1 // SPDX-License-Identifier: GPL-2.0-only
2 /* inode.c: /proc/openprom handling routines
3 *
4 * Copyright (C) 1996-1999 Jakub Jelinek (jakub@redhat.com)
5 * Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
6 */
7
8 #include <linux/module.h>
9 #include <linux/types.h>
10 #include <linux/string.h>
11 #include <linux/fs.h>
12 #include <linux/fs_context.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/seq_file.h>
16 #include <linux/magic.h>
17
18 #include <asm/openprom.h>
19 #include <asm/oplib.h>
20 #include <asm/prom.h>
21 #include <linux/uaccess.h>
22
23 static DEFINE_MUTEX(op_mutex);
24
25 #define OPENPROM_ROOT_INO 0
26
27 enum op_inode_type {
28 op_inode_node,
29 op_inode_prop,
30 };
31
32 union op_inode_data {
33 struct device_node *node;
34 struct property *prop;
35 };
36
37 struct op_inode_info {
38 struct inode vfs_inode;
39 enum op_inode_type type;
40 union op_inode_data u;
41 };
42
43 static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
44
OP_I(struct inode * inode)45 static inline struct op_inode_info *OP_I(struct inode *inode)
46 {
47 return container_of(inode, struct op_inode_info, vfs_inode);
48 }
49
is_string(unsigned char * p,int len)50 static int is_string(unsigned char *p, int len)
51 {
52 int i;
53
54 for (i = 0; i < len; i++) {
55 unsigned char val = p[i];
56
57 if ((i && !val) ||
58 (val >= ' ' && val <= '~'))
59 continue;
60
61 return 0;
62 }
63
64 return 1;
65 }
66
property_show(struct seq_file * f,void * v)67 static int property_show(struct seq_file *f, void *v)
68 {
69 struct property *prop = f->private;
70 void *pval;
71 int len;
72
73 len = prop->length;
74 pval = prop->value;
75
76 if (is_string(pval, len)) {
77 while (len > 0) {
78 int n = strlen(pval);
79
80 seq_printf(f, "%s", (char *) pval);
81
82 /* Skip over the NULL byte too. */
83 pval += n + 1;
84 len -= n + 1;
85
86 if (len > 0)
87 seq_printf(f, " + ");
88 }
89 } else {
90 if (len & 3) {
91 while (len) {
92 len--;
93 if (len)
94 seq_printf(f, "%02x.",
95 *(unsigned char *) pval);
96 else
97 seq_printf(f, "%02x",
98 *(unsigned char *) pval);
99 pval++;
100 }
101 } else {
102 while (len >= 4) {
103 len -= 4;
104
105 if (len)
106 seq_printf(f, "%08x.",
107 *(unsigned int *) pval);
108 else
109 seq_printf(f, "%08x",
110 *(unsigned int *) pval);
111 pval += 4;
112 }
113 }
114 }
115 seq_printf(f, "\n");
116
117 return 0;
118 }
119
property_start(struct seq_file * f,loff_t * pos)120 static void *property_start(struct seq_file *f, loff_t *pos)
121 {
122 if (*pos == 0)
123 return pos;
124 return NULL;
125 }
126
property_next(struct seq_file * f,void * v,loff_t * pos)127 static void *property_next(struct seq_file *f, void *v, loff_t *pos)
128 {
129 (*pos)++;
130 return NULL;
131 }
132
property_stop(struct seq_file * f,void * v)133 static void property_stop(struct seq_file *f, void *v)
134 {
135 /* Nothing to do */
136 }
137
138 static const struct seq_operations property_op = {
139 .start = property_start,
140 .next = property_next,
141 .stop = property_stop,
142 .show = property_show
143 };
144
property_open(struct inode * inode,struct file * file)145 static int property_open(struct inode *inode, struct file *file)
146 {
147 struct op_inode_info *oi = OP_I(inode);
148 int ret;
149
150 BUG_ON(oi->type != op_inode_prop);
151
152 ret = seq_open(file, &property_op);
153 if (!ret) {
154 struct seq_file *m = file->private_data;
155 m->private = oi->u.prop;
156 }
157 return ret;
158 }
159
160 static const struct file_operations openpromfs_prop_ops = {
161 .open = property_open,
162 .read = seq_read,
163 .llseek = seq_lseek,
164 .release = seq_release,
165 };
166
167 static int openpromfs_readdir(struct file *, struct dir_context *);
168
169 static const struct file_operations openprom_operations = {
170 .read = generic_read_dir,
171 .iterate_shared = openpromfs_readdir,
172 .llseek = generic_file_llseek,
173 };
174
175 static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);
176
177 static const struct inode_operations openprom_inode_operations = {
178 .lookup = openpromfs_lookup,
179 };
180
openpromfs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)181 static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
182 {
183 struct op_inode_info *ent_oi, *oi = OP_I(dir);
184 struct device_node *dp, *child;
185 struct property *prop;
186 enum op_inode_type ent_type;
187 union op_inode_data ent_data;
188 const char *name;
189 struct inode *inode;
190 unsigned int ino;
191 int len;
192
193 BUG_ON(oi->type != op_inode_node);
194
195 dp = oi->u.node;
196
197 name = dentry->d_name.name;
198 len = dentry->d_name.len;
199
200 mutex_lock(&op_mutex);
201
202 child = dp->child;
203 while (child) {
204 const char *node_name = kbasename(child->full_name);
205 int n = strlen(node_name);
206
207 if (len == n &&
208 !strncmp(node_name, name, len)) {
209 ent_type = op_inode_node;
210 ent_data.node = child;
211 ino = child->unique_id;
212 goto found;
213 }
214 child = child->sibling;
215 }
216
217 prop = dp->properties;
218 while (prop) {
219 int n = strlen(prop->name);
220
221 if (len == n && !strncmp(prop->name, name, len)) {
222 ent_type = op_inode_prop;
223 ent_data.prop = prop;
224 ino = prop->unique_id;
225 goto found;
226 }
227
228 prop = prop->next;
229 }
230
231 mutex_unlock(&op_mutex);
232 return ERR_PTR(-ENOENT);
233
234 found:
235 inode = openprom_iget(dir->i_sb, ino);
236 mutex_unlock(&op_mutex);
237 if (IS_ERR(inode))
238 return ERR_CAST(inode);
239 if (inode->i_state & I_NEW) {
240 inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
241 ent_oi = OP_I(inode);
242 ent_oi->type = ent_type;
243 ent_oi->u = ent_data;
244
245 switch (ent_type) {
246 case op_inode_node:
247 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
248 inode->i_op = &openprom_inode_operations;
249 inode->i_fop = &openprom_operations;
250 set_nlink(inode, 2);
251 break;
252 case op_inode_prop:
253 if (of_node_name_eq(dp, "options") && (len == 17) &&
254 !strncmp (name, "security-password", 17))
255 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
256 else
257 inode->i_mode = S_IFREG | S_IRUGO;
258 inode->i_fop = &openpromfs_prop_ops;
259 set_nlink(inode, 1);
260 inode->i_size = ent_oi->u.prop->length;
261 break;
262 }
263 unlock_new_inode(inode);
264 }
265
266 return d_splice_alias(inode, dentry);
267 }
268
openpromfs_readdir(struct file * file,struct dir_context * ctx)269 static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
270 {
271 struct inode *inode = file_inode(file);
272 struct op_inode_info *oi = OP_I(inode);
273 struct device_node *dp = oi->u.node;
274 struct device_node *child;
275 struct property *prop;
276 int i;
277
278 mutex_lock(&op_mutex);
279
280 if (ctx->pos == 0) {
281 if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
282 goto out;
283 ctx->pos = 1;
284 }
285 if (ctx->pos == 1) {
286 if (!dir_emit(ctx, "..", 2,
287 (dp->parent == NULL ?
288 OPENPROM_ROOT_INO :
289 dp->parent->unique_id), DT_DIR))
290 goto out;
291 ctx->pos = 2;
292 }
293 i = ctx->pos - 2;
294
295 /* First, the children nodes as directories. */
296 child = dp->child;
297 while (i && child) {
298 child = child->sibling;
299 i--;
300 }
301 while (child) {
302 if (!dir_emit(ctx,
303 kbasename(child->full_name),
304 strlen(kbasename(child->full_name)),
305 child->unique_id, DT_DIR))
306 goto out;
307
308 ctx->pos++;
309 child = child->sibling;
310 }
311
312 /* Next, the properties as files. */
313 prop = dp->properties;
314 while (i && prop) {
315 prop = prop->next;
316 i--;
317 }
318 while (prop) {
319 if (!dir_emit(ctx, prop->name, strlen(prop->name),
320 prop->unique_id, DT_REG))
321 goto out;
322
323 ctx->pos++;
324 prop = prop->next;
325 }
326
327 out:
328 mutex_unlock(&op_mutex);
329 return 0;
330 }
331
332 static struct kmem_cache *op_inode_cachep;
333
openprom_alloc_inode(struct super_block * sb)334 static struct inode *openprom_alloc_inode(struct super_block *sb)
335 {
336 struct op_inode_info *oi;
337
338 oi = alloc_inode_sb(sb, op_inode_cachep, GFP_KERNEL);
339 if (!oi)
340 return NULL;
341
342 return &oi->vfs_inode;
343 }
344
openprom_free_inode(struct inode * inode)345 static void openprom_free_inode(struct inode *inode)
346 {
347 kmem_cache_free(op_inode_cachep, OP_I(inode));
348 }
349
openprom_iget(struct super_block * sb,ino_t ino)350 static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
351 {
352 struct inode *inode = iget_locked(sb, ino);
353 if (!inode)
354 inode = ERR_PTR(-ENOMEM);
355 return inode;
356 }
357
openprom_remount(struct super_block * sb,int * flags,char * data)358 static int openprom_remount(struct super_block *sb, int *flags, char *data)
359 {
360 sync_filesystem(sb);
361 *flags |= SB_NOATIME;
362 return 0;
363 }
364
365 static const struct super_operations openprom_sops = {
366 .alloc_inode = openprom_alloc_inode,
367 .free_inode = openprom_free_inode,
368 .statfs = simple_statfs,
369 .remount_fs = openprom_remount,
370 };
371
openprom_fill_super(struct super_block * s,struct fs_context * fc)372 static int openprom_fill_super(struct super_block *s, struct fs_context *fc)
373 {
374 struct inode *root_inode;
375 struct op_inode_info *oi;
376 int ret;
377
378 s->s_flags |= SB_NOATIME;
379 s->s_blocksize = 1024;
380 s->s_blocksize_bits = 10;
381 s->s_magic = OPENPROM_SUPER_MAGIC;
382 s->s_op = &openprom_sops;
383 s->s_time_gran = 1;
384 root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
385 if (IS_ERR(root_inode)) {
386 ret = PTR_ERR(root_inode);
387 goto out_no_root;
388 }
389
390 root_inode->i_mtime = root_inode->i_atime = inode_set_ctime_current(root_inode);
391 root_inode->i_op = &openprom_inode_operations;
392 root_inode->i_fop = &openprom_operations;
393 root_inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
394 oi = OP_I(root_inode);
395 oi->type = op_inode_node;
396 oi->u.node = of_find_node_by_path("/");
397 unlock_new_inode(root_inode);
398
399 s->s_root = d_make_root(root_inode);
400 if (!s->s_root)
401 goto out_no_root_dentry;
402 return 0;
403
404 out_no_root_dentry:
405 ret = -ENOMEM;
406 out_no_root:
407 printk("openprom_fill_super: get root inode failed\n");
408 return ret;
409 }
410
openpromfs_get_tree(struct fs_context * fc)411 static int openpromfs_get_tree(struct fs_context *fc)
412 {
413 return get_tree_single(fc, openprom_fill_super);
414 }
415
416 static const struct fs_context_operations openpromfs_context_ops = {
417 .get_tree = openpromfs_get_tree,
418 };
419
openpromfs_init_fs_context(struct fs_context * fc)420 static int openpromfs_init_fs_context(struct fs_context *fc)
421 {
422 fc->ops = &openpromfs_context_ops;
423 return 0;
424 }
425
426 static struct file_system_type openprom_fs_type = {
427 .owner = THIS_MODULE,
428 .name = "openpromfs",
429 .init_fs_context = openpromfs_init_fs_context,
430 .kill_sb = kill_anon_super,
431 };
432 MODULE_ALIAS_FS("openpromfs");
433
op_inode_init_once(void * data)434 static void op_inode_init_once(void *data)
435 {
436 struct op_inode_info *oi = (struct op_inode_info *) data;
437
438 inode_init_once(&oi->vfs_inode);
439 }
440
init_openprom_fs(void)441 static int __init init_openprom_fs(void)
442 {
443 int err;
444
445 op_inode_cachep = kmem_cache_create("op_inode_cache",
446 sizeof(struct op_inode_info),
447 0,
448 (SLAB_RECLAIM_ACCOUNT |
449 SLAB_MEM_SPREAD | SLAB_ACCOUNT),
450 op_inode_init_once);
451 if (!op_inode_cachep)
452 return -ENOMEM;
453
454 err = register_filesystem(&openprom_fs_type);
455 if (err)
456 kmem_cache_destroy(op_inode_cachep);
457
458 return err;
459 }
460
exit_openprom_fs(void)461 static void __exit exit_openprom_fs(void)
462 {
463 unregister_filesystem(&openprom_fs_type);
464 /*
465 * Make sure all delayed rcu free inodes are flushed before we
466 * destroy cache.
467 */
468 rcu_barrier();
469 kmem_cache_destroy(op_inode_cachep);
470 }
471
472 module_init(init_openprom_fs)
473 module_exit(exit_openprom_fs)
474 MODULE_LICENSE("GPL");
475