source: MondoRescue/branches/2.2.5/mindi-busybox/loginutils/addgroup.c

/* vi: set sw=4 ts=4: */
/*
 * addgroup - add groups to /etc/group and /etc/gshadow
 *
 * Copyright (C) 1999 by Lineo, inc. and John Beppu
 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
 * Copyright (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 */

#include "libbb.h"

static void xgroup_study(struct group *g)
{
    /* Make sure gr_name is unused */
    if (getgrnam(g->gr_name)) {
        goto error;
    }

    /* Check if the desired gid is free
     * or find the first free one */
    while (1) {
        if (!getgrgid(g->gr_gid)) {
            return; /* found free group: return */
        }
        if (option_mask32) {
            /* -g N, cannot pick gid other than N: error */
            g->gr_name = itoa(g->gr_gid);
            goto error;
        }
        g->gr_gid++;
        if (g->gr_gid <= 0) {
            /* overflowed: error */
            bb_error_msg_and_die("no gids left");
        }
    }

 error:
    /* exit */
    bb_error_msg_and_die("group %s already exists", g->gr_name);
}

/* append a new user to the passwd file */
static void new_group(char *group, gid_t gid)
{
    FILE *file;
    struct group gr;

    /* make sure gid and group haven't already been allocated */
    gr.gr_gid = gid;
    gr.gr_name = group;
    xgroup_study(&gr);

    /* add entry to group */
    file = xfopen(bb_path_group_file, "a");
    /* group:passwd:gid:userlist */
    fprintf(file, "%s:x:%d:\n", group, gr.gr_gid);
    if (ENABLE_FEATURE_CLEAN_UP)
        fclose(file);
#if ENABLE_FEATURE_SHADOWPASSWDS
    file = fopen_or_warn(bb_path_gshadow_file, "a");
    if (file) {
        fprintf(file, "%s:!::\n", group);
        if (ENABLE_FEATURE_CLEAN_UP)
            fclose(file);
    }
#endif
}

#if ENABLE_FEATURE_ADDUSER_TO_GROUP
static void add_user_to_group(char **args,
        const char *path,
        FILE *(*fopen_func)(const char *fileName, const char *mode))
{
    char *line;
    int len = strlen(args[1]);
    llist_t *plist = NULL;
    FILE *group_file;

    group_file = fopen_func(path, "r");

    if (!group_file) return;

    while ((line = xmalloc_getline(group_file))) {
        /* Find the group */
        if (!strncmp(line, args[1], len)
         && line[len] == ':'
        ) {
            /* Add the new user */
            line = xasprintf("%s%s%s", line,
                        last_char_is(line, ':') ? "" : ",",
                        args[0]);
        }
        llist_add_to_end(&plist, line);
    }

    if (ENABLE_FEATURE_CLEAN_UP) {
        fclose(group_file);
        group_file = fopen_func(path, "w");
        while ((line = llist_pop(&plist))) {
            if (group_file)
                fprintf(group_file, "%s\n", line);
            free(line);
        }
        if (group_file)
            fclose(group_file);
    } else {
        group_file = fopen_func(path, "w");
        if (group_file)
            while ((line = llist_pop(&plist)))
                fprintf(group_file, "%s\n", line);
    }
}
#endif

/*
 * addgroup will take a login_name as its first parameter.
 *
 * gid can be customized via command-line parameters.
 * If called with two non-option arguments, addgroup
 * will add an existing user to an existing group.
 */
int addgroup_main(int argc, char **argv);
int addgroup_main(int argc, char **argv)
{
    char *group;
    gid_t gid = 0;

    /* need to be root */
    if (geteuid()) {
        bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
    }

    /* Syntax:
     *  addgroup group
     *  addgroup -g num group
     *  addgroup user group
     * Check for min, max and missing args */
    opt_complementary = "-1:?2";
    if (getopt32(argv, "g:", &group)) {
        gid = xatoul_range(group, 0, ((unsigned long)(gid_t)ULONG_MAX) >> 1);
    }
    /* move past the commandline options */
    argv += optind;
    argc -= optind;

#if ENABLE_FEATURE_ADDUSER_TO_GROUP
    if (argc == 2) {
        struct group *gr;

        if (option_mask32) {
            /* -g was there, but "addgroup -g num user group"
             * is a no-no */
            bb_show_usage();
        }

        /* check if group and user exist */
        xuname2uid(argv[0]); /* unknown user: exit */
        xgroup2gid(argv[1]); /* unknown group: exit */
        /* check if user is already in this group */
        gr = getgrnam(argv[1]);
        for (; *(gr->gr_mem) != NULL; (gr->gr_mem)++) {
            if (!strcmp(argv[0], *(gr->gr_mem))) {
                /* user is already in group: do nothing */
                return EXIT_SUCCESS;
            }
        }
        add_user_to_group(argv, bb_path_group_file, xfopen);
#if ENABLE_FEATURE_SHADOWPASSWDS
        add_user_to_group(argv, bb_path_gshadow_file, fopen_or_warn);
#endif /* ENABLE_FEATURE_SHADOWPASSWDS */
    } else
#endif /* ENABLE_FEATURE_ADDUSER_TO_GROUP */
        new_group(argv[0], gid);

    /* Reached only on success */
    return EXIT_SUCCESS;
}