hush/loginutils/addgroup.c

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/* 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.
*
*/
//usage:#define addgroup_trivial_usage
//usage: "[-g GID] " 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
#define OPT_GID (1 << 0)
#define OPT_SYSTEM_ACCOUNT (1 << 1)
/* We assume GID_T_MAX == INT_MAX */
static void xgroup_study(struct group *g)
{
unsigned max = INT_MAX;
/* 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;
max = 64999;
}
}
/* 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);
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#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;
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int addgroup_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
unsigned gid = 0;
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/* 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:g+";
opts = getopt32(argv, "g:S", &gid);
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/* move past the commandline options */
argv += optind;
//argc -= optind;
#if ENABLE_FEATURE_ADDUSER_TO_GROUP
if (argv[1]) {
struct group *gr;
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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], gid);
}
/* Reached only on success */
return EXIT_SUCCESS;
}