linux/kernel/trace/trace_events_trigger.c
Steven Rostedt (Google) 2048fdc275 tracing: Decrement the snapshot if the snapshot trigger fails to register
Running the ftrace selftests caused the ring buffer mapping test to fail.
Investigating, I found that the snapshot counter would be incremented
every time a snapshot trigger was added, even if that snapshot trigger
failed.

 # cd /sys/kernel/tracing
 # echo "snapshot" > events/sched/sched_process_fork/trigger
 # echo "snapshot" > events/sched/sched_process_fork/trigger
 -bash: echo: write error: File exists

That second one that fails increments the snapshot counter but doesn't
decrement it. It needs to be decremented when the snapshot fails.

Link: https://lore.kernel.org/linux-trace-kernel/20240223013344.729055907@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Fixes: 16f7e48ffc53a ("tracing: Add snapshot refcount")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-18 10:33:05 -04:00

2027 lines
52 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* trace_events_trigger - trace event triggers
*
* Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
*/
#include <linux/security.h>
#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);
/* make sure current triggers exit before free */
tracepoint_synchronize_unregister();
kfree(data);
}
/**
* event_triggers_call - Call triggers associated with a trace event
* @file: The trace_event_file associated with the event
* @buffer: The ring buffer that the event is being written to
* @rec: The trace entry for the event, NULL for unconditional invocation
* @event: The event meta data in the ring buffer
*
* 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,
struct trace_buffer *buffer, 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->trigger(data, buffer, 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->trigger(data, buffer, rec, event);
}
return tt;
}
EXPORT_SYMBOL_GPL(event_triggers_call);
bool __trace_trigger_soft_disabled(struct trace_event_file *file)
{
unsigned long eflags = file->flags;
if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
event_triggers_call(file, NULL, NULL, NULL);
if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
return true;
if (eflags & EVENT_FILE_FL_PID_FILTER)
return trace_event_ignore_this_pid(file);
return false;
}
EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled);
/**
* 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->trigger(data, NULL, 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) {
(*pos)++;
return NULL;
}
return seq_list_next(t, &event_file->triggers, pos);
}
static bool check_user_trigger(struct trace_event_file *file)
{
struct event_trigger_data *data;
list_for_each_entry_rcu(data, &file->triggers, list,
lockdep_is_held(&event_mutex)) {
if (data->flags & EVENT_TRIGGER_FL_PROBE)
continue;
return true;
}
return false;
}
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) || !check_user_trigger(event_file))
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);
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;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
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;
}
int trigger_process_regex(struct trace_event_file *file, char *buff)
{
char *command, *next;
struct event_command *p;
int ret = -EINVAL;
next = buff = skip_spaces(buff);
command = strsep(&next, ": \t");
if (next) {
next = skip_spaces(next);
if (!*next)
next = NULL;
}
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->parse(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)
{
/* Checks for tracefs lockdown */
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
* @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_data *data)
{
data->ref++;
return 0;
}
/**
* event_trigger_free - Generic event_trigger_ops @free implementation
* @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_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);
}
}
}
/**
* 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;
lockdep_assert_held(&event_mutex);
list_for_each_entry(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
* @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_data *data,
struct trace_event_file *file)
{
struct event_trigger_data *test;
int ret = 0;
lockdep_assert_held(&event_mutex);
list_for_each_entry(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);
if (ret < 0)
goto out;
}
list_add_rcu(&data->list, &file->triggers);
update_cond_flag(file);
ret = trace_event_trigger_enable_disable(file, 1);
if (ret < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
}
out:
return ret;
}
/*
* True if the trigger was found and unregistered, else false.
*/
static bool try_unregister_trigger(char *glob,
struct event_trigger_data *test,
struct trace_event_file *file)
{
struct event_trigger_data *data = NULL, *iter;
lockdep_assert_held(&event_mutex);
list_for_each_entry(iter, &file->triggers, list) {
if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
data = iter;
list_del_rcu(&data->list);
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
break;
}
}
if (data) {
if (data->ops->free)
data->ops->free(data);
return true;
}
return false;
}
/**
* unregister_trigger - Generic event_command @unreg implementation
* @glob: The raw string used to register 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.
*/
static void unregister_trigger(char *glob,
struct event_trigger_data *test,
struct trace_event_file *file)
{
try_unregister_trigger(glob, test, file);
}
/*
* Event trigger parsing helper functions.
*
* These functions help make it easier to write an event trigger
* parsing function i.e. the struct event_command.parse() callback
* function responsible for parsing and registering a trigger command
* written to the 'trigger' file.
*
* A trigger command (or just 'trigger' for short) takes the form:
* [trigger] [if filter]
*
* The struct event_command.parse() callback (and other struct
* event_command functions) refer to several components of a trigger
* command. Those same components are referenced by the event trigger
* parsing helper functions defined below. These components are:
*
* cmd - the trigger command name
* glob - the trigger command name optionally prefaced with '!'
* param_and_filter - text following cmd and ':'
* param - text following cmd and ':' and stripped of filter
* filter - the optional filter text following (and including) 'if'
*
* To illustrate the use of these componenents, here are some concrete
* examples. For the following triggers:
*
* echo 'traceon:5 if pid == 0' > trigger
* - 'traceon' is both cmd and glob
* - '5 if pid == 0' is the param_and_filter
* - '5' is the param
* - 'if pid == 0' is the filter
*
* echo 'enable_event:sys:event:n' > trigger
* - 'enable_event' is both cmd and glob
* - 'sys:event:n' is the param_and_filter
* - 'sys:event:n' is the param
* - there is no filter
*
* echo 'hist:keys=pid if prio > 50' > trigger
* - 'hist' is both cmd and glob
* - 'keys=pid if prio > 50' is the param_and_filter
* - 'keys=pid' is the param
* - 'if prio > 50' is the filter
*
* echo '!enable_event:sys:event:n' > trigger
* - 'enable_event' the cmd
* - '!enable_event' is the glob
* - 'sys:event:n' is the param_and_filter
* - 'sys:event:n' is the param
* - there is no filter
*
* echo 'traceoff' > trigger
* - 'traceoff' is both cmd and glob
* - there is no param_and_filter
* - there is no param
* - there is no filter
*
* There are a few different categories of event trigger covered by
* these helpers:
*
* - triggers that don't require a parameter e.g. traceon
* - triggers that do require a parameter e.g. enable_event and hist
* - triggers that though they may not require a param may support an
* optional 'n' param (n = number of times the trigger should fire)
* e.g.: traceon:5 or enable_event:sys:event:n
* - triggers that do not support an 'n' param e.g. hist
*
* These functions can be used or ignored as necessary - it all
* depends on the complexity of the trigger, and the granularity of
* the functions supported reflects the fact that some implementations
* may need to customize certain aspects of their implementations and
* won't need certain functions. For instance, the hist trigger
* implementation doesn't use event_trigger_separate_filter() because
* it has special requirements for handling the filter.
*/
/**
* event_trigger_check_remove - check whether an event trigger specifies remove
* @glob: The trigger command string, with optional remove(!) operator
*
* The event trigger callback implementations pass in 'glob' as a
* parameter. This is the command name either with or without a
* remove(!) operator. This function simply parses the glob and
* determines whether the command corresponds to a trigger removal or
* a trigger addition.
*
* Return: true if this is a remove command, false otherwise
*/
bool event_trigger_check_remove(const char *glob)
{
return (glob && glob[0] == '!') ? true : false;
}
/**
* event_trigger_empty_param - check whether the param is empty
* @param: The trigger param string
*
* The event trigger callback implementations pass in 'param' as a
* parameter. This corresponds to the string following the command
* name minus the command name. This function can be called by a
* callback implementation for any command that requires a param; a
* callback that doesn't require a param can ignore it.
*
* Return: true if this is an empty param, false otherwise
*/
bool event_trigger_empty_param(const char *param)
{
return !param;
}
/**
* event_trigger_separate_filter - separate an event trigger from a filter
* @param_and_filter: String containing trigger and possibly filter
* @param: outparam, will be filled with a pointer to the trigger
* @filter: outparam, will be filled with a pointer to the filter
* @param_required: Specifies whether or not the param string is required
*
* Given a param string of the form '[trigger] [if filter]', this
* function separates the filter from the trigger and returns the
* trigger in @param and the filter in @filter. Either the @param
* or the @filter may be set to NULL by this function - if not set to
* NULL, they will contain strings corresponding to the trigger and
* filter.
*
* There are two cases that need to be handled with respect to the
* passed-in param: either the param is required, or it is not
* required. If @param_required is set, and there's no param, it will
* return -EINVAL. If @param_required is not set and there's a param
* that starts with a number, that corresponds to the case of a
* trigger with :n (n = number of times the trigger should fire) and
* the parsing continues normally; otherwise the function just returns
* and assumes param just contains a filter and there's nothing else
* to do.
*
* Return: 0 on success, errno otherwise
*/
int event_trigger_separate_filter(char *param_and_filter, char **param,
char **filter, bool param_required)
{
int ret = 0;
*param = *filter = NULL;
if (!param_and_filter) {
if (param_required)
ret = -EINVAL;
goto out;
}
/*
* Here we check for an optional param. The only legal
* optional param is :n, and if that's the case, continue
* below. Otherwise we assume what's left is a filter and
* return it as the filter string for the caller to deal with.
*/
if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
*filter = param_and_filter;
goto out;
}
/*
* Separate the param from the filter (param [if filter]).
* Here we have either an optional :n param or a required
* param and an optional filter.
*/
*param = strsep(&param_and_filter, " \t");
/*
* Here we have a filter, though it may be empty.
*/
if (param_and_filter) {
*filter = skip_spaces(param_and_filter);
if (!**filter)
*filter = NULL;
}
out:
return ret;
}
/**
* event_trigger_alloc - allocate and init event_trigger_data for a trigger
* @cmd_ops: The event_command operations for the trigger
* @cmd: The cmd string
* @param: The param string
* @private_data: User data to associate with the event trigger
*
* Allocate an event_trigger_data instance and initialize it. The
* @cmd_ops are used along with the @cmd and @param to get the
* trigger_ops to assign to the event_trigger_data. @private_data can
* also be passed in and associated with the event_trigger_data.
*
* Use event_trigger_free() to free an event_trigger_data object.
*
* Return: The trigger_data object success, NULL otherwise
*/
struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
char *cmd,
char *param,
void *private_data)
{
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
if (!trigger_data)
return NULL;
trigger_data->count = -1;
trigger_data->ops = trigger_ops;
trigger_data->cmd_ops = cmd_ops;
trigger_data->private_data = private_data;
INIT_LIST_HEAD(&trigger_data->list);
INIT_LIST_HEAD(&trigger_data->named_list);
RCU_INIT_POINTER(trigger_data->filter, NULL);
return trigger_data;
}
/**
* event_trigger_parse_num - parse and return the number param for a trigger
* @param: The param string
* @trigger_data: The trigger_data for the trigger
*
* Parse the :n (n = number of times the trigger should fire) param
* and set the count variable in the trigger_data to the parsed count.
*
* Return: 0 on success, errno otherwise
*/
int event_trigger_parse_num(char *param,
struct event_trigger_data *trigger_data)
{
char *number;
int ret = 0;
if (param) {
number = strsep(&param, ":");
if (!strlen(number))
return -EINVAL;
/*
* We use the callback data field (which is a pointer)
* as our counter.
*/
ret = kstrtoul(number, 0, &trigger_data->count);
}
return ret;
}
/**
* event_trigger_set_filter - set an event trigger's filter
* @cmd_ops: The event_command operations for the trigger
* @file: The event file for the trigger's event
* @param: The string containing the filter
* @trigger_data: The trigger_data for the trigger
*
* Set the filter for the trigger. If the filter is NULL, just return
* without error.
*
* Return: 0 on success, errno otherwise
*/
int event_trigger_set_filter(struct event_command *cmd_ops,
struct trace_event_file *file,
char *param,
struct event_trigger_data *trigger_data)
{
if (param && cmd_ops->set_filter)
return cmd_ops->set_filter(param, trigger_data, file);
return 0;
}
/**
* event_trigger_reset_filter - reset an event trigger's filter
* @cmd_ops: The event_command operations for the trigger
* @trigger_data: The trigger_data for the trigger
*
* Reset the filter for the trigger to no filter.
*/
void event_trigger_reset_filter(struct event_command *cmd_ops,
struct event_trigger_data *trigger_data)
{
if (cmd_ops->set_filter)
cmd_ops->set_filter(NULL, trigger_data, NULL);
}
/**
* event_trigger_register - register an event trigger
* @cmd_ops: The event_command operations for the trigger
* @file: The event file for the trigger's event
* @glob: The trigger command string, with optional remove(!) operator
* @trigger_data: The trigger_data for the trigger
*
* Register an event trigger. The @cmd_ops are used to call the
* cmd_ops->reg() function which actually does the registration.
*
* Return: 0 on success, errno otherwise
*/
int event_trigger_register(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob,
struct event_trigger_data *trigger_data)
{
return cmd_ops->reg(glob, trigger_data, file);
}
/**
* event_trigger_unregister - unregister an event trigger
* @cmd_ops: The event_command operations for the trigger
* @file: The event file for the trigger's event
* @glob: The trigger command string, with optional remove(!) operator
* @trigger_data: The trigger_data for the trigger
*
* Unregister an event trigger. The @cmd_ops are used to call the
* cmd_ops->unreg() function which actually does the unregistration.
*/
void event_trigger_unregister(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob,
struct event_trigger_data *trigger_data)
{
cmd_ops->unreg(glob, trigger_data, file);
}
/*
* End event trigger parsing helper functions.
*/
/**
* event_trigger_parse - Generic event_command @parse 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_and_filter: The param and filter portion of the string used to register the trigger
*
* Common implementation for event command parsing and trigger
* instantiation.
*
* Usually used directly as the @parse method in event command
* implementations.
*
* Return: 0 on success, errno otherwise
*/
static int
event_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param_and_filter)
{
struct event_trigger_data *trigger_data;
char *param, *filter;
bool remove;
int ret;
remove = event_trigger_check_remove(glob);
ret = event_trigger_separate_filter(param_and_filter, &param, &filter, false);
if (ret)
return ret;
ret = -ENOMEM;
trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
if (!trigger_data)
goto out;
if (remove) {
event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
kfree(trigger_data);
ret = 0;
goto out;
}
ret = event_trigger_parse_num(param, trigger_data);
if (ret)
goto out_free;
ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
if (ret < 0)
goto out_free;
/* Up the trigger_data count to make sure reg doesn't free it on failure */
event_trigger_init(trigger_data);
ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
if (ret)
goto out_free;
/* Down the counter of trigger_data or free it if not used anymore */
event_trigger_free(trigger_data);
out:
return ret;
out_free:
event_trigger_reset_filter(cmd_ops, trigger_data);
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->tr, file->event_call,
filter_str, true, &filter);
/* Only enabled set_str for error handling */
if (filter) {
kfree(filter->filter_string);
filter->filter_string = NULL;
}
/*
* If create_event_filter() fails, filter still needs to be freed.
* Which the calling code will do with data->filter.
*/
assign:
tmp = rcu_access_pointer(data->filter);
rcu_assign_pointer(data->filter, filter);
if (tmp) {
/*
* Make sure the call is done with the filter.
* It is possible that a filter could fail at boot up,
* and then this path will be called. Avoid the synchronization
* in that case.
*/
if (system_state != SYSTEM_BOOTING)
tracepoint_synchronize_unregister();
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 to associate
* @named_data: The common named trigger to be associated
*
* 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,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (tracer_tracing_is_on(file->tr))
return;
tracer_tracing_on(file->tr);
return;
}
if (tracing_is_on())
return;
tracing_on();
}
static void
traceon_count_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (tracer_tracing_is_on(file->tr))
return;
} else {
if (tracing_is_on())
return;
}
if (!data->count)
return;
if (data->count != -1)
(data->count)--;
if (file)
tracer_tracing_on(file->tr);
else
tracing_on();
}
static void
traceoff_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (!tracer_tracing_is_on(file->tr))
return;
tracer_tracing_off(file->tr);
return;
}
if (!tracing_is_on())
return;
tracing_off();
}
static void
traceoff_count_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (!tracer_tracing_is_on(file->tr))
return;
} else {
if (!tracing_is_on())
return;
}
if (!data->count)
return;
if (data->count != -1)
(data->count)--;
if (file)
tracer_tracing_off(file->tr);
else
tracing_off();
}
static int
traceon_trigger_print(struct seq_file *m, 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_data *data)
{
return event_trigger_print("traceoff", m, (void *)data->count,
data->filter_str);
}
static struct event_trigger_ops traceon_trigger_ops = {
.trigger = traceon_trigger,
.print = traceon_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceon_count_trigger_ops = {
.trigger = traceon_count_trigger,
.print = traceon_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceoff_trigger_ops = {
.trigger = traceoff_trigger,
.print = traceoff_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceoff_count_trigger_ops = {
.trigger = 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,
.parse = event_trigger_parse,
.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,
.parse = event_trigger_parse,
.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,
struct trace_buffer *buffer, 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,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
if (!data->count)
return;
if (data->count != -1)
(data->count)--;
snapshot_trigger(data, buffer, rec, event);
}
static int
register_snapshot_trigger(char *glob,
struct event_trigger_data *data,
struct trace_event_file *file)
{
int ret = tracing_arm_snapshot(file->tr);
if (ret < 0)
return ret;
ret = register_trigger(glob, data, file);
if (ret < 0)
tracing_disarm_snapshot(file->tr);
return ret;
}
static void unregister_snapshot_trigger(char *glob,
struct event_trigger_data *data,
struct trace_event_file *file)
{
if (try_unregister_trigger(glob, data, file))
tracing_disarm_snapshot(file->tr);
}
static int
snapshot_trigger_print(struct seq_file *m, 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 = {
.trigger = snapshot_trigger,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops snapshot_count_trigger_ops = {
.trigger = 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,
.parse = event_trigger_parse,
.reg = register_snapshot_trigger,
.unreg = unregister_snapshot_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,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file)
__trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
else
trace_dump_stack(STACK_SKIP);
}
static void
stacktrace_count_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
if (!data->count)
return;
if (data->count != -1)
(data->count)--;
stacktrace_trigger(data, buffer, rec, event);
}
static int
stacktrace_trigger_print(struct seq_file *m, 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 = {
.trigger = stacktrace_trigger,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops stacktrace_count_trigger_ops = {
.trigger = 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,
.parse = event_trigger_parse,
.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,
struct trace_buffer *buffer, 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,
struct trace_buffer *buffer, 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, buffer, rec, event);
}
int event_enable_trigger_print(struct seq_file *m,
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_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);
trace_event_put_ref(enable_data->file->event_call);
trigger_data_free(data);
kfree(enable_data);
}
}
static struct event_trigger_ops event_enable_trigger_ops = {
.trigger = 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 = {
.trigger = 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 = {
.trigger = 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 = {
.trigger = event_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
int event_enable_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param_and_filter)
{
struct trace_event_file *event_enable_file;
struct enable_trigger_data *enable_data;
struct event_trigger_data *trigger_data;
struct trace_array *tr = file->tr;
char *param, *filter;
bool enable, remove;
const char *system;
const char *event;
bool hist = false;
int ret;
remove = event_trigger_check_remove(glob);
if (event_trigger_empty_param(param_and_filter))
return -EINVAL;
ret = event_trigger_separate_filter(param_and_filter, &param, &filter, true);
if (ret)
return ret;
system = strsep(&param, ":");
if (!param)
return -EINVAL;
event = strsep(&param, ":");
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
ret = -ENOMEM;
enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
if (!enable_data)
goto out;
enable_data->hist = hist;
enable_data->enable = enable;
enable_data->file = event_enable_file;
trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
if (!trigger_data) {
kfree(enable_data);
goto out;
}
if (remove) {
event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
kfree(trigger_data);
kfree(enable_data);
ret = 0;
goto out;
}
/* Up the trigger_data count to make sure nothing frees it on failure */
event_trigger_init(trigger_data);
ret = event_trigger_parse_num(param, trigger_data);
if (ret)
goto out_free;
ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
if (ret < 0)
goto out_free;
/* Don't let event modules unload while probe registered */
ret = trace_event_try_get_ref(event_enable_file->event_call);
if (!ret) {
ret = -EBUSY;
goto out_free;
}
ret = trace_event_enable_disable(event_enable_file, 1, 1);
if (ret < 0)
goto out_put;
ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
if (ret)
goto out_disable;
event_trigger_free(trigger_data);
out:
return ret;
out_disable:
trace_event_enable_disable(event_enable_file, 0, 1);
out_put:
trace_event_put_ref(event_enable_file->event_call);
out_free:
event_trigger_reset_filter(cmd_ops, trigger_data);
event_trigger_free(trigger_data);
kfree(enable_data);
goto out;
}
int event_enable_register_trigger(char *glob,
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;
lockdep_assert_held(&event_mutex);
list_for_each_entry(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);
if (ret < 0)
goto out;
}
list_add_rcu(&data->list, &file->triggers);
update_cond_flag(file);
ret = trace_event_trigger_enable_disable(file, 1);
if (ret < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
}
out:
return ret;
}
void event_enable_unregister_trigger(char *glob,
struct event_trigger_data *test,
struct trace_event_file *file)
{
struct enable_trigger_data *test_enable_data = test->private_data;
struct event_trigger_data *data = NULL, *iter;
struct enable_trigger_data *enable_data;
lockdep_assert_held(&event_mutex);
list_for_each_entry(iter, &file->triggers, list) {
enable_data = iter->private_data;
if (enable_data &&
(iter->cmd_ops->trigger_type ==
test->cmd_ops->trigger_type) &&
(enable_data->file == test_enable_data->file)) {
data = iter;
list_del_rcu(&data->list);
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
break;
}
}
if (data && data->ops->free)
data->ops->free(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,
.parse = event_enable_trigger_parse,
.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,
.parse = event_enable_trigger_parse,
.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;
}