kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart...
[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/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/notifier.h>
12 #include <linux/reboot.h>
13 #include <linux/prctl.h>
14 #include <linux/highuid.h>
15 #include <linux/fs.h>
16 #include <linux/perf_event.h>
17 #include <linux/resource.h>
18 #include <linux/kernel.h>
19 #include <linux/kexec.h>
20 #include <linux/workqueue.h>
21 #include <linux/capability.h>
22 #include <linux/device.h>
23 #include <linux/key.h>
24 #include <linux/times.h>
25 #include <linux/posix-timers.h>
26 #include <linux/security.h>
27 #include <linux/dcookies.h>
28 #include <linux/suspend.h>
29 #include <linux/tty.h>
30 #include <linux/signal.h>
31 #include <linux/cn_proc.h>
32 #include <linux/getcpu.h>
33 #include <linux/task_io_accounting_ops.h>
34 #include <linux/seccomp.h>
35 #include <linux/cpu.h>
36 #include <linux/personality.h>
37 #include <linux/ptrace.h>
38 #include <linux/fs_struct.h>
39 #include <linux/gfp.h>
40
41 #include <linux/compat.h>
42 #include <linux/syscalls.h>
43 #include <linux/kprobes.h>
44 #include <linux/user_namespace.h>
45
46 #include <linux/kmsg_dump.h>
47
48 #include <asm/uaccess.h>
49 #include <asm/io.h>
50 #include <asm/unistd.h>
51
52 #ifndef SET_UNALIGN_CTL
53 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
54 #endif
55 #ifndef GET_UNALIGN_CTL
56 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
57 #endif
58 #ifndef SET_FPEMU_CTL
59 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
60 #endif
61 #ifndef GET_FPEMU_CTL
62 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
63 #endif
64 #ifndef SET_FPEXC_CTL
65 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
66 #endif
67 #ifndef GET_FPEXC_CTL
68 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
69 #endif
70 #ifndef GET_ENDIAN
71 # define GET_ENDIAN(a,b)        (-EINVAL)
72 #endif
73 #ifndef SET_ENDIAN
74 # define SET_ENDIAN(a,b)        (-EINVAL)
75 #endif
76 #ifndef GET_TSC_CTL
77 # define GET_TSC_CTL(a)         (-EINVAL)
78 #endif
79 #ifndef SET_TSC_CTL
80 # define SET_TSC_CTL(a)         (-EINVAL)
81 #endif
82
83 /*
84  * this is where the system-wide overflow UID and GID are defined, for
85  * architectures that now have 32-bit UID/GID but didn't in the past
86  */
87
88 int overflowuid = DEFAULT_OVERFLOWUID;
89 int overflowgid = DEFAULT_OVERFLOWGID;
90
91 #ifdef CONFIG_UID16
92 EXPORT_SYMBOL(overflowuid);
93 EXPORT_SYMBOL(overflowgid);
94 #endif
95
96 /*
97  * the same as above, but for filesystems which can only store a 16-bit
98  * UID and GID. as such, this is needed on all architectures
99  */
100
101 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
102 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
103
104 EXPORT_SYMBOL(fs_overflowuid);
105 EXPORT_SYMBOL(fs_overflowgid);
106
107 /*
108  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
109  */
110
111 int C_A_D = 1;
112 struct pid *cad_pid;
113 EXPORT_SYMBOL(cad_pid);
114
115 /*
116  * If set, this is used for preparing the system to power off.
117  */
118
119 void (*pm_power_off_prepare)(void);
120
121 /*
122  * set the priority of a task
123  * - the caller must hold the RCU read lock
124  */
125 static int set_one_prio(struct task_struct *p, int niceval, int error)
126 {
127         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
128         int no_nice;
129
130         if (pcred->uid  != cred->euid &&
131             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
132                 error = -EPERM;
133                 goto out;
134         }
135         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
136                 error = -EACCES;
137                 goto out;
138         }
139         no_nice = security_task_setnice(p, niceval);
140         if (no_nice) {
141                 error = no_nice;
142                 goto out;
143         }
144         if (error == -ESRCH)
145                 error = 0;
146         set_user_nice(p, niceval);
147 out:
148         return error;
149 }
150
151 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
152 {
153         struct task_struct *g, *p;
154         struct user_struct *user;
155         const struct cred *cred = current_cred();
156         int error = -EINVAL;
157         struct pid *pgrp;
158
159         if (which > PRIO_USER || which < PRIO_PROCESS)
160                 goto out;
161
162         /* normalize: avoid signed division (rounding problems) */
163         error = -ESRCH;
164         if (niceval < -20)
165                 niceval = -20;
166         if (niceval > 19)
167                 niceval = 19;
168
169         rcu_read_lock();
170         read_lock(&tasklist_lock);
171         switch (which) {
172                 case PRIO_PROCESS:
173                         if (who)
174                                 p = find_task_by_vpid(who);
175                         else
176                                 p = current;
177                         if (p)
178                                 error = set_one_prio(p, niceval, error);
179                         break;
180                 case PRIO_PGRP:
181                         if (who)
182                                 pgrp = find_vpid(who);
183                         else
184                                 pgrp = task_pgrp(current);
185                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
186                                 error = set_one_prio(p, niceval, error);
187                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
188                         break;
189                 case PRIO_USER:
190                         user = (struct user_struct *) cred->user;
191                         if (!who)
192                                 who = cred->uid;
193                         else if ((who != cred->uid) &&
194                                  !(user = find_user(who)))
195                                 goto out_unlock;        /* No processes for this user */
196
197                         do_each_thread(g, p) {
198                                 if (__task_cred(p)->uid == who)
199                                         error = set_one_prio(p, niceval, error);
200                         } while_each_thread(g, p);
201                         if (who != cred->uid)
202                                 free_uid(user);         /* For find_user() */
203                         break;
204         }
205 out_unlock:
206         read_unlock(&tasklist_lock);
207         rcu_read_unlock();
208 out:
209         return error;
210 }
211
212 /*
213  * Ugh. To avoid negative return values, "getpriority()" will
214  * not return the normal nice-value, but a negated value that
215  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
216  * to stay compatible.
217  */
218 SYSCALL_DEFINE2(getpriority, int, which, int, who)
219 {
220         struct task_struct *g, *p;
221         struct user_struct *user;
222         const struct cred *cred = current_cred();
223         long niceval, retval = -ESRCH;
224         struct pid *pgrp;
225
226         if (which > PRIO_USER || which < PRIO_PROCESS)
227                 return -EINVAL;
228
229         rcu_read_lock();
230         read_lock(&tasklist_lock);
231         switch (which) {
232                 case PRIO_PROCESS:
233                         if (who)
234                                 p = find_task_by_vpid(who);
235                         else
236                                 p = current;
237                         if (p) {
238                                 niceval = 20 - task_nice(p);
239                                 if (niceval > retval)
240                                         retval = niceval;
241                         }
242                         break;
243                 case PRIO_PGRP:
244                         if (who)
245                                 pgrp = find_vpid(who);
246                         else
247                                 pgrp = task_pgrp(current);
248                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
249                                 niceval = 20 - task_nice(p);
250                                 if (niceval > retval)
251                                         retval = niceval;
252                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
253                         break;
254                 case PRIO_USER:
255                         user = (struct user_struct *) cred->user;
256                         if (!who)
257                                 who = cred->uid;
258                         else if ((who != cred->uid) &&
259                                  !(user = find_user(who)))
260                                 goto out_unlock;        /* No processes for this user */
261
262                         do_each_thread(g, p) {
263                                 if (__task_cred(p)->uid == who) {
264                                         niceval = 20 - task_nice(p);
265                                         if (niceval > retval)
266                                                 retval = niceval;
267                                 }
268                         } while_each_thread(g, p);
269                         if (who != cred->uid)
270                                 free_uid(user);         /* for find_user() */
271                         break;
272         }
273 out_unlock:
274         read_unlock(&tasklist_lock);
275         rcu_read_unlock();
276
277         return retval;
278 }
279
280 /**
281  *      emergency_restart - reboot the system
282  *
283  *      Without shutting down any hardware or taking any locks
284  *      reboot the system.  This is called when we know we are in
285  *      trouble so this is our best effort to reboot.  This is
286  *      safe to call in interrupt context.
287  */
288 void emergency_restart(void)
289 {
290         kmsg_dump(KMSG_DUMP_EMERG);
291         machine_emergency_restart();
292 }
293 EXPORT_SYMBOL_GPL(emergency_restart);
294
295 void kernel_restart_prepare(char *cmd)
296 {
297         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
298         system_state = SYSTEM_RESTART;
299         device_shutdown();
300         sysdev_shutdown();
301 }
302
303 /**
304  *      kernel_restart - reboot the system
305  *      @cmd: pointer to buffer containing command to execute for restart
306  *              or %NULL
307  *
308  *      Shutdown everything and perform a clean reboot.
309  *      This is not safe to call in interrupt context.
310  */
311 void kernel_restart(char *cmd)
312 {
313         kernel_restart_prepare(cmd);
314         if (!cmd)
315                 printk(KERN_EMERG "Restarting system.\n");
316         else
317                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
318         kmsg_dump(KMSG_DUMP_RESTART);
319         machine_restart(cmd);
320 }
321 EXPORT_SYMBOL_GPL(kernel_restart);
322
323 static void kernel_shutdown_prepare(enum system_states state)
324 {
325         blocking_notifier_call_chain(&reboot_notifier_list,
326                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
327         system_state = state;
328         device_shutdown();
329 }
330 /**
331  *      kernel_halt - halt the system
332  *
333  *      Shutdown everything and perform a clean system halt.
334  */
335 void kernel_halt(void)
336 {
337         kernel_shutdown_prepare(SYSTEM_HALT);
338         sysdev_shutdown();
339         printk(KERN_EMERG "System halted.\n");
340         kmsg_dump(KMSG_DUMP_HALT);
341         machine_halt();
342 }
343
344 EXPORT_SYMBOL_GPL(kernel_halt);
345
346 /**
347  *      kernel_power_off - power_off the system
348  *
349  *      Shutdown everything and perform a clean system power_off.
350  */
351 void kernel_power_off(void)
352 {
353         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
354         if (pm_power_off_prepare)
355                 pm_power_off_prepare();
356         disable_nonboot_cpus();
357         sysdev_shutdown();
358         printk(KERN_EMERG "Power down.\n");
359         kmsg_dump(KMSG_DUMP_POWEROFF);
360         machine_power_off();
361 }
362 EXPORT_SYMBOL_GPL(kernel_power_off);
363
364 static DEFINE_MUTEX(reboot_mutex);
365
366 /*
367  * Reboot system call: for obvious reasons only root may call it,
368  * and even root needs to set up some magic numbers in the registers
369  * so that some mistake won't make this reboot the whole machine.
370  * You can also set the meaning of the ctrl-alt-del-key here.
371  *
372  * reboot doesn't sync: do that yourself before calling this.
373  */
374 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
375                 void __user *, arg)
376 {
377         char buffer[256];
378         int ret = 0;
379
380         /* We only trust the superuser with rebooting the system. */
381         if (!capable(CAP_SYS_BOOT))
382                 return -EPERM;
383
384         /* For safety, we require "magic" arguments. */
385         if (magic1 != LINUX_REBOOT_MAGIC1 ||
386             (magic2 != LINUX_REBOOT_MAGIC2 &&
387                         magic2 != LINUX_REBOOT_MAGIC2A &&
388                         magic2 != LINUX_REBOOT_MAGIC2B &&
389                         magic2 != LINUX_REBOOT_MAGIC2C))
390                 return -EINVAL;
391
392         /* Instead of trying to make the power_off code look like
393          * halt when pm_power_off is not set do it the easy way.
394          */
395         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
396                 cmd = LINUX_REBOOT_CMD_HALT;
397
398         mutex_lock(&reboot_mutex);
399         switch (cmd) {
400         case LINUX_REBOOT_CMD_RESTART:
401                 kernel_restart(NULL);
402                 break;
403
404         case LINUX_REBOOT_CMD_CAD_ON:
405                 C_A_D = 1;
406                 break;
407
408         case LINUX_REBOOT_CMD_CAD_OFF:
409                 C_A_D = 0;
410                 break;
411
412         case LINUX_REBOOT_CMD_HALT:
413                 kernel_halt();
414                 do_exit(0);
415                 panic("cannot halt");
416
417         case LINUX_REBOOT_CMD_POWER_OFF:
418                 kernel_power_off();
419                 do_exit(0);
420                 break;
421
422         case LINUX_REBOOT_CMD_RESTART2:
423                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
424                         ret = -EFAULT;
425                         break;
426                 }
427                 buffer[sizeof(buffer) - 1] = '\0';
428
429                 kernel_restart(buffer);
430                 break;
431
432 #ifdef CONFIG_KEXEC
433         case LINUX_REBOOT_CMD_KEXEC:
434                 ret = kernel_kexec();
435                 break;
436 #endif
437
438 #ifdef CONFIG_HIBERNATION
439         case LINUX_REBOOT_CMD_SW_SUSPEND:
440                 ret = hibernate();
441                 break;
442 #endif
443
444         default:
445                 ret = -EINVAL;
446                 break;
447         }
448         mutex_unlock(&reboot_mutex);
449         return ret;
450 }
451
452 static void deferred_cad(struct work_struct *dummy)
453 {
454         kernel_restart(NULL);
455 }
456
457 /*
458  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
459  * As it's called within an interrupt, it may NOT sync: the only choice
460  * is whether to reboot at once, or just ignore the ctrl-alt-del.
461  */
462 void ctrl_alt_del(void)
463 {
464         static DECLARE_WORK(cad_work, deferred_cad);
465
466         if (C_A_D)
467                 schedule_work(&cad_work);
468         else
469                 kill_cad_pid(SIGINT, 1);
470 }
471         
472 /*
473  * Unprivileged users may change the real gid to the effective gid
474  * or vice versa.  (BSD-style)
475  *
476  * If you set the real gid at all, or set the effective gid to a value not
477  * equal to the real gid, then the saved gid is set to the new effective gid.
478  *
479  * This makes it possible for a setgid program to completely drop its
480  * privileges, which is often a useful assertion to make when you are doing
481  * a security audit over a program.
482  *
483  * The general idea is that a program which uses just setregid() will be
484  * 100% compatible with BSD.  A program which uses just setgid() will be
485  * 100% compatible with POSIX with saved IDs. 
486  *
487  * SMP: There are not races, the GIDs are checked only by filesystem
488  *      operations (as far as semantic preservation is concerned).
489  */
490 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
491 {
492         const struct cred *old;
493         struct cred *new;
494         int retval;
495
496         new = prepare_creds();
497         if (!new)
498                 return -ENOMEM;
499         old = current_cred();
500
501         retval = -EPERM;
502         if (rgid != (gid_t) -1) {
503                 if (old->gid == rgid ||
504                     old->egid == rgid ||
505                     capable(CAP_SETGID))
506                         new->gid = rgid;
507                 else
508                         goto error;
509         }
510         if (egid != (gid_t) -1) {
511                 if (old->gid == egid ||
512                     old->egid == egid ||
513                     old->sgid == egid ||
514                     capable(CAP_SETGID))
515                         new->egid = egid;
516                 else
517                         goto error;
518         }
519
520         if (rgid != (gid_t) -1 ||
521             (egid != (gid_t) -1 && egid != old->gid))
522                 new->sgid = new->egid;
523         new->fsgid = new->egid;
524
525         return commit_creds(new);
526
527 error:
528         abort_creds(new);
529         return retval;
530 }
531
532 /*
533  * setgid() is implemented like SysV w/ SAVED_IDS 
534  *
535  * SMP: Same implicit races as above.
536  */
537 SYSCALL_DEFINE1(setgid, gid_t, gid)
538 {
539         const struct cred *old;
540         struct cred *new;
541         int retval;
542
543         new = prepare_creds();
544         if (!new)
545                 return -ENOMEM;
546         old = current_cred();
547
548         retval = -EPERM;
549         if (capable(CAP_SETGID))
550                 new->gid = new->egid = new->sgid = new->fsgid = gid;
551         else if (gid == old->gid || gid == old->sgid)
552                 new->egid = new->fsgid = gid;
553         else
554                 goto error;
555
556         return commit_creds(new);
557
558 error:
559         abort_creds(new);
560         return retval;
561 }
562
563 /*
564  * change the user struct in a credentials set to match the new UID
565  */
566 static int set_user(struct cred *new)
567 {
568         struct user_struct *new_user;
569
570         new_user = alloc_uid(current_user_ns(), new->uid);
571         if (!new_user)
572                 return -EAGAIN;
573
574         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
575                         new_user != INIT_USER) {
576                 free_uid(new_user);
577                 return -EAGAIN;
578         }
579
580         free_uid(new->user);
581         new->user = new_user;
582         return 0;
583 }
584
585 /*
586  * Unprivileged users may change the real uid to the effective uid
587  * or vice versa.  (BSD-style)
588  *
589  * If you set the real uid at all, or set the effective uid to a value not
590  * equal to the real uid, then the saved uid is set to the new effective uid.
591  *
592  * This makes it possible for a setuid program to completely drop its
593  * privileges, which is often a useful assertion to make when you are doing
594  * a security audit over a program.
595  *
596  * The general idea is that a program which uses just setreuid() will be
597  * 100% compatible with BSD.  A program which uses just setuid() will be
598  * 100% compatible with POSIX with saved IDs. 
599  */
600 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
601 {
602         const struct cred *old;
603         struct cred *new;
604         int retval;
605
606         new = prepare_creds();
607         if (!new)
608                 return -ENOMEM;
609         old = current_cred();
610
611         retval = -EPERM;
612         if (ruid != (uid_t) -1) {
613                 new->uid = ruid;
614                 if (old->uid != ruid &&
615                     old->euid != ruid &&
616                     !capable(CAP_SETUID))
617                         goto error;
618         }
619
620         if (euid != (uid_t) -1) {
621                 new->euid = euid;
622                 if (old->uid != euid &&
623                     old->euid != euid &&
624                     old->suid != euid &&
625                     !capable(CAP_SETUID))
626                         goto error;
627         }
628
629         if (new->uid != old->uid) {
630                 retval = set_user(new);
631                 if (retval < 0)
632                         goto error;
633         }
634         if (ruid != (uid_t) -1 ||
635             (euid != (uid_t) -1 && euid != old->uid))
636                 new->suid = new->euid;
637         new->fsuid = new->euid;
638
639         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
640         if (retval < 0)
641                 goto error;
642
643         return commit_creds(new);
644
645 error:
646         abort_creds(new);
647         return retval;
648 }
649                 
650 /*
651  * setuid() is implemented like SysV with SAVED_IDS 
652  * 
653  * Note that SAVED_ID's is deficient in that a setuid root program
654  * like sendmail, for example, cannot set its uid to be a normal 
655  * user and then switch back, because if you're root, setuid() sets
656  * the saved uid too.  If you don't like this, blame the bright people
657  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
658  * will allow a root program to temporarily drop privileges and be able to
659  * regain them by swapping the real and effective uid.  
660  */
661 SYSCALL_DEFINE1(setuid, uid_t, uid)
662 {
663         const struct cred *old;
664         struct cred *new;
665         int retval;
666
667         new = prepare_creds();
668         if (!new)
669                 return -ENOMEM;
670         old = current_cred();
671
672         retval = -EPERM;
673         if (capable(CAP_SETUID)) {
674                 new->suid = new->uid = uid;
675                 if (uid != old->uid) {
676                         retval = set_user(new);
677                         if (retval < 0)
678                                 goto error;
679                 }
680         } else if (uid != old->uid && uid != new->suid) {
681                 goto error;
682         }
683
684         new->fsuid = new->euid = uid;
685
686         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
687         if (retval < 0)
688                 goto error;
689
690         return commit_creds(new);
691
692 error:
693         abort_creds(new);
694         return retval;
695 }
696
697
698 /*
699  * This function implements a generic ability to update ruid, euid,
700  * and suid.  This allows you to implement the 4.4 compatible seteuid().
701  */
702 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
703 {
704         const struct cred *old;
705         struct cred *new;
706         int retval;
707
708         new = prepare_creds();
709         if (!new)
710                 return -ENOMEM;
711
712         old = current_cred();
713
714         retval = -EPERM;
715         if (!capable(CAP_SETUID)) {
716                 if (ruid != (uid_t) -1 && ruid != old->uid &&
717                     ruid != old->euid  && ruid != old->suid)
718                         goto error;
719                 if (euid != (uid_t) -1 && euid != old->uid &&
720                     euid != old->euid  && euid != old->suid)
721                         goto error;
722                 if (suid != (uid_t) -1 && suid != old->uid &&
723                     suid != old->euid  && suid != old->suid)
724                         goto error;
725         }
726
727         if (ruid != (uid_t) -1) {
728                 new->uid = ruid;
729                 if (ruid != old->uid) {
730                         retval = set_user(new);
731                         if (retval < 0)
732                                 goto error;
733                 }
734         }
735         if (euid != (uid_t) -1)
736                 new->euid = euid;
737         if (suid != (uid_t) -1)
738                 new->suid = suid;
739         new->fsuid = new->euid;
740
741         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
742         if (retval < 0)
743                 goto error;
744
745         return commit_creds(new);
746
747 error:
748         abort_creds(new);
749         return retval;
750 }
751
752 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
753 {
754         const struct cred *cred = current_cred();
755         int retval;
756
757         if (!(retval   = put_user(cred->uid,  ruid)) &&
758             !(retval   = put_user(cred->euid, euid)))
759                 retval = put_user(cred->suid, suid);
760
761         return retval;
762 }
763
764 /*
765  * Same as above, but for rgid, egid, sgid.
766  */
767 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
768 {
769         const struct cred *old;
770         struct cred *new;
771         int retval;
772
773         new = prepare_creds();
774         if (!new)
775                 return -ENOMEM;
776         old = current_cred();
777
778         retval = -EPERM;
779         if (!capable(CAP_SETGID)) {
780                 if (rgid != (gid_t) -1 && rgid != old->gid &&
781                     rgid != old->egid  && rgid != old->sgid)
782                         goto error;
783                 if (egid != (gid_t) -1 && egid != old->gid &&
784                     egid != old->egid  && egid != old->sgid)
785                         goto error;
786                 if (sgid != (gid_t) -1 && sgid != old->gid &&
787                     sgid != old->egid  && sgid != old->sgid)
788                         goto error;
789         }
790
791         if (rgid != (gid_t) -1)
792                 new->gid = rgid;
793         if (egid != (gid_t) -1)
794                 new->egid = egid;
795         if (sgid != (gid_t) -1)
796                 new->sgid = sgid;
797         new->fsgid = new->egid;
798
799         return commit_creds(new);
800
801 error:
802         abort_creds(new);
803         return retval;
804 }
805
806 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
807 {
808         const struct cred *cred = current_cred();
809         int retval;
810
811         if (!(retval   = put_user(cred->gid,  rgid)) &&
812             !(retval   = put_user(cred->egid, egid)))
813                 retval = put_user(cred->sgid, sgid);
814
815         return retval;
816 }
817
818
819 /*
820  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
821  * is used for "access()" and for the NFS daemon (letting nfsd stay at
822  * whatever uid it wants to). It normally shadows "euid", except when
823  * explicitly set by setfsuid() or for access..
824  */
825 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
826 {
827         const struct cred *old;
828         struct cred *new;
829         uid_t old_fsuid;
830
831         new = prepare_creds();
832         if (!new)
833                 return current_fsuid();
834         old = current_cred();
835         old_fsuid = old->fsuid;
836
837         if (uid == old->uid  || uid == old->euid  ||
838             uid == old->suid || uid == old->fsuid ||
839             capable(CAP_SETUID)) {
840                 if (uid != old_fsuid) {
841                         new->fsuid = uid;
842                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
843                                 goto change_okay;
844                 }
845         }
846
847         abort_creds(new);
848         return old_fsuid;
849
850 change_okay:
851         commit_creds(new);
852         return old_fsuid;
853 }
854
855 /*
856  * Samma på svenska..
857  */
858 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
859 {
860         const struct cred *old;
861         struct cred *new;
862         gid_t old_fsgid;
863
864         new = prepare_creds();
865         if (!new)
866                 return current_fsgid();
867         old = current_cred();
868         old_fsgid = old->fsgid;
869
870         if (gid == old->gid  || gid == old->egid  ||
871             gid == old->sgid || gid == old->fsgid ||
872             capable(CAP_SETGID)) {
873                 if (gid != old_fsgid) {
874                         new->fsgid = gid;
875                         goto change_okay;
876                 }
877         }
878
879         abort_creds(new);
880         return old_fsgid;
881
882 change_okay:
883         commit_creds(new);
884         return old_fsgid;
885 }
886
887 void do_sys_times(struct tms *tms)
888 {
889         cputime_t tgutime, tgstime, cutime, cstime;
890
891         spin_lock_irq(&current->sighand->siglock);
892         thread_group_times(current, &tgutime, &tgstime);
893         cutime = current->signal->cutime;
894         cstime = current->signal->cstime;
895         spin_unlock_irq(&current->sighand->siglock);
896         tms->tms_utime = cputime_to_clock_t(tgutime);
897         tms->tms_stime = cputime_to_clock_t(tgstime);
898         tms->tms_cutime = cputime_to_clock_t(cutime);
899         tms->tms_cstime = cputime_to_clock_t(cstime);
900 }
901
902 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
903 {
904         if (tbuf) {
905                 struct tms tmp;
906
907                 do_sys_times(&tmp);
908                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
909                         return -EFAULT;
910         }
911         force_successful_syscall_return();
912         return (long) jiffies_64_to_clock_t(get_jiffies_64());
913 }
914
915 /*
916  * This needs some heavy checking ...
917  * I just haven't the stomach for it. I also don't fully
918  * understand sessions/pgrp etc. Let somebody who does explain it.
919  *
920  * OK, I think I have the protection semantics right.... this is really
921  * only important on a multi-user system anyway, to make sure one user
922  * can't send a signal to a process owned by another.  -TYT, 12/12/91
923  *
924  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
925  * LBT 04.03.94
926  */
927 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
928 {
929         struct task_struct *p;
930         struct task_struct *group_leader = current->group_leader;
931         struct pid *pgrp;
932         int err;
933
934         if (!pid)
935                 pid = task_pid_vnr(group_leader);
936         if (!pgid)
937                 pgid = pid;
938         if (pgid < 0)
939                 return -EINVAL;
940         rcu_read_lock();
941
942         /* From this point forward we keep holding onto the tasklist lock
943          * so that our parent does not change from under us. -DaveM
944          */
945         write_lock_irq(&tasklist_lock);
946
947         err = -ESRCH;
948         p = find_task_by_vpid(pid);
949         if (!p)
950                 goto out;
951
952         err = -EINVAL;
953         if (!thread_group_leader(p))
954                 goto out;
955
956         if (same_thread_group(p->real_parent, group_leader)) {
957                 err = -EPERM;
958                 if (task_session(p) != task_session(group_leader))
959                         goto out;
960                 err = -EACCES;
961                 if (p->did_exec)
962                         goto out;
963         } else {
964                 err = -ESRCH;
965                 if (p != group_leader)
966                         goto out;
967         }
968
969         err = -EPERM;
970         if (p->signal->leader)
971                 goto out;
972
973         pgrp = task_pid(p);
974         if (pgid != pid) {
975                 struct task_struct *g;
976
977                 pgrp = find_vpid(pgid);
978                 g = pid_task(pgrp, PIDTYPE_PGID);
979                 if (!g || task_session(g) != task_session(group_leader))
980                         goto out;
981         }
982
983         err = security_task_setpgid(p, pgid);
984         if (err)
985                 goto out;
986
987         if (task_pgrp(p) != pgrp)
988                 change_pid(p, PIDTYPE_PGID, pgrp);
989
990         err = 0;
991 out:
992         /* All paths lead to here, thus we are safe. -DaveM */
993         write_unlock_irq(&tasklist_lock);
994         rcu_read_unlock();
995         return err;
996 }
997
998 SYSCALL_DEFINE1(getpgid, pid_t, pid)
999 {
1000         struct task_struct *p;
1001         struct pid *grp;
1002         int retval;
1003
1004         rcu_read_lock();
1005         if (!pid)
1006                 grp = task_pgrp(current);
1007         else {
1008                 retval = -ESRCH;
1009                 p = find_task_by_vpid(pid);
1010                 if (!p)
1011                         goto out;
1012                 grp = task_pgrp(p);
1013                 if (!grp)
1014                         goto out;
1015
1016                 retval = security_task_getpgid(p);
1017                 if (retval)
1018                         goto out;
1019         }
1020         retval = pid_vnr(grp);
1021 out:
1022         rcu_read_unlock();
1023         return retval;
1024 }
1025
1026 #ifdef __ARCH_WANT_SYS_GETPGRP
1027
1028 SYSCALL_DEFINE0(getpgrp)
1029 {
1030         return sys_getpgid(0);
1031 }
1032
1033 #endif
1034
1035 SYSCALL_DEFINE1(getsid, pid_t, pid)
1036 {
1037         struct task_struct *p;
1038         struct pid *sid;
1039         int retval;
1040
1041         rcu_read_lock();
1042         if (!pid)
1043                 sid = task_session(current);
1044         else {
1045                 retval = -ESRCH;
1046                 p = find_task_by_vpid(pid);
1047                 if (!p)
1048                         goto out;
1049                 sid = task_session(p);
1050                 if (!sid)
1051                         goto out;
1052
1053                 retval = security_task_getsid(p);
1054                 if (retval)
1055                         goto out;
1056         }
1057         retval = pid_vnr(sid);
1058 out:
1059         rcu_read_unlock();
1060         return retval;
1061 }
1062
1063 SYSCALL_DEFINE0(setsid)
1064 {
1065         struct task_struct *group_leader = current->group_leader;
1066         struct pid *sid = task_pid(group_leader);
1067         pid_t session = pid_vnr(sid);
1068         int err = -EPERM;
1069
1070         write_lock_irq(&tasklist_lock);
1071         /* Fail if I am already a session leader */
1072         if (group_leader->signal->leader)
1073                 goto out;
1074
1075         /* Fail if a process group id already exists that equals the
1076          * proposed session id.
1077          */
1078         if (pid_task(sid, PIDTYPE_PGID))
1079                 goto out;
1080
1081         group_leader->signal->leader = 1;
1082         __set_special_pids(sid);
1083
1084         proc_clear_tty(group_leader);
1085
1086         err = session;
1087 out:
1088         write_unlock_irq(&tasklist_lock);
1089         if (err > 0) {
1090                 proc_sid_connector(group_leader);
1091                 sched_autogroup_create_attach(group_leader);
1092         }
1093         return err;
1094 }
1095
1096 DECLARE_RWSEM(uts_sem);
1097
1098 #ifdef COMPAT_UTS_MACHINE
1099 #define override_architecture(name) \
1100         (personality(current->personality) == PER_LINUX32 && \
1101          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1102                       sizeof(COMPAT_UTS_MACHINE)))
1103 #else
1104 #define override_architecture(name)     0
1105 #endif
1106
1107 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1108 {
1109         int errno = 0;
1110
1111         down_read(&uts_sem);
1112         if (copy_to_user(name, utsname(), sizeof *name))
1113                 errno = -EFAULT;
1114         up_read(&uts_sem);
1115
1116         if (!errno && override_architecture(name))
1117                 errno = -EFAULT;
1118         return errno;
1119 }
1120
1121 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1122 /*
1123  * Old cruft
1124  */
1125 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1126 {
1127         int error = 0;
1128
1129         if (!name)
1130                 return -EFAULT;
1131
1132         down_read(&uts_sem);
1133         if (copy_to_user(name, utsname(), sizeof(*name)))
1134                 error = -EFAULT;
1135         up_read(&uts_sem);
1136
1137         if (!error && override_architecture(name))
1138                 error = -EFAULT;
1139         return error;
1140 }
1141
1142 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1143 {
1144         int error;
1145
1146         if (!name)
1147                 return -EFAULT;
1148         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1149                 return -EFAULT;
1150
1151         down_read(&uts_sem);
1152         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1153                                __OLD_UTS_LEN);
1154         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1155         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1156                                 __OLD_UTS_LEN);
1157         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1158         error |= __copy_to_user(&name->release, &utsname()->release,
1159                                 __OLD_UTS_LEN);
1160         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1161         error |= __copy_to_user(&name->version, &utsname()->version,
1162                                 __OLD_UTS_LEN);
1163         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1164         error |= __copy_to_user(&name->machine, &utsname()->machine,
1165                                 __OLD_UTS_LEN);
1166         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1167         up_read(&uts_sem);
1168
1169         if (!error && override_architecture(name))
1170                 error = -EFAULT;
1171         return error ? -EFAULT : 0;
1172 }
1173 #endif
1174
1175 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1176 {
1177         int errno;
1178         char tmp[__NEW_UTS_LEN];
1179
1180         if (!capable(CAP_SYS_ADMIN))
1181                 return -EPERM;
1182         if (len < 0 || len > __NEW_UTS_LEN)
1183                 return -EINVAL;
1184         down_write(&uts_sem);
1185         errno = -EFAULT;
1186         if (!copy_from_user(tmp, name, len)) {
1187                 struct new_utsname *u = utsname();
1188
1189                 memcpy(u->nodename, tmp, len);
1190                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1191                 errno = 0;
1192         }
1193         up_write(&uts_sem);
1194         return errno;
1195 }
1196
1197 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1198
1199 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1200 {
1201         int i, errno;
1202         struct new_utsname *u;
1203
1204         if (len < 0)
1205                 return -EINVAL;
1206         down_read(&uts_sem);
1207         u = utsname();
1208         i = 1 + strlen(u->nodename);
1209         if (i > len)
1210                 i = len;
1211         errno = 0;
1212         if (copy_to_user(name, u->nodename, i))
1213                 errno = -EFAULT;
1214         up_read(&uts_sem);
1215         return errno;
1216 }
1217
1218 #endif
1219
1220 /*
1221  * Only setdomainname; getdomainname can be implemented by calling
1222  * uname()
1223  */
1224 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1225 {
1226         int errno;
1227         char tmp[__NEW_UTS_LEN];
1228
1229         if (!capable(CAP_SYS_ADMIN))
1230                 return -EPERM;
1231         if (len < 0 || len > __NEW_UTS_LEN)
1232                 return -EINVAL;
1233
1234         down_write(&uts_sem);
1235         errno = -EFAULT;
1236         if (!copy_from_user(tmp, name, len)) {
1237                 struct new_utsname *u = utsname();
1238
1239                 memcpy(u->domainname, tmp, len);
1240                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1241                 errno = 0;
1242         }
1243         up_write(&uts_sem);
1244         return errno;
1245 }
1246
1247 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1248 {
1249         struct rlimit value;
1250         int ret;
1251
1252         ret = do_prlimit(current, resource, NULL, &value);
1253         if (!ret)
1254                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1255
1256         return ret;
1257 }
1258
1259 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1260
1261 /*
1262  *      Back compatibility for getrlimit. Needed for some apps.
1263  */
1264  
1265 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1266                 struct rlimit __user *, rlim)
1267 {
1268         struct rlimit x;
1269         if (resource >= RLIM_NLIMITS)
1270                 return -EINVAL;
1271
1272         task_lock(current->group_leader);
1273         x = current->signal->rlim[resource];
1274         task_unlock(current->group_leader);
1275         if (x.rlim_cur > 0x7FFFFFFF)
1276                 x.rlim_cur = 0x7FFFFFFF;
1277         if (x.rlim_max > 0x7FFFFFFF)
1278                 x.rlim_max = 0x7FFFFFFF;
1279         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1280 }
1281
1282 #endif
1283
1284 static inline bool rlim64_is_infinity(__u64 rlim64)
1285 {
1286 #if BITS_PER_LONG < 64
1287         return rlim64 >= ULONG_MAX;
1288 #else
1289         return rlim64 == RLIM64_INFINITY;
1290 #endif
1291 }
1292
1293 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1294 {
1295         if (rlim->rlim_cur == RLIM_INFINITY)
1296                 rlim64->rlim_cur = RLIM64_INFINITY;
1297         else
1298                 rlim64->rlim_cur = rlim->rlim_cur;
1299         if (rlim->rlim_max == RLIM_INFINITY)
1300                 rlim64->rlim_max = RLIM64_INFINITY;
1301         else
1302                 rlim64->rlim_max = rlim->rlim_max;
1303 }
1304
1305 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1306 {
1307         if (rlim64_is_infinity(rlim64->rlim_cur))
1308                 rlim->rlim_cur = RLIM_INFINITY;
1309         else
1310                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1311         if (rlim64_is_infinity(rlim64->rlim_max))
1312                 rlim->rlim_max = RLIM_INFINITY;
1313         else
1314                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1315 }
1316
1317 /* make sure you are allowed to change @tsk limits before calling this */
1318 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1319                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1320 {
1321         struct rlimit *rlim;
1322         int retval = 0;
1323
1324         if (resource >= RLIM_NLIMITS)
1325                 return -EINVAL;
1326         if (new_rlim) {
1327                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1328                         return -EINVAL;
1329                 if (resource == RLIMIT_NOFILE &&
1330                                 new_rlim->rlim_max > sysctl_nr_open)
1331                         return -EPERM;
1332         }
1333
1334         /* protect tsk->signal and tsk->sighand from disappearing */
1335         read_lock(&tasklist_lock);
1336         if (!tsk->sighand) {
1337                 retval = -ESRCH;
1338                 goto out;
1339         }
1340
1341         rlim = tsk->signal->rlim + resource;
1342         task_lock(tsk->group_leader);
1343         if (new_rlim) {
1344                 if (new_rlim->rlim_max > rlim->rlim_max &&
1345                                 !capable(CAP_SYS_RESOURCE))
1346                         retval = -EPERM;
1347                 if (!retval)
1348                         retval = security_task_setrlimit(tsk->group_leader,
1349                                         resource, new_rlim);
1350                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1351                         /*
1352                          * The caller is asking for an immediate RLIMIT_CPU
1353                          * expiry.  But we use the zero value to mean "it was
1354                          * never set".  So let's cheat and make it one second
1355                          * instead
1356                          */
1357                         new_rlim->rlim_cur = 1;
1358                 }
1359         }
1360         if (!retval) {
1361                 if (old_rlim)
1362                         *old_rlim = *rlim;
1363                 if (new_rlim)
1364                         *rlim = *new_rlim;
1365         }
1366         task_unlock(tsk->group_leader);
1367
1368         /*
1369          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1370          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1371          * very long-standing error, and fixing it now risks breakage of
1372          * applications, so we live with it
1373          */
1374          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1375                          new_rlim->rlim_cur != RLIM_INFINITY)
1376                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1377 out:
1378         read_unlock(&tasklist_lock);
1379         return retval;
1380 }
1381
1382 /* rcu lock must be held */
1383 static int check_prlimit_permission(struct task_struct *task)
1384 {
1385         const struct cred *cred = current_cred(), *tcred;
1386
1387         tcred = __task_cred(task);
1388         if ((cred->uid != tcred->euid ||
1389              cred->uid != tcred->suid ||
1390              cred->uid != tcred->uid  ||
1391              cred->gid != tcred->egid ||
1392              cred->gid != tcred->sgid ||
1393              cred->gid != tcred->gid) &&
1394              !capable(CAP_SYS_RESOURCE)) {
1395                 return -EPERM;
1396         }
1397
1398         return 0;
1399 }
1400
1401 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1402                 const struct rlimit64 __user *, new_rlim,
1403                 struct rlimit64 __user *, old_rlim)
1404 {
1405         struct rlimit64 old64, new64;
1406         struct rlimit old, new;
1407         struct task_struct *tsk;
1408         int ret;
1409
1410         if (new_rlim) {
1411                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1412                         return -EFAULT;
1413                 rlim64_to_rlim(&new64, &new);
1414         }
1415
1416         rcu_read_lock();
1417         tsk = pid ? find_task_by_vpid(pid) : current;
1418         if (!tsk) {
1419                 rcu_read_unlock();
1420                 return -ESRCH;
1421         }
1422         ret = check_prlimit_permission(tsk);
1423         if (ret) {
1424                 rcu_read_unlock();
1425                 return ret;
1426         }
1427         get_task_struct(tsk);
1428         rcu_read_unlock();
1429
1430         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1431                         old_rlim ? &old : NULL);
1432
1433         if (!ret && old_rlim) {
1434                 rlim_to_rlim64(&old, &old64);
1435                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1436                         ret = -EFAULT;
1437         }
1438
1439         put_task_struct(tsk);
1440         return ret;
1441 }
1442
1443 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1444 {
1445         struct rlimit new_rlim;
1446
1447         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1448                 return -EFAULT;
1449         return do_prlimit(current, resource, &new_rlim, NULL);
1450 }
1451
1452 /*
1453  * It would make sense to put struct rusage in the task_struct,
1454  * except that would make the task_struct be *really big*.  After
1455  * task_struct gets moved into malloc'ed memory, it would
1456  * make sense to do this.  It will make moving the rest of the information
1457  * a lot simpler!  (Which we're not doing right now because we're not
1458  * measuring them yet).
1459  *
1460  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1461  * races with threads incrementing their own counters.  But since word
1462  * reads are atomic, we either get new values or old values and we don't
1463  * care which for the sums.  We always take the siglock to protect reading
1464  * the c* fields from p->signal from races with exit.c updating those
1465  * fields when reaping, so a sample either gets all the additions of a
1466  * given child after it's reaped, or none so this sample is before reaping.
1467  *
1468  * Locking:
1469  * We need to take the siglock for CHILDEREN, SELF and BOTH
1470  * for  the cases current multithreaded, non-current single threaded
1471  * non-current multithreaded.  Thread traversal is now safe with
1472  * the siglock held.
1473  * Strictly speaking, we donot need to take the siglock if we are current and
1474  * single threaded,  as no one else can take our signal_struct away, no one
1475  * else can  reap the  children to update signal->c* counters, and no one else
1476  * can race with the signal-> fields. If we do not take any lock, the
1477  * signal-> fields could be read out of order while another thread was just
1478  * exiting. So we should  place a read memory barrier when we avoid the lock.
1479  * On the writer side,  write memory barrier is implied in  __exit_signal
1480  * as __exit_signal releases  the siglock spinlock after updating the signal->
1481  * fields. But we don't do this yet to keep things simple.
1482  *
1483  */
1484
1485 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1486 {
1487         r->ru_nvcsw += t->nvcsw;
1488         r->ru_nivcsw += t->nivcsw;
1489         r->ru_minflt += t->min_flt;
1490         r->ru_majflt += t->maj_flt;
1491         r->ru_inblock += task_io_get_inblock(t);
1492         r->ru_oublock += task_io_get_oublock(t);
1493 }
1494
1495 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1496 {
1497         struct task_struct *t;
1498         unsigned long flags;
1499         cputime_t tgutime, tgstime, utime, stime;
1500         unsigned long maxrss = 0;
1501
1502         memset((char *) r, 0, sizeof *r);
1503         utime = stime = cputime_zero;
1504
1505         if (who == RUSAGE_THREAD) {
1506                 task_times(current, &utime, &stime);
1507                 accumulate_thread_rusage(p, r);
1508                 maxrss = p->signal->maxrss;
1509                 goto out;
1510         }
1511
1512         if (!lock_task_sighand(p, &flags))
1513                 return;
1514
1515         switch (who) {
1516                 case RUSAGE_BOTH:
1517                 case RUSAGE_CHILDREN:
1518                         utime = p->signal->cutime;
1519                         stime = p->signal->cstime;
1520                         r->ru_nvcsw = p->signal->cnvcsw;
1521                         r->ru_nivcsw = p->signal->cnivcsw;
1522                         r->ru_minflt = p->signal->cmin_flt;
1523                         r->ru_majflt = p->signal->cmaj_flt;
1524                         r->ru_inblock = p->signal->cinblock;
1525                         r->ru_oublock = p->signal->coublock;
1526                         maxrss = p->signal->cmaxrss;
1527
1528                         if (who == RUSAGE_CHILDREN)
1529                                 break;
1530
1531                 case RUSAGE_SELF:
1532                         thread_group_times(p, &tgutime, &tgstime);
1533                         utime = cputime_add(utime, tgutime);
1534                         stime = cputime_add(stime, tgstime);
1535                         r->ru_nvcsw += p->signal->nvcsw;
1536                         r->ru_nivcsw += p->signal->nivcsw;
1537                         r->ru_minflt += p->signal->min_flt;
1538                         r->ru_majflt += p->signal->maj_flt;
1539                         r->ru_inblock += p->signal->inblock;
1540                         r->ru_oublock += p->signal->oublock;
1541                         if (maxrss < p->signal->maxrss)
1542                                 maxrss = p->signal->maxrss;
1543                         t = p;
1544                         do {
1545                                 accumulate_thread_rusage(t, r);
1546                                 t = next_thread(t);
1547                         } while (t != p);
1548                         break;
1549
1550                 default:
1551                         BUG();
1552         }
1553         unlock_task_sighand(p, &flags);
1554
1555 out:
1556         cputime_to_timeval(utime, &r->ru_utime);
1557         cputime_to_timeval(stime, &r->ru_stime);
1558
1559         if (who != RUSAGE_CHILDREN) {
1560                 struct mm_struct *mm = get_task_mm(p);
1561                 if (mm) {
1562                         setmax_mm_hiwater_rss(&maxrss, mm);
1563                         mmput(mm);
1564                 }
1565         }
1566         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1567 }
1568
1569 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1570 {
1571         struct rusage r;
1572         k_getrusage(p, who, &r);
1573         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1574 }
1575
1576 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1577 {
1578         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1579             who != RUSAGE_THREAD)
1580                 return -EINVAL;
1581         return getrusage(current, who, ru);
1582 }
1583
1584 SYSCALL_DEFINE1(umask, int, mask)
1585 {
1586         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1587         return mask;
1588 }
1589
1590 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1591                 unsigned long, arg4, unsigned long, arg5)
1592 {
1593         struct task_struct *me = current;
1594         unsigned char comm[sizeof(me->comm)];
1595         long error;
1596
1597         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1598         if (error != -ENOSYS)
1599                 return error;
1600
1601         error = 0;
1602         switch (option) {
1603                 case PR_SET_PDEATHSIG:
1604                         if (!valid_signal(arg2)) {
1605                                 error = -EINVAL;
1606                                 break;
1607                         }
1608                         me->pdeath_signal = arg2;
1609                         error = 0;
1610                         break;
1611                 case PR_GET_PDEATHSIG:
1612                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1613                         break;
1614                 case PR_GET_DUMPABLE:
1615                         error = get_dumpable(me->mm);
1616                         break;
1617                 case PR_SET_DUMPABLE:
1618                         if (arg2 < 0 || arg2 > 1) {
1619                                 error = -EINVAL;
1620                                 break;
1621                         }
1622                         set_dumpable(me->mm, arg2);
1623                         error = 0;
1624                         break;
1625
1626                 case PR_SET_UNALIGN:
1627                         error = SET_UNALIGN_CTL(me, arg2);
1628                         break;
1629                 case PR_GET_UNALIGN:
1630                         error = GET_UNALIGN_CTL(me, arg2);
1631                         break;
1632                 case PR_SET_FPEMU:
1633                         error = SET_FPEMU_CTL(me, arg2);
1634                         break;
1635                 case PR_GET_FPEMU:
1636                         error = GET_FPEMU_CTL(me, arg2);
1637                         break;
1638                 case PR_SET_FPEXC:
1639                         error = SET_FPEXC_CTL(me, arg2);
1640                         break;
1641                 case PR_GET_FPEXC:
1642                         error = GET_FPEXC_CTL(me, arg2);
1643                         break;
1644                 case PR_GET_TIMING:
1645                         error = PR_TIMING_STATISTICAL;
1646                         break;
1647                 case PR_SET_TIMING:
1648                         if (arg2 != PR_TIMING_STATISTICAL)
1649                                 error = -EINVAL;
1650                         else
1651                                 error = 0;
1652                         break;
1653
1654                 case PR_SET_NAME:
1655                         comm[sizeof(me->comm)-1] = 0;
1656                         if (strncpy_from_user(comm, (char __user *)arg2,
1657                                               sizeof(me->comm) - 1) < 0)
1658                                 return -EFAULT;
1659                         set_task_comm(me, comm);
1660                         return 0;
1661                 case PR_GET_NAME:
1662                         get_task_comm(comm, me);
1663                         if (copy_to_user((char __user *)arg2, comm,
1664                                          sizeof(comm)))
1665                                 return -EFAULT;
1666                         return 0;
1667                 case PR_GET_ENDIAN:
1668                         error = GET_ENDIAN(me, arg2);
1669                         break;
1670                 case PR_SET_ENDIAN:
1671                         error = SET_ENDIAN(me, arg2);
1672                         break;
1673
1674                 case PR_GET_SECCOMP:
1675                         error = prctl_get_seccomp();
1676                         break;
1677                 case PR_SET_SECCOMP:
1678                         error = prctl_set_seccomp(arg2);
1679                         break;
1680                 case PR_GET_TSC:
1681                         error = GET_TSC_CTL(arg2);
1682                         break;
1683                 case PR_SET_TSC:
1684                         error = SET_TSC_CTL(arg2);
1685                         break;
1686                 case PR_TASK_PERF_EVENTS_DISABLE:
1687                         error = perf_event_task_disable();
1688                         break;
1689                 case PR_TASK_PERF_EVENTS_ENABLE:
1690                         error = perf_event_task_enable();
1691                         break;
1692                 case PR_GET_TIMERSLACK:
1693                         error = current->timer_slack_ns;
1694                         break;
1695                 case PR_SET_TIMERSLACK:
1696                         if (arg2 <= 0)
1697                                 current->timer_slack_ns =
1698                                         current->default_timer_slack_ns;
1699                         else
1700                                 current->timer_slack_ns = arg2;
1701                         error = 0;
1702                         break;
1703                 case PR_MCE_KILL:
1704                         if (arg4 | arg5)
1705                                 return -EINVAL;
1706                         switch (arg2) {
1707                         case PR_MCE_KILL_CLEAR:
1708                                 if (arg3 != 0)
1709                                         return -EINVAL;
1710                                 current->flags &= ~PF_MCE_PROCESS;
1711                                 break;
1712                         case PR_MCE_KILL_SET:
1713                                 current->flags |= PF_MCE_PROCESS;
1714                                 if (arg3 == PR_MCE_KILL_EARLY)
1715                                         current->flags |= PF_MCE_EARLY;
1716                                 else if (arg3 == PR_MCE_KILL_LATE)
1717                                         current->flags &= ~PF_MCE_EARLY;
1718                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1719                                         current->flags &=
1720                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1721                                 else
1722                                         return -EINVAL;
1723                                 break;
1724                         default:
1725                                 return -EINVAL;
1726                         }
1727                         error = 0;
1728                         break;
1729                 case PR_MCE_KILL_GET:
1730                         if (arg2 | arg3 | arg4 | arg5)
1731                                 return -EINVAL;
1732                         if (current->flags & PF_MCE_PROCESS)
1733                                 error = (current->flags & PF_MCE_EARLY) ?
1734                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1735                         else
1736                                 error = PR_MCE_KILL_DEFAULT;
1737                         break;
1738                 default:
1739                         error = -EINVAL;
1740                         break;
1741         }
1742         return error;
1743 }
1744
1745 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1746                 struct getcpu_cache __user *, unused)
1747 {
1748         int err = 0;
1749         int cpu = raw_smp_processor_id();
1750         if (cpup)
1751                 err |= put_user(cpu, cpup);
1752         if (nodep)
1753                 err |= put_user(cpu_to_node(cpu), nodep);
1754         return err ? -EFAULT : 0;
1755 }
1756
1757 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1758
1759 static void argv_cleanup(struct subprocess_info *info)
1760 {
1761         argv_free(info->argv);
1762 }
1763
1764 /**
1765  * orderly_poweroff - Trigger an orderly system poweroff
1766  * @force: force poweroff if command execution fails
1767  *
1768  * This may be called from any context to trigger a system shutdown.
1769  * If the orderly shutdown fails, it will force an immediate shutdown.
1770  */
1771 int orderly_poweroff(bool force)
1772 {
1773         int argc;
1774         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1775         static char *envp[] = {
1776                 "HOME=/",
1777                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1778                 NULL
1779         };
1780         int ret = -ENOMEM;
1781         struct subprocess_info *info;
1782
1783         if (argv == NULL) {
1784                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1785                        __func__, poweroff_cmd);
1786                 goto out;
1787         }
1788
1789         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1790         if (info == NULL) {
1791                 argv_free(argv);
1792                 goto out;
1793         }
1794
1795         call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1796
1797         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1798
1799   out:
1800         if (ret && force) {
1801                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1802                        "forcing the issue\n");
1803
1804                 /* I guess this should try to kick off some daemon to
1805                    sync and poweroff asap.  Or not even bother syncing
1806                    if we're doing an emergency shutdown? */
1807                 emergency_sync();
1808                 kernel_power_off();
1809         }
1810
1811         return ret;
1812 }
1813 EXPORT_SYMBOL_GPL(orderly_poweroff);