LXR linux/samples/bpf/tracex2

   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 <linux/bpf.h>
   7#include <string.h>
   8#include <sys/resource.h>
   9
  10#include <bpf/bpf.h>
  11#include "bpf_load.h"
  12#include "bpf_util.h"
  13
  14#define MAX_INDEX       64
  15#define MAX_STARS       38
  16
  17static void stars(char *str, long val, long max, int width)
  18{
  19        int i;
  20
  21        for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
  22                str[i] = '*';
  23        if (val > max)
  24                str[i - 1] = '+';
  25        str[i] = '\0';
  26}
  27
  28struct task {
  29        char comm[16];
  30        __u64 pid_tgid;
  31        __u64 uid_gid;
  32};
  33
  34struct hist_key {
  35        struct task t;
  36        __u32 index;
  37};
  38
  39#define SIZE sizeof(struct task)
  40
  41static void print_hist_for_pid(int fd, void *task)
  42{
  43        unsigned int nr_cpus = bpf_num_possible_cpus();
  44        struct hist_key key = {}, next_key;
  45        long values[nr_cpus];
  46        char starstr[MAX_STARS];
  47        long value;
  48        long data[MAX_INDEX] = {};
  49        int max_ind = -1;
  50        long max_value = 0;
  51        int i, ind;
  52
  53        while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
  54                if (memcmp(&next_key, task, SIZE)) {
  55                        key = next_key;
  56                        continue;
  57                }
  58                bpf_map_lookup_elem(fd, &next_key, values);
  59                value = 0;
  60                for (i = 0; i < nr_cpus; i++)
  61                        value += values[i];
  62                ind = next_key.index;
  63                data[ind] = value;
  64                if (value && ind > max_ind)
  65                        max_ind = ind;
  66                if (value > max_value)
  67                        max_value = value;
  68                key = next_key;
  69        }
  70
  71        printf("           syscall write() stats\n");
  72        printf("     byte_size       : count     distribution\n");
  73        for (i = 1; i <= max_ind + 1; i++) {
  74                stars(starstr, data[i - 1], max_value, MAX_STARS);
  75                printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
  76                       (1l << i) >> 1, (1l << i) - 1, data[i - 1],
  77                       MAX_STARS, starstr);
  78        }
  79}
  80
  81static void print_hist(int fd)
  82{
  83        struct hist_key key = {}, next_key;
  84        static struct task tasks[1024];
  85        int task_cnt = 0;
  86        int i;
  87
  88        while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
  89                int found = 0;
  90
  91                for (i = 0; i < task_cnt; i++)
  92                        if (memcmp(&tasks[i], &next_key, SIZE) == 0)
  93                                found = 1;
  94                if (!found)
  95                        memcpy(&tasks[task_cnt++], &next_key, SIZE);
  96                key = next_key;
  97        }
  98
  99        for (i = 0; i < task_cnt; i++) {
 100                printf("\npid %d cmd %s uid %d\n",
 101                       (__u32) tasks[i].pid_tgid,
 102                       tasks[i].comm,
 103                       (__u32) tasks[i].uid_gid);
 104                print_hist_for_pid(fd, &tasks[i]);
 105        }
 106
 107}
 108
 109static void int_exit(int sig)
 110{
 111        print_hist(map_fd[1]);
 112        exit(0);
 113}
 114
 115int main(int ac, char **argv)
 116{
 117        struct rlimit r = {1024*1024, RLIM_INFINITY};
 118        char filename[256];
 119        long key, next_key, value;
 120        FILE *f;
 121        int i;
 122
 123        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 124
 125        if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 126                perror("setrlimit(RLIMIT_MEMLOCK)");
 127                return 1;
 128        }
 129
 130        signal(SIGINT, int_exit);
 131        signal(SIGTERM, int_exit);
 132
 133        /* start 'ping' in the background to have some kfree_skb events */
 134        f = popen("ping -4 -c5 localhost", "r");
 135        (void) f;
 136
 137        /* start 'dd' in the background to have plenty of 'write' syscalls */
 138        f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
 139        (void) f;
 140
 141        if (load_bpf_file(filename)) {
 142                printf("%s", bpf_log_buf);
 143                return 1;
 144        }
 145
 146        for (i = 0; i < 5; i++) {
 147                key = 0;
 148                while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
 149                        bpf_map_lookup_elem(map_fd[0], &next_key, &value);
 150                        printf("location 0x%lx count %ld\n", next_key, value);
 151                        key = next_key;
 152                }
 153                if (key)
 154                        printf("\n");
 155                sleep(1);
 156        }
 157        print_hist(map_fd[1]);
 158
 159        return 0;
 160}
 161