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-rw-r--r--src/tracefs-kprobes.c198
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);
+}