From: Karel Zak <kzak@redhat.com>
Date: Wed, 8 Nov 2017 10:38:26 +0000 (+0100)
Subject: setsid: new option --fork
X-Git-Tag: v2.32-rc1~222
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=180176213000b15cabc7bf39f7cad656b8f5ae38;p=thirdparty%2Futil-linux.git

setsid: new option --fork

Let's make semantic more predictable.

Addresses: https://github.com/karelzak/util-linux/issues/518
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/sys-utils/setsid.1 b/sys-utils/setsid.1
index 61b13ce1db..64f0555716 100644
--- a/sys-utils/setsid.1
+++ b/sys-utils/setsid.1
@@ -12,13 +12,17 @@ setsid \- run a program in a new session
 .B setsid
 runs a program in a new session. The command calls
 .BR fork (2)
-if already a process group leader. Otherwise, it executes a program in the
-current process.
+if already a process group leader.  Otherwise, it executes a program in the
+current process.  This default behavior is possible to override by
+the \fB\-\-fork\fR option.
 .SH OPTIONS
 .TP
 .BR \-c , " \-\-ctty"
 Set the controlling terminal to the current one.
 .TP
+.BR \-f , " \-\-fork"
+Always create a new process.
+.TP
 .BR \-w , " \-\-wait"
 Wait for the execution of the program to end, and return the exit value of
 this program as the return value of
diff --git a/sys-utils/setsid.c b/sys-utils/setsid.c
index 0b13952322..2991da0583 100644
--- a/sys-utils/setsid.c
+++ b/sys-utils/setsid.c
@@ -38,6 +38,7 @@ static void __attribute__((__noreturn__)) usage(void)
 
 	fputs(USAGE_OPTIONS, out);
 	fputs(_(" -c, --ctty     set the controlling terminal to the current one\n"), out);
+	fputs(_(" -f, --fork     always fork\n"), out);
 	fputs(_(" -w, --wait     wait program to exit, and use the same return\n"), out);
 
 	printf(USAGE_HELP_OPTIONS(16));
@@ -48,13 +49,14 @@ static void __attribute__((__noreturn__)) usage(void)
 
 int main(int argc, char **argv)
 {
-	int ch;
+	int ch, forcefork = 0;
 	int ctty = 0;
 	pid_t pid;
 	int status = 0;
 
 	static const struct option longopts[] = {
 		{"ctty", no_argument, NULL, 'c'},
+		{"fork", no_argument, NULL, 'f'},
 		{"wait", no_argument, NULL, 'w'},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, 'h'},
@@ -66,7 +68,7 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((ch = getopt_long(argc, argv, "+Vhcw", longopts, NULL)) != -1)
+	while ((ch = getopt_long(argc, argv, "+Vhcfw", longopts, NULL)) != -1)
 		switch (ch) {
 		case 'V':
 			printf(UTIL_LINUX_VERSION);
@@ -74,6 +76,9 @@ int main(int argc, char **argv)
 		case 'c':
 			ctty=1;
 			break;
+		case 'f':
+			forcefork = 1;
+			break;
 		case 'w':
 			status = 1;
 			break;
@@ -88,7 +93,7 @@ int main(int argc, char **argv)
 		errtryhelp(EXIT_FAILURE);
 	}
 
-	if (getpgrp() == getpid()) {
+	if (forcefork || getpgrp() == getpid()) {
 		pid = fork();
 		switch (pid) {
 		case -1: