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// 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};
 34
 35static __init int kernel_do_mounts_initrd_sysctls_init(void)
 36{
 37	register_sysctl_init("kernel", kern_do_mounts_initrd_table);
 38	return 0;
 39}
 40late_initcall(kernel_do_mounts_initrd_sysctls_init);
 41#endif /* CONFIG_SYSCTL */
 42
 43static int __init no_initrd(char *str)
 44{
 45	mount_initrd = 0;
 46	return 1;
 47}
 48
 49__setup("noinitrd", no_initrd);
 50
 51static int __init early_initrdmem(char *p)
 52{
 53	phys_addr_t start;
 54	unsigned long size;
 55	char *endp;
 56
 57	start = memparse(p, &endp);
 58	if (*endp == ',') {
 59		size = memparse(endp + 1, NULL);
 60
 61		phys_initrd_start = start;
 62		phys_initrd_size = size;
 63	}
 64	return 0;
 65}
 66early_param("initrdmem", early_initrdmem);
 67
 68static int __init early_initrd(char *p)
 69{
 70	return early_initrdmem(p);
 71}
 72early_param("initrd", early_initrd);
 73
 74static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
 75{
 76	ksys_unshare(CLONE_FS | CLONE_FILES);
 77	console_on_rootfs();
 78	/* move initrd over / and chdir/chroot in initrd root */
 79	init_chdir("/root");
 80	init_mount(".", "/", NULL, MS_MOVE, NULL);
 81	init_chroot(".");
 82	ksys_setsid();
 83	return 0;
 84}
 85
 86static void __init handle_initrd(char *root_device_name)
 87{
 88	struct subprocess_info *info;
 89	static char *argv[] = { "linuxrc", NULL, };
 90	extern char *envp_init[];
 91	int error;
 92
 93	pr_warn("using deprecated initrd support, will be removed in 2021.\n");
 94
 95	real_root_dev = new_encode_dev(ROOT_DEV);
 96	create_dev("/dev/root.old", Root_RAM0);
 97	/* mount initrd on rootfs' /root */
 98	mount_root_generic("/dev/root.old", root_device_name,
 99			   root_mountflags & ~MS_RDONLY);
100	init_mkdir("/old", 0700);
101	init_chdir("/old");
102
103	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
104					 GFP_KERNEL, init_linuxrc, NULL, NULL);
105	if (!info)
106		return;
107	call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);
108
109	/* move initrd to rootfs' /old */
110	init_mount("..", ".", NULL, MS_MOVE, NULL);
111	/* switch root and cwd back to / of rootfs */
112	init_chroot("..");
113
114	if (new_decode_dev(real_root_dev) == Root_RAM0) {
115		init_chdir("/old");
116		return;
117	}
118
119	init_chdir("/");
120	ROOT_DEV = new_decode_dev(real_root_dev);
121	mount_root(root_device_name);
122
123	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
124	error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
125	if (!error)
126		printk("okay\n");
127	else {
128		if (error == -ENOENT)
129			printk("/initrd does not exist. Ignored.\n");
130		else
131			printk("failed\n");
132		printk(KERN_NOTICE "Unmounting old root\n");
133		init_umount("/old", MNT_DETACH);
134	}
135}
136
137bool __init initrd_load(char *root_device_name)
138{
139	if (mount_initrd) {
140		create_dev("/dev/ram", Root_RAM0);
141		/*
142		 * Load the initrd data into /dev/ram0. Execute it as initrd
143		 * unless /dev/ram0 is supposed to be our actual root device,
144		 * in that case the ram disk is just set up here, and gets
145		 * mounted in the normal path.
146		 */
147		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
148			init_unlink("/initrd.image");
149			handle_initrd(root_device_name);
150			return true;
151		}
152	}
153	init_unlink("/initrd.image");
154	return false;
155}