Support attaching a client read-only with a new -r flag to the attach-session

command.

cmd-attach-session.c

@@ -28,8 +28,8 @@ int	cmd_attach_session_exec(struct cmd *, struct cmd_ctx *);
 
 const struct cmd_entry cmd_attach_session_entry = {
 	"attach-session", "attach",
-	"[-d] " CMD_TARGET_SESSION_USAGE,
-	CMD_CANTNEST|CMD_STARTSERVER|CMD_SENDENVIRON, "d",
+	"[-dr] " CMD_TARGET_SESSION_USAGE,
+	CMD_CANTNEST|CMD_STARTSERVER|CMD_SENDENVIRON, "dr",
 	cmd_target_init,
 	cmd_target_parse,
 	cmd_attach_session_exec,
@@ -89,6 +89,9 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			return (-1);
 		}
 
+		if (cmd_check_flag(data->chflags, 'r'))
+			ctx->cmdclient->flags |= CLIENT_READONLY;
+
 		if (cmd_check_flag(data->chflags, 'd'))
 			server_write_session(s, MSG_DETACH, NULL, 0);
 

cmd-detach-client.c

@@ -29,7 +29,7 @@ int	cmd_detach_client_exec(struct cmd *, struct cmd_ctx *);
 const struct cmd_entry cmd_detach_client_entry = {
 	"detach-client", "detach",
 	CMD_TARGET_CLIENT_USAGE,
-	0, "",
+	CMD_READONLY, "",
 	cmd_target_init,
 	cmd_target_parse,
 	cmd_detach_client_exec,

key-bindings.c

@@ -240,6 +240,8 @@ void
 key_bindings_dispatch(struct key_binding *bd, struct client *c)
 {
 	struct cmd_ctx	 ctx;
+	struct cmd	*cmd;
+	int		 readonly;
 
 	ctx.msgdata = NULL;
 	ctx.curclient = c;
@@ -250,5 +252,15 @@ key_bindings_dispatch(struct key_binding *bd, struct client *c)
 
 	ctx.cmdclient = NULL;
 
+	readonly = 1;
+	TAILQ_FOREACH(cmd, bd->cmdlist, qentry) {
+		if (!(cmd->entry->flags & CMD_READONLY))
+			readonly = 0;
+	}
+	if (!readonly && c->flags & CLIENT_READONLY) {
+		key_bindings_info(&ctx, "Client is read-only");
+		return;
+	}
+
 	cmd_list_exec(bd->cmdlist, &ctx);
 }

server-client.c

@@ -271,6 +271,8 @@ server_client_handle_key(int key, struct mouse_event *mouse, void *data)
 
 	/* Special case: number keys jump to pane in identify mode. */
 	if (c->flags & CLIENT_IDENTIFY && key >= '0' && key <= '9') {
+		if (c->flags & CLIENT_READONLY)
+			return;
 		wp = window_pane_at_index(w, key - '0');
 		if (wp != NULL && window_pane_visible(wp))
 			window_set_active_pane(w, wp);
@@ -279,15 +281,20 @@ server_client_handle_key(int key, struct mouse_event *mouse, void *data)
 	}
 
 	/* Handle status line. */
+	if (!(c->flags & CLIENT_READONLY)) {
 		status_message_clear(c);
 		server_clear_identify(c);
+	}
 	if (c->prompt_string != NULL) {
+		if (!(c->flags & CLIENT_READONLY))
 			status_prompt_key(c, key);
 		return;
 	}
 
 	/* Check for mouse keys. */
 	if (key == KEYC_MOUSE) {
+		if (c->flags & CLIENT_READONLY)
+			return;
 		if (options_get_number(oo, "mouse-select-pane")) {
 			window_set_active_at(w, mouse->x, mouse->y);
 			server_redraw_window_borders(w);
@@ -313,9 +320,10 @@ server_client_handle_key(int key, struct mouse_event *mouse, void *data)
 			c->flags |= CLIENT_PREFIX;
 		else {
 			/* Try as a non-prefix key binding. */
-			if ((bd = key_bindings_lookup(key)) == NULL)
+			if ((bd = key_bindings_lookup(key)) == NULL) {
+				if (!(c->flags & CLIENT_READONLY))
 					window_pane_key(wp, c, key);
-			else
+			} else
 				key_bindings_dispatch(bd, c);
 		}
 		return;
@@ -329,7 +337,7 @@ server_client_handle_key(int key, struct mouse_event *mouse, void *data)
 			c->flags &= ~CLIENT_REPEAT;
 			if (isprefix)
 				c->flags |= CLIENT_PREFIX;
-			else
+			else if (!(c->flags & CLIENT_READONLY))
 				window_pane_key(wp, c, key);
 		}
 		return;
@@ -340,7 +348,7 @@ server_client_handle_key(int key, struct mouse_event *mouse, void *data)
 		c->flags &= ~CLIENT_REPEAT;
 		if (isprefix)
 			c->flags |= CLIENT_PREFIX;
-		else
+		else if (!(c->flags & CLIENT_READONLY))
 			window_pane_key(wp, c, key);
 		return;
 	}
@@ -660,7 +668,6 @@ server_client_msg_command(struct client *c, struct msg_command_data *data)
 {
 	struct cmd_ctx	 ctx;
 	struct cmd_list	*cmdlist = NULL;
-	struct cmd	*cmd;
 	int		 argc;
 	char	       **argv, *cause;
 

tmux.1

@@ -364,7 +364,7 @@ new-window ; split-window -d
 The following commands are available:
 .Bl -tag -width Ds
 .It Xo Ic attach-session
-.Op Fl d
+.Op Fl dr
 .Op Fl t Ar target-session
 .Xc
 .D1 (alias: Ic attach )
@@ -376,6 +376,10 @@ If used from inside, switch the current client.
 If
 .Fl d
 is specified, any other clients attached to the session are detached.
+.Fl r
+signifies the client is read-only (only keys bound to the
+.Ic detach-client
+command have any effect)
 .Pp
 If no server is started,
 .Ic attach-session

tmux.h

@@ -1094,6 +1094,7 @@ struct client {
 #define CLIENT_IDENTIFY 0x100
 #define CLIENT_DEAD 0x200
 #define CLIENT_BORDERS 0x400
+#define CLIENT_READONLY 0x800
 	int		 flags;
 
 	struct event	 identify_timer;
@@ -1172,6 +1173,7 @@ struct cmd_entry {
 #define CMD_ARG01 0x10
 #define CMD_ARG2 0x20
 #define CMD_ARG12 0x40
+#define CMD_READONLY 0x80
 	int		 flags;
 
 	const char	*chflags;