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// SPDX-License-Identifier: GPL-2.0-only/* Copyright (c) 2016 Facebook */#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <signal.h>#include <linux/perf_event.h>#include <errno.h>#include <stdbool.h>#include <bpf/libbpf.h>#include <bpf/bpf.h>#include "trace_helpers.h" #define PRINT_RAW_ADDR 0 /* counts, stackmap */static int map_fd[2]; static void print_ksym(__u64 addr){	struct ksym *sym; 	if (!addr)		return;	sym = ksym_search(addr);	if (!sym) {		printf("ksym not found. Is kallsyms loaded?\n");		return;	} 	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[1], &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[1], &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 bpf_object *obj = NULL;	struct bpf_link *links[2];	struct bpf_program *prog;	int delay = 1, i = 0;	char filename[256]; 	if (load_kallsyms()) {		printf("failed to process /proc/kallsyms\n");		return 2;	} 	snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);	obj = bpf_object__open_file(filename, NULL);	if (libbpf_get_error(obj)) {		fprintf(stderr, "ERROR: opening BPF object file failed\n");		obj = NULL;		goto cleanup;	} 	/* load BPF program */	if (bpf_object__load(obj)) {		fprintf(stderr, "ERROR: loading BPF object file failed\n");		goto cleanup;	} 	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");	if (map_fd[0] < 0 || map_fd[1] < 0) {		fprintf(stderr, "ERROR: finding a map in obj file failed\n");		goto cleanup;	} 	signal(SIGINT, int_exit);	signal(SIGTERM, int_exit); 	bpf_object__for_each_program(prog, obj) {		links[i] = bpf_program__attach(prog);		if (libbpf_get_error(links[i])) {			fprintf(stderr, "ERROR: bpf_program__attach failed\n");			links[i] = NULL;			goto cleanup;		}		i++;	} 	if (argc > 1)		delay = atoi(argv[1]);	sleep(delay);	print_stacks(map_fd[0]); cleanup:	for (i--; i >= 0; i--)		bpf_link__destroy(links[i]); 	bpf_object__close(obj);	return 0;}