linux-stable/kernel/trace/trace_events_synth.c
Axel Rasmussen 6107742d15 tracing: support "bool" type in synthetic trace events
It's common [1] to define tracepoint fields as "bool" when they contain
a true / false value. Currently, defining a synthetic event with a
"bool" field yields EINVAL. It's possible to work around this by using
e.g. u8 (assuming sizeof(bool) is 1, and bool is unsigned; if either of
these properties don't match, you get EINVAL [2]).

Supporting "bool" explicitly makes hooking this up easier and more
portable for userspace.

[1]: grep -r "bool" include/trace/events/
[2]: check_synth_field() in kernel/trace/trace_events_hist.c

Link: https://lkml.kernel.org/r/20201009220524.485102-2-axelrasmussen@google.com

Acked-by: Michel Lespinasse <walken@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-10-15 12:01:14 -04:00

2098 lines
50 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* trace_events_synth - synthetic trace events
*
* Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
*/
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/rculist.h>
#include <linux/tracefs.h>
/* for gfp flag names */
#include <linux/trace_events.h>
#include <trace/events/mmflags.h>
#include "trace_synth.h"
#undef ERRORS
#define ERRORS \
C(BAD_NAME, "Illegal name"), \
C(CMD_INCOMPLETE, "Incomplete command"), \
C(EVENT_EXISTS, "Event already exists"), \
C(TOO_MANY_FIELDS, "Too many fields"), \
C(INCOMPLETE_TYPE, "Incomplete type"), \
C(INVALID_TYPE, "Invalid type"), \
C(INVALID_FIELD, "Invalid field"), \
C(CMD_TOO_LONG, "Command too long"),
#undef C
#define C(a, b) SYNTH_ERR_##a
enum { ERRORS };
#undef C
#define C(a, b) b
static const char *err_text[] = { ERRORS };
static char last_cmd[MAX_FILTER_STR_VAL];
static int errpos(const char *str)
{
return err_pos(last_cmd, str);
}
static void last_cmd_set(char *str)
{
if (!str)
return;
strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
}
static void synth_err(u8 err_type, u8 err_pos)
{
tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
err_type, err_pos);
}
static int create_synth_event(int argc, const char **argv);
static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
static int synth_event_release(struct dyn_event *ev);
static bool synth_event_is_busy(struct dyn_event *ev);
static bool synth_event_match(const char *system, const char *event,
int argc, const char **argv, struct dyn_event *ev);
static struct dyn_event_operations synth_event_ops = {
.create = create_synth_event,
.show = synth_event_show,
.is_busy = synth_event_is_busy,
.free = synth_event_release,
.match = synth_event_match,
};
static bool is_synth_event(struct dyn_event *ev)
{
return ev->ops == &synth_event_ops;
}
static struct synth_event *to_synth_event(struct dyn_event *ev)
{
return container_of(ev, struct synth_event, devent);
}
static bool synth_event_is_busy(struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
return event->ref != 0;
}
static bool synth_event_match(const char *system, const char *event,
int argc, const char **argv, struct dyn_event *ev)
{
struct synth_event *sev = to_synth_event(ev);
return strcmp(sev->name, event) == 0 &&
(!system || strcmp(system, SYNTH_SYSTEM) == 0);
}
struct synth_trace_event {
struct trace_entry ent;
u64 fields[];
};
static int synth_event_define_fields(struct trace_event_call *call)
{
struct synth_trace_event trace;
int offset = offsetof(typeof(trace), fields);
struct synth_event *event = call->data;
unsigned int i, size, n_u64;
char *name, *type;
bool is_signed;
int ret = 0;
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
size = event->fields[i]->size;
is_signed = event->fields[i]->is_signed;
type = event->fields[i]->type;
name = event->fields[i]->name;
ret = trace_define_field(call, type, name, offset, size,
is_signed, FILTER_OTHER);
if (ret)
break;
event->fields[i]->offset = n_u64;
if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
offset += STR_VAR_LEN_MAX;
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
offset += sizeof(u64);
n_u64++;
}
}
event->n_u64 = n_u64;
return ret;
}
static bool synth_field_signed(char *type)
{
if (str_has_prefix(type, "u"))
return false;
if (strcmp(type, "gfp_t") == 0)
return false;
return true;
}
static int synth_field_is_string(char *type)
{
if (strstr(type, "char[") != NULL)
return true;
return false;
}
static int synth_field_string_size(char *type)
{
char buf[4], *end, *start;
unsigned int len;
int size, err;
start = strstr(type, "char[");
if (start == NULL)
return -EINVAL;
start += sizeof("char[") - 1;
end = strchr(type, ']');
if (!end || end < start || type + strlen(type) > end + 1)
return -EINVAL;
len = end - start;
if (len > 3)
return -EINVAL;
if (len == 0)
return 0; /* variable-length string */
strncpy(buf, start, len);
buf[len] = '\0';
err = kstrtouint(buf, 0, &size);
if (err)
return err;
if (size > STR_VAR_LEN_MAX)
return -EINVAL;
return size;
}
static int synth_field_size(char *type)
{
int size = 0;
if (strcmp(type, "s64") == 0)
size = sizeof(s64);
else if (strcmp(type, "u64") == 0)
size = sizeof(u64);
else if (strcmp(type, "s32") == 0)
size = sizeof(s32);
else if (strcmp(type, "u32") == 0)
size = sizeof(u32);
else if (strcmp(type, "s16") == 0)
size = sizeof(s16);
else if (strcmp(type, "u16") == 0)
size = sizeof(u16);
else if (strcmp(type, "s8") == 0)
size = sizeof(s8);
else if (strcmp(type, "u8") == 0)
size = sizeof(u8);
else if (strcmp(type, "char") == 0)
size = sizeof(char);
else if (strcmp(type, "unsigned char") == 0)
size = sizeof(unsigned char);
else if (strcmp(type, "int") == 0)
size = sizeof(int);
else if (strcmp(type, "unsigned int") == 0)
size = sizeof(unsigned int);
else if (strcmp(type, "long") == 0)
size = sizeof(long);
else if (strcmp(type, "unsigned long") == 0)
size = sizeof(unsigned long);
else if (strcmp(type, "bool") == 0)
size = sizeof(bool);
else if (strcmp(type, "pid_t") == 0)
size = sizeof(pid_t);
else if (strcmp(type, "gfp_t") == 0)
size = sizeof(gfp_t);
else if (synth_field_is_string(type))
size = synth_field_string_size(type);
return size;
}
static const char *synth_field_fmt(char *type)
{
const char *fmt = "%llu";
if (strcmp(type, "s64") == 0)
fmt = "%lld";
else if (strcmp(type, "u64") == 0)
fmt = "%llu";
else if (strcmp(type, "s32") == 0)
fmt = "%d";
else if (strcmp(type, "u32") == 0)
fmt = "%u";
else if (strcmp(type, "s16") == 0)
fmt = "%d";
else if (strcmp(type, "u16") == 0)
fmt = "%u";
else if (strcmp(type, "s8") == 0)
fmt = "%d";
else if (strcmp(type, "u8") == 0)
fmt = "%u";
else if (strcmp(type, "char") == 0)
fmt = "%d";
else if (strcmp(type, "unsigned char") == 0)
fmt = "%u";
else if (strcmp(type, "int") == 0)
fmt = "%d";
else if (strcmp(type, "unsigned int") == 0)
fmt = "%u";
else if (strcmp(type, "long") == 0)
fmt = "%ld";
else if (strcmp(type, "unsigned long") == 0)
fmt = "%lu";
else if (strcmp(type, "bool") == 0)
fmt = "%d";
else if (strcmp(type, "pid_t") == 0)
fmt = "%d";
else if (strcmp(type, "gfp_t") == 0)
fmt = "%x";
else if (synth_field_is_string(type))
fmt = "%.*s";
return fmt;
}
static void print_synth_event_num_val(struct trace_seq *s,
char *print_fmt, char *name,
int size, u64 val, char *space)
{
switch (size) {
case 1:
trace_seq_printf(s, print_fmt, name, (u8)val, space);
break;
case 2:
trace_seq_printf(s, print_fmt, name, (u16)val, space);
break;
case 4:
trace_seq_printf(s, print_fmt, name, (u32)val, space);
break;
default:
trace_seq_printf(s, print_fmt, name, val, space);
break;
}
}
static enum print_line_t print_synth_event(struct trace_iterator *iter,
int flags,
struct trace_event *event)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
struct synth_trace_event *entry;
struct synth_event *se;
unsigned int i, n_u64;
char print_fmt[32];
const char *fmt;
entry = (struct synth_trace_event *)iter->ent;
se = container_of(event, struct synth_event, call.event);
trace_seq_printf(s, "%s: ", se->name);
for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
if (trace_seq_has_overflowed(s))
goto end;
fmt = synth_field_fmt(se->fields[i]->type);
/* parameter types */
if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
trace_seq_printf(s, "%s ", fmt);
snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
/* parameter values */
if (se->fields[i]->is_string) {
if (se->fields[i]->is_dynamic) {
u32 offset, data_offset;
char *str_field;
offset = (u32)entry->fields[n_u64];
data_offset = offset & 0xffff;
str_field = (char *)entry + data_offset;
trace_seq_printf(s, print_fmt, se->fields[i]->name,
STR_VAR_LEN_MAX,
str_field,
i == se->n_fields - 1 ? "" : " ");
n_u64++;
} else {
trace_seq_printf(s, print_fmt, se->fields[i]->name,
STR_VAR_LEN_MAX,
(char *)&entry->fields[n_u64],
i == se->n_fields - 1 ? "" : " ");
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
}
} else {
struct trace_print_flags __flags[] = {
__def_gfpflag_names, {-1, NULL} };
char *space = (i == se->n_fields - 1 ? "" : " ");
print_synth_event_num_val(s, print_fmt,
se->fields[i]->name,
se->fields[i]->size,
entry->fields[n_u64],
space);
if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
trace_seq_puts(s, " (");
trace_print_flags_seq(s, "|",
entry->fields[n_u64],
__flags);
trace_seq_putc(s, ')');
}
n_u64++;
}
}
end:
trace_seq_putc(s, '\n');
return trace_handle_return(s);
}
static struct trace_event_functions synth_event_funcs = {
.trace = print_synth_event
};
static unsigned int trace_string(struct synth_trace_event *entry,
struct synth_event *event,
char *str_val,
bool is_dynamic,
unsigned int data_size,
unsigned int *n_u64)
{
unsigned int len = 0;
char *str_field;
if (is_dynamic) {
u32 data_offset;
data_offset = offsetof(typeof(*entry), fields);
data_offset += event->n_u64 * sizeof(u64);
data_offset += data_size;
str_field = (char *)entry + data_offset;
len = strlen(str_val) + 1;
strscpy(str_field, str_val, len);
data_offset |= len << 16;
*(u32 *)&entry->fields[*n_u64] = data_offset;
(*n_u64)++;
} else {
str_field = (char *)&entry->fields[*n_u64];
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
(*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
}
return len;
}
static notrace void trace_event_raw_event_synth(void *__data,
u64 *var_ref_vals,
unsigned int *var_ref_idx)
{
unsigned int i, n_u64, val_idx, len, data_size = 0;
struct trace_event_file *trace_file = __data;
struct synth_trace_event *entry;
struct trace_event_buffer fbuffer;
struct trace_buffer *buffer;
struct synth_event *event;
int fields_size = 0;
event = trace_file->event_call->data;
if (trace_trigger_soft_disabled(trace_file))
return;
fields_size = event->n_u64 * sizeof(u64);
for (i = 0; i < event->n_dynamic_fields; i++) {
unsigned int field_pos = event->dynamic_fields[i]->field_pos;
char *str_val;
val_idx = var_ref_idx[field_pos];
str_val = (char *)(long)var_ref_vals[val_idx];
len = strlen(str_val) + 1;
fields_size += len;
}
/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
buffer = trace_file->tr->array_buffer.buffer;
ring_buffer_nest_start(buffer);
entry = trace_event_buffer_reserve(&fbuffer, trace_file,
sizeof(*entry) + fields_size);
if (!entry)
goto out;
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
val_idx = var_ref_idx[i];
if (event->fields[i]->is_string) {
char *str_val = (char *)(long)var_ref_vals[val_idx];
len = trace_string(entry, event, str_val,
event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = event->fields[i];
u64 val = var_ref_vals[val_idx];
switch (field->size) {
case 1:
*(u8 *)&entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&entry->fields[n_u64] = (u32)val;
break;
default:
entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
trace_event_buffer_commit(&fbuffer);
out:
ring_buffer_nest_end(buffer);
}
static void free_synth_event_print_fmt(struct trace_event_call *call)
{
if (call) {
kfree(call->print_fmt);
call->print_fmt = NULL;
}
}
static int __set_synth_event_print_fmt(struct synth_event *event,
char *buf, int len)
{
const char *fmt;
int pos = 0;
int i;
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < event->n_fields; i++) {
fmt = synth_field_fmt(event->fields[i]->type);
pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
event->fields[i]->name, fmt,
i == event->n_fields - 1 ? "" : ", ");
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < event->n_fields; i++) {
if (event->fields[i]->is_string &&
event->fields[i]->is_dynamic)
pos += snprintf(buf + pos, LEN_OR_ZERO,
", __get_str(%s)", event->fields[i]->name);
else
pos += snprintf(buf + pos, LEN_OR_ZERO,
", REC->%s", event->fields[i]->name);
}
#undef LEN_OR_ZERO
/* return the length of print_fmt */
return pos;
}
static int set_synth_event_print_fmt(struct trace_event_call *call)
{
struct synth_event *event = call->data;
char *print_fmt;
int len;
/* First: called with 0 length to calculate the needed length */
len = __set_synth_event_print_fmt(event, NULL, 0);
print_fmt = kmalloc(len + 1, GFP_KERNEL);
if (!print_fmt)
return -ENOMEM;
/* Second: actually write the @print_fmt */
__set_synth_event_print_fmt(event, print_fmt, len + 1);
call->print_fmt = print_fmt;
return 0;
}
static void free_synth_field(struct synth_field *field)
{
kfree(field->type);
kfree(field->name);
kfree(field);
}
static struct synth_field *parse_synth_field(int argc, const char **argv,
int *consumed)
{
struct synth_field *field;
const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
int len, ret = 0;
ssize_t size;
if (field_type[0] == ';')
field_type++;
if (!strcmp(field_type, "unsigned")) {
if (argc < 3) {
synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
return ERR_PTR(-EINVAL);
}
prefix = "unsigned ";
field_type = argv[1];
field_name = argv[2];
*consumed = 3;
} else {
field_name = argv[1];
*consumed = 2;
}
field = kzalloc(sizeof(*field), GFP_KERNEL);
if (!field)
return ERR_PTR(-ENOMEM);
len = strlen(field_name);
array = strchr(field_name, '[');
if (array)
len -= strlen(array);
else if (field_name[len - 1] == ';')
len--;
field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
if (!field->name) {
ret = -ENOMEM;
goto free;
}
if (!is_good_name(field->name)) {
synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
ret = -EINVAL;
goto free;
}
if (field_type[0] == ';')
field_type++;
len = strlen(field_type) + 1;
if (array) {
int l = strlen(array);
if (l && array[l - 1] == ';')
l--;
len += l;
}
if (prefix)
len += strlen(prefix);
field->type = kzalloc(len, GFP_KERNEL);
if (!field->type) {
ret = -ENOMEM;
goto free;
}
if (prefix)
strcat(field->type, prefix);
strcat(field->type, field_type);
if (array) {
strcat(field->type, array);
if (field->type[len - 1] == ';')
field->type[len - 1] = '\0';
}
size = synth_field_size(field->type);
if (size < 0) {
synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
ret = -EINVAL;
goto free;
} else if (size == 0) {
if (synth_field_is_string(field->type)) {
char *type;
type = kzalloc(sizeof("__data_loc ") + strlen(field->type) + 1, GFP_KERNEL);
if (!type) {
ret = -ENOMEM;
goto free;
}
strcat(type, "__data_loc ");
strcat(type, field->type);
kfree(field->type);
field->type = type;
field->is_dynamic = true;
size = sizeof(u64);
} else {
synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
ret = -EINVAL;
goto free;
}
}
field->size = size;
if (synth_field_is_string(field->type))
field->is_string = true;
field->is_signed = synth_field_signed(field->type);
out:
return field;
free:
free_synth_field(field);
field = ERR_PTR(ret);
goto out;
}
static void free_synth_tracepoint(struct tracepoint *tp)
{
if (!tp)
return;
kfree(tp->name);
kfree(tp);
}
static struct tracepoint *alloc_synth_tracepoint(char *name)
{
struct tracepoint *tp;
tp = kzalloc(sizeof(*tp), GFP_KERNEL);
if (!tp)
return ERR_PTR(-ENOMEM);
tp->name = kstrdup(name, GFP_KERNEL);
if (!tp->name) {
kfree(tp);
return ERR_PTR(-ENOMEM);
}
return tp;
}
struct synth_event *find_synth_event(const char *name)
{
struct dyn_event *pos;
struct synth_event *event;
for_each_dyn_event(pos) {
if (!is_synth_event(pos))
continue;
event = to_synth_event(pos);
if (strcmp(event->name, name) == 0)
return event;
}
return NULL;
}
static struct trace_event_fields synth_event_fields_array[] = {
{ .type = TRACE_FUNCTION_TYPE,
.define_fields = synth_event_define_fields },
{}
};
static int register_synth_event(struct synth_event *event)
{
struct trace_event_call *call = &event->call;
int ret = 0;
event->call.class = &event->class;
event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
if (!event->class.system) {
ret = -ENOMEM;
goto out;
}
event->tp = alloc_synth_tracepoint(event->name);
if (IS_ERR(event->tp)) {
ret = PTR_ERR(event->tp);
event->tp = NULL;
goto out;
}
INIT_LIST_HEAD(&call->class->fields);
call->event.funcs = &synth_event_funcs;
call->class->fields_array = synth_event_fields_array;
ret = register_trace_event(&call->event);
if (!ret) {
ret = -ENODEV;
goto out;
}
call->flags = TRACE_EVENT_FL_TRACEPOINT;
call->class->reg = trace_event_reg;
call->class->probe = trace_event_raw_event_synth;
call->data = event;
call->tp = event->tp;
ret = trace_add_event_call(call);
if (ret) {
pr_warn("Failed to register synthetic event: %s\n",
trace_event_name(call));
goto err;
}
ret = set_synth_event_print_fmt(call);
if (ret < 0) {
trace_remove_event_call(call);
goto err;
}
out:
return ret;
err:
unregister_trace_event(&call->event);
goto out;
}
static int unregister_synth_event(struct synth_event *event)
{
struct trace_event_call *call = &event->call;
int ret;
ret = trace_remove_event_call(call);
return ret;
}
static void free_synth_event(struct synth_event *event)
{
unsigned int i;
if (!event)
return;
for (i = 0; i < event->n_fields; i++)
free_synth_field(event->fields[i]);
kfree(event->fields);
kfree(event->dynamic_fields);
kfree(event->name);
kfree(event->class.system);
free_synth_tracepoint(event->tp);
free_synth_event_print_fmt(&event->call);
kfree(event);
}
static struct synth_event *alloc_synth_event(const char *name, int n_fields,
struct synth_field **fields)
{
unsigned int i, j, n_dynamic_fields = 0;
struct synth_event *event;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event) {
event = ERR_PTR(-ENOMEM);
goto out;
}
event->name = kstrdup(name, GFP_KERNEL);
if (!event->name) {
kfree(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
if (!event->fields) {
free_synth_event(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
for (i = 0; i < n_fields; i++)
if (fields[i]->is_dynamic)
n_dynamic_fields++;
if (n_dynamic_fields) {
event->dynamic_fields = kcalloc(n_dynamic_fields,
sizeof(*event->dynamic_fields),
GFP_KERNEL);
if (!event->dynamic_fields) {
free_synth_event(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
}
dyn_event_init(&event->devent, &synth_event_ops);
for (i = 0, j = 0; i < n_fields; i++) {
event->fields[i] = fields[i];
if (fields[i]->is_dynamic) {
event->dynamic_fields[j] = fields[i];
event->dynamic_fields[j]->field_pos = i;
event->dynamic_fields[j++] = fields[i];
event->n_dynamic_fields++;
}
}
event->n_fields = n_fields;
out:
return event;
}
static int synth_event_check_arg_fn(void *data)
{
struct dynevent_arg_pair *arg_pair = data;
int size;
size = synth_field_size((char *)arg_pair->lhs);
if (size == 0) {
if (strstr((char *)arg_pair->lhs, "["))
return 0;
}
return size ? 0 : -EINVAL;
}
/**
* synth_event_add_field - Add a new field to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @type: The type of the new field to add
* @name: The name of the new field to add
*
* Add a new field to a synthetic event cmd object. Field ordering is in
* the same order the fields are added.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
const char *name)
{
struct dynevent_arg_pair arg_pair;
int ret;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (!type || !name)
return -EINVAL;
dynevent_arg_pair_init(&arg_pair, 0, ';');
arg_pair.lhs = type;
arg_pair.rhs = name;
ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
if (ret)
return ret;
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
ret = -EINVAL;
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_field);
/**
* synth_event_add_field_str - Add a new field to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @type_name: The type and name of the new field to add, as a single string
*
* Add a new field to a synthetic event cmd object, as a single
* string. The @type_name string is expected to be of the form 'type
* name', which will be appended by ';'. No sanity checking is done -
* what's passed in is assumed to already be well-formed. Field
* ordering is in the same order the fields are added.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
{
struct dynevent_arg arg;
int ret;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (!type_name)
return -EINVAL;
dynevent_arg_init(&arg, ';');
arg.str = type_name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
ret = -EINVAL;
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_field_str);
/**
* synth_event_add_fields - Add multiple fields to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
*
* Add a new set of fields to a synthetic event cmd object. The event
* fields that will be defined for the event should be passed in as an
* array of struct synth_field_desc, and the number of elements in the
* array passed in as n_fields. Field ordering will retain the
* ordering given in the fields array.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_fields(struct dynevent_cmd *cmd,
struct synth_field_desc *fields,
unsigned int n_fields)
{
unsigned int i;
int ret = 0;
for (i = 0; i < n_fields; i++) {
if (fields[i].type == NULL || fields[i].name == NULL) {
ret = -EINVAL;
break;
}
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
if (ret)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_fields);
/**
* __synth_event_gen_cmd_start - Start a synthetic event command from arg list
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @name: The name of the synthetic event
* @mod: The module creating the event, NULL if not created from a module
* @args: Variable number of arg (pairs), one pair for each field
*
* NOTE: Users normally won't want to call this function directly, but
* rather use the synth_event_gen_cmd_start() wrapper, which
* automatically adds a NULL to the end of the arg list. If this
* function is used directly, make sure the last arg in the variable
* arg list is NULL.
*
* Generate a synthetic event command to be executed by
* synth_event_gen_cmd_end(). This function can be used to generate
* the complete command or only the first part of it; in the latter
* case, synth_event_add_field(), synth_event_add_field_str(), or
* synth_event_add_fields() can be used to add more fields following
* this.
*
* There should be an even number variable args, each pair consisting
* of a type followed by a field name.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
struct module *mod, ...)
{
struct dynevent_arg arg;
va_list args;
int ret;
cmd->event_name = name;
cmd->private_data = mod;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
dynevent_arg_init(&arg, 0);
arg.str = name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
va_start(args, mod);
for (;;) {
const char *type, *name;
type = va_arg(args, const char *);
if (!type)
break;
name = va_arg(args, const char *);
if (!name)
break;
if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
ret = -EINVAL;
break;
}
ret = synth_event_add_field(cmd, type, name);
if (ret)
break;
}
va_end(args);
return ret;
}
EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
/**
* synth_event_gen_cmd_array_start - Start synthetic event command from an array
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @name: The name of the synthetic event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
*
* Generate a synthetic event command to be executed by
* synth_event_gen_cmd_end(). This function can be used to generate
* the complete command or only the first part of it; in the latter
* case, synth_event_add_field(), synth_event_add_field_str(), or
* synth_event_add_fields() can be used to add more fields following
* this.
*
* The event fields that will be defined for the event should be
* passed in as an array of struct synth_field_desc, and the number of
* elements in the array passed in as n_fields. Field ordering will
* retain the ordering given in the fields array.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
struct module *mod,
struct synth_field_desc *fields,
unsigned int n_fields)
{
struct dynevent_arg arg;
unsigned int i;
int ret = 0;
cmd->event_name = name;
cmd->private_data = mod;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (n_fields > SYNTH_FIELDS_MAX)
return -EINVAL;
dynevent_arg_init(&arg, 0);
arg.str = name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
for (i = 0; i < n_fields; i++) {
if (fields[i].type == NULL || fields[i].name == NULL)
return -EINVAL;
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
if (ret)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
static int save_cmdstr(int argc, const char *name, const char **argv)
{
struct seq_buf s;
char *buf;
int i;
buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
if (!buf)
return -ENOMEM;
seq_buf_init(&s, buf, MAX_DYNEVENT_CMD_LEN);
seq_buf_puts(&s, name);
for (i = 0; i < argc; i++) {
seq_buf_putc(&s, ' ');
seq_buf_puts(&s, argv[i]);
}
if (!seq_buf_buffer_left(&s)) {
synth_err(SYNTH_ERR_CMD_TOO_LONG, 0);
kfree(buf);
return -EINVAL;
}
buf[s.len] = 0;
last_cmd_set(buf);
kfree(buf);
return 0;
}
static int __create_synth_event(int argc, const char *name, const char **argv)
{
struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
struct synth_event *event = NULL;
int i, consumed = 0, n_fields = 0, ret = 0;
ret = save_cmdstr(argc, name, argv);
if (ret)
return ret;
/*
* Argument syntax:
* - Add synthetic event: <event_name> field[;field] ...
* - Remove synthetic event: !<event_name> field[;field] ...
* where 'field' = type field_name
*/
if (name[0] == '\0' || argc < 1) {
synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
return -EINVAL;
}
mutex_lock(&event_mutex);
if (!is_good_name(name)) {
synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
ret = -EINVAL;
goto out;
}
event = find_synth_event(name);
if (event) {
synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
ret = -EEXIST;
goto out;
}
for (i = 0; i < argc - 1; i++) {
if (strcmp(argv[i], ";") == 0)
continue;
if (n_fields == SYNTH_FIELDS_MAX) {
synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
ret = -EINVAL;
goto err;
}
field = parse_synth_field(argc - i, &argv[i], &consumed);
if (IS_ERR(field)) {
ret = PTR_ERR(field);
goto err;
}
fields[n_fields++] = field;
i += consumed - 1;
}
if (i < argc && strcmp(argv[i], ";") != 0) {
synth_err(SYNTH_ERR_INVALID_FIELD, errpos(argv[i]));
ret = -EINVAL;
goto err;
}
event = alloc_synth_event(name, n_fields, fields);
if (IS_ERR(event)) {
ret = PTR_ERR(event);
event = NULL;
goto err;
}
ret = register_synth_event(event);
if (!ret)
dyn_event_add(&event->devent);
else
free_synth_event(event);
out:
mutex_unlock(&event_mutex);
return ret;
err:
for (i = 0; i < n_fields; i++)
free_synth_field(fields[i]);
goto out;
}
/**
* synth_event_create - Create a new synthetic event
* @name: The name of the new sythetic event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
* @mod: The module creating the event, NULL if not created from a module
*
* Create a new synthetic event with the given name under the
* trace/events/synthetic/ directory. The event fields that will be
* defined for the event should be passed in as an array of struct
* synth_field_desc, and the number elements in the array passed in as
* n_fields. Field ordering will retain the ordering given in the
* fields array.
*
* If the new synthetic event is being created from a module, the mod
* param must be non-NULL. This will ensure that the trace buffer
* won't contain unreadable events.
*
* The new synth event should be deleted using synth_event_delete()
* function. The new synthetic event can be generated from modules or
* other kernel code using trace_synth_event() and related functions.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_create(const char *name, struct synth_field_desc *fields,
unsigned int n_fields, struct module *mod)
{
struct dynevent_cmd cmd;
char *buf;
int ret;
buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
if (!buf)
return -ENOMEM;
synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
fields, n_fields);
if (ret)
goto out;
ret = synth_event_gen_cmd_end(&cmd);
out:
kfree(buf);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_create);
static int destroy_synth_event(struct synth_event *se)
{
int ret;
if (se->ref)
ret = -EBUSY;
else {
ret = unregister_synth_event(se);
if (!ret) {
dyn_event_remove(&se->devent);
free_synth_event(se);
}
}
return ret;
}
/**
* synth_event_delete - Delete a synthetic event
* @event_name: The name of the new sythetic event
*
* Delete a synthetic event that was created with synth_event_create().
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_delete(const char *event_name)
{
struct synth_event *se = NULL;
struct module *mod = NULL;
int ret = -ENOENT;
mutex_lock(&event_mutex);
se = find_synth_event(event_name);
if (se) {
mod = se->mod;
ret = destroy_synth_event(se);
}
mutex_unlock(&event_mutex);
if (mod) {
mutex_lock(&trace_types_lock);
/*
* It is safest to reset the ring buffer if the module
* being unloaded registered any events that were
* used. The only worry is if a new module gets
* loaded, and takes on the same id as the events of
* this module. When printing out the buffer, traced
* events left over from this module may be passed to
* the new module events and unexpected results may
* occur.
*/
tracing_reset_all_online_cpus();
mutex_unlock(&trace_types_lock);
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_delete);
static int create_or_delete_synth_event(int argc, char **argv)
{
const char *name = argv[0];
int ret;
/* trace_run_command() ensures argc != 0 */
if (name[0] == '!') {
ret = synth_event_delete(name + 1);
return ret;
}
ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
return ret == -ECANCELED ? -EINVAL : ret;
}
static int synth_event_run_command(struct dynevent_cmd *cmd)
{
struct synth_event *se;
int ret;
ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
if (ret)
return ret;
se = find_synth_event(cmd->event_name);
if (WARN_ON(!se))
return -ENOENT;
se->mod = cmd->private_data;
return ret;
}
/**
* synth_event_cmd_init - Initialize a synthetic event command object
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @buf: A pointer to the buffer used to build the command
* @maxlen: The length of the buffer passed in @buf
*
* Initialize a synthetic event command object. Use this before
* calling any of the other dyenvent_cmd functions.
*/
void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
{
dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
synth_event_run_command);
}
EXPORT_SYMBOL_GPL(synth_event_cmd_init);
static inline int
__synth_event_trace_init(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
int ret = 0;
memset(trace_state, '\0', sizeof(*trace_state));
/*
* Normal event tracing doesn't get called at all unless the
* ENABLED bit is set (which attaches the probe thus allowing
* this code to be called, etc). Because this is called
* directly by the user, we don't have that but we still need
* to honor not logging when disabled. For the iterated
* trace case, we save the enabed state upon start and just
* ignore the following data calls.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file)) {
trace_state->disabled = true;
ret = -ENOENT;
goto out;
}
trace_state->event = file->event_call->data;
out:
return ret;
}
static inline int
__synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state,
int dynamic_fields_size)
{
int entry_size, fields_size = 0;
int ret = 0;
fields_size = trace_state->event->n_u64 * sizeof(u64);
fields_size += dynamic_fields_size;
/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
trace_state->buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(trace_state->buffer);
entry_size = sizeof(*trace_state->entry) + fields_size;
trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
file,
entry_size);
if (!trace_state->entry) {
ring_buffer_nest_end(trace_state->buffer);
ret = -EINVAL;
}
return ret;
}
static inline void
__synth_event_trace_end(struct synth_event_trace_state *trace_state)
{
trace_event_buffer_commit(&trace_state->fbuffer);
ring_buffer_nest_end(trace_state->buffer);
}
/**
* synth_event_trace - Trace a synthetic event
* @file: The trace_event_file representing the synthetic event
* @n_vals: The number of values in vals
* @args: Variable number of args containing the event values
*
* Trace a synthetic event using the values passed in the variable
* argument list.
*
* The argument list should be a list 'n_vals' u64 values. The number
* of vals must match the number of field in the synthetic event, and
* must be in the same order as the synthetic event fields.
*
* All vals should be cast to u64, and string vals are just pointers
* to strings, cast to u64. Strings will be copied into space
* reserved in the event for the string, using these pointers.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
{
unsigned int i, n_u64, len, data_size = 0;
struct synth_event_trace_state state;
va_list args;
int ret;
ret = __synth_event_trace_init(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (state.event->n_dynamic_fields) {
va_start(args, n_vals);
for (i = 0; i < state.event->n_fields; i++) {
u64 val = va_arg(args, u64);
if (state.event->fields[i]->is_string &&
state.event->fields[i]->is_dynamic) {
char *str_val = (char *)(long)val;
data_size += strlen(str_val) + 1;
}
}
va_end(args);
}
ret = __synth_event_trace_start(file, &state, data_size);
if (ret)
return ret;
if (n_vals != state.event->n_fields) {
ret = -EINVAL;
goto out;
}
data_size = 0;
va_start(args, n_vals);
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
u64 val;
val = va_arg(args, u64);
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)val;
len = trace_string(state.entry, state.event, str_val,
state.event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = state.event->fields[i];
switch (field->size) {
case 1:
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
break;
default:
state.entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
va_end(args);
out:
__synth_event_trace_end(&state);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace);
/**
* synth_event_trace_array - Trace a synthetic event from an array
* @file: The trace_event_file representing the synthetic event
* @vals: Array of values
* @n_vals: The number of values in vals
*
* Trace a synthetic event using the values passed in as 'vals'.
*
* The 'vals' array is just an array of 'n_vals' u64. The number of
* vals must match the number of field in the synthetic event, and
* must be in the same order as the synthetic event fields.
*
* All vals should be cast to u64, and string vals are just pointers
* to strings, cast to u64. Strings will be copied into space
* reserved in the event for the string, using these pointers.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
unsigned int n_vals)
{
unsigned int i, n_u64, field_pos, len, data_size = 0;
struct synth_event_trace_state state;
char *str_val;
int ret;
ret = __synth_event_trace_init(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (state.event->n_dynamic_fields) {
for (i = 0; i < state.event->n_dynamic_fields; i++) {
field_pos = state.event->dynamic_fields[i]->field_pos;
str_val = (char *)(long)vals[field_pos];
len = strlen(str_val) + 1;
data_size += len;
}
}
ret = __synth_event_trace_start(file, &state, data_size);
if (ret)
return ret;
if (n_vals != state.event->n_fields) {
ret = -EINVAL;
goto out;
}
data_size = 0;
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)vals[i];
len = trace_string(state.entry, state.event, str_val,
state.event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = state.event->fields[i];
u64 val = vals[i];
switch (field->size) {
case 1:
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
break;
default:
state.entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
out:
__synth_event_trace_end(&state);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace_array);
/**
* synth_event_trace_start - Start piecewise synthetic event trace
* @file: The trace_event_file representing the synthetic event
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Start the trace of a synthetic event field-by-field rather than all
* at once.
*
* This function 'opens' an event trace, which means space is reserved
* for the event in the trace buffer, after which the event's
* individual field values can be set through either
* synth_event_add_next_val() or synth_event_add_val().
*
* A pointer to a trace_state object is passed in, which will keep
* track of the current event trace state until the event trace is
* closed (and the event finally traced) using
* synth_event_trace_end().
*
* Note that synth_event_trace_end() must be called after all values
* have been added for each event trace, regardless of whether adding
* all field values succeeded or not.
*
* Note also that for a given event trace, all fields must be added
* using either synth_event_add_next_val() or synth_event_add_val()
* but not both together or interleaved.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
int ret;
if (!trace_state)
return -EINVAL;
ret = __synth_event_trace_init(file, trace_state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (trace_state->event->n_dynamic_fields)
return -ENOTSUPP;
ret = __synth_event_trace_start(file, trace_state, 0);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace_start);
static int __synth_event_add_val(const char *field_name, u64 val,
struct synth_event_trace_state *trace_state)
{
struct synth_field *field = NULL;
struct synth_trace_event *entry;
struct synth_event *event;
int i, ret = 0;
if (!trace_state) {
ret = -EINVAL;
goto out;
}
/* can't mix add_next_synth_val() with add_synth_val() */
if (field_name) {
if (trace_state->add_next) {
ret = -EINVAL;
goto out;
}
trace_state->add_name = true;
} else {
if (trace_state->add_name) {
ret = -EINVAL;
goto out;
}
trace_state->add_next = true;
}
if (trace_state->disabled)
goto out;
event = trace_state->event;
if (trace_state->add_name) {
for (i = 0; i < event->n_fields; i++) {
field = event->fields[i];
if (strcmp(field->name, field_name) == 0)
break;
}
if (!field) {
ret = -EINVAL;
goto out;
}
} else {
if (trace_state->cur_field >= event->n_fields) {
ret = -EINVAL;
goto out;
}
field = event->fields[trace_state->cur_field++];
}
entry = trace_state->entry;
if (field->is_string) {
char *str_val = (char *)(long)val;
char *str_field;
if (field->is_dynamic) { /* add_val can't do dynamic strings */
ret = -EINVAL;
goto out;
}
if (!str_val) {
ret = -EINVAL;
goto out;
}
str_field = (char *)&entry->fields[field->offset];
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
} else {
switch (field->size) {
case 1:
*(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
break;
case 2:
*(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
break;
case 4:
*(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
break;
default:
trace_state->entry->fields[field->offset] = val;
break;
}
}
out:
return ret;
}
/**
* synth_event_add_next_val - Add the next field's value to an open synth trace
* @val: The value to set the next field to
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Set the value of the next field in an event that's been opened by
* synth_event_trace_start().
*
* The val param should be the value cast to u64. If the value points
* to a string, the val param should be a char * cast to u64.
*
* This function assumes all the fields in an event are to be set one
* after another - successive calls to this function are made, one for
* each field, in the order of the fields in the event, until all
* fields have been set. If you'd rather set each field individually
* without regard to ordering, synth_event_add_val() can be used
* instead.
*
* Note however that synth_event_add_next_val() and
* synth_event_add_val() can't be intermixed for a given event trace -
* one or the other but not both can be used at the same time.
*
* Note also that synth_event_trace_end() must be called after all
* values have been added for each event trace, regardless of whether
* adding all field values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_add_next_val(u64 val,
struct synth_event_trace_state *trace_state)
{
return __synth_event_add_val(NULL, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_next_val);
/**
* synth_event_add_val - Add a named field's value to an open synth trace
* @field_name: The name of the synthetic event field value to set
* @val: The value to set the next field to
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Set the value of the named field in an event that's been opened by
* synth_event_trace_start().
*
* The val param should be the value cast to u64. If the value points
* to a string, the val param should be a char * cast to u64.
*
* This function looks up the field name, and if found, sets the field
* to the specified value. This lookup makes this function more
* expensive than synth_event_add_next_val(), so use that or the
* none-piecewise synth_event_trace() instead if efficiency is more
* important.
*
* Note however that synth_event_add_next_val() and
* synth_event_add_val() can't be intermixed for a given event trace -
* one or the other but not both can be used at the same time.
*
* Note also that synth_event_trace_end() must be called after all
* values have been added for each event trace, regardless of whether
* adding all field values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_add_val(const char *field_name, u64 val,
struct synth_event_trace_state *trace_state)
{
return __synth_event_add_val(field_name, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_val);
/**
* synth_event_trace_end - End piecewise synthetic event trace
* @trace_state: A pointer to object tracking the piecewise trace state
*
* End the trace of a synthetic event opened by
* synth_event_trace__start().
*
* This function 'closes' an event trace, which basically means that
* it commits the reserved event and cleans up other loose ends.
*
* A pointer to a trace_state object is passed in, which will keep
* track of the current event trace state opened with
* synth_event_trace_start().
*
* Note that this function must be called after all values have been
* added for each event trace, regardless of whether adding all field
* values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_end(struct synth_event_trace_state *trace_state)
{
if (!trace_state)
return -EINVAL;
__synth_event_trace_end(trace_state);
return 0;
}
EXPORT_SYMBOL_GPL(synth_event_trace_end);
static int create_synth_event(int argc, const char **argv)
{
const char *name = argv[0];
int len;
if (name[0] != 's' || name[1] != ':')
return -ECANCELED;
name += 2;
/* This interface accepts group name prefix */
if (strchr(name, '/')) {
len = str_has_prefix(name, SYNTH_SYSTEM "/");
if (len == 0)
return -EINVAL;
name += len;
}
return __create_synth_event(argc - 1, name, argv + 1);
}
static int synth_event_release(struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
int ret;
if (event->ref)
return -EBUSY;
ret = unregister_synth_event(event);
if (ret)
return ret;
dyn_event_remove(ev);
free_synth_event(event);
return 0;
}
static int __synth_event_show(struct seq_file *m, struct synth_event *event)
{
struct synth_field *field;
unsigned int i;
char *type, *t;
seq_printf(m, "%s\t", event->name);
for (i = 0; i < event->n_fields; i++) {
field = event->fields[i];
type = field->type;
t = strstr(type, "__data_loc");
if (t) { /* __data_loc belongs in format but not event desc */
t += sizeof("__data_loc");
type = t;
}
/* parameter values */
seq_printf(m, "%s %s%s", type, field->name,
i == event->n_fields - 1 ? "" : "; ");
}
seq_putc(m, '\n');
return 0;
}
static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
seq_printf(m, "s:%s/", event->class.system);
return __synth_event_show(m, event);
}
static int synth_events_seq_show(struct seq_file *m, void *v)
{
struct dyn_event *ev = v;
if (!is_synth_event(ev))
return 0;
return __synth_event_show(m, to_synth_event(ev));
}
static const struct seq_operations synth_events_seq_op = {
.start = dyn_event_seq_start,
.next = dyn_event_seq_next,
.stop = dyn_event_seq_stop,
.show = synth_events_seq_show,
};
static int synth_events_open(struct inode *inode, struct file *file)
{
int ret;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
ret = dyn_events_release_all(&synth_event_ops);
if (ret < 0)
return ret;
}
return seq_open(file, &synth_events_seq_op);
}
static ssize_t synth_events_write(struct file *file,
const char __user *buffer,
size_t count, loff_t *ppos)
{
return trace_parse_run_command(file, buffer, count, ppos,
create_or_delete_synth_event);
}
static const struct file_operations synth_events_fops = {
.open = synth_events_open,
.write = synth_events_write,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/*
* Register dynevent at core_initcall. This allows kernel to setup kprobe
* events in postcore_initcall without tracefs.
*/
static __init int trace_events_synth_init_early(void)
{
int err = 0;
err = dyn_event_register(&synth_event_ops);
if (err)
pr_warn("Could not register synth_event_ops\n");
return err;
}
core_initcall(trace_events_synth_init_early);
static __init int trace_events_synth_init(void)
{
struct dentry *entry = NULL;
int err = 0;
err = tracing_init_dentry();
if (err)
goto err;
entry = tracefs_create_file("synthetic_events", 0644, NULL,
NULL, &synth_events_fops);
if (!entry) {
err = -ENODEV;
goto err;
}
return err;
err:
pr_warn("Could not create tracefs 'synthetic_events' entry\n");
return err;
}
fs_initcall(trace_events_synth_init);