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Diffstat (limited to 'src/tracefs-kprobes.c')
| -rw-r--r-- | src/tracefs-kprobes.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c new file mode 100644 index 0000000..a8c0163 --- /dev/null +++ b/src/tracefs-kprobes.c @@ -0,0 +1,198 @@ +// 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); +} |