1  /*
       2   * Check decoding of readlinkat syscall.
       3   *
       4   * Copyright (c) 2015 Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
       5   * Copyright (c) 2015-2018 Dmitry V. Levin <ldv@strace.io>
       6   * Copyright (c) 2015-2021 The strace developers.
       7   * All rights reserved.
       8   *
       9   * SPDX-License-Identifier: GPL-2.0-or-later
      10   */
      11  
      12  #include "tests.h"
      13  #include "scno.h"
      14  
      15  #include <stdio.h>
      16  #include <unistd.h>
      17  
      18  #define PREFIX "test.readlinkat"
      19  #define TARGET (PREFIX ".target")
      20  #define LINKPATH (PREFIX ".link")
      21  
      22  int
      23  main(void)
      24  {
      25  	const char * const fname = tail_memdup(LINKPATH, sizeof(LINKPATH));
      26  	const char * const hex_fname =
      27  		hexquote_strndup(fname, sizeof(LINKPATH) - 1);
      28  
      29  	const unsigned int size = sizeof(TARGET) - 1;
      30  	char * const buf = tail_alloc(size);
      31  
      32  	(void) unlink(fname);
      33  
      34  	long rc = syscall(__NR_readlinkat, -100, fname, buf, size);
      35  	printf("readlinkat(AT_FDCWD, \"%s\", %p, %u) = -1 ENOENT (%m)\n",
      36  	       hex_fname, buf, size);
      37  
      38  	if (symlink(TARGET, fname))
      39  		perror_msg_and_fail("symlink");
      40  
      41  	rc = syscall(__NR_readlinkat, -100, fname, buf, size);
      42  	if (rc < 0) {
      43  		perror("readlinkat");
      44  		(void) unlink(fname);
      45  		return 77;
      46  	}
      47  	const char * const hex_buf = hexquote_strndup(buf, size);
      48  	printf("readlinkat(AT_FDCWD, \"%s\", \"%s\", %u) = %u\n",
      49  	       hex_fname, hex_buf, size, size);
      50  
      51  	if (unlink(fname))
      52  		perror_msg_and_fail("unlink");
      53  
      54  	puts("+++ exited with 0 +++");
      55  	return 0;
      56  }