/* ttyname_r.c - A ttyname_r() replacement.

 * Copyright (C) 2003, 2004, 2012 g10 Code GmbH

 *

 * This file is part of GPGME.

 *

 * GPGME is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * GPGME is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this program; if not, see <https://gnu.org/licenses/>.

 * SPDX-License-Identifier: LGPL-2.1-or-later

 */

#if HAVE_CONFIG_H

#include <config.h>

#endif

#include <stdlib.h>

#include <errno.h>

#include <string.h>

#ifdef HAVE_UNISTD_H

# include <unistd.h>

#endif

#if !HAVE_TTYNAME_R && defined(__GNUC__)

# warning ttyname is not thread-safe, and ttyname_r is missing

#endif

/* For Android we force the use of our replacement code.  */

#if HAVE_ANDROID_SYSTEM

# undef HAVE_TTYNAME_R

#endif

int

_gpgme_ttyname_r (int fd, char *buf, size_t buflen)

{

#if HAVE_TTYNAME_R

# if HAVE_BROKEN_TTYNAME_R

   /* Solaris fails if BUFLEN is less than 128. OSF/1 5.1 completely

      ignores BUFLEN.  We use a large buffer to woraround this.  */

  {

    char largebuf[512];

    size_t namelen;

    int rc;

#  if HAVE_POSIXDECL_TTYNAME_R

    if (buflen < sizeof (largebuf))

      {

        rc = ttyname_r (fd, largebuf, (int)sizeof (largebuf));

        if (!rc)

          {

            namelen = strlen (largebuf) + 1;

            if (namelen > buflen)

              rc = ERANGE;

            else

              memcpy (buf, largebuf, namelen);

          }

      }

    else

      rc = ttyname_r (fd, buf, (int)buflen);

#  else /*!HAVE_POSIXDECL_TTYNAME_R*/

    char *name;

    if (buflen < sizeof (largebuf))

      name = ttyname_r (fd, largebuf, (int)sizeof (largebuf));

    else

      name = ttyname_r (fd, buf, (int)buflen);

    rc = name? 0 : (errno? errno : -1);

    if (!rc && buf != name)

      {

        namelen = strlen (name) + 1;

        if (namelen > buflen)

          rc = ERANGE;

        else

          memmove (buf, name, namelen);

      }

#  endif

    return rc;

  }

# else /*!HAVE_BROKEN_TTYNAME_R*/

  {

    int rc;

#  if HAVE_POSIXDECL_TTYNAME_R

    rc = ttyname_r (fd, buf, buflen);

#  else /*!HAVE_POSIXDECL_TTYNAME_R*/

    char *name;

    size_t namelen;

    name = ttyname_r (fd, buf, (int)buflen);

    rc = name? 0 : (errno? errno : -1);

    if (!rc && buf != name)

      {

        namelen = strlen (name) + 1;

        if (namelen > buflen)

          rc = ERANGE;

        else

          memmove (buf, name, namelen);

      }

#  endif

    return rc;

  }

# endif /*!HAVE_BROKEN_TTYNAME_R*/

#else /*!HAVE_TTYNAME_R*/

  char *tty;

# if HAVE_W32_SYSTEM || HAVE_ANDROID_SYSTEM

  /* We use this default one for now.  AFAICS we only need it to be

     passed to gpg and in turn to pinentry.  Providing a replacement

     is needed because elsewhere we bail out on error or Android

     provided ttyname_r prints an error message if used. */

  tty = "/dev/tty";

# else

  tty = ttyname (fd);

  if (!tty)

    return errno? errno : -1;

# endif

  strncpy (buf, tty, buflen);

  buf[buflen - 1] = '\0';

  return (strlen (tty) >= buflen) ? ERANGE : 0;

#endif /*!HAVE_TTYNAME_R*/

}