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xen/blkback: potential null dereference in error handling
[linux-2.6.git] / kernel / sys.c
blobe4128b278f2375dc4e91c7244fbb4117b5230fea
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 #include <linux/syscore_ops.h>
41
42 #include <linux/compat.h>
43 #include <linux/syscalls.h>
44 #include <linux/kprobes.h>
45 #include <linux/user_namespace.h>
46
47 #include <linux/kmsg_dump.h>
48
49 #include <asm/uaccess.h>
50 #include <asm/io.h>
51 #include <asm/unistd.h>
52
53 #ifndef SET_UNALIGN_CTL
54 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
55 #endif
56 #ifndef GET_UNALIGN_CTL
57 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
58 #endif
59 #ifndef SET_FPEMU_CTL
60 # define SET_FPEMU_CTL(a,b) (-EINVAL)
61 #endif
62 #ifndef GET_FPEMU_CTL
63 # define GET_FPEMU_CTL(a,b) (-EINVAL)
64 #endif
65 #ifndef SET_FPEXC_CTL
66 # define SET_FPEXC_CTL(a,b) (-EINVAL)
67 #endif
68 #ifndef GET_FPEXC_CTL
69 # define GET_FPEXC_CTL(a,b) (-EINVAL)
70 #endif
71 #ifndef GET_ENDIAN
72 # define GET_ENDIAN(a,b) (-EINVAL)
73 #endif
74 #ifndef SET_ENDIAN
75 # define SET_ENDIAN(a,b) (-EINVAL)
76 #endif
77 #ifndef GET_TSC_CTL
78 # define GET_TSC_CTL(a) (-EINVAL)
79 #endif
80 #ifndef SET_TSC_CTL
81 # define SET_TSC_CTL(a) (-EINVAL)
82 #endif
83
84 /*
85 * this is where the system-wide overflow UID and GID are defined, for
86 * architectures that now have 32-bit UID/GID but didn't in the past
87 */
88
89 int overflowuid = DEFAULT_OVERFLOWUID;
90 int overflowgid = DEFAULT_OVERFLOWGID;
91
92 #ifdef CONFIG_UID16
93 EXPORT_SYMBOL(overflowuid);
94 EXPORT_SYMBOL(overflowgid);
95 #endif
96
97 /*
98 * the same as above, but for filesystems which can only store a 16-bit
99 * UID and GID. as such, this is needed on all architectures
100 */
101
102 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
103 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
104
105 EXPORT_SYMBOL(fs_overflowuid);
106 EXPORT_SYMBOL(fs_overflowgid);
107
108 /*
109 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
110 */
111
112 int C_A_D = 1;
113 struct pid *cad_pid;
114 EXPORT_SYMBOL(cad_pid);
115
116 /*
117 * If set, this is used for preparing the system to power off.
118 */
119
120 void (*pm_power_off_prepare)(void);
121
122 /*
123 * Returns true if current's euid is same as p's uid or euid,
124 * or has CAP_SYS_NICE to p's user_ns.
125 *
126 * Called with rcu_read_lock, creds are safe
127 */
128 static bool set_one_prio_perm(struct task_struct *p)
129 {
130 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
131
132 if (pcred->user->user_ns == cred->user->user_ns &&
133 (pcred->uid == cred->euid ||
134 pcred->euid == cred->euid))
135 return true;
136 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
137 return true;
138 return false;
139 }
140
141 /*
142 * set the priority of a task
143 * - the caller must hold the RCU read lock
144 */
145 static int set_one_prio(struct task_struct *p, int niceval, int error)
146 {
147 int no_nice;
148
149 if (!set_one_prio_perm(p)) {
150 error = -EPERM;
151 goto out;
152 }
153 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
154 error = -EACCES;
155 goto out;
156 }
157 no_nice = security_task_setnice(p, niceval);
158 if (no_nice) {
159 error = no_nice;
160 goto out;
161 }
162 if (error == -ESRCH)
163 error = 0;
164 set_user_nice(p, niceval);
165 out:
166 return error;
167 }
168
169 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
170 {
171 struct task_struct *g, *p;
172 struct user_struct *user;
173 const struct cred *cred = current_cred();
174 int error = -EINVAL;
175 struct pid *pgrp;
176
177 if (which > PRIO_USER || which < PRIO_PROCESS)
178 goto out;
179
180 /* normalize: avoid signed division (rounding problems) */
181 error = -ESRCH;
182 if (niceval < -20)
183 niceval = -20;
184 if (niceval > 19)
185 niceval = 19;
186
187 rcu_read_lock();
188 read_lock(&tasklist_lock);
189 switch (which) {
190 case PRIO_PROCESS:
191 if (who)
192 p = find_task_by_vpid(who);
193 else
194 p = current;
195 if (p)
196 error = set_one_prio(p, niceval, error);
197 break;
198 case PRIO_PGRP:
199 if (who)
200 pgrp = find_vpid(who);
201 else
202 pgrp = task_pgrp(current);
203 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
204 error = set_one_prio(p, niceval, error);
205 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
206 break;
207 case PRIO_USER:
208 user = (struct user_struct *) cred->user;
209 if (!who)
210 who = cred->uid;
211 else if ((who != cred->uid) &&
212 !(user = find_user(who)))
213 goto out_unlock; /* No processes for this user */
214
215 do_each_thread(g, p) {
216 if (__task_cred(p)->uid == who)
217 error = set_one_prio(p, niceval, error);
218 } while_each_thread(g, p);
219 if (who != cred->uid)
220 free_uid(user); /* For find_user() */
221 break;
222 }
223 out_unlock:
224 read_unlock(&tasklist_lock);
225 rcu_read_unlock();
226 out:
227 return error;
228 }
229
230 /*
231 * Ugh. To avoid negative return values, "getpriority()" will
232 * not return the normal nice-value, but a negated value that
233 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
234 * to stay compatible.
235 */
236 SYSCALL_DEFINE2(getpriority, int, which, int, who)
237 {
238 struct task_struct *g, *p;
239 struct user_struct *user;
240 const struct cred *cred = current_cred();
241 long niceval, retval = -ESRCH;
242 struct pid *pgrp;
243
244 if (which > PRIO_USER || which < PRIO_PROCESS)
245 return -EINVAL;
246
247 rcu_read_lock();
248 read_lock(&tasklist_lock);
249 switch (which) {
250 case PRIO_PROCESS:
251 if (who)
252 p = find_task_by_vpid(who);
253 else
254 p = current;
255 if (p) {
256 niceval = 20 - task_nice(p);
257 if (niceval > retval)
258 retval = niceval;
259 }
260 break;
261 case PRIO_PGRP:
262 if (who)
263 pgrp = find_vpid(who);
264 else
265 pgrp = task_pgrp(current);
266 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
267 niceval = 20 - task_nice(p);
268 if (niceval > retval)
269 retval = niceval;
270 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
271 break;
272 case PRIO_USER:
273 user = (struct user_struct *) cred->user;
274 if (!who)
275 who = cred->uid;
276 else if ((who != cred->uid) &&
277 !(user = find_user(who)))
278 goto out_unlock; /* No processes for this user */
279
280 do_each_thread(g, p) {
281 if (__task_cred(p)->uid == who) {
282 niceval = 20 - task_nice(p);
283 if (niceval > retval)
284 retval = niceval;
285 }
286 } while_each_thread(g, p);
287 if (who != cred->uid)
288 free_uid(user); /* for find_user() */
289 break;
290 }
291 out_unlock:
292 read_unlock(&tasklist_lock);
293 rcu_read_unlock();
294
295 return retval;
296 }
297
298 /**
299 * emergency_restart - reboot the system
300 *
301 * Without shutting down any hardware or taking any locks
302 * reboot the system. This is called when we know we are in
303 * trouble so this is our best effort to reboot. This is
304 * safe to call in interrupt context.
305 */
306 void emergency_restart(void)
307 {
308 kmsg_dump(KMSG_DUMP_EMERG);
309 machine_emergency_restart();
310 }
311 EXPORT_SYMBOL_GPL(emergency_restart);
312
313 void kernel_restart_prepare(char *cmd)
314 {
315 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
316 system_state = SYSTEM_RESTART;
317 usermodehelper_disable();
318 device_shutdown();
319 syscore_shutdown();
320 }
321
322 /**
323 * kernel_restart - reboot the system
324 * @cmd: pointer to buffer containing command to execute for restart
325 * or %NULL
326 *
327 * Shutdown everything and perform a clean reboot.
328 * This is not safe to call in interrupt context.
329 */
330 void kernel_restart(char *cmd)
331 {
332 kernel_restart_prepare(cmd);
333 if (!cmd)
334 printk(KERN_EMERG "Restarting system.\n");
335 else
336 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
337 kmsg_dump(KMSG_DUMP_RESTART);
338 machine_restart(cmd);
339 }
340 EXPORT_SYMBOL_GPL(kernel_restart);
341
342 static void kernel_shutdown_prepare(enum system_states state)
343 {
344 blocking_notifier_call_chain(&reboot_notifier_list,
345 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
346 system_state = state;
347 usermodehelper_disable();
348 device_shutdown();
349 }
350 /**
351 * kernel_halt - halt the system
352 *
353 * Shutdown everything and perform a clean system halt.
354 */
355 void kernel_halt(void)
356 {
357 kernel_shutdown_prepare(SYSTEM_HALT);
358 syscore_shutdown();
359 printk(KERN_EMERG "System halted.\n");
360 kmsg_dump(KMSG_DUMP_HALT);
361 machine_halt();
362 }
363
364 EXPORT_SYMBOL_GPL(kernel_halt);
365
366 /**
367 * kernel_power_off - power_off the system
368 *
369 * Shutdown everything and perform a clean system power_off.
370 */
371 void kernel_power_off(void)
372 {
373 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
374 if (pm_power_off_prepare)
375 pm_power_off_prepare();
376 disable_nonboot_cpus();
377 syscore_shutdown();
378 printk(KERN_EMERG "Power down.\n");
379 kmsg_dump(KMSG_DUMP_POWEROFF);
380 machine_power_off();
381 }
382 EXPORT_SYMBOL_GPL(kernel_power_off);
383
384 static DEFINE_MUTEX(reboot_mutex);
385
386 /*
387 * Reboot system call: for obvious reasons only root may call it,
388 * and even root needs to set up some magic numbers in the registers
389 * so that some mistake won't make this reboot the whole machine.
390 * You can also set the meaning of the ctrl-alt-del-key here.
391 *
392 * reboot doesn't sync: do that yourself before calling this.
393 */
394 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
395 void __user *, arg)
396 {
397 char buffer[256];
398 int ret = 0;
399
400 /* We only trust the superuser with rebooting the system. */
401 if (!capable(CAP_SYS_BOOT))
402 return -EPERM;
403
404 /* For safety, we require "magic" arguments. */
405 if (magic1 != LINUX_REBOOT_MAGIC1 ||
406 (magic2 != LINUX_REBOOT_MAGIC2 &&
407 magic2 != LINUX_REBOOT_MAGIC2A &&
408 magic2 != LINUX_REBOOT_MAGIC2B &&
409 magic2 != LINUX_REBOOT_MAGIC2C))
410 return -EINVAL;
411
412 /* Instead of trying to make the power_off code look like
413 * halt when pm_power_off is not set do it the easy way.
414 */
415 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
416 cmd = LINUX_REBOOT_CMD_HALT;
417
418 mutex_lock(&reboot_mutex);
419 switch (cmd) {
420 case LINUX_REBOOT_CMD_RESTART:
421 kernel_restart(NULL);
422 break;
423
424 case LINUX_REBOOT_CMD_CAD_ON:
425 C_A_D = 1;
426 break;
427
428 case LINUX_REBOOT_CMD_CAD_OFF:
429 C_A_D = 0;
430 break;
431
432 case LINUX_REBOOT_CMD_HALT:
433 kernel_halt();
434 do_exit(0);
435 panic("cannot halt");
436
437 case LINUX_REBOOT_CMD_POWER_OFF:
438 kernel_power_off();
439 do_exit(0);
440 break;
441
442 case LINUX_REBOOT_CMD_RESTART2:
443 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
444 ret = -EFAULT;
445 break;
446 }
447 buffer[sizeof(buffer) - 1] = '\0';
448
449 kernel_restart(buffer);
450 break;
451
452 #ifdef CONFIG_KEXEC
453 case LINUX_REBOOT_CMD_KEXEC:
454 ret = kernel_kexec();
455 break;
456 #endif
457
458 #ifdef CONFIG_HIBERNATION
459 case LINUX_REBOOT_CMD_SW_SUSPEND:
460 ret = hibernate();
461 break;
462 #endif
463
464 default:
465 ret = -EINVAL;
466 break;
467 }
468 mutex_unlock(&reboot_mutex);
469 return ret;
470 }
471
472 static void deferred_cad(struct work_struct *dummy)
473 {
474 kernel_restart(NULL);
475 }
476
477 /*
478 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
479 * As it's called within an interrupt, it may NOT sync: the only choice
480 * is whether to reboot at once, or just ignore the ctrl-alt-del.
481 */
482 void ctrl_alt_del(void)
483 {
484 static DECLARE_WORK(cad_work, deferred_cad);
485
486 if (C_A_D)
487 schedule_work(&cad_work);
488 else
489 kill_cad_pid(SIGINT, 1);
490 }
491
492 /*
493 * Unprivileged users may change the real gid to the effective gid
494 * or vice versa. (BSD-style)
495 *
496 * If you set the real gid at all, or set the effective gid to a value not
497 * equal to the real gid, then the saved gid is set to the new effective gid.
498 *
499 * This makes it possible for a setgid program to completely drop its
500 * privileges, which is often a useful assertion to make when you are doing
501 * a security audit over a program.
502 *
503 * The general idea is that a program which uses just setregid() will be
504 * 100% compatible with BSD. A program which uses just setgid() will be
505 * 100% compatible with POSIX with saved IDs.
506 *
507 * SMP: There are not races, the GIDs are checked only by filesystem
508 * operations (as far as semantic preservation is concerned).
509 */
510 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
511 {
512 const struct cred *old;
513 struct cred *new;
514 int retval;
515
516 new = prepare_creds();
517 if (!new)
518 return -ENOMEM;
519 old = current_cred();
520
521 retval = -EPERM;
522 if (rgid != (gid_t) -1) {
523 if (old->gid == rgid ||
524 old->egid == rgid ||
525 nsown_capable(CAP_SETGID))
526 new->gid = rgid;
527 else
528 goto error;
529 }
530 if (egid != (gid_t) -1) {
531 if (old->gid == egid ||
532 old->egid == egid ||
533 old->sgid == egid ||
534 nsown_capable(CAP_SETGID))
535 new->egid = egid;
536 else
537 goto error;
538 }
539
540 if (rgid != (gid_t) -1 ||
541 (egid != (gid_t) -1 && egid != old->gid))
542 new->sgid = new->egid;
543 new->fsgid = new->egid;
544
545 return commit_creds(new);
546
547 error:
548 abort_creds(new);
549 return retval;
550 }
551
552 /*
553 * setgid() is implemented like SysV w/ SAVED_IDS
554 *
555 * SMP: Same implicit races as above.
556 */
557 SYSCALL_DEFINE1(setgid, gid_t, gid)
558 {
559 const struct cred *old;
560 struct cred *new;
561 int retval;
562
563 new = prepare_creds();
564 if (!new)
565 return -ENOMEM;
566 old = current_cred();
567
568 retval = -EPERM;
569 if (nsown_capable(CAP_SETGID))
570 new->gid = new->egid = new->sgid = new->fsgid = gid;
571 else if (gid == old->gid || gid == old->sgid)
572 new->egid = new->fsgid = gid;
573 else
574 goto error;
575
576 return commit_creds(new);
577
578 error:
579 abort_creds(new);
580 return retval;
581 }
582
583 /*
584 * change the user struct in a credentials set to match the new UID
585 */
586 static int set_user(struct cred *new)
587 {
588 struct user_struct *new_user;
589
590 new_user = alloc_uid(current_user_ns(), new->uid);
591 if (!new_user)
592 return -EAGAIN;
593
594 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
595 new_user != INIT_USER) {
596 free_uid(new_user);
597 return -EAGAIN;
598 }
599
600 free_uid(new->user);
601 new->user = new_user;
602 return 0;
603 }
604
605 /*
606 * Unprivileged users may change the real uid to the effective uid
607 * or vice versa. (BSD-style)
608 *
609 * If you set the real uid at all, or set the effective uid to a value not
610 * equal to the real uid, then the saved uid is set to the new effective uid.
611 *
612 * This makes it possible for a setuid program to completely drop its
613 * privileges, which is often a useful assertion to make when you are doing
614 * a security audit over a program.
615 *
616 * The general idea is that a program which uses just setreuid() will be
617 * 100% compatible with BSD. A program which uses just setuid() will be
618 * 100% compatible with POSIX with saved IDs.
619 */
620 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
621 {
622 const struct cred *old;
623 struct cred *new;
624 int retval;
625
626 new = prepare_creds();
627 if (!new)
628 return -ENOMEM;
629 old = current_cred();
630
631 retval = -EPERM;
632 if (ruid != (uid_t) -1) {
633 new->uid = ruid;
634 if (old->uid != ruid &&
635 old->euid != ruid &&
636 !nsown_capable(CAP_SETUID))
637 goto error;
638 }
639
640 if (euid != (uid_t) -1) {
641 new->euid = euid;
642 if (old->uid != euid &&
643 old->euid != euid &&
644 old->suid != euid &&
645 !nsown_capable(CAP_SETUID))
646 goto error;
647 }
648
649 if (new->uid != old->uid) {
650 retval = set_user(new);
651 if (retval < 0)
652 goto error;
653 }
654 if (ruid != (uid_t) -1 ||
655 (euid != (uid_t) -1 && euid != old->uid))
656 new->suid = new->euid;
657 new->fsuid = new->euid;
658
659 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
660 if (retval < 0)
661 goto error;
662
663 return commit_creds(new);
664
665 error:
666 abort_creds(new);
667 return retval;
668 }
669
670 /*
671 * setuid() is implemented like SysV with SAVED_IDS
672 *
673 * Note that SAVED_ID's is deficient in that a setuid root program
674 * like sendmail, for example, cannot set its uid to be a normal
675 * user and then switch back, because if you're root, setuid() sets
676 * the saved uid too. If you don't like this, blame the bright people
677 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
678 * will allow a root program to temporarily drop privileges and be able to
679 * regain them by swapping the real and effective uid.
680 */
681 SYSCALL_DEFINE1(setuid, uid_t, uid)
682 {
683 const struct cred *old;
684 struct cred *new;
685 int retval;
686
687 new = prepare_creds();
688 if (!new)
689 return -ENOMEM;
690 old = current_cred();
691
692 retval = -EPERM;
693 if (nsown_capable(CAP_SETUID)) {
694 new->suid = new->uid = uid;
695 if (uid != old->uid) {
696 retval = set_user(new);
697 if (retval < 0)
698 goto error;
699 }
700 } else if (uid != old->uid && uid != new->suid) {
701 goto error;
702 }
703
704 new->fsuid = new->euid = uid;
705
706 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
707 if (retval < 0)
708 goto error;
709
710 return commit_creds(new);
711
712 error:
713 abort_creds(new);
714 return retval;
715 }
716
717
718 /*
719 * This function implements a generic ability to update ruid, euid,
720 * and suid. This allows you to implement the 4.4 compatible seteuid().
721 */
722 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
723 {
724 const struct cred *old;
725 struct cred *new;
726 int retval;
727
728 new = prepare_creds();
729 if (!new)
730 return -ENOMEM;
731
732 old = current_cred();
733
734 retval = -EPERM;
735 if (!nsown_capable(CAP_SETUID)) {
736 if (ruid != (uid_t) -1 && ruid != old->uid &&
737 ruid != old->euid && ruid != old->suid)
738 goto error;
739 if (euid != (uid_t) -1 && euid != old->uid &&
740 euid != old->euid && euid != old->suid)
741 goto error;
742 if (suid != (uid_t) -1 && suid != old->uid &&
743 suid != old->euid && suid != old->suid)
744 goto error;
745 }
746
747 if (ruid != (uid_t) -1) {
748 new->uid = ruid;
749 if (ruid != old->uid) {
750 retval = set_user(new);
751 if (retval < 0)
752 goto error;
753 }
754 }
755 if (euid != (uid_t) -1)
756 new->euid = euid;
757 if (suid != (uid_t) -1)
758 new->suid = suid;
759 new->fsuid = new->euid;
760
761 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
762 if (retval < 0)
763 goto error;
764
765 return commit_creds(new);
766
767 error:
768 abort_creds(new);
769 return retval;
770 }
771
772 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
773 {
774 const struct cred *cred = current_cred();
775 int retval;
776
777 if (!(retval = put_user(cred->uid, ruid)) &&
778 !(retval = put_user(cred->euid, euid)))
779 retval = put_user(cred->suid, suid);
780
781 return retval;
782 }
783
784 /*
785 * Same as above, but for rgid, egid, sgid.
786 */
787 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
788 {
789 const struct cred *old;
790 struct cred *new;
791 int retval;
792
793 new = prepare_creds();
794 if (!new)
795 return -ENOMEM;
796 old = current_cred();
797
798 retval = -EPERM;
799 if (!nsown_capable(CAP_SETGID)) {
800 if (rgid != (gid_t) -1 && rgid != old->gid &&
801 rgid != old->egid && rgid != old->sgid)
802 goto error;
803 if (egid != (gid_t) -1 && egid != old->gid &&
804 egid != old->egid && egid != old->sgid)
805 goto error;
806 if (sgid != (gid_t) -1 && sgid != old->gid &&
807 sgid != old->egid && sgid != old->sgid)
808 goto error;
809 }
810
811 if (rgid != (gid_t) -1)
812 new->gid = rgid;
813 if (egid != (gid_t) -1)
814 new->egid = egid;
815 if (sgid != (gid_t) -1)
816 new->sgid = sgid;
817 new->fsgid = new->egid;
818
819 return commit_creds(new);
820
821 error:
822 abort_creds(new);
823 return retval;
824 }
825
826 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
827 {
828 const struct cred *cred = current_cred();
829 int retval;
830
831 if (!(retval = put_user(cred->gid, rgid)) &&
832 !(retval = put_user(cred->egid, egid)))
833 retval = put_user(cred->sgid, sgid);
834
835 return retval;
836 }
837
838
839 /*
840 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
841 * is used for "access()" and for the NFS daemon (letting nfsd stay at
842 * whatever uid it wants to). It normally shadows "euid", except when
843 * explicitly set by setfsuid() or for access..
844 */
845 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
846 {
847 const struct cred *old;
848 struct cred *new;
849 uid_t old_fsuid;
850
851 new = prepare_creds();
852 if (!new)
853 return current_fsuid();
854 old = current_cred();
855 old_fsuid = old->fsuid;
856
857 if (uid == old->uid || uid == old->euid ||
858 uid == old->suid || uid == old->fsuid ||
859 nsown_capable(CAP_SETUID)) {
860 if (uid != old_fsuid) {
861 new->fsuid = uid;
862 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
863 goto change_okay;
864 }
865 }
866
867 abort_creds(new);
868 return old_fsuid;
869
870 change_okay:
871 commit_creds(new);
872 return old_fsuid;
873 }
874
875 /*
876 * Samma på svenska..
877 */
878 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
879 {
880 const struct cred *old;
881 struct cred *new;
882 gid_t old_fsgid;
883
884 new = prepare_creds();
885 if (!new)
886 return current_fsgid();
887 old = current_cred();
888 old_fsgid = old->fsgid;
889
890 if (gid == old->gid || gid == old->egid ||
891 gid == old->sgid || gid == old->fsgid ||
892 nsown_capable(CAP_SETGID)) {
893 if (gid != old_fsgid) {
894 new->fsgid = gid;
895 goto change_okay;
896 }
897 }
898
899 abort_creds(new);
900 return old_fsgid;
901
902 change_okay:
903 commit_creds(new);
904 return old_fsgid;
905 }
906
907 void do_sys_times(struct tms *tms)
908 {
909 cputime_t tgutime, tgstime, cutime, cstime;
910
911 spin_lock_irq(&current->sighand->siglock);
912 thread_group_times(current, &tgutime, &tgstime);
913 cutime = current->signal->cutime;
914 cstime = current->signal->cstime;
915 spin_unlock_irq(&current->sighand->siglock);
916 tms->tms_utime = cputime_to_clock_t(tgutime);
917 tms->tms_stime = cputime_to_clock_t(tgstime);
918 tms->tms_cutime = cputime_to_clock_t(cutime);
919 tms->tms_cstime = cputime_to_clock_t(cstime);
920 }
921
922 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
923 {
924 if (tbuf) {
925 struct tms tmp;
926
927 do_sys_times(&tmp);
928 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
929 return -EFAULT;
930 }
931 force_successful_syscall_return();
932 return (long) jiffies_64_to_clock_t(get_jiffies_64());
933 }
934
935 /*
936 * This needs some heavy checking ...
937 * I just haven't the stomach for it. I also don't fully
938 * understand sessions/pgrp etc. Let somebody who does explain it.
939 *
940 * OK, I think I have the protection semantics right.... this is really
941 * only important on a multi-user system anyway, to make sure one user
942 * can't send a signal to a process owned by another. -TYT, 12/12/91
943 *
944 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
945 * LBT 04.03.94
946 */
947 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
948 {
949 struct task_struct *p;
950 struct task_struct *group_leader = current->group_leader;
951 struct pid *pgrp;
952 int err;
953
954 if (!pid)
955 pid = task_pid_vnr(group_leader);
956 if (!pgid)
957 pgid = pid;
958 if (pgid < 0)
959 return -EINVAL;
960 rcu_read_lock();
961
962 /* From this point forward we keep holding onto the tasklist lock
963 * so that our parent does not change from under us. -DaveM
964 */
965 write_lock_irq(&tasklist_lock);
966
967 err = -ESRCH;
968 p = find_task_by_vpid(pid);
969 if (!p)
970 goto out;
971
972 err = -EINVAL;
973 if (!thread_group_leader(p))
974 goto out;
975
976 if (same_thread_group(p->real_parent, group_leader)) {
977 err = -EPERM;
978 if (task_session(p) != task_session(group_leader))
979 goto out;
980 err = -EACCES;
981 if (p->did_exec)
982 goto out;
983 } else {
984 err = -ESRCH;
985 if (p != group_leader)
986 goto out;
987 }
988
989 err = -EPERM;
990 if (p->signal->leader)
991 goto out;
992
993 pgrp = task_pid(p);
994 if (pgid != pid) {
995 struct task_struct *g;
996
997 pgrp = find_vpid(pgid);
998 g = pid_task(pgrp, PIDTYPE_PGID);
999 if (!g || task_session(g) != task_session(group_leader))
1000 goto out;
1001 }
1002
1003 err = security_task_setpgid(p, pgid);
1004 if (err)
1005 goto out;
1006
1007 if (task_pgrp(p) != pgrp)
1008 change_pid(p, PIDTYPE_PGID, pgrp);
1009
1010 err = 0;
1011 out:
1012 /* All paths lead to here, thus we are safe. -DaveM */
1013 write_unlock_irq(&tasklist_lock);
1014 rcu_read_unlock();
1015 return err;
1016 }
1017
1018 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1019 {
1020 struct task_struct *p;
1021 struct pid *grp;
1022 int retval;
1023
1024 rcu_read_lock();
1025 if (!pid)
1026 grp = task_pgrp(current);
1027 else {
1028 retval = -ESRCH;
1029 p = find_task_by_vpid(pid);
1030 if (!p)
1031 goto out;
1032 grp = task_pgrp(p);
1033 if (!grp)
1034 goto out;
1035
1036 retval = security_task_getpgid(p);
1037 if (retval)
1038 goto out;
1039 }
1040 retval = pid_vnr(grp);
1041 out:
1042 rcu_read_unlock();
1043 return retval;
1044 }
1045
1046 #ifdef __ARCH_WANT_SYS_GETPGRP
1047
1048 SYSCALL_DEFINE0(getpgrp)
1049 {
1050 return sys_getpgid(0);
1051 }
1052
1053 #endif
1054
1055 SYSCALL_DEFINE1(getsid, pid_t, pid)
1056 {
1057 struct task_struct *p;
1058 struct pid *sid;
1059 int retval;
1060
1061 rcu_read_lock();
1062 if (!pid)
1063 sid = task_session(current);
1064 else {
1065 retval = -ESRCH;
1066 p = find_task_by_vpid(pid);
1067 if (!p)
1068 goto out;
1069 sid = task_session(p);
1070 if (!sid)
1071 goto out;
1072
1073 retval = security_task_getsid(p);
1074 if (retval)
1075 goto out;
1076 }
1077 retval = pid_vnr(sid);
1078 out:
1079 rcu_read_unlock();
1080 return retval;
1081 }
1082
1083 SYSCALL_DEFINE0(setsid)
1084 {
1085 struct task_struct *group_leader = current->group_leader;
1086 struct pid *sid = task_pid(group_leader);
1087 pid_t session = pid_vnr(sid);
1088 int err = -EPERM;
1089
1090 write_lock_irq(&tasklist_lock);
1091 /* Fail if I am already a session leader */
1092 if (group_leader->signal->leader)
1093 goto out;
1094
1095 /* Fail if a process group id already exists that equals the
1096 * proposed session id.
1097 */
1098 if (pid_task(sid, PIDTYPE_PGID))
1099 goto out;
1100
1101 group_leader->signal->leader = 1;
1102 __set_special_pids(sid);
1103
1104 proc_clear_tty(group_leader);
1105
1106 err = session;
1107 out:
1108 write_unlock_irq(&tasklist_lock);
1109 if (err > 0) {
1110 proc_sid_connector(group_leader);
1111 sched_autogroup_create_attach(group_leader);
1112 }
1113 return err;
1114 }
1115
1116 DECLARE_RWSEM(uts_sem);
1117
1118 #ifdef COMPAT_UTS_MACHINE
1119 #define override_architecture(name) \
1120 (personality(current->personality) == PER_LINUX32 && \
1121 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1122 sizeof(COMPAT_UTS_MACHINE)))
1123 #else
1124 #define override_architecture(name) 0
1125 #endif
1126
1127 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1128 {
1129 int errno = 0;
1130
1131 down_read(&uts_sem);
1132 if (copy_to_user(name, utsname(), sizeof *name))
1133 errno = -EFAULT;
1134 up_read(&uts_sem);
1135
1136 if (!errno && override_architecture(name))
1137 errno = -EFAULT;
1138 return errno;
1139 }
1140
1141 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1142 /*
1143 * Old cruft
1144 */
1145 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1146 {
1147 int error = 0;
1148
1149 if (!name)
1150 return -EFAULT;
1151
1152 down_read(&uts_sem);
1153 if (copy_to_user(name, utsname(), sizeof(*name)))
1154 error = -EFAULT;
1155 up_read(&uts_sem);
1156
1157 if (!error && override_architecture(name))
1158 error = -EFAULT;
1159 return error;
1160 }
1161
1162 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1163 {
1164 int error;
1165
1166 if (!name)
1167 return -EFAULT;
1168 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1169 return -EFAULT;
1170
1171 down_read(&uts_sem);
1172 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1173 __OLD_UTS_LEN);
1174 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1175 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1176 __OLD_UTS_LEN);
1177 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1178 error |= __copy_to_user(&name->release, &utsname()->release,
1179 __OLD_UTS_LEN);
1180 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1181 error |= __copy_to_user(&name->version, &utsname()->version,
1182 __OLD_UTS_LEN);
1183 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1184 error |= __copy_to_user(&name->machine, &utsname()->machine,
1185 __OLD_UTS_LEN);
1186 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1187 up_read(&uts_sem);
1188
1189 if (!error && override_architecture(name))
1190 error = -EFAULT;
1191 return error ? -EFAULT : 0;
1192 }
1193 #endif
1194
1195 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1196 {
1197 int errno;
1198 char tmp[__NEW_UTS_LEN];
1199
1200 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1201 return -EPERM;
1202
1203 if (len < 0 || len > __NEW_UTS_LEN)
1204 return -EINVAL;
1205 down_write(&uts_sem);
1206 errno = -EFAULT;
1207 if (!copy_from_user(tmp, name, len)) {
1208 struct new_utsname *u = utsname();
1209
1210 memcpy(u->nodename, tmp, len);
1211 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1212 errno = 0;
1213 }
1214 up_write(&uts_sem);
1215 return errno;
1216 }
1217
1218 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1219
1220 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1221 {
1222 int i, errno;
1223 struct new_utsname *u;
1224
1225 if (len < 0)
1226 return -EINVAL;
1227 down_read(&uts_sem);
1228 u = utsname();
1229 i = 1 + strlen(u->nodename);
1230 if (i > len)
1231 i = len;
1232 errno = 0;
1233 if (copy_to_user(name, u->nodename, i))
1234 errno = -EFAULT;
1235 up_read(&uts_sem);
1236 return errno;
1237 }
1238
1239 #endif
1240
1241 /*
1242 * Only setdomainname; getdomainname can be implemented by calling
1243 * uname()
1244 */
1245 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1246 {
1247 int errno;
1248 char tmp[__NEW_UTS_LEN];
1249
1250 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1251 return -EPERM;
1252 if (len < 0 || len > __NEW_UTS_LEN)
1253 return -EINVAL;
1254
1255 down_write(&uts_sem);
1256 errno = -EFAULT;
1257 if (!copy_from_user(tmp, name, len)) {
1258 struct new_utsname *u = utsname();
1259
1260 memcpy(u->domainname, tmp, len);
1261 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1262 errno = 0;
1263 }
1264 up_write(&uts_sem);
1265 return errno;
1266 }
1267
1268 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1269 {
1270 struct rlimit value;
1271 int ret;
1272
1273 ret = do_prlimit(current, resource, NULL, &value);
1274 if (!ret)
1275 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1276
1277 return ret;
1278 }
1279
1280 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1281
1282 /*
1283 * Back compatibility for getrlimit. Needed for some apps.
1284 */
1285
1286 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1287 struct rlimit __user *, rlim)
1288 {
1289 struct rlimit x;
1290 if (resource >= RLIM_NLIMITS)
1291 return -EINVAL;
1292
1293 task_lock(current->group_leader);
1294 x = current->signal->rlim[resource];
1295 task_unlock(current->group_leader);
1296 if (x.rlim_cur > 0x7FFFFFFF)
1297 x.rlim_cur = 0x7FFFFFFF;
1298 if (x.rlim_max > 0x7FFFFFFF)
1299 x.rlim_max = 0x7FFFFFFF;
1300 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1301 }
1302
1303 #endif
1304
1305 static inline bool rlim64_is_infinity(__u64 rlim64)
1306 {
1307 #if BITS_PER_LONG < 64
1308 return rlim64 >= ULONG_MAX;
1309 #else
1310 return rlim64 == RLIM64_INFINITY;
1311 #endif
1312 }
1313
1314 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1315 {
1316 if (rlim->rlim_cur == RLIM_INFINITY)
1317 rlim64->rlim_cur = RLIM64_INFINITY;
1318 else
1319 rlim64->rlim_cur = rlim->rlim_cur;
1320 if (rlim->rlim_max == RLIM_INFINITY)
1321 rlim64->rlim_max = RLIM64_INFINITY;
1322 else
1323 rlim64->rlim_max = rlim->rlim_max;
1324 }
1325
1326 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1327 {
1328 if (rlim64_is_infinity(rlim64->rlim_cur))
1329 rlim->rlim_cur = RLIM_INFINITY;
1330 else
1331 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1332 if (rlim64_is_infinity(rlim64->rlim_max))
1333 rlim->rlim_max = RLIM_INFINITY;
1334 else
1335 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1336 }
1337
1338 /* make sure you are allowed to change @tsk limits before calling this */
1339 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1340 struct rlimit *new_rlim, struct rlimit *old_rlim)
1341 {
1342 struct rlimit *rlim;
1343 int retval = 0;
1344
1345 if (resource >= RLIM_NLIMITS)
1346 return -EINVAL;
1347 if (new_rlim) {
1348 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1349 return -EINVAL;
1350 if (resource == RLIMIT_NOFILE &&
1351 new_rlim->rlim_max > sysctl_nr_open)
1352 return -EPERM;
1353 }
1354
1355 /* protect tsk->signal and tsk->sighand from disappearing */
1356 read_lock(&tasklist_lock);
1357 if (!tsk->sighand) {
1358 retval = -ESRCH;
1359 goto out;
1360 }
1361
1362 rlim = tsk->signal->rlim + resource;
1363 task_lock(tsk->group_leader);
1364 if (new_rlim) {
1365 /* Keep the capable check against init_user_ns until
1366 cgroups can contain all limits */
1367 if (new_rlim->rlim_max > rlim->rlim_max &&
1368 !capable(CAP_SYS_RESOURCE))
1369 retval = -EPERM;
1370 if (!retval)
1371 retval = security_task_setrlimit(tsk->group_leader,
1372 resource, new_rlim);
1373 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1374 /*
1375 * The caller is asking for an immediate RLIMIT_CPU
1376 * expiry. But we use the zero value to mean "it was
1377 * never set". So let's cheat and make it one second
1378 * instead
1379 */
1380 new_rlim->rlim_cur = 1;
1381 }
1382 }
1383 if (!retval) {
1384 if (old_rlim)
1385 *old_rlim = *rlim;
1386 if (new_rlim)
1387 *rlim = *new_rlim;
1388 }
1389 task_unlock(tsk->group_leader);
1390
1391 /*
1392 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1393 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1394 * very long-standing error, and fixing it now risks breakage of
1395 * applications, so we live with it
1396 */
1397 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1398 new_rlim->rlim_cur != RLIM_INFINITY)
1399 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1400 out:
1401 read_unlock(&tasklist_lock);
1402 return retval;
1403 }
1404
1405 /* rcu lock must be held */
1406 static int check_prlimit_permission(struct task_struct *task)
1407 {
1408 const struct cred *cred = current_cred(), *tcred;
1409
1410 if (current == task)
1411 return 0;
1412
1413 tcred = __task_cred(task);
1414 if (cred->user->user_ns == tcred->user->user_ns &&
1415 (cred->uid == tcred->euid &&
1416 cred->uid == tcred->suid &&
1417 cred->uid == tcred->uid &&
1418 cred->gid == tcred->egid &&
1419 cred->gid == tcred->sgid &&
1420 cred->gid == tcred->gid))
1421 return 0;
1422 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1423 return 0;
1424
1425 return -EPERM;
1426 }
1427
1428 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1429 const struct rlimit64 __user *, new_rlim,
1430 struct rlimit64 __user *, old_rlim)
1431 {
1432 struct rlimit64 old64, new64;
1433 struct rlimit old, new;
1434 struct task_struct *tsk;
1435 int ret;
1436
1437 if (new_rlim) {
1438 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1439 return -EFAULT;
1440 rlim64_to_rlim(&new64, &new);
1441 }
1442
1443 rcu_read_lock();
1444 tsk = pid ? find_task_by_vpid(pid) : current;
1445 if (!tsk) {
1446 rcu_read_unlock();
1447 return -ESRCH;
1448 }
1449 ret = check_prlimit_permission(tsk);
1450 if (ret) {
1451 rcu_read_unlock();
1452 return ret;
1453 }
1454 get_task_struct(tsk);
1455 rcu_read_unlock();
1456
1457 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1458 old_rlim ? &old : NULL);
1459
1460 if (!ret && old_rlim) {
1461 rlim_to_rlim64(&old, &old64);
1462 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1463 ret = -EFAULT;
1464 }
1465
1466 put_task_struct(tsk);
1467 return ret;
1468 }
1469
1470 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1471 {
1472 struct rlimit new_rlim;
1473
1474 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1475 return -EFAULT;
1476 return do_prlimit(current, resource, &new_rlim, NULL);
1477 }
1478
1479 /*
1480 * It would make sense to put struct rusage in the task_struct,
1481 * except that would make the task_struct be *really big*. After
1482 * task_struct gets moved into malloc'ed memory, it would
1483 * make sense to do this. It will make moving the rest of the information
1484 * a lot simpler! (Which we're not doing right now because we're not
1485 * measuring them yet).
1486 *
1487 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1488 * races with threads incrementing their own counters. But since word
1489 * reads are atomic, we either get new values or old values and we don't
1490 * care which for the sums. We always take the siglock to protect reading
1491 * the c* fields from p->signal from races with exit.c updating those
1492 * fields when reaping, so a sample either gets all the additions of a
1493 * given child after it's reaped, or none so this sample is before reaping.
1494 *
1495 * Locking:
1496 * We need to take the siglock for CHILDEREN, SELF and BOTH
1497 * for the cases current multithreaded, non-current single threaded
1498 * non-current multithreaded. Thread traversal is now safe with
1499 * the siglock held.
1500 * Strictly speaking, we donot need to take the siglock if we are current and
1501 * single threaded, as no one else can take our signal_struct away, no one
1502 * else can reap the children to update signal->c* counters, and no one else
1503 * can race with the signal-> fields. If we do not take any lock, the
1504 * signal-> fields could be read out of order while another thread was just
1505 * exiting. So we should place a read memory barrier when we avoid the lock.
1506 * On the writer side, write memory barrier is implied in __exit_signal
1507 * as __exit_signal releases the siglock spinlock after updating the signal->
1508 * fields. But we don't do this yet to keep things simple.
1509 *
1510 */
1511
1512 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1513 {
1514 r->ru_nvcsw += t->nvcsw;
1515 r->ru_nivcsw += t->nivcsw;
1516 r->ru_minflt += t->min_flt;
1517 r->ru_majflt += t->maj_flt;
1518 r->ru_inblock += task_io_get_inblock(t);
1519 r->ru_oublock += task_io_get_oublock(t);
1520 }
1521
1522 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1523 {
1524 struct task_struct *t;
1525 unsigned long flags;
1526 cputime_t tgutime, tgstime, utime, stime;
1527 unsigned long maxrss = 0;
1528
1529 memset((char *) r, 0, sizeof *r);
1530 utime = stime = cputime_zero;
1531
1532 if (who == RUSAGE_THREAD) {
1533 task_times(current, &utime, &stime);
1534 accumulate_thread_rusage(p, r);
1535 maxrss = p->signal->maxrss;
1536 goto out;
1537 }
1538
1539 if (!lock_task_sighand(p, &flags))
1540 return;
1541
1542 switch (who) {
1543 case RUSAGE_BOTH:
1544 case RUSAGE_CHILDREN:
1545 utime = p->signal->cutime;
1546 stime = p->signal->cstime;
1547 r->ru_nvcsw = p->signal->cnvcsw;
1548 r->ru_nivcsw = p->signal->cnivcsw;
1549 r->ru_minflt = p->signal->cmin_flt;
1550 r->ru_majflt = p->signal->cmaj_flt;
1551 r->ru_inblock = p->signal->cinblock;
1552 r->ru_oublock = p->signal->coublock;
1553 maxrss = p->signal->cmaxrss;
1554
1555 if (who == RUSAGE_CHILDREN)
1556 break;
1557
1558 case RUSAGE_SELF:
1559 thread_group_times(p, &tgutime, &tgstime);
1560 utime = cputime_add(utime, tgutime);
1561 stime = cputime_add(stime, tgstime);
1562 r->ru_nvcsw += p->signal->nvcsw;
1563 r->ru_nivcsw += p->signal->nivcsw;
1564 r->ru_minflt += p->signal->min_flt;
1565 r->ru_majflt += p->signal->maj_flt;
1566 r->ru_inblock += p->signal->inblock;
1567 r->ru_oublock += p->signal->oublock;
1568 if (maxrss < p->signal->maxrss)
1569 maxrss = p->signal->maxrss;
1570 t = p;
1571 do {
1572 accumulate_thread_rusage(t, r);
1573 t = next_thread(t);
1574 } while (t != p);
1575 break;
1576
1577 default:
1578 BUG();
1579 }
1580 unlock_task_sighand(p, &flags);
1581
1582 out:
1583 cputime_to_timeval(utime, &r->ru_utime);
1584 cputime_to_timeval(stime, &r->ru_stime);
1585
1586 if (who != RUSAGE_CHILDREN) {
1587 struct mm_struct *mm = get_task_mm(p);
1588 if (mm) {
1589 setmax_mm_hiwater_rss(&maxrss, mm);
1590 mmput(mm);
1591 }
1592 }
1593 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1594 }
1595
1596 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1597 {
1598 struct rusage r;
1599 k_getrusage(p, who, &r);
1600 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1601 }
1602
1603 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1604 {
1605 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1606 who != RUSAGE_THREAD)
1607 return -EINVAL;
1608 return getrusage(current, who, ru);
1609 }
1610
1611 SYSCALL_DEFINE1(umask, int, mask)
1612 {
1613 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1614 return mask;
1615 }
1616
1617 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1618 unsigned long, arg4, unsigned long, arg5)
1619 {
1620 struct task_struct *me = current;
1621 unsigned char comm[sizeof(me->comm)];
1622 long error;
1623
1624 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1625 if (error != -ENOSYS)
1626 return error;
1627
1628 error = 0;
1629 switch (option) {
1630 case PR_SET_PDEATHSIG:
1631 if (!valid_signal(arg2)) {
1632 error = -EINVAL;
1633 break;
1634 }
1635 me->pdeath_signal = arg2;
1636 error = 0;
1637 break;
1638 case PR_GET_PDEATHSIG:
1639 error = put_user(me->pdeath_signal, (int __user *)arg2);
1640 break;
1641 case PR_GET_DUMPABLE:
1642 error = get_dumpable(me->mm);
1643 break;
1644 case PR_SET_DUMPABLE:
1645 if (arg2 < 0 || arg2 > 1) {
1646 error = -EINVAL;
1647 break;
1648 }
1649 set_dumpable(me->mm, arg2);
1650 error = 0;
1651 break;
1652
1653 case PR_SET_UNALIGN:
1654 error = SET_UNALIGN_CTL(me, arg2);
1655 break;
1656 case PR_GET_UNALIGN:
1657 error = GET_UNALIGN_CTL(me, arg2);
1658 break;
1659 case PR_SET_FPEMU:
1660 error = SET_FPEMU_CTL(me, arg2);
1661 break;
1662 case PR_GET_FPEMU:
1663 error = GET_FPEMU_CTL(me, arg2);
1664 break;
1665 case PR_SET_FPEXC:
1666 error = SET_FPEXC_CTL(me, arg2);
1667 break;
1668 case PR_GET_FPEXC:
1669 error = GET_FPEXC_CTL(me, arg2);
1670 break;
1671 case PR_GET_TIMING:
1672 error = PR_TIMING_STATISTICAL;
1673 break;
1674 case PR_SET_TIMING:
1675 if (arg2 != PR_TIMING_STATISTICAL)
1676 error = -EINVAL;
1677 else
1678 error = 0;
1679 break;
1680
1681 case PR_SET_NAME:
1682 comm[sizeof(me->comm)-1] = 0;
1683 if (strncpy_from_user(comm, (char __user *)arg2,
1684 sizeof(me->comm) - 1) < 0)
1685 return -EFAULT;
1686 set_task_comm(me, comm);
1687 return 0;
1688 case PR_GET_NAME:
1689 get_task_comm(comm, me);
1690 if (copy_to_user((char __user *)arg2, comm,
1691 sizeof(comm)))
1692 return -EFAULT;
1693 return 0;
1694 case PR_GET_ENDIAN:
1695 error = GET_ENDIAN(me, arg2);
1696 break;
1697 case PR_SET_ENDIAN:
1698 error = SET_ENDIAN(me, arg2);
1699 break;
1700
1701 case PR_GET_SECCOMP:
1702 error = prctl_get_seccomp();
1703 break;
1704 case PR_SET_SECCOMP:
1705 error = prctl_set_seccomp(arg2);
1706 break;
1707 case PR_GET_TSC:
1708 error = GET_TSC_CTL(arg2);
1709 break;
1710 case PR_SET_TSC:
1711 error = SET_TSC_CTL(arg2);
1712 break;
1713 case PR_TASK_PERF_EVENTS_DISABLE:
1714 error = perf_event_task_disable();
1715 break;
1716 case PR_TASK_PERF_EVENTS_ENABLE:
1717 error = perf_event_task_enable();
1718 break;
1719 case PR_GET_TIMERSLACK:
1720 error = current->timer_slack_ns;
1721 break;
1722 case PR_SET_TIMERSLACK:
1723 if (arg2 <= 0)
1724 current->timer_slack_ns =
1725 current->default_timer_slack_ns;
1726 else
1727 current->timer_slack_ns = arg2;
1728 error = 0;
1729 break;
1730 case PR_MCE_KILL:
1731 if (arg4 | arg5)
1732 return -EINVAL;
1733 switch (arg2) {
1734 case PR_MCE_KILL_CLEAR:
1735 if (arg3 != 0)
1736 return -EINVAL;
1737 current->flags &= ~PF_MCE_PROCESS;
1738 break;
1739 case PR_MCE_KILL_SET:
1740 current->flags |= PF_MCE_PROCESS;
1741 if (arg3 == PR_MCE_KILL_EARLY)
1742 current->flags |= PF_MCE_EARLY;
1743 else if (arg3 == PR_MCE_KILL_LATE)
1744 current->flags &= ~PF_MCE_EARLY;
1745 else if (arg3 == PR_MCE_KILL_DEFAULT)
1746 current->flags &=
1747 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1748 else
1749 return -EINVAL;
1750 break;
1751 default:
1752 return -EINVAL;
1753 }
1754 error = 0;
1755 break;
1756 case PR_MCE_KILL_GET:
1757 if (arg2 | arg3 | arg4 | arg5)
1758 return -EINVAL;
1759 if (current->flags & PF_MCE_PROCESS)
1760 error = (current->flags & PF_MCE_EARLY) ?
1761 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1762 else
1763 error = PR_MCE_KILL_DEFAULT;
1764 break;
1765 default:
1766 error = -EINVAL;
1767 break;
1768 }
1769 return error;
1770 }
1771
1772 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1773 struct getcpu_cache __user *, unused)
1774 {
1775 int err = 0;
1776 int cpu = raw_smp_processor_id();
1777 if (cpup)
1778 err |= put_user(cpu, cpup);
1779 if (nodep)
1780 err |= put_user(cpu_to_node(cpu), nodep);
1781 return err ? -EFAULT : 0;
1782 }
1783
1784 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1785
1786 static void argv_cleanup(struct subprocess_info *info)
1787 {
1788 argv_free(info->argv);
1789 }
1790
1791 /**
1792 * orderly_poweroff - Trigger an orderly system poweroff
1793 * @force: force poweroff if command execution fails
1794 *
1795 * This may be called from any context to trigger a system shutdown.
1796 * If the orderly shutdown fails, it will force an immediate shutdown.
1797 */
1798 int orderly_poweroff(bool force)
1799 {
1800 int argc;
1801 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1802 static char *envp[] = {
1803 "HOME=/",
1804 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1805 NULL
1806 };
1807 int ret = -ENOMEM;
1808 struct subprocess_info *info;
1809
1810 if (argv == NULL) {
1811 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1812 __func__, poweroff_cmd);
1813 goto out;
1814 }
1815
1816 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1817 if (info == NULL) {
1818 argv_free(argv);
1819 goto out;
1820 }
1821
1822 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1823
1824 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1825
1826 out:
1827 if (ret && force) {
1828 printk(KERN_WARNING "Failed to start orderly shutdown: "
1829 "forcing the issue\n");
1830
1831 /* I guess this should try to kick off some daemon to
1832 sync and poweroff asap. Or not even bother syncing
1833 if we're doing an emergency shutdown? */
1834 emergency_sync();
1835 kernel_power_off();
1836 }
1837
1838 return ret;
1839 }
1840 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linus' kernel tree