updated opensnoop to use bpf_perf_output
diff --git a/tools/opensnoop.py b/tools/opensnoop.py
index 5df3b41..e6fcb07 100755
--- a/tools/opensnoop.py
+++ b/tools/opensnoop.py
@@ -10,10 +10,12 @@
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 17-Sep-2015 Brendan Gregg Created this.
+# 29-Apr-2016 Allan McAleavy updated for BPF_PERF_OUTPUT
from __future__ import print_function
from bcc import BPF
import argparse
+import ctypes as ct
# arguments
examples = """examples:
@@ -38,32 +40,67 @@
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
+#include <uapi/linux/limits.h>
+#include <linux/sched.h>
+
+struct val_t {
+ u32 pid;
+ u64 ts;
+ char comm[TASK_COMM_LEN];
+ const char *fname;
+};
+
+struct data_t {
+ u32 pid;
+ u64 ts;
+ u64 delta;
+ int ret;
+ char comm[TASK_COMM_LEN];
+ char fname[NAME_MAX];
+};
BPF_HASH(args_filename, u32, const char *);
+BPF_HASH(infotmp, u32, struct val_t);
+BPF_PERF_OUTPUT(events);
-int kprobe__sys_open(struct pt_regs *ctx, const char __user *filename)
+int trace_entry(struct pt_regs *ctx, const char __user *filename)
{
+ struct val_t val = {};
u32 pid = bpf_get_current_pid_tgid();
FILTER
- args_filename.update(&pid, &filename);
+ if (bpf_get_current_comm(&val.comm, sizeof(val.comm)) == 0) {
+ val.pid = bpf_get_current_pid_tgid();
+ val.ts = bpf_ktime_get_ns();
+ val.fname = filename;
+ infotmp.update(&pid, &val);
+ }
return 0;
};
-int kretprobe__sys_open(struct pt_regs *ctx)
+int trace_return(struct pt_regs *ctx)
{
- const char **filenamep;
- int ret = ctx->ax;
u32 pid = bpf_get_current_pid_tgid();
+ struct val_t *valp;
+ struct data_t data = {};
- filenamep = args_filename.lookup(&pid);
- if (filenamep == 0) {
+ u64 tsp = bpf_ktime_get_ns();
+
+ valp = infotmp.lookup(&pid);
+ if (valp == 0) {
// missed entry
return 0;
}
+ bpf_probe_read(&data.comm, sizeof(data.comm), valp->comm);
+ bpf_probe_read(&data.fname, sizeof(data.fname), (void *)valp->fname);
+ data.pid = valp->pid;
+ data.delta = tsp - valp->ts;
+ data.ts = tsp / 1000;
+ data.ret = ctx->ax;
- bpf_trace_printk("%d %s\\n", ret, *filenamep);
+ events.perf_submit(ctx, &data, sizeof(data));
+ infotmp.delete(&pid);
args_filename.delete(&pid);
return 0;
@@ -79,34 +116,68 @@
# initialize BPF
b = BPF(text=bpf_text)
+b.attach_kprobe(event="sys_open", fn_name="trace_entry")
+b.attach_kretprobe(event="sys_open", fn_name="trace_return")
+
+TASK_COMM_LEN = 16 # linux/sched.h
+NAME_MAX = 255 # linux/limits.h
+
+class Data(ct.Structure):
+ _fields_ = [
+ ("pid", ct.c_ulonglong),
+ ("ts", ct.c_ulonglong),
+ ("delta", ct.c_ulonglong),
+ ("ret", ct.c_int),
+ ("comm", ct.c_char * TASK_COMM_LEN),
+ ("fname", ct.c_char * NAME_MAX)
+ ]
+
+start_ts = 0
+prev_ts = 0
+delta = 0
# header
if args.timestamp:
print("%-14s" % ("TIME(s)"), end="")
print("%-6s %-16s %4s %3s %s" % ("PID", "COMM", "FD", "ERR", "PATH"))
-start_ts = 0
-
-# format output
-while 1:
- (task, pid, cpu, flags, ts, msg) = b.trace_fields()
- (ret_s, filename) = msg.split(" ", 1)
-
- ret = int(ret_s)
- if (args.failed and (ret >= 0)):
- continue
+# process event
+def print_event(cpu, data, size):
+ event = ct.cast(data, ct.POINTER(Data)).contents
+ global start_ts
+ global prev_ts
+ global delta
+ global cont
# split return value into FD and errno columns
- if ret >= 0:
- fd_s = ret
+ if event.ret >= 0:
+ fd_s = event.ret
err = 0
else:
- fd_s = "-1"
- err = - ret
+ fd_s = -1
+ err = - event.ret
- # print columns
+ if start_ts == 0:
+ prev_ts = start_ts
+
+ if start_ts == 1:
+ delta = float(delta) + (event.ts - prev_ts)
+
+ if (args.failed and (event.ret >= 0)):
+ start_ts = 1
+ prev_ts = event.ts
+ return
+
if args.timestamp:
- if start_ts == 0:
- start_ts = ts
- print("%-14.9f" % (ts - start_ts), end="")
- print("%-6d %-16s %4s %3s %s" % (pid, task, fd_s, err, filename))
+ print("%-14.9f" % (delta / 1000000), end="")
+
+ print("%-6d %-16s %4d %3d %s" % (event.pid, event.comm,
+ fd_s, err, event.fname))
+
+ prev_ts = event.ts
+ start_ts = 1
+
+# loop with callback to print_event
+b["events"].open_perf_buffer(print_event)
+while 1:
+ b.kprobe_poll()
