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

#include "nss-nisplus.h"

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

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

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

struct ent_t
  {
    bool_t nis;
    bool_t nis_first;
    char *oldkey;
    int oldkeylen;
    nis_result *result;
    nis_name *names;
    u_long names_nr;
    FILE *stream;
    struct blacklist_t blacklist;
};
typedef struct ent_t ent_t;

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

/* 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_grent (nis_result *, struct group *,
				     char *, size_t);

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

  ent->nis = ent->nis_first = 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';

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

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

  return status;
}


enum nss_status
_nss_compat_setgrent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

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

  result = internal_setgrent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}


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

  ent->nis = ent->nis_first = 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';

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_endgrent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  result = internal_endgrent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}

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

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

  do
    {
      if (ent->nis_first)
	{
	  if (yp_first (domain, "group.byname", &outkey, &outkeylen,
			&outval, &outvallen) != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      return NSS_STATUS_UNAVAIL;
	    }

	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	  ent->nis_first = FALSE;
	}
      else
	{
	  if (yp_next (domain, "group.byname", ent->oldkey, ent->oldkeylen,
		       &outkey, &outkeylen, &outval, &outvallen)
	      != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      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_grent (p, result, data, buflen);

      if (parse_res &&
	  in_blacklist (result->gr_name, strlen (result->gr_name), ent))
	parse_res = 0; /* if result->gr_name in blacklist,search next entry */
    }
  while (!parse_res);

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getgrent_next_nisplus (struct group *result, ent_t *ent, char *buffer,
                       size_t buflen)
{
  int parse_res;

  if (ent->names == NULL)
    {
      ent->names = nis_getnames ("group.org_dir");
      if (ent->names == NULL || ent->names[0] == NULL)
        {
          ent->nis = 0;
          return NSS_STATUS_UNAVAIL;
        }
    }

  do
    {
      if (ent->nis_first)
        {
	next_name:
          ent->result = nis_first_entry(ent->names[ent->names_nr]);
          if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
            {
              ent->nis = 0;
              return niserr2nss (ent->result->status);
            }
          ent->nis_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;
                  return niserr2nss (ent->result->status);
                }
            }
        }
      parse_res = _nss_nisplus_parse_grent (ent->result, result, buffer,
                                            buflen);
      if (parse_res &&
          in_blacklist (result->gr_name, strlen (result->gr_name), ent))
        parse_res = 0; /* if result->gr_name in blacklist,search next entry */
    }
  while (!parse_res);

  return NSS_STATUS_SUCCESS;
}

/* This function handle the +group entrys in /etc/group */
static enum nss_status
getgrent_next_file_plusgroup (struct group *result, char *buffer,
			      size_t buflen)
{
  struct parser_data *data = (void *) buffer;
  int parse_res;

  if (use_nisplus) /* Do the NIS+ query here */
    {
      nis_result *res;
      char buf[strlen (result->gr_name) + 24];

      sprintf(buf, "[name=%s],group.org_dir",
              &result->gr_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_grent (res, result, buffer, buflen);
      nis_freeresult (res);
    }
  else /* Use NIS */
    {
      char *domain, *outval, *p;
      int outvallen;

      if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
        return NSS_STATUS_TRYAGAIN;

      if (yp_match (domain, "group.byname", &result->gr_name[1],
                    strlen (result->gr_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_grent (p, result, data, buflen);
    }

  if (parse_res)
    /* We found the entry.  */
    return NSS_STATUS_SUCCESS;
  else
    return NSS_STATUS_RETURN;
}


static enum nss_status
getgrent_next_file (struct group *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;
	}
      /* Ignore empty and comment lines.  */
      while (*p == '\0' || *p == '#' ||
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !_nss_files_parse_grent (p, result, data, buflen));

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

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

      /* +group */
      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
	  && result->gr_name[1] != '@')
	{
          enum nss_status status;

          status = getgrent_next_file_plusgroup (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->gr_name[0] == '+' && result->gr_name[1] == '\0')
	{
	  ent->nis = TRUE;
	  ent->nis_first = TRUE;

	  if (use_nisplus)
	    return getgrent_next_nisplus (result, ent, buffer, buflen);
	  else
	    return getgrent_next_nis (result, ent, buffer, buflen);
	}
    }

  return NSS_STATUS_SUCCESS;
}


static enum nss_status
internal_getgrent_r (struct group *gr, ent_t *ent, char *buffer,
		     size_t buflen)
{
  if (ent->nis)
    {
      if (use_nisplus)
	return getgrent_next_nisplus (gr, ent, buffer, buflen);
      else
	return getgrent_next_nis (gr, ent, buffer, buflen);
    }
  else
    return getgrent_next_file (gr, ent, buffer, buflen);
}

enum nss_status
_nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  __libc_lock_lock (lock);

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

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

  if (status == NSS_STATUS_SUCCESS)
    status = internal_getgrent_r (grp, &ext_ent, buffer, buflen);

  __libc_lock_unlock (lock);

  return status;
}


enum nss_status
_nss_compat_getgrnam_r (const char *name, struct group *grp,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, NULL, 0, NULL, NULL, 0, NULL, {NULL, 0, 0}};
  enum nss_status status;

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

  __libc_lock_lock (lock);

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

  __libc_lock_unlock (lock);

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

  while ((status = internal_getgrent_r (grp, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (strcmp (grp->gr_name, name) == 0)
      break;

  internal_endgrent (&ent);
  return status;
}


enum nss_status
_nss_compat_getgrgid_r (gid_t gid, struct group *grp,
			char *buffer, size_t buflen)
{
  ent_t ent = {0, 0, NULL, 0, NULL, NULL, 0, NULL, {NULL, 0, 0}};
  enum nss_status status;

  __libc_lock_lock (lock);

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

  __libc_lock_unlock (lock);

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

  while ((status = internal_getgrent_r (grp, &ent, buffer, buflen))
	 == NSS_STATUS_SUCCESS)
    if (grp->gr_gid == gid && grp->gr_name[0] != '+' && grp->gr_name[0] != '-')
      break;

  internal_endgrent (&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];
  char *cp;

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

  buf[0] = '|';
  cp = stpcpy (&buf[1], name);
  *cp++= '|';
  *cp = '\0';
  return strstr (ent->blacklist.data, buf) != NULL;
}