Add a -D flag to ask tmux not to daemonize, useful both for running a debugger

(lldb does not have follow-fork-mode) and for running with a managed supervisor
init system. GitHub issue 2190.

1 files changed, 7 insertions, 2 deletions

diff --git a/tmux.c b/tmux.c
index 48b3b8b9..b600702c 100644
--- a/tmux.c
+++ b/tmux.c
@@ -54,7 +54,7 @@ static __dead void
 usage(void)
 {
 	fprintf(stderr,
-	    "usage: %s [-2CluvV] [-c shell-command] [-f file] [-L socket-name]\n"
+	    "usage: %s [-2CDluvV] [-c shell-command] [-f file] [-L socket-name]\n"
 	    "            [-S socket-path] [-T features] [command [flags]]\n",
 	    getprogname());
 	exit(1);
@@ -327,7 +327,7 @@ main(int argc, char **argv)
 	if (**argv == '-')
 		flags = CLIENT_LOGIN;
 
-	while ((opt = getopt(argc, argv, "2c:Cdf:lL:qS:T:uUvV")) != -1) {
+	while ((opt = getopt(argc, argv, "2c:CDdf:lL:qS:T:uUvV")) != -1) {
 		switch (opt) {
 		case '2':
 			tty_add_features(&feat, "256", ":,");
@@ -335,6 +335,9 @@ main(int argc, char **argv)
 		case 'c':
 			shell_command = optarg;
 			break;
+		case 'D':
+			flags |= CLIENT_NOFORK;
+			break;
 		case 'C':
 			if (flags & CLIENT_CONTROL)
 				flags |= CLIENT_CONTROLCONTROL;
@@ -378,6 +381,8 @@ main(int argc, char **argv)
 
 	if (shell_command != NULL && argc != 0)
 		usage();
+	if ((flags & CLIENT_NOFORK) && argc != 0)
+		usage();
 
 	if ((ptm_fd = getptmfd()) == -1)
 		err(1, "getptmfd");