summaryrefslogtreecommitdiffstats
path: root/fs/openpromfs/inode.c
blob: 15e4500cda3ee28f56957d03adf120ae8d9f73fb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
/* inode.c: /proc/openprom handling routines
 *
 * Copyright (C) 1996-1999 Jakub Jelinek  (jakub@redhat.com)
 * Copyright (C) 1998      Eddie C. Dost  (ecd@skynet.be)
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/magic.h>

#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/uaccess.h>

static DEFINE_MUTEX(op_mutex);

#define OPENPROM_ROOT_INO	0

enum op_inode_type {
	op_inode_node,
	op_inode_prop,
};

union op_inode_data {
	struct device_node	*node;
	struct property		*prop;
};

struct op_inode_info {
	struct inode		vfs_inode;
	enum op_inode_type	type;
	union op_inode_data	u;
};

static struct inode *openprom_iget(struct super_block *sb, ino_t ino);

static inline struct op_inode_info *OP_I(struct inode *inode)
{
	return container_of(inode, struct op_inode_info, vfs_inode);
}

static int is_string(unsigned char *p, int len)
{
	int i;

	for (i = 0; i < len; i++) {
		unsigned char val = p[i];

		if ((i && !val) ||
		    (val >= ' ' && val <= '~'))
			continue;

		return 0;
	}

	return 1;
}

static int property_show(struct seq_file *f, void *v)
{
	struct property *prop = f->private;
	void *pval;
	int len;

	len = prop->length;
	pval = prop->value;

	if (is_string(pval, len)) {
		while (len > 0) {
			int n = strlen(pval);

			seq_printf(f, "%s", (char *) pval);

			/* Skip over the NULL byte too.  */
			pval += n + 1;
			len -= n + 1;

			if (len > 0)
				seq_printf(f, " + ");
		}
	} else {
		if (len & 3) {
			while (len) {
				len--;
				if (len)
					seq_printf(f, "%02x.",
						   *(unsigned char *) pval);
				else
					seq_printf(f, "%02x",
						   *(unsigned char *) pval);
				pval++;
			}
		} else {
			while (len >= 4) {
				len -= 4;

				if (len)
					seq_printf(f, "%08x.",
						   *(unsigned int *) pval);
				else
					seq_printf(f, "%08x",
						   *(unsigned int *) pval);
				pval += 4;
			}
		}
	}
	seq_printf(f, "\n");

	return 0;
}

static void *property_start(struct seq_file *f, loff_t *pos)
{
	if (*pos == 0)
		return pos;
	return NULL;
}

static void *property_next(struct seq_file *f, void *v, loff_t *pos)
{
	(*pos)++;
	return NULL;
}

static void property_stop(struct seq_file *f, void *v)
{
	/* Nothing to do */
}

static const struct seq_operations property_op = {
	.start		= property_start,
	.next		= property_next,
	.stop		= property_stop,
	.show		= property_show
};

static int property_open(struct inode *inode, struct file *file)
{
	struct op_inode_info *oi = OP_I(inode);
	int ret;

	BUG_ON(oi->type != op_inode_prop);

	ret = seq_open(file, &property_op);
	if (!ret) {
		struct seq_file *m = file->private_data;
		m->private = oi->u.prop;
	}
	return ret;
}

static const struct file_operations openpromfs_prop_ops = {
	.open		= property_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int openpromfs_readdir(struct file *, struct dir_context *);

static const struct file_operations openprom_operations = {
	.read		= generic_read_dir,
	.iterate	= openpromfs_readdir,
	.llseek		= generic_file_llseek,
};

static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);

static const struct inode_operations openprom_inode_operations = {
	.lookup		= openpromfs_lookup,
};

static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
	struct op_inode_info *ent_oi, *oi = OP_I(dir);
	struct device_node *dp, *child;
	struct property *prop;
	enum op_inode_type ent_type;
	union op_inode_data ent_data;
	const char *name;
	struct inode *inode;
	unsigned int ino;
	int len;
	
	BUG_ON(oi->type != op_inode_node);

	dp = oi->u.node;

	name = dentry->d_name.name;
	len = dentry->d_name.len;

	mutex_lock(&op_mutex);

	child = dp->child;
	while (child) {
		int n = strlen(child->path_component_name);

		if (len == n &&
		    !strncmp(child->path_component_name, name, len)) {
			ent_type = op_inode_node;
			ent_data.node = child;
			ino = child->unique_id;
			goto found;
		}
		child = child->sibling;
	}

	prop = dp->properties;
	while (prop) {
		int n = strlen(prop->name);

		if (len == n && !strncmp(prop->name, name, len)) {
			ent_type = op_inode_prop;
			ent_data.prop = prop;
			ino = prop->unique_id;
			goto found;
		}

		prop = prop->next;
	}

	mutex_unlock(&op_mutex);
	return ERR_PTR(-ENOENT);

found:
	inode = openprom_iget(dir->i_sb, ino);
	mutex_unlock(&op_mutex);
	if (IS_ERR(inode))
		return ERR_CAST(inode);
	ent_oi = OP_I(inode);
	ent_oi->type = ent_type;
	ent_oi->u = ent_data;

	switch (ent_type) {
	case op_inode_node:
		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
		inode->i_op = &openprom_inode_operations;
		inode->i_fop = &openprom_operations;
		set_nlink(inode, 2);
		break;
	case op_inode_prop:
		if (!strcmp(dp->name, "options") && (len == 17) &&
		    !strncmp (name, "security-password", 17))
			inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
		else
			inode->i_mode = S_IFREG | S_IRUGO;
		inode->i_fop = &openpromfs_prop_ops;
		set_nlink(inode, 1);
		inode->i_size = ent_oi->u.prop->length;
		break;
	}

	d_add(dentry, inode);
	return NULL;
}

static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct op_inode_info *oi = OP_I(inode);
	struct device_node *dp = oi->u.node;
	struct device_node *child;
	struct property *prop;
	int i;

	mutex_lock(&op_mutex);
	
	if (ctx->pos == 0) {
		if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
			goto out;
		ctx->pos = 1;
	}
	if (ctx->pos == 1) {
		if (!dir_emit(ctx, "..", 2,
			    (dp->parent == NULL ?
			     OPENPROM_ROOT_INO :
			     dp->parent->unique_id), DT_DIR))
			goto out;
		ctx->pos = 2;
	}
	i = ctx->pos - 2;

	/* First, the children nodes as directories.  */
	child = dp->child;
	while (i && child) {
		child = child->sibling;
		i--;
	}
	while (child) {
		if (!dir_emit(ctx,
			    child->path_component_name,
			    strlen(child->path_component_name),
			    child->unique_id, DT_DIR))
			goto out;

		ctx->pos++;
		child = child->sibling;
	}

	/* Next, the properties as files.  */
	prop = dp->properties;
	while (i && prop) {
		prop = prop->next;
		i--;
	}
	while (prop) {
		if (!dir_emit(ctx, prop->name, strlen(prop->name),
			    prop->unique_id, DT_REG))
			goto out;

		ctx->pos++;
		prop = prop->next;
	}

out:
	mutex_unlock(&op_mutex);
	return 0;
}

static struct kmem_cache *op_inode_cachep;

static struct inode *openprom_alloc_inode(struct super_block *sb)
{
	struct op_inode_info *oi;

	oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
	if (!oi)
		return NULL;

	return &oi->vfs_inode;
}

static void openprom_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(op_inode_cachep, OP_I(inode));
}

static void openprom_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, openprom_i_callback);
}

static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
{
	struct inode *inode;

	inode = iget_locked(sb, ino);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (inode->i_state & I_NEW) {
		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
		if (inode->i_ino == OPENPROM_ROOT_INO) {
			inode->i_op = &openprom_inode_operations;
			inode->i_fop = &openprom_operations;
			inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
		}
		unlock_new_inode(inode);
	}
	return inode;
}

static int openprom_remount(struct super_block *sb, int *flags, char *data)
{
	sync_filesystem(sb);
	*flags |= MS_NOATIME;
	return 0;
}

static const struct super_operations openprom_sops = {
	.alloc_inode	= openprom_alloc_inode,
	.destroy_inode	= openprom_destroy_inode,
	.statfs		= simple_statfs,
	.remount_fs	= openprom_remount,
};

static int openprom_fill_super(struct super_block *s, void *data, int silent)
{
	struct inode *root_inode;
	struct op_inode_info *oi;
	int ret;

	s->s_flags |= MS_NOATIME;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = OPENPROM_SUPER_MAGIC;
	s->s_op = &openprom_sops;
	s->s_time_gran = 1;
	root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
	if (IS_ERR(root_inode)) {
		ret = PTR_ERR(root_inode);
		goto out_no_root;
	}

	oi = OP_I(root_inode);
	oi->type = op_inode_node;
	oi->u.node = of_find_node_by_path("/");

	s->s_root = d_make_root(root_inode);
	if (!s->s_root)
		goto out_no_root_dentry;
	return 0;

out_no_root_dentry:
	ret = -ENOMEM;
out_no_root:
	printk("openprom_fill_super: get root inode failed\n");
	return ret;
}

static struct dentry *openprom_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_single(fs_type, flags, data, openprom_fill_super);
}

static struct file_system_type openprom_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "openpromfs",
	.mount		= openprom_mount,
	.kill_sb	= kill_anon_super,
};
MODULE_ALIAS_FS("openpromfs");

static void op_inode_init_once(void *data)
{
	struct op_inode_info *oi = (struct op_inode_info *) data;

	inode_init_once(&oi->vfs_inode);
}

static int __init init_openprom_fs(void)
{
	int err;

	op_inode_cachep = kmem_cache_create("op_inode_cache",
					    sizeof(struct op_inode_info),
					    0,
					    (SLAB_RECLAIM_ACCOUNT |
					     SLAB_MEM_SPREAD),
					    op_inode_init_once);
	if (!op_inode_cachep)
		return -ENOMEM;

	err = register_filesystem(&openprom_fs_type);
	if (err)
		kmem_cache_destroy(op_inode_cachep);

	return err;
}

static void __exit exit_openprom_fs(void)
{
	unregister_filesystem(&openprom_fs_type);
	/*
	 * Make sure all delayed rcu free inodes are flushed before we
	 * destroy cache.
	 */
	rcu_barrier();
	kmem_cache_destroy(op_inode_cachep);
}

module_init(init_openprom_fs)
module_exit(exit_openprom_fs)
MODULE_LICENSE("GPL");