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// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_util.h"
#define MAX_INDEX 64
#define MAX_STARS 38
/* my_map, my_hist_map */
static int map_fd[2];
static void stars(char *str, long val, long max, int width)
{
int i;
for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
str[i] = '*';
if (val > max)
str[i - 1] = '+';
str[i] = '\0';
}
struct task {
char comm[16];
__u64 pid_tgid;
__u64 uid_gid;
};
struct hist_key {
struct task t;
__u32 index;
};
#define SIZE sizeof(struct task)
static void print_hist_for_pid(int fd, void *task)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
struct hist_key key = {}, next_key;
long values[nr_cpus];
char starstr[MAX_STARS];
long value;
long data[MAX_INDEX] = {};
int max_ind = -1;
long max_value = 0;
int i, ind;
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
if (memcmp(&next_key, task, SIZE)) {
key = next_key;
continue;
}
bpf_map_lookup_elem(fd, &next_key, values);
value = 0;
for (i = 0; i < nr_cpus; i++)
value += values[i];
ind = next_key.index;
data[ind] = value;
if (value && ind > max_ind)
max_ind = ind;
if (value > max_value)
max_value = value;
key = next_key;
}
printf(" syscall write() stats\n");
printf(" byte_size : count distribution\n");
for (i = 1; i <= max_ind + 1; i++) {
stars(starstr, data[i - 1], max_value, MAX_STARS);
printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
(1l << i) >> 1, (1l << i) - 1, data[i - 1],
MAX_STARS, starstr);
}
}
static void print_hist(int fd)
{
struct hist_key key = {}, next_key;
static struct task tasks[1024];
int task_cnt = 0;
int i;
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
int found = 0;
for (i = 0; i < task_cnt; i++)
if (memcmp(&tasks[i], &next_key, SIZE) == 0)
found = 1;
if (!found)
memcpy(&tasks[task_cnt++], &next_key, SIZE);
key = next_key;
}
for (i = 0; i < task_cnt; i++) {
printf("\npid %d cmd %s uid %d\n",
(__u32) tasks[i].pid_tgid,
tasks[i].comm,
(__u32) tasks[i].uid_gid);
print_hist_for_pid(fd, &tasks[i]);
}
}
static void int_exit(int sig)
{
print_hist(map_fd[1]);
exit(0);
}
int main(int ac, char **argv)
{
long key, next_key, value;
struct bpf_link *links[2];
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
int i, j = 0;
FILE *f;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
/* 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, "my_map");
map_fd[1] = bpf_object__find_map_fd_by_name(obj, "my_hist_map");
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);
/* start 'ping' in the background to have some kfree_skb events */
f = popen("ping -4 -c5 localhost", "r");
(void) f;
/* start 'dd' in the background to have plenty of 'write' syscalls */
f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
(void) f;
bpf_object__for_each_program(prog, obj) {
links[j] = bpf_program__attach(prog);
if (libbpf_get_error(links[j])) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[j] = NULL;
goto cleanup;
}
j++;
}
for (i = 0; i < 5; i++) {
key = 0;
while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
bpf_map_lookup_elem(map_fd[0], &next_key, &value);
printf("location 0x%lx count %ld\n", next_key, value);
key = next_key;
}
if (key)
printf("\n");
sleep(1);
}
print_hist(map_fd[1]);
cleanup:
for (j--; j >= 0; j--)
bpf_link__destroy(links[j]);
bpf_object__close(obj);
return 0;
}
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