// SPDX-License-Identifier: GPL-2.0-only

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/ctype.h>

#include <linux/fd.h>

#include <linux/tty.h>

#include <linux/suspend.h>

#include <linux/root_dev.h>

#include <linux/security.h>

#include <linux/delay.h>

#include <linux/mount.h>

#include <linux/device.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/initrd.h>

#include <linux/async.h>

#include <linux/fs_struct.h>

#include <linux/slab.h>

#include <linux/ramfs.h>

#include <linux/shmem_fs.h>

#include <linux/ktime.h>

#include <linux/nfs_fs.h>

#include <linux/nfs_fs_sb.h>

#include <linux/nfs_mount.h>

#include <linux/raid/detect.h>

#include <uapi/linux/mount.h>

#include "do_mounts.h"

int root_mountflags = MS_RDONLY | MS_SILENT;

static char __initdata saved_root_name[64];

static int root_wait;

dev_t ROOT_DEV;

static int __init readonly(char *str)

{

if (*str)

return 0;

root_mountflags |= MS_RDONLY;

return 1;

}

static int __init readwrite(char *str)

{

if (*str)

return 0;

root_mountflags &= ~MS_RDONLY;

return 1;

}

__setup("ro", readonly);

__setup("rw", readwrite);

static int __init root_dev_setup(char *line)

{

strscpy(saved_root_name, line, sizeof(saved_root_name));

return 1;

}

__setup("root=", root_dev_setup);

static int __init rootwait_setup(char *str)

{

if (*str)

return 0;

root_wait = -1;

return 1;

}

__setup("rootwait", rootwait_setup);

static int __init rootwait_timeout_setup(char *str)

{

int sec;

if (kstrtoint(str, 0, &sec) || sec < 0) {

pr_warn("ignoring invalid rootwait value\n");

goto ignore;

}

if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {

pr_warn("ignoring excessive rootwait value\n");

goto ignore;

}

return 1;

ignore:

/* Fallback to indefinite wait */

root_wait = -1;

return 1;

}

__setup("rootwait=", rootwait_timeout_setup);

static char * __initdata root_mount_data;

static int __init root_data_setup(char *str)

{

root_mount_data = str;

return 1;

}

static char * __initdata root_fs_names;

static int __init fs_names_setup(char *str)

{

root_fs_names = str;

return 1;

}

static unsigned int __initdata root_delay;

static int __init root_delay_setup(char *str)

{

if (kstrtouint(str, 0, &root_delay))

return 0;

return 1;

}

__setup("rootflags=", root_data_setup);

__setup("rootfstype=", fs_names_setup);

__setup("rootdelay=", root_delay_setup);

/* This can return zero length strings. Caller should check */

static int __init split_fs_names(char *page, size_t size)

{

int count = 1;

char *p = page;

strscpy(p, root_fs_names, size);

while (*p++) {

if (p[-1] == ',') {

p[-1] = '\0';

count++;

}

}

return count;

}

static int __init do_mount_root(const char *name, const char *fs,

const int flags, const void *data)

{

struct super_block *s;

struct page *p = NULL;

char *data_page = NULL;

int ret;

if (data) {

/* init_mount() requires a full page as fifth argument */

p = alloc_page(GFP_KERNEL);

if (!p)

return -ENOMEM;

data_page = page_address(p);

strscpy_pad(data_page, data, PAGE_SIZE);

}

ret = init_mount(name, "/root", fs, flags, data_page);

if (ret)

goto out;

init_chdir("/root");

s = current->fs->pwd.dentry->d_sb;

ROOT_DEV = s->s_dev;

printk(KERN_INFO

"VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",

s->s_type->name,

sb_rdonly(s) ? " readonly" : "",

MAJOR(ROOT_DEV), MINOR(ROOT_DEV));

out:

if (p)

put_page(p);

return ret;

}

void __init mount_root_generic(char *name, char *pretty_name, int flags)

{

struct page *page = alloc_page(GFP_KERNEL);

char *fs_names = page_address(page);

char *p;

char b[BDEVNAME_SIZE];

int num_fs, i;

scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",

MAJOR(ROOT_DEV), MINOR(ROOT_DEV));

if (root_fs_names)

num_fs = split_fs_names(fs_names, PAGE_SIZE);

else

num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);

retry:

for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {

int err;

if (!*p)

continue;

err = do_mount_root(name, p, flags, root_mount_data);

switch (err) {

case 0:

goto out;

case -EACCES:

case -EINVAL:

#ifdef CONFIG_BLOCK

init_flush_fput();

#endif

continue;

}

/*

* Allow the user to distinguish between failed sys_open

* and bad superblock on root device.

* and give them a list of the available devices

*/

printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",

pretty_name, b, err);

printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");

printk_all_partitions();

if (root_fs_names)

num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);

if (!num_fs)

pr_err("Can't find any bdev filesystem to be used for mount!\n");

else {

pr_err("List of all bdev filesystems:\n");

for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)

pr_err(" %s", p);

pr_err("\n");

}

panic("VFS: Unable to mount root fs on %s", b);

}

if (!(flags & SB_RDONLY)) {

flags |= SB_RDONLY;

goto retry;

}

printk("List of all partitions:\n");

printk_all_partitions();

printk("No filesystem could mount root, tried: ");

for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)

printk(" %s", p);

printk("\n");

panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);

out:

put_page(page);

}

#ifdef CONFIG_ROOT_NFS

#define NFSROOT_TIMEOUT_MIN 5

#define NFSROOT_TIMEOUT_MAX 30

#define NFSROOT_RETRY_MAX 5

static void __init mount_nfs_root(void)

{

char *root_dev, *root_data;

unsigned int timeout;

int try;

if (nfs_root_data(&root_dev, &root_data))

goto fail;

/*

* The server or network may not be ready, so try several

* times. Stop after a few tries in case the client wants

* to fall back to other boot methods.

*/

timeout = NFSROOT_TIMEOUT_MIN;

for (try = 1; ; try++) {

if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))

return;

if (try > NFSROOT_RETRY_MAX)

break;

/* Wait, in case the server refused us immediately */

ssleep(timeout);

timeout <<= 1;

if (timeout > NFSROOT_TIMEOUT_MAX)

timeout = NFSROOT_TIMEOUT_MAX;

}

fail:

pr_err("VFS: Unable to mount root fs via NFS.\n");

}

#else

static inline void mount_nfs_root(void)

{

}

#endif /* CONFIG_ROOT_NFS */

#ifdef CONFIG_CIFS_ROOT

#define CIFSROOT_TIMEOUT_MIN 5

#define CIFSROOT_TIMEOUT_MAX 30

#define CIFSROOT_RETRY_MAX 5

static void __init mount_cifs_root(void)

{

char *root_dev, *root_data;

unsigned int timeout;

int try;

if (cifs_root_data(&root_dev, &root_data))

goto fail;

timeout = CIFSROOT_TIMEOUT_MIN;

for (try = 1; ; try++) {

if (!do_mount_root(root_dev, "cifs", root_mountflags,

root_data))

return;

if (try > CIFSROOT_RETRY_MAX)

break;

ssleep(timeout);

timeout <<= 1;

if (timeout > CIFSROOT_TIMEOUT_MAX)

timeout = CIFSROOT_TIMEOUT_MAX;

}

fail:

pr_err("VFS: Unable to mount root fs via SMB.\n");

}

#else

static inline void mount_cifs_root(void)

{

}

#endif /* CONFIG_CIFS_ROOT */

static bool __init fs_is_nodev(char *fstype)

{

struct file_system_type *fs = get_fs_type(fstype);

bool ret = false;

if (fs) {

ret = !(fs->fs_flags & FS_REQUIRES_DEV);

put_filesystem(fs);

}

return ret;

}

static int __init mount_nodev_root(char *root_device_name)

{

char *fs_names, *fstype;

int err = -EINVAL;

int num_fs, i;

fs_names = (void *)__get_free_page(GFP_KERNEL);

if (!fs_names)

return -EINVAL;

num_fs = split_fs_names(fs_names, PAGE_SIZE);

for (i = 0, fstype = fs_names; i < num_fs;

i++, fstype += strlen(fstype) + 1) {

if (!*fstype)

continue;

if (!fs_is_nodev(fstype))

continue;

err = do_mount_root(root_device_name, fstype, root_mountflags,

root_mount_data);

if (!err)

break;

}

free_page((unsigned long)fs_names);

return err;

}

#ifdef CONFIG_BLOCK

static void __init mount_block_root(char *root_device_name)

{

int err = create_dev("/dev/root", ROOT_DEV);

if (err < 0)

pr_emerg("Failed to create /dev/root: %d\n", err);

mount_root_generic("/dev/root", root_device_name, root_mountflags);

}

#else

static inline void mount_block_root(char *root_device_name)

{

}

#endif /* CONFIG_BLOCK */

void __init mount_root(char *root_device_name)

{

switch (ROOT_DEV) {

case Root_NFS:

mount_nfs_root();

break;

case Root_CIFS:

mount_cifs_root();

break;

case Root_Generic:

mount_root_generic(root_device_name, root_device_name,

root_mountflags);

break;

case 0:

if (root_device_name && root_fs_names &&

mount_nodev_root(root_device_name) == 0)

break;

fallthrough;

default:

mount_block_root(root_device_name);

break;

}

}

/* wait for any asynchronous scanning to complete */

static void __init wait_for_root(char *root_device_name)

{

ktime_t end;

if (ROOT_DEV != 0)

return;

pr_info("Waiting for root device %s...\n", root_device_name);

end = ktime_add_ms(ktime_get_raw(), root_wait);

while (!driver_probe_done() ||

early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {

msleep(5);

if (root_wait > 0 && ktime_after(ktime_get_raw(), end))

break;

}

async_synchronize_full();

}

static dev_t __init parse_root_device(char *root_device_name)

{

int error;

dev_t dev;

if (!strncmp(root_device_name, "mtd", 3) ||

!strncmp(root_device_name, "ubi", 3))

return Root_Generic;

if (strcmp(root_device_name, "/dev/nfs") == 0)

return Root_NFS;

if (strcmp(root_device_name, "/dev/cifs") == 0)

return Root_CIFS;

if (strcmp(root_device_name, "/dev/ram") == 0)

return Root_RAM0;

error = early_lookup_bdev(root_device_name, &dev);

if (error) {

if (error == -EINVAL && root_wait) {

pr_err("Disabling rootwait; root= is invalid.\n");

root_wait = 0;

}

return 0;

}

return dev;

}

/*

* Prepare the namespace - decide what/where to mount, load ramdisks, etc.

*/

void __init prepare_namespace(void)

{

if (root_delay) {

printk(KERN_INFO "Waiting %d sec before mounting root device...\n",

root_delay);

ssleep(root_delay);

}

/*

* wait for the known devices to complete their probing

*

* Note: this is a potential source of long boot delays.

* For example, it is not atypical to wait 5 seconds here

* for the touchpad of a laptop to initialize.

*/

wait_for_device_probe();

md_run_setup();

if (saved_root_name[0])

ROOT_DEV = parse_root_device(saved_root_name);

initrd_load();

if (root_wait)

wait_for_root(saved_root_name);

mount_root(saved_root_name);

devtmpfs_mount();

if (init_pivot_root(".", ".")) {

pr_err("VFS: Failed to pivot into new rootfs\n");

return;

}

if (init_umount(".", MNT_DETACH)) {

pr_err("VFS: Failed to unmount old rootfs\n");

return;

}

pr_info("VFS: Pivoted into new rootfs\n");

}

static bool is_tmpfs;

static int rootfs_init_fs_context(struct fs_context *fc)

{

if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)

return shmem_init_fs_context(fc);

return ramfs_init_fs_context(fc);

}

struct file_system_type rootfs_fs_type = {

.name = "rootfs",

.init_fs_context = rootfs_init_fs_context,

.kill_sb = kill_anon_super,

};

void __init init_rootfs(void)

{

if (IS_ENABLED(CONFIG_TMPFS)) {

if (!saved_root_name[0] && !root_fs_names)

is_tmpfs = true;

else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))

is_tmpfs = true;

}

}