text: /*
   * trace_events_trigger - trace event triggers
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
   */
  
  #include <linux/module.h>
  #include <linux/ctype.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  #include <linux/rculist.h>
  
  #include "trace.h"
  
  static LIST_HEAD(trigger_commands);
  static DEFINE_MUTEX(trigger_cmd_mutex);
  
  void trigger_data_free(struct event_trigger_data *data)
  {
  	if (data->cmd_ops->set_filter)
  		data->cmd_ops->set_filter(NULL, data, NULL);
  
  	synchronize_sched(); /* make sure current triggers exit before free */
  	kfree(data);
  }
  
  /**
   * event_triggers_call - Call triggers associated with a trace event
   * @file: The trace_event_file associated with the event
   * @rec: The trace entry for the event, NULL for unconditional invocation
   *
   * For each trigger associated with an event, invoke the trigger
   * function registered with the associated trigger command.  If rec is
   * non-NULL, it means that the trigger requires further processing and
   * shouldn't be unconditionally invoked.  If rec is non-NULL and the
   * trigger has a filter associated with it, rec will checked against
   * the filter and if the record matches the trigger will be invoked.
   * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
   * in any case until the current event is written, the trigger
   * function isn't invoked but the bit associated with the deferred
   * trigger is set in the return value.
   *
   * Returns an enum event_trigger_type value containing a set bit for
   * any trigger that should be deferred, ETT_NONE if nothing to defer.
   *
   * Called from tracepoint handlers (with rcu_read_lock_sched() held).
   *
   * Return: an enum event_trigger_type value containing a set bit for
   * any trigger that should be deferred, ETT_NONE if nothing to defer.
   */
  enum event_trigger_type
  event_triggers_call(struct trace_event_file *file, void *rec,
  		    struct ring_buffer_event *event)
  {
  	struct event_trigger_data *data;
  	enum event_trigger_type tt = ETT_NONE;
  	struct event_filter *filter;
  
  	if (list_empty(&file->triggers))
  		return tt;
  
  	list_for_each_entry_rcu(data, &file->triggers, list) {
  		if (data->paused)
  			continue;
  		if (!rec) {
  			data->ops->func(data, rec, event);
  			continue;
  		}
  		filter = rcu_dereference_sched(data->filter);
  		if (filter && !filter_match_preds(filter, rec))
  			continue;
  		if (event_command_post_trigger(data->cmd_ops)) {
  			tt |= data->cmd_ops->trigger_type;
  			continue;
  		}
  		data->ops->func(data, rec, event);
  	}
  	return tt;
  }
  EXPORT_SYMBOL_GPL(event_triggers_call);
  
  /**
   * event_triggers_post_call - Call 'post_triggers' for a trace event
   * @file: The trace_event_file associated with the event
   * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
   *
   * For each trigger associated with an event, invoke the trigger
   * function registered with the associated trigger command, if the
   * corresponding bit is set in the tt enum passed into this function.
   * See @event_triggers_call for details on how those bits are set.
   *
   * Called from tracepoint handlers (with rcu_read_lock_sched() held).
   */
  void
  event_triggers_post_call(struct trace_event_file *file,
  			 enum event_trigger_type tt)
  {
  	struct event_trigger_data *data;
  
  	list_for_each_entry_rcu(data, &file->triggers, list) {
  		if (data->paused)
  			continue;
  		if (data->cmd_ops->trigger_type & tt)
  			data->ops->func(data, NULL, NULL);
  	}
  }
  EXPORT_SYMBOL_GPL(event_triggers_post_call);
  
  #define SHOW_AVAILABLE_TRIGGERS	(void *)(1UL)
  
  static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
  {
  	struct trace_event_file *event_file = event_file_data(m->private);
  
  	if (t == SHOW_AVAILABLE_TRIGGERS)
  		return NULL;
  
  	return seq_list_next(t, &event_file->triggers, pos);
  }
  
  static void *trigger_start(struct seq_file *m, loff_t *pos)
  {
  	struct trace_event_file *event_file;
  
  	/* ->stop() is called even if ->start() fails */
  	mutex_lock(&event_mutex);
  	event_file = event_file_data(m->private);
  	if (unlikely(!event_file))
  		return ERR_PTR(-ENODEV);
  
  	if (list_empty(&event_file->triggers))
  		return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
  
  	return seq_list_start(&event_file->triggers, *pos);
  }
  
  static void trigger_stop(struct seq_file *m, void *t)
  {
  	mutex_unlock(&event_mutex);
  }
  
  static int trigger_show(struct seq_file *m, void *v)
  {
  	struct event_trigger_data *data;
  	struct event_command *p;
  
  	if (v == SHOW_AVAILABLE_TRIGGERS) {
  		seq_puts(m, "# Available triggers:\n");
  		seq_putc(m, '#');
  		mutex_lock(&trigger_cmd_mutex);
  		list_for_each_entry_reverse(p, &trigger_commands, list)
  			seq_printf(m, " %s", p->name);
  		seq_putc(m, '\n');
  		mutex_unlock(&trigger_cmd_mutex);
  		return 0;
  	}
  
  	data = list_entry(v, struct event_trigger_data, list);
  	data->ops->print(m, data->ops, data);
  
  	return 0;
  }
  
  static const struct seq_operations event_triggers_seq_ops = {
  	.start = trigger_start,
  	.next = trigger_next,
  	.stop = trigger_stop,
  	.show = trigger_show,
  };
  
  static int event_trigger_regex_open(struct inode *inode, struct file *file)
  {
  	int ret = 0;
  
  	mutex_lock(&event_mutex);
  
  	if (unlikely(!event_file_data(file))) {
  		mutex_unlock(&event_mutex);
  		return -ENODEV;
  	}
  
  	if ((file->f_mode & FMODE_WRITE) &&
  	    (file->f_flags & O_TRUNC)) {
  		struct trace_event_file *event_file;
  		struct event_command *p;
  
  		event_file = event_file_data(file);
  
  		list_for_each_entry(p, &trigger_commands, list) {
  			if (p->unreg_all)
  				p->unreg_all(event_file);
  		}
  	}
  
  	if (file->f_mode & FMODE_READ) {
  		ret = seq_open(file, &event_triggers_seq_ops);
  		if (!ret) {
  			struct seq_file *m = file->private_data;
  			m->private = file;
  		}
  	}
  
  	mutex_unlock(&event_mutex);
  
  	return ret;
  }
  
  static int trigger_process_regex(struct trace_event_file *file, char *buff)
  {
  	char *command, *next = buff;
  	struct event_command *p;
  	int ret = -EINVAL;
  
  	command = strsep(&next, ": \t");
  	command = (command[0] != '!') ? command : command + 1;
  
  	mutex_lock(&trigger_cmd_mutex);
  	list_for_each_entry(p, &trigger_commands, list) {
  		if (strcmp(p->name, command) == 0) {
  			ret = p->func(p, file, buff, command, next);
  			goto out_unlock;
  		}
  	}
   out_unlock:
  	mutex_unlock(&trigger_cmd_mutex);
  
  	return ret;
  }
  
  static ssize_t event_trigger_regex_write(struct file *file,
  					 const char __user *ubuf,
  					 size_t cnt, loff_t *ppos)
  {
  	struct trace_event_file *event_file;
  	ssize_t ret;
  	char *buf;
  
  	if (!cnt)
  		return 0;
  
  	if (cnt >= PAGE_SIZE)
  		return -EINVAL;
  
  	buf = memdup_user_nul(ubuf, cnt);
  	if (IS_ERR(buf))
  		return PTR_ERR(buf);
  
  	strim(buf);
  
  	mutex_lock(&event_mutex);
  	event_file = event_file_data(file);
  	if (unlikely(!event_file)) {
  		mutex_unlock(&event_mutex);
  		kfree(buf);
  		return -ENODEV;
  	}
  	ret = trigger_process_regex(event_file, buf);
  	mutex_unlock(&event_mutex);
  
  	kfree(buf);
  	if (ret < 0)
  		goto out;
  
  	*ppos += cnt;
  	ret = cnt;
   out:
  	return ret;
  }
  
  static int event_trigger_regex_release(struct inode *inode, struct file *file)
  {
  	mutex_lock(&event_mutex);
  
  	if (file->f_mode & FMODE_READ)
  		seq_release(inode, file);
  
  	mutex_unlock(&event_mutex);
  
  	return 0;
  }
  
  static ssize_t
  event_trigger_write(struct file *filp, const char __user *ubuf,
  		    size_t cnt, loff_t *ppos)
  {
  	return event_trigger_regex_write(filp, ubuf, cnt, ppos);
  }
  
  static int
  event_trigger_open(struct inode *inode, struct file *filp)
  {
  	return event_trigger_regex_open(inode, filp);
  }
  
  static int
  event_trigger_release(struct inode *inode, struct file *file)
  {
  	return event_trigger_regex_release(inode, file);
  }
  
  const struct file_operations event_trigger_fops = {
  	.open = event_trigger_open,
  	.read = seq_read,
  	.write = event_trigger_write,
  	.llseek = tracing_lseek,
  	.release = event_trigger_release,
  };
  
  /*
   * Currently we only register event commands from __init, so mark this
   * __init too.
   */
  __init int register_event_command(struct event_command *cmd)
  {
  	struct event_command *p;
  	int ret = 0;
  
  	mutex_lock(&trigger_cmd_mutex);
  	list_for_each_entry(p, &trigger_commands, list) {
  		if (strcmp(cmd->name, p->name) == 0) {
  			ret = -EBUSY;
  			goto out_unlock;
  		}
  	}
  	list_add(&cmd->list, &trigger_commands);
   out_unlock:
  	mutex_unlock(&trigger_cmd_mutex);
  
  	return ret;
  }
  
  /*
   * Currently we only unregister event commands from __init, so mark
   * this __init too.
   */
  __init int unregister_event_command(struct event_command *cmd)
  {
  	struct event_command *p, *n;
  	int ret = -ENODEV;
  
  	mutex_lock(&trigger_cmd_mutex);
  	list_for_each_entry_safe(p, n, &trigger_commands, list) {
  		if (strcmp(cmd->name, p->name) == 0) {
  			ret = 0;
  			list_del_init(&p->list);
  			goto out_unlock;
  		}
  	}
   out_unlock:
  	mutex_unlock(&trigger_cmd_mutex);
  
  	return ret;
  }
  
  /**
   * event_trigger_print - Generic event_trigger_ops @print implementation
   * @name: The name of the event trigger
   * @m: The seq_file being printed to
   * @data: Trigger-specific data
   * @filter_str: filter_str to print, if present
   *
   * Common implementation for event triggers to print themselves.
   *
   * Usually wrapped by a function that simply sets the @name of the
   * trigger command and then invokes this.
   *
   * Return: 0 on success, errno otherwise
   */
  static int
  event_trigger_print(const char *name, struct seq_file *m,
  		    void *data, char *filter_str)
  {
  	long count = (long)data;
  
  	seq_puts(m, name);
  
  	if (count == -1)
  		seq_puts(m, ":unlimited");
  	else
  		seq_printf(m, ":count=%ld", count);
  
  	if (filter_str)
  		seq_printf(m, " if %s\n", filter_str);
  	else
  		seq_putc(m, '\n');
  
  	return 0;
  }
  
  /**
   * event_trigger_init - Generic event_trigger_ops @init implementation
   * @ops: The trigger ops associated with the trigger
   * @data: Trigger-specific data
   *
   * Common implementation of event trigger initialization.
   *
   * Usually used directly as the @init method in event trigger
   * implementations.
   *
   * Return: 0 on success, errno otherwise
   */
  int event_trigger_init(struct event_trigger_ops *ops,
  		       struct event_trigger_data *data)
  {
  	data->ref++;
  	return 0;
  }
  
  /**
   * event_trigger_free - Generic event_trigger_ops @free implementation
   * @ops: The trigger ops associated with the trigger
   * @data: Trigger-specific data
   *
   * Common implementation of event trigger de-initialization.
   *
   * Usually used directly as the @free method in event trigger
   * implementations.
   */
  static void
  event_trigger_free(struct event_trigger_ops *ops,
  		   struct event_trigger_data *data)
  {
  	if (WARN_ON_ONCE(data->ref <= 0))
  		return;
  
  	data->ref--;
  	if (!data->ref)
  		trigger_data_free(data);
  }
  
  int trace_event_trigger_enable_disable(struct trace_event_file *file,
  				       int trigger_enable)
  {
  	int ret = 0;
  
  	if (trigger_enable) {
  		if (atomic_inc_return(&file->tm_ref) > 1)
  			return ret;
  		set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
  		ret = trace_event_enable_disable(file, 1, 1);
  	} else {
  		if (atomic_dec_return(&file->tm_ref) > 0)
  			return ret;
  		clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
  		ret = trace_event_enable_disable(file, 0, 1);
  	}
  
  	return ret;
  }
  
  /**
   * clear_event_triggers - Clear all triggers associated with a trace array
   * @tr: The trace array to clear
   *
   * For each trigger, the triggering event has its tm_ref decremented
   * via trace_event_trigger_enable_disable(), and any associated event
   * (in the case of enable/disable_event triggers) will have its sm_ref
   * decremented via free()->trace_event_enable_disable().  That
   * combination effectively reverses the soft-mode/trigger state added
   * by trigger registration.
   *
   * Must be called with event_mutex held.
   */
  void
  clear_event_triggers(struct trace_array *tr)
  {
  	struct trace_event_file *file;
  
  	list_for_each_entry(file, &tr->events, list) {
  		struct event_trigger_data *data, *n;
  		list_for_each_entry_safe(data, n, &file->triggers, list) {
  			trace_event_trigger_enable_disable(file, 0);
  			list_del_rcu(&data->list);
  			if (data->ops->free)
  				data->ops->free(data->ops, data);
  		}
  	}
  }
  
  /**
   * update_cond_flag - Set or reset the TRIGGER_COND bit
   * @file: The trace_event_file associated with the event
   *
   * If an event has triggers and any of those triggers has a filter or
   * a post_trigger, trigger invocation needs to be deferred until after
   * the current event has logged its data, and the event should have
   * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
   * cleared.
   */
  void update_cond_flag(struct trace_event_file *file)
  {
  	struct event_trigger_data *data;
  	bool set_cond = false;
  
  	list_for_each_entry_rcu(data, &file->triggers, list) {
  		if (data->filter || event_command_post_trigger(data->cmd_ops) ||
  		    event_command_needs_rec(data->cmd_ops)) {
  			set_cond = true;
  			break;
  		}
  	}
  
  	if (set_cond)
  		set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
  	else
  		clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
  }
  
  /**
   * register_trigger - Generic event_command @reg implementation
   * @glob: The raw string used to register the trigger
   * @ops: The trigger ops associated with the trigger
   * @data: Trigger-specific data to associate with the trigger
   * @file: The trace_event_file associated with the event
   *
   * Common implementation for event trigger registration.
   *
   * Usually used directly as the @reg method in event command
   * implementations.
   *
   * Return: 0 on success, errno otherwise
   */
  static int register_trigger(char *glob, struct event_trigger_ops *ops,
  			    struct event_trigger_data *data,
  			    struct trace_event_file *file)
  {
  	struct event_trigger_data *test;
  	int ret = 0;
  
  	list_for_each_entry_rcu(test, &file->triggers, list) {
  		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
  			ret = -EEXIST;
  			goto out;
  		}
  	}
  
  	if (data->ops->init) {
  		ret = data->ops->init(data->ops, data);
  		if (ret < 0)
  			goto out;
  	}
  
  	list_add_rcu(&data->list, &file->triggers);
  	ret++;
  
  	update_cond_flag(file);
  	if (trace_event_trigger_enable_disable(file, 1) < 0) {
  		list_del_rcu(&data->list);
  		update_cond_flag(file);
  		ret--;
  	}
  out:
  	return ret;
  }
  
  /**
   * unregister_trigger - Generic event_command @unreg implementation
   * @glob: The raw string used to register the trigger
   * @ops: The trigger ops associated with the trigger
   * @test: Trigger-specific data used to find the trigger to remove
   * @file: The trace_event_file associated with the event
   *
   * Common implementation for event trigger unregistration.
   *
   * Usually used directly as the @unreg method in event command
   * implementations.
   */
  void unregister_trigger(char *glob, struct event_trigger_ops *ops,
  			struct event_trigger_data *test,
  			struct trace_event_file *file)
  {
  	struct event_trigger_data *data;
  	bool unregistered = false;
  
  	list_for_each_entry_rcu(data, &file->triggers, list) {
  		if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
  			unregistered = true;
  			list_del_rcu(&data->list);
  			trace_event_trigger_enable_disable(file, 0);
  			update_cond_flag(file);
  			break;
  		}
  	}
  
  	if (unregistered && data->ops->free)
  		data->ops->free(data->ops, data);
  }
  
  /**
   * event_trigger_callback - Generic event_command @func implementation
   * @cmd_ops: The command ops, used for trigger registration
   * @file: The trace_event_file associated with the event
   * @glob: The raw string used to register the trigger
   * @cmd: The cmd portion of the string used to register the trigger
   * @param: The params portion of the string used to register the trigger
   *
   * Common implementation for event command parsing and trigger
   * instantiation.
   *
   * Usually used directly as the @func method in event command
   * implementations.
   *
   * Return: 0 on success, errno otherwise
   */
  static int
  event_trigger_callback(struct event_command *cmd_ops,
  		       struct trace_event_file *file,
  		       char *glob, char *cmd, char *param)
  {
  	struct event_trigger_data *trigger_data;
  	struct event_trigger_ops *trigger_ops;
  	char *trigger = NULL;
  	char *number;
  	int ret;
  
  	/* separate the trigger from the filter (t:n [if filter]) */
  	if (param && isdigit(param[0]))
  		trigger = strsep(&param, " \t");
  
  	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
  
  	ret = -ENOMEM;
  	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
  	if (!trigger_data)
  		goto out;
  
  	trigger_data->count = -1;
  	trigger_data->ops = trigger_ops;
  	trigger_data->cmd_ops = cmd_ops;
  	trigger_data->private_data = file;
  	INIT_LIST_HEAD(&trigger_data->list);
  	INIT_LIST_HEAD(&trigger_data->named_list);
  
  	if (glob[0] == '!') {
  		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
  		kfree(trigger_data);
  		ret = 0;
  		goto out;
  	}
  
  	if (trigger) {
  		number = strsep(&trigger, ":");
  
  		ret = -EINVAL;
  		if (!strlen(number))
  			goto out_free;
  
  		/*
  		 * We use the callback data field (which is a pointer)
  		 * as our counter.
  		 */
  		ret = kstrtoul(number, 0, &trigger_data->count);
  		if (ret)
  			goto out_free;
  	}
  
  	if (!param) /* if param is non-empty, it's supposed to be a filter */
  		goto out_reg;
  
  	if (!cmd_ops->set_filter)
  		goto out_reg;
  
  	ret = cmd_ops->set_filter(param, trigger_data, file);
  	if (ret < 0)
  		goto out_free;
  
   out_reg:
  	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
  	/*
  	 * The above returns on success the # of functions enabled,
  	 * but if it didn't find any functions it returns zero.
  	 * Consider no functions a failure too.
  	 */
  	if (!ret) {
  		ret = -ENOENT;
  		goto out_free;
  	} else if (ret < 0)
  		goto out_free;
  	ret = 0;
   out:
  	return ret;
  
   out_free:
  	if (cmd_ops->set_filter)
  		cmd_ops->set_filter(NULL, trigger_data, NULL);
  	kfree(trigger_data);
  	goto out;
  }
  
  /**
   * set_trigger_filter - Generic event_command @set_filter implementation
   * @filter_str: The filter string for the trigger, NULL to remove filter
   * @trigger_data: Trigger-specific data
   * @file: The trace_event_file associated with the event
   *
   * Common implementation for event command filter parsing and filter
   * instantiation.
   *
   * Usually used directly as the @set_filter method in event command
   * implementations.
   *
   * Also used to remove a filter (if filter_str = NULL).
   *
   * Return: 0 on success, errno otherwise
   */
  int set_trigger_filter(char *filter_str,
  		       struct event_trigger_data *trigger_data,
  		       struct trace_event_file *file)
  {
  	struct event_trigger_data *data = trigger_data;
  	struct event_filter *filter = NULL, *tmp;
  	int ret = -EINVAL;
  	char *s;
  
  	if (!filter_str) /* clear the current filter */
  		goto assign;
  
  	s = strsep(&filter_str, " \t");
  
  	if (!strlen(s) || strcmp(s, "if") != 0)
  		goto out;
  
  	if (!filter_str)
  		goto out;
  
  	/* The filter is for the 'trigger' event, not the triggered event */
  	ret = create_event_filter(file->event_call, filter_str, false, &filter);
  	if (ret)
  		goto out;
   assign:
  	tmp = rcu_access_pointer(data->filter);
  
  	rcu_assign_pointer(data->filter, filter);
  
  	if (tmp) {
  		/* Make sure the call is done with the filter */
  		synchronize_sched();
  		free_event_filter(tmp);
  	}
  
  	kfree(data->filter_str);
  	data->filter_str = NULL;
  
  	if (filter_str) {
  		data->filter_str = kstrdup(filter_str, GFP_KERNEL);
  		if (!data->filter_str) {
  			free_event_filter(rcu_access_pointer(data->filter));
  			data->filter = NULL;
  			ret = -ENOMEM;
  		}
  	}
   out:
  	return ret;
  }
  
  static LIST_HEAD(named_triggers);
  
  /**
   * find_named_trigger - Find the common named trigger associated with @name
   * @name: The name of the set of named triggers to find the common data for
   *
   * Named triggers are sets of triggers that share a common set of
   * trigger data.  The first named trigger registered with a given name
   * owns the common trigger data that the others subsequently
   * registered with the same name will reference.  This function
   * returns the common trigger data associated with that first
   * registered instance.
   *
   * Return: the common trigger data for the given named trigger on
   * success, NULL otherwise.
   */
  struct event_trigger_data *find_named_trigger(const char *name)
  {
  	struct event_trigger_data *data;
  
  	if (!name)
  		return NULL;
  
  	list_for_each_entry(data, &named_triggers, named_list) {
  		if (data->named_data)
  			continue;
  		if (strcmp(data->name, name) == 0)
  			return data;
  	}
  
  	return NULL;
  }
  
  /**
   * is_named_trigger - determine if a given trigger is a named trigger
   * @test: The trigger data to test
   *
   * Return: true if 'test' is a named trigger, false otherwise.
   */
  bool is_named_trigger(struct event_trigger_data *test)
  {
  	struct event_trigger_data *data;
  
  	list_for_each_entry(data, &named_triggers, named_list) {
  		if (test == data)
  			return true;
  	}
  
  	return false;
  }
  
  /**
   * save_named_trigger - save the trigger in the named trigger list
   * @name: The name of the named trigger set
   * @data: The trigger data to save
   *
   * Return: 0 if successful, negative error otherwise.
   */
  int save_named_trigger(const char *name, struct event_trigger_data *data)
  {
  	data->name = kstrdup(name, GFP_KERNEL);
  	if (!data->name)
  		return -ENOMEM;
  
  	list_add(&data->named_list, &named_triggers);
  
  	return 0;
  }
  
  /**
   * del_named_trigger - delete a trigger from the named trigger list
   * @data: The trigger data to delete
   */
  void del_named_trigger(struct event_trigger_data *data)
  {
  	kfree(data->name);
  	data->name = NULL;
  
  	list_del(&data->named_list);
  }
  
  static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
  {
  	struct event_trigger_data *test;
  
  	list_for_each_entry(test, &named_triggers, named_list) {
  		if (strcmp(test->name, data->name) == 0) {
  			if (pause) {
  				test->paused_tmp = test->paused;
  				test->paused = true;
  			} else {
  				test->paused = test->paused_tmp;
  			}
  		}
  	}
  }
  
  /**
   * pause_named_trigger - Pause all named triggers with the same name
   * @data: The trigger data of a named trigger to pause
   *
   * Pauses a named trigger along with all other triggers having the
   * same name.  Because named triggers share a common set of data,
   * pausing only one is meaningless, so pausing one named trigger needs
   * to pause all triggers with the same name.
   */
  void pause_named_trigger(struct event_trigger_data *data)
  {
  	__pause_named_trigger(data, true);
  }
  
  /**
   * unpause_named_trigger - Un-pause all named triggers with the same name
   * @data: The trigger data of a named trigger to unpause
   *
   * Un-pauses a named trigger along with all other triggers having the
   * same name.  Because named triggers share a common set of data,
   * unpausing only one is meaningless, so unpausing one named trigger
   * needs to unpause all triggers with the same name.
   */
  void unpause_named_trigger(struct event_trigger_data *data)
  {
  	__pause_named_trigger(data, false);
  }
  
  /**
   * set_named_trigger_data - Associate common named trigger data
   * @data: The trigger data of a named trigger to unpause
   *
   * Named triggers are sets of triggers that share a common set of
   * trigger data.  The first named trigger registered with a given name
   * owns the common trigger data that the others subsequently
   * registered with the same name will reference.  This function
   * associates the common trigger data from the first trigger with the
   * given trigger.
   */
  void set_named_trigger_data(struct event_trigger_data *data,
  			    struct event_trigger_data *named_data)
  {
  	data->named_data = named_data;
  }
  
  struct event_trigger_data *
  get_named_trigger_data(struct event_trigger_data *data)
  {
  	return data->named_data;
  }
  
  static void
  traceon_trigger(struct event_trigger_data *data, void *rec,
  		struct ring_buffer_event *event)
  {
  	if (tracing_is_on())
  		return;
  
  	tracing_on();
  }
  
  static void
  traceon_count_trigger(struct event_trigger_data *data, void *rec,
  		      struct ring_buffer_event *event)
  {
  	if (tracing_is_on())
  		return;
  
  	if (!data->count)
  		return;
  
  	if (data->count != -1)
  		(data->count)--;
  
  	tracing_on();
  }
  
  static void
  traceoff_trigger(struct event_trigger_data *data, void *rec,
  		 struct ring_buffer_event *event)
  {
  	if (!tracing_is_on())
  		return;
  
  	tracing_off();
  }
  
  static void
  traceoff_count_trigger(struct event_trigger_data *data, void *rec,
  		       struct ring_buffer_event *event)
  {
  	if (!tracing_is_on())
  		return;
  
  	if (!data->count)
  		return;
  
  	if (data->count != -1)
  		(data->count)--;
  
  	tracing_off();
  }
  
  static int
  traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
  		      struct event_trigger_data *data)
  {
  	return event_trigger_print("traceon", m, (void *)data->count,
  				   data->filter_str);
  }
  
  static int
  traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
  		       struct event_trigger_data *data)
  {
  	return event_trigger_print("traceoff", m, (void *)data->count,
  				   data->filter_str);
  }
  
  static struct event_trigger_ops traceon_trigger_ops = {
  	.func			= traceon_trigger,
  	.print			= traceon_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops traceon_count_trigger_ops = {
  	.func			= traceon_count_trigger,
  	.print			= traceon_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops traceoff_trigger_ops = {
  	.func			= traceoff_trigger,
  	.print			= traceoff_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops traceoff_count_trigger_ops = {
  	.func			= traceoff_count_trigger,
  	.print			= traceoff_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops *
  onoff_get_trigger_ops(char *cmd, char *param)
  {
  	struct event_trigger_ops *ops;
  
  	/* we register both traceon and traceoff to this callback */
  	if (strcmp(cmd, "traceon") == 0)
  		ops = param ? &traceon_count_trigger_ops :
  			&traceon_trigger_ops;
  	else
  		ops = param ? &traceoff_count_trigger_ops :
  			&traceoff_trigger_ops;
  
  	return ops;
  }
  
  static struct event_command trigger_traceon_cmd = {
  	.name			= "traceon",
  	.trigger_type		= ETT_TRACE_ONOFF,
  	.func			= event_trigger_callback,
  	.reg			= register_trigger,
  	.unreg			= unregister_trigger,
  	.get_trigger_ops	= onoff_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  static struct event_command trigger_traceoff_cmd = {
  	.name			= "traceoff",
  	.trigger_type		= ETT_TRACE_ONOFF,
  	.flags			= EVENT_CMD_FL_POST_TRIGGER,
  	.func			= event_trigger_callback,
  	.reg			= register_trigger,
  	.unreg			= unregister_trigger,
  	.get_trigger_ops	= onoff_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  #ifdef CONFIG_TRACER_SNAPSHOT
  static void
  snapshot_trigger(struct event_trigger_data *data, void *rec,
  		 struct ring_buffer_event *event)
  {
  	struct trace_event_file *file = data->private_data;
  
  	if (file)
  		tracing_snapshot_instance(file->tr);
  	else
  		tracing_snapshot();
  }
  
  static void
  snapshot_count_trigger(struct event_trigger_data *data, void *rec,
  		       struct ring_buffer_event *event)
  {
  	if (!data->count)
  		return;
  
  	if (data->count != -1)
  		(data->count)--;
  
  	snapshot_trigger(data, rec, event);
  }
  
  static int
  register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
  			  struct event_trigger_data *data,
  			  struct trace_event_file *file)
  {
  	int ret = register_trigger(glob, ops, data, file);
  
  	if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
  		unregister_trigger(glob, ops, data, file);
  		ret = 0;
  	}
  
  	return ret;
  }
  
  static int
  snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
  		       struct event_trigger_data *data)
  {
  	return event_trigger_print("snapshot", m, (void *)data->count,
  				   data->filter_str);
  }
  
  static struct event_trigger_ops snapshot_trigger_ops = {
  	.func			= snapshot_trigger,
  	.print			= snapshot_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops snapshot_count_trigger_ops = {
  	.func			= snapshot_count_trigger,
  	.print			= snapshot_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops *
  snapshot_get_trigger_ops(char *cmd, char *param)
  {
  	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
  }
  
  static struct event_command trigger_snapshot_cmd = {
  	.name			= "snapshot",
  	.trigger_type		= ETT_SNAPSHOT,
  	.func			= event_trigger_callback,
  	.reg			= register_snapshot_trigger,
  	.unreg			= unregister_trigger,
  	.get_trigger_ops	= snapshot_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  static __init int register_trigger_snapshot_cmd(void)
  {
  	int ret;
  
  	ret = register_event_command(&trigger_snapshot_cmd);
  	WARN_ON(ret < 0);
  
  	return ret;
  }
  #else
  static __init int register_trigger_snapshot_cmd(void) { return 0; }
  #endif /* CONFIG_TRACER_SNAPSHOT */
  
  #ifdef CONFIG_STACKTRACE
  #ifdef CONFIG_UNWINDER_ORC
  /* Skip 2:
   *   event_triggers_post_call()
   *   trace_event_raw_event_xxx()
   */
  # define STACK_SKIP 2
  #else
  /*
   * Skip 4:
   *   stacktrace_trigger()
   *   event_triggers_post_call()
   *   trace_event_buffer_commit()
   *   trace_event_raw_event_xxx()
   */
  #define STACK_SKIP 4
  #endif
  
  static void
  stacktrace_trigger(struct event_trigger_data *data, void *rec,
  		   struct ring_buffer_event *event)
  {
  	trace_dump_stack(STACK_SKIP);
  }
  
  static void
  stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
  			 struct ring_buffer_event *event)
  {
  	if (!data->count)
  		return;
  
  	if (data->count != -1)
  		(data->count)--;
  
  	stacktrace_trigger(data, rec, event);
  }
  
  static int
  stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
  			 struct event_trigger_data *data)
  {
  	return event_trigger_print("stacktrace", m, (void *)data->count,
  				   data->filter_str);
  }
  
  static struct event_trigger_ops stacktrace_trigger_ops = {
  	.func			= stacktrace_trigger,
  	.print			= stacktrace_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops stacktrace_count_trigger_ops = {
  	.func			= stacktrace_count_trigger,
  	.print			= stacktrace_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_trigger_free,
  };
  
  static struct event_trigger_ops *
  stacktrace_get_trigger_ops(char *cmd, char *param)
  {
  	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
  }
  
  static struct event_command trigger_stacktrace_cmd = {
  	.name			= "stacktrace",
  	.trigger_type		= ETT_STACKTRACE,
  	.flags			= EVENT_CMD_FL_POST_TRIGGER,
  	.func			= event_trigger_callback,
  	.reg			= register_trigger,
  	.unreg			= unregister_trigger,
  	.get_trigger_ops	= stacktrace_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  static __init int register_trigger_stacktrace_cmd(void)
  {
  	int ret;
  
  	ret = register_event_command(&trigger_stacktrace_cmd);
  	WARN_ON(ret < 0);
  
  	return ret;
  }
  #else
  static __init int register_trigger_stacktrace_cmd(void) { return 0; }
  #endif /* CONFIG_STACKTRACE */
  
  static __init void unregister_trigger_traceon_traceoff_cmds(void)
  {
  	unregister_event_command(&trigger_traceon_cmd);
  	unregister_event_command(&trigger_traceoff_cmd);
  }
  
  static void
  event_enable_trigger(struct event_trigger_data *data, void *rec,
  		     struct ring_buffer_event *event)
  {
  	struct enable_trigger_data *enable_data = data->private_data;
  
  	if (enable_data->enable)
  		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
  	else
  		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
  }
  
  static void
  event_enable_count_trigger(struct event_trigger_data *data, void *rec,
  			   struct ring_buffer_event *event)
  {
  	struct enable_trigger_data *enable_data = data->private_data;
  
  	if (!data->count)
  		return;
  
  	/* Skip if the event is in a state we want to switch to */
  	if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
  		return;
  
  	if (data->count != -1)
  		(data->count)--;
  
  	event_enable_trigger(data, rec, event);
  }
  
  int event_enable_trigger_print(struct seq_file *m,
  			       struct event_trigger_ops *ops,
  			       struct event_trigger_data *data)
  {
  	struct enable_trigger_data *enable_data = data->private_data;
  
  	seq_printf(m, "%s:%s:%s",
  		   enable_data->hist ?
  		   (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
  		   (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
  		   enable_data->file->event_call->class->system,
  		   trace_event_name(enable_data->file->event_call));
  
  	if (data->count == -1)
  		seq_puts(m, ":unlimited");
  	else
  		seq_printf(m, ":count=%ld", data->count);
  
  	if (data->filter_str)
  		seq_printf(m, " if %s\n", data->filter_str);
  	else
  		seq_putc(m, '\n');
  
  	return 0;
  }
  
  void event_enable_trigger_free(struct event_trigger_ops *ops,
  			       struct event_trigger_data *data)
  {
  	struct enable_trigger_data *enable_data = data->private_data;
  
  	if (WARN_ON_ONCE(data->ref <= 0))
  		return;
  
  	data->ref--;
  	if (!data->ref) {
  		/* Remove the SOFT_MODE flag */
  		trace_event_enable_disable(enable_data->file, 0, 1);
  		module_put(enable_data->file->event_call->mod);
  		trigger_data_free(data);
  		kfree(enable_data);
  	}
  }
  
  static struct event_trigger_ops event_enable_trigger_ops = {
  	.func			= event_enable_trigger,
  	.print			= event_enable_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_enable_trigger_free,
  };
  
  static struct event_trigger_ops event_enable_count_trigger_ops = {
  	.func			= event_enable_count_trigger,
  	.print			= event_enable_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_enable_trigger_free,
  };
  
  static struct event_trigger_ops event_disable_trigger_ops = {
  	.func			= event_enable_trigger,
  	.print			= event_enable_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_enable_trigger_free,
  };
  
  static struct event_trigger_ops event_disable_count_trigger_ops = {
  	.func			= event_enable_count_trigger,
  	.print			= event_enable_trigger_print,
  	.init			= event_trigger_init,
  	.free			= event_enable_trigger_free,
  };
  
  int event_enable_trigger_func(struct event_command *cmd_ops,
  			      struct trace_event_file *file,
  			      char *glob, char *cmd, char *param)
  {
  	struct trace_event_file *event_enable_file;
  	struct enable_trigger_data *enable_data;
  	struct event_trigger_data *trigger_data;
  	struct event_trigger_ops *trigger_ops;
  	struct trace_array *tr = file->tr;
  	const char *system;
  	const char *event;
  	bool hist = false;
  	char *trigger;
  	char *number;
  	bool enable;
  	int ret;
  
  	if (!param)
  		return -EINVAL;
  
  	/* separate the trigger from the filter (s:e:n [if filter]) */
  	trigger = strsep(&param, " \t");
  	if (!trigger)
  		return -EINVAL;
  
  	system = strsep(&trigger, ":");
  	if (!trigger)
  		return -EINVAL;
  
  	event = strsep(&trigger, ":");
  
  	ret = -EINVAL;
  	event_enable_file = find_event_file(tr, system, event);
  	if (!event_enable_file)
  		goto out;
  
  #ifdef CONFIG_HIST_TRIGGERS
  	hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
  		(strcmp(cmd, DISABLE_HIST_STR) == 0));
  
  	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
  		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
  #else
  	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
  #endif
  	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
  
  	ret = -ENOMEM;
  	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
  	if (!trigger_data)
  		goto out;
  
  	enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
  	if (!enable_data) {
  		kfree(trigger_data);
  		goto out;
  	}
  
  	trigger_data->count = -1;
  	trigger_data->ops = trigger_ops;
  	trigger_data->cmd_ops = cmd_ops;
  	INIT_LIST_HEAD(&trigger_data->list);
  	RCU_INIT_POINTER(trigger_data->filter, NULL);
  
  	enable_data->hist = hist;
  	enable_data->enable = enable;
  	enable_data->file = event_enable_file;
  	trigger_data->private_data = enable_data;
  
  	if (glob[0] == '!') {
  		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
  		kfree(trigger_data);
  		kfree(enable_data);
  		ret = 0;
  		goto out;
  	}
  
  	if (trigger) {
  		number = strsep(&trigger, ":");
  
  		ret = -EINVAL;
  		if (!strlen(number))
  			goto out_free;
  
  		/*
  		 * We use the callback data field (which is a pointer)
  		 * as our counter.
  		 */
  		ret = kstrtoul(number, 0, &trigger_data->count);
  		if (ret)
  			goto out_free;
  	}
  
  	if (!param) /* if param is non-empty, it's supposed to be a filter */
  		goto out_reg;
  
  	if (!cmd_ops->set_filter)
  		goto out_reg;
  
  	ret = cmd_ops->set_filter(param, trigger_data, file);
  	if (ret < 0)
  		goto out_free;
  
   out_reg:
  	/* Don't let event modules unload while probe registered */
  	ret = try_module_get(event_enable_file->event_call->mod);
  	if (!ret) {
  		ret = -EBUSY;
  		goto out_free;
  	}
  
  	ret = trace_event_enable_disable(event_enable_file, 1, 1);
  	if (ret < 0)
  		goto out_put;
  	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
  	/*
  	 * The above returns on success the # of functions enabled,
  	 * but if it didn't find any functions it returns zero.
  	 * Consider no functions a failure too.
  	 */
  	if (!ret) {
  		ret = -ENOENT;
  		goto out_disable;
  	} else if (ret < 0)
  		goto out_disable;
  	/* Just return zero, not the number of enabled functions */
  	ret = 0;
   out:
  	return ret;
  
   out_disable:
  	trace_event_enable_disable(event_enable_file, 0, 1);
   out_put:
  	module_put(event_enable_file->event_call->mod);
   out_free:
  	if (cmd_ops->set_filter)
  		cmd_ops->set_filter(NULL, trigger_data, NULL);
  	kfree(trigger_data);
  	kfree(enable_data);
  	goto out;
  }
  
  int event_enable_register_trigger(char *glob,
  				  struct event_trigger_ops *ops,
  				  struct event_trigger_data *data,
  				  struct trace_event_file *file)
  {
  	struct enable_trigger_data *enable_data = data->private_data;
  	struct enable_trigger_data *test_enable_data;
  	struct event_trigger_data *test;
  	int ret = 0;
  
  	list_for_each_entry_rcu(test, &file->triggers, list) {
  		test_enable_data = test->private_data;
  		if (test_enable_data &&
  		    (test->cmd_ops->trigger_type ==
  		     data->cmd_ops->trigger_type) &&
  		    (test_enable_data->file == enable_data->file)) {
  			ret = -EEXIST;
  			goto out;
  		}
  	}
  
  	if (data->ops->init) {
  		ret = data->ops->init(data->ops, data);
  		if (ret < 0)
  			goto out;
  	}
  
  	list_add_rcu(&data->list, &file->triggers);
  	ret++;
  
  	update_cond_flag(file);
  	if (trace_event_trigger_enable_disable(file, 1) < 0) {
  		list_del_rcu(&data->list);
  		update_cond_flag(file);
  		ret--;
  	}
  out:
  	return ret;
  }
  
  void event_enable_unregister_trigger(char *glob,
  				     struct event_trigger_ops *ops,
  				     struct event_trigger_data *test,
  				     struct trace_event_file *file)
  {
  	struct enable_trigger_data *test_enable_data = test->private_data;
  	struct enable_trigger_data *enable_data;
  	struct event_trigger_data *data;
  	bool unregistered = false;
  
  	list_for_each_entry_rcu(data, &file->triggers, list) {
  		enable_data = data->private_data;
  		if (enable_data &&
  		    (data->cmd_ops->trigger_type ==
  		     test->cmd_ops->trigger_type) &&
  		    (enable_data->file == test_enable_data->file)) {
  			unregistered = true;
  			list_del_rcu(&data->list);
  			trace_event_trigger_enable_disable(file, 0);
  			update_cond_flag(file);
  			break;
  		}
  	}
  
  	if (unregistered && data->ops->free)
  		data->ops->free(data->ops, data);
  }
  
  static struct event_trigger_ops *
  event_enable_get_trigger_ops(char *cmd, char *param)
  {
  	struct event_trigger_ops *ops;
  	bool enable;
  
  #ifdef CONFIG_HIST_TRIGGERS
  	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
  		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
  #else
  	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
  #endif
  	if (enable)
  		ops = param ? &event_enable_count_trigger_ops :
  			&event_enable_trigger_ops;
  	else
  		ops = param ? &event_disable_count_trigger_ops :
  			&event_disable_trigger_ops;
  
  	return ops;
  }
  
  static struct event_command trigger_enable_cmd = {
  	.name			= ENABLE_EVENT_STR,
  	.trigger_type		= ETT_EVENT_ENABLE,
  	.func			= event_enable_trigger_func,
  	.reg			= event_enable_register_trigger,
  	.unreg			= event_enable_unregister_trigger,
  	.get_trigger_ops	= event_enable_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  static struct event_command trigger_disable_cmd = {
  	.name			= DISABLE_EVENT_STR,
  	.trigger_type		= ETT_EVENT_ENABLE,
  	.func			= event_enable_trigger_func,
  	.reg			= event_enable_register_trigger,
  	.unreg			= event_enable_unregister_trigger,
  	.get_trigger_ops	= event_enable_get_trigger_ops,
  	.set_filter		= set_trigger_filter,
  };
  
  static __init void unregister_trigger_enable_disable_cmds(void)
  {
  	unregister_event_command(&trigger_enable_cmd);
  	unregister_event_command(&trigger_disable_cmd);
  }
  
  static __init int register_trigger_enable_disable_cmds(void)
  {
  	int ret;
  
  	ret = register_event_command(&trigger_enable_cmd);
  	if (WARN_ON(ret < 0))
  		return ret;
  	ret = register_event_command(&trigger_disable_cmd);
  	if (WARN_ON(ret < 0))
  		unregister_trigger_enable_disable_cmds();
  
  	return ret;
  }
  
  static __init int register_trigger_traceon_traceoff_cmds(void)
  {
  	int ret;
  
  	ret = register_event_command(&trigger_traceon_cmd);
  	if (WARN_ON(ret < 0))
  		return ret;
  	ret = register_event_command(&trigger_traceoff_cmd);
  	if (WARN_ON(ret < 0))
  		unregister_trigger_traceon_traceoff_cmds();
  
  	return ret;
  }
  
  __init int register_trigger_cmds(void)
  {
  	register_trigger_traceon_traceoff_cmds();
  	register_trigger_snapshot_cmd();
  	register_trigger_stacktrace_cmd();
  	register_trigger_enable_disable_cmds();
  	register_trigger_hist_enable_disable_cmds();
  	register_trigger_hist_cmd();
  
  	return 0;
  }
  