linux/kernel/trace/trace_events_trigger.c
Masami Hiramatsu 6784beada6 tracing: Fix event trigger to accept redundant spaces
Fix the event trigger to accept redundant spaces in
the trigger input.

For example, these return -EINVAL

echo " traceon" > events/ftrace/print/trigger
echo "traceon  if common_pid == 0" > events/ftrace/print/trigger
echo "disable_event:kmem:kmalloc " > events/ftrace/print/trigger

But these are hard to find what is wrong.

To fix this issue, use skip_spaces() to remove spaces
in front of actual tokens, and set NULL if there is no
token.

Link: http://lkml.kernel.org/r/159262476352.185015.5261566783045364186.stgit@devnote2

Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 85f2b08268 ("tracing: Add basic event trigger framework")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-06-23 21:51:40 -04:00

1669 lines
41 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
* @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) {
(*pos)++;
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;
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->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)
{
/* 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
* @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;
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
* @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;
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->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.
*/
static 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;
lockdep_assert_held(&event_mutex);
list_for_each_entry(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");
if (param) {
param = skip_spaces(param);
if (!*param)
param = NULL;
}
}
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:
/* Up the trigger_data count to make sure reg doesn't free it on failure */
event_trigger_init(trigger_ops, trigger_data);
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) {
cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
ret = -ENOENT;
} else if (ret > 0)
ret = 0;
/* Down the counter of trigger_data or free it if not used anymore */
event_trigger_free(trigger_ops, trigger_data);
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->tr, file->event_call,
filter_str, false, &filter);
/*
* 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 */
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 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)
{
if (tracing_alloc_snapshot_instance(file->tr) != 0)
return 0;
return register_trigger(glob, ops, data, file);
}
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;
if (param) {
param = skip_spaces(param);
if (!*param)
param = NULL;
}
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;
}
/* Up the trigger_data count to make sure nothing frees it on failure */
event_trigger_init(trigger_ops, trigger_data);
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;
event_trigger_free(trigger_ops, trigger_data);
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);
event_trigger_free(trigger_ops, 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;
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->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;
lockdep_assert_held(&event_mutex);
list_for_each_entry(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;
}