/* * __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;	int 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((member_num + 1) * sizeof(char *));	for ( ; field_begin && *field_begin != '\0'; field_begin = ptr) {	    if ((ptr = strchr(field_begin, ',')) != NULL)		*ptr++ = '\0';	    members[member_num++] = field_begin;	    members = (char **) realloc(members,		    (member_num + 1) * sizeof(char *));	}	members[member_num] = NULL;#endif							/* GR_SCALE_DYNAMIC */	group.gr_mem = members;	return &group;}