busybox/loginutils/addgroup.c
Denis Vlasenko f1f1b69dc1 addgroup: "disallow addgroup -g num user group"; make -g 0 work
(Tito <farmatito@tiscali.it>)
2007-07-30 12:32:37 +00:00

181 lines
4.2 KiB
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(argc, 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;
}