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// SPDX-License-Identifier: GPL-2.0
#include <linux/unistd.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/romfs_fs.h>
#include <linux/initrd.h>
#include <linux/sched.h>
#include <linux/freezer.h>
#include <linux/kmod.h>
#include <uapi/linux/mount.h>
#include "do_mounts.h"
unsigned long initrd_start, initrd_end;
int initrd_below_start_ok;
static unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
static int __initdata mount_initrd = 1;
phys_addr_t phys_initrd_start __initdata;
unsigned long phys_initrd_size __initdata;
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_do_mounts_initrd_table[] = {
{
.procname = "real-root-dev",
.data = &real_root_dev,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static __init int kernel_do_mounts_initrd_sysctls_init(void)
{
register_sysctl_init("kernel", kern_do_mounts_initrd_table);
return 0;
}
late_initcall(kernel_do_mounts_initrd_sysctls_init);
#endif /* CONFIG_SYSCTL */
static int __init no_initrd(char *str)
{
mount_initrd = 0;
return 1;
}
__setup("noinitrd", no_initrd);
static int __init early_initrdmem(char *p)
{
phys_addr_t start;
unsigned long size;
char *endp;
start = memparse(p, &endp);
if (*endp == ',') {
size = memparse(endp + 1, NULL);
phys_initrd_start = start;
phys_initrd_size = size;
}
return 0;
}
early_param("initrdmem", early_initrdmem);
static int __init early_initrd(char *p)
{
return early_initrdmem(p);
}
early_param("initrd", early_initrd);
static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
{
ksys_unshare(CLONE_FS | CLONE_FILES);
console_on_rootfs();
/* move initrd over / and chdir/chroot in initrd root */
init_chdir("/root");
init_mount(".", "/", NULL, MS_MOVE, NULL);
init_chroot(".");
ksys_setsid();
return 0;
}
static void __init handle_initrd(char *root_device_name)
{
struct subprocess_info *info;
static char *argv[] = { "linuxrc", NULL, };
extern char *envp_init[];
int error;
pr_warn("using deprecated initrd support, will be removed in 2021.\n");
real_root_dev = new_encode_dev(ROOT_DEV);
create_dev("/dev/root.old", Root_RAM0);
/* mount initrd on rootfs' /root */
mount_root_generic("/dev/root.old", root_device_name,
root_mountflags & ~MS_RDONLY);
init_mkdir("/old", 0700);
init_chdir("/old");
info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
GFP_KERNEL, init_linuxrc, NULL, NULL);
if (!info)
return;
call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);
/* move initrd to rootfs' /old */
init_mount("..", ".", NULL, MS_MOVE, NULL);
/* switch root and cwd back to / of rootfs */
init_chroot("..");
if (new_decode_dev(real_root_dev) == Root_RAM0) {
init_chdir("/old");
return;
}
init_chdir("/");
ROOT_DEV = new_decode_dev(real_root_dev);
mount_root(root_device_name);
printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
if (!error)
printk("okay\n");
else {
if (error == -ENOENT)
printk("/initrd does not exist. Ignored.\n");
else
printk("failed\n");
printk(KERN_NOTICE "Unmounting old root\n");
init_umount("/old", MNT_DETACH);
}
}
bool __init initrd_load(char *root_device_name)
{
if (mount_initrd) {
create_dev("/dev/ram", Root_RAM0);
/*
* Load the initrd data into /dev/ram0. Execute it as initrd
* unless /dev/ram0 is supposed to be our actual root device,
* in that case the ram disk is just set up here, and gets
* mounted in the normal path.
*/
if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
init_unlink("/initrd.image");
handle_initrd(root_device_name);
return true;
}
}
init_unlink("/initrd.image");
return false;
}
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