/* Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library 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.

   The GNU C Library 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 the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <netdb.h>

#include "nsswitch.h"

#include <resolv/resolv_context.h>

/* Set up NIP to run through the services.  If ALL is zero, use NIP's

   current location if it's not nil.  Return nonzero if there are no

   services (left).  */

static int

setup (const char *func_name, db_lookup_function lookup_fct,

       void **fctp, service_user **nip, service_user **startp, int all)

{

  int no_more;

  if (*startp == NULL)

    {

      no_more = lookup_fct (nip, func_name, NULL, fctp);

      *startp = no_more ? (service_user *) -1l : *nip;

    }

  else if (*startp == (service_user *) -1l)

    /* No services at all.  */

    return 1;

  else

    {

      if (all || !*nip)

	/* Reset to the beginning of the service list.  */

	*nip = *startp;

      /* Look up the first function.  */

      no_more = __nss_lookup (nip, func_name, NULL, fctp);

    }

  return no_more;

}

void

__nss_setent (const char *func_name, db_lookup_function lookup_fct,

	      service_user **nip, service_user **startp,

	      service_user **last_nip, int stayopen, int *stayopen_tmp,

	      int res)

{

  union

  {

    setent_function f;

    void *ptr;

  } fct;

  int no_more;

  struct resolv_context *res_ctx = NULL;

  if (res)

    {

      res_ctx = __resolv_context_get ();

      if (res_ctx == NULL)

	{

	  __set_h_errno (NETDB_INTERNAL);

	  return;

	}

    }

  /* Cycle through the services and run their `setXXent' functions until

     we find an available service.  */

  no_more = setup (func_name, lookup_fct, &fct.ptr, nip,

		   startp, 1);

  while (! no_more)

    {

      int is_last_nip = *nip == *last_nip;

      enum nss_status status;

      if (stayopen_tmp)

	status = DL_CALL_FCT (fct.f, (*stayopen_tmp));

      else

	status = DL_CALL_FCT (fct.f, (0));

      /* This is a special-case.  When [SUCCESS=merge] is in play,

         _nss_next2() will skip to the next database.  Due to the

         implementation of that function, we can't know whether we're

         in an enumeration or an individual lookup, which behaves

         differently with regards to merging.  We'll treat SUCCESS as

         an indication to start the enumeration at this database. */

      if (nss_next_action (*nip, status) == NSS_ACTION_MERGE)

	no_more = 1;

      else

	no_more = __nss_next2 (nip, func_name, NULL, &fct.ptr, status, 0);

      if (is_last_nip)

	*last_nip = *nip;

    }

  __resolv_context_put (res_ctx);

  if (stayopen_tmp)

    *stayopen_tmp = stayopen;

}

void

__nss_endent (const char *func_name, db_lookup_function lookup_fct,

	      service_user **nip, service_user **startp,

	      service_user **last_nip, int res)

{

  union

  {

    endent_function f;

    void *ptr;

  } fct;

  int no_more;

  struct resolv_context *res_ctx = NULL;

  if (res)

    {

      res_ctx = __resolv_context_get ();

      if (res_ctx == NULL)

	{

	  __set_h_errno (NETDB_INTERNAL);

	  return;

	}

    }

  /* Cycle through all the services and run their endXXent functions.  */

  no_more = setup (func_name, lookup_fct, &fct.ptr, nip, startp, 1);

  while (! no_more)

    {

      /* Ignore status, we force check in __NSS_NEXT.  */

      DL_CALL_FCT (fct.f, ());

      if (*nip == *last_nip)

	/* We have processed all services which were used.  */

	break;

      no_more = __nss_next2 (nip, func_name, NULL, &fct.ptr, 0, 1);

    }

  *last_nip = *nip = NULL;

  __resolv_context_put (res_ctx);

}

int

__nss_getent_r (const char *getent_func_name,

		const char *setent_func_name,

		db_lookup_function lookup_fct,

		service_user **nip, service_user **startp,

		service_user **last_nip, int *stayopen_tmp, int res,

		void *resbuf, char *buffer, size_t buflen,

		void **result, int *h_errnop)

{

  union

  {

    getent_function f;

    void *ptr;

  } fct;

  int no_more;

  enum nss_status status;

  struct resolv_context *res_ctx = NULL;

  if (res)

    {

      res_ctx = __resolv_context_get ();

      if (res_ctx == NULL)

	{

	  *h_errnop = NETDB_INTERNAL;

	  *result = NULL;

	  return errno;

	}

    }

  /* Initialize status to return if no more functions are found.  */

  status = NSS_STATUS_NOTFOUND;

  /* Run through available functions, starting with the same function last

     run.  We will repeat each function as long as it succeeds, and then go

     on to the next service action.  */

  no_more = setup (getent_func_name, lookup_fct, &fct.ptr, nip,

		   startp, 0);

  while (! no_more)

    {

      int is_last_nip = *nip == *last_nip;

      status = DL_CALL_FCT (fct.f,

			    (resbuf, buffer, buflen, &errno, &h_errno));

      /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the

	 provided buffer is too small.  In this case we should give

	 the user the possibility to enlarge the buffer and we should

	 not simply go on with the next service (even if the TRYAGAIN

	 action tells us so).  */

      if (status == NSS_STATUS_TRYAGAIN

	  && (h_errnop == NULL || *h_errnop == NETDB_INTERNAL)

	  && errno == ERANGE)

	break;

      do

	{

        /* This is a special-case.  When [SUCCESS=merge] is in play,

           _nss_next2() will skip to the next database.  Due to the

           implementation of that function, we can't know whether we're

           in an enumeration or an individual lookup, which behaves

           differently with regards to merging.  We'll treat SUCCESS as

           an indication to return the results here. */

	  if (status == NSS_STATUS_SUCCESS

	      && nss_next_action (*nip, status) == NSS_ACTION_MERGE)

	    no_more = 1;

	  else

	    no_more = __nss_next2 (nip, getent_func_name, NULL, &fct.ptr,

				   status, 0);

	  if (is_last_nip)

	    *last_nip = *nip;

	  if (! no_more)

	    {

	      /* Call the `setXXent' function.  This wasn't done before.  */

	      union

	      {

		setent_function f;

		void *ptr;

	      } sfct;

	      no_more = __nss_lookup (nip, setent_func_name, NULL, &sfct.ptr);

	      if (! no_more)

	        {

		  if (stayopen_tmp)

		    status = DL_CALL_FCT (sfct.f, (*stayopen_tmp));

		  else

		    status = DL_CALL_FCT (sfct.f, (0));

		}

	      else

		status = NSS_STATUS_NOTFOUND;

	    }

	}

      while (! no_more && status != NSS_STATUS_SUCCESS);

    }

  __resolv_context_put (res_ctx);

  *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;

  return (status == NSS_STATUS_SUCCESS ? 0

	  : status != NSS_STATUS_TRYAGAIN ? ENOENT

	  /* h_errno functions only set errno if h_errno is NETDB_INTERNAL.  */

	  : (h_errnop == NULL || *h_errnop == NETDB_INTERNAL) ? errno

	  : EAGAIN);

}