349 lines
8.0 KiB
C
349 lines
8.0 KiB
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/* Copyright (c) 2021 Google LLC.
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*
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* Based on funclatency from BCC by Brendan Gregg and others
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* 2021-02-26 Barret Rhoden Created this.
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*
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* TODO:
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* - support uprobes on libraries without -p PID. (parse ld.so.cache)
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* - support regexp pattern matching and per-function histograms
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*/
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#include <argp.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <bpf/libbpf.h>
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#include <bpf/bpf.h>
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#include "funclatency.h"
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#include "funclatency.skel.h"
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#include "trace_helpers.h"
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#include "map_helpers.h"
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#include "uprobe_helpers.h"
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#define warn(...) fprintf(stderr, __VA_ARGS__)
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static struct prog_env {
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int units;
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pid_t pid;
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unsigned int duration;
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unsigned int interval;
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unsigned int iterations;
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bool timestamp;
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char *funcname;
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bool verbose;
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} env = {
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.interval = 99999999,
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.iterations = 99999999,
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};
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const char *argp_program_version = "funclatency 0.1";
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const char *argp_program_bug_address =
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"https://github.com/iovisor/bcc/tree/master/libbpf-tools";
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static const char args_doc[] = "FUNCTION";
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static const char program_doc[] =
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"Time functions and print latency as a histogram\n"
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"\n"
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"Usage: funclatency [-h] [-m|-u] [-p PID] [-d DURATION] [ -i INTERVAL ]\n"
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" [-T] FUNCTION\n"
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" Choices for FUNCTION: FUNCTION (kprobe)\n"
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" LIBRARY:FUNCTION (uprobe a library in -p PID)\n"
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" :FUNCTION (uprobe the binary of -p PID)\n"
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" PROGRAM:FUNCTION (uprobe the binary PROGRAM)\n"
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"\v"
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"Examples:\n"
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" ./funclatency do_sys_open # time the do_sys_open() kernel function\n"
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" ./funclatency -m do_nanosleep # time do_nanosleep(), in milliseconds\n"
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" ./funclatency -u vfs_read # time vfs_read(), in microseconds\n"
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" ./funclatency -p 181 vfs_read # time process 181 only\n"
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" ./funclatency -p 181 c:read # time the read() C library function\n"
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" ./funclatency -p 181 :foo # time foo() from pid 181's userspace\n"
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" ./funclatency -i 2 -d 10 vfs_read # output every 2 seconds, for 10s\n"
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" ./funclatency -mTi 5 vfs_read # output every 5 seconds, with timestamps\n"
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;
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static const struct argp_option opts[] = {
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{ "milliseconds", 'm', NULL, 0, "Output in milliseconds"},
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{ "microseconds", 'u', NULL, 0, "Output in microseconds"},
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{0, 0, 0, 0, ""},
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{ "pid", 'p', "PID", 0, "Process ID to trace"},
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{0, 0, 0, 0, ""},
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{ "interval", 'i', "INTERVAL", 0, "Summary interval in seconds"},
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{ "duration", 'd', "DURATION", 0, "Duration to trace"},
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{ "timestamp", 'T', NULL, 0, "Print timestamp"},
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{ "verbose", 'v', NULL, 0, "Verbose debug output" },
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{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help"},
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{},
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};
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static error_t parse_arg(int key, char *arg, struct argp_state *state)
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{
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struct prog_env *env = state->input;
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long duration, interval, pid;
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switch (key) {
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case 'p':
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errno = 0;
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pid = strtol(arg, NULL, 10);
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if (errno || pid <= 0) {
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warn("Invalid PID: %s\n", arg);
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argp_usage(state);
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}
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env->pid = pid;
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break;
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case 'm':
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if (env->units != NSEC) {
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warn("only set one of -m or -u\n");
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argp_usage(state);
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}
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env->units = MSEC;
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break;
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case 'u':
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if (env->units != NSEC) {
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warn("only set one of -m or -u\n");
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argp_usage(state);
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}
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env->units = USEC;
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break;
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case 'd':
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errno = 0;
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duration = strtol(arg, NULL, 10);
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if (errno || duration <= 0) {
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warn("Invalid duration: %s\n", arg);
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argp_usage(state);
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}
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env->duration = duration;
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break;
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case 'i':
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errno = 0;
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interval = strtol(arg, NULL, 10);
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if (errno || interval <= 0) {
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warn("Invalid interval: %s\n", arg);
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argp_usage(state);
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}
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env->interval = interval;
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break;
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case 'T':
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env->timestamp = true;
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break;
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case 'v':
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env->verbose = true;
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break;
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case 'h':
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argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
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break;
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case ARGP_KEY_ARG:
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if (env->funcname) {
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warn("Too many function names: %s\n", arg);
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argp_usage(state);
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}
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env->funcname = arg;
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break;
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case ARGP_KEY_END:
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if (!env->funcname) {
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warn("Need a function to trace\n");
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argp_usage(state);
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}
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if (env->duration) {
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if (env->interval > env->duration)
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env->interval = env->duration;
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env->iterations = env->duration / env->interval;
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}
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break;
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default:
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return ARGP_ERR_UNKNOWN;
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}
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return 0;
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}
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static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
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{
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if (level == LIBBPF_DEBUG && !env.verbose)
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return 0;
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return vfprintf(stderr, format, args);
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}
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static const char *unit_str(void)
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{
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switch (env.units) {
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case NSEC:
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return "nsec";
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case USEC:
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return "usec";
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case MSEC:
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return "msec";
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};
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return "bad units";
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}
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static int attach_kprobes(struct funclatency_bpf *obj)
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{
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long err;
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obj->links.dummy_kprobe = bpf_program__attach_kprobe(obj->progs.dummy_kprobe, false,
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env.funcname);
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if (!obj->links.dummy_kprobe) {
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err = -errno;
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warn("failed to attach kprobe: %ld\n", err);
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return -1;
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}
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obj->links.dummy_kretprobe = bpf_program__attach_kprobe(obj->progs.dummy_kretprobe, true,
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env.funcname);
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if (!obj->links.dummy_kretprobe) {
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err = -errno;
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warn("failed to attach kretprobe: %ld\n", err);
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return -1;
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}
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return 0;
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}
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static int attach_uprobes(struct funclatency_bpf *obj)
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{
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char *binary, *function;
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char bin_path[PATH_MAX];
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off_t func_off;
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int ret = -1;
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long err;
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binary = strdup(env.funcname);
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if (!binary) {
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warn("strdup failed");
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return -1;
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}
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function = strchr(binary, ':');
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if (!function) {
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warn("Binary should have contained ':' (internal bug!)\n");
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return -1;
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}
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*function = '\0';
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function++;
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if (resolve_binary_path(binary, env.pid, bin_path, sizeof(bin_path)))
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goto out_binary;
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func_off = get_elf_func_offset(bin_path, function);
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if (func_off < 0) {
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warn("Could not find %s in %s\n", function, bin_path);
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goto out_binary;
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}
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obj->links.dummy_kprobe =
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bpf_program__attach_uprobe(obj->progs.dummy_kprobe, false,
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env.pid ?: -1, bin_path, func_off);
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if (!obj->links.dummy_kprobe) {
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err = -errno;
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warn("Failed to attach uprobe: %ld\n", err);
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goto out_binary;
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}
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obj->links.dummy_kretprobe =
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bpf_program__attach_uprobe(obj->progs.dummy_kretprobe, true,
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env.pid ?: -1, bin_path, func_off);
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if (!obj->links.dummy_kretprobe) {
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err = -errno;
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warn("Failed to attach uretprobe: %ld\n", err);
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goto out_binary;
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}
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ret = 0;
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out_binary:
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free(binary);
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return ret;
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}
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static int attach_probes(struct funclatency_bpf *obj)
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{
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if (strchr(env.funcname, ':'))
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return attach_uprobes(obj);
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return attach_kprobes(obj);
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}
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static volatile bool exiting;
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static void sig_hand(int signr)
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{
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exiting = true;
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}
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static struct sigaction sigact = {.sa_handler = sig_hand};
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int main(int argc, char **argv)
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{
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static const struct argp argp = {
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.options = opts,
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.parser = parse_arg,
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.args_doc = args_doc,
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.doc = program_doc,
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};
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struct funclatency_bpf *obj;
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int i, err;
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struct tm *tm;
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char ts[32];
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time_t t;
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err = argp_parse(&argp, argc, argv, 0, NULL, &env);
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if (err)
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return err;
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sigaction(SIGINT, &sigact, 0);
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libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
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libbpf_set_print(libbpf_print_fn);
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obj = funclatency_bpf__open();
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if (!obj) {
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warn("failed to open BPF object\n");
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return 1;
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}
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obj->rodata->units = env.units;
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obj->rodata->targ_tgid = env.pid;
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err = funclatency_bpf__load(obj);
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if (err) {
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warn("failed to load BPF object\n");
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return 1;
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}
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if (!obj->bss) {
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warn("Memory-mapping BPF maps is supported starting from Linux 5.7, please upgrade.\n");
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goto cleanup;
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}
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err = attach_probes(obj);
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if (err)
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goto cleanup;
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printf("Tracing %s. Hit Ctrl-C to exit\n", env.funcname);
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for (i = 0; i < env.iterations && !exiting; i++) {
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sleep(env.interval);
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printf("\n");
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if (env.timestamp) {
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time(&t);
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tm = localtime(&t);
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strftime(ts, sizeof(ts), "%H:%M:%S", tm);
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printf("%-8s\n", ts);
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}
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print_log2_hist(obj->bss->hist, MAX_SLOTS, unit_str());
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}
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printf("Exiting trace of %s\n", env.funcname);
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cleanup:
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funclatency_bpf__destroy(obj);
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return err != 0;
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}
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