linux/kernel/trace/trace_events.c
Steven Rostedt c5e4e19271 tracing: add trace name and id to event formats
To be able to identify the trace in the binary format output, the
id of the trace event (which is dynamically assigned) must also be listed.

This patch adds the name of the trace point as well as the id assigned.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-02 15:10:02 -05:00

731 lines
14 KiB
C

/*
* event tracer
*
* Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* - Added format output of fields of the trace point.
* This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
*
*/
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include "trace_output.h"
#define TRACE_SYSTEM "TRACE_SYSTEM"
static DEFINE_MUTEX(event_mutex);
#define events_for_each(event) \
for (event = __start_ftrace_events; \
(unsigned long)event < (unsigned long)__stop_ftrace_events; \
event++)
void event_trace_printk(unsigned long ip, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
tracing_record_cmdline(current);
trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
va_end(ap);
}
static void ftrace_clear_events(void)
{
struct ftrace_event_call *call = (void *)__start_ftrace_events;
while ((unsigned long)call < (unsigned long)__stop_ftrace_events) {
if (call->enabled) {
call->enabled = 0;
call->unregfunc();
}
call++;
}
}
static void ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
switch (enable) {
case 0:
if (call->enabled) {
call->enabled = 0;
call->unregfunc();
}
if (call->raw_enabled) {
call->raw_enabled = 0;
call->raw_unreg();
}
break;
case 1:
if (!call->enabled &&
(call->type & TRACE_EVENT_TYPE_PRINTF)) {
call->enabled = 1;
call->regfunc();
}
if (!call->raw_enabled &&
(call->type & TRACE_EVENT_TYPE_RAW)) {
call->raw_enabled = 1;
call->raw_reg();
}
break;
}
}
static int ftrace_set_clr_event(char *buf, int set)
{
struct ftrace_event_call *call = __start_ftrace_events;
char *event = NULL, *sub = NULL, *match;
int ret = -EINVAL;
/*
* The buf format can be <subsystem>:<event-name>
* *:<event-name> means any event by that name.
* :<event-name> is the same.
*
* <subsystem>:* means all events in that subsystem
* <subsystem>: means the same.
*
* <name> (no ':') means all events in a subsystem with
* the name <name> or any event that matches <name>
*/
match = strsep(&buf, ":");
if (buf) {
sub = match;
event = buf;
match = NULL;
if (!strlen(sub) || strcmp(sub, "*") == 0)
sub = NULL;
if (!strlen(event) || strcmp(event, "*") == 0)
event = NULL;
}
mutex_lock(&event_mutex);
events_for_each(call) {
if (!call->name)
continue;
if (match &&
strcmp(match, call->name) != 0 &&
strcmp(match, call->system) != 0)
continue;
if (sub && strcmp(sub, call->system) != 0)
continue;
if (event && strcmp(event, call->name) != 0)
continue;
ftrace_event_enable_disable(call, set);
ret = 0;
}
mutex_unlock(&event_mutex);
return ret;
}
/* 128 should be much more than enough */
#define EVENT_BUF_SIZE 127
static ssize_t
ftrace_event_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
size_t read = 0;
int i, set = 1;
ssize_t ret;
char *buf;
char ch;
if (!cnt || cnt < 0)
return 0;
ret = get_user(ch, ubuf++);
if (ret)
return ret;
read++;
cnt--;
/* skip white space */
while (cnt && isspace(ch)) {
ret = get_user(ch, ubuf++);
if (ret)
return ret;
read++;
cnt--;
}
/* Only white space found? */
if (isspace(ch)) {
file->f_pos += read;
ret = read;
return ret;
}
buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (cnt > EVENT_BUF_SIZE)
cnt = EVENT_BUF_SIZE;
i = 0;
while (cnt && !isspace(ch)) {
if (!i && ch == '!')
set = 0;
else
buf[i++] = ch;
ret = get_user(ch, ubuf++);
if (ret)
goto out_free;
read++;
cnt--;
}
buf[i] = 0;
file->f_pos += read;
ret = ftrace_set_clr_event(buf, set);
if (ret)
goto out_free;
ret = read;
out_free:
kfree(buf);
return ret;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_event_call *call = m->private;
struct ftrace_event_call *next = call;
(*pos)++;
if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
return NULL;
m->private = ++next;
return call;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
return t_next(m, NULL, pos);
}
static void *
s_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_event_call *call = m->private;
struct ftrace_event_call *next;
(*pos)++;
retry:
if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
return NULL;
if (!call->enabled) {
call++;
goto retry;
}
next = call;
m->private = ++next;
return call;
}
static void *s_start(struct seq_file *m, loff_t *pos)
{
return s_next(m, NULL, pos);
}
static int t_show(struct seq_file *m, void *v)
{
struct ftrace_event_call *call = v;
if (strcmp(call->system, TRACE_SYSTEM) != 0)
seq_printf(m, "%s:", call->system);
seq_printf(m, "%s\n", call->name);
return 0;
}
static void t_stop(struct seq_file *m, void *p)
{
}
static int
ftrace_event_seq_open(struct inode *inode, struct file *file)
{
int ret;
const struct seq_operations *seq_ops;
if ((file->f_mode & FMODE_WRITE) &&
!(file->f_flags & O_APPEND))
ftrace_clear_events();
seq_ops = inode->i_private;
ret = seq_open(file, seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = __start_ftrace_events;
}
return ret;
}
static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char *buf;
if (call->enabled || call->raw_enabled)
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[64];
unsigned long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
return ret;
switch (val) {
case 0:
case 1:
mutex_lock(&event_mutex);
ftrace_event_enable_disable(call, val);
mutex_unlock(&event_mutex);
break;
default:
return -EINVAL;
}
*ppos += cnt;
return cnt;
}
static ssize_t
event_type_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[16];
int r = 0;
if (call->type & TRACE_EVENT_TYPE_PRINTF)
r += sprintf(buf, "printf\n");
if (call->type & TRACE_EVENT_TYPE_RAW)
r += sprintf(buf+r, "raw\n");
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static ssize_t
event_type_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[64];
/*
* If there's only one type, we can't change it.
* And currently we always have printf type, and we
* may or may not have raw type.
*
* This is a redundant check, the file should be read
* only if this is the case anyway.
*/
if (!call->raw_init)
return -EPERM;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
if (!strncmp(buf, "printf", 6) &&
(!buf[6] || isspace(buf[6]))) {
call->type = TRACE_EVENT_TYPE_PRINTF;
/*
* If raw enabled, the disable it and enable
* printf type.
*/
if (call->raw_enabled) {
call->raw_enabled = 0;
call->raw_unreg();
call->enabled = 1;
call->regfunc();
}
} else if (!strncmp(buf, "raw", 3) &&
(!buf[3] || isspace(buf[3]))) {
call->type = TRACE_EVENT_TYPE_RAW;
/*
* If printf enabled, the disable it and enable
* raw type.
*/
if (call->enabled) {
call->enabled = 0;
call->unregfunc();
call->raw_enabled = 1;
call->raw_reg();
}
} else
return -EINVAL;
*ppos += cnt;
return cnt;
}
static ssize_t
event_available_types_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[16];
int r = 0;
r += sprintf(buf, "printf\n");
if (call->raw_init)
r += sprintf(buf+r, "raw\n");
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
#undef FIELD
#define FIELD(type, name) \
#type, #name, offsetof(typeof(field), name), sizeof(field.name)
static int trace_write_header(struct trace_seq *s)
{
struct trace_entry field;
/* struct trace_entry */
return trace_seq_printf(s,
"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
"\n",
FIELD(unsigned char, type),
FIELD(unsigned char, flags),
FIELD(unsigned char, preempt_count),
FIELD(int, pid),
FIELD(int, tgid));
}
static ssize_t
event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
struct trace_seq *s;
char *buf;
int r;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
if (*ppos)
return 0;
/* If any of the first writes fail, so will the show_format. */
trace_seq_printf(s, "name: %s\n", call->name);
trace_seq_printf(s, "ID: %d\n", call->id);
trace_seq_printf(s, "format:\n");
trace_write_header(s);
r = call->show_format(s);
if (!r) {
/*
* ug! The format output is bigger than a PAGE!!
*/
buf = "FORMAT TOO BIG\n";
r = simple_read_from_buffer(ubuf, cnt, ppos,
buf, strlen(buf));
goto out;
}
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, s->len);
out:
kfree(s);
return r;
}
static const struct seq_operations show_event_seq_ops = {
.start = t_start,
.next = t_next,
.show = t_show,
.stop = t_stop,
};
static const struct seq_operations show_set_event_seq_ops = {
.start = s_start,
.next = s_next,
.show = t_show,
.stop = t_stop,
};
static const struct file_operations ftrace_avail_fops = {
.open = ftrace_event_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations ftrace_set_event_fops = {
.open = ftrace_event_seq_open,
.read = seq_read,
.write = ftrace_event_write,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations ftrace_enable_fops = {
.open = tracing_open_generic,
.read = event_enable_read,
.write = event_enable_write,
};
static const struct file_operations ftrace_type_fops = {
.open = tracing_open_generic,
.read = event_type_read,
.write = event_type_write,
};
static const struct file_operations ftrace_available_types_fops = {
.open = tracing_open_generic,
.read = event_available_types_read,
};
static const struct file_operations ftrace_event_format_fops = {
.open = tracing_open_generic,
.read = event_format_read,
};
static struct dentry *event_trace_events_dir(void)
{
static struct dentry *d_tracer;
static struct dentry *d_events;
if (d_events)
return d_events;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return NULL;
d_events = debugfs_create_dir("events", d_tracer);
if (!d_events)
pr_warning("Could not create debugfs "
"'events' directory\n");
return d_events;
}
struct event_subsystem {
struct list_head list;
const char *name;
struct dentry *entry;
};
static LIST_HEAD(event_subsystems);
static struct dentry *
event_subsystem_dir(const char *name, struct dentry *d_events)
{
struct event_subsystem *system;
/* First see if we did not already create this dir */
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0)
return system->entry;
}
/* need to create new entry */
system = kmalloc(sizeof(*system), GFP_KERNEL);
if (!system) {
pr_warning("No memory to create event subsystem %s\n",
name);
return d_events;
}
system->entry = debugfs_create_dir(name, d_events);
if (!system->entry) {
pr_warning("Could not create event subsystem %s\n",
name);
kfree(system);
return d_events;
}
system->name = name;
list_add(&system->list, &event_subsystems);
return system->entry;
}
static int
event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
{
struct dentry *entry;
int ret;
/*
* If the trace point header did not define TRACE_SYSTEM
* then the system would be called "TRACE_SYSTEM".
*/
if (strcmp(call->system, "TRACE_SYSTEM") != 0)
d_events = event_subsystem_dir(call->system, d_events);
if (call->raw_init) {
ret = call->raw_init();
if (ret < 0) {
pr_warning("Could not initialize trace point"
" events/%s\n", call->name);
return ret;
}
}
/* default the output to printf */
call->type = TRACE_EVENT_TYPE_PRINTF;
call->dir = debugfs_create_dir(call->name, d_events);
if (!call->dir) {
pr_warning("Could not create debugfs "
"'%s' directory\n", call->name);
return -1;
}
entry = debugfs_create_file("enable", 0644, call->dir, call,
&ftrace_enable_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'%s/enable' entry\n", call->name);
/* Only let type be writable, if we can change it */
entry = debugfs_create_file("type",
call->raw_init ? 0644 : 0444,
call->dir, call,
&ftrace_type_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'%s/type' entry\n", call->name);
entry = debugfs_create_file("available_types", 0444, call->dir, call,
&ftrace_available_types_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'%s/available_types' entry\n", call->name);
/* A trace may not want to export its format */
if (!call->show_format)
return 0;
entry = debugfs_create_file("format", 0444, call->dir, call,
&ftrace_event_format_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'%s/format' entry\n", call->name);
return 0;
}
static __init int event_trace_init(void)
{
struct ftrace_event_call *call = __start_ftrace_events;
struct dentry *d_tracer;
struct dentry *entry;
struct dentry *d_events;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return 0;
entry = debugfs_create_file("available_events", 0444, d_tracer,
(void *)&show_event_seq_ops,
&ftrace_avail_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'available_events' entry\n");
entry = debugfs_create_file("set_event", 0644, d_tracer,
(void *)&show_set_event_seq_ops,
&ftrace_set_event_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'set_event' entry\n");
d_events = event_trace_events_dir();
if (!d_events)
return 0;
events_for_each(call) {
/* The linker may leave blanks */
if (!call->name)
continue;
event_create_dir(call, d_events);
}
return 0;
}
fs_initcall(event_trace_init);