linux/kernel/trace/trace_events_trigger.c
Steven Rostedt (VMware) 17911ff38a tracing: Add locked_down checks to the open calls of files created for tracefs
Added various checks on open tracefs calls to see if tracefs is in lockdown
mode, and if so, to return -EPERM.

Note, the event format files (which are basically standard on all machines)
as well as the enabled_functions file (which shows what is currently being
traced) are not lockde down. Perhaps they should be, but it seems counter
intuitive to lockdown information to help you know if the system has been
modified.

Link: http://lkml.kernel.org/r/CAHk-=wj7fGPKUspr579Cii-w_y60PtRaiDgKuxVtBAMK0VNNkA@mail.gmail.com

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-10-12 20:48:06 -04:00

1645 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)
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;
}
static int trigger_process_regex(struct trace_event_file *file, char *buff)
{
char *command, *next = buff;
struct event_command *p;
int ret = -EINVAL;
command = strsep(&next, ": \t");
command = (command[0] != '!') ? command : command + 1;
mutex_lock(&trigger_cmd_mutex);
list_for_each_entry(p, &trigger_commands, list) {
if (strcmp(p->name, command) == 0) {
ret = p->func(p, file, buff, command, next);
goto out_unlock;
}
}
out_unlock:
mutex_unlock(&trigger_cmd_mutex);
return ret;
}
static ssize_t event_trigger_regex_write(struct file *file,
const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_event_file *event_file;
ssize_t ret;
char *buf;
if (!cnt)
return 0;
if (cnt >= PAGE_SIZE)
return -EINVAL;
buf = memdup_user_nul(ubuf, cnt);
if (IS_ERR(buf))
return PTR_ERR(buf);
strim(buf);
mutex_lock(&event_mutex);
event_file = event_file_data(file);
if (unlikely(!event_file)) {
mutex_unlock(&event_mutex);
kfree(buf);
return -ENODEV;
}
ret = trigger_process_regex(event_file, buf);
mutex_unlock(&event_mutex);
kfree(buf);
if (ret < 0)
goto out;
*ppos += cnt;
ret = cnt;
out:
return ret;
}
static int event_trigger_regex_release(struct inode *inode, struct file *file)
{
mutex_lock(&event_mutex);
if (file->f_mode & FMODE_READ)
seq_release(inode, file);
mutex_unlock(&event_mutex);
return 0;
}
static ssize_t
event_trigger_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return event_trigger_regex_write(filp, ubuf, cnt, ppos);
}
static int
event_trigger_open(struct inode *inode, struct file *filp)
{
/* 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;
list_for_each_entry_rcu(data, &file->triggers, list) {
if (data->filter || event_command_post_trigger(data->cmd_ops) ||
event_command_needs_rec(data->cmd_ops)) {
set_cond = true;
break;
}
}
if (set_cond)
set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
else
clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
}
/**
* register_trigger - Generic event_command @reg implementation
* @glob: The raw string used to register the trigger
* @ops: The trigger ops associated with the trigger
* @data: Trigger-specific data to associate with the trigger
* @file: The trace_event_file associated with the event
*
* Common implementation for event trigger registration.
*
* Usually used directly as the @reg method in event command
* implementations.
*
* Return: 0 on success, errno otherwise
*/
static int register_trigger(char *glob, struct event_trigger_ops *ops,
struct event_trigger_data *data,
struct trace_event_file *file)
{
struct event_trigger_data *test;
int ret = 0;
list_for_each_entry_rcu(test, &file->triggers, list) {
if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
ret = -EEXIST;
goto out;
}
}
if (data->ops->init) {
ret = data->ops->init(data->ops, data);
if (ret < 0)
goto out;
}
list_add_rcu(&data->list, &file->triggers);
ret++;
update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
ret--;
}
out:
return ret;
}
/**
* unregister_trigger - Generic event_command @unreg implementation
* @glob: The raw string used to register the trigger
* @ops: The trigger ops associated with the trigger
* @test: Trigger-specific data used to find the trigger to remove
* @file: The trace_event_file associated with the event
*
* Common implementation for event trigger unregistration.
*
* Usually used directly as the @unreg method in event command
* implementations.
*/
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;
list_for_each_entry_rcu(data, &file->triggers, list) {
if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
unregistered = true;
list_del_rcu(&data->list);
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
break;
}
}
if (unregistered && data->ops->free)
data->ops->free(data->ops, data);
}
/**
* event_trigger_callback - Generic event_command @func implementation
* @cmd_ops: The command ops, used for trigger registration
* @file: The trace_event_file associated with the event
* @glob: The raw string used to register the trigger
* @cmd: The cmd portion of the string used to register the trigger
* @param: The params portion of the string used to register the trigger
*
* Common implementation for event command parsing and trigger
* instantiation.
*
* Usually used directly as the @func method in event command
* implementations.
*
* Return: 0 on success, errno otherwise
*/
static int
event_trigger_callback(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param)
{
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
char *trigger = NULL;
char *number;
int ret;
/* separate the trigger from the filter (t:n [if filter]) */
if (param && isdigit(param[0]))
trigger = strsep(&param, " \t");
trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
ret = -ENOMEM;
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
if (!trigger_data)
goto out;
trigger_data->count = -1;
trigger_data->ops = trigger_ops;
trigger_data->cmd_ops = cmd_ops;
trigger_data->private_data = file;
INIT_LIST_HEAD(&trigger_data->list);
INIT_LIST_HEAD(&trigger_data->named_list);
if (glob[0] == '!') {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
kfree(trigger_data);
ret = 0;
goto out;
}
if (trigger) {
number = strsep(&trigger, ":");
ret = -EINVAL;
if (!strlen(number))
goto out_free;
/*
* We use the callback data field (which is a pointer)
* as our counter.
*/
ret = kstrtoul(number, 0, &trigger_data->count);
if (ret)
goto out_free;
}
if (!param) /* if param is non-empty, it's supposed to be a filter */
goto out_reg;
if (!cmd_ops->set_filter)
goto out_reg;
ret = cmd_ops->set_filter(param, trigger_data, file);
if (ret < 0)
goto out_free;
out_reg:
/* 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)
{
int ret = register_trigger(glob, ops, data, file);
if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
unregister_trigger(glob, ops, data, file);
ret = 0;
}
return ret;
}
static int
snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
struct event_trigger_data *data)
{
return event_trigger_print("snapshot", m, (void *)data->count,
data->filter_str);
}
static struct event_trigger_ops snapshot_trigger_ops = {
.func = snapshot_trigger,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops snapshot_count_trigger_ops = {
.func = snapshot_count_trigger,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops *
snapshot_get_trigger_ops(char *cmd, char *param)
{
return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
}
static struct event_command trigger_snapshot_cmd = {
.name = "snapshot",
.trigger_type = ETT_SNAPSHOT,
.func = event_trigger_callback,
.reg = register_snapshot_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = snapshot_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static __init int register_trigger_snapshot_cmd(void)
{
int ret;
ret = register_event_command(&trigger_snapshot_cmd);
WARN_ON(ret < 0);
return ret;
}
#else
static __init int register_trigger_snapshot_cmd(void) { return 0; }
#endif /* CONFIG_TRACER_SNAPSHOT */
#ifdef CONFIG_STACKTRACE
#ifdef CONFIG_UNWINDER_ORC
/* Skip 2:
* event_triggers_post_call()
* trace_event_raw_event_xxx()
*/
# define STACK_SKIP 2
#else
/*
* Skip 4:
* stacktrace_trigger()
* event_triggers_post_call()
* trace_event_buffer_commit()
* trace_event_raw_event_xxx()
*/
#define STACK_SKIP 4
#endif
static void
stacktrace_trigger(struct event_trigger_data *data, void *rec,
struct ring_buffer_event *event)
{
trace_dump_stack(STACK_SKIP);
}
static void
stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
struct ring_buffer_event *event)
{
if (!data->count)
return;
if (data->count != -1)
(data->count)--;
stacktrace_trigger(data, rec, event);
}
static int
stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
struct event_trigger_data *data)
{
return event_trigger_print("stacktrace", m, (void *)data->count,
data->filter_str);
}
static struct event_trigger_ops stacktrace_trigger_ops = {
.func = stacktrace_trigger,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops stacktrace_count_trigger_ops = {
.func = stacktrace_count_trigger,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops *
stacktrace_get_trigger_ops(char *cmd, char *param)
{
return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
}
static struct event_command trigger_stacktrace_cmd = {
.name = "stacktrace",
.trigger_type = ETT_STACKTRACE,
.flags = EVENT_CMD_FL_POST_TRIGGER,
.func = event_trigger_callback,
.reg = register_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = stacktrace_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static __init int register_trigger_stacktrace_cmd(void)
{
int ret;
ret = register_event_command(&trigger_stacktrace_cmd);
WARN_ON(ret < 0);
return ret;
}
#else
static __init int register_trigger_stacktrace_cmd(void) { return 0; }
#endif /* CONFIG_STACKTRACE */
static __init void unregister_trigger_traceon_traceoff_cmds(void)
{
unregister_event_command(&trigger_traceon_cmd);
unregister_event_command(&trigger_traceoff_cmd);
}
static void
event_enable_trigger(struct event_trigger_data *data, void *rec,
struct ring_buffer_event *event)
{
struct enable_trigger_data *enable_data = data->private_data;
if (enable_data->enable)
clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
else
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
}
static void
event_enable_count_trigger(struct event_trigger_data *data, void *rec,
struct ring_buffer_event *event)
{
struct enable_trigger_data *enable_data = data->private_data;
if (!data->count)
return;
/* Skip if the event is in a state we want to switch to */
if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
return;
if (data->count != -1)
(data->count)--;
event_enable_trigger(data, rec, event);
}
int event_enable_trigger_print(struct seq_file *m,
struct event_trigger_ops *ops,
struct event_trigger_data *data)
{
struct enable_trigger_data *enable_data = data->private_data;
seq_printf(m, "%s:%s:%s",
enable_data->hist ?
(enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
(enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
enable_data->file->event_call->class->system,
trace_event_name(enable_data->file->event_call));
if (data->count == -1)
seq_puts(m, ":unlimited");
else
seq_printf(m, ":count=%ld", data->count);
if (data->filter_str)
seq_printf(m, " if %s\n", data->filter_str);
else
seq_putc(m, '\n');
return 0;
}
void event_enable_trigger_free(struct event_trigger_ops *ops,
struct event_trigger_data *data)
{
struct enable_trigger_data *enable_data = data->private_data;
if (WARN_ON_ONCE(data->ref <= 0))
return;
data->ref--;
if (!data->ref) {
/* Remove the SOFT_MODE flag */
trace_event_enable_disable(enable_data->file, 0, 1);
module_put(enable_data->file->event_call->mod);
trigger_data_free(data);
kfree(enable_data);
}
}
static struct event_trigger_ops event_enable_trigger_ops = {
.func = event_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_enable_count_trigger_ops = {
.func = event_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_disable_trigger_ops = {
.func = event_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_disable_count_trigger_ops = {
.func = event_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
int event_enable_trigger_func(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param)
{
struct trace_event_file *event_enable_file;
struct enable_trigger_data *enable_data;
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
struct trace_array *tr = file->tr;
const char *system;
const char *event;
bool hist = false;
char *trigger;
char *number;
bool enable;
int ret;
if (!param)
return -EINVAL;
/* separate the trigger from the filter (s:e:n [if filter]) */
trigger = strsep(&param, " \t");
if (!trigger)
return -EINVAL;
system = strsep(&trigger, ":");
if (!trigger)
return -EINVAL;
event = strsep(&trigger, ":");
ret = -EINVAL;
event_enable_file = find_event_file(tr, system, event);
if (!event_enable_file)
goto out;
#ifdef CONFIG_HIST_TRIGGERS
hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
(strcmp(cmd, DISABLE_HIST_STR) == 0));
enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
(strcmp(cmd, ENABLE_HIST_STR) == 0));
#else
enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
#endif
trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
ret = -ENOMEM;
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
if (!trigger_data)
goto out;
enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
if (!enable_data) {
kfree(trigger_data);
goto out;
}
trigger_data->count = -1;
trigger_data->ops = trigger_ops;
trigger_data->cmd_ops = cmd_ops;
INIT_LIST_HEAD(&trigger_data->list);
RCU_INIT_POINTER(trigger_data->filter, NULL);
enable_data->hist = hist;
enable_data->enable = enable;
enable_data->file = event_enable_file;
trigger_data->private_data = enable_data;
if (glob[0] == '!') {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
kfree(trigger_data);
kfree(enable_data);
ret = 0;
goto out;
}
/* 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;
list_for_each_entry_rcu(test, &file->triggers, list) {
test_enable_data = test->private_data;
if (test_enable_data &&
(test->cmd_ops->trigger_type ==
data->cmd_ops->trigger_type) &&
(test_enable_data->file == enable_data->file)) {
ret = -EEXIST;
goto out;
}
}
if (data->ops->init) {
ret = data->ops->init(data->ops, data);
if (ret < 0)
goto out;
}
list_add_rcu(&data->list, &file->triggers);
ret++;
update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
ret--;
}
out:
return ret;
}
void event_enable_unregister_trigger(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *test,
struct trace_event_file *file)
{
struct enable_trigger_data *test_enable_data = test->private_data;
struct enable_trigger_data *enable_data;
struct event_trigger_data *data;
bool unregistered = false;
list_for_each_entry_rcu(data, &file->triggers, list) {
enable_data = data->private_data;
if (enable_data &&
(data->cmd_ops->trigger_type ==
test->cmd_ops->trigger_type) &&
(enable_data->file == test_enable_data->file)) {
unregistered = true;
list_del_rcu(&data->list);
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
break;
}
}
if (unregistered && data->ops->free)
data->ops->free(data->ops, data);
}
static struct event_trigger_ops *
event_enable_get_trigger_ops(char *cmd, char *param)
{
struct event_trigger_ops *ops;
bool enable;
#ifdef CONFIG_HIST_TRIGGERS
enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
(strcmp(cmd, ENABLE_HIST_STR) == 0));
#else
enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
#endif
if (enable)
ops = param ? &event_enable_count_trigger_ops :
&event_enable_trigger_ops;
else
ops = param ? &event_disable_count_trigger_ops :
&event_disable_trigger_ops;
return ops;
}
static struct event_command trigger_enable_cmd = {
.name = ENABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
.func = event_enable_trigger_func,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.get_trigger_ops = event_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static struct event_command trigger_disable_cmd = {
.name = DISABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
.func = event_enable_trigger_func,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.get_trigger_ops = event_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static __init void unregister_trigger_enable_disable_cmds(void)
{
unregister_event_command(&trigger_enable_cmd);
unregister_event_command(&trigger_disable_cmd);
}
static __init int register_trigger_enable_disable_cmds(void)
{
int ret;
ret = register_event_command(&trigger_enable_cmd);
if (WARN_ON(ret < 0))
return ret;
ret = register_event_command(&trigger_disable_cmd);
if (WARN_ON(ret < 0))
unregister_trigger_enable_disable_cmds();
return ret;
}
static __init int register_trigger_traceon_traceoff_cmds(void)
{
int ret;
ret = register_event_command(&trigger_traceon_cmd);
if (WARN_ON(ret < 0))
return ret;
ret = register_event_command(&trigger_traceoff_cmd);
if (WARN_ON(ret < 0))
unregister_trigger_traceon_traceoff_cmds();
return ret;
}
__init int register_trigger_cmds(void)
{
register_trigger_traceon_traceoff_cmds();
register_trigger_snapshot_cmd();
register_trigger_stacktrace_cmd();
register_trigger_enable_disable_cmds();
register_trigger_hist_enable_disable_cmds();
register_trigger_hist_cmd();
return 0;
}