kernel/sys.c

   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/module.h>
   9 #include <linux/mm.h>
  10 #include <linux/utsname.h>
  11 #include <linux/mman.h>
  12 #include <linux/smp_lock.h>
  13 #include <linux/notifier.h>
  14 #include <linux/reboot.h>
  15 #include <linux/prctl.h>
  16 #include <linux/init.h>
  17 #include <linux/highuid.h>
  18 #include <linux/fs.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kexec.h>
  21 #include <linux/workqueue.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
  32 #include <linux/compat.h>
  33 #include <linux/syscalls.h>
  34
  35 #include <asm/uaccess.h>
  36 #include <asm/io.h>
  37 #include <asm/unistd.h>
  38
  39 #ifndef SET_UNALIGN_CTL
  40 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  41 #endif
  42 #ifndef GET_UNALIGN_CTL
  43 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  44 #endif
  45 #ifndef SET_FPEMU_CTL
  46 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  47 #endif
  48 #ifndef GET_FPEMU_CTL
  49 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  50 #endif
  51 #ifndef SET_FPEXC_CTL
  52 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  53 #endif
  54 #ifndef GET_FPEXC_CTL
  55 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  56 #endif
  57
  58 /*
  59  * this is where the system-wide overflow UID and GID are defined, for
  60  * architectures that now have 32-bit UID/GID but didn't in the past
  61  */
  62
  63 int overflowuid = DEFAULT_OVERFLOWUID;
  64 int overflowgid = DEFAULT_OVERFLOWGID;
  65
  66 #ifdef CONFIG_UID16
  67 EXPORT_SYMBOL(overflowuid);
  68 EXPORT_SYMBOL(overflowgid);
  69 #endif
  70
  71 /*
  72  * the same as above, but for filesystems which can only store a 16-bit
  73  * UID and GID. as such, this is needed on all architectures
  74  */
  75
  76 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  77 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  78
  79 EXPORT_SYMBOL(fs_overflowuid);
  80 EXPORT_SYMBOL(fs_overflowgid);
  81
  82 /*
  83  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
  84  */
  85
  86 int C_A_D = 1;
  87 int cad_pid = 1;
  88
  89 /*
  90  *      Notifier list for kernel code which wants to be called
  91  *      at shutdown. This is used to stop any idling DMA operations
  92  *      and the like.
  93  */
  94
  95 static struct notifier_block *reboot_notifier_list;
  96 static DEFINE_RWLOCK(notifier_lock);
  97
  98 /**
  99  *      notifier_chain_register - Add notifier to a notifier chain
 100  *      @list: Pointer to root list pointer
 101  *      @n: New entry in notifier chain
 102  *
 103  *      Adds a notifier to a notifier chain.
 104  *
 105  *      Currently always returns zero.
 106  */
 107
 108 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
 109 {
 110         write_lock(&notifier_lock);
 111         while(*list)
 112         {
 113                 if(n->priority > (*list)->priority)
 114                         break;
 115                 list= &((*list)->next);
 116         }
 117         n->next = *list;
 118         *list=n;
 119         write_unlock(&notifier_lock);
 120         return 0;
 121 }
 122
 123 EXPORT_SYMBOL(notifier_chain_register);
 124
 125 /**
 126  *      notifier_chain_unregister - Remove notifier from a notifier chain
 127  *      @nl: Pointer to root list pointer
 128  *      @n: New entry in notifier chain
 129  *
 130  *      Removes a notifier from a notifier chain.
 131  *
 132  *      Returns zero on success, or %-ENOENT on failure.
 133  */
 134
 135 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
 136 {
 137         write_lock(&notifier_lock);
 138         while((*nl)!=NULL)
 139         {
 140                 if((*nl)==n)
 141                 {
 142                         *nl=n->next;
 143                         write_unlock(&notifier_lock);
 144                         return 0;
 145                 }
 146                 nl=&((*nl)->next);
 147         }
 148         write_unlock(&notifier_lock);
 149         return -ENOENT;
 150 }
 151
 152 EXPORT_SYMBOL(notifier_chain_unregister);
 153
 154 /**
 155  *      notifier_call_chain - Call functions in a notifier chain
 156  *      @n: Pointer to root pointer of notifier chain
 157  *      @val: Value passed unmodified to notifier function
 158  *      @v: Pointer passed unmodified to notifier function
 159  *
 160  *      Calls each function in a notifier chain in turn.
 161  *
 162  *      If the return value of the notifier can be and'd
 163  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
 164  *      will return immediately, with the return value of
 165  *      the notifier function which halted execution.
 166  *      Otherwise, the return value is the return value
 167  *      of the last notifier function called.
 168  */
 169
 170 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
 171 {
 172         int ret=NOTIFY_DONE;
 173         struct notifier_block *nb = *n;
 174
 175         while(nb)
 176         {
 177                 ret=nb->notifier_call(nb,val,v);
 178                 if(ret&NOTIFY_STOP_MASK)
 179                 {
 180                         return ret;
 181                 }
 182                 nb=nb->next;
 183         }
 184         return ret;
 185 }
 186
 187 EXPORT_SYMBOL(notifier_call_chain);
 188
 189 /**
 190  *      register_reboot_notifier - Register function to be called at reboot time
 191  *      @nb: Info about notifier function to be called
 192  *
 193  *      Registers a function with the list of functions
 194  *      to be called at reboot time.
 195  *
 196  *      Currently always returns zero, as notifier_chain_register
 197  *      always returns zero.
 198  */
 199
 200 int register_reboot_notifier(struct notifier_block * nb)
 201 {
 202         return notifier_chain_register(&reboot_notifier_list, nb);
 203 }
 204
 205 EXPORT_SYMBOL(register_reboot_notifier);
 206
 207 /**
 208  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
 209  *      @nb: Hook to be unregistered
 210  *
 211  *      Unregisters a previously registered reboot
 212  *      notifier function.
 213  *
 214  *      Returns zero on success, or %-ENOENT on failure.
 215  */
 216
 217 int unregister_reboot_notifier(struct notifier_block * nb)
 218 {
 219         return notifier_chain_unregister(&reboot_notifier_list, nb);
 220 }
 221
 222 EXPORT_SYMBOL(unregister_reboot_notifier);
 223
 224 static int set_one_prio(struct task_struct *p, int niceval, int error)
 225 {
 226         int no_nice;
 227
 228         if (p->uid != current->euid &&
 229                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 230                 error = -EPERM;
 231                 goto out;
 232         }
 233         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 234                 error = -EACCES;
 235                 goto out;
 236         }
 237         no_nice = security_task_setnice(p, niceval);
 238         if (no_nice) {
 239                 error = no_nice;
 240                 goto out;
 241         }
 242         if (error == -ESRCH)
 243                 error = 0;
 244         set_user_nice(p, niceval);
 245 out:
 246         return error;
 247 }
 248
 249 asmlinkage long sys_setpriority(int which, int who, int niceval)
 250 {
 251         struct task_struct *g, *p;
 252         struct user_struct *user;
 253         int error = -EINVAL;
 254
 255         if (which > 2 || which < 0)
 256                 goto out;
 257
 258         /* normalize: avoid signed division (rounding problems) */
 259         error = -ESRCH;
 260         if (niceval < -20)
 261                 niceval = -20;
 262         if (niceval > 19)
 263                 niceval = 19;
 264
 265         read_lock(&tasklist_lock);
 266         switch (which) {
 267                 case PRIO_PROCESS:
 268                         if (!who)
 269                                 who = current->pid;
 270                         p = find_task_by_pid(who);
 271                         if (p)
 272                                 error = set_one_prio(p, niceval, error);
 273                         break;
 274                 case PRIO_PGRP:
 275                         if (!who)
 276                                 who = process_group(current);
 277                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 278                                 error = set_one_prio(p, niceval, error);
 279                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 280                         break;
 281                 case PRIO_USER:
 282                         user = current->user;
 283                         if (!who)
 284                                 who = current->uid;
 285                         else
 286                                 if ((who != current->uid) && !(user = find_user(who)))
 287                                         goto out_unlock;        /* No processes for this user */
 288
 289                         do_each_thread(g, p)
 290                                 if (p->uid == who)
 291                                         error = set_one_prio(p, niceval, error);
 292                         while_each_thread(g, p);
 293                         if (who != current->uid)
 294                                 free_uid(user);         /* For find_user() */
 295                         break;
 296         }
 297 out_unlock:
 298         read_unlock(&tasklist_lock);
 299 out:
 300         return error;
 301 }
 302
 303 /*
 304  * Ugh. To avoid negative return values, "getpriority()" will
 305  * not return the normal nice-value, but a negated value that
 306  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 307  * to stay compatible.
 308  */
 309 asmlinkage long sys_getpriority(int which, int who)
 310 {
 311         struct task_struct *g, *p;
 312         struct user_struct *user;
 313         long niceval, retval = -ESRCH;
 314
 315         if (which > 2 || which < 0)
 316                 return -EINVAL;
 317
 318         read_lock(&tasklist_lock);
 319         switch (which) {
 320                 case PRIO_PROCESS:
 321                         if (!who)
 322                                 who = current->pid;
 323                         p = find_task_by_pid(who);
 324                         if (p) {
 325                                 niceval = 20 - task_nice(p);
 326                                 if (niceval > retval)
 327                                         retval = niceval;
 328                         }
 329                         break;
 330                 case PRIO_PGRP:
 331                         if (!who)
 332                                 who = process_group(current);
 333                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 334                                 niceval = 20 - task_nice(p);
 335                                 if (niceval > retval)
 336                                         retval = niceval;
 337                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 338                         break;
 339                 case PRIO_USER:
 340                         user = current->user;
 341                         if (!who)
 342                                 who = current->uid;
 343                         else
 344                                 if ((who != current->uid) && !(user = find_user(who)))
 345                                         goto out_unlock;        /* No processes for this user */
 346
 347                         do_each_thread(g, p)
 348                                 if (p->uid == who) {
 349                                         niceval = 20 - task_nice(p);
 350                                         if (niceval > retval)
 351                                                 retval = niceval;
 352                                 }
 353                         while_each_thread(g, p);
 354                         if (who != current->uid)
 355                                 free_uid(user);         /* for find_user() */
 356                         break;
 357         }
 358 out_unlock:
 359         read_unlock(&tasklist_lock);
 360
 361         return retval;
 362 }
 363
 364
 365 /*
 366  * Reboot system call: for obvious reasons only root may call it,
 367  * and even root needs to set up some magic numbers in the registers
 368  * so that some mistake won't make this reboot the whole machine.
 369  * You can also set the meaning of the ctrl-alt-del-key here.
 370  *
 371  * reboot doesn't sync: do that yourself before calling this.
 372  */
 373 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 374 {
 375         char buffer[256];
 376
 377         /* We only trust the superuser with rebooting the system. */
 378         if (!capable(CAP_SYS_BOOT))
 379                 return -EPERM;
 380
 381         /* For safety, we require "magic" arguments. */
 382         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 383             (magic2 != LINUX_REBOOT_MAGIC2 &&
 384                         magic2 != LINUX_REBOOT_MAGIC2A &&
 385                         magic2 != LINUX_REBOOT_MAGIC2B &&
 386                         magic2 != LINUX_REBOOT_MAGIC2C))
 387                 return -EINVAL;
 388
 389         lock_kernel();
 390         switch (cmd) {
 391         case LINUX_REBOOT_CMD_RESTART:
 392                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 393                 system_state = SYSTEM_RESTART;
 394                 device_suspend(PMSG_FREEZE);
 395                 device_shutdown();
 396                 printk(KERN_EMERG "Restarting system.\n");
 397                 machine_restart(NULL);
 398                 break;
 399
 400         case LINUX_REBOOT_CMD_CAD_ON:
 401                 C_A_D = 1;
 402                 break;
 403
 404         case LINUX_REBOOT_CMD_CAD_OFF:
 405                 C_A_D = 0;
 406                 break;
 407
 408         case LINUX_REBOOT_CMD_HALT:
 409                 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
 410                 system_state = SYSTEM_HALT;
 411                 device_suspend(PMSG_SUSPEND);
 412                 device_shutdown();
 413                 printk(KERN_EMERG "System halted.\n");
 414                 machine_halt();
 415                 unlock_kernel();
 416                 do_exit(0);
 417                 break;
 418
 419         case LINUX_REBOOT_CMD_POWER_OFF:
 420                 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
 421                 system_state = SYSTEM_POWER_OFF;
 422                 device_suspend(PMSG_SUSPEND);
 423                 device_shutdown();
 424                 printk(KERN_EMERG "Power down.\n");
 425                 machine_power_off();
 426                 unlock_kernel();
 427                 do_exit(0);
 428                 break;
 429
 430         case LINUX_REBOOT_CMD_RESTART2:
 431                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 432                         unlock_kernel();
 433                         return -EFAULT;
 434                 }
 435                 buffer[sizeof(buffer) - 1] = '\0';
 436
 437                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
 438                 system_state = SYSTEM_RESTART;
 439                 device_suspend(PMSG_FREEZE);
 440                 device_shutdown();
 441                 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
 442                 machine_restart(buffer);
 443                 break;
 444
 445 #ifdef CONFIG_KEXEC
 446         case LINUX_REBOOT_CMD_KEXEC:
 447         {
 448                 struct kimage *image;
 449                 image = xchg(&kexec_image, 0);
 450                 if (!image) {
 451                         unlock_kernel();
 452                         return -EINVAL;
 453                 }
 454                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 455                 system_state = SYSTEM_RESTART;
 456                 device_suspend(PMSG_FREEZE);
 457                 device_shutdown();
 458                 printk(KERN_EMERG "Starting new kernel\n");
 459                 machine_shutdown();
 460                 machine_kexec(image);
 461                 break;
 462         }
 463 #endif
 464 #ifdef CONFIG_SOFTWARE_SUSPEND
 465         case LINUX_REBOOT_CMD_SW_SUSPEND:
 466                 {
 467                         int ret = software_suspend();
 468                         unlock_kernel();
 469                         return ret;
 470                 }
 471 #endif
 472
 473         default:
 474                 unlock_kernel();
 475                 return -EINVAL;
 476         }
 477         unlock_kernel();
 478         return 0;
 479 }
 480
 481 static void deferred_cad(void *dummy)
 482 {
 483         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 484         machine_restart(NULL);
 485 }
 486
 487 /*
 488  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 489  * As it's called within an interrupt, it may NOT sync: the only choice
 490  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 491  */
 492 void ctrl_alt_del(void)
 493 {
 494         static DECLARE_WORK(cad_work, deferred_cad, NULL);
 495
 496         if (C_A_D)
 497                 schedule_work(&cad_work);
 498         else
 499                 kill_proc(cad_pid, SIGINT, 1);
 500 }
 501
 502
 503 /*
 504  * Unprivileged users may change the real gid to the effective gid
 505  * or vice versa.  (BSD-style)
 506  *
 507  * If you set the real gid at all, or set the effective gid to a value not
 508  * equal to the real gid, then the saved gid is set to the new effective gid.
 509  *
 510  * This makes it possible for a setgid program to completely drop its
 511  * privileges, which is often a useful assertion to make when you are doing
 512  * a security audit over a program.
 513  *
 514  * The general idea is that a program which uses just setregid() will be
 515  * 100% compatible with BSD.  A program which uses just setgid() will be
 516  * 100% compatible with POSIX with saved IDs.
 517  *
 518  * SMP: There are not races, the GIDs are checked only by filesystem
 519  *      operations (as far as semantic preservation is concerned).
 520  */
 521 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 522 {
 523         int old_rgid = current->gid;
 524         int old_egid = current->egid;
 525         int new_rgid = old_rgid;
 526         int new_egid = old_egid;
 527         int retval;
 528
 529         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 530         if (retval)
 531                 return retval;
 532
 533         if (rgid != (gid_t) -1) {
 534                 if ((old_rgid == rgid) ||
 535                     (current->egid==rgid) ||
 536                     capable(CAP_SETGID))
 537                         new_rgid = rgid;
 538                 else
 539                         return -EPERM;
 540         }
 541         if (egid != (gid_t) -1) {
 542                 if ((old_rgid == egid) ||
 543                     (current->egid == egid) ||
 544                     (current->sgid == egid) ||
 545                     capable(CAP_SETGID))
 546                         new_egid = egid;
 547                 else {
 548                         return -EPERM;
 549                 }
 550         }
 551         if (new_egid != old_egid)
 552         {
 553                 current->mm->dumpable = suid_dumpable;
 554                 smp_wmb();
 555         }
 556         if (rgid != (gid_t) -1 ||
 557             (egid != (gid_t) -1 && egid != old_rgid))
 558                 current->sgid = new_egid;
 559         current->fsgid = new_egid;
 560         current->egid = new_egid;
 561         current->gid = new_rgid;
 562         key_fsgid_changed(current);
 563         return 0;
 564 }
 565
 566 /*
 567  * setgid() is implemented like SysV w/ SAVED_IDS
 568  *
 569  * SMP: Same implicit races as above.
 570  */
 571 asmlinkage long sys_setgid(gid_t gid)
 572 {
 573         int old_egid = current->egid;
 574         int retval;
 575
 576         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 577         if (retval)
 578                 return retval;
 579
 580         if (capable(CAP_SETGID))
 581         {
 582                 if(old_egid != gid)
 583                 {
 584                         current->mm->dumpable = suid_dumpable;
 585                         smp_wmb();
 586                 }
 587                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 588         }
 589         else if ((gid == current->gid) || (gid == current->sgid))
 590         {
 591                 if(old_egid != gid)
 592                 {
 593                         current->mm->dumpable = suid_dumpable;
 594                         smp_wmb();
 595                 }
 596                 current->egid = current->fsgid = gid;
 597         }
 598         else
 599                 return -EPERM;
 600
 601         key_fsgid_changed(current);
 602         return 0;
 603 }
 604
 605 static int set_user(uid_t new_ruid, int dumpclear)
 606 {
 607         struct user_struct *new_user;
 608
 609         new_user = alloc_uid(new_ruid);
 610         if (!new_user)
 611                 return -EAGAIN;
 612
 613         if (atomic_read(&new_user->processes) >=
 614                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 615                         new_user != &root_user) {
 616                 free_uid(new_user);
 617                 return -EAGAIN;
 618         }
 619
 620         switch_uid(new_user);
 621
 622         if(dumpclear)
 623         {
 624                 current->mm->dumpable = suid_dumpable;
 625                 smp_wmb();
 626         }
 627         current->uid = new_ruid;
 628         return 0;
 629 }
 630
 631 /*
 632  * Unprivileged users may change the real uid to the effective uid
 633  * or vice versa.  (BSD-style)
 634  *
 635  * If you set the real uid at all, or set the effective uid to a value not
 636  * equal to the real uid, then the saved uid is set to the new effective uid.
 637  *
 638  * This makes it possible for a setuid program to completely drop its
 639  * privileges, which is often a useful assertion to make when you are doing
 640  * a security audit over a program.
 641  *
 642  * The general idea is that a program which uses just setreuid() will be
 643  * 100% compatible with BSD.  A program which uses just setuid() will be
 644  * 100% compatible with POSIX with saved IDs.
 645  */
 646 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 647 {
 648         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 649         int retval;
 650
 651         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 652         if (retval)
 653                 return retval;
 654
 655         new_ruid = old_ruid = current->uid;
 656         new_euid = old_euid = current->euid;
 657         old_suid = current->suid;
 658
 659         if (ruid != (uid_t) -1) {
 660                 new_ruid = ruid;
 661                 if ((old_ruid != ruid) &&
 662                     (current->euid != ruid) &&
 663                     !capable(CAP_SETUID))
 664                         return -EPERM;
 665         }
 666
 667         if (euid != (uid_t) -1) {
 668                 new_euid = euid;
 669                 if ((old_ruid != euid) &&
 670                     (current->euid != euid) &&
 671                     (current->suid != euid) &&
 672                     !capable(CAP_SETUID))
 673                         return -EPERM;
 674         }
 675
 676         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 677                 return -EAGAIN;
 678
 679         if (new_euid != old_euid)
 680         {
 681                 current->mm->dumpable = suid_dumpable;
 682                 smp_wmb();
 683         }
 684         current->fsuid = current->euid = new_euid;
 685         if (ruid != (uid_t) -1 ||
 686             (euid != (uid_t) -1 && euid != old_ruid))
 687                 current->suid = current->euid;
 688         current->fsuid = current->euid;
 689
 690         key_fsuid_changed(current);
 691
 692         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 693 }
 694
 695
 696
 697 /*
 698  * setuid() is implemented like SysV with SAVED_IDS
 699  *
 700  * Note that SAVED_ID's is deficient in that a setuid root program
 701  * like sendmail, for example, cannot set its uid to be a normal
 702  * user and then switch back, because if you're root, setuid() sets
 703  * the saved uid too.  If you don't like this, blame the bright people
 704  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 705  * will allow a root program to temporarily drop privileges and be able to
 706  * regain them by swapping the real and effective uid.
 707  */
 708 asmlinkage long sys_setuid(uid_t uid)
 709 {
 710         int old_euid = current->euid;
 711         int old_ruid, old_suid, new_ruid, new_suid;
 712         int retval;
 713
 714         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 715         if (retval)
 716                 return retval;
 717
 718         old_ruid = new_ruid = current->uid;
 719         old_suid = current->suid;
 720         new_suid = old_suid;
 721
 722         if (capable(CAP_SETUID)) {
 723                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 724                         return -EAGAIN;
 725                 new_suid = uid;
 726         } else if ((uid != current->uid) && (uid != new_suid))
 727                 return -EPERM;
 728
 729         if (old_euid != uid)
 730         {
 731                 current->mm->dumpable = suid_dumpable;
 732                 smp_wmb();
 733         }
 734         current->fsuid = current->euid = uid;
 735         current->suid = new_suid;
 736
 737         key_fsuid_changed(current);
 738
 739         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 740 }
 741
 742
 743 /*
 744  * This function implements a generic ability to update ruid, euid,
 745  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 746  */
 747 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 748 {
 749         int old_ruid = current->uid;
 750         int old_euid = current->euid;
 751         int old_suid = current->suid;
 752         int retval;
 753
 754         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 755         if (retval)
 756                 return retval;
 757
 758         if (!capable(CAP_SETUID)) {
 759                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 760                     (ruid != current->euid) && (ruid != current->suid))
 761                         return -EPERM;
 762                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 763                     (euid != current->euid) && (euid != current->suid))
 764                         return -EPERM;
 765                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 766                     (suid != current->euid) && (suid != current->suid))
 767                         return -EPERM;
 768         }
 769         if (ruid != (uid_t) -1) {
 770                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 771                         return -EAGAIN;
 772         }
 773         if (euid != (uid_t) -1) {
 774                 if (euid != current->euid)
 775                 {
 776                         current->mm->dumpable = suid_dumpable;
 777                         smp_wmb();
 778                 }
 779                 current->euid = euid;
 780         }
 781         current->fsuid = current->euid;
 782         if (suid != (uid_t) -1)
 783                 current->suid = suid;
 784
 785         key_fsuid_changed(current);
 786
 787         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 788 }
 789
 790 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 791 {
 792         int retval;
 793
 794         if (!(retval = put_user(current->uid, ruid)) &&
 795             !(retval = put_user(current->euid, euid)))
 796                 retval = put_user(current->suid, suid);
 797
 798         return retval;
 799 }
 800
 801 /*
 802  * Same as above, but for rgid, egid, sgid.
 803  */
 804 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 805 {
 806         int retval;
 807
 808         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 809         if (retval)
 810                 return retval;
 811
 812         if (!capable(CAP_SETGID)) {
 813                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 814                     (rgid != current->egid) && (rgid != current->sgid))
 815                         return -EPERM;
 816                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 817                     (egid != current->egid) && (egid != current->sgid))
 818                         return -EPERM;
 819                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 820                     (sgid != current->egid) && (sgid != current->sgid))
 821                         return -EPERM;
 822         }
 823         if (egid != (gid_t) -1) {
 824                 if (egid != current->egid)
 825                 {
 826                         current->mm->dumpable = suid_dumpable;
 827                         smp_wmb();
 828                 }
 829                 current->egid = egid;
 830         }
 831         current->fsgid = current->egid;
 832         if (rgid != (gid_t) -1)
 833                 current->gid = rgid;
 834         if (sgid != (gid_t) -1)
 835                 current->sgid = sgid;
 836
 837         key_fsgid_changed(current);
 838         return 0;
 839 }
 840
 841 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 842 {
 843         int retval;
 844
 845         if (!(retval = put_user(current->gid, rgid)) &&
 846             !(retval = put_user(current->egid, egid)))
 847                 retval = put_user(current->sgid, sgid);
 848
 849         return retval;
 850 }
 851
 852
 853 /*
 854  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 855  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 856  * whatever uid it wants to). It normally shadows "euid", except when
 857  * explicitly set by setfsuid() or for access..
 858  */
 859 asmlinkage long sys_setfsuid(uid_t uid)
 860 {
 861         int old_fsuid;
 862
 863         old_fsuid = current->fsuid;
 864         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 865                 return old_fsuid;
 866
 867         if (uid == current->uid || uid == current->euid ||
 868             uid == current->suid || uid == current->fsuid ||
 869             capable(CAP_SETUID))
 870         {
 871                 if (uid != old_fsuid)
 872                 {
 873                         current->mm->dumpable = suid_dumpable;
 874                         smp_wmb();
 875                 }
 876                 current->fsuid = uid;
 877         }
 878
 879         key_fsuid_changed(current);
 880
 881         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 882
 883         return old_fsuid;
 884 }
 885
 886 /*
 887  * Samma på svenska..
 888  */
 889 asmlinkage long sys_setfsgid(gid_t gid)
 890 {
 891         int old_fsgid;
 892
 893         old_fsgid = current->fsgid;
 894         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 895                 return old_fsgid;
 896
 897         if (gid == current->gid || gid == current->egid ||
 898             gid == current->sgid || gid == current->fsgid ||
 899             capable(CAP_SETGID))
 900         {
 901                 if (gid != old_fsgid)
 902                 {
 903                         current->mm->dumpable = suid_dumpable;
 904                         smp_wmb();
 905                 }
 906                 current->fsgid = gid;
 907                 key_fsgid_changed(current);
 908         }
 909         return old_fsgid;
 910 }
 911
 912 asmlinkage long sys_times(struct tms __user * tbuf)
 913 {
 914         /*
 915          *      In the SMP world we might just be unlucky and have one of
 916          *      the times increment as we use it. Since the value is an
 917          *      atomically safe type this is just fine. Conceptually its
 918          *      as if the syscall took an instant longer to occur.
 919          */
 920         if (tbuf) {
 921                 struct tms tmp;
 922                 cputime_t utime, stime, cutime, cstime;
 923
 924 #ifdef CONFIG_SMP
 925                 if (thread_group_empty(current)) {
 926                         /*
 927                          * Single thread case without the use of any locks.
 928                          *
 929                          * We may race with release_task if two threads are
 930                          * executing. However, release task first adds up the
 931                          * counters (__exit_signal) before  removing the task
 932                          * from the process tasklist (__unhash_process).
 933                          * __exit_signal also acquires and releases the
 934                          * siglock which results in the proper memory ordering
 935                          * so that the list modifications are always visible
 936                          * after the counters have been updated.
 937                          *
 938                          * If the counters have been updated by the second thread
 939                          * but the thread has not yet been removed from the list
 940                          * then the other branch will be executing which will
 941                          * block on tasklist_lock until the exit handling of the
 942                          * other task is finished.
 943                          *
 944                          * This also implies that the sighand->siglock cannot
 945                          * be held by another processor. So we can also
 946                          * skip acquiring that lock.
 947                          */
 948                         utime = cputime_add(current->signal->utime, current->utime);
 949                         stime = cputime_add(current->signal->utime, current->stime);
 950                         cutime = current->signal->cutime;
 951                         cstime = current->signal->cstime;
 952                 } else
 953 #endif
 954                 {
 955
 956                         /* Process with multiple threads */
 957                         struct task_struct *tsk = current;
 958                         struct task_struct *t;
 959
 960                         read_lock(&tasklist_lock);
 961                         utime = tsk->signal->utime;
 962                         stime = tsk->signal->stime;
 963                         t = tsk;
 964                         do {
 965                                 utime = cputime_add(utime, t->utime);
 966                                 stime = cputime_add(stime, t->stime);
 967                                 t = next_thread(t);
 968                         } while (t != tsk);
 969
 970                         /*
 971                          * While we have tasklist_lock read-locked, no dying thread
 972                          * can be updating current->signal->[us]time.  Instead,
 973                          * we got their counts included in the live thread loop.
 974                          * However, another thread can come in right now and
 975                          * do a wait call that updates current->signal->c[us]time.
 976                          * To make sure we always see that pair updated atomically,
 977                          * we take the siglock around fetching them.
 978                          */
 979                         spin_lock_irq(&tsk->sighand->siglock);
 980                         cutime = tsk->signal->cutime;
 981                         cstime = tsk->signal->cstime;
 982                         spin_unlock_irq(&tsk->sighand->siglock);
 983                         read_unlock(&tasklist_lock);
 984                 }
 985                 tmp.tms_utime = cputime_to_clock_t(utime);
 986                 tmp.tms_stime = cputime_to_clock_t(stime);
 987                 tmp.tms_cutime = cputime_to_clock_t(cutime);
 988                 tmp.tms_cstime = cputime_to_clock_t(cstime);
 989                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 990                         return -EFAULT;
 991         }
 992         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 993 }
 994
 995 /*
 996  * This needs some heavy checking ...
 997  * I just haven't the stomach for it. I also don't fully
 998  * understand sessions/pgrp etc. Let somebody who does explain it.
 999  *
1000  * OK, I think I have the protection semantics right.... this is really
1001  * only important on a multi-user system anyway, to make sure one user
1002  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1003  *
1004  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1005  * LBT 04.03.94
1006  */
1007
1008 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1009 {
1010         struct task_struct *p;
1011         int err = -EINVAL;
1012
1013         if (!pid)
1014                 pid = current->pid;
1015         if (!pgid)
1016                 pgid = pid;
1017         if (pgid < 0)
1018                 return -EINVAL;
1019
1020         /* From this point forward we keep holding onto the tasklist lock
1021          * so that our parent does not change from under us. -DaveM
1022          */
1023         write_lock_irq(&tasklist_lock);
1024
1025         err = -ESRCH;
1026         p = find_task_by_pid(pid);
1027         if (!p)
1028                 goto out;
1029
1030         err = -EINVAL;
1031         if (!thread_group_leader(p))
1032                 goto out;
1033
1034         if (p->parent == current || p->real_parent == current) {
1035                 err = -EPERM;
1036                 if (p->signal->session != current->signal->session)
1037                         goto out;
1038                 err = -EACCES;
1039                 if (p->did_exec)
1040                         goto out;
1041         } else {
1042                 err = -ESRCH;
1043                 if (p != current)
1044                         goto out;
1045         }
1046
1047         err = -EPERM;
1048         if (p->signal->leader)
1049                 goto out;
1050
1051         if (pgid != pid) {
1052                 struct task_struct *p;
1053
1054                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1055                         if (p->signal->session == current->signal->session)
1056                                 goto ok_pgid;
1057                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1058                 goto out;
1059         }
1060
1061 ok_pgid:
1062         err = security_task_setpgid(p, pgid);
1063         if (err)
1064                 goto out;
1065
1066         if (process_group(p) != pgid) {
1067                 detach_pid(p, PIDTYPE_PGID);
1068                 p->signal->pgrp = pgid;
1069                 attach_pid(p, PIDTYPE_PGID, pgid);
1070         }
1071
1072         err = 0;
1073 out:
1074         /* All paths lead to here, thus we are safe. -DaveM */
1075         write_unlock_irq(&tasklist_lock);
1076         return err;
1077 }
1078
1079 asmlinkage long sys_getpgid(pid_t pid)
1080 {
1081         if (!pid) {
1082                 return process_group(current);
1083         } else {
1084                 int retval;
1085                 struct task_struct *p;
1086
1087                 read_lock(&tasklist_lock);
1088                 p = find_task_by_pid(pid);
1089
1090                 retval = -ESRCH;
1091                 if (p) {
1092                         retval = security_task_getpgid(p);
1093                         if (!retval)
1094                                 retval = process_group(p);
1095                 }
1096                 read_unlock(&tasklist_lock);
1097                 return retval;
1098         }
1099 }
1100
1101 #ifdef __ARCH_WANT_SYS_GETPGRP
1102
1103 asmlinkage long sys_getpgrp(void)
1104 {
1105         /* SMP - assuming writes are word atomic this is fine */
1106         return process_group(current);
1107 }
1108
1109 #endif
1110
1111 asmlinkage long sys_getsid(pid_t pid)
1112 {
1113         if (!pid) {
1114                 return current->signal->session;
1115         } else {
1116                 int retval;
1117                 struct task_struct *p;
1118
1119                 read_lock(&tasklist_lock);
1120                 p = find_task_by_pid(pid);
1121
1122                 retval = -ESRCH;
1123                 if(p) {
1124                         retval = security_task_getsid(p);
1125                         if (!retval)
1126                                 retval = p->signal->session;
1127                 }
1128                 read_unlock(&tasklist_lock);
1129                 return retval;
1130         }
1131 }
1132
1133 asmlinkage long sys_setsid(void)
1134 {
1135         struct pid *pid;
1136         int err = -EPERM;
1137
1138         if (!thread_group_leader(current))
1139                 return -EINVAL;
1140
1141         down(&tty_sem);
1142         write_lock_irq(&tasklist_lock);
1143
1144         pid = find_pid(PIDTYPE_PGID, current->pid);
1145         if (pid)
1146                 goto out;
1147
1148         current->signal->leader = 1;
1149         __set_special_pids(current->pid, current->pid);
1150         current->signal->tty = NULL;
1151         current->signal->tty_old_pgrp = 0;
1152         err = process_group(current);
1153 out:
1154         write_unlock_irq(&tasklist_lock);
1155         up(&tty_sem);
1156         return err;
1157 }
1158
1159 /*
1160  * Supplementary group IDs
1161  */
1162
1163 /* init to 2 - one for init_task, one to ensure it is never freed */
1164 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1165
1166 struct group_info *groups_alloc(int gidsetsize)
1167 {
1168         struct group_info *group_info;
1169         int nblocks;
1170         int i;
1171
1172         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1173         /* Make sure we always allocate at least one indirect block pointer */
1174         nblocks = nblocks ? : 1;
1175         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1176         if (!group_info)
1177                 return NULL;
1178         group_info->ngroups = gidsetsize;
1179         group_info->nblocks = nblocks;
1180         atomic_set(&group_info->usage, 1);
1181
1182         if (gidsetsize <= NGROUPS_SMALL) {
1183                 group_info->blocks[0] = group_info->small_block;
1184         } else {
1185                 for (i = 0; i < nblocks; i++) {
1186                         gid_t *b;
1187                         b = (void *)__get_free_page(GFP_USER);
1188                         if (!b)
1189                                 goto out_undo_partial_alloc;
1190                         group_info->blocks[i] = b;
1191                 }
1192         }
1193         return group_info;
1194
1195 out_undo_partial_alloc:
1196         while (--i >= 0) {
1197                 free_page((unsigned long)group_info->blocks[i]);
1198         }
1199         kfree(group_info);
1200         return NULL;
1201 }
1202
1203 EXPORT_SYMBOL(groups_alloc);
1204
1205 void groups_free(struct group_info *group_info)
1206 {
1207         if (group_info->blocks[0] != group_info->small_block) {
1208                 int i;
1209                 for (i = 0; i < group_info->nblocks; i++)
1210                         free_page((unsigned long)group_info->blocks[i]);
1211         }
1212         kfree(group_info);
1213 }
1214
1215 EXPORT_SYMBOL(groups_free);
1216
1217 /* export the group_info to a user-space array */
1218 static int groups_to_user(gid_t __user *grouplist,
1219     struct group_info *group_info)
1220 {
1221         int i;
1222         int count = group_info->ngroups;
1223
1224         for (i = 0; i < group_info->nblocks; i++) {
1225                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1226                 int off = i * NGROUPS_PER_BLOCK;
1227                 int len = cp_count * sizeof(*grouplist);
1228
1229                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1230                         return -EFAULT;
1231
1232                 count -= cp_count;
1233         }
1234         return 0;
1235 }
1236
1237 /* fill a group_info from a user-space array - it must be allocated already */
1238 static int groups_from_user(struct group_info *group_info,
1239     gid_t __user *grouplist)
1240  {
1241         int i;
1242         int count = group_info->ngroups;
1243
1244         for (i = 0; i < group_info->nblocks; i++) {
1245                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1246                 int off = i * NGROUPS_PER_BLOCK;
1247                 int len = cp_count * sizeof(*grouplist);
1248
1249                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1250                         return -EFAULT;
1251
1252                 count -= cp_count;
1253         }
1254         return 0;
1255 }
1256
1257 /* a simple Shell sort */
1258 static void groups_sort(struct group_info *group_info)
1259 {
1260         int base, max, stride;
1261         int gidsetsize = group_info->ngroups;
1262
1263         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1264                 ; /* nothing */
1265         stride /= 3;
1266
1267         while (stride) {
1268                 max = gidsetsize - stride;
1269                 for (base = 0; base < max; base++) {
1270                         int left = base;
1271                         int right = left + stride;
1272                         gid_t tmp = GROUP_AT(group_info, right);
1273
1274                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1275                                 GROUP_AT(group_info, right) =
1276                                     GROUP_AT(group_info, left);
1277                                 right = left;
1278                                 left -= stride;
1279                         }
1280                         GROUP_AT(group_info, right) = tmp;
1281                 }
1282                 stride /= 3;
1283         }
1284 }
1285
1286 /* a simple bsearch */
1287 int groups_search(struct group_info *group_info, gid_t grp)
1288 {
1289         int left, right;
1290
1291         if (!group_info)
1292                 return 0;
1293
1294         left = 0;
1295         right = group_info->ngroups;
1296         while (left < right) {
1297                 int mid = (left+right)/2;
1298                 int cmp = grp - GROUP_AT(group_info, mid);
1299                 if (cmp > 0)
1300                         left = mid + 1;
1301                 else if (cmp < 0)
1302                         right = mid;
1303                 else
1304                         return 1;
1305         }
1306         return 0;
1307 }
1308
1309 /* validate and set current->group_info */
1310 int set_current_groups(struct group_info *group_info)
1311 {
1312         int retval;
1313         struct group_info *old_info;
1314
1315         retval = security_task_setgroups(group_info);
1316         if (retval)
1317                 return retval;
1318
1319         groups_sort(group_info);
1320         get_group_info(group_info);
1321
1322         task_lock(current);
1323         old_info = current->group_info;
1324         current->group_info = group_info;
1325         task_unlock(current);
1326
1327         put_group_info(old_info);
1328
1329         return 0;
1330 }
1331
1332 EXPORT_SYMBOL(set_current_groups);
1333
1334 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1335 {
1336         int i = 0;
1337
1338         /*
1339          *      SMP: Nobody else can change our grouplist. Thus we are
1340          *      safe.
1341          */
1342
1343         if (gidsetsize < 0)
1344                 return -EINVAL;
1345
1346         /* no need to grab task_lock here; it cannot change */
1347         get_group_info(current->group_info);
1348         i = current->group_info->ngroups;
1349         if (gidsetsize) {
1350                 if (i > gidsetsize) {
1351                         i = -EINVAL;
1352                         goto out;
1353                 }
1354                 if (groups_to_user(grouplist, current->group_info)) {
1355                         i = -EFAULT;
1356                         goto out;
1357                 }
1358         }
1359 out:
1360         put_group_info(current->group_info);
1361         return i;
1362 }
1363
1364 /*
1365  *      SMP: Our groups are copy-on-write. We can set them safely
1366  *      without another task interfering.
1367  */
1368
1369 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1370 {
1371         struct group_info *group_info;
1372         int retval;
1373
1374         if (!capable(CAP_SETGID))
1375                 return -EPERM;
1376         if ((unsigned)gidsetsize > NGROUPS_MAX)
1377                 return -EINVAL;
1378
1379         group_info = groups_alloc(gidsetsize);
1380         if (!group_info)
1381                 return -ENOMEM;
1382         retval = groups_from_user(group_info, grouplist);
1383         if (retval) {
1384                 put_group_info(group_info);
1385                 return retval;
1386         }
1387
1388         retval = set_current_groups(group_info);
1389         put_group_info(group_info);
1390
1391         return retval;
1392 }
1393
1394 /*
1395  * Check whether we're fsgid/egid or in the supplemental group..
1396  */
1397 int in_group_p(gid_t grp)
1398 {
1399         int retval = 1;
1400         if (grp != current->fsgid) {
1401                 get_group_info(current->group_info);
1402                 retval = groups_search(current->group_info, grp);
1403                 put_group_info(current->group_info);
1404         }
1405         return retval;
1406 }
1407
1408 EXPORT_SYMBOL(in_group_p);
1409
1410 int in_egroup_p(gid_t grp)
1411 {
1412         int retval = 1;
1413         if (grp != current->egid) {
1414                 get_group_info(current->group_info);
1415                 retval = groups_search(current->group_info, grp);
1416                 put_group_info(current->group_info);
1417         }
1418         return retval;
1419 }
1420
1421 EXPORT_SYMBOL(in_egroup_p);
1422
1423 DECLARE_RWSEM(uts_sem);
1424
1425 EXPORT_SYMBOL(uts_sem);
1426
1427 asmlinkage long sys_newuname(struct new_utsname __user * name)
1428 {
1429         int errno = 0;
1430
1431         down_read(&uts_sem);
1432         if (copy_to_user(name,&system_utsname,sizeof *name))
1433                 errno = -EFAULT;
1434         up_read(&uts_sem);
1435         return errno;
1436 }
1437
1438 asmlinkage long sys_sethostname(char __user *name, int len)
1439 {
1440         int errno;
1441         char tmp[__NEW_UTS_LEN];
1442
1443         if (!capable(CAP_SYS_ADMIN))
1444                 return -EPERM;
1445         if (len < 0 || len > __NEW_UTS_LEN)
1446                 return -EINVAL;
1447         down_write(&uts_sem);
1448         errno = -EFAULT;
1449         if (!copy_from_user(tmp, name, len)) {
1450                 memcpy(system_utsname.nodename, tmp, len);
1451                 system_utsname.nodename[len] = 0;
1452                 errno = 0;
1453         }
1454         up_write(&uts_sem);
1455         return errno;
1456 }
1457
1458 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1459
1460 asmlinkage long sys_gethostname(char __user *name, int len)
1461 {
1462         int i, errno;
1463
1464         if (len < 0)
1465                 return -EINVAL;
1466         down_read(&uts_sem);
1467         i = 1 + strlen(system_utsname.nodename);
1468         if (i > len)
1469                 i = len;
1470         errno = 0;
1471         if (copy_to_user(name, system_utsname.nodename, i))
1472                 errno = -EFAULT;
1473         up_read(&uts_sem);
1474         return errno;
1475 }
1476
1477 #endif
1478
1479 /*
1480  * Only setdomainname; getdomainname can be implemented by calling
1481  * uname()
1482  */
1483 asmlinkage long sys_setdomainname(char __user *name, int len)
1484 {
1485         int errno;
1486         char tmp[__NEW_UTS_LEN];
1487
1488         if (!capable(CAP_SYS_ADMIN))
1489                 return -EPERM;
1490         if (len < 0 || len > __NEW_UTS_LEN)
1491                 return -EINVAL;
1492
1493         down_write(&uts_sem);
1494         errno = -EFAULT;
1495         if (!copy_from_user(tmp, name, len)) {
1496                 memcpy(system_utsname.domainname, tmp, len);
1497                 system_utsname.domainname[len] = 0;
1498                 errno = 0;
1499         }
1500         up_write(&uts_sem);
1501         return errno;
1502 }
1503
1504 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1505 {
1506         if (resource >= RLIM_NLIMITS)
1507                 return -EINVAL;
1508         else {
1509                 struct rlimit value;
1510                 task_lock(current->group_leader);
1511                 value = current->signal->rlim[resource];
1512                 task_unlock(current->group_leader);
1513                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1514         }
1515 }
1516
1517 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1518
1519 /*
1520  *      Back compatibility for getrlimit. Needed for some apps.
1521  */
1522
1523 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1524 {
1525         struct rlimit x;
1526         if (resource >= RLIM_NLIMITS)
1527                 return -EINVAL;
1528
1529         task_lock(current->group_leader);
1530         x = current->signal->rlim[resource];
1531         task_unlock(current->group_leader);
1532         if(x.rlim_cur > 0x7FFFFFFF)
1533                 x.rlim_cur = 0x7FFFFFFF;
1534         if(x.rlim_max > 0x7FFFFFFF)
1535                 x.rlim_max = 0x7FFFFFFF;
1536         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1537 }
1538
1539 #endif
1540
1541 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1542 {
1543         struct rlimit new_rlim, *old_rlim;
1544         int retval;
1545
1546         if (resource >= RLIM_NLIMITS)
1547                 return -EINVAL;
1548         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1549                 return -EFAULT;
1550        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1551                return -EINVAL;
1552         old_rlim = current->signal->rlim + resource;
1553         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1554             !capable(CAP_SYS_RESOURCE))
1555                 return -EPERM;
1556         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1557                         return -EPERM;
1558
1559         retval = security_task_setrlimit(resource, &new_rlim);
1560         if (retval)
1561                 return retval;
1562
1563         task_lock(current->group_leader);
1564         *old_rlim = new_rlim;
1565         task_unlock(current->group_leader);
1566
1567         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1568             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1569              new_rlim.rlim_cur <= cputime_to_secs(
1570                      current->signal->it_prof_expires))) {
1571                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1572                 read_lock(&tasklist_lock);
1573                 spin_lock_irq(&current->sighand->siglock);
1574                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1575                                       &cputime, NULL);
1576                 spin_unlock_irq(&current->sighand->siglock);
1577                 read_unlock(&tasklist_lock);
1578         }
1579
1580         return 0;
1581 }
1582
1583 /*
1584  * It would make sense to put struct rusage in the task_struct,
1585  * except that would make the task_struct be *really big*.  After
1586  * task_struct gets moved into malloc'ed memory, it would
1587  * make sense to do this.  It will make moving the rest of the information
1588  * a lot simpler!  (Which we're not doing right now because we're not
1589  * measuring them yet).
1590  *
1591  * This expects to be called with tasklist_lock read-locked or better,
1592  * and the siglock not locked.  It may momentarily take the siglock.
1593  *
1594  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1595  * races with threads incrementing their own counters.  But since word
1596  * reads are atomic, we either get new values or old values and we don't
1597  * care which for the sums.  We always take the siglock to protect reading
1598  * the c* fields from p->signal from races with exit.c updating those
1599  * fields when reaping, so a sample either gets all the additions of a
1600  * given child after it's reaped, or none so this sample is before reaping.
1601  */
1602
1603 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1604 {
1605         struct task_struct *t;
1606         unsigned long flags;
1607         cputime_t utime, stime;
1608
1609         memset((char *) r, 0, sizeof *r);
1610
1611         if (unlikely(!p->signal))
1612                 return;
1613
1614         switch (who) {
1615                 case RUSAGE_CHILDREN:
1616                         spin_lock_irqsave(&p->sighand->siglock, flags);
1617                         utime = p->signal->cutime;
1618                         stime = p->signal->cstime;
1619                         r->ru_nvcsw = p->signal->cnvcsw;
1620                         r->ru_nivcsw = p->signal->cnivcsw;
1621                         r->ru_minflt = p->signal->cmin_flt;
1622                         r->ru_majflt = p->signal->cmaj_flt;
1623                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1624                         cputime_to_timeval(utime, &r->ru_utime);
1625                         cputime_to_timeval(stime, &r->ru_stime);
1626                         break;
1627                 case RUSAGE_SELF:
1628                         spin_lock_irqsave(&p->sighand->siglock, flags);
1629                         utime = stime = cputime_zero;
1630                         goto sum_group;
1631                 case RUSAGE_BOTH:
1632                         spin_lock_irqsave(&p->sighand->siglock, flags);
1633                         utime = p->signal->cutime;
1634                         stime = p->signal->cstime;
1635                         r->ru_nvcsw = p->signal->cnvcsw;
1636                         r->ru_nivcsw = p->signal->cnivcsw;
1637                         r->ru_minflt = p->signal->cmin_flt;
1638                         r->ru_majflt = p->signal->cmaj_flt;
1639                 sum_group:
1640                         utime = cputime_add(utime, p->signal->utime);
1641                         stime = cputime_add(stime, p->signal->stime);
1642                         r->ru_nvcsw += p->signal->nvcsw;
1643                         r->ru_nivcsw += p->signal->nivcsw;
1644                         r->ru_minflt += p->signal->min_flt;
1645                         r->ru_majflt += p->signal->maj_flt;
1646                         t = p;
1647                         do {
1648                                 utime = cputime_add(utime, t->utime);
1649                                 stime = cputime_add(stime, t->stime);
1650                                 r->ru_nvcsw += t->nvcsw;
1651                                 r->ru_nivcsw += t->nivcsw;
1652                                 r->ru_minflt += t->min_flt;
1653                                 r->ru_majflt += t->maj_flt;
1654                                 t = next_thread(t);
1655                         } while (t != p);
1656                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1657                         cputime_to_timeval(utime, &r->ru_utime);
1658                         cputime_to_timeval(stime, &r->ru_stime);
1659                         break;
1660                 default:
1661                         BUG();
1662         }
1663 }
1664
1665 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1666 {
1667         struct rusage r;
1668         read_lock(&tasklist_lock);
1669         k_getrusage(p, who, &r);
1670         read_unlock(&tasklist_lock);
1671         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1672 }
1673
1674 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1675 {
1676         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1677                 return -EINVAL;
1678         return getrusage(current, who, ru);
1679 }
1680
1681 asmlinkage long sys_umask(int mask)
1682 {
1683         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1684         return mask;
1685 }
1686
1687 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1688                           unsigned long arg4, unsigned long arg5)
1689 {
1690         long error;
1691         int sig;
1692
1693         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1694         if (error)
1695                 return error;
1696
1697         switch (option) {
1698                 case PR_SET_PDEATHSIG:
1699                         sig = arg2;
1700                         if (!valid_signal(sig)) {
1701                                 error = -EINVAL;
1702                                 break;
1703                         }
1704                         current->pdeath_signal = sig;
1705                         break;
1706                 case PR_GET_PDEATHSIG:
1707                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1708                         break;
1709                 case PR_GET_DUMPABLE:
1710                         if (current->mm->dumpable)
1711                                 error = 1;
1712                         break;
1713                 case PR_SET_DUMPABLE:
1714                         if (arg2 < 0 || arg2 > 2) {
1715                                 error = -EINVAL;
1716                                 break;
1717                         }
1718                         current->mm->dumpable = arg2;
1719                         break;
1720
1721                 case PR_SET_UNALIGN:
1722                         error = SET_UNALIGN_CTL(current, arg2);
1723                         break;
1724                 case PR_GET_UNALIGN:
1725                         error = GET_UNALIGN_CTL(current, arg2);
1726                         break;
1727                 case PR_SET_FPEMU:
1728                         error = SET_FPEMU_CTL(current, arg2);
1729                         break;
1730                 case PR_GET_FPEMU:
1731                         error = GET_FPEMU_CTL(current, arg2);
1732                         break;
1733                 case PR_SET_FPEXC:
1734                         error = SET_FPEXC_CTL(current, arg2);
1735                         break;
1736                 case PR_GET_FPEXC:
1737                         error = GET_FPEXC_CTL(current, arg2);
1738                         break;
1739                 case PR_GET_TIMING:
1740                         error = PR_TIMING_STATISTICAL;
1741                         break;
1742                 case PR_SET_TIMING:
1743                         if (arg2 == PR_TIMING_STATISTICAL)
1744                                 error = 0;
1745                         else
1746                                 error = -EINVAL;
1747                         break;
1748
1749                 case PR_GET_KEEPCAPS:
1750                         if (current->keep_capabilities)
1751                                 error = 1;
1752                         break;
1753                 case PR_SET_KEEPCAPS:
1754                         if (arg2 != 0 && arg2 != 1) {
1755                                 error = -EINVAL;
1756                                 break;
1757                         }
1758                         current->keep_capabilities = arg2;
1759                         break;
1760                 case PR_SET_NAME: {
1761                         struct task_struct *me = current;
1762                         unsigned char ncomm[sizeof(me->comm)];
1763
1764                         ncomm[sizeof(me->comm)-1] = 0;
1765                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1766                                                 sizeof(me->comm)-1) < 0)
1767                                 return -EFAULT;
1768                         set_task_comm(me, ncomm);
1769                         return 0;
1770                 }
1771                 case PR_GET_NAME: {
1772                         struct task_struct *me = current;
1773                         unsigned char tcomm[sizeof(me->comm)];
1774
1775                         get_task_comm(tcomm, me);
1776                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1777                                 return -EFAULT;
1778                         return 0;
1779                 }
1780                 default:
1781                         error = -EINVAL;
1782                         break;
1783         }
1784         return error;
1785 }