minijail0.c - aosp/platform/external/minijail - Git at Google

 /* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include <dlfcn.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include "libminijail.h"
 #include "libsyscalls.h"

 #include "elfparse.h"
 #include "util.h"

 static void set_user(struct minijail *j, const char *arg)
 {
 	char *end = NULL;
 	int uid = strtod(arg, &end);
 	if (!*end && *arg) {
 		minijail_change_uid(j, uid);
 		return;
 	}

 	if (minijail_change_user(j, arg)) {
 		fprintf(stderr, "Bad user: '%s'\n", arg);
 		exit(1);
 	}
 }

 static void set_group(struct minijail *j, const char *arg)
 {
 	char *end = NULL;
 	int gid = strtod(arg, &end);
 	if (!*end && *arg) {
 		minijail_change_gid(j, gid);
 		return;
 	}

 	if (minijail_change_group(j, arg)) {
 		fprintf(stderr, "Bad group: '%s'\n", arg);
 		exit(1);
 	}
 }

 static void use_caps(struct minijail *j, const char *arg)
 {
 	uint64_t caps;
 	char *end = NULL;
 	caps = strtoull(arg, &end, 16);
 	if (*end) {
 		fprintf(stderr, "Invalid cap set: '%s'\n", arg);
 		exit(1);
 	}
 	minijail_use_caps(j, caps);
 }

 static void add_binding(struct minijail *j, char *arg)
 {
 	char *src = strtok(arg, ",");
 	char *dest = strtok(NULL, ",");
 	char *flags = strtok(NULL, ",");
 	if (!src || !dest) {
 		fprintf(stderr, "Bad binding: %s %s\n", src, dest);
 		exit(1);
 	}
 	if (minijail_bind(j, src, dest, flags ? atoi(flags) : 0)) {
 		fprintf(stderr, "minijail_bind failed.\n");
 		exit(1);
 	}
 }

 static void add_mount(struct minijail *j, char *arg)
 {
 	char *src = strtok(arg, ",");
 	char *dest = strtok(NULL, ",");
 	char *type = strtok(NULL, ",");
 	char *flags = strtok(NULL, ",");
 	if (!src || !dest || !type) {
 		fprintf(stderr, "Bad mount: %s %s %s\n", src, dest, type);
 		exit(1);
 	}
 	if (minijail_mount(j, src, dest, type,
 			   flags ? strtoul(flags, NULL, 16) : 0)) {
 		fprintf(stderr, "minijail_mount failed.\n");
 		exit(1);
 	}
 }

 static void usage(const char *progn)
 {
 	size_t i;

 	printf("Usage: %s [-GhiIlnprstUv]\n"
 	       "  [-b <src>,<dest>[,<writeable>]] [-f <file>]"
 	       " [-c <caps>] [-C <dir>] [-g <group>] [-u <user>]\n"
 	       "  [-S <file>] [-k <src>,<dest>,<type>[,<flags>]] [-T <type>]\n"
 	       "  [-m \"<uid> <loweruid> <count>[,<uid> <loweruid> <count>]\"]\n"
 	       "  [-M \"<gid> <lowergid> <count>[,<uid> <loweruid> <count>]\"]\n"
 	       "  <program> [args...]\n"
 	       "  -a <table>: Use alternate syscall table <table>.\n"
 	       "  -b:         Bind <src> to <dest> in chroot.\n"
 	       "              Multiple instances allowed.\n"
 	       "  -k:         Mount <src> at <dest> in chroot.\n"
 	       "              Multiple instances allowed, flags are passed to mount(2).\n"
 	       "  -c <caps>:  Restrict caps to <caps>.\n"
 	       "  -C <dir>:   chroot(2) to <dir>.\n"
 	       "              Not compatible with -P.\n"
 	       "  -e[file]:   Enter new network namespace, or existing one if 'file' is provided.\n"
 	       "  -f <file>:  Write the pid of the jailed process to <file>.\n"
 	       "  -G:         Inherit supplementary groups from uid.\n"
 	       "  -g <group>: Change gid to <group>.\n"
 	       "  -h:         Help (this message).\n"
 	       "  -H:         Seccomp filter help message.\n"
 	       "  -i:         Exit immediately after fork (do not act as init).\n"
 	       "              Not compatible with -p.\n"
 	       "  -I:         Run <program> as init (pid 1) inside a new pid namespace (implies -p).\n"
 	       "  -K:         Don't mark all existing mounts as MS_PRIVATE.\n"
 	       "  -l:         Enter new IPC namespace.\n"
 	       "  -L:         Report blocked syscalls to syslog when using seccomp filter.\n"
 	       "              Forces the following syscalls to be allowed:\n"
 	       "                  ", progn);
 	for (i = 0; i < log_syscalls_len; i++)
 		printf("%s ", log_syscalls[i]);

 	printf("\n"
 	       "  -m:         Set the uid mapping of a user namespace (implies -pU).\n"
 	       "              Same arguments as newuidmap(1), multiple mappings should be separated by ',' (comma).\n"
 	       "              Not compatible with -b without the 'writable' option.\n"
 	       "  -M:         Set the gid mapping of a user namespace (implies -pU).\n"
 	       "              Same arguments as newgidmap(1), multiple mappings should be separated by ',' (comma).\n"
 	       "              Not compatible with -b without the 'writable' option.\n"
 	       "  -n:         Set no_new_privs.\n"
 	       "  -p:         Enter new pid namespace (implies -vr).\n"
 	       "  -P <dir>:   pivot_root(2) to <dir> (implies -v).\n"
 	       "              Not compatible with -C.\n"
 	       "  -r:         Remount /proc read-only (implies -v).\n"
 	       "  -s:         Use seccomp.\n"
 	       "  -S <file>:  Set seccomp filter using <file>.\n"
 	       "              E.g., '-S /usr/share/filters/<prog>.$(uname -m)'.\n"
 	       "              Requires -n when not running as root.\n"
 	       "  -t:         Mount tmpfs at /tmp inside chroot.\n"
 	       "  -T <type>:  Don't access <program> before execve(2), assume <type> ELF binary.\n"
 	       "              <type> must be 'static' or 'dynamic'.\n"
 	       "  -u <user>:  Change uid to <user>.\n"
 	       "  -U:         Enter new user namespace (implies -p).\n"
 	       "  -v:         Enter new mount namespace.\n"
 	       "  -V <file>:  Enter specified mount namespace.\n");
 }

 static void seccomp_filter_usage(const char *progn)
 {
 	const struct syscall_entry *entry = syscall_table;
 	printf("Usage: %s -S <policy.file> <program> [args...]\n\n"
 	       "System call names supported:\n", progn);
 	for (; entry->name && entry->nr >= 0; ++entry)
 		printf("  %s [%d]\n", entry->name, entry->nr);
 	printf("\nSee minijail0(5) for example policies.\n");
 }

 static int parse_args(struct minijail *j, int argc, char *argv[],
 		      int *exit_immediately, ElfType *elftype)
 {
 	int opt;
 	int use_seccomp_filter = 0;
 	int binding = 0;
 	int pivot_root = 0, chroot = 0;
 	int mount_ns = 0, skip_remount = 0;
 	const size_t path_max = 4096;
 	const char *filter_path;
 	if (argc > 1 && argv[1][0] != '-')
 		return 1;
 	while ((opt = getopt(argc, argv,
 			     "u:g:sS:c:C:P:b:V:f:m:M:k:a:e::T:vrGhHinplLtIUK"))
 	       != -1) {
 		switch (opt) {
 		case 'u':
 			set_user(j, optarg);
 			break;
 		case 'g':
 			set_group(j, optarg);
 			break;
 		case 'n':
 			minijail_no_new_privs(j);
 			break;
 		case 's':
 			minijail_use_seccomp(j);
 			break;
 		case 'S':
 			minijail_use_seccomp_filter(j);
 			if (strlen(optarg) >= path_max) {
 				fprintf(stderr, "Filter path is too long.\n");
 				exit(1);
 			}
 			filter_path = strndup(optarg, path_max);
 			if (!filter_path) {
 				fprintf(stderr,
 					"Could not strndup(3) filter path.\n");
 				exit(1);
 			}
 			use_seccomp_filter = 1;
 			break;
 		case 'l':
 			minijail_namespace_ipc(j);
 			break;
 		case 'L':
 			minijail_log_seccomp_filter_failures(j);
 			break;
 		case 'b':
 			add_binding(j, optarg);
 			binding = 1;
 			break;
 		case 'c':
 			use_caps(j, optarg);
 			break;
 		case 'C':
 			if (pivot_root) {
 				fprintf(stderr, "Could not set chroot because "
 						"'-P' was specified.\n");
 				exit(1);
 			}
 			if (0 != minijail_enter_chroot(j, optarg)) {
 				fprintf(stderr, "Could not set chroot.\n");
 				exit(1);
 			}
 			chroot = 1;
 			break;
 		case 'k':
 			add_mount(j, optarg);
 			break;
 		case 'K':
 			minijail_skip_remount_private(j);
 			skip_remount = 1;
 			break;
 		case 'P':
 			if (chroot) {
 				fprintf(stderr,
 					"Could not set pivot_root because "
 					"'-C' was specified.\n");
 				exit(1);
 			}
 			if (0 != minijail_enter_pivot_root(j, optarg)) {
 				fprintf(stderr, "Could not set pivot_root.\n");
 				exit(1);
 			}
 			minijail_namespace_vfs(j);
 			pivot_root = 1;
 			break;
 		case 'f':
 			if (0 != minijail_write_pid_file(j, optarg)) {
 				fprintf(stderr,
 					"Could not prepare pid file path.\n");
 				exit(1);
 			}
 			break;
 		case 't':
 			minijail_mount_tmp(j);
 			break;
 		case 'v':
 			minijail_namespace_vfs(j);
 			mount_ns = 1;
 			break;
 		case 'V':
 			minijail_namespace_enter_vfs(j, optarg);
 			break;
 		case 'r':
 			minijail_remount_proc_readonly(j);
 			break;
 		case 'G':
 			minijail_inherit_usergroups(j);
 			break;
 		case 'p':
 			minijail_namespace_pids(j);
 			break;
 		case 'e':
 			if (optarg)
 				minijail_namespace_enter_net(j, optarg);
 			else
 				minijail_namespace_net(j);
 			break;
 		case 'i':
 			*exit_immediately = 1;
 			break;
 		case 'H':
 			seccomp_filter_usage(argv[0]);
 			exit(1);
 		case 'I':
 			minijail_namespace_pids(j);
 			minijail_run_as_init(j);
 			break;
 		case 'U':
 			minijail_namespace_user(j);
 			minijail_namespace_pids(j);
 			break;
 		case 'm':
 			minijail_namespace_user(j);
 			minijail_namespace_pids(j);
 			if (0 != minijail_uidmap(j, optarg)) {
 				fprintf(stderr, "Could not set uidmap.\n");
 				exit(1);
 			}
 			break;
 		case 'M':
 			minijail_namespace_user(j);
 			minijail_namespace_pids(j);
 			if (0 != minijail_gidmap(j, optarg)) {
 				fprintf(stderr, "Could not set gidmap.\n");
 				exit(1);
 			}
 			break;
 		case 'a':
 			if (0 != minijail_use_alt_syscall(j, optarg)) {
 				fprintf(stderr,
 					"Could not set alt-syscall table.\n");
 				exit(1);
 			}
 			break;
 		case 'T':
 			if (!strcmp(optarg, "static"))
 				*elftype = ELFSTATIC;
 			else if (!strcmp(optarg, "dynamic"))
 				*elftype = ELFDYNAMIC;
 			else {
 				fprintf(stderr, "ELF type must be 'static' or "
 						"'dynamic'.\n");
 				exit(1);
 			}
 			break;
 		default:
 			usage(argv[0]);
 			exit(1);
 		}
 		if (optind < argc && argv[optind][0] != '-')
 			break;
 	}

 	/* Only allow bind mounts when entering a chroot or using pivot_root. */
 	if (binding && !(chroot || pivot_root)) {
 		fprintf(stderr, "Can't add bind mounts without chroot or"
 				" pivot_root.\n");
 		exit(1);
 	}

 	/*
 	 * Remounting / as MS_PRIVATE only happens when entering a new mount
 	 * namespace, so skipping it only applies in that case.
 	 */
 	if (skip_remount && !mount_ns) {
 		fprintf(stderr, "Can't skip marking mounts as MS_PRIVATE"
 				" without mount namespaces.\n");
 		exit(1);
 	}

 	/*
 	 * We parse seccomp filters here to make sure we've collected all
 	 * cmdline options.
 	 */
 	if (use_seccomp_filter) {
 		minijail_parse_seccomp_filters(j, filter_path);
 		free((void*)filter_path);
 	}

 	if (argc == optind) {
 		usage(argv[0]);
 		exit(1);
 	}

 	return optind;
 }

 int main(int argc, char *argv[])
 {
 	struct minijail *j = minijail_new();
 	const char *dl_mesg = NULL;
 	int exit_immediately = 0;
 	ElfType elftype = ELFERROR;
 	int consumed = parse_args(j, argc, argv, &exit_immediately, &elftype);
 	argc -= consumed;
 	argv += consumed;

 	if (elftype == ELFERROR) {
 		/*
 		 * -T was not specified.
 		 * Get the path to the program adjusted for changing root.
 		 */
 		char *program_path = minijail_get_original_path(j, argv[0]);

 		/* Check that we can access the target program. */
 		if (access(program_path, X_OK)) {
 			fprintf(stderr,
 				"Target program '%s' is not accessible.\n",
 				argv[0]);
 			return 1;
 		}

 		/* Check if target is statically or dynamically linked. */
 		elftype = get_elf_linkage(program_path);
 		free(program_path);
 	}

 	if (elftype == ELFSTATIC) {
 		/*
 		 * Target binary is statically linked so we cannot use
 		 * libminijailpreload.so.
 		 */
 		minijail_run_no_preload(j, argv[0], argv);
 	} else if (elftype == ELFDYNAMIC) {
 		/*
 		 * Target binary is dynamically linked so we can
 		 * inject libminijailpreload.so into it.
 		 */

 		/* Check that we can dlopen() libminijailpreload.so. */
 		if (!dlopen(PRELOADPATH, RTLD_LAZY | RTLD_LOCAL)) {
 			dl_mesg = dlerror();
 			fprintf(stderr, "dlopen(): %s\n", dl_mesg);
 			return 1;
 		}
 		minijail_run(j, argv[0], argv);
 	} else {
 		fprintf(stderr,
 			"Target program '%s' is not a valid ELF file.\n",
 			argv[0]);
 		return 1;
 	}

 	if (exit_immediately) {
 		info("not running init loop, exiting immediately");
 		return 0;
 	}
 	return minijail_wait(j);
 }
	/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include <dlfcn.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include "libminijail.h"
	#include "libsyscalls.h"

	#include "elfparse.h"
	#include "util.h"

	static void set_user(struct minijail j, const char arg)
	{
	char *end = NULL;
	int uid = strtod(arg, &end);
	if (!end && arg) {
	minijail_change_uid(j, uid);
	return;
	}

	if (minijail_change_user(j, arg)) {
	fprintf(stderr, "Bad user: '%s'\n", arg);
	exit(1);
	}
	}

	static void set_group(struct minijail j, const char arg)
	{
	char *end = NULL;
	int gid = strtod(arg, &end);
	if (!end && arg) {
	minijail_change_gid(j, gid);
	return;
	}

	if (minijail_change_group(j, arg)) {
	fprintf(stderr, "Bad group: '%s'\n", arg);
	exit(1);
	}
	}

	static void use_caps(struct minijail j, const char arg)
	{
	uint64_t caps;
	char *end = NULL;
	caps = strtoull(arg, &end, 16);
	if (*end) {
	fprintf(stderr, "Invalid cap set: '%s'\n", arg);
	exit(1);
	}
	minijail_use_caps(j, caps);
	}

	static void add_binding(struct minijail j, char arg)
	{
	char *src = strtok(arg, ",");
	char *dest = strtok(NULL, ",");
	char *flags = strtok(NULL, ",");
	if (!src \|\| !dest) {
	fprintf(stderr, "Bad binding: %s %s\n", src, dest);
	exit(1);
	}
	if (minijail_bind(j, src, dest, flags ? atoi(flags) : 0)) {
	fprintf(stderr, "minijail_bind failed.\n");
	exit(1);
	}
	}

	static void add_mount(struct minijail j, char arg)
	{
	char *src = strtok(arg, ",");
	char *dest = strtok(NULL, ",");
	char *type = strtok(NULL, ",");
	char *flags = strtok(NULL, ",");
	if (!src \|\| !dest \|\| !type) {
	fprintf(stderr, "Bad mount: %s %s %s\n", src, dest, type);
	exit(1);
	}
	if (minijail_mount(j, src, dest, type,
	flags ? strtoul(flags, NULL, 16) : 0)) {
	fprintf(stderr, "minijail_mount failed.\n");
	exit(1);
	}
	}

	static void usage(const char *progn)
	{
	size_t i;

	printf("Usage: %s [-GhiIlnprstUv]\n"
	" [-b <src>,<dest>[,<writeable>]] [-f <file>]"
	" [-c <caps>] [-C <dir>] [-g <group>] [-u <user>]\n"
	" [-S <file>] [-k <src>,<dest>,<type>[,<flags>]] [-T <type>]\n"
	" [-m \"<uid> <loweruid> <count>[,<uid> <loweruid> <count>]\"]\n"
	" [-M \"<gid> <lowergid> <count>[,<uid> <loweruid> <count>]\"]\n"
	" <program> [args...]\n"
	" -a <table>: Use alternate syscall table <table>.\n"
	" -b: Bind <src> to <dest> in chroot.\n"
	" Multiple instances allowed.\n"
	" -k: Mount <src> at <dest> in chroot.\n"
	" Multiple instances allowed, flags are passed to mount(2).\n"
	" -c <caps>: Restrict caps to <caps>.\n"
	" -C <dir>: chroot(2) to <dir>.\n"
	" Not compatible with -P.\n"
	" -e[file]: Enter new network namespace, or existing one if 'file' is provided.\n"
	" -f <file>: Write the pid of the jailed process to <file>.\n"
	" -G: Inherit supplementary groups from uid.\n"
	" -g <group>: Change gid to <group>.\n"
	" -h: Help (this message).\n"
	" -H: Seccomp filter help message.\n"
	" -i: Exit immediately after fork (do not act as init).\n"
	" Not compatible with -p.\n"
	" -I: Run <program> as init (pid 1) inside a new pid namespace (implies -p).\n"
	" -K: Don't mark all existing mounts as MS_PRIVATE.\n"
	" -l: Enter new IPC namespace.\n"
	" -L: Report blocked syscalls to syslog when using seccomp filter.\n"
	" Forces the following syscalls to be allowed:\n"
	" ", progn);
	for (i = 0; i < log_syscalls_len; i++)
	printf("%s ", log_syscalls[i]);

	printf("\n"
	" -m: Set the uid mapping of a user namespace (implies -pU).\n"
	" Same arguments as newuidmap(1), multiple mappings should be separated by ',' (comma).\n"
	" Not compatible with -b without the 'writable' option.\n"
	" -M: Set the gid mapping of a user namespace (implies -pU).\n"
	" Same arguments as newgidmap(1), multiple mappings should be separated by ',' (comma).\n"
	" Not compatible with -b without the 'writable' option.\n"
	" -n: Set no_new_privs.\n"
	" -p: Enter new pid namespace (implies -vr).\n"
	" -P <dir>: pivot_root(2) to <dir> (implies -v).\n"
	" Not compatible with -C.\n"
	" -r: Remount /proc read-only (implies -v).\n"
	" -s: Use seccomp.\n"
	" -S <file>: Set seccomp filter using <file>.\n"
	" E.g., '-S /usr/share/filters/<prog>.$(uname -m)'.\n"
	" Requires -n when not running as root.\n"
	" -t: Mount tmpfs at /tmp inside chroot.\n"
	" -T <type>: Don't access <program> before execve(2), assume <type> ELF binary.\n"
	" <type> must be 'static' or 'dynamic'.\n"
	" -u <user>: Change uid to <user>.\n"
	" -U: Enter new user namespace (implies -p).\n"
	" -v: Enter new mount namespace.\n"
	" -V <file>: Enter specified mount namespace.\n");
	}

	static void seccomp_filter_usage(const char *progn)
	{
	const struct syscall_entry *entry = syscall_table;
	printf("Usage: %s -S <policy.file> <program> [args...]\n\n"
	"System call names supported:\n", progn);
	for (; entry->name && entry->nr >= 0; ++entry)
	printf(" %s [%d]\n", entry->name, entry->nr);
	printf("\nSee minijail0(5) for example policies.\n");
	}

	static int parse_args(struct minijail j, int argc, char argv[],
	int exit_immediately, ElfType elftype)
	{
	int opt;
	int use_seccomp_filter = 0;
	int binding = 0;
	int pivot_root = 0, chroot = 0;
	int mount_ns = 0, skip_remount = 0;
	const size_t path_max = 4096;
	const char *filter_path;
	if (argc > 1 && argv[1][0] != '-')
	return 1;
	while ((opt = getopt(argc, argv,
	"u:g:sS:c:C:P:b:V:f:m:M:k:a:e::T:vrGhHinplLtIUK"))
	!= -1) {
	switch (opt) {
	case 'u':
	set_user(j, optarg);
	break;
	case 'g':
	set_group(j, optarg);
	break;
	case 'n':
	minijail_no_new_privs(j);
	break;
	case 's':
	minijail_use_seccomp(j);
	break;
	case 'S':
	minijail_use_seccomp_filter(j);
	if (strlen(optarg) >= path_max) {
	fprintf(stderr, "Filter path is too long.\n");
	exit(1);
	}
	filter_path = strndup(optarg, path_max);
	if (!filter_path) {
	fprintf(stderr,
	"Could not strndup(3) filter path.\n");
	exit(1);
	}
	use_seccomp_filter = 1;
	break;
	case 'l':
	minijail_namespace_ipc(j);
	break;
	case 'L':
	minijail_log_seccomp_filter_failures(j);
	break;
	case 'b':
	add_binding(j, optarg);
	binding = 1;
	break;
	case 'c':
	use_caps(j, optarg);
	break;
	case 'C':
	if (pivot_root) {
	fprintf(stderr, "Could not set chroot because "
	"'-P' was specified.\n");
	exit(1);
	}
	if (0 != minijail_enter_chroot(j, optarg)) {
	fprintf(stderr, "Could not set chroot.\n");
	exit(1);
	}
	chroot = 1;
	break;
	case 'k':
	add_mount(j, optarg);
	break;
	case 'K':
	minijail_skip_remount_private(j);
	skip_remount = 1;
	break;
	case 'P':
	if (chroot) {
	fprintf(stderr,
	"Could not set pivot_root because "
	"'-C' was specified.\n");
	exit(1);
	}
	if (0 != minijail_enter_pivot_root(j, optarg)) {
	fprintf(stderr, "Could not set pivot_root.\n");
	exit(1);
	}
	minijail_namespace_vfs(j);
	pivot_root = 1;
	break;
	case 'f':
	if (0 != minijail_write_pid_file(j, optarg)) {
	fprintf(stderr,
	"Could not prepare pid file path.\n");
	exit(1);
	}
	break;
	case 't':
	minijail_mount_tmp(j);
	break;
	case 'v':
	minijail_namespace_vfs(j);
	mount_ns = 1;
	break;
	case 'V':
	minijail_namespace_enter_vfs(j, optarg);
	break;
	case 'r':
	minijail_remount_proc_readonly(j);
	break;
	case 'G':
	minijail_inherit_usergroups(j);
	break;
	case 'p':
	minijail_namespace_pids(j);
	break;
	case 'e':
	if (optarg)
	minijail_namespace_enter_net(j, optarg);
	else
	minijail_namespace_net(j);
	break;
	case 'i':
	*exit_immediately = 1;
	break;
	case 'H':
	seccomp_filter_usage(argv[0]);
	exit(1);
	case 'I':
	minijail_namespace_pids(j);
	minijail_run_as_init(j);
	break;
	case 'U':
	minijail_namespace_user(j);
	minijail_namespace_pids(j);
	break;
	case 'm':
	minijail_namespace_user(j);
	minijail_namespace_pids(j);
	if (0 != minijail_uidmap(j, optarg)) {
	fprintf(stderr, "Could not set uidmap.\n");
	exit(1);
	}
	break;
	case 'M':
	minijail_namespace_user(j);
	minijail_namespace_pids(j);
	if (0 != minijail_gidmap(j, optarg)) {
	fprintf(stderr, "Could not set gidmap.\n");
	exit(1);
	}
	break;
	case 'a':
	if (0 != minijail_use_alt_syscall(j, optarg)) {
	fprintf(stderr,
	"Could not set alt-syscall table.\n");
	exit(1);
	}
	break;
	case 'T':
	if (!strcmp(optarg, "static"))
	*elftype = ELFSTATIC;
	else if (!strcmp(optarg, "dynamic"))
	*elftype = ELFDYNAMIC;
	else {
	fprintf(stderr, "ELF type must be 'static' or "
	"'dynamic'.\n");
	exit(1);
	}
	break;
	default:
	usage(argv[0]);
	exit(1);
	}
	if (optind < argc && argv[optind][0] != '-')
	break;
	}

	/* Only allow bind mounts when entering a chroot or using pivot_root. */
	if (binding && !(chroot \|\| pivot_root)) {
	fprintf(stderr, "Can't add bind mounts without chroot or"
	" pivot_root.\n");
	exit(1);
	}

	/*
	* Remounting / as MS_PRIVATE only happens when entering a new mount
	* namespace, so skipping it only applies in that case.
	*/
	if (skip_remount && !mount_ns) {
	fprintf(stderr, "Can't skip marking mounts as MS_PRIVATE"
	" without mount namespaces.\n");
	exit(1);
	}

	/*
	* We parse seccomp filters here to make sure we've collected all
	* cmdline options.
	*/
	if (use_seccomp_filter) {
	minijail_parse_seccomp_filters(j, filter_path);
	free((void*)filter_path);
	}

	if (argc == optind) {
	usage(argv[0]);
	exit(1);
	}

	return optind;
	}

	int main(int argc, char *argv[])
	{
	struct minijail *j = minijail_new();
	const char *dl_mesg = NULL;
	int exit_immediately = 0;
	ElfType elftype = ELFERROR;
	int consumed = parse_args(j, argc, argv, &exit_immediately, &elftype);
	argc -= consumed;
	argv += consumed;

	if (elftype == ELFERROR) {
	/*
	* -T was not specified.
	* Get the path to the program adjusted for changing root.
	*/
	char *program_path = minijail_get_original_path(j, argv[0]);

	/* Check that we can access the target program. */
	if (access(program_path, X_OK)) {
	fprintf(stderr,
	"Target program '%s' is not accessible.\n",
	argv[0]);
	return 1;
	}

	/* Check if target is statically or dynamically linked. */
	elftype = get_elf_linkage(program_path);
	free(program_path);
	}

	if (elftype == ELFSTATIC) {
	/*
	* Target binary is statically linked so we cannot use
	* libminijailpreload.so.
	*/
	minijail_run_no_preload(j, argv[0], argv);
	} else if (elftype == ELFDYNAMIC) {
	/*
	* Target binary is dynamically linked so we can
	* inject libminijailpreload.so into it.
	*/

	/* Check that we can dlopen() libminijailpreload.so. */
	if (!dlopen(PRELOADPATH, RTLD_LAZY \| RTLD_LOCAL)) {
	dl_mesg = dlerror();
	fprintf(stderr, "dlopen(): %s\n", dl_mesg);
	return 1;
	}
	minijail_run(j, argv[0], argv);
	} else {
	fprintf(stderr,
	"Target program '%s' is not a valid ELF file.\n",
	argv[0]);
	return 1;
	}

	if (exit_immediately) {
	info("not running init loop, exiting immediately");
	return 0;
	}
	return minijail_wait(j);
	}