diff options
Diffstat (limited to 'kernel/init/do_mounts.c')
| -rw-r--r-- | kernel/init/do_mounts.c | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/kernel/init/do_mounts.c b/kernel/init/do_mounts.c new file mode 100644 index 000000000..a95bbdb2a --- /dev/null +++ b/kernel/init/do_mounts.c @@ -0,0 +1,643 @@ +/* + * Many of the syscalls used in this file expect some of the arguments + * to be __user pointers not __kernel pointers. To limit the sparse + * noise, turn off sparse checking for this file. + */ +#ifdef __CHECKER__ +#undef __CHECKER__ +#warning "Sparse checking disabled for this file" +#endif + +#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/genhd.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 "do_mounts.h" + +int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ + +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) +{ + rd_doload = simple_strtol(str,NULL,0) & 3; + 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) +{ + const struct uuidcmp *cmp = data; + struct hd_struct *part = dev_to_part(dev); + + if (!part->info) + goto no_match; + + if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) + goto no_match; + + return 1; +no_match: + return 0; +} + + +/** + * 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) +{ + dev_t res = 0; + struct uuidcmp cmp; + struct device *dev = NULL; + struct gendisk *disk; + struct hd_struct *part; + int offset = 0; + bool clear_root_wait = false; + 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) { + clear_root_wait = true; + goto done; + } + cmp.len = slash - uuid_str; + } else { + cmp.len = strlen(uuid_str); + } + + if (!cmp.len) { + clear_root_wait = true; + goto done; + } + + dev = class_find_device(&block_class, NULL, &cmp, + &match_dev_by_uuid); + if (!dev) + goto done; + + res = dev->devt; + + /* Attempt to find the partition by offset. */ + if (!offset) + goto no_offset; + + res = 0; + disk = part_to_disk(dev_to_part(dev)); + part = disk_get_part(disk, dev_to_part(dev)->partno + offset); + if (part) { + res = part_devt(part); + put_device(part_to_dev(part)); + } + +no_offset: + put_device(dev); +done: + if (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 res; +} +#endif + +/* + * 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. + * + * 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) +{ + char s[32]; + char *p; + dev_t res = 0; + int part; + +#ifdef CONFIG_BLOCK + if (strncmp(name, "PARTUUID=", 9) == 0) { + name += 9; + res = devt_from_partuuid(name); + if (!res) + goto fail; + goto done; + } +#endif + + if (strncmp(name, "/dev/", 5) != 0) { + unsigned maj, min, offset; + char dummy; + + if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) || + (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) { + res = MKDEV(maj, min); + if (maj != MAJOR(res) || min != MINOR(res)) + goto fail; + } else { + res = new_decode_dev(simple_strtoul(name, &p, 16)); + if (*p) + goto fail; + } + goto done; + } + + name += 5; + res = Root_NFS; + if (strcmp(name, "nfs") == 0) + goto done; + res = Root_RAM0; + if (strcmp(name, "ram") == 0) + goto done; + + if (strlen(name) > 31) + goto fail; + strcpy(s, name); + for (p = s; *p; p++) + if (*p == '/') + *p = '!'; + res = blk_lookup_devt(s, 0); + if (res) + goto done; + + /* + * try non-existent, but valid partition, which may only exist + * after revalidating the disk, like partitioned md devices + */ + while (p > s && isdigit(p[-1])) + p--; + if (p == s || !*p || *p == '0') + goto fail; + + /* try disk name without <part number> */ + part = simple_strtoul(p, NULL, 10); + *p = '\0'; + res = blk_lookup_devt(s, part); + if (res) + goto done; + + /* try disk name without p<part number> */ + if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') + goto fail; + p[-1] = '\0'; + res = blk_lookup_devt(s, part); + if (res) + goto done; + +fail: + return 0; +done: + return res; +} +EXPORT_SYMBOL_GPL(name_to_dev_t); + +static int __init root_dev_setup(char *line) +{ + strlcpy(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); + +static void __init get_fs_names(char *page) +{ + char *s = page; + + if (root_fs_names) { + strcpy(page, root_fs_names); + while (*s++) { + if (s[-1] == ',') + s[-1] = '\0'; + } + } else { + int len = get_filesystem_list(page); + char *p, *next; + + page[len] = '\0'; + for (p = page-1; p; p = next) { + next = strchr(++p, '\n'); + if (*p++ != '\t') + continue; + while ((*s++ = *p++) != '\n') + ; + s[-1] = '\0'; + } + } + *s = '\0'; +} + +static int __init do_mount_root(char *name, char *fs, int flags, void *data) +{ + struct super_block *s; + int err = sys_mount(name, "/root", fs, flags, data); + if (err) + return err; + + sys_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, + s->s_flags & MS_RDONLY ? " readonly" : "", + MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); + return 0; +} + +void __init mount_block_root(char *name, int flags) +{ + struct page *page = alloc_page(GFP_KERNEL | + __GFP_NOTRACK_FALSE_POSITIVE); + char *fs_names = page_address(page); + char *p; +#ifdef CONFIG_BLOCK + char b[BDEVNAME_SIZE]; +#else + const char *b = name; +#endif + + get_fs_names(fs_names); +retry: + for (p = fs_names; *p; p += strlen(p)+1) { + int 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 + */ +#ifdef CONFIG_BLOCK + __bdevname(ROOT_DEV, b); +#endif + 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(); +#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT + printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " + "explicit textual name for \"root=\" boot option.\n"); +#endif + panic("VFS: Unable to mount root fs on %s", b); + } + if (!(flags & MS_RDONLY)) { + flags |= MS_RDONLY; + goto retry; + } + + printk("List of all partitions:\n"); + printk_all_partitions(); + printk("No filesystem could mount root, tried: "); + for (p = fs_names; *p; p += strlen(p)+1) + printk(" %s", p); + printk("\n"); +#ifdef CONFIG_BLOCK + __bdevname(ROOT_DEV, b); +#endif + 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 + +#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) +void __init change_floppy(char *fmt, ...) +{ + struct termios termios; + char buf[80]; + char c; + int fd; + va_list args; + va_start(args, fmt); + vsprintf(buf, fmt, args); + va_end(args); + fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); + if (fd >= 0) { + sys_ioctl(fd, FDEJECT, 0); + sys_close(fd); + } + printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); + fd = sys_open("/dev/console", O_RDWR, 0); + if (fd >= 0) { + sys_ioctl(fd, TCGETS, (long)&termios); + termios.c_lflag &= ~ICANON; + sys_ioctl(fd, TCSETSF, (long)&termios); + sys_read(fd, &c, 1); + termios.c_lflag |= ICANON; + sys_ioctl(fd, TCSETSF, (long)&termios); + sys_close(fd); + } +} +#endif + +void __init mount_root(void) +{ +#ifdef CONFIG_ROOT_NFS + if (ROOT_DEV == Root_NFS) { + if (mount_nfs_root()) + return; + + printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); + ROOT_DEV = Root_FD0; + } +#endif +#ifdef CONFIG_BLK_DEV_FD + if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { + /* rd_doload is 2 for a dual initrd/ramload setup */ + if (rd_doload==2) { + if (rd_load_disk(1)) { + ROOT_DEV = Root_RAM1; + root_device_name = NULL; + } + } else + change_floppy("root floppy"); + } +#endif +#ifdef CONFIG_BLOCK + create_dev("/dev/root", ROOT_DEV); + mount_block_root("/dev/root", root_mountflags); +#endif +} + +/* + * Prepare the namespace - decide what/where to mount, load ramdisks, etc. + */ +void __init prepare_namespace(void) +{ + int is_floppy; + + 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(100); + async_synchronize_full(); + } + + is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; + + if (is_floppy && rd_doload && rd_load_disk(0)) + ROOT_DEV = Root_RAM0; + + mount_root(); +out: + devtmpfs_mount("dev"); + sys_mount(".", "/", NULL, MS_MOVE, NULL); + sys_chroot("."); +} + +static bool is_tmpfs; +static struct dentry *rootfs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + static unsigned long once; + void *fill = ramfs_fill_super; + + if (test_and_set_bit(0, &once)) + return ERR_PTR(-ENODEV); + + if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) + fill = shmem_fill_super; + + return mount_nodev(fs_type, flags, data, fill); +} + +static struct file_system_type rootfs_fs_type = { + .name = "rootfs", + .mount = rootfs_mount, + .kill_sb = kill_litter_super, +}; + +int __init init_rootfs(void) +{ + int err = register_filesystem(&rootfs_fs_type); + + if (err) + return err; + + if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && + (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { + err = shmem_init(); + is_tmpfs = true; + } else { + err = init_ramfs_fs(); + } + + if (err) + unregister_filesystem(&rootfs_fs_type); + + return err; +} |