diff options
Diffstat (limited to 'grub-core/fs/romfs.c')
| -rw-r--r-- | grub-core/fs/romfs.c | 484 |
1 files changed, 484 insertions, 0 deletions
diff --git a/grub-core/fs/romfs.c b/grub-core/fs/romfs.c new file mode 100644 index 0000000..d97b8fb --- /dev/null +++ b/grub-core/fs/romfs.c @@ -0,0 +1,484 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2010 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/file.h> +#include <grub/types.h> +#include <grub/dl.h> +#include <grub/mm.h> +#include <grub/disk.h> +#include <grub/fs.h> +#include <grub/fshelp.h> + +GRUB_MOD_LICENSE ("GPLv3+"); + +struct grub_romfs_superblock +{ + char magic[8]; +#define GRUB_ROMFS_MAGIC "-rom1fs-" + grub_uint32_t total_size; + grub_uint32_t chksum; + char label[0]; +}; + +struct grub_romfs_file_header +{ + grub_uint32_t next_file; + grub_uint32_t spec; + grub_uint32_t size; + grub_uint32_t chksum; + char name[0]; +}; + +struct grub_romfs_data +{ + grub_disk_addr_t first_file; + grub_disk_t disk; +}; + +struct grub_fshelp_node +{ + grub_disk_addr_t addr; + struct grub_romfs_data *data; + grub_disk_addr_t data_addr; + /* Not filled for root. */ + struct grub_romfs_file_header file; +}; + +#define GRUB_ROMFS_ALIGN 16 +#define GRUB_ROMFS_TYPE_MASK 7 +#define GRUB_ROMFS_TYPE_HARDLINK 0 +#define GRUB_ROMFS_TYPE_DIRECTORY 1 +#define GRUB_ROMFS_TYPE_REGULAR 2 +#define GRUB_ROMFS_TYPE_SYMLINK 3 + +static grub_err_t +do_checksum (void *in, grub_size_t insize) +{ + grub_uint32_t *a = in; + grub_size_t sz = insize / 4; + grub_uint32_t *b = a + sz; + grub_uint32_t csum = 0; + + while (a < b) + csum += grub_be_to_cpu32 (*a++); + if (csum) + return grub_error (GRUB_ERR_BAD_FS, "invalid checksum"); + return GRUB_ERR_NONE; +} + +static struct grub_romfs_data * +grub_romfs_mount (grub_device_t dev) +{ + union { + struct grub_romfs_superblock sb; + char d[512]; + } sb; + grub_err_t err; + char *ptr; + grub_disk_addr_t sec = 0; + struct grub_romfs_data *data; + if (!dev->disk) + { + grub_error (GRUB_ERR_BAD_FS, "not a disk"); + return NULL; + } + err = grub_disk_read (dev->disk, 0, 0, sizeof (sb), &sb); + if (err == GRUB_ERR_OUT_OF_RANGE) + err = grub_errno = GRUB_ERR_BAD_FS; + if (err) + return NULL; + if (grub_be_to_cpu32 (sb.sb.total_size) < sizeof (sb)) + { + grub_error (GRUB_ERR_BAD_FS, "too short filesystem"); + return NULL; + } + if (grub_memcmp (sb.sb.magic, GRUB_ROMFS_MAGIC, + sizeof (sb.sb.magic)) != 0) + { + grub_error (GRUB_ERR_BAD_FS, "not romfs"); + return NULL; + } + err = do_checksum (&sb, sizeof (sb) < grub_be_to_cpu32 (sb.sb.total_size) ? + sizeof (sb) : grub_be_to_cpu32 (sb.sb.total_size)); + if (err) + { + grub_error (GRUB_ERR_BAD_FS, "checksum incorrect"); + return NULL; + } + for (ptr = sb.sb.label; (void *) ptr < (void *) (&sb + 1) + && ptr - sb.d < (grub_ssize_t) grub_be_to_cpu32 (sb.sb.total_size); ptr++) + if (!*ptr) + break; + while ((void *) ptr == &sb + 1) + { + sec++; + err = grub_disk_read (dev->disk, sec, 0, sizeof (sb), &sb); + if (err == GRUB_ERR_OUT_OF_RANGE) + err = grub_errno = GRUB_ERR_BAD_FS; + if (err) + return NULL; + for (ptr = sb.d; (void *) ptr < (void *) (&sb + 1) + && (ptr - sb.d + (sec << GRUB_DISK_SECTOR_BITS) + < grub_be_to_cpu32 (sb.sb.total_size)); + ptr++) + if (!*ptr) + break; + } + data = grub_malloc (sizeof (*data)); + if (!data) + return NULL; + data->first_file = ALIGN_UP (ptr + 1 - sb.d, GRUB_ROMFS_ALIGN) + + (sec << GRUB_DISK_SECTOR_BITS); + data->disk = dev->disk; + return data; +} + +static char * +grub_romfs_read_symlink (grub_fshelp_node_t node) +{ + char *ret; + grub_err_t err; + ret = grub_malloc (grub_be_to_cpu32 (node->file.size) + 1); + if (!ret) + return NULL; + err = grub_disk_read (node->data->disk, + (node->data_addr) >> GRUB_DISK_SECTOR_BITS, + (node->data_addr) & (GRUB_DISK_SECTOR_SIZE - 1), + grub_be_to_cpu32 (node->file.size), ret); + if (err) + { + grub_free (ret); + return NULL; + } + ret[grub_be_to_cpu32 (node->file.size)] = 0; + return ret; +} + +static int +grub_romfs_iterate_dir (grub_fshelp_node_t dir, + grub_fshelp_iterate_dir_hook_t hook, void *hook_data) +{ + grub_disk_addr_t caddr; + struct grub_romfs_file_header hdr; + unsigned nptr; + unsigned i, j; + grub_size_t a = 0; + grub_properly_aligned_t *name = NULL; + + for (caddr = dir->data_addr; caddr; + caddr = grub_be_to_cpu32 (hdr.next_file) & ~(GRUB_ROMFS_ALIGN - 1)) + { + grub_disk_addr_t naddr = caddr + sizeof (hdr); + grub_uint32_t csum = 0; + enum grub_fshelp_filetype filetype = GRUB_FSHELP_UNKNOWN; + struct grub_fshelp_node *node = NULL; + grub_err_t err; + + err = grub_disk_read (dir->data->disk, caddr >> GRUB_DISK_SECTOR_BITS, + caddr & (GRUB_DISK_SECTOR_SIZE - 1), + sizeof (hdr), &hdr); + if (err) + { + grub_free (name); + return 1; + } + for (nptr = 0; ; nptr++, naddr += 16) + { + if (a <= nptr) + { + grub_properly_aligned_t *on; + a = 2 * (nptr + 1); + on = name; + name = grub_realloc (name, a * 16); + if (!name) + { + grub_free (on); + return 1; + } + } + COMPILE_TIME_ASSERT (16 % sizeof (name[0]) == 0); + err = grub_disk_read (dir->data->disk, naddr >> GRUB_DISK_SECTOR_BITS, + naddr & (GRUB_DISK_SECTOR_SIZE - 1), + 16, name + (16 / sizeof (name[0])) * nptr); + if (err) + return 1; + for (j = 0; j < 16; j++) + if (!((char *) name)[16 * nptr + j]) + break; + if (j != 16) + break; + } + for (i = 0; i < sizeof (hdr) / sizeof (grub_uint32_t); i++) + csum += grub_be_to_cpu32 (((grub_uint32_t *) &hdr)[i]); + for (i = 0; i < (nptr + 1) * 4; i++) + csum += grub_be_to_cpu32 (((grub_uint32_t *) name)[i]); + if (csum != 0) + { + grub_error (GRUB_ERR_BAD_FS, "invalid checksum"); + grub_free (name); + return 1; + } + node = grub_malloc (sizeof (*node)); + if (!node) + return 1; + node->addr = caddr; + node->data_addr = caddr + (nptr + 1) * 16 + sizeof (hdr); + node->data = dir->data; + node->file = hdr; + switch (grub_be_to_cpu32 (hdr.next_file) & GRUB_ROMFS_TYPE_MASK) + { + case GRUB_ROMFS_TYPE_REGULAR: + filetype = GRUB_FSHELP_REG; + break; + case GRUB_ROMFS_TYPE_SYMLINK: + filetype = GRUB_FSHELP_SYMLINK; + break; + case GRUB_ROMFS_TYPE_DIRECTORY: + node->data_addr = grub_be_to_cpu32 (hdr.spec); + filetype = GRUB_FSHELP_DIR; + break; + case GRUB_ROMFS_TYPE_HARDLINK: + { + grub_disk_addr_t laddr; + node->addr = laddr = grub_be_to_cpu32 (hdr.spec); + err = grub_disk_read (dir->data->disk, + laddr >> GRUB_DISK_SECTOR_BITS, + laddr & (GRUB_DISK_SECTOR_SIZE - 1), + sizeof (node->file), &node->file); + if (err) + return 1; + if ((grub_be_to_cpu32 (node->file.next_file) & GRUB_ROMFS_TYPE_MASK) + == GRUB_ROMFS_TYPE_REGULAR + || (grub_be_to_cpu32 (node->file.next_file) + & GRUB_ROMFS_TYPE_MASK) == GRUB_ROMFS_TYPE_SYMLINK) + { + laddr += sizeof (hdr); + while (1) + { + char buf[16]; + err = grub_disk_read (dir->data->disk, + laddr >> GRUB_DISK_SECTOR_BITS, + laddr & (GRUB_DISK_SECTOR_SIZE - 1), + 16, buf); + if (err) + return 1; + for (i = 0; i < 16; i++) + if (!buf[i]) + break; + if (i != 16) + break; + laddr += 16; + } + node->data_addr = laddr + 16; + } + if ((grub_be_to_cpu32 (node->file.next_file) + & GRUB_ROMFS_TYPE_MASK) == GRUB_ROMFS_TYPE_REGULAR) + filetype = GRUB_FSHELP_REG; + if ((grub_be_to_cpu32 (node->file.next_file) + & GRUB_ROMFS_TYPE_MASK) == GRUB_ROMFS_TYPE_SYMLINK) + filetype = GRUB_FSHELP_SYMLINK; + if ((grub_be_to_cpu32 (node->file.next_file) & GRUB_ROMFS_TYPE_MASK) + == GRUB_ROMFS_TYPE_DIRECTORY) + { + node->data_addr = grub_be_to_cpu32 (node->file.spec); + filetype = GRUB_FSHELP_DIR; + } + + break; + } + } + + if (hook ((char *) name, filetype, node, hook_data)) + { + grub_free (name); + return 1; + } + } + grub_free (name); + return 0; +} + +/* Context for grub_romfs_dir. */ +struct grub_romfs_dir_ctx +{ + grub_fs_dir_hook_t hook; + void *hook_data; +}; + +/* Helper for grub_romfs_dir. */ +static int +grub_romfs_dir_iter (const char *filename, enum grub_fshelp_filetype filetype, + grub_fshelp_node_t node, void *data) +{ + struct grub_romfs_dir_ctx *ctx = data; + struct grub_dirhook_info info; + + grub_memset (&info, 0, sizeof (info)); + + info.dir = ((filetype & GRUB_FSHELP_TYPE_MASK) == GRUB_FSHELP_DIR); + grub_free (node); + return ctx->hook (filename, &info, ctx->hook_data); +} + +static grub_err_t +grub_romfs_dir (grub_device_t device, const char *path, + grub_fs_dir_hook_t hook, void *hook_data) +{ + struct grub_romfs_dir_ctx ctx = { hook, hook_data }; + struct grub_romfs_data *data = 0; + struct grub_fshelp_node *fdiro = 0, start; + + data = grub_romfs_mount (device); + if (! data) + goto fail; + + start.addr = data->first_file; + start.data_addr = data->first_file; + start.data = data; + grub_fshelp_find_file (path, &start, &fdiro, grub_romfs_iterate_dir, + grub_romfs_read_symlink, GRUB_FSHELP_DIR); + if (grub_errno) + goto fail; + + grub_romfs_iterate_dir (fdiro, grub_romfs_dir_iter, &ctx); + + fail: + grub_free (data); + + return grub_errno; +} + +static grub_err_t +grub_romfs_open (struct grub_file *file, const char *name) +{ + struct grub_romfs_data *data = 0; + struct grub_fshelp_node *fdiro = 0, start; + + data = grub_romfs_mount (file->device); + if (! data) + goto fail; + + start.addr = data->first_file; + start.data_addr = data->first_file; + start.data = data; + + grub_fshelp_find_file (name, &start, &fdiro, grub_romfs_iterate_dir, + grub_romfs_read_symlink, GRUB_FSHELP_REG); + if (grub_errno) + goto fail; + + file->size = grub_be_to_cpu32 (fdiro->file.size); + file->data = fdiro; + return GRUB_ERR_NONE; + + fail: + grub_free (data); + + return grub_errno; +} + +static grub_ssize_t +grub_romfs_read (grub_file_t file, char *buf, grub_size_t len) +{ + struct grub_fshelp_node *data = file->data; + + /* XXX: The file is stored in as a single extent. */ + data->data->disk->read_hook = file->read_hook; + data->data->disk->read_hook_data = file->read_hook_data; + grub_disk_read (data->data->disk, + (data->data_addr + file->offset) >> GRUB_DISK_SECTOR_BITS, + (data->data_addr + file->offset) & (GRUB_DISK_SECTOR_SIZE - 1), + len, buf); + data->data->disk->read_hook = NULL; + + if (grub_errno) + return -1; + + return len; +} + +static grub_err_t +grub_romfs_close (grub_file_t file) +{ + struct grub_fshelp_node *data = file->data; + + grub_free (data->data); + grub_free (data); + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_romfs_label (grub_device_t device, char **label) +{ + struct grub_romfs_data *data; + grub_err_t err; + + *label = NULL; + + data = grub_romfs_mount (device); + if (!data) + return grub_errno; + *label = grub_malloc (data->first_file + 1 + - sizeof (struct grub_romfs_superblock)); + if (!*label) + { + grub_free (data); + return grub_errno; + } + err = grub_disk_read (device->disk, 0, sizeof (struct grub_romfs_superblock), + data->first_file + - sizeof (struct grub_romfs_superblock), + *label); + if (err) + { + grub_free (data); + grub_free (*label); + *label = NULL; + return err; + } + (*label)[data->first_file - sizeof (struct grub_romfs_superblock)] = 0; + grub_free (data); + return GRUB_ERR_NONE; +} + + +static struct grub_fs grub_romfs_fs = + { + .name = "romfs", + .fs_dir = grub_romfs_dir, + .fs_open = grub_romfs_open, + .fs_read = grub_romfs_read, + .fs_close = grub_romfs_close, + .fs_label = grub_romfs_label, +#ifdef GRUB_UTIL + .reserved_first_sector = 0, + .blocklist_install = 0, +#endif + .next = 0 + }; + +GRUB_MOD_INIT(romfs) +{ + grub_fs_register (&grub_romfs_fs); +} + +GRUB_MOD_FINI(romfs) +{ + grub_fs_unregister (&grub_romfs_fs); +} |