LXR linux/tools/testing/selftests/powerpc/utils.c

   1/*
   2 * Copyright 2013-2015, Michael Ellerman, IBM Corp.
   3 * Licensed under GPLv2.
   4 */
   5
   6#include <elf.h>
   7#include <errno.h>
   8#include <fcntl.h>
   9#include <link.h>
  10#include <stdio.h>
  11#include <sys/stat.h>
  12#include <sys/types.h>
  13#include <unistd.h>
  14
  15#include "utils.h"
  16
  17static char auxv[4096];
  18
  19void *get_auxv_entry(int type)
  20{
  21        ElfW(auxv_t) *p;
  22        void *result;
  23        ssize_t num;
  24        int fd;
  25
  26        fd = open("/proc/self/auxv", O_RDONLY);
  27        if (fd == -1) {
  28                perror("open");
  29                return NULL;
  30        }
  31
  32        result = NULL;
  33
  34        num = read(fd, auxv, sizeof(auxv));
  35        if (num < 0) {
  36                perror("read");
  37                goto out;
  38        }
  39
  40        if (num > sizeof(auxv)) {
  41                printf("Overflowed auxv buffer\n");
  42                goto out;
  43        }
  44
  45        p = (ElfW(auxv_t) *)auxv;
  46
  47        while (p->a_type != AT_NULL) {
  48                if (p->a_type == type) {
  49                        result = (void *)p->a_un.a_val;
  50                        break;
  51                }
  52
  53                p++;
  54        }
  55out:
  56        close(fd);
  57        return result;
  58}
  59