root/samples/bpf/tracex2_user.c

DEFINITIONS

1. stars
2. print_hist
3. int_exit
4. main

   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 
  17 static 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 
  28 struct task {
  29         char comm[16];
  30         __u64 pid_tgid;
  31         __u64 uid_gid;
  32 };
  33 
  34 struct hist_key {
  35         struct task t;
  36         __u32 index;
  37 };
  38 
  39 #define SIZE sizeof(struct task)
  40 
  41 static 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 
  81 static 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 
 109 static void int_exit(int sig)
 110 {
 111         print_hist(map_fd[1]);
 112         exit(0);
 113 }
 114 
 115 int 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 }