tools/testing/selftests/bpf/bpf_util.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __BPF_UTIL__
   3 #define __BPF_UTIL__
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <syscall.h>
  10 #include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
  11
  12 static inline unsigned int bpf_num_possible_cpus(void)
  13 {
  14         int possible_cpus = libbpf_num_possible_cpus();
  15
  16         if (possible_cpus < 0) {
  17                 printf("Failed to get # of possible cpus: '%s'!\n",
  18                        strerror(-possible_cpus));
  19                 exit(1);
  20         }
  21         return possible_cpus;
  22 }
  23
  24 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
  25  * is zero-terminated string no matter what (unless sz == 0, in which case
  26  * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
  27  * in what is returned. Given this is internal helper, it's trivial to extend
  28  * this, when necessary. Use this instead of strncpy inside libbpf source code.
  29  */
  30 static inline void bpf_strlcpy(char *dst, const char *src, size_t sz)
  31 {
  32         size_t i;
  33
  34         if (sz == 0)
  35                 return;
  36
  37         sz--;
  38         for (i = 0; i < sz && src[i]; i++)
  39                 dst[i] = src[i];
  40         dst[i] = '\0';
  41 }
  42
  43 #define __bpf_percpu_val_align  __attribute__((__aligned__(8)))
  44
  45 #define BPF_DECLARE_PERCPU(type, name)                          \
  46         struct { type v; /* padding */ } __bpf_percpu_val_align \
  47                 name[bpf_num_possible_cpus()]
  48 #define bpf_percpu(name, cpu) name[(cpu)].v
  49
  50 #ifndef ARRAY_SIZE
  51 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  52 #endif
  53
  54 #ifndef sizeof_field
  55 #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
  56 #endif
  57
  58 #ifndef offsetofend
  59 #define offsetofend(TYPE, MEMBER) \
  60         (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
  61 #endif
  62
  63 /* Availability of gettid across glibc versions is hit-and-miss, therefore
  64  * fallback to syscall in this macro and use it everywhere.
  65  */
  66 #ifndef sys_gettid
  67 #define sys_gettid() syscall(SYS_gettid)
  68 #endif
  69
  70 #ifndef ENOTSUPP
  71 #define ENOTSUPP 524
  72 #endif
  73
  74 #endif /* __BPF_UTIL__ */