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