source: MondoRescue/branches/3.3/mindi-busybox/loginutils/addgroup.c@ 3624

/* 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 source tree.
 *
 */
//config:config ADDGROUP
//config:   bool "addgroup"
//config:   default y
//config:   help
//config:     Utility for creating a new group account.
//config:
//config:config FEATURE_ADDGROUP_LONG_OPTIONS
//config:   bool "Enable long options"
//config:   default y
//config:   depends on ADDGROUP && LONG_OPTS
//config:   help
//config:     Support long options for the addgroup applet.
//config:
//config:config FEATURE_ADDUSER_TO_GROUP
//config:   bool "Support for adding users to groups"
//config:   default y
//config:   depends on ADDGROUP
//config:   help
//config:     If  called  with two non-option arguments,
//config:     addgroup will add an existing user to an
//config:     existing group.

//applet:IF_ADDGROUP(APPLET(addgroup, BB_DIR_USR_SBIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_ADDGROUP) += addgroup.o

//usage:#define addgroup_trivial_usage
//usage:       "[-g GID] [-S] " IF_FEATURE_ADDUSER_TO_GROUP("[USER] ") "GROUP"
//usage:#define addgroup_full_usage "\n\n"
//usage:       "Add a group" IF_FEATURE_ADDUSER_TO_GROUP(" or add a user to a group") "\n"
//usage:     "\n    -g GID  Group id"
//usage:     "\n    -S  Create a system group"

#include "libbb.h"

#if CONFIG_LAST_SYSTEM_ID < CONFIG_FIRST_SYSTEM_ID
#error Bad LAST_SYSTEM_ID or FIRST_SYSTEM_ID in .config
#endif
#if CONFIG_LAST_ID < CONFIG_LAST_SYSTEM_ID
#error Bad LAST_ID or LAST_SYSTEM_ID in .config
#endif

#define OPT_GID                       (1 << 0)
#define OPT_SYSTEM_ACCOUNT            (1 << 1)

static void xgroup_study(struct group *g)
{
    unsigned max = CONFIG_LAST_ID;

    /* Make sure gr_name is unused */
    if (getgrnam(g->gr_name)) {
        bb_error_msg_and_die("%s '%s' in use", "group", g->gr_name);
        /* these format strings are reused in adduser and addgroup */
    }

    /* if a specific gid is requested, the --system switch and */
    /* min and max values are overridden, and the range of valid */
    /* gid values is set to [0, INT_MAX] */
    if (!(option_mask32 & OPT_GID)) {
        if (option_mask32 & OPT_SYSTEM_ACCOUNT) {
            g->gr_gid = CONFIG_FIRST_SYSTEM_ID;
            max = CONFIG_LAST_SYSTEM_ID;
        } else {
            g->gr_gid = CONFIG_LAST_SYSTEM_ID + 1;
        }
    }
    /* 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 & OPT_GID) {
            /* -g N, cannot pick gid other than N: error */
            bb_error_msg_and_die("%s '%s' in use", "gid", itoa(g->gr_gid));
            /* this format strings is reused in adduser and addgroup */
        }
        if (g->gr_gid == max) {
            /* overflowed: error */
            bb_error_msg_and_die("no %cids left", 'g');
            /* this format string is reused in adduser and addgroup */
        }
        g->gr_gid++;
    }
}

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

    /* 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 */
    p = xasprintf("x:%u:", (unsigned) gr.gr_gid);
    if (update_passwd(bb_path_group_file, group, p, NULL) < 0)
        exit(EXIT_FAILURE);
    if (ENABLE_FEATURE_CLEAN_UP)
        free(p);
#if ENABLE_FEATURE_SHADOWPASSWDS
    /* /etc/gshadow fields:
     * 1. Group name.
     * 2. Encrypted password.
     *    If set, non-members of the group can join the group
     *    by typing the password for that group using the newgrp command.
     *    If the value is of this field ! then no user is allowed
     *    to access the group using the newgrp command. A value of !!
     *    is treated the same as a value of ! only it indicates
     *    that a password has never been set before. If the value is null,
     *    only group members can log into the group.
     * 3. Group administrators (comma delimited list).
     *    Group members listed here can add or remove group members
     *    using the gpasswd command.
     * 4. Group members (comma delimited list).
     */
    /* Ignore errors: if file is missing we assume admin doesn't want it */
    update_passwd(bb_path_gshadow_file, group, "!::", NULL);
#endif
}

#if ENABLE_FEATURE_ADDGROUP_LONG_OPTIONS
static const char addgroup_longopts[] ALIGN1 =
        "gid\0"                 Required_argument "g"
        "system\0"              No_argument       "S"
        ;
#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) MAIN_EXTERNALLY_VISIBLE;
int addgroup_main(int argc UNUSED_PARAM, char **argv)
{
    unsigned opts;
    const char *gid = "0";

    /* need to be root */
    if (geteuid()) {
        bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
    }
#if ENABLE_FEATURE_ADDGROUP_LONG_OPTIONS
    applet_long_options = addgroup_longopts;
#endif
    /* Syntax:
     *  addgroup group
     *  addgroup -g num group
     *  addgroup user group
     * Check for min, max and missing args */
    opt_complementary = "-1:?2";
    opts = getopt32(argv, "g:S", &gid);
    /* move past the commandline options */
    argv += optind;
    //argc -= optind;

#if ENABLE_FEATURE_ADDUSER_TO_GROUP
    if (argv[1]) {
        struct group *gr;

        if (opts & OPT_GID) {
            /* -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 */
        gr = xgetgrnam(argv[1]); /* unknown group: exit */
        /* check if user is already in this group */
        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;
            }
        }
        if (update_passwd(bb_path_group_file, argv[1], NULL, argv[0]) < 0) {
            return EXIT_FAILURE;
        }
# if ENABLE_FEATURE_SHADOWPASSWDS
        update_passwd(bb_path_gshadow_file, argv[1], NULL, argv[0]);
# endif
    } else
#endif /* ENABLE_FEATURE_ADDUSER_TO_GROUP */
    {
        die_if_bad_username(argv[0]);
        new_group(argv[0], xatou_range(gid, 0, CONFIG_LAST_ID));
    }
    /* Reached only on success */
    return EXIT_SUCCESS;
}