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 #include <asm/byteorder.h>
  10
  11 #if __BYTE_ORDER == __LITTLE_ENDIAN
  12 # define __bpf_ntohs(x)         __builtin_bswap16(x)
  13 # define __bpf_htons(x)         __builtin_bswap16(x)
  14 #elif __BYTE_ORDER == __BIG_ENDIAN
  15 # define __bpf_ntohs(x)         (x)
  16 # define __bpf_htons(x)         (x)
  17 #else
  18 # error "Fix your __BYTE_ORDER?!"
  19 #endif
  20
  21 #define bpf_htons(x)                            \
  22         (__builtin_constant_p(x) ?              \
  23          __constant_htons(x) : __bpf_htons(x))
  24 #define bpf_ntohs(x)                            \
  25         (__builtin_constant_p(x) ?              \
  26          __constant_ntohs(x) : __bpf_ntohs(x))
  27
  28 static inline unsigned int bpf_num_possible_cpus(void)
  29 {
  30         static const char *fcpu = "/sys/devices/system/cpu/possible";
  31         unsigned int start, end, possible_cpus = 0;
  32         char buff[128];
  33         FILE *fp;
  34
  35         fp = fopen(fcpu, "r");
  36         if (!fp) {
  37                 printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
  38                 exit(1);
  39         }
  40
  41         while (fgets(buff, sizeof(buff), fp)) {
  42                 if (sscanf(buff, "%u-%u", &start, &end) == 2) {
  43                         possible_cpus = start == 0 ? end + 1 : 0;
  44                         break;
  45                 }
  46         }
  47
  48         fclose(fp);
  49         if (!possible_cpus) {
  50                 printf("Failed to retrieve # possible CPUs!\n");
  51                 exit(1);
  52         }
  53
  54         return possible_cpus;
  55 }
  56
  57 #endif /* __BPF_UTIL__ */