ucbcmd/groups/groups.c

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

/*
 * groups
 */

#include <sys/types.h>
#include <sys/param.h>
#include <alloca.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

static void showgroups(char *user);

int
main(int argc, char *argv[])
{
    int ngroups, i;
    char *sep = "";
    struct group *gr;
    gid_t *groups;
    int maxgrp = sysconf(_SC_NGROUPS_MAX);

    groups = alloca(maxgrp * sizeof (gid_t));

    if (argc > 1) {
        for (i = 1; i < argc; i++)
            showgroups(argv[i]);
        exit(0);
    }

    ngroups = getgroups(maxgrp, groups);
    if (getpwuid(getuid()) == NULL) {
        (void) fprintf(stderr, "groups: could not find passwd entry\n");
        exit(1);
    }

    for (i = 0; i < ngroups; i++) {
        gr = getgrgid(groups[i]);
        if (gr == NULL) {
            (void) printf("%s%u", sep, groups[i]);
            sep = " ";
            continue;
        }
        (void) printf("%s%s", sep, gr->gr_name);
        sep = " ";
    }

    (void) printf("\n");
    return (0);
}

static void
showgroups(char *user)
{
    struct group *gr;
    struct passwd *pw;
    char **cp;
    char *sep = "";
    int pwgid_printed = 0;

    if ((pw = getpwnam(user)) == NULL) {
        (void) fprintf(stderr, "groups: %s : No such user\n", user);
        return;
    }
    setgrent();
    (void) printf("%s : ", user);
    while (gr = getgrent()) {
        if (pw->pw_gid == gr->gr_gid) {
            /*
             * To avoid duplicate group entries
             */
            if (pwgid_printed == 0) {
                (void) printf("%s%s", sep, gr->gr_name);
                sep = " ";
                pwgid_printed = 1;
            }
            continue;
        }
        for (cp = gr->gr_mem; cp && *cp; cp++)
            if (strcmp(*cp, user) == 0) {
                (void) printf("%s%s", sep, gr->gr_name);
                sep = " ";
                break;
            }
    }
    (void) printf("\n");
    endgrent();
}