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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * Many of the syscalls used in this file expect some of the arguments | |
4 | * to be __user pointers not __kernel pointers. To limit the sparse | |
5 | * noise, turn off sparse checking for this file. | |
6 | */ | |
7 | #ifdef __CHECKER__ | |
8 | #undef __CHECKER__ | |
9 | #warning "Sparse checking disabled for this file" | |
10 | #endif | |
11 | ||
12 | #include <linux/unistd.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/fs.h> | |
15 | #include <linux/minix_fs.h> | |
16 | #include <linux/romfs_fs.h> | |
17 | #include <linux/initrd.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/freezer.h> | |
20 | #include <linux/kmod.h> | |
21 | ||
22 | #include "do_mounts.h" | |
23 | ||
24 | unsigned long initrd_start, initrd_end; | |
25 | int initrd_below_start_ok; | |
26 | unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */ | |
27 | static int __initdata mount_initrd = 1; | |
28 | ||
29 | static int __init no_initrd(char *str) | |
30 | { | |
31 | mount_initrd = 0; | |
32 | return 1; | |
33 | } | |
34 | ||
35 | __setup("noinitrd", no_initrd); | |
36 | ||
37 | static int init_linuxrc(struct subprocess_info *info, struct cred *new) | |
38 | { | |
39 | sys_unshare(CLONE_FS | CLONE_FILES); | |
40 | /* stdin/stdout/stderr for /linuxrc */ | |
41 | sys_open("/dev/console", O_RDWR, 0); | |
42 | sys_dup(0); | |
43 | sys_dup(0); | |
44 | /* move initrd over / and chdir/chroot in initrd root */ | |
45 | sys_chdir("/root"); | |
46 | sys_mount(".", "/", NULL, MS_MOVE, NULL); | |
47 | sys_chroot("."); | |
48 | sys_setsid(); | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static void __init handle_initrd(void) | |
53 | { | |
54 | struct subprocess_info *info; | |
55 | static char *argv[] = { "linuxrc", NULL, }; | |
56 | extern char *envp_init[]; | |
57 | int error; | |
58 | ||
59 | real_root_dev = new_encode_dev(ROOT_DEV); | |
60 | create_dev("/dev/root.old", Root_RAM0); | |
61 | /* mount initrd on rootfs' /root */ | |
62 | mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); | |
63 | sys_mkdir("/old", 0700); | |
64 | sys_chdir("/old"); | |
65 | ||
66 | /* try loading default modules from initrd */ | |
67 | load_default_modules(); | |
68 | ||
69 | /* | |
70 | * In case that a resume from disk is carried out by linuxrc or one of | |
71 | * its children, we need to tell the freezer not to wait for us. | |
72 | */ | |
73 | current->flags |= PF_FREEZER_SKIP; | |
74 | ||
75 | info = call_usermodehelper_setup("/linuxrc", argv, envp_init, | |
76 | GFP_KERNEL, init_linuxrc, NULL, NULL); | |
77 | if (!info) | |
78 | return; | |
79 | call_usermodehelper_exec(info, UMH_WAIT_PROC); | |
80 | ||
81 | current->flags &= ~PF_FREEZER_SKIP; | |
82 | ||
83 | /* move initrd to rootfs' /old */ | |
84 | sys_mount("..", ".", NULL, MS_MOVE, NULL); | |
85 | /* switch root and cwd back to / of rootfs */ | |
86 | sys_chroot(".."); | |
87 | ||
88 | if (new_decode_dev(real_root_dev) == Root_RAM0) { | |
89 | sys_chdir("/old"); | |
90 | return; | |
91 | } | |
92 | ||
93 | sys_chdir("/"); | |
94 | ROOT_DEV = new_decode_dev(real_root_dev); | |
95 | mount_root(); | |
96 | ||
97 | printk(KERN_NOTICE "Trying to move old root to /initrd ... "); | |
98 | error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL); | |
99 | if (!error) | |
100 | printk("okay\n"); | |
101 | else { | |
102 | int fd = sys_open("/dev/root.old", O_RDWR, 0); | |
103 | if (error == -ENOENT) | |
104 | printk("/initrd does not exist. Ignored.\n"); | |
105 | else | |
106 | printk("failed\n"); | |
107 | printk(KERN_NOTICE "Unmounting old root\n"); | |
108 | sys_umount("/old", MNT_DETACH); | |
109 | printk(KERN_NOTICE "Trying to free ramdisk memory ... "); | |
110 | if (fd < 0) { | |
111 | error = fd; | |
112 | } else { | |
113 | error = sys_ioctl(fd, BLKFLSBUF, 0); | |
114 | sys_close(fd); | |
115 | } | |
116 | printk(!error ? "okay\n" : "failed\n"); | |
117 | } | |
118 | } | |
119 | ||
120 | bool __init initrd_load(void) | |
121 | { | |
122 | if (mount_initrd) { | |
123 | create_dev("/dev/ram", Root_RAM0); | |
124 | /* | |
125 | * Load the initrd data into /dev/ram0. Execute it as initrd | |
126 | * unless /dev/ram0 is supposed to be our actual root device, | |
127 | * in that case the ram disk is just set up here, and gets | |
128 | * mounted in the normal path. | |
129 | */ | |
130 | if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) { | |
131 | sys_unlink("/initrd.image"); | |
132 | handle_initrd(); | |
133 | return true; | |
134 | } | |
135 | } | |
136 | sys_unlink("/initrd.image"); | |
137 | return false; | |
138 | } |