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 #define _GNU_SOURCE
  17 #include <unistd.h>
  18 #include <sys/syscall.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <fcntl.h>
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <stdio.h>
  25
  26 static inline ssize_t sys_read(int fd, void *buf, size_t len)
  27 {
  28         return syscall(SYS_read, fd, buf, len);
  29 }
  30
  31 int main(void)
  32 {
  33         char buf1[64];
  34         char buf2[64];
  35         int fd;
  36         ssize_t rv;
  37
  38         fd = open("/proc/self/syscall", O_RDONLY);
  39         if (fd == -1) {
  40                 if (errno == ENOENT)
  41                         return 4;
  42                 return 1;
  43         }
  44
  45         /* Do direct system call as libc can wrap anything. */
  46         snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx",
  47                  (long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2));
  48
  49         memset(buf2, 0, sizeof(buf2));
  50         rv = sys_read(fd, buf2, sizeof(buf2));
  51         if (rv < 0)
  52                 return 1;
  53         if (rv < strlen(buf1))
  54                 return 1;
  55         if (strncmp(buf1, buf2, strlen(buf1)) != 0)
  56                 return 1;
  57
  58         return 0;
  59 }