xref: /openbmc/linux/fs/openpromfs/inode.c (revision 1c2dd16a) 
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");
472