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/*

 * __getgrent.c - This file is part of the libc-8086/grp package for ELKS,

 * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.

 *

 *  This 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.

 *

 *  This 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 this library; if not, write to the Free

 *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 *

 */

#include <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <grp.h>

#include "config.h"

/*

 * This is the core group-file read function.  It behaves exactly like

 * getgrent() except that it is passed a file descriptor.  getgrent()

 * is just a wrapper for this function.

 */

struct group *

__getgrent(int grp_fd)

{

#ifndef GR_SCALE_DYNAMIC  

  static char line_buff[GR_MAX_LINE_LEN];

  static char * members[GR_MAX_MEMBERS];

#else

  static char * line_buff = NULL;

  static char ** members = NULL;

  short line_index;

  short buff_size;

#endif

  static struct group group;

  register char * ptr;

  char * field_begin;

  short member_num;

  char * endptr;

  int line_len;

  /* We use the restart label to handle malformatted lines */

restart:

#ifdef GR_SCALE_DYNAMIC

  line_index=0;

  buff_size=256;

#endif

#ifndef GR_SCALE_DYNAMIC

  /* Read the line into the static buffer */

  if ((line_len=read(grp_fd, line_buff, GR_MAX_LINE_LEN))<=0)

    return NULL;

  field_begin=strchr(line_buff, '\n');

  if (field_begin!=NULL)

    lseek(grp_fd, (long) (1+field_begin-(line_buff+line_len)), SEEK_CUR);

  else /* The line is too long - skip it :-\ */

    {

      do { if ((line_len=read(grp_fd, line_buff, GR_MAX_LINE_LEN))<=0)

        return NULL;

      } while (!(field_begin=strchr(line_buff, '\n')));

      lseek(grp_fd, (long) ((field_begin-line_buff)-line_len+1), SEEK_CUR);

      goto restart;

    }

  if (*line_buff=='#' || *line_buff==' ' || *line_buff=='\n' ||

      *line_buff=='\t')

    goto restart;

  *field_begin='\0';

#else /* !GR_SCALE_DYNAMIC */

  line_buff=realloc(line_buff, buff_size);

  while (1)

    {

      if ((line_len=read(grp_fd, line_buff+line_index,

                         buff_size-line_index))<=0)

          return NULL;

      field_begin=strchr(line_buff, '\n');

      if (field_begin!=NULL)

        {

          lseek(grp_fd, (long) (1+field_begin-(line_len+line_index+line_buff)),

                SEEK_CUR);

          *field_begin='\0';

          if (*line_buff=='#' || *line_buff==' ' || *line_buff=='\n' ||

              *line_buff=='\t')

            goto restart;

          break;

        }

      else /* Allocate some more space */

        {

          line_index=buff_size;

          buff_size+=256;

          line_buff=realloc(line_buff, buff_size);

        }

    }

#endif /* GR_SCALE_DYNAMIC */

  /* Now parse the line */

  group.gr_name=line_buff;

  ptr=strchr(line_buff, ':');

  if (ptr==NULL) goto restart;

  *ptr++='\0';

  group.gr_passwd=ptr;

  ptr=strchr(ptr, ':');

  if (ptr==NULL) goto restart;

  *ptr++='\0';

  field_begin=ptr;

  ptr=strchr(ptr, ':');

  if (ptr==NULL) goto restart;

  *ptr++='\0';

  group.gr_gid=(gid_t) strtoul(field_begin, &endptr, 10);

  if (*endptr!='\0') goto restart;

  member_num=0;

  field_begin=ptr;

#ifndef GR_SCALE_DYNAMIC

  while ((ptr=strchr(ptr, ','))!=NULL)

    {

      *ptr='\0';

      ptr++;

      members[member_num]=field_begin;

      field_begin=ptr;

      member_num++;

    }

  if (*field_begin=='\0')

    members[member_num]=NULL;

  else

    {

      members[member_num]=field_begin;

      members[member_num+1]=NULL;

    }

#else /* !GR_SCALE_DYNAMIC */

  if (members!=NULL)

    free (members);

  members=(char **) malloc(1*sizeof(char *));

  while ((ptr=strchr(ptr, ','))!=NULL)

    {

      *ptr='\0';

      ptr++;

      members[member_num]=field_begin;

      field_begin=ptr;

      member_num++;

      members=(char **)realloc((void *)members, (member_num+1)*sizeof(char *));

    }

  if (*field_begin=='\0')

      members[member_num]=NULL;

  else

    {

      members[member_num]=field_begin;

      members[member_num+1]=NULL;

    }

#endif /* GR_SCALE_DYNAMIC */

  group.gr_mem=members;

  return &group;

}