Add output truncation flag

This commit adds a "truncate" flag that can be added to a service
description between the "tty" keyword and the path string.

If the flag is set, the output file is truncated to 0 after opening.

This probably requires some remodeling in the future as the tty keyword
no longer deals with just tty devices.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>

1 files changed, 8 insertions, 5 deletions

diff --git a/cmd/runsvc/runsvc.c b/cmd/runsvc/runsvc.c
index a8e5bb2..9e646e7 100644
--- a/cmd/runsvc/runsvc.c
+++ b/cmd/runsvc/runsvc.c
@@ -17,17 +17,20 @@
  */
 #include "runsvc.h"
 
-static int setup_tty(const char *ctty)
+static int setup_tty(service_t *svc)
 {
 	int fd;
 
-	if (ctty != NULL) {
-		fd = open(ctty, O_RDWR);
+	if (svc->ctty != NULL) {
+		fd = open(svc->ctty, O_RDWR);
 		if (fd < 0) {
-			perror(ctty);
+			perror(svc->ctty);
 			return -1;
 		}
 
+		if (svc->flags & SVC_FLAG_TRUNCATE_OUT)
+			ftruncate(fd, 0);
+
 		close(STDIN_FILENO);
 		close(STDOUT_FILENO);
 		close(STDERR_FILENO);
@@ -125,7 +128,7 @@ int main(int argc, char **argv)
 	if (initenv())
 		goto out;
 
-	if (setup_tty(svc->ctty))
+	if (setup_tty(svc))
 		goto out;
 
 	if (svc->exec->next == NULL)