xref: /openbmc/linux/fs/openpromfs/inode.c (revision f42b3800) 
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(struct kmem_cache * cachep, 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");
469