1  /*
       2   * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
       3   * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
       4   * Copyright (c) 1993-1996 Rick Sladkey <jrs@world.std.com>
       5   * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
       6   * Copyright (c) 2006 Ulrich Drepper <drepper@redhat.com>
       7   * Copyright (c) 2006 Bernhard Kaindl <bk@suse.de>
       8   * Copyright (c) 2006-2015 Dmitry V. Levin <ldv@strace.io>
       9   * Copyright (c) 2014-2021 The strace developers.
      10   * All rights reserved.
      11   *
      12   * SPDX-License-Identifier: LGPL-2.1-or-later
      13   */
      14  
      15  #include "defs.h"
      16  
      17  static int
      18  decode_readlink(struct tcb *tcp, int offset)
      19  {
      20  	if (entering(tcp)) {
      21  		/* pathname */
      22  		printpath(tcp, tcp->u_arg[offset]);
      23  		tprint_arg_next();
      24  	} else {
      25  		/* buf */
      26  		if (syserror(tcp))
      27  			printaddr(tcp->u_arg[offset + 1]);
      28  		else
      29  			/* Used to use printpathn(), but readlink
      30  			 * neither includes NUL in the returned count,
      31  			 * nor actually writes it into memory.
      32  			 * printpathn() would decide on printing
      33  			 * "..." continuation based on garbage
      34  			 * past return buffer's end.
      35  			 */
      36  			printstrn(tcp, tcp->u_arg[offset + 1], tcp->u_rval);
      37  		tprint_arg_next();
      38  
      39  		/* bufsiz */
      40  		PRINT_VAL_U(tcp->u_arg[offset + 2]);
      41  	}
      42  	return 0;
      43  }
      44  
      45  SYS_FUNC(readlink)
      46  {
      47  	return decode_readlink(tcp, 0);
      48  }
      49  
      50  SYS_FUNC(readlinkat)
      51  {
      52  	if (entering(tcp)) {
      53  		/* dirfd */
      54  		print_dirfd(tcp, tcp->u_arg[0]);
      55  		tprint_arg_next();
      56  	}
      57  	return decode_readlink(tcp, 1);
      58  }