From: Sameeruddin shaik <sameeruddin.shaik8@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org,
Sameeruddin shaik <sameeruddin.shaik8@gmail.com>
Subject: [PATCH] libtracefs: New API to trace only specific functions by instance
Date: Mon, 22 Feb 2021 17:54:21 +0530 [thread overview]
Message-ID: <1613996661-6525-1-git-send-email-sameeruddin.shaik8@gmail.com> (raw)
In-Reply-To: <[PATCH][WIP]libtracefs:New API to enable the filtering of functions>
This new API can be used to set the specific functions to be traced.
tracefs_function_filter
Signed-off-by: Sameeruddin shaik <sameeruddin.shaik8@gmail.com>
diff --git a/include/tracefs-local.h b/include/tracefs-local.h
index 187870e..e8ad1f9 100644
--- a/include/tracefs-local.h
+++ b/include/tracefs-local.h
@@ -20,6 +20,7 @@ void warning(const char *fmt, ...);
int str_read_file(const char *file, char **buffer);
char *trace_append_file(const char *dir, const char *name);
char *trace_find_tracing_dir(void);
+int controlled_write(const char *path, const char* const *filter, bool reset);
#ifndef ACCESSPERMS
#define ACCESSPERMS (S_IRWXU|S_IRWXG|S_IRWXO) /* 0777 */
diff --git a/include/tracefs.h b/include/tracefs.h
index f3eec62..37eab87 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -50,6 +50,7 @@ int tracefs_trace_on(struct tracefs_instance *instance);
int tracefs_trace_off(struct tracefs_instance *instance);
int tracefs_trace_on_fd(int fd);
int tracefs_trace_off_fd(int fd);
+int tracefs_function_filter(struct tracefs_instance *instance, const char* const *filter, bool reset);
/**
* tracefs_trace_on_get_fd - Get a file descriptor of "tracing_on" in given instance
diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c
index e2dfc7b..709f1e7 100644
--- a/src/tracefs-tools.c
+++ b/src/tracefs-tools.c
@@ -18,6 +18,7 @@
#include "tracefs-local.h"
#define TRACE_CTRL "tracing_on"
+#define TRACE_FILTER "set_ftrace_filter"
static const char * const options_map[] = {
"unknown",
@@ -387,3 +388,28 @@ void tracefs_option_clear(struct tracefs_options_mask *options, enum tracefs_opt
if (options && id > TRACEFS_OPTION_INVALID)
options->mask &= ~(1ULL << (id - 1));
}
+
+/**
+ * tracefs_function_filter - write to set_ftrace_filter file to trace particular functions
+ * @instance: ftrace instance, can be NULL for top tracing instnace
+ * @filter: const pointer to an array of const function names
+ * @reset: Boolean value to reset the file
+ */
+int tracefs_function_filter(struct tracefs_instance *instance, const char * const *filters, bool reset)
+{
+ char *ftrace_filter_path;
+ int ret;
+
+ if (!filters)
+ return -1;
+ ftrace_filter_path = tracefs_instance_get_file(instance, TRACE_FILTER);
+
+ if (!ftrace_filter_path)
+ goto gracefully_free;
+
+ ret = controlled_write(ftrace_filter_path, filters, reset);
+
+ gracefully_free:
+ tracefs_put_tracing_file(ftrace_filter_path);
+ return ret;
+}
diff --git a/src/tracefs-utils.c b/src/tracefs-utils.c
index 0e96f8e..1cd98a2 100644
--- a/src/tracefs-utils.c
+++ b/src/tracefs-utils.c
@@ -228,3 +228,23 @@ __hidden int str_read_file(const char *file, char **buffer)
return size;
}
+
+__hidden int controlled_write(const char *filter_path, const char * const *filters, bool reset)
+{
+ int size = 0;
+ int fd;
+ int i;
+
+ if (!filters)
+ return -1;
+ if (reset)
+ fd = open(filter_path, O_WRONLY | O_APPEND | O_TRUNC);
+ else
+ fd = open(filter_path, O_WRONLY | O_APPEND);
+ if (fd < 0)
+ return -1;
+ for (i = 0; filters[i] != NULL ; i++)
+ size += write(fd, *(filters + i), strlen(*(filters + i)));
+ close(fd);
+ return size;
+}
--
2.7.4
next parent reply other threads:[~2021-02-21 12:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <[PATCH][WIP]libtracefs:New API to enable the filtering of functions>
2021-02-22 12:24 ` Sameeruddin shaik [this message]
2021-02-22 12:40 ` [PATCH] libtracefs: New API to trace only specific functions by instance Sameeruddin Shaik
2021-02-21 15:28 ` Steven Rostedt
2021-02-22 14:52 ` Steven Rostedt
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