coreutils/id.c - busybox - Git at Google

 /* 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);
 }
	/* 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);
	}