1 files changed, 124 insertions, 0 deletions
diff --git a/sys-apps/busybox/files/ginit.c b/sys-apps/busybox/files/ginit.c
new file mode 100644
index 0000000..355ae48
--- /dev/null
+++ b/sys-apps/busybox/files/ginit.c
@@ -0,0 +1,124 @@
+/*
+ * simple init to bootstrap sep-/usr
+ *
+ * Copyright (C) 2012 Mike Frysinger <vapier@gentoo.org>
+ *
+ * Licensed under GPLv2 or later
+ */
+
+//applet:IF_INIT(APPLET(ginit, BB_DIR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_GINIT) += ginit.o
+
+//config:config GINIT
+//config:	bool "ginit"
+//config:	default y
+//config:	select MKDIR
+//config:	select MDEV
+//config:	select MOUNT
+//config:	select MOUNTPOINT
+//config:	help
+//config:	  sep-/usr bootstrapper
+
+//usage:#define ginit_trivial_usage NOUSAGE_STR
+//usage:#define ginit_full_usage ""
+
+#include "libbb.h"
+
+#define eprintf(fmt, args...) printf("%s" fmt, "sep-usr init: ", ## args)
+
+static void process_args(char **args)
+{
+	size_t i;
+
+	eprintf("running: ");
+	for (i = 0; args[i]; ++i) {
+		/* String needs to be writable, so dupe it */
+		args[i] = xstrdup(args[i]);
+		printf("'%s' ", args[i]);
+	}
+	printf("\n");
+}
+
+int ginit_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ginit_main(int argc UNUSED_PARAM, char **argv)
+{
+	FILE *mntlist;
+	bool ismnted_dev, ismnted_sys, ismnted_usr;
+	struct mntent *mntent;
+
+	/*
+	int fd = open("/dev/console", O_RDWR);
+	if (fd >= 0) {
+		dup2(fd, 0);
+		dup2(fd, 1);
+		dup2(fd, 2);
+	}
+	*/
+
+	/* If given an argv[] with an applet name, run it instead.
+	 * Makes recovering simple by doing: init=/ginit bb
+	 */
+	if (argv[1] && argv[1][0] != '/') {
+		eprintf("running user requested applet %s\n", argv[1]);
+		return spawn_and_wait(argv+1);
+	}
+
+#define saw(argv...) \
+	({ \
+		static const char *args[] = { argv, NULL }; \
+		/* These casts are fine -- see process_args for mem setup */ \
+		process_args((void *)args); \
+		spawn_and_wait((void *)args); \
+	})
+
+	/* First setup basic /dev */
+	if (saw("mountpoint", "-q", "/dev") != 0) {
+		/* Try /etc/fstab */
+		if (saw("mount", "-n", "/dev"))
+			/* Then devtmpfs */
+			if (saw("mount", "-n", "-t", "devtmpfs", "devtmpfs", "/dev"))
+				/* Finally normal tmpfs */
+				saw("mount", "-n", "-t", "tmpfs", "dev", "/dev");
+	} else {
+		eprintf("%s appears to be mounted; skipping its setup\n", "/dev");
+	}
+
+	/* If /dev is empty (e.g. tmpfs), run mdev to seed things */
+	if (access("/dev/console", F_OK) != 0) {
+		if (saw("mountpoint", "-q", "/sys") != 0) {
+			if (saw("mount", "-n", "/sys"))
+				saw("mount", "-n", "-t", "sysfs", "sysfs", "/sys");
+		} else {
+			eprintf("%s appears to be mounted; skipping its setup\n", "/sys");
+		}
+
+		/* Mount /proc as mdev will fork+exec /proc/self/exe */
+		if (saw("mountpoint", "-q", "/proc") != 0) {
+			/* Try /etc/fstab */
+			if (saw("mount", "-n", "/proc"))
+				saw("mount", "-n", "-t", "proc", "proc", "/proc");
+		}
+
+		saw("mdev", "-s");
+	}
+
+	/* Then seed the stuff we care about */
+	saw("mkdir", "-p", "/dev/pts", "/dev/shm");
+
+	/* Then mount /usr */
+	if (saw("mountpoint", "-q", "/usr") != 0) {
+		saw("mount", "-n", "/usr", "-o", "ro");
+	} else {
+		eprintf("%s appears to be mounted; skipping its setup\n", "/usr");
+	}
+
+	/* Now that we're all done, exec the real init */
+	if (!argv[1]) {
+		argv[0] = (void *)"/sbin/init";
+		argv[1] = NULL;
+	} else
+		++argv;
+	process_args(argv);
+	return execv(argv[0], argv);
+}