1// SPDX-License-Identifier: GPL-2.0
2#include <stdio.h>
3#include <unistd.h>
4#include <stdlib.h>
5#include <signal.h>
6#include <string.h>
7
8#include <bpf/bpf.h>
9#include <bpf/libbpf.h>
10#include "bpf_util.h"
11
12#define MAX_INDEX	64
13#define MAX_STARS	38
14
15/* my_map, my_hist_map */
16static int map_fd[2];
17
18static void stars(char *str, long val, long max, int width)
19{
20	int i;
21
22	for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
23		str[i] = '*';
24	if (val > max)
25		str[i - 1] = '+';
26	str[i] = '\0';
27}
28
29struct task {
30	char comm[16];
31	__u64 pid_tgid;
32	__u64 uid_gid;
33};
34
35struct hist_key {
36	struct task t;
37	__u32 index;
38};
39
40#define SIZE sizeof(struct task)
41
42static void print_hist_for_pid(int fd, void *task)
43{
44	unsigned int nr_cpus = bpf_num_possible_cpus();
45	struct hist_key key = {}, next_key;
46	long values[nr_cpus];
47	char starstr[MAX_STARS];
48	long value;
49	long data[MAX_INDEX] = {};
50	int max_ind = -1;
51	long max_value = 0;
52	int i, ind;
53
54	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
55		if (memcmp(&next_key, task, SIZE)) {
56			key = next_key;
57			continue;
58		}
59		bpf_map_lookup_elem(fd, &next_key, values);
60		value = 0;
61		for (i = 0; i < nr_cpus; i++)
62			value += values[i];
63		ind = next_key.index;
64		data[ind] = value;
65		if (value && ind > max_ind)
66			max_ind = ind;
67		if (value > max_value)
68			max_value = value;
69		key = next_key;
70	}
71
72	printf("           syscall write() stats\n");
73	printf("     byte_size       : count     distribution\n");
74	for (i = 1; i <= max_ind + 1; i++) {
75		stars(starstr, data[i - 1], max_value, MAX_STARS);
76		printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
77		       (1l << i) >> 1, (1l << i) - 1, data[i - 1],
78		       MAX_STARS, starstr);
79	}
80}
81
82static void print_hist(int fd)
83{
84	struct hist_key key = {}, next_key;
85	static struct task tasks[1024];
86	int task_cnt = 0;
87	int i;
88
89	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
90		int found = 0;
91
92		for (i = 0; i < task_cnt; i++)
93			if (memcmp(&tasks[i], &next_key, SIZE) == 0)
94				found = 1;
95		if (!found)
96			memcpy(&tasks[task_cnt++], &next_key, SIZE);
97		key = next_key;
98	}
99
100	for (i = 0; i < task_cnt; i++) {
101		printf("\npid %d cmd %s uid %d\n",
102		       (__u32) tasks[i].pid_tgid,
103		       tasks[i].comm,
104		       (__u32) tasks[i].uid_gid);
105		print_hist_for_pid(fd, &tasks[i]);
106	}
107
108}
109
110static void int_exit(int sig)
111{
112	print_hist(map_fd[1]);
113	exit(0);
114}
115
116int main(int ac, char **argv)
117{
118	long key, next_key, value;
119	struct bpf_link *links[2];
120	struct bpf_program *prog;
121	struct bpf_object *obj;
122	char filename[256];
123	int i, j = 0;
124	FILE *f;
125
126	snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
127	obj = bpf_object__open_file(filename, NULL);
128	if (libbpf_get_error(obj)) {
129		fprintf(stderr, "ERROR: opening BPF object file failed\n");
130		return 0;
131	}
132
133	/* load BPF program */
134	if (bpf_object__load(obj)) {
135		fprintf(stderr, "ERROR: loading BPF object file failed\n");
136		goto cleanup;
137	}
138
139	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "my_map");
140	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "my_hist_map");
141	if (map_fd[0] < 0 || map_fd[1] < 0) {
142		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
143		goto cleanup;
144	}
145
146	signal(SIGINT, int_exit);
147	signal(SIGTERM, int_exit);
148
149	/* start 'ping' in the background to have some kfree_skb_reason
150	 * events */
151	f = popen("ping -4 -c5 localhost", "r");
152	(void) f;
153
154	/* start 'dd' in the background to have plenty of 'write' syscalls */
155	f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
156	(void) f;
157
158	bpf_object__for_each_program(prog, obj) {
159		links[j] = bpf_program__attach(prog);
160		if (libbpf_get_error(links[j])) {
161			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
162			links[j] = NULL;
163			goto cleanup;
164		}
165		j++;
166	}
167
168	for (i = 0; i < 5; i++) {
169		key = 0;
170		while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
171			bpf_map_lookup_elem(map_fd[0], &next_key, &value);
172			printf("location 0x%lx count %ld\n", next_key, value);
173			key = next_key;
174		}
175		if (key)
176			printf("\n");
177		sleep(1);
178	}
179	print_hist(map_fd[1]);
180
181cleanup:
182	for (j--; j >= 0; j--)
183		bpf_link__destroy(links[j]);
184
185	bpf_object__close(obj);
186	return 0;
187}
188