linux-trace-devel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: linux-trace-devel@vger.kernel.org
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH v5 2/7] libtracefs: Implement tracefs_kprobe_raw()
Date: Fri,  2 Jul 2021 10:22:37 -0400	[thread overview]
Message-ID: <20210702142242.163989-3-rostedt@goodmis.org> (raw)
In-Reply-To: <20210702142242.163989-1-rostedt@goodmis.org>

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a function to facilitate creating a kprobe event. It has the "raw" in
its name because it still requires knowing the format of the kprobe. But
does handle the kprobe naming better and writing to the kprobe_event file.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/tracefs.h     |  4 +++
 src/Makefile          |  1 +
 src/tracefs-kprobes.c | 72 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 src/tracefs-kprobes.c

diff --git a/include/tracefs.h b/include/tracefs.h
index a21d2d2f22a6..bc504bcb0188 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -214,4 +214,8 @@ int tracefs_tracer_clear(struct tracefs_instance *instance);
 ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int flags);
 ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
 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);
+
 #endif /* _TRACE_FS_H */
diff --git a/src/Makefile b/src/Makefile
index b4cff07efc50..0697a047f4bc 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -8,6 +8,7 @@ OBJS += tracefs-instance.o
 OBJS += tracefs-events.o
 OBJS += tracefs-tools.o
 OBJS += tracefs-marker.o
+OBJS += tracefs-kprobes.o
 
 OBJS := $(OBJS:%.o=$(bdir)/%.o)
 DEPS := $(OBJS:$(bdir)/%.o=$(bdir)/.%.d)
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
new file mode 100644
index 000000000000..d50191d55181
--- /dev/null
+++ b/src/tracefs-kprobes.c
@@ -0,0 +1,72 @@
+// 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"
+
+/**
+ * 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)
+{
+	char *str;
+	int ret;
+
+	if (!tracefs_file_exists(NULL, KPROBE_EVENTS))
+		return -1;
+
+	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 ret < 0 ? ret : 0;
+}
-- 
2.30.2


  parent reply	other threads:[~2021-07-02 14:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02 14:22 [PATCH v5 0/7] libtracefs: Facilitate adding and removing kprobes Steven Rostedt
2021-07-02 14:22 ` [PATCH v5 1/7] libtracefs: Implement tracefs_instances() Steven Rostedt
2021-07-02 14:22 ` Steven Rostedt [this message]
2021-07-02 14:22 ` [PATCH v5 3/7] libtracefs: Implement tracefs_kretprobe_raw() Steven Rostedt
2021-07-02 14:22 ` [PATCH v5 4/7] libtracefs: Implement tracefs_get_kprobes() Steven Rostedt
2021-07-02 14:22 ` [PATCH v5 5/7] libtracefs: Implement tracefs_kprobe_clear_all() to remove all kprobes Steven Rostedt
2021-07-02 14:22 ` [PATCH v5 6/7] libtracefs: Implement tracefs_kprobe_clear_probe() Steven Rostedt
2021-07-02 14:22 ` [PATCH v5 7/7] libtracefs: Add man pages for kprobe functions Steven Rostedt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210702142242.163989-3-rostedt@goodmis.org \
    --to=rostedt@goodmis.org \
    --cc=linux-trace-devel@vger.kernel.org \
    --subject='Re: [PATCH v5 2/7] libtracefs: Implement tracefs_kprobe_raw()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).