[PATCH] reboot: comment and factor the main reboot functions
[linux-2.6.git] / 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  *      emergency_restart - reboot the system
366  *
367  *      Without shutting down any hardware or taking any locks
368  *      reboot the system.  This is called when we know we are in
369  *      trouble so this is our best effort to reboot.  This is
370  *      safe to call in interrupt context.
371  */
372 void emergency_restart(void)
373 {
374         machine_emergency_restart();
375 }
376 EXPORT_SYMBOL_GPL(emergency_restart);
377
378 /**
379  *      kernel_restart - reboot the system
380  *
381  *      Shutdown everything and perform a clean reboot.
382  *      This is not safe to call in interrupt context.
383  */
384 void kernel_restart_prepare(char *cmd)
385 {
386         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
387         system_state = SYSTEM_RESTART;
388         device_shutdown();
389 }
390 void kernel_restart(char *cmd)
391 {
392         kernel_restart_prepare(cmd);
393         if (!cmd) {
394                 printk(KERN_EMERG "Restarting system.\n");
395         } else {
396                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
397         }
398         printk(".\n");
399         machine_restart(cmd);
400 }
401 EXPORT_SYMBOL_GPL(kernel_restart);
402
403 /**
404  *      kernel_kexec - reboot the system
405  *
406  *      Move into place and start executing a preloaded standalone
407  *      executable.  If nothing was preloaded return an error.
408  */
409 void kernel_kexec(void)
410 {
411 #ifdef CONFIG_KEXEC
412         struct kimage *image;
413         image = xchg(&kexec_image, 0);
414         if (!image) {
415                 return;
416         }
417         kernel_restart_prepare(NULL);
418         printk(KERN_EMERG "Starting new kernel\n");
419         machine_shutdown();
420         machine_kexec(image);
421 #endif
422 }
423 EXPORT_SYMBOL_GPL(kernel_kexec);
424
425 /**
426  *      kernel_halt - halt the system
427  *
428  *      Shutdown everything and perform a clean system halt.
429  */
430 void kernel_halt_prepare(void)
431 {
432         notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
433         system_state = SYSTEM_HALT;
434         device_shutdown();
435 }
436 void kernel_halt(void)
437 {
438         kernel_halt_prepare();
439         printk(KERN_EMERG "System halted.\n");
440         machine_halt();
441 }
442 EXPORT_SYMBOL_GPL(kernel_halt);
443
444 /**
445  *      kernel_power_off - power_off the system
446  *
447  *      Shutdown everything and perform a clean system power_off.
448  */
449 void kernel_power_off_prepare(void)
450 {
451         notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
452         system_state = SYSTEM_POWER_OFF;
453         device_shutdown();
454 }
455 void kernel_power_off(void)
456 {
457         kernel_power_off_prepare();
458         printk(KERN_EMERG "Power down.\n");
459         machine_power_off();
460 }
461 EXPORT_SYMBOL_GPL(kernel_power_off);
462
463 /*
464  * Reboot system call: for obvious reasons only root may call it,
465  * and even root needs to set up some magic numbers in the registers
466  * so that some mistake won't make this reboot the whole machine.
467  * You can also set the meaning of the ctrl-alt-del-key here.
468  *
469  * reboot doesn't sync: do that yourself before calling this.
470  */
471 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
472 {
473         char buffer[256];
474
475         /* We only trust the superuser with rebooting the system. */
476         if (!capable(CAP_SYS_BOOT))
477                 return -EPERM;
478
479         /* For safety, we require "magic" arguments. */
480         if (magic1 != LINUX_REBOOT_MAGIC1 ||
481             (magic2 != LINUX_REBOOT_MAGIC2 &&
482                         magic2 != LINUX_REBOOT_MAGIC2A &&
483                         magic2 != LINUX_REBOOT_MAGIC2B &&
484                         magic2 != LINUX_REBOOT_MAGIC2C))
485                 return -EINVAL;
486
487         lock_kernel();
488         switch (cmd) {
489         case LINUX_REBOOT_CMD_RESTART:
490                 kernel_restart(NULL);
491                 break;
492
493         case LINUX_REBOOT_CMD_CAD_ON:
494                 C_A_D = 1;
495                 break;
496
497         case LINUX_REBOOT_CMD_CAD_OFF:
498                 C_A_D = 0;
499                 break;
500
501         case LINUX_REBOOT_CMD_HALT:
502                 kernel_halt();
503                 unlock_kernel();
504                 do_exit(0);
505                 break;
506
507         case LINUX_REBOOT_CMD_POWER_OFF:
508                 kernel_power_off();
509                 unlock_kernel();
510                 do_exit(0);
511                 break;
512
513         case LINUX_REBOOT_CMD_RESTART2:
514                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
515                         unlock_kernel();
516                         return -EFAULT;
517                 }
518                 buffer[sizeof(buffer) - 1] = '\0';
519
520                 kernel_restart(buffer);
521                 break;
522
523         case LINUX_REBOOT_CMD_KEXEC:
524                 kernel_kexec();
525                 unlock_kernel();
526                 return -EINVAL;
527
528 #ifdef CONFIG_SOFTWARE_SUSPEND
529         case LINUX_REBOOT_CMD_SW_SUSPEND:
530                 {
531                         int ret = software_suspend();
532                         unlock_kernel();
533                         return ret;
534                 }
535 #endif
536
537         default:
538                 unlock_kernel();
539                 return -EINVAL;
540         }
541         unlock_kernel();
542         return 0;
543 }
544
545 static void deferred_cad(void *dummy)
546 {
547         kernel_restart(NULL);
548 }
549
550 /*
551  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
552  * As it's called within an interrupt, it may NOT sync: the only choice
553  * is whether to reboot at once, or just ignore the ctrl-alt-del.
554  */
555 void ctrl_alt_del(void)
556 {
557         static DECLARE_WORK(cad_work, deferred_cad, NULL);
558
559         if (C_A_D)
560                 schedule_work(&cad_work);
561         else
562                 kill_proc(cad_pid, SIGINT, 1);
563 }
564         
565
566 /*
567  * Unprivileged users may change the real gid to the effective gid
568  * or vice versa.  (BSD-style)
569  *
570  * If you set the real gid at all, or set the effective gid to a value not
571  * equal to the real gid, then the saved gid is set to the new effective gid.
572  *
573  * This makes it possible for a setgid program to completely drop its
574  * privileges, which is often a useful assertion to make when you are doing
575  * a security audit over a program.
576  *
577  * The general idea is that a program which uses just setregid() will be
578  * 100% compatible with BSD.  A program which uses just setgid() will be
579  * 100% compatible with POSIX with saved IDs. 
580  *
581  * SMP: There are not races, the GIDs are checked only by filesystem
582  *      operations (as far as semantic preservation is concerned).
583  */
584 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
585 {
586         int old_rgid = current->gid;
587         int old_egid = current->egid;
588         int new_rgid = old_rgid;
589         int new_egid = old_egid;
590         int retval;
591
592         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
593         if (retval)
594                 return retval;
595
596         if (rgid != (gid_t) -1) {
597                 if ((old_rgid == rgid) ||
598                     (current->egid==rgid) ||
599                     capable(CAP_SETGID))
600                         new_rgid = rgid;
601                 else
602                         return -EPERM;
603         }
604         if (egid != (gid_t) -1) {
605                 if ((old_rgid == egid) ||
606                     (current->egid == egid) ||
607                     (current->sgid == egid) ||
608                     capable(CAP_SETGID))
609                         new_egid = egid;
610                 else {
611                         return -EPERM;
612                 }
613         }
614         if (new_egid != old_egid)
615         {
616                 current->mm->dumpable = suid_dumpable;
617                 smp_wmb();
618         }
619         if (rgid != (gid_t) -1 ||
620             (egid != (gid_t) -1 && egid != old_rgid))
621                 current->sgid = new_egid;
622         current->fsgid = new_egid;
623         current->egid = new_egid;
624         current->gid = new_rgid;
625         key_fsgid_changed(current);
626         return 0;
627 }
628
629 /*
630  * setgid() is implemented like SysV w/ SAVED_IDS 
631  *
632  * SMP: Same implicit races as above.
633  */
634 asmlinkage long sys_setgid(gid_t gid)
635 {
636         int old_egid = current->egid;
637         int retval;
638
639         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
640         if (retval)
641                 return retval;
642
643         if (capable(CAP_SETGID))
644         {
645                 if(old_egid != gid)
646                 {
647                         current->mm->dumpable = suid_dumpable;
648                         smp_wmb();
649                 }
650                 current->gid = current->egid = current->sgid = current->fsgid = gid;
651         }
652         else if ((gid == current->gid) || (gid == current->sgid))
653         {
654                 if(old_egid != gid)
655                 {
656                         current->mm->dumpable = suid_dumpable;
657                         smp_wmb();
658                 }
659                 current->egid = current->fsgid = gid;
660         }
661         else
662                 return -EPERM;
663
664         key_fsgid_changed(current);
665         return 0;
666 }
667   
668 static int set_user(uid_t new_ruid, int dumpclear)
669 {
670         struct user_struct *new_user;
671
672         new_user = alloc_uid(new_ruid);
673         if (!new_user)
674                 return -EAGAIN;
675
676         if (atomic_read(&new_user->processes) >=
677                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
678                         new_user != &root_user) {
679                 free_uid(new_user);
680                 return -EAGAIN;
681         }
682
683         switch_uid(new_user);
684
685         if(dumpclear)
686         {
687                 current->mm->dumpable = suid_dumpable;
688                 smp_wmb();
689         }
690         current->uid = new_ruid;
691         return 0;
692 }
693
694 /*
695  * Unprivileged users may change the real uid to the effective uid
696  * or vice versa.  (BSD-style)
697  *
698  * If you set the real uid at all, or set the effective uid to a value not
699  * equal to the real uid, then the saved uid is set to the new effective uid.
700  *
701  * This makes it possible for a setuid program to completely drop its
702  * privileges, which is often a useful assertion to make when you are doing
703  * a security audit over a program.
704  *
705  * The general idea is that a program which uses just setreuid() will be
706  * 100% compatible with BSD.  A program which uses just setuid() will be
707  * 100% compatible with POSIX with saved IDs. 
708  */
709 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
710 {
711         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
712         int retval;
713
714         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
715         if (retval)
716                 return retval;
717
718         new_ruid = old_ruid = current->uid;
719         new_euid = old_euid = current->euid;
720         old_suid = current->suid;
721
722         if (ruid != (uid_t) -1) {
723                 new_ruid = ruid;
724                 if ((old_ruid != ruid) &&
725                     (current->euid != ruid) &&
726                     !capable(CAP_SETUID))
727                         return -EPERM;
728         }
729
730         if (euid != (uid_t) -1) {
731                 new_euid = euid;
732                 if ((old_ruid != euid) &&
733                     (current->euid != euid) &&
734                     (current->suid != euid) &&
735                     !capable(CAP_SETUID))
736                         return -EPERM;
737         }
738
739         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
740                 return -EAGAIN;
741
742         if (new_euid != old_euid)
743         {
744                 current->mm->dumpable = suid_dumpable;
745                 smp_wmb();
746         }
747         current->fsuid = current->euid = new_euid;
748         if (ruid != (uid_t) -1 ||
749             (euid != (uid_t) -1 && euid != old_ruid))
750                 current->suid = current->euid;
751         current->fsuid = current->euid;
752
753         key_fsuid_changed(current);
754
755         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
756 }
757
758
759                 
760 /*
761  * setuid() is implemented like SysV with SAVED_IDS 
762  * 
763  * Note that SAVED_ID's is deficient in that a setuid root program
764  * like sendmail, for example, cannot set its uid to be a normal 
765  * user and then switch back, because if you're root, setuid() sets
766  * the saved uid too.  If you don't like this, blame the bright people
767  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
768  * will allow a root program to temporarily drop privileges and be able to
769  * regain them by swapping the real and effective uid.  
770  */
771 asmlinkage long sys_setuid(uid_t uid)
772 {
773         int old_euid = current->euid;
774         int old_ruid, old_suid, new_ruid, new_suid;
775         int retval;
776
777         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
778         if (retval)
779                 return retval;
780
781         old_ruid = new_ruid = current->uid;
782         old_suid = current->suid;
783         new_suid = old_suid;
784         
785         if (capable(CAP_SETUID)) {
786                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
787                         return -EAGAIN;
788                 new_suid = uid;
789         } else if ((uid != current->uid) && (uid != new_suid))
790                 return -EPERM;
791
792         if (old_euid != uid)
793         {
794                 current->mm->dumpable = suid_dumpable;
795                 smp_wmb();
796         }
797         current->fsuid = current->euid = uid;
798         current->suid = new_suid;
799
800         key_fsuid_changed(current);
801
802         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
803 }
804
805
806 /*
807  * This function implements a generic ability to update ruid, euid,
808  * and suid.  This allows you to implement the 4.4 compatible seteuid().
809  */
810 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
811 {
812         int old_ruid = current->uid;
813         int old_euid = current->euid;
814         int old_suid = current->suid;
815         int retval;
816
817         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
818         if (retval)
819                 return retval;
820
821         if (!capable(CAP_SETUID)) {
822                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
823                     (ruid != current->euid) && (ruid != current->suid))
824                         return -EPERM;
825                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
826                     (euid != current->euid) && (euid != current->suid))
827                         return -EPERM;
828                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
829                     (suid != current->euid) && (suid != current->suid))
830                         return -EPERM;
831         }
832         if (ruid != (uid_t) -1) {
833                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
834                         return -EAGAIN;
835         }
836         if (euid != (uid_t) -1) {
837                 if (euid != current->euid)
838                 {
839                         current->mm->dumpable = suid_dumpable;
840                         smp_wmb();
841                 }
842                 current->euid = euid;
843         }
844         current->fsuid = current->euid;
845         if (suid != (uid_t) -1)
846                 current->suid = suid;
847
848         key_fsuid_changed(current);
849
850         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
851 }
852
853 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
854 {
855         int retval;
856
857         if (!(retval = put_user(current->uid, ruid)) &&
858             !(retval = put_user(current->euid, euid)))
859                 retval = put_user(current->suid, suid);
860
861         return retval;
862 }
863
864 /*
865  * Same as above, but for rgid, egid, sgid.
866  */
867 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
868 {
869         int retval;
870
871         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
872         if (retval)
873                 return retval;
874
875         if (!capable(CAP_SETGID)) {
876                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
877                     (rgid != current->egid) && (rgid != current->sgid))
878                         return -EPERM;
879                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
880                     (egid != current->egid) && (egid != current->sgid))
881                         return -EPERM;
882                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
883                     (sgid != current->egid) && (sgid != current->sgid))
884                         return -EPERM;
885         }
886         if (egid != (gid_t) -1) {
887                 if (egid != current->egid)
888                 {
889                         current->mm->dumpable = suid_dumpable;
890                         smp_wmb();
891                 }
892                 current->egid = egid;
893         }
894         current->fsgid = current->egid;
895         if (rgid != (gid_t) -1)
896                 current->gid = rgid;
897         if (sgid != (gid_t) -1)
898                 current->sgid = sgid;
899
900         key_fsgid_changed(current);
901         return 0;
902 }
903
904 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
905 {
906         int retval;
907
908         if (!(retval = put_user(current->gid, rgid)) &&
909             !(retval = put_user(current->egid, egid)))
910                 retval = put_user(current->sgid, sgid);
911
912         return retval;
913 }
914
915
916 /*
917  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
918  * is used for "access()" and for the NFS daemon (letting nfsd stay at
919  * whatever uid it wants to). It normally shadows "euid", except when
920  * explicitly set by setfsuid() or for access..
921  */
922 asmlinkage long sys_setfsuid(uid_t uid)
923 {
924         int old_fsuid;
925
926         old_fsuid = current->fsuid;
927         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
928                 return old_fsuid;
929
930         if (uid == current->uid || uid == current->euid ||
931             uid == current->suid || uid == current->fsuid || 
932             capable(CAP_SETUID))
933         {
934                 if (uid != old_fsuid)
935                 {
936                         current->mm->dumpable = suid_dumpable;
937                         smp_wmb();
938                 }
939                 current->fsuid = uid;
940         }
941
942         key_fsuid_changed(current);
943
944         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
945
946         return old_fsuid;
947 }
948
949 /*
950  * Samma på svenska..
951  */
952 asmlinkage long sys_setfsgid(gid_t gid)
953 {
954         int old_fsgid;
955
956         old_fsgid = current->fsgid;
957         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
958                 return old_fsgid;
959
960         if (gid == current->gid || gid == current->egid ||
961             gid == current->sgid || gid == current->fsgid || 
962             capable(CAP_SETGID))
963         {
964                 if (gid != old_fsgid)
965                 {
966                         current->mm->dumpable = suid_dumpable;
967                         smp_wmb();
968                 }
969                 current->fsgid = gid;
970                 key_fsgid_changed(current);
971         }
972         return old_fsgid;
973 }
974
975 asmlinkage long sys_times(struct tms __user * tbuf)
976 {
977         /*
978          *      In the SMP world we might just be unlucky and have one of
979          *      the times increment as we use it. Since the value is an
980          *      atomically safe type this is just fine. Conceptually its
981          *      as if the syscall took an instant longer to occur.
982          */
983         if (tbuf) {
984                 struct tms tmp;
985                 cputime_t utime, stime, cutime, cstime;
986
987 #ifdef CONFIG_SMP
988                 if (thread_group_empty(current)) {
989                         /*
990                          * Single thread case without the use of any locks.
991                          *
992                          * We may race with release_task if two threads are
993                          * executing. However, release task first adds up the
994                          * counters (__exit_signal) before  removing the task
995                          * from the process tasklist (__unhash_process).
996                          * __exit_signal also acquires and releases the
997                          * siglock which results in the proper memory ordering
998                          * so that the list modifications are always visible
999                          * after the counters have been updated.
1000                          *
1001                          * If the counters have been updated by the second thread
1002                          * but the thread has not yet been removed from the list
1003                          * then the other branch will be executing which will
1004                          * block on tasklist_lock until the exit handling of the
1005                          * other task is finished.
1006                          *
1007                          * This also implies that the sighand->siglock cannot
1008                          * be held by another processor. So we can also
1009                          * skip acquiring that lock.
1010                          */
1011                         utime = cputime_add(current->signal->utime, current->utime);
1012                         stime = cputime_add(current->signal->utime, current->stime);
1013                         cutime = current->signal->cutime;
1014                         cstime = current->signal->cstime;
1015                 } else
1016 #endif
1017                 {
1018
1019                         /* Process with multiple threads */
1020                         struct task_struct *tsk = current;
1021                         struct task_struct *t;
1022
1023                         read_lock(&tasklist_lock);
1024                         utime = tsk->signal->utime;
1025                         stime = tsk->signal->stime;
1026                         t = tsk;
1027                         do {
1028                                 utime = cputime_add(utime, t->utime);
1029                                 stime = cputime_add(stime, t->stime);
1030                                 t = next_thread(t);
1031                         } while (t != tsk);
1032
1033                         /*
1034                          * While we have tasklist_lock read-locked, no dying thread
1035                          * can be updating current->signal->[us]time.  Instead,
1036                          * we got their counts included in the live thread loop.
1037                          * However, another thread can come in right now and
1038                          * do a wait call that updates current->signal->c[us]time.
1039                          * To make sure we always see that pair updated atomically,
1040                          * we take the siglock around fetching them.
1041                          */
1042                         spin_lock_irq(&tsk->sighand->siglock);
1043                         cutime = tsk->signal->cutime;
1044                         cstime = tsk->signal->cstime;
1045                         spin_unlock_irq(&tsk->sighand->siglock);
1046                         read_unlock(&tasklist_lock);
1047                 }
1048                 tmp.tms_utime = cputime_to_clock_t(utime);
1049                 tmp.tms_stime = cputime_to_clock_t(stime);
1050                 tmp.tms_cutime = cputime_to_clock_t(cutime);
1051                 tmp.tms_cstime = cputime_to_clock_t(cstime);
1052                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1053                         return -EFAULT;
1054         }
1055         return (long) jiffies_64_to_clock_t(get_jiffies_64());
1056 }
1057
1058 /*
1059  * This needs some heavy checking ...
1060  * I just haven't the stomach for it. I also don't fully
1061  * understand sessions/pgrp etc. Let somebody who does explain it.
1062  *
1063  * OK, I think I have the protection semantics right.... this is really
1064  * only important on a multi-user system anyway, to make sure one user
1065  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1066  *
1067  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1068  * LBT 04.03.94
1069  */
1070
1071 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1072 {
1073         struct task_struct *p;
1074         int err = -EINVAL;
1075
1076         if (!pid)
1077                 pid = current->pid;
1078         if (!pgid)
1079                 pgid = pid;
1080         if (pgid < 0)
1081                 return -EINVAL;
1082
1083         /* From this point forward we keep holding onto the tasklist lock
1084          * so that our parent does not change from under us. -DaveM
1085          */
1086         write_lock_irq(&tasklist_lock);
1087
1088         err = -ESRCH;
1089         p = find_task_by_pid(pid);
1090         if (!p)
1091                 goto out;
1092
1093         err = -EINVAL;
1094         if (!thread_group_leader(p))
1095                 goto out;
1096
1097         if (p->parent == current || p->real_parent == current) {
1098                 err = -EPERM;
1099                 if (p->signal->session != current->signal->session)
1100                         goto out;
1101                 err = -EACCES;
1102                 if (p->did_exec)
1103                         goto out;
1104         } else {
1105                 err = -ESRCH;
1106                 if (p != current)
1107                         goto out;
1108         }
1109
1110         err = -EPERM;
1111         if (p->signal->leader)
1112                 goto out;
1113
1114         if (pgid != pid) {
1115                 struct task_struct *p;
1116
1117                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1118                         if (p->signal->session == current->signal->session)
1119                                 goto ok_pgid;
1120                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1121                 goto out;
1122         }
1123
1124 ok_pgid:
1125         err = security_task_setpgid(p, pgid);
1126         if (err)
1127                 goto out;
1128
1129         if (process_group(p) != pgid) {
1130                 detach_pid(p, PIDTYPE_PGID);
1131                 p->signal->pgrp = pgid;
1132                 attach_pid(p, PIDTYPE_PGID, pgid);
1133         }
1134
1135         err = 0;
1136 out:
1137         /* All paths lead to here, thus we are safe. -DaveM */
1138         write_unlock_irq(&tasklist_lock);
1139         return err;
1140 }
1141
1142 asmlinkage long sys_getpgid(pid_t pid)
1143 {
1144         if (!pid) {
1145                 return process_group(current);
1146         } else {
1147                 int retval;
1148                 struct task_struct *p;
1149
1150                 read_lock(&tasklist_lock);
1151                 p = find_task_by_pid(pid);
1152
1153                 retval = -ESRCH;
1154                 if (p) {
1155                         retval = security_task_getpgid(p);
1156                         if (!retval)
1157                                 retval = process_group(p);
1158                 }
1159                 read_unlock(&tasklist_lock);
1160                 return retval;
1161         }
1162 }
1163
1164 #ifdef __ARCH_WANT_SYS_GETPGRP
1165
1166 asmlinkage long sys_getpgrp(void)
1167 {
1168         /* SMP - assuming writes are word atomic this is fine */
1169         return process_group(current);
1170 }
1171
1172 #endif
1173
1174 asmlinkage long sys_getsid(pid_t pid)
1175 {
1176         if (!pid) {
1177                 return current->signal->session;
1178         } else {
1179                 int retval;
1180                 struct task_struct *p;
1181
1182                 read_lock(&tasklist_lock);
1183                 p = find_task_by_pid(pid);
1184
1185                 retval = -ESRCH;
1186                 if(p) {
1187                         retval = security_task_getsid(p);
1188                         if (!retval)
1189                                 retval = p->signal->session;
1190                 }
1191                 read_unlock(&tasklist_lock);
1192                 return retval;
1193         }
1194 }
1195
1196 asmlinkage long sys_setsid(void)
1197 {
1198         struct pid *pid;
1199         int err = -EPERM;
1200
1201         if (!thread_group_leader(current))
1202                 return -EINVAL;
1203
1204         down(&tty_sem);
1205         write_lock_irq(&tasklist_lock);
1206
1207         pid = find_pid(PIDTYPE_PGID, current->pid);
1208         if (pid)
1209                 goto out;
1210
1211         current->signal->leader = 1;
1212         __set_special_pids(current->pid, current->pid);
1213         current->signal->tty = NULL;
1214         current->signal->tty_old_pgrp = 0;
1215         err = process_group(current);
1216 out:
1217         write_unlock_irq(&tasklist_lock);
1218         up(&tty_sem);
1219         return err;
1220 }
1221
1222 /*
1223  * Supplementary group IDs
1224  */
1225
1226 /* init to 2 - one for init_task, one to ensure it is never freed */
1227 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1228
1229 struct group_info *groups_alloc(int gidsetsize)
1230 {
1231         struct group_info *group_info;
1232         int nblocks;
1233         int i;
1234
1235         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1236         /* Make sure we always allocate at least one indirect block pointer */
1237         nblocks = nblocks ? : 1;
1238         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1239         if (!group_info)
1240                 return NULL;
1241         group_info->ngroups = gidsetsize;
1242         group_info->nblocks = nblocks;
1243         atomic_set(&group_info->usage, 1);
1244
1245         if (gidsetsize <= NGROUPS_SMALL) {
1246                 group_info->blocks[0] = group_info->small_block;
1247         } else {
1248                 for (i = 0; i < nblocks; i++) {
1249                         gid_t *b;
1250                         b = (void *)__get_free_page(GFP_USER);
1251                         if (!b)
1252                                 goto out_undo_partial_alloc;
1253                         group_info->blocks[i] = b;
1254                 }
1255         }
1256         return group_info;
1257
1258 out_undo_partial_alloc:
1259         while (--i >= 0) {
1260                 free_page((unsigned long)group_info->blocks[i]);
1261         }
1262         kfree(group_info);
1263         return NULL;
1264 }
1265
1266 EXPORT_SYMBOL(groups_alloc);
1267
1268 void groups_free(struct group_info *group_info)
1269 {
1270         if (group_info->blocks[0] != group_info->small_block) {
1271                 int i;
1272                 for (i = 0; i < group_info->nblocks; i++)
1273                         free_page((unsigned long)group_info->blocks[i]);
1274         }
1275         kfree(group_info);
1276 }
1277
1278 EXPORT_SYMBOL(groups_free);
1279
1280 /* export the group_info to a user-space array */
1281 static int groups_to_user(gid_t __user *grouplist,
1282     struct group_info *group_info)
1283 {
1284         int i;
1285         int count = group_info->ngroups;
1286
1287         for (i = 0; i < group_info->nblocks; i++) {
1288                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1289                 int off = i * NGROUPS_PER_BLOCK;
1290                 int len = cp_count * sizeof(*grouplist);
1291
1292                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1293                         return -EFAULT;
1294
1295                 count -= cp_count;
1296         }
1297         return 0;
1298 }
1299
1300 /* fill a group_info from a user-space array - it must be allocated already */
1301 static int groups_from_user(struct group_info *group_info,
1302     gid_t __user *grouplist)
1303  {
1304         int i;
1305         int count = group_info->ngroups;
1306
1307         for (i = 0; i < group_info->nblocks; i++) {
1308                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1309                 int off = i * NGROUPS_PER_BLOCK;
1310                 int len = cp_count * sizeof(*grouplist);
1311
1312                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1313                         return -EFAULT;
1314
1315                 count -= cp_count;
1316         }
1317         return 0;
1318 }
1319
1320 /* a simple Shell sort */
1321 static void groups_sort(struct group_info *group_info)
1322 {
1323         int base, max, stride;
1324         int gidsetsize = group_info->ngroups;
1325
1326         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1327                 ; /* nothing */
1328         stride /= 3;
1329
1330         while (stride) {
1331                 max = gidsetsize - stride;
1332                 for (base = 0; base < max; base++) {
1333                         int left = base;
1334                         int right = left + stride;
1335                         gid_t tmp = GROUP_AT(group_info, right);
1336
1337                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1338                                 GROUP_AT(group_info, right) =
1339                                     GROUP_AT(group_info, left);
1340                                 right = left;
1341                                 left -= stride;
1342                         }
1343                         GROUP_AT(group_info, right) = tmp;
1344                 }
1345                 stride /= 3;
1346         }
1347 }
1348
1349 /* a simple bsearch */
1350 int groups_search(struct group_info *group_info, gid_t grp)
1351 {
1352         int left, right;
1353
1354         if (!group_info)
1355                 return 0;
1356
1357         left = 0;
1358         right = group_info->ngroups;
1359         while (left < right) {
1360                 int mid = (left+right)/2;
1361                 int cmp = grp - GROUP_AT(group_info, mid);
1362                 if (cmp > 0)
1363                         left = mid + 1;
1364                 else if (cmp < 0)
1365                         right = mid;
1366                 else
1367                         return 1;
1368         }
1369         return 0;
1370 }
1371
1372 /* validate and set current->group_info */
1373 int set_current_groups(struct group_info *group_info)
1374 {
1375         int retval;
1376         struct group_info *old_info;
1377
1378         retval = security_task_setgroups(group_info);
1379         if (retval)
1380                 return retval;
1381
1382         groups_sort(group_info);
1383         get_group_info(group_info);
1384
1385         task_lock(current);
1386         old_info = current->group_info;
1387         current->group_info = group_info;
1388         task_unlock(current);
1389
1390         put_group_info(old_info);
1391
1392         return 0;
1393 }
1394
1395 EXPORT_SYMBOL(set_current_groups);
1396
1397 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1398 {
1399         int i = 0;
1400
1401         /*
1402          *      SMP: Nobody else can change our grouplist. Thus we are
1403          *      safe.
1404          */
1405
1406         if (gidsetsize < 0)
1407                 return -EINVAL;
1408
1409         /* no need to grab task_lock here; it cannot change */
1410         get_group_info(current->group_info);
1411         i = current->group_info->ngroups;
1412         if (gidsetsize) {
1413                 if (i > gidsetsize) {
1414                         i = -EINVAL;
1415                         goto out;
1416                 }
1417                 if (groups_to_user(grouplist, current->group_info)) {
1418                         i = -EFAULT;
1419                         goto out;
1420                 }
1421         }
1422 out:
1423         put_group_info(current->group_info);
1424         return i;
1425 }
1426
1427 /*
1428  *      SMP: Our groups are copy-on-write. We can set them safely
1429  *      without another task interfering.
1430  */
1431  
1432 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1433 {
1434         struct group_info *group_info;
1435         int retval;
1436
1437         if (!capable(CAP_SETGID))
1438                 return -EPERM;
1439         if ((unsigned)gidsetsize > NGROUPS_MAX)
1440                 return -EINVAL;
1441
1442         group_info = groups_alloc(gidsetsize);
1443         if (!group_info)
1444                 return -ENOMEM;
1445         retval = groups_from_user(group_info, grouplist);
1446         if (retval) {
1447                 put_group_info(group_info);
1448                 return retval;
1449         }
1450
1451         retval = set_current_groups(group_info);
1452         put_group_info(group_info);
1453
1454         return retval;
1455 }
1456
1457 /*
1458  * Check whether we're fsgid/egid or in the supplemental group..
1459  */
1460 int in_group_p(gid_t grp)
1461 {
1462         int retval = 1;
1463         if (grp != current->fsgid) {
1464                 get_group_info(current->group_info);
1465                 retval = groups_search(current->group_info, grp);
1466                 put_group_info(current->group_info);
1467         }
1468         return retval;
1469 }
1470
1471 EXPORT_SYMBOL(in_group_p);
1472
1473 int in_egroup_p(gid_t grp)
1474 {
1475         int retval = 1;
1476         if (grp != current->egid) {
1477                 get_group_info(current->group_info);
1478                 retval = groups_search(current->group_info, grp);
1479                 put_group_info(current->group_info);
1480         }
1481         return retval;
1482 }
1483
1484 EXPORT_SYMBOL(in_egroup_p);
1485
1486 DECLARE_RWSEM(uts_sem);
1487
1488 EXPORT_SYMBOL(uts_sem);
1489
1490 asmlinkage long sys_newuname(struct new_utsname __user * name)
1491 {
1492         int errno = 0;
1493
1494         down_read(&uts_sem);
1495         if (copy_to_user(name,&system_utsname,sizeof *name))
1496                 errno = -EFAULT;
1497         up_read(&uts_sem);
1498         return errno;
1499 }
1500
1501 asmlinkage long sys_sethostname(char __user *name, int len)
1502 {
1503         int errno;
1504         char tmp[__NEW_UTS_LEN];
1505
1506         if (!capable(CAP_SYS_ADMIN))
1507                 return -EPERM;
1508         if (len < 0 || len > __NEW_UTS_LEN)
1509                 return -EINVAL;
1510         down_write(&uts_sem);
1511         errno = -EFAULT;
1512         if (!copy_from_user(tmp, name, len)) {
1513                 memcpy(system_utsname.nodename, tmp, len);
1514                 system_utsname.nodename[len] = 0;
1515                 errno = 0;
1516         }
1517         up_write(&uts_sem);
1518         return errno;
1519 }
1520
1521 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1522
1523 asmlinkage long sys_gethostname(char __user *name, int len)
1524 {
1525         int i, errno;
1526
1527         if (len < 0)
1528                 return -EINVAL;
1529         down_read(&uts_sem);
1530         i = 1 + strlen(system_utsname.nodename);
1531         if (i > len)
1532                 i = len;
1533         errno = 0;
1534         if (copy_to_user(name, system_utsname.nodename, i))
1535                 errno = -EFAULT;
1536         up_read(&uts_sem);
1537         return errno;
1538 }
1539
1540 #endif
1541
1542 /*
1543  * Only setdomainname; getdomainname can be implemented by calling
1544  * uname()
1545  */
1546 asmlinkage long sys_setdomainname(char __user *name, int len)
1547 {
1548         int errno;
1549         char tmp[__NEW_UTS_LEN];
1550
1551         if (!capable(CAP_SYS_ADMIN))
1552                 return -EPERM;
1553         if (len < 0 || len > __NEW_UTS_LEN)
1554                 return -EINVAL;
1555
1556         down_write(&uts_sem);
1557         errno = -EFAULT;
1558         if (!copy_from_user(tmp, name, len)) {
1559                 memcpy(system_utsname.domainname, tmp, len);
1560                 system_utsname.domainname[len] = 0;
1561                 errno = 0;
1562         }
1563         up_write(&uts_sem);
1564         return errno;
1565 }
1566
1567 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1568 {
1569         if (resource >= RLIM_NLIMITS)
1570                 return -EINVAL;
1571         else {
1572                 struct rlimit value;
1573                 task_lock(current->group_leader);
1574                 value = current->signal->rlim[resource];
1575                 task_unlock(current->group_leader);
1576                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1577         }
1578 }
1579
1580 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1581
1582 /*
1583  *      Back compatibility for getrlimit. Needed for some apps.
1584  */
1585  
1586 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1587 {
1588         struct rlimit x;
1589         if (resource >= RLIM_NLIMITS)
1590                 return -EINVAL;
1591
1592         task_lock(current->group_leader);
1593         x = current->signal->rlim[resource];
1594         task_unlock(current->group_leader);
1595         if(x.rlim_cur > 0x7FFFFFFF)
1596                 x.rlim_cur = 0x7FFFFFFF;
1597         if(x.rlim_max > 0x7FFFFFFF)
1598                 x.rlim_max = 0x7FFFFFFF;
1599         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1600 }
1601
1602 #endif
1603
1604 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1605 {
1606         struct rlimit new_rlim, *old_rlim;
1607         int retval;
1608
1609         if (resource >= RLIM_NLIMITS)
1610                 return -EINVAL;
1611         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1612                 return -EFAULT;
1613        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1614                return -EINVAL;
1615         old_rlim = current->signal->rlim + resource;
1616         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1617             !capable(CAP_SYS_RESOURCE))
1618                 return -EPERM;
1619         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1620                         return -EPERM;
1621
1622         retval = security_task_setrlimit(resource, &new_rlim);
1623         if (retval)
1624                 return retval;
1625
1626         task_lock(current->group_leader);
1627         *old_rlim = new_rlim;
1628         task_unlock(current->group_leader);
1629
1630         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1631             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1632              new_rlim.rlim_cur <= cputime_to_secs(
1633                      current->signal->it_prof_expires))) {
1634                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1635                 read_lock(&tasklist_lock);
1636                 spin_lock_irq(&current->sighand->siglock);
1637                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1638                                       &cputime, NULL);
1639                 spin_unlock_irq(&current->sighand->siglock);
1640                 read_unlock(&tasklist_lock);
1641         }
1642
1643         return 0;
1644 }
1645
1646 /*
1647  * It would make sense to put struct rusage in the task_struct,
1648  * except that would make the task_struct be *really big*.  After
1649  * task_struct gets moved into malloc'ed memory, it would
1650  * make sense to do this.  It will make moving the rest of the information
1651  * a lot simpler!  (Which we're not doing right now because we're not
1652  * measuring them yet).
1653  *
1654  * This expects to be called with tasklist_lock read-locked or better,
1655  * and the siglock not locked.  It may momentarily take the siglock.
1656  *
1657  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1658  * races with threads incrementing their own counters.  But since word
1659  * reads are atomic, we either get new values or old values and we don't
1660  * care which for the sums.  We always take the siglock to protect reading
1661  * the c* fields from p->signal from races with exit.c updating those
1662  * fields when reaping, so a sample either gets all the additions of a
1663  * given child after it's reaped, or none so this sample is before reaping.
1664  */
1665
1666 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1667 {
1668         struct task_struct *t;
1669         unsigned long flags;
1670         cputime_t utime, stime;
1671
1672         memset((char *) r, 0, sizeof *r);
1673
1674         if (unlikely(!p->signal))
1675                 return;
1676
1677         switch (who) {
1678                 case RUSAGE_CHILDREN:
1679                         spin_lock_irqsave(&p->sighand->siglock, flags);
1680                         utime = p->signal->cutime;
1681                         stime = p->signal->cstime;
1682                         r->ru_nvcsw = p->signal->cnvcsw;
1683                         r->ru_nivcsw = p->signal->cnivcsw;
1684                         r->ru_minflt = p->signal->cmin_flt;
1685                         r->ru_majflt = p->signal->cmaj_flt;
1686                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1687                         cputime_to_timeval(utime, &r->ru_utime);
1688                         cputime_to_timeval(stime, &r->ru_stime);
1689                         break;
1690                 case RUSAGE_SELF:
1691                         spin_lock_irqsave(&p->sighand->siglock, flags);
1692                         utime = stime = cputime_zero;
1693                         goto sum_group;
1694                 case RUSAGE_BOTH:
1695                         spin_lock_irqsave(&p->sighand->siglock, flags);
1696                         utime = p->signal->cutime;
1697                         stime = p->signal->cstime;
1698                         r->ru_nvcsw = p->signal->cnvcsw;
1699                         r->ru_nivcsw = p->signal->cnivcsw;
1700                         r->ru_minflt = p->signal->cmin_flt;
1701                         r->ru_majflt = p->signal->cmaj_flt;
1702                 sum_group:
1703                         utime = cputime_add(utime, p->signal->utime);
1704                         stime = cputime_add(stime, p->signal->stime);
1705                         r->ru_nvcsw += p->signal->nvcsw;
1706                         r->ru_nivcsw += p->signal->nivcsw;
1707                         r->ru_minflt += p->signal->min_flt;
1708                         r->ru_majflt += p->signal->maj_flt;
1709                         t = p;
1710                         do {
1711                                 utime = cputime_add(utime, t->utime);
1712                                 stime = cputime_add(stime, t->stime);
1713                                 r->ru_nvcsw += t->nvcsw;
1714                                 r->ru_nivcsw += t->nivcsw;
1715                                 r->ru_minflt += t->min_flt;
1716                                 r->ru_majflt += t->maj_flt;
1717                                 t = next_thread(t);
1718                         } while (t != p);
1719                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1720                         cputime_to_timeval(utime, &r->ru_utime);
1721                         cputime_to_timeval(stime, &r->ru_stime);
1722                         break;
1723                 default:
1724                         BUG();
1725         }
1726 }
1727
1728 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1729 {
1730         struct rusage r;
1731         read_lock(&tasklist_lock);
1732         k_getrusage(p, who, &r);
1733         read_unlock(&tasklist_lock);
1734         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1735 }
1736
1737 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1738 {
1739         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1740                 return -EINVAL;
1741         return getrusage(current, who, ru);
1742 }
1743
1744 asmlinkage long sys_umask(int mask)
1745 {
1746         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1747         return mask;
1748 }
1749     
1750 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1751                           unsigned long arg4, unsigned long arg5)
1752 {
1753         long error;
1754
1755         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1756         if (error)
1757                 return error;
1758
1759         switch (option) {
1760                 case PR_SET_PDEATHSIG:
1761                         if (!valid_signal(arg2)) {
1762                                 error = -EINVAL;
1763                                 break;
1764                         }
1765                         current->pdeath_signal = arg2;
1766                         break;
1767                 case PR_GET_PDEATHSIG:
1768                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1769                         break;
1770                 case PR_GET_DUMPABLE:
1771                         error = current->mm->dumpable;
1772                         break;
1773                 case PR_SET_DUMPABLE:
1774                         if (arg2 < 0 || arg2 > 2) {
1775                                 error = -EINVAL;
1776                                 break;
1777                         }
1778                         current->mm->dumpable = arg2;
1779                         break;
1780
1781                 case PR_SET_UNALIGN:
1782                         error = SET_UNALIGN_CTL(current, arg2);
1783                         break;
1784                 case PR_GET_UNALIGN:
1785                         error = GET_UNALIGN_CTL(current, arg2);
1786                         break;
1787                 case PR_SET_FPEMU:
1788                         error = SET_FPEMU_CTL(current, arg2);
1789                         break;
1790                 case PR_GET_FPEMU:
1791                         error = GET_FPEMU_CTL(current, arg2);
1792                         break;
1793                 case PR_SET_FPEXC:
1794                         error = SET_FPEXC_CTL(current, arg2);
1795                         break;
1796                 case PR_GET_FPEXC:
1797                         error = GET_FPEXC_CTL(current, arg2);
1798                         break;
1799                 case PR_GET_TIMING:
1800                         error = PR_TIMING_STATISTICAL;
1801                         break;
1802                 case PR_SET_TIMING:
1803                         if (arg2 == PR_TIMING_STATISTICAL)
1804                                 error = 0;
1805                         else
1806                                 error = -EINVAL;
1807                         break;
1808
1809                 case PR_GET_KEEPCAPS:
1810                         if (current->keep_capabilities)
1811                                 error = 1;
1812                         break;
1813                 case PR_SET_KEEPCAPS:
1814                         if (arg2 != 0 && arg2 != 1) {
1815                                 error = -EINVAL;
1816                                 break;
1817                         }
1818                         current->keep_capabilities = arg2;
1819                         break;
1820                 case PR_SET_NAME: {
1821                         struct task_struct *me = current;
1822                         unsigned char ncomm[sizeof(me->comm)];
1823
1824                         ncomm[sizeof(me->comm)-1] = 0;
1825                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1826                                                 sizeof(me->comm)-1) < 0)
1827                                 return -EFAULT;
1828                         set_task_comm(me, ncomm);
1829                         return 0;
1830                 }
1831                 case PR_GET_NAME: {
1832                         struct task_struct *me = current;
1833                         unsigned char tcomm[sizeof(me->comm)];
1834
1835                         get_task_comm(tcomm, me);
1836                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1837                                 return -EFAULT;
1838                         return 0;
1839                 }
1840                 default:
1841                         error = -EINVAL;
1842                         break;
1843         }
1844         return error;
1845 }