samples/bpf/spintest_user.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <string.h>
   5 #include <assert.h>
   6 #include <sys/resource.h>
   7 #include <bpf/libbpf.h>
   8 #include <bpf/bpf.h>
   9 #include "trace_helpers.h"
  10
  11 int main(int ac, char **argv)
  12 {
  13         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  14         char filename[256], symbol[256];
  15         struct bpf_object *obj = NULL;
  16         struct bpf_link *links[20];
  17         long key, next_key, value;
  18         struct bpf_program *prog;
  19         int map_fd, i, j = 0;
  20         const char *section;
  21         struct ksym *sym;
  22
  23         if (setrlimit(RLIMIT_MEMLOCK, &r)) {
  24                 perror("setrlimit(RLIMIT_MEMLOCK)");
  25                 return 1;
  26         }
  27
  28         if (load_kallsyms()) {
  29                 printf("failed to process /proc/kallsyms\n");
  30                 return 2;
  31         }
  32
  33         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  34         obj = bpf_object__open_file(filename, NULL);
  35         if (libbpf_get_error(obj)) {
  36                 fprintf(stderr, "ERROR: opening BPF object file failed\n");
  37                 obj = NULL;
  38                 goto cleanup;
  39         }
  40
  41         /* load BPF program */
  42         if (bpf_object__load(obj)) {
  43                 fprintf(stderr, "ERROR: loading BPF object file failed\n");
  44                 goto cleanup;
  45         }
  46
  47         map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
  48         if (map_fd < 0) {
  49                 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
  50                 goto cleanup;
  51         }
  52
  53         bpf_object__for_each_program(prog, obj) {
  54                 section = bpf_program__section_name(prog);
  55                 if (sscanf(section, "kprobe/%s", symbol) != 1)
  56                         continue;
  57
  58                 /* Attach prog only when symbol exists */
  59                 if (ksym_get_addr(symbol)) {
  60                         links[j] = bpf_program__attach(prog);
  61                         if (libbpf_get_error(links[j])) {
  62                                 fprintf(stderr, "bpf_program__attach failed\n");
  63                                 links[j] = NULL;
  64                                 goto cleanup;
  65                         }
  66                         j++;
  67                 }
  68         }
  69
  70         for (i = 0; i < 5; i++) {
  71                 key = 0;
  72                 printf("kprobing funcs:");
  73                 while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) {
  74                         bpf_map_lookup_elem(map_fd, &next_key, &value);
  75                         assert(next_key == value);
  76                         sym = ksym_search(value);
  77                         key = next_key;
  78                         if (!sym) {
  79                                 printf("ksym not found. Is kallsyms loaded?\n");
  80                                 continue;
  81                         }
  82
  83                         printf(" %s", sym->name);
  84                 }
  85                 if (key)
  86                         printf("\n");
  87                 key = 0;
  88                 while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0)
  89                         bpf_map_delete_elem(map_fd, &next_key);
  90                 sleep(1);
  91         }
  92
  93 cleanup:
  94         for (j--; j >= 0; j--)
  95                 bpf_link__destroy(links[j]);
  96
  97         bpf_object__close(obj);
  98         return 0;
  99 }