2 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU Lesser General Public License version 2.1
6 * as published by the Free Software Foundation
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
18 #include <sys/mount.h>
19 #include <sys/types.h>
23 #include "../fs-state.h"
25 char const *extroot_prefix = NULL;
27 static int mount_extroot(void)
37 sprintf(block_path, "%s/sbin/block", extroot_prefix);
39 if (stat(block_path, &s))
42 sprintf(kmod_loader, "/sbin/kmodloader %s/etc/modules-boot.d/ %s", extroot_prefix, extroot_prefix);
47 mkdir("/tmp/extroot", 0755);
48 execl(block_path, block_path, "extroot", NULL);
53 waitpid(pid, &status, 0);
54 if (!WEXITSTATUS(status)) {
55 if (find_mount("/tmp/extroot/mnt")) {
56 mount("/dev/root", "/", NULL, MS_NOATIME | MS_REMOUNT | MS_RDONLY, 0);
58 mkdir("/tmp/extroot/mnt/proc", 0755);
59 mkdir("/tmp/extroot/mnt/dev", 0755);
60 mkdir("/tmp/extroot/mnt/sys", 0755);
61 mkdir("/tmp/extroot/mnt/tmp", 0755);
62 mkdir("/tmp/extroot/mnt/rom", 0755);
64 if (mount_move("/tmp/extroot", "", "/mnt")) {
65 fprintf(stderr, "moving pivotroot failed - continue normal boot\n");
66 umount("/tmp/extroot/mnt");
67 } else if (pivot("/mnt", "/rom")) {
68 fprintf(stderr, "switching to pivotroot failed - continue normal boot\n");
71 umount("/tmp/overlay");
72 rmdir("/tmp/overlay");
73 rmdir("/tmp/extroot/mnt");
74 rmdir("/tmp/extroot");
77 } else if (find_mount("/tmp/extroot/overlay")) {
78 if (mount_move("/tmp/extroot", "", "/overlay")) {
79 fprintf(stderr, "moving extroot failed - continue normal boot\n");
80 umount("/tmp/extroot/overlay");
81 } else if (fopivot("/overlay", "/rom")) {
82 fprintf(stderr, "switching to extroot failed - continue normal boot\n");
85 umount("/tmp/overlay");
86 rmdir("/tmp/overlay");
87 rmdir("/tmp/extroot/overlay");
88 rmdir("/tmp/extroot");
97 static struct backend extroot_backend = {
99 .mount = mount_extroot,
101 BACKEND(extroot_backend);