samples/bpf/tracex2_user.c

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