linux/fs/adfs/super.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/fs/adfs/super.c
   4 *
   5 *  Copyright (C) 1997-1999 Russell King
   6 */
   7#include <linux/module.h>
   8#include <linux/init.h>
   9#include <linux/parser.h>
  10#include <linux/mount.h>
  11#include <linux/seq_file.h>
  12#include <linux/slab.h>
  13#include <linux/statfs.h>
  14#include <linux/user_namespace.h>
  15#include <linux/blkdev.h>
  16#include "adfs.h"
  17#include "dir_f.h"
  18#include "dir_fplus.h"
  19
  20#define ADFS_SB_FLAGS SB_NOATIME
  21
  22#define ADFS_DEFAULT_OWNER_MASK S_IRWXU
  23#define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
  24
  25void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
  26{
  27        struct va_format vaf;
  28        va_list args;
  29
  30        va_start(args, fmt);
  31        vaf.fmt = fmt;
  32        vaf.va = &args;
  33
  34        printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %pV\n",
  35                sb->s_id, function ? ": " : "",
  36                function ? function : "", &vaf);
  37
  38        va_end(args);
  39}
  40
  41void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...)
  42{
  43        struct va_format vaf;
  44        va_list args;
  45
  46        va_start(args, fmt);
  47        vaf.fmt = fmt;
  48        vaf.va = &args;
  49        printk("%sADFS-fs (%s): %pV\n", pfx, sb->s_id, &vaf);
  50        va_end(args);
  51}
  52
  53static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  54{
  55        unsigned int max_idlen;
  56        int i;
  57
  58        /* sector size must be 256, 512 or 1024 bytes */
  59        if (dr->log2secsize != 8 &&
  60            dr->log2secsize != 9 &&
  61            dr->log2secsize != 10)
  62                return 1;
  63
  64        /* idlen must be at least log2secsize + 3 */
  65        if (dr->idlen < dr->log2secsize + 3)
  66                return 1;
  67
  68        /* we cannot have such a large disc that we
  69         * are unable to represent sector offsets in
  70         * 32 bits.  This works out at 2.0 TB.
  71         */
  72        if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  73                return 1;
  74
  75        /*
  76         * Maximum idlen is limited to 16 bits for new directories by
  77         * the three-byte storage of an indirect disc address.  For
  78         * big directories, idlen must be no greater than 19 v2 [1.0]
  79         */
  80        max_idlen = dr->format_version ? 19 : 16;
  81        if (dr->idlen > max_idlen)
  82                return 1;
  83
  84        /* reserved bytes should be zero */
  85        for (i = 0; i < sizeof(dr->unused52); i++)
  86                if (dr->unused52[i] != 0)
  87                        return 1;
  88
  89        return 0;
  90}
  91
  92static void adfs_put_super(struct super_block *sb)
  93{
  94        struct adfs_sb_info *asb = ADFS_SB(sb);
  95
  96        adfs_free_map(sb);
  97        kfree_rcu(asb, rcu);
  98}
  99
 100static int adfs_show_options(struct seq_file *seq, struct dentry *root)
 101{
 102        struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
 103
 104        if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
 105                seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
 106        if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
 107                seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
 108        if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 109                seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 110        if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 111                seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 112        if (asb->s_ftsuffix != 0)
 113                seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
 114
 115        return 0;
 116}
 117
 118enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
 119
 120static const match_table_t tokens = {
 121        {Opt_uid, "uid=%u"},
 122        {Opt_gid, "gid=%u"},
 123        {Opt_ownmask, "ownmask=%o"},
 124        {Opt_othmask, "othmask=%o"},
 125        {Opt_ftsuffix, "ftsuffix=%u"},
 126        {Opt_err, NULL}
 127};
 128
 129static int parse_options(struct super_block *sb, struct adfs_sb_info *asb,
 130                         char *options)
 131{
 132        char *p;
 133        int option;
 134
 135        if (!options)
 136                return 0;
 137
 138        while ((p = strsep(&options, ",")) != NULL) {
 139                substring_t args[MAX_OPT_ARGS];
 140                int token;
 141                if (!*p)
 142                        continue;
 143
 144                token = match_token(p, tokens, args);
 145                switch (token) {
 146                case Opt_uid:
 147                        if (match_int(args, &option))
 148                                return -EINVAL;
 149                        asb->s_uid = make_kuid(current_user_ns(), option);
 150                        if (!uid_valid(asb->s_uid))
 151                                return -EINVAL;
 152                        break;
 153                case Opt_gid:
 154                        if (match_int(args, &option))
 155                                return -EINVAL;
 156                        asb->s_gid = make_kgid(current_user_ns(), option);
 157                        if (!gid_valid(asb->s_gid))
 158                                return -EINVAL;
 159                        break;
 160                case Opt_ownmask:
 161                        if (match_octal(args, &option))
 162                                return -EINVAL;
 163                        asb->s_owner_mask = option;
 164                        break;
 165                case Opt_othmask:
 166                        if (match_octal(args, &option))
 167                                return -EINVAL;
 168                        asb->s_other_mask = option;
 169                        break;
 170                case Opt_ftsuffix:
 171                        if (match_int(args, &option))
 172                                return -EINVAL;
 173                        asb->s_ftsuffix = option;
 174                        break;
 175                default:
 176                        adfs_msg(sb, KERN_ERR,
 177                                 "unrecognised mount option \"%s\" or missing value",
 178                                 p);
 179                        return -EINVAL;
 180                }
 181        }
 182        return 0;
 183}
 184
 185static int adfs_remount(struct super_block *sb, int *flags, char *data)
 186{
 187        struct adfs_sb_info temp_asb;
 188        int ret;
 189
 190        sync_filesystem(sb);
 191        *flags |= ADFS_SB_FLAGS;
 192
 193        temp_asb = *ADFS_SB(sb);
 194        ret = parse_options(sb, &temp_asb, data);
 195        if (ret == 0)
 196                *ADFS_SB(sb) = temp_asb;
 197
 198        return ret;
 199}
 200
 201static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 202{
 203        struct super_block *sb = dentry->d_sb;
 204        struct adfs_sb_info *sbi = ADFS_SB(sb);
 205        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 206
 207        adfs_map_statfs(sb, buf);
 208
 209        buf->f_type    = ADFS_SUPER_MAGIC;
 210        buf->f_namelen = sbi->s_namelen;
 211        buf->f_bsize   = sb->s_blocksize;
 212        buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 213        buf->f_fsid    = u64_to_fsid(id);
 214
 215        return 0;
 216}
 217
 218static struct kmem_cache *adfs_inode_cachep;
 219
 220static struct inode *adfs_alloc_inode(struct super_block *sb)
 221{
 222        struct adfs_inode_info *ei;
 223        ei = alloc_inode_sb(sb, adfs_inode_cachep, GFP_KERNEL);
 224        if (!ei)
 225                return NULL;
 226        return &ei->vfs_inode;
 227}
 228
 229static void adfs_free_inode(struct inode *inode)
 230{
 231        kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 232}
 233
 234static int adfs_drop_inode(struct inode *inode)
 235{
 236        /* always drop inodes if we are read-only */
 237        return !IS_ENABLED(CONFIG_ADFS_FS_RW) || IS_RDONLY(inode);
 238}
 239
 240static void init_once(void *foo)
 241{
 242        struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 243
 244        inode_init_once(&ei->vfs_inode);
 245}
 246
 247static int __init init_inodecache(void)
 248{
 249        adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 250                                             sizeof(struct adfs_inode_info),
 251                                             0, (SLAB_RECLAIM_ACCOUNT|
 252                                                SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 253                                             init_once);
 254        if (adfs_inode_cachep == NULL)
 255                return -ENOMEM;
 256        return 0;
 257}
 258
 259static void destroy_inodecache(void)
 260{
 261        /*
 262         * Make sure all delayed rcu free inodes are flushed before we
 263         * destroy cache.
 264         */
 265        rcu_barrier();
 266        kmem_cache_destroy(adfs_inode_cachep);
 267}
 268
 269static const struct super_operations adfs_sops = {
 270        .alloc_inode    = adfs_alloc_inode,
 271        .free_inode     = adfs_free_inode,
 272        .drop_inode     = adfs_drop_inode,
 273        .write_inode    = adfs_write_inode,
 274        .put_super      = adfs_put_super,
 275        .statfs         = adfs_statfs,
 276        .remount_fs     = adfs_remount,
 277        .show_options   = adfs_show_options,
 278};
 279
 280static int adfs_probe(struct super_block *sb, unsigned int offset, int silent,
 281                      int (*validate)(struct super_block *sb,
 282                                      struct buffer_head *bh,
 283                                      struct adfs_discrecord **bhp))
 284{
 285        struct adfs_sb_info *asb = ADFS_SB(sb);
 286        struct adfs_discrecord *dr;
 287        struct buffer_head *bh;
 288        unsigned int blocksize = BLOCK_SIZE;
 289        int ret, try;
 290
 291        for (try = 0; try < 2; try++) {
 292                /* try to set the requested block size */
 293                if (sb->s_blocksize != blocksize &&
 294                    !sb_set_blocksize(sb, blocksize)) {
 295                        if (!silent)
 296                                adfs_msg(sb, KERN_ERR,
 297                                         "error: unsupported blocksize");
 298                        return -EINVAL;
 299                }
 300
 301                /* read the buffer */
 302                bh = sb_bread(sb, offset >> sb->s_blocksize_bits);
 303                if (!bh) {
 304                        adfs_msg(sb, KERN_ERR,
 305                                 "error: unable to read block %u, try %d",
 306                                 offset >> sb->s_blocksize_bits, try);
 307                        return -EIO;
 308                }
 309
 310                /* validate it */
 311                ret = validate(sb, bh, &dr);
 312                if (ret) {
 313                        brelse(bh);
 314                        return ret;
 315                }
 316
 317                /* does the block size match the filesystem block size? */
 318                blocksize = 1 << dr->log2secsize;
 319                if (sb->s_blocksize == blocksize) {
 320                        asb->s_map = adfs_read_map(sb, dr);
 321                        brelse(bh);
 322                        return PTR_ERR_OR_ZERO(asb->s_map);
 323                }
 324
 325                brelse(bh);
 326        }
 327
 328        return -EIO;
 329}
 330
 331static int adfs_validate_bblk(struct super_block *sb, struct buffer_head *bh,
 332                              struct adfs_discrecord **drp)
 333{
 334        struct adfs_discrecord *dr;
 335        unsigned char *b_data;
 336
 337        b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 338        if (adfs_checkbblk(b_data))
 339                return -EILSEQ;
 340
 341        /* Do some sanity checks on the ADFS disc record */
 342        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 343        if (adfs_checkdiscrecord(dr))
 344                return -EILSEQ;
 345
 346        *drp = dr;
 347        return 0;
 348}
 349
 350static int adfs_validate_dr0(struct super_block *sb, struct buffer_head *bh,
 351                              struct adfs_discrecord **drp)
 352{
 353        struct adfs_discrecord *dr;
 354
 355        /* Do some sanity checks on the ADFS disc record */
 356        dr = (struct adfs_discrecord *)(bh->b_data + 4);
 357        if (adfs_checkdiscrecord(dr) || dr->nzones_high || dr->nzones != 1)
 358                return -EILSEQ;
 359
 360        *drp = dr;
 361        return 0;
 362}
 363
 364static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 365{
 366        struct adfs_discrecord *dr;
 367        struct object_info root_obj;
 368        struct adfs_sb_info *asb;
 369        struct inode *root;
 370        int ret = -EINVAL;
 371
 372        sb->s_flags |= ADFS_SB_FLAGS;
 373
 374        asb = kzalloc(sizeof(*asb), GFP_KERNEL);
 375        if (!asb)
 376                return -ENOMEM;
 377
 378        sb->s_fs_info = asb;
 379        sb->s_magic = ADFS_SUPER_MAGIC;
 380        sb->s_time_gran = 10000000;
 381
 382        /* set default options */
 383        asb->s_uid = GLOBAL_ROOT_UID;
 384        asb->s_gid = GLOBAL_ROOT_GID;
 385        asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 386        asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 387        asb->s_ftsuffix = 0;
 388
 389        if (parse_options(sb, asb, data))
 390                goto error;
 391
 392        /* Try to probe the filesystem boot block */
 393        ret = adfs_probe(sb, ADFS_DISCRECORD, 1, adfs_validate_bblk);
 394        if (ret == -EILSEQ)
 395                ret = adfs_probe(sb, 0, silent, adfs_validate_dr0);
 396        if (ret == -EILSEQ) {
 397                if (!silent)
 398                        adfs_msg(sb, KERN_ERR,
 399                                 "error: can't find an ADFS filesystem on dev %s.",
 400                                 sb->s_id);
 401                ret = -EINVAL;
 402        }
 403        if (ret)
 404                goto error;
 405
 406        /* set up enough so that we can read an inode */
 407        sb->s_op = &adfs_sops;
 408
 409        dr = adfs_map_discrecord(asb->s_map);
 410
 411        root_obj.parent_id = root_obj.indaddr = le32_to_cpu(dr->root);
 412        root_obj.name_len  = 0;
 413        /* Set root object date as 01 Jan 1987 00:00:00 */
 414        root_obj.loadaddr  = 0xfff0003f;
 415        root_obj.execaddr  = 0xec22c000;
 416        root_obj.size      = ADFS_NEWDIR_SIZE;
 417        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 418                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 419
 420        /*
 421         * If this is a F+ disk with variable length directories,
 422         * get the root_size from the disc record.
 423         */
 424        if (dr->format_version) {
 425                root_obj.size = le32_to_cpu(dr->root_size);
 426                asb->s_dir     = &adfs_fplus_dir_ops;
 427                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 428        } else {
 429                asb->s_dir     = &adfs_f_dir_ops;
 430                asb->s_namelen = ADFS_F_NAME_LEN;
 431        }
 432        /*
 433         * ,xyz hex filetype suffix may be added by driver
 434         * to files that have valid RISC OS filetype
 435         */
 436        if (asb->s_ftsuffix)
 437                asb->s_namelen += 4;
 438
 439        sb->s_d_op = &adfs_dentry_operations;
 440        root = adfs_iget(sb, &root_obj);
 441        sb->s_root = d_make_root(root);
 442        if (!sb->s_root) {
 443                adfs_free_map(sb);
 444                adfs_error(sb, "get root inode failed\n");
 445                ret = -EIO;
 446                goto error;
 447        }
 448        return 0;
 449
 450error:
 451        sb->s_fs_info = NULL;
 452        kfree(asb);
 453        return ret;
 454}
 455
 456static struct dentry *adfs_mount(struct file_system_type *fs_type,
 457        int flags, const char *dev_name, void *data)
 458{
 459        return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
 460}
 461
 462static struct file_system_type adfs_fs_type = {
 463        .owner          = THIS_MODULE,
 464        .name           = "adfs",
 465        .mount          = adfs_mount,
 466        .kill_sb        = kill_block_super,
 467        .fs_flags       = FS_REQUIRES_DEV,
 468};
 469MODULE_ALIAS_FS("adfs");
 470
 471static int __init init_adfs_fs(void)
 472{
 473        int err = init_inodecache();
 474        if (err)
 475                goto out1;
 476        err = register_filesystem(&adfs_fs_type);
 477        if (err)
 478                goto out;
 479        return 0;
 480out:
 481        destroy_inodecache();
 482out1:
 483        return err;
 484}
 485
 486static void __exit exit_adfs_fs(void)
 487{
 488        unregister_filesystem(&adfs_fs_type);
 489        destroy_inodecache();
 490}
 491
 492module_init(init_adfs_fs)
 493module_exit(exit_adfs_fs)
 494MODULE_LICENSE("GPL");
 495