Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 1 | #!/usr/bin/python |
| 2 | # @lint-avoid-python-3-compatibility-imports |
| 3 | # |
| 4 | # statsnoop Trace stat() syscalls. |
| 5 | # For Linux, uses BCC, eBPF. Embedded C. |
| 6 | # |
| 7 | # USAGE: statsnoop [-h] [-t] [-x] [-p PID] |
| 8 | # |
| 9 | # Copyright 2016 Netflix, Inc. |
| 10 | # Licensed under the Apache License, Version 2.0 (the "License") |
| 11 | # |
| 12 | # 08-Feb-2016 Brendan Gregg Created this. |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 13 | # 17-Feb-2016 Allan McAleavy updated for BPF_PERF_OUTPUT |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 14 | |
| 15 | from __future__ import print_function |
| 16 | from bcc import BPF |
| 17 | import argparse |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 18 | import ctypes as ct |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 19 | |
| 20 | # arguments |
| 21 | examples = """examples: |
| 22 | ./statsnoop # trace all stat() syscalls |
| 23 | ./statsnoop -t # include timestamps |
| 24 | ./statsnoop -x # only show failed stats |
| 25 | ./statsnoop -p 181 # only trace PID 181 |
| 26 | """ |
| 27 | parser = argparse.ArgumentParser( |
| 28 | description="Trace stat() syscalls", |
| 29 | formatter_class=argparse.RawDescriptionHelpFormatter, |
| 30 | epilog=examples) |
| 31 | parser.add_argument("-t", "--timestamp", action="store_true", |
| 32 | help="include timestamp on output") |
| 33 | parser.add_argument("-x", "--failed", action="store_true", |
| 34 | help="only show failed stats") |
| 35 | parser.add_argument("-p", "--pid", |
| 36 | help="trace this PID only") |
Nathan Scott | cf0792f | 2018-02-02 16:56:50 +1100 | [diff] [blame] | 37 | parser.add_argument("--ebpf", action="store_true", |
| 38 | help=argparse.SUPPRESS) |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 39 | args = parser.parse_args() |
| 40 | debug = 0 |
| 41 | |
| 42 | # define BPF program |
| 43 | bpf_text = """ |
| 44 | #include <uapi/linux/ptrace.h> |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 45 | #include <uapi/linux/limits.h> |
| 46 | #include <linux/sched.h> |
| 47 | |
| 48 | struct val_t { |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 49 | const char *fname; |
| 50 | }; |
| 51 | |
| 52 | struct data_t { |
| 53 | u32 pid; |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 54 | u64 ts_ns; |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 55 | int ret; |
| 56 | char comm[TASK_COMM_LEN]; |
| 57 | char fname[NAME_MAX]; |
| 58 | }; |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 59 | |
| 60 | BPF_HASH(args_filename, u32, const char *); |
mcaleavya | 1a7bebf | 2016-02-18 22:30:33 +0000 | [diff] [blame] | 61 | BPF_HASH(infotmp, u32, struct val_t); |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 62 | BPF_PERF_OUTPUT(events); |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 63 | |
| 64 | int trace_entry(struct pt_regs *ctx, const char __user *filename) |
| 65 | { |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 66 | struct val_t val = {}; |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 67 | u32 pid = bpf_get_current_pid_tgid(); |
| 68 | |
| 69 | FILTER |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 70 | val.fname = filename; |
| 71 | infotmp.update(&pid, &val); |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 72 | |
| 73 | return 0; |
| 74 | }; |
| 75 | |
| 76 | int trace_return(struct pt_regs *ctx) |
| 77 | { |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 78 | u32 pid = bpf_get_current_pid_tgid(); |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 79 | struct val_t *valp; |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 80 | |
| 81 | valp = infotmp.lookup(&pid); |
| 82 | if (valp == 0) { |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 83 | // missed entry |
| 84 | return 0; |
| 85 | } |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 86 | |
| 87 | struct data_t data = {.pid = pid}; |
mcaleavya | 1a7bebf | 2016-02-18 22:30:33 +0000 | [diff] [blame] | 88 | bpf_probe_read(&data.fname, sizeof(data.fname), (void *)valp->fname); |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 89 | bpf_get_current_comm(&data.comm, sizeof(data.comm)); |
| 90 | data.ts_ns = bpf_ktime_get_ns(); |
Naveen N. Rao | 4afa96a | 2016-05-03 14:54:21 +0530 | [diff] [blame] | 91 | data.ret = PT_REGS_RC(ctx); |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 92 | |
mcaleavya | 1a7bebf | 2016-02-18 22:30:33 +0000 | [diff] [blame] | 93 | events.perf_submit(ctx, &data, sizeof(data)); |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 94 | infotmp.delete(&pid); |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 95 | args_filename.delete(&pid); |
| 96 | |
| 97 | return 0; |
| 98 | } |
| 99 | """ |
| 100 | if args.pid: |
| 101 | bpf_text = bpf_text.replace('FILTER', |
| 102 | 'if (pid != %s) { return 0; }' % args.pid) |
| 103 | else: |
| 104 | bpf_text = bpf_text.replace('FILTER', '') |
Nathan Scott | cf0792f | 2018-02-02 16:56:50 +1100 | [diff] [blame] | 105 | if debug or args.ebpf: |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 106 | print(bpf_text) |
Nathan Scott | cf0792f | 2018-02-02 16:56:50 +1100 | [diff] [blame] | 107 | if args.ebpf: |
| 108 | exit() |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 109 | |
| 110 | # initialize BPF |
| 111 | b = BPF(text=bpf_text) |
Sandipan Das | 16523a3 | 2017-10-05 12:13:12 +0530 | [diff] [blame] | 112 | |
| 113 | # for POSIX compliance, all architectures implement these |
| 114 | # system calls but the name of the actual entry point may |
| 115 | # be different for which we must check if the entry points |
| 116 | # actually exist before attaching the probes |
Yonghong Song | 6433569 | 2018-04-25 00:40:13 -0700 | [diff] [blame] | 117 | syscall_fnname = b.get_syscall_fnname("stat") |
| 118 | if BPF.ksymname(syscall_fnname) != -1: |
| 119 | b.attach_kprobe(event=syscall_fnname, fn_name="trace_entry") |
| 120 | b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return") |
Sandipan Das | 16523a3 | 2017-10-05 12:13:12 +0530 | [diff] [blame] | 121 | |
Yonghong Song | 6433569 | 2018-04-25 00:40:13 -0700 | [diff] [blame] | 122 | syscall_fnname = b.get_syscall_fnname("statfs") |
| 123 | if BPF.ksymname(syscall_fnname) != -1: |
| 124 | b.attach_kprobe(event=syscall_fnname, fn_name="trace_entry") |
| 125 | b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return") |
Sandipan Das | 16523a3 | 2017-10-05 12:13:12 +0530 | [diff] [blame] | 126 | |
Yonghong Song | 6433569 | 2018-04-25 00:40:13 -0700 | [diff] [blame] | 127 | syscall_fnname = b.get_syscall_fnname("newstat") |
| 128 | if BPF.ksymname(syscall_fnname) != -1: |
| 129 | b.attach_kprobe(event=syscall_fnname, fn_name="trace_entry") |
| 130 | b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return") |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 131 | |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 132 | TASK_COMM_LEN = 16 # linux/sched.h |
| 133 | NAME_MAX = 255 # linux/limits.h |
| 134 | |
| 135 | class Data(ct.Structure): |
| 136 | _fields_ = [ |
| 137 | ("pid", ct.c_ulonglong), |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 138 | ("ts_ns", ct.c_ulonglong), |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 139 | ("ret", ct.c_int), |
| 140 | ("comm", ct.c_char * TASK_COMM_LEN), |
| 141 | ("fname", ct.c_char * NAME_MAX) |
| 142 | ] |
| 143 | |
| 144 | start_ts = 0 |
| 145 | prev_ts = 0 |
| 146 | delta = 0 |
| 147 | |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 148 | # header |
| 149 | if args.timestamp: |
| 150 | print("%-14s" % ("TIME(s)"), end="") |
| 151 | print("%-6s %-16s %4s %3s %s" % ("PID", "COMM", "FD", "ERR", "PATH")) |
| 152 | |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 153 | # process event |
| 154 | def print_event(cpu, data, size): |
| 155 | event = ct.cast(data, ct.POINTER(Data)).contents |
| 156 | global start_ts |
| 157 | global prev_ts |
| 158 | global delta |
| 159 | global cont |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 160 | |
| 161 | # split return value into FD and errno columns |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 162 | if event.ret >= 0: |
| 163 | fd_s = event.ret |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 164 | err = 0 |
| 165 | else: |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 166 | fd_s = -1 |
| 167 | err = - event.ret |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 168 | |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 169 | if start_ts == 0: |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 170 | start_ts = event.ts_ns |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 171 | |
Brendan Gregg | ad341c9 | 2016-02-09 00:31:24 -0800 | [diff] [blame] | 172 | if args.timestamp: |
Brendan Gregg | f4ce31a | 2017-01-10 22:31:30 -0800 | [diff] [blame] | 173 | print("%-14.9f" % (float(event.ts_ns - start_ts) / 1000000000), end="") |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 174 | |
Rafael F | 78948e4 | 2017-03-26 14:54:25 +0200 | [diff] [blame] | 175 | print("%-6d %-16s %4d %3d %s" % (event.pid, event.comm.decode(), |
| 176 | fd_s, err, event.fname.decode())) |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 177 | |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 178 | # loop with callback to print_event |
Mark Drayton | 5f5687e | 2017-02-20 18:13:03 +0000 | [diff] [blame] | 179 | b["events"].open_perf_buffer(print_event, page_cnt=64) |
mcaleavya | e14f27f | 2016-02-17 22:12:44 +0000 | [diff] [blame] | 180 | while 1: |
Teng Qin | dbf0029 | 2018-02-28 21:47:50 -0800 | [diff] [blame] | 181 | b.perf_buffer_poll() |