1 files changed, 114 insertions, 0 deletions
diff --git a/usr/kinit/run-init/run-init.c b/usr/kinit/run-init/run-init.c
new file mode 100644
index 0000000..6a4ad3e
--- /dev/null
+++ b/usr/kinit/run-init/run-init.c
@@ -0,0 +1,114 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2004-2006 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Usage: exec run-init [-d caps] [-c /dev/console] [-n] [-p] /real-root /sbin/init "$@"
+ *
+ * This program should be called as the last thing in a shell script
+ * acting as /init in an initramfs; it does the following:
+ *
+ * 1. Delete all files in the initramfs;
+ * 2. Remounts /real-root onto the root filesystem;
+ * 3. Drops comma-separated list of capabilities;
+ * 4. Chroots;
+ * 5. Opens /dev/console;
+ * 6. Spawns the specified init program (with arguments.)
+ *
+ * With the -p option, it skips step 1 in order to allow the initramfs to
+ * be persisted into the running system.
+ *
+ * With the -n option, it skips steps 1, 2 and 6 and can be used to check
+ * whether the given root and init are likely to work.
+ */
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include "run-init.h"
+
+static const char *program;
+
+static void __attribute__ ((noreturn)) usage(void)
+{
+	fprintf(stderr,
+		"Usage: exec %s [-d caps] [-c consoledev] [-n] [-p] /real-root /sbin/init [args]\n",
+		program);
+	exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+	/* Command-line options and defaults */
+	const char *console = "/dev/console";
+	const char *realroot;
+	const char *init;
+	const char *error;
+	const char *drop_caps = NULL;
+	bool dry_run = false;
+	bool persist_initramfs = false;
+	char **initargs;
+
+	/* Variables... */
+	int o;
+
+	/* Parse the command line */
+	program = argv[0];
+
+	while ((o = getopt(argc, argv, "c:d:pn")) != -1) {
+		if (o == 'c') {
+			console = optarg;
+		} else if (o == 'd') {
+			drop_caps = optarg;
+		} else if (o == 'n') {
+			dry_run = true;
+		} else if (o == 'p') {
+			persist_initramfs = true;
+		} else {
+			usage();
+		}
+	}
+
+	if (argc - optind < 2)
+		usage();
+
+	realroot = argv[optind];
+	init = argv[optind + 1];
+	initargs = argv + optind + 1;
+
+	error = run_init(realroot, console, drop_caps, dry_run, persist_initramfs, init, initargs);
+
+	if (error) {
+		fprintf(stderr, "%s: %s: %s\n", program, error, strerror(errno));
+		return 1;
+	} else {
+		/* Must have been a dry run */
+		return 0;
+	}
+}