/* Prototype for the setgrent functions we use here.  */

typedef enum nss_status (*set_function) (void);

/* Prototype for the endgrent functions we use here.  */

typedef enum nss_status (*end_function) (void);

/* Prototype for the setgrent functions we use here.  */

typedef enum nss_status (*get_function) (struct group *, char *,

					 size_t, int *);

static enum nss_status

compat_call (service_user *nip, const char *user, gid_t group, long int *start,

	     long int *size, gid_t **groupsp, long int limit, int *errnop)

{

  struct group grpbuf;

  enum nss_status status;

  set_function setgrent_fct;

  get_function getgrent_fct;

  end_function endgrent_fct;

  gid_t *groups = *groupsp;

  getgrent_fct = __nss_lookup_function (nip, "getgrent_r");

  if (getgrent_fct == NULL)

    return NSS_STATUS_UNAVAIL;

  setgrent_fct = __nss_lookup_function (nip, "setgrent");

  if (setgrent_fct)

    {

      status = DL_CALL_FCT (setgrent_fct, ());

      if (status != NSS_STATUS_SUCCESS)

	return status;

    }

  endgrent_fct = __nss_lookup_function (nip, "endgrent");

  struct scratch_buffer tmpbuf;

  scratch_buffer_init (&tmpbuf);

  enum nss_status result = NSS_STATUS_SUCCESS;

  do

    {

      while ((status = DL_CALL_FCT (getgrent_fct,

				     (&grpbuf, tmpbuf.data, tmpbuf.length,

				      errnop)),

	      status == NSS_STATUS_TRYAGAIN)

	     && *errnop == ERANGE)

        {

	  if (!scratch_buffer_grow (&tmpbuf))

	    {

	      result = NSS_STATUS_TRYAGAIN;

	      goto done;

	    }

        }

      if (status != NSS_STATUS_SUCCESS)

        goto done;

      if (grpbuf.gr_gid != group)

        {

          char **m;

          for (m = grpbuf.gr_mem; *m != NULL; ++m)

            if (strcmp (*m, user) == 0)

              {

		/* Check whether the group is already on the list.  */

		long int cnt;

		for (cnt = 0; cnt < *start; ++cnt)

		  if (groups[cnt] == grpbuf.gr_gid)

		    break;

		if (cnt == *start)

		  {

		    /* Matches user and not yet on the list.  Insert

		       this group.  */

		    if (__glibc_unlikely (*start == *size))

		      {

			/* Need a bigger buffer.  */

			gid_t *newgroups;

			long int newsize;

			if (limit > 0 && *size == limit)

			  /* We reached the maximum.  */

			  goto done;

			if (limit <= 0)

			  newsize = 2 * *size;

			else

			  newsize = MIN (limit, 2 * *size);

			newgroups = realloc (groups,

					     newsize * sizeof (*groups));

			if (newgroups == NULL)

			  goto done;

			*groupsp = groups = newgroups;

			*size = newsize;

		      }

		    groups[*start] = grpbuf.gr_gid;

		    *start += 1;

		  }

                break;

              }

        }

    }

  while (status == NSS_STATUS_SUCCESS);

 done:

  scratch_buffer_free (&tmpbuf);

  if (endgrent_fct)

    DL_CALL_FCT (endgrent_fct, ());

  return result;

}