#!/usr/bin/python
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# @lint-avoid-python-3-compatibility-imports
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#
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# opensnoop Trace open() syscalls.
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# For Linux, uses BCC, eBPF. Embedded C.
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#
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# USAGE: opensnoop [-h] [-T] [-x] [-p PID] [-d DURATION] [-t TID] [-n NAME]
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#
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# Copyright (c) 2015 Brendan Gregg.
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# Licensed under the Apache License, Version 2.0 (the "License")
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#
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# 17-Sep-2015 Brendan Gregg Created this.
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# 29-Apr-2016 Allan McAleavy Updated for BPF_PERF_OUTPUT.
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# 08-Oct-2016 Dina Goldshtein Support filtering by PID and TID.
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from __future__ import print_function
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from bcc import ArgString, BPF
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import argparse
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import ctypes as ct
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from datetime import datetime, timedelta
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# arguments
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examples = """examples:
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./opensnoop # trace all open() syscalls
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./opensnoop -T # include timestamps
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./opensnoop -x # only show failed opens
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./opensnoop -p 181 # only trace PID 181
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./opensnoop -t 123 # only trace TID 123
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./opensnoop -d 10 # trace for 10 seconds only
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./opensnoop -n main # only print process names containing "main"
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"""
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parser = argparse.ArgumentParser(
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description="Trace open() syscalls",
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formatter_class=argparse.RawDescriptionHelpFormatter,
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epilog=examples)
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parser.add_argument("-T", "--timestamp", action="store_true",
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help="include timestamp on output")
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parser.add_argument("-x", "--failed", action="store_true",
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help="only show failed opens")
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parser.add_argument("-p", "--pid",
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help="trace this PID only")
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parser.add_argument("-t", "--tid",
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help="trace this TID only")
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parser.add_argument("-d", "--duration",
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help="total duration of trace in seconds")
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parser.add_argument("-n", "--name",
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type=ArgString,
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help="only print process names containing this name")
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parser.add_argument("--ebpf", action="store_true",
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help=argparse.SUPPRESS)
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args = parser.parse_args()
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debug = 0
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if args.duration:
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args.duration = timedelta(seconds=int(args.duration))
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# define BPF program
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bpf_text = """
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#include <uapi/linux/ptrace.h>
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#include <uapi/linux/limits.h>
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#include <linux/sched.h>
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struct val_t {
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u64 id;
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char comm[TASK_COMM_LEN];
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const char *fname;
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};
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struct data_t {
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u64 id;
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u64 ts;
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int ret;
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char comm[TASK_COMM_LEN];
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char fname[NAME_MAX];
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};
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BPF_HASH(infotmp, u64, struct val_t);
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BPF_PERF_OUTPUT(events);
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int trace_entry(struct pt_regs *ctx, int dfd, const char __user *filename)
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{
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struct val_t val = {};
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u64 id = bpf_get_current_pid_tgid();
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u32 pid = id >> 32; // PID is higher part
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u32 tid = id; // Cast and get the lower part
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FILTER
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if (bpf_get_current_comm(&val.comm, sizeof(val.comm)) == 0) {
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val.id = id;
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val.fname = filename;
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infotmp.update(&id, &val);
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}
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return 0;
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};
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int trace_return(struct pt_regs *ctx)
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{
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u64 id = bpf_get_current_pid_tgid();
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struct val_t *valp;
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struct data_t data = {};
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u64 tsp = bpf_ktime_get_ns();
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valp = infotmp.lookup(&id);
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if (valp == 0) {
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// missed entry
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return 0;
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}
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bpf_probe_read(&data.comm, sizeof(data.comm), valp->comm);
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bpf_probe_read(&data.fname, sizeof(data.fname), (void *)valp->fname);
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data.id = valp->id;
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data.ts = tsp / 1000;
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data.ret = PT_REGS_RC(ctx);
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events.perf_submit(ctx, &data, sizeof(data));
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infotmp.delete(&id);
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return 0;
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}
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"""
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if args.tid: # TID trumps PID
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bpf_text = bpf_text.replace('FILTER',
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'if (tid != %s) { return 0; }' % args.tid)
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elif args.pid:
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bpf_text = bpf_text.replace('FILTER',
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'if (pid != %s) { return 0; }' % args.pid)
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else:
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bpf_text = bpf_text.replace('FILTER', '')
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if debug or args.ebpf:
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print(bpf_text)
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if args.ebpf:
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exit()
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# initialize BPF
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b = BPF(text=bpf_text)
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b.attach_kprobe(event="do_sys_open", fn_name="trace_entry")
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b.attach_kretprobe(event="do_sys_open", fn_name="trace_return")
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TASK_COMM_LEN = 16 # linux/sched.h
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NAME_MAX = 255 # linux/limits.h
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class Data(ct.Structure):
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_fields_ = [
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("id", ct.c_ulonglong),
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("ts", ct.c_ulonglong),
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("ret", ct.c_int),
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("comm", ct.c_char * TASK_COMM_LEN),
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("fname", ct.c_char * NAME_MAX)
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]
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initial_ts = 0
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# header
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if args.timestamp:
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print("%-14s" % ("TIME(s)"), end="")
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print("%-6s %-16s %4s %3s %s" %
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("TID" if args.tid else "PID", "COMM", "FD", "ERR", "PATH"))
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# process event
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def print_event(cpu, data, size):
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event = ct.cast(data, ct.POINTER(Data)).contents
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global initial_ts
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# split return value into FD and errno columns
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if event.ret >= 0:
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fd_s = event.ret
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err = 0
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else:
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fd_s = -1
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err = - event.ret
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if not initial_ts:
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initial_ts = event.ts
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if args.failed and (event.ret >= 0):
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return
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if args.name and bytes(args.name) not in event.comm:
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return
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if args.timestamp:
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delta = event.ts - initial_ts
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print("%-14.9f" % (float(delta) / 1000000), end="")
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print("%-6d %-16s %4d %3d %s" %
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(event.id & 0xffffffff if args.tid else event.id >> 32,
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event.comm.decode('utf-8', 'replace'), fd_s, err,
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event.fname.decode('utf-8', 'replace')))
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# loop with callback to print_event
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b["events"].open_perf_buffer(print_event, page_cnt=64)
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start_time = datetime.now()
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while not args.duration or datetime.now() - start_time < args.duration:
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b.perf_buffer_poll()
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