cleanup: initd: simplify and merge linux specific code into main.c

Targetting anything else than Linux isn't really relevant. All
other systems ($BSD and other Unices) are a closed ecosystem
where kernel & userspace are developed together. They don't need
something like a third party init system, so compatibillity can
be largely ignored.

Signed-off-by: David Oberhollenzer <goliath@infraroot.at>

initd/Makemodule.am

@@ -1,4 +1,4 @@
-init_SOURCES = initd/main.c initd/init.h initd/signal_linux.c initd/runsvc.c
+init_SOURCES = initd/main.c initd/init.h initd/runsvc.c
 init_SOURCES += initd/status.c initd/supervisor.c initd/initsock.c
 init_CPPFLAGS = $(AM_CPPFLAGS)
 init_CFLAGS = $(AM_CFLAGS)

initd/init.h

@@ -77,29 +77,6 @@ void supervisor_start(int id);
 
 void supervisor_stop(int id);
 
-/********** signal_<platform>.c **********/
-
-/*
-	Setup signal handling. Returns -1 on error, a file descriptor on
-	success.
-
-	The returned file descriptor can be polled and becomes readable
-	when a signal arrives. Reading from it returns a signalfd_siginfo
-	structure.
-
-	The returned file descriptor has the close on exec flag set.
-
-	The kernel is also told to send us SIGINT signals if a user presses
-	the local equivalent of CTRL+ALT+DEL.
-*/
-int sigsetup(void);
-
-/*
-	Undo everything that sigsetup() changed about signal handling and
-	restore the default.
-*/
-void sigreset(void);
-
 /********** initsock.c **********/
 
 int init_socket_create(void);

initd/main.c

@@ -96,6 +96,29 @@ void target_completed(int target)
 	}
 }
 
+static int sigsetup(void)
+{
+	sigset_t mask;
+	int sfd;
+
+	sigfillset(&mask);
+	if (sigprocmask(SIG_SETMASK, &mask, NULL) == -1) {
+		perror("sigprocmask");
+		return -1;
+	}
+
+	sfd = signalfd(-1, &mask, SFD_CLOEXEC);
+	if (sfd == -1) {
+		perror("signalfd");
+		return -1;
+	}
+
+	if (reboot(LINUX_REBOOT_CMD_CAD_OFF))
+		perror("cannot disable CTRL+ALT+DEL");
+
+	return sfd;
+}
+
 int main(void)
 {
 	int i, ret, count;

initd/runsvc.c

@@ -10,6 +10,7 @@
 pid_t runsvc(service_t *svc)
 {
 	char *argv[4], *envp[1];
+	sigset_t mask;
 	pid_t pid;
 
 	argv[0] = (char *)RUNSVCBIN;
@@ -25,7 +26,9 @@ pid_t runsvc(service_t *svc)
 		perror("fork");
 
 	if (pid == 0) {
-		sigreset();
+		sigemptyset(&mask);
+		sigprocmask(SIG_SETMASK, &mask, NULL);
+
 		execve(argv[0], argv, envp);
 		perror(argv[0]);
 		exit(EXIT_FAILURE);

initd/signal_linux.c

@@ -1,42 +0,0 @@
-/* SPDX-License-Identifier: ISC */
-#include <stdio.h>
-
-#include "init.h"
-
-int sigsetup(void)
-{
-	sigset_t mask;
-	int sfd;
-
-	sigfillset(&mask);
-	if (sigprocmask(SIG_SETMASK, &mask, NULL) == -1) {
-		perror("sigprocmask");
-		return -1;
-	}
-
-	sigemptyset(&mask);
-	sigaddset(&mask, SIGCHLD);
-	sigaddset(&mask, SIGINT);
-	sigaddset(&mask, SIGTERM);
-	sigaddset(&mask, SIGUSR1);
-	sigaddset(&mask, SIGHUP);
-
-	sfd = signalfd(-1, &mask, SFD_CLOEXEC);
-	if (sfd == -1) {
-		perror("signalfd");
-		return -1;
-	}
-
-	if (reboot(LINUX_REBOOT_CMD_CAD_OFF))
-		perror("cannot disable CTRL+ALT+DEL");
-
-	return sfd;
-}
-
-void sigreset(void)
-{
-	sigset_t mask;
-
-	sigemptyset(&mask);
-	sigprocmask(SIG_SETMASK, &mask, NULL);
-}