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         unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
  41         long values[nr_cpus];
  42         char starstr[MAX_STARS];
  43         long value;
  44         long data[MAX_INDEX] = {};
  45         int max_ind = -1;
  46         long max_value = 0;
  47         int i, ind;
  48
  49         while (bpf_get_next_key(fd, &key, &next_key) == 0) {
  50                 if (memcmp(&next_key, task, SIZE)) {
  51                         key = next_key;
  52                         continue;
  53                 }
  54                 bpf_lookup_elem(fd, &next_key, values);
  55                 value = 0;
  56                 for (i = 0; i < nr_cpus; i++)
  57                         value += values[i];
  58                 ind = next_key.index;
  59                 data[ind] = value;
  60                 if (value && ind > max_ind)
  61                         max_ind = ind;
  62                 if (value > max_value)
  63                         max_value = value;
  64                 key = next_key;
  65         }
  66
  67         printf("           syscall write() stats\n");
  68         printf("     byte_size       : count     distribution\n");
  69         for (i = 1; i <= max_ind + 1; i++) {
  70                 stars(starstr, data[i - 1], max_value, MAX_STARS);
  71                 printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
  72                        (1l << i) >> 1, (1l << i) - 1, data[i - 1],
  73                        MAX_STARS, starstr);
  74         }
  75 }
  76
  77 static void print_hist(int fd)
  78 {
  79         struct hist_key key = {}, next_key;
  80         static struct task tasks[1024];
  81         int task_cnt = 0;
  82         int i;
  83
  84         while (bpf_get_next_key(fd, &key, &next_key) == 0) {
  85                 int found = 0;
  86
  87                 for (i = 0; i < task_cnt; i++)
  88                         if (memcmp(&tasks[i], &next_key, SIZE) == 0)
  89                                 found = 1;
  90                 if (!found)
  91                         memcpy(&tasks[task_cnt++], &next_key, SIZE);
  92                 key = next_key;
  93         }
  94
  95         for (i = 0; i < task_cnt; i++) {
  96                 printf("\npid %d cmd %s uid %d\n",
  97                        (__u32) tasks[i].pid_tgid,
  98                        tasks[i].comm,
  99                        (__u32) tasks[i].uid_gid);
 100                 print_hist_for_pid(fd, &tasks[i]);
 101         }
 102
 103 }
 104
 105 static void int_exit(int sig)
 106 {
 107         print_hist(map_fd[1]);
 108         exit(0);
 109 }
 110
 111 int main(int ac, char **argv)
 112 {
 113         char filename[256];
 114         long key, next_key, value;
 115         FILE *f;
 116         int i;
 117
 118         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 119
 120         signal(SIGINT, int_exit);
 121
 122         /* start 'ping' in the background to have some kfree_skb events */
 123         f = popen("ping -c5 localhost", "r");
 124         (void) f;
 125
 126         /* start 'dd' in the background to have plenty of 'write' syscalls */
 127         f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
 128         (void) f;
 129
 130         if (load_bpf_file(filename)) {
 131                 printf("%s", bpf_log_buf);
 132                 return 1;
 133         }
 134
 135         for (i = 0; i < 5; i++) {
 136                 key = 0;
 137                 while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) {
 138                         bpf_lookup_elem(map_fd[0], &next_key, &value);
 139                         printf("location 0x%lx count %ld\n", next_key, value);
 140                         key = next_key;
 141                 }
 142                 if (key)
 143                         printf("\n");
 144                 sleep(1);
 145         }
 146         print_hist(map_fd[1]);
 147
 148         return 0;
 149 }