116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
/*
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* initgroups.c - This file is part of the libc-8086/grp package for ELKS,
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* Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include "busybox.h"
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include "grp_.h"
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/*
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* Define GR_SCALE_DYNAMIC if you want grp to dynamically scale its read buffer
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* so that lines of any length can be used. On very very small systems,
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* you may want to leave this undefined becasue it will make the grp functions
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* somewhat larger (because of the inclusion of malloc and the code necessary).
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* On larger systems, you will want to define this, because grp will _not_
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* deal with long lines gracefully (they will be skipped).
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*/
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#undef GR_SCALE_DYNAMIC
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#ifndef GR_SCALE_DYNAMIC
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/*
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* If scaling is not dynamic, the buffers will be statically allocated, and
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* maximums must be chosen. GR_MAX_LINE_LEN is the maximum number of
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* characters per line in the group file. GR_MAX_MEMBERS is the maximum
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* number of members of any given group.
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*/
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#define GR_MAX_LINE_LEN 128
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/* GR_MAX_MEMBERS = (GR_MAX_LINE_LEN-(24+3+6))/9 */
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#define GR_MAX_MEMBERS 11
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#endif /* !GR_SCALE_DYNAMIC */
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/*
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* Define GR_DYNAMIC_GROUP_LIST to make initgroups() dynamically allocate
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* space for it's GID array before calling setgroups(). This is probably
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* unnecessary scalage, so it's undefined by default.
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*/
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#undef GR_DYNAMIC_GROUP_LIST
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#ifndef GR_DYNAMIC_GROUP_LIST
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/*
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* GR_MAX_GROUPS is the size of the static array initgroups() uses for
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* its static GID array if GR_DYNAMIC_GROUP_LIST isn't defined.
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*/
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#define GR_MAX_GROUPS 64
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#endif /* !GR_DYNAMIC_GROUP_LIST */
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int initgroups(__const char *user, gid_t gid)
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{
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register struct group *group;
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#ifndef GR_DYNAMIC_GROUP_LIST
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gid_t group_list[GR_MAX_GROUPS];
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#else
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gid_t *group_list = NULL;
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#endif
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register char **tmp_mem;
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int num_groups;
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int grp_fd;
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if ((grp_fd = open("/etc/group", O_RDONLY)) < 0)
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return -1;
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num_groups = 0;
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#ifdef GR_DYNAMIC_GROUP_LIST
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group_list = (gid_t *) realloc(group_list, 1);
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#endif
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group_list[num_groups] = gid;
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#ifndef GR_DYNAMIC_GROUP_LIST
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while (num_groups < GR_MAX_GROUPS &&
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(group = __getgrent(grp_fd)) != NULL)
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#else
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while ((group = __getgrent(grp_fd)) != NULL)
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#endif
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{
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if (group->gr_gid != gid);
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{
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tmp_mem = group->gr_mem;
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while (*tmp_mem != NULL) {
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if (!strcmp(*tmp_mem, user)) {
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num_groups++;
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#ifdef GR_DYNAMIC_GROUP_LIST
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group_list = (gid_t *) realloc(group_list, num_groups *
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sizeof(gid_t *));
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#endif
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group_list[num_groups-1] = group->gr_gid;
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}
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tmp_mem++;
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}
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}
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}
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close(grp_fd);
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return setgroups(num_groups, group_list);
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}
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