1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright (c) 2016 Facebook
  3 */
  4#include <stdio.h>
  5#include <unistd.h>
  6#include <stdlib.h>
  7#include <signal.h>
  8#include <linux/perf_event.h>
  9#include <errno.h>
 10#include <stdbool.h>
 11#include <bpf/libbpf.h>
 12#include <bpf/bpf.h>
 13#include "trace_helpers.h"
 14
 15#define PRINT_RAW_ADDR 0
 16
 17/* counts, stackmap */
 18static int map_fd[2];
 19
 20static void print_ksym(__u64 addr)
 21{
 22	struct ksym *sym;
 23
 24	if (!addr)
 25		return;
 26	sym = ksym_search(addr);
 27	if (!sym) {
 28		printf("ksym not found. Is kallsyms loaded?\n");
 29		return;
 30	}
 31
 32	if (PRINT_RAW_ADDR)
 33		printf("%s/%llx;", sym->name, addr);
 34	else
 35		printf("%s;", sym->name);
 36}
 37
 38#define TASK_COMM_LEN 16
 39
 40struct key_t {
 41	char waker[TASK_COMM_LEN];
 42	char target[TASK_COMM_LEN];
 43	__u32 wret;
 44	__u32 tret;
 45};
 46
 47static void print_stack(struct key_t *key, __u64 count)
 48{
 49	__u64 ip[PERF_MAX_STACK_DEPTH] = {};
 50	static bool warned;
 51	int i;
 52
 53	printf("%s;", key->target);
 54	if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
 55		printf("---;");
 56	} else {
 57		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
 58			print_ksym(ip[i]);
 59	}
 60	printf("-;");
 61	if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {
 62		printf("---;");
 63	} else {
 64		for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
 65			print_ksym(ip[i]);
 66	}
 67	printf(";%s %lld\n", key->waker, count);
 68
 69	if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {
 70		printf("stackmap collisions seen. Consider increasing size\n");
 71		warned = true;
 72	} else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {
 73		printf("err stackid %d %d\n", key->tret, key->wret);
 74	}
 75}
 76
 77static void print_stacks(int fd)
 78{
 79	struct key_t key = {}, next_key;
 80	__u64 value;
 81
 82	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
 83		bpf_map_lookup_elem(fd, &next_key, &value);
 84		print_stack(&next_key, value);
 85		key = next_key;
 86	}
 87}
 88
 89static void int_exit(int sig)
 90{
 91	print_stacks(map_fd[0]);
 92	exit(0);
 93}
 94
 95int main(int argc, char **argv)
 96{
 97	struct bpf_object *obj = NULL;
 98	struct bpf_link *links[2];
 99	struct bpf_program *prog;
100	int delay = 1, i = 0;
101	char filename[256];
102
103	if (load_kallsyms()) {
104		printf("failed to process /proc/kallsyms\n");
105		return 2;
106	}
107
108	snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
109	obj = bpf_object__open_file(filename, NULL);
110	if (libbpf_get_error(obj)) {
111		fprintf(stderr, "ERROR: opening BPF object file failed\n");
112		obj = NULL;
113		goto cleanup;
114	}
115
116	/* load BPF program */
117	if (bpf_object__load(obj)) {
118		fprintf(stderr, "ERROR: loading BPF object file failed\n");
119		goto cleanup;
120	}
121
122	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
123	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
124	if (map_fd[0] < 0 || map_fd[1] < 0) {
125		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
126		goto cleanup;
127	}
128
129	signal(SIGINT, int_exit);
130	signal(SIGTERM, int_exit);
131
132	bpf_object__for_each_program(prog, obj) {
133		links[i] = bpf_program__attach(prog);
134		if (libbpf_get_error(links[i])) {
135			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
136			links[i] = NULL;
137			goto cleanup;
138		}
139		i++;
140	}
141
142	if (argc > 1)
143		delay = atoi(argv[1]);
144	sleep(delay);
145	print_stacks(map_fd[0]);
146
147cleanup:
148	for (i--; i >= 0; i--)
149		bpf_link__destroy(links[i]);
150
151	bpf_object__close(obj);
152	return 0;
153}