From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Add an interface that is similar to tracefs_kprobe_raw() but creates a
"kretprobe". The difference between a kprobe and a kretprobe is that a
kretprobe comes at the end of a function.
See Documentation/trace/kprobetrace.rst in the Linux kernel source code
for more information. Note, kprobes are started with "p" and kretprobe
lines start with an "r".
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 2 ++
src/tracefs-kprobes.c | 79 ++++++++++++++++++++++++++++++-------------
2 files changed, 58 insertions(+), 23 deletions(-)
diff --git a/include/tracefs.h b/include/tracefs.h
index d7980c7..f9ce077 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -217,6 +217,8 @@ void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
int tracefs_kprobe_raw(const char *system, const char *event,
const char *addr, const char *format);
+int tracefs_kretprobe_raw(const char *system, const char *event,
+ const char *addr, const char *format);
int tracefs_kprobe_clear(bool force);
int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force);
#endif /* _TRACE_FS_H */
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 6f3fbac..e1282d5 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -20,6 +20,36 @@
#define KPROBE_EVENTS "kprobe_events"
+static int insert_kprobe(const char *type, const char *system,
+ const char *event, const char *addr,
+ const char *format)
+{
+ char *str;
+ int ret;
+
+ errno = EBADMSG;
+ if (!addr || !format)
+ return -1;
+
+ if (!event)
+ event = addr;
+
+ if (system)
+ ret = asprintf(&str, "%s:%s/%s %s %s\n",
+ type, system, event, addr, format);
+ else
+ ret = asprintf(&str, "%s:%s %s %s\n",
+ type, event, addr, format);
+
+ if (ret < 0)
+ return -1;
+
+ ret = tracefs_instance_file_append(NULL, KPROBE_EVENTS, str);
+ free(str);
+
+ return ret < 0 ? ret : 0;
+}
+
/**
* tracefs_kprobe_raw - Create a kprobe using raw format
* @system: The system name (NULL for the default kprobes)
@@ -43,30 +73,33 @@
int tracefs_kprobe_raw(const char *system, const char *event,
const char *addr, const char *format)
{
- char *str;
- int ret;
-
- errno = EBADMSG;
- if (!addr || !format)
- return -1;
-
- if (!event)
- event = addr;
-
- if (system)
- ret = asprintf(&str, "p:%s/%s %s %s\n",
- system, event, addr, format);
- else
- ret = asprintf(&str, "p:%s %s %s\n",
- event, addr, format);
-
- if (ret < 0)
- return -1;
-
- ret = tracefs_instance_file_append(NULL, KPROBE_EVENTS, str);
- free(str);
+ return insert_kprobe("p", system, event, addr, format);
+}
- return ret < 0 ? ret : 0;
+/**
+ * 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 insert_kprobe("r", system, event, addr, format);
}
struct instance_list {
--
2.31.1
|