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 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 *, void *, filldir_t);
 166
 167 static const struct file_operations openprom_operations = {
 168         .read           = generic_read_dir,
 169         .readdir        = openpromfs_readdir,
 170 };
 171
 172 static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, struct nameidata *);
 173
 174 static const struct inode_operations openprom_inode_operations = {
 175         .lookup         = openpromfs_lookup,
 176 };
 177
 178 static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 179 {
 180         struct op_inode_info *ent_oi, *oi = OP_I(dir);
 181         struct device_node *dp, *child;
 182         struct property *prop;
 183         enum op_inode_type ent_type;
 184         union op_inode_data ent_data;
 185         const char *name;
 186         struct inode *inode;
 187         unsigned int ino;
 188         int len;
 189
 190         BUG_ON(oi->type != op_inode_node);
 191
 192         dp = oi->u.node;
 193
 194         name = dentry->d_name.name;
 195         len = dentry->d_name.len;
 196
 197         mutex_lock(&op_mutex);
 198
 199         child = dp->child;
 200         while (child) {
 201                 int n = strlen(child->path_component_name);
 202
 203                 if (len == n &&
 204                     !strncmp(child->path_component_name, name, len)) {
 205                         ent_type = op_inode_node;
 206                         ent_data.node = child;
 207                         ino = child->unique_id;
 208                         goto found;
 209                 }
 210                 child = child->sibling;
 211         }
 212
 213         prop = dp->properties;
 214         while (prop) {
 215                 int n = strlen(prop->name);
 216
 217                 if (len == n && !strncmp(prop->name, name, len)) {
 218                         ent_type = op_inode_prop;
 219                         ent_data.prop = prop;
 220                         ino = prop->unique_id;
 221                         goto found;
 222                 }
 223
 224                 prop = prop->next;
 225         }
 226
 227         mutex_unlock(&op_mutex);
 228         return ERR_PTR(-ENOENT);
 229
 230 found:
 231         inode = openprom_iget(dir->i_sb, ino);
 232         mutex_unlock(&op_mutex);
 233         if (IS_ERR(inode))
 234                 return ERR_CAST(inode);
 235         ent_oi = OP_I(inode);
 236         ent_oi->type = ent_type;
 237         ent_oi->u = ent_data;
 238
 239         switch (ent_type) {
 240         case op_inode_node:
 241                 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 242                 inode->i_op = &openprom_inode_operations;
 243                 inode->i_fop = &openprom_operations;
 244                 inode->i_nlink = 2;
 245                 break;
 246         case op_inode_prop:
 247                 if (!strcmp(dp->name, "options") && (len == 17) &&
 248                     !strncmp (name, "security-password", 17))
 249                         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 250                 else
 251                         inode->i_mode = S_IFREG | S_IRUGO;
 252                 inode->i_fop = &openpromfs_prop_ops;
 253                 inode->i_nlink = 1;
 254                 inode->i_size = ent_oi->u.prop->length;
 255                 break;
 256         }
 257
 258         inode->i_gid = 0;
 259         inode->i_uid = 0;
 260
 261         d_add(dentry, inode);
 262         return NULL;
 263 }
 264
 265 static int openpromfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 266 {
 267         struct inode *inode = filp->f_path.dentry->d_inode;
 268         struct op_inode_info *oi = OP_I(inode);
 269         struct device_node *dp = oi->u.node;
 270         struct device_node *child;
 271         struct property *prop;
 272         unsigned int ino;
 273         int i;
 274
 275         mutex_lock(&op_mutex);
 276
 277         ino = inode->i_ino;
 278         i = filp->f_pos;
 279         switch (i) {
 280         case 0:
 281                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
 282                         goto out;
 283                 i++;
 284                 filp->f_pos++;
 285                 /* fall thru */
 286         case 1:
 287                 if (filldir(dirent, "..", 2, i,
 288                             (dp->parent == NULL ?
 289                              OPENPROM_ROOT_INO :
 290                              dp->parent->unique_id), DT_DIR) < 0)
 291                         goto out;
 292                 i++;
 293                 filp->f_pos++;
 294                 /* fall thru */
 295         default:
 296                 i -= 2;
 297
 298                 /* First, the children nodes as directories.  */
 299                 child = dp->child;
 300                 while (i && child) {
 301                         child = child->sibling;
 302                         i--;
 303                 }
 304                 while (child) {
 305                         if (filldir(dirent,
 306                                     child->path_component_name,
 307                                     strlen(child->path_component_name),
 308                                     filp->f_pos, child->unique_id, DT_DIR) < 0)
 309                                 goto out;
 310
 311                         filp->f_pos++;
 312                         child = child->sibling;
 313                 }
 314
 315                 /* Next, the properties as files.  */
 316                 prop = dp->properties;
 317                 while (i && prop) {
 318                         prop = prop->next;
 319                         i--;
 320                 }
 321                 while (prop) {
 322                         if (filldir(dirent, prop->name, strlen(prop->name),
 323                                     filp->f_pos, prop->unique_id, DT_REG) < 0)
 324                                 goto out;
 325
 326                         filp->f_pos++;
 327                         prop = prop->next;
 328                 }
 329         }
 330 out:
 331         mutex_unlock(&op_mutex);
 332         return 0;
 333 }
 334
 335 static struct kmem_cache *op_inode_cachep;
 336
 337 static struct inode *openprom_alloc_inode(struct super_block *sb)
 338 {
 339         struct op_inode_info *oi;
 340
 341         oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
 342         if (!oi)
 343                 return NULL;
 344
 345         return &oi->vfs_inode;
 346 }
 347
 348 static void openprom_destroy_inode(struct inode *inode)
 349 {
 350         kmem_cache_free(op_inode_cachep, OP_I(inode));
 351 }
 352
 353 static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
 354 {
 355         struct inode *inode;
 356
 357         inode = iget_locked(sb, ino);
 358         if (!inode)
 359                 return ERR_PTR(-ENOMEM);
 360         if (inode->i_state & I_NEW) {
 361                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 362                 if (inode->i_ino == OPENPROM_ROOT_INO) {
 363                         inode->i_op = &openprom_inode_operations;
 364                         inode->i_fop = &openprom_operations;
 365                         inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 366                 }
 367                 unlock_new_inode(inode);
 368         }
 369         return inode;
 370 }
 371
 372 static int openprom_remount(struct super_block *sb, int *flags, char *data)
 373 {
 374         *flags |= MS_NOATIME;
 375         return 0;
 376 }
 377
 378 static const struct super_operations openprom_sops = {
 379         .alloc_inode    = openprom_alloc_inode,
 380         .destroy_inode  = openprom_destroy_inode,
 381         .statfs         = simple_statfs,
 382         .remount_fs     = openprom_remount,
 383 };
 384
 385 static int openprom_fill_super(struct super_block *s, void *data, int silent)
 386 {
 387         struct inode *root_inode;
 388         struct op_inode_info *oi;
 389         int ret;
 390
 391         s->s_flags |= MS_NOATIME;
 392         s->s_blocksize = 1024;
 393         s->s_blocksize_bits = 10;
 394         s->s_magic = OPENPROM_SUPER_MAGIC;
 395         s->s_op = &openprom_sops;
 396         s->s_time_gran = 1;
 397         root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
 398         if (IS_ERR(root_inode)) {
 399                 ret = PTR_ERR(root_inode);
 400                 goto out_no_root;
 401         }
 402
 403         oi = OP_I(root_inode);
 404         oi->type = op_inode_node;
 405         oi->u.node = of_find_node_by_path("/");
 406
 407         s->s_root = d_alloc_root(root_inode);
 408         if (!s->s_root)
 409                 goto out_no_root_dentry;
 410         return 0;
 411
 412 out_no_root_dentry:
 413         iput(root_inode);
 414         ret = -ENOMEM;
 415 out_no_root:
 416         printk("openprom_fill_super: get root inode failed\n");
 417         return ret;
 418 }
 419
 420 static int openprom_get_sb(struct file_system_type *fs_type,
 421         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 422 {
 423         return get_sb_single(fs_type, flags, data, openprom_fill_super, mnt);
 424 }
 425
 426 static struct file_system_type openprom_fs_type = {
 427         .owner          = THIS_MODULE,
 428         .name           = "openpromfs",
 429         .get_sb         = openprom_get_sb,
 430         .kill_sb        = kill_anon_super,
 431 };
 432
 433 static void op_inode_init_once(void *data)
 434 {
 435         struct op_inode_info *oi = (struct op_inode_info *) data;
 436
 437         inode_init_once(&oi->vfs_inode);
 438 }
 439
 440 static int __init init_openprom_fs(void)
 441 {
 442         int err;
 443
 444         op_inode_cachep = kmem_cache_create("op_inode_cache",
 445                                             sizeof(struct op_inode_info),
 446                                             0,
 447                                             (SLAB_RECLAIM_ACCOUNT |
 448                                              SLAB_MEM_SPREAD),
 449                                             op_inode_init_once);
 450         if (!op_inode_cachep)
 451                 return -ENOMEM;
 452
 453         err = register_filesystem(&openprom_fs_type);
 454         if (err)
 455                 kmem_cache_destroy(op_inode_cachep);
 456
 457         return err;
 458 }
 459
 460 static void __exit exit_openprom_fs(void)
 461 {
 462         unregister_filesystem(&openprom_fs_type);
 463         kmem_cache_destroy(op_inode_cachep);
 464 }
 465
 466 module_init(init_openprom_fs)
 467 module_exit(exit_openprom_fs)
 468 MODULE_LICENSE("GPL");