1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/unistd.h>
  3#include <linux/kernel.h>
  4#include <linux/fs.h>
  5#include <linux/minix_fs.h>
 
  6#include <linux/romfs_fs.h>
  7#include <linux/initrd.h>
  8#include <linux/sched.h>
  9#include <linux/freezer.h>
 10#include <linux/kmod.h>
 11#include <uapi/linux/mount.h>
 12
 13#include "do_mounts.h"
 14
 15unsigned long initrd_start, initrd_end;
 16int initrd_below_start_ok;
 17static unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */
 
 18static int __initdata mount_initrd = 1;
 19
 20phys_addr_t phys_initrd_start __initdata;
 21unsigned long phys_initrd_size __initdata;
 22
 23#ifdef CONFIG_SYSCTL
 24static struct ctl_table kern_do_mounts_initrd_table[] = {
 25	{
 26		.procname       = "real-root-dev",
 27		.data           = &real_root_dev,
 28		.maxlen         = sizeof(int),
 29		.mode           = 0644,
 30		.proc_handler   = proc_dointvec,
 31	},
 32};
 33
 34static __init int kernel_do_mounts_initrd_sysctls_init(void)
 35{
 36	register_sysctl_init("kernel", kern_do_mounts_initrd_table);
 37	return 0;
 38}
 39late_initcall(kernel_do_mounts_initrd_sysctls_init);
 40#endif /* CONFIG_SYSCTL */
 41
 42static int __init no_initrd(char *str)
 43{
 44	mount_initrd = 0;
 45	return 1;
 46}
 47
 48__setup("noinitrd", no_initrd);
 49
 50static int __init early_initrdmem(char *p)
 51{
 52	phys_addr_t start;
 53	unsigned long size;
 54	char *endp;
 55
 56	start = memparse(p, &endp);
 57	if (*endp == ',') {
 58		size = memparse(endp + 1, NULL);
 59
 60		phys_initrd_start = start;
 61		phys_initrd_size = size;
 62	}
 63	return 0;
 64}
 65early_param("initrdmem", early_initrdmem);
 66
 67static int __init early_initrd(char *p)
 68{
 69	return early_initrdmem(p);
 70}
 71early_param("initrd", early_initrd);
 72
 73static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
 74{
 75	ksys_unshare(CLONE_FS | CLONE_FILES);
 76	console_on_rootfs();
 77	/* move initrd over / and chdir/chroot in initrd root */
 78	init_chdir("/root");
 79	init_mount(".", "/", NULL, MS_MOVE, NULL);
 80	init_chroot(".");
 81	ksys_setsid();
 82	return 0;
 83}
 84
 85static void __init handle_initrd(char *root_device_name)
 86{
 87	struct subprocess_info *info;
 88	static char *argv[] = { "linuxrc", NULL, };
 89	extern char *envp_init[];
 90	int error;
 91
 92	pr_warn("using deprecated initrd support, will be removed in 2021.\n");
 93
 94	real_root_dev = new_encode_dev(ROOT_DEV);
 95	create_dev("/dev/root.old", Root_RAM0);
 96	/* mount initrd on rootfs' /root */
 97	mount_root_generic("/dev/root.old", root_device_name,
 98			   root_mountflags & ~MS_RDONLY);
 99	init_mkdir("/old", 0700);
100	init_chdir("/old");
101
102	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
103					 GFP_KERNEL, init_linuxrc, NULL, NULL);
104	if (!info)
105		return;
106	call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);
 
 
 
 
 
 
 
 
 
 
 
107
108	/* move initrd to rootfs' /old */
109	init_mount("..", ".", NULL, MS_MOVE, NULL);
 
110	/* switch root and cwd back to / of rootfs */
111	init_chroot("..");
 
 
 
112
113	if (new_decode_dev(real_root_dev) == Root_RAM0) {
114		init_chdir("/old");
115		return;
116	}
117
118	init_chdir("/");
119	ROOT_DEV = new_decode_dev(real_root_dev);
120	mount_root(root_device_name);
121
122	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
123	error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
124	if (!error)
125		printk("okay\n");
126	else {
 
127		if (error == -ENOENT)
128			printk("/initrd does not exist. Ignored.\n");
129		else
130			printk("failed\n");
131		printk(KERN_NOTICE "Unmounting old root\n");
132		init_umount("/old", MNT_DETACH);
 
 
 
 
 
 
 
 
133	}
134}
135
136bool __init initrd_load(char *root_device_name)
137{
138	if (mount_initrd) {
139		create_dev("/dev/ram", Root_RAM0);
140		/*
141		 * Load the initrd data into /dev/ram0. Execute it as initrd
142		 * unless /dev/ram0 is supposed to be our actual root device,
143		 * in that case the ram disk is just set up here, and gets
144		 * mounted in the normal path.
145		 */
146		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
147			init_unlink("/initrd.image");
148			handle_initrd(root_device_name);
149			return true;
150		}
151	}
152	init_unlink("/initrd.image");
153	return false;
154}

 
  1#include <linux/unistd.h>
  2#include <linux/kernel.h>
  3#include <linux/fs.h>
  4#include <linux/minix_fs.h>
  5#include <linux/ext2_fs.h>
  6#include <linux/romfs_fs.h>
  7#include <linux/initrd.h>
  8#include <linux/sched.h>
  9#include <linux/freezer.h>
 
 
 10
 11#include "do_mounts.h"
 12
 13unsigned long initrd_start, initrd_end;
 14int initrd_below_start_ok;
 15unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */
 16static int __initdata old_fd, root_fd;
 17static int __initdata mount_initrd = 1;
 18
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 19static int __init no_initrd(char *str)
 20{
 21	mount_initrd = 0;
 22	return 1;
 23}
 24
 25__setup("noinitrd", no_initrd);
 26
 27static int __init do_linuxrc(void *_shell)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 28{
 29	static const char *argv[] = { "linuxrc", NULL, };
 30	extern const char *envp_init[];
 31	const char *shell = _shell;
 32
 33	sys_close(old_fd);sys_close(root_fd);
 34	sys_setsid();
 35	return kernel_execve(shell, argv, envp_init);
 
 
 
 
 
 
 
 36}
 37
 38static void __init handle_initrd(void)
 39{
 
 
 
 40	int error;
 41	int pid;
 
 42
 43	real_root_dev = new_encode_dev(ROOT_DEV);
 44	create_dev("/dev/root.old", Root_RAM0);
 45	/* mount initrd on rootfs' /root */
 46	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
 47	sys_mkdir("/old", 0700);
 48	root_fd = sys_open("/", 0, 0);
 49	old_fd = sys_open("/old", 0, 0);
 50	/* move initrd over / and chdir/chroot in initrd root */
 51	sys_chdir("/root");
 52	sys_mount(".", "/", NULL, MS_MOVE, NULL);
 53	sys_chroot(".");
 54
 55	/*
 56	 * In case that a resume from disk is carried out by linuxrc or one of
 57	 * its children, we need to tell the freezer not to wait for us.
 58	 */
 59	current->flags |= PF_FREEZER_SKIP;
 60
 61	pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
 62	if (pid > 0)
 63		while (pid != sys_wait4(-1, NULL, 0, NULL))
 64			yield();
 65
 66	current->flags &= ~PF_FREEZER_SKIP;
 67
 68	/* move initrd to rootfs' /old */
 69	sys_fchdir(old_fd);
 70	sys_mount("/", ".", NULL, MS_MOVE, NULL);
 71	/* switch root and cwd back to / of rootfs */
 72	sys_fchdir(root_fd);
 73	sys_chroot(".");
 74	sys_close(old_fd);
 75	sys_close(root_fd);
 76
 77	if (new_decode_dev(real_root_dev) == Root_RAM0) {
 78		sys_chdir("/old");
 79		return;
 80	}
 81
 
 82	ROOT_DEV = new_decode_dev(real_root_dev);
 83	mount_root();
 84
 85	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
 86	error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
 87	if (!error)
 88		printk("okay\n");
 89	else {
 90		int fd = sys_open("/dev/root.old", O_RDWR, 0);
 91		if (error == -ENOENT)
 92			printk("/initrd does not exist. Ignored.\n");
 93		else
 94			printk("failed\n");
 95		printk(KERN_NOTICE "Unmounting old root\n");
 96		sys_umount("/old", MNT_DETACH);
 97		printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
 98		if (fd < 0) {
 99			error = fd;
100		} else {
101			error = sys_ioctl(fd, BLKFLSBUF, 0);
102			sys_close(fd);
103		}
104		printk(!error ? "okay\n" : "failed\n");
105	}
106}
107
108int __init initrd_load(void)
109{
110	if (mount_initrd) {
111		create_dev("/dev/ram", Root_RAM0);
112		/*
113		 * Load the initrd data into /dev/ram0. Execute it as initrd
114		 * unless /dev/ram0 is supposed to be our actual root device,
115		 * in that case the ram disk is just set up here, and gets
116		 * mounted in the normal path.
117		 */
118		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
119			sys_unlink("/initrd.image");
120			handle_initrd();
121			return 1;
122		}
123	}
124	sys_unlink("/initrd.image");
125	return 0;
126}