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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 "busybox.h"
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "grp_.h"
/*
* Define GR_SCALE_DYNAMIC if you want grp to dynamically scale its read buffer
* so that lines of any length can be used. On very very small systems,
* you may want to leave this undefined becasue it will make the grp functions
* somewhat larger (because of the inclusion of malloc and the code necessary).
* On larger systems, you will want to define this, because grp will _not_
* deal with long lines gracefully (they will be skipped).
*/
#undef GR_SCALE_DYNAMIC
#ifndef GR_SCALE_DYNAMIC
/*
* If scaling is not dynamic, the buffers will be statically allocated, and
* maximums must be chosen. GR_MAX_LINE_LEN is the maximum number of
* characters per line in the group file. GR_MAX_MEMBERS is the maximum
* number of members of any given group.
*/
#define GR_MAX_LINE_LEN 128
/* GR_MAX_MEMBERS = (GR_MAX_LINE_LEN-(24+3+6))/9 */
#define GR_MAX_MEMBERS 11
#endif /* !GR_SCALE_DYNAMIC */
/*
* Define GR_DYNAMIC_GROUP_LIST to make initgroups() dynamically allocate
* space for it's GID array before calling setgroups(). This is probably
* unnecessary scalage, so it's undefined by default.
*/
#undef GR_DYNAMIC_GROUP_LIST
#ifndef GR_DYNAMIC_GROUP_LIST
/*
* GR_MAX_GROUPS is the size of the static array initgroups() uses for
* its static GID array if GR_DYNAMIC_GROUP_LIST isn't defined.
*/
#define GR_MAX_GROUPS 64
#endif /* !GR_DYNAMIC_GROUP_LIST */
/*
* 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 */
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;
}
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