/*

 * Copyright (C) 2013 Martin Willi

 *

 * Copyright (C) secunet Security Networks AG

 *

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

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2 of the License, or (at your

 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.

 *

 * This program 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 General Public License

 * for more details.

 */

#include <library.h>

#include <networking/streams/stream_unix.h>

#include <errno.h>

#include <unistd.h>

#include <sys/socket.h>

#include <sys/un.h>

#include <sys/stat.h>

/**

 * See header

 */

stream_service_t *stream_service_create_unix(char *uri, int backlog)

{

  struct sockaddr_un addr;

  mode_t old;

  int fd, len;

  len = stream_parse_uri_unix(uri, &addr);

  if (len == -1)

  {

    DBG1(DBG_NET, "invalid stream URI: '%s'", uri);

    return NULL;

  }

  if (!lib->caps->check(lib->caps, CAP_CHOWN))

  { /* required to chown(2) service socket */

    DBG1(DBG_NET, "cannot change ownership of socket '%s' without "

       "CAP_CHOWN capability. socket directory should be accessible to "

       "UID/GID under which the daemon will run", uri);

  }

  fd = socket(AF_UNIX, SOCK_STREAM, 0);

  if (fd == -1)

  {

    DBG1(DBG_NET, "opening socket '%s' failed: %s", uri, strerror(errno));

    return NULL;

  }

  unlink(addr.sun_path);

  old = umask(S_IRWXO);

  if (bind(fd, (struct sockaddr*)&addr, len) < 0)

  {

    DBG1(DBG_NET, "binding socket '%s' failed: %s", uri, strerror(errno));

    close(fd);

    return NULL;

  }

  umask(old);

  /* Only attempt to change owner of socket if we have CAP_CHOWN. Otherwise,

   * attempt to change group of socket to group under which charon runs after

   * dropping caps. This requires the user that charon starts as to:

   * a) Have write access to the socket dir.

   * b) Belong to the group that charon will run under after dropping caps. */

  if (lib->caps->check(lib->caps, CAP_CHOWN))

  {

    if (chown(addr.sun_path, lib->caps->get_uid(lib->caps),

          lib->caps->get_gid(lib->caps)) != 0)

    {

      DBG1(DBG_NET, "changing socket owner/group for '%s' failed: %s",

         uri, strerror(errno));

    }

  }

  else

  {

    if (chown(addr.sun_path, -1, lib->caps->get_gid(lib->caps)) != 0)

    {

      DBG1(DBG_NET, "changing socket group for '%s' failed: %s",

         uri, strerror(errno));

    }

  }

  if (listen(fd, backlog) < 0)

  {

    DBG1(DBG_NET, "listen on socket '%s' failed: %s", uri, strerror(errno));

    unlink(addr.sun_path);

    close(fd);

    return NULL;

  }

  return stream_service_create_from_fd(fd);

}