projects/linux·blob v2.6.37-rc7 · refs

1805 lines · 40.9 KiB

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