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108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/* getugroups.c -- return a list of the groups a user is in
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Copyright (C) 1990, 1991, 1998, 1999, 2000, 2003, 2004 Free
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Software Foundation.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Written by David MacKenzie. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <sys/types.h>
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#include <stdio.h> /* grp.h on alpha OSF1 V2.0 uses "FILE *". */
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#include <grp.h>
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#include <unistd.h>
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#include <errno.h>
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#ifndef EOVERFLOW
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# define EOVERFLOW EINVAL
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#endif
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/* setgrent, getgrent, and endgrent are not specified by POSIX.1,
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so header files might not declare them.
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If you don't have them at all, we can't implement this function.
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You lose! */
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struct group *getgrent ();
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#include <string.h>
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#define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
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/* Like `getgroups', but for user USERNAME instead of for the current
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process. Store at most MAXCOUNT group IDs in the GROUPLIST array.
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If GID is not -1, store it first (if possible). GID should be the
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group ID (pw_gid) obtained from getpwuid, in case USERNAME is not
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listed in /etc/groups.
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Always return the number of groups of which USERNAME is a member. */
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int
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getugroups (int maxcount, GETGROUPS_T *grouplist, char *username, gid_t gid)
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{
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struct group *grp;
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register char **cp;
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register int count = 0;
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if (gid != (gid_t) -1)
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{
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if (maxcount != 0)
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grouplist[count] = gid;
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++count;
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}
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setgrent ();
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while ((grp = getgrent ()) != 0)
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{
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for (cp = grp->gr_mem; *cp; ++cp)
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{
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int n;
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if ( ! STREQ (username, *cp))
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continue;
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/* See if this group number is already on the list. */
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for (n = 0; n < count; ++n)
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if (grouplist && grouplist[n] == grp->gr_gid)
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break;
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/* If it's a new group number, then try to add it to the list. */
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if (n == count)
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{
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if (maxcount != 0)
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{
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if (count >= maxcount)
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{
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endgrent ();
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return count;
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}
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grouplist[count] = grp->gr_gid;
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}
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count++;
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if (count < 0)
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{
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errno = EOVERFLOW;
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return -1;
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}
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}
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}
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}
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endgrent ();
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return count;
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}
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