+++ /dev/null
-/*
- * (C) Copyright 2009 -
- * Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
- *
- * LTTng kprobes integration module.
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#include <linux/module.h>
-#include <linux/kprobes.h>
-#include <linux/marker.h>
-#include <linux/mutex.h>
-#include <linux/jhash.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-#include <linux/debugfs.h>
-#include <linux/kallsyms.h>
-
-#include "ltt-type-serializer.h"
-#include "ltt-tracer.h"
-
-#define LTT_KPROBES_DIR "kprobes"
-#define LTT_KPROBES_ENABLE "enable"
-#define LTT_KPROBES_DISABLE "disable"
-#define LTT_KPROBES_LIST "list"
-
-/* Active LTTng kprobes hash table */
-static DEFINE_MUTEX(ltt_kprobes_mutex);
-
-#define LTT_KPROBE_HASH_BITS 6
-#define LTT_KPROBE_TABLE_SIZE (1 << LTT_KPROBE_HASH_BITS)
-static struct hlist_head ltt_kprobe_table[LTT_KPROBE_TABLE_SIZE];
-
-struct kprobe_entry {
- struct hlist_node hlist;
- struct kprobe kp;
- char key[0];
-};
-
-static struct dentry *ltt_kprobes_dir,
- *ltt_kprobes_enable_dentry,
- *ltt_kprobes_disable_dentry,
- *ltt_kprobes_list_dentry;
-
-static int module_exit;
-
-
-static void trace_kprobe_table_entry(void *call_data, struct kprobe_entry *e)
-{
- unsigned long addr;
- char *namebuf = (char *)__get_free_page(GFP_KERNEL);
-
- if (e->kp.addr) {
- sprint_symbol(namebuf, (unsigned long)e->kp.addr);
- addr = (unsigned long)e->kp.addr;
- } else {
- strncpy(namebuf, e->kp.symbol_name, PAGE_SIZE - 1);
- /* TODO : add offset */
- addr = kallsyms_lookup_name(namebuf);
- }
- if (addr)
- __trace_mark(0, kprobe_state, kprobe_table, call_data,
- "ip 0x%lX symbol %s", addr, namebuf);
- free_page((unsigned long)namebuf);
-}
-
-DEFINE_MARKER(kernel, kprobe, "ip %lX");
-
-static int ltt_kprobe_handler_pre(struct kprobe *p, struct pt_regs *regs)
-{
- struct marker *marker;
- unsigned long data;
-
- data = (unsigned long)p->addr;
- marker = &GET_MARKER(kernel, kprobe);
- ltt_specialized_trace(marker, marker->single.probe_private,
- &data, sizeof(data), sizeof(data));
- return 0;
-}
-
-static int ltt_register_kprobe(const char *key)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe_entry *e = NULL;
- char *symbol_name = NULL;
- unsigned long addr;
- unsigned int offset = 0;
- u32 hash;
- size_t key_len = strlen(key) + 1;
- int ret;
-
- if (key_len == 1)
- return -ENOENT; /* only \0 */
-
- if (sscanf(key, "%li", &addr) != 1)
- addr = 0;
-
- if (!addr) {
- const char *symbol_end = NULL;
- unsigned int symbol_len; /* includes final \0 */
-
- symbol_end = strchr(key, ' ');
- if (symbol_end)
- symbol_len = symbol_end - key + 1;
- else
- symbol_len = key_len;
- symbol_name = kmalloc(symbol_len, GFP_KERNEL);
- if (!symbol_name) {
- ret = -ENOMEM;
- goto error;
- }
- memcpy(symbol_name, key, symbol_len - 1);
- symbol_name[symbol_len-1] = '\0';
- if (symbol_end) {
- symbol_end++; /* start of offset */
- if (sscanf(symbol_end, "%i", &offset) != 1)
- offset = 0;
- }
- }
-
- hash = jhash(key, key_len-1, 0);
- head = <t_kprobe_table[hash & ((1 << LTT_KPROBE_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(key, e->key)) {
- printk(KERN_NOTICE "Kprobe %s busy\n", key);
- ret = -EBUSY;
- goto error;
- }
- }
- /*
- * Using kzalloc here to allocate a variable length element. Could
- * cause some memory fragmentation if overused.
- */
- e = kzalloc(sizeof(struct kprobe_entry) + key_len, GFP_KERNEL);
- if (!e) {
- ret = -ENOMEM;
- goto error;
- }
- memcpy(e->key, key, key_len);
- hlist_add_head(&e->hlist, head);
- e->kp.pre_handler = ltt_kprobe_handler_pre;
- e->kp.symbol_name = symbol_name;
- e->kp.offset = offset;
- e->kp.addr = (void *)addr;
- ret = register_kprobe(&e->kp);
- if (ret < 0)
- goto error_list_del;
- trace_kprobe_table_entry(NULL, e);
- return 0;
-
-error_list_del:
- hlist_del(&e->hlist);
-error:
- kfree(symbol_name);
- kfree(e);
- return ret;
-}
-
-static int ltt_unregister_kprobe(const char *key)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe_entry *e;
- int found = 0;
- size_t key_len = strlen(key) + 1;
- u32 hash;
-
- hash = jhash(key, key_len-1, 0);
- head = <t_kprobe_table[hash & ((1 << LTT_KPROBE_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(key, e->key)) {
- found = 1;
- break;
- }
- }
- if (!found)
- return -ENOENT;
- hlist_del(&e->hlist);
- unregister_kprobe(&e->kp);
- kfree(e->kp.symbol_name);
- kfree(e);
- return 0;
-}
-
-static void ltt_unregister_all_kprobes(void)
-{
- struct kprobe_entry *e;
- struct hlist_head *head;
- struct hlist_node *node, *tmp;
- unsigned int i;
-
- for (i = 0; i < LTT_KPROBE_TABLE_SIZE; i++) {
- head = <t_kprobe_table[i];
- hlist_for_each_entry_safe(e, node, tmp, head, hlist) {
- hlist_del(&e->hlist);
- unregister_kprobe(&e->kp);
- kfree(e->kp.symbol_name);
- kfree(e);
- }
- }
-}
-
-/*
- * Allows to specify either
- * - symbol
- * - symbol offset
- * - address
- */
-static ssize_t enable_op_write(struct file *file,
- const char __user *user_buf, size_t count, loff_t *ppos)
-{
- int err, buf_size;
- char *end;
- char *buf = (char *)__get_free_page(GFP_KERNEL);
-
- mutex_lock(<t_kprobes_mutex);
- if (module_exit) {
- err = -EPERM;
- goto error;
- }
-
- buf_size = min_t(size_t, count, PAGE_SIZE - 1);
- err = copy_from_user(buf, user_buf, buf_size);
- if (err)
- goto error;
- buf[buf_size] = '\0';
- end = strchr(buf, '\n');
- if (end)
- *end = '\0';
- err = ltt_register_kprobe(buf);
- if (err)
- goto error;
-
- mutex_unlock(<t_kprobes_mutex);
- free_page((unsigned long)buf);
- return count;
-error:
- mutex_unlock(<t_kprobes_mutex);
- free_page((unsigned long)buf);
- return err;
-}
-
-static const struct file_operations ltt_kprobes_enable = {
- .write = enable_op_write,
-};
-
-static ssize_t disable_op_write(struct file *file,
- const char __user *user_buf, size_t count, loff_t *ppos)
-{
- int err, buf_size;
- char *end;
- char *buf = (char *)__get_free_page(GFP_KERNEL);
-
- mutex_lock(<t_kprobes_mutex);
- if (module_exit)
- goto end;
-
- buf_size = min_t(size_t, count, PAGE_SIZE - 1);
- err = copy_from_user(buf, user_buf, buf_size);
- if (err)
- goto error;
- buf[buf_size] = '\0';
- end = strchr(buf, '\n');
- if (end)
- *end = '\0';
- err = ltt_unregister_kprobe(buf);
- if (err)
- goto error;
-end:
- mutex_unlock(<t_kprobes_mutex);
- free_page((unsigned long)buf);
- return count;
-error:
- mutex_unlock(<t_kprobes_mutex);
- free_page((unsigned long)buf);
- return err;
-}
-
-static const struct file_operations ltt_kprobes_disable = {
- .write = disable_op_write,
-};
-
-/*
- * This seqfile read is not perfectly safe, as a kprobe could be removed from
- * the hash table between two reads. This will result in an incomplete output.
- */
-static struct kprobe_entry *ltt_find_next_kprobe(struct kprobe_entry *prev)
-{
- struct kprobe_entry *e;
- struct hlist_head *head;
- struct hlist_node *node;
- unsigned int i;
- int found = 0;
-
- if (prev == (void *)-1UL)
- return NULL;
-
- if (!prev)
- found = 1;
-
- for (i = 0; i < LTT_KPROBE_TABLE_SIZE; i++) {
- head = <t_kprobe_table[i];
- hlist_for_each_entry(e, node, head, hlist) {
- if (found)
- return e;
- if (e == prev)
- found = 1;
- }
- }
- return NULL;
-}
-
-static void *lk_next(struct seq_file *m, void *p, loff_t *pos)
-{
- m->private = ltt_find_next_kprobe(m->private);
- if (!m->private) {
- m->private = (void *)-1UL;
- return NULL;
- }
- return m->private;
-}
-
-static void *lk_start(struct seq_file *m, loff_t *pos)
-{
- mutex_lock(<t_kprobes_mutex);
- if (!*pos)
- m->private = NULL;
- m->private = ltt_find_next_kprobe(m->private);
- if (!m->private) {
- m->private = (void *)-1UL;
- return NULL;
- }
- return m->private;
-}
-
-static void lk_stop(struct seq_file *m, void *p)
-{
- mutex_unlock(<t_kprobes_mutex);
-}
-
-static int lk_show(struct seq_file *m, void *p)
-{
- struct kprobe_entry *e = m->private;
- seq_printf(m, "%s\n", e->key);
- return 0;
-}
-
-static const struct seq_operations ltt_kprobes_list_op = {
- .start = lk_start,
- .next = lk_next,
- .stop = lk_stop,
- .show = lk_show,
-};
-
-static int ltt_kprobes_list_open(struct inode *inode, struct file *file)
-{
- int ret;
-
- ret = seq_open(file, <t_kprobes_list_op);
- if (ret == 0)
- ((struct seq_file *)file->private_data)->private = NULL;
- return ret;
-}
-
-static int ltt_kprobes_list_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = file->private_data;
-
- seq->private = NULL;
- return seq_release(inode, file);
-}
-
-static const struct file_operations ltt_kprobes_list = {
- .open = ltt_kprobes_list_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = ltt_kprobes_list_release,
-};
-
-/*
- * kprobes table dump. Callback invoked by ltt-statedump. ltt-statedump must
- * take a reference to this module before calling this callback.
- */
-void ltt_dump_kprobes_table(void *call_data)
-{
- struct kprobe_entry *e;
- struct hlist_head *head;
- struct hlist_node *node;
- unsigned int i;
-
- for (i = 0; i < LTT_KPROBE_TABLE_SIZE; i++) {
- head = <t_kprobe_table[i];
- hlist_for_each_entry(e, node, head, hlist)
- trace_kprobe_table_entry(call_data, e);
- }
-}
-EXPORT_SYMBOL_GPL(ltt_dump_kprobes_table);
-
-static int __init ltt_kprobes_init(void)
-{
- struct dentry *ltt_root_dentry;
- int ret = 0;
-
- printk(KERN_INFO "LTT : ltt-kprobes init\n");
- mutex_lock(<t_kprobes_mutex);
-
- ltt_root_dentry = get_ltt_root();
- if (!ltt_root_dentry) {
- ret = -ENOENT;
- goto err_no_root;
- }
-
- ltt_kprobes_dir = debugfs_create_dir(LTT_KPROBES_DIR, ltt_root_dentry);
- if (!ltt_kprobes_dir) {
- printk(KERN_ERR
- "ltt_kprobes_init: failed to create dir %s\n",
- LTT_KPROBES_DIR);
- ret = -ENOMEM;
- goto err_no_dir;
- }
-
- ltt_kprobes_enable_dentry = debugfs_create_file(LTT_KPROBES_ENABLE,
- S_IWUSR,
- ltt_kprobes_dir, NULL,
- <t_kprobes_enable);
- if (IS_ERR(ltt_kprobes_enable_dentry) || !ltt_kprobes_enable_dentry) {
- printk(KERN_ERR
- "ltt_kprobes_init: failed to create file %s\n",
- LTT_KPROBES_ENABLE);
- ret = -ENOMEM;
- goto err_no_enable;
- }
-
- ltt_kprobes_disable_dentry = debugfs_create_file(LTT_KPROBES_DISABLE,
- S_IWUSR,
- ltt_kprobes_dir, NULL,
- <t_kprobes_disable);
- if (IS_ERR(ltt_kprobes_disable_dentry) || !ltt_kprobes_disable_dentry) {
- printk(KERN_ERR
- "ltt_kprobes_init: failed to create file %s\n",
- LTT_KPROBES_DISABLE);
- ret = -ENOMEM;
- goto err_no_disable;
- }
-
- ltt_kprobes_list_dentry = debugfs_create_file(LTT_KPROBES_LIST,
- S_IWUSR, ltt_kprobes_dir,
- NULL, <t_kprobes_list);
- if (IS_ERR(ltt_kprobes_list_dentry) || !ltt_kprobes_list_dentry) {
- printk(KERN_ERR
- "ltt_kprobes_init: failed to create file %s\n",
- LTT_KPROBES_LIST);
- ret = -ENOMEM;
- goto err_no_list;
- }
- ltt_statedump_register_kprobes_dump(ltt_dump_kprobes_table);
-
- mutex_unlock(<t_kprobes_mutex);
- return ret;
-
-err_no_list:
- debugfs_remove(ltt_kprobes_disable_dentry);
-err_no_disable:
- debugfs_remove(ltt_kprobes_enable_dentry);
-err_no_enable:
- debugfs_remove(ltt_kprobes_dir);
-err_no_dir:
-err_no_root:
- mutex_unlock(<t_kprobes_mutex);
- return ret;
-}
-module_init(ltt_kprobes_init);
-
-static void __exit ltt_kprobes_exit(void)
-{
- printk(KERN_INFO "LTT : ltt-kprobes exit\n");
- mutex_lock(<t_kprobes_mutex);
- module_exit = 1;
- ltt_statedump_unregister_kprobes_dump(ltt_dump_kprobes_table);
- debugfs_remove(ltt_kprobes_list_dentry);
- debugfs_remove(ltt_kprobes_disable_dentry);
- debugfs_remove(ltt_kprobes_enable_dentry);
- debugfs_remove(ltt_kprobes_dir);
- ltt_unregister_all_kprobes();
- mutex_unlock(<t_kprobes_mutex);
-}
-module_exit(ltt_kprobes_exit);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");
projects / lttng-modules.git / blobdiff