usr/src/lib/libc/gen/getgrouplist.c

/*
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getgrouplist.c      8.1 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

/*
 * get credential
 */
#include <sys/types.h>
#include <string.h>
#include <grp.h>

int
getgrouplist(uname, agroup, groups, grpcnt)
        const char *uname;
        int agroup;
        register int *groups;
        int *grpcnt;
{
        register struct group *grp;
        register struct passwd *pw;
        register int i, ngroups;
        int ret, maxgroups;

        ret = 0;
        ngroups = 0;
        maxgroups = *grpcnt;
        /*
         * When installing primary group, duplicate it;
         * the first element of groups is the effective gid
         * and will be overwritten when a setgid file is executed.
         */
        groups[ngroups++] = agroup;
        if (maxgroups > 1)
                groups[ngroups++] = agroup;
        /*
         * Scan the group file to find additional groups.
         */
        setgrent();
        while (grp = getgrent()) {
                if (grp->gr_gid == agroup)
                        continue;
                if (ngroups >= maxgroups) {
                        ret = -1;
                        break;
                }
                for (i = 0; grp->gr_mem[i]; i++) {
                        if (!strcmp(grp->gr_mem[i], uname)) {
                                groups[ngroups++] = grp->gr_gid;
                                break;
                        }
                }
        }
        endgrent();
        *grpcnt = ngroups;
        return (ret);
}