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Merge pull request #323 from iovisor/strlen
Add uprobe strlen histogram example
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#!/usr/bin/python | ||
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# | ||
# strlen_hist.py Histogram of system-wide strlen return values | ||
# | ||
# A basic example of using uprobes along with a histogram to show | ||
# distributions. | ||
# | ||
# Runs until ctrl-c is pressed. | ||
# | ||
# Copyright (c) PLUMgrid, Inc. | ||
# Licensed under the Apache License, Version 2.0 (the "License") | ||
# | ||
# Example output: | ||
# $ sudo ./strlen_hist.py | ||
# 22:12:52 | ||
# strlen return: : count distribution | ||
# 0 -> 1 : 2106 |**************** | | ||
# 2 -> 3 : 1172 |********* | | ||
# 4 -> 7 : 3892 |****************************** | | ||
# 8 -> 15 : 5096 |****************************************| | ||
# 16 -> 31 : 2201 |***************** | | ||
# 32 -> 63 : 547 |**** | | ||
# 64 -> 127 : 106 | | | ||
# 128 -> 255 : 13 | | | ||
# 256 -> 511 : 27 | | | ||
# 512 -> 1023 : 6 | | | ||
# 1024 -> 2047 : 10 | | | ||
# ^C$ | ||
# | ||
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from __future__ import print_function | ||
import bcc | ||
import time | ||
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text = """ | ||
#include <uapi/linux/ptrace.h> | ||
BPF_HISTOGRAM(dist); | ||
int count(struct pt_regs *ctx) { | ||
dist.increment(bpf_log2l(ctx->ax)); | ||
return 0; | ||
} | ||
""" | ||
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b = bcc.BPF(text=text) | ||
sym="strlen" | ||
b.attach_uretprobe(name="c", sym=sym, fn_name="count") | ||
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dist = b["dist"] | ||
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try: | ||
while True: | ||
time.sleep(1) | ||
print("%-8s\n" % time.strftime("%H:%M:%S"), end="") | ||
dist.print_log2_hist(sym + " return:") | ||
dist.clear() | ||
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except KeyboardInterrupt: | ||
pass |