/* Copyright (C) 1996-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.

   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 <assert.h>

#include <nss.h>

#include <ctype.h>

/* The following is an ugly trick to avoid a prototype declaration for

   _nss_nis_endgrent.  */

#define _nss_nis_endhostent _nss_nis_endhostent_XXX

#include <netdb.h>

#undef _nss_nis_endhostent

#include <string.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <resolv/resolv-internal.h>

#include <libc-lock.h>

#include <rpcsvc/yp.h>

#include <rpcsvc/ypclnt.h>

#include "nss-nis.h"

/* Get implementation for some internal functions. */

#include <resolv/mapv4v6addr.h>

#define ENTNAME         hostent

#define DATABASE        "hosts"

#define NEED_H_ERRNO

#define EXTRA_ARGS      , af, flags

#define EXTRA_ARGS_DECL , int af, int flags

#define ENTDATA hostent_data

struct hostent_data

  {

    unsigned char host_addr[16];	/* IPv4 or IPv6 address.  */

    char *h_addr_ptrs[2];	/* Points to that and null terminator.  */

  };

#define TRAILING_LIST_MEMBER            h_aliases

#define TRAILING_LIST_SEPARATOR_P       isspace

#include <nss/nss_files/files-parse.c>

LINE_PARSER

("#",

 {

   char *addr;

   STRING_FIELD (addr, isspace, 1);

   assert (af == AF_INET || af == AF_INET6 || af == AF_UNSPEC);

   /* Parse address.  */

   if (af != AF_INET6 && inet_pton (AF_INET, addr, entdata->host_addr) > 0)

     {

       assert ((flags & AI_V4MAPPED) == 0 || af != AF_UNSPEC);

       if (flags & AI_V4MAPPED)

	 {

	   map_v4v6_address ((char *) entdata->host_addr,

			     (char *) entdata->host_addr);

	   result->h_addrtype = AF_INET6;

	   result->h_length = IN6ADDRSZ;

	 }

       else

	 {

	   result->h_addrtype = AF_INET;

	   result->h_length = INADDRSZ;

	 }

     }

   else if (af != AF_INET

	    && inet_pton (AF_INET6, addr, entdata->host_addr) > 0)

     {

       result->h_addrtype = AF_INET6;

       result->h_length = IN6ADDRSZ;

     }

   else

     /* Illegal address: ignore line.  */

     return 0;

   /* Store a pointer to the address in the expected form.  */

   entdata->h_addr_ptrs[0] = (char *) entdata->host_addr;

   entdata->h_addr_ptrs[1] = NULL;

   result->h_addr_list = entdata->h_addr_ptrs;

   STRING_FIELD (result->h_name, isspace, 1);

 })

__libc_lock_define_initialized (static, lock)

static bool_t new_start = 1;

static char *oldkey = NULL;

static int oldkeylen = 0;

enum nss_status

_nss_nis_sethostent (int stayopen)

{

  __libc_lock_lock (lock);

  new_start = 1;

  if (oldkey != NULL)

    {

      free (oldkey);

      oldkey = NULL;

      oldkeylen = 0;

    }

  __libc_lock_unlock (lock);

  return NSS_STATUS_SUCCESS;

}

/* Make _nss_nis_endhostent an alias of _nss_nis_sethostent.  We do this

   even though the prototypes don't match.  The argument of sethostent

   is used so this makes no difference.  */

strong_alias (_nss_nis_sethostent, _nss_nis_endhostent)

/* The calling function always need to get a lock first. */

static enum nss_status

internal_nis_gethostent_r (struct hostent *host, char *buffer,

			   size_t buflen, int *errnop, int *h_errnop,

			   int af, int flags)

{

  char *domain;

  if (__glibc_unlikely (yp_get_default_domain (&domain)))

    return NSS_STATUS_UNAVAIL;

  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);

  buffer += pad;

  struct parser_data *data = (void *) buffer;

  if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))

    {

      *errnop = ERANGE;

      *h_errnop = NETDB_INTERNAL;

      return NSS_STATUS_TRYAGAIN;

    }

  buflen -= pad;

  /* Get the next entry until we found a correct one. */

  const size_t linebuflen = buffer + buflen - data->linebuffer;

  int parse_res;

  do

    {

      char *result;

      int len;

      char *outkey;

      int keylen;

      int yperr;

      if (new_start)

	yperr = yp_first (domain, "hosts.byname", &outkey, &keylen, &result,

			  &len;;

      else

	yperr = yp_next (domain, "hosts.byname", oldkey, oldkeylen, &outkey,

			 &keylen, &result, &len;;

      if (__glibc_unlikely (yperr != YPERR_SUCCESS))

	{

	  enum nss_status retval = yperr2nss (yperr);

	  switch (retval)

	    {

	    case NSS_STATUS_TRYAGAIN:

	      *errnop = errno;

	      *h_errnop = TRY_AGAIN;

	      break;

	    case NSS_STATUS_NOTFOUND:

	      *h_errnop = HOST_NOT_FOUND;

	      break;

	    default:

	      *h_errnop = NO_RECOVERY;

	      break;

	    }

	  return retval;

	}

      if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))

	{

	  free (result);

	  *h_errnop = NETDB_INTERNAL;

	  *errnop = ERANGE;

	  return NSS_STATUS_TRYAGAIN;

	}

      char *p = strncpy (data->linebuffer, result, len);

      data->linebuffer[len] = '\0';

      while (isspace (*p))

	++p;

      free (result);

      parse_res = parse_line (p, host, data, buflen, errnop, af, flags);

      if (__glibc_unlikely (parse_res == -1))

	{

	  free (outkey);

	  *h_errnop = NETDB_INTERNAL;

	  *errnop = ERANGE;

	  return NSS_STATUS_TRYAGAIN;

	}

      free (oldkey);

      oldkey = outkey;

      oldkeylen = keylen;

      new_start = 0;

    }

  while (!parse_res);

  *h_errnop = NETDB_SUCCESS;

  return NSS_STATUS_SUCCESS;

}

enum nss_status

_nss_nis_gethostent_r (struct hostent *host, char *buffer, size_t buflen,

		       int *errnop, int *h_errnop)

{

  enum nss_status status;

  __libc_lock_lock (lock);

  status = internal_nis_gethostent_r (host, buffer, buflen, errnop, h_errnop,

			(res_use_inet6 () ? AF_INET6 : AF_INET),

			(res_use_inet6 () ? AI_V4MAPPED : 0 ));

  __libc_lock_unlock (lock);

  return status;

}

static enum nss_status

internal_gethostbyname2_r (const char *name, int af, struct hostent *host,

			   char *buffer, size_t buflen, int *errnop,

			   int *h_errnop, int flags)

{

  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);

  buffer += pad;

  struct parser_data *data = (void *) buffer;

  if (name == NULL)

    {

      *errnop = EINVAL;

      return NSS_STATUS_UNAVAIL;

    }

  char *domain;

  if (yp_get_default_domain (&domain))

    return NSS_STATUS_UNAVAIL;

  if (buflen < sizeof *data + 1 + pad)

    {

      *h_errnop = NETDB_INTERNAL;

      *errnop = ERANGE;

      return NSS_STATUS_TRYAGAIN;

    }

  buflen -= pad;

  /* Convert name to lowercase.  */

  size_t namlen = strlen (name);

  /* Limit name length to the maximum size of an RPC packet.  */

  if (namlen > UDPMSGSIZE)

    {

      *errnop = ERANGE;

      return NSS_STATUS_UNAVAIL;

    }

  char name2[namlen + 1];

  size_t i;

  for (i = 0; i < namlen; ++i)

    name2[i] = tolower (name[i]);

  name2[i] = '\0';

  char *result;

  int len;

  int yperr = yp_match (domain, "hosts.byname", name2, namlen, &result, &len;;

  if (__glibc_unlikely (yperr != YPERR_SUCCESS))

    {

      enum nss_status retval = yperr2nss (yperr);

      if (retval == NSS_STATUS_TRYAGAIN)

	{

	  *h_errnop = TRY_AGAIN;

	  *errnop = errno;

	}

      if (retval == NSS_STATUS_NOTFOUND)

	*h_errnop = HOST_NOT_FOUND;

      return retval;

    }

  const size_t linebuflen = buffer + buflen - data->linebuffer;

  if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))

    {

      free (result);

      *h_errnop = NETDB_INTERNAL;

      *errnop = ERANGE;

      return NSS_STATUS_TRYAGAIN;

    }

  char *p = strncpy (data->linebuffer, result, len);

  data->linebuffer[len] = '\0';

  while (isspace (*p))

    ++p;

  free (result);

  int parse_res = parse_line (p, host, data, buflen, errnop, af, flags);

  if (__glibc_unlikely (parse_res < 1 || host->h_addrtype != af))

    {

      if (parse_res == -1)

	{

	  *h_errnop = NETDB_INTERNAL;

	  return NSS_STATUS_TRYAGAIN;

	}

      else

	{

	  *h_errnop = HOST_NOT_FOUND;

	  return NSS_STATUS_NOTFOUND;

	}

    }

  *h_errnop = NETDB_SUCCESS;

  return NSS_STATUS_SUCCESS;

}

enum nss_status

_nss_nis_gethostbyname2_r (const char *name, int af, struct hostent *host,

			   char *buffer, size_t buflen, int *errnop,

			   int *h_errnop)

{

  if (af != AF_INET && af != AF_INET6)

    {

      *h_errnop = HOST_NOT_FOUND;

      return NSS_STATUS_NOTFOUND;

    }

  return internal_gethostbyname2_r (name, af, host, buffer, buflen, errnop,

				    h_errnop,

			(res_use_inet6 () ? AI_V4MAPPED : 0));

}

enum nss_status

_nss_nis_gethostbyname_r (const char *name, struct hostent *host, char *buffer,

			  size_t buflen, int *errnop, int *h_errnop)

{

  if (res_use_inet6 ())

    {

      enum nss_status status;

      status = internal_gethostbyname2_r (name, AF_INET6, host, buffer, buflen,

					  errnop, h_errnop, AI_V4MAPPED);

      if (status == NSS_STATUS_SUCCESS)

	return status;

    }

  return internal_gethostbyname2_r (name, AF_INET, host, buffer, buflen,

				    errnop, h_errnop, 0);

}

enum nss_status

_nss_nis_gethostbyaddr_r (const void *addr, socklen_t addrlen, int af,

			  struct hostent *host, char *buffer, size_t buflen,

			  int *errnop, int *h_errnop)

{

  char *domain;

  if (__glibc_unlikely (yp_get_default_domain (&domain)))

    return NSS_STATUS_UNAVAIL;

  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);

  buffer += pad;

  struct parser_data *data = (void *) buffer;

  if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))

    {

      *errnop = ERANGE;

      *h_errnop = NETDB_INTERNAL;

      return NSS_STATUS_TRYAGAIN;

    }

  buflen -= pad;

  char *buf = inet_ntoa (*(const struct in_addr *) addr);

  char *result;

  int len;

  int yperr = yp_match (domain, "hosts.byaddr", buf, strlen (buf), &result,

			&len;;

  if (__glibc_unlikely (yperr != YPERR_SUCCESS))

    {

      enum nss_status retval = yperr2nss (yperr);

      if (retval == NSS_STATUS_TRYAGAIN)

	{

	  *h_errnop = TRY_AGAIN;

	  *errnop = errno;

	}

      else if (retval == NSS_STATUS_NOTFOUND)

	*h_errnop = HOST_NOT_FOUND;

      return retval;

    }

  const size_t linebuflen = buffer + buflen - data->linebuffer;

  if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))

    {

      free (result);

      *errnop = ERANGE;

      *h_errnop = NETDB_INTERNAL;

      return NSS_STATUS_TRYAGAIN;

    }

  char *p = strncpy (data->linebuffer, result, len);

  data->linebuffer[len] = '\0';

  while (isspace (*p))

    ++p;

  free (result);

  int parse_res = parse_line (p, host, data, buflen, errnop, af,

			      (res_use_inet6 () ? AI_V4MAPPED : 0));

  if (__glibc_unlikely (parse_res < 1))

    {

      if (parse_res == -1)

	{

	  *h_errnop = NETDB_INTERNAL;

	  return NSS_STATUS_TRYAGAIN;

	}

      else

	{

	  *h_errnop = HOST_NOT_FOUND;

	  return NSS_STATUS_NOTFOUND;

	}

    }

  *h_errnop = NETDB_SUCCESS;

  return NSS_STATUS_SUCCESS;

}

enum nss_status

_nss_nis_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,

			   char *buffer, size_t buflen, int *errnop,

			   int *herrnop, int32_t *ttlp)

{

  char *domain;

  if (yp_get_default_domain (&domain))

    {

      *herrnop = NO_DATA;

      return NSS_STATUS_UNAVAIL;

    }

  /* Convert name to lowercase.  */

  size_t namlen = strlen (name);

  /* Limit name length to the maximum size of an RPC packet.  */

  if (namlen > UDPMSGSIZE)

    {

      *errnop = ERANGE;

      return NSS_STATUS_UNAVAIL;

    }

  char name2[namlen + 1];

  size_t i;

  for (i = 0; i < namlen; ++i)

    name2[i] = tolower (name[i]);

  name2[i] = '\0';

  char *result;

  int len;

  int yperr = yp_match (domain, "hosts.byname", name2, namlen, &result, &len;;

  if (__glibc_unlikely (yperr != YPERR_SUCCESS))

    {

      enum nss_status retval = yperr2nss (yperr);

      if (retval == NSS_STATUS_TRYAGAIN)

	{

	  *herrnop = TRY_AGAIN;

	  *errnop = errno;

	}

      if (retval == NSS_STATUS_NOTFOUND)

	*herrnop = HOST_NOT_FOUND;

      return retval;

    }

  if (*pat == NULL)

    {

      uintptr_t pad = (-(uintptr_t) buffer

		       % __alignof__ (struct gaih_addrtuple));

      buffer += pad;

      buflen = buflen > pad ? buflen - pad : 0;

      if (__glibc_unlikely (buflen < sizeof (struct gaih_addrtuple)))

	{

	erange:

	  free (result);

	  *errnop = ERANGE;

	  *herrnop = NETDB_INTERNAL;

	  return NSS_STATUS_TRYAGAIN;

	}

      *pat = (struct gaih_addrtuple *) buffer;

      buffer += sizeof (struct gaih_addrtuple);

      buflen -= sizeof (struct gaih_addrtuple);

    }

  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);

  buffer += pad;

  struct parser_data *data = (void *) buffer;

  if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))

    goto erange;

  buflen -= pad;

  struct hostent host;

  int parse_res = parse_line (result, &host, data, buflen, errnop, AF_UNSPEC,

			      0);

  if (__glibc_unlikely (parse_res < 1))

    {

      if (parse_res == -1)

	{

	  *herrnop = NETDB_INTERNAL;

	  return NSS_STATUS_TRYAGAIN;

	}

      else

	{

	  *herrnop = HOST_NOT_FOUND;

	  return NSS_STATUS_NOTFOUND;

	}

    }

  (*pat)->next = NULL;

  (*pat)->family = host.h_addrtype;

  memcpy ((*pat)->addr, host.h_addr_list[0], host.h_length);

  (*pat)->scopeid = 0;

  assert (host.h_addr_list[1] == NULL);

  /* Undo the alignment for parser_data.  */

  buffer -= pad;

  buflen += pad;

  size_t h_name_len = strlen (host.h_name) + 1;

  if (h_name_len >= buflen)

    goto erange;

  (*pat)->name = memcpy (buffer, host.h_name, h_name_len);

  free (result);

  return NSS_STATUS_SUCCESS;

}