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#include <linux/binfmts.h>
  51
  52#include <linux/kmsg_dump.h>
  53/* Move somewhere else to avoid recompiling? */
  54#include <generated/utsrelease.h>
  55
  56#include <asm/uaccess.h>
  57#include <asm/io.h>
  58#include <asm/unistd.h>
  59
  60#ifndef SET_UNALIGN_CTL
  61# define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  62#endif
  63#ifndef GET_UNALIGN_CTL
  64# define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  65#endif
  66#ifndef SET_FPEMU_CTL
  67# define SET_FPEMU_CTL(a,b)     (-EINVAL)
  68#endif
  69#ifndef GET_FPEMU_CTL
  70# define GET_FPEMU_CTL(a,b)     (-EINVAL)
  71#endif
  72#ifndef SET_FPEXC_CTL
  73# define SET_FPEXC_CTL(a,b)     (-EINVAL)
  74#endif
  75#ifndef GET_FPEXC_CTL
  76# define GET_FPEXC_CTL(a,b)     (-EINVAL)
  77#endif
  78#ifndef GET_ENDIAN
  79# define GET_ENDIAN(a,b)        (-EINVAL)
  80#endif
  81#ifndef SET_ENDIAN
  82# define SET_ENDIAN(a,b)        (-EINVAL)
  83#endif
  84#ifndef GET_TSC_CTL
  85# define GET_TSC_CTL(a)         (-EINVAL)
  86#endif
  87#ifndef SET_TSC_CTL
  88# define SET_TSC_CTL(a)         (-EINVAL)
  89#endif
  90
  91/*
  92 * this is where the system-wide overflow UID and GID are defined, for
  93 * architectures that now have 32-bit UID/GID but didn't in the past
  94 */
  95
  96int overflowuid = DEFAULT_OVERFLOWUID;
  97int overflowgid = DEFAULT_OVERFLOWGID;
  98
  99EXPORT_SYMBOL(overflowuid);
 100EXPORT_SYMBOL(overflowgid);
 101
 102/*
 103 * the same as above, but for filesystems which can only store a 16-bit
 104 * UID and GID. as such, this is needed on all architectures
 105 */
 106
 107int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 108int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 109
 110EXPORT_SYMBOL(fs_overflowuid);
 111EXPORT_SYMBOL(fs_overflowgid);
 112
 113/*
 114 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 115 */
 116
 117int C_A_D = 1;
 118struct pid *cad_pid;
 119EXPORT_SYMBOL(cad_pid);
 120
 121/*
 122 * If set, this is used for preparing the system to power off.
 123 */
 124
 125void (*pm_power_off_prepare)(void);
 126
 127/*
 128 * Returns true if current's euid is same as p's uid or euid,
 129 * or has CAP_SYS_NICE to p's user_ns.
 130 *
 131 * Called with rcu_read_lock, creds are safe
 132 */
 133static bool set_one_prio_perm(struct task_struct *p)
 134{
 135        const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 136
 137        if (uid_eq(pcred->uid,  cred->euid) ||
 138            uid_eq(pcred->euid, cred->euid))
 139                return true;
 140        if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
 141                return true;
 142        return false;
 143}
 144
 145/*
 146 * set the priority of a task
 147 * - the caller must hold the RCU read lock
 148 */
 149static int set_one_prio(struct task_struct *p, int niceval, int error)
 150{
 151        int no_nice;
 152
 153        if (!set_one_prio_perm(p)) {
 154                error = -EPERM;
 155                goto out;
 156        }
 157        if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 158                error = -EACCES;
 159                goto out;
 160        }
 161        no_nice = security_task_setnice(p, niceval);
 162        if (no_nice) {
 163                error = no_nice;
 164                goto out;
 165        }
 166        if (error == -ESRCH)
 167                error = 0;
 168        set_user_nice(p, niceval);
 169out:
 170        return error;
 171}
 172
 173SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 174{
 175        struct task_struct *g, *p;
 176        struct user_struct *user;
 177        const struct cred *cred = current_cred();
 178        int error = -EINVAL;
 179        struct pid *pgrp;
 180        kuid_t uid;
 181
 182        if (which > PRIO_USER || which < PRIO_PROCESS)
 183                goto out;
 184
 185        /* normalize: avoid signed division (rounding problems) */
 186        error = -ESRCH;
 187        if (niceval < -20)
 188                niceval = -20;
 189        if (niceval > 19)
 190                niceval = 19;
 191
 192        rcu_read_lock();
 193        read_lock(&tasklist_lock);
 194        switch (which) {
 195                case PRIO_PROCESS:
 196                        if (who)
 197                                p = find_task_by_vpid(who);
 198                        else
 199                                p = current;
 200                        if (p)
 201                                error = set_one_prio(p, niceval, error);
 202                        break;
 203                case PRIO_PGRP:
 204                        if (who)
 205                                pgrp = find_vpid(who);
 206                        else
 207                                pgrp = task_pgrp(current);
 208                        do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 209                                error = set_one_prio(p, niceval, error);
 210                        } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 211                        break;
 212                case PRIO_USER:
 213                        uid = make_kuid(cred->user_ns, who);
 214                        user = cred->user;
 215                        if (!who)
 216                                uid = cred->uid;
 217                        else if (!uid_eq(uid, cred->uid) &&
 218                                 !(user = find_user(uid)))
 219                                goto out_unlock;        /* No processes for this user */
 220
 221                        do_each_thread(g, p) {
 222                                if (uid_eq(task_uid(p), uid))
 223                                        error = set_one_prio(p, niceval, error);
 224                        } while_each_thread(g, p);
 225                        if (!uid_eq(uid, cred->uid))
 226                                free_uid(user);         /* For find_user() */
 227                        break;
 228        }
 229out_unlock:
 230        read_unlock(&tasklist_lock);
 231        rcu_read_unlock();
 232out:
 233        return error;
 234}
 235
 236/*
 237 * Ugh. To avoid negative return values, "getpriority()" will
 238 * not return the normal nice-value, but a negated value that
 239 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 240 * to stay compatible.
 241 */
 242SYSCALL_DEFINE2(getpriority, int, which, int, who)
 243{
 244        struct task_struct *g, *p;
 245        struct user_struct *user;
 246        const struct cred *cred = current_cred();
 247        long niceval, retval = -ESRCH;
 248        struct pid *pgrp;
 249        kuid_t uid;
 250
 251        if (which > PRIO_USER || which < PRIO_PROCESS)
 252                return -EINVAL;
 253
 254        rcu_read_lock();
 255        read_lock(&tasklist_lock);
 256        switch (which) {
 257                case PRIO_PROCESS:
 258                        if (who)
 259                                p = find_task_by_vpid(who);
 260                        else
 261                                p = current;
 262                        if (p) {
 263                                niceval = 20 - task_nice(p);
 264                                if (niceval > retval)
 265                                        retval = niceval;
 266                        }
 267                        break;
 268                case PRIO_PGRP:
 269                        if (who)
 270                                pgrp = find_vpid(who);
 271                        else
 272                                pgrp = task_pgrp(current);
 273                        do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 274                                niceval = 20 - task_nice(p);
 275                                if (niceval > retval)
 276                                        retval = niceval;
 277                        } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 278                        break;
 279                case PRIO_USER:
 280                        uid = make_kuid(cred->user_ns, who);
 281                        user = cred->user;
 282                        if (!who)
 283                                uid = cred->uid;
 284                        else if (!uid_eq(uid, cred->uid) &&
 285                                 !(user = find_user(uid)))
 286                                goto out_unlock;        /* No processes for this user */
 287
 288                        do_each_thread(g, p) {
 289                                if (uid_eq(task_uid(p), uid)) {
 290                                        niceval = 20 - task_nice(p);
 291                                        if (niceval > retval)
 292                                                retval = niceval;
 293                                }
 294                        } while_each_thread(g, p);
 295                        if (!uid_eq(uid, cred->uid))
 296                                free_uid(user);         /* for find_user() */
 297                        break;
 298        }
 299out_unlock:
 300        read_unlock(&tasklist_lock);
 301        rcu_read_unlock();
 302
 303        return retval;
 304}
 305
 306/**
 307 *      emergency_restart - reboot the system
 308 *
 309 *      Without shutting down any hardware or taking any locks
 310 *      reboot the system.  This is called when we know we are in
 311 *      trouble so this is our best effort to reboot.  This is
 312 *      safe to call in interrupt context.
 313 */
 314void emergency_restart(void)
 315{
 316        kmsg_dump(KMSG_DUMP_EMERG);
 317        machine_emergency_restart();
 318}
 319EXPORT_SYMBOL_GPL(emergency_restart);
 320
 321void kernel_restart_prepare(char *cmd)
 322{
 323        blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 324        system_state = SYSTEM_RESTART;
 325        usermodehelper_disable();
 326        device_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        syscore_shutdown();
 373        if (!cmd)
 374                printk(KERN_EMERG "Restarting system.\n");
 375        else
 376                printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 377        kmsg_dump(KMSG_DUMP_RESTART);
 378        machine_restart(cmd);
 379}
 380EXPORT_SYMBOL_GPL(kernel_restart);
 381
 382static void kernel_shutdown_prepare(enum system_states state)
 383{
 384        blocking_notifier_call_chain(&reboot_notifier_list,
 385                (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 386        system_state = state;
 387        usermodehelper_disable();
 388        device_shutdown();
 389}
 390/**
 391 *      kernel_halt - halt the system
 392 *
 393 *      Shutdown everything and perform a clean system halt.
 394 */
 395void kernel_halt(void)
 396{
 397        kernel_shutdown_prepare(SYSTEM_HALT);
 398        disable_nonboot_cpus();
 399        syscore_shutdown();
 400        printk(KERN_EMERG "System halted.\n");
 401        kmsg_dump(KMSG_DUMP_HALT);
 402        machine_halt();
 403}
 404
 405EXPORT_SYMBOL_GPL(kernel_halt);
 406
 407/**
 408 *      kernel_power_off - power_off the system
 409 *
 410 *      Shutdown everything and perform a clean system power_off.
 411 */
 412void kernel_power_off(void)
 413{
 414        kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 415        if (pm_power_off_prepare)
 416                pm_power_off_prepare();
 417        disable_nonboot_cpus();
 418        syscore_shutdown();
 419        printk(KERN_EMERG "Power down.\n");
 420        kmsg_dump(KMSG_DUMP_POWEROFF);
 421        machine_power_off();
 422}
 423EXPORT_SYMBOL_GPL(kernel_power_off);
 424
 425static DEFINE_MUTEX(reboot_mutex);
 426
 427/*
 428 * Reboot system call: for obvious reasons only root may call it,
 429 * and even root needs to set up some magic numbers in the registers
 430 * so that some mistake won't make this reboot the whole machine.
 431 * You can also set the meaning of the ctrl-alt-del-key here.
 432 *
 433 * reboot doesn't sync: do that yourself before calling this.
 434 */
 435SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 436                void __user *, arg)
 437{
 438        struct pid_namespace *pid_ns = task_active_pid_ns(current);
 439        char buffer[256];
 440        int ret = 0;
 441
 442        /* We only trust the superuser with rebooting the system. */
 443        if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
 444                return -EPERM;
 445
 446        /* For safety, we require "magic" arguments. */
 447        if (magic1 != LINUX_REBOOT_MAGIC1 ||
 448            (magic2 != LINUX_REBOOT_MAGIC2 &&
 449                        magic2 != LINUX_REBOOT_MAGIC2A &&
 450                        magic2 != LINUX_REBOOT_MAGIC2B &&
 451                        magic2 != LINUX_REBOOT_MAGIC2C))
 452                return -EINVAL;
 453
 454        /*
 455         * If pid namespaces are enabled and the current task is in a child
 456         * pid_namespace, the command is handled by reboot_pid_ns() which will
 457         * call do_exit().
 458         */
 459        ret = reboot_pid_ns(pid_ns, cmd);
 460        if (ret)
 461                return ret;
 462
 463        /* Instead of trying to make the power_off code look like
 464         * halt when pm_power_off is not set do it the easy way.
 465         */
 466        if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 467                cmd = LINUX_REBOOT_CMD_HALT;
 468
 469        mutex_lock(&reboot_mutex);
 470        switch (cmd) {
 471        case LINUX_REBOOT_CMD_RESTART:
 472                kernel_restart(NULL);
 473                break;
 474
 475        case LINUX_REBOOT_CMD_CAD_ON:
 476                C_A_D = 1;
 477                break;
 478
 479        case LINUX_REBOOT_CMD_CAD_OFF:
 480                C_A_D = 0;
 481                break;
 482
 483        case LINUX_REBOOT_CMD_HALT:
 484                kernel_halt();
 485                do_exit(0);
 486                panic("cannot halt");
 487
 488        case LINUX_REBOOT_CMD_POWER_OFF:
 489                kernel_power_off();
 490                do_exit(0);
 491                break;
 492
 493        case LINUX_REBOOT_CMD_RESTART2:
 494                if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 495                        ret = -EFAULT;
 496                        break;
 497                }
 498                buffer[sizeof(buffer) - 1] = '\0';
 499
 500                kernel_restart(buffer);
 501                break;
 502
 503#ifdef CONFIG_KEXEC
 504        case LINUX_REBOOT_CMD_KEXEC:
 505                ret = kernel_kexec();
 506                break;
 507#endif
 508
 509#ifdef CONFIG_HIBERNATION
 510        case LINUX_REBOOT_CMD_SW_SUSPEND:
 511                ret = hibernate();
 512                break;
 513#endif
 514
 515        default:
 516                ret = -EINVAL;
 517                break;
 518        }
 519        mutex_unlock(&reboot_mutex);
 520        return ret;
 521}
 522
 523static void deferred_cad(struct work_struct *dummy)
 524{
 525        kernel_restart(NULL);
 526}
 527
 528/*
 529 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 530 * As it's called within an interrupt, it may NOT sync: the only choice
 531 * is whether to reboot at once, or just ignore the ctrl-alt-del.
 532 */
 533void ctrl_alt_del(void)
 534{
 535        static DECLARE_WORK(cad_work, deferred_cad);
 536
 537        if (C_A_D)
 538                schedule_work(&cad_work);
 539        else
 540                kill_cad_pid(SIGINT, 1);
 541}
 542        
 543/*
 544 * Unprivileged users may change the real gid to the effective gid
 545 * or vice versa.  (BSD-style)
 546 *
 547 * If you set the real gid at all, or set the effective gid to a value not
 548 * equal to the real gid, then the saved gid is set to the new effective gid.
 549 *
 550 * This makes it possible for a setgid program to completely drop its
 551 * privileges, which is often a useful assertion to make when you are doing
 552 * a security audit over a program.
 553 *
 554 * The general idea is that a program which uses just setregid() will be
 555 * 100% compatible with BSD.  A program which uses just setgid() will be
 556 * 100% compatible with POSIX with saved IDs. 
 557 *
 558 * SMP: There are not races, the GIDs are checked only by filesystem
 559 *      operations (as far as semantic preservation is concerned).
 560 */
 561SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 562{
 563        struct user_namespace *ns = current_user_ns();
 564        const struct cred *old;
 565        struct cred *new;
 566        int retval;
 567        kgid_t krgid, kegid;
 568
 569        krgid = make_kgid(ns, rgid);
 570        kegid = make_kgid(ns, egid);
 571
 572        if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 573                return -EINVAL;
 574        if ((egid != (gid_t) -1) && !gid_valid(kegid))
 575                return -EINVAL;
 576
 577        new = prepare_creds();
 578        if (!new)
 579                return -ENOMEM;
 580        old = current_cred();
 581
 582        retval = -EPERM;
 583        if (rgid != (gid_t) -1) {
 584                if (gid_eq(old->gid, krgid) ||
 585                    gid_eq(old->egid, krgid) ||
 586                    nsown_capable(CAP_SETGID))
 587                        new->gid = krgid;
 588                else
 589                        goto error;
 590        }
 591        if (egid != (gid_t) -1) {
 592                if (gid_eq(old->gid, kegid) ||
 593                    gid_eq(old->egid, kegid) ||
 594                    gid_eq(old->sgid, kegid) ||
 595                    nsown_capable(CAP_SETGID))
 596                        new->egid = kegid;
 597                else
 598                        goto error;
 599        }
 600
 601        if (rgid != (gid_t) -1 ||
 602            (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 603                new->sgid = new->egid;
 604        new->fsgid = new->egid;
 605
 606        return commit_creds(new);
 607
 608error:
 609        abort_creds(new);
 610        return retval;
 611}
 612
 613/*
 614 * setgid() is implemented like SysV w/ SAVED_IDS 
 615 *
 616 * SMP: Same implicit races as above.
 617 */
 618SYSCALL_DEFINE1(setgid, gid_t, gid)
 619{
 620        struct user_namespace *ns = current_user_ns();
 621        const struct cred *old;
 622        struct cred *new;
 623        int retval;
 624        kgid_t kgid;
 625
 626        kgid = make_kgid(ns, gid);
 627        if (!gid_valid(kgid))
 628                return -EINVAL;
 629
 630        new = prepare_creds();
 631        if (!new)
 632                return -ENOMEM;
 633        old = current_cred();
 634
 635        retval = -EPERM;
 636        if (nsown_capable(CAP_SETGID))
 637                new->gid = new->egid = new->sgid = new->fsgid = kgid;
 638        else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 639                new->egid = new->fsgid = kgid;
 640        else
 641                goto error;
 642
 643        return commit_creds(new);
 644
 645error:
 646        abort_creds(new);
 647        return retval;
 648}
 649
 650/*
 651 * change the user struct in a credentials set to match the new UID
 652 */
 653static int set_user(struct cred *new)
 654{
 655        struct user_struct *new_user;
 656
 657        new_user = alloc_uid(new->uid);
 658        if (!new_user)
 659                return -EAGAIN;
 660
 661        /*
 662         * We don't fail in case of NPROC limit excess here because too many
 663         * poorly written programs don't check set*uid() return code, assuming
 664         * it never fails if called by root.  We may still enforce NPROC limit
 665         * for programs doing set*uid()+execve() by harmlessly deferring the
 666         * failure to the execve() stage.
 667         */
 668        if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 669                        new_user != INIT_USER)
 670                current->flags |= PF_NPROC_EXCEEDED;
 671        else
 672                current->flags &= ~PF_NPROC_EXCEEDED;
 673
 674        free_uid(new->user);
 675        new->user = new_user;
 676        return 0;
 677}
 678
 679/*
 680 * Unprivileged users may change the real uid to the effective uid
 681 * or vice versa.  (BSD-style)
 682 *
 683 * If you set the real uid at all, or set the effective uid to a value not
 684 * equal to the real uid, then the saved uid is set to the new effective uid.
 685 *
 686 * This makes it possible for a setuid program to completely drop its
 687 * privileges, which is often a useful assertion to make when you are doing
 688 * a security audit over a program.
 689 *
 690 * The general idea is that a program which uses just setreuid() will be
 691 * 100% compatible with BSD.  A program which uses just setuid() will be
 692 * 100% compatible with POSIX with saved IDs. 
 693 */
 694SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 695{
 696        struct user_namespace *ns = current_user_ns();
 697        const struct cred *old;
 698        struct cred *new;
 699        int retval;
 700        kuid_t kruid, keuid;
 701
 702        kruid = make_kuid(ns, ruid);
 703        keuid = make_kuid(ns, euid);
 704
 705        if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 706                return -EINVAL;
 707        if ((euid != (uid_t) -1) && !uid_valid(keuid))
 708                return -EINVAL;
 709
 710        new = prepare_creds();
 711        if (!new)
 712                return -ENOMEM;
 713        old = current_cred();
 714
 715        retval = -EPERM;
 716        if (ruid != (uid_t) -1) {
 717                new->uid = kruid;
 718                if (!uid_eq(old->uid, kruid) &&
 719                    !uid_eq(old->euid, kruid) &&
 720                    !nsown_capable(CAP_SETUID))
 721                        goto error;
 722        }
 723
 724        if (euid != (uid_t) -1) {
 725                new->euid = keuid;
 726                if (!uid_eq(old->uid, keuid) &&
 727                    !uid_eq(old->euid, keuid) &&
 728                    !uid_eq(old->suid, keuid) &&
 729                    !nsown_capable(CAP_SETUID))
 730                        goto error;
 731        }
 732
 733        if (!uid_eq(new->uid, old->uid)) {
 734                retval = set_user(new);
 735                if (retval < 0)
 736                        goto error;
 737        }
 738        if (ruid != (uid_t) -1 ||
 739            (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 740                new->suid = new->euid;
 741        new->fsuid = new->euid;
 742
 743        retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 744        if (retval < 0)
 745                goto error;
 746
 747        return commit_creds(new);
 748
 749error:
 750        abort_creds(new);
 751        return retval;
 752}
 753                
 754/*
 755 * setuid() is implemented like SysV with SAVED_IDS 
 756 * 
 757 * Note that SAVED_ID's is deficient in that a setuid root program
 758 * like sendmail, for example, cannot set its uid to be a normal 
 759 * user and then switch back, because if you're root, setuid() sets
 760 * the saved uid too.  If you don't like this, blame the bright people
 761 * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 762 * will allow a root program to temporarily drop privileges and be able to
 763 * regain them by swapping the real and effective uid.  
 764 */
 765SYSCALL_DEFINE1(setuid, uid_t, uid)
 766{
 767        struct user_namespace *ns = current_user_ns();
 768        const struct cred *old;
 769        struct cred *new;
 770        int retval;
 771        kuid_t kuid;
 772
 773        kuid = make_kuid(ns, uid);
 774        if (!uid_valid(kuid))
 775                return -EINVAL;
 776
 777        new = prepare_creds();
 778        if (!new)
 779                return -ENOMEM;
 780        old = current_cred();
 781
 782        retval = -EPERM;
 783        if (nsown_capable(CAP_SETUID)) {
 784                new->suid = new->uid = kuid;
 785                if (!uid_eq(kuid, old->uid)) {
 786                        retval = set_user(new);
 787                        if (retval < 0)
 788                                goto error;
 789                }
 790        } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 791                goto error;
 792        }
 793
 794        new->fsuid = new->euid = kuid;
 795
 796        retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 797        if (retval < 0)
 798                goto error;
 799
 800        return commit_creds(new);
 801
 802error:
 803        abort_creds(new);
 804        return retval;
 805}
 806
 807
 808/*
 809 * This function implements a generic ability to update ruid, euid,
 810 * and suid.  This allows you to implement the 4.4 compatible seteuid().
 811 */
 812SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 813{
 814        struct user_namespace *ns = current_user_ns();
 815        const struct cred *old;
 816        struct cred *new;
 817        int retval;
 818        kuid_t kruid, keuid, ksuid;
 819
 820        kruid = make_kuid(ns, ruid);
 821        keuid = make_kuid(ns, euid);
 822        ksuid = make_kuid(ns, suid);
 823
 824        if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 825                return -EINVAL;
 826
 827        if ((euid != (uid_t) -1) && !uid_valid(keuid))
 828                return -EINVAL;
 829
 830        if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 831                return -EINVAL;
 832
 833        new = prepare_creds();
 834        if (!new)
 835                return -ENOMEM;
 836
 837        old = current_cred();
 838
 839        retval = -EPERM;
 840        if (!nsown_capable(CAP_SETUID)) {
 841                if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 842                    !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 843                        goto error;
 844                if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 845                    !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 846                        goto error;
 847                if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 848                    !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 849                        goto error;
 850        }
 851
 852        if (ruid != (uid_t) -1) {
 853                new->uid = kruid;
 854                if (!uid_eq(kruid, old->uid)) {
 855                        retval = set_user(new);
 856                        if (retval < 0)
 857                                goto error;
 858                }
 859        }
 860        if (euid != (uid_t) -1)
 861                new->euid = keuid;
 862        if (suid != (uid_t) -1)
 863                new->suid = ksuid;
 864        new->fsuid = new->euid;
 865
 866        retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 867        if (retval < 0)
 868                goto error;
 869
 870        return commit_creds(new);
 871
 872error:
 873        abort_creds(new);
 874        return retval;
 875}
 876
 877SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 878{
 879        const struct cred *cred = current_cred();
 880        int retval;
 881        uid_t ruid, euid, suid;
 882
 883        ruid = from_kuid_munged(cred->user_ns, cred->uid);
 884        euid = from_kuid_munged(cred->user_ns, cred->euid);
 885        suid = from_kuid_munged(cred->user_ns, cred->suid);
 886
 887        if (!(retval   = put_user(ruid, ruidp)) &&
 888            !(retval   = put_user(euid, euidp)))
 889                retval = put_user(suid, suidp);
 890
 891        return retval;
 892}
 893
 894/*
 895 * Same as above, but for rgid, egid, sgid.
 896 */
 897SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 898{
 899        struct user_namespace *ns = current_user_ns();
 900        const struct cred *old;
 901        struct cred *new;
 902        int retval;
 903        kgid_t krgid, kegid, ksgid;
 904
 905        krgid = make_kgid(ns, rgid);
 906        kegid = make_kgid(ns, egid);
 907        ksgid = make_kgid(ns, sgid);
 908
 909        if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 910                return -EINVAL;
 911        if ((egid != (gid_t) -1) && !gid_valid(kegid))
 912                return -EINVAL;
 913        if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 914                return -EINVAL;
 915
 916        new = prepare_creds();
 917        if (!new)
 918                return -ENOMEM;
 919        old = current_cred();
 920
 921        retval = -EPERM;
 922        if (!nsown_capable(CAP_SETGID)) {
 923                if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 924                    !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 925                        goto error;
 926                if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 927                    !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 928                        goto error;
 929                if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 930                    !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 931                        goto error;
 932        }
 933
 934        if (rgid != (gid_t) -1)
 935                new->gid = krgid;
 936        if (egid != (gid_t) -1)
 937                new->egid = kegid;
 938        if (sgid != (gid_t) -1)
 939                new->sgid = ksgid;
 940        new->fsgid = new->egid;
 941
 942        return commit_creds(new);
 943
 944error:
 945        abort_creds(new);
 946        return retval;
 947}
 948
 949SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 950{
 951        const struct cred *cred = current_cred();
 952        int retval;
 953        gid_t rgid, egid, sgid;
 954
 955        rgid = from_kgid_munged(cred->user_ns, cred->gid);
 956        egid = from_kgid_munged(cred->user_ns, cred->egid);
 957        sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 958
 959        if (!(retval   = put_user(rgid, rgidp)) &&
 960            !(retval   = put_user(egid, egidp)))
 961                retval = put_user(sgid, sgidp);
 962
 963        return retval;
 964}
 965
 966
 967/*
 968 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 969 * is used for "access()" and for the NFS daemon (letting nfsd stay at
 970 * whatever uid it wants to). It normally shadows "euid", except when
 971 * explicitly set by setfsuid() or for access..
 972 */
 973SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 974{
 975        const struct cred *old;
 976        struct cred *new;
 977        uid_t old_fsuid;
 978        kuid_t kuid;
 979
 980        old = current_cred();
 981        old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 982
 983        kuid = make_kuid(old->user_ns, uid);
 984        if (!uid_valid(kuid))
 985                return old_fsuid;
 986
 987        new = prepare_creds();
 988        if (!new)
 989                return old_fsuid;
 990
 991        if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 992            uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 993            nsown_capable(CAP_SETUID)) {
 994                if (!uid_eq(kuid, old->fsuid)) {
 995                        new->fsuid = kuid;
 996                        if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 997                                goto change_okay;
 998                }
 999        }
1000
1001        abort_creds(new);
1002        return old_fsuid;
1003
1004change_okay:
1005        commit_creds(new);
1006        return old_fsuid;
1007}
1008
1009/*
1010 * Samma på svenska..
1011 */
1012SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1013{
1014        const struct cred *old;
1015        struct cred *new;
1016        gid_t old_fsgid;
1017        kgid_t kgid;
1018
1019        old = current_cred();
1020        old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1021
1022        kgid = make_kgid(old->user_ns, gid);
1023        if (!gid_valid(kgid))
1024                return old_fsgid;
1025
1026        new = prepare_creds();
1027        if (!new)
1028                return old_fsgid;
1029
1030        if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
1031            gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1032            nsown_capable(CAP_SETGID)) {
1033                if (!gid_eq(kgid, old->fsgid)) {
1034                        new->fsgid = kgid;
1035                        goto change_okay;
1036                }
1037        }
1038
1039        abort_creds(new);
1040        return old_fsgid;
1041
1042change_okay:
1043        commit_creds(new);
1044        return old_fsgid;
1045}
1046
1047void do_sys_times(struct tms *tms)
1048{
1049        cputime_t tgutime, tgstime, cutime, cstime;
1050
1051        spin_lock_irq(&current->sighand->siglock);
1052        thread_group_cputime_adjusted(current, &tgutime, &tgstime);
1053        cutime = current->signal->cutime;
1054        cstime = current->signal->cstime;
1055        spin_unlock_irq(&current->sighand->siglock);
1056        tms->tms_utime = cputime_to_clock_t(tgutime);
1057        tms->tms_stime = cputime_to_clock_t(tgstime);
1058        tms->tms_cutime = cputime_to_clock_t(cutime);
1059        tms->tms_cstime = cputime_to_clock_t(cstime);
1060}
1061
1062SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1063{
1064        if (tbuf) {
1065                struct tms tmp;
1066
1067                do_sys_times(&tmp);
1068                if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1069                        return -EFAULT;
1070        }
1071        force_successful_syscall_return();
1072        return (long) jiffies_64_to_clock_t(get_jiffies_64());
1073}
1074
1075/*
1076 * This needs some heavy checking ...
1077 * I just haven't the stomach for it. I also don't fully
1078 * understand sessions/pgrp etc. Let somebody who does explain it.
1079 *
1080 * OK, I think I have the protection semantics right.... this is really
1081 * only important on a multi-user system anyway, to make sure one user
1082 * can't send a signal to a process owned by another.  -TYT, 12/12/91
1083 *
1084 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1085 * LBT 04.03.94
1086 */
1087SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1088{
1089        struct task_struct *p;
1090        struct task_struct *group_leader = current->group_leader;
1091        struct pid *pgrp;
1092        int err;
1093
1094        if (!pid)
1095                pid = task_pid_vnr(group_leader);
1096        if (!pgid)
1097                pgid = pid;
1098        if (pgid < 0)
1099                return -EINVAL;
1100        rcu_read_lock();
1101
1102        /* From this point forward we keep holding onto the tasklist lock
1103         * so that our parent does not change from under us. -DaveM
1104         */
1105        write_lock_irq(&tasklist_lock);
1106
1107        err = -ESRCH;
1108        p = find_task_by_vpid(pid);
1109        if (!p)
1110                goto out;
1111
1112        err = -EINVAL;
1113        if (!thread_group_leader(p))
1114                goto out;
1115
1116        if (same_thread_group(p->real_parent, group_leader)) {
1117                err = -EPERM;
1118                if (task_session(p) != task_session(group_leader))
1119                        goto out;
1120                err = -EACCES;
1121                if (p->did_exec)
1122                        goto out;
1123        } else {
1124                err = -ESRCH;
1125                if (p != group_leader)
1126                        goto out;
1127        }
1128
1129        err = -EPERM;
1130        if (p->signal->leader)
1131                goto out;
1132
1133        pgrp = task_pid(p);
1134        if (pgid != pid) {
1135                struct task_struct *g;
1136
1137                pgrp = find_vpid(pgid);
1138                g = pid_task(pgrp, PIDTYPE_PGID);
1139                if (!g || task_session(g) != task_session(group_leader))
1140                        goto out;
1141        }
1142
1143        err = security_task_setpgid(p, pgid);
1144        if (err)
1145                goto out;
1146
1147        if (task_pgrp(p) != pgrp)
1148                change_pid(p, PIDTYPE_PGID, pgrp);
1149
1150        err = 0;
1151out:
1152        /* All paths lead to here, thus we are safe. -DaveM */
1153        write_unlock_irq(&tasklist_lock);
1154        rcu_read_unlock();
1155        return err;
1156}
1157
1158SYSCALL_DEFINE1(getpgid, pid_t, pid)
1159{
1160        struct task_struct *p;
1161        struct pid *grp;
1162        int retval;
1163
1164        rcu_read_lock();
1165        if (!pid)
1166                grp = task_pgrp(current);
1167        else {
1168                retval = -ESRCH;
1169                p = find_task_by_vpid(pid);
1170                if (!p)
1171                        goto out;
1172                grp = task_pgrp(p);
1173                if (!grp)
1174                        goto out;
1175
1176                retval = security_task_getpgid(p);
1177                if (retval)
1178                        goto out;
1179        }
1180        retval = pid_vnr(grp);
1181out:
1182        rcu_read_unlock();
1183        return retval;
1184}
1185
1186#ifdef __ARCH_WANT_SYS_GETPGRP
1187
1188SYSCALL_DEFINE0(getpgrp)
1189{
1190        return sys_getpgid(0);
1191}
1192
1193#endif
1194
1195SYSCALL_DEFINE1(getsid, pid_t, pid)
1196{
1197        struct task_struct *p;
1198        struct pid *sid;
1199        int retval;
1200
1201        rcu_read_lock();
1202        if (!pid)
1203                sid = task_session(current);
1204        else {
1205                retval = -ESRCH;
1206                p = find_task_by_vpid(pid);
1207                if (!p)
1208                        goto out;
1209                sid = task_session(p);
1210                if (!sid)
1211                        goto out;
1212
1213                retval = security_task_getsid(p);
1214                if (retval)
1215                        goto out;
1216        }
1217        retval = pid_vnr(sid);
1218out:
1219        rcu_read_unlock();
1220        return retval;
1221}
1222
1223SYSCALL_DEFINE0(setsid)
1224{
1225        struct task_struct *group_leader = current->group_leader;
1226        struct pid *sid = task_pid(group_leader);
1227        pid_t session = pid_vnr(sid);
1228        int err = -EPERM;
1229
1230        write_lock_irq(&tasklist_lock);
1231        /* Fail if I am already a session leader */
1232        if (group_leader->signal->leader)
1233                goto out;
1234
1235        /* Fail if a process group id already exists that equals the
1236         * proposed session id.
1237         */
1238        if (pid_task(sid, PIDTYPE_PGID))
1239                goto out;
1240
1241        group_leader->signal->leader = 1;
1242        __set_special_pids(sid);
1243
1244        proc_clear_tty(group_leader);
1245
1246        err = session;
1247out:
1248        write_unlock_irq(&tasklist_lock);
1249        if (err > 0) {
1250                proc_sid_connector(group_leader);
1251                sched_autogroup_create_attach(group_leader);
1252        }
1253        return err;
1254}
1255
1256DECLARE_RWSEM(uts_sem);
1257
1258#ifdef COMPAT_UTS_MACHINE
1259#define override_architecture(name) \
1260        (personality(current->personality) == PER_LINUX32 && \
1261         copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1262                      sizeof(COMPAT_UTS_MACHINE)))
1263#else
1264#define override_architecture(name)     0
1265#endif
1266
1267/*
1268 * Work around broken programs that cannot handle "Linux 3.0".
1269 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1270 */
1271static int override_release(char __user *release, size_t len)
1272{
1273        int ret = 0;
1274
1275        if (current->personality & UNAME26) {
1276                const char *rest = UTS_RELEASE;
1277                char buf[65] = { 0 };
1278                int ndots = 0;
1279                unsigned v;
1280                size_t copy;
1281
1282                while (*rest) {
1283                        if (*rest == '.' && ++ndots >= 3)
1284                                break;
1285                        if (!isdigit(*rest) && *rest != '.')
1286                                break;
1287                        rest++;
1288                }
1289                v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1290                copy = clamp_t(size_t, len, 1, sizeof(buf));
1291                copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1292                ret = copy_to_user(release, buf, copy + 1);
1293        }
1294        return ret;
1295}
1296
1297SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1298{
1299        int errno = 0;
1300
1301        down_read(&uts_sem);
1302        if (copy_to_user(name, utsname(), sizeof *name))
1303                errno = -EFAULT;
1304        up_read(&uts_sem);
1305
1306        if (!errno && override_release(name->release, sizeof(name->release)))
1307                errno = -EFAULT;
1308        if (!errno && override_architecture(name))
1309                errno = -EFAULT;
1310        return errno;
1311}
1312
1313#ifdef __ARCH_WANT_SYS_OLD_UNAME
1314/*
1315 * Old cruft
1316 */
1317SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1318{
1319        int error = 0;
1320
1321        if (!name)
1322                return -EFAULT;
1323
1324        down_read(&uts_sem);
1325        if (copy_to_user(name, utsname(), sizeof(*name)))
1326                error = -EFAULT;
1327        up_read(&uts_sem);
1328
1329        if (!error && override_release(name->release, sizeof(name->release)))
1330                error = -EFAULT;
1331        if (!error && override_architecture(name))
1332                error = -EFAULT;
1333        return error;
1334}
1335
1336SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1337{
1338        int error;
1339
1340        if (!name)
1341                return -EFAULT;
1342        if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1343                return -EFAULT;
1344
1345        down_read(&uts_sem);
1346        error = __copy_to_user(&name->sysname, &utsname()->sysname,
1347                               __OLD_UTS_LEN);
1348        error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1349        error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1350                                __OLD_UTS_LEN);
1351        error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1352        error |= __copy_to_user(&name->release, &utsname()->release,
1353                                __OLD_UTS_LEN);
1354        error |= __put_user(0, name->release + __OLD_UTS_LEN);
1355        error |= __copy_to_user(&name->version, &utsname()->version,
1356                                __OLD_UTS_LEN);
1357        error |= __put_user(0, name->version + __OLD_UTS_LEN);
1358        error |= __copy_to_user(&name->machine, &utsname()->machine,
1359                                __OLD_UTS_LEN);
1360        error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1361        up_read(&uts_sem);
1362
1363        if (!error && override_architecture(name))
1364                error = -EFAULT;
1365        if (!error && override_release(name->release, sizeof(name->release)))
1366                error = -EFAULT;
1367        return error ? -EFAULT : 0;
1368}
1369#endif
1370
1371SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1372{
1373        int errno;
1374        char tmp[__NEW_UTS_LEN];
1375
1376        if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1377                return -EPERM;
1378
1379        if (len < 0 || len > __NEW_UTS_LEN)
1380                return -EINVAL;
1381        down_write(&uts_sem);
1382        errno = -EFAULT;
1383        if (!copy_from_user(tmp, name, len)) {
1384                struct new_utsname *u = utsname();
1385
1386                memcpy(u->nodename, tmp, len);
1387                memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1388                errno = 0;
1389                uts_proc_notify(UTS_PROC_HOSTNAME);
1390        }
1391        up_write(&uts_sem);
1392        return errno;
1393}
1394
1395#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1396
1397SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1398{
1399        int i, errno;
1400        struct new_utsname *u;
1401
1402        if (len < 0)
1403                return -EINVAL;
1404        down_read(&uts_sem);
1405        u = utsname();
1406        i = 1 + strlen(u->nodename);
1407        if (i > len)
1408                i = len;
1409        errno = 0;
1410        if (copy_to_user(name, u->nodename, i))
1411                errno = -EFAULT;
1412        up_read(&uts_sem);
1413        return errno;
1414}
1415
1416#endif
1417
1418/*
1419 * Only setdomainname; getdomainname can be implemented by calling
1420 * uname()
1421 */
1422SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1423{
1424        int errno;
1425        char tmp[__NEW_UTS_LEN];
1426
1427        if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1428                return -EPERM;
1429        if (len < 0 || len > __NEW_UTS_LEN)
1430                return -EINVAL;
1431
1432        down_write(&uts_sem);
1433        errno = -EFAULT;
1434        if (!copy_from_user(tmp, name, len)) {
1435                struct new_utsname *u = utsname();
1436
1437                memcpy(u->domainname, tmp, len);
1438                memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1439                errno = 0;
1440                uts_proc_notify(UTS_PROC_DOMAINNAME);
1441        }
1442        up_write(&uts_sem);
1443        return errno;
1444}
1445
1446SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1447{
1448        struct rlimit value;
1449        int ret;
1450
1451        ret = do_prlimit(current, resource, NULL, &value);
1452        if (!ret)
1453                ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1454
1455        return ret;
1456}
1457
1458#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1459
1460/*
1461 *      Back compatibility for getrlimit. Needed for some apps.
1462 */
1463 
1464SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1465                struct rlimit __user *, rlim)
1466{
1467        struct rlimit x;
1468        if (resource >= RLIM_NLIMITS)
1469                return -EINVAL;
1470
1471        task_lock(current->group_leader);
1472        x = current->signal->rlim[resource];
1473        task_unlock(current->group_leader);
1474        if (x.rlim_cur > 0x7FFFFFFF)
1475                x.rlim_cur = 0x7FFFFFFF;
1476        if (x.rlim_max > 0x7FFFFFFF)
1477                x.rlim_max = 0x7FFFFFFF;
1478        return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1479}
1480
1481#endif
1482
1483static inline bool rlim64_is_infinity(__u64 rlim64)
1484{
1485#if BITS_PER_LONG < 64
1486        return rlim64 >= ULONG_MAX;
1487#else
1488        return rlim64 == RLIM64_INFINITY;
1489#endif
1490}
1491
1492static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1493{
1494        if (rlim->rlim_cur == RLIM_INFINITY)
1495                rlim64->rlim_cur = RLIM64_INFINITY;
1496        else
1497                rlim64->rlim_cur = rlim->rlim_cur;
1498        if (rlim->rlim_max == RLIM_INFINITY)
1499                rlim64->rlim_max = RLIM64_INFINITY;
1500        else
1501                rlim64->rlim_max = rlim->rlim_max;
1502}
1503
1504static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1505{
1506        if (rlim64_is_infinity(rlim64->rlim_cur))
1507                rlim->rlim_cur = RLIM_INFINITY;
1508        else
1509                rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1510        if (rlim64_is_infinity(rlim64->rlim_max))
1511                rlim->rlim_max = RLIM_INFINITY;
1512        else
1513                rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1514}
1515
1516/* make sure you are allowed to change @tsk limits before calling this */
1517int do_prlimit(struct task_struct *tsk, unsigned int resource,
1518                struct rlimit *new_rlim, struct rlimit *old_rlim)
1519{
1520        struct rlimit *rlim;
1521        int retval = 0;
1522
1523        if (resource >= RLIM_NLIMITS)
1524                return -EINVAL;
1525        if (new_rlim) {
1526                if (new_rlim->rlim_cur > new_rlim->rlim_max)
1527                        return -EINVAL;
1528                if (resource == RLIMIT_NOFILE &&
1529                                new_rlim->rlim_max > sysctl_nr_open)
1530                        return -EPERM;
1531        }
1532
1533        /* protect tsk->signal and tsk->sighand from disappearing */
1534        read_lock(&tasklist_lock);
1535        if (!tsk->sighand) {
1536                retval = -ESRCH;
1537                goto out;
1538        }
1539
1540        rlim = tsk->signal->rlim + resource;
1541        task_lock(tsk->group_leader);
1542        if (new_rlim) {
1543                /* Keep the capable check against init_user_ns until
1544                   cgroups can contain all limits */
1545                if (new_rlim->rlim_max > rlim->rlim_max &&
1546                                !capable(CAP_SYS_RESOURCE))
1547                        retval = -EPERM;
1548                if (!retval)
1549                        retval = security_task_setrlimit(tsk->group_leader,
1550                                        resource, new_rlim);
1551                if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1552                        /*
1553                         * The caller is asking for an immediate RLIMIT_CPU
1554                         * expiry.  But we use the zero value to mean "it was
1555                         * never set".  So let's cheat and make it one second
1556                         * instead
1557                         */
1558                        new_rlim->rlim_cur = 1;
1559                }
1560        }
1561        if (!retval) {
1562                if (old_rlim)
1563                        *old_rlim = *rlim;
1564                if (new_rlim)
1565                        *rlim = *new_rlim;
1566        }
1567        task_unlock(tsk->group_leader);
1568
1569        /*
1570         * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1571         * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1572         * very long-standing error, and fixing it now risks breakage of
1573         * applications, so we live with it
1574         */
1575         if (!retval && new_rlim && resource == RLIMIT_CPU &&
1576                         new_rlim->rlim_cur != RLIM_INFINITY)
1577                update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1578out:
1579        read_unlock(&tasklist_lock);
1580        return retval;
1581}
1582
1583/* rcu lock must be held */
1584static int check_prlimit_permission(struct task_struct *task)
1585{
1586        const struct cred *cred = current_cred(), *tcred;
1587
1588        if (current == task)
1589                return 0;
1590
1591        tcred = __task_cred(task);
1592        if (uid_eq(cred->uid, tcred->euid) &&
1593            uid_eq(cred->uid, tcred->suid) &&
1594            uid_eq(cred->uid, tcred->uid)  &&
1595            gid_eq(cred->gid, tcred->egid) &&
1596            gid_eq(cred->gid, tcred->sgid) &&
1597            gid_eq(cred->gid, tcred->gid))
1598                return 0;
1599        if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1600                return 0;
1601
1602        return -EPERM;
1603}
1604
1605SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1606                const struct rlimit64 __user *, new_rlim,
1607                struct rlimit64 __user *, old_rlim)
1608{
1609        struct rlimit64 old64, new64;
1610        struct rlimit old, new;
1611        struct task_struct *tsk;
1612        int ret;
1613
1614        if (new_rlim) {
1615                if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1616                        return -EFAULT;
1617                rlim64_to_rlim(&new64, &new);
1618        }
1619
1620        rcu_read_lock();
1621        tsk = pid ? find_task_by_vpid(pid) : current;
1622        if (!tsk) {
1623                rcu_read_unlock();
1624                return -ESRCH;
1625        }
1626        ret = check_prlimit_permission(tsk);
1627        if (ret) {
1628                rcu_read_unlock();
1629                return ret;
1630        }
1631        get_task_struct(tsk);
1632        rcu_read_unlock();
1633
1634        ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1635                        old_rlim ? &old : NULL);
1636
1637        if (!ret && old_rlim) {
1638                rlim_to_rlim64(&old, &old64);
1639                if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1640                        ret = -EFAULT;
1641        }
1642
1643        put_task_struct(tsk);
1644        return ret;
1645}
1646
1647SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1648{
1649        struct rlimit new_rlim;
1650
1651        if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1652                return -EFAULT;
1653        return do_prlimit(current, resource, &new_rlim, NULL);
1654}
1655
1656/*
1657 * It would make sense to put struct rusage in the task_struct,
1658 * except that would make the task_struct be *really big*.  After
1659 * task_struct gets moved into malloc'ed memory, it would
1660 * make sense to do this.  It will make moving the rest of the information
1661 * a lot simpler!  (Which we're not doing right now because we're not
1662 * measuring them yet).
1663 *
1664 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1665 * races with threads incrementing their own counters.  But since word
1666 * reads are atomic, we either get new values or old values and we don't
1667 * care which for the sums.  We always take the siglock to protect reading
1668 * the c* fields from p->signal from races with exit.c updating those
1669 * fields when reaping, so a sample either gets all the additions of a
1670 * given child after it's reaped, or none so this sample is before reaping.
1671 *
1672 * Locking:
1673 * We need to take the siglock for CHILDEREN, SELF and BOTH
1674 * for  the cases current multithreaded, non-current single threaded
1675 * non-current multithreaded.  Thread traversal is now safe with
1676 * the siglock held.
1677 * Strictly speaking, we donot need to take the siglock if we are current and
1678 * single threaded,  as no one else can take our signal_struct away, no one
1679 * else can  reap the  children to update signal->c* counters, and no one else
1680 * can race with the signal-> fields. If we do not take any lock, the
1681 * signal-> fields could be read out of order while another thread was just
1682 * exiting. So we should  place a read memory barrier when we avoid the lock.
1683 * On the writer side,  write memory barrier is implied in  __exit_signal
1684 * as __exit_signal releases  the siglock spinlock after updating the signal->
1685 * fields. But we don't do this yet to keep things simple.
1686 *
1687 */
1688
1689static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1690{
1691        r->ru_nvcsw += t->nvcsw;
1692        r->ru_nivcsw += t->nivcsw;
1693        r->ru_minflt += t->min_flt;
1694        r->ru_majflt += t->maj_flt;
1695        r->ru_inblock += task_io_get_inblock(t);
1696        r->ru_oublock += task_io_get_oublock(t);
1697}
1698
1699static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1700{
1701        struct task_struct *t;
1702        unsigned long flags;
1703        cputime_t tgutime, tgstime, utime, stime;
1704        unsigned long maxrss = 0;
1705
1706        memset((char *) r, 0, sizeof *r);
1707        utime = stime = 0;
1708
1709        if (who == RUSAGE_THREAD) {
1710                task_cputime_adjusted(current, &utime, &stime);
1711                accumulate_thread_rusage(p, r);
1712                maxrss = p->signal->maxrss;
1713                goto out;
1714        }
1715
1716        if (!lock_task_sighand(p, &flags))
1717                return;
1718
1719        switch (who) {
1720                case RUSAGE_BOTH:
1721                case RUSAGE_CHILDREN:
1722                        utime = p->signal->cutime;
1723                        stime = p->signal->cstime;
1724                        r->ru_nvcsw = p->signal->cnvcsw;
1725                        r->ru_nivcsw = p->signal->cnivcsw;
1726                        r->ru_minflt = p->signal->cmin_flt;
1727                        r->ru_majflt = p->signal->cmaj_flt;
1728                        r->ru_inblock = p->signal->cinblock;
1729                        r->ru_oublock = p->signal->coublock;
1730                        maxrss = p->signal->cmaxrss;
1731
1732                        if (who == RUSAGE_CHILDREN)
1733                                break;
1734
1735                case RUSAGE_SELF:
1736                        thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1737                        utime += tgutime;
1738                        stime += tgstime;
1739                        r->ru_nvcsw += p->signal->nvcsw;
1740                        r->ru_nivcsw += p->signal->nivcsw;
1741                        r->ru_minflt += p->signal->min_flt;
1742                        r->ru_majflt += p->signal->maj_flt;
1743                        r->ru_inblock += p->signal->inblock;
1744                        r->ru_oublock += p->signal->oublock;
1745                        if (maxrss < p->signal->maxrss)
1746                                maxrss = p->signal->maxrss;
1747                        t = p;
1748                        do {
1749                                accumulate_thread_rusage(t, r);
1750                                t = next_thread(t);
1751                        } while (t != p);
1752                        break;
1753
1754                default:
1755                        BUG();
1756        }
1757        unlock_task_sighand(p, &flags);
1758
1759out:
1760        cputime_to_timeval(utime, &r->ru_utime);
1761        cputime_to_timeval(stime, &r->ru_stime);
1762
1763        if (who != RUSAGE_CHILDREN) {
1764                struct mm_struct *mm = get_task_mm(p);
1765                if (mm) {
1766                        setmax_mm_hiwater_rss(&maxrss, mm);
1767                        mmput(mm);
1768                }
1769        }
1770        r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1771}
1772
1773int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1774{
1775        struct rusage r;
1776        k_getrusage(p, who, &r);
1777        return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1778}
1779
1780SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1781{
1782        if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1783            who != RUSAGE_THREAD)
1784                return -EINVAL;
1785        return getrusage(current, who, ru);
1786}
1787
1788SYSCALL_DEFINE1(umask, int, mask)
1789{
1790        mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1791        return mask;
1792}
1793
1794#ifdef CONFIG_CHECKPOINT_RESTORE
1795static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1796{
1797        struct fd exe;
1798        struct inode *inode;
1799        int err;
1800
1801        exe = fdget(fd);
1802        if (!exe.file)
1803                return -EBADF;
1804
1805        inode = file_inode(exe.file);
1806
1807        /*
1808         * Because the original mm->exe_file points to executable file, make
1809         * sure that this one is executable as well, to avoid breaking an
1810         * overall picture.
1811         */
1812        err = -EACCES;
1813        if (!S_ISREG(inode->i_mode)     ||
1814            exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1815                goto exit;
1816
1817        err = inode_permission(inode, MAY_EXEC);
1818        if (err)
1819                goto exit;
1820
1821        down_write(&mm->mmap_sem);
1822
1823        /*
1824         * Forbid mm->exe_file change if old file still mapped.
1825         */
1826        err = -EBUSY;
1827        if (mm->exe_file) {
1828                struct vm_area_struct *vma;
1829
1830                for (vma = mm->mmap; vma; vma = vma->vm_next)
1831                        if (vma->vm_file &&
1832                            path_equal(&vma->vm_file->f_path,
1833                                       &mm->exe_file->f_path))
1834                                goto exit_unlock;
1835        }
1836
1837        /*
1838         * The symlink can be changed only once, just to disallow arbitrary
1839         * transitions malicious software might bring in. This means one
1840         * could make a snapshot over all processes running and monitor
1841         * /proc/pid/exe changes to notice unusual activity if needed.
1842         */
1843        err = -EPERM;
1844        if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1845                goto exit_unlock;
1846
1847        err = 0;
1848        set_mm_exe_file(mm, exe.file);  /* this grabs a reference to exe.file */
1849exit_unlock:
1850        up_write(&mm->mmap_sem);
1851
1852exit:
1853        fdput(exe);
1854        return err;
1855}
1856
1857static int prctl_set_mm(int opt, unsigned long addr,
1858                        unsigned long arg4, unsigned long arg5)
1859{
1860        unsigned long rlim = rlimit(RLIMIT_DATA);
1861        struct mm_struct *mm = current->mm;
1862        struct vm_area_struct *vma;
1863        int error;
1864
1865        if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1866                return -EINVAL;
1867
1868        if (!capable(CAP_SYS_RESOURCE))
1869                return -EPERM;
1870
1871        if (opt == PR_SET_MM_EXE_FILE)
1872                return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1873
1874        if (addr >= TASK_SIZE || addr < mmap_min_addr)
1875                return -EINVAL;
1876
1877        error = -EINVAL;
1878
1879        down_read(&mm->mmap_sem);
1880        vma = find_vma(mm, addr);
1881
1882        switch (opt) {
1883        case PR_SET_MM_START_CODE:
1884                mm->start_code = addr;
1885                break;
1886        case PR_SET_MM_END_CODE:
1887                mm->end_code = addr;
1888                break;
1889        case PR_SET_MM_START_DATA:
1890                mm->start_data = addr;
1891                break;
1892        case PR_SET_MM_END_DATA:
1893                mm->end_data = addr;
1894                break;
1895
1896        case PR_SET_MM_START_BRK:
1897                if (addr <= mm->end_data)
1898                        goto out;
1899
1900                if (rlim < RLIM_INFINITY &&
1901                    (mm->brk - addr) +
1902                    (mm->end_data - mm->start_data) > rlim)
1903                        goto out;
1904
1905                mm->start_brk = addr;
1906                break;
1907
1908        case PR_SET_MM_BRK:
1909                if (addr <= mm->end_data)
1910                        goto out;
1911
1912                if (rlim < RLIM_INFINITY &&
1913                    (addr - mm->start_brk) +
1914                    (mm->end_data - mm->start_data) > rlim)
1915                        goto out;
1916
1917                mm->brk = addr;
1918                break;
1919
1920        /*
1921         * If command line arguments and environment
1922         * are placed somewhere else on stack, we can
1923         * set them up here, ARG_START/END to setup
1924         * command line argumets and ENV_START/END
1925         * for environment.
1926         */
1927        case PR_SET_MM_START_STACK:
1928        case PR_SET_MM_ARG_START:
1929        case PR_SET_MM_ARG_END:
1930        case PR_SET_MM_ENV_START:
1931        case PR_SET_MM_ENV_END:
1932                if (!vma) {
1933                        error = -EFAULT;
1934                        goto out;
1935                }
1936                if (opt == PR_SET_MM_START_STACK)
1937                        mm->start_stack = addr;
1938                else if (opt == PR_SET_MM_ARG_START)
1939                        mm->arg_start = addr;
1940                else if (opt == PR_SET_MM_ARG_END)
1941                        mm->arg_end = addr;
1942                else if (opt == PR_SET_MM_ENV_START)
1943                        mm->env_start = addr;
1944                else if (opt == PR_SET_MM_ENV_END)
1945                        mm->env_end = addr;
1946                break;
1947
1948        /*
1949         * This doesn't move auxiliary vector itself
1950         * since it's pinned to mm_struct, but allow
1951         * to fill vector with new values. It's up
1952         * to a caller to provide sane values here
1953         * otherwise user space tools which use this
1954         * vector might be unhappy.
1955         */
1956        case PR_SET_MM_AUXV: {
1957                unsigned long user_auxv[AT_VECTOR_SIZE];
1958
1959                if (arg4 > sizeof(user_auxv))
1960                        goto out;
1961                up_read(&mm->mmap_sem);
1962
1963                if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1964                        return -EFAULT;
1965
1966                /* Make sure the last entry is always AT_NULL */
1967                user_auxv[AT_VECTOR_SIZE - 2] = 0;
1968                user_auxv[AT_VECTOR_SIZE - 1] = 0;
1969
1970                BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1971
1972                task_lock(current);
1973                memcpy(mm->saved_auxv, user_auxv, arg4);
1974                task_unlock(current);
1975
1976                return 0;
1977        }
1978        default:
1979                goto out;
1980        }
1981
1982        error = 0;
1983out:
1984        up_read(&mm->mmap_sem);
1985        return error;
1986}
1987
1988static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1989{
1990        return put_user(me->clear_child_tid, tid_addr);
1991}
1992
1993#else /* CONFIG_CHECKPOINT_RESTORE */
1994static int prctl_set_mm(int opt, unsigned long addr,
1995                        unsigned long arg4, unsigned long arg5)
1996{
1997        return -EINVAL;
1998}
1999static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
2000{
2001        return -EINVAL;
2002}
2003#endif
2004
2005SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2006                unsigned long, arg4, unsigned long, arg5)
2007{
2008        struct task_struct *me = current;
2009        unsigned char comm[sizeof(me->comm)];
2010        long error;
2011
2012        error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2013        if (error != -ENOSYS)
2014                return error;
2015
2016        error = 0;
2017        switch (option) {
2018        case PR_SET_PDEATHSIG:
2019                if (!valid_signal(arg2)) {
2020                        error = -EINVAL;
2021                        break;
2022                }
2023                me->pdeath_signal = arg2;
2024                break;
2025        case PR_GET_PDEATHSIG:
2026                error = put_user(me->pdeath_signal, (int __user *)arg2);
2027                break;
2028        case PR_GET_DUMPABLE:
2029                error = get_dumpable(me->mm);
2030                break;
2031        case PR_SET_DUMPABLE:
2032                if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
2033                        error = -EINVAL;
2034                        break;
2035                }
2036                set_dumpable(me->mm, arg2);
2037                break;
2038
2039        case PR_SET_UNALIGN:
2040                error = SET_UNALIGN_CTL(me, arg2);
2041                break;
2042        case PR_GET_UNALIGN:
2043                error = GET_UNALIGN_CTL(me, arg2);
2044                break;
2045        case PR_SET_FPEMU:
2046                error = SET_FPEMU_CTL(me, arg2);
2047                break;
2048        case PR_GET_FPEMU:
2049                error = GET_FPEMU_CTL(me, arg2);
2050                break;
2051        case PR_SET_FPEXC:
2052                error = SET_FPEXC_CTL(me, arg2);
2053                break;
2054        case PR_GET_FPEXC:
2055                error = GET_FPEXC_CTL(me, arg2);
2056                break;
2057        case PR_GET_TIMING:
2058                error = PR_TIMING_STATISTICAL;
2059                break;
2060        case PR_SET_TIMING:
2061                if (arg2 != PR_TIMING_STATISTICAL)
2062                        error = -EINVAL;
2063                break;
2064        case PR_SET_NAME:
2065                comm[sizeof(me->comm) - 1] = 0;
2066                if (strncpy_from_user(comm, (char __user *)arg2,
2067                                      sizeof(me->comm) - 1) < 0)
2068                        return -EFAULT;
2069                set_task_comm(me, comm);
2070                proc_comm_connector(me);
2071                break;
2072        case PR_GET_NAME:
2073                get_task_comm(comm, me);
2074                if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
2075                        return -EFAULT;
2076                break;
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        case PR_GET_SECCOMP:
2084                error = prctl_get_seccomp();
2085                break;
2086        case PR_SET_SECCOMP:
2087                error = prctl_set_seccomp(arg2, (char __user *)arg3);
2088                break;
2089        case PR_GET_TSC:
2090                error = GET_TSC_CTL(arg2);
2091                break;
2092        case PR_SET_TSC:
2093                error = SET_TSC_CTL(arg2);
2094                break;
2095        case PR_TASK_PERF_EVENTS_DISABLE:
2096                error = perf_event_task_disable();
2097                break;
2098        case PR_TASK_PERF_EVENTS_ENABLE:
2099                error = perf_event_task_enable();
2100                break;
2101        case PR_GET_TIMERSLACK:
2102                error = current->timer_slack_ns;
2103                break;
2104        case PR_SET_TIMERSLACK:
2105                if (arg2 <= 0)
2106                        current->timer_slack_ns =
2107                                        current->default_timer_slack_ns;
2108                else
2109                        current->timer_slack_ns = arg2;
2110                break;
2111        case PR_MCE_KILL:
2112                if (arg4 | arg5)
2113                        return -EINVAL;
2114                switch (arg2) {
2115                case PR_MCE_KILL_CLEAR:
2116                        if (arg3 != 0)
2117                                return -EINVAL;
2118                        current->flags &= ~PF_MCE_PROCESS;
2119                        break;
2120                case PR_MCE_KILL_SET:
2121                        current->flags |= PF_MCE_PROCESS;
2122                        if (arg3 == PR_MCE_KILL_EARLY)
2123                                current->flags |= PF_MCE_EARLY;
2124                        else if (arg3 == PR_MCE_KILL_LATE)
2125                                current->flags &= ~PF_MCE_EARLY;
2126                        else if (arg3 == PR_MCE_KILL_DEFAULT)
2127                                current->flags &=
2128                                                ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2129                        else
2130                                return -EINVAL;
2131                        break;
2132                default:
2133                        return -EINVAL;
2134                }
2135                break;
2136        case PR_MCE_KILL_GET:
2137                if (arg2 | arg3 | arg4 | arg5)
2138                        return -EINVAL;
2139                if (current->flags & PF_MCE_PROCESS)
2140                        error = (current->flags & PF_MCE_EARLY) ?
2141                                PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2142                else
2143                        error = PR_MCE_KILL_DEFAULT;
2144                break;
2145        case PR_SET_MM:
2146                error = prctl_set_mm(arg2, arg3, arg4, arg5);
2147                break;
2148        case PR_GET_TID_ADDRESS:
2149                error = prctl_get_tid_address(me, (int __user **)arg2);
2150                break;
2151        case PR_SET_CHILD_SUBREAPER:
2152                me->signal->is_child_subreaper = !!arg2;
2153                break;
2154        case PR_GET_CHILD_SUBREAPER:
2155                error = put_user(me->signal->is_child_subreaper,
2156                                 (int __user *)arg2);
2157                break;
2158        case PR_SET_NO_NEW_PRIVS:
2159                if (arg2 != 1 || arg3 || arg4 || arg5)
2160                        return -EINVAL;
2161
2162                current->no_new_privs = 1;
2163                break;
2164        case PR_GET_NO_NEW_PRIVS:
2165                if (arg2 || arg3 || arg4 || arg5)
2166                        return -EINVAL;
2167                return current->no_new_privs ? 1 : 0;
2168        default:
2169                error = -EINVAL;
2170                break;
2171        }
2172        return error;
2173}
2174
2175SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2176                struct getcpu_cache __user *, unused)
2177{
2178        int err = 0;
2179        int cpu = raw_smp_processor_id();
2180        if (cpup)
2181                err |= put_user(cpu, cpup);
2182        if (nodep)
2183                err |= put_user(cpu_to_node(cpu), nodep);
2184        return err ? -EFAULT : 0;
2185}
2186
2187char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2188
2189static int __orderly_poweroff(bool force)
2190{
2191        char **argv;
2192        static char *envp[] = {
2193                "HOME=/",
2194                "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2195                NULL
2196        };
2197        int ret;
2198
2199        argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
2200        if (argv) {
2201                ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
2202                argv_free(argv);
2203        } else {
2204                printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2205                                         __func__, poweroff_cmd);
2206                ret = -ENOMEM;
2207        }
2208
2209        if (ret && force) {
2210                printk(KERN_WARNING "Failed to start orderly shutdown: "
2211                                        "forcing the issue\n");
2212                /*
2213                 * I guess this should try to kick off some daemon to sync and
2214                 * poweroff asap.  Or not even bother syncing if we're doing an
2215                 * emergency shutdown?
2216                 */
2217                emergency_sync();
2218                kernel_power_off();
2219        }
2220
2221        return ret;
2222}
2223
2224static bool poweroff_force;
2225
2226static void poweroff_work_func(struct work_struct *work)
2227{
2228        __orderly_poweroff(poweroff_force);
2229}
2230
2231static DECLARE_WORK(poweroff_work, poweroff_work_func);
2232
2233/**
2234 * orderly_poweroff - Trigger an orderly system poweroff
2235 * @force: force poweroff if command execution fails
2236 *
2237 * This may be called from any context to trigger a system shutdown.
2238 * If the orderly shutdown fails, it will force an immediate shutdown.
2239 */
2240int orderly_poweroff(bool force)
2241{
2242        if (force) /* do not override the pending "true" */
2243                poweroff_force = true;
2244        schedule_work(&poweroff_work);
2245        return 0;
2246}
2247EXPORT_SYMBOL_GPL(orderly_poweroff);
2248
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