| // 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); |
| } |
| |
| /** |
| * tracefs_kprobe_destroy - Remove an individual kprobe or kretprobe |
| * @system: The system of the kprobe to remove (could be NULL) |
| * @event: The event of the kprobe or kretprobe to remove |
| * @addr: The address used to create the kprobe |
| * @format: The format used to create the kprobe |
| * @force: If true, try to disable the kprobe/kretprobe first |
| * |
| * This removes the kprobe or kretprobe that was created by |
| * tracefs_kprobe_raw() or tracefs_kretprobe_raw(). |
| * |
| * Returns 0 on success and -1 otherwise. |
| */ |
| int tracefs_kprobe_destroy(const char *system, const char *event, |
| const char *addr, const char *format, bool force) |
| { |
| struct tracefs_dynevent *kp; |
| int ret; |
| |
| kp = tracefs_kprobe_alloc(system, event, addr, format); |
| if (!kp) |
| return -1; |
| |
| ret = tracefs_dynevent_destroy(kp, force); |
| |
| tracefs_dynevent_free(kp); |
| |
| return ret; |
| } |