fs/openpromfs/inode.c

   1 /* inode.c: /proc/openprom handling routines
   2  *
   3  * Copyright (C) 1996-1999 Jakub Jelinek  (jakub@redhat.com)
   4  * Copyright (C) 1998      Eddie C. Dost  (ecd@skynet.be)
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/types.h>
   9 #include <linux/string.h>
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/slab.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/magic.h>
  15
  16 #include <asm/openprom.h>
  17 #include <asm/oplib.h>
  18 #include <asm/prom.h>
  19 #include <linux/uaccess.h>
  20
  21 static DEFINE_MUTEX(op_mutex);
  22
  23 #define OPENPROM_ROOT_INO       0
  24
  25 enum op_inode_type {
  26         op_inode_node,
  27         op_inode_prop,
  28 };
  29
  30 union op_inode_data {
  31         struct device_node      *node;
  32         struct property         *prop;
  33 };
  34
  35 struct op_inode_info {
  36         struct inode            vfs_inode;
  37         enum op_inode_type      type;
  38         union op_inode_data     u;
  39 };
  40
  41 static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
  42
  43 static inline struct op_inode_info *OP_I(struct inode *inode)
  44 {
  45         return container_of(inode, struct op_inode_info, vfs_inode);
  46 }
  47
  48 static int is_string(unsigned char *p, int len)
  49 {
  50         int i;
  51
  52         for (i = 0; i < len; i++) {
  53                 unsigned char val = p[i];
  54
  55                 if ((i && !val) ||
  56                     (val >= ' ' && val <= '~'))
  57                         continue;
  58
  59                 return 0;
  60         }
  61
  62         return 1;
  63 }
  64
  65 static int property_show(struct seq_file *f, void *v)
  66 {
  67         struct property *prop = f->private;
  68         void *pval;
  69         int len;
  70
  71         len = prop->length;
  72         pval = prop->value;
  73
  74         if (is_string(pval, len)) {
  75                 while (len > 0) {
  76                         int n = strlen(pval);
  77
  78                         seq_printf(f, "%s", (char *) pval);
  79
  80                         /* Skip over the NULL byte too.  */
  81                         pval += n + 1;
  82                         len -= n + 1;
  83
  84                         if (len > 0)
  85                                 seq_printf(f, " + ");
  86                 }
  87         } else {
  88                 if (len & 3) {
  89                         while (len) {
  90                                 len--;
  91                                 if (len)
  92                                         seq_printf(f, "%02x.",
  93                                                    *(unsigned char *) pval);
  94                                 else
  95                                         seq_printf(f, "%02x",
  96                                                    *(unsigned char *) pval);
  97                                 pval++;
  98                         }
  99                 } else {
 100                         while (len >= 4) {
 101                                 len -= 4;
 102
 103                                 if (len)
 104                                         seq_printf(f, "%08x.",
 105                                                    *(unsigned int *) pval);
 106                                 else
 107                                         seq_printf(f, "%08x",
 108                                                    *(unsigned int *) pval);
 109                                 pval += 4;
 110                         }
 111                 }
 112         }
 113         seq_printf(f, "\n");
 114
 115         return 0;
 116 }
 117
 118 static void *property_start(struct seq_file *f, loff_t *pos)
 119 {
 120         if (*pos == 0)
 121                 return pos;
 122         return NULL;
 123 }
 124
 125 static void *property_next(struct seq_file *f, void *v, loff_t *pos)
 126 {
 127         (*pos)++;
 128         return NULL;
 129 }
 130
 131 static void property_stop(struct seq_file *f, void *v)
 132 {
 133         /* Nothing to do */
 134 }
 135
 136 static const struct seq_operations property_op = {
 137         .start          = property_start,
 138         .next           = property_next,
 139         .stop           = property_stop,
 140         .show           = property_show
 141 };
 142
 143 static int property_open(struct inode *inode, struct file *file)
 144 {
 145         struct op_inode_info *oi = OP_I(inode);
 146         int ret;
 147
 148         BUG_ON(oi->type != op_inode_prop);
 149
 150         ret = seq_open(file, &property_op);
 151         if (!ret) {
 152                 struct seq_file *m = file->private_data;
 153                 m->private = oi->u.prop;
 154         }
 155         return ret;
 156 }
 157
 158 static const struct file_operations openpromfs_prop_ops = {
 159         .open           = property_open,
 160         .read           = seq_read,
 161         .llseek         = seq_lseek,
 162         .release        = seq_release,
 163 };
 164
 165 static int openpromfs_readdir(struct file *, struct dir_context *);
 166
 167 static const struct file_operations openprom_operations = {
 168         .read           = generic_read_dir,
 169         .iterate_shared = openpromfs_readdir,
 170         .llseek         = generic_file_llseek,
 171 };
 172
 173 static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);
 174
 175 static const struct inode_operations openprom_inode_operations = {
 176         .lookup         = openpromfs_lookup,
 177 };
 178
 179 static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 180 {
 181         struct op_inode_info *ent_oi, *oi = OP_I(dir);
 182         struct device_node *dp, *child;
 183         struct property *prop;
 184         enum op_inode_type ent_type;
 185         union op_inode_data ent_data;
 186         const char *name;
 187         struct inode *inode;
 188         unsigned int ino;
 189         int len;
 190
 191         BUG_ON(oi->type != op_inode_node);
 192
 193         dp = oi->u.node;
 194
 195         name = dentry->d_name.name;
 196         len = dentry->d_name.len;
 197
 198         mutex_lock(&op_mutex);
 199
 200         child = dp->child;
 201         while (child) {
 202                 int n = strlen(child->path_component_name);
 203
 204                 if (len == n &&
 205                     !strncmp(child->path_component_name, name, len)) {
 206                         ent_type = op_inode_node;
 207                         ent_data.node = child;
 208                         ino = child->unique_id;
 209                         goto found;
 210                 }
 211                 child = child->sibling;
 212         }
 213
 214         prop = dp->properties;
 215         while (prop) {
 216                 int n = strlen(prop->name);
 217
 218                 if (len == n && !strncmp(prop->name, name, len)) {
 219                         ent_type = op_inode_prop;
 220                         ent_data.prop = prop;
 221                         ino = prop->unique_id;
 222                         goto found;
 223                 }
 224
 225                 prop = prop->next;
 226         }
 227
 228         mutex_unlock(&op_mutex);
 229         return ERR_PTR(-ENOENT);
 230
 231 found:
 232         inode = openprom_iget(dir->i_sb, ino);
 233         mutex_unlock(&op_mutex);
 234         if (IS_ERR(inode))
 235                 return ERR_CAST(inode);
 236         ent_oi = OP_I(inode);
 237         ent_oi->type = ent_type;
 238         ent_oi->u = ent_data;
 239
 240         switch (ent_type) {
 241         case op_inode_node:
 242                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 243                 inode->i_op = &openprom_inode_operations;
 244                 inode->i_fop = &openprom_operations;
 245                 set_nlink(inode, 2);
 246                 break;
 247         case op_inode_prop:
 248                 if (!strcmp(dp->name, "options") && (len == 17) &&
 249                     !strncmp (name, "security-password", 17))
 250                         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 251                 else
 252                         inode->i_mode = S_IFREG | S_IRUGO;
 253                 inode->i_fop = &openpromfs_prop_ops;
 254                 set_nlink(inode, 1);
 255                 inode->i_size = ent_oi->u.prop->length;
 256                 break;
 257         }
 258
 259         d_add(dentry, inode);
 260         return NULL;
 261 }
 262
 263 static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
 264 {
 265         struct inode *inode = file_inode(file);
 266         struct op_inode_info *oi = OP_I(inode);
 267         struct device_node *dp = oi->u.node;
 268         struct device_node *child;
 269         struct property *prop;
 270         int i;
 271
 272         mutex_lock(&op_mutex);
 273
 274         if (ctx->pos == 0) {
 275                 if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
 276                         goto out;
 277                 ctx->pos = 1;
 278         }
 279         if (ctx->pos == 1) {
 280                 if (!dir_emit(ctx, "..", 2,
 281                             (dp->parent == NULL ?
 282                              OPENPROM_ROOT_INO :
 283                              dp->parent->unique_id), DT_DIR))
 284                         goto out;
 285                 ctx->pos = 2;
 286         }
 287         i = ctx->pos - 2;
 288
 289         /* First, the children nodes as directories.  */
 290         child = dp->child;
 291         while (i && child) {
 292                 child = child->sibling;
 293                 i--;
 294         }
 295         while (child) {
 296                 if (!dir_emit(ctx,
 297                             child->path_component_name,
 298                             strlen(child->path_component_name),
 299                             child->unique_id, DT_DIR))
 300                         goto out;
 301
 302                 ctx->pos++;
 303                 child = child->sibling;
 304         }
 305
 306         /* Next, the properties as files.  */
 307         prop = dp->properties;
 308         while (i && prop) {
 309                 prop = prop->next;
 310                 i--;
 311         }
 312         while (prop) {
 313                 if (!dir_emit(ctx, prop->name, strlen(prop->name),
 314                             prop->unique_id, DT_REG))
 315                         goto out;
 316
 317                 ctx->pos++;
 318                 prop = prop->next;
 319         }
 320
 321 out:
 322         mutex_unlock(&op_mutex);
 323         return 0;
 324 }
 325
 326 static struct kmem_cache *op_inode_cachep;
 327
 328 static struct inode *openprom_alloc_inode(struct super_block *sb)
 329 {
 330         struct op_inode_info *oi;
 331
 332         oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
 333         if (!oi)
 334                 return NULL;
 335
 336         return &oi->vfs_inode;
 337 }
 338
 339 static void openprom_i_callback(struct rcu_head *head)
 340 {
 341         struct inode *inode = container_of(head, struct inode, i_rcu);
 342         kmem_cache_free(op_inode_cachep, OP_I(inode));
 343 }
 344
 345 static void openprom_destroy_inode(struct inode *inode)
 346 {
 347         call_rcu(&inode->i_rcu, openprom_i_callback);
 348 }
 349
 350 static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
 351 {
 352         struct inode *inode;
 353
 354         inode = iget_locked(sb, ino);
 355         if (!inode)
 356                 return ERR_PTR(-ENOMEM);
 357         if (inode->i_state & I_NEW) {
 358                 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 359                 if (inode->i_ino == OPENPROM_ROOT_INO) {
 360                         inode->i_op = &openprom_inode_operations;
 361                         inode->i_fop = &openprom_operations;
 362                         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 363                 }
 364                 unlock_new_inode(inode);
 365         }
 366         return inode;
 367 }
 368
 369 static int openprom_remount(struct super_block *sb, int *flags, char *data)
 370 {
 371         sync_filesystem(sb);
 372         *flags |= MS_NOATIME;
 373         return 0;
 374 }
 375
 376 static const struct super_operations openprom_sops = {
 377         .alloc_inode    = openprom_alloc_inode,
 378         .destroy_inode  = openprom_destroy_inode,
 379         .statfs         = simple_statfs,
 380         .remount_fs     = openprom_remount,
 381 };
 382
 383 static int openprom_fill_super(struct super_block *s, void *data, int silent)
 384 {
 385         struct inode *root_inode;
 386         struct op_inode_info *oi;
 387         int ret;
 388
 389         s->s_flags |= MS_NOATIME;
 390         s->s_blocksize = 1024;
 391         s->s_blocksize_bits = 10;
 392         s->s_magic = OPENPROM_SUPER_MAGIC;
 393         s->s_op = &openprom_sops;
 394         s->s_time_gran = 1;
 395         root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
 396         if (IS_ERR(root_inode)) {
 397                 ret = PTR_ERR(root_inode);
 398                 goto out_no_root;
 399         }
 400
 401         oi = OP_I(root_inode);
 402         oi->type = op_inode_node;
 403         oi->u.node = of_find_node_by_path("/");
 404
 405         s->s_root = d_make_root(root_inode);
 406         if (!s->s_root)
 407                 goto out_no_root_dentry;
 408         return 0;
 409
 410 out_no_root_dentry:
 411         ret = -ENOMEM;
 412 out_no_root:
 413         printk("openprom_fill_super: get root inode failed\n");
 414         return ret;
 415 }
 416
 417 static struct dentry *openprom_mount(struct file_system_type *fs_type,
 418         int flags, const char *dev_name, void *data)
 419 {
 420         return mount_single(fs_type, flags, data, openprom_fill_super);
 421 }
 422
 423 static struct file_system_type openprom_fs_type = {
 424         .owner          = THIS_MODULE,
 425         .name           = "openpromfs",
 426         .mount          = openprom_mount,
 427         .kill_sb        = kill_anon_super,
 428 };
 429 MODULE_ALIAS_FS("openpromfs");
 430
 431 static void op_inode_init_once(void *data)
 432 {
 433         struct op_inode_info *oi = (struct op_inode_info *) data;
 434
 435         inode_init_once(&oi->vfs_inode);
 436 }
 437
 438 static int __init init_openprom_fs(void)
 439 {
 440         int err;
 441
 442         op_inode_cachep = kmem_cache_create("op_inode_cache",
 443                                             sizeof(struct op_inode_info),
 444                                             0,
 445                                             (SLAB_RECLAIM_ACCOUNT |
 446                                              SLAB_MEM_SPREAD | SLAB_ACCOUNT),
 447                                             op_inode_init_once);
 448         if (!op_inode_cachep)
 449                 return -ENOMEM;
 450
 451         err = register_filesystem(&openprom_fs_type);
 452         if (err)
 453                 kmem_cache_destroy(op_inode_cachep);
 454
 455         return err;
 456 }
 457
 458 static void __exit exit_openprom_fs(void)
 459 {
 460         unregister_filesystem(&openprom_fs_type);
 461         /*
 462          * Make sure all delayed rcu free inodes are flushed before we
 463          * destroy cache.
 464          */
 465         rcu_barrier();
 466         kmem_cache_destroy(op_inode_cachep);
 467 }
 468
 469 module_init(init_openprom_fs)
 470 module_exit(exit_openprom_fs)
 471 MODULE_LICENSE("GPL");