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>
24 #include "libfstools.h"
26 char const *extroot_prefix = NULL;
29 * This will execute "block extroot" and make use of mounted extroot or return
32 int mount_extroot(void)
36 char kmod_loader[128];
44 /* try finding the library directory */
45 snprintf(ldlib_path, sizeof(ldlib_path), "%s/upper/lib", extroot_prefix);
47 if (stat(ldlib_path, &s) || !S_ISDIR(s.st_mode))
48 snprintf(ldlib_path, sizeof(ldlib_path), "%s/lib", extroot_prefix);
50 /* try finding the block executable */
51 snprintf(block_path, sizeof(block_path), "%s/upper/sbin/block", extroot_prefix);
53 if (stat(block_path, &s) || !S_ISREG(s.st_mode))
54 snprintf(block_path, sizeof(block_path), "%s/sbin/block", extroot_prefix);
56 if (stat(block_path, &s) || !S_ISREG(s.st_mode))
57 snprintf(block_path, sizeof(block_path), "/sbin/block");
59 if (stat(block_path, &s) || !S_ISREG(s.st_mode))
62 /* set LD_LIBRARY_PATH env var and load kmods from overlay if we found a lib directory there */
63 if (!stat(ldlib_path, &s) && S_ISDIR(s.st_mode)) {
64 setenv("LD_LIBRARY_PATH", ldlib_path, 1);
65 kmod_prefix = dirname(ldlib_path);
66 sprintf(kmod_loader, "/sbin/kmodloader %s/etc/modules-boot.d/ %s", kmod_prefix, kmod_prefix);
72 mkdir("/tmp/extroot", 0755);
73 execl(block_path, block_path, "extroot", NULL);
78 waitpid(pid, &status, 0);
79 if (!WEXITSTATUS(status)) {
80 if (find_mount("/tmp/extroot/mnt")) {
81 mount("/dev/root", "/", NULL, MS_NOATIME | MS_REMOUNT | MS_RDONLY, 0);
83 mkdir("/tmp/extroot/mnt/proc", 0755);
84 mkdir("/tmp/extroot/mnt/dev", 0755);
85 mkdir("/tmp/extroot/mnt/sys", 0755);
86 mkdir("/tmp/extroot/mnt/tmp", 0755);
87 mkdir("/tmp/extroot/mnt/rom", 0755);
89 if (mount_move("/tmp/extroot", "", "/mnt")) {
90 fprintf(stderr, "moving pivotroot failed - continue normal boot\n");
91 umount("/tmp/extroot/mnt");
92 } else if (pivot("/mnt", "/rom")) {
93 fprintf(stderr, "switching to pivotroot failed - continue normal boot\n");
96 umount("/tmp/overlay");
97 rmdir("/tmp/overlay");
98 rmdir("/tmp/extroot/mnt");
99 rmdir("/tmp/extroot");
102 } else if (find_mount("/tmp/extroot/overlay")) {
103 if (mount_move("/tmp/extroot", "", "/overlay")) {
104 fprintf(stderr, "moving extroot failed - continue normal boot\n");
105 umount("/tmp/extroot/overlay");
106 } else if (fopivot("/overlay", "/rom")) {
107 fprintf(stderr, "switching to extroot failed - continue normal boot\n");
110 umount("/tmp/overlay");
111 rmdir("/tmp/overlay");
112 rmdir("/tmp/extroot/overlay");
113 rmdir("/tmp/extroot");