tools/testing/selftests/bpf/bpf_util.h

   1 #ifndef __BPF_UTIL__
   2 #define __BPF_UTIL__
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <errno.h>
   8
   9 static inline unsigned int bpf_num_possible_cpus(void)
  10 {
  11         static const char *fcpu = "/sys/devices/system/cpu/possible";
  12         unsigned int start, end, possible_cpus = 0;
  13         char buff[128];
  14         FILE *fp;
  15
  16         fp = fopen(fcpu, "r");
  17         if (!fp) {
  18                 printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
  19                 exit(1);
  20         }
  21
  22         while (fgets(buff, sizeof(buff), fp)) {
  23                 if (sscanf(buff, "%u-%u", &start, &end) == 2) {
  24                         possible_cpus = start == 0 ? end + 1 : 0;
  25                         break;
  26                 }
  27         }
  28
  29         fclose(fp);
  30         if (!possible_cpus) {
  31                 printf("Failed to retrieve # possible CPUs!\n");
  32                 exit(1);
  33         }
  34
  35         return possible_cpus;
  36 }
  37
  38 #endif /* __BPF_UTIL__ */