Danny's tech notebook | 丹尼技術手札: Userspace

#!/usr/bin/python

from __future__ import print_function
from bcc import BPF
from time import sleep

# load BPF program

b = BPF(text="""
#include <uapi/linux/ptrace.h>
struct key_t {
char c[80];
};
BPF_HASH(counts, struct key_t);

int count(struct pt_regs *ctx) {
if (!PT_REGS_PARM1(ctx))
return 0;

struct key_t key = {};
u64 zero = 0, *val;
bpf_probe_read(&key.c, sizeof(key.c), (void *)PT_REGS_PARM1(ctx));
val = counts.lookup_or_init(&key, &zero);
(*val)++;
return 0;
};
""")

b.attach_uprobe(name="c", sym="strlen", fn_name="count")

# header
print("Tracing strlen()... Hit Ctrl-C to end.")

# sleep until Ctrl-C
try:
sleep(99999999)
except KeyboardInterrupt:
pass

# print output
print("%10s %s" % ("COUNT", "STRING"))
counts = b.get_table("counts")
for k, v in sorted(counts.items(), key=lambda counts: counts[1].value):
print("%10d \"%s\"" % (v.value, k.c.encode('string-escape')))

Reference:
https://github.com/iovisor/bcc/blob/master/tools/bashreadline.py
https://github.com/iovisor/bcc/blob/master/tools/gethostlatency.py
https://github.com/iovisor/bcc/blob/master/tools/funccount.py
https://github.com/iovisor/bcc/blob/master/tools/memleak.py
https://github.com/iovisor/bcc/blob/master/tools/dbslower.py
https://github.com/iovisor/bcc/blob/master/tools/trace.py

//Search "attach_uprobe path:tools language:python" in github project: iovisor/bcc