glibc/nis/nss_compat/compat-pwd.c

/* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <nss.h>
#include <pwd.h>
#include <errno.h>
#include <ctype.h>
#include <netdb.h>
#include <string.h>
#include <libc-lock.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>
#include <rpcsvc/nis.h>
#include <rpcsvc/nislib.h>
#include <nsswitch.h>

#include "netgroup.h"
#include "nss-nisplus.h"

static service_user *ni = NULL;
static bool_t use_nisplus = FALSE; /* default: passwd_compat: nis */

/* Get the declaration of the parser function.  */
#define ENTNAME pwent
#define STRUCTURE passwd
#define EXTERN_PARSER
#include "../../nss/nss_files/files-parse.c"

/* Structure for remembering -@netgroup and -user members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
  {
    char *data;
    int current;
    int size;
  };

struct ent_t
  {
    bool_t netgroup;
    bool_t nis;
    bool_t first;
    char *oldkey;
    int oldkeylen;
    nis_result *result;
    nis_name *names;
    u_long names_nr;
    FILE *stream;
    struct blacklist_t blacklist;
    struct passwd pwd;
    struct __netgrent netgrdata;
  };
typedef struct ent_t ent_t;

static ent_t ext_ent = {0, 0, 0, NULL, 0, NULL, NULL, 0, NULL, {NULL, 0, 0},
			{NULL, NULL, 0, 0, NULL, NULL, NULL}};

/* Protect global state against multiple changers.  */
__libc_lock_define_initialized (static, lock)

/* Prototypes for local functions.  */
static void blacklist_store_name (const char *, ent_t *);
static int in_blacklist (const char *, int, ent_t *);
extern int _nss_nisplus_parse_pwent (nis_result *, struct passwd *,
				     char *, size_t);
static void
give_pwd_free (struct passwd *pwd)
{
  if (pwd->pw_name != NULL)
    free (pwd->pw_name);
  if (pwd->pw_passwd != NULL)
    free (pwd->pw_passwd);
  if (pwd->pw_gecos != NULL)
    free (pwd->pw_gecos);
  if (pwd->pw_dir != NULL)
    free (pwd->pw_dir);
  if (pwd->pw_shell != NULL)
    free (pwd->pw_shell);

  memset (pwd, '\0', sizeof (struct passwd));
}

static size_t
pwd_need_buflen (struct passwd *pwd)
{
  size_t len = 0;

  if (pwd->pw_passwd != NULL)
    len += strlen (pwd->pw_passwd) + 1;

  if (pwd->pw_gecos != NULL)
    len += strlen (pwd->pw_gecos) + 1;

  if (pwd->pw_dir != NULL)
    len += strlen (pwd->pw_dir) + 1;

  if (pwd->pw_shell != NULL)
    len += strlen (pwd->pw_shell) + 1;

  return len;
}

static void
copy_pwd_changes (struct passwd *dest, struct passwd *src,
		  char *buffer, size_t buflen)
{
  if (src->pw_passwd != NULL && strlen (src->pw_passwd))
    {
      if (buffer == NULL)
	dest->pw_passwd = strdup (src->pw_passwd);
      else if (dest->pw_passwd &&
	       strlen (dest->pw_passwd) >= strlen (src->pw_passwd))
	strcpy (dest->pw_passwd, src->pw_passwd);
      else
	{
	  dest->pw_passwd = buffer;
	  strcpy (dest->pw_passwd, src->pw_passwd);
	  buffer += strlen (dest->pw_passwd) + 1;
	  buflen = buflen - (strlen (dest->pw_passwd) + 1);
	}
    }

  if (src->pw_gecos != NULL && strlen (src->pw_gecos))
    {
      if (buffer == NULL)
	dest->pw_gecos = strdup (src->pw_gecos);
      else if (dest->pw_gecos &&
	       strlen (dest->pw_gecos) >= strlen (src->pw_gecos))
	strcpy (dest->pw_gecos, src->pw_gecos);
      else
	{
	  dest->pw_gecos = buffer;
	  strcpy (dest->pw_gecos, src->pw_gecos);
	  buffer += strlen (dest->pw_gecos) + 1;
	  buflen = buflen - (strlen (dest->pw_gecos) + 1);
	}
    }
  if (src->pw_dir != NULL && strlen (src->pw_dir))
    {
      if (buffer == NULL)
	dest->pw_dir = strdup (src->pw_dir);
      else if (dest->pw_dir &&
	       strlen (dest->pw_dir) >= strlen (src->pw_dir))
	strcpy (dest->pw_dir, src->pw_dir);
      else
	{
	  dest->pw_dir = buffer;
	  strcpy (dest->pw_dir, src->pw_dir);
	  buffer += strlen (dest->pw_dir) + 1;
	  buflen = buflen - (strlen (dest->pw_dir) + 1);
	}
    }

  if (src->pw_shell != NULL && strlen (src->pw_shell))
    {
      if (buffer == NULL)
	dest->pw_shell = strdup (src->pw_shell);
      else if (dest->pw_shell &&
	       strlen (dest->pw_shell) >= strlen (src->pw_shell))
	strcpy (dest->pw_shell, src->pw_shell);
      else
	{
	  dest->pw_shell = buffer;
	  strcpy (dest->pw_shell, src->pw_shell);
	  buffer += strlen (dest->pw_shell) + 1;
	  buflen = buflen - (strlen (dest->pw_shell) + 1);
	}
    }
}

static enum nss_status
internal_setpwent (ent_t *ent)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  ent->nis = ent->first = ent->netgroup = 0;

  /* If something was left over free it.  */
  if (ent->netgroup)
    __internal_endnetgrent (&ent->netgrdata);

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  if (ent->result != NULL)
    {
      nis_freeresult (ent->result);
      ent->result = NULL;
    }

  if (ent->names != NULL)
    {
      nis_freenames (ent->names);
      ent->names = NULL;
    }
  ent->names_nr = 0;
  ent->blacklist.current = 0;
  if (ent->blacklist.data != NULL)
    ent->blacklist.data[0] = '\0';

  if (ent->stream == NULL)
    {
      ent->stream = fopen ("/etc/passwd", "r");

      if (ent->stream == NULL)
	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
    }
  else
    rewind (ent->stream);

  give_pwd_free (&ent->pwd);

  return status;
}


enum nss_status
_nss_compat_setpwent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  if (ni == NULL)
    {
      __nss_database_lookup ("passwd_compat", NULL, "nis", &ni);
      use_nisplus = (strcmp (ni->name, "nisplus") == 0);
    }

  result = internal_setpwent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}


static enum nss_status
internal_endpwent (ent_t *ent)
{
  if (ent->stream != NULL)
    {
      fclose (ent->stream);
      ent->stream = NULL;
    }

  ent->nis = ent->first = ent->netgroup = 0;

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  if (ent->result != NULL)
    {
      nis_freeresult (ent->result);
      ent->result = NULL;
    }

  if (ent->names != NULL)
    {
      nis_freenames (ent->names);
      ent->names = NULL;
    }
  ent->names_nr = 0;

  ent->blacklist.current = 0;
  if (ent->blacklist.data != NULL)
    ent->blacklist.data[0] = '\0';

  give_pwd_free (&ent->pwd);

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_endpwent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  if (ext_ent.netgroup)
    __internal_endnetgrent (&ext_ent.netgrdata);

  result = internal_endpwent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}

static enum nss_status
getpwent_next_nis_netgr (struct passwd *result, ent_t *ent, char *group,
			 char *buffer, size_t buflen)
{
  struct parser_data *data = (void *) buffer;
  char *ypdomain, *host, *user, *domain, *outval, *p, *p2;
  int status, outvallen;
  size_t p2len;
  
  if (yp_get_default_domain (&ypdomain) != YPERR_SUCCESS)
    {
      ent->netgroup = 0;
      ent->first = 0;
      give_pwd_free (&ent->pwd);
      return NSS_STATUS_UNAVAIL;
    }

  if (ent->first == TRUE)
    {
      bzero (&ent->netgrdata, sizeof (struct __netgrent));
      __internal_setnetgrent (group, &ent->netgrdata);
      ent->first = FALSE;
    }

  while (1)
    {
      status = __internal_getnetgrent_r (&host, &user, &domain,
					 &ent->netgrdata, buffer, buflen);
      if (status != 1)
	{
	  __internal_endnetgrent (&ent->netgrdata);
	  ent->netgroup = 0;
	  give_pwd_free (&ent->pwd);
	  return NSS_STATUS_RETURN;
	}

      if (user == NULL || user[0] == '-')
	continue;

      if (domain != NULL && strcmp (ypdomain, domain) != 0)
	continue;

      if (yp_match (ypdomain, "passwd.byname", user,
		    strlen (user), &outval, &outvallen)
	  != YPERR_SUCCESS)
	continue;

      p2len = pwd_need_buflen (&ent->pwd);
      if (p2len > buflen)
	{
	  __set_errno (ERANGE);
	  return NSS_STATUS_TRYAGAIN;
	}
      p2 = buffer + (buflen - p2len);
      buflen -= p2len;
      p = strncpy (buffer, outval, buflen);
      while (isspace (*p))
	p++;
      free (outval);
      if (_nss_files_parse_pwent (p, result, data, buflen))
	{
	  copy_pwd_changes (result, &ent->pwd, p2, p2len);
	  break;
	}
    }

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getpwent_next_nisplus_netgr (struct passwd *result, ent_t *ent, char *group,
			     char *buffer, size_t buflen)
{
  char *ypdomain, *host, *user, *domain, *p2;
  int status, parse_res;
  size_t p2len;
  nis_result *nisres;
  
  /* Maybe we should use domainname here ? We need the current 
     domainname for the domain field in netgroups */
  if (yp_get_default_domain (&ypdomain) != YPERR_SUCCESS)
    {
      ent->netgroup = 0;
      ent->first = 0;
      give_pwd_free (&ent->pwd);
      return NSS_STATUS_UNAVAIL;
    }

  if (ent->first == TRUE)
    {
      bzero (&ent->netgrdata, sizeof (struct __netgrent));
      __internal_setnetgrent (group, &ent->netgrdata);
      ent->first = FALSE;
    }

  while (1)
    {
      status = __internal_getnetgrent_r (&host, &user, &domain,
					 &ent->netgrdata, buffer, buflen);
      if (status != 1)
	{
	  __internal_endnetgrent (&ent->netgrdata);
	  ent->netgroup = 0;
	  give_pwd_free (&ent->pwd);
	  return NSS_STATUS_RETURN;
	}

      if (user == NULL || user[0] == '-')
	continue;

      if (domain != NULL && strcmp (ypdomain, domain) != 0)
	continue;

      p2len = pwd_need_buflen (&ent->pwd);
      if (p2len > buflen)
	{
	  __set_errno (ERANGE);
	  return NSS_STATUS_TRYAGAIN;
	}
      p2 = buffer + (buflen - p2len);
      buflen -= p2len;
      {      
	char buf[strlen (user) + 30];
	sprintf(buf, "[name=%s],passwd.org_dir", user);
	nisres = nis_list(buf, EXPAND_NAME, NULL, NULL);
      }
      if (niserr2nss (nisres->status) != NSS_STATUS_SUCCESS)
	{
	  nis_freeresult (nisres);
	  continue;
	}
      parse_res = _nss_nisplus_parse_pwent (nisres, result, buffer, buflen);
      nis_freeresult (nisres);
      
      if (parse_res)
	{
	  copy_pwd_changes (result, &ent->pwd, p2, p2len);
	  break;
	}
    }

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getpwent_next_netgr (struct passwd *result, ent_t *ent, char *group,
		     char *buffer, size_t buflen)
{
  if (use_nisplus)
    return getpwent_next_nisplus_netgr (result, ent, group, buffer, buflen);
  else
    return getpwent_next_nis_netgr (result, ent, group, buffer, buflen);
}

static enum nss_status
getpwent_next_nisplus (struct passwd *result, ent_t *ent, char *buffer,
		       size_t buflen)
{
  int parse_res;
  size_t p2len;
  char *p2;

  if (ent->names == NULL)
    {
      ent->names = nis_getnames ("passwd.org_dir");
      if (ent->names == NULL || ent->names[0] == NULL)
	{
	  ent->nis = 0;
	  return NSS_STATUS_UNAVAIL;
	}
    }
  
  p2len = pwd_need_buflen (&ent->pwd);
  if (p2len > buflen)
    {
      __set_errno (ERANGE);
      return NSS_STATUS_TRYAGAIN;
    }
  p2 = buffer + (buflen - p2len);
  buflen -= p2len;
  do
    {
      if (ent->first)
	{
	next_name:
	  ent->result = nis_first_entry(ent->names[ent->names_nr]);
          if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
	    {
	      ent->nis = 0;
	      give_pwd_free (&ent->pwd);
	      return niserr2nss (ent->result->status);
	    }
	  ent->first = FALSE;
	}
      else
	{
	  nis_result *res;
	  
	  res = nis_next_entry(ent->names[ent->names_nr], 
			       &ent->result->cookie);
	  nis_freeresult (ent->result);
	  ent->result = res;
	  if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
	    {
	      if ((ent->result->status == NIS_NOTFOUND) &&
		  ent->names[ent->names_nr + 1] != NULL)
		{
		  nis_freeresult (ent->result);
		  ent->names_nr += 1;
		  goto next_name;
		}
	      else
		{
		  ent->nis = 0;
		  give_pwd_free (&ent->pwd);
		  return niserr2nss (ent->result->status);
		}
	    }
	}
      parse_res = _nss_nisplus_parse_pwent (ent->result, result, buffer, 
					    buflen);
      if (parse_res && 
	  in_blacklist (result->pw_name, strlen (result->pw_name), ent))
	parse_res = 0; /* if result->pw_name in blacklist,search next entry */
    }
  while (!parse_res);
  
  copy_pwd_changes (result, &ent->pwd, p2, p2len);
  
  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getpwent_next_nis (struct passwd *result, ent_t *ent, char *buffer,
		   size_t buflen)
{
  struct parser_data *data = (void *) buffer;
  char *domain, *outkey, *outval, *p, *p2;
  int outkeylen, outvallen, parse_res;
  size_t p2len;

  if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
    {
      ent->nis = 0;
      give_pwd_free (&ent->pwd);
      return NSS_STATUS_UNAVAIL;
    }

  p2len = pwd_need_buflen (&ent->pwd);
  if (p2len > buflen)
    {
      __set_errno (ERANGE);
      return NSS_STATUS_TRYAGAIN;
    }
  p2 = buffer + (buflen - p2len);
  buflen -= p2len;
  do
    {
      if (ent->first)
	{
	  if (yp_first (domain, "passwd.byname", &outkey, &outkeylen,
			&outval, &outvallen) != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      give_pwd_free (&ent->pwd);
	      return NSS_STATUS_UNAVAIL;
	    }

	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	  ent->first = FALSE;
	}
      else
	{
	  if (yp_next (domain, "passwd.byname", ent->oldkey, ent->oldkeylen,
		       &outkey, &outkeylen, &outval, &outvallen)
	      != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      give_pwd_free (&ent->pwd);
	      return NSS_STATUS_NOTFOUND;
	    }

	  free (ent->oldkey);
	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	}

      /* Copy the found data to our buffer  */
      p = strncpy (buffer, outval, buflen);

      /* ...and free the data.  */
      free (outval);

      while (isspace (*p))
	++p;
      parse_res = _nss_files_parse_pwent (p, result, data, buflen);
      if (parse_res &&
	  in_blacklist (result->pw_name, strlen (result->pw_name), ent))
	parse_res = 0;
    }
  while (!parse_res);

  copy_pwd_changes (result, &ent->pwd, p2, p2len);

  return NSS_STATUS_SUCCESS;
}

/* This function handle the +user entrys in /etc/passwd */
static enum nss_status
getpwent_next_file_plususer (struct passwd *result, char *buffer, 
			     size_t buflen)
{
  struct parser_data *data = (void *) buffer;
  struct passwd pwd;
  int parse_res;
  char *p;
  size_t plen;
  
  memset (&pwd, '\0', sizeof (struct passwd));
  
  copy_pwd_changes (&pwd, result, NULL, 0);
  
  plen = pwd_need_buflen (&pwd);
  if (plen > buflen)
    {
      __set_errno (ERANGE);
      return NSS_STATUS_TRYAGAIN;
    }
  p = buffer + (buflen - plen);
  buflen -= plen;
  
  if (use_nisplus) /* Do the NIS+ query here */
    {
      nis_result *res;
      char buf[strlen (result->pw_name) + 24];
      
      sprintf(buf, "[name=%s],passwd.org_dir",
	      &result->pw_name[1]);
      res = nis_list(buf, EXPAND_NAME, NULL, NULL);
      if (niserr2nss (res->status) != NSS_STATUS_SUCCESS)
	{
	  enum nss_status status =  niserr2nss (res->status);
	  
	  nis_freeresult (res);
	  return status;
	}
      parse_res = _nss_nisplus_parse_pwent (res, result, buffer, buflen);
      nis_freeresult (res);
    }
  else /* Use NIS */
    {
      char *domain;
      char *outval;
      int outvallen;
      
      if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
	return NSS_STATUS_TRYAGAIN;
      
      if (yp_match (domain, "passwd.byname", &result->pw_name[1],
		    strlen (result->pw_name) - 1, &outval, &outvallen)
	  != YPERR_SUCCESS)
	return NSS_STATUS_TRYAGAIN;
      p = strncpy (buffer, outval, 
		   buflen < outvallen ? buflen : outvallen);
      free (outval);
      while (isspace (*p))
	p++;
      parse_res = _nss_files_parse_pwent (p, result, data, buflen);
    }
  
  if (parse_res)
    {
      copy_pwd_changes (result, &pwd, p, plen);
      give_pwd_free (&pwd);
      /* We found the entry.  */
      return NSS_STATUS_SUCCESS;
    }
  else
    {
      /* Give buffer the old len back */
      buflen += plen;
      give_pwd_free (&pwd);
    }
  return NSS_STATUS_RETURN;
}

static enum nss_status
getpwent_next_file (struct passwd *result, ent_t *ent,
		    char *buffer, size_t buflen)
{
  struct parser_data *data = (void *) buffer;
  while (1)
    {
      char *p;

      do
	{
	  p = fgets (buffer, buflen, ent->stream);
	  if (p == NULL)
	    return NSS_STATUS_NOTFOUND;

	  /* Terminate the line for any case.  */
	  buffer[buflen - 1] = '\0';

	  /* Skip leading blanks.  */
	  while (isspace (*p))
	    ++p;
	}
      while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines.  */
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !_nss_files_parse_pwent (p, result, data, buflen));

      if (result->pw_name[0] != '+' && result->pw_name[0] != '-')
	/* This is a real entry.  */
	break;

      /* -@netgroup */
      if (result->pw_name[0] == '-' && result->pw_name[1] == '@'
	  && result->pw_name[2] != '\0')
	{
	  char *user, *host, *domain;

	  setnetgrent (&result->pw_name[2]);
	  while (getnetgrent (&host, &user, &domain))
	    {
	      if (user != NULL && user[0] != '-')
		blacklist_store_name (user, ent);
	    }
	  endnetgrent ();
	  continue;
	}

      /* +@netgroup */
      if (result->pw_name[0] == '+' && result->pw_name[1] == '@'
	  && result->pw_name[2] != '\0')
	{
	  int status;

	  ent->netgroup = TRUE;
	  ent->first = TRUE;
	  copy_pwd_changes (&ent->pwd, result, NULL, 0);

	  status = getpwent_next_netgr (result, ent, &result->pw_name[2],
					buffer, buflen);
	  if (status == NSS_STATUS_RETURN)
	    continue;
	  else
	    return status;
	}

      /* -user */
      if (result->pw_name[0] == '-' && result->pw_name[1] != '\0'
	  && result->pw_name[1] != '@')
	{
	  blacklist_store_name (&result->pw_name[1], ent);
	  continue;
	}

      /* +user */
      if (result->pw_name[0] == '+' && result->pw_name[1] != '\0'
	  && result->pw_name[1] != '@')
	{
	  enum nss_status status;
	
	  status = getpwent_next_file_plususer (result, buffer, buflen);
	  if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
	    break;
	  else
	    if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
	      continue;
	    else
	      return status;
	}

      /* +:... */
      if (result->pw_name[0] == '+' && result->pw_name[1] == '\0')
	{
	  ent->nis = TRUE;
	  ent->first = TRUE;
	  copy_pwd_changes (&ent->pwd, result, NULL, 0);

	  if (use_nisplus)
	    return getpwent_next_nisplus (result, ent, buffer, buflen);
	  else
	    return getpwent_next_nis (result, ent, buffer, buflen);
	}
    }

  return NSS_STATUS_SUCCESS;
}


static enum nss_status
internal_getpwent_r (struct passwd *pw, ent_t *ent, char *buffer,
		     size_t buflen)
{
  if (ent->netgroup)
    {
      int status;

      /* We are searching members in a netgroup */
      /* Since this is not the first call, we don't need the group name */
      status = getpwent_next_netgr (pw, ent, NULL, buffer, buflen);
      if (status == NSS_STATUS_RETURN)
	return getpwent_next_file (pw, ent, buffer, buflen);
      else
	return status;
    }
  else if (ent->nis)
    {
      if (use_nisplus)
	return getpwent_next_nisplus (pw, ent, buffer, buflen);
      else
	return getpwent_next_nis (pw, ent, buffer, buflen);
    }
  else
    return getpwent_next_file (pw, ent, buffer, buflen);
}

enum nss_status
_nss_compat_getpwent_r (struct passwd *pwd, char *buffer,
			size_t buflen)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  __libc_lock_lock (lock);

  if (ni == NULL)
    {
      __nss_database_lookup ("passwd_compat", NULL, "nis", &ni);
      use_nisplus = (strcmp (ni->name, "nisplus") == 0);
    }

  /* Be prepared that the setpwent function was not called before.  */
  if (ext_ent.stream == NULL)
    status = internal_setpwent (&ext_ent);

  if (status == NSS_STATUS_SUCCESS)
    status = internal_getpwent_r (pwd, &ext_ent, buffer, buflen);

  __libc_lock_unlock (lock);

  return status;
}


enum nss_status
_nss_compat_getpwnam_r (const char *name, struct passwd *pwd,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, 0, NULL, 0, NULL, NULL, 0, NULL, {NULL, 0, 0},
	       {NULL, NULL, 0, 0, NULL, NULL, NULL}};
  enum nss_status status;

  if (name[0] == '-' || name[0] == '+')
    return NSS_STATUS_NOTFOUND;

  __libc_lock_lock (lock);

  if (ni == NULL)
    {
      __nss_database_lookup ("passwd_compat", NULL, "nis", &ni);
      use_nisplus = (strcmp (ni->name, "nisplus") == 0);
    }
  
  __libc_lock_unlock (lock);

  status = internal_setpwent (&ent);
  if (status != NSS_STATUS_SUCCESS)
    return status;

  while ((status = internal_getpwent_r (pwd, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (strcmp (pwd->pw_name, name) == 0)
      break;

  internal_endpwent (&ent);
  return status;
}


enum nss_status
_nss_compat_getpwuid_r (uid_t uid, struct passwd *pwd,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, 0, NULL, 0, NULL, NULL, 0, NULL, {NULL, 0, 0},
	       {NULL, NULL, 0, 0, NULL, NULL, NULL}};
  enum nss_status status;
  
  __libc_lock_lock (lock);
  
  if (ni == NULL)
    {
      __nss_database_lookup ("passwd_compat", NULL, "nis", &ni);
      use_nisplus = (strcmp (ni->name, "nisplus") == 0);
    }
  
  __libc_lock_unlock (lock);
  
  status = internal_setpwent (&ent);
  if (status != NSS_STATUS_SUCCESS)
    return status;

  while ((status = internal_getpwent_r (pwd, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (pwd->pw_uid == uid && pwd->pw_name[0] != '+' && pwd->pw_name[0] != '-')
      break;

  internal_endpwent (&ent);
  return status;
}


/* Support routines for remembering -@netgroup and -user entries.
   The names are stored in a single string with `|' as separator. */
static void
blacklist_store_name (const char *name, ent_t *ent)
{
  int namelen = strlen (name);
  char *tmp;

  /* first call, setup cache */
  if (ent->blacklist.size == 0)
    {
      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
      ent->blacklist.data = malloc (ent->blacklist.size);
      if (ent->blacklist.data == NULL)
	return;
      ent->blacklist.data[0] = '|';
      ent->blacklist.data[1] = '\0';
      ent->blacklist.current = 1;
    }
  else
    {
      if (in_blacklist (name, namelen, ent))
	return;			/* no duplicates */

      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
	{
	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
	  if (tmp == NULL)
	    {
	      free (ent->blacklist.data);
	      ent->blacklist.size = 0;
	      return;
	    }
	  ent->blacklist.data = tmp;
	}
    }

  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
  *tmp++ = '|';
  *tmp = '\0';
  ent->blacklist.current += namelen + 1;

  return;
}

/* returns TRUE if ent->blacklist contains name, else FALSE */
static bool_t
in_blacklist (const char *name, int namelen, ent_t *ent)
{
  char buf[namelen + 3];

  if (ent->blacklist.data == NULL)
    return FALSE;

  stpcpy (stpcpy (stpcpy (buf, "|"), name), "|");
  return strstr (ent->blacklist.data, buf) != NULL;
}