fix sysvinit compatibility

This allows openrc to direct sysvinit to shut down the system by setting
the INIT_HALT environment variable appropriately. Also, we do not try to
communicate with sysvinit if its fifo does not exist.

src/rc/openrc-shutdown.c

@@ -330,16 +330,29 @@ int main(int argc, char **argv)
 	unlink(nologin_file);
 	unlink(shutdown_pid);
 	if (do_halt) {
+		if (exists("/run/initctl")) {
+			sysvinit_setenv("INIT_HALT", "HALT");
 			sysvinit_runlevel('0');
+		} else
 			send_cmd("halt");
 	} else if (do_kexec)
 		send_cmd("kexec");
-	else if (do_poweroff)
+	else if (do_poweroff) {
+		if (exists("/run/initctl")) {
+			sysvinit_setenv("INIT_HALT", "POWEROFF");
+			sysvinit_runlevel('0');
+		} else
 			send_cmd("poweroff");
-	else if (do_reboot) {
+	} else if (do_reboot) {
+		if (exists("/run/initctl"))
 			sysvinit_runlevel('6');
+		else
 			send_cmd("reboot");
-	} else if (do_single)
+	} else if (do_single) {
+		if (exists("/run/initctl"))
+			sysvinit_runlevel('S');
+		else
 			send_cmd("single");
+	}
 	return 0;
 }

src/rc/rc-sysvinit.c

@@ -26,31 +26,21 @@
 #include "einfo.h"
 #include "rc-sysvinit.h"
 
-void sysvinit_runlevel(char rl)
+static void sysvinit_send_cmd(struct init_request *request)
 {
-	struct init_request request;
 	int fd;
 	char *p;
 	size_t bytes;
 	ssize_t r;
 
-	if (!rl)
-		return;
-
 	fd = open("/run/initctl", O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
 	if (fd < 0) {
 		if (errno != ENOENT)
 			eerror("Failed to open initctl fifo: %s", strerror(errno));
 		return;
 	}
-	request = (struct init_request) {
-		.magic = INIT_MAGIC,
-		.sleeptime = 0,
-		.cmd = INIT_CMD_RUNLVL,
-		.runlevel = rl,
-	};
-	p = (char *) &request;
-	bytes = sizeof(request);
+	p = (char *) request;
+	bytes = sizeof(*request);
 	do {
 		r = write(fd, p, bytes);
 		if (r < 0) {
@@ -62,5 +52,51 @@ void sysvinit_runlevel(char rl)
 		p += r;
 		bytes -= r;
 	} while (bytes > 0);
-	exit(0);
+}
+
+void sysvinit_runlevel(char rl)
+{
+	struct init_request request;
+
+	if (!rl)
+		return;
+
+	request = (struct init_request) {
+		.magic = INIT_MAGIC,
+		.sleeptime = 0,
+		.cmd = INIT_CMD_RUNLVL,
+		.runlevel = rl,
+	};
+	sysvinit_send_cmd(&request);
+		return;
+}
+
+/*
+ *	Set environment variables in the init process.
+ */
+void sysvinit_setenv(char *name, char *value)
+{
+	struct init_request	request;
+	size_t nl;
+	size_t vl;
+
+	memset(&request, 0, sizeof(request));
+	request.magic = INIT_MAGIC;
+	request.cmd = INIT_CMD_SETENV;
+	nl = strlen(name);
+	if (value)
+		vl = strlen(value);
+else
+		vl = 0;
+
+	if (nl + vl + 3 >= (int)sizeof(request.i.data))
+		return -1;
+
+	memcpy(request.i.data, name, nl);
+	if (value) {
+		request.i.data[nl] = '=';
+		memcpy(request.i.data + nl + 1, value, vl);
+	}
+	sysvinit_send_cmd(&request);
+	return 0;
 }

src/rc/rc-sysvinit.h

@@ -67,5 +67,6 @@ struct init_request {
 };
 
 void sysvinit_runlevel(char rl);
+void sysvinit_setenv(char *name, char *value);
 
 #endif