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