samples/bpf/tracex2_user.c

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