cf->cb(cf->c, cf->path, cf->error, 0, cf->buffer, cf->data);
 }
 
+/* Can this file be printed to? */
 int
 file_can_print(struct client *c)
 {
@@ -133,6 +183,7 @@ file_can_print(struct client *c)
 	return (1);
 }
 
+/* Print a message to a file. */
 void
 file_print(struct client *c, const char *fmt, ...)
 {
@@ -143,6 +194,7 @@ file_print(struct client *c, const char *fmt, ...)
 	va_end(ap);
 }
 
+/* Print a message to a file. */
 void
 file_vprint(struct client *c, const char *fmt, va_list ap)
 {
@@ -154,7 +206,7 @@ file_vprint(struct client *c, const char *fmt, va_list ap)
 
 	find.stream = 1;
 	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL) {
-		cf = file_create(c, 1, NULL, NULL);
+		cf = file_create_with_client(c, 1, NULL, NULL);
 		cf->path = xstrdup("-");
 
 		evbuffer_add_vprintf(cf->buffer, fmt, ap);
@@ -169,6 +221,7 @@ file_vprint(struct client *c, const char *fmt, va_list ap)
 	}
 }
 
+/* Print a buffer to a file. */
 void
 file_print_buffer(struct client *c, void *data, size_t size)
 {
@@ -180,7 +233,7 @@ file_print_buffer(struct client *c, void *data, size_t size)
 
 	find.stream = 1;
 	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL) {
-		cf = file_create(c, 1, NULL, NULL);
+		cf = file_create_with_client(c, 1, NULL, NULL);
 		cf->path = xstrdup("-");
 
 		evbuffer_add(cf->buffer, data, size);
@@ -195,6 +248,7 @@ file_print_buffer(struct client *c, void *data, size_t size)
 	}
 }
 
+/* Report an error to a file. */
 void
 file_error(struct client *c, const char *fmt, ...)
 {
@@ -209,7 +263,7 @@ file_error(struct client *c, const char *fmt, ...)
 
 	find.stream = 2;
 	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL) {
-		cf = file_create(c, 2, NULL, NULL);
+		cf = file_create_with_client(c, 2, NULL, NULL);
 		cf->path = xstrdup("-");
 
 		evbuffer_add_vprintf(cf->buffer, fmt, ap);
@@ -226,19 +280,21 @@ file_error(struct client *c, const char *fmt, ...)
 	va_end(ap);
 }
 
+/* Write data to a file. */
 void
 file_write(struct client *c, const char *path, int flags, const void *bdata,
     size_t bsize, client_file_cb cb, void *cbdata)
 {
 	struct client_file	*cf;
-	FILE			*f;
 	struct msg_write_open	*msg;
 	size_t			 msglen;
 	int			 fd = -1;
+	u_int			 stream = file_next_stream++;
+	FILE			*f;
 	const char		*mode;
 
 	if (strcmp(path, "-") == 0) {
-		cf = file_create(c, file_next_stream++, cb, cbdata);
+		cf = file_create_with_client(c, stream, cb, cbdata);
 		cf->path = xstrdup("-");
 
 		fd = STDOUT_FILENO;
@@ -251,7 +307,7 @@ file_write(struct client *c, const char *path, int flags, const void *bdata,
 		goto skip;
 	}
 
-	cf = file_create(c, file_next_stream++, cb, cbdata);
+	cf = file_create_with_client(c, stream, cb, cbdata);
 	cf->path = file_get_path(c, path);
 
 	if (c == NULL || c->flags & CLIENT_ATTACHED) {
@@ -286,7 +342,7 @@ skip:
 	msg->fd = fd;
 	msg->flags = flags;
 	memcpy(msg + 1, cf->path, msglen - sizeof *msg);
-	if (proc_send(c->peer, MSG_WRITE_OPEN, -1, msg, msglen) != 0) {
+	if (proc_send(cf->peer, MSG_WRITE_OPEN, -1, msg, msglen) != 0) {
 		free(msg);
 		cf->error = EINVAL;
 		goto done;
@@ -298,18 +354,21 @@ done:
 	file_fire_done(cf);
 }
 
+/* Read a file. */
 void
 file_read(struct client *c, const char *path, client_file_cb cb, void *cbdata)
 {
 	struct client_file	*cf;
-	FILE			*f;
 	struct msg_read_open	*msg;
-	size_t			 msglen, size;
+	size_t			 msglen;
 	int			 fd = -1;
+	u_int			 stream = file_next_stream++;
+	FILE			*f;
+	size_t			 size;
 	char			 buffer[BUFSIZ];
 
 	if (strcmp(path, "-") == 0) {
-		cf = file_create(c, file_next_stream++, cb, cbdata);
+		cf = file_create_with_client(c, stream, cb, cbdata);
 		cf->path = xstrdup("-");
 
 		fd = STDIN_FILENO;
@@ -322,7 +381,7 @@ file_read(struct client *c, const char *path, client_file_cb cb, void *cbdata)
 		goto skip;
 	}
 
-	cf = file_create(c, file_next_stream++, cb, cbdata);
+	cf = file_create_with_client(c, stream, cb, cbdata);
 	cf->path = file_get_path(c, path);
 
 	if (c == NULL || c->flags & CLIENT_ATTACHED) {
@@ -358,7 +417,7 @@ skip:
 	msg->stream = cf->stream;
 	msg->fd = fd;
 	memcpy(msg + 1, cf->path, msglen - sizeof *msg);
-	if (proc_send(c->peer, MSG_READ_OPEN, -1, msg, msglen) != 0) {
+	if (proc_send(cf->peer, MSG_READ_OPEN, -1, msg, msglen) != 0) {
 		free(msg);
 		cf->error = EINVAL;
 		goto done;
@@ -370,21 +429,21 @@ done:
 	file_fire_done(cf);
 }
 
+/* Push event, fired if there is more writing to be done. */
 static void
 file_push_cb(__unused int fd, __unused short events, void *arg)
 {
 	struct client_file	*cf = arg;
-	struct client		*c = cf->c;
 
-	if (~c->flags & CLIENT_DEAD)
+	if (cf->c == NULL || ~cf->c->flags & CLIENT_DEAD)
 		file_push(cf);
 	file_free(cf);
 }
 
+/* Push uwritten data to the client for a file, if it will accept it. */
 void
 file_push(struct client_file *cf)
 {
-	struct client		*c = cf->c;
 	struct msg_write_data	*msg;
 	size_t			 msglen, sent, left;
 	struct msg_write_close	 close;
@@ -400,21 +459,344 @@ file_push(struct client_file *cf)
 		msg = xrealloc(msg, msglen);
 		msg->stream = cf->stream;
 		memcpy(msg + 1, EVBUFFER_DATA(cf->buffer), sent);
-		if (proc_send(c->peer, MSG_WRITE, -1, msg, msglen) != 0)
+		if (proc_send(cf->peer, MSG_WRITE, -1, msg, msglen) != 0)
 			break;
 		evbuffer_drain(cf->buffer, sent);
 
 		left = EVBUFFER_LENGTH(cf->buffer);
-		log_debug("%s: file %d sent %zu, left %zu", c->name, cf->stream,
-		    sent, left);
+		log_debug("file %d sent %zu, left %zu", cf->stream, sent, left);
 	}
 	if (left != 0) {
 		cf->references++;
 		event_once(-1, EV_TIMEOUT, file_push_cb, cf, NULL);
 	} else if (cf->stream > 2) {
 		close.stream = cf->stream;
-		proc_send(c->peer, MSG_WRITE_CLOSE, -1, &close, sizeof close);
+		proc_send(cf->peer, MSG_WRITE_CLOSE, -1, &close, sizeof close);
 		file_fire_done(cf);
 	}
 	free(msg);
 }
+
+/* Client file write error callback. */
+static void
+file_write_error_callback(__unused struct bufferevent *bev, __unused short what,
+    void *arg)
+{
+	struct client_file	*cf = arg;
+
+	log_debug("write error file %d", cf->stream);
+
+	if (cf->cb != NULL)
+		cf->cb(NULL, NULL, 0, -1, NULL, cf->data);
+
+	bufferevent_free(cf->event);
+	cf->event = NULL;
+
+	close(cf->fd);
+	cf->fd = -1;
+}
+
+/* Client file write callback. */
+static void
+file_write_callback(__unused struct bufferevent *bev, void *arg)
+{
+	struct client_file	*cf = arg;
+
+	log_debug("write check file %d", cf->stream);
+
+	if (cf->cb != NULL)
+		cf->cb(NULL, NULL, 0, -1, NULL, cf->data);
+
+	if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) {
+		bufferevent_free(cf->event);
+		close(cf->fd);
+		RB_REMOVE(client_files, cf->tree, cf);
+		file_free(cf);
+	}
+}
+
+/* Handle a file write open message (client). */
+void
+file_write_open(struct client_files *files, struct tmuxpeer *peer,
+    struct imsg *imsg, int allow_streams, int close_received,
+    client_file_cb cb, void *cbdata)
+{
+	struct msg_write_open	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	const char		*path;
+	struct msg_write_ready	 reply;
+	struct client_file	 find, *cf;
+	const int		 flags = O_NONBLOCK|O_WRONLY|O_CREAT;
+	int			 error = 0;
+
+	if (msglen < sizeof *msg)
+		fatalx("bad MSG_WRITE_OPEN size");
+	if (msglen == sizeof *msg)
+		path = "-";
+	else
+		path = (const char *)(msg + 1);
+	log_debug("open write file %d %s", msg->stream, path);
+
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) != NULL) {
+		error = EBADF;
+		goto reply;
+	}
+	cf = file_create_with_peer(peer, files, msg->stream, cb, cbdata);
+	if (cf->closed) {
+		error = EBADF;
+		goto reply;
+	}
+
+	cf->fd = -1;
+	if (msg->fd == -1)
+		cf->fd = open(path, msg->flags|flags, 0644);
+	else if (allow_streams) {
+		if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO)
+			errno = EBADF;
+		else {
+			cf->fd = dup(msg->fd);
+			if (close_received)
+				close(msg->fd); /* can only be used once */
+		}
+	} else
+	      errno = EBADF;
+	if (cf->fd == -1) {
+		error = errno;
+		goto reply;
+	}
+
+	cf->event = bufferevent_new(cf->fd, NULL, file_write_callback,
+	    file_write_error_callback, cf);
+	bufferevent_enable(cf->event, EV_WRITE);
+	goto reply;
+
+reply:
+	reply.stream = msg->stream;
+	reply.error = error;
+	proc_send(peer, MSG_WRITE_READY, -1, &reply, sizeof reply);
+}
+
+/* Handle a file write data message (client). */
+void
+file_write_data(struct client_files *files, struct imsg *imsg)
+{
+	struct msg_write_data	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	struct client_file	 find, *cf;
+	size_t			 size = msglen - sizeof *msg;
+
+	if (msglen < sizeof *msg)
+		fatalx("bad MSG_WRITE size");
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) == NULL)
+		fatalx("unknown stream number");
+	log_debug("write %zu to file %d", size, cf->stream);
+
+	if (cf->event != NULL)
+		bufferevent_write(cf->event, msg + 1, size);
+}
+
+/* Handle a file write close message (client). */
+void
+file_write_close(struct client_files *files, struct imsg *imsg)
+{
+	struct msg_write_close	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	struct client_file	 find, *cf;
+
+	if (msglen != sizeof *msg)
+		fatalx("bad MSG_WRITE_CLOSE size");
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) == NULL)
+		fatalx("unknown stream number");
+	log_debug("close file %d", cf->stream);
+
+	if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) {
+		if (cf->event != NULL)
+			bufferevent_free(cf->event);
+		if (cf->fd != -1)
+			close(cf->fd);
+		RB_REMOVE(client_files, files, cf);
+		file_free(cf);
+	}
+}
+
+/* Client file read error callback. */
+static void
+file_read_error_callback(__unused struct bufferevent *bev, __unused short what,
+    void *arg)
+{
+	struct client_file	*cf = arg;
+	struct msg_read_done	 msg;
+
+	log_debug("read error file %d", cf->stream);
+
+	msg.stream = cf->stream;
+	msg.error = 0;
+	proc_send(cf->peer, MSG_READ_DONE, -1, &msg, sizeof msg);
+
+	bufferevent_free(cf->event);
+	close(cf->fd);
+	RB_REMOVE(client_files, cf->tree, cf);
+	file_free(cf);
+}
+
+/* Client file read callback. */
+static void
+file_read_callback(__unused struct bufferevent *bev, void *arg)
+{
+	struct client_file	*cf = arg;
+	void			*bdata;
+	size_t			 bsize;
+	struct msg_read_data	*msg;
+	size_t			 msglen;
+
+	msg = xmalloc(sizeof *msg);
+	for (;;) {
+		bdata = EVBUFFER_DATA(cf->event->input);
+		bsize = EVBUFFER_LENGTH(cf->event->input);
+
+		if (bsize == 0)
+			break;
+		if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg)
+			bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg;
+		log_debug("read %zu from file %d", bsize, cf->stream);
+
+		msglen = (sizeof *msg) + bsize;
+		msg = xrealloc(msg, msglen);
+		msg->stream = cf->stream;
+		memcpy(msg + 1, bdata, bsize);
+		proc_send(cf->peer, MSG_READ, -1, msg, msglen);
+
+		evbuffer_drain(cf->event->input, bsize);
+	}
+	free(msg);
+}
+
+/* Handle a file read open message (client). */
+void
+file_read_open(struct client_files *files, struct tmuxpeer *peer,
+    struct imsg *imsg, int allow_streams, int close_received, client_file_cb cb,
+    void *cbdata)
+{
+	struct msg_read_open	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	const char		*path;
+	struct msg_read_done	 reply;
+	struct client_file	 find, *cf;
+	const int		 flags = O_NONBLOCK|O_RDONLY;
+	int			 error;
+
+	if (msglen < sizeof *msg)
+		fatalx("bad MSG_READ_OPEN size");
+	if (msglen == sizeof *msg)
+		path = "-";
+	else
+		path = (const char *)(msg + 1);
+	log_debug("open read file %d %s", msg->stream, path);
+
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) != NULL) {
+		error = EBADF;
+		goto reply;
+	}
+	cf = file_create_with_peer(peer, files, msg->stream, cb, cbdata);
+	if (cf->closed) {
+		error = EBADF;
+		goto reply;
+	}
+
+	cf->fd = -1;
+	if (msg->fd == -1)
+		cf->fd = open(path, flags);
+	else if (allow_streams) {
+		if (msg->fd != STDIN_FILENO)
+			errno = EBADF;
+		else {
+			cf->fd = dup(msg->fd);
+			if (close_received)
+				close(msg->fd); /* can only be used once */
+		}
+	} else
+		errno = EBADF;
+	if (cf->fd == -1) {
+		error = errno;
+		goto reply;
+	}
+
+	cf->event = bufferevent_new(cf->fd, file_read_callback, NULL,
+	    file_read_error_callback, cf);
+	bufferevent_enable(cf->event, EV_READ);
+	return;
+
+reply:
+	reply.stream = msg->stream;
+	reply.error = error;
+	proc_send(peer, MSG_READ_DONE, -1, &reply, sizeof reply);
+}
+
+/* Handle a write ready message (server). */
+void
+file_write_ready(struct client_files *files, struct imsg *imsg)
+{
+	struct msg_write_ready	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	struct client_file	 find, *cf;
+
+	if (msglen != sizeof *msg)
+		fatalx("bad MSG_WRITE_READY size");
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) == NULL)
+		return;
+	if (msg->error != 0) {
+		cf->error = msg->error;
+		file_fire_done(cf);
+	} else
+		file_push(cf);
+}
+
+/* Handle read data message (server). */
+void
+file_read_data(struct client_files *files, struct imsg *imsg)
+{
+	struct msg_read_data	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	struct client_file	 find, *cf;
+	void			*bdata = msg + 1;
+	size_t			 bsize = msglen - sizeof *msg;
+
+	if (msglen < sizeof *msg)
+		fatalx("bad MSG_READ_DATA size");
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) == NULL)
+		return;
+
+	log_debug("file %d read %zu bytes", cf->stream, bsize);
+	if (cf->error == 0) {
+		if (evbuffer_add(cf->buffer, bdata, bsize) != 0) {
+			cf->error = ENOMEM;
+			file_fire_done(cf);
+		} else
+			file_fire_read(cf);
+	}
+}
+
+/* Handle a read done message (server). */
+void
+file_read_done(struct client_files *files, struct imsg *imsg)
+{
+	struct msg_read_done	*msg = imsg->data;
+	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	struct client_file	 find, *cf;
+
+	if (msglen != sizeof *msg)
+		fatalx("bad MSG_READ_DONE size");
+	find.stream = msg->stream;
+	if ((cf = RB_FIND(client_files, files, &find)) == NULL)
+		return;
+
+	log_debug("file %d read done", cf->stream);
+	cf->error = msg->error;
+	file_fire_done(cf);
+}
diff --git a/usr.bin/tmux/server-client.c b/usr.bin/tmux/server-client.c
index 9d5b3d6476c..0a1245ccc93 100644
--- a/usr.bin/tmux/server-client.c
+++ b/usr.bin/tmux/server-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: server-client.c,v 1.368 2021/02/08 08:33:54 nicm Exp $ */
+/* $OpenBSD: server-client.c,v 1.369 2021/02/11 08:28:45 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -51,12 +51,6 @@ static void	server_client_dispatch(struct imsg *, void *);
 static void	server_client_dispatch_command(struct client *, struct imsg *);
 static void	server_client_dispatch_identify(struct client *, struct imsg *);
 static void	server_client_dispatch_shell(struct client *);
-static void	server_client_dispatch_write_ready(struct client *,
-		    struct imsg *);
-static void	server_client_dispatch_read_data(struct client *,
-		    struct imsg *);
-static void	server_client_dispatch_read_done(struct client *,
-		    struct imsg *);
 
 /* Compare client windows. */
 static int
@@ -2070,13 +2064,13 @@ server_client_dispatch(struct imsg *imsg, void *arg)
 		server_client_dispatch_shell(c);
 		break;
 	case MSG_WRITE_READY:
-		server_client_dispatch_write_ready(c, imsg);
+		file_write_ready(&c->files, imsg);
 		break;
 	case MSG_READ:
-		server_client_dispatch_read_data(c, imsg);
+		file_read_data(&c->files, imsg);
 		break;
 	case MSG_READ_DONE:
-		server_client_dispatch_read_done(c, imsg);
+		file_read_done(&c->files, imsg);
 		break;
 	}
 }
@@ -2302,71 +2296,6 @@ server_client_dispatch_shell(struct client *c)
 	proc_kill_peer(c->peer);
 }
 
-/* Handle write ready message. */
-static void
-server_client_dispatch_write_ready(struct client *c, struct imsg *imsg)
-{
-	struct msg_write_ready	*msg = imsg->data;
-	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
-	struct client_file	 find, *cf;
-
-	if (msglen != sizeof *msg)
-		fatalx("bad MSG_WRITE_READY size");
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL)
-		return;
-	if (msg->error != 0) {
-		cf->error = msg->error;
-		file_fire_done(cf);
-	} else
-		file_push(cf);
-}
-
-/* Handle read data message. */
-static void
-server_client_dispatch_read_data(struct client *c, struct imsg *imsg)
-{
-	struct msg_read_data	*msg = imsg->data;
-	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
-	struct client_file	 find, *cf;
-	void			*bdata = msg + 1;
-	size_t			 bsize = msglen - sizeof *msg;
-
-	if (msglen < sizeof *msg)
-		fatalx("bad MSG_READ_DATA size");
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL)
-		return;
-
-	log_debug("%s: file %d read %zu bytes", c->name, cf->stream, bsize);
-	if (cf->error == 0) {
-		if (evbuffer_add(cf->buffer, bdata, bsize) != 0) {
-			cf->error = ENOMEM;
-			file_fire_done(cf);
-		} else
-			file_fire_read(cf);
-	}
-}
-
-/* Handle read done message. */
-static void
-server_client_dispatch_read_done(struct client *c, struct imsg *imsg)
-{
-	struct msg_read_done	*msg = imsg->data;
-	size_t			 msglen = imsg->hdr.len - IMSG_HEADER_SIZE;
-	struct client_file	 find, *cf;
-
-	if (msglen != sizeof *msg)
-		fatalx("bad MSG_READ_DONE size");
-	find.stream = msg->stream;
-	if ((cf = RB_FIND(client_files, &c->files, &find)) == NULL)
-		return;
-
-	log_debug("%s: file %d read done", c->name, cf->stream);
-	cf->error = msg->error;
-	file_fire_done(cf);
-}
-
 /* Get client working directory. */
 const char *
 server_client_get_cwd(struct client *c, struct session *s)
diff --git a/usr.bin/tmux/tmux.h b/usr.bin/tmux/tmux.h
index 3ad7d9d4f80..243ac4b9580 100644
--- a/usr.bin/tmux/tmux.h
+++ b/usr.bin/tmux/tmux.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1088 2021/02/05 12:29:19 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1089 2021/02/11 08:28:45 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1539,6 +1539,8 @@ typedef void (*client_file_cb) (struct client *, const char *, int, int,
     struct evbuffer *, void *);
 struct client_file {
 	struct client			*c;
+	struct tmuxpeer			*peer;
+	struct client_files		*tree;
 	int				 references;
 	int				 stream;
 
@@ -1907,6 +1909,7 @@ int	load_cfg(const char *, struct client *, struct cmdq_item *, int,
 int	load_cfg_from_buffer(const void *, size_t, const char *,
 	    struct client *, struct cmdq_item *, int, struct cmdq_item **);
 void	set_cfg_file(const char *);
+const char *get_cfg_file(void);
 void printflike(1, 2) cfg_add_cause(const char *, ...);
 void	cfg_print_causes(struct cmdq_item *);
 void	cfg_show_causes(struct session *);
@@ -2370,7 +2373,10 @@ void	alerts_check_session(struct session *);
 /* file.c */
 int	 file_cmp(struct client_file *, struct client_file *);
 RB_PROTOTYPE(client_files, client_file, entry, file_cmp);
-struct client_file *file_create(struct client *, int, client_file_cb, void *);
+struct client_file *file_create_with_peer(struct tmuxpeer *,
+	    struct client_files *, int, client_file_cb, void *);
+struct client_file *file_create_with_client(struct client *, int,
+	    client_file_cb, void *);
 void	 file_free(struct client_file *);
 void	 file_fire_done(struct client_file *);
 void	 file_fire_read(struct client_file *);
@@ -2383,6 +2389,15 @@ void	 file_write(struct client *, const char *, int, const void *, size_t,
 	     client_file_cb, void *);
 void	 file_read(struct client *, const char *, client_file_cb, void *);
 void	 file_push(struct client_file *);
+void	 file_write_open(struct client_files *, struct tmuxpeer *,
+	     struct imsg *, int, int, client_file_cb, void *);
+void	 file_write_data(struct client_files *, struct imsg *);
+void	 file_write_close(struct client_files *, struct imsg *);
+void	 file_read_open(struct client_files *, struct tmuxpeer *, struct imsg *,
+	     int, int, client_file_cb, void *);
+void	 file_write_ready(struct client_files *, struct imsg *);
+void	 file_read_data(struct client_files *, struct imsg *);
+void	 file_read_done(struct client_files *, struct imsg *);
 
 /* server.c */
 extern struct tmuxproc *server_proc;