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// SPDX-License-Identifier: LGPL-2.1
/*
* Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
*
* Updates:
* Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include "tracefs.h"
#include "tracefs-local.h"
#define KPROBE_EVENTS "kprobe_events"
#define KPROBE_DEFAULT_GROUP "kprobes"
static struct tracefs_dynevent *
kprobe_alloc(enum tracefs_dynevent_type type, const char *system, const char *event,
const char *addr, const char *format)
{
struct tracefs_dynevent *kp;
const char *sys = system;
const char *ename = event;
char *tmp;
if (!addr) {
errno = EBADMSG;
return NULL;
}
if (!sys)
sys = KPROBE_DEFAULT_GROUP;
if (!event) {
ename = strdup(addr);
if (!ename)
return NULL;
tmp = strchr(ename, ':');
if (tmp)
*tmp = '\0';
}
kp = dynevent_alloc(type, sys, ename, addr, format);
if (!event)
free((char *)ename);
return kp;
}
/**
* tracefs_kprobe_alloc - Allocate new kprobe
* @system: The system name (NULL for the default kprobes)
* @event: The event to create (NULL to use @addr for the event)
* @addr: The function and offset (or address) to insert the probe
* @format: The format string to define the probe.
*
* Allocate a kprobe context that will be in the @system group (or kprobes if
* @system is NULL). Have the name of @event (or @addr if @event is NULL). Will
* be inserted to @addr (function name, with or without offset, or a address).
* And the @format will define the format of the kprobe.
*
* See the Linux documentation file under:
* Documentation/trace/kprobetrace.rst
*
* The kprobe is not created in the system.
*
* Return a pointer to a kprobe context on success, or NULL on error.
* The returned pointer must be freed with tracefs_dynevent_free()
*
* errno will be set to EBADMSG if addr is NULL.
*/
struct tracefs_dynevent *
tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format)
{
return kprobe_alloc(TRACEFS_DYNEVENT_KPROBE, system, event, addr, format);
}
/**
* tracefs_kretprobe_alloc - Allocate new kretprobe
* @system: The system name (NULL for the default kprobes)
* @event: The event to create (NULL to use @addr for the event)
* @addr: The function and offset (or address) to insert the retprobe
* @format: The format string to define the retprobe.
* @max: Maximum number of instances of the specified function that
* can be probed simultaneously, or 0 for the default value.
*
* Allocate a kretprobe that will be in the @system group (or kprobes if
* @system is NULL). Have the name of @event (or @addr if @event is
* NULL). Will be inserted to @addr (function name, with or without
* offset, or a address). And the @format will define the raw format
* of the kprobe. See the Linux documentation file under:
* Documentation/trace/kprobetrace.rst
* The kretprobe is not created in the system.
*
* Return a pointer to a kprobe context on success, or NULL on error.
* The returned pointer must be freed with tracefs_dynevent_free()
*
* errno will be set to EBADMSG if addr is NULL.
*/
struct tracefs_dynevent *
tracefs_kretprobe_alloc(const char *system, const char *event,
const char *addr, const char *format, unsigned int max)
{
struct tracefs_dynevent *kp;
int ret;
kp = kprobe_alloc(TRACEFS_DYNEVENT_KRETPROBE, system, event, addr, format);
if (!kp)
return NULL;
if (!max)
return kp;
free(kp->prefix);
kp->prefix = NULL;
ret = asprintf(&kp->prefix, "r%d:", max);
if (ret < 0)
goto error;
return kp;
error:
tracefs_dynevent_free(kp);
return NULL;
}
static int kprobe_raw(enum tracefs_dynevent_type type, const char *system,
const char *event, const char *addr, const char *format)
{
static struct tracefs_dynevent *kp;
int ret;
kp = kprobe_alloc(type, system, event, addr, format);
if (!kp)
return -1;
ret = tracefs_dynevent_create(kp);
tracefs_dynevent_free(kp);
return ret;
}
/**
* tracefs_kprobe_raw - Create a kprobe using raw format
* @system: The system name (NULL for the default kprobes)
* @event: The event to create (NULL to use @addr for the event)
* @addr: The function and offset (or address) to insert the probe
* @format: The raw format string to define the probe.
*
* Create a kprobe that will be in the @system group (or kprobes if
* @system is NULL). Have the name of @event (or @addr if @event is
* NULL). Will be inserted to @addr (function name, with or without
* offset, or a address). And the @format will define the raw format
* of the kprobe. See the Linux documentation file under:
* Documentation/trace/kprobetrace.rst
*
* Return 0 on success, or -1 on error.
* If the syntex of @format was incorrect, running
* tracefs_error_last(NULL) may show what went wrong.
*
* errno will be set to EBADMSG if addr or format is NULL.
*/
int tracefs_kprobe_raw(const char *system, const char *event,
const char *addr, const char *format)
{
return kprobe_raw(TRACEFS_DYNEVENT_KPROBE, system, event, addr, format);
}
/**
* tracefs_kretprobe_raw - Create a kretprobe using raw format
* @system: The system name (NULL for the default kprobes)
* @event: The event to create (NULL to use @addr for the event)
* @addr: The function and offset (or address) to insert the retprobe
* @format: The raw format string to define the retprobe.
*
* Create a kretprobe that will be in the @system group (or kprobes if
* @system is NULL). Have the name of @event (or @addr if @event is
* NULL). Will be inserted to @addr (function name, with or without
* offset, or a address). And the @format will define the raw format
* of the kprobe. See the Linux documentation file under:
* Documentation/trace/kprobetrace.rst
*
* Return 0 on success, or -1 on error.
* If the syntex of @format was incorrect, running
* tracefs_error_last(NULL) may show what went wrong.
*
* errno will be set to EBADMSG if addr or format is NULL.
*/
int tracefs_kretprobe_raw(const char *system, const char *event,
const char *addr, const char *format)
{
return kprobe_raw(TRACEFS_DYNEVENT_KRETPROBE, system, event, addr, format);
}
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