/* Copyright (c) 2016 Facebook * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <signal.h>#include <linux/bpf.h>#include <string.h>#include <linux/perf_event.h>#include <errno.h>#include <assert.h>#include <stdbool.h>#include <sys/resource.h>#include "libbpf.h"#include "bpf_load.h" #define PRINT_RAW_ADDR 0 static void print_ksym(__u64 addr){	struct ksym *sym; 	if (!addr)		return;	sym = ksym_search(addr);	if (PRINT_RAW_ADDR)		printf("%s/%llx;", sym->name, addr);	else		printf("%s;", sym->name);} #define TASK_COMM_LEN 16 struct key_t {	char waker[TASK_COMM_LEN];	char target[TASK_COMM_LEN];	__u32 wret;	__u32 tret;}; static void print_stack(struct key_t *key, __u64 count){	__u64 ip[PERF_MAX_STACK_DEPTH] = {};	static bool warned;	int i; 	printf("%s;", key->target);	if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) {		printf("---;");	} else {		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)			print_ksym(ip[i]);	}	printf("-;");	if (bpf_map_lookup_elem(map_fd[3], &key->wret, ip) != 0) {		printf("---;");	} else {		for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)			print_ksym(ip[i]);	}	printf(";%s %lld\n", key->waker, count); 	if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {		printf("stackmap collisions seen. Consider increasing size\n");		warned = true;	} else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {		printf("err stackid %d %d\n", key->tret, key->wret);	}} static void print_stacks(int fd){	struct key_t key = {}, next_key;	__u64 value; 	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {		bpf_map_lookup_elem(fd, &next_key, &value);		print_stack(&next_key, value);		key = next_key;	}} static void int_exit(int sig){	print_stacks(map_fd[0]);	exit(0);} int main(int argc, char **argv){	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};	char filename[256];	int delay = 1; 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);	setrlimit(RLIMIT_MEMLOCK, &r); 	signal(SIGINT, int_exit);	signal(SIGTERM, int_exit); 	if (load_kallsyms()) {		printf("failed to process /proc/kallsyms\n");		return 2;	} 	if (load_bpf_file(filename)) {		printf("%s", bpf_log_buf);		return 1;	} 	if (argc > 1)		delay = atoi(argv[1]);	sleep(delay);	print_stacks(map_fd[0]); 	return 0;}