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Merge remote-tracking branch 'ext4/dev'
[linux-2.6/next.git] / kernel / sys.c
blob18ee1d2f647408a6ffef7494ffdfef2043749dcf
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/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/perf_event.h>
16 #include <linux/resource.h>
17 #include <linux/kernel.h>
18 #include <linux/kexec.h>
19 #include <linux/workqueue.h>
20 #include <linux/capability.h>
21 #include <linux/device.h>
22 #include <linux/key.h>
23 #include <linux/times.h>
24 #include <linux/posix-timers.h>
25 #include <linux/security.h>
26 #include <linux/dcookies.h>
27 #include <linux/suspend.h>
28 #include <linux/tty.h>
29 #include <linux/signal.h>
30 #include <linux/cn_proc.h>
31 #include <linux/getcpu.h>
32 #include <linux/task_io_accounting_ops.h>
33 #include <linux/seccomp.h>
34 #include <linux/cpu.h>
35 #include <linux/personality.h>
36 #include <linux/ptrace.h>
37 #include <linux/fs_struct.h>
38 #include <linux/gfp.h>
39 #include <linux/syscore_ops.h>
40 #include <linux/version.h>
41 #include <linux/ctype.h>
42
43 #include <linux/compat.h>
44 #include <linux/syscalls.h>
45 #include <linux/kprobes.h>
46 #include <linux/user_namespace.h>
47
48 #include <linux/kmsg_dump.h>
49 /* Move somewhere else to avoid recompiling? */
50 #include <generated/utsrelease.h>
51
52 #include <asm/uaccess.h>
53 #include <asm/io.h>
54 #include <asm/unistd.h>
55
56 #ifndef SET_UNALIGN_CTL
57 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
58 #endif
59 #ifndef GET_UNALIGN_CTL
60 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
61 #endif
62 #ifndef SET_FPEMU_CTL
63 # define SET_FPEMU_CTL(a,b) (-EINVAL)
64 #endif
65 #ifndef GET_FPEMU_CTL
66 # define GET_FPEMU_CTL(a,b) (-EINVAL)
67 #endif
68 #ifndef SET_FPEXC_CTL
69 # define SET_FPEXC_CTL(a,b) (-EINVAL)
70 #endif
71 #ifndef GET_FPEXC_CTL
72 # define GET_FPEXC_CTL(a,b) (-EINVAL)
73 #endif
74 #ifndef GET_ENDIAN
75 # define GET_ENDIAN(a,b) (-EINVAL)
76 #endif
77 #ifndef SET_ENDIAN
78 # define SET_ENDIAN(a,b) (-EINVAL)
79 #endif
80 #ifndef GET_TSC_CTL
81 # define GET_TSC_CTL(a) (-EINVAL)
82 #endif
83 #ifndef SET_TSC_CTL
84 # define SET_TSC_CTL(a) (-EINVAL)
85 #endif
86
87 /*
88 * this is where the system-wide overflow UID and GID are defined, for
89 * architectures that now have 32-bit UID/GID but didn't in the past
90 */
91
92 int overflowuid = DEFAULT_OVERFLOWUID;
93 int overflowgid = DEFAULT_OVERFLOWGID;
94
95 #ifdef CONFIG_UID16
96 EXPORT_SYMBOL(overflowuid);
97 EXPORT_SYMBOL(overflowgid);
98 #endif
99
100 /*
101 * the same as above, but for filesystems which can only store a 16-bit
102 * UID and GID. as such, this is needed on all architectures
103 */
104
105 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
106 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
107
108 EXPORT_SYMBOL(fs_overflowuid);
109 EXPORT_SYMBOL(fs_overflowgid);
110
111 /*
112 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
113 */
114
115 int C_A_D = 1;
116 struct pid *cad_pid;
117 EXPORT_SYMBOL(cad_pid);
118
119 /*
120 * If set, this is used for preparing the system to power off.
121 */
122
123 void (*pm_power_off_prepare)(void);
124
125 /*
126 * Returns true if current's euid is same as p's uid or euid,
127 * or has CAP_SYS_NICE to p's user_ns.
128 *
129 * Called with rcu_read_lock, creds are safe
130 */
131 static bool set_one_prio_perm(struct task_struct *p)
132 {
133 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
134
135 if (pcred->user->user_ns == cred->user->user_ns &&
136 (pcred->uid == cred->euid ||
137 pcred->euid == cred->euid))
138 return true;
139 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
140 return true;
141 return false;
142 }
143
144 /*
145 * set the priority of a task
146 * - the caller must hold the RCU read lock
147 */
148 static int set_one_prio(struct task_struct *p, int niceval, int error)
149 {
150 int no_nice;
151
152 if (!set_one_prio_perm(p)) {
153 error = -EPERM;
154 goto out;
155 }
156 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
157 error = -EACCES;
158 goto out;
159 }
160 no_nice = security_task_setnice(p, niceval);
161 if (no_nice) {
162 error = no_nice;
163 goto out;
164 }
165 if (error == -ESRCH)
166 error = 0;
167 set_user_nice(p, niceval);
168 out:
169 return error;
170 }
171
172 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
173 {
174 struct task_struct *g, *p;
175 struct user_struct *user;
176 const struct cred *cred = current_cred();
177 int error = -EINVAL;
178 struct pid *pgrp;
179
180 if (which > PRIO_USER || which < PRIO_PROCESS)
181 goto out;
182
183 /* normalize: avoid signed division (rounding problems) */
184 error = -ESRCH;
185 if (niceval < -20)
186 niceval = -20;
187 if (niceval > 19)
188 niceval = 19;
189
190 rcu_read_lock();
191 read_lock(&tasklist_lock);
192 switch (which) {
193 case PRIO_PROCESS:
194 if (who)
195 p = find_task_by_vpid(who);
196 else
197 p = current;
198 if (p)
199 error = set_one_prio(p, niceval, error);
200 break;
201 case PRIO_PGRP:
202 if (who)
203 pgrp = find_vpid(who);
204 else
205 pgrp = task_pgrp(current);
206 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
207 error = set_one_prio(p, niceval, error);
208 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
209 break;
210 case PRIO_USER:
211 user = (struct user_struct *) cred->user;
212 if (!who)
213 who = cred->uid;
214 else if ((who != cred->uid) &&
215 !(user = find_user(who)))
216 goto out_unlock; /* No processes for this user */
217
218 do_each_thread(g, p) {
219 if (__task_cred(p)->uid == who)
220 error = set_one_prio(p, niceval, error);
221 } while_each_thread(g, p);
222 if (who != cred->uid)
223 free_uid(user); /* For find_user() */
224 break;
225 }
226 out_unlock:
227 read_unlock(&tasklist_lock);
228 rcu_read_unlock();
229 out:
230 return error;
231 }
232
233 /*
234 * Ugh. To avoid negative return values, "getpriority()" will
235 * not return the normal nice-value, but a negated value that
236 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
237 * to stay compatible.
238 */
239 SYSCALL_DEFINE2(getpriority, int, which, int, who)
240 {
241 struct task_struct *g, *p;
242 struct user_struct *user;
243 const struct cred *cred = current_cred();
244 long niceval, retval = -ESRCH;
245 struct pid *pgrp;
246
247 if (which > PRIO_USER || which < PRIO_PROCESS)
248 return -EINVAL;
249
250 rcu_read_lock();
251 read_lock(&tasklist_lock);
252 switch (which) {
253 case PRIO_PROCESS:
254 if (who)
255 p = find_task_by_vpid(who);
256 else
257 p = current;
258 if (p) {
259 niceval = 20 - task_nice(p);
260 if (niceval > retval)
261 retval = niceval;
262 }
263 break;
264 case PRIO_PGRP:
265 if (who)
266 pgrp = find_vpid(who);
267 else
268 pgrp = task_pgrp(current);
269 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
270 niceval = 20 - task_nice(p);
271 if (niceval > retval)
272 retval = niceval;
273 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
274 break;
275 case PRIO_USER:
276 user = (struct user_struct *) cred->user;
277 if (!who)
278 who = cred->uid;
279 else if ((who != cred->uid) &&
280 !(user = find_user(who)))
281 goto out_unlock; /* No processes for this user */
282
283 do_each_thread(g, p) {
284 if (__task_cred(p)->uid == who) {
285 niceval = 20 - task_nice(p);
286 if (niceval > retval)
287 retval = niceval;
288 }
289 } while_each_thread(g, p);
290 if (who != cred->uid)
291 free_uid(user); /* for find_user() */
292 break;
293 }
294 out_unlock:
295 read_unlock(&tasklist_lock);
296 rcu_read_unlock();
297
298 return retval;
299 }
300
301 /**
302 * emergency_restart - reboot the system
303 *
304 * Without shutting down any hardware or taking any locks
305 * reboot the system. This is called when we know we are in
306 * trouble so this is our best effort to reboot. This is
307 * safe to call in interrupt context.
308 */
309 void emergency_restart(void)
310 {
311 kmsg_dump(KMSG_DUMP_EMERG);
312 machine_emergency_restart();
313 }
314 EXPORT_SYMBOL_GPL(emergency_restart);
315
316 void kernel_restart_prepare(char *cmd)
317 {
318 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
319 system_state = SYSTEM_RESTART;
320 usermodehelper_disable();
321 device_shutdown();
322 syscore_shutdown();
323 }
324
325 /**
326 * register_reboot_notifier - Register function to be called at reboot time
327 * @nb: Info about notifier function to be called
328 *
329 * Registers a function with the list of functions
330 * to be called at reboot time.
331 *
332 * Currently always returns zero, as blocking_notifier_chain_register()
333 * always returns zero.
334 */
335 int register_reboot_notifier(struct notifier_block *nb)
336 {
337 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
338 }
339 EXPORT_SYMBOL(register_reboot_notifier);
340
341 /**
342 * unregister_reboot_notifier - Unregister previously registered reboot notifier
343 * @nb: Hook to be unregistered
344 *
345 * Unregisters a previously registered reboot
346 * notifier function.
347 *
348 * Returns zero on success, or %-ENOENT on failure.
349 */
350 int unregister_reboot_notifier(struct notifier_block *nb)
351 {
352 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
353 }
354 EXPORT_SYMBOL(unregister_reboot_notifier);
355
356 /**
357 * kernel_restart - reboot the system
358 * @cmd: pointer to buffer containing command to execute for restart
359 * or %NULL
360 *
361 * Shutdown everything and perform a clean reboot.
362 * This is not safe to call in interrupt context.
363 */
364 void kernel_restart(char *cmd)
365 {
366 kernel_restart_prepare(cmd);
367 if (!cmd)
368 printk(KERN_EMERG "Restarting system.\n");
369 else
370 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
371 kmsg_dump(KMSG_DUMP_RESTART);
372 machine_restart(cmd);
373 }
374 EXPORT_SYMBOL_GPL(kernel_restart);
375
376 static void kernel_shutdown_prepare(enum system_states state)
377 {
378 blocking_notifier_call_chain(&reboot_notifier_list,
379 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
380 system_state = state;
381 usermodehelper_disable();
382 device_shutdown();
383 }
384 /**
385 * kernel_halt - halt the system
386 *
387 * Shutdown everything and perform a clean system halt.
388 */
389 void kernel_halt(void)
390 {
391 kernel_shutdown_prepare(SYSTEM_HALT);
392 syscore_shutdown();
393 printk(KERN_EMERG "System halted.\n");
394 kmsg_dump(KMSG_DUMP_HALT);
395 machine_halt();
396 }
397
398 EXPORT_SYMBOL_GPL(kernel_halt);
399
400 /**
401 * kernel_power_off - power_off the system
402 *
403 * Shutdown everything and perform a clean system power_off.
404 */
405 void kernel_power_off(void)
406 {
407 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
408 if (pm_power_off_prepare)
409 pm_power_off_prepare();
410 disable_nonboot_cpus();
411 syscore_shutdown();
412 printk(KERN_EMERG "Power down.\n");
413 kmsg_dump(KMSG_DUMP_POWEROFF);
414 machine_power_off();
415 }
416 EXPORT_SYMBOL_GPL(kernel_power_off);
417
418 static DEFINE_MUTEX(reboot_mutex);
419
420 /*
421 * Reboot system call: for obvious reasons only root may call it,
422 * and even root needs to set up some magic numbers in the registers
423 * so that some mistake won't make this reboot the whole machine.
424 * You can also set the meaning of the ctrl-alt-del-key here.
425 *
426 * reboot doesn't sync: do that yourself before calling this.
427 */
428 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
429 void __user *, arg)
430 {
431 char buffer[256];
432 int ret = 0;
433
434 /* We only trust the superuser with rebooting the system. */
435 if (!capable(CAP_SYS_BOOT))
436 return -EPERM;
437
438 /* For safety, we require "magic" arguments. */
439 if (magic1 != LINUX_REBOOT_MAGIC1 ||
440 (magic2 != LINUX_REBOOT_MAGIC2 &&
441 magic2 != LINUX_REBOOT_MAGIC2A &&
442 magic2 != LINUX_REBOOT_MAGIC2B &&
443 magic2 != LINUX_REBOOT_MAGIC2C))
444 return -EINVAL;
445
446 /* Instead of trying to make the power_off code look like
447 * halt when pm_power_off is not set do it the easy way.
448 */
449 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
450 cmd = LINUX_REBOOT_CMD_HALT;
451
452 mutex_lock(&reboot_mutex);
453 switch (cmd) {
454 case LINUX_REBOOT_CMD_RESTART:
455 kernel_restart(NULL);
456 break;
457
458 case LINUX_REBOOT_CMD_CAD_ON:
459 C_A_D = 1;
460 break;
461
462 case LINUX_REBOOT_CMD_CAD_OFF:
463 C_A_D = 0;
464 break;
465
466 case LINUX_REBOOT_CMD_HALT:
467 kernel_halt();
468 do_exit(0);
469 panic("cannot halt");
470
471 case LINUX_REBOOT_CMD_POWER_OFF:
472 kernel_power_off();
473 do_exit(0);
474 break;
475
476 case LINUX_REBOOT_CMD_RESTART2:
477 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
478 ret = -EFAULT;
479 break;
480 }
481 buffer[sizeof(buffer) - 1] = '\0';
482
483 kernel_restart(buffer);
484 break;
485
486 #ifdef CONFIG_KEXEC
487 case LINUX_REBOOT_CMD_KEXEC:
488 ret = kernel_kexec();
489 break;
490 #endif
491
492 #ifdef CONFIG_HIBERNATION
493 case LINUX_REBOOT_CMD_SW_SUSPEND:
494 ret = hibernate();
495 break;
496 #endif
497
498 default:
499 ret = -EINVAL;
500 break;
501 }
502 mutex_unlock(&reboot_mutex);
503 return ret;
504 }
505
506 static void deferred_cad(struct work_struct *dummy)
507 {
508 kernel_restart(NULL);
509 }
510
511 /*
512 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
513 * As it's called within an interrupt, it may NOT sync: the only choice
514 * is whether to reboot at once, or just ignore the ctrl-alt-del.
515 */
516 void ctrl_alt_del(void)
517 {
518 static DECLARE_WORK(cad_work, deferred_cad);
519
520 if (C_A_D)
521 schedule_work(&cad_work);
522 else
523 kill_cad_pid(SIGINT, 1);
524 }
525
526 /*
527 * Unprivileged users may change the real gid to the effective gid
528 * or vice versa. (BSD-style)
529 *
530 * If you set the real gid at all, or set the effective gid to a value not
531 * equal to the real gid, then the saved gid is set to the new effective gid.
532 *
533 * This makes it possible for a setgid program to completely drop its
534 * privileges, which is often a useful assertion to make when you are doing
535 * a security audit over a program.
536 *
537 * The general idea is that a program which uses just setregid() will be
538 * 100% compatible with BSD. A program which uses just setgid() will be
539 * 100% compatible with POSIX with saved IDs.
540 *
541 * SMP: There are not races, the GIDs are checked only by filesystem
542 * operations (as far as semantic preservation is concerned).
543 */
544 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
545 {
546 const struct cred *old;
547 struct cred *new;
548 int retval;
549
550 new = prepare_creds();
551 if (!new)
552 return -ENOMEM;
553 old = current_cred();
554
555 retval = -EPERM;
556 if (rgid != (gid_t) -1) {
557 if (old->gid == rgid ||
558 old->egid == rgid ||
559 nsown_capable(CAP_SETGID))
560 new->gid = rgid;
561 else
562 goto error;
563 }
564 if (egid != (gid_t) -1) {
565 if (old->gid == egid ||
566 old->egid == egid ||
567 old->sgid == egid ||
568 nsown_capable(CAP_SETGID))
569 new->egid = egid;
570 else
571 goto error;
572 }
573
574 if (rgid != (gid_t) -1 ||
575 (egid != (gid_t) -1 && egid != old->gid))
576 new->sgid = new->egid;
577 new->fsgid = new->egid;
578
579 return commit_creds(new);
580
581 error:
582 abort_creds(new);
583 return retval;
584 }
585
586 /*
587 * setgid() is implemented like SysV w/ SAVED_IDS
588 *
589 * SMP: Same implicit races as above.
590 */
591 SYSCALL_DEFINE1(setgid, gid_t, gid)
592 {
593 const struct cred *old;
594 struct cred *new;
595 int retval;
596
597 new = prepare_creds();
598 if (!new)
599 return -ENOMEM;
600 old = current_cred();
601
602 retval = -EPERM;
603 if (nsown_capable(CAP_SETGID))
604 new->gid = new->egid = new->sgid = new->fsgid = gid;
605 else if (gid == old->gid || gid == old->sgid)
606 new->egid = new->fsgid = gid;
607 else
608 goto error;
609
610 return commit_creds(new);
611
612 error:
613 abort_creds(new);
614 return retval;
615 }
616
617 /*
618 * change the user struct in a credentials set to match the new UID
619 */
620 static int set_user(struct cred *new)
621 {
622 struct user_struct *new_user;
623
624 new_user = alloc_uid(current_user_ns(), new->uid);
625 if (!new_user)
626 return -EAGAIN;
627
628 /*
629 * We don't fail in case of NPROC limit excess here because too many
630 * poorly written programs don't check set*uid() return code, assuming
631 * it never fails if called by root. We may still enforce NPROC limit
632 * for programs doing set*uid()+execve() by harmlessly deferring the
633 * failure to the execve() stage.
634 */
635 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
636 new_user != INIT_USER)
637 current->flags |= PF_NPROC_EXCEEDED;
638 else
639 current->flags &= ~PF_NPROC_EXCEEDED;
640
641 free_uid(new->user);
642 new->user = new_user;
643 return 0;
644 }
645
646 /*
647 * Unprivileged users may change the real uid to the effective uid
648 * or vice versa. (BSD-style)
649 *
650 * If you set the real uid at all, or set the effective uid to a value not
651 * equal to the real uid, then the saved uid is set to the new effective uid.
652 *
653 * This makes it possible for a setuid program to completely drop its
654 * privileges, which is often a useful assertion to make when you are doing
655 * a security audit over a program.
656 *
657 * The general idea is that a program which uses just setreuid() will be
658 * 100% compatible with BSD. A program which uses just setuid() will be
659 * 100% compatible with POSIX with saved IDs.
660 */
661 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
662 {
663 const struct cred *old;
664 struct cred *new;
665 int retval;
666
667 new = prepare_creds();
668 if (!new)
669 return -ENOMEM;
670 old = current_cred();
671
672 retval = -EPERM;
673 if (ruid != (uid_t) -1) {
674 new->uid = ruid;
675 if (old->uid != ruid &&
676 old->euid != ruid &&
677 !nsown_capable(CAP_SETUID))
678 goto error;
679 }
680
681 if (euid != (uid_t) -1) {
682 new->euid = euid;
683 if (old->uid != euid &&
684 old->euid != euid &&
685 old->suid != euid &&
686 !nsown_capable(CAP_SETUID))
687 goto error;
688 }
689
690 if (new->uid != old->uid) {
691 retval = set_user(new);
692 if (retval < 0)
693 goto error;
694 }
695 if (ruid != (uid_t) -1 ||
696 (euid != (uid_t) -1 && euid != old->uid))
697 new->suid = new->euid;
698 new->fsuid = new->euid;
699
700 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
701 if (retval < 0)
702 goto error;
703
704 return commit_creds(new);
705
706 error:
707 abort_creds(new);
708 return retval;
709 }
710
711 /*
712 * setuid() is implemented like SysV with SAVED_IDS
713 *
714 * Note that SAVED_ID's is deficient in that a setuid root program
715 * like sendmail, for example, cannot set its uid to be a normal
716 * user and then switch back, because if you're root, setuid() sets
717 * the saved uid too. If you don't like this, blame the bright people
718 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
719 * will allow a root program to temporarily drop privileges and be able to
720 * regain them by swapping the real and effective uid.
721 */
722 SYSCALL_DEFINE1(setuid, uid_t, uid)
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 old = current_cred();
732
733 retval = -EPERM;
734 if (nsown_capable(CAP_SETUID)) {
735 new->suid = new->uid = uid;
736 if (uid != old->uid) {
737 retval = set_user(new);
738 if (retval < 0)
739 goto error;
740 }
741 } else if (uid != old->uid && uid != new->suid) {
742 goto error;
743 }
744
745 new->fsuid = new->euid = uid;
746
747 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
748 if (retval < 0)
749 goto error;
750
751 return commit_creds(new);
752
753 error:
754 abort_creds(new);
755 return retval;
756 }
757
758
759 /*
760 * This function implements a generic ability to update ruid, euid,
761 * and suid. This allows you to implement the 4.4 compatible seteuid().
762 */
763 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
764 {
765 const struct cred *old;
766 struct cred *new;
767 int retval;
768
769 new = prepare_creds();
770 if (!new)
771 return -ENOMEM;
772
773 old = current_cred();
774
775 retval = -EPERM;
776 if (!nsown_capable(CAP_SETUID)) {
777 if (ruid != (uid_t) -1 && ruid != old->uid &&
778 ruid != old->euid && ruid != old->suid)
779 goto error;
780 if (euid != (uid_t) -1 && euid != old->uid &&
781 euid != old->euid && euid != old->suid)
782 goto error;
783 if (suid != (uid_t) -1 && suid != old->uid &&
784 suid != old->euid && suid != old->suid)
785 goto error;
786 }
787
788 if (ruid != (uid_t) -1) {
789 new->uid = ruid;
790 if (ruid != old->uid) {
791 retval = set_user(new);
792 if (retval < 0)
793 goto error;
794 }
795 }
796 if (euid != (uid_t) -1)
797 new->euid = euid;
798 if (suid != (uid_t) -1)
799 new->suid = suid;
800 new->fsuid = new->euid;
801
802 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
803 if (retval < 0)
804 goto error;
805
806 return commit_creds(new);
807
808 error:
809 abort_creds(new);
810 return retval;
811 }
812
813 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
814 {
815 const struct cred *cred = current_cred();
816 int retval;
817
818 if (!(retval = put_user(cred->uid, ruid)) &&
819 !(retval = put_user(cred->euid, euid)))
820 retval = put_user(cred->suid, suid);
821
822 return retval;
823 }
824
825 /*
826 * Same as above, but for rgid, egid, sgid.
827 */
828 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
829 {
830 const struct cred *old;
831 struct cred *new;
832 int retval;
833
834 new = prepare_creds();
835 if (!new)
836 return -ENOMEM;
837 old = current_cred();
838
839 retval = -EPERM;
840 if (!nsown_capable(CAP_SETGID)) {
841 if (rgid != (gid_t) -1 && rgid != old->gid &&
842 rgid != old->egid && rgid != old->sgid)
843 goto error;
844 if (egid != (gid_t) -1 && egid != old->gid &&
845 egid != old->egid && egid != old->sgid)
846 goto error;
847 if (sgid != (gid_t) -1 && sgid != old->gid &&
848 sgid != old->egid && sgid != old->sgid)
849 goto error;
850 }
851
852 if (rgid != (gid_t) -1)
853 new->gid = rgid;
854 if (egid != (gid_t) -1)
855 new->egid = egid;
856 if (sgid != (gid_t) -1)
857 new->sgid = sgid;
858 new->fsgid = new->egid;
859
860 return commit_creds(new);
861
862 error:
863 abort_creds(new);
864 return retval;
865 }
866
867 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
868 {
869 const struct cred *cred = current_cred();
870 int retval;
871
872 if (!(retval = put_user(cred->gid, rgid)) &&
873 !(retval = put_user(cred->egid, egid)))
874 retval = put_user(cred->sgid, sgid);
875
876 return retval;
877 }
878
879
880 /*
881 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
882 * is used for "access()" and for the NFS daemon (letting nfsd stay at
883 * whatever uid it wants to). It normally shadows "euid", except when
884 * explicitly set by setfsuid() or for access..
885 */
886 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
887 {
888 const struct cred *old;
889 struct cred *new;
890 uid_t old_fsuid;
891
892 new = prepare_creds();
893 if (!new)
894 return current_fsuid();
895 old = current_cred();
896 old_fsuid = old->fsuid;
897
898 if (uid == old->uid || uid == old->euid ||
899 uid == old->suid || uid == old->fsuid ||
900 nsown_capable(CAP_SETUID)) {
901 if (uid != old_fsuid) {
902 new->fsuid = uid;
903 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
904 goto change_okay;
905 }
906 }
907
908 abort_creds(new);
909 return old_fsuid;
910
911 change_okay:
912 commit_creds(new);
913 return old_fsuid;
914 }
915
916 /*
917 * Samma på svenska..
918 */
919 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
920 {
921 const struct cred *old;
922 struct cred *new;
923 gid_t old_fsgid;
924
925 new = prepare_creds();
926 if (!new)
927 return current_fsgid();
928 old = current_cred();
929 old_fsgid = old->fsgid;
930
931 if (gid == old->gid || gid == old->egid ||
932 gid == old->sgid || gid == old->fsgid ||
933 nsown_capable(CAP_SETGID)) {
934 if (gid != old_fsgid) {
935 new->fsgid = gid;
936 goto change_okay;
937 }
938 }
939
940 abort_creds(new);
941 return old_fsgid;
942
943 change_okay:
944 commit_creds(new);
945 return old_fsgid;
946 }
947
948 void do_sys_times(struct tms *tms)
949 {
950 cputime_t tgutime, tgstime, cutime, cstime;
951
952 spin_lock_irq(&current->sighand->siglock);
953 thread_group_times(current, &tgutime, &tgstime);
954 cutime = current->signal->cutime;
955 cstime = current->signal->cstime;
956 spin_unlock_irq(&current->sighand->siglock);
957 tms->tms_utime = cputime_to_clock_t(tgutime);
958 tms->tms_stime = cputime_to_clock_t(tgstime);
959 tms->tms_cutime = cputime_to_clock_t(cutime);
960 tms->tms_cstime = cputime_to_clock_t(cstime);
961 }
962
963 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
964 {
965 if (tbuf) {
966 struct tms tmp;
967
968 do_sys_times(&tmp);
969 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
970 return -EFAULT;
971 }
972 force_successful_syscall_return();
973 return (long) jiffies_64_to_clock_t(get_jiffies_64());
974 }
975
976 /*
977 * This needs some heavy checking ...
978 * I just haven't the stomach for it. I also don't fully
979 * understand sessions/pgrp etc. Let somebody who does explain it.
980 *
981 * OK, I think I have the protection semantics right.... this is really
982 * only important on a multi-user system anyway, to make sure one user
983 * can't send a signal to a process owned by another. -TYT, 12/12/91
984 *
985 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
986 * LBT 04.03.94
987 */
988 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
989 {
990 struct task_struct *p;
991 struct task_struct *group_leader = current->group_leader;
992 struct pid *pgrp;
993 int err;
994
995 if (!pid)
996 pid = task_pid_vnr(group_leader);
997 if (!pgid)
998 pgid = pid;
999 if (pgid < 0)
1000 return -EINVAL;
1001 rcu_read_lock();
1002
1003 /* From this point forward we keep holding onto the tasklist lock
1004 * so that our parent does not change from under us. -DaveM
1005 */
1006 write_lock_irq(&tasklist_lock);
1007
1008 err = -ESRCH;
1009 p = find_task_by_vpid(pid);
1010 if (!p)
1011 goto out;
1012
1013 err = -EINVAL;
1014 if (!thread_group_leader(p))
1015 goto out;
1016
1017 if (same_thread_group(p->real_parent, group_leader)) {
1018 err = -EPERM;
1019 if (task_session(p) != task_session(group_leader))
1020 goto out;
1021 err = -EACCES;
1022 if (p->did_exec)
1023 goto out;
1024 } else {
1025 err = -ESRCH;
1026 if (p != group_leader)
1027 goto out;
1028 }
1029
1030 err = -EPERM;
1031 if (p->signal->leader)
1032 goto out;
1033
1034 pgrp = task_pid(p);
1035 if (pgid != pid) {
1036 struct task_struct *g;
1037
1038 pgrp = find_vpid(pgid);
1039 g = pid_task(pgrp, PIDTYPE_PGID);
1040 if (!g || task_session(g) != task_session(group_leader))
1041 goto out;
1042 }
1043
1044 err = security_task_setpgid(p, pgid);
1045 if (err)
1046 goto out;
1047
1048 if (task_pgrp(p) != pgrp)
1049 change_pid(p, PIDTYPE_PGID, pgrp);
1050
1051 err = 0;
1052 out:
1053 /* All paths lead to here, thus we are safe. -DaveM */
1054 write_unlock_irq(&tasklist_lock);
1055 rcu_read_unlock();
1056 return err;
1057 }
1058
1059 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1060 {
1061 struct task_struct *p;
1062 struct pid *grp;
1063 int retval;
1064
1065 rcu_read_lock();
1066 if (!pid)
1067 grp = task_pgrp(current);
1068 else {
1069 retval = -ESRCH;
1070 p = find_task_by_vpid(pid);
1071 if (!p)
1072 goto out;
1073 grp = task_pgrp(p);
1074 if (!grp)
1075 goto out;
1076
1077 retval = security_task_getpgid(p);
1078 if (retval)
1079 goto out;
1080 }
1081 retval = pid_vnr(grp);
1082 out:
1083 rcu_read_unlock();
1084 return retval;
1085 }
1086
1087 #ifdef __ARCH_WANT_SYS_GETPGRP
1088
1089 SYSCALL_DEFINE0(getpgrp)
1090 {
1091 return sys_getpgid(0);
1092 }
1093
1094 #endif
1095
1096 SYSCALL_DEFINE1(getsid, pid_t, pid)
1097 {
1098 struct task_struct *p;
1099 struct pid *sid;
1100 int retval;
1101
1102 rcu_read_lock();
1103 if (!pid)
1104 sid = task_session(current);
1105 else {
1106 retval = -ESRCH;
1107 p = find_task_by_vpid(pid);
1108 if (!p)
1109 goto out;
1110 sid = task_session(p);
1111 if (!sid)
1112 goto out;
1113
1114 retval = security_task_getsid(p);
1115 if (retval)
1116 goto out;
1117 }
1118 retval = pid_vnr(sid);
1119 out:
1120 rcu_read_unlock();
1121 return retval;
1122 }
1123
1124 SYSCALL_DEFINE0(setsid)
1125 {
1126 struct task_struct *group_leader = current->group_leader;
1127 struct pid *sid = task_pid(group_leader);
1128 pid_t session = pid_vnr(sid);
1129 int err = -EPERM;
1130
1131 write_lock_irq(&tasklist_lock);
1132 /* Fail if I am already a session leader */
1133 if (group_leader->signal->leader)
1134 goto out;
1135
1136 /* Fail if a process group id already exists that equals the
1137 * proposed session id.
1138 */
1139 if (pid_task(sid, PIDTYPE_PGID))
1140 goto out;
1141
1142 group_leader->signal->leader = 1;
1143 __set_special_pids(sid);
1144
1145 proc_clear_tty(group_leader);
1146
1147 err = session;
1148 out:
1149 write_unlock_irq(&tasklist_lock);
1150 if (err > 0) {
1151 proc_sid_connector(group_leader);
1152 sched_autogroup_create_attach(group_leader);
1153 }
1154 return err;
1155 }
1156
1157 DECLARE_RWSEM(uts_sem);
1158
1159 #ifdef COMPAT_UTS_MACHINE
1160 #define override_architecture(name) \
1161 (personality(current->personality) == PER_LINUX32 && \
1162 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1163 sizeof(COMPAT_UTS_MACHINE)))
1164 #else
1165 #define override_architecture(name) 0
1166 #endif
1167
1168 /*
1169 * Work around broken programs that cannot handle "Linux 3.0".
1170 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1171 */
1172 static int override_release(char __user *release, int len)
1173 {
1174 int ret = 0;
1175 char buf[len];
1176
1177 if (current->personality & UNAME26) {
1178 char *rest = UTS_RELEASE;
1179 int ndots = 0;
1180 unsigned v;
1181
1182 while (*rest) {
1183 if (*rest == '.' && ++ndots >= 3)
1184 break;
1185 if (!isdigit(*rest) && *rest != '.')
1186 break;
1187 rest++;
1188 }
1189 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1190 snprintf(buf, len, "2.6.%u%s", v, rest);
1191 ret = copy_to_user(release, buf, len);
1192 }
1193 return ret;
1194 }
1195
1196 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1197 {
1198 int errno = 0;
1199
1200 down_read(&uts_sem);
1201 if (copy_to_user(name, utsname(), sizeof *name))
1202 errno = -EFAULT;
1203 up_read(&uts_sem);
1204
1205 if (!errno && override_release(name->release, sizeof(name->release)))
1206 errno = -EFAULT;
1207 if (!errno && override_architecture(name))
1208 errno = -EFAULT;
1209 return errno;
1210 }
1211
1212 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1213 /*
1214 * Old cruft
1215 */
1216 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1217 {
1218 int error = 0;
1219
1220 if (!name)
1221 return -EFAULT;
1222
1223 down_read(&uts_sem);
1224 if (copy_to_user(name, utsname(), sizeof(*name)))
1225 error = -EFAULT;
1226 up_read(&uts_sem);
1227
1228 if (!error && override_release(name->release, sizeof(name->release)))
1229 error = -EFAULT;
1230 if (!error && override_architecture(name))
1231 error = -EFAULT;
1232 return error;
1233 }
1234
1235 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1236 {
1237 int error;
1238
1239 if (!name)
1240 return -EFAULT;
1241 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1242 return -EFAULT;
1243
1244 down_read(&uts_sem);
1245 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1246 __OLD_UTS_LEN);
1247 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1248 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1249 __OLD_UTS_LEN);
1250 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1251 error |= __copy_to_user(&name->release, &utsname()->release,
1252 __OLD_UTS_LEN);
1253 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1254 error |= __copy_to_user(&name->version, &utsname()->version,
1255 __OLD_UTS_LEN);
1256 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1257 error |= __copy_to_user(&name->machine, &utsname()->machine,
1258 __OLD_UTS_LEN);
1259 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1260 up_read(&uts_sem);
1261
1262 if (!error && override_architecture(name))
1263 error = -EFAULT;
1264 if (!error && override_release(name->release, sizeof(name->release)))
1265 error = -EFAULT;
1266 return error ? -EFAULT : 0;
1267 }
1268 #endif
1269
1270 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1271 {
1272 int errno;
1273 char tmp[__NEW_UTS_LEN];
1274
1275 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1276 return -EPERM;
1277
1278 if (len < 0 || len > __NEW_UTS_LEN)
1279 return -EINVAL;
1280 down_write(&uts_sem);
1281 errno = -EFAULT;
1282 if (!copy_from_user(tmp, name, len)) {
1283 struct new_utsname *u = utsname();
1284
1285 memcpy(u->nodename, tmp, len);
1286 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1287 errno = 0;
1288 }
1289 up_write(&uts_sem);
1290 return errno;
1291 }
1292
1293 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1294
1295 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1296 {
1297 int i, errno;
1298 struct new_utsname *u;
1299
1300 if (len < 0)
1301 return -EINVAL;
1302 down_read(&uts_sem);
1303 u = utsname();
1304 i = 1 + strlen(u->nodename);
1305 if (i > len)
1306 i = len;
1307 errno = 0;
1308 if (copy_to_user(name, u->nodename, i))
1309 errno = -EFAULT;
1310 up_read(&uts_sem);
1311 return errno;
1312 }
1313
1314 #endif
1315
1316 /*
1317 * Only setdomainname; getdomainname can be implemented by calling
1318 * uname()
1319 */
1320 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1321 {
1322 int errno;
1323 char tmp[__NEW_UTS_LEN];
1324
1325 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1326 return -EPERM;
1327 if (len < 0 || len > __NEW_UTS_LEN)
1328 return -EINVAL;
1329
1330 down_write(&uts_sem);
1331 errno = -EFAULT;
1332 if (!copy_from_user(tmp, name, len)) {
1333 struct new_utsname *u = utsname();
1334
1335 memcpy(u->domainname, tmp, len);
1336 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1337 errno = 0;
1338 }
1339 up_write(&uts_sem);
1340 return errno;
1341 }
1342
1343 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1344 {
1345 struct rlimit value;
1346 int ret;
1347
1348 ret = do_prlimit(current, resource, NULL, &value);
1349 if (!ret)
1350 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1351
1352 return ret;
1353 }
1354
1355 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1356
1357 /*
1358 * Back compatibility for getrlimit. Needed for some apps.
1359 */
1360
1361 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1362 struct rlimit __user *, rlim)
1363 {
1364 struct rlimit x;
1365 if (resource >= RLIM_NLIMITS)
1366 return -EINVAL;
1367
1368 task_lock(current->group_leader);
1369 x = current->signal->rlim[resource];
1370 task_unlock(current->group_leader);
1371 if (x.rlim_cur > 0x7FFFFFFF)
1372 x.rlim_cur = 0x7FFFFFFF;
1373 if (x.rlim_max > 0x7FFFFFFF)
1374 x.rlim_max = 0x7FFFFFFF;
1375 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1376 }
1377
1378 #endif
1379
1380 static inline bool rlim64_is_infinity(__u64 rlim64)
1381 {
1382 #if BITS_PER_LONG < 64
1383 return rlim64 >= ULONG_MAX;
1384 #else
1385 return rlim64 == RLIM64_INFINITY;
1386 #endif
1387 }
1388
1389 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1390 {
1391 if (rlim->rlim_cur == RLIM_INFINITY)
1392 rlim64->rlim_cur = RLIM64_INFINITY;
1393 else
1394 rlim64->rlim_cur = rlim->rlim_cur;
1395 if (rlim->rlim_max == RLIM_INFINITY)
1396 rlim64->rlim_max = RLIM64_INFINITY;
1397 else
1398 rlim64->rlim_max = rlim->rlim_max;
1399 }
1400
1401 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1402 {
1403 if (rlim64_is_infinity(rlim64->rlim_cur))
1404 rlim->rlim_cur = RLIM_INFINITY;
1405 else
1406 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1407 if (rlim64_is_infinity(rlim64->rlim_max))
1408 rlim->rlim_max = RLIM_INFINITY;
1409 else
1410 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1411 }
1412
1413 /* make sure you are allowed to change @tsk limits before calling this */
1414 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1415 struct rlimit *new_rlim, struct rlimit *old_rlim)
1416 {
1417 struct rlimit *rlim;
1418 int retval = 0;
1419
1420 if (resource >= RLIM_NLIMITS)
1421 return -EINVAL;
1422 if (new_rlim) {
1423 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1424 return -EINVAL;
1425 if (resource == RLIMIT_NOFILE &&
1426 new_rlim->rlim_max > sysctl_nr_open)
1427 return -EPERM;
1428 }
1429
1430 /* protect tsk->signal and tsk->sighand from disappearing */
1431 read_lock(&tasklist_lock);
1432 if (!tsk->sighand) {
1433 retval = -ESRCH;
1434 goto out;
1435 }
1436
1437 rlim = tsk->signal->rlim + resource;
1438 task_lock(tsk->group_leader);
1439 if (new_rlim) {
1440 /* Keep the capable check against init_user_ns until
1441 cgroups can contain all limits */
1442 if (new_rlim->rlim_max > rlim->rlim_max &&
1443 !capable(CAP_SYS_RESOURCE))
1444 retval = -EPERM;
1445 if (!retval)
1446 retval = security_task_setrlimit(tsk->group_leader,
1447 resource, new_rlim);
1448 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1449 /*
1450 * The caller is asking for an immediate RLIMIT_CPU
1451 * expiry. But we use the zero value to mean "it was
1452 * never set". So let's cheat and make it one second
1453 * instead
1454 */
1455 new_rlim->rlim_cur = 1;
1456 }
1457 }
1458 if (!retval) {
1459 if (old_rlim)
1460 *old_rlim = *rlim;
1461 if (new_rlim)
1462 *rlim = *new_rlim;
1463 }
1464 task_unlock(tsk->group_leader);
1465
1466 /*
1467 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1468 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1469 * very long-standing error, and fixing it now risks breakage of
1470 * applications, so we live with it
1471 */
1472 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1473 new_rlim->rlim_cur != RLIM_INFINITY)
1474 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1475 out:
1476 read_unlock(&tasklist_lock);
1477 return retval;
1478 }
1479
1480 /* rcu lock must be held */
1481 static int check_prlimit_permission(struct task_struct *task)
1482 {
1483 const struct cred *cred = current_cred(), *tcred;
1484
1485 if (current == task)
1486 return 0;
1487
1488 tcred = __task_cred(task);
1489 if (cred->user->user_ns == tcred->user->user_ns &&
1490 (cred->uid == tcred->euid &&
1491 cred->uid == tcred->suid &&
1492 cred->uid == tcred->uid &&
1493 cred->gid == tcred->egid &&
1494 cred->gid == tcred->sgid &&
1495 cred->gid == tcred->gid))
1496 return 0;
1497 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1498 return 0;
1499
1500 return -EPERM;
1501 }
1502
1503 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1504 const struct rlimit64 __user *, new_rlim,
1505 struct rlimit64 __user *, old_rlim)
1506 {
1507 struct rlimit64 old64, new64;
1508 struct rlimit old, new;
1509 struct task_struct *tsk;
1510 int ret;
1511
1512 if (new_rlim) {
1513 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1514 return -EFAULT;
1515 rlim64_to_rlim(&new64, &new);
1516 }
1517
1518 rcu_read_lock();
1519 tsk = pid ? find_task_by_vpid(pid) : current;
1520 if (!tsk) {
1521 rcu_read_unlock();
1522 return -ESRCH;
1523 }
1524 ret = check_prlimit_permission(tsk);
1525 if (ret) {
1526 rcu_read_unlock();
1527 return ret;
1528 }
1529 get_task_struct(tsk);
1530 rcu_read_unlock();
1531
1532 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1533 old_rlim ? &old : NULL);
1534
1535 if (!ret && old_rlim) {
1536 rlim_to_rlim64(&old, &old64);
1537 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1538 ret = -EFAULT;
1539 }
1540
1541 put_task_struct(tsk);
1542 return ret;
1543 }
1544
1545 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1546 {
1547 struct rlimit new_rlim;
1548
1549 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1550 return -EFAULT;
1551 return do_prlimit(current, resource, &new_rlim, NULL);
1552 }
1553
1554 /*
1555 * It would make sense to put struct rusage in the task_struct,
1556 * except that would make the task_struct be *really big*. After
1557 * task_struct gets moved into malloc'ed memory, it would
1558 * make sense to do this. It will make moving the rest of the information
1559 * a lot simpler! (Which we're not doing right now because we're not
1560 * measuring them yet).
1561 *
1562 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1563 * races with threads incrementing their own counters. But since word
1564 * reads are atomic, we either get new values or old values and we don't
1565 * care which for the sums. We always take the siglock to protect reading
1566 * the c* fields from p->signal from races with exit.c updating those
1567 * fields when reaping, so a sample either gets all the additions of a
1568 * given child after it's reaped, or none so this sample is before reaping.
1569 *
1570 * Locking:
1571 * We need to take the siglock for CHILDEREN, SELF and BOTH
1572 * for the cases current multithreaded, non-current single threaded
1573 * non-current multithreaded. Thread traversal is now safe with
1574 * the siglock held.
1575 * Strictly speaking, we donot need to take the siglock if we are current and
1576 * single threaded, as no one else can take our signal_struct away, no one
1577 * else can reap the children to update signal->c* counters, and no one else
1578 * can race with the signal-> fields. If we do not take any lock, the
1579 * signal-> fields could be read out of order while another thread was just
1580 * exiting. So we should place a read memory barrier when we avoid the lock.
1581 * On the writer side, write memory barrier is implied in __exit_signal
1582 * as __exit_signal releases the siglock spinlock after updating the signal->
1583 * fields. But we don't do this yet to keep things simple.
1584 *
1585 */
1586
1587 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1588 {
1589 r->ru_nvcsw += t->nvcsw;
1590 r->ru_nivcsw += t->nivcsw;
1591 r->ru_minflt += t->min_flt;
1592 r->ru_majflt += t->maj_flt;
1593 r->ru_inblock += task_io_get_inblock(t);
1594 r->ru_oublock += task_io_get_oublock(t);
1595 }
1596
1597 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1598 {
1599 struct task_struct *t;
1600 unsigned long flags;
1601 cputime_t tgutime, tgstime, utime, stime;
1602 unsigned long maxrss = 0;
1603
1604 memset((char *) r, 0, sizeof *r);
1605 utime = stime = cputime_zero;
1606
1607 if (who == RUSAGE_THREAD) {
1608 task_times(current, &utime, &stime);
1609 accumulate_thread_rusage(p, r);
1610 maxrss = p->signal->maxrss;
1611 goto out;
1612 }
1613
1614 if (!lock_task_sighand(p, &flags))
1615 return;
1616
1617 switch (who) {
1618 case RUSAGE_BOTH:
1619 case RUSAGE_CHILDREN:
1620 utime = p->signal->cutime;
1621 stime = p->signal->cstime;
1622 r->ru_nvcsw = p->signal->cnvcsw;
1623 r->ru_nivcsw = p->signal->cnivcsw;
1624 r->ru_minflt = p->signal->cmin_flt;
1625 r->ru_majflt = p->signal->cmaj_flt;
1626 r->ru_inblock = p->signal->cinblock;
1627 r->ru_oublock = p->signal->coublock;
1628 maxrss = p->signal->cmaxrss;
1629
1630 if (who == RUSAGE_CHILDREN)
1631 break;
1632
1633 case RUSAGE_SELF:
1634 thread_group_times(p, &tgutime, &tgstime);
1635 utime = cputime_add(utime, tgutime);
1636 stime = cputime_add(stime, tgstime);
1637 r->ru_nvcsw += p->signal->nvcsw;
1638 r->ru_nivcsw += p->signal->nivcsw;
1639 r->ru_minflt += p->signal->min_flt;
1640 r->ru_majflt += p->signal->maj_flt;
1641 r->ru_inblock += p->signal->inblock;
1642 r->ru_oublock += p->signal->oublock;
1643 if (maxrss < p->signal->maxrss)
1644 maxrss = p->signal->maxrss;
1645 t = p;
1646 do {
1647 accumulate_thread_rusage(t, r);
1648 t = next_thread(t);
1649 } while (t != p);
1650 break;
1651
1652 default:
1653 BUG();
1654 }
1655 unlock_task_sighand(p, &flags);
1656
1657 out:
1658 cputime_to_timeval(utime, &r->ru_utime);
1659 cputime_to_timeval(stime, &r->ru_stime);
1660
1661 if (who != RUSAGE_CHILDREN) {
1662 struct mm_struct *mm = get_task_mm(p);
1663 if (mm) {
1664 setmax_mm_hiwater_rss(&maxrss, mm);
1665 mmput(mm);
1666 }
1667 }
1668 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1669 }
1670
1671 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1672 {
1673 struct rusage r;
1674 k_getrusage(p, who, &r);
1675 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1676 }
1677
1678 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1679 {
1680 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1681 who != RUSAGE_THREAD)
1682 return -EINVAL;
1683 return getrusage(current, who, ru);
1684 }
1685
1686 SYSCALL_DEFINE1(umask, int, mask)
1687 {
1688 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1689 return mask;
1690 }
1691
1692 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1693 unsigned long, arg4, unsigned long, arg5)
1694 {
1695 struct task_struct *me = current;
1696 unsigned char comm[sizeof(me->comm)];
1697 long error;
1698
1699 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1700 if (error != -ENOSYS)
1701 return error;
1702
1703 error = 0;
1704 switch (option) {
1705 case PR_SET_PDEATHSIG:
1706 if (!valid_signal(arg2)) {
1707 error = -EINVAL;
1708 break;
1709 }
1710 me->pdeath_signal = arg2;
1711 error = 0;
1712 break;
1713 case PR_GET_PDEATHSIG:
1714 error = put_user(me->pdeath_signal, (int __user *)arg2);
1715 break;
1716 case PR_GET_DUMPABLE:
1717 error = get_dumpable(me->mm);
1718 break;
1719 case PR_SET_DUMPABLE:
1720 if (arg2 < 0 || arg2 > 1) {
1721 error = -EINVAL;
1722 break;
1723 }
1724 set_dumpable(me->mm, arg2);
1725 error = 0;
1726 break;
1727
1728 case PR_SET_UNALIGN:
1729 error = SET_UNALIGN_CTL(me, arg2);
1730 break;
1731 case PR_GET_UNALIGN:
1732 error = GET_UNALIGN_CTL(me, arg2);
1733 break;
1734 case PR_SET_FPEMU:
1735 error = SET_FPEMU_CTL(me, arg2);
1736 break;
1737 case PR_GET_FPEMU:
1738 error = GET_FPEMU_CTL(me, arg2);
1739 break;
1740 case PR_SET_FPEXC:
1741 error = SET_FPEXC_CTL(me, arg2);
1742 break;
1743 case PR_GET_FPEXC:
1744 error = GET_FPEXC_CTL(me, arg2);
1745 break;
1746 case PR_GET_TIMING:
1747 error = PR_TIMING_STATISTICAL;
1748 break;
1749 case PR_SET_TIMING:
1750 if (arg2 != PR_TIMING_STATISTICAL)
1751 error = -EINVAL;
1752 else
1753 error = 0;
1754 break;
1755
1756 case PR_SET_NAME:
1757 comm[sizeof(me->comm)-1] = 0;
1758 if (strncpy_from_user(comm, (char __user *)arg2,
1759 sizeof(me->comm) - 1) < 0)
1760 return -EFAULT;
1761 set_task_comm(me, comm);
1762 return 0;
1763 case PR_GET_NAME:
1764 get_task_comm(comm, me);
1765 if (copy_to_user((char __user *)arg2, comm,
1766 sizeof(comm)))
1767 return -EFAULT;
1768 return 0;
1769 case PR_GET_ENDIAN:
1770 error = GET_ENDIAN(me, arg2);
1771 break;
1772 case PR_SET_ENDIAN:
1773 error = SET_ENDIAN(me, arg2);
1774 break;
1775
1776 case PR_GET_SECCOMP:
1777 error = prctl_get_seccomp();
1778 break;
1779 case PR_SET_SECCOMP:
1780 error = prctl_set_seccomp(arg2);
1781 break;
1782 case PR_GET_TSC:
1783 error = GET_TSC_CTL(arg2);
1784 break;
1785 case PR_SET_TSC:
1786 error = SET_TSC_CTL(arg2);
1787 break;
1788 case PR_TASK_PERF_EVENTS_DISABLE:
1789 error = perf_event_task_disable();
1790 break;
1791 case PR_TASK_PERF_EVENTS_ENABLE:
1792 error = perf_event_task_enable();
1793 break;
1794 case PR_GET_TIMERSLACK:
1795 error = current->timer_slack_ns;
1796 break;
1797 case PR_SET_TIMERSLACK:
1798 if (arg2 <= 0)
1799 current->timer_slack_ns =
1800 current->default_timer_slack_ns;
1801 else
1802 current->timer_slack_ns = arg2;
1803 error = 0;
1804 break;
1805 case PR_MCE_KILL:
1806 if (arg4 | arg5)
1807 return -EINVAL;
1808 switch (arg2) {
1809 case PR_MCE_KILL_CLEAR:
1810 if (arg3 != 0)
1811 return -EINVAL;
1812 current->flags &= ~PF_MCE_PROCESS;
1813 break;
1814 case PR_MCE_KILL_SET:
1815 current->flags |= PF_MCE_PROCESS;
1816 if (arg3 == PR_MCE_KILL_EARLY)
1817 current->flags |= PF_MCE_EARLY;
1818 else if (arg3 == PR_MCE_KILL_LATE)
1819 current->flags &= ~PF_MCE_EARLY;
1820 else if (arg3 == PR_MCE_KILL_DEFAULT)
1821 current->flags &=
1822 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1823 else
1824 return -EINVAL;
1825 break;
1826 default:
1827 return -EINVAL;
1828 }
1829 error = 0;
1830 break;
1831 case PR_MCE_KILL_GET:
1832 if (arg2 | arg3 | arg4 | arg5)
1833 return -EINVAL;
1834 if (current->flags & PF_MCE_PROCESS)
1835 error = (current->flags & PF_MCE_EARLY) ?
1836 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1837 else
1838 error = PR_MCE_KILL_DEFAULT;
1839 break;
1840 default:
1841 error = -EINVAL;
1842 break;
1843 }
1844 return error;
1845 }
1846
1847 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1848 struct getcpu_cache __user *, unused)
1849 {
1850 int err = 0;
1851 int cpu = raw_smp_processor_id();
1852 if (cpup)
1853 err |= put_user(cpu, cpup);
1854 if (nodep)
1855 err |= put_user(cpu_to_node(cpu), nodep);
1856 return err ? -EFAULT : 0;
1857 }
1858
1859 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1860
1861 static void argv_cleanup(struct subprocess_info *info)
1862 {
1863 argv_free(info->argv);
1864 }
1865
1866 /**
1867 * orderly_poweroff - Trigger an orderly system poweroff
1868 * @force: force poweroff if command execution fails
1869 *
1870 * This may be called from any context to trigger a system shutdown.
1871 * If the orderly shutdown fails, it will force an immediate shutdown.
1872 */
1873 int orderly_poweroff(bool force)
1874 {
1875 int argc;
1876 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1877 static char *envp[] = {
1878 "HOME=/",
1879 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1880 NULL
1881 };
1882 int ret = -ENOMEM;
1883 struct subprocess_info *info;
1884
1885 if (argv == NULL) {
1886 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1887 __func__, poweroff_cmd);
1888 goto out;
1889 }
1890
1891 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1892 if (info == NULL) {
1893 argv_free(argv);
1894 goto out;
1895 }
1896
1897 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1898
1899 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1900
1901 out:
1902 if (ret && force) {
1903 printk(KERN_WARNING "Failed to start orderly shutdown: "
1904 "forcing the issue\n");
1905
1906 /* I guess this should try to kick off some daemon to
1907 sync and poweroff asap. Or not even bother syncing
1908 if we're doing an emergency shutdown? */
1909 emergency_sync();
1910 kernel_power_off();
1911 }
1912
1913 return ret;
1914 }
1915 EXPORT_SYMBOL_GPL(orderly_poweroff);
linux-next