lkml.org 
[lkml]   [2019]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RFC 3/4] lib/bpf: Add support for ftrace event attach and detach
Date
Add the needed library support in this commit.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
tools/lib/bpf/bpf.c | 53 ++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/bpf.h | 4 +++
tools/lib/bpf/libbpf.map | 2 ++
3 files changed, 59 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index c4a48086dc9a..28c5a7d00d14 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -24,6 +24,9 @@
#include <stdlib.h>
#include <string.h>
#include <memory.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <linux/bpf.h>
@@ -57,6 +60,8 @@
#define min(x, y) ((x) < (y) ? (x) : (y))
#endif

+#define TRACEFS "/sys/kernel/debug/tracing"
+
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
@@ -658,6 +663,54 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd)
return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
}

+int bpf_raw_tracepoint_ftrace_attach(const char *subsys, const char *name,
+ int prog_fd)
+{
+ char buf[256];
+ int len, ret, tfd;
+
+ sprintf(buf, "%s/events/%s/%s/bpf", TRACEFS, subsys, name);
+ tfd = open(buf, O_WRONLY);
+ if (tfd < 0)
+ return tfd;
+
+ sprintf(buf, "attach:%d", prog_fd);
+ len = strlen(buf);
+ ret = write(tfd, buf, len);
+
+ if (ret < 0)
+ goto err;
+ if (ret != len)
+ ret = -1;
+err:
+ close(tfd);
+ return ret;
+}
+
+int bpf_raw_tracepoint_ftrace_detach(const char *subsys, const char *name,
+ int prog_fd)
+{
+ char buf[256];
+ int len, ret, tfd;
+
+ sprintf(buf, "%s/events/%s/%s/bpf", TRACEFS, subsys, name);
+ tfd = open(buf, O_WRONLY);
+ if (tfd < 0)
+ return tfd;
+
+ sprintf(buf, "detach:%d", prog_fd);
+ len = strlen(buf);
+ ret = write(tfd, buf, len);
+
+ if (ret < 0)
+ goto err;
+ if (ret != len)
+ ret = -1;
+err:
+ close(tfd);
+ return ret;
+}
+
int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
bool do_log)
{
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 9593fec75652..5b9c44658037 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -163,6 +163,10 @@ LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,
__u32 query_flags, __u32 *attach_flags,
__u32 *prog_ids, __u32 *prog_cnt);
LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd);
+LIBBPF_API int bpf_raw_tracepoint_ftrace_attach(const char *subsys,
+ const char *name, int prog_fd);
+LIBBPF_API int bpf_raw_tracepoint_ftrace_detach(const char *subsys,
+ const char *name, int prog_fd);
LIBBPF_API int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf,
__u32 log_buf_size, bool do_log);
LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 673001787cba..fca377b688c2 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -163,4 +163,6 @@ LIBBPF_0.0.3 {
bpf_map__is_internal;
bpf_map_freeze;
btf__finalize_data;
+ bpf_raw_tracepoint_ftrace_attach;
+ bpf_raw_tracepoint_ftrace_detach;
} LIBBPF_0.0.2;
--
2.22.0.410.gd8fdbe21b5-goog
\
 
 \ /
  Last update: 2019-07-10 16:17    [W:0.180 / U:0.320 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site