busybox/coreutils/id.c
2008-10-29 00:27:31 +00:00

213 lines
5.5 KiB
C

/* 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 tarball for details.
*/
/* BB_AUDIT SUSv3 compliant. */
/* 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.
*/
#include "libbb.h"
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,
char* FAST_FUNC bb_getXXXid(char *name, int bufsize, long uid),
const char *prefix)
{
const char *name = bb_getXXXid(NULL, 0, id);
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, bb_getgrgid, prefix);
}
static int print_user(gid_t id, const char *prefix)
{
return print_common(id, bb_getpwuid, 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;
//commented here, happens below anyway
} else {
/* On error -1 is returned, which ends up in *n */
int nn = getgroups(*n, groups);
/* 0: nn <= *n, groups[] was big enough; -1 otherwise */
m = - (nn > *n);
*n = nn;
}
if (*n < 0)
return 0; /* error, don't return < 0! */
return m;
}
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
/* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
/* Don't allow more than one username */
opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
USE_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
opt = getopt32(argv, "rnugG" USE_SELINUX("Z"));
username = argv[optind];
if (username) {
struct passwd *p = getpwnam(username);
if (!p)
bb_error_msg_and_die("unknown user %s", 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 ths 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'd rather try supplying largish buffer than
* having get_groups() run twice. That might be slow
* (think about "user database in remove SQL server" case) */
groups = xmalloc(64 * sizeof(gid_t));
n = 64;
if (get_groups(username, rgid, groups, &n) < 0) {
/* Need bigger buffer after all */
groups = xrealloc(groups, n * sizeof(gid_t));
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 = ",";
}
if (ENABLE_FEATURE_CLEAN_UP)
free(groups);
} else if (n < 0) { /* error in get_groups() */
if (!ENABLE_DESKTOP)
bb_error_msg_and_die("cannot get groups");
else
return EXIT_FAILURE;
}
#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);
}