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|
/*
* lib/dynamic_printk.c
*
* make pr_debug()/dev_dbg() calls runtime configurable based upon their
* their source module.
*
* Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
extern struct mod_debug __start___verbose[];
extern struct mod_debug __stop___verbose[];
struct debug_name {
struct hlist_node hlist;
struct hlist_node hlist2;
int hash1;
int hash2;
char *name;
int enable;
int type;
};
static int nr_entries;
static int num_enabled;
int dynamic_enabled = DYNAMIC_ENABLED_NONE;
static struct hlist_head module_table[DEBUG_HASH_TABLE_SIZE] =
{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
static struct hlist_head module_table2[DEBUG_HASH_TABLE_SIZE] =
{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
static DECLARE_MUTEX(debug_list_mutex);
/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
* use independent hash functions, to reduce the chance of false positives.
*/
long long dynamic_printk_enabled;
EXPORT_SYMBOL_GPL(dynamic_printk_enabled);
long long dynamic_printk_enabled2;
EXPORT_SYMBOL_GPL(dynamic_printk_enabled2);
/* returns the debug module pointer. */
static struct debug_name *find_debug_module(char *module_name)
{
int i;
struct hlist_head *head;
struct hlist_node *node;
struct debug_name *element;
element = NULL;
for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
head = &module_table[i];
hlist_for_each_entry_rcu(element, node, head, hlist)
if (!strcmp(element->name, module_name))
return element;
}
return NULL;
}
/* returns the debug module pointer. */
static struct debug_name *find_debug_module_hash(char *module_name, int hash)
{
struct hlist_head *head;
struct hlist_node *node;
struct debug_name *element;
element = NULL;
head = &module_table[hash];
hlist_for_each_entry_rcu(element, node, head, hlist)
if (!strcmp(element->name, module_name))
return element;
return NULL;
}
/* caller must hold mutex*/
static int __add_debug_module(char *mod_name, int hash, int hash2)
{
struct debug_name *new;
char *module_name;
int ret = 0;
if (find_debug_module(mod_name)) {
ret = -EINVAL;
goto out;
}
module_name = kmalloc(strlen(mod_name) + 1, GFP_KERNEL);
if (!module_name) {
ret = -ENOMEM;
goto out;
}
module_name = strcpy(module_name, mod_name);
module_name[strlen(mod_name)] = '\0';
new = kzalloc(sizeof(struct debug_name), GFP_KERNEL);
if (!new) {
kfree(module_name);
ret = -ENOMEM;
goto out;
}
INIT_HLIST_NODE(&new->hlist);
INIT_HLIST_NODE(&new->hlist2);
new->name = module_name;
new->hash1 = hash;
new->hash2 = hash2;
hlist_add_head_rcu(&new->hlist, &module_table[hash]);
hlist_add_head_rcu(&new->hlist2, &module_table2[hash2]);
nr_entries++;
out:
return ret;
}
int unregister_dynamic_debug_module(char *mod_name)
{
struct debug_name *element;
int ret = 0;
down(&debug_list_mutex);
element = find_debug_module(mod_name);
if (!element) {
ret = -EINVAL;
goto out;
}
hlist_del_rcu(&element->hlist);
hlist_del_rcu(&element->hlist2);
synchronize_rcu();
kfree(element->name);
if (element->enable)
num_enabled--;
kfree(element);
nr_entries--;
out:
up(&debug_list_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
char *flags, int hash, int hash2)
{
struct debug_name *elem;
int ret = 0;
down(&debug_list_mutex);
elem = find_debug_module(mod_name);
if (!elem) {
if (__add_debug_module(mod_name, hash, hash2))
goto out;
elem = find_debug_module(mod_name);
if (dynamic_enabled == DYNAMIC_ENABLED_ALL &&
!strcmp(mod_name, share_name)) {
elem->enable = true;
num_enabled++;
}
}
elem->type |= type;
out:
up(&debug_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(register_dynamic_debug_module);
int __dynamic_dbg_enabled_helper(char *mod_name, int type, int value, int hash)
{
struct debug_name *elem;
int ret = 0;
if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
return 1;
rcu_read_lock();
elem = find_debug_module_hash(mod_name, hash);
if (elem && elem->enable)
ret = 1;
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(__dynamic_dbg_enabled_helper);
static void set_all(bool enable)
{
struct debug_name *e;
struct hlist_node *node;
int i;
long long enable_mask;
for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
if (module_table[i].first != NULL) {
hlist_for_each_entry(e, node, &module_table[i], hlist) {
e->enable = enable;
}
}
}
if (enable)
enable_mask = ULLONG_MAX;
else
enable_mask = 0;
dynamic_printk_enabled = enable_mask;
dynamic_printk_enabled2 = enable_mask;
}
static int disabled_hash(int i, bool first_table)
{
struct debug_name *e;
struct hlist_node *node;
if (first_table) {
hlist_for_each_entry(e, node, &module_table[i], hlist) {
if (e->enable)
return 0;
}
} else {
hlist_for_each_entry(e, node, &module_table2[i], hlist2) {
if (e->enable)
return 0;
}
}
return 1;
}
static ssize_t pr_debug_write(struct file *file, const char __user *buf,
size_t length, loff_t *ppos)
{
char *buffer, *s, *value_str, *setting_str;
int err, value;
struct debug_name *elem = NULL;
int all = 0;
if (length > PAGE_SIZE || length < 0)
return -EINVAL;
buffer = (char *)__get_free_page(GFP_KERNEL);
if (!buffer)
return -ENOMEM;
err = -EFAULT;
if (copy_from_user(buffer, buf, length))
goto out;
err = -EINVAL;
if (length < PAGE_SIZE)
buffer[length] = '\0';
else if (buffer[PAGE_SIZE-1])
goto out;
err = -EINVAL;
down(&debug_list_mutex);
if (strncmp("set", buffer, 3))
|