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/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/ptrace.h>
  37 #include <linux/fs_struct.h>
  38
  39 #include <linux/compat.h>
  40 #include <linux/syscalls.h>
  41 #include <linux/kprobes.h>
  42 #include <linux/user_namespace.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <asm/io.h>
  46 #include <asm/unistd.h>
  47
  48 #ifndef SET_UNALIGN_CTL
  49 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  50 #endif
  51 #ifndef GET_UNALIGN_CTL
  52 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  53 #endif
  54 #ifndef SET_FPEMU_CTL
  55 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  56 #endif
  57 #ifndef GET_FPEMU_CTL
  58 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  59 #endif
  60 #ifndef SET_FPEXC_CTL
  61 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  62 #endif
  63 #ifndef GET_FPEXC_CTL
  64 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  65 #endif
  66 #ifndef GET_ENDIAN
  67 # define GET_ENDIAN(a,b)        (-EINVAL)
  68 #endif
  69 #ifndef SET_ENDIAN
  70 # define SET_ENDIAN(a,b)        (-EINVAL)
  71 #endif
  72 #ifndef GET_TSC_CTL
  73 # define GET_TSC_CTL(a)         (-EINVAL)
  74 #endif
  75 #ifndef SET_TSC_CTL
  76 # define SET_TSC_CTL(a)         (-EINVAL)
  77 #endif
  78
  79 /*
  80  * this is where the system-wide overflow UID and GID are defined, for
  81  * architectures that now have 32-bit UID/GID but didn't in the past
  82  */
  83
  84 int overflowuid = DEFAULT_OVERFLOWUID;
  85 int overflowgid = DEFAULT_OVERFLOWGID;
  86
  87 #ifdef CONFIG_UID16
  88 EXPORT_SYMBOL(overflowuid);
  89 EXPORT_SYMBOL(overflowgid);
  90 #endif
  91
  92 /*
  93  * the same as above, but for filesystems which can only store a 16-bit
  94  * UID and GID. as such, this is needed on all architectures
  95  */
  96
  97 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  98 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  99
 100 EXPORT_SYMBOL(fs_overflowuid);
 101 EXPORT_SYMBOL(fs_overflowgid);
 102
 103 /*
 104  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 105  */
 106
 107 int C_A_D = 1;
 108 struct pid *cad_pid;
 109 EXPORT_SYMBOL(cad_pid);
 110
 111 /*
 112  * If set, this is used for preparing the system to power off.
 113  */
 114
 115 void (*pm_power_off_prepare)(void);
 116
 117 /*
 118  * set the priority of a task
 119  * - the caller must hold the RCU read lock
 120  */
 121 static int set_one_prio(struct task_struct *p, int niceval, int error)
 122 {
 123         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 124         int no_nice;
 125
 126         if (pcred->uid  != cred->euid &&
 127             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
 128                 error = -EPERM;
 129                 goto out;
 130         }
 131         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 132                 error = -EACCES;
 133                 goto out;
 134         }
 135         no_nice = security_task_setnice(p, niceval);
 136         if (no_nice) {
 137                 error = no_nice;
 138                 goto out;
 139         }
 140         if (error == -ESRCH)
 141                 error = 0;
 142         set_user_nice(p, niceval);
 143 out:
 144         return error;
 145 }
 146
 147 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 148 {
 149         struct task_struct *g, *p;
 150         struct user_struct *user;
 151         const struct cred *cred = current_cred();
 152         int error = -EINVAL;
 153         struct pid *pgrp;
 154
 155         if (which > PRIO_USER || which < PRIO_PROCESS)
 156                 goto out;
 157
 158         /* normalize: avoid signed division (rounding problems) */
 159         error = -ESRCH;
 160         if (niceval < -20)
 161                 niceval = -20;
 162         if (niceval > 19)
 163                 niceval = 19;
 164
 165         read_lock(&tasklist_lock);
 166         switch (which) {
 167                 case PRIO_PROCESS:
 168                         if (who)
 169                                 p = find_task_by_vpid(who);
 170                         else
 171                                 p = current;
 172                         if (p)
 173                                 error = set_one_prio(p, niceval, error);
 174                         break;
 175                 case PRIO_PGRP:
 176                         if (who)
 177                                 pgrp = find_vpid(who);
 178                         else
 179                                 pgrp = task_pgrp(current);
 180                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 181                                 error = set_one_prio(p, niceval, error);
 182                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 183                         break;
 184                 case PRIO_USER:
 185                         user = (struct user_struct *) cred->user;
 186                         if (!who)
 187                                 who = cred->uid;
 188                         else if ((who != cred->uid) &&
 189                                  !(user = find_user(who)))
 190                                 goto out_unlock;        /* No processes for this user */
 191
 192                         do_each_thread(g, p)
 193                                 if (__task_cred(p)->uid == who)
 194                                         error = set_one_prio(p, niceval, error);
 195                         while_each_thread(g, p);
 196                         if (who != cred->uid)
 197                                 free_uid(user);         /* For find_user() */
 198                         break;
 199         }
 200 out_unlock:
 201         read_unlock(&tasklist_lock);
 202 out:
 203         return error;
 204 }
 205
 206 /*
 207  * Ugh. To avoid negative return values, "getpriority()" will
 208  * not return the normal nice-value, but a negated value that
 209  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 210  * to stay compatible.
 211  */
 212 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 213 {
 214         struct task_struct *g, *p;
 215         struct user_struct *user;
 216         const struct cred *cred = current_cred();
 217         long niceval, retval = -ESRCH;
 218         struct pid *pgrp;
 219
 220         if (which > PRIO_USER || which < PRIO_PROCESS)
 221                 return -EINVAL;
 222
 223         read_lock(&tasklist_lock);
 224         switch (which) {
 225                 case PRIO_PROCESS:
 226                         if (who)
 227                                 p = find_task_by_vpid(who);
 228                         else
 229                                 p = current;
 230                         if (p) {
 231                                 niceval = 20 - task_nice(p);
 232                                 if (niceval > retval)
 233                                         retval = niceval;
 234                         }
 235                         break;
 236                 case PRIO_PGRP:
 237                         if (who)
 238                                 pgrp = find_vpid(who);
 239                         else
 240                                 pgrp = task_pgrp(current);
 241                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 242                                 niceval = 20 - task_nice(p);
 243                                 if (niceval > retval)
 244                                         retval = niceval;
 245                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 246                         break;
 247                 case PRIO_USER:
 248                         user = (struct user_struct *) cred->user;
 249                         if (!who)
 250                                 who = cred->uid;
 251                         else if ((who != cred->uid) &&
 252                                  !(user = find_user(who)))
 253                                 goto out_unlock;        /* No processes for this user */
 254
 255                         do_each_thread(g, p)
 256                                 if (__task_cred(p)->uid == who) {
 257                                         niceval = 20 - task_nice(p);
 258                                         if (niceval > retval)
 259                                                 retval = niceval;
 260                                 }
 261                         while_each_thread(g, p);
 262                         if (who != cred->uid)
 263                                 free_uid(user);         /* for find_user() */
 264                         break;
 265         }
 266 out_unlock:
 267         read_unlock(&tasklist_lock);
 268
 269         return retval;
 270 }
 271
 272 /**
 273  *      emergency_restart - reboot the system
 274  *
 275  *      Without shutting down any hardware or taking any locks
 276  *      reboot the system.  This is called when we know we are in
 277  *      trouble so this is our best effort to reboot.  This is
 278  *      safe to call in interrupt context.
 279  */
 280 void emergency_restart(void)
 281 {
 282         machine_emergency_restart();
 283 }
 284 EXPORT_SYMBOL_GPL(emergency_restart);
 285
 286 void kernel_restart_prepare(char *cmd)
 287 {
 288         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 289         system_state = SYSTEM_RESTART;
 290         device_shutdown();
 291         sysdev_shutdown();
 292 }
 293
 294 /**
 295  *      kernel_restart - reboot the system
 296  *      @cmd: pointer to buffer containing command to execute for restart
 297  *              or %NULL
 298  *
 299  *      Shutdown everything and perform a clean reboot.
 300  *      This is not safe to call in interrupt context.
 301  */
 302 void kernel_restart(char *cmd)
 303 {
 304         kernel_restart_prepare(cmd);
 305         if (!cmd)
 306                 printk(KERN_EMERG "Restarting system.\n");
 307         else
 308                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 309         machine_restart(cmd);
 310 }
 311 EXPORT_SYMBOL_GPL(kernel_restart);
 312
 313 static void kernel_shutdown_prepare(enum system_states state)
 314 {
 315         blocking_notifier_call_chain(&reboot_notifier_list,
 316                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 317         system_state = state;
 318         device_shutdown();
 319 }
 320 /**
 321  *      kernel_halt - halt the system
 322  *
 323  *      Shutdown everything and perform a clean system halt.
 324  */
 325 void kernel_halt(void)
 326 {
 327         kernel_shutdown_prepare(SYSTEM_HALT);
 328         sysdev_shutdown();
 329         printk(KERN_EMERG "System halted.\n");
 330         machine_halt();
 331 }
 332
 333 EXPORT_SYMBOL_GPL(kernel_halt);
 334
 335 /**
 336  *      kernel_power_off - power_off the system
 337  *
 338  *      Shutdown everything and perform a clean system power_off.
 339  */
 340 void kernel_power_off(void)
 341 {
 342         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 343         if (pm_power_off_prepare)
 344                 pm_power_off_prepare();
 345         disable_nonboot_cpus();
 346         sysdev_shutdown();
 347         printk(KERN_EMERG "Power down.\n");
 348         machine_power_off();
 349 }
 350 EXPORT_SYMBOL_GPL(kernel_power_off);
 351 /*
 352  * Reboot system call: for obvious reasons only root may call it,
 353  * and even root needs to set up some magic numbers in the registers
 354  * so that some mistake won't make this reboot the whole machine.
 355  * You can also set the meaning of the ctrl-alt-del-key here.
 356  *
 357  * reboot doesn't sync: do that yourself before calling this.
 358  */
 359 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 360                 void __user *, arg)
 361 {
 362         char buffer[256];
 363
 364         /* We only trust the superuser with rebooting the system. */
 365         if (!capable(CAP_SYS_BOOT))
 366                 return -EPERM;
 367
 368         /* For safety, we require "magic" arguments. */
 369         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 370             (magic2 != LINUX_REBOOT_MAGIC2 &&
 371                         magic2 != LINUX_REBOOT_MAGIC2A &&
 372                         magic2 != LINUX_REBOOT_MAGIC2B &&
 373                         magic2 != LINUX_REBOOT_MAGIC2C))
 374                 return -EINVAL;
 375
 376         /* Instead of trying to make the power_off code look like
 377          * halt when pm_power_off is not set do it the easy way.
 378          */
 379         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 380                 cmd = LINUX_REBOOT_CMD_HALT;
 381
 382         lock_kernel();
 383         switch (cmd) {
 384         case LINUX_REBOOT_CMD_RESTART:
 385                 kernel_restart(NULL);
 386                 break;
 387
 388         case LINUX_REBOOT_CMD_CAD_ON:
 389                 C_A_D = 1;
 390                 break;
 391
 392         case LINUX_REBOOT_CMD_CAD_OFF:
 393                 C_A_D = 0;
 394                 break;
 395
 396         case LINUX_REBOOT_CMD_HALT:
 397                 kernel_halt();
 398                 unlock_kernel();
 399                 do_exit(0);
 400                 break;
 401
 402         case LINUX_REBOOT_CMD_POWER_OFF:
 403                 kernel_power_off();
 404                 unlock_kernel();
 405                 do_exit(0);
 406                 break;
 407
 408         case LINUX_REBOOT_CMD_RESTART2:
 409                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 410                         unlock_kernel();
 411                         return -EFAULT;
 412                 }
 413                 buffer[sizeof(buffer) - 1] = '\0';
 414
 415                 kernel_restart(buffer);
 416                 break;
 417
 418 #ifdef CONFIG_KEXEC
 419         case LINUX_REBOOT_CMD_KEXEC:
 420                 {
 421                         int ret;
 422                         ret = kernel_kexec();
 423                         unlock_kernel();
 424                         return ret;
 425                 }
 426 #endif
 427
 428 #ifdef CONFIG_HIBERNATION
 429         case LINUX_REBOOT_CMD_SW_SUSPEND:
 430                 {
 431                         int ret = hibernate();
 432                         unlock_kernel();
 433                         return ret;
 434                 }
 435 #endif
 436
 437         default:
 438                 unlock_kernel();
 439                 return -EINVAL;
 440         }
 441         unlock_kernel();
 442         return 0;
 443 }
 444
 445 static void deferred_cad(struct work_struct *dummy)
 446 {
 447         kernel_restart(NULL);
 448 }
 449
 450 /*
 451  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 452  * As it's called within an interrupt, it may NOT sync: the only choice
 453  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 454  */
 455 void ctrl_alt_del(void)
 456 {
 457         static DECLARE_WORK(cad_work, deferred_cad);
 458
 459         if (C_A_D)
 460                 schedule_work(&cad_work);
 461         else
 462                 kill_cad_pid(SIGINT, 1);
 463 }
 464
 465 /*
 466  * Unprivileged users may change the real gid to the effective gid
 467  * or vice versa.  (BSD-style)
 468  *
 469  * If you set the real gid at all, or set the effective gid to a value not
 470  * equal to the real gid, then the saved gid is set to the new effective gid.
 471  *
 472  * This makes it possible for a setgid program to completely drop its
 473  * privileges, which is often a useful assertion to make when you are doing
 474  * a security audit over a program.
 475  *
 476  * The general idea is that a program which uses just setregid() will be
 477  * 100% compatible with BSD.  A program which uses just setgid() will be
 478  * 100% compatible with POSIX with saved IDs.
 479  *
 480  * SMP: There are not races, the GIDs are checked only by filesystem
 481  *      operations (as far as semantic preservation is concerned).
 482  */
 483 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 484 {
 485         const struct cred *old;
 486         struct cred *new;
 487         int retval;
 488
 489         new = prepare_creds();
 490         if (!new)
 491                 return -ENOMEM;
 492         old = current_cred();
 493
 494         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 495         if (retval)
 496                 goto error;
 497
 498         retval = -EPERM;
 499         if (rgid != (gid_t) -1) {
 500                 if (old->gid == rgid ||
 501                     old->egid == rgid ||
 502                     capable(CAP_SETGID))
 503                         new->gid = rgid;
 504                 else
 505                         goto error;
 506         }
 507         if (egid != (gid_t) -1) {
 508                 if (old->gid == egid ||
 509                     old->egid == egid ||
 510                     old->sgid == egid ||
 511                     capable(CAP_SETGID))
 512                         new->egid = egid;
 513                 else
 514                         goto error;
 515         }
 516
 517         if (rgid != (gid_t) -1 ||
 518             (egid != (gid_t) -1 && egid != old->gid))
 519                 new->sgid = new->egid;
 520         new->fsgid = new->egid;
 521
 522         return commit_creds(new);
 523
 524 error:
 525         abort_creds(new);
 526         return retval;
 527 }
 528
 529 /*
 530  * setgid() is implemented like SysV w/ SAVED_IDS
 531  *
 532  * SMP: Same implicit races as above.
 533  */
 534 SYSCALL_DEFINE1(setgid, gid_t, gid)
 535 {
 536         const struct cred *old;
 537         struct cred *new;
 538         int retval;
 539
 540         new = prepare_creds();
 541         if (!new)
 542                 return -ENOMEM;
 543         old = current_cred();
 544
 545         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 546         if (retval)
 547                 goto error;
 548
 549         retval = -EPERM;
 550         if (capable(CAP_SETGID))
 551                 new->gid = new->egid = new->sgid = new->fsgid = gid;
 552         else if (gid == old->gid || gid == old->sgid)
 553                 new->egid = new->fsgid = gid;
 554         else
 555                 goto error;
 556
 557         return commit_creds(new);
 558
 559 error:
 560         abort_creds(new);
 561         return retval;
 562 }
 563
 564 /*
 565  * change the user struct in a credentials set to match the new UID
 566  */
 567 static int set_user(struct cred *new)
 568 {
 569         struct user_struct *new_user;
 570
 571         new_user = alloc_uid(current_user_ns(), new->uid);
 572         if (!new_user)
 573                 return -EAGAIN;
 574
 575         if (!task_can_switch_user(new_user, current)) {
 576                 free_uid(new_user);
 577                 return -EINVAL;
 578         }
 579
 580         if (atomic_read(&new_user->processes) >=
 581                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 582                         new_user != INIT_USER) {
 583                 free_uid(new_user);
 584                 return -EAGAIN;
 585         }
 586
 587         free_uid(new->user);
 588         new->user = new_user;
 589         return 0;
 590 }
 591
 592 /*
 593  * Unprivileged users may change the real uid to the effective uid
 594  * or vice versa.  (BSD-style)
 595  *
 596  * If you set the real uid at all, or set the effective uid to a value not
 597  * equal to the real uid, then the saved uid is set to the new effective uid.
 598  *
 599  * This makes it possible for a setuid program to completely drop its
 600  * privileges, which is often a useful assertion to make when you are doing
 601  * a security audit over a program.
 602  *
 603  * The general idea is that a program which uses just setreuid() will be
 604  * 100% compatible with BSD.  A program which uses just setuid() will be
 605  * 100% compatible with POSIX with saved IDs.
 606  */
 607 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 608 {
 609         const struct cred *old;
 610         struct cred *new;
 611         int retval;
 612
 613         new = prepare_creds();
 614         if (!new)
 615                 return -ENOMEM;
 616         old = current_cred();
 617
 618         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 619         if (retval)
 620                 goto error;
 621
 622         retval = -EPERM;
 623         if (ruid != (uid_t) -1) {
 624                 new->uid = ruid;
 625                 if (old->uid != ruid &&
 626                     old->euid != ruid &&
 627                     !capable(CAP_SETUID))
 628                         goto error;
 629         }
 630
 631         if (euid != (uid_t) -1) {
 632                 new->euid = euid;
 633                 if (old->uid != euid &&
 634                     old->euid != euid &&
 635                     old->suid != euid &&
 636                     !capable(CAP_SETUID))
 637                         goto error;
 638         }
 639
 640         if (new->uid != old->uid) {
 641                 retval = set_user(new);
 642                 if (retval < 0)
 643                         goto error;
 644         }
 645         if (ruid != (uid_t) -1 ||
 646             (euid != (uid_t) -1 && euid != old->uid))
 647                 new->suid = new->euid;
 648         new->fsuid = new->euid;
 649
 650         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 651         if (retval < 0)
 652                 goto error;
 653
 654         return commit_creds(new);
 655
 656 error:
 657         abort_creds(new);
 658         return retval;
 659 }
 660
 661 /*
 662  * setuid() is implemented like SysV with SAVED_IDS
 663  *
 664  * Note that SAVED_ID's is deficient in that a setuid root program
 665  * like sendmail, for example, cannot set its uid to be a normal
 666  * user and then switch back, because if you're root, setuid() sets
 667  * the saved uid too.  If you don't like this, blame the bright people
 668  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 669  * will allow a root program to temporarily drop privileges and be able to
 670  * regain them by swapping the real and effective uid.
 671  */
 672 SYSCALL_DEFINE1(setuid, uid_t, uid)
 673 {
 674         const struct cred *old;
 675         struct cred *new;
 676         int retval;
 677
 678         new = prepare_creds();
 679         if (!new)
 680                 return -ENOMEM;
 681         old = current_cred();
 682
 683         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 684         if (retval)
 685                 goto error;
 686
 687         retval = -EPERM;
 688         if (capable(CAP_SETUID)) {
 689                 new->suid = new->uid = uid;
 690                 if (uid != old->uid) {
 691                         retval = set_user(new);
 692                         if (retval < 0)
 693                                 goto error;
 694                 }
 695         } else if (uid != old->uid && uid != new->suid) {
 696                 goto error;
 697         }
 698
 699         new->fsuid = new->euid = uid;
 700
 701         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 702         if (retval < 0)
 703                 goto error;
 704
 705         return commit_creds(new);
 706
 707 error:
 708         abort_creds(new);
 709         return retval;
 710 }
 711
 712
 713 /*
 714  * This function implements a generic ability to update ruid, euid,
 715  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 716  */
 717 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 718 {
 719         const struct cred *old;
 720         struct cred *new;
 721         int retval;
 722
 723         new = prepare_creds();
 724         if (!new)
 725                 return -ENOMEM;
 726
 727         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 728         if (retval)
 729                 goto error;
 730         old = current_cred();
 731
 732         retval = -EPERM;
 733         if (!capable(CAP_SETUID)) {
 734                 if (ruid != (uid_t) -1 && ruid != old->uid &&
 735                     ruid != old->euid  && ruid != old->suid)
 736                         goto error;
 737                 if (euid != (uid_t) -1 && euid != old->uid &&
 738                     euid != old->euid  && euid != old->suid)
 739                         goto error;
 740                 if (suid != (uid_t) -1 && suid != old->uid &&
 741                     suid != old->euid  && suid != old->suid)
 742                         goto error;
 743         }
 744
 745         if (ruid != (uid_t) -1) {
 746                 new->uid = ruid;
 747                 if (ruid != old->uid) {
 748                         retval = set_user(new);
 749                         if (retval < 0)
 750                                 goto error;
 751                 }
 752         }
 753         if (euid != (uid_t) -1)
 754                 new->euid = euid;
 755         if (suid != (uid_t) -1)
 756                 new->suid = suid;
 757         new->fsuid = new->euid;
 758
 759         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 760         if (retval < 0)
 761                 goto error;
 762
 763         return commit_creds(new);
 764
 765 error:
 766         abort_creds(new);
 767         return retval;
 768 }
 769
 770 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
 771 {
 772         const struct cred *cred = current_cred();
 773         int retval;
 774
 775         if (!(retval   = put_user(cred->uid,  ruid)) &&
 776             !(retval   = put_user(cred->euid, euid)))
 777                 retval = put_user(cred->suid, suid);
 778
 779         return retval;
 780 }
 781
 782 /*
 783  * Same as above, but for rgid, egid, sgid.
 784  */
 785 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 786 {
 787         const struct cred *old;
 788         struct cred *new;
 789         int retval;
 790
 791         new = prepare_creds();
 792         if (!new)
 793                 return -ENOMEM;
 794         old = current_cred();
 795
 796         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 797         if (retval)
 798                 goto error;
 799
 800         retval = -EPERM;
 801         if (!capable(CAP_SETGID)) {
 802                 if (rgid != (gid_t) -1 && rgid != old->gid &&
 803                     rgid != old->egid  && rgid != old->sgid)
 804                         goto error;
 805                 if (egid != (gid_t) -1 && egid != old->gid &&
 806                     egid != old->egid  && egid != old->sgid)
 807                         goto error;
 808                 if (sgid != (gid_t) -1 && sgid != old->gid &&
 809                     sgid != old->egid  && sgid != old->sgid)
 810                         goto error;
 811         }
 812
 813         if (rgid != (gid_t) -1)
 814                 new->gid = rgid;
 815         if (egid != (gid_t) -1)
 816                 new->egid = egid;
 817         if (sgid != (gid_t) -1)
 818                 new->sgid = sgid;
 819         new->fsgid = new->egid;
 820
 821         return commit_creds(new);
 822
 823 error:
 824         abort_creds(new);
 825         return retval;
 826 }
 827
 828 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
 829 {
 830         const struct cred *cred = current_cred();
 831         int retval;
 832
 833         if (!(retval   = put_user(cred->gid,  rgid)) &&
 834             !(retval   = put_user(cred->egid, egid)))
 835                 retval = put_user(cred->sgid, sgid);
 836
 837         return retval;
 838 }
 839
 840
 841 /*
 842  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 843  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 844  * whatever uid it wants to). It normally shadows "euid", except when
 845  * explicitly set by setfsuid() or for access..
 846  */
 847 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 848 {
 849         const struct cred *old;
 850         struct cred *new;
 851         uid_t old_fsuid;
 852
 853         new = prepare_creds();
 854         if (!new)
 855                 return current_fsuid();
 856         old = current_cred();
 857         old_fsuid = old->fsuid;
 858
 859         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS) < 0)
 860                 goto error;
 861
 862         if (uid == old->uid  || uid == old->euid  ||
 863             uid == old->suid || uid == old->fsuid ||
 864             capable(CAP_SETUID)) {
 865                 if (uid != old_fsuid) {
 866                         new->fsuid = uid;
 867                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 868                                 goto change_okay;
 869                 }
 870         }
 871
 872 error:
 873         abort_creds(new);
 874         return old_fsuid;
 875
 876 change_okay:
 877         commit_creds(new);
 878         return old_fsuid;
 879 }
 880
 881 /*
 882  * Samma på svenska..
 883  */
 884 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 885 {
 886         const struct cred *old;
 887         struct cred *new;
 888         gid_t old_fsgid;
 889
 890         new = prepare_creds();
 891         if (!new)
 892                 return current_fsgid();
 893         old = current_cred();
 894         old_fsgid = old->fsgid;
 895
 896         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 897                 goto error;
 898
 899         if (gid == old->gid  || gid == old->egid  ||
 900             gid == old->sgid || gid == old->fsgid ||
 901             capable(CAP_SETGID)) {
 902                 if (gid != old_fsgid) {
 903                         new->fsgid = gid;
 904                         goto change_okay;
 905                 }
 906         }
 907
 908 error:
 909         abort_creds(new);
 910         return old_fsgid;
 911
 912 change_okay:
 913         commit_creds(new);
 914         return old_fsgid;
 915 }
 916
 917 void do_sys_times(struct tms *tms)
 918 {
 919         struct task_cputime cputime;
 920         cputime_t cutime, cstime;
 921
 922         thread_group_cputime(current, &cputime);
 923         spin_lock_irq(&current->sighand->siglock);
 924         cutime = current->signal->cutime;
 925         cstime = current->signal->cstime;
 926         spin_unlock_irq(&current->sighand->siglock);
 927         tms->tms_utime = cputime_to_clock_t(cputime.utime);
 928         tms->tms_stime = cputime_to_clock_t(cputime.stime);
 929         tms->tms_cutime = cputime_to_clock_t(cutime);
 930         tms->tms_cstime = cputime_to_clock_t(cstime);
 931 }
 932
 933 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 934 {
 935         if (tbuf) {
 936                 struct tms tmp;
 937
 938                 do_sys_times(&tmp);
 939                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 940                         return -EFAULT;
 941         }
 942         force_successful_syscall_return();
 943         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 944 }
 945
 946 /*
 947  * This needs some heavy checking ...
 948  * I just haven't the stomach for it. I also don't fully
 949  * understand sessions/pgrp etc. Let somebody who does explain it.
 950  *
 951  * OK, I think I have the protection semantics right.... this is really
 952  * only important on a multi-user system anyway, to make sure one user
 953  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 954  *
 955  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 956  * LBT 04.03.94
 957  */
 958 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 959 {
 960         struct task_struct *p;
 961         struct task_struct *group_leader = current->group_leader;
 962         struct pid *pgrp;
 963         int err;
 964
 965         if (!pid)
 966                 pid = task_pid_vnr(group_leader);
 967         if (!pgid)
 968                 pgid = pid;
 969         if (pgid < 0)
 970                 return -EINVAL;
 971
 972         /* From this point forward we keep holding onto the tasklist lock
 973          * so that our parent does not change from under us. -DaveM
 974          */
 975         write_lock_irq(&tasklist_lock);
 976
 977         err = -ESRCH;
 978         p = find_task_by_vpid(pid);
 979         if (!p)
 980                 goto out;
 981
 982         err = -EINVAL;
 983         if (!thread_group_leader(p))
 984                 goto out;
 985
 986         if (same_thread_group(p->real_parent, group_leader)) {
 987                 err = -EPERM;
 988                 if (task_session(p) != task_session(group_leader))
 989                         goto out;
 990                 err = -EACCES;
 991                 if (p->did_exec)
 992                         goto out;
 993         } else {
 994                 err = -ESRCH;
 995                 if (p != group_leader)
 996                         goto out;
 997         }
 998
 999         err = -EPERM;
1000         if (p->signal->leader)
1001                 goto out;
1002
1003         pgrp = task_pid(p);
1004         if (pgid != pid) {
1005                 struct task_struct *g;
1006
1007                 pgrp = find_vpid(pgid);
1008                 g = pid_task(pgrp, PIDTYPE_PGID);
1009                 if (!g || task_session(g) != task_session(group_leader))
1010                         goto out;
1011         }
1012
1013         err = security_task_setpgid(p, pgid);
1014         if (err)
1015                 goto out;
1016
1017         if (task_pgrp(p) != pgrp)
1018                 change_pid(p, PIDTYPE_PGID, pgrp);
1019
1020         err = 0;
1021 out:
1022         /* All paths lead to here, thus we are safe. -DaveM */
1023         write_unlock_irq(&tasklist_lock);
1024         return err;
1025 }
1026
1027 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1028 {
1029         struct task_struct *p;
1030         struct pid *grp;
1031         int retval;
1032
1033         rcu_read_lock();
1034         if (!pid)
1035                 grp = task_pgrp(current);
1036         else {
1037                 retval = -ESRCH;
1038                 p = find_task_by_vpid(pid);
1039                 if (!p)
1040                         goto out;
1041                 grp = task_pgrp(p);
1042                 if (!grp)
1043                         goto out;
1044
1045                 retval = security_task_getpgid(p);
1046                 if (retval)
1047                         goto out;
1048         }
1049         retval = pid_vnr(grp);
1050 out:
1051         rcu_read_unlock();
1052         return retval;
1053 }
1054
1055 #ifdef __ARCH_WANT_SYS_GETPGRP
1056
1057 SYSCALL_DEFINE0(getpgrp)
1058 {
1059         return sys_getpgid(0);
1060 }
1061
1062 #endif
1063
1064 SYSCALL_DEFINE1(getsid, pid_t, pid)
1065 {
1066         struct task_struct *p;
1067         struct pid *sid;
1068         int retval;
1069
1070         rcu_read_lock();
1071         if (!pid)
1072                 sid = task_session(current);
1073         else {
1074                 retval = -ESRCH;
1075                 p = find_task_by_vpid(pid);
1076                 if (!p)
1077                         goto out;
1078                 sid = task_session(p);
1079                 if (!sid)
1080                         goto out;
1081
1082                 retval = security_task_getsid(p);
1083                 if (retval)
1084                         goto out;
1085         }
1086         retval = pid_vnr(sid);
1087 out:
1088         rcu_read_unlock();
1089         return retval;
1090 }
1091
1092 SYSCALL_DEFINE0(setsid)
1093 {
1094         struct task_struct *group_leader = current->group_leader;
1095         struct pid *sid = task_pid(group_leader);
1096         pid_t session = pid_vnr(sid);
1097         int err = -EPERM;
1098
1099         write_lock_irq(&tasklist_lock);
1100         /* Fail if I am already a session leader */
1101         if (group_leader->signal->leader)
1102                 goto out;
1103
1104         /* Fail if a process group id already exists that equals the
1105          * proposed session id.
1106          */
1107         if (pid_task(sid, PIDTYPE_PGID))
1108                 goto out;
1109
1110         group_leader->signal->leader = 1;
1111         __set_special_pids(sid);
1112
1113         proc_clear_tty(group_leader);
1114
1115         err = session;
1116 out:
1117         write_unlock_irq(&tasklist_lock);
1118         return err;
1119 }
1120
1121 /*
1122  * Supplementary group IDs
1123  */
1124
1125 /* init to 2 - one for init_task, one to ensure it is never freed */
1126 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1127
1128 struct group_info *groups_alloc(int gidsetsize)
1129 {
1130         struct group_info *group_info;
1131         int nblocks;
1132         int i;
1133
1134         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1135         /* Make sure we always allocate at least one indirect block pointer */
1136         nblocks = nblocks ? : 1;
1137         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1138         if (!group_info)
1139                 return NULL;
1140         group_info->ngroups = gidsetsize;
1141         group_info->nblocks = nblocks;
1142         atomic_set(&group_info->usage, 1);
1143
1144         if (gidsetsize <= NGROUPS_SMALL)
1145                 group_info->blocks[0] = group_info->small_block;
1146         else {
1147                 for (i = 0; i < nblocks; i++) {
1148                         gid_t *b;
1149                         b = (void *)__get_free_page(GFP_USER);
1150                         if (!b)
1151                                 goto out_undo_partial_alloc;
1152                         group_info->blocks[i] = b;
1153                 }
1154         }
1155         return group_info;
1156
1157 out_undo_partial_alloc:
1158         while (--i >= 0) {
1159                 free_page((unsigned long)group_info->blocks[i]);
1160         }
1161         kfree(group_info);
1162         return NULL;
1163 }
1164
1165 EXPORT_SYMBOL(groups_alloc);
1166
1167 void groups_free(struct group_info *group_info)
1168 {
1169         if (group_info->blocks[0] != group_info->small_block) {
1170                 int i;
1171                 for (i = 0; i < group_info->nblocks; i++)
1172                         free_page((unsigned long)group_info->blocks[i]);
1173         }
1174         kfree(group_info);
1175 }
1176
1177 EXPORT_SYMBOL(groups_free);
1178
1179 /* export the group_info to a user-space array */
1180 static int groups_to_user(gid_t __user *grouplist,
1181                           const struct group_info *group_info)
1182 {
1183         int i;
1184         unsigned int count = group_info->ngroups;
1185
1186         for (i = 0; i < group_info->nblocks; i++) {
1187                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1188                 unsigned int len = cp_count * sizeof(*grouplist);
1189
1190                 if (copy_to_user(grouplist, group_info->blocks[i], len))
1191                         return -EFAULT;
1192
1193                 grouplist += NGROUPS_PER_BLOCK;
1194                 count -= cp_count;
1195         }
1196         return 0;
1197 }
1198
1199 /* fill a group_info from a user-space array - it must be allocated already */
1200 static int groups_from_user(struct group_info *group_info,
1201     gid_t __user *grouplist)
1202 {
1203         int i;
1204         unsigned int count = group_info->ngroups;
1205
1206         for (i = 0; i < group_info->nblocks; i++) {
1207                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1208                 unsigned int len = cp_count * sizeof(*grouplist);
1209
1210                 if (copy_from_user(group_info->blocks[i], grouplist, len))
1211                         return -EFAULT;
1212
1213                 grouplist += NGROUPS_PER_BLOCK;
1214                 count -= cp_count;
1215         }
1216         return 0;
1217 }
1218
1219 /* a simple Shell sort */
1220 static void groups_sort(struct group_info *group_info)
1221 {
1222         int base, max, stride;
1223         int gidsetsize = group_info->ngroups;
1224
1225         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1226                 ; /* nothing */
1227         stride /= 3;
1228
1229         while (stride) {
1230                 max = gidsetsize - stride;
1231                 for (base = 0; base < max; base++) {
1232                         int left = base;
1233                         int right = left + stride;
1234                         gid_t tmp = GROUP_AT(group_info, right);
1235
1236                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1237                                 GROUP_AT(group_info, right) =
1238                                     GROUP_AT(group_info, left);
1239                                 right = left;
1240                                 left -= stride;
1241                         }
1242                         GROUP_AT(group_info, right) = tmp;
1243                 }
1244                 stride /= 3;
1245         }
1246 }
1247
1248 /* a simple bsearch */
1249 int groups_search(const struct group_info *group_info, gid_t grp)
1250 {
1251         unsigned int left, right;
1252
1253         if (!group_info)
1254                 return 0;
1255
1256         left = 0;
1257         right = group_info->ngroups;
1258         while (left < right) {
1259                 unsigned int mid = (left+right)/2;
1260                 int cmp = grp - GROUP_AT(group_info, mid);
1261                 if (cmp > 0)
1262                         left = mid + 1;
1263                 else if (cmp < 0)
1264                         right = mid;
1265                 else
1266                         return 1;
1267         }
1268         return 0;
1269 }
1270
1271 /**
1272  * set_groups - Change a group subscription in a set of credentials
1273  * @new: The newly prepared set of credentials to alter
1274  * @group_info: The group list to install
1275  *
1276  * Validate a group subscription and, if valid, insert it into a set
1277  * of credentials.
1278  */
1279 int set_groups(struct cred *new, struct group_info *group_info)
1280 {
1281         int retval;
1282
1283         retval = security_task_setgroups(group_info);
1284         if (retval)
1285                 return retval;
1286
1287         put_group_info(new->group_info);
1288         groups_sort(group_info);
1289         get_group_info(group_info);
1290         new->group_info = group_info;
1291         return 0;
1292 }
1293
1294 EXPORT_SYMBOL(set_groups);
1295
1296 /**
1297  * set_current_groups - Change current's group subscription
1298  * @group_info: The group list to impose
1299  *
1300  * Validate a group subscription and, if valid, impose it upon current's task
1301  * security record.
1302  */
1303 int set_current_groups(struct group_info *group_info)
1304 {
1305         struct cred *new;
1306         int ret;
1307
1308         new = prepare_creds();
1309         if (!new)
1310                 return -ENOMEM;
1311
1312         ret = set_groups(new, group_info);
1313         if (ret < 0) {
1314                 abort_creds(new);
1315                 return ret;
1316         }
1317
1318         return commit_creds(new);
1319 }
1320
1321 EXPORT_SYMBOL(set_current_groups);
1322
1323 SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
1324 {
1325         const struct cred *cred = current_cred();
1326         int i;
1327
1328         if (gidsetsize < 0)
1329                 return -EINVAL;
1330
1331         /* no need to grab task_lock here; it cannot change */
1332         i = cred->group_info->ngroups;
1333         if (gidsetsize) {
1334                 if (i > gidsetsize) {
1335                         i = -EINVAL;
1336                         goto out;
1337                 }
1338                 if (groups_to_user(grouplist, cred->group_info)) {
1339                         i = -EFAULT;
1340                         goto out;
1341                 }
1342         }
1343 out:
1344         return i;
1345 }
1346
1347 /*
1348  *      SMP: Our groups are copy-on-write. We can set them safely
1349  *      without another task interfering.
1350  */
1351
1352 SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
1353 {
1354         struct group_info *group_info;
1355         int retval;
1356
1357         if (!capable(CAP_SETGID))
1358                 return -EPERM;
1359         if ((unsigned)gidsetsize > NGROUPS_MAX)
1360                 return -EINVAL;
1361
1362         group_info = groups_alloc(gidsetsize);
1363         if (!group_info)
1364                 return -ENOMEM;
1365         retval = groups_from_user(group_info, grouplist);
1366         if (retval) {
1367                 put_group_info(group_info);
1368                 return retval;
1369         }
1370
1371         retval = set_current_groups(group_info);
1372         put_group_info(group_info);
1373
1374         return retval;
1375 }
1376
1377 /*
1378  * Check whether we're fsgid/egid or in the supplemental group..
1379  */
1380 int in_group_p(gid_t grp)
1381 {
1382         const struct cred *cred = current_cred();
1383         int retval = 1;
1384
1385         if (grp != cred->fsgid)
1386                 retval = groups_search(cred->group_info, grp);
1387         return retval;
1388 }
1389
1390 EXPORT_SYMBOL(in_group_p);
1391
1392 int in_egroup_p(gid_t grp)
1393 {
1394         const struct cred *cred = current_cred();
1395         int retval = 1;
1396
1397         if (grp != cred->egid)
1398                 retval = groups_search(cred->group_info, grp);
1399         return retval;
1400 }
1401
1402 EXPORT_SYMBOL(in_egroup_p);
1403
1404 DECLARE_RWSEM(uts_sem);
1405
1406 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1407 {
1408         int errno = 0;
1409
1410         down_read(&uts_sem);
1411         if (copy_to_user(name, utsname(), sizeof *name))
1412                 errno = -EFAULT;
1413         up_read(&uts_sem);
1414         return errno;
1415 }
1416
1417 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1418 {
1419         int errno;
1420         char tmp[__NEW_UTS_LEN];
1421
1422         if (!capable(CAP_SYS_ADMIN))
1423                 return -EPERM;
1424         if (len < 0 || len > __NEW_UTS_LEN)
1425                 return -EINVAL;
1426         down_write(&uts_sem);
1427         errno = -EFAULT;
1428         if (!copy_from_user(tmp, name, len)) {
1429                 struct new_utsname *u = utsname();
1430
1431                 memcpy(u->nodename, tmp, len);
1432                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1433                 errno = 0;
1434         }
1435         up_write(&uts_sem);
1436         return errno;
1437 }
1438
1439 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1440
1441 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1442 {
1443         int i, errno;
1444         struct new_utsname *u;
1445
1446         if (len < 0)
1447                 return -EINVAL;
1448         down_read(&uts_sem);
1449         u = utsname();
1450         i = 1 + strlen(u->nodename);
1451         if (i > len)
1452                 i = len;
1453         errno = 0;
1454         if (copy_to_user(name, u->nodename, i))
1455                 errno = -EFAULT;
1456         up_read(&uts_sem);
1457         return errno;
1458 }
1459
1460 #endif
1461
1462 /*
1463  * Only setdomainname; getdomainname can be implemented by calling
1464  * uname()
1465  */
1466 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1467 {
1468         int errno;
1469         char tmp[__NEW_UTS_LEN];
1470
1471         if (!capable(CAP_SYS_ADMIN))
1472                 return -EPERM;
1473         if (len < 0 || len > __NEW_UTS_LEN)
1474                 return -EINVAL;
1475
1476         down_write(&uts_sem);
1477         errno = -EFAULT;
1478         if (!copy_from_user(tmp, name, len)) {
1479                 struct new_utsname *u = utsname();
1480
1481                 memcpy(u->domainname, tmp, len);
1482                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1483                 errno = 0;
1484         }
1485         up_write(&uts_sem);
1486         return errno;
1487 }
1488
1489 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1490 {
1491         if (resource >= RLIM_NLIMITS)
1492                 return -EINVAL;
1493         else {
1494                 struct rlimit value;
1495                 task_lock(current->group_leader);
1496                 value = current->signal->rlim[resource];
1497                 task_unlock(current->group_leader);
1498                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1499         }
1500 }
1501
1502 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1503
1504 /*
1505  *      Back compatibility for getrlimit. Needed for some apps.
1506  */
1507
1508 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1509                 struct rlimit __user *, rlim)
1510 {
1511         struct rlimit x;
1512         if (resource >= RLIM_NLIMITS)
1513                 return -EINVAL;
1514
1515         task_lock(current->group_leader);
1516         x = current->signal->rlim[resource];
1517         task_unlock(current->group_leader);
1518         if (x.rlim_cur > 0x7FFFFFFF)
1519                 x.rlim_cur = 0x7FFFFFFF;
1520         if (x.rlim_max > 0x7FFFFFFF)
1521                 x.rlim_max = 0x7FFFFFFF;
1522         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1523 }
1524
1525 #endif
1526
1527 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1528 {
1529         struct rlimit new_rlim, *old_rlim;
1530         int retval;
1531
1532         if (resource >= RLIM_NLIMITS)
1533                 return -EINVAL;
1534         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1535                 return -EFAULT;
1536         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1537                 return -EINVAL;
1538         old_rlim = current->signal->rlim + resource;
1539         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1540             !capable(CAP_SYS_RESOURCE))
1541                 return -EPERM;
1542         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1543                 return -EPERM;
1544
1545         retval = security_task_setrlimit(resource, &new_rlim);
1546         if (retval)
1547                 return retval;
1548
1549         if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1550                 /*
1551                  * The caller is asking for an immediate RLIMIT_CPU
1552                  * expiry.  But we use the zero value to mean "it was
1553                  * never set".  So let's cheat and make it one second
1554                  * instead
1555                  */
1556                 new_rlim.rlim_cur = 1;
1557         }
1558
1559         task_lock(current->group_leader);
1560         *old_rlim = new_rlim;
1561         task_unlock(current->group_leader);
1562
1563         if (resource != RLIMIT_CPU)
1564                 goto out;
1565
1566         /*
1567          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1568          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1569          * very long-standing error, and fixing it now risks breakage of
1570          * applications, so we live with it
1571          */
1572         if (new_rlim.rlim_cur == RLIM_INFINITY)
1573                 goto out;
1574
1575         update_rlimit_cpu(new_rlim.rlim_cur);
1576 out:
1577         return 0;
1578 }
1579
1580 /*
1581  * It would make sense to put struct rusage in the task_struct,
1582  * except that would make the task_struct be *really big*.  After
1583  * task_struct gets moved into malloc'ed memory, it would
1584  * make sense to do this.  It will make moving the rest of the information
1585  * a lot simpler!  (Which we're not doing right now because we're not
1586  * measuring them yet).
1587  *
1588  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1589  * races with threads incrementing their own counters.  But since word
1590  * reads are atomic, we either get new values or old values and we don't
1591  * care which for the sums.  We always take the siglock to protect reading
1592  * the c* fields from p->signal from races with exit.c updating those
1593  * fields when reaping, so a sample either gets all the additions of a
1594  * given child after it's reaped, or none so this sample is before reaping.
1595  *
1596  * Locking:
1597  * We need to take the siglock for CHILDEREN, SELF and BOTH
1598  * for  the cases current multithreaded, non-current single threaded
1599  * non-current multithreaded.  Thread traversal is now safe with
1600  * the siglock held.
1601  * Strictly speaking, we donot need to take the siglock if we are current and
1602  * single threaded,  as no one else can take our signal_struct away, no one
1603  * else can  reap the  children to update signal->c* counters, and no one else
1604  * can race with the signal-> fields. If we do not take any lock, the
1605  * signal-> fields could be read out of order while another thread was just
1606  * exiting. So we should  place a read memory barrier when we avoid the lock.
1607  * On the writer side,  write memory barrier is implied in  __exit_signal
1608  * as __exit_signal releases  the siglock spinlock after updating the signal->
1609  * fields. But we don't do this yet to keep things simple.
1610  *
1611  */
1612
1613 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1614 {
1615         r->ru_nvcsw += t->nvcsw;
1616         r->ru_nivcsw += t->nivcsw;
1617         r->ru_minflt += t->min_flt;
1618         r->ru_majflt += t->maj_flt;
1619         r->ru_inblock += task_io_get_inblock(t);
1620         r->ru_oublock += task_io_get_oublock(t);
1621 }
1622
1623 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1624 {
1625         struct task_struct *t;
1626         unsigned long flags;
1627         cputime_t utime, stime;
1628         struct task_cputime cputime;
1629
1630         memset((char *) r, 0, sizeof *r);
1631         utime = stime = cputime_zero;
1632
1633         if (who == RUSAGE_THREAD) {
1634                 utime = task_utime(current);
1635                 stime = task_stime(current);
1636                 accumulate_thread_rusage(p, r);
1637                 goto out;
1638         }
1639
1640         if (!lock_task_sighand(p, &flags))
1641                 return;
1642
1643         switch (who) {
1644                 case RUSAGE_BOTH:
1645                 case RUSAGE_CHILDREN:
1646                         utime = p->signal->cutime;
1647                         stime = p->signal->cstime;
1648                         r->ru_nvcsw = p->signal->cnvcsw;
1649                         r->ru_nivcsw = p->signal->cnivcsw;
1650                         r->ru_minflt = p->signal->cmin_flt;
1651                         r->ru_majflt = p->signal->cmaj_flt;
1652                         r->ru_inblock = p->signal->cinblock;
1653                         r->ru_oublock = p->signal->coublock;
1654
1655                         if (who == RUSAGE_CHILDREN)
1656                                 break;
1657
1658                 case RUSAGE_SELF:
1659                         thread_group_cputime(p, &cputime);
1660                         utime = cputime_add(utime, cputime.utime);
1661                         stime = cputime_add(stime, cputime.stime);
1662                         r->ru_nvcsw += p->signal->nvcsw;
1663                         r->ru_nivcsw += p->signal->nivcsw;
1664                         r->ru_minflt += p->signal->min_flt;
1665                         r->ru_majflt += p->signal->maj_flt;
1666                         r->ru_inblock += p->signal->inblock;
1667                         r->ru_oublock += p->signal->oublock;
1668                         t = p;
1669                         do {
1670                                 accumulate_thread_rusage(t, r);
1671                                 t = next_thread(t);
1672                         } while (t != p);
1673                         break;
1674
1675                 default:
1676                         BUG();
1677         }
1678         unlock_task_sighand(p, &flags);
1679
1680 out:
1681         cputime_to_timeval(utime, &r->ru_utime);
1682         cputime_to_timeval(stime, &r->ru_stime);
1683 }
1684
1685 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1686 {
1687         struct rusage r;
1688         k_getrusage(p, who, &r);
1689         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1690 }
1691
1692 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1693 {
1694         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1695             who != RUSAGE_THREAD)
1696                 return -EINVAL;
1697         return getrusage(current, who, ru);
1698 }
1699
1700 SYSCALL_DEFINE1(umask, int, mask)
1701 {
1702         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1703         return mask;
1704 }
1705
1706 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1707                 unsigned long, arg4, unsigned long, arg5)
1708 {
1709         struct task_struct *me = current;
1710         unsigned char comm[sizeof(me->comm)];
1711         long error;
1712
1713         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1714         if (error != -ENOSYS)
1715                 return error;
1716
1717         error = 0;
1718         switch (option) {
1719                 case PR_SET_PDEATHSIG:
1720                         if (!valid_signal(arg2)) {
1721                                 error = -EINVAL;
1722                                 break;
1723                         }
1724                         me->pdeath_signal = arg2;
1725                         error = 0;
1726                         break;
1727                 case PR_GET_PDEATHSIG:
1728                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1729                         break;
1730                 case PR_GET_DUMPABLE:
1731                         error = get_dumpable(me->mm);
1732                         break;
1733                 case PR_SET_DUMPABLE:
1734                         if (arg2 < 0 || arg2 > 1) {
1735                                 error = -EINVAL;
1736                                 break;
1737                         }
1738                         set_dumpable(me->mm, arg2);
1739                         error = 0;
1740                         break;
1741
1742                 case PR_SET_UNALIGN:
1743                         error = SET_UNALIGN_CTL(me, arg2);
1744                         break;
1745                 case PR_GET_UNALIGN:
1746                         error = GET_UNALIGN_CTL(me, arg2);
1747                         break;
1748                 case PR_SET_FPEMU:
1749                         error = SET_FPEMU_CTL(me, arg2);
1750                         break;
1751                 case PR_GET_FPEMU:
1752                         error = GET_FPEMU_CTL(me, arg2);
1753                         break;
1754                 case PR_SET_FPEXC:
1755                         error = SET_FPEXC_CTL(me, arg2);
1756                         break;
1757                 case PR_GET_FPEXC:
1758                         error = GET_FPEXC_CTL(me, arg2);
1759                         break;
1760                 case PR_GET_TIMING:
1761                         error = PR_TIMING_STATISTICAL;
1762                         break;
1763                 case PR_SET_TIMING:
1764                         if (arg2 != PR_TIMING_STATISTICAL)
1765                                 error = -EINVAL;
1766                         else
1767                                 error = 0;
1768                         break;
1769
1770                 case PR_SET_NAME:
1771                         comm[sizeof(me->comm)-1] = 0;
1772                         if (strncpy_from_user(comm, (char __user *)arg2,
1773                                               sizeof(me->comm) - 1) < 0)
1774                                 return -EFAULT;
1775                         set_task_comm(me, comm);
1776                         return 0;
1777                 case PR_GET_NAME:
1778                         get_task_comm(comm, me);
1779                         if (copy_to_user((char __user *)arg2, comm,
1780                                          sizeof(comm)))
1781                                 return -EFAULT;
1782                         return 0;
1783                 case PR_GET_ENDIAN:
1784                         error = GET_ENDIAN(me, arg2);
1785                         break;
1786                 case PR_SET_ENDIAN:
1787                         error = SET_ENDIAN(me, arg2);
1788                         break;
1789
1790                 case PR_GET_SECCOMP:
1791                         error = prctl_get_seccomp();
1792                         break;
1793                 case PR_SET_SECCOMP:
1794                         error = prctl_set_seccomp(arg2);
1795                         break;
1796                 case PR_GET_TSC:
1797                         error = GET_TSC_CTL(arg2);
1798                         break;
1799                 case PR_SET_TSC:
1800                         error = SET_TSC_CTL(arg2);
1801                         break;
1802                 case PR_GET_TIMERSLACK:
1803                         error = current->timer_slack_ns;
1804                         break;
1805                 case PR_SET_TIMERSLACK:
1806                         if (arg2 <= 0)
1807                                 current->timer_slack_ns =
1808                                         current->default_timer_slack_ns;
1809                         else
1810                                 current->timer_slack_ns = arg2;
1811                         error = 0;
1812                         break;
1813                 default:
1814                         error = -EINVAL;
1815                         break;
1816         }
1817         return error;
1818 }
1819
1820 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1821                 struct getcpu_cache __user *, unused)
1822 {
1823         int err = 0;
1824         int cpu = raw_smp_processor_id();
1825         if (cpup)
1826                 err |= put_user(cpu, cpup);
1827         if (nodep)
1828                 err |= put_user(cpu_to_node(cpu), nodep);
1829         return err ? -EFAULT : 0;
1830 }
1831
1832 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1833
1834 static void argv_cleanup(char **argv, char **envp)
1835 {
1836         argv_free(argv);
1837 }
1838
1839 /**
1840  * orderly_poweroff - Trigger an orderly system poweroff
1841  * @force: force poweroff if command execution fails
1842  *
1843  * This may be called from any context to trigger a system shutdown.
1844  * If the orderly shutdown fails, it will force an immediate shutdown.
1845  */
1846 int orderly_poweroff(bool force)
1847 {
1848         int argc;
1849         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1850         static char *envp[] = {
1851                 "HOME=/",
1852                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1853                 NULL
1854         };
1855         int ret = -ENOMEM;
1856         struct subprocess_info *info;
1857
1858         if (argv == NULL) {
1859                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1860                        __func__, poweroff_cmd);
1861                 goto out;
1862         }
1863
1864         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1865         if (info == NULL) {
1866                 argv_free(argv);
1867                 goto out;
1868         }
1869
1870         call_usermodehelper_setcleanup(info, argv_cleanup);
1871
1872         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1873
1874   out:
1875         if (ret && force) {
1876                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1877                        "forcing the issue\n");
1878
1879                 /* I guess this should try to kick off some daemon to
1880                    sync and poweroff asap.  Or not even bother syncing
1881                    if we're doing an emergency shutdown? */
1882                 emergency_sync();
1883                 kernel_power_off();
1884         }
1885
1886         return ret;
1887 }
1888 EXPORT_SYMBOL_GPL(orderly_poweroff);