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 <asm/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 inline struct op_inode_info *OP_I(struct inode *inode)
  42 {
  43         return container_of(inode, struct op_inode_info, vfs_inode);
  44 }
  45
  46 static int is_string(unsigned char *p, int len)
  47 {
  48         int i;
  49
  50         for (i = 0; i < len; i++) {
  51                 unsigned char val = p[i];
  52
  53                 if ((i && !val) ||
  54                     (val >= ' ' && val <= '~'))
  55                         continue;
  56
  57                 return 0;
  58         }
  59
  60         return 1;
  61 }
  62
  63 static int property_show(struct seq_file *f, void *v)
  64 {
  65         struct property *prop = f->private;
  66         void *pval;
  67         int len;
  68
  69         len = prop->length;
  70         pval = prop->value;
  71
  72         if (is_string(pval, len)) {
  73                 while (len > 0) {
  74                         int n = strlen(pval);
  75
  76                         seq_printf(f, "%s", (char *) pval);
  77
  78                         /* Skip over the NULL byte too.  */
  79                         pval += n + 1;
  80                         len -= n + 1;
  81
  82                         if (len > 0)
  83                                 seq_printf(f, " + ");
  84                 }
  85         } else {
  86                 if (len & 3) {
  87                         while (len) {
  88                                 len--;
  89                                 if (len)
  90                                         seq_printf(f, "%02x.",
  91                                                    *(unsigned char *) pval);
  92                                 else
  93                                         seq_printf(f, "%02x",
  94                                                    *(unsigned char *) pval);
  95                                 pval++;
  96                         }
  97                 } else {
  98                         while (len >= 4) {
  99                                 len -= 4;
 100
 101                                 if (len)
 102                                         seq_printf(f, "%08x.",
 103                                                    *(unsigned int *) pval);
 104                                 else
 105                                         seq_printf(f, "%08x",
 106                                                    *(unsigned int *) pval);
 107                                 pval += 4;
 108                         }
 109                 }
 110         }
 111         seq_printf(f, "\n");
 112
 113         return 0;
 114 }
 115
 116 static void *property_start(struct seq_file *f, loff_t *pos)
 117 {
 118         if (*pos == 0)
 119                 return pos;
 120         return NULL;
 121 }
 122
 123 static void *property_next(struct seq_file *f, void *v, loff_t *pos)
 124 {
 125         (*pos)++;
 126         return NULL;
 127 }
 128
 129 static void property_stop(struct seq_file *f, void *v)
 130 {
 131         /* Nothing to do */
 132 }
 133
 134 static struct seq_operations property_op = {
 135         .start          = property_start,
 136         .next           = property_next,
 137         .stop           = property_stop,
 138         .show           = property_show
 139 };
 140
 141 static int property_open(struct inode *inode, struct file *file)
 142 {
 143         struct op_inode_info *oi = OP_I(inode);
 144         int ret;
 145
 146         BUG_ON(oi->type != op_inode_prop);
 147
 148         ret = seq_open(file, &property_op);
 149         if (!ret) {
 150                 struct seq_file *m = file->private_data;
 151                 m->private = oi->u.prop;
 152         }
 153         return ret;
 154 }
 155
 156 static const struct file_operations openpromfs_prop_ops = {
 157         .open           = property_open,
 158         .read           = seq_read,
 159         .llseek         = seq_lseek,
 160         .release        = seq_release,
 161 };
 162
 163 static int openpromfs_readdir(struct file *, void *, filldir_t);
 164
 165 static const struct file_operations openprom_operations = {
 166         .read           = generic_read_dir,
 167         .readdir        = openpromfs_readdir,
 168 };
 169
 170 static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, struct nameidata *);
 171
 172 static const struct inode_operations openprom_inode_operations = {
 173         .lookup         = openpromfs_lookup,
 174 };
 175
 176 static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 177 {
 178         struct op_inode_info *ent_oi, *oi = OP_I(dir);
 179         struct device_node *dp, *child;
 180         struct property *prop;
 181         enum op_inode_type ent_type;
 182         union op_inode_data ent_data;
 183         const char *name;
 184         struct inode *inode;
 185         unsigned int ino;
 186         int len;
 187
 188         BUG_ON(oi->type != op_inode_node);
 189
 190         dp = oi->u.node;
 191
 192         name = dentry->d_name.name;
 193         len = dentry->d_name.len;
 194
 195         mutex_lock(&op_mutex);
 196
 197         child = dp->child;
 198         while (child) {
 199                 int n = strlen(child->path_component_name);
 200
 201                 if (len == n &&
 202                     !strncmp(child->path_component_name, name, len)) {
 203                         ent_type = op_inode_node;
 204                         ent_data.node = child;
 205                         ino = child->unique_id;
 206                         goto found;
 207                 }
 208                 child = child->sibling;
 209         }
 210
 211         prop = dp->properties;
 212         while (prop) {
 213                 int n = strlen(prop->name);
 214
 215                 if (len == n && !strncmp(prop->name, name, len)) {
 216                         ent_type = op_inode_prop;
 217                         ent_data.prop = prop;
 218                         ino = prop->unique_id;
 219                         goto found;
 220                 }
 221
 222                 prop = prop->next;
 223         }
 224
 225         mutex_unlock(&op_mutex);
 226         return ERR_PTR(-ENOENT);
 227
 228 found:
 229         inode = iget(dir->i_sb, ino);
 230         mutex_unlock(&op_mutex);
 231         if (!inode)
 232                 return ERR_PTR(-EINVAL);
 233         ent_oi = OP_I(inode);
 234         ent_oi->type = ent_type;
 235         ent_oi->u = ent_data;
 236
 237         switch (ent_type) {
 238         case op_inode_node:
 239                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 240                 inode->i_op = &openprom_inode_operations;
 241                 inode->i_fop = &openprom_operations;
 242                 inode->i_nlink = 2;
 243                 break;
 244         case op_inode_prop:
 245                 if (!strcmp(dp->name, "options") && (len == 17) &&
 246                     !strncmp (name, "security-password", 17))
 247                         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 248                 else
 249                         inode->i_mode = S_IFREG | S_IRUGO;
 250                 inode->i_fop = &openpromfs_prop_ops;
 251                 inode->i_nlink = 1;
 252                 inode->i_size = ent_oi->u.prop->length;
 253                 break;
 254         }
 255
 256         inode->i_gid = 0;
 257         inode->i_uid = 0;
 258
 259         d_add(dentry, inode);
 260         return NULL;
 261 }
 262
 263 static int openpromfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 264 {
 265         struct inode *inode = filp->f_path.dentry->d_inode;
 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         unsigned int ino;
 271         int i;
 272
 273         mutex_lock(&op_mutex);
 274
 275         ino = inode->i_ino;
 276         i = filp->f_pos;
 277         switch (i) {
 278         case 0:
 279                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
 280                         goto out;
 281                 i++;
 282                 filp->f_pos++;
 283                 /* fall thru */
 284         case 1:
 285                 if (filldir(dirent, "..", 2, i,
 286                             (dp->parent == NULL ?
 287                              OPENPROM_ROOT_INO :
 288                              dp->parent->unique_id), DT_DIR) < 0)
 289                         goto out;
 290                 i++;
 291                 filp->f_pos++;
 292                 /* fall thru */
 293         default:
 294                 i -= 2;
 295
 296                 /* First, the children nodes as directories.  */
 297                 child = dp->child;
 298                 while (i && child) {
 299                         child = child->sibling;
 300                         i--;
 301                 }
 302                 while (child) {
 303                         if (filldir(dirent,
 304                                     child->path_component_name,
 305                                     strlen(child->path_component_name),
 306                                     filp->f_pos, child->unique_id, DT_DIR) < 0)
 307                                 goto out;
 308
 309                         filp->f_pos++;
 310                         child = child->sibling;
 311                 }
 312
 313                 /* Next, the properties as files.  */
 314                 prop = dp->properties;
 315                 while (i && prop) {
 316                         prop = prop->next;
 317                         i--;
 318                 }
 319                 while (prop) {
 320                         if (filldir(dirent, prop->name, strlen(prop->name),
 321                                     filp->f_pos, prop->unique_id, DT_REG) < 0)
 322                                 goto out;
 323
 324                         filp->f_pos++;
 325                         prop = prop->next;
 326                 }
 327         }
 328 out:
 329         mutex_unlock(&op_mutex);
 330         return 0;
 331 }
 332
 333 static struct kmem_cache *op_inode_cachep;
 334
 335 static struct inode *openprom_alloc_inode(struct super_block *sb)
 336 {
 337         struct op_inode_info *oi;
 338
 339         oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
 340         if (!oi)
 341                 return NULL;
 342
 343         return &oi->vfs_inode;
 344 }
 345
 346 static void openprom_destroy_inode(struct inode *inode)
 347 {
 348         kmem_cache_free(op_inode_cachep, OP_I(inode));
 349 }
 350
 351 static void openprom_read_inode(struct inode * inode)
 352 {
 353         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 354         if (inode->i_ino == OPENPROM_ROOT_INO) {
 355                 inode->i_op = &openprom_inode_operations;
 356                 inode->i_fop = &openprom_operations;
 357                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 358         }
 359 }
 360
 361 static int openprom_remount(struct super_block *sb, int *flags, char *data)
 362 {
 363         *flags |= MS_NOATIME;
 364         return 0;
 365 }
 366
 367 static const struct super_operations openprom_sops = {
 368         .alloc_inode    = openprom_alloc_inode,
 369         .destroy_inode  = openprom_destroy_inode,
 370         .read_inode     = openprom_read_inode,
 371         .statfs         = simple_statfs,
 372         .remount_fs     = openprom_remount,
 373 };
 374
 375 static int openprom_fill_super(struct super_block *s, void *data, int silent)
 376 {
 377         struct inode *root_inode;
 378         struct op_inode_info *oi;
 379
 380         s->s_flags |= MS_NOATIME;
 381         s->s_blocksize = 1024;
 382         s->s_blocksize_bits = 10;
 383         s->s_magic = OPENPROM_SUPER_MAGIC;
 384         s->s_op = &openprom_sops;
 385         s->s_time_gran = 1;
 386         root_inode = iget(s, OPENPROM_ROOT_INO);
 387         if (!root_inode)
 388                 goto out_no_root;
 389
 390         oi = OP_I(root_inode);
 391         oi->type = op_inode_node;
 392         oi->u.node = of_find_node_by_path("/");
 393
 394         s->s_root = d_alloc_root(root_inode);
 395         if (!s->s_root)
 396                 goto out_no_root;
 397         return 0;
 398
 399 out_no_root:
 400         printk("openprom_fill_super: get root inode failed\n");
 401         iput(root_inode);
 402         return -ENOMEM;
 403 }
 404
 405 static int openprom_get_sb(struct file_system_type *fs_type,
 406         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 407 {
 408         return get_sb_single(fs_type, flags, data, openprom_fill_super, mnt);
 409 }
 410
 411 static struct file_system_type openprom_fs_type = {
 412         .owner          = THIS_MODULE,
 413         .name           = "openpromfs",
 414         .get_sb         = openprom_get_sb,
 415         .kill_sb        = kill_anon_super,
 416 };
 417
 418 static void op_inode_init_once(void *data, struct kmem_cache * cachep, unsigned long flags)
 419 {
 420         struct op_inode_info *oi = (struct op_inode_info *) data;
 421
 422         inode_init_once(&oi->vfs_inode);
 423 }
 424
 425 static int __init init_openprom_fs(void)
 426 {
 427         int err;
 428
 429         op_inode_cachep = kmem_cache_create("op_inode_cache",
 430                                             sizeof(struct op_inode_info),
 431                                             0,
 432                                             (SLAB_RECLAIM_ACCOUNT |
 433                                              SLAB_MEM_SPREAD),
 434                                             op_inode_init_once, NULL);
 435         if (!op_inode_cachep)
 436                 return -ENOMEM;
 437
 438         err = register_filesystem(&openprom_fs_type);
 439         if (err)
 440                 kmem_cache_destroy(op_inode_cachep);
 441
 442         return err;
 443 }
 444
 445 static void __exit exit_openprom_fs(void)
 446 {
 447         unregister_filesystem(&openprom_fs_type);
 448         kmem_cache_destroy(op_inode_cachep);
 449 }
 450
 451 module_init(init_openprom_fs)
 452 module_exit(exit_openprom_fs)
 453 MODULE_LICENSE("GPL");