cfg80211: remove REGDOM_SET_BY_INIT
[linux-2.6.git] / lib / dynamic_printk.c
1 /*
2  * lib/dynamic_printk.c
3  *
4  * make pr_debug()/dev_dbg() calls runtime configurable based upon their
5  * their source module.
6  *
7  * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
8  */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/uaccess.h>
13 #include <linux/seq_file.h>
14 #include <linux/debugfs.h>
15 #include <linux/fs.h>
16
17 extern struct mod_debug __start___verbose[];
18 extern struct mod_debug __stop___verbose[];
19
20 struct debug_name {
21         struct hlist_node hlist;
22         struct hlist_node hlist2;
23         int hash1;
24         int hash2;
25         char *name;
26         int enable;
27         int type;
28 };
29
30 static int nr_entries;
31 static int num_enabled;
32 int dynamic_enabled = DYNAMIC_ENABLED_NONE;
33 static struct hlist_head module_table[DEBUG_HASH_TABLE_SIZE] =
34         { [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
35 static struct hlist_head module_table2[DEBUG_HASH_TABLE_SIZE] =
36         { [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
37 static DECLARE_MUTEX(debug_list_mutex);
38
39 /* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
40  * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
41  * use independent hash functions, to reduce the chance of false positives.
42  */
43 long long dynamic_printk_enabled;
44 EXPORT_SYMBOL_GPL(dynamic_printk_enabled);
45 long long dynamic_printk_enabled2;
46 EXPORT_SYMBOL_GPL(dynamic_printk_enabled2);
47
48 /* returns the debug module pointer. */
49 static struct debug_name *find_debug_module(char *module_name)
50 {
51         int i;
52         struct hlist_head *head;
53         struct hlist_node *node;
54         struct debug_name *element;
55
56         element = NULL;
57         for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
58                 head = &module_table[i];
59                 hlist_for_each_entry_rcu(element, node, head, hlist)
60                         if (!strcmp(element->name, module_name))
61                                 return element;
62         }
63         return NULL;
64 }
65
66 /* returns the debug module pointer. */
67 static struct debug_name *find_debug_module_hash(char *module_name, int hash)
68 {
69         struct hlist_head *head;
70         struct hlist_node *node;
71         struct debug_name *element;
72
73         element = NULL;
74         head = &module_table[hash];
75         hlist_for_each_entry_rcu(element, node, head, hlist)
76                 if (!strcmp(element->name, module_name))
77                         return element;
78         return NULL;
79 }
80
81 /* caller must hold mutex*/
82 static int __add_debug_module(char *mod_name, int hash, int hash2)
83 {
84         struct debug_name *new;
85         char *module_name;
86         int ret = 0;
87
88         if (find_debug_module(mod_name)) {
89                 ret = -EINVAL;
90                 goto out;
91         }
92         module_name = kmalloc(strlen(mod_name) + 1, GFP_KERNEL);
93         if (!module_name) {
94                 ret = -ENOMEM;
95                 goto out;
96         }
97         module_name = strcpy(module_name, mod_name);
98         module_name[strlen(mod_name)] = '\0';
99         new = kzalloc(sizeof(struct debug_name), GFP_KERNEL);
100         if (!new) {
101                 kfree(module_name);
102                 ret = -ENOMEM;
103                 goto out;
104         }
105         INIT_HLIST_NODE(&new->hlist);
106         INIT_HLIST_NODE(&new->hlist2);
107         new->name = module_name;
108         new->hash1 = hash;
109         new->hash2 = hash2;
110         hlist_add_head_rcu(&new->hlist, &module_table[hash]);
111         hlist_add_head_rcu(&new->hlist2, &module_table2[hash2]);
112         nr_entries++;
113 out:
114         return ret;
115 }
116
117 int unregister_dynamic_debug_module(char *mod_name)
118 {
119         struct debug_name *element;
120         int ret = 0;
121
122         down(&debug_list_mutex);
123         element = find_debug_module(mod_name);
124         if (!element) {
125                 ret = -EINVAL;
126                 goto out;
127         }
128         hlist_del_rcu(&element->hlist);
129         hlist_del_rcu(&element->hlist2);
130         synchronize_rcu();
131         kfree(element->name);
132         if (element->enable)
133                 num_enabled--;
134         kfree(element);
135         nr_entries--;
136 out:
137         up(&debug_list_mutex);
138         return ret;
139 }
140 EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
141
142 int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
143                                         char *flags, int hash, int hash2)
144 {
145         struct debug_name *elem;
146         int ret = 0;
147
148         down(&debug_list_mutex);
149         elem = find_debug_module(mod_name);
150         if (!elem) {
151                 if (__add_debug_module(mod_name, hash, hash2))
152                         goto out;
153                 elem = find_debug_module(mod_name);
154                 if (dynamic_enabled == DYNAMIC_ENABLED_ALL &&
155                                 !strcmp(mod_name, share_name)) {
156                         elem->enable = true;
157                         num_enabled++;
158                 }
159         }
160         elem->type |= type;
161 out:
162         up(&debug_list_mutex);
163         return ret;
164 }
165 EXPORT_SYMBOL_GPL(register_dynamic_debug_module);
166
167 int __dynamic_dbg_enabled_helper(char *mod_name, int type, int value, int hash)
168 {
169         struct debug_name *elem;
170         int ret = 0;
171
172         if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
173                 return 1;
174         rcu_read_lock();
175         elem = find_debug_module_hash(mod_name, hash);
176         if (elem && elem->enable)
177                 ret = 1;
178         rcu_read_unlock();
179         return ret;
180 }
181 EXPORT_SYMBOL_GPL(__dynamic_dbg_enabled_helper);
182
183 static void set_all(bool enable)
184 {
185         struct debug_name *e;
186         struct hlist_node *node;
187         int i;
188         long long enable_mask;
189
190         for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
191                 if (module_table[i].first != NULL) {
192                         hlist_for_each_entry(e, node, &module_table[i], hlist) {
193                                 e->enable = enable;
194                         }
195                 }
196         }
197         if (enable)
198                 enable_mask = ULLONG_MAX;
199         else
200                 enable_mask = 0;
201         dynamic_printk_enabled = enable_mask;
202         dynamic_printk_enabled2 = enable_mask;
203 }
204
205 static int disabled_hash(int i, bool first_table)
206 {
207         struct debug_name *e;
208         struct hlist_node *node;
209
210         if (first_table) {
211                 hlist_for_each_entry(e, node, &module_table[i], hlist) {
212                         if (e->enable)
213                                 return 0;
214                 }
215         } else {
216                 hlist_for_each_entry(e, node, &module_table2[i], hlist2) {
217                         if (e->enable)
218                                 return 0;
219                 }
220         }
221         return 1;
222 }
223
224 static ssize_t pr_debug_write(struct file *file, const char __user *buf,
225                                 size_t length, loff_t *ppos)
226 {
227         char *buffer, *s, *value_str, *setting_str;
228         int err, value;
229         struct debug_name *elem = NULL;
230         int all = 0;
231
232         if (length > PAGE_SIZE || length < 0)
233                 return -EINVAL;
234
235         buffer = (char *)__get_free_page(GFP_KERNEL);
236         if (!buffer)
237                 return -ENOMEM;
238
239         err = -EFAULT;
240         if (copy_from_user(buffer, buf, length))
241                 goto out;
242
243         err = -EINVAL;
244         if (length < PAGE_SIZE)
245                 buffer[length] = '\0';
246         else if (buffer[PAGE_SIZE-1])
247                 goto out;
248
249         err = -EINVAL;
250         down(&debug_list_mutex);
251
252         if (strncmp("set", buffer, 3))
253                 goto out_up;
254         s = buffer + 3;
255         setting_str = strsep(&s, "=");
256         if (s == NULL)
257                 goto out_up;
258         setting_str = strstrip(setting_str);
259         value_str = strsep(&s, " ");
260         if (s == NULL)
261                 goto out_up;
262         s = strstrip(s);
263         if (!strncmp(s, "all", 3))
264                 all = 1;
265         else
266                 elem = find_debug_module(s);
267         if (!strncmp(setting_str, "enable", 6)) {
268                 value = !!simple_strtol(value_str, NULL, 10);
269                 if (all) {
270                         if (value) {
271                                 set_all(true);
272                                 num_enabled = nr_entries;
273                                 dynamic_enabled = DYNAMIC_ENABLED_ALL;
274                         } else {
275                                 set_all(false);
276                                 num_enabled = 0;
277                                 dynamic_enabled = DYNAMIC_ENABLED_NONE;
278                         }
279                         err = 0;
280                 } else if (elem) {
281                         if (value && (elem->enable == 0)) {
282                                 dynamic_printk_enabled |= (1LL << elem->hash1);
283                                 dynamic_printk_enabled2 |= (1LL << elem->hash2);
284                                 elem->enable = 1;
285                                 num_enabled++;
286                                 dynamic_enabled = DYNAMIC_ENABLED_SOME;
287                                 err = 0;
288                                 printk(KERN_DEBUG
289                                         "debugging enabled for module %s\n",
290                                         elem->name);
291                         } else if (!value && (elem->enable == 1)) {
292                                 elem->enable = 0;
293                                 num_enabled--;
294                                 if (disabled_hash(elem->hash1, true))
295                                         dynamic_printk_enabled &=
296                                                         ~(1LL << elem->hash1);
297                                 if (disabled_hash(elem->hash2, false))
298                                         dynamic_printk_enabled2 &=
299                                                         ~(1LL << elem->hash2);
300                                 if (num_enabled)
301                                         dynamic_enabled = DYNAMIC_ENABLED_SOME;
302                                 else
303                                         dynamic_enabled = DYNAMIC_ENABLED_NONE;
304                                 err = 0;
305                                 printk(KERN_DEBUG
306                                         "debugging disabled for module %s\n",
307                                         elem->name);
308                         }
309                 }
310         }
311         if (!err)
312                 err = length;
313 out_up:
314         up(&debug_list_mutex);
315 out:
316         free_page((unsigned long)buffer);
317         return err;
318 }
319
320 static void *pr_debug_seq_start(struct seq_file *f, loff_t *pos)
321 {
322         return (*pos < DEBUG_HASH_TABLE_SIZE) ? pos : NULL;
323 }
324
325 static void *pr_debug_seq_next(struct seq_file *s, void *v, loff_t *pos)
326 {
327         (*pos)++;
328         if (*pos >= DEBUG_HASH_TABLE_SIZE)
329                 return NULL;
330         return pos;
331 }
332
333 static void pr_debug_seq_stop(struct seq_file *s, void *v)
334 {
335         /* Nothing to do */
336 }
337
338 static int pr_debug_seq_show(struct seq_file *s, void *v)
339 {
340         struct hlist_head *head;
341         struct hlist_node *node;
342         struct debug_name *elem;
343         unsigned int i = *(loff_t *) v;
344
345         rcu_read_lock();
346         head = &module_table[i];
347         hlist_for_each_entry_rcu(elem, node, head, hlist) {
348                 seq_printf(s, "%s enabled=%d", elem->name, elem->enable);
349                 seq_printf(s, "\n");
350         }
351         rcu_read_unlock();
352         return 0;
353 }
354
355 static struct seq_operations pr_debug_seq_ops = {
356         .start = pr_debug_seq_start,
357         .next  = pr_debug_seq_next,
358         .stop  = pr_debug_seq_stop,
359         .show  = pr_debug_seq_show
360 };
361
362 static int pr_debug_open(struct inode *inode, struct file *filp)
363 {
364         return seq_open(filp, &pr_debug_seq_ops);
365 }
366
367 static const struct file_operations pr_debug_operations = {
368         .open           = pr_debug_open,
369         .read           = seq_read,
370         .write          = pr_debug_write,
371         .llseek         = seq_lseek,
372         .release        = seq_release,
373 };
374
375 static int __init dynamic_printk_init(void)
376 {
377         struct dentry *dir, *file;
378         struct mod_debug *iter;
379         unsigned long value;
380
381         dir = debugfs_create_dir("dynamic_printk", NULL);
382         if (!dir)
383                 return -ENOMEM;
384         file = debugfs_create_file("modules", 0644, dir, NULL,
385                                         &pr_debug_operations);
386         if (!file) {
387                 debugfs_remove(dir);
388                 return -ENOMEM;
389         }
390         for (value = (unsigned long)__start___verbose;
391                 value < (unsigned long)__stop___verbose;
392                 value += sizeof(struct mod_debug)) {
393                         iter = (struct mod_debug *)value;
394                         register_dynamic_debug_module(iter->modname,
395                                 iter->type,
396                                 iter->logical_modname,
397                                 iter->flag_names, iter->hash, iter->hash2);
398         }
399         if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
400                 set_all(true);
401         return 0;
402 }
403 module_init(dynamic_printk_init);
404 /* may want to move this earlier so we can get traces as early as possible */
405
406 static int __init dynamic_printk_setup(char *str)
407 {
408         if (str)
409                 return -ENOENT;
410         dynamic_enabled = DYNAMIC_ENABLED_ALL;
411         return 0;
412 }
413 /* Use early_param(), so we can get debug output as early as possible */
414 early_param("dynamic_printk", dynamic_printk_setup);