LXR linux/tools/testing/selftests/proc/proc-self-syscall.c

   1/*
   2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
   3 *
   4 * Permission to use, copy, modify, and distribute this software for any
   5 * purpose with or without fee is hereby granted, provided that the above
   6 * copyright notice and this permission notice appear in all copies.
   7 *
   8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15 */
  16#include <unistd.h>
  17#include <sys/syscall.h>
  18#include <sys/types.h>
  19#include <sys/stat.h>
  20#include <fcntl.h>
  21#include <errno.h>
  22#include <string.h>
  23#include <stdio.h>
  24
  25static inline ssize_t sys_read(int fd, void *buf, size_t len)
  26{
  27        return syscall(SYS_read, fd, buf, len);
  28}
  29
  30int main(void)
  31{
  32        char buf1[64];
  33        char buf2[64];
  34        int fd;
  35        ssize_t rv;
  36
  37        fd = open("/proc/self/syscall", O_RDONLY);
  38        if (fd == -1) {
  39                if (errno == ENOENT)
  40                        return 4;
  41                return 1;
  42        }
  43
  44        /* Do direct system call as libc can wrap anything. */
  45        snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx",
  46                 (long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2));
  47
  48        memset(buf2, 0, sizeof(buf2));
  49        rv = sys_read(fd, buf2, sizeof(buf2));
  50        if (rv < 0)
  51                return 1;
  52        if (rv < strlen(buf1))
  53                return 1;
  54        if (strncmp(buf1, buf2, strlen(buf1)) != 0)
  55                return 1;
  56
  57        return 0;
  58}
  59