1/*
   2 *  linux/kernel/sys.c
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 */
   6
   7#include <linux/export.h>
   8#include <linux/mm.h>
   9#include <linux/utsname.h>
  10#include <linux/mman.h>
  11#include <linux/reboot.h>
  12#include <linux/prctl.h>
  13#include <linux/highuid.h>
  14#include <linux/fs.h>
  15#include <linux/kmod.h>
  16#include <linux/perf_event.h>
  17#include <linux/resource.h>
  18#include <linux/kernel.h>
  19#include <linux/kexec.h>
  20#include <linux/workqueue.h>
  21#include <linux/capability.h>
  22#include <linux/device.h>
  23#include <linux/key.h>
  24#include <linux/times.h>
  25#include <linux/posix-timers.h>
  26#include <linux/security.h>
  27#include <linux/dcookies.h>
  28#include <linux/suspend.h>
  29#include <linux/tty.h>
  30#include <linux/signal.h>
  31#include <linux/cn_proc.h>
  32#include <linux/getcpu.h>
  33#include <linux/task_io_accounting_ops.h>
  34#include <linux/seccomp.h>
  35#include <linux/cpu.h>
  36#include <linux/personality.h>
  37#include <linux/ptrace.h>
  38#include <linux/fs_struct.h>
  39#include <linux/file.h>
  40#include <linux/mount.h>
  41#include <linux/gfp.h>
  42#include <linux/syscore_ops.h>
  43#include <linux/version.h>
  44#include <linux/ctype.h>
  45
  46#include <linux/compat.h>
  47#include <linux/syscalls.h>
  48#include <linux/kprobes.h>
  49#include <linux/user_namespace.h>
  50
  51#include <linux/kmsg_dump.h>
  52/* Move somewhere else to avoid recompiling? */
  53#include <generated/utsrelease.h>
  54
  55#include <asm/uaccess.h>
  56#include <asm/io.h>
  57#include <asm/unistd.h>
  58
  59#ifndef SET_UNALIGN_CTL
  60# define SET_UNALIGN_CTL(a,b)	(-EINVAL)
  61#endif
  62#ifndef GET_UNALIGN_CTL
  63# define GET_UNALIGN_CTL(a,b)	(-EINVAL)
  64#endif
  65#ifndef SET_FPEMU_CTL
  66# define SET_FPEMU_CTL(a,b)	(-EINVAL)
  67#endif
  68#ifndef GET_FPEMU_CTL
  69# define GET_FPEMU_CTL(a,b)	(-EINVAL)
  70#endif
  71#ifndef SET_FPEXC_CTL
  72# define SET_FPEXC_CTL(a,b)	(-EINVAL)
  73#endif
  74#ifndef GET_FPEXC_CTL
  75# define GET_FPEXC_CTL(a,b)	(-EINVAL)
  76#endif
  77#ifndef GET_ENDIAN
  78# define GET_ENDIAN(a,b)	(-EINVAL)
  79#endif
  80#ifndef SET_ENDIAN
  81# define SET_ENDIAN(a,b)	(-EINVAL)
  82#endif
  83#ifndef GET_TSC_CTL
  84# define GET_TSC_CTL(a)		(-EINVAL)
  85#endif
  86#ifndef SET_TSC_CTL
  87# define SET_TSC_CTL(a)		(-EINVAL)
  88#endif
  89
  90/*
  91 * this is where the system-wide overflow UID and GID are defined, for
  92 * architectures that now have 32-bit UID/GID but didn't in the past
  93 */
  94
  95int overflowuid = DEFAULT_OVERFLOWUID;
  96int overflowgid = DEFAULT_OVERFLOWGID;
  97
 
  98EXPORT_SYMBOL(overflowuid);
  99EXPORT_SYMBOL(overflowgid);
 
 100
 101/*
 102 * the same as above, but for filesystems which can only store a 16-bit
 103 * UID and GID. as such, this is needed on all architectures
 104 */
 105
 106int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 107int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 108
 109EXPORT_SYMBOL(fs_overflowuid);
 110EXPORT_SYMBOL(fs_overflowgid);
 111
 112/*
 113 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 114 */
 115
 116int C_A_D = 1;
 117struct pid *cad_pid;
 118EXPORT_SYMBOL(cad_pid);
 119
 120/*
 121 * If set, this is used for preparing the system to power off.
 122 */
 123
 124void (*pm_power_off_prepare)(void);
 125
 126/*
 127 * Returns true if current's euid is same as p's uid or euid,
 128 * or has CAP_SYS_NICE to p's user_ns.
 129 *
 130 * Called with rcu_read_lock, creds are safe
 131 */
 132static bool set_one_prio_perm(struct task_struct *p)
 133{
 134	const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 135
 136	if (uid_eq(pcred->uid,  cred->euid) ||
 137	    uid_eq(pcred->euid, cred->euid))
 
 138		return true;
 139	if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
 140		return true;
 141	return false;
 142}
 143
 144/*
 145 * set the priority of a task
 146 * - the caller must hold the RCU read lock
 147 */
 148static int set_one_prio(struct task_struct *p, int niceval, int error)
 149{
 150	int no_nice;
 151
 152	if (!set_one_prio_perm(p)) {
 153		error = -EPERM;
 154		goto out;
 155	}
 156	if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 157		error = -EACCES;
 158		goto out;
 159	}
 160	no_nice = security_task_setnice(p, niceval);
 161	if (no_nice) {
 162		error = no_nice;
 163		goto out;
 164	}
 165	if (error == -ESRCH)
 166		error = 0;
 167	set_user_nice(p, niceval);
 168out:
 169	return error;
 170}
 171
 172SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 173{
 174	struct task_struct *g, *p;
 175	struct user_struct *user;
 176	const struct cred *cred = current_cred();
 177	int error = -EINVAL;
 178	struct pid *pgrp;
 179	kuid_t uid;
 180
 181	if (which > PRIO_USER || which < PRIO_PROCESS)
 182		goto out;
 183
 184	/* normalize: avoid signed division (rounding problems) */
 185	error = -ESRCH;
 186	if (niceval < -20)
 187		niceval = -20;
 188	if (niceval > 19)
 189		niceval = 19;
 190
 191	rcu_read_lock();
 192	read_lock(&tasklist_lock);
 193	switch (which) {
 194		case PRIO_PROCESS:
 195			if (who)
 196				p = find_task_by_vpid(who);
 197			else
 198				p = current;
 199			if (p)
 200				error = set_one_prio(p, niceval, error);
 201			break;
 202		case PRIO_PGRP:
 203			if (who)
 204				pgrp = find_vpid(who);
 205			else
 206				pgrp = task_pgrp(current);
 207			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 208				error = set_one_prio(p, niceval, error);
 209			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 210			break;
 211		case PRIO_USER:
 212			uid = make_kuid(cred->user_ns, who);
 213			user = cred->user;
 214			if (!who)
 215				uid = cred->uid;
 216			else if (!uid_eq(uid, cred->uid) &&
 217				 !(user = find_user(uid)))
 218				goto out_unlock;	/* No processes for this user */
 219
 220			do_each_thread(g, p) {
 221				if (uid_eq(task_uid(p), uid))
 222					error = set_one_prio(p, niceval, error);
 223			} while_each_thread(g, p);
 224			if (!uid_eq(uid, cred->uid))
 225				free_uid(user);		/* For find_user() */
 226			break;
 227	}
 228out_unlock:
 229	read_unlock(&tasklist_lock);
 230	rcu_read_unlock();
 231out:
 232	return error;
 233}
 234
 235/*
 236 * Ugh. To avoid negative return values, "getpriority()" will
 237 * not return the normal nice-value, but a negated value that
 238 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 239 * to stay compatible.
 240 */
 241SYSCALL_DEFINE2(getpriority, int, which, int, who)
 242{
 243	struct task_struct *g, *p;
 244	struct user_struct *user;
 245	const struct cred *cred = current_cred();
 246	long niceval, retval = -ESRCH;
 247	struct pid *pgrp;
 248	kuid_t uid;
 249
 250	if (which > PRIO_USER || which < PRIO_PROCESS)
 251		return -EINVAL;
 252
 253	rcu_read_lock();
 254	read_lock(&tasklist_lock);
 255	switch (which) {
 256		case PRIO_PROCESS:
 257			if (who)
 258				p = find_task_by_vpid(who);
 259			else
 260				p = current;
 261			if (p) {
 262				niceval = 20 - task_nice(p);
 263				if (niceval > retval)
 264					retval = niceval;
 265			}
 266			break;
 267		case PRIO_PGRP:
 268			if (who)
 269				pgrp = find_vpid(who);
 270			else
 271				pgrp = task_pgrp(current);
 272			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 273				niceval = 20 - task_nice(p);
 274				if (niceval > retval)
 275					retval = niceval;
 276			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 277			break;
 278		case PRIO_USER:
 279			uid = make_kuid(cred->user_ns, who);
 280			user = cred->user;
 281			if (!who)
 282				uid = cred->uid;
 283			else if (!uid_eq(uid, cred->uid) &&
 284				 !(user = find_user(uid)))
 285				goto out_unlock;	/* No processes for this user */
 286
 287			do_each_thread(g, p) {
 288				if (uid_eq(task_uid(p), uid)) {
 289					niceval = 20 - task_nice(p);
 290					if (niceval > retval)
 291						retval = niceval;
 292				}
 293			} while_each_thread(g, p);
 294			if (!uid_eq(uid, cred->uid))
 295				free_uid(user);		/* for find_user() */
 296			break;
 297	}
 298out_unlock:
 299	read_unlock(&tasklist_lock);
 300	rcu_read_unlock();
 301
 302	return retval;
 303}
 304
 305/**
 306 *	emergency_restart - reboot the system
 307 *
 308 *	Without shutting down any hardware or taking any locks
 309 *	reboot the system.  This is called when we know we are in
 310 *	trouble so this is our best effort to reboot.  This is
 311 *	safe to call in interrupt context.
 312 */
 313void emergency_restart(void)
 314{
 315	kmsg_dump(KMSG_DUMP_EMERG);
 316	machine_emergency_restart();
 317}
 318EXPORT_SYMBOL_GPL(emergency_restart);
 319
 320void kernel_restart_prepare(char *cmd)
 321{
 322	blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 323	system_state = SYSTEM_RESTART;
 324	usermodehelper_disable();
 325	device_shutdown();
 326	syscore_shutdown();
 327}
 328
 329/**
 330 *	register_reboot_notifier - Register function to be called at reboot time
 331 *	@nb: Info about notifier function to be called
 332 *
 333 *	Registers a function with the list of functions
 334 *	to be called at reboot time.
 335 *
 336 *	Currently always returns zero, as blocking_notifier_chain_register()
 337 *	always returns zero.
 338 */
 339int register_reboot_notifier(struct notifier_block *nb)
 340{
 341	return blocking_notifier_chain_register(&reboot_notifier_list, nb);
 342}
 343EXPORT_SYMBOL(register_reboot_notifier);
 344
 345/**
 346 *	unregister_reboot_notifier - Unregister previously registered reboot notifier
 347 *	@nb: Hook to be unregistered
 348 *
 349 *	Unregisters a previously registered reboot
 350 *	notifier function.
 351 *
 352 *	Returns zero on success, or %-ENOENT on failure.
 353 */
 354int unregister_reboot_notifier(struct notifier_block *nb)
 355{
 356	return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
 357}
 358EXPORT_SYMBOL(unregister_reboot_notifier);
 359
 360/**
 361 *	kernel_restart - reboot the system
 362 *	@cmd: pointer to buffer containing command to execute for restart
 363 *		or %NULL
 364 *
 365 *	Shutdown everything and perform a clean reboot.
 366 *	This is not safe to call in interrupt context.
 367 */
 368void kernel_restart(char *cmd)
 369{
 370	kernel_restart_prepare(cmd);
 371	if (!cmd)
 372		printk(KERN_EMERG "Restarting system.\n");
 373	else
 374		printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 375	kmsg_dump(KMSG_DUMP_RESTART);
 376	machine_restart(cmd);
 377}
 378EXPORT_SYMBOL_GPL(kernel_restart);
 379
 380static void kernel_shutdown_prepare(enum system_states state)
 381{
 382	blocking_notifier_call_chain(&reboot_notifier_list,
 383		(state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 384	system_state = state;
 385	usermodehelper_disable();
 386	device_shutdown();
 387}
 388/**
 389 *	kernel_halt - halt the system
 390 *
 391 *	Shutdown everything and perform a clean system halt.
 392 */
 393void kernel_halt(void)
 394{
 395	kernel_shutdown_prepare(SYSTEM_HALT);
 396	syscore_shutdown();
 397	printk(KERN_EMERG "System halted.\n");
 398	kmsg_dump(KMSG_DUMP_HALT);
 399	machine_halt();
 400}
 401
 402EXPORT_SYMBOL_GPL(kernel_halt);
 403
 404/**
 405 *	kernel_power_off - power_off the system
 406 *
 407 *	Shutdown everything and perform a clean system power_off.
 408 */
 409void kernel_power_off(void)
 410{
 411	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 412	if (pm_power_off_prepare)
 413		pm_power_off_prepare();
 414	disable_nonboot_cpus();
 415	syscore_shutdown();
 416	printk(KERN_EMERG "Power down.\n");
 417	kmsg_dump(KMSG_DUMP_POWEROFF);
 418	machine_power_off();
 419}
 420EXPORT_SYMBOL_GPL(kernel_power_off);
 421
 422static DEFINE_MUTEX(reboot_mutex);
 423
 424/*
 425 * Reboot system call: for obvious reasons only root may call it,
 426 * and even root needs to set up some magic numbers in the registers
 427 * so that some mistake won't make this reboot the whole machine.
 428 * You can also set the meaning of the ctrl-alt-del-key here.
 429 *
 430 * reboot doesn't sync: do that yourself before calling this.
 431 */
 432SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 433		void __user *, arg)
 434{
 435	char buffer[256];
 436	int ret = 0;
 437
 438	/* We only trust the superuser with rebooting the system. */
 439	if (!capable(CAP_SYS_BOOT))
 440		return -EPERM;
 441
 442	/* For safety, we require "magic" arguments. */
 443	if (magic1 != LINUX_REBOOT_MAGIC1 ||
 444	    (magic2 != LINUX_REBOOT_MAGIC2 &&
 445	                magic2 != LINUX_REBOOT_MAGIC2A &&
 446			magic2 != LINUX_REBOOT_MAGIC2B &&
 447	                magic2 != LINUX_REBOOT_MAGIC2C))
 448		return -EINVAL;
 449
 450	/*
 451	 * If pid namespaces are enabled and the current task is in a child
 452	 * pid_namespace, the command is handled by reboot_pid_ns() which will
 453	 * call do_exit().
 454	 */
 455	ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
 456	if (ret)
 457		return ret;
 458
 459	/* Instead of trying to make the power_off code look like
 460	 * halt when pm_power_off is not set do it the easy way.
 461	 */
 462	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 463		cmd = LINUX_REBOOT_CMD_HALT;
 464
 465	mutex_lock(&reboot_mutex);
 466	switch (cmd) {
 467	case LINUX_REBOOT_CMD_RESTART:
 468		kernel_restart(NULL);
 469		break;
 470
 471	case LINUX_REBOOT_CMD_CAD_ON:
 472		C_A_D = 1;
 473		break;
 474
 475	case LINUX_REBOOT_CMD_CAD_OFF:
 476		C_A_D = 0;
 477		break;
 478
 479	case LINUX_REBOOT_CMD_HALT:
 480		kernel_halt();
 481		do_exit(0);
 482		panic("cannot halt");
 483
 484	case LINUX_REBOOT_CMD_POWER_OFF:
 485		kernel_power_off();
 486		do_exit(0);
 487		break;
 488
 489	case LINUX_REBOOT_CMD_RESTART2:
 490		if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 491			ret = -EFAULT;
 492			break;
 493		}
 494		buffer[sizeof(buffer) - 1] = '\0';
 495
 496		kernel_restart(buffer);
 497		break;
 498
 499#ifdef CONFIG_KEXEC
 500	case LINUX_REBOOT_CMD_KEXEC:
 501		ret = kernel_kexec();
 502		break;
 503#endif
 504
 505#ifdef CONFIG_HIBERNATION
 506	case LINUX_REBOOT_CMD_SW_SUSPEND:
 507		ret = hibernate();
 508		break;
 509#endif
 510
 511	default:
 512		ret = -EINVAL;
 513		break;
 514	}
 515	mutex_unlock(&reboot_mutex);
 516	return ret;
 517}
 518
 519static void deferred_cad(struct work_struct *dummy)
 520{
 521	kernel_restart(NULL);
 522}
 523
 524/*
 525 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 526 * As it's called within an interrupt, it may NOT sync: the only choice
 527 * is whether to reboot at once, or just ignore the ctrl-alt-del.
 528 */
 529void ctrl_alt_del(void)
 530{
 531	static DECLARE_WORK(cad_work, deferred_cad);
 532
 533	if (C_A_D)
 534		schedule_work(&cad_work);
 535	else
 536		kill_cad_pid(SIGINT, 1);
 537}
 538	
 539/*
 540 * Unprivileged users may change the real gid to the effective gid
 541 * or vice versa.  (BSD-style)
 542 *
 543 * If you set the real gid at all, or set the effective gid to a value not
 544 * equal to the real gid, then the saved gid is set to the new effective gid.
 545 *
 546 * This makes it possible for a setgid program to completely drop its
 547 * privileges, which is often a useful assertion to make when you are doing
 548 * a security audit over a program.
 549 *
 550 * The general idea is that a program which uses just setregid() will be
 551 * 100% compatible with BSD.  A program which uses just setgid() will be
 552 * 100% compatible with POSIX with saved IDs. 
 553 *
 554 * SMP: There are not races, the GIDs are checked only by filesystem
 555 *      operations (as far as semantic preservation is concerned).
 556 */
 557SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 558{
 559	struct user_namespace *ns = current_user_ns();
 560	const struct cred *old;
 561	struct cred *new;
 562	int retval;
 563	kgid_t krgid, kegid;
 564
 565	krgid = make_kgid(ns, rgid);
 566	kegid = make_kgid(ns, egid);
 567
 568	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 569		return -EINVAL;
 570	if ((egid != (gid_t) -1) && !gid_valid(kegid))
 571		return -EINVAL;
 572
 573	new = prepare_creds();
 574	if (!new)
 575		return -ENOMEM;
 576	old = current_cred();
 577
 578	retval = -EPERM;
 579	if (rgid != (gid_t) -1) {
 580		if (gid_eq(old->gid, krgid) ||
 581		    gid_eq(old->egid, krgid) ||
 582		    nsown_capable(CAP_SETGID))
 583			new->gid = krgid;
 584		else
 585			goto error;
 586	}
 587	if (egid != (gid_t) -1) {
 588		if (gid_eq(old->gid, kegid) ||
 589		    gid_eq(old->egid, kegid) ||
 590		    gid_eq(old->sgid, kegid) ||
 591		    nsown_capable(CAP_SETGID))
 592			new->egid = kegid;
 593		else
 594			goto error;
 595	}
 596
 597	if (rgid != (gid_t) -1 ||
 598	    (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 599		new->sgid = new->egid;
 600	new->fsgid = new->egid;
 601
 602	return commit_creds(new);
 603
 604error:
 605	abort_creds(new);
 606	return retval;
 607}
 608
 609/*
 610 * setgid() is implemented like SysV w/ SAVED_IDS 
 611 *
 612 * SMP: Same implicit races as above.
 613 */
 614SYSCALL_DEFINE1(setgid, gid_t, gid)
 615{
 616	struct user_namespace *ns = current_user_ns();
 617	const struct cred *old;
 618	struct cred *new;
 619	int retval;
 620	kgid_t kgid;
 621
 622	kgid = make_kgid(ns, gid);
 623	if (!gid_valid(kgid))
 624		return -EINVAL;
 625
 626	new = prepare_creds();
 627	if (!new)
 628		return -ENOMEM;
 629	old = current_cred();
 630
 631	retval = -EPERM;
 632	if (nsown_capable(CAP_SETGID))
 633		new->gid = new->egid = new->sgid = new->fsgid = kgid;
 634	else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 635		new->egid = new->fsgid = kgid;
 636	else
 637		goto error;
 638
 639	return commit_creds(new);
 640
 641error:
 642	abort_creds(new);
 643	return retval;
 644}
 645
 646/*
 647 * change the user struct in a credentials set to match the new UID
 648 */
 649static int set_user(struct cred *new)
 650{
 651	struct user_struct *new_user;
 652
 653	new_user = alloc_uid(new->uid);
 654	if (!new_user)
 655		return -EAGAIN;
 656
 657	/*
 658	 * We don't fail in case of NPROC limit excess here because too many
 659	 * poorly written programs don't check set*uid() return code, assuming
 660	 * it never fails if called by root.  We may still enforce NPROC limit
 661	 * for programs doing set*uid()+execve() by harmlessly deferring the
 662	 * failure to the execve() stage.
 663	 */
 664	if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 665			new_user != INIT_USER)
 666		current->flags |= PF_NPROC_EXCEEDED;
 667	else
 668		current->flags &= ~PF_NPROC_EXCEEDED;
 669
 670	free_uid(new->user);
 671	new->user = new_user;
 672	return 0;
 673}
 674
 675/*
 676 * Unprivileged users may change the real uid to the effective uid
 677 * or vice versa.  (BSD-style)
 678 *
 679 * If you set the real uid at all, or set the effective uid to a value not
 680 * equal to the real uid, then the saved uid is set to the new effective uid.
 681 *
 682 * This makes it possible for a setuid program to completely drop its
 683 * privileges, which is often a useful assertion to make when you are doing
 684 * a security audit over a program.
 685 *
 686 * The general idea is that a program which uses just setreuid() will be
 687 * 100% compatible with BSD.  A program which uses just setuid() will be
 688 * 100% compatible with POSIX with saved IDs. 
 689 */
 690SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 691{
 692	struct user_namespace *ns = current_user_ns();
 693	const struct cred *old;
 694	struct cred *new;
 695	int retval;
 696	kuid_t kruid, keuid;
 697
 698	kruid = make_kuid(ns, ruid);
 699	keuid = make_kuid(ns, euid);
 700
 701	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 702		return -EINVAL;
 703	if ((euid != (uid_t) -1) && !uid_valid(keuid))
 704		return -EINVAL;
 705
 706	new = prepare_creds();
 707	if (!new)
 708		return -ENOMEM;
 709	old = current_cred();
 710
 711	retval = -EPERM;
 712	if (ruid != (uid_t) -1) {
 713		new->uid = kruid;
 714		if (!uid_eq(old->uid, kruid) &&
 715		    !uid_eq(old->euid, kruid) &&
 716		    !nsown_capable(CAP_SETUID))
 717			goto error;
 718	}
 719
 720	if (euid != (uid_t) -1) {
 721		new->euid = keuid;
 722		if (!uid_eq(old->uid, keuid) &&
 723		    !uid_eq(old->euid, keuid) &&
 724		    !uid_eq(old->suid, keuid) &&
 725		    !nsown_capable(CAP_SETUID))
 726			goto error;
 727	}
 728
 729	if (!uid_eq(new->uid, old->uid)) {
 730		retval = set_user(new);
 731		if (retval < 0)
 732			goto error;
 733	}
 734	if (ruid != (uid_t) -1 ||
 735	    (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 736		new->suid = new->euid;
 737	new->fsuid = new->euid;
 738
 739	retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 740	if (retval < 0)
 741		goto error;
 742
 743	return commit_creds(new);
 744
 745error:
 746	abort_creds(new);
 747	return retval;
 748}
 749		
 750/*
 751 * setuid() is implemented like SysV with SAVED_IDS 
 752 * 
 753 * Note that SAVED_ID's is deficient in that a setuid root program
 754 * like sendmail, for example, cannot set its uid to be a normal 
 755 * user and then switch back, because if you're root, setuid() sets
 756 * the saved uid too.  If you don't like this, blame the bright people
 757 * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 758 * will allow a root program to temporarily drop privileges and be able to
 759 * regain them by swapping the real and effective uid.  
 760 */
 761SYSCALL_DEFINE1(setuid, uid_t, uid)
 762{
 763	struct user_namespace *ns = current_user_ns();
 764	const struct cred *old;
 765	struct cred *new;
 766	int retval;
 767	kuid_t kuid;
 768
 769	kuid = make_kuid(ns, uid);
 770	if (!uid_valid(kuid))
 771		return -EINVAL;
 772
 773	new = prepare_creds();
 774	if (!new)
 775		return -ENOMEM;
 776	old = current_cred();
 777
 778	retval = -EPERM;
 779	if (nsown_capable(CAP_SETUID)) {
 780		new->suid = new->uid = kuid;
 781		if (!uid_eq(kuid, old->uid)) {
 782			retval = set_user(new);
 783			if (retval < 0)
 784				goto error;
 785		}
 786	} else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 787		goto error;
 788	}
 789
 790	new->fsuid = new->euid = kuid;
 791
 792	retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 793	if (retval < 0)
 794		goto error;
 795
 796	return commit_creds(new);
 797
 798error:
 799	abort_creds(new);
 800	return retval;
 801}
 802
 803
 804/*
 805 * This function implements a generic ability to update ruid, euid,
 806 * and suid.  This allows you to implement the 4.4 compatible seteuid().
 807 */
 808SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 809{
 810	struct user_namespace *ns = current_user_ns();
 811	const struct cred *old;
 812	struct cred *new;
 813	int retval;
 814	kuid_t kruid, keuid, ksuid;
 815
 816	kruid = make_kuid(ns, ruid);
 817	keuid = make_kuid(ns, euid);
 818	ksuid = make_kuid(ns, suid);
 819
 820	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 821		return -EINVAL;
 822
 823	if ((euid != (uid_t) -1) && !uid_valid(keuid))
 824		return -EINVAL;
 825
 826	if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 827		return -EINVAL;
 828
 829	new = prepare_creds();
 830	if (!new)
 831		return -ENOMEM;
 832
 833	old = current_cred();
 834
 835	retval = -EPERM;
 836	if (!nsown_capable(CAP_SETUID)) {
 837		if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 838		    !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 839			goto error;
 840		if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 841		    !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 842			goto error;
 843		if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 844		    !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 845			goto error;
 846	}
 847
 848	if (ruid != (uid_t) -1) {
 849		new->uid = kruid;
 850		if (!uid_eq(kruid, old->uid)) {
 851			retval = set_user(new);
 852			if (retval < 0)
 853				goto error;
 854		}
 855	}
 856	if (euid != (uid_t) -1)
 857		new->euid = keuid;
 858	if (suid != (uid_t) -1)
 859		new->suid = ksuid;
 860	new->fsuid = new->euid;
 861
 862	retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 863	if (retval < 0)
 864		goto error;
 865
 866	return commit_creds(new);
 867
 868error:
 869	abort_creds(new);
 870	return retval;
 871}
 872
 873SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 874{
 875	const struct cred *cred = current_cred();
 876	int retval;
 877	uid_t ruid, euid, suid;
 878
 879	ruid = from_kuid_munged(cred->user_ns, cred->uid);
 880	euid = from_kuid_munged(cred->user_ns, cred->euid);
 881	suid = from_kuid_munged(cred->user_ns, cred->suid);
 882
 883	if (!(retval   = put_user(ruid, ruidp)) &&
 884	    !(retval   = put_user(euid, euidp)))
 885		retval = put_user(suid, suidp);
 886
 887	return retval;
 888}
 889
 890/*
 891 * Same as above, but for rgid, egid, sgid.
 892 */
 893SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 894{
 895	struct user_namespace *ns = current_user_ns();
 896	const struct cred *old;
 897	struct cred *new;
 898	int retval;
 899	kgid_t krgid, kegid, ksgid;
 900
 901	krgid = make_kgid(ns, rgid);
 902	kegid = make_kgid(ns, egid);
 903	ksgid = make_kgid(ns, sgid);
 904
 905	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 906		return -EINVAL;
 907	if ((egid != (gid_t) -1) && !gid_valid(kegid))
 908		return -EINVAL;
 909	if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 910		return -EINVAL;
 911
 912	new = prepare_creds();
 913	if (!new)
 914		return -ENOMEM;
 915	old = current_cred();
 916
 917	retval = -EPERM;
 918	if (!nsown_capable(CAP_SETGID)) {
 919		if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 920		    !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 921			goto error;
 922		if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 923		    !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 924			goto error;
 925		if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 926		    !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 927			goto error;
 928	}
 929
 930	if (rgid != (gid_t) -1)
 931		new->gid = krgid;
 932	if (egid != (gid_t) -1)
 933		new->egid = kegid;
 934	if (sgid != (gid_t) -1)
 935		new->sgid = ksgid;
 936	new->fsgid = new->egid;
 937
 938	return commit_creds(new);
 939
 940error:
 941	abort_creds(new);
 942	return retval;
 943}
 944
 945SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 946{
 947	const struct cred *cred = current_cred();
 948	int retval;
 949	gid_t rgid, egid, sgid;
 950
 951	rgid = from_kgid_munged(cred->user_ns, cred->gid);
 952	egid = from_kgid_munged(cred->user_ns, cred->egid);
 953	sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 954
 955	if (!(retval   = put_user(rgid, rgidp)) &&
 956	    !(retval   = put_user(egid, egidp)))
 957		retval = put_user(sgid, sgidp);
 958
 959	return retval;
 960}
 961
 962
 963/*
 964 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 965 * is used for "access()" and for the NFS daemon (letting nfsd stay at
 966 * whatever uid it wants to). It normally shadows "euid", except when
 967 * explicitly set by setfsuid() or for access..
 968 */
 969SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 970{
 971	const struct cred *old;
 972	struct cred *new;
 973	uid_t old_fsuid;
 974	kuid_t kuid;
 975
 976	old = current_cred();
 977	old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 978
 979	kuid = make_kuid(old->user_ns, uid);
 980	if (!uid_valid(kuid))
 981		return old_fsuid;
 982
 983	new = prepare_creds();
 984	if (!new)
 985		return old_fsuid;
 
 
 986
 987	if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 988	    uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 989	    nsown_capable(CAP_SETUID)) {
 990		if (!uid_eq(kuid, old->fsuid)) {
 991			new->fsuid = kuid;
 992			if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 993				goto change_okay;
 994		}
 995	}
 996
 997	abort_creds(new);
 998	return old_fsuid;
 999
1000change_okay:
1001	commit_creds(new);
1002	return old_fsuid;
1003}
1004
1005/*
1006 * Samma på svenska..
1007 */
1008SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1009{
1010	const struct cred *old;
1011	struct cred *new;
1012	gid_t old_fsgid;
1013	kgid_t kgid;
1014
1015	old = current_cred();
1016	old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1017
1018	kgid = make_kgid(old->user_ns, gid);
1019	if (!gid_valid(kgid))
1020		return old_fsgid;
1021
1022	new = prepare_creds();
1023	if (!new)
1024		return old_fsgid;
 
 
1025
1026	if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
1027	    gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1028	    nsown_capable(CAP_SETGID)) {
1029		if (!gid_eq(kgid, old->fsgid)) {
1030			new->fsgid = kgid;
1031			goto change_okay;
1032		}
1033	}
1034
1035	abort_creds(new);
1036	return old_fsgid;
1037
1038change_okay:
1039	commit_creds(new);
1040	return old_fsgid;
1041}
1042
1043void do_sys_times(struct tms *tms)
1044{
1045	cputime_t tgutime, tgstime, cutime, cstime;
1046
1047	spin_lock_irq(&current->sighand->siglock);
1048	thread_group_times(current, &tgutime, &tgstime);
1049	cutime = current->signal->cutime;
1050	cstime = current->signal->cstime;
1051	spin_unlock_irq(&current->sighand->siglock);
1052	tms->tms_utime = cputime_to_clock_t(tgutime);
1053	tms->tms_stime = cputime_to_clock_t(tgstime);
1054	tms->tms_cutime = cputime_to_clock_t(cutime);
1055	tms->tms_cstime = cputime_to_clock_t(cstime);
1056}
1057
1058SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1059{
1060	if (tbuf) {
1061		struct tms tmp;
1062
1063		do_sys_times(&tmp);
1064		if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1065			return -EFAULT;
1066	}
1067	force_successful_syscall_return();
1068	return (long) jiffies_64_to_clock_t(get_jiffies_64());
1069}
1070
1071/*
1072 * This needs some heavy checking ...
1073 * I just haven't the stomach for it. I also don't fully
1074 * understand sessions/pgrp etc. Let somebody who does explain it.
1075 *
1076 * OK, I think I have the protection semantics right.... this is really
1077 * only important on a multi-user system anyway, to make sure one user
1078 * can't send a signal to a process owned by another.  -TYT, 12/12/91
1079 *
1080 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1081 * LBT 04.03.94
1082 */
1083SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1084{
1085	struct task_struct *p;
1086	struct task_struct *group_leader = current->group_leader;
1087	struct pid *pgrp;
1088	int err;
1089
1090	if (!pid)
1091		pid = task_pid_vnr(group_leader);
1092	if (!pgid)
1093		pgid = pid;
1094	if (pgid < 0)
1095		return -EINVAL;
1096	rcu_read_lock();
1097
1098	/* From this point forward we keep holding onto the tasklist lock
1099	 * so that our parent does not change from under us. -DaveM
1100	 */
1101	write_lock_irq(&tasklist_lock);
1102
1103	err = -ESRCH;
1104	p = find_task_by_vpid(pid);
1105	if (!p)
1106		goto out;
1107
1108	err = -EINVAL;
1109	if (!thread_group_leader(p))
1110		goto out;
1111
1112	if (same_thread_group(p->real_parent, group_leader)) {
1113		err = -EPERM;
1114		if (task_session(p) != task_session(group_leader))
1115			goto out;
1116		err = -EACCES;
1117		if (p->did_exec)
1118			goto out;
1119	} else {
1120		err = -ESRCH;
1121		if (p != group_leader)
1122			goto out;
1123	}
1124
1125	err = -EPERM;
1126	if (p->signal->leader)
1127		goto out;
1128
1129	pgrp = task_pid(p);
1130	if (pgid != pid) {
1131		struct task_struct *g;
1132
1133		pgrp = find_vpid(pgid);
1134		g = pid_task(pgrp, PIDTYPE_PGID);
1135		if (!g || task_session(g) != task_session(group_leader))
1136			goto out;
1137	}
1138
1139	err = security_task_setpgid(p, pgid);
1140	if (err)
1141		goto out;
1142
1143	if (task_pgrp(p) != pgrp)
1144		change_pid(p, PIDTYPE_PGID, pgrp);
1145
1146	err = 0;
1147out:
1148	/* All paths lead to here, thus we are safe. -DaveM */
1149	write_unlock_irq(&tasklist_lock);
1150	rcu_read_unlock();
1151	return err;
1152}
1153
1154SYSCALL_DEFINE1(getpgid, pid_t, pid)
1155{
1156	struct task_struct *p;
1157	struct pid *grp;
1158	int retval;
1159
1160	rcu_read_lock();
1161	if (!pid)
1162		grp = task_pgrp(current);
1163	else {
1164		retval = -ESRCH;
1165		p = find_task_by_vpid(pid);
1166		if (!p)
1167			goto out;
1168		grp = task_pgrp(p);
1169		if (!grp)
1170			goto out;
1171
1172		retval = security_task_getpgid(p);
1173		if (retval)
1174			goto out;
1175	}
1176	retval = pid_vnr(grp);
1177out:
1178	rcu_read_unlock();
1179	return retval;
1180}
1181
1182#ifdef __ARCH_WANT_SYS_GETPGRP
1183
1184SYSCALL_DEFINE0(getpgrp)
1185{
1186	return sys_getpgid(0);
1187}
1188
1189#endif
1190
1191SYSCALL_DEFINE1(getsid, pid_t, pid)
1192{
1193	struct task_struct *p;
1194	struct pid *sid;
1195	int retval;
1196
1197	rcu_read_lock();
1198	if (!pid)
1199		sid = task_session(current);
1200	else {
1201		retval = -ESRCH;
1202		p = find_task_by_vpid(pid);
1203		if (!p)
1204			goto out;
1205		sid = task_session(p);
1206		if (!sid)
1207			goto out;
1208
1209		retval = security_task_getsid(p);
1210		if (retval)
1211			goto out;
1212	}
1213	retval = pid_vnr(sid);
1214out:
1215	rcu_read_unlock();
1216	return retval;
1217}
1218
1219SYSCALL_DEFINE0(setsid)
1220{
1221	struct task_struct *group_leader = current->group_leader;
1222	struct pid *sid = task_pid(group_leader);
1223	pid_t session = pid_vnr(sid);
1224	int err = -EPERM;
1225
1226	write_lock_irq(&tasklist_lock);
1227	/* Fail if I am already a session leader */
1228	if (group_leader->signal->leader)
1229		goto out;
1230
1231	/* Fail if a process group id already exists that equals the
1232	 * proposed session id.
1233	 */
1234	if (pid_task(sid, PIDTYPE_PGID))
1235		goto out;
1236
1237	group_leader->signal->leader = 1;
1238	__set_special_pids(sid);
1239
1240	proc_clear_tty(group_leader);
1241
1242	err = session;
1243out:
1244	write_unlock_irq(&tasklist_lock);
1245	if (err > 0) {
1246		proc_sid_connector(group_leader);
1247		sched_autogroup_create_attach(group_leader);
1248	}
1249	return err;
1250}
1251
1252DECLARE_RWSEM(uts_sem);
1253
1254#ifdef COMPAT_UTS_MACHINE
1255#define override_architecture(name) \
1256	(personality(current->personality) == PER_LINUX32 && \
1257	 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1258		      sizeof(COMPAT_UTS_MACHINE)))
1259#else
1260#define override_architecture(name)	0
1261#endif
1262
1263/*
1264 * Work around broken programs that cannot handle "Linux 3.0".
1265 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1266 */
1267static int override_release(char __user *release, int len)
1268{
1269	int ret = 0;
1270	char buf[65];
1271
1272	if (current->personality & UNAME26) {
1273		char *rest = UTS_RELEASE;
1274		int ndots = 0;
1275		unsigned v;
1276
1277		while (*rest) {
1278			if (*rest == '.' && ++ndots >= 3)
1279				break;
1280			if (!isdigit(*rest) && *rest != '.')
1281				break;
1282			rest++;
1283		}
1284		v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1285		snprintf(buf, len, "2.6.%u%s", v, rest);
1286		ret = copy_to_user(release, buf, len);
1287	}
1288	return ret;
1289}
1290
1291SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1292{
1293	int errno = 0;
1294
1295	down_read(&uts_sem);
1296	if (copy_to_user(name, utsname(), sizeof *name))
1297		errno = -EFAULT;
1298	up_read(&uts_sem);
1299
1300	if (!errno && override_release(name->release, sizeof(name->release)))
1301		errno = -EFAULT;
1302	if (!errno && override_architecture(name))
1303		errno = -EFAULT;
1304	return errno;
1305}
1306
1307#ifdef __ARCH_WANT_SYS_OLD_UNAME
1308/*
1309 * Old cruft
1310 */
1311SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1312{
1313	int error = 0;
1314
1315	if (!name)
1316		return -EFAULT;
1317
1318	down_read(&uts_sem);
1319	if (copy_to_user(name, utsname(), sizeof(*name)))
1320		error = -EFAULT;
1321	up_read(&uts_sem);
1322
1323	if (!error && override_release(name->release, sizeof(name->release)))
1324		error = -EFAULT;
1325	if (!error && override_architecture(name))
1326		error = -EFAULT;
1327	return error;
1328}
1329
1330SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1331{
1332	int error;
1333
1334	if (!name)
1335		return -EFAULT;
1336	if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1337		return -EFAULT;
1338
1339	down_read(&uts_sem);
1340	error = __copy_to_user(&name->sysname, &utsname()->sysname,
1341			       __OLD_UTS_LEN);
1342	error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1343	error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1344				__OLD_UTS_LEN);
1345	error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1346	error |= __copy_to_user(&name->release, &utsname()->release,
1347				__OLD_UTS_LEN);
1348	error |= __put_user(0, name->release + __OLD_UTS_LEN);
1349	error |= __copy_to_user(&name->version, &utsname()->version,
1350				__OLD_UTS_LEN);
1351	error |= __put_user(0, name->version + __OLD_UTS_LEN);
1352	error |= __copy_to_user(&name->machine, &utsname()->machine,
1353				__OLD_UTS_LEN);
1354	error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1355	up_read(&uts_sem);
1356
1357	if (!error && override_architecture(name))
1358		error = -EFAULT;
1359	if (!error && override_release(name->release, sizeof(name->release)))
1360		error = -EFAULT;
1361	return error ? -EFAULT : 0;
1362}
1363#endif
1364
1365SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1366{
1367	int errno;
1368	char tmp[__NEW_UTS_LEN];
1369
1370	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1371		return -EPERM;
1372
1373	if (len < 0 || len > __NEW_UTS_LEN)
1374		return -EINVAL;
1375	down_write(&uts_sem);
1376	errno = -EFAULT;
1377	if (!copy_from_user(tmp, name, len)) {
1378		struct new_utsname *u = utsname();
1379
1380		memcpy(u->nodename, tmp, len);
1381		memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1382		errno = 0;
1383		uts_proc_notify(UTS_PROC_HOSTNAME);
1384	}
1385	up_write(&uts_sem);
1386	return errno;
1387}
1388
1389#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1390
1391SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1392{
1393	int i, errno;
1394	struct new_utsname *u;
1395
1396	if (len < 0)
1397		return -EINVAL;
1398	down_read(&uts_sem);
1399	u = utsname();
1400	i = 1 + strlen(u->nodename);
1401	if (i > len)
1402		i = len;
1403	errno = 0;
1404	if (copy_to_user(name, u->nodename, i))
1405		errno = -EFAULT;
1406	up_read(&uts_sem);
1407	return errno;
1408}
1409
1410#endif
1411
1412/*
1413 * Only setdomainname; getdomainname can be implemented by calling
1414 * uname()
1415 */
1416SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1417{
1418	int errno;
1419	char tmp[__NEW_UTS_LEN];
1420
1421	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1422		return -EPERM;
1423	if (len < 0 || len > __NEW_UTS_LEN)
1424		return -EINVAL;
1425
1426	down_write(&uts_sem);
1427	errno = -EFAULT;
1428	if (!copy_from_user(tmp, name, len)) {
1429		struct new_utsname *u = utsname();
1430
1431		memcpy(u->domainname, tmp, len);
1432		memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1433		errno = 0;
1434		uts_proc_notify(UTS_PROC_DOMAINNAME);
1435	}
1436	up_write(&uts_sem);
1437	return errno;
1438}
1439
1440SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1441{
1442	struct rlimit value;
1443	int ret;
1444
1445	ret = do_prlimit(current, resource, NULL, &value);
1446	if (!ret)
1447		ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1448
1449	return ret;
1450}
1451
1452#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1453
1454/*
1455 *	Back compatibility for getrlimit. Needed for some apps.
1456 */
1457 
1458SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1459		struct rlimit __user *, rlim)
1460{
1461	struct rlimit x;
1462	if (resource >= RLIM_NLIMITS)
1463		return -EINVAL;
1464
1465	task_lock(current->group_leader);
1466	x = current->signal->rlim[resource];
1467	task_unlock(current->group_leader);
1468	if (x.rlim_cur > 0x7FFFFFFF)
1469		x.rlim_cur = 0x7FFFFFFF;
1470	if (x.rlim_max > 0x7FFFFFFF)
1471		x.rlim_max = 0x7FFFFFFF;
1472	return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1473}
1474
1475#endif
1476
1477static inline bool rlim64_is_infinity(__u64 rlim64)
1478{
1479#if BITS_PER_LONG < 64
1480	return rlim64 >= ULONG_MAX;
1481#else
1482	return rlim64 == RLIM64_INFINITY;
1483#endif
1484}
1485
1486static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1487{
1488	if (rlim->rlim_cur == RLIM_INFINITY)
1489		rlim64->rlim_cur = RLIM64_INFINITY;
1490	else
1491		rlim64->rlim_cur = rlim->rlim_cur;
1492	if (rlim->rlim_max == RLIM_INFINITY)
1493		rlim64->rlim_max = RLIM64_INFINITY;
1494	else
1495		rlim64->rlim_max = rlim->rlim_max;
1496}
1497
1498static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1499{
1500	if (rlim64_is_infinity(rlim64->rlim_cur))
1501		rlim->rlim_cur = RLIM_INFINITY;
1502	else
1503		rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1504	if (rlim64_is_infinity(rlim64->rlim_max))
1505		rlim->rlim_max = RLIM_INFINITY;
1506	else
1507		rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1508}
1509
1510/* make sure you are allowed to change @tsk limits before calling this */
1511int do_prlimit(struct task_struct *tsk, unsigned int resource,
1512		struct rlimit *new_rlim, struct rlimit *old_rlim)
1513{
1514	struct rlimit *rlim;
1515	int retval = 0;
1516
1517	if (resource >= RLIM_NLIMITS)
1518		return -EINVAL;
1519	if (new_rlim) {
1520		if (new_rlim->rlim_cur > new_rlim->rlim_max)
1521			return -EINVAL;
1522		if (resource == RLIMIT_NOFILE &&
1523				new_rlim->rlim_max > sysctl_nr_open)
1524			return -EPERM;
1525	}
1526
1527	/* protect tsk->signal and tsk->sighand from disappearing */
1528	read_lock(&tasklist_lock);
1529	if (!tsk->sighand) {
1530		retval = -ESRCH;
1531		goto out;
1532	}
1533
1534	rlim = tsk->signal->rlim + resource;
1535	task_lock(tsk->group_leader);
1536	if (new_rlim) {
1537		/* Keep the capable check against init_user_ns until
1538		   cgroups can contain all limits */
1539		if (new_rlim->rlim_max > rlim->rlim_max &&
1540				!capable(CAP_SYS_RESOURCE))
1541			retval = -EPERM;
1542		if (!retval)
1543			retval = security_task_setrlimit(tsk->group_leader,
1544					resource, new_rlim);
1545		if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1546			/*
1547			 * The caller is asking for an immediate RLIMIT_CPU
1548			 * expiry.  But we use the zero value to mean "it was
1549			 * never set".  So let's cheat and make it one second
1550			 * instead
1551			 */
1552			new_rlim->rlim_cur = 1;
1553		}
1554	}
1555	if (!retval) {
1556		if (old_rlim)
1557			*old_rlim = *rlim;
1558		if (new_rlim)
1559			*rlim = *new_rlim;
1560	}
1561	task_unlock(tsk->group_leader);
1562
1563	/*
1564	 * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1565	 * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1566	 * very long-standing error, and fixing it now risks breakage of
1567	 * applications, so we live with it
1568	 */
1569	 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1570			 new_rlim->rlim_cur != RLIM_INFINITY)
1571		update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1572out:
1573	read_unlock(&tasklist_lock);
1574	return retval;
1575}
1576
1577/* rcu lock must be held */
1578static int check_prlimit_permission(struct task_struct *task)
1579{
1580	const struct cred *cred = current_cred(), *tcred;
1581
1582	if (current == task)
1583		return 0;
1584
1585	tcred = __task_cred(task);
1586	if (uid_eq(cred->uid, tcred->euid) &&
1587	    uid_eq(cred->uid, tcred->suid) &&
1588	    uid_eq(cred->uid, tcred->uid)  &&
1589	    gid_eq(cred->gid, tcred->egid) &&
1590	    gid_eq(cred->gid, tcred->sgid) &&
1591	    gid_eq(cred->gid, tcred->gid))
 
1592		return 0;
1593	if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1594		return 0;
1595
1596	return -EPERM;
1597}
1598
1599SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1600		const struct rlimit64 __user *, new_rlim,
1601		struct rlimit64 __user *, old_rlim)
1602{
1603	struct rlimit64 old64, new64;
1604	struct rlimit old, new;
1605	struct task_struct *tsk;
1606	int ret;
1607
1608	if (new_rlim) {
1609		if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1610			return -EFAULT;
1611		rlim64_to_rlim(&new64, &new);
1612	}
1613
1614	rcu_read_lock();
1615	tsk = pid ? find_task_by_vpid(pid) : current;
1616	if (!tsk) {
1617		rcu_read_unlock();
1618		return -ESRCH;
1619	}
1620	ret = check_prlimit_permission(tsk);
1621	if (ret) {
1622		rcu_read_unlock();
1623		return ret;
1624	}
1625	get_task_struct(tsk);
1626	rcu_read_unlock();
1627
1628	ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1629			old_rlim ? &old : NULL);
1630
1631	if (!ret && old_rlim) {
1632		rlim_to_rlim64(&old, &old64);
1633		if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1634			ret = -EFAULT;
1635	}
1636
1637	put_task_struct(tsk);
1638	return ret;
1639}
1640
1641SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1642{
1643	struct rlimit new_rlim;
1644
1645	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1646		return -EFAULT;
1647	return do_prlimit(current, resource, &new_rlim, NULL);
1648}
1649
1650/*
1651 * It would make sense to put struct rusage in the task_struct,
1652 * except that would make the task_struct be *really big*.  After
1653 * task_struct gets moved into malloc'ed memory, it would
1654 * make sense to do this.  It will make moving the rest of the information
1655 * a lot simpler!  (Which we're not doing right now because we're not
1656 * measuring them yet).
1657 *
1658 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1659 * races with threads incrementing their own counters.  But since word
1660 * reads are atomic, we either get new values or old values and we don't
1661 * care which for the sums.  We always take the siglock to protect reading
1662 * the c* fields from p->signal from races with exit.c updating those
1663 * fields when reaping, so a sample either gets all the additions of a
1664 * given child after it's reaped, or none so this sample is before reaping.
1665 *
1666 * Locking:
1667 * We need to take the siglock for CHILDEREN, SELF and BOTH
1668 * for  the cases current multithreaded, non-current single threaded
1669 * non-current multithreaded.  Thread traversal is now safe with
1670 * the siglock held.
1671 * Strictly speaking, we donot need to take the siglock if we are current and
1672 * single threaded,  as no one else can take our signal_struct away, no one
1673 * else can  reap the  children to update signal->c* counters, and no one else
1674 * can race with the signal-> fields. If we do not take any lock, the
1675 * signal-> fields could be read out of order while another thread was just
1676 * exiting. So we should  place a read memory barrier when we avoid the lock.
1677 * On the writer side,  write memory barrier is implied in  __exit_signal
1678 * as __exit_signal releases  the siglock spinlock after updating the signal->
1679 * fields. But we don't do this yet to keep things simple.
1680 *
1681 */
1682
1683static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1684{
1685	r->ru_nvcsw += t->nvcsw;
1686	r->ru_nivcsw += t->nivcsw;
1687	r->ru_minflt += t->min_flt;
1688	r->ru_majflt += t->maj_flt;
1689	r->ru_inblock += task_io_get_inblock(t);
1690	r->ru_oublock += task_io_get_oublock(t);
1691}
1692
1693static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1694{
1695	struct task_struct *t;
1696	unsigned long flags;
1697	cputime_t tgutime, tgstime, utime, stime;
1698	unsigned long maxrss = 0;
1699
1700	memset((char *) r, 0, sizeof *r);
1701	utime = stime = 0;
1702
1703	if (who == RUSAGE_THREAD) {
1704		task_times(current, &utime, &stime);
1705		accumulate_thread_rusage(p, r);
1706		maxrss = p->signal->maxrss;
1707		goto out;
1708	}
1709
1710	if (!lock_task_sighand(p, &flags))
1711		return;
1712
1713	switch (who) {
1714		case RUSAGE_BOTH:
1715		case RUSAGE_CHILDREN:
1716			utime = p->signal->cutime;
1717			stime = p->signal->cstime;
1718			r->ru_nvcsw = p->signal->cnvcsw;
1719			r->ru_nivcsw = p->signal->cnivcsw;
1720			r->ru_minflt = p->signal->cmin_flt;
1721			r->ru_majflt = p->signal->cmaj_flt;
1722			r->ru_inblock = p->signal->cinblock;
1723			r->ru_oublock = p->signal->coublock;
1724			maxrss = p->signal->cmaxrss;
1725
1726			if (who == RUSAGE_CHILDREN)
1727				break;
1728
1729		case RUSAGE_SELF:
1730			thread_group_times(p, &tgutime, &tgstime);
1731			utime += tgutime;
1732			stime += tgstime;
1733			r->ru_nvcsw += p->signal->nvcsw;
1734			r->ru_nivcsw += p->signal->nivcsw;
1735			r->ru_minflt += p->signal->min_flt;
1736			r->ru_majflt += p->signal->maj_flt;
1737			r->ru_inblock += p->signal->inblock;
1738			r->ru_oublock += p->signal->oublock;
1739			if (maxrss < p->signal->maxrss)
1740				maxrss = p->signal->maxrss;
1741			t = p;
1742			do {
1743				accumulate_thread_rusage(t, r);
1744				t = next_thread(t);
1745			} while (t != p);
1746			break;
1747
1748		default:
1749			BUG();
1750	}
1751	unlock_task_sighand(p, &flags);
1752
1753out:
1754	cputime_to_timeval(utime, &r->ru_utime);
1755	cputime_to_timeval(stime, &r->ru_stime);
1756
1757	if (who != RUSAGE_CHILDREN) {
1758		struct mm_struct *mm = get_task_mm(p);
1759		if (mm) {
1760			setmax_mm_hiwater_rss(&maxrss, mm);
1761			mmput(mm);
1762		}
1763	}
1764	r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1765}
1766
1767int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1768{
1769	struct rusage r;
1770	k_getrusage(p, who, &r);
1771	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1772}
1773
1774SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1775{
1776	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1777	    who != RUSAGE_THREAD)
1778		return -EINVAL;
1779	return getrusage(current, who, ru);
1780}
1781
1782SYSCALL_DEFINE1(umask, int, mask)
1783{
1784	mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1785	return mask;
1786}
1787
1788#ifdef CONFIG_CHECKPOINT_RESTORE
1789static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1790{
1791	struct file *exe_file;
1792	struct dentry *dentry;
1793	int err;
1794
1795	exe_file = fget(fd);
1796	if (!exe_file)
1797		return -EBADF;
1798
1799	dentry = exe_file->f_path.dentry;
1800
1801	/*
1802	 * Because the original mm->exe_file points to executable file, make
1803	 * sure that this one is executable as well, to avoid breaking an
1804	 * overall picture.
1805	 */
1806	err = -EACCES;
1807	if (!S_ISREG(dentry->d_inode->i_mode)	||
1808	    exe_file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1809		goto exit;
1810
1811	err = inode_permission(dentry->d_inode, MAY_EXEC);
1812	if (err)
1813		goto exit;
1814
1815	down_write(&mm->mmap_sem);
1816
1817	/*
1818	 * Forbid mm->exe_file change if old file still mapped.
1819	 */
1820	err = -EBUSY;
1821	if (mm->exe_file) {
1822		struct vm_area_struct *vma;
1823
1824		for (vma = mm->mmap; vma; vma = vma->vm_next)
1825			if (vma->vm_file &&
1826			    path_equal(&vma->vm_file->f_path,
1827				       &mm->exe_file->f_path))
1828				goto exit_unlock;
1829	}
1830
1831	/*
1832	 * The symlink can be changed only once, just to disallow arbitrary
1833	 * transitions malicious software might bring in. This means one
1834	 * could make a snapshot over all processes running and monitor
1835	 * /proc/pid/exe changes to notice unusual activity if needed.
1836	 */
1837	err = -EPERM;
1838	if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1839		goto exit_unlock;
1840
1841	err = 0;
1842	set_mm_exe_file(mm, exe_file);
1843exit_unlock:
1844	up_write(&mm->mmap_sem);
1845
1846exit:
1847	fput(exe_file);
1848	return err;
1849}
1850
1851static int prctl_set_mm(int opt, unsigned long addr,
1852			unsigned long arg4, unsigned long arg5)
1853{
1854	unsigned long rlim = rlimit(RLIMIT_DATA);
1855	struct mm_struct *mm = current->mm;
1856	struct vm_area_struct *vma;
1857	int error;
1858
1859	if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1860		return -EINVAL;
1861
1862	if (!capable(CAP_SYS_RESOURCE))
1863		return -EPERM;
1864
1865	if (opt == PR_SET_MM_EXE_FILE)
1866		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1867
1868	if (addr >= TASK_SIZE || addr < mmap_min_addr)
1869		return -EINVAL;
1870
1871	error = -EINVAL;
1872
1873	down_read(&mm->mmap_sem);
1874	vma = find_vma(mm, addr);
1875
1876	switch (opt) {
1877	case PR_SET_MM_START_CODE:
1878		mm->start_code = addr;
1879		break;
1880	case PR_SET_MM_END_CODE:
1881		mm->end_code = addr;
1882		break;
1883	case PR_SET_MM_START_DATA:
1884		mm->start_data = addr;
1885		break;
1886	case PR_SET_MM_END_DATA:
1887		mm->end_data = addr;
1888		break;
1889
1890	case PR_SET_MM_START_BRK:
1891		if (addr <= mm->end_data)
1892			goto out;
1893
1894		if (rlim < RLIM_INFINITY &&
1895		    (mm->brk - addr) +
1896		    (mm->end_data - mm->start_data) > rlim)
1897			goto out;
1898
1899		mm->start_brk = addr;
1900		break;
1901
1902	case PR_SET_MM_BRK:
1903		if (addr <= mm->end_data)
1904			goto out;
1905
1906		if (rlim < RLIM_INFINITY &&
1907		    (addr - mm->start_brk) +
1908		    (mm->end_data - mm->start_data) > rlim)
1909			goto out;
1910
1911		mm->brk = addr;
1912		break;
1913
1914	/*
1915	 * If command line arguments and environment
1916	 * are placed somewhere else on stack, we can
1917	 * set them up here, ARG_START/END to setup
1918	 * command line argumets and ENV_START/END
1919	 * for environment.
1920	 */
1921	case PR_SET_MM_START_STACK:
1922	case PR_SET_MM_ARG_START:
1923	case PR_SET_MM_ARG_END:
1924	case PR_SET_MM_ENV_START:
1925	case PR_SET_MM_ENV_END:
1926		if (!vma) {
1927			error = -EFAULT;
1928			goto out;
1929		}
1930		if (opt == PR_SET_MM_START_STACK)
1931			mm->start_stack = addr;
1932		else if (opt == PR_SET_MM_ARG_START)
1933			mm->arg_start = addr;
1934		else if (opt == PR_SET_MM_ARG_END)
1935			mm->arg_end = addr;
1936		else if (opt == PR_SET_MM_ENV_START)
1937			mm->env_start = addr;
1938		else if (opt == PR_SET_MM_ENV_END)
1939			mm->env_end = addr;
1940		break;
1941
1942	/*
1943	 * This doesn't move auxiliary vector itself
1944	 * since it's pinned to mm_struct, but allow
1945	 * to fill vector with new values. It's up
1946	 * to a caller to provide sane values here
1947	 * otherwise user space tools which use this
1948	 * vector might be unhappy.
1949	 */
1950	case PR_SET_MM_AUXV: {
1951		unsigned long user_auxv[AT_VECTOR_SIZE];
1952
1953		if (arg4 > sizeof(user_auxv))
1954			goto out;
1955		up_read(&mm->mmap_sem);
1956
1957		if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1958			return -EFAULT;
1959
1960		/* Make sure the last entry is always AT_NULL */
1961		user_auxv[AT_VECTOR_SIZE - 2] = 0;
1962		user_auxv[AT_VECTOR_SIZE - 1] = 0;
1963
1964		BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1965
1966		task_lock(current);
1967		memcpy(mm->saved_auxv, user_auxv, arg4);
1968		task_unlock(current);
1969
1970		return 0;
1971	}
1972	default:
1973		goto out;
1974	}
1975
1976	error = 0;
1977out:
1978	up_read(&mm->mmap_sem);
1979	return error;
1980}
1981
1982static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1983{
1984	return put_user(me->clear_child_tid, tid_addr);
1985}
1986
1987#else /* CONFIG_CHECKPOINT_RESTORE */
1988static int prctl_set_mm(int opt, unsigned long addr,
1989			unsigned long arg4, unsigned long arg5)
1990{
1991	return -EINVAL;
1992}
1993static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1994{
1995	return -EINVAL;
1996}
1997#endif
1998
1999SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2000		unsigned long, arg4, unsigned long, arg5)
2001{
2002	struct task_struct *me = current;
2003	unsigned char comm[sizeof(me->comm)];
2004	long error;
2005
2006	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2007	if (error != -ENOSYS)
2008		return error;
2009
2010	error = 0;
2011	switch (option) {
2012		case PR_SET_PDEATHSIG:
2013			if (!valid_signal(arg2)) {
2014				error = -EINVAL;
2015				break;
2016			}
2017			me->pdeath_signal = arg2;
2018			error = 0;
2019			break;
2020		case PR_GET_PDEATHSIG:
2021			error = put_user(me->pdeath_signal, (int __user *)arg2);
2022			break;
2023		case PR_GET_DUMPABLE:
2024			error = get_dumpable(me->mm);
2025			break;
2026		case PR_SET_DUMPABLE:
2027			if (arg2 < 0 || arg2 > 1) {
2028				error = -EINVAL;
2029				break;
2030			}
2031			set_dumpable(me->mm, arg2);
2032			error = 0;
2033			break;
2034
2035		case PR_SET_UNALIGN:
2036			error = SET_UNALIGN_CTL(me, arg2);
2037			break;
2038		case PR_GET_UNALIGN:
2039			error = GET_UNALIGN_CTL(me, arg2);
2040			break;
2041		case PR_SET_FPEMU:
2042			error = SET_FPEMU_CTL(me, arg2);
2043			break;
2044		case PR_GET_FPEMU:
2045			error = GET_FPEMU_CTL(me, arg2);
2046			break;
2047		case PR_SET_FPEXC:
2048			error = SET_FPEXC_CTL(me, arg2);
2049			break;
2050		case PR_GET_FPEXC:
2051			error = GET_FPEXC_CTL(me, arg2);
2052			break;
2053		case PR_GET_TIMING:
2054			error = PR_TIMING_STATISTICAL;
2055			break;
2056		case PR_SET_TIMING:
2057			if (arg2 != PR_TIMING_STATISTICAL)
2058				error = -EINVAL;
2059			else
2060				error = 0;
2061			break;
2062
2063		case PR_SET_NAME:
2064			comm[sizeof(me->comm)-1] = 0;
2065			if (strncpy_from_user(comm, (char __user *)arg2,
2066					      sizeof(me->comm) - 1) < 0)
2067				return -EFAULT;
2068			set_task_comm(me, comm);
2069			proc_comm_connector(me);
2070			return 0;
2071		case PR_GET_NAME:
2072			get_task_comm(comm, me);
2073			if (copy_to_user((char __user *)arg2, comm,
2074					 sizeof(comm)))
2075				return -EFAULT;
2076			return 0;
2077		case PR_GET_ENDIAN:
2078			error = GET_ENDIAN(me, arg2);
2079			break;
2080		case PR_SET_ENDIAN:
2081			error = SET_ENDIAN(me, arg2);
2082			break;
2083
2084		case PR_GET_SECCOMP:
2085			error = prctl_get_seccomp();
2086			break;
2087		case PR_SET_SECCOMP:
2088			error = prctl_set_seccomp(arg2, (char __user *)arg3);
2089			break;
2090		case PR_GET_TSC:
2091			error = GET_TSC_CTL(arg2);
2092			break;
2093		case PR_SET_TSC:
2094			error = SET_TSC_CTL(arg2);
2095			break;
2096		case PR_TASK_PERF_EVENTS_DISABLE:
2097			error = perf_event_task_disable();
2098			break;
2099		case PR_TASK_PERF_EVENTS_ENABLE:
2100			error = perf_event_task_enable();
2101			break;
2102		case PR_GET_TIMERSLACK:
2103			error = current->timer_slack_ns;
2104			break;
2105		case PR_SET_TIMERSLACK:
2106			if (arg2 <= 0)
2107				current->timer_slack_ns =
2108					current->default_timer_slack_ns;
2109			else
2110				current->timer_slack_ns = arg2;
2111			error = 0;
2112			break;
2113		case PR_MCE_KILL:
2114			if (arg4 | arg5)
2115				return -EINVAL;
2116			switch (arg2) {
2117			case PR_MCE_KILL_CLEAR:
2118				if (arg3 != 0)
2119					return -EINVAL;
2120				current->flags &= ~PF_MCE_PROCESS;
2121				break;
2122			case PR_MCE_KILL_SET:
2123				current->flags |= PF_MCE_PROCESS;
2124				if (arg3 == PR_MCE_KILL_EARLY)
2125					current->flags |= PF_MCE_EARLY;
2126				else if (arg3 == PR_MCE_KILL_LATE)
2127					current->flags &= ~PF_MCE_EARLY;
2128				else if (arg3 == PR_MCE_KILL_DEFAULT)
2129					current->flags &=
2130						~(PF_MCE_EARLY|PF_MCE_PROCESS);
2131				else
2132					return -EINVAL;
2133				break;
2134			default:
2135				return -EINVAL;
2136			}
2137			error = 0;
2138			break;
2139		case PR_MCE_KILL_GET:
2140			if (arg2 | arg3 | arg4 | arg5)
2141				return -EINVAL;
2142			if (current->flags & PF_MCE_PROCESS)
2143				error = (current->flags & PF_MCE_EARLY) ?
2144					PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2145			else
2146				error = PR_MCE_KILL_DEFAULT;
2147			break;
2148		case PR_SET_MM:
2149			error = prctl_set_mm(arg2, arg3, arg4, arg5);
2150			break;
2151		case PR_GET_TID_ADDRESS:
2152			error = prctl_get_tid_address(me, (int __user **)arg2);
2153			break;
2154		case PR_SET_CHILD_SUBREAPER:
2155			me->signal->is_child_subreaper = !!arg2;
2156			error = 0;
2157			break;
2158		case PR_GET_CHILD_SUBREAPER:
2159			error = put_user(me->signal->is_child_subreaper,
2160					 (int __user *) arg2);
2161			break;
2162		case PR_SET_NO_NEW_PRIVS:
2163			if (arg2 != 1 || arg3 || arg4 || arg5)
2164				return -EINVAL;
2165
2166			current->no_new_privs = 1;
2167			break;
2168		case PR_GET_NO_NEW_PRIVS:
2169			if (arg2 || arg3 || arg4 || arg5)
2170				return -EINVAL;
2171			return current->no_new_privs ? 1 : 0;
2172		default:
2173			error = -EINVAL;
2174			break;
2175	}
2176	return error;
2177}
2178
2179SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2180		struct getcpu_cache __user *, unused)
2181{
2182	int err = 0;
2183	int cpu = raw_smp_processor_id();
2184	if (cpup)
2185		err |= put_user(cpu, cpup);
2186	if (nodep)
2187		err |= put_user(cpu_to_node(cpu), nodep);
2188	return err ? -EFAULT : 0;
2189}
2190
2191char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2192
2193static void argv_cleanup(struct subprocess_info *info)
2194{
2195	argv_free(info->argv);
2196}
2197
2198/**
2199 * orderly_poweroff - Trigger an orderly system poweroff
2200 * @force: force poweroff if command execution fails
2201 *
2202 * This may be called from any context to trigger a system shutdown.
2203 * If the orderly shutdown fails, it will force an immediate shutdown.
2204 */
2205int orderly_poweroff(bool force)
2206{
2207	int argc;
2208	char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2209	static char *envp[] = {
2210		"HOME=/",
2211		"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2212		NULL
2213	};
2214	int ret = -ENOMEM;
 
2215
2216	if (argv == NULL) {
2217		printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2218		       __func__, poweroff_cmd);
2219		goto out;
2220	}
2221
2222	ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
2223				      NULL, argv_cleanup, NULL);
2224out:
2225	if (likely(!ret))
2226		return 0;
2227
2228	if (ret == -ENOMEM)
2229		argv_free(argv);
 
 
 
 
 
 
2230
2231	if (force) {
 
2232		printk(KERN_WARNING "Failed to start orderly shutdown: "
2233		       "forcing the issue\n");
2234
2235		/* I guess this should try to kick off some daemon to
2236		   sync and poweroff asap.  Or not even bother syncing
2237		   if we're doing an emergency shutdown? */
2238		emergency_sync();
2239		kernel_power_off();
2240	}
2241
2242	return ret;
2243}
2244EXPORT_SYMBOL_GPL(orderly_poweroff);