git.oblomov.eu Git - linux-2.6/blob - 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/workqueue.h>
  20 #include <linux/device.h>
  21 #include <linux/key.h>
  22 #include <linux/times.h>
  23 #include <linux/posix-timers.h>
  24 #include <linux/security.h>
  25 #include <linux/dcookies.h>
  26 #include <linux/suspend.h>
  27 #include <linux/tty.h>
  28 #include <linux/signal.h>
  29
  30 #include <linux/compat.h>
  31 #include <linux/syscalls.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/io.h>
  35 #include <asm/unistd.h>
  36
  37 #ifndef SET_UNALIGN_CTL
  38 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  39 #endif
  40 #ifndef GET_UNALIGN_CTL
  41 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  42 #endif
  43 #ifndef SET_FPEMU_CTL
  44 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  45 #endif
  46 #ifndef GET_FPEMU_CTL
  47 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  48 #endif
  49 #ifndef SET_FPEXC_CTL
  50 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  51 #endif
  52 #ifndef GET_FPEXC_CTL
  53 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  54 #endif
  55
  56 /*
  57  * this is where the system-wide overflow UID and GID are defined, for
  58  * architectures that now have 32-bit UID/GID but didn't in the past
  59  */
  60
  61 int overflowuid = DEFAULT_OVERFLOWUID;
  62 int overflowgid = DEFAULT_OVERFLOWGID;
  63
  64 #ifdef CONFIG_UID16
  65 EXPORT_SYMBOL(overflowuid);
  66 EXPORT_SYMBOL(overflowgid);
  67 #endif
  68
  69 /*
  70  * the same as above, but for filesystems which can only store a 16-bit
  71  * UID and GID. as such, this is needed on all architectures
  72  */
  73
  74 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  75 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  76
  77 EXPORT_SYMBOL(fs_overflowuid);
  78 EXPORT_SYMBOL(fs_overflowgid);
  79
  80 /*
  81  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
  82  */
  83
  84 int C_A_D = 1;
  85 int cad_pid = 1;
  86
  87 /*
  88  *      Notifier list for kernel code which wants to be called
  89  *      at shutdown. This is used to stop any idling DMA operations
  90  *      and the like.
  91  */
  92
  93 static struct notifier_block *reboot_notifier_list;
  94 static DEFINE_RWLOCK(notifier_lock);
  95
  96 /**
  97  *      notifier_chain_register - Add notifier to a notifier chain
  98  *      @list: Pointer to root list pointer
  99  *      @n: New entry in notifier chain
 100  *
 101  *      Adds a notifier to a notifier chain.
 102  *
 103  *      Currently always returns zero.
 104  */
 105
 106 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
 107 {
 108         write_lock(&notifier_lock);
 109         while(*list)
 110         {
 111                 if(n->priority > (*list)->priority)
 112                         break;
 113                 list= &((*list)->next);
 114         }
 115         n->next = *list;
 116         *list=n;
 117         write_unlock(&notifier_lock);
 118         return 0;
 119 }
 120
 121 EXPORT_SYMBOL(notifier_chain_register);
 122
 123 /**
 124  *      notifier_chain_unregister - Remove notifier from a notifier chain
 125  *      @nl: Pointer to root list pointer
 126  *      @n: New entry in notifier chain
 127  *
 128  *      Removes a notifier from a notifier chain.
 129  *
 130  *      Returns zero on success, or %-ENOENT on failure.
 131  */
 132
 133 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
 134 {
 135         write_lock(&notifier_lock);
 136         while((*nl)!=NULL)
 137         {
 138                 if((*nl)==n)
 139                 {
 140                         *nl=n->next;
 141                         write_unlock(&notifier_lock);
 142                         return 0;
 143                 }
 144                 nl=&((*nl)->next);
 145         }
 146         write_unlock(&notifier_lock);
 147         return -ENOENT;
 148 }
 149
 150 EXPORT_SYMBOL(notifier_chain_unregister);
 151
 152 /**
 153  *      notifier_call_chain - Call functions in a notifier chain
 154  *      @n: Pointer to root pointer of notifier chain
 155  *      @val: Value passed unmodified to notifier function
 156  *      @v: Pointer passed unmodified to notifier function
 157  *
 158  *      Calls each function in a notifier chain in turn.
 159  *
 160  *      If the return value of the notifier can be and'd
 161  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
 162  *      will return immediately, with the return value of
 163  *      the notifier function which halted execution.
 164  *      Otherwise, the return value is the return value
 165  *      of the last notifier function called.
 166  */
 167
 168 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
 169 {
 170         int ret=NOTIFY_DONE;
 171         struct notifier_block *nb = *n;
 172
 173         while(nb)
 174         {
 175                 ret=nb->notifier_call(nb,val,v);
 176                 if(ret&NOTIFY_STOP_MASK)
 177                 {
 178                         return ret;
 179                 }
 180                 nb=nb->next;
 181         }
 182         return ret;
 183 }
 184
 185 EXPORT_SYMBOL(notifier_call_chain);
 186
 187 /**
 188  *      register_reboot_notifier - Register function to be called at reboot time
 189  *      @nb: Info about notifier function to be called
 190  *
 191  *      Registers a function with the list of functions
 192  *      to be called at reboot time.
 193  *
 194  *      Currently always returns zero, as notifier_chain_register
 195  *      always returns zero.
 196  */
 197
 198 int register_reboot_notifier(struct notifier_block * nb)
 199 {
 200         return notifier_chain_register(&reboot_notifier_list, nb);
 201 }
 202
 203 EXPORT_SYMBOL(register_reboot_notifier);
 204
 205 /**
 206  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
 207  *      @nb: Hook to be unregistered
 208  *
 209  *      Unregisters a previously registered reboot
 210  *      notifier function.
 211  *
 212  *      Returns zero on success, or %-ENOENT on failure.
 213  */
 214
 215 int unregister_reboot_notifier(struct notifier_block * nb)
 216 {
 217         return notifier_chain_unregister(&reboot_notifier_list, nb);
 218 }
 219
 220 EXPORT_SYMBOL(unregister_reboot_notifier);
 221
 222 static int set_one_prio(struct task_struct *p, int niceval, int error)
 223 {
 224         int no_nice;
 225
 226         if (p->uid != current->euid &&
 227                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 228                 error = -EPERM;
 229                 goto out;
 230         }
 231         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 232                 error = -EACCES;
 233                 goto out;
 234         }
 235         no_nice = security_task_setnice(p, niceval);
 236         if (no_nice) {
 237                 error = no_nice;
 238                 goto out;
 239         }
 240         if (error == -ESRCH)
 241                 error = 0;
 242         set_user_nice(p, niceval);
 243 out:
 244         return error;
 245 }
 246
 247 asmlinkage long sys_setpriority(int which, int who, int niceval)
 248 {
 249         struct task_struct *g, *p;
 250         struct user_struct *user;
 251         int error = -EINVAL;
 252
 253         if (which > 2 || which < 0)
 254                 goto out;
 255
 256         /* normalize: avoid signed division (rounding problems) */
 257         error = -ESRCH;
 258         if (niceval < -20)
 259                 niceval = -20;
 260         if (niceval > 19)
 261                 niceval = 19;
 262
 263         read_lock(&tasklist_lock);
 264         switch (which) {
 265                 case PRIO_PROCESS:
 266                         if (!who)
 267                                 who = current->pid;
 268                         p = find_task_by_pid(who);
 269                         if (p)
 270                                 error = set_one_prio(p, niceval, error);
 271                         break;
 272                 case PRIO_PGRP:
 273                         if (!who)
 274                                 who = process_group(current);
 275                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 276                                 error = set_one_prio(p, niceval, error);
 277                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 278                         break;
 279                 case PRIO_USER:
 280                         user = current->user;
 281                         if (!who)
 282                                 who = current->uid;
 283                         else
 284                                 if ((who != current->uid) && !(user = find_user(who)))
 285                                         goto out_unlock;        /* No processes for this user */
 286
 287                         do_each_thread(g, p)
 288                                 if (p->uid == who)
 289                                         error = set_one_prio(p, niceval, error);
 290                         while_each_thread(g, p);
 291                         if (who != current->uid)
 292                                 free_uid(user);         /* For find_user() */
 293                         break;
 294         }
 295 out_unlock:
 296         read_unlock(&tasklist_lock);
 297 out:
 298         return error;
 299 }
 300
 301 /*
 302  * Ugh. To avoid negative return values, "getpriority()" will
 303  * not return the normal nice-value, but a negated value that
 304  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 305  * to stay compatible.
 306  */
 307 asmlinkage long sys_getpriority(int which, int who)
 308 {
 309         struct task_struct *g, *p;
 310         struct user_struct *user;
 311         long niceval, retval = -ESRCH;
 312
 313         if (which > 2 || which < 0)
 314                 return -EINVAL;
 315
 316         read_lock(&tasklist_lock);
 317         switch (which) {
 318                 case PRIO_PROCESS:
 319                         if (!who)
 320                                 who = current->pid;
 321                         p = find_task_by_pid(who);
 322                         if (p) {
 323                                 niceval = 20 - task_nice(p);
 324                                 if (niceval > retval)
 325                                         retval = niceval;
 326                         }
 327                         break;
 328                 case PRIO_PGRP:
 329                         if (!who)
 330                                 who = process_group(current);
 331                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 332                                 niceval = 20 - task_nice(p);
 333                                 if (niceval > retval)
 334                                         retval = niceval;
 335                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 336                         break;
 337                 case PRIO_USER:
 338                         user = current->user;
 339                         if (!who)
 340                                 who = current->uid;
 341                         else
 342                                 if ((who != current->uid) && !(user = find_user(who)))
 343                                         goto out_unlock;        /* No processes for this user */
 344
 345                         do_each_thread(g, p)
 346                                 if (p->uid == who) {
 347                                         niceval = 20 - task_nice(p);
 348                                         if (niceval > retval)
 349                                                 retval = niceval;
 350                                 }
 351                         while_each_thread(g, p);
 352                         if (who != current->uid)
 353                                 free_uid(user);         /* for find_user() */
 354                         break;
 355         }
 356 out_unlock:
 357         read_unlock(&tasklist_lock);
 358
 359         return retval;
 360 }
 361
 362
 363 /*
 364  * Reboot system call: for obvious reasons only root may call it,
 365  * and even root needs to set up some magic numbers in the registers
 366  * so that some mistake won't make this reboot the whole machine.
 367  * You can also set the meaning of the ctrl-alt-del-key here.
 368  *
 369  * reboot doesn't sync: do that yourself before calling this.
 370  */
 371 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 372 {
 373         char buffer[256];
 374
 375         /* We only trust the superuser with rebooting the system. */
 376         if (!capable(CAP_SYS_BOOT))
 377                 return -EPERM;
 378
 379         /* For safety, we require "magic" arguments. */
 380         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 381             (magic2 != LINUX_REBOOT_MAGIC2 &&
 382                         magic2 != LINUX_REBOOT_MAGIC2A &&
 383                         magic2 != LINUX_REBOOT_MAGIC2B &&
 384                         magic2 != LINUX_REBOOT_MAGIC2C))
 385                 return -EINVAL;
 386
 387         lock_kernel();
 388         switch (cmd) {
 389         case LINUX_REBOOT_CMD_RESTART:
 390                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 391                 system_state = SYSTEM_RESTART;
 392                 device_shutdown();
 393                 printk(KERN_EMERG "Restarting system.\n");
 394                 machine_restart(NULL);
 395                 break;
 396
 397         case LINUX_REBOOT_CMD_CAD_ON:
 398                 C_A_D = 1;
 399                 break;
 400
 401         case LINUX_REBOOT_CMD_CAD_OFF:
 402                 C_A_D = 0;
 403                 break;
 404
 405         case LINUX_REBOOT_CMD_HALT:
 406                 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
 407                 system_state = SYSTEM_HALT;
 408                 device_shutdown();
 409                 printk(KERN_EMERG "System halted.\n");
 410                 machine_halt();
 411                 unlock_kernel();
 412                 do_exit(0);
 413                 break;
 414
 415         case LINUX_REBOOT_CMD_POWER_OFF:
 416                 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
 417                 system_state = SYSTEM_POWER_OFF;
 418                 device_shutdown();
 419                 printk(KERN_EMERG "Power down.\n");
 420                 machine_power_off();
 421                 unlock_kernel();
 422                 do_exit(0);
 423                 break;
 424
 425         case LINUX_REBOOT_CMD_RESTART2:
 426                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 427                         unlock_kernel();
 428                         return -EFAULT;
 429                 }
 430                 buffer[sizeof(buffer) - 1] = '\0';
 431
 432                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
 433                 system_state = SYSTEM_RESTART;
 434                 device_shutdown();
 435                 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
 436                 machine_restart(buffer);
 437                 break;
 438
 439 #ifdef CONFIG_SOFTWARE_SUSPEND
 440         case LINUX_REBOOT_CMD_SW_SUSPEND:
 441                 {
 442                         int ret = software_suspend();
 443                         unlock_kernel();
 444                         return ret;
 445                 }
 446 #endif
 447
 448         default:
 449                 unlock_kernel();
 450                 return -EINVAL;
 451         }
 452         unlock_kernel();
 453         return 0;
 454 }
 455
 456 static void deferred_cad(void *dummy)
 457 {
 458         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 459         machine_restart(NULL);
 460 }
 461
 462 /*
 463  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 464  * As it's called within an interrupt, it may NOT sync: the only choice
 465  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 466  */
 467 void ctrl_alt_del(void)
 468 {
 469         static DECLARE_WORK(cad_work, deferred_cad, NULL);
 470
 471         if (C_A_D)
 472                 schedule_work(&cad_work);
 473         else
 474                 kill_proc(cad_pid, SIGINT, 1);
 475 }
 476
 477
 478 /*
 479  * Unprivileged users may change the real gid to the effective gid
 480  * or vice versa.  (BSD-style)
 481  *
 482  * If you set the real gid at all, or set the effective gid to a value not
 483  * equal to the real gid, then the saved gid is set to the new effective gid.
 484  *
 485  * This makes it possible for a setgid program to completely drop its
 486  * privileges, which is often a useful assertion to make when you are doing
 487  * a security audit over a program.
 488  *
 489  * The general idea is that a program which uses just setregid() will be
 490  * 100% compatible with BSD.  A program which uses just setgid() will be
 491  * 100% compatible with POSIX with saved IDs.
 492  *
 493  * SMP: There are not races, the GIDs are checked only by filesystem
 494  *      operations (as far as semantic preservation is concerned).
 495  */
 496 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 497 {
 498         int old_rgid = current->gid;
 499         int old_egid = current->egid;
 500         int new_rgid = old_rgid;
 501         int new_egid = old_egid;
 502         int retval;
 503
 504         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 505         if (retval)
 506                 return retval;
 507
 508         if (rgid != (gid_t) -1) {
 509                 if ((old_rgid == rgid) ||
 510                     (current->egid==rgid) ||
 511                     capable(CAP_SETGID))
 512                         new_rgid = rgid;
 513                 else
 514                         return -EPERM;
 515         }
 516         if (egid != (gid_t) -1) {
 517                 if ((old_rgid == egid) ||
 518                     (current->egid == egid) ||
 519                     (current->sgid == egid) ||
 520                     capable(CAP_SETGID))
 521                         new_egid = egid;
 522                 else {
 523                         return -EPERM;
 524                 }
 525         }
 526         if (new_egid != old_egid)
 527         {
 528                 current->mm->dumpable = suid_dumpable;
 529                 smp_wmb();
 530         }
 531         if (rgid != (gid_t) -1 ||
 532             (egid != (gid_t) -1 && egid != old_rgid))
 533                 current->sgid = new_egid;
 534         current->fsgid = new_egid;
 535         current->egid = new_egid;
 536         current->gid = new_rgid;
 537         key_fsgid_changed(current);
 538         return 0;
 539 }
 540
 541 /*
 542  * setgid() is implemented like SysV w/ SAVED_IDS
 543  *
 544  * SMP: Same implicit races as above.
 545  */
 546 asmlinkage long sys_setgid(gid_t gid)
 547 {
 548         int old_egid = current->egid;
 549         int retval;
 550
 551         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 552         if (retval)
 553                 return retval;
 554
 555         if (capable(CAP_SETGID))
 556         {
 557                 if(old_egid != gid)
 558                 {
 559                         current->mm->dumpable = suid_dumpable;
 560                         smp_wmb();
 561                 }
 562                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 563         }
 564         else if ((gid == current->gid) || (gid == current->sgid))
 565         {
 566                 if(old_egid != gid)
 567                 {
 568                         current->mm->dumpable = suid_dumpable;
 569                         smp_wmb();
 570                 }
 571                 current->egid = current->fsgid = gid;
 572         }
 573         else
 574                 return -EPERM;
 575
 576         key_fsgid_changed(current);
 577         return 0;
 578 }
 579
 580 static int set_user(uid_t new_ruid, int dumpclear)
 581 {
 582         struct user_struct *new_user;
 583
 584         new_user = alloc_uid(new_ruid);
 585         if (!new_user)
 586                 return -EAGAIN;
 587
 588         if (atomic_read(&new_user->processes) >=
 589                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 590                         new_user != &root_user) {
 591                 free_uid(new_user);
 592                 return -EAGAIN;
 593         }
 594
 595         switch_uid(new_user);
 596
 597         if(dumpclear)
 598         {
 599                 current->mm->dumpable = suid_dumpable;
 600                 smp_wmb();
 601         }
 602         current->uid = new_ruid;
 603         return 0;
 604 }
 605
 606 /*
 607  * Unprivileged users may change the real uid to the effective uid
 608  * or vice versa.  (BSD-style)
 609  *
 610  * If you set the real uid at all, or set the effective uid to a value not
 611  * equal to the real uid, then the saved uid is set to the new effective uid.
 612  *
 613  * This makes it possible for a setuid program to completely drop its
 614  * privileges, which is often a useful assertion to make when you are doing
 615  * a security audit over a program.
 616  *
 617  * The general idea is that a program which uses just setreuid() will be
 618  * 100% compatible with BSD.  A program which uses just setuid() will be
 619  * 100% compatible with POSIX with saved IDs.
 620  */
 621 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 622 {
 623         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 624         int retval;
 625
 626         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 627         if (retval)
 628                 return retval;
 629
 630         new_ruid = old_ruid = current->uid;
 631         new_euid = old_euid = current->euid;
 632         old_suid = current->suid;
 633
 634         if (ruid != (uid_t) -1) {
 635                 new_ruid = ruid;
 636                 if ((old_ruid != ruid) &&
 637                     (current->euid != ruid) &&
 638                     !capable(CAP_SETUID))
 639                         return -EPERM;
 640         }
 641
 642         if (euid != (uid_t) -1) {
 643                 new_euid = euid;
 644                 if ((old_ruid != euid) &&
 645                     (current->euid != euid) &&
 646                     (current->suid != euid) &&
 647                     !capable(CAP_SETUID))
 648                         return -EPERM;
 649         }
 650
 651         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 652                 return -EAGAIN;
 653
 654         if (new_euid != old_euid)
 655         {
 656                 current->mm->dumpable = suid_dumpable;
 657                 smp_wmb();
 658         }
 659         current->fsuid = current->euid = new_euid;
 660         if (ruid != (uid_t) -1 ||
 661             (euid != (uid_t) -1 && euid != old_ruid))
 662                 current->suid = current->euid;
 663         current->fsuid = current->euid;
 664
 665         key_fsuid_changed(current);
 666
 667         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 668 }
 669
 670
 671
 672 /*
 673  * setuid() is implemented like SysV with SAVED_IDS
 674  *
 675  * Note that SAVED_ID's is deficient in that a setuid root program
 676  * like sendmail, for example, cannot set its uid to be a normal
 677  * user and then switch back, because if you're root, setuid() sets
 678  * the saved uid too.  If you don't like this, blame the bright people
 679  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 680  * will allow a root program to temporarily drop privileges and be able to
 681  * regain them by swapping the real and effective uid.
 682  */
 683 asmlinkage long sys_setuid(uid_t uid)
 684 {
 685         int old_euid = current->euid;
 686         int old_ruid, old_suid, new_ruid, new_suid;
 687         int retval;
 688
 689         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 690         if (retval)
 691                 return retval;
 692
 693         old_ruid = new_ruid = current->uid;
 694         old_suid = current->suid;
 695         new_suid = old_suid;
 696
 697         if (capable(CAP_SETUID)) {
 698                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 699                         return -EAGAIN;
 700                 new_suid = uid;
 701         } else if ((uid != current->uid) && (uid != new_suid))
 702                 return -EPERM;
 703
 704         if (old_euid != uid)
 705         {
 706                 current->mm->dumpable = suid_dumpable;
 707                 smp_wmb();
 708         }
 709         current->fsuid = current->euid = uid;
 710         current->suid = new_suid;
 711
 712         key_fsuid_changed(current);
 713
 714         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 715 }
 716
 717
 718 /*
 719  * This function implements a generic ability to update ruid, euid,
 720  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 721  */
 722 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 723 {
 724         int old_ruid = current->uid;
 725         int old_euid = current->euid;
 726         int old_suid = current->suid;
 727         int retval;
 728
 729         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 730         if (retval)
 731                 return retval;
 732
 733         if (!capable(CAP_SETUID)) {
 734                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 735                     (ruid != current->euid) && (ruid != current->suid))
 736                         return -EPERM;
 737                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 738                     (euid != current->euid) && (euid != current->suid))
 739                         return -EPERM;
 740                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 741                     (suid != current->euid) && (suid != current->suid))
 742                         return -EPERM;
 743         }
 744         if (ruid != (uid_t) -1) {
 745                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 746                         return -EAGAIN;
 747         }
 748         if (euid != (uid_t) -1) {
 749                 if (euid != current->euid)
 750                 {
 751                         current->mm->dumpable = suid_dumpable;
 752                         smp_wmb();
 753                 }
 754                 current->euid = euid;
 755         }
 756         current->fsuid = current->euid;
 757         if (suid != (uid_t) -1)
 758                 current->suid = suid;
 759
 760         key_fsuid_changed(current);
 761
 762         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 763 }
 764
 765 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 766 {
 767         int retval;
 768
 769         if (!(retval = put_user(current->uid, ruid)) &&
 770             !(retval = put_user(current->euid, euid)))
 771                 retval = put_user(current->suid, suid);
 772
 773         return retval;
 774 }
 775
 776 /*
 777  * Same as above, but for rgid, egid, sgid.
 778  */
 779 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 780 {
 781         int retval;
 782
 783         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 784         if (retval)
 785                 return retval;
 786
 787         if (!capable(CAP_SETGID)) {
 788                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 789                     (rgid != current->egid) && (rgid != current->sgid))
 790                         return -EPERM;
 791                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 792                     (egid != current->egid) && (egid != current->sgid))
 793                         return -EPERM;
 794                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 795                     (sgid != current->egid) && (sgid != current->sgid))
 796                         return -EPERM;
 797         }
 798         if (egid != (gid_t) -1) {
 799                 if (egid != current->egid)
 800                 {
 801                         current->mm->dumpable = suid_dumpable;
 802                         smp_wmb();
 803                 }
 804                 current->egid = egid;
 805         }
 806         current->fsgid = current->egid;
 807         if (rgid != (gid_t) -1)
 808                 current->gid = rgid;
 809         if (sgid != (gid_t) -1)
 810                 current->sgid = sgid;
 811
 812         key_fsgid_changed(current);
 813         return 0;
 814 }
 815
 816 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 817 {
 818         int retval;
 819
 820         if (!(retval = put_user(current->gid, rgid)) &&
 821             !(retval = put_user(current->egid, egid)))
 822                 retval = put_user(current->sgid, sgid);
 823
 824         return retval;
 825 }
 826
 827
 828 /*
 829  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 830  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 831  * whatever uid it wants to). It normally shadows "euid", except when
 832  * explicitly set by setfsuid() or for access..
 833  */
 834 asmlinkage long sys_setfsuid(uid_t uid)
 835 {
 836         int old_fsuid;
 837
 838         old_fsuid = current->fsuid;
 839         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 840                 return old_fsuid;
 841
 842         if (uid == current->uid || uid == current->euid ||
 843             uid == current->suid || uid == current->fsuid ||
 844             capable(CAP_SETUID))
 845         {
 846                 if (uid != old_fsuid)
 847                 {
 848                         current->mm->dumpable = suid_dumpable;
 849                         smp_wmb();
 850                 }
 851                 current->fsuid = uid;
 852         }
 853
 854         key_fsuid_changed(current);
 855
 856         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 857
 858         return old_fsuid;
 859 }
 860
 861 /*
 862  * Samma på svenska..
 863  */
 864 asmlinkage long sys_setfsgid(gid_t gid)
 865 {
 866         int old_fsgid;
 867
 868         old_fsgid = current->fsgid;
 869         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 870                 return old_fsgid;
 871
 872         if (gid == current->gid || gid == current->egid ||
 873             gid == current->sgid || gid == current->fsgid ||
 874             capable(CAP_SETGID))
 875         {
 876                 if (gid != old_fsgid)
 877                 {
 878                         current->mm->dumpable = suid_dumpable;
 879                         smp_wmb();
 880                 }
 881                 current->fsgid = gid;
 882                 key_fsgid_changed(current);
 883         }
 884         return old_fsgid;
 885 }
 886
 887 asmlinkage long sys_times(struct tms __user * tbuf)
 888 {
 889         /*
 890          *      In the SMP world we might just be unlucky and have one of
 891          *      the times increment as we use it. Since the value is an
 892          *      atomically safe type this is just fine. Conceptually its
 893          *      as if the syscall took an instant longer to occur.
 894          */
 895         if (tbuf) {
 896                 struct tms tmp;
 897                 cputime_t utime, stime, cutime, cstime;
 898
 899 #ifdef CONFIG_SMP
 900                 if (thread_group_empty(current)) {
 901                         /*
 902                          * Single thread case without the use of any locks.
 903                          *
 904                          * We may race with release_task if two threads are
 905                          * executing. However, release task first adds up the
 906                          * counters (__exit_signal) before  removing the task
 907                          * from the process tasklist (__unhash_process).
 908                          * __exit_signal also acquires and releases the
 909                          * siglock which results in the proper memory ordering
 910                          * so that the list modifications are always visible
 911                          * after the counters have been updated.
 912                          *
 913                          * If the counters have been updated by the second thread
 914                          * but the thread has not yet been removed from the list
 915                          * then the other branch will be executing which will
 916                          * block on tasklist_lock until the exit handling of the
 917                          * other task is finished.
 918                          *
 919                          * This also implies that the sighand->siglock cannot
 920                          * be held by another processor. So we can also
 921                          * skip acquiring that lock.
 922                          */
 923                         utime = cputime_add(current->signal->utime, current->utime);
 924                         stime = cputime_add(current->signal->utime, current->stime);
 925                         cutime = current->signal->cutime;
 926                         cstime = current->signal->cstime;
 927                 } else
 928 #endif
 929                 {
 930
 931                         /* Process with multiple threads */
 932                         struct task_struct *tsk = current;
 933                         struct task_struct *t;
 934
 935                         read_lock(&tasklist_lock);
 936                         utime = tsk->signal->utime;
 937                         stime = tsk->signal->stime;
 938                         t = tsk;
 939                         do {
 940                                 utime = cputime_add(utime, t->utime);
 941                                 stime = cputime_add(stime, t->stime);
 942                                 t = next_thread(t);
 943                         } while (t != tsk);
 944
 945                         /*
 946                          * While we have tasklist_lock read-locked, no dying thread
 947                          * can be updating current->signal->[us]time.  Instead,
 948                          * we got their counts included in the live thread loop.
 949                          * However, another thread can come in right now and
 950                          * do a wait call that updates current->signal->c[us]time.
 951                          * To make sure we always see that pair updated atomically,
 952                          * we take the siglock around fetching them.
 953                          */
 954                         spin_lock_irq(&tsk->sighand->siglock);
 955                         cutime = tsk->signal->cutime;
 956                         cstime = tsk->signal->cstime;
 957                         spin_unlock_irq(&tsk->sighand->siglock);
 958                         read_unlock(&tasklist_lock);
 959                 }
 960                 tmp.tms_utime = cputime_to_clock_t(utime);
 961                 tmp.tms_stime = cputime_to_clock_t(stime);
 962                 tmp.tms_cutime = cputime_to_clock_t(cutime);
 963                 tmp.tms_cstime = cputime_to_clock_t(cstime);
 964                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 965                         return -EFAULT;
 966         }
 967         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 968 }
 969
 970 /*
 971  * This needs some heavy checking ...
 972  * I just haven't the stomach for it. I also don't fully
 973  * understand sessions/pgrp etc. Let somebody who does explain it.
 974  *
 975  * OK, I think I have the protection semantics right.... this is really
 976  * only important on a multi-user system anyway, to make sure one user
 977  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 978  *
 979  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 980  * LBT 04.03.94
 981  */
 982
 983 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 984 {
 985         struct task_struct *p;
 986         int err = -EINVAL;
 987
 988         if (!pid)
 989                 pid = current->pid;
 990         if (!pgid)
 991                 pgid = pid;
 992         if (pgid < 0)
 993                 return -EINVAL;
 994
 995         /* From this point forward we keep holding onto the tasklist lock
 996          * so that our parent does not change from under us. -DaveM
 997          */
 998         write_lock_irq(&tasklist_lock);
 999
1000         err = -ESRCH;
1001         p = find_task_by_pid(pid);
1002         if (!p)
1003                 goto out;
1004
1005         err = -EINVAL;
1006         if (!thread_group_leader(p))
1007                 goto out;
1008
1009         if (p->parent == current || p->real_parent == current) {
1010                 err = -EPERM;
1011                 if (p->signal->session != current->signal->session)
1012                         goto out;
1013                 err = -EACCES;
1014                 if (p->did_exec)
1015                         goto out;
1016         } else {
1017                 err = -ESRCH;
1018                 if (p != current)
1019                         goto out;
1020         }
1021
1022         err = -EPERM;
1023         if (p->signal->leader)
1024                 goto out;
1025
1026         if (pgid != pid) {
1027                 struct task_struct *p;
1028
1029                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1030                         if (p->signal->session == current->signal->session)
1031                                 goto ok_pgid;
1032                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1033                 goto out;
1034         }
1035
1036 ok_pgid:
1037         err = security_task_setpgid(p, pgid);
1038         if (err)
1039                 goto out;
1040
1041         if (process_group(p) != pgid) {
1042                 detach_pid(p, PIDTYPE_PGID);
1043                 p->signal->pgrp = pgid;
1044                 attach_pid(p, PIDTYPE_PGID, pgid);
1045         }
1046
1047         err = 0;
1048 out:
1049         /* All paths lead to here, thus we are safe. -DaveM */
1050         write_unlock_irq(&tasklist_lock);
1051         return err;
1052 }
1053
1054 asmlinkage long sys_getpgid(pid_t pid)
1055 {
1056         if (!pid) {
1057                 return process_group(current);
1058         } else {
1059                 int retval;
1060                 struct task_struct *p;
1061
1062                 read_lock(&tasklist_lock);
1063                 p = find_task_by_pid(pid);
1064
1065                 retval = -ESRCH;
1066                 if (p) {
1067                         retval = security_task_getpgid(p);
1068                         if (!retval)
1069                                 retval = process_group(p);
1070                 }
1071                 read_unlock(&tasklist_lock);
1072                 return retval;
1073         }
1074 }
1075
1076 #ifdef __ARCH_WANT_SYS_GETPGRP
1077
1078 asmlinkage long sys_getpgrp(void)
1079 {
1080         /* SMP - assuming writes are word atomic this is fine */
1081         return process_group(current);
1082 }
1083
1084 #endif
1085
1086 asmlinkage long sys_getsid(pid_t pid)
1087 {
1088         if (!pid) {
1089                 return current->signal->session;
1090         } else {
1091                 int retval;
1092                 struct task_struct *p;
1093
1094                 read_lock(&tasklist_lock);
1095                 p = find_task_by_pid(pid);
1096
1097                 retval = -ESRCH;
1098                 if(p) {
1099                         retval = security_task_getsid(p);
1100                         if (!retval)
1101                                 retval = p->signal->session;
1102                 }
1103                 read_unlock(&tasklist_lock);
1104                 return retval;
1105         }
1106 }
1107
1108 asmlinkage long sys_setsid(void)
1109 {
1110         struct pid *pid;
1111         int err = -EPERM;
1112
1113         if (!thread_group_leader(current))
1114                 return -EINVAL;
1115
1116         down(&tty_sem);
1117         write_lock_irq(&tasklist_lock);
1118
1119         pid = find_pid(PIDTYPE_PGID, current->pid);
1120         if (pid)
1121                 goto out;
1122
1123         current->signal->leader = 1;
1124         __set_special_pids(current->pid, current->pid);
1125         current->signal->tty = NULL;
1126         current->signal->tty_old_pgrp = 0;
1127         err = process_group(current);
1128 out:
1129         write_unlock_irq(&tasklist_lock);
1130         up(&tty_sem);
1131         return err;
1132 }
1133
1134 /*
1135  * Supplementary group IDs
1136  */
1137
1138 /* init to 2 - one for init_task, one to ensure it is never freed */
1139 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1140
1141 struct group_info *groups_alloc(int gidsetsize)
1142 {
1143         struct group_info *group_info;
1144         int nblocks;
1145         int i;
1146
1147         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1148         /* Make sure we always allocate at least one indirect block pointer */
1149         nblocks = nblocks ? : 1;
1150         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1151         if (!group_info)
1152                 return NULL;
1153         group_info->ngroups = gidsetsize;
1154         group_info->nblocks = nblocks;
1155         atomic_set(&group_info->usage, 1);
1156
1157         if (gidsetsize <= NGROUPS_SMALL) {
1158                 group_info->blocks[0] = group_info->small_block;
1159         } else {
1160                 for (i = 0; i < nblocks; i++) {
1161                         gid_t *b;
1162                         b = (void *)__get_free_page(GFP_USER);
1163                         if (!b)
1164                                 goto out_undo_partial_alloc;
1165                         group_info->blocks[i] = b;
1166                 }
1167         }
1168         return group_info;
1169
1170 out_undo_partial_alloc:
1171         while (--i >= 0) {
1172                 free_page((unsigned long)group_info->blocks[i]);
1173         }
1174         kfree(group_info);
1175         return NULL;
1176 }
1177
1178 EXPORT_SYMBOL(groups_alloc);
1179
1180 void groups_free(struct group_info *group_info)
1181 {
1182         if (group_info->blocks[0] != group_info->small_block) {
1183                 int i;
1184                 for (i = 0; i < group_info->nblocks; i++)
1185                         free_page((unsigned long)group_info->blocks[i]);
1186         }
1187         kfree(group_info);
1188 }
1189
1190 EXPORT_SYMBOL(groups_free);
1191
1192 /* export the group_info to a user-space array */
1193 static int groups_to_user(gid_t __user *grouplist,
1194     struct group_info *group_info)
1195 {
1196         int i;
1197         int count = group_info->ngroups;
1198
1199         for (i = 0; i < group_info->nblocks; i++) {
1200                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1201                 int off = i * NGROUPS_PER_BLOCK;
1202                 int len = cp_count * sizeof(*grouplist);
1203
1204                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1205                         return -EFAULT;
1206
1207                 count -= cp_count;
1208         }
1209         return 0;
1210 }
1211
1212 /* fill a group_info from a user-space array - it must be allocated already */
1213 static int groups_from_user(struct group_info *group_info,
1214     gid_t __user *grouplist)
1215  {
1216         int i;
1217         int count = group_info->ngroups;
1218
1219         for (i = 0; i < group_info->nblocks; i++) {
1220                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1221                 int off = i * NGROUPS_PER_BLOCK;
1222                 int len = cp_count * sizeof(*grouplist);
1223
1224                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1225                         return -EFAULT;
1226
1227                 count -= cp_count;
1228         }
1229         return 0;
1230 }
1231
1232 /* a simple Shell sort */
1233 static void groups_sort(struct group_info *group_info)
1234 {
1235         int base, max, stride;
1236         int gidsetsize = group_info->ngroups;
1237
1238         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1239                 ; /* nothing */
1240         stride /= 3;
1241
1242         while (stride) {
1243                 max = gidsetsize - stride;
1244                 for (base = 0; base < max; base++) {
1245                         int left = base;
1246                         int right = left + stride;
1247                         gid_t tmp = GROUP_AT(group_info, right);
1248
1249                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1250                                 GROUP_AT(group_info, right) =
1251                                     GROUP_AT(group_info, left);
1252                                 right = left;
1253                                 left -= stride;
1254                         }
1255                         GROUP_AT(group_info, right) = tmp;
1256                 }
1257                 stride /= 3;
1258         }
1259 }
1260
1261 /* a simple bsearch */
1262 static int groups_search(struct group_info *group_info, gid_t grp)
1263 {
1264         int left, right;
1265
1266         if (!group_info)
1267                 return 0;
1268
1269         left = 0;
1270         right = group_info->ngroups;
1271         while (left < right) {
1272                 int mid = (left+right)/2;
1273                 int cmp = grp - GROUP_AT(group_info, mid);
1274                 if (cmp > 0)
1275                         left = mid + 1;
1276                 else if (cmp < 0)
1277                         right = mid;
1278                 else
1279                         return 1;
1280         }
1281         return 0;
1282 }
1283
1284 /* validate and set current->group_info */
1285 int set_current_groups(struct group_info *group_info)
1286 {
1287         int retval;
1288         struct group_info *old_info;
1289
1290         retval = security_task_setgroups(group_info);
1291         if (retval)
1292                 return retval;
1293
1294         groups_sort(group_info);
1295         get_group_info(group_info);
1296
1297         task_lock(current);
1298         old_info = current->group_info;
1299         current->group_info = group_info;
1300         task_unlock(current);
1301
1302         put_group_info(old_info);
1303
1304         return 0;
1305 }
1306
1307 EXPORT_SYMBOL(set_current_groups);
1308
1309 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1310 {
1311         int i = 0;
1312
1313         /*
1314          *      SMP: Nobody else can change our grouplist. Thus we are
1315          *      safe.
1316          */
1317
1318         if (gidsetsize < 0)
1319                 return -EINVAL;
1320
1321         /* no need to grab task_lock here; it cannot change */
1322         get_group_info(current->group_info);
1323         i = current->group_info->ngroups;
1324         if (gidsetsize) {
1325                 if (i > gidsetsize) {
1326                         i = -EINVAL;
1327                         goto out;
1328                 }
1329                 if (groups_to_user(grouplist, current->group_info)) {
1330                         i = -EFAULT;
1331                         goto out;
1332                 }
1333         }
1334 out:
1335         put_group_info(current->group_info);
1336         return i;
1337 }
1338
1339 /*
1340  *      SMP: Our groups are copy-on-write. We can set them safely
1341  *      without another task interfering.
1342  */
1343
1344 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1345 {
1346         struct group_info *group_info;
1347         int retval;
1348
1349         if (!capable(CAP_SETGID))
1350                 return -EPERM;
1351         if ((unsigned)gidsetsize > NGROUPS_MAX)
1352                 return -EINVAL;
1353
1354         group_info = groups_alloc(gidsetsize);
1355         if (!group_info)
1356                 return -ENOMEM;
1357         retval = groups_from_user(group_info, grouplist);
1358         if (retval) {
1359                 put_group_info(group_info);
1360                 return retval;
1361         }
1362
1363         retval = set_current_groups(group_info);
1364         put_group_info(group_info);
1365
1366         return retval;
1367 }
1368
1369 /*
1370  * Check whether we're fsgid/egid or in the supplemental group..
1371  */
1372 int in_group_p(gid_t grp)
1373 {
1374         int retval = 1;
1375         if (grp != current->fsgid) {
1376                 get_group_info(current->group_info);
1377                 retval = groups_search(current->group_info, grp);
1378                 put_group_info(current->group_info);
1379         }
1380         return retval;
1381 }
1382
1383 EXPORT_SYMBOL(in_group_p);
1384
1385 int in_egroup_p(gid_t grp)
1386 {
1387         int retval = 1;
1388         if (grp != current->egid) {
1389                 get_group_info(current->group_info);
1390                 retval = groups_search(current->group_info, grp);
1391                 put_group_info(current->group_info);
1392         }
1393         return retval;
1394 }
1395
1396 EXPORT_SYMBOL(in_egroup_p);
1397
1398 DECLARE_RWSEM(uts_sem);
1399
1400 EXPORT_SYMBOL(uts_sem);
1401
1402 asmlinkage long sys_newuname(struct new_utsname __user * name)
1403 {
1404         int errno = 0;
1405
1406         down_read(&uts_sem);
1407         if (copy_to_user(name,&system_utsname,sizeof *name))
1408                 errno = -EFAULT;
1409         up_read(&uts_sem);
1410         return errno;
1411 }
1412
1413 asmlinkage long sys_sethostname(char __user *name, int len)
1414 {
1415         int errno;
1416         char tmp[__NEW_UTS_LEN];
1417
1418         if (!capable(CAP_SYS_ADMIN))
1419                 return -EPERM;
1420         if (len < 0 || len > __NEW_UTS_LEN)
1421                 return -EINVAL;
1422         down_write(&uts_sem);
1423         errno = -EFAULT;
1424         if (!copy_from_user(tmp, name, len)) {
1425                 memcpy(system_utsname.nodename, tmp, len);
1426                 system_utsname.nodename[len] = 0;
1427                 errno = 0;
1428         }
1429         up_write(&uts_sem);
1430         return errno;
1431 }
1432
1433 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1434
1435 asmlinkage long sys_gethostname(char __user *name, int len)
1436 {
1437         int i, errno;
1438
1439         if (len < 0)
1440                 return -EINVAL;
1441         down_read(&uts_sem);
1442         i = 1 + strlen(system_utsname.nodename);
1443         if (i > len)
1444                 i = len;
1445         errno = 0;
1446         if (copy_to_user(name, system_utsname.nodename, i))
1447                 errno = -EFAULT;
1448         up_read(&uts_sem);
1449         return errno;
1450 }
1451
1452 #endif
1453
1454 /*
1455  * Only setdomainname; getdomainname can be implemented by calling
1456  * uname()
1457  */
1458 asmlinkage long sys_setdomainname(char __user *name, int len)
1459 {
1460         int errno;
1461         char tmp[__NEW_UTS_LEN];
1462
1463         if (!capable(CAP_SYS_ADMIN))
1464                 return -EPERM;
1465         if (len < 0 || len > __NEW_UTS_LEN)
1466                 return -EINVAL;
1467
1468         down_write(&uts_sem);
1469         errno = -EFAULT;
1470         if (!copy_from_user(tmp, name, len)) {
1471                 memcpy(system_utsname.domainname, tmp, len);
1472                 system_utsname.domainname[len] = 0;
1473                 errno = 0;
1474         }
1475         up_write(&uts_sem);
1476         return errno;
1477 }
1478
1479 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1480 {
1481         if (resource >= RLIM_NLIMITS)
1482                 return -EINVAL;
1483         else {
1484                 struct rlimit value;
1485                 task_lock(current->group_leader);
1486                 value = current->signal->rlim[resource];
1487                 task_unlock(current->group_leader);
1488                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1489         }
1490 }
1491
1492 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1493
1494 /*
1495  *      Back compatibility for getrlimit. Needed for some apps.
1496  */
1497
1498 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1499 {
1500         struct rlimit x;
1501         if (resource >= RLIM_NLIMITS)
1502                 return -EINVAL;
1503
1504         task_lock(current->group_leader);
1505         x = current->signal->rlim[resource];
1506         task_unlock(current->group_leader);
1507         if(x.rlim_cur > 0x7FFFFFFF)
1508                 x.rlim_cur = 0x7FFFFFFF;
1509         if(x.rlim_max > 0x7FFFFFFF)
1510                 x.rlim_max = 0x7FFFFFFF;
1511         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1512 }
1513
1514 #endif
1515
1516 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1517 {
1518         struct rlimit new_rlim, *old_rlim;
1519         int retval;
1520
1521         if (resource >= RLIM_NLIMITS)
1522                 return -EINVAL;
1523         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1524                 return -EFAULT;
1525        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1526                return -EINVAL;
1527         old_rlim = current->signal->rlim + resource;
1528         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1529             !capable(CAP_SYS_RESOURCE))
1530                 return -EPERM;
1531         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1532                         return -EPERM;
1533
1534         retval = security_task_setrlimit(resource, &new_rlim);
1535         if (retval)
1536                 return retval;
1537
1538         task_lock(current->group_leader);
1539         *old_rlim = new_rlim;
1540         task_unlock(current->group_leader);
1541
1542         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1543             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1544              new_rlim.rlim_cur <= cputime_to_secs(
1545                      current->signal->it_prof_expires))) {
1546                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1547                 read_lock(&tasklist_lock);
1548                 spin_lock_irq(&current->sighand->siglock);
1549                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1550                                       &cputime, NULL);
1551                 spin_unlock_irq(&current->sighand->siglock);
1552                 read_unlock(&tasklist_lock);
1553         }
1554
1555         return 0;
1556 }
1557
1558 /*
1559  * It would make sense to put struct rusage in the task_struct,
1560  * except that would make the task_struct be *really big*.  After
1561  * task_struct gets moved into malloc'ed memory, it would
1562  * make sense to do this.  It will make moving the rest of the information
1563  * a lot simpler!  (Which we're not doing right now because we're not
1564  * measuring them yet).
1565  *
1566  * This expects to be called with tasklist_lock read-locked or better,
1567  * and the siglock not locked.  It may momentarily take the siglock.
1568  *
1569  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1570  * races with threads incrementing their own counters.  But since word
1571  * reads are atomic, we either get new values or old values and we don't
1572  * care which for the sums.  We always take the siglock to protect reading
1573  * the c* fields from p->signal from races with exit.c updating those
1574  * fields when reaping, so a sample either gets all the additions of a
1575  * given child after it's reaped, or none so this sample is before reaping.
1576  */
1577
1578 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1579 {
1580         struct task_struct *t;
1581         unsigned long flags;
1582         cputime_t utime, stime;
1583
1584         memset((char *) r, 0, sizeof *r);
1585
1586         if (unlikely(!p->signal))
1587                 return;
1588
1589         switch (who) {
1590                 case RUSAGE_CHILDREN:
1591                         spin_lock_irqsave(&p->sighand->siglock, flags);
1592                         utime = p->signal->cutime;
1593                         stime = p->signal->cstime;
1594                         r->ru_nvcsw = p->signal->cnvcsw;
1595                         r->ru_nivcsw = p->signal->cnivcsw;
1596                         r->ru_minflt = p->signal->cmin_flt;
1597                         r->ru_majflt = p->signal->cmaj_flt;
1598                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1599                         cputime_to_timeval(utime, &r->ru_utime);
1600                         cputime_to_timeval(stime, &r->ru_stime);
1601                         break;
1602                 case RUSAGE_SELF:
1603                         spin_lock_irqsave(&p->sighand->siglock, flags);
1604                         utime = stime = cputime_zero;
1605                         goto sum_group;
1606                 case RUSAGE_BOTH:
1607                         spin_lock_irqsave(&p->sighand->siglock, flags);
1608                         utime = p->signal->cutime;
1609                         stime = p->signal->cstime;
1610                         r->ru_nvcsw = p->signal->cnvcsw;
1611                         r->ru_nivcsw = p->signal->cnivcsw;
1612                         r->ru_minflt = p->signal->cmin_flt;
1613                         r->ru_majflt = p->signal->cmaj_flt;
1614                 sum_group:
1615                         utime = cputime_add(utime, p->signal->utime);
1616                         stime = cputime_add(stime, p->signal->stime);
1617                         r->ru_nvcsw += p->signal->nvcsw;
1618                         r->ru_nivcsw += p->signal->nivcsw;
1619                         r->ru_minflt += p->signal->min_flt;
1620                         r->ru_majflt += p->signal->maj_flt;
1621                         t = p;
1622                         do {
1623                                 utime = cputime_add(utime, t->utime);
1624                                 stime = cputime_add(stime, t->stime);
1625                                 r->ru_nvcsw += t->nvcsw;
1626                                 r->ru_nivcsw += t->nivcsw;
1627                                 r->ru_minflt += t->min_flt;
1628                                 r->ru_majflt += t->maj_flt;
1629                                 t = next_thread(t);
1630                         } while (t != p);
1631                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1632                         cputime_to_timeval(utime, &r->ru_utime);
1633                         cputime_to_timeval(stime, &r->ru_stime);
1634                         break;
1635                 default:
1636                         BUG();
1637         }
1638 }
1639
1640 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1641 {
1642         struct rusage r;
1643         read_lock(&tasklist_lock);
1644         k_getrusage(p, who, &r);
1645         read_unlock(&tasklist_lock);
1646         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1647 }
1648
1649 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1650 {
1651         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1652                 return -EINVAL;
1653         return getrusage(current, who, ru);
1654 }
1655
1656 asmlinkage long sys_umask(int mask)
1657 {
1658         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1659         return mask;
1660 }
1661
1662 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1663                           unsigned long arg4, unsigned long arg5)
1664 {
1665         long error;
1666         int sig;
1667
1668         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1669         if (error)
1670                 return error;
1671
1672         switch (option) {
1673                 case PR_SET_PDEATHSIG:
1674                         sig = arg2;
1675                         if (!valid_signal(sig)) {
1676                                 error = -EINVAL;
1677                                 break;
1678                         }
1679                         current->pdeath_signal = sig;
1680                         break;
1681                 case PR_GET_PDEATHSIG:
1682                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1683                         break;
1684                 case PR_GET_DUMPABLE:
1685                         if (current->mm->dumpable)
1686                                 error = 1;
1687                         break;
1688                 case PR_SET_DUMPABLE:
1689                         if (arg2 < 0 || arg2 > 2) {
1690                                 error = -EINVAL;
1691                                 break;
1692                         }
1693                         current->mm->dumpable = arg2;
1694                         break;
1695
1696                 case PR_SET_UNALIGN:
1697                         error = SET_UNALIGN_CTL(current, arg2);
1698                         break;
1699                 case PR_GET_UNALIGN:
1700                         error = GET_UNALIGN_CTL(current, arg2);
1701                         break;
1702                 case PR_SET_FPEMU:
1703                         error = SET_FPEMU_CTL(current, arg2);
1704                         break;
1705                 case PR_GET_FPEMU:
1706                         error = GET_FPEMU_CTL(current, arg2);
1707                         break;
1708                 case PR_SET_FPEXC:
1709                         error = SET_FPEXC_CTL(current, arg2);
1710                         break;
1711                 case PR_GET_FPEXC:
1712                         error = GET_FPEXC_CTL(current, arg2);
1713                         break;
1714                 case PR_GET_TIMING:
1715                         error = PR_TIMING_STATISTICAL;
1716                         break;
1717                 case PR_SET_TIMING:
1718                         if (arg2 == PR_TIMING_STATISTICAL)
1719                                 error = 0;
1720                         else
1721                                 error = -EINVAL;
1722                         break;
1723
1724                 case PR_GET_KEEPCAPS:
1725                         if (current->keep_capabilities)
1726                                 error = 1;
1727                         break;
1728                 case PR_SET_KEEPCAPS:
1729                         if (arg2 != 0 && arg2 != 1) {
1730                                 error = -EINVAL;
1731                                 break;
1732                         }
1733                         current->keep_capabilities = arg2;
1734                         break;
1735                 case PR_SET_NAME: {
1736                         struct task_struct *me = current;
1737                         unsigned char ncomm[sizeof(me->comm)];
1738
1739                         ncomm[sizeof(me->comm)-1] = 0;
1740                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1741                                                 sizeof(me->comm)-1) < 0)
1742                                 return -EFAULT;
1743                         set_task_comm(me, ncomm);
1744                         return 0;
1745                 }
1746                 case PR_GET_NAME: {
1747                         struct task_struct *me = current;
1748                         unsigned char tcomm[sizeof(me->comm)];
1749
1750                         get_task_comm(tcomm, me);
1751                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1752                                 return -EFAULT;
1753                         return 0;
1754                 }
1755                 default:
1756                         error = -EINVAL;
1757                         break;
1758         }
1759         return error;
1760 }