linux/kernel/sys.c
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   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        disable_nonboot_cpus();
 372        if (!cmd)
 373                printk(KERN_EMERG "Restarting system.\n");
 374        else
 375                printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 376        kmsg_dump(KMSG_DUMP_RESTART);
 377        machine_restart(cmd);
 378}
 379EXPORT_SYMBOL_GPL(kernel_restart);
 380
 381static void kernel_shutdown_prepare(enum system_states state)
 382{
 383        blocking_notifier_call_chain(&reboot_notifier_list,
 384                (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 385        system_state = state;
 386        usermodehelper_disable();
 387        device_shutdown();
 388}
 389/**
 390 *      kernel_halt - halt the system
 391 *
 392 *      Shutdown everything and perform a clean system halt.
 393 */
 394void kernel_halt(void)
 395{
 396        kernel_shutdown_prepare(SYSTEM_HALT);
 397        syscore_shutdown();
 398        printk(KERN_EMERG "System halted.\n");
 399        kmsg_dump(KMSG_DUMP_HALT);
 400        machine_halt();
 401}
 402
 403EXPORT_SYMBOL_GPL(kernel_halt);
 404
 405/**
 406 *      kernel_power_off - power_off the system
 407 *
 408 *      Shutdown everything and perform a clean system power_off.
 409 */
 410void kernel_power_off(void)
 411{
 412        kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 413        if (pm_power_off_prepare)
 414                pm_power_off_prepare();
 415        disable_nonboot_cpus();
 416        syscore_shutdown();
 417        printk(KERN_EMERG "Power down.\n");
 418        kmsg_dump(KMSG_DUMP_POWEROFF);
 419        machine_power_off();
 420}
 421EXPORT_SYMBOL_GPL(kernel_power_off);
 422
 423static DEFINE_MUTEX(reboot_mutex);
 424
 425/*
 426 * Reboot system call: for obvious reasons only root may call it,
 427 * and even root needs to set up some magic numbers in the registers
 428 * so that some mistake won't make this reboot the whole machine.
 429 * You can also set the meaning of the ctrl-alt-del-key here.
 430 *
 431 * reboot doesn't sync: do that yourself before calling this.
 432 */
 433SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 434                void __user *, arg)
 435{
 436        char buffer[256];
 437        int ret = 0;
 438
 439        /* We only trust the superuser with rebooting the system. */
 440        if (!capable(CAP_SYS_BOOT))
 441                return -EPERM;
 442
 443        /* For safety, we require "magic" arguments. */
 444        if (magic1 != LINUX_REBOOT_MAGIC1 ||
 445            (magic2 != LINUX_REBOOT_MAGIC2 &&
 446                        magic2 != LINUX_REBOOT_MAGIC2A &&
 447                        magic2 != LINUX_REBOOT_MAGIC2B &&
 448                        magic2 != LINUX_REBOOT_MAGIC2C))
 449                return -EINVAL;
 450
 451        /*
 452         * If pid namespaces are enabled and the current task is in a child
 453         * pid_namespace, the command is handled by reboot_pid_ns() which will
 454         * call do_exit().
 455         */
 456        ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
 457        if (ret)
 458                return ret;
 459
 460        /* Instead of trying to make the power_off code look like
 461         * halt when pm_power_off is not set do it the easy way.
 462         */
 463        if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 464                cmd = LINUX_REBOOT_CMD_HALT;
 465
 466        mutex_lock(&reboot_mutex);
 467        switch (cmd) {
 468        case LINUX_REBOOT_CMD_RESTART:
 469                kernel_restart(NULL);
 470                break;
 471
 472        case LINUX_REBOOT_CMD_CAD_ON:
 473                C_A_D = 1;
 474                break;
 475
 476        case LINUX_REBOOT_CMD_CAD_OFF:
 477                C_A_D = 0;
 478                break;
 479
 480        case LINUX_REBOOT_CMD_HALT:
 481                kernel_halt();
 482                do_exit(0);
 483                panic("cannot halt");
 484
 485        case LINUX_REBOOT_CMD_POWER_OFF:
 486                kernel_power_off();
 487                do_exit(0);
 488                break;
 489
 490        case LINUX_REBOOT_CMD_RESTART2:
 491                if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 492                        ret = -EFAULT;
 493                        break;
 494                }
 495                buffer[sizeof(buffer) - 1] = '\0';
 496
 497                kernel_restart(buffer);
 498                break;
 499
 500#ifdef CONFIG_KEXEC
 501        case LINUX_REBOOT_CMD_KEXEC:
 502                ret = kernel_kexec();
 503                break;
 504#endif
 505
 506#ifdef CONFIG_HIBERNATION
 507        case LINUX_REBOOT_CMD_SW_SUSPEND:
 508                ret = hibernate();
 509                break;
 510#endif
 511
 512        default:
 513                ret = -EINVAL;
 514                break;
 515        }
 516        mutex_unlock(&reboot_mutex);
 517        return ret;
 518}
 519
 520static void deferred_cad(struct work_struct *dummy)
 521{
 522        kernel_restart(NULL);
 523}
 524
 525/*
 526 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 527 * As it's called within an interrupt, it may NOT sync: the only choice
 528 * is whether to reboot at once, or just ignore the ctrl-alt-del.
 529 */
 530void ctrl_alt_del(void)
 531{
 532        static DECLARE_WORK(cad_work, deferred_cad);
 533
 534        if (C_A_D)
 535                schedule_work(&cad_work);
 536        else
 537                kill_cad_pid(SIGINT, 1);
 538}
 539        
 540/*
 541 * Unprivileged users may change the real gid to the effective gid
 542 * or vice versa.  (BSD-style)
 543 *
 544 * If you set the real gid at all, or set the effective gid to a value not
 545 * equal to the real gid, then the saved gid is set to the new effective gid.
 546 *
 547 * This makes it possible for a setgid program to completely drop its
 548 * privileges, which is often a useful assertion to make when you are doing
 549 * a security audit over a program.
 550 *
 551 * The general idea is that a program which uses just setregid() will be
 552 * 100% compatible with BSD.  A program which uses just setgid() will be
 553 * 100% compatible with POSIX with saved IDs. 
 554 *
 555 * SMP: There are not races, the GIDs are checked only by filesystem
 556 *      operations (as far as semantic preservation is concerned).
 557 */
 558SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 559{
 560        struct user_namespace *ns = current_user_ns();
 561        const struct cred *old;
 562        struct cred *new;
 563        int retval;
 564        kgid_t krgid, kegid;
 565
 566        krgid = make_kgid(ns, rgid);
 567        kegid = make_kgid(ns, egid);
 568
 569        if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 570                return -EINVAL;
 571        if ((egid != (gid_t) -1) && !gid_valid(kegid))
 572                return -EINVAL;
 573
 574        new = prepare_creds();
 575        if (!new)
 576                return -ENOMEM;
 577        old = current_cred();
 578
 579        retval = -EPERM;
 580        if (rgid != (gid_t) -1) {
 581                if (gid_eq(old->gid, krgid) ||
 582                    gid_eq(old->egid, krgid) ||
 583                    nsown_capable(CAP_SETGID))
 584                        new->gid = krgid;
 585                else
 586                        goto error;
 587        }
 588        if (egid != (gid_t) -1) {
 589                if (gid_eq(old->gid, kegid) ||
 590                    gid_eq(old->egid, kegid) ||
 591                    gid_eq(old->sgid, kegid) ||
 592                    nsown_capable(CAP_SETGID))
 593                        new->egid = kegid;
 594                else
 595                        goto error;
 596        }
 597
 598        if (rgid != (gid_t) -1 ||
 599            (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 600                new->sgid = new->egid;
 601        new->fsgid = new->egid;
 602
 603        return commit_creds(new);
 604
 605error:
 606        abort_creds(new);
 607        return retval;
 608}
 609
 610/*
 611 * setgid() is implemented like SysV w/ SAVED_IDS 
 612 *
 613 * SMP: Same implicit races as above.
 614 */
 615SYSCALL_DEFINE1(setgid, gid_t, gid)
 616{
 617        struct user_namespace *ns = current_user_ns();
 618        const struct cred *old;
 619        struct cred *new;
 620        int retval;
 621        kgid_t kgid;
 622
 623        kgid = make_kgid(ns, gid);
 624        if (!gid_valid(kgid))
 625                return -EINVAL;
 626
 627        new = prepare_creds();
 628        if (!new)
 629                return -ENOMEM;
 630        old = current_cred();
 631
 632        retval = -EPERM;
 633        if (nsown_capable(CAP_SETGID))
 634                new->gid = new->egid = new->sgid = new->fsgid = kgid;
 635        else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 636                new->egid = new->fsgid = kgid;
 637        else
 638                goto error;
 639
 640        return commit_creds(new);
 641
 642error:
 643        abort_creds(new);
 644        return retval;
 645}
 646
 647/*
 648 * change the user struct in a credentials set to match the new UID
 649 */
 650static int set_user(struct cred *new)
 651{
 652        struct user_struct *new_user;
 653
 654        new_user = alloc_uid(new->uid);
 655        if (!new_user)
 656                return -EAGAIN;
 657
 658        /*
 659         * We don't fail in case of NPROC limit excess here because too many
 660         * poorly written programs don't check set*uid() return code, assuming
 661         * it never fails if called by root.  We may still enforce NPROC limit
 662         * for programs doing set*uid()+execve() by harmlessly deferring the
 663         * failure to the execve() stage.
 664         */
 665        if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 666                        new_user != INIT_USER)
 667                current->flags |= PF_NPROC_EXCEEDED;
 668        else
 669                current->flags &= ~PF_NPROC_EXCEEDED;
 670
 671        free_uid(new->user);
 672        new->user = new_user;
 673        return 0;
 674}
 675
 676/*
 677 * Unprivileged users may change the real uid to the effective uid
 678 * or vice versa.  (BSD-style)
 679 *
 680 * If you set the real uid at all, or set the effective uid to a value not
 681 * equal to the real uid, then the saved uid is set to the new effective uid.
 682 *
 683 * This makes it possible for a setuid program to completely drop its
 684 * privileges, which is often a useful assertion to make when you are doing
 685 * a security audit over a program.
 686 *
 687 * The general idea is that a program which uses just setreuid() will be
 688 * 100% compatible with BSD.  A program which uses just setuid() will be
 689 * 100% compatible with POSIX with saved IDs. 
 690 */
 691SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 692{
 693        struct user_namespace *ns = current_user_ns();
 694        const struct cred *old;
 695        struct cred *new;
 696        int retval;
 697        kuid_t kruid, keuid;
 698
 699        kruid = make_kuid(ns, ruid);
 700        keuid = make_kuid(ns, euid);
 701
 702        if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 703                return -EINVAL;
 704        if ((euid != (uid_t) -1) && !uid_valid(keuid))
 705                return -EINVAL;
 706
 707        new = prepare_creds();
 708        if (!new)
 709                return -ENOMEM;
 710        old = current_cred();
 711
 712        retval = -EPERM;
 713        if (ruid != (uid_t) -1) {
 714                new->uid = kruid;
 715                if (!uid_eq(old->uid, kruid) &&
 716                    !uid_eq(old->euid, kruid) &&
 717                    !nsown_capable(CAP_SETUID))
 718                        goto error;
 719        }
 720
 721        if (euid != (uid_t) -1) {
 722                new->euid = keuid;
 723                if (!uid_eq(old->uid, keuid) &&
 724                    !uid_eq(old->euid, keuid) &&
 725                    !uid_eq(old->suid, keuid) &&
 726                    !nsown_capable(CAP_SETUID))
 727                        goto error;
 728        }
 729
 730        if (!uid_eq(new->uid, old->uid)) {
 731                retval = set_user(new);
 732                if (retval < 0)
 733                        goto error;
 734        }
 735        if (ruid != (uid_t) -1 ||
 736            (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 737                new->suid = new->euid;
 738        new->fsuid = new->euid;
 739
 740        retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 741        if (retval < 0)
 742                goto error;
 743
 744        return commit_creds(new);
 745
 746error:
 747        abort_creds(new);
 748        return retval;
 749}
 750                
 751/*
 752 * setuid() is implemented like SysV with SAVED_IDS 
 753 * 
 754 * Note that SAVED_ID's is deficient in that a setuid root program
 755 * like sendmail, for example, cannot set its uid to be a normal 
 756 * user and then switch back, because if you're root, setuid() sets
 757 * the saved uid too.  If you don't like this, blame the bright people
 758 * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 759 * will allow a root program to temporarily drop privileges and be able to
 760 * regain them by swapping the real and effective uid.  
 761 */
 762SYSCALL_DEFINE1(setuid, uid_t, uid)
 763{
 764        struct user_namespace *ns = current_user_ns();
 765        const struct cred *old;
 766        struct cred *new;
 767        int retval;
 768        kuid_t kuid;
 769
 770        kuid = make_kuid(ns, uid);
 771        if (!uid_valid(kuid))
 772                return -EINVAL;
 773
 774        new = prepare_creds();
 775        if (!new)
 776                return -ENOMEM;
 777        old = current_cred();
 778
 779        retval = -EPERM;
 780        if (nsown_capable(CAP_SETUID)) {
 781                new->suid = new->uid = kuid;
 782                if (!uid_eq(kuid, old->uid)) {
 783                        retval = set_user(new);
 784                        if (retval < 0)
 785                                goto error;
 786                }
 787        } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 788                goto error;
 789        }
 790
 791        new->fsuid = new->euid = kuid;
 792
 793        retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 794        if (retval < 0)
 795                goto error;
 796
 797        return commit_creds(new);
 798
 799error:
 800        abort_creds(new);
 801        return retval;
 802}
 803
 804
 805/*
 806 * This function implements a generic ability to update ruid, euid,
 807 * and suid.  This allows you to implement the 4.4 compatible seteuid().
 808 */
 809SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 810{
 811        struct user_namespace *ns = current_user_ns();
 812        const struct cred *old;
 813        struct cred *new;
 814        int retval;
 815        kuid_t kruid, keuid, ksuid;
 816
 817        kruid = make_kuid(ns, ruid);
 818        keuid = make_kuid(ns, euid);
 819        ksuid = make_kuid(ns, suid);
 820
 821        if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 822                return -EINVAL;
 823
 824        if ((euid != (uid_t) -1) && !uid_valid(keuid))
 825                return -EINVAL;
 826
 827        if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 828                return -EINVAL;
 829
 830        new = prepare_creds();
 831        if (!new)
 832                return -ENOMEM;
 833
 834        old = current_cred();
 835
 836        retval = -EPERM;
 837        if (!nsown_capable(CAP_SETUID)) {
 838                if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 839                    !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 840                        goto error;
 841                if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 842                    !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 843                        goto error;
 844                if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 845                    !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 846                        goto error;
 847        }
 848
 849        if (ruid != (uid_t) -1) {
 850                new->uid = kruid;
 851                if (!uid_eq(kruid, old->uid)) {
 852                        retval = set_user(new);
 853                        if (retval < 0)
 854                                goto error;
 855                }
 856        }
 857        if (euid != (uid_t) -1)
 858                new->euid = keuid;
 859        if (suid != (uid_t) -1)
 860                new->suid = ksuid;
 861        new->fsuid = new->euid;
 862
 863        retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 864        if (retval < 0)
 865                goto error;
 866
 867        return commit_creds(new);
 868
 869error:
 870        abort_creds(new);
 871        return retval;
 872}
 873
 874SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 875{
 876        const struct cred *cred = current_cred();
 877        int retval;
 878        uid_t ruid, euid, suid;
 879
 880        ruid = from_kuid_munged(cred->user_ns, cred->uid);
 881        euid = from_kuid_munged(cred->user_ns, cred->euid);
 882        suid = from_kuid_munged(cred->user_ns, cred->suid);
 883
 884        if (!(retval   = put_user(ruid, ruidp)) &&
 885            !(retval   = put_user(euid, euidp)))
 886                retval = put_user(suid, suidp);
 887
 888        return retval;
 889}
 890
 891/*
 892 * Same as above, but for rgid, egid, sgid.
 893 */
 894SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 895{
 896        struct user_namespace *ns = current_user_ns();
 897        const struct cred *old;
 898        struct cred *new;
 899        int retval;
 900        kgid_t krgid, kegid, ksgid;
 901
 902        krgid = make_kgid(ns, rgid);
 903        kegid = make_kgid(ns, egid);
 904        ksgid = make_kgid(ns, sgid);
 905
 906        if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 907                return -EINVAL;
 908        if ((egid != (gid_t) -1) && !gid_valid(kegid))
 909                return -EINVAL;
 910        if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 911                return -EINVAL;
 912
 913        new = prepare_creds();
 914        if (!new)
 915                return -ENOMEM;
 916        old = current_cred();
 917
 918        retval = -EPERM;
 919        if (!nsown_capable(CAP_SETGID)) {
 920                if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 921                    !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 922                        goto error;
 923                if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 924                    !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 925                        goto error;
 926                if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 927                    !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 928                        goto error;
 929        }
 930
 931        if (rgid != (gid_t) -1)
 932                new->gid = krgid;
 933        if (egid != (gid_t) -1)
 934                new->egid = kegid;
 935        if (sgid != (gid_t) -1)
 936                new->sgid = ksgid;
 937        new->fsgid = new->egid;
 938
 939        return commit_creds(new);
 940
 941error:
 942        abort_creds(new);
 943        return retval;
 944}
 945
 946SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 947{
 948        const struct cred *cred = current_cred();
 949        int retval;
 950        gid_t rgid, egid, sgid;
 951
 952        rgid = from_kgid_munged(cred->user_ns, cred->gid);
 953        egid = from_kgid_munged(cred->user_ns, cred->egid);
 954        sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 955
 956        if (!(retval   = put_user(rgid, rgidp)) &&
 957            !(retval   = put_user(egid, egidp)))
 958                retval = put_user(sgid, sgidp);
 959
 960        return retval;
 961}
 962
 963
 964/*
 965 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 966 * is used for "access()" and for the NFS daemon (letting nfsd stay at
 967 * whatever uid it wants to). It normally shadows "euid", except when
 968 * explicitly set by setfsuid() or for access..
 969 */
 970SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 971{
 972        const struct cred *old;
 973        struct cred *new;
 974        uid_t old_fsuid;
 975        kuid_t kuid;
 976
 977        old = current_cred();
 978        old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 979
 980        kuid = make_kuid(old->user_ns, uid);
 981        if (!uid_valid(kuid))
 982                return old_fsuid;
 983
 984        new = prepare_creds();
 985        if (!new)
 986                return old_fsuid;
 987
 988        if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 989            uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 990            nsown_capable(CAP_SETUID)) {
 991                if (!uid_eq(kuid, old->fsuid)) {
 992                        new->fsuid = kuid;
 993                        if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 994                                goto change_okay;
 995                }
 996        }
 997
 998        abort_creds(new);
 999        return old_fsuid;
1000
1001change_okay:
1002        commit_creds(new);
1003        return old_fsuid;
1004}
1005
1006/*
1007 * Samma på svenska..
1008 */
1009SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1010{
1011        const struct cred *old;
1012        struct cred *new;
1013        gid_t old_fsgid;
1014        kgid_t kgid;
1015
1016        old = current_cred();
1017        old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1018
1019        kgid = make_kgid(old->user_ns, gid);
1020        if (!gid_valid(kgid))
1021                return old_fsgid;
1022
1023        new = prepare_creds();
1024        if (!new)
1025                return old_fsgid;
1026
1027        if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
1028            gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1029            nsown_capable(CAP_SETGID)) {
1030                if (!gid_eq(kgid, old->fsgid)) {
1031                        new->fsgid = kgid;
1032                        goto change_okay;
1033                }
1034        }
1035
1036        abort_creds(new);
1037        return old_fsgid;
1038
1039change_okay:
1040        commit_creds(new);
1041        return old_fsgid;
1042}
1043
1044void do_sys_times(struct tms *tms)
1045{
1046        cputime_t tgutime, tgstime, cutime, cstime;
1047
1048        spin_lock_irq(&current->sighand->siglock);
1049        thread_group_times(current, &tgutime, &tgstime);
1050        cutime = current->signal->cutime;
1051        cstime = current->signal->cstime;
1052        spin_unlock_irq(&current->sighand->siglock);
1053        tms->tms_utime = cputime_to_clock_t(tgutime);
1054        tms->tms_stime = cputime_to_clock_t(tgstime);
1055        tms->tms_cutime = cputime_to_clock_t(cutime);
1056        tms->tms_cstime = cputime_to_clock_t(cstime);
1057}
1058
1059SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1060{
1061        if (tbuf) {
1062                struct tms tmp;
1063
1064                do_sys_times(&tmp);
1065                if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1066                        return -EFAULT;
1067        }
1068        force_successful_syscall_return();
1069        return (long) jiffies_64_to_clock_t(get_jiffies_64());
1070}
1071
1072/*
1073 * This needs some heavy checking ...
1074 * I just haven't the stomach for it. I also don't fully
1075 * understand sessions/pgrp etc. Let somebody who does explain it.
1076 *
1077 * OK, I think I have the protection semantics right.... this is really
1078 * only important on a multi-user system anyway, to make sure one user
1079 * can't send a signal to a process owned by another.  -TYT, 12/12/91
1080 *
1081 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1082 * LBT 04.03.94
1083 */
1084SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1085{
1086        struct task_struct *p;
1087        struct task_struct *group_leader = current->group_leader;
1088        struct pid *pgrp;
1089        int err;
1090
1091        if (!pid)
1092                pid = task_pid_vnr(group_leader);
1093        if (!pgid)
1094                pgid = pid;
1095        if (pgid < 0)
1096                return -EINVAL;
1097        rcu_read_lock();
1098
1099        /* From this point forward we keep holding onto the tasklist lock
1100         * so that our parent does not change from under us. -DaveM
1101         */
1102        write_lock_irq(&tasklist_lock);
1103
1104        err = -ESRCH;
1105        p = find_task_by_vpid(pid);
1106        if (!p)
1107                goto out;
1108
1109        err = -EINVAL;
1110        if (!thread_group_leader(p))
1111                goto out;
1112
1113        if (same_thread_group(p->real_parent, group_leader)) {
1114                err = -EPERM;
1115                if (task_session(p) != task_session(group_leader))
1116                        goto out;
1117                err = -EACCES;
1118                if (p->did_exec)
1119                        goto out;
1120        } else {
1121                err = -ESRCH;
1122                if (p != group_leader)
1123                        goto out;
1124        }
1125
1126        err = -EPERM;
1127        if (p->signal->leader)
1128                goto out;
1129
1130        pgrp = task_pid(p);
1131        if (pgid != pid) {
1132                struct task_struct *g;
1133
1134                pgrp = find_vpid(pgid);
1135                g = pid_task(pgrp, PIDTYPE_PGID);
1136                if (!g || task_session(g) != task_session(group_leader))
1137                        goto out;
1138        }
1139
1140        err = security_task_setpgid(p, pgid);
1141        if (err)
1142                goto out;
1143
1144        if (task_pgrp(p) != pgrp)
1145                change_pid(p, PIDTYPE_PGID, pgrp);
1146
1147        err = 0;
1148out:
1149        /* All paths lead to here, thus we are safe. -DaveM */
1150        write_unlock_irq(&tasklist_lock);
1151        rcu_read_unlock();
1152        return err;
1153}
1154
1155SYSCALL_DEFINE1(getpgid, pid_t, pid)
1156{
1157        struct task_struct *p;
1158        struct pid *grp;
1159        int retval;
1160
1161        rcu_read_lock();
1162        if (!pid)
1163                grp = task_pgrp(current);
1164        else {
1165                retval = -ESRCH;
1166                p = find_task_by_vpid(pid);
1167                if (!p)
1168                        goto out;
1169                grp = task_pgrp(p);
1170                if (!grp)
1171                        goto out;
1172
1173                retval = security_task_getpgid(p);
1174                if (retval)
1175                        goto out;
1176        }
1177        retval = pid_vnr(grp);
1178out:
1179        rcu_read_unlock();
1180        return retval;
1181}
1182
1183#ifdef __ARCH_WANT_SYS_GETPGRP
1184
1185SYSCALL_DEFINE0(getpgrp)
1186{
1187        return sys_getpgid(0);
1188}
1189
1190#endif
1191
1192SYSCALL_DEFINE1(getsid, pid_t, pid)
1193{
1194        struct task_struct *p;
1195        struct pid *sid;
1196        int retval;
1197
1198        rcu_read_lock();
1199        if (!pid)
1200                sid = task_session(current);
1201        else {
1202                retval = -ESRCH;
1203                p = find_task_by_vpid(pid);
1204                if (!p)
1205                        goto out;
1206                sid = task_session(p);
1207                if (!sid)
1208                        goto out;
1209
1210                retval = security_task_getsid(p);
1211                if (retval)
1212                        goto out;
1213        }
1214        retval = pid_vnr(sid);
1215out:
1216        rcu_read_unlock();
1217        return retval;
1218}
1219
1220SYSCALL_DEFINE0(setsid)
1221{
1222        struct task_struct *group_leader = current->group_leader;
1223        struct pid *sid = task_pid(group_leader);
1224        pid_t session = pid_vnr(sid);
1225        int err = -EPERM;
1226
1227        write_lock_irq(&tasklist_lock);
1228        /* Fail if I am already a session leader */
1229        if (group_leader->signal->leader)
1230                goto out;
1231
1232        /* Fail if a process group id already exists that equals the
1233         * proposed session id.
1234         */
1235        if (pid_task(sid, PIDTYPE_PGID))
1236                goto out;
1237
1238        group_leader->signal->leader = 1;
1239        __set_special_pids(sid);
1240
1241        proc_clear_tty(group_leader);
1242
1243        err = session;
1244out:
1245        write_unlock_irq(&tasklist_lock);
1246        if (err > 0) {
1247                proc_sid_connector(group_leader);
1248                sched_autogroup_create_attach(group_leader);
1249        }
1250        return err;
1251}
1252
1253DECLARE_RWSEM(uts_sem);
1254
1255#ifdef COMPAT_UTS_MACHINE
1256#define override_architecture(name) \
1257        (personality(current->personality) == PER_LINUX32 && \
1258         copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1259                      sizeof(COMPAT_UTS_MACHINE)))
1260#else
1261#define override_architecture(name)     0
1262#endif
1263
1264/*
1265 * Work around broken programs that cannot handle "Linux 3.0".
1266 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1267 */
1268static int override_release(char __user *release, size_t len)
1269{
1270        int ret = 0;
1271
1272        if (current->personality & UNAME26) {
1273                const char *rest = UTS_RELEASE;
1274                char buf[65] = { 0 };
1275                int ndots = 0;
1276                unsigned v;
1277                size_t copy;
1278
1279                while (*rest) {
1280                        if (*rest == '.' && ++ndots >= 3)
1281                                break;
1282                        if (!isdigit(*rest) && *rest != '.')
1283                                break;
1284                        rest++;
1285                }
1286                v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1287                copy = clamp_t(size_t, len, 1, sizeof(buf));
1288                copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1289                ret = copy_to_user(release, buf, copy + 1);
1290        }
1291        return ret;
1292}
1293
1294SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1295{
1296        int errno = 0;
1297
1298        down_read(&uts_sem);
1299        if (copy_to_user(name, utsname(), sizeof *name))
1300                errno = -EFAULT;
1301        up_read(&uts_sem);
1302
1303        if (!errno && override_release(name->release, sizeof(name->release)))
1304                errno = -EFAULT;
1305        if (!errno && override_architecture(name))
1306                errno = -EFAULT;
1307        return errno;
1308}
1309
1310#ifdef __ARCH_WANT_SYS_OLD_UNAME
1311/*
1312 * Old cruft
1313 */
1314SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1315{
1316        int error = 0;
1317
1318        if (!name)
1319                return -EFAULT;
1320
1321        down_read(&uts_sem);
1322        if (copy_to_user(name, utsname(), sizeof(*name)))
1323                error = -EFAULT;
1324        up_read(&uts_sem);
1325
1326        if (!error && override_release(name->release, sizeof(name->release)))
1327                error = -EFAULT;
1328        if (!error && override_architecture(name))
1329                error = -EFAULT;
1330        return error;
1331}
1332
1333SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1334{
1335        int error;
1336
1337        if (!name)
1338                return -EFAULT;
1339        if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1340                return -EFAULT;
1341
1342        down_read(&uts_sem);
1343        error = __copy_to_user(&name->sysname, &utsname()->sysname,
1344                               __OLD_UTS_LEN);
1345        error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1346        error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1347                                __OLD_UTS_LEN);
1348        error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1349        error |= __copy_to_user(&name->release, &utsname()->release,
1350                                __OLD_UTS_LEN);
1351        error |= __put_user(0, name->release + __OLD_UTS_LEN);
1352        error |= __copy_to_user(&name->version, &utsname()->version,
1353                                __OLD_UTS_LEN);
1354        error |= __put_user(0, name->version + __OLD_UTS_LEN);
1355        error |= __copy_to_user(&name->machine, &utsname()->machine,
1356                                __OLD_UTS_LEN);
1357        error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1358        up_read(&uts_sem);
1359
1360        if (!error && override_architecture(name))
1361                error = -EFAULT;
1362        if (!error && override_release(name->release, sizeof(name->release)))
1363                error = -EFAULT;
1364        return error ? -EFAULT : 0;
1365}
1366#endif
1367
1368SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1369{
1370        int errno;
1371        char tmp[__NEW_UTS_LEN];
1372
1373        if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1374                return -EPERM;
1375
1376        if (len < 0 || len > __NEW_UTS_LEN)
1377                return -EINVAL;
1378        down_write(&uts_sem);
1379        errno = -EFAULT;
1380        if (!copy_from_user(tmp, name, len)) {
1381                struct new_utsname *u = utsname();
1382
1383                memcpy(u->nodename, tmp, len);
1384                memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1385                errno = 0;
1386                uts_proc_notify(UTS_PROC_HOSTNAME);
1387        }
1388        up_write(&uts_sem);
1389        return errno;
1390}
1391
1392#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1393
1394SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1395{
1396        int i, errno;
1397        struct new_utsname *u;
1398
1399        if (len < 0)
1400                return -EINVAL;
1401        down_read(&uts_sem);
1402        u = utsname();
1403        i = 1 + strlen(u->nodename);
1404        if (i > len)
1405                i = len;
1406        errno = 0;
1407        if (copy_to_user(name, u->nodename, i))
1408                errno = -EFAULT;
1409        up_read(&uts_sem);
1410        return errno;
1411}
1412
1413#endif
1414
1415/*
1416 * Only setdomainname; getdomainname can be implemented by calling
1417 * uname()
1418 */
1419SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1420{
1421        int errno;
1422        char tmp[__NEW_UTS_LEN];
1423
1424        if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1425                return -EPERM;
1426        if (len < 0 || len > __NEW_UTS_LEN)
1427                return -EINVAL;
1428
1429        down_write(&uts_sem);
1430        errno = -EFAULT;
1431        if (!copy_from_user(tmp, name, len)) {
1432                struct new_utsname *u = utsname();
1433
1434                memcpy(u->domainname, tmp, len);
1435                memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1436                errno = 0;
1437                uts_proc_notify(UTS_PROC_DOMAINNAME);
1438        }
1439        up_write(&uts_sem);
1440        return errno;
1441}
1442
1443SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1444{
1445        struct rlimit value;
1446        int ret;
1447
1448        ret = do_prlimit(current, resource, NULL, &value);
1449        if (!ret)
1450                ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1451
1452        return ret;
1453}
1454
1455#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1456
1457/*
1458 *      Back compatibility for getrlimit. Needed for some apps.
1459 */
1460 
1461SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1462                struct rlimit __user *, rlim)
1463{
1464        struct rlimit x;
1465        if (resource >= RLIM_NLIMITS)
1466                return -EINVAL;
1467
1468        task_lock(current->group_leader);
1469        x = current->signal->rlim[resource];
1470        task_unlock(current->group_leader);
1471        if (x.rlim_cur > 0x7FFFFFFF)
1472                x.rlim_cur = 0x7FFFFFFF;
1473        if (x.rlim_max > 0x7FFFFFFF)
1474                x.rlim_max = 0x7FFFFFFF;
1475        return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1476}
1477
1478#endif
1479
1480static inline bool rlim64_is_infinity(__u64 rlim64)
1481{
1482#if BITS_PER_LONG < 64
1483        return rlim64 >= ULONG_MAX;
1484#else
1485        return rlim64 == RLIM64_INFINITY;
1486#endif
1487}
1488
1489static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1490{
1491        if (rlim->rlim_cur == RLIM_INFINITY)
1492                rlim64->rlim_cur = RLIM64_INFINITY;
1493        else
1494                rlim64->rlim_cur = rlim->rlim_cur;
1495        if (rlim->rlim_max == RLIM_INFINITY)
1496                rlim64->rlim_max = RLIM64_INFINITY;
1497        else
1498                rlim64->rlim_max = rlim->rlim_max;
1499}
1500
1501static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1502{
1503        if (rlim64_is_infinity(rlim64->rlim_cur))
1504                rlim->rlim_cur = RLIM_INFINITY;
1505        else
1506                rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1507        if (rlim64_is_infinity(rlim64->rlim_max))
1508                rlim->rlim_max = RLIM_INFINITY;
1509        else
1510                rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1511}
1512
1513/* make sure you are allowed to change @tsk limits before calling this */
1514int do_prlimit(struct task_struct *tsk, unsigned int resource,
1515                struct rlimit *new_rlim, struct rlimit *old_rlim)
1516{
1517        struct rlimit *rlim;
1518        int retval = 0;
1519
1520        if (resource >= RLIM_NLIMITS)
1521                return -EINVAL;
1522        if (new_rlim) {
1523                if (new_rlim->rlim_cur > new_rlim->rlim_max)
1524                        return -EINVAL;
1525                if (resource == RLIMIT_NOFILE &&
1526                                new_rlim->rlim_max > sysctl_nr_open)
1527                        return -EPERM;
1528        }
1529
1530        /* protect tsk->signal and tsk->sighand from disappearing */
1531        read_lock(&tasklist_lock);
1532        if (!tsk->sighand) {
1533                retval = -ESRCH;
1534                goto out;
1535        }
1536
1537        rlim = tsk->signal->rlim + resource;
1538        task_lock(tsk->group_leader);
1539        if (new_rlim) {
1540                /* Keep the capable check against init_user_ns until
1541                   cgroups can contain all limits */
1542                if (new_rlim->rlim_max > rlim->rlim_max &&
1543                                !capable(CAP_SYS_RESOURCE))
1544                        retval = -EPERM;
1545                if (!retval)
1546                        retval = security_task_setrlimit(tsk->group_leader,
1547                                        resource, new_rlim);
1548                if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1549                        /*
1550                         * The caller is asking for an immediate RLIMIT_CPU
1551                         * expiry.  But we use the zero value to mean "it was
1552                         * never set".  So let's cheat and make it one second
1553                         * instead
1554                         */
1555                        new_rlim->rlim_cur = 1;
1556                }
1557        }
1558        if (!retval) {
1559                if (old_rlim)
1560                        *old_rlim = *rlim;
1561                if (new_rlim)
1562                        *rlim = *new_rlim;
1563        }
1564        task_unlock(tsk->group_leader);
1565
1566        /*
1567         * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1568         * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1569         * very long-standing error, and fixing it now risks breakage of
1570         * applications, so we live with it
1571         */
1572         if (!retval && new_rlim && resource == RLIMIT_CPU &&
1573                         new_rlim->rlim_cur != RLIM_INFINITY)
1574                update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1575out:
1576        read_unlock(&tasklist_lock);
1577        return retval;
1578}
1579
1580/* rcu lock must be held */
1581static int check_prlimit_permission(struct task_struct *task)
1582{
1583        const struct cred *cred = current_cred(), *tcred;
1584
1585        if (current == task)
1586                return 0;
1587
1588        tcred = __task_cred(task);
1589        if (uid_eq(cred->uid, tcred->euid) &&
1590            uid_eq(cred->uid, tcred->suid) &&
1591            uid_eq(cred->uid, tcred->uid)  &&
1592            gid_eq(cred->gid, tcred->egid) &&
1593            gid_eq(cred->gid, tcred->sgid) &&
1594            gid_eq(cred->gid, tcred->gid))
1595                return 0;
1596        if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1597                return 0;
1598
1599        return -EPERM;
1600}
1601
1602SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1603                const struct rlimit64 __user *, new_rlim,
1604                struct rlimit64 __user *, old_rlim)
1605{
1606        struct rlimit64 old64, new64;
1607        struct rlimit old, new;
1608        struct task_struct *tsk;
1609        int ret;
1610
1611        if (new_rlim) {
1612                if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1613                        return -EFAULT;
1614                rlim64_to_rlim(&new64, &new);
1615        }
1616
1617        rcu_read_lock();
1618        tsk = pid ? find_task_by_vpid(pid) : current;
1619        if (!tsk) {
1620                rcu_read_unlock();
1621                return -ESRCH;
1622        }
1623        ret = check_prlimit_permission(tsk);
1624        if (ret) {
1625                rcu_read_unlock();
1626                return ret;
1627        }
1628        get_task_struct(tsk);
1629        rcu_read_unlock();
1630
1631        ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1632                        old_rlim ? &old : NULL);
1633
1634        if (!ret && old_rlim) {
1635                rlim_to_rlim64(&old, &old64);
1636                if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1637                        ret = -EFAULT;
1638        }
1639
1640        put_task_struct(tsk);
1641        return ret;
1642}
1643
1644SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1645{
1646        struct rlimit new_rlim;
1647
1648        if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1649                return -EFAULT;
1650        return do_prlimit(current, resource, &new_rlim, NULL);
1651}
1652
1653/*
1654 * It would make sense to put struct rusage in the task_struct,
1655 * except that would make the task_struct be *really big*.  After
1656 * task_struct gets moved into malloc'ed memory, it would
1657 * make sense to do this.  It will make moving the rest of the information
1658 * a lot simpler!  (Which we're not doing right now because we're not
1659 * measuring them yet).
1660 *
1661 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1662 * races with threads incrementing their own counters.  But since word
1663 * reads are atomic, we either get new values or old values and we don't
1664 * care which for the sums.  We always take the siglock to protect reading
1665 * the c* fields from p->signal from races with exit.c updating those
1666 * fields when reaping, so a sample either gets all the additions of a
1667 * given child after it's reaped, or none so this sample is before reaping.
1668 *
1669 * Locking:
1670 * We need to take the siglock for CHILDEREN, SELF and BOTH
1671 * for  the cases current multithreaded, non-current single threaded
1672 * non-current multithreaded.  Thread traversal is now safe with
1673 * the siglock held.
1674 * Strictly speaking, we donot need to take the siglock if we are current and
1675 * single threaded,  as no one else can take our signal_struct away, no one
1676 * else can  reap the  children to update signal->c* counters, and no one else
1677 * can race with the signal-> fields. If we do not take any lock, the
1678 * signal-> fields could be read out of order while another thread was just
1679 * exiting. So we should  place a read memory barrier when we avoid the lock.
1680 * On the writer side,  write memory barrier is implied in  __exit_signal
1681 * as __exit_signal releases  the siglock spinlock after updating the signal->
1682 * fields. But we don't do this yet to keep things simple.
1683 *
1684 */
1685
1686static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1687{
1688        r->ru_nvcsw += t->nvcsw;
1689        r->ru_nivcsw += t->nivcsw;
1690        r->ru_minflt += t->min_flt;
1691        r->ru_majflt += t->maj_flt;
1692        r->ru_inblock += task_io_get_inblock(t);
1693        r->ru_oublock += task_io_get_oublock(t);
1694}
1695
1696static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1697{
1698        struct task_struct *t;
1699        unsigned long flags;
1700        cputime_t tgutime, tgstime, utime, stime;
1701        unsigned long maxrss = 0;
1702
1703        memset((char *) r, 0, sizeof *r);
1704        utime = stime = 0;
1705
1706        if (who == RUSAGE_THREAD) {
1707                task_times(current, &utime, &stime);
1708                accumulate_thread_rusage(p, r);
1709                maxrss = p->signal->maxrss;
1710                goto out;
1711        }
1712
1713        if (!lock_task_sighand(p, &flags))
1714                return;
1715
1716        switch (who) {
1717                case RUSAGE_BOTH:
1718                case RUSAGE_CHILDREN:
1719                        utime = p->signal->cutime;
1720                        stime = p->signal->cstime;
1721                        r->ru_nvcsw = p->signal->cnvcsw;
1722                        r->ru_nivcsw = p->signal->cnivcsw;
1723                        r->ru_minflt = p->signal->cmin_flt;
1724                        r->ru_majflt = p->signal->cmaj_flt;
1725                        r->ru_inblock = p->signal->cinblock;
1726                        r->ru_oublock = p->signal->coublock;
1727                        maxrss = p->signal->cmaxrss;
1728
1729                        if (who == RUSAGE_CHILDREN)
1730                                break;
1731
1732                case RUSAGE_SELF:
1733                        thread_group_times(p, &tgutime, &tgstime);
1734                        utime += tgutime;
1735                        stime += tgstime;
1736                        r->ru_nvcsw += p->signal->nvcsw;
1737                        r->ru_nivcsw += p->signal->nivcsw;
1738                        r->ru_minflt += p->signal->min_flt;
1739                        r->ru_majflt += p->signal->maj_flt;
1740                        r->ru_inblock += p->signal->inblock;
1741                        r->ru_oublock += p->signal->oublock;
1742                        if (maxrss < p->signal->maxrss)
1743                                maxrss = p->signal->maxrss;
1744                        t = p;
1745                        do {
1746                                accumulate_thread_rusage(t, r);
1747                                t = next_thread(t);
1748                        } while (t != p);
1749                        break;
1750
1751                default:
1752                        BUG();
1753        }
1754        unlock_task_sighand(p, &flags);
1755
1756out:
1757        cputime_to_timeval(utime, &r->ru_utime);
1758        cputime_to_timeval(stime, &r->ru_stime);
1759
1760        if (who != RUSAGE_CHILDREN) {
1761                struct mm_struct *mm = get_task_mm(p);
1762                if (mm) {
1763                        setmax_mm_hiwater_rss(&maxrss, mm);
1764                        mmput(mm);
1765                }
1766        }
1767        r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1768}
1769
1770int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1771{
1772        struct rusage r;
1773        k_getrusage(p, who, &r);
1774        return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1775}
1776
1777SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1778{
1779        if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1780            who != RUSAGE_THREAD)
1781                return -EINVAL;
1782        return getrusage(current, who, ru);
1783}
1784
1785SYSCALL_DEFINE1(umask, int, mask)
1786{
1787        mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1788        return mask;
1789}
1790
1791#ifdef CONFIG_CHECKPOINT_RESTORE
1792static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1793{
1794        struct file *exe_file;
1795        struct dentry *dentry;
1796        int err;
1797
1798        exe_file = fget(fd);
1799        if (!exe_file)
1800                return -EBADF;
1801
1802        dentry = exe_file->f_path.dentry;
1803
1804        /*
1805         * Because the original mm->exe_file points to executable file, make
1806         * sure that this one is executable as well, to avoid breaking an
1807         * overall picture.
1808         */
1809        err = -EACCES;
1810        if (!S_ISREG(dentry->d_inode->i_mode)   ||
1811            exe_file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1812                goto exit;
1813
1814        err = inode_permission(dentry->d_inode, MAY_EXEC);
1815        if (err)
1816                goto exit;
1817
1818        down_write(&mm->mmap_sem);
1819
1820        /*
1821         * Forbid mm->exe_file change if old file still mapped.
1822         */
1823        err = -EBUSY;
1824        if (mm->exe_file) {
1825                struct vm_area_struct *vma;
1826
1827                for (vma = mm->mmap; vma; vma = vma->vm_next)
1828                        if (vma->vm_file &&
1829                            path_equal(&vma->vm_file->f_path,
1830                                       &mm->exe_file->f_path))
1831                                goto exit_unlock;
1832        }
1833
1834        /*
1835         * The symlink can be changed only once, just to disallow arbitrary
1836         * transitions malicious software might bring in. This means one
1837         * could make a snapshot over all processes running and monitor
1838         * /proc/pid/exe changes to notice unusual activity if needed.
1839         */
1840        err = -EPERM;
1841        if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1842                goto exit_unlock;
1843
1844        err = 0;
1845        set_mm_exe_file(mm, exe_file);
1846exit_unlock:
1847        up_write(&mm->mmap_sem);
1848
1849exit:
1850        fput(exe_file);
1851        return err;
1852}
1853
1854static int prctl_set_mm(int opt, unsigned long addr,
1855                        unsigned long arg4, unsigned long arg5)
1856{
1857        unsigned long rlim = rlimit(RLIMIT_DATA);
1858        struct mm_struct *mm = current->mm;
1859        struct vm_area_struct *vma;
1860        int error;
1861
1862        if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1863                return -EINVAL;
1864
1865        if (!capable(CAP_SYS_RESOURCE))
1866                return -EPERM;
1867
1868        if (opt == PR_SET_MM_EXE_FILE)
1869                return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1870
1871        if (addr >= TASK_SIZE || addr < mmap_min_addr)
1872                return -EINVAL;
1873
1874        error = -EINVAL;
1875
1876        down_read(&mm->mmap_sem);
1877        vma = find_vma(mm, addr);
1878
1879        switch (opt) {
1880        case PR_SET_MM_START_CODE:
1881                mm->start_code = addr;
1882                break;
1883        case PR_SET_MM_END_CODE:
1884                mm->end_code = addr;
1885                break;
1886        case PR_SET_MM_START_DATA:
1887                mm->start_data = addr;
1888                break;
1889        case PR_SET_MM_END_DATA:
1890                mm->end_data = addr;
1891                break;
1892
1893        case PR_SET_MM_START_BRK:
1894                if (addr <= mm->end_data)
1895                        goto out;
1896
1897                if (rlim < RLIM_INFINITY &&
1898                    (mm->brk - addr) +
1899                    (mm->end_data - mm->start_data) > rlim)
1900                        goto out;
1901
1902                mm->start_brk = addr;
1903                break;
1904
1905        case PR_SET_MM_BRK:
1906                if (addr <= mm->end_data)
1907                        goto out;
1908
1909                if (rlim < RLIM_INFINITY &&
1910                    (addr - mm->start_brk) +
1911                    (mm->end_data - mm->start_data) > rlim)
1912                        goto out;
1913
1914                mm->brk = addr;
1915                break;
1916
1917        /*
1918         * If command line arguments and environment
1919         * are placed somewhere else on stack, we can
1920         * set them up here, ARG_START/END to setup
1921         * command line argumets and ENV_START/END
1922         * for environment.
1923         */
1924        case PR_SET_MM_START_STACK:
1925        case PR_SET_MM_ARG_START:
1926        case PR_SET_MM_ARG_END:
1927        case PR_SET_MM_ENV_START:
1928        case PR_SET_MM_ENV_END:
1929                if (!vma) {
1930                        error = -EFAULT;
1931                        goto out;
1932                }
1933                if (opt == PR_SET_MM_START_STACK)
1934                        mm->start_stack = addr;
1935                else if (opt == PR_SET_MM_ARG_START)
1936                        mm->arg_start = addr;
1937                else if (opt == PR_SET_MM_ARG_END)
1938                        mm->arg_end = addr;
1939                else if (opt == PR_SET_MM_ENV_START)
1940                        mm->env_start = addr;
1941                else if (opt == PR_SET_MM_ENV_END)
1942                        mm->env_end = addr;
1943                break;
1944
1945        /*
1946         * This doesn't move auxiliary vector itself
1947         * since it's pinned to mm_struct, but allow
1948         * to fill vector with new values. It's up
1949         * to a caller to provide sane values here
1950         * otherwise user space tools which use this
1951         * vector might be unhappy.
1952         */
1953        case PR_SET_MM_AUXV: {
1954                unsigned long user_auxv[AT_VECTOR_SIZE];
1955
1956                if (arg4 > sizeof(user_auxv))
1957                        goto out;
1958                up_read(&mm->mmap_sem);
1959
1960                if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1961                        return -EFAULT;
1962
1963                /* Make sure the last entry is always AT_NULL */
1964                user_auxv[AT_VECTOR_SIZE - 2] = 0;
1965                user_auxv[AT_VECTOR_SIZE - 1] = 0;
1966
1967                BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1968
1969                task_lock(current);
1970                memcpy(mm->saved_auxv, user_auxv, arg4);
1971                task_unlock(current);
1972
1973                return 0;
1974        }
1975        default:
1976                goto out;
1977        }
1978
1979        error = 0;
1980out:
1981        up_read(&mm->mmap_sem);
1982        return error;
1983}
1984
1985static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1986{
1987        return put_user(me->clear_child_tid, tid_addr);
1988}
1989
1990#else /* CONFIG_CHECKPOINT_RESTORE */
1991static int prctl_set_mm(int opt, unsigned long addr,
1992                        unsigned long arg4, unsigned long arg5)
1993{
1994        return -EINVAL;
1995}
1996static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1997{
1998        return -EINVAL;
1999}
2000#endif
2001
2002SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2003                unsigned long, arg4, unsigned long, arg5)
2004{
2005        struct task_struct *me = current;
2006        unsigned char comm[sizeof(me->comm)];
2007        long error;
2008
2009        error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2010        if (error != -ENOSYS)
2011                return error;
2012
2013        error = 0;
2014        switch (option) {
2015                case PR_SET_PDEATHSIG:
2016                        if (!valid_signal(arg2)) {
2017                                error = -EINVAL;
2018                                break;
2019                        }
2020                        me->pdeath_signal = arg2;
2021                        break;
2022                case PR_GET_PDEATHSIG:
2023                        error = put_user(me->pdeath_signal, (int __user *)arg2);
2024                        break;
2025                case PR_GET_DUMPABLE:
2026                        error = get_dumpable(me->mm);
2027                        break;
2028                case PR_SET_DUMPABLE:
2029                        if (arg2 < 0 || arg2 > 1) {
2030                                error = -EINVAL;
2031                                break;
2032                        }
2033                        set_dumpable(me->mm, arg2);
2034                        break;
2035
2036                case PR_SET_UNALIGN:
2037                        error = SET_UNALIGN_CTL(me, arg2);
2038                        break;
2039                case PR_GET_UNALIGN:
2040                        error = GET_UNALIGN_CTL(me, arg2);
2041                        break;
2042                case PR_SET_FPEMU:
2043                        error = SET_FPEMU_CTL(me, arg2);
2044                        break;
2045                case PR_GET_FPEMU:
2046                        error = GET_FPEMU_CTL(me, arg2);
2047                        break;
2048                case PR_SET_FPEXC:
2049                        error = SET_FPEXC_CTL(me, arg2);
2050                        break;
2051                case PR_GET_FPEXC:
2052                        error = GET_FPEXC_CTL(me, arg2);
2053                        break;
2054                case PR_GET_TIMING:
2055                        error = PR_TIMING_STATISTICAL;
2056                        break;
2057                case PR_SET_TIMING:
2058                        if (arg2 != PR_TIMING_STATISTICAL)
2059                                error = -EINVAL;
2060                        break;
2061                case PR_SET_NAME:
2062                        comm[sizeof(me->comm)-1] = 0;
2063                        if (strncpy_from_user(comm, (char __user *)arg2,
2064                                              sizeof(me->comm) - 1) < 0)
2065                                return -EFAULT;
2066                        set_task_comm(me, comm);
2067                        proc_comm_connector(me);
2068                        break;
2069                case PR_GET_NAME:
2070                        get_task_comm(comm, me);
2071                        if (copy_to_user((char __user *)arg2, comm,
2072                                         sizeof(comm)))
2073                                return -EFAULT;
2074                        break;
2075                case PR_GET_ENDIAN:
2076                        error = GET_ENDIAN(me, arg2);
2077                        break;
2078                case PR_SET_ENDIAN:
2079                        error = SET_ENDIAN(me, arg2);
2080                        break;
2081                case PR_GET_SECCOMP:
2082                        error = prctl_get_seccomp();
2083                        break;
2084                case PR_SET_SECCOMP:
2085                        error = prctl_set_seccomp(arg2, (char __user *)arg3);
2086                        break;
2087                case PR_GET_TSC:
2088                        error = GET_TSC_CTL(arg2);
2089                        break;
2090                case PR_SET_TSC:
2091                        error = SET_TSC_CTL(arg2);
2092                        break;
2093                case PR_TASK_PERF_EVENTS_DISABLE:
2094                        error = perf_event_task_disable();
2095                        break;
2096                case PR_TASK_PERF_EVENTS_ENABLE:
2097                        error = perf_event_task_enable();
2098                        break;
2099                case PR_GET_TIMERSLACK:
2100                        error = current->timer_slack_ns;
2101                        break;
2102                case PR_SET_TIMERSLACK:
2103                        if (arg2 <= 0)
2104                                current->timer_slack_ns =
2105                                        current->default_timer_slack_ns;
2106                        else
2107                                current->timer_slack_ns = arg2;
2108                        break;
2109                case PR_MCE_KILL:
2110                        if (arg4 | arg5)
2111                                return -EINVAL;
2112                        switch (arg2) {
2113                        case PR_MCE_KILL_CLEAR:
2114                                if (arg3 != 0)
2115                                        return -EINVAL;
2116                                current->flags &= ~PF_MCE_PROCESS;
2117                                break;
2118                        case PR_MCE_KILL_SET:
2119                                current->flags |= PF_MCE_PROCESS;
2120                                if (arg3 == PR_MCE_KILL_EARLY)
2121                                        current->flags |= PF_MCE_EARLY;
2122                                else if (arg3 == PR_MCE_KILL_LATE)
2123                                        current->flags &= ~PF_MCE_EARLY;
2124                                else if (arg3 == PR_MCE_KILL_DEFAULT)
2125                                        current->flags &=
2126                                                ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2127                                else
2128                                        return -EINVAL;
2129                                break;
2130                        default:
2131                                return -EINVAL;
2132                        }
2133                        break;
2134                case PR_MCE_KILL_GET:
2135                        if (arg2 | arg3 | arg4 | arg5)
2136                                return -EINVAL;
2137                        if (current->flags & PF_MCE_PROCESS)
2138                                error = (current->flags & PF_MCE_EARLY) ?
2139                                        PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2140                        else
2141                                error = PR_MCE_KILL_DEFAULT;
2142                        break;
2143                case PR_SET_MM:
2144                        error = prctl_set_mm(arg2, arg3, arg4, arg5);
2145                        break;
2146                case PR_GET_TID_ADDRESS:
2147                        error = prctl_get_tid_address(me, (int __user **)arg2);
2148                        break;
2149                case PR_SET_CHILD_SUBREAPER:
2150                        me->signal->is_child_subreaper = !!arg2;
2151                        break;
2152                case PR_GET_CHILD_SUBREAPER:
2153                        error = put_user(me->signal->is_child_subreaper,
2154                                         (int __user *) arg2);
2155                        break;
2156                case PR_SET_NO_NEW_PRIVS:
2157                        if (arg2 != 1 || arg3 || arg4 || arg5)
2158                                return -EINVAL;
2159
2160                        current->no_new_privs = 1;
2161                        break;
2162                case PR_GET_NO_NEW_PRIVS:
2163                        if (arg2 || arg3 || arg4 || arg5)
2164                                return -EINVAL;
2165                        return current->no_new_privs ? 1 : 0;
2166                default:
2167                        error = -EINVAL;
2168                        break;
2169        }
2170        return error;
2171}
2172
2173SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2174                struct getcpu_cache __user *, unused)
2175{
2176        int err = 0;
2177        int cpu = raw_smp_processor_id();
2178        if (cpup)
2179                err |= put_user(cpu, cpup);
2180        if (nodep)
2181                err |= put_user(cpu_to_node(cpu), nodep);
2182        return err ? -EFAULT : 0;
2183}
2184
2185char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2186
2187static void argv_cleanup(struct subprocess_info *info)
2188{
2189        argv_free(info->argv);
2190}
2191
2192static int __orderly_poweroff(void)
2193{
2194        int argc;
2195        char **argv;
2196        static char *envp[] = {
2197                "HOME=/",
2198                "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2199                NULL
2200        };
2201        int ret;
2202
2203        argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2204        if (argv == NULL) {
2205                printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2206                       __func__, poweroff_cmd);
2207                return -ENOMEM;
2208        }
2209
2210        ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
2211                                      NULL, argv_cleanup, NULL);
2212        if (ret == -ENOMEM)
2213                argv_free(argv);
2214
2215        return ret;
2216}
2217
2218/**
2219 * orderly_poweroff - Trigger an orderly system poweroff
2220 * @force: force poweroff if command execution fails
2221 *
2222 * This may be called from any context to trigger a system shutdown.
2223 * If the orderly shutdown fails, it will force an immediate shutdown.
2224 */
2225int orderly_poweroff(bool force)
2226{
2227        int ret = __orderly_poweroff();
2228
2229        if (ret && force) {
2230                printk(KERN_WARNING "Failed to start orderly shutdown: "
2231                       "forcing the issue\n");
2232
2233                /*
2234                 * I guess this should try to kick off some daemon to sync and
2235                 * poweroff asap.  Or not even bother syncing if we're doing an
2236                 * emergency shutdown?
2237                 */
2238                emergency_sync();
2239                kernel_power_off();
2240        }
2241
2242        return ret;
2243}
2244EXPORT_SYMBOL_GPL(orderly_poweroff);
2245
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