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/notifier.h>
  12 #include <linux/reboot.h>
  13 #include <linux/prctl.h>
  14 #include <linux/highuid.h>
  15 #include <linux/fs.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/gfp.h>
  40
  41 #include <linux/compat.h>
  42 #include <linux/syscalls.h>
  43 #include <linux/kprobes.h>
  44 #include <linux/user_namespace.h>
  45
  46 #include <asm/uaccess.h>
  47 #include <asm/io.h>
  48 #include <asm/unistd.h>
  49
  50 #ifndef SET_UNALIGN_CTL
  51 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  52 #endif
  53 #ifndef GET_UNALIGN_CTL
  54 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  55 #endif
  56 #ifndef SET_FPEMU_CTL
  57 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  58 #endif
  59 #ifndef GET_FPEMU_CTL
  60 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  61 #endif
  62 #ifndef SET_FPEXC_CTL
  63 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  64 #endif
  65 #ifndef GET_FPEXC_CTL
  66 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  67 #endif
  68 #ifndef GET_ENDIAN
  69 # define GET_ENDIAN(a,b)        (-EINVAL)
  70 #endif
  71 #ifndef SET_ENDIAN
  72 # define SET_ENDIAN(a,b)        (-EINVAL)
  73 #endif
  74 #ifndef GET_TSC_CTL
  75 # define GET_TSC_CTL(a)         (-EINVAL)
  76 #endif
  77 #ifndef SET_TSC_CTL
  78 # define SET_TSC_CTL(a)         (-EINVAL)
  79 #endif
  80
  81 /*
  82  * this is where the system-wide overflow UID and GID are defined, for
  83  * architectures that now have 32-bit UID/GID but didn't in the past
  84  */
  85
  86 int overflowuid = DEFAULT_OVERFLOWUID;
  87 int overflowgid = DEFAULT_OVERFLOWGID;
  88
  89 #ifdef CONFIG_UID16
  90 EXPORT_SYMBOL(overflowuid);
  91 EXPORT_SYMBOL(overflowgid);
  92 #endif
  93
  94 /*
  95  * the same as above, but for filesystems which can only store a 16-bit
  96  * UID and GID. as such, this is needed on all architectures
  97  */
  98
  99 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 100 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 101
 102 EXPORT_SYMBOL(fs_overflowuid);
 103 EXPORT_SYMBOL(fs_overflowgid);
 104
 105 /*
 106  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 107  */
 108
 109 int C_A_D = 1;
 110 struct pid *cad_pid;
 111 EXPORT_SYMBOL(cad_pid);
 112
 113 /*
 114  * If set, this is used for preparing the system to power off.
 115  */
 116
 117 void (*pm_power_off_prepare)(void);
 118
 119 /*
 120  * set the priority of a task
 121  * - the caller must hold the RCU read lock
 122  */
 123 static int set_one_prio(struct task_struct *p, int niceval, int error)
 124 {
 125         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 126         int no_nice;
 127
 128         if (pcred->uid  != cred->euid &&
 129             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
 130                 error = -EPERM;
 131                 goto out;
 132         }
 133         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 134                 error = -EACCES;
 135                 goto out;
 136         }
 137         no_nice = security_task_setnice(p, niceval);
 138         if (no_nice) {
 139                 error = no_nice;
 140                 goto out;
 141         }
 142         if (error == -ESRCH)
 143                 error = 0;
 144         set_user_nice(p, niceval);
 145 out:
 146         return error;
 147 }
 148
 149 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 150 {
 151         struct task_struct *g, *p;
 152         struct user_struct *user;
 153         const struct cred *cred = current_cred();
 154         int error = -EINVAL;
 155         struct pid *pgrp;
 156
 157         if (which > PRIO_USER || which < PRIO_PROCESS)
 158                 goto out;
 159
 160         /* normalize: avoid signed division (rounding problems) */
 161         error = -ESRCH;
 162         if (niceval < -20)
 163                 niceval = -20;
 164         if (niceval > 19)
 165                 niceval = 19;
 166
 167         rcu_read_lock();
 168         read_lock(&tasklist_lock);
 169         switch (which) {
 170                 case PRIO_PROCESS:
 171                         if (who)
 172                                 p = find_task_by_vpid(who);
 173                         else
 174                                 p = current;
 175                         if (p)
 176                                 error = set_one_prio(p, niceval, error);
 177                         break;
 178                 case PRIO_PGRP:
 179                         if (who)
 180                                 pgrp = find_vpid(who);
 181                         else
 182                                 pgrp = task_pgrp(current);
 183                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 184                                 error = set_one_prio(p, niceval, error);
 185                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 186                         break;
 187                 case PRIO_USER:
 188                         user = (struct user_struct *) cred->user;
 189                         if (!who)
 190                                 who = cred->uid;
 191                         else if ((who != cred->uid) &&
 192                                  !(user = find_user(who)))
 193                                 goto out_unlock;        /* No processes for this user */
 194
 195                         do_each_thread(g, p) {
 196                                 if (__task_cred(p)->uid == who)
 197                                         error = set_one_prio(p, niceval, error);
 198                         } while_each_thread(g, p);
 199                         if (who != cred->uid)
 200                                 free_uid(user);         /* For find_user() */
 201                         break;
 202         }
 203 out_unlock:
 204         read_unlock(&tasklist_lock);
 205         rcu_read_unlock();
 206 out:
 207         return error;
 208 }
 209
 210 /*
 211  * Ugh. To avoid negative return values, "getpriority()" will
 212  * not return the normal nice-value, but a negated value that
 213  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 214  * to stay compatible.
 215  */
 216 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 217 {
 218         struct task_struct *g, *p;
 219         struct user_struct *user;
 220         const struct cred *cred = current_cred();
 221         long niceval, retval = -ESRCH;
 222         struct pid *pgrp;
 223
 224         if (which > PRIO_USER || which < PRIO_PROCESS)
 225                 return -EINVAL;
 226
 227         rcu_read_lock();
 228         read_lock(&tasklist_lock);
 229         switch (which) {
 230                 case PRIO_PROCESS:
 231                         if (who)
 232                                 p = find_task_by_vpid(who);
 233                         else
 234                                 p = current;
 235                         if (p) {
 236                                 niceval = 20 - task_nice(p);
 237                                 if (niceval > retval)
 238                                         retval = niceval;
 239                         }
 240                         break;
 241                 case PRIO_PGRP:
 242                         if (who)
 243                                 pgrp = find_vpid(who);
 244                         else
 245                                 pgrp = task_pgrp(current);
 246                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 247                                 niceval = 20 - task_nice(p);
 248                                 if (niceval > retval)
 249                                         retval = niceval;
 250                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 251                         break;
 252                 case PRIO_USER:
 253                         user = (struct user_struct *) cred->user;
 254                         if (!who)
 255                                 who = cred->uid;
 256                         else if ((who != cred->uid) &&
 257                                  !(user = find_user(who)))
 258                                 goto out_unlock;        /* No processes for this user */
 259
 260                         do_each_thread(g, p) {
 261                                 if (__task_cred(p)->uid == who) {
 262                                         niceval = 20 - task_nice(p);
 263                                         if (niceval > retval)
 264                                                 retval = niceval;
 265                                 }
 266                         } while_each_thread(g, p);
 267                         if (who != cred->uid)
 268                                 free_uid(user);         /* for find_user() */
 269                         break;
 270         }
 271 out_unlock:
 272         read_unlock(&tasklist_lock);
 273         rcu_read_unlock();
 274
 275         return retval;
 276 }
 277
 278 /**
 279  *      emergency_restart - reboot the system
 280  *
 281  *      Without shutting down any hardware or taking any locks
 282  *      reboot the system.  This is called when we know we are in
 283  *      trouble so this is our best effort to reboot.  This is
 284  *      safe to call in interrupt context.
 285  */
 286 void emergency_restart(void)
 287 {
 288         machine_emergency_restart();
 289 }
 290 EXPORT_SYMBOL_GPL(emergency_restart);
 291
 292 void kernel_restart_prepare(char *cmd)
 293 {
 294         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 295         system_state = SYSTEM_RESTART;
 296         device_shutdown();
 297         sysdev_shutdown();
 298 }
 299
 300 /**
 301  *      kernel_restart - reboot the system
 302  *      @cmd: pointer to buffer containing command to execute for restart
 303  *              or %NULL
 304  *
 305  *      Shutdown everything and perform a clean reboot.
 306  *      This is not safe to call in interrupt context.
 307  */
 308 void kernel_restart(char *cmd)
 309 {
 310         kernel_restart_prepare(cmd);
 311         if (!cmd)
 312                 printk(KERN_EMERG "Restarting system.\n");
 313         else
 314                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 315         machine_restart(cmd);
 316 }
 317 EXPORT_SYMBOL_GPL(kernel_restart);
 318
 319 static void kernel_shutdown_prepare(enum system_states state)
 320 {
 321         blocking_notifier_call_chain(&reboot_notifier_list,
 322                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 323         system_state = state;
 324         device_shutdown();
 325 }
 326 /**
 327  *      kernel_halt - halt the system
 328  *
 329  *      Shutdown everything and perform a clean system halt.
 330  */
 331 void kernel_halt(void)
 332 {
 333         kernel_shutdown_prepare(SYSTEM_HALT);
 334         sysdev_shutdown();
 335         printk(KERN_EMERG "System halted.\n");
 336         machine_halt();
 337 }
 338
 339 EXPORT_SYMBOL_GPL(kernel_halt);
 340
 341 /**
 342  *      kernel_power_off - power_off the system
 343  *
 344  *      Shutdown everything and perform a clean system power_off.
 345  */
 346 void kernel_power_off(void)
 347 {
 348         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 349         if (pm_power_off_prepare)
 350                 pm_power_off_prepare();
 351         disable_nonboot_cpus();
 352         sysdev_shutdown();
 353         printk(KERN_EMERG "Power down.\n");
 354         machine_power_off();
 355 }
 356 EXPORT_SYMBOL_GPL(kernel_power_off);
 357
 358 static DEFINE_MUTEX(reboot_mutex);
 359
 360 /*
 361  * Reboot system call: for obvious reasons only root may call it,
 362  * and even root needs to set up some magic numbers in the registers
 363  * so that some mistake won't make this reboot the whole machine.
 364  * You can also set the meaning of the ctrl-alt-del-key here.
 365  *
 366  * reboot doesn't sync: do that yourself before calling this.
 367  */
 368 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 369                 void __user *, arg)
 370 {
 371         char buffer[256];
 372         int ret = 0;
 373
 374         /* We only trust the superuser with rebooting the system. */
 375         if (!capable(CAP_SYS_BOOT))
 376                 return -EPERM;
 377
 378         /* For safety, we require "magic" arguments. */
 379         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 380             (magic2 != LINUX_REBOOT_MAGIC2 &&
 381                         magic2 != LINUX_REBOOT_MAGIC2A &&
 382                         magic2 != LINUX_REBOOT_MAGIC2B &&
 383                         magic2 != LINUX_REBOOT_MAGIC2C))
 384                 return -EINVAL;
 385
 386         /* Instead of trying to make the power_off code look like
 387          * halt when pm_power_off is not set do it the easy way.
 388          */
 389         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 390                 cmd = LINUX_REBOOT_CMD_HALT;
 391
 392         mutex_lock(&reboot_mutex);
 393         switch (cmd) {
 394         case LINUX_REBOOT_CMD_RESTART:
 395                 kernel_restart(NULL);
 396                 break;
 397
 398         case LINUX_REBOOT_CMD_CAD_ON:
 399                 C_A_D = 1;
 400                 break;
 401
 402         case LINUX_REBOOT_CMD_CAD_OFF:
 403                 C_A_D = 0;
 404                 break;
 405
 406         case LINUX_REBOOT_CMD_HALT:
 407                 kernel_halt();
 408                 do_exit(0);
 409                 panic("cannot halt");
 410
 411         case LINUX_REBOOT_CMD_POWER_OFF:
 412                 kernel_power_off();
 413                 do_exit(0);
 414                 break;
 415
 416         case LINUX_REBOOT_CMD_RESTART2:
 417                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 418                         ret = -EFAULT;
 419                         break;
 420                 }
 421                 buffer[sizeof(buffer) - 1] = '\0';
 422
 423                 kernel_restart(buffer);
 424                 break;
 425
 426 #ifdef CONFIG_KEXEC
 427         case LINUX_REBOOT_CMD_KEXEC:
 428                 ret = kernel_kexec();
 429                 break;
 430 #endif
 431
 432 #ifdef CONFIG_HIBERNATION
 433         case LINUX_REBOOT_CMD_SW_SUSPEND:
 434                 ret = hibernate();
 435                 break;
 436 #endif
 437
 438         default:
 439                 ret = -EINVAL;
 440                 break;
 441         }
 442         mutex_unlock(&reboot_mutex);
 443         return ret;
 444 }
 445
 446 static void deferred_cad(struct work_struct *dummy)
 447 {
 448         kernel_restart(NULL);
 449 }
 450
 451 /*
 452  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 453  * As it's called within an interrupt, it may NOT sync: the only choice
 454  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 455  */
 456 void ctrl_alt_del(void)
 457 {
 458         static DECLARE_WORK(cad_work, deferred_cad);
 459
 460         if (C_A_D)
 461                 schedule_work(&cad_work);
 462         else
 463                 kill_cad_pid(SIGINT, 1);
 464 }
 465
 466 /*
 467  * Unprivileged users may change the real gid to the effective gid
 468  * or vice versa.  (BSD-style)
 469  *
 470  * If you set the real gid at all, or set the effective gid to a value not
 471  * equal to the real gid, then the saved gid is set to the new effective gid.
 472  *
 473  * This makes it possible for a setgid program to completely drop its
 474  * privileges, which is often a useful assertion to make when you are doing
 475  * a security audit over a program.
 476  *
 477  * The general idea is that a program which uses just setregid() will be
 478  * 100% compatible with BSD.  A program which uses just setgid() will be
 479  * 100% compatible with POSIX with saved IDs.
 480  *
 481  * SMP: There are not races, the GIDs are checked only by filesystem
 482  *      operations (as far as semantic preservation is concerned).
 483  */
 484 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 485 {
 486         const struct cred *old;
 487         struct cred *new;
 488         int retval;
 489
 490         new = prepare_creds();
 491         if (!new)
 492                 return -ENOMEM;
 493         old = current_cred();
 494
 495         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 496         if (retval)
 497                 goto error;
 498
 499         retval = -EPERM;
 500         if (rgid != (gid_t) -1) {
 501                 if (old->gid == rgid ||
 502                     old->egid == rgid ||
 503                     capable(CAP_SETGID))
 504                         new->gid = rgid;
 505                 else
 506                         goto error;
 507         }
 508         if (egid != (gid_t) -1) {
 509                 if (old->gid == egid ||
 510                     old->egid == egid ||
 511                     old->sgid == egid ||
 512                     capable(CAP_SETGID))
 513                         new->egid = egid;
 514                 else
 515                         goto error;
 516         }
 517
 518         if (rgid != (gid_t) -1 ||
 519             (egid != (gid_t) -1 && egid != old->gid))
 520                 new->sgid = new->egid;
 521         new->fsgid = new->egid;
 522
 523         return commit_creds(new);
 524
 525 error:
 526         abort_creds(new);
 527         return retval;
 528 }
 529
 530 /*
 531  * setgid() is implemented like SysV w/ SAVED_IDS
 532  *
 533  * SMP: Same implicit races as above.
 534  */
 535 SYSCALL_DEFINE1(setgid, gid_t, gid)
 536 {
 537         const struct cred *old;
 538         struct cred *new;
 539         int retval;
 540
 541         new = prepare_creds();
 542         if (!new)
 543                 return -ENOMEM;
 544         old = current_cred();
 545
 546         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 547         if (retval)
 548                 goto error;
 549
 550         retval = -EPERM;
 551         if (capable(CAP_SETGID))
 552                 new->gid = new->egid = new->sgid = new->fsgid = gid;
 553         else if (gid == old->gid || gid == old->sgid)
 554                 new->egid = new->fsgid = gid;
 555         else
 556                 goto error;
 557
 558         return commit_creds(new);
 559
 560 error:
 561         abort_creds(new);
 562         return retval;
 563 }
 564
 565 /*
 566  * change the user struct in a credentials set to match the new UID
 567  */
 568 static int set_user(struct cred *new)
 569 {
 570         struct user_struct *new_user;
 571
 572         new_user = alloc_uid(current_user_ns(), new->uid);
 573         if (!new_user)
 574                 return -EAGAIN;
 575
 576         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 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         cputime_t tgutime, tgstime, cutime, cstime;
 915
 916         spin_lock_irq(&current->sighand->siglock);
 917         thread_group_times(current, &tgutime, &tgstime);
 918         cutime = current->signal->cutime;
 919         cstime = current->signal->cstime;
 920         spin_unlock_irq(&current->sighand->siglock);
 921         tms->tms_utime = cputime_to_clock_t(tgutime);
 922         tms->tms_stime = cputime_to_clock_t(tgstime);
 923         tms->tms_cutime = cputime_to_clock_t(cutime);
 924         tms->tms_cstime = cputime_to_clock_t(cstime);
 925 }
 926
 927 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 928 {
 929         if (tbuf) {
 930                 struct tms tmp;
 931
 932                 do_sys_times(&tmp);
 933                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 934                         return -EFAULT;
 935         }
 936         force_successful_syscall_return();
 937         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 938 }
 939
 940 /*
 941  * This needs some heavy checking ...
 942  * I just haven't the stomach for it. I also don't fully
 943  * understand sessions/pgrp etc. Let somebody who does explain it.
 944  *
 945  * OK, I think I have the protection semantics right.... this is really
 946  * only important on a multi-user system anyway, to make sure one user
 947  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 948  *
 949  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 950  * LBT 04.03.94
 951  */
 952 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 953 {
 954         struct task_struct *p;
 955         struct task_struct *group_leader = current->group_leader;
 956         struct pid *pgrp;
 957         int err;
 958
 959         if (!pid)
 960                 pid = task_pid_vnr(group_leader);
 961         if (!pgid)
 962                 pgid = pid;
 963         if (pgid < 0)
 964                 return -EINVAL;
 965         rcu_read_lock();
 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         rcu_read_unlock();
1020         return err;
1021 }
1022
1023 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1024 {
1025         struct task_struct *p;
1026         struct pid *grp;
1027         int retval;
1028
1029         rcu_read_lock();
1030         if (!pid)
1031                 grp = task_pgrp(current);
1032         else {
1033                 retval = -ESRCH;
1034                 p = find_task_by_vpid(pid);
1035                 if (!p)
1036                         goto out;
1037                 grp = task_pgrp(p);
1038                 if (!grp)
1039                         goto out;
1040
1041                 retval = security_task_getpgid(p);
1042                 if (retval)
1043                         goto out;
1044         }
1045         retval = pid_vnr(grp);
1046 out:
1047         rcu_read_unlock();
1048         return retval;
1049 }
1050
1051 #ifdef __ARCH_WANT_SYS_GETPGRP
1052
1053 SYSCALL_DEFINE0(getpgrp)
1054 {
1055         return sys_getpgid(0);
1056 }
1057
1058 #endif
1059
1060 SYSCALL_DEFINE1(getsid, pid_t, pid)
1061 {
1062         struct task_struct *p;
1063         struct pid *sid;
1064         int retval;
1065
1066         rcu_read_lock();
1067         if (!pid)
1068                 sid = task_session(current);
1069         else {
1070                 retval = -ESRCH;
1071                 p = find_task_by_vpid(pid);
1072                 if (!p)
1073                         goto out;
1074                 sid = task_session(p);
1075                 if (!sid)
1076                         goto out;
1077
1078                 retval = security_task_getsid(p);
1079                 if (retval)
1080                         goto out;
1081         }
1082         retval = pid_vnr(sid);
1083 out:
1084         rcu_read_unlock();
1085         return retval;
1086 }
1087
1088 SYSCALL_DEFINE0(setsid)
1089 {
1090         struct task_struct *group_leader = current->group_leader;
1091         struct pid *sid = task_pid(group_leader);
1092         pid_t session = pid_vnr(sid);
1093         int err = -EPERM;
1094
1095         write_lock_irq(&tasklist_lock);
1096         /* Fail if I am already a session leader */
1097         if (group_leader->signal->leader)
1098                 goto out;
1099
1100         /* Fail if a process group id already exists that equals the
1101          * proposed session id.
1102          */
1103         if (pid_task(sid, PIDTYPE_PGID))
1104                 goto out;
1105
1106         group_leader->signal->leader = 1;
1107         __set_special_pids(sid);
1108
1109         proc_clear_tty(group_leader);
1110
1111         err = session;
1112 out:
1113         write_unlock_irq(&tasklist_lock);
1114         if (err > 0)
1115                 proc_sid_connector(group_leader);
1116         return err;
1117 }
1118
1119 DECLARE_RWSEM(uts_sem);
1120
1121 #ifdef COMPAT_UTS_MACHINE
1122 #define override_architecture(name) \
1123         (personality(current->personality) == PER_LINUX32 && \
1124          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1125                       sizeof(COMPAT_UTS_MACHINE)))
1126 #else
1127 #define override_architecture(name)     0
1128 #endif
1129
1130 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1131 {
1132         int errno = 0;
1133
1134         down_read(&uts_sem);
1135         if (copy_to_user(name, utsname(), sizeof *name))
1136                 errno = -EFAULT;
1137         up_read(&uts_sem);
1138
1139         if (!errno && override_architecture(name))
1140                 errno = -EFAULT;
1141         return errno;
1142 }
1143
1144 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1145 /*
1146  * Old cruft
1147  */
1148 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1149 {
1150         int error = 0;
1151
1152         if (!name)
1153                 return -EFAULT;
1154
1155         down_read(&uts_sem);
1156         if (copy_to_user(name, utsname(), sizeof(*name)))
1157                 error = -EFAULT;
1158         up_read(&uts_sem);
1159
1160         if (!error && override_architecture(name))
1161                 error = -EFAULT;
1162         return error;
1163 }
1164
1165 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1166 {
1167         int error;
1168
1169         if (!name)
1170                 return -EFAULT;
1171         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1172                 return -EFAULT;
1173
1174         down_read(&uts_sem);
1175         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1176                                __OLD_UTS_LEN);
1177         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1178         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1179                                 __OLD_UTS_LEN);
1180         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1181         error |= __copy_to_user(&name->release, &utsname()->release,
1182                                 __OLD_UTS_LEN);
1183         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1184         error |= __copy_to_user(&name->version, &utsname()->version,
1185                                 __OLD_UTS_LEN);
1186         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1187         error |= __copy_to_user(&name->machine, &utsname()->machine,
1188                                 __OLD_UTS_LEN);
1189         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1190         up_read(&uts_sem);
1191
1192         if (!error && override_architecture(name))
1193                 error = -EFAULT;
1194         return error ? -EFAULT : 0;
1195 }
1196 #endif
1197
1198 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1199 {
1200         int errno;
1201         char tmp[__NEW_UTS_LEN];
1202
1203         if (!capable(CAP_SYS_ADMIN))
1204                 return -EPERM;
1205         if (len < 0 || len > __NEW_UTS_LEN)
1206                 return -EINVAL;
1207         down_write(&uts_sem);
1208         errno = -EFAULT;
1209         if (!copy_from_user(tmp, name, len)) {
1210                 struct new_utsname *u = utsname();
1211
1212                 memcpy(u->nodename, tmp, len);
1213                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1214                 errno = 0;
1215         }
1216         up_write(&uts_sem);
1217         return errno;
1218 }
1219
1220 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1221
1222 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1223 {
1224         int i, errno;
1225         struct new_utsname *u;
1226
1227         if (len < 0)
1228                 return -EINVAL;
1229         down_read(&uts_sem);
1230         u = utsname();
1231         i = 1 + strlen(u->nodename);
1232         if (i > len)
1233                 i = len;
1234         errno = 0;
1235         if (copy_to_user(name, u->nodename, i))
1236                 errno = -EFAULT;
1237         up_read(&uts_sem);
1238         return errno;
1239 }
1240
1241 #endif
1242
1243 /*
1244  * Only setdomainname; getdomainname can be implemented by calling
1245  * uname()
1246  */
1247 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1248 {
1249         int errno;
1250         char tmp[__NEW_UTS_LEN];
1251
1252         if (!capable(CAP_SYS_ADMIN))
1253                 return -EPERM;
1254         if (len < 0 || len > __NEW_UTS_LEN)
1255                 return -EINVAL;
1256
1257         down_write(&uts_sem);
1258         errno = -EFAULT;
1259         if (!copy_from_user(tmp, name, len)) {
1260                 struct new_utsname *u = utsname();
1261
1262                 memcpy(u->domainname, tmp, len);
1263                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1264                 errno = 0;
1265         }
1266         up_write(&uts_sem);
1267         return errno;
1268 }
1269
1270 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1271 {
1272         if (resource >= RLIM_NLIMITS)
1273                 return -EINVAL;
1274         else {
1275                 struct rlimit value;
1276                 task_lock(current->group_leader);
1277                 value = current->signal->rlim[resource];
1278                 task_unlock(current->group_leader);
1279                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1280         }
1281 }
1282
1283 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1284
1285 /*
1286  *      Back compatibility for getrlimit. Needed for some apps.
1287  */
1288
1289 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1290                 struct rlimit __user *, rlim)
1291 {
1292         struct rlimit x;
1293         if (resource >= RLIM_NLIMITS)
1294                 return -EINVAL;
1295
1296         task_lock(current->group_leader);
1297         x = current->signal->rlim[resource];
1298         task_unlock(current->group_leader);
1299         if (x.rlim_cur > 0x7FFFFFFF)
1300                 x.rlim_cur = 0x7FFFFFFF;
1301         if (x.rlim_max > 0x7FFFFFFF)
1302                 x.rlim_max = 0x7FFFFFFF;
1303         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1304 }
1305
1306 #endif
1307
1308 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1309 {
1310         struct rlimit new_rlim, *old_rlim;
1311         int retval;
1312
1313         if (resource >= RLIM_NLIMITS)
1314                 return -EINVAL;
1315         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1316                 return -EFAULT;
1317         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1318                 return -EINVAL;
1319         old_rlim = current->signal->rlim + resource;
1320         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1321             !capable(CAP_SYS_RESOURCE))
1322                 return -EPERM;
1323         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1324                 return -EPERM;
1325
1326         retval = security_task_setrlimit(resource, &new_rlim);
1327         if (retval)
1328                 return retval;
1329
1330         if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1331                 /*
1332                  * The caller is asking for an immediate RLIMIT_CPU
1333                  * expiry.  But we use the zero value to mean "it was
1334                  * never set".  So let's cheat and make it one second
1335                  * instead
1336                  */
1337                 new_rlim.rlim_cur = 1;
1338         }
1339
1340         task_lock(current->group_leader);
1341         *old_rlim = new_rlim;
1342         task_unlock(current->group_leader);
1343
1344         if (resource != RLIMIT_CPU)
1345                 goto out;
1346
1347         /*
1348          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1349          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1350          * very long-standing error, and fixing it now risks breakage of
1351          * applications, so we live with it
1352          */
1353         if (new_rlim.rlim_cur == RLIM_INFINITY)
1354                 goto out;
1355
1356         update_rlimit_cpu(new_rlim.rlim_cur);
1357 out:
1358         return 0;
1359 }
1360
1361 /*
1362  * It would make sense to put struct rusage in the task_struct,
1363  * except that would make the task_struct be *really big*.  After
1364  * task_struct gets moved into malloc'ed memory, it would
1365  * make sense to do this.  It will make moving the rest of the information
1366  * a lot simpler!  (Which we're not doing right now because we're not
1367  * measuring them yet).
1368  *
1369  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1370  * races with threads incrementing their own counters.  But since word
1371  * reads are atomic, we either get new values or old values and we don't
1372  * care which for the sums.  We always take the siglock to protect reading
1373  * the c* fields from p->signal from races with exit.c updating those
1374  * fields when reaping, so a sample either gets all the additions of a
1375  * given child after it's reaped, or none so this sample is before reaping.
1376  *
1377  * Locking:
1378  * We need to take the siglock for CHILDEREN, SELF and BOTH
1379  * for  the cases current multithreaded, non-current single threaded
1380  * non-current multithreaded.  Thread traversal is now safe with
1381  * the siglock held.
1382  * Strictly speaking, we donot need to take the siglock if we are current and
1383  * single threaded,  as no one else can take our signal_struct away, no one
1384  * else can  reap the  children to update signal->c* counters, and no one else
1385  * can race with the signal-> fields. If we do not take any lock, the
1386  * signal-> fields could be read out of order while another thread was just
1387  * exiting. So we should  place a read memory barrier when we avoid the lock.
1388  * On the writer side,  write memory barrier is implied in  __exit_signal
1389  * as __exit_signal releases  the siglock spinlock after updating the signal->
1390  * fields. But we don't do this yet to keep things simple.
1391  *
1392  */
1393
1394 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1395 {
1396         r->ru_nvcsw += t->nvcsw;
1397         r->ru_nivcsw += t->nivcsw;
1398         r->ru_minflt += t->min_flt;
1399         r->ru_majflt += t->maj_flt;
1400         r->ru_inblock += task_io_get_inblock(t);
1401         r->ru_oublock += task_io_get_oublock(t);
1402 }
1403
1404 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1405 {
1406         struct task_struct *t;
1407         unsigned long flags;
1408         cputime_t tgutime, tgstime, utime, stime;
1409         unsigned long maxrss = 0;
1410
1411         memset((char *) r, 0, sizeof *r);
1412         utime = stime = cputime_zero;
1413
1414         if (who == RUSAGE_THREAD) {
1415                 task_times(current, &utime, &stime);
1416                 accumulate_thread_rusage(p, r);
1417                 maxrss = p->signal->maxrss;
1418                 goto out;
1419         }
1420
1421         if (!lock_task_sighand(p, &flags))
1422                 return;
1423
1424         switch (who) {
1425                 case RUSAGE_BOTH:
1426                 case RUSAGE_CHILDREN:
1427                         utime = p->signal->cutime;
1428                         stime = p->signal->cstime;
1429                         r->ru_nvcsw = p->signal->cnvcsw;
1430                         r->ru_nivcsw = p->signal->cnivcsw;
1431                         r->ru_minflt = p->signal->cmin_flt;
1432                         r->ru_majflt = p->signal->cmaj_flt;
1433                         r->ru_inblock = p->signal->cinblock;
1434                         r->ru_oublock = p->signal->coublock;
1435                         maxrss = p->signal->cmaxrss;
1436
1437                         if (who == RUSAGE_CHILDREN)
1438                                 break;
1439
1440                 case RUSAGE_SELF:
1441                         thread_group_times(p, &tgutime, &tgstime);
1442                         utime = cputime_add(utime, tgutime);
1443                         stime = cputime_add(stime, tgstime);
1444                         r->ru_nvcsw += p->signal->nvcsw;
1445                         r->ru_nivcsw += p->signal->nivcsw;
1446                         r->ru_minflt += p->signal->min_flt;
1447                         r->ru_majflt += p->signal->maj_flt;
1448                         r->ru_inblock += p->signal->inblock;
1449                         r->ru_oublock += p->signal->oublock;
1450                         if (maxrss < p->signal->maxrss)
1451                                 maxrss = p->signal->maxrss;
1452                         t = p;
1453                         do {
1454                                 accumulate_thread_rusage(t, r);
1455                                 t = next_thread(t);
1456                         } while (t != p);
1457                         break;
1458
1459                 default:
1460                         BUG();
1461         }
1462         unlock_task_sighand(p, &flags);
1463
1464 out:
1465         cputime_to_timeval(utime, &r->ru_utime);
1466         cputime_to_timeval(stime, &r->ru_stime);
1467
1468         if (who != RUSAGE_CHILDREN) {
1469                 struct mm_struct *mm = get_task_mm(p);
1470                 if (mm) {
1471                         setmax_mm_hiwater_rss(&maxrss, mm);
1472                         mmput(mm);
1473                 }
1474         }
1475         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1476 }
1477
1478 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1479 {
1480         struct rusage r;
1481         k_getrusage(p, who, &r);
1482         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1483 }
1484
1485 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1486 {
1487         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1488             who != RUSAGE_THREAD)
1489                 return -EINVAL;
1490         return getrusage(current, who, ru);
1491 }
1492
1493 SYSCALL_DEFINE1(umask, int, mask)
1494 {
1495         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1496         return mask;
1497 }
1498
1499 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1500                 unsigned long, arg4, unsigned long, arg5)
1501 {
1502         struct task_struct *me = current;
1503         unsigned char comm[sizeof(me->comm)];
1504         long error;
1505
1506         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1507         if (error != -ENOSYS)
1508                 return error;
1509
1510         error = 0;
1511         switch (option) {
1512                 case PR_SET_PDEATHSIG:
1513                         if (!valid_signal(arg2)) {
1514                                 error = -EINVAL;
1515                                 break;
1516                         }
1517                         me->pdeath_signal = arg2;
1518                         error = 0;
1519                         break;
1520                 case PR_GET_PDEATHSIG:
1521                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1522                         break;
1523                 case PR_GET_DUMPABLE:
1524                         error = get_dumpable(me->mm);
1525                         break;
1526                 case PR_SET_DUMPABLE:
1527                         if (arg2 < 0 || arg2 > 1) {
1528                                 error = -EINVAL;
1529                                 break;
1530                         }
1531                         set_dumpable(me->mm, arg2);
1532                         error = 0;
1533                         break;
1534
1535                 case PR_SET_UNALIGN:
1536                         error = SET_UNALIGN_CTL(me, arg2);
1537                         break;
1538                 case PR_GET_UNALIGN:
1539                         error = GET_UNALIGN_CTL(me, arg2);
1540                         break;
1541                 case PR_SET_FPEMU:
1542                         error = SET_FPEMU_CTL(me, arg2);
1543                         break;
1544                 case PR_GET_FPEMU:
1545                         error = GET_FPEMU_CTL(me, arg2);
1546                         break;
1547                 case PR_SET_FPEXC:
1548                         error = SET_FPEXC_CTL(me, arg2);
1549                         break;
1550                 case PR_GET_FPEXC:
1551                         error = GET_FPEXC_CTL(me, arg2);
1552                         break;
1553                 case PR_GET_TIMING:
1554                         error = PR_TIMING_STATISTICAL;
1555                         break;
1556                 case PR_SET_TIMING:
1557                         if (arg2 != PR_TIMING_STATISTICAL)
1558                                 error = -EINVAL;
1559                         else
1560                                 error = 0;
1561                         break;
1562
1563                 case PR_SET_NAME:
1564                         comm[sizeof(me->comm)-1] = 0;
1565                         if (strncpy_from_user(comm, (char __user *)arg2,
1566                                               sizeof(me->comm) - 1) < 0)
1567                                 return -EFAULT;
1568                         set_task_comm(me, comm);
1569                         return 0;
1570                 case PR_GET_NAME:
1571                         get_task_comm(comm, me);
1572                         if (copy_to_user((char __user *)arg2, comm,
1573                                          sizeof(comm)))
1574                                 return -EFAULT;
1575                         return 0;
1576                 case PR_GET_ENDIAN:
1577                         error = GET_ENDIAN(me, arg2);
1578                         break;
1579                 case PR_SET_ENDIAN:
1580                         error = SET_ENDIAN(me, arg2);
1581                         break;
1582
1583                 case PR_GET_SECCOMP:
1584                         error = prctl_get_seccomp();
1585                         break;
1586                 case PR_SET_SECCOMP:
1587                         error = prctl_set_seccomp(arg2);
1588                         break;
1589                 case PR_GET_TSC:
1590                         error = GET_TSC_CTL(arg2);
1591                         break;
1592                 case PR_SET_TSC:
1593                         error = SET_TSC_CTL(arg2);
1594                         break;
1595                 case PR_TASK_PERF_EVENTS_DISABLE:
1596                         error = perf_event_task_disable();
1597                         break;
1598                 case PR_TASK_PERF_EVENTS_ENABLE:
1599                         error = perf_event_task_enable();
1600                         break;
1601                 case PR_GET_TIMERSLACK:
1602                         error = current->timer_slack_ns;
1603                         break;
1604                 case PR_SET_TIMERSLACK:
1605                         if (arg2 <= 0)
1606                                 current->timer_slack_ns =
1607                                         current->default_timer_slack_ns;
1608                         else
1609                                 current->timer_slack_ns = arg2;
1610                         error = 0;
1611                         break;
1612                 case PR_MCE_KILL:
1613                         if (arg4 | arg5)
1614                                 return -EINVAL;
1615                         switch (arg2) {
1616                         case PR_MCE_KILL_CLEAR:
1617                                 if (arg3 != 0)
1618                                         return -EINVAL;
1619                                 current->flags &= ~PF_MCE_PROCESS;
1620                                 break;
1621                         case PR_MCE_KILL_SET:
1622                                 current->flags |= PF_MCE_PROCESS;
1623                                 if (arg3 == PR_MCE_KILL_EARLY)
1624                                         current->flags |= PF_MCE_EARLY;
1625                                 else if (arg3 == PR_MCE_KILL_LATE)
1626                                         current->flags &= ~PF_MCE_EARLY;
1627                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1628                                         current->flags &=
1629                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1630                                 else
1631                                         return -EINVAL;
1632                                 break;
1633                         default:
1634                                 return -EINVAL;
1635                         }
1636                         error = 0;
1637                         break;
1638                 case PR_MCE_KILL_GET:
1639                         if (arg2 | arg3 | arg4 | arg5)
1640                                 return -EINVAL;
1641                         if (current->flags & PF_MCE_PROCESS)
1642                                 error = (current->flags & PF_MCE_EARLY) ?
1643                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1644                         else
1645                                 error = PR_MCE_KILL_DEFAULT;
1646                         break;
1647                 default:
1648                         error = -EINVAL;
1649                         break;
1650         }
1651         return error;
1652 }
1653
1654 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1655                 struct getcpu_cache __user *, unused)
1656 {
1657         int err = 0;
1658         int cpu = raw_smp_processor_id();
1659         if (cpup)
1660                 err |= put_user(cpu, cpup);
1661         if (nodep)
1662                 err |= put_user(cpu_to_node(cpu), nodep);
1663         return err ? -EFAULT : 0;
1664 }
1665
1666 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1667
1668 static void argv_cleanup(char **argv, char **envp)
1669 {
1670         argv_free(argv);
1671 }
1672
1673 /**
1674  * orderly_poweroff - Trigger an orderly system poweroff
1675  * @force: force poweroff if command execution fails
1676  *
1677  * This may be called from any context to trigger a system shutdown.
1678  * If the orderly shutdown fails, it will force an immediate shutdown.
1679  */
1680 int orderly_poweroff(bool force)
1681 {
1682         int argc;
1683         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1684         static char *envp[] = {
1685                 "HOME=/",
1686                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1687                 NULL
1688         };
1689         int ret = -ENOMEM;
1690         struct subprocess_info *info;
1691
1692         if (argv == NULL) {
1693                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1694                        __func__, poweroff_cmd);
1695                 goto out;
1696         }
1697
1698         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1699         if (info == NULL) {
1700                 argv_free(argv);
1701                 goto out;
1702         }
1703
1704         call_usermodehelper_setcleanup(info, argv_cleanup);
1705
1706         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1707
1708   out:
1709         if (ret && force) {
1710                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1711                        "forcing the issue\n");
1712
1713                 /* I guess this should try to kick off some daemon to
1714                    sync and poweroff asap.  Or not even bother syncing
1715                    if we're doing an emergency shutdown? */
1716                 emergency_sync();
1717                 kernel_power_off();
1718         }
1719
1720         return ret;
1721 }
1722 EXPORT_SYMBOL_GPL(orderly_poweroff);