runit/chpst.c - codeaurora/busybox - Gitiles

 /*
 Copyright (c) 2001-2006, Gerrit Pape
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
    3. The name of the author may not be used to endorse or promote products
       derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

 /* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */
 /* Dependencies on runit_lib.c removed */

 #include "libbb.h"

 /*
 Five applets here: chpst, envdir, envuidgid, setuidgid, softlimit.

 Only softlimit and chpst are taking options:

 # common
 -o N            Limit number of open files per process
 -p N            Limit number of processes per uid
 -m BYTES        Same as -d BYTES -s BYTES -l BYTES [-a BYTES]
 -d BYTES        Limit data segment
 -f BYTES        Limit output file sizes
 -c BYTES        Limit core file size
 # softlimit
 -a BYTES        Limit total size of all segments
 -s BYTES        Limit stack segment
 -l BYTES        Limit locked memory size
 -r BYTES        Limit resident set size
 -t N            Limit CPU time
 # chpst
 -u USER[:GRP]   Set uid and gid
 -U USER[:GRP]   Set $UID and $GID in environment
 -e DIR          Set environment variables as specified by files in DIR
 -/ DIR          Chroot to DIR
 -n NICE         Add NICE to nice value
 -v              Verbose
 -P              Create new process group
 -0 -1 -2        Close fd 0,1,2

 Even though we accept all these options for both softlimit and chpst,
 they are not to be advertised on their help texts.
 We have enough problems with feature creep in other people's
 software, don't want to add our own.

 envdir, envuidgid, setuidgid take no options, but they reuse code which
 handles -e, -U and -u.
 */

 enum {
 	OPT_a = (1 << 0) * ENABLE_SOFTLIMIT,
 	OPT_c = (1 << 1) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_d = (1 << 2) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_f = (1 << 3) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_l = (1 << 4) * ENABLE_SOFTLIMIT,
 	OPT_m = (1 << 5) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_o = (1 << 6) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_p = (1 << 7) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
 	OPT_r = (1 << 8) * ENABLE_SOFTLIMIT,
 	OPT_s = (1 << 9) * ENABLE_SOFTLIMIT,
 	OPT_t = (1 << 10) * ENABLE_SOFTLIMIT,
 	OPT_u = (1 << 11) * (ENABLE_CHPST || ENABLE_SETUIDGID),
 	OPT_U = (1 << 12) * (ENABLE_CHPST || ENABLE_ENVUIDGID),
 	OPT_e = (1 << 13) * (ENABLE_CHPST || ENABLE_ENVDIR),
 	OPT_root = (1 << 14) * ENABLE_CHPST,
 	OPT_n = (1 << 15) * ENABLE_CHPST,
 	OPT_v = (1 << 16) * ENABLE_CHPST,
 	OPT_P = (1 << 17) * ENABLE_CHPST,
 	OPT_0 = (1 << 18) * ENABLE_CHPST,
 	OPT_1 = (1 << 19) * ENABLE_CHPST,
 	OPT_2 = (1 << 20) * ENABLE_CHPST,
 };

 /* TODO: use recursive_action? */
 static NOINLINE void edir(const char *directory_name)
 {
 	int wdir;
 	DIR *dir;
 	struct dirent *d;
 	int fd;

 	wdir = xopen(".", O_RDONLY | O_NDELAY);
 	xchdir(directory_name);
 	dir = xopendir(".");
 	for (;;) {
 		char buf[256];
 		char *tail;
 		int size;

 		errno = 0;
 		d = readdir(dir);
 		if (!d) {
 			if (errno)
 				bb_perror_msg_and_die("readdir %s",
 						directory_name);
 			break;
 		}
 		if (d->d_name[0] == '.')
 			continue;
 		fd = open(d->d_name, O_RDONLY | O_NDELAY);
 		if (fd < 0) {
 			if ((errno == EISDIR) && directory_name) {
 				if (option_mask32 & OPT_v)
 					bb_perror_msg("warning: %s/%s is a directory",
 						directory_name, d->d_name);
 				continue;
 			}
 			bb_perror_msg_and_die("open %s/%s",
 						directory_name, d->d_name);
 		}
 		size = full_read(fd, buf, sizeof(buf)-1);
 		close(fd);
 		if (size < 0)
 			bb_perror_msg_and_die("read %s/%s",
 					directory_name, d->d_name);
 		if (size == 0) {
 			unsetenv(d->d_name);
 			continue;
 		}
 		buf[size] = '\n';
 		tail = strchr(buf, '\n');
 		/* skip trailing whitespace */
 		while (1) {
 			*tail = '\0';
 			tail--;
 			if (tail < buf || !isspace(*tail))
 				break;
 		}
 		xsetenv(d->d_name, buf);
 	}
 	closedir(dir);
 	if (fchdir(wdir) == -1)
 		bb_perror_msg_and_die("fchdir");
 	close(wdir);
 }

 static void limit(int what, long l)
 {
 	struct rlimit r;

 	/* Never fails under Linux (except if you pass it bad arguments) */
 	getrlimit(what, &r);
 	if ((l < 0) || (l > r.rlim_max))
 		r.rlim_cur = r.rlim_max;
 	else
 		r.rlim_cur = l;
 	if (setrlimit(what, &r) == -1)
 		bb_perror_msg_and_die("setrlimit");
 }

 int chpst_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int chpst_main(int argc UNUSED_PARAM, char **argv)
 {
 	struct bb_uidgid_t ugid;
 	char *set_user = set_user; /* for compiler */
 	char *env_user = env_user;
 	char *env_dir = env_dir;
 	char *root;
 	char *nicestr;
 	unsigned limita;
 	unsigned limitc;
 	unsigned limitd;
 	unsigned limitf;
 	unsigned limitl;
 	unsigned limitm;
 	unsigned limito;
 	unsigned limitp;
 	unsigned limitr;
 	unsigned limits;
 	unsigned limitt;
 	unsigned opt;

 	if ((ENABLE_CHPST && applet_name[0] == 'c')
 	 || (ENABLE_SOFTLIMIT && applet_name[1] == 'o')
 	) {
 		// FIXME: can we live with int-sized limits?
 		// can we live with 40000 days?
 		// if yes -> getopt converts strings to numbers for us
 		opt_complementary = "-1:a+:c+:d+:f+:l+:m+:o+:p+:r+:s+:t+";
 		opt = getopt32(argv, "+a:c:d:f:l:m:o:p:r:s:t:u:U:e:"
 			IF_CHPST("/:n:vP012"),
 			&limita, &limitc, &limitd, &limitf, &limitl,
 			&limitm, &limito, &limitp, &limitr, &limits, &limitt,
 			&set_user, &env_user, &env_dir
 			IF_CHPST(, &root, &nicestr));
 		argv += optind;
 		if (opt & OPT_m) { // -m means -asld
 			limita = limits = limitl = limitd = limitm;
 			opt |= (OPT_s | OPT_l | OPT_a | OPT_d);
 		}
 	} else {
 		option_mask32 = opt = 0;
 		argv++;
 		if (!*argv)
 			bb_show_usage();
 	}

 	// envdir?
 	if (ENABLE_ENVDIR && applet_name[3] == 'd') {
 		env_dir = *argv++;
 		opt |= OPT_e;
 	}

 	// setuidgid?
 	if (ENABLE_SETUIDGID && applet_name[1] == 'e') {
 		set_user = *argv++;
 		opt |= OPT_u;
 	}

 	// envuidgid?
 	if (ENABLE_ENVUIDGID && applet_name[0] == 'e' && applet_name[3] == 'u') {
 		env_user = *argv++;
 		opt |= OPT_U;
 	}

 	// we must have PROG [ARGS]
 	if (!*argv)
 		bb_show_usage();

 	// set limits
 	if (opt & OPT_d) {
 #ifdef RLIMIT_DATA
 		limit(RLIMIT_DATA, limitd);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"DATA");
 #endif
 	}
 	if (opt & OPT_s) {
 #ifdef RLIMIT_STACK
 		limit(RLIMIT_STACK, limits);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"STACK");
 #endif
 	}
 	if (opt & OPT_l) {
 #ifdef RLIMIT_MEMLOCK
 		limit(RLIMIT_MEMLOCK, limitl);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"MEMLOCK");
 #endif
 	}
 	if (opt & OPT_a) {
 #ifdef RLIMIT_VMEM
 		limit(RLIMIT_VMEM, limita);
 #else
 #ifdef RLIMIT_AS
 		limit(RLIMIT_AS, limita);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"VMEM");
 #endif
 #endif
 	}
 	if (opt & OPT_o) {
 #ifdef RLIMIT_NOFILE
 		limit(RLIMIT_NOFILE, limito);
 #else
 #ifdef RLIMIT_OFILE
 		limit(RLIMIT_OFILE, limito);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"NOFILE");
 #endif
 #endif
 	}
 	if (opt & OPT_p) {
 #ifdef RLIMIT_NPROC
 		limit(RLIMIT_NPROC, limitp);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"NPROC");
 #endif
 	}
 	if (opt & OPT_f) {
 #ifdef RLIMIT_FSIZE
 		limit(RLIMIT_FSIZE, limitf);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"FSIZE");
 #endif
 	}
 	if (opt & OPT_c) {
 #ifdef RLIMIT_CORE
 		limit(RLIMIT_CORE, limitc);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"CORE");
 #endif
 	}
 	if (opt & OPT_r) {
 #ifdef RLIMIT_RSS
 		limit(RLIMIT_RSS, limitr);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"RSS");
 #endif
 	}
 	if (opt & OPT_t) {
 #ifdef RLIMIT_CPU
 		limit(RLIMIT_CPU, limitt);
 #else
 		if (opt & OPT_v)
 			bb_error_msg("system does not support RLIMIT_%s",
 				"CPU");
 #endif
 	}

 	if (opt & OPT_P)
 		setsid();

 	if (opt & OPT_e)
 		edir(env_dir);

 	// FIXME: chrooted jail must have /etc/passwd if we move this after chroot!
 	// OTOH chroot fails for non-roots!
 	// SOLUTION: cache uid/gid before chroot, apply uid/gid after
 	if (opt & OPT_U) {
 		xget_uidgid(&ugid, env_user);
 		xsetenv("GID", utoa(ugid.gid));
 		xsetenv("UID", utoa(ugid.uid));
 	}

 	if (opt & OPT_u) {
 		xget_uidgid(&ugid, set_user);
 	}

 	if (opt & OPT_root) {
 		xchdir(root);
 		xchroot(".");
 	}

 	if (opt & OPT_u) {
 		if (setgroups(1, &ugid.gid) == -1)
 			bb_perror_msg_and_die("setgroups");
 		xsetgid(ugid.gid);
 		xsetuid(ugid.uid);
 	}

 	if (opt & OPT_n) {
 		errno = 0;
 		if (nice(xatoi(nicestr)) == -1)
 			bb_perror_msg_and_die("nice");
 	}

 	if (opt & OPT_0)
 		close(STDIN_FILENO);
 	if (opt & OPT_1)
 		close(STDOUT_FILENO);
 	if (opt & OPT_2)
 		close(STDERR_FILENO);

 	BB_EXECVP_or_die(argv);
 }
	/*
	Copyright (c) 2001-2006, Gerrit Pape
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are met:

	1. Redistributions of source code must retain the above copyright notice,
	this list of conditions and the following disclaimer.
	2. Redistributions in binary form must reproduce the above copyright
	notice, this list of conditions and the following disclaimer in the
	documentation and/or other materials provided with the distribution.
	3. The name of the author may not be used to endorse or promote products
	derived from this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
	EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	/* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */
	/* Dependencies on runit_lib.c removed */

	#include "libbb.h"

	/*
	Five applets here: chpst, envdir, envuidgid, setuidgid, softlimit.

	Only softlimit and chpst are taking options:

	# common
	-o N Limit number of open files per process
	-p N Limit number of processes per uid
	-m BYTES Same as -d BYTES -s BYTES -l BYTES [-a BYTES]
	-d BYTES Limit data segment
	-f BYTES Limit output file sizes
	-c BYTES Limit core file size
	# softlimit
	-a BYTES Limit total size of all segments
	-s BYTES Limit stack segment
	-l BYTES Limit locked memory size
	-r BYTES Limit resident set size
	-t N Limit CPU time
	# chpst
	-u USER[:GRP] Set uid and gid
	-U USER[:GRP] Set $UID and $GID in environment
	-e DIR Set environment variables as specified by files in DIR
	-/ DIR Chroot to DIR
	-n NICE Add NICE to nice value
	-v Verbose
	-P Create new process group
	-0 -1 -2 Close fd 0,1,2

	Even though we accept all these options for both softlimit and chpst,
	they are not to be advertised on their help texts.
	We have enough problems with feature creep in other people's
	software, don't want to add our own.

	envdir, envuidgid, setuidgid take no options, but they reuse code which
	handles -e, -U and -u.
	*/

	enum {
	OPT_a = (1 << 0) * ENABLE_SOFTLIMIT,
	OPT_c = (1 << 1) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_d = (1 << 2) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_f = (1 << 3) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_l = (1 << 4) * ENABLE_SOFTLIMIT,
	OPT_m = (1 << 5) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_o = (1 << 6) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_p = (1 << 7) * (ENABLE_SOFTLIMIT \|\| ENABLE_CHPST),
	OPT_r = (1 << 8) * ENABLE_SOFTLIMIT,
	OPT_s = (1 << 9) * ENABLE_SOFTLIMIT,
	OPT_t = (1 << 10) * ENABLE_SOFTLIMIT,
	OPT_u = (1 << 11) * (ENABLE_CHPST \|\| ENABLE_SETUIDGID),
	OPT_U = (1 << 12) * (ENABLE_CHPST \|\| ENABLE_ENVUIDGID),
	OPT_e = (1 << 13) * (ENABLE_CHPST \|\| ENABLE_ENVDIR),
	OPT_root = (1 << 14) * ENABLE_CHPST,
	OPT_n = (1 << 15) * ENABLE_CHPST,
	OPT_v = (1 << 16) * ENABLE_CHPST,
	OPT_P = (1 << 17) * ENABLE_CHPST,
	OPT_0 = (1 << 18) * ENABLE_CHPST,
	OPT_1 = (1 << 19) * ENABLE_CHPST,
	OPT_2 = (1 << 20) * ENABLE_CHPST,
	};

	/* TODO: use recursive_action? */
	static NOINLINE void edir(const char *directory_name)
	{
	int wdir;
	DIR *dir;
	struct dirent *d;
	int fd;

	wdir = xopen(".", O_RDONLY \| O_NDELAY);
	xchdir(directory_name);
	dir = xopendir(".");
	for (;;) {
	char buf[256];
	char *tail;
	int size;

	errno = 0;
	d = readdir(dir);
	if (!d) {
	if (errno)
	bb_perror_msg_and_die("readdir %s",
	directory_name);
	break;
	}
	if (d->d_name[0] == '.')
	continue;
	fd = open(d->d_name, O_RDONLY \| O_NDELAY);
	if (fd < 0) {
	if ((errno == EISDIR) && directory_name) {
	if (option_mask32 & OPT_v)
	bb_perror_msg("warning: %s/%s is a directory",
	directory_name, d->d_name);
	continue;
	}
	bb_perror_msg_and_die("open %s/%s",
	directory_name, d->d_name);
	}
	size = full_read(fd, buf, sizeof(buf)-1);
	close(fd);
	if (size < 0)
	bb_perror_msg_and_die("read %s/%s",
	directory_name, d->d_name);
	if (size == 0) {
	unsetenv(d->d_name);
	continue;
	}
	buf[size] = '\n';
	tail = strchr(buf, '\n');
	/* skip trailing whitespace */
	while (1) {
	*tail = '\0';
	tail--;
	if (tail < buf \|\| !isspace(*tail))
	break;
	}
	xsetenv(d->d_name, buf);
	}
	closedir(dir);
	if (fchdir(wdir) == -1)
	bb_perror_msg_and_die("fchdir");
	close(wdir);
	}

	static void limit(int what, long l)
	{
	struct rlimit r;

	/* Never fails under Linux (except if you pass it bad arguments) */
	getrlimit(what, &r);
	if ((l < 0) \|\| (l > r.rlim_max))
	r.rlim_cur = r.rlim_max;
	else
	r.rlim_cur = l;
	if (setrlimit(what, &r) == -1)
	bb_perror_msg_and_die("setrlimit");
	}

	int chpst_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int chpst_main(int argc UNUSED_PARAM, char **argv)
	{
	struct bb_uidgid_t ugid;
	char set_user = set_user; / for compiler */
	char *env_user = env_user;
	char *env_dir = env_dir;
	char *root;
	char *nicestr;
	unsigned limita;
	unsigned limitc;
	unsigned limitd;
	unsigned limitf;
	unsigned limitl;
	unsigned limitm;
	unsigned limito;
	unsigned limitp;
	unsigned limitr;
	unsigned limits;
	unsigned limitt;
	unsigned opt;

	if ((ENABLE_CHPST && applet_name[0] == 'c')
	\|\| (ENABLE_SOFTLIMIT && applet_name[1] == 'o')
	) {
	// FIXME: can we live with int-sized limits?
	// can we live with 40000 days?
	// if yes -> getopt converts strings to numbers for us
	opt_complementary = "-1:a+:c+:d+:f+:l+:m+:o+:p+:r+:s+:t+";
	opt = getopt32(argv, "+a:c:d:f:l:m:o:p:r:s:t:u:U:e:"
	IF_CHPST("/:n:vP012"),
	&limita, &limitc, &limitd, &limitf, &limitl,
	&limitm, &limito, &limitp, &limitr, &limits, &limitt,
	&set_user, &env_user, &env_dir
	IF_CHPST(, &root, &nicestr));
	argv += optind;
	if (opt & OPT_m) { // -m means -asld
	limita = limits = limitl = limitd = limitm;
	opt \|= (OPT_s \| OPT_l \| OPT_a \| OPT_d);
	}
	} else {
	option_mask32 = opt = 0;
	argv++;
	if (!*argv)
	bb_show_usage();
	}

	// envdir?
	if (ENABLE_ENVDIR && applet_name[3] == 'd') {
	env_dir = *argv++;
	opt \|= OPT_e;
	}

	// setuidgid?
	if (ENABLE_SETUIDGID && applet_name[1] == 'e') {
	set_user = *argv++;
	opt \|= OPT_u;
	}

	// envuidgid?
	if (ENABLE_ENVUIDGID && applet_name[0] == 'e' && applet_name[3] == 'u') {
	env_user = *argv++;
	opt \|= OPT_U;
	}

	// we must have PROG [ARGS]
	if (!*argv)
	bb_show_usage();

	// set limits
	if (opt & OPT_d) {
	#ifdef RLIMIT_DATA
	limit(RLIMIT_DATA, limitd);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"DATA");
	#endif
	}
	if (opt & OPT_s) {
	#ifdef RLIMIT_STACK
	limit(RLIMIT_STACK, limits);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"STACK");
	#endif
	}
	if (opt & OPT_l) {
	#ifdef RLIMIT_MEMLOCK
	limit(RLIMIT_MEMLOCK, limitl);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"MEMLOCK");
	#endif
	}
	if (opt & OPT_a) {
	#ifdef RLIMIT_VMEM
	limit(RLIMIT_VMEM, limita);
	#else
	#ifdef RLIMIT_AS
	limit(RLIMIT_AS, limita);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"VMEM");
	#endif
	#endif
	}
	if (opt & OPT_o) {
	#ifdef RLIMIT_NOFILE
	limit(RLIMIT_NOFILE, limito);
	#else
	#ifdef RLIMIT_OFILE
	limit(RLIMIT_OFILE, limito);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"NOFILE");
	#endif
	#endif
	}
	if (opt & OPT_p) {
	#ifdef RLIMIT_NPROC
	limit(RLIMIT_NPROC, limitp);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"NPROC");
	#endif
	}
	if (opt & OPT_f) {
	#ifdef RLIMIT_FSIZE
	limit(RLIMIT_FSIZE, limitf);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"FSIZE");
	#endif
	}
	if (opt & OPT_c) {
	#ifdef RLIMIT_CORE
	limit(RLIMIT_CORE, limitc);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"CORE");
	#endif
	}
	if (opt & OPT_r) {
	#ifdef RLIMIT_RSS
	limit(RLIMIT_RSS, limitr);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"RSS");
	#endif
	}
	if (opt & OPT_t) {
	#ifdef RLIMIT_CPU
	limit(RLIMIT_CPU, limitt);
	#else
	if (opt & OPT_v)
	bb_error_msg("system does not support RLIMIT_%s",
	"CPU");
	#endif
	}

	if (opt & OPT_P)
	setsid();

	if (opt & OPT_e)
	edir(env_dir);

	// FIXME: chrooted jail must have /etc/passwd if we move this after chroot!
	// OTOH chroot fails for non-roots!
	// SOLUTION: cache uid/gid before chroot, apply uid/gid after
	if (opt & OPT_U) {
	xget_uidgid(&ugid, env_user);
	xsetenv("GID", utoa(ugid.gid));
	xsetenv("UID", utoa(ugid.uid));
	}

	if (opt & OPT_u) {
	xget_uidgid(&ugid, set_user);
	}

	if (opt & OPT_root) {
	xchdir(root);
	xchroot(".");
	}

	if (opt & OPT_u) {
	if (setgroups(1, &ugid.gid) == -1)
	bb_perror_msg_and_die("setgroups");
	xsetgid(ugid.gid);
	xsetuid(ugid.uid);
	}

	if (opt & OPT_n) {
	errno = 0;
	if (nice(xatoi(nicestr)) == -1)
	bb_perror_msg_and_die("nice");
	}

	if (opt & OPT_0)
	close(STDIN_FILENO);
	if (opt & OPT_1)
	close(STDOUT_FILENO);
	if (opt & OPT_2)
	close(STDERR_FILENO);

	BB_EXECVP_or_die(argv);
	}