kernel/sys.c

   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/mm.h>
   9 #include <linux/utsname.h>
  10 #include <linux/mman.h>
  11 #include <linux/smp_lock.h>
  12 #include <linux/notifier.h>
  13 #include <linux/reboot.h>
  14 #include <linux/prctl.h>
  15 #include <linux/highuid.h>
  16 #include <linux/fs.h>
  17 #include <linux/perf_event.h>
  18 #include <linux/resource.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kexec.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/capability.h>
  23 #include <linux/device.h>
  24 #include <linux/key.h>
  25 #include <linux/times.h>
  26 #include <linux/posix-timers.h>
  27 #include <linux/security.h>
  28 #include <linux/dcookies.h>
  29 #include <linux/suspend.h>
  30 #include <linux/tty.h>
  31 #include <linux/signal.h>
  32 #include <linux/cn_proc.h>
  33 #include <linux/getcpu.h>
  34 #include <linux/task_io_accounting_ops.h>
  35 #include <linux/seccomp.h>
  36 #include <linux/cpu.h>
  37 #include <linux/ptrace.h>
  38 #include <linux/fs_struct.h>
  39
  40 #include <linux/compat.h>
  41 #include <linux/syscalls.h>
  42 #include <linux/kprobes.h>
  43 #include <linux/user_namespace.h>
  44
  45 #include <asm/uaccess.h>
  46 #include <asm/io.h>
  47 #include <asm/unistd.h>
  48
  49 #ifndef SET_UNALIGN_CTL
  50 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  51 #endif
  52 #ifndef GET_UNALIGN_CTL
  53 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  54 #endif
  55 #ifndef SET_FPEMU_CTL
  56 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  57 #endif
  58 #ifndef GET_FPEMU_CTL
  59 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  60 #endif
  61 #ifndef SET_FPEXC_CTL
  62 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  63 #endif
  64 #ifndef GET_FPEXC_CTL
  65 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  66 #endif
  67 #ifndef GET_ENDIAN
  68 # define GET_ENDIAN(a,b)        (-EINVAL)
  69 #endif
  70 #ifndef SET_ENDIAN
  71 # define SET_ENDIAN(a,b)        (-EINVAL)
  72 #endif
  73 #ifndef GET_TSC_CTL
  74 # define GET_TSC_CTL(a)         (-EINVAL)
  75 #endif
  76 #ifndef SET_TSC_CTL
  77 # define SET_TSC_CTL(a)         (-EINVAL)
  78 #endif
  79
  80 /*
  81  * this is where the system-wide overflow UID and GID are defined, for
  82  * architectures that now have 32-bit UID/GID but didn't in the past
  83  */
  84
  85 int overflowuid = DEFAULT_OVERFLOWUID;
  86 int overflowgid = DEFAULT_OVERFLOWGID;
  87
  88 #ifdef CONFIG_UID16
  89 EXPORT_SYMBOL(overflowuid);
  90 EXPORT_SYMBOL(overflowgid);
  91 #endif
  92
  93 /*
  94  * the same as above, but for filesystems which can only store a 16-bit
  95  * UID and GID. as such, this is needed on all architectures
  96  */
  97
  98 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  99 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 100
 101 EXPORT_SYMBOL(fs_overflowuid);
 102 EXPORT_SYMBOL(fs_overflowgid);
 103
 104 /*
 105  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 106  */
 107
 108 int C_A_D = 1;
 109 struct pid *cad_pid;
 110 EXPORT_SYMBOL(cad_pid);
 111
 112 /*
 113  * If set, this is used for preparing the system to power off.
 114  */
 115
 116 void (*pm_power_off_prepare)(void);
 117
 118 /*
 119  * set the priority of a task
 120  * - the caller must hold the RCU read lock
 121  */
 122 static int set_one_prio(struct task_struct *p, int niceval, int error)
 123 {
 124         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 125         int no_nice;
 126
 127         if (pcred->uid  != cred->euid &&
 128             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
 129                 error = -EPERM;
 130                 goto out;
 131         }
 132         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 133                 error = -EACCES;
 134                 goto out;
 135         }
 136         no_nice = security_task_setnice(p, niceval);
 137         if (no_nice) {
 138                 error = no_nice;
 139                 goto out;
 140         }
 141         if (error == -ESRCH)
 142                 error = 0;
 143         set_user_nice(p, niceval);
 144 out:
 145         return error;
 146 }
 147
 148 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 149 {
 150         struct task_struct *g, *p;
 151         struct user_struct *user;
 152         const struct cred *cred = current_cred();
 153         int error = -EINVAL;
 154         struct pid *pgrp;
 155
 156         if (which > PRIO_USER || which < PRIO_PROCESS)
 157                 goto out;
 158
 159         /* normalize: avoid signed division (rounding problems) */
 160         error = -ESRCH;
 161         if (niceval < -20)
 162                 niceval = -20;
 163         if (niceval > 19)
 164                 niceval = 19;
 165
 166         read_lock(&tasklist_lock);
 167         switch (which) {
 168                 case PRIO_PROCESS:
 169                         if (who)
 170                                 p = find_task_by_vpid(who);
 171                         else
 172                                 p = current;
 173                         if (p)
 174                                 error = set_one_prio(p, niceval, error);
 175                         break;
 176                 case PRIO_PGRP:
 177                         if (who)
 178                                 pgrp = find_vpid(who);
 179                         else
 180                                 pgrp = task_pgrp(current);
 181                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 182                                 error = set_one_prio(p, niceval, error);
 183                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 184                         break;
 185                 case PRIO_USER:
 186                         user = (struct user_struct *) cred->user;
 187                         if (!who)
 188                                 who = cred->uid;
 189                         else if ((who != cred->uid) &&
 190                                  !(user = find_user(who)))
 191                                 goto out_unlock;        /* No processes for this user */
 192
 193                         do_each_thread(g, p)
 194                                 if (__task_cred(p)->uid == who)
 195                                         error = set_one_prio(p, niceval, error);
 196                         while_each_thread(g, p);
 197                         if (who != cred->uid)
 198                                 free_uid(user);         /* For find_user() */
 199                         break;
 200         }
 201 out_unlock:
 202         read_unlock(&tasklist_lock);
 203 out:
 204         return error;
 205 }
 206
 207 /*
 208  * Ugh. To avoid negative return values, "getpriority()" will
 209  * not return the normal nice-value, but a negated value that
 210  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 211  * to stay compatible.
 212  */
 213 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 214 {
 215         struct task_struct *g, *p;
 216         struct user_struct *user;
 217         const struct cred *cred = current_cred();
 218         long niceval, retval = -ESRCH;
 219         struct pid *pgrp;
 220
 221         if (which > PRIO_USER || which < PRIO_PROCESS)
 222                 return -EINVAL;
 223
 224         read_lock(&tasklist_lock);
 225         switch (which) {
 226                 case PRIO_PROCESS:
 227                         if (who)
 228                                 p = find_task_by_vpid(who);
 229                         else
 230                                 p = current;
 231                         if (p) {
 232                                 niceval = 20 - task_nice(p);
 233                                 if (niceval > retval)
 234                                         retval = niceval;
 235                         }
 236                         break;
 237                 case PRIO_PGRP:
 238                         if (who)
 239                                 pgrp = find_vpid(who);
 240                         else
 241                                 pgrp = task_pgrp(current);
 242                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 243                                 niceval = 20 - task_nice(p);
 244                                 if (niceval > retval)
 245                                         retval = niceval;
 246                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 247                         break;
 248                 case PRIO_USER:
 249                         user = (struct user_struct *) cred->user;
 250                         if (!who)
 251                                 who = cred->uid;
 252                         else if ((who != cred->uid) &&
 253                                  !(user = find_user(who)))
 254                                 goto out_unlock;        /* No processes for this user */
 255
 256                         do_each_thread(g, p)
 257                                 if (__task_cred(p)->uid == who) {
 258                                         niceval = 20 - task_nice(p);
 259                                         if (niceval > retval)
 260                                                 retval = niceval;
 261                                 }
 262                         while_each_thread(g, p);
 263                         if (who != cred->uid)
 264                                 free_uid(user);         /* for find_user() */
 265                         break;
 266         }
 267 out_unlock:
 268         read_unlock(&tasklist_lock);
 269
 270         return retval;
 271 }
 272
 273 /**
 274  *      emergency_restart - reboot the system
 275  *
 276  *      Without shutting down any hardware or taking any locks
 277  *      reboot the system.  This is called when we know we are in
 278  *      trouble so this is our best effort to reboot.  This is
 279  *      safe to call in interrupt context.
 280  */
 281 void emergency_restart(void)
 282 {
 283         machine_emergency_restart();
 284 }
 285 EXPORT_SYMBOL_GPL(emergency_restart);
 286
 287 void kernel_restart_prepare(char *cmd)
 288 {
 289         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 290         system_state = SYSTEM_RESTART;
 291         device_shutdown();
 292         sysdev_shutdown();
 293 }
 294
 295 /**
 296  *      kernel_restart - reboot the system
 297  *      @cmd: pointer to buffer containing command to execute for restart
 298  *              or %NULL
 299  *
 300  *      Shutdown everything and perform a clean reboot.
 301  *      This is not safe to call in interrupt context.
 302  */
 303 void kernel_restart(char *cmd)
 304 {
 305         kernel_restart_prepare(cmd);
 306         if (!cmd)
 307                 printk(KERN_EMERG "Restarting system.\n");
 308         else
 309                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 310         machine_restart(cmd);
 311 }
 312 EXPORT_SYMBOL_GPL(kernel_restart);
 313
 314 static void kernel_shutdown_prepare(enum system_states state)
 315 {
 316         blocking_notifier_call_chain(&reboot_notifier_list,
 317                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 318         system_state = state;
 319         device_shutdown();
 320 }
 321 /**
 322  *      kernel_halt - halt the system
 323  *
 324  *      Shutdown everything and perform a clean system halt.
 325  */
 326 void kernel_halt(void)
 327 {
 328         kernel_shutdown_prepare(SYSTEM_HALT);
 329         sysdev_shutdown();
 330         printk(KERN_EMERG "System halted.\n");
 331         machine_halt();
 332 }
 333
 334 EXPORT_SYMBOL_GPL(kernel_halt);
 335
 336 /**
 337  *      kernel_power_off - power_off the system
 338  *
 339  *      Shutdown everything and perform a clean system power_off.
 340  */
 341 void kernel_power_off(void)
 342 {
 343         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 344         if (pm_power_off_prepare)
 345                 pm_power_off_prepare();
 346         disable_nonboot_cpus();
 347         sysdev_shutdown();
 348         printk(KERN_EMERG "Power down.\n");
 349         machine_power_off();
 350 }
 351 EXPORT_SYMBOL_GPL(kernel_power_off);
 352 /*
 353  * Reboot system call: for obvious reasons only root may call it,
 354  * and even root needs to set up some magic numbers in the registers
 355  * so that some mistake won't make this reboot the whole machine.
 356  * You can also set the meaning of the ctrl-alt-del-key here.
 357  *
 358  * reboot doesn't sync: do that yourself before calling this.
 359  */
 360 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 361                 void __user *, arg)
 362 {
 363         char buffer[256];
 364         int ret = 0;
 365
 366         /* We only trust the superuser with rebooting the system. */
 367         if (!capable(CAP_SYS_BOOT))
 368                 return -EPERM;
 369
 370         /* For safety, we require "magic" arguments. */
 371         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 372             (magic2 != LINUX_REBOOT_MAGIC2 &&
 373                         magic2 != LINUX_REBOOT_MAGIC2A &&
 374                         magic2 != LINUX_REBOOT_MAGIC2B &&
 375                         magic2 != LINUX_REBOOT_MAGIC2C))
 376                 return -EINVAL;
 377
 378         /* Instead of trying to make the power_off code look like
 379          * halt when pm_power_off is not set do it the easy way.
 380          */
 381         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 382                 cmd = LINUX_REBOOT_CMD_HALT;
 383
 384         lock_kernel();
 385         switch (cmd) {
 386         case LINUX_REBOOT_CMD_RESTART:
 387                 kernel_restart(NULL);
 388                 break;
 389
 390         case LINUX_REBOOT_CMD_CAD_ON:
 391                 C_A_D = 1;
 392                 break;
 393
 394         case LINUX_REBOOT_CMD_CAD_OFF:
 395                 C_A_D = 0;
 396                 break;
 397
 398         case LINUX_REBOOT_CMD_HALT:
 399                 kernel_halt();
 400                 unlock_kernel();
 401                 do_exit(0);
 402                 panic("cannot halt");
 403
 404         case LINUX_REBOOT_CMD_POWER_OFF:
 405                 kernel_power_off();
 406                 unlock_kernel();
 407                 do_exit(0);
 408                 break;
 409
 410         case LINUX_REBOOT_CMD_RESTART2:
 411                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 412                         unlock_kernel();
 413                         return -EFAULT;
 414                 }
 415                 buffer[sizeof(buffer) - 1] = '\0';
 416
 417                 kernel_restart(buffer);
 418                 break;
 419
 420 #ifdef CONFIG_KEXEC
 421         case LINUX_REBOOT_CMD_KEXEC:
 422                 ret = kernel_kexec();
 423                 break;
 424 #endif
 425
 426 #ifdef CONFIG_HIBERNATION
 427         case LINUX_REBOOT_CMD_SW_SUSPEND:
 428                 ret = hibernate();
 429                 break;
 430 #endif
 431
 432         default:
 433                 ret = -EINVAL;
 434                 break;
 435         }
 436         unlock_kernel();
 437         return ret;
 438 }
 439
 440 static void deferred_cad(struct work_struct *dummy)
 441 {
 442         kernel_restart(NULL);
 443 }
 444
 445 /*
 446  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 447  * As it's called within an interrupt, it may NOT sync: the only choice
 448  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 449  */
 450 void ctrl_alt_del(void)
 451 {
 452         static DECLARE_WORK(cad_work, deferred_cad);
 453
 454         if (C_A_D)
 455                 schedule_work(&cad_work);
 456         else
 457                 kill_cad_pid(SIGINT, 1);
 458 }
 459
 460 /*
 461  * Unprivileged users may change the real gid to the effective gid
 462  * or vice versa.  (BSD-style)
 463  *
 464  * If you set the real gid at all, or set the effective gid to a value not
 465  * equal to the real gid, then the saved gid is set to the new effective gid.
 466  *
 467  * This makes it possible for a setgid program to completely drop its
 468  * privileges, which is often a useful assertion to make when you are doing
 469  * a security audit over a program.
 470  *
 471  * The general idea is that a program which uses just setregid() will be
 472  * 100% compatible with BSD.  A program which uses just setgid() will be
 473  * 100% compatible with POSIX with saved IDs.
 474  *
 475  * SMP: There are not races, the GIDs are checked only by filesystem
 476  *      operations (as far as semantic preservation is concerned).
 477  */
 478 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 479 {
 480         const struct cred *old;
 481         struct cred *new;
 482         int retval;
 483
 484         new = prepare_creds();
 485         if (!new)
 486                 return -ENOMEM;
 487         old = current_cred();
 488
 489         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 490         if (retval)
 491                 goto error;
 492
 493         retval = -EPERM;
 494         if (rgid != (gid_t) -1) {
 495                 if (old->gid == rgid ||
 496                     old->egid == rgid ||
 497                     capable(CAP_SETGID))
 498                         new->gid = rgid;
 499                 else
 500                         goto error;
 501         }
 502         if (egid != (gid_t) -1) {
 503                 if (old->gid == egid ||
 504                     old->egid == egid ||
 505                     old->sgid == egid ||
 506                     capable(CAP_SETGID))
 507                         new->egid = egid;
 508                 else
 509                         goto error;
 510         }
 511
 512         if (rgid != (gid_t) -1 ||
 513             (egid != (gid_t) -1 && egid != old->gid))
 514                 new->sgid = new->egid;
 515         new->fsgid = new->egid;
 516
 517         return commit_creds(new);
 518
 519 error:
 520         abort_creds(new);
 521         return retval;
 522 }
 523
 524 /*
 525  * setgid() is implemented like SysV w/ SAVED_IDS
 526  *
 527  * SMP: Same implicit races as above.
 528  */
 529 SYSCALL_DEFINE1(setgid, gid_t, gid)
 530 {
 531         const struct cred *old;
 532         struct cred *new;
 533         int retval;
 534
 535         new = prepare_creds();
 536         if (!new)
 537                 return -ENOMEM;
 538         old = current_cred();
 539
 540         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 541         if (retval)
 542                 goto error;
 543
 544         retval = -EPERM;
 545         if (capable(CAP_SETGID))
 546                 new->gid = new->egid = new->sgid = new->fsgid = gid;
 547         else if (gid == old->gid || gid == old->sgid)
 548                 new->egid = new->fsgid = gid;
 549         else
 550                 goto error;
 551
 552         return commit_creds(new);
 553
 554 error:
 555         abort_creds(new);
 556         return retval;
 557 }
 558
 559 /*
 560  * change the user struct in a credentials set to match the new UID
 561  */
 562 static int set_user(struct cred *new)
 563 {
 564         struct user_struct *new_user;
 565
 566         new_user = alloc_uid(current_user_ns(), new->uid);
 567         if (!new_user)
 568                 return -EAGAIN;
 569
 570         if (!task_can_switch_user(new_user, current)) {
 571                 free_uid(new_user);
 572                 return -EINVAL;
 573         }
 574
 575         if (atomic_read(&new_user->processes) >=
 576                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 577                         new_user != INIT_USER) {
 578                 free_uid(new_user);
 579                 return -EAGAIN;
 580         }
 581
 582         free_uid(new->user);
 583         new->user = new_user;
 584         return 0;
 585 }
 586
 587 /*
 588  * Unprivileged users may change the real uid to the effective uid
 589  * or vice versa.  (BSD-style)
 590  *
 591  * If you set the real uid at all, or set the effective uid to a value not
 592  * equal to the real uid, then the saved uid is set to the new effective uid.
 593  *
 594  * This makes it possible for a setuid program to completely drop its
 595  * privileges, which is often a useful assertion to make when you are doing
 596  * a security audit over a program.
 597  *
 598  * The general idea is that a program which uses just setreuid() will be
 599  * 100% compatible with BSD.  A program which uses just setuid() will be
 600  * 100% compatible with POSIX with saved IDs.
 601  */
 602 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 603 {
 604         const struct cred *old;
 605         struct cred *new;
 606         int retval;
 607
 608         new = prepare_creds();
 609         if (!new)
 610                 return -ENOMEM;
 611         old = current_cred();
 612
 613         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 614         if (retval)
 615                 goto error;
 616
 617         retval = -EPERM;
 618         if (ruid != (uid_t) -1) {
 619                 new->uid = ruid;
 620                 if (old->uid != ruid &&
 621                     old->euid != ruid &&
 622                     !capable(CAP_SETUID))
 623                         goto error;
 624         }
 625
 626         if (euid != (uid_t) -1) {
 627                 new->euid = euid;
 628                 if (old->uid != euid &&
 629                     old->euid != euid &&
 630                     old->suid != euid &&
 631                     !capable(CAP_SETUID))
 632                         goto error;
 633         }
 634
 635         if (new->uid != old->uid) {
 636                 retval = set_user(new);
 637                 if (retval < 0)
 638                         goto error;
 639         }
 640         if (ruid != (uid_t) -1 ||
 641             (euid != (uid_t) -1 && euid != old->uid))
 642                 new->suid = new->euid;
 643         new->fsuid = new->euid;
 644
 645         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 646         if (retval < 0)
 647                 goto error;
 648
 649         return commit_creds(new);
 650
 651 error:
 652         abort_creds(new);
 653         return retval;
 654 }
 655
 656 /*
 657  * setuid() is implemented like SysV with SAVED_IDS
 658  *
 659  * Note that SAVED_ID's is deficient in that a setuid root program
 660  * like sendmail, for example, cannot set its uid to be a normal
 661  * user and then switch back, because if you're root, setuid() sets
 662  * the saved uid too.  If you don't like this, blame the bright people
 663  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 664  * will allow a root program to temporarily drop privileges and be able to
 665  * regain them by swapping the real and effective uid.
 666  */
 667 SYSCALL_DEFINE1(setuid, uid_t, uid)
 668 {
 669         const struct cred *old;
 670         struct cred *new;
 671         int retval;
 672
 673         new = prepare_creds();
 674         if (!new)
 675                 return -ENOMEM;
 676         old = current_cred();
 677
 678         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 679         if (retval)
 680                 goto error;
 681
 682         retval = -EPERM;
 683         if (capable(CAP_SETUID)) {
 684                 new->suid = new->uid = uid;
 685                 if (uid != old->uid) {
 686                         retval = set_user(new);
 687                         if (retval < 0)
 688                                 goto error;
 689                 }
 690         } else if (uid != old->uid && uid != new->suid) {
 691                 goto error;
 692         }
 693
 694         new->fsuid = new->euid = uid;
 695
 696         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 697         if (retval < 0)
 698                 goto error;
 699
 700         return commit_creds(new);
 701
 702 error:
 703         abort_creds(new);
 704         return retval;
 705 }
 706
 707
 708 /*
 709  * This function implements a generic ability to update ruid, euid,
 710  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 711  */
 712 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 713 {
 714         const struct cred *old;
 715         struct cred *new;
 716         int retval;
 717
 718         new = prepare_creds();
 719         if (!new)
 720                 return -ENOMEM;
 721
 722         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 723         if (retval)
 724                 goto error;
 725         old = current_cred();
 726
 727         retval = -EPERM;
 728         if (!capable(CAP_SETUID)) {
 729                 if (ruid != (uid_t) -1 && ruid != old->uid &&
 730                     ruid != old->euid  && ruid != old->suid)
 731                         goto error;
 732                 if (euid != (uid_t) -1 && euid != old->uid &&
 733                     euid != old->euid  && euid != old->suid)
 734                         goto error;
 735                 if (suid != (uid_t) -1 && suid != old->uid &&
 736                     suid != old->euid  && suid != old->suid)
 737                         goto error;
 738         }
 739
 740         if (ruid != (uid_t) -1) {
 741                 new->uid = ruid;
 742                 if (ruid != old->uid) {
 743                         retval = set_user(new);
 744                         if (retval < 0)
 745                                 goto error;
 746                 }
 747         }
 748         if (euid != (uid_t) -1)
 749                 new->euid = euid;
 750         if (suid != (uid_t) -1)
 751                 new->suid = suid;
 752         new->fsuid = new->euid;
 753
 754         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 755         if (retval < 0)
 756                 goto error;
 757
 758         return commit_creds(new);
 759
 760 error:
 761         abort_creds(new);
 762         return retval;
 763 }
 764
 765 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
 766 {
 767         const struct cred *cred = current_cred();
 768         int retval;
 769
 770         if (!(retval   = put_user(cred->uid,  ruid)) &&
 771             !(retval   = put_user(cred->euid, euid)))
 772                 retval = put_user(cred->suid, suid);
 773
 774         return retval;
 775 }
 776
 777 /*
 778  * Same as above, but for rgid, egid, sgid.
 779  */
 780 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 781 {
 782         const struct cred *old;
 783         struct cred *new;
 784         int retval;
 785
 786         new = prepare_creds();
 787         if (!new)
 788                 return -ENOMEM;
 789         old = current_cred();
 790
 791         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 792         if (retval)
 793                 goto error;
 794
 795         retval = -EPERM;
 796         if (!capable(CAP_SETGID)) {
 797                 if (rgid != (gid_t) -1 && rgid != old->gid &&
 798                     rgid != old->egid  && rgid != old->sgid)
 799                         goto error;
 800                 if (egid != (gid_t) -1 && egid != old->gid &&
 801                     egid != old->egid  && egid != old->sgid)
 802                         goto error;
 803                 if (sgid != (gid_t) -1 && sgid != old->gid &&
 804                     sgid != old->egid  && sgid != old->sgid)
 805                         goto error;
 806         }
 807
 808         if (rgid != (gid_t) -1)
 809                 new->gid = rgid;
 810         if (egid != (gid_t) -1)
 811                 new->egid = egid;
 812         if (sgid != (gid_t) -1)
 813                 new->sgid = sgid;
 814         new->fsgid = new->egid;
 815
 816         return commit_creds(new);
 817
 818 error:
 819         abort_creds(new);
 820         return retval;
 821 }
 822
 823 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
 824 {
 825         const struct cred *cred = current_cred();
 826         int retval;
 827
 828         if (!(retval   = put_user(cred->gid,  rgid)) &&
 829             !(retval   = put_user(cred->egid, egid)))
 830                 retval = put_user(cred->sgid, sgid);
 831
 832         return retval;
 833 }
 834
 835
 836 /*
 837  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 838  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 839  * whatever uid it wants to). It normally shadows "euid", except when
 840  * explicitly set by setfsuid() or for access..
 841  */
 842 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 843 {
 844         const struct cred *old;
 845         struct cred *new;
 846         uid_t old_fsuid;
 847
 848         new = prepare_creds();
 849         if (!new)
 850                 return current_fsuid();
 851         old = current_cred();
 852         old_fsuid = old->fsuid;
 853
 854         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS) < 0)
 855                 goto error;
 856
 857         if (uid == old->uid  || uid == old->euid  ||
 858             uid == old->suid || uid == old->fsuid ||
 859             capable(CAP_SETUID)) {
 860                 if (uid != old_fsuid) {
 861                         new->fsuid = uid;
 862                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 863                                 goto change_okay;
 864                 }
 865         }
 866
 867 error:
 868         abort_creds(new);
 869         return old_fsuid;
 870
 871 change_okay:
 872         commit_creds(new);
 873         return old_fsuid;
 874 }
 875
 876 /*
 877  * Samma på svenska..
 878  */
 879 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 880 {
 881         const struct cred *old;
 882         struct cred *new;
 883         gid_t old_fsgid;
 884
 885         new = prepare_creds();
 886         if (!new)
 887                 return current_fsgid();
 888         old = current_cred();
 889         old_fsgid = old->fsgid;
 890
 891         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 892                 goto error;
 893
 894         if (gid == old->gid  || gid == old->egid  ||
 895             gid == old->sgid || gid == old->fsgid ||
 896             capable(CAP_SETGID)) {
 897                 if (gid != old_fsgid) {
 898                         new->fsgid = gid;
 899                         goto change_okay;
 900                 }
 901         }
 902
 903 error:
 904         abort_creds(new);
 905         return old_fsgid;
 906
 907 change_okay:
 908         commit_creds(new);
 909         return old_fsgid;
 910 }
 911
 912 void do_sys_times(struct tms *tms)
 913 {
 914         struct task_cputime cputime;
 915         cputime_t cutime, cstime;
 916
 917         thread_group_cputime(current, &cputime);
 918         spin_lock_irq(&current->sighand->siglock);
 919         cutime = current->signal->cutime;
 920         cstime = current->signal->cstime;
 921         spin_unlock_irq(&current->sighand->siglock);
 922         tms->tms_utime = cputime_to_clock_t(cputime.utime);
 923         tms->tms_stime = cputime_to_clock_t(cputime.stime);
 924         tms->tms_cutime = cputime_to_clock_t(cutime);
 925         tms->tms_cstime = cputime_to_clock_t(cstime);
 926 }
 927
 928 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 929 {
 930         if (tbuf) {
 931                 struct tms tmp;
 932
 933                 do_sys_times(&tmp);
 934                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 935                         return -EFAULT;
 936         }
 937         force_successful_syscall_return();
 938         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 939 }
 940
 941 /*
 942  * This needs some heavy checking ...
 943  * I just haven't the stomach for it. I also don't fully
 944  * understand sessions/pgrp etc. Let somebody who does explain it.
 945  *
 946  * OK, I think I have the protection semantics right.... this is really
 947  * only important on a multi-user system anyway, to make sure one user
 948  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 949  *
 950  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 951  * LBT 04.03.94
 952  */
 953 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 954 {
 955         struct task_struct *p;
 956         struct task_struct *group_leader = current->group_leader;
 957         struct pid *pgrp;
 958         int err;
 959
 960         if (!pid)
 961                 pid = task_pid_vnr(group_leader);
 962         if (!pgid)
 963                 pgid = pid;
 964         if (pgid < 0)
 965                 return -EINVAL;
 966
 967         /* From this point forward we keep holding onto the tasklist lock
 968          * so that our parent does not change from under us. -DaveM
 969          */
 970         write_lock_irq(&tasklist_lock);
 971
 972         err = -ESRCH;
 973         p = find_task_by_vpid(pid);
 974         if (!p)
 975                 goto out;
 976
 977         err = -EINVAL;
 978         if (!thread_group_leader(p))
 979                 goto out;
 980
 981         if (same_thread_group(p->real_parent, group_leader)) {
 982                 err = -EPERM;
 983                 if (task_session(p) != task_session(group_leader))
 984                         goto out;
 985                 err = -EACCES;
 986                 if (p->did_exec)
 987                         goto out;
 988         } else {
 989                 err = -ESRCH;
 990                 if (p != group_leader)
 991                         goto out;
 992         }
 993
 994         err = -EPERM;
 995         if (p->signal->leader)
 996                 goto out;
 997
 998         pgrp = task_pid(p);
 999         if (pgid != pid) {
1000                 struct task_struct *g;
1001
1002                 pgrp = find_vpid(pgid);
1003                 g = pid_task(pgrp, PIDTYPE_PGID);
1004                 if (!g || task_session(g) != task_session(group_leader))
1005                         goto out;
1006         }
1007
1008         err = security_task_setpgid(p, pgid);
1009         if (err)
1010                 goto out;
1011
1012         if (task_pgrp(p) != pgrp)
1013                 change_pid(p, PIDTYPE_PGID, pgrp);
1014
1015         err = 0;
1016 out:
1017         /* All paths lead to here, thus we are safe. -DaveM */
1018         write_unlock_irq(&tasklist_lock);
1019         return err;
1020 }
1021
1022 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1023 {
1024         struct task_struct *p;
1025         struct pid *grp;
1026         int retval;
1027
1028         rcu_read_lock();
1029         if (!pid)
1030                 grp = task_pgrp(current);
1031         else {
1032                 retval = -ESRCH;
1033                 p = find_task_by_vpid(pid);
1034                 if (!p)
1035                         goto out;
1036                 grp = task_pgrp(p);
1037                 if (!grp)
1038                         goto out;
1039
1040                 retval = security_task_getpgid(p);
1041                 if (retval)
1042                         goto out;
1043         }
1044         retval = pid_vnr(grp);
1045 out:
1046         rcu_read_unlock();
1047         return retval;
1048 }
1049
1050 #ifdef __ARCH_WANT_SYS_GETPGRP
1051
1052 SYSCALL_DEFINE0(getpgrp)
1053 {
1054         return sys_getpgid(0);
1055 }
1056
1057 #endif
1058
1059 SYSCALL_DEFINE1(getsid, pid_t, pid)
1060 {
1061         struct task_struct *p;
1062         struct pid *sid;
1063         int retval;
1064
1065         rcu_read_lock();
1066         if (!pid)
1067                 sid = task_session(current);
1068         else {
1069                 retval = -ESRCH;
1070                 p = find_task_by_vpid(pid);
1071                 if (!p)
1072                         goto out;
1073                 sid = task_session(p);
1074                 if (!sid)
1075                         goto out;
1076
1077                 retval = security_task_getsid(p);
1078                 if (retval)
1079                         goto out;
1080         }
1081         retval = pid_vnr(sid);
1082 out:
1083         rcu_read_unlock();
1084         return retval;
1085 }
1086
1087 SYSCALL_DEFINE0(setsid)
1088 {
1089         struct task_struct *group_leader = current->group_leader;
1090         struct pid *sid = task_pid(group_leader);
1091         pid_t session = pid_vnr(sid);
1092         int err = -EPERM;
1093
1094         write_lock_irq(&tasklist_lock);
1095         /* Fail if I am already a session leader */
1096         if (group_leader->signal->leader)
1097                 goto out;
1098
1099         /* Fail if a process group id already exists that equals the
1100          * proposed session id.
1101          */
1102         if (pid_task(sid, PIDTYPE_PGID))
1103                 goto out;
1104
1105         group_leader->signal->leader = 1;
1106         __set_special_pids(sid);
1107
1108         proc_clear_tty(group_leader);
1109
1110         err = session;
1111 out:
1112         write_unlock_irq(&tasklist_lock);
1113         return err;
1114 }
1115
1116 DECLARE_RWSEM(uts_sem);
1117
1118 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1119 {
1120         int errno = 0;
1121
1122         down_read(&uts_sem);
1123         if (copy_to_user(name, utsname(), sizeof *name))
1124                 errno = -EFAULT;
1125         up_read(&uts_sem);
1126         return errno;
1127 }
1128
1129 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1130 {
1131         int errno;
1132         char tmp[__NEW_UTS_LEN];
1133
1134         if (!capable(CAP_SYS_ADMIN))
1135                 return -EPERM;
1136         if (len < 0 || len > __NEW_UTS_LEN)
1137                 return -EINVAL;
1138         down_write(&uts_sem);
1139         errno = -EFAULT;
1140         if (!copy_from_user(tmp, name, len)) {
1141                 struct new_utsname *u = utsname();
1142
1143                 memcpy(u->nodename, tmp, len);
1144                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1145                 errno = 0;
1146         }
1147         up_write(&uts_sem);
1148         return errno;
1149 }
1150
1151 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1152
1153 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1154 {
1155         int i, errno;
1156         struct new_utsname *u;
1157
1158         if (len < 0)
1159                 return -EINVAL;
1160         down_read(&uts_sem);
1161         u = utsname();
1162         i = 1 + strlen(u->nodename);
1163         if (i > len)
1164                 i = len;
1165         errno = 0;
1166         if (copy_to_user(name, u->nodename, i))
1167                 errno = -EFAULT;
1168         up_read(&uts_sem);
1169         return errno;
1170 }
1171
1172 #endif
1173
1174 /*
1175  * Only setdomainname; getdomainname can be implemented by calling
1176  * uname()
1177  */
1178 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1179 {
1180         int errno;
1181         char tmp[__NEW_UTS_LEN];
1182
1183         if (!capable(CAP_SYS_ADMIN))
1184                 return -EPERM;
1185         if (len < 0 || len > __NEW_UTS_LEN)
1186                 return -EINVAL;
1187
1188         down_write(&uts_sem);
1189         errno = -EFAULT;
1190         if (!copy_from_user(tmp, name, len)) {
1191                 struct new_utsname *u = utsname();
1192
1193                 memcpy(u->domainname, tmp, len);
1194                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1195                 errno = 0;
1196         }
1197         up_write(&uts_sem);
1198         return errno;
1199 }
1200
1201 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1202 {
1203         if (resource >= RLIM_NLIMITS)
1204                 return -EINVAL;
1205         else {
1206                 struct rlimit value;
1207                 task_lock(current->group_leader);
1208                 value = current->signal->rlim[resource];
1209                 task_unlock(current->group_leader);
1210                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1211         }
1212 }
1213
1214 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1215
1216 /*
1217  *      Back compatibility for getrlimit. Needed for some apps.
1218  */
1219
1220 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1221                 struct rlimit __user *, rlim)
1222 {
1223         struct rlimit x;
1224         if (resource >= RLIM_NLIMITS)
1225                 return -EINVAL;
1226
1227         task_lock(current->group_leader);
1228         x = current->signal->rlim[resource];
1229         task_unlock(current->group_leader);
1230         if (x.rlim_cur > 0x7FFFFFFF)
1231                 x.rlim_cur = 0x7FFFFFFF;
1232         if (x.rlim_max > 0x7FFFFFFF)
1233                 x.rlim_max = 0x7FFFFFFF;
1234         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1235 }
1236
1237 #endif
1238
1239 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1240 {
1241         struct rlimit new_rlim, *old_rlim;
1242         int retval;
1243
1244         if (resource >= RLIM_NLIMITS)
1245                 return -EINVAL;
1246         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1247                 return -EFAULT;
1248         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1249                 return -EINVAL;
1250         old_rlim = current->signal->rlim + resource;
1251         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1252             !capable(CAP_SYS_RESOURCE))
1253                 return -EPERM;
1254         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1255                 return -EPERM;
1256
1257         retval = security_task_setrlimit(resource, &new_rlim);
1258         if (retval)
1259                 return retval;
1260
1261         if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1262                 /*
1263                  * The caller is asking for an immediate RLIMIT_CPU
1264                  * expiry.  But we use the zero value to mean "it was
1265                  * never set".  So let's cheat and make it one second
1266                  * instead
1267                  */
1268                 new_rlim.rlim_cur = 1;
1269         }
1270
1271         task_lock(current->group_leader);
1272         *old_rlim = new_rlim;
1273         task_unlock(current->group_leader);
1274
1275         if (resource != RLIMIT_CPU)
1276                 goto out;
1277
1278         /*
1279          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1280          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1281          * very long-standing error, and fixing it now risks breakage of
1282          * applications, so we live with it
1283          */
1284         if (new_rlim.rlim_cur == RLIM_INFINITY)
1285                 goto out;
1286
1287         update_rlimit_cpu(new_rlim.rlim_cur);
1288 out:
1289         return 0;
1290 }
1291
1292 /*
1293  * It would make sense to put struct rusage in the task_struct,
1294  * except that would make the task_struct be *really big*.  After
1295  * task_struct gets moved into malloc'ed memory, it would
1296  * make sense to do this.  It will make moving the rest of the information
1297  * a lot simpler!  (Which we're not doing right now because we're not
1298  * measuring them yet).
1299  *
1300  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1301  * races with threads incrementing their own counters.  But since word
1302  * reads are atomic, we either get new values or old values and we don't
1303  * care which for the sums.  We always take the siglock to protect reading
1304  * the c* fields from p->signal from races with exit.c updating those
1305  * fields when reaping, so a sample either gets all the additions of a
1306  * given child after it's reaped, or none so this sample is before reaping.
1307  *
1308  * Locking:
1309  * We need to take the siglock for CHILDEREN, SELF and BOTH
1310  * for  the cases current multithreaded, non-current single threaded
1311  * non-current multithreaded.  Thread traversal is now safe with
1312  * the siglock held.
1313  * Strictly speaking, we donot need to take the siglock if we are current and
1314  * single threaded,  as no one else can take our signal_struct away, no one
1315  * else can  reap the  children to update signal->c* counters, and no one else
1316  * can race with the signal-> fields. If we do not take any lock, the
1317  * signal-> fields could be read out of order while another thread was just
1318  * exiting. So we should  place a read memory barrier when we avoid the lock.
1319  * On the writer side,  write memory barrier is implied in  __exit_signal
1320  * as __exit_signal releases  the siglock spinlock after updating the signal->
1321  * fields. But we don't do this yet to keep things simple.
1322  *
1323  */
1324
1325 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1326 {
1327         r->ru_nvcsw += t->nvcsw;
1328         r->ru_nivcsw += t->nivcsw;
1329         r->ru_minflt += t->min_flt;
1330         r->ru_majflt += t->maj_flt;
1331         r->ru_inblock += task_io_get_inblock(t);
1332         r->ru_oublock += task_io_get_oublock(t);
1333 }
1334
1335 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1336 {
1337         struct task_struct *t;
1338         unsigned long flags;
1339         cputime_t utime, stime;
1340         struct task_cputime cputime;
1341
1342         memset((char *) r, 0, sizeof *r);
1343         utime = stime = cputime_zero;
1344
1345         if (who == RUSAGE_THREAD) {
1346                 utime = task_utime(current);
1347                 stime = task_stime(current);
1348                 accumulate_thread_rusage(p, r);
1349                 goto out;
1350         }
1351
1352         if (!lock_task_sighand(p, &flags))
1353                 return;
1354
1355         switch (who) {
1356                 case RUSAGE_BOTH:
1357                 case RUSAGE_CHILDREN:
1358                         utime = p->signal->cutime;
1359                         stime = p->signal->cstime;
1360                         r->ru_nvcsw = p->signal->cnvcsw;
1361                         r->ru_nivcsw = p->signal->cnivcsw;
1362                         r->ru_minflt = p->signal->cmin_flt;
1363                         r->ru_majflt = p->signal->cmaj_flt;
1364                         r->ru_inblock = p->signal->cinblock;
1365                         r->ru_oublock = p->signal->coublock;
1366
1367                         if (who == RUSAGE_CHILDREN)
1368                                 break;
1369
1370                 case RUSAGE_SELF:
1371                         thread_group_cputime(p, &cputime);
1372                         utime = cputime_add(utime, cputime.utime);
1373                         stime = cputime_add(stime, cputime.stime);
1374                         r->ru_nvcsw += p->signal->nvcsw;
1375                         r->ru_nivcsw += p->signal->nivcsw;
1376                         r->ru_minflt += p->signal->min_flt;
1377                         r->ru_majflt += p->signal->maj_flt;
1378                         r->ru_inblock += p->signal->inblock;
1379                         r->ru_oublock += p->signal->oublock;
1380                         t = p;
1381                         do {
1382                                 accumulate_thread_rusage(t, r);
1383                                 t = next_thread(t);
1384                         } while (t != p);
1385                         break;
1386
1387                 default:
1388                         BUG();
1389         }
1390         unlock_task_sighand(p, &flags);
1391
1392 out:
1393         cputime_to_timeval(utime, &r->ru_utime);
1394         cputime_to_timeval(stime, &r->ru_stime);
1395 }
1396
1397 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1398 {
1399         struct rusage r;
1400         k_getrusage(p, who, &r);
1401         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1402 }
1403
1404 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1405 {
1406         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1407             who != RUSAGE_THREAD)
1408                 return -EINVAL;
1409         return getrusage(current, who, ru);
1410 }
1411
1412 SYSCALL_DEFINE1(umask, int, mask)
1413 {
1414         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1415         return mask;
1416 }
1417
1418 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1419                 unsigned long, arg4, unsigned long, arg5)
1420 {
1421         struct task_struct *me = current;
1422         unsigned char comm[sizeof(me->comm)];
1423         long error;
1424
1425         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1426         if (error != -ENOSYS)
1427                 return error;
1428
1429         error = 0;
1430         switch (option) {
1431                 case PR_SET_PDEATHSIG:
1432                         if (!valid_signal(arg2)) {
1433                                 error = -EINVAL;
1434                                 break;
1435                         }
1436                         me->pdeath_signal = arg2;
1437                         error = 0;
1438                         break;
1439                 case PR_GET_PDEATHSIG:
1440                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1441                         break;
1442                 case PR_GET_DUMPABLE:
1443                         error = get_dumpable(me->mm);
1444                         break;
1445                 case PR_SET_DUMPABLE:
1446                         if (arg2 < 0 || arg2 > 1) {
1447                                 error = -EINVAL;
1448                                 break;
1449                         }
1450                         set_dumpable(me->mm, arg2);
1451                         error = 0;
1452                         break;
1453
1454                 case PR_SET_UNALIGN:
1455                         error = SET_UNALIGN_CTL(me, arg2);
1456                         break;
1457                 case PR_GET_UNALIGN:
1458                         error = GET_UNALIGN_CTL(me, arg2);
1459                         break;
1460                 case PR_SET_FPEMU:
1461                         error = SET_FPEMU_CTL(me, arg2);
1462                         break;
1463                 case PR_GET_FPEMU:
1464                         error = GET_FPEMU_CTL(me, arg2);
1465                         break;
1466                 case PR_SET_FPEXC:
1467                         error = SET_FPEXC_CTL(me, arg2);
1468                         break;
1469                 case PR_GET_FPEXC:
1470                         error = GET_FPEXC_CTL(me, arg2);
1471                         break;
1472                 case PR_GET_TIMING:
1473                         error = PR_TIMING_STATISTICAL;
1474                         break;
1475                 case PR_SET_TIMING:
1476                         if (arg2 != PR_TIMING_STATISTICAL)
1477                                 error = -EINVAL;
1478                         else
1479                                 error = 0;
1480                         break;
1481
1482                 case PR_SET_NAME:
1483                         comm[sizeof(me->comm)-1] = 0;
1484                         if (strncpy_from_user(comm, (char __user *)arg2,
1485                                               sizeof(me->comm) - 1) < 0)
1486                                 return -EFAULT;
1487                         set_task_comm(me, comm);
1488                         return 0;
1489                 case PR_GET_NAME:
1490                         get_task_comm(comm, me);
1491                         if (copy_to_user((char __user *)arg2, comm,
1492                                          sizeof(comm)))
1493                                 return -EFAULT;
1494                         return 0;
1495                 case PR_GET_ENDIAN:
1496                         error = GET_ENDIAN(me, arg2);
1497                         break;
1498                 case PR_SET_ENDIAN:
1499                         error = SET_ENDIAN(me, arg2);
1500                         break;
1501
1502                 case PR_GET_SECCOMP:
1503                         error = prctl_get_seccomp();
1504                         break;
1505                 case PR_SET_SECCOMP:
1506                         error = prctl_set_seccomp(arg2);
1507                         break;
1508                 case PR_GET_TSC:
1509                         error = GET_TSC_CTL(arg2);
1510                         break;
1511                 case PR_SET_TSC:
1512                         error = SET_TSC_CTL(arg2);
1513                         break;
1514                 case PR_TASK_PERF_EVENTS_DISABLE:
1515                         error = perf_event_task_disable();
1516                         break;
1517                 case PR_TASK_PERF_EVENTS_ENABLE:
1518                         error = perf_event_task_enable();
1519                         break;
1520                 case PR_GET_TIMERSLACK:
1521                         error = current->timer_slack_ns;
1522                         break;
1523                 case PR_SET_TIMERSLACK:
1524                         if (arg2 <= 0)
1525                                 current->timer_slack_ns =
1526                                         current->default_timer_slack_ns;
1527                         else
1528                                 current->timer_slack_ns = arg2;
1529                         error = 0;
1530                         break;
1531                 default:
1532                         error = -EINVAL;
1533                         break;
1534         }
1535         return error;
1536 }
1537
1538 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1539                 struct getcpu_cache __user *, unused)
1540 {
1541         int err = 0;
1542         int cpu = raw_smp_processor_id();
1543         if (cpup)
1544                 err |= put_user(cpu, cpup);
1545         if (nodep)
1546                 err |= put_user(cpu_to_node(cpu), nodep);
1547         return err ? -EFAULT : 0;
1548 }
1549
1550 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1551
1552 static void argv_cleanup(char **argv, char **envp)
1553 {
1554         argv_free(argv);
1555 }
1556
1557 /**
1558  * orderly_poweroff - Trigger an orderly system poweroff
1559  * @force: force poweroff if command execution fails
1560  *
1561  * This may be called from any context to trigger a system shutdown.
1562  * If the orderly shutdown fails, it will force an immediate shutdown.
1563  */
1564 int orderly_poweroff(bool force)
1565 {
1566         int argc;
1567         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1568         static char *envp[] = {
1569                 "HOME=/",
1570                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1571                 NULL
1572         };
1573         int ret = -ENOMEM;
1574         struct subprocess_info *info;
1575
1576         if (argv == NULL) {
1577                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1578                        __func__, poweroff_cmd);
1579                 goto out;
1580         }
1581
1582         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1583         if (info == NULL) {
1584                 argv_free(argv);
1585                 goto out;
1586         }
1587
1588         call_usermodehelper_setcleanup(info, argv_cleanup);
1589
1590         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1591
1592   out:
1593         if (ret && force) {
1594                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1595                        "forcing the issue\n");
1596
1597                 /* I guess this should try to kick off some daemon to
1598                    sync and poweroff asap.  Or not even bother syncing
1599                    if we're doing an emergency shutdown? */
1600                 emergency_sync();
1601                 kernel_power_off();
1602         }
1603
1604         return ret;
1605 }
1606 EXPORT_SYMBOL_GPL(orderly_poweroff);