blob: f20cd7d09e0e30ab69443540a8ae57e28cdb8cf6 [file] [log] [blame]
/* vi: set sw=4 ts=4: */
/*
* Mini id implementation for busybox
*
* Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
* Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
* length and to be more similar to GNU id.
* -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
* Added -G option Tito Ragusa (C) 2008 for SUSv3.
*/
//config:config ID
//config: bool "id (7 kb)"
//config: default y
//config: help
//config: id displays the current user and group ID names.
//config:
//config:config GROUPS
//config: bool "groups (6.7 kb)"
//config: default y
//config: help
//config: Print the group names associated with current user id.
//applet:IF_GROUPS(APPLET_NOEXEC(groups, id, BB_DIR_USR_BIN, BB_SUID_DROP, groups))
//applet:IF_ID( APPLET_NOEXEC(id, id, BB_DIR_USR_BIN, BB_SUID_DROP, id ))
//kbuild:lib-$(CONFIG_GROUPS) += id.o
//kbuild:lib-$(CONFIG_ID) += id.o
/* BB_AUDIT SUSv3 compliant. */
//usage:#define id_trivial_usage
//usage: "[OPTIONS] [USER]"
//usage:#define id_full_usage "\n\n"
//usage: "Print information about USER or the current user\n"
//usage: IF_SELINUX(
//usage: "\n -Z Security context"
//usage: )
//usage: "\n -u User ID"
//usage: "\n -g Group ID"
//usage: "\n -G Supplementary group IDs"
//usage: "\n -n Print names instead of numbers"
//usage: "\n -r Print real ID instead of effective ID"
//usage:
//usage:#define id_example_usage
//usage: "$ id\n"
//usage: "uid=1000(andersen) gid=1000(andersen)\n"
//usage:#define groups_trivial_usage
//usage: "[USER]"
//usage:#define groups_full_usage "\n\n"
//usage: "Print the group memberships of USER or for the current process"
//usage:
//usage:#define groups_example_usage
//usage: "$ groups\n"
//usage: "andersen lp dialout cdrom floppy\n"
#include "libbb.h"
/* This is a NOEXEC applet. Be very careful! */
#if !ENABLE_USE_BB_PWD_GRP
#if defined(__UCLIBC__) && UCLIBC_VERSION < KERNEL_VERSION(0, 9, 30)
#error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
#endif
#endif
enum {
PRINT_REAL = (1 << 0),
NAME_NOT_NUMBER = (1 << 1),
JUST_USER = (1 << 2),
JUST_GROUP = (1 << 3),
JUST_ALL_GROUPS = (1 << 4),
#if ENABLE_SELINUX
JUST_CONTEXT = (1 << 5),
#endif
};
static int print_common(unsigned id, const char *name, const char *prefix)
{
if (prefix) {
printf("%s", prefix);
}
if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
printf("%u", id);
}
if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
if (name) {
printf(option_mask32 ? "%s" : "(%s)", name);
} else {
/* Don't set error status flag in default mode */
if (option_mask32) {
if (ENABLE_DESKTOP)
bb_error_msg("unknown ID %u", id);
return EXIT_FAILURE;
}
}
}
return EXIT_SUCCESS;
}
static int print_group(gid_t id, const char *prefix)
{
return print_common(id, gid2group(id), prefix);
}
static int print_user(uid_t id, const char *prefix)
{
return print_common(id, uid2uname(id), prefix);
}
/* On error set *n < 0 and return >= 0
* If *n is too small, update it and return < 0
* (ok to trash groups[] in both cases)
* Otherwise fill in groups[] and return >= 0
*/
static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
{
int m;
if (username) {
/* If the user is a member of more than
* *n groups, then -1 is returned. Otherwise >= 0.
* (and no defined way of detecting errors?!) */
m = getgrouplist(username, rgid, groups, n);
/* I guess *n < 0 might indicate error. Anyway,
* malloc'ing -1 bytes won't be good, so: */
if (*n < 0)
return 0;
return m;
}
*n = getgroups(*n, groups);
if (*n >= 0)
return *n;
/* Error */
if (errno == EINVAL) /* *n is too small? */
*n = getgroups(0, groups); /* get needed *n */
/* if *n >= 0, return -1 (got new *n), else return 0 (error): */
return -(*n >= 0);
}
int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int id_main(int argc UNUSED_PARAM, char **argv)
{
uid_t ruid;
gid_t rgid;
uid_t euid;
gid_t egid;
unsigned opt;
int i;
int status = EXIT_SUCCESS;
const char *prefix;
const char *username;
#if ENABLE_SELINUX
security_context_t scontext = NULL;
#endif
if (ENABLE_GROUPS && (!ENABLE_ID || applet_name[0] == 'g')) {
/* TODO: coreutils groups prepend "USER : " prefix,
* and accept many usernames. Example:
* # groups root root
* root : root
* root : root
*/
opt = option_mask32 = getopt32(argv, "") | JUST_ALL_GROUPS | NAME_NOT_NUMBER;
} else {
/* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
/* Don't allow more than one username */
opt = getopt32(argv, "^"
"rnugG" IF_SELINUX("Z")
"\0"
"?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G")
);
}
username = argv[optind];
if (username) {
struct passwd *p = xgetpwnam(username);
euid = ruid = p->pw_uid;
egid = rgid = p->pw_gid;
} else {
egid = getegid();
rgid = getgid();
euid = geteuid();
ruid = getuid();
}
/* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
/* id says: print the real ID instead of the effective ID, with -ugG */
/* in fact in this case egid is always printed if egid != rgid */
if (!opt || (opt & JUST_ALL_GROUPS)) {
gid_t *groups;
int n;
if (!opt) {
/* Default Mode */
status |= print_user(ruid, "uid=");
status |= print_group(rgid, " gid=");
if (euid != ruid)
status |= print_user(euid, " euid=");
if (egid != rgid)
status |= print_group(egid, " egid=");
} else {
/* JUST_ALL_GROUPS */
status |= print_group(rgid, NULL);
if (egid != rgid)
status |= print_group(egid, " ");
}
/* We are supplying largish buffer, trying
* to not run get_groups() twice. That might be slow
* ("user database in remote SQL server" case) */
groups = xmalloc(64 * sizeof(groups[0]));
n = 64;
if (get_groups(username, rgid, groups, &n) < 0) {
/* Need bigger buffer after all */
groups = xrealloc(groups, n * sizeof(groups[0]));
get_groups(username, rgid, groups, &n);
}
if (n > 0) {
/* Print the list */
prefix = " groups=";
for (i = 0; i < n; i++) {
if (opt && (groups[i] == rgid || groups[i] == egid))
continue;
status |= print_group(groups[i], opt ? " " : prefix);
prefix = ",";
}
} else if (n < 0) { /* error in get_groups() */
if (ENABLE_DESKTOP)
bb_simple_error_msg_and_die("can't get groups");
return EXIT_FAILURE;
}
if (ENABLE_FEATURE_CLEAN_UP)
free(groups);
#if ENABLE_SELINUX
if (is_selinux_enabled()) {
if (getcon(&scontext) == 0)
printf(" context=%s", scontext);
}
#endif
} else if (opt & PRINT_REAL) {
euid = ruid;
egid = rgid;
}
if (opt & JUST_USER)
status |= print_user(euid, NULL);
else if (opt & JUST_GROUP)
status |= print_group(egid, NULL);
#if ENABLE_SELINUX
else if (opt & JUST_CONTEXT) {
selinux_or_die();
if (username || getcon(&scontext)) {
bb_error_msg_and_die("can't get process context%s",
username ? " for a different user" : "");
}
fputs(scontext, stdout);
}
/* freecon(NULL) seems to be harmless */
if (ENABLE_FEATURE_CLEAN_UP)
freecon(scontext);
#endif
bb_putchar('\n');
fflush_stdout_and_exit(status);
}