| // 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/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 root_device_name; |
| static char __initdata saved_root_name[64]; |
| static int root_wait; |
| |
| dev_t ROOT_DEV; |
| |
| static int __init load_ramdisk(char *str) |
| { |
| pr_warn("ignoring the deprecated load_ramdisk= option\n"); |
| return 1; |
| } |
| __setup("load_ramdisk=", load_ramdisk); |
| |
| 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); |
| |
| #ifdef CONFIG_BLOCK |
| struct uuidcmp { |
| const char *uuid; |
| int len; |
| }; |
| |
| /** |
| * match_dev_by_uuid - callback for finding a partition using its uuid |
| * @dev: device passed in by the caller |
| * @data: opaque pointer to the desired struct uuidcmp to match |
| * |
| * Returns 1 if the device matches, and 0 otherwise. |
| */ |
| static int match_dev_by_uuid(struct device *dev, const void *data) |
| { |
| struct block_device *bdev = dev_to_bdev(dev); |
| const struct uuidcmp *cmp = data; |
| |
| if (!bdev->bd_meta_info || |
| strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len)) |
| return 0; |
| return 1; |
| } |
| |
| /** |
| * devt_from_partuuid - looks up the dev_t of a partition by its UUID |
| * @uuid_str: char array containing ascii UUID |
| * |
| * The function will return the first partition which contains a matching |
| * UUID value in its partition_meta_info struct. This does not search |
| * by filesystem UUIDs. |
| * |
| * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be |
| * extracted and used as an offset from the partition identified by the UUID. |
| * |
| * Returns the matching dev_t on success or 0 on failure. |
| */ |
| static dev_t devt_from_partuuid(const char *uuid_str) |
| { |
| struct uuidcmp cmp; |
| struct device *dev = NULL; |
| dev_t devt = 0; |
| int offset = 0; |
| char *slash; |
| |
| cmp.uuid = uuid_str; |
| |
| slash = strchr(uuid_str, '/'); |
| /* Check for optional partition number offset attributes. */ |
| if (slash) { |
| char c = 0; |
| |
| /* Explicitly fail on poor PARTUUID syntax. */ |
| if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1) |
| goto clear_root_wait; |
| cmp.len = slash - uuid_str; |
| } else { |
| cmp.len = strlen(uuid_str); |
| } |
| |
| if (!cmp.len) |
| goto clear_root_wait; |
| |
| dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid); |
| if (!dev) |
| return 0; |
| |
| if (offset) { |
| /* |
| * Attempt to find the requested partition by adding an offset |
| * to the partition number found by UUID. |
| */ |
| devt = part_devt(dev_to_disk(dev), |
| dev_to_bdev(dev)->bd_partno + offset); |
| } else { |
| devt = dev->devt; |
| } |
| |
| put_device(dev); |
| return devt; |
| |
| clear_root_wait: |
| pr_err("VFS: PARTUUID= is invalid.\n" |
| "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); |
| if (root_wait) |
| pr_err("Disabling rootwait; root= is invalid.\n"); |
| root_wait = 0; |
| return 0; |
| } |
| |
| /** |
| * match_dev_by_label - callback for finding a partition using its label |
| * @dev: device passed in by the caller |
| * @data: opaque pointer to the label to match |
| * |
| * Returns 1 if the device matches, and 0 otherwise. |
| */ |
| static int match_dev_by_label(struct device *dev, const void *data) |
| { |
| struct block_device *bdev = dev_to_bdev(dev); |
| const char *label = data; |
| |
| if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname)) |
| return 0; |
| return 1; |
| } |
| |
| static dev_t devt_from_partlabel(const char *label) |
| { |
| struct device *dev; |
| dev_t devt = 0; |
| |
| dev = class_find_device(&block_class, NULL, label, &match_dev_by_label); |
| if (dev) { |
| devt = dev->devt; |
| put_device(dev); |
| } |
| |
| return devt; |
| } |
| |
| static dev_t devt_from_devname(const char *name) |
| { |
| dev_t devt = 0; |
| int part; |
| char s[32]; |
| char *p; |
| |
| if (strlen(name) > 31) |
| return 0; |
| strcpy(s, name); |
| for (p = s; *p; p++) { |
| if (*p == '/') |
| *p = '!'; |
| } |
| |
| devt = blk_lookup_devt(s, 0); |
| if (devt) |
| return devt; |
| |
| /* |
| * Try non-existent, but valid partition, which may only exist after |
| * opening the device, like partitioned md devices. |
| */ |
| while (p > s && isdigit(p[-1])) |
| p--; |
| if (p == s || !*p || *p == '0') |
| return 0; |
| |
| /* try disk name without <part number> */ |
| part = simple_strtoul(p, NULL, 10); |
| *p = '\0'; |
| devt = blk_lookup_devt(s, part); |
| if (devt) |
| return devt; |
| |
| /* try disk name without p<part number> */ |
| if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') |
| return 0; |
| p[-1] = '\0'; |
| return blk_lookup_devt(s, part); |
| } |
| #endif /* CONFIG_BLOCK */ |
| |
| static dev_t devt_from_devnum(const char *name) |
| { |
| unsigned maj, min, offset; |
| dev_t devt = 0; |
| char *p, dummy; |
| |
| if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 || |
| sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) { |
| devt = MKDEV(maj, min); |
| if (maj != MAJOR(devt) || min != MINOR(devt)) |
| return 0; |
| } else { |
| devt = new_decode_dev(simple_strtoul(name, &p, 16)); |
| if (*p) |
| return 0; |
| } |
| |
| return devt; |
| } |
| |
| /* |
| * Convert a name into device number. We accept the following variants: |
| * |
| * 1) <hex_major><hex_minor> device number in hexadecimal represents itself |
| * no leading 0x, for example b302. |
| * 2) /dev/nfs represents Root_NFS (0xff) |
| * 3) /dev/<disk_name> represents the device number of disk |
| * 4) /dev/<disk_name><decimal> represents the device number |
| * of partition - device number of disk plus the partition number |
| * 5) /dev/<disk_name>p<decimal> - same as the above, that form is |
| * used when disk name of partitioned disk ends on a digit. |
| * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the |
| * unique id of a partition if the partition table provides it. |
| * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS |
| * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- |
| * filled hex representation of the 32-bit "NT disk signature", and PP |
| * is a zero-filled hex representation of the 1-based partition number. |
| * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to |
| * a partition with a known unique id. |
| * 8) <major>:<minor> major and minor number of the device separated by |
| * a colon. |
| * 9) PARTLABEL=<name> with name being the GPT partition label. |
| * MSDOS partitions do not support labels! |
| * 10) /dev/cifs represents Root_CIFS (0xfe) |
| * |
| * If name doesn't have fall into the categories above, we return (0,0). |
| * block_class is used to check if something is a disk name. If the disk |
| * name contains slashes, the device name has them replaced with |
| * bangs. |
| */ |
| dev_t name_to_dev_t(const char *name) |
| { |
| if (strcmp(name, "/dev/nfs") == 0) |
| return Root_NFS; |
| if (strcmp(name, "/dev/cifs") == 0) |
| return Root_CIFS; |
| if (strcmp(name, "/dev/ram") == 0) |
| return Root_RAM0; |
| #ifdef CONFIG_BLOCK |
| if (strncmp(name, "PARTUUID=", 9) == 0) |
| return devt_from_partuuid(name + 9); |
| if (strncmp(name, "PARTLABEL=", 10) == 0) |
| return devt_from_partlabel(name + 10); |
| if (strncmp(name, "/dev/", 5) == 0) |
| return devt_from_devname(name + 5); |
| #endif |
| return devt_from_devnum(name); |
| } |
| EXPORT_SYMBOL_GPL(name_to_dev_t); |
| |
| 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 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) |
| { |
| root_delay = simple_strtoul(str, NULL, 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, char *names) |
| { |
| 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); |
| /* zero-pad. init_mount() will make sure it's terminated */ |
| strncpy(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_block_root(char *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, root_fs_names); |
| 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: |
| 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", |
| root_device_name, b, err); |
| printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); |
| |
| printk_all_partitions(); |
| 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", 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 int __init mount_nfs_root(void) |
| { |
| char *root_dev, *root_data; |
| unsigned int timeout; |
| int try, err; |
| |
| err = nfs_root_data(&root_dev, &root_data); |
| if (err != 0) |
| return 0; |
| |
| /* |
| * 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++) { |
| err = do_mount_root(root_dev, "nfs", |
| root_mountflags, root_data); |
| if (err == 0) |
| return 1; |
| 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; |
| } |
| return 0; |
| } |
| #endif |
| |
| #ifdef CONFIG_CIFS_ROOT |
| |
| extern int cifs_root_data(char **dev, char **opts); |
| |
| #define CIFSROOT_TIMEOUT_MIN 5 |
| #define CIFSROOT_TIMEOUT_MAX 30 |
| #define CIFSROOT_RETRY_MAX 5 |
| |
| static int __init mount_cifs_root(void) |
| { |
| char *root_dev, *root_data; |
| unsigned int timeout; |
| int try, err; |
| |
| err = cifs_root_data(&root_dev, &root_data); |
| if (err != 0) |
| return 0; |
| |
| timeout = CIFSROOT_TIMEOUT_MIN; |
| for (try = 1; ; try++) { |
| err = do_mount_root(root_dev, "cifs", root_mountflags, |
| root_data); |
| if (err == 0) |
| return 1; |
| if (try > CIFSROOT_RETRY_MAX) |
| break; |
| |
| ssleep(timeout); |
| timeout <<= 1; |
| if (timeout > CIFSROOT_TIMEOUT_MAX) |
| timeout = CIFSROOT_TIMEOUT_MAX; |
| } |
| return 0; |
| } |
| #endif |
| |
| 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(void) |
| { |
| 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, root_fs_names); |
| |
| 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; |
| } |
| |
| void __init mount_root(void) |
| { |
| #ifdef CONFIG_ROOT_NFS |
| if (ROOT_DEV == Root_NFS) { |
| if (!mount_nfs_root()) |
| printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n"); |
| return; |
| } |
| #endif |
| #ifdef CONFIG_CIFS_ROOT |
| if (ROOT_DEV == Root_CIFS) { |
| if (!mount_cifs_root()) |
| printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n"); |
| return; |
| } |
| #endif |
| if (ROOT_DEV == 0 && root_device_name && root_fs_names) { |
| if (mount_nodev_root() == 0) |
| return; |
| } |
| #ifdef CONFIG_BLOCK |
| { |
| int err = create_dev("/dev/root", ROOT_DEV); |
| |
| if (err < 0) |
| pr_emerg("Failed to create /dev/root: %d\n", err); |
| mount_block_root("/dev/root", root_mountflags); |
| } |
| #endif |
| } |
| |
| /* |
| * 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_device_name = saved_root_name; |
| if (!strncmp(root_device_name, "mtd", 3) || |
| !strncmp(root_device_name, "ubi", 3)) { |
| mount_block_root(root_device_name, root_mountflags); |
| goto out; |
| } |
| ROOT_DEV = name_to_dev_t(root_device_name); |
| if (strncmp(root_device_name, "/dev/", 5) == 0) |
| root_device_name += 5; |
| } |
| |
| if (initrd_load()) |
| goto out; |
| |
| /* wait for any asynchronous scanning to complete */ |
| if ((ROOT_DEV == 0) && root_wait) { |
| printk(KERN_INFO "Waiting for root device %s...\n", |
| saved_root_name); |
| while (driver_probe_done() != 0 || |
| (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) |
| msleep(5); |
| async_synchronize_full(); |
| } |
| |
| mount_root(); |
| out: |
| devtmpfs_mount(); |
| init_mount(".", "/", NULL, MS_MOVE, NULL); |
| init_chroot("."); |
| } |
| |
| 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_litter_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; |
| } |
| } |