Add sinit and remove busybox init

pkgs/busybox

@@ -9,9 +9,6 @@ install() {
 	pushd src/
 	chmod +x busybox
 	cp busybox $root/bin
-	pushd $root
-	ln -sf /bin/busybox init
-	popd
 	pushd $root/bin
 	ln -sf busybox addgroup
 	ln -sf busybox adduser
@@ -40,8 +37,6 @@ install() {
 	ln -sf busybox passwd
 	ln -sf busybox ping
 	ln -sf busybox pkill
-	ln -sf busybox poweroff
-	ln -sf busybox reboot
 	ln -sf busybox sed
 	ln -sf busybox sysctl
 	ln -sf busybox tac

pkgs/sinit

@@ -0,0 +1,13 @@
+fetch() {
+	cp $top/stuff/sinit.c src
+}
+
+build() {
+	pushd src
+	x86_64-linux-musl-gcc -o init sinit.c -static -I$libcroot/include/ncurses -lncurses || return 1
+	popd
+}
+
+install() {
+	cp src/init $root/
+}

stuff/sinit.c

@@ -0,0 +1,90 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+static int
+spawn(const char *file, char *const argv[])
+{
+	pid_t pid;
+
+	pid = fork();
+	if (pid < 0)
+		return pid;
+	if (pid == 0) {
+		setsid();
+		setpgid(0, 0);
+		execvp(file, argv);
+		_exit(errno == ENOENT ? 127 : 126);
+	}
+}
+
+int
+main(void)
+{
+	const char *fifopath = "/var/run/init.fifo";
+	sigset_t set;
+	pid_t pid;
+	fd_set rfds;
+	char buf[BUFSIZ], *p;
+	int c;
+	int fd;
+	int n;
+
+	if (getpid() != 1) return 1;
+
+	sigfillset(&set);
+	sigprocmask(SIG_BLOCK, &set, 0);
+
+	pid = fork();
+	if (pid < 0) return 1;
+	if (pid > 0) for (;;) wait(&c);
+
+	sigprocmask(SIG_UNBLOCK, &set, 0);
+
+	spawn("/bin/sh", (char *[]){ "sh", "-c", "/etc/rc", NULL });
+
+	unlink(fifopath);
+	umask(0);
+	mkfifo(fifopath, 0600);
+	fd = open(fifopath, O_RDWR | O_NONBLOCK);
+	while (1) {
+		FD_ZERO(&rfds);
+		FD_SET(fd, &rfds);
+		n = select(fd + 1, &rfds, NULL, NULL, NULL);
+		if (n <= 0)
+			continue;
+		if (FD_ISSET(fd, &rfds)) {
+			n = read(fd, buf, sizeof(buf) - 1);
+			if (n < 0 || n == 0)
+				continue;
+			buf[n] = '\0';
+			p = strchr(buf, '\n');
+			if (p) *p = '\0';
+			if (strcmp(buf, "reboot") == 0) {
+				spawn("/bin/sh", (char *[]){
+						"sh",
+						"-c",
+						"/etc/rc.shutdown reboot",
+						NULL
+				});
+			}
+			if (strcmp(buf, "poweroff") == 0) {
+				spawn("/bin/sh", (char *[]){
+						"sh",
+						"-c",
+						"/etc/rc.shutdown poweroff",
+						NULL
+				});
+			}
+		}
+	}
+
+	/* unreached */
+	return 0;
+}