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block: don't kick empty queue in blk_drain_queue()
[linux-2.6.git] / kernel / sys.c
blob481611fbd079a90094876bd2ef9743803fa45576
1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/export.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/kmod.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 #include <linux/version.h>
42 #include <linux/ctype.h>
43
44 #include <linux/compat.h>
45 #include <linux/syscalls.h>
46 #include <linux/kprobes.h>
47 #include <linux/user_namespace.h>
48
49 #include <linux/kmsg_dump.h>
50 /* Move somewhere else to avoid recompiling? */
51 #include <generated/utsrelease.h>
52
53 #include <asm/uaccess.h>
54 #include <asm/io.h>
55 #include <asm/unistd.h>
56
57 #ifndef SET_UNALIGN_CTL
58 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
59 #endif
60 #ifndef GET_UNALIGN_CTL
61 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
62 #endif
63 #ifndef SET_FPEMU_CTL
64 # define SET_FPEMU_CTL(a,b) (-EINVAL)
65 #endif
66 #ifndef GET_FPEMU_CTL
67 # define GET_FPEMU_CTL(a,b) (-EINVAL)
68 #endif
69 #ifndef SET_FPEXC_CTL
70 # define SET_FPEXC_CTL(a,b) (-EINVAL)
71 #endif
72 #ifndef GET_FPEXC_CTL
73 # define GET_FPEXC_CTL(a,b) (-EINVAL)
74 #endif
75 #ifndef GET_ENDIAN
76 # define GET_ENDIAN(a,b) (-EINVAL)
77 #endif
78 #ifndef SET_ENDIAN
79 # define SET_ENDIAN(a,b) (-EINVAL)
80 #endif
81 #ifndef GET_TSC_CTL
82 # define GET_TSC_CTL(a) (-EINVAL)
83 #endif
84 #ifndef SET_TSC_CTL
85 # define SET_TSC_CTL(a) (-EINVAL)
86 #endif
87
88 /*
89 * this is where the system-wide overflow UID and GID are defined, for
90 * architectures that now have 32-bit UID/GID but didn't in the past
91 */
92
93 int overflowuid = DEFAULT_OVERFLOWUID;
94 int overflowgid = DEFAULT_OVERFLOWGID;
95
96 #ifdef CONFIG_UID16
97 EXPORT_SYMBOL(overflowuid);
98 EXPORT_SYMBOL(overflowgid);
99 #endif
100
101 /*
102 * the same as above, but for filesystems which can only store a 16-bit
103 * UID and GID. as such, this is needed on all architectures
104 */
105
106 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
107 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
108
109 EXPORT_SYMBOL(fs_overflowuid);
110 EXPORT_SYMBOL(fs_overflowgid);
111
112 /*
113 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
114 */
115
116 int C_A_D = 1;
117 struct pid *cad_pid;
118 EXPORT_SYMBOL(cad_pid);
119
120 /*
121 * If set, this is used for preparing the system to power off.
122 */
123
124 void (*pm_power_off_prepare)(void);
125
126 /*
127 * Returns true if current's euid is same as p's uid or euid,
128 * or has CAP_SYS_NICE to p's user_ns.
129 *
130 * Called with rcu_read_lock, creds are safe
131 */
132 static bool set_one_prio_perm(struct task_struct *p)
133 {
134 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
135
136 if (pcred->user->user_ns == cred->user->user_ns &&
137 (pcred->uid == cred->euid ||
138 pcred->euid == cred->euid))
139 return true;
140 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
141 return true;
142 return false;
143 }
144
145 /*
146 * set the priority of a task
147 * - the caller must hold the RCU read lock
148 */
149 static int set_one_prio(struct task_struct *p, int niceval, int error)
150 {
151 int no_nice;
152
153 if (!set_one_prio_perm(p)) {
154 error = -EPERM;
155 goto out;
156 }
157 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
158 error = -EACCES;
159 goto out;
160 }
161 no_nice = security_task_setnice(p, niceval);
162 if (no_nice) {
163 error = no_nice;
164 goto out;
165 }
166 if (error == -ESRCH)
167 error = 0;
168 set_user_nice(p, niceval);
169 out:
170 return error;
171 }
172
173 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
174 {
175 struct task_struct *g, *p;
176 struct user_struct *user;
177 const struct cred *cred = current_cred();
178 int error = -EINVAL;
179 struct pid *pgrp;
180
181 if (which > PRIO_USER || which < PRIO_PROCESS)
182 goto out;
183
184 /* normalize: avoid signed division (rounding problems) */
185 error = -ESRCH;
186 if (niceval < -20)
187 niceval = -20;
188 if (niceval > 19)
189 niceval = 19;
190
191 rcu_read_lock();
192 read_lock(&tasklist_lock);
193 switch (which) {
194 case PRIO_PROCESS:
195 if (who)
196 p = find_task_by_vpid(who);
197 else
198 p = current;
199 if (p)
200 error = set_one_prio(p, niceval, error);
201 break;
202 case PRIO_PGRP:
203 if (who)
204 pgrp = find_vpid(who);
205 else
206 pgrp = task_pgrp(current);
207 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
208 error = set_one_prio(p, niceval, error);
209 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
210 break;
211 case PRIO_USER:
212 user = (struct user_struct *) cred->user;
213 if (!who)
214 who = cred->uid;
215 else if ((who != cred->uid) &&
216 !(user = find_user(who)))
217 goto out_unlock; /* No processes for this user */
218
219 do_each_thread(g, p) {
220 if (__task_cred(p)->uid == who)
221 error = set_one_prio(p, niceval, error);
222 } while_each_thread(g, p);
223 if (who != cred->uid)
224 free_uid(user); /* For find_user() */
225 break;
226 }
227 out_unlock:
228 read_unlock(&tasklist_lock);
229 rcu_read_unlock();
230 out:
231 return error;
232 }
233
234 /*
235 * Ugh. To avoid negative return values, "getpriority()" will
236 * not return the normal nice-value, but a negated value that
237 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
238 * to stay compatible.
239 */
240 SYSCALL_DEFINE2(getpriority, int, which, int, who)
241 {
242 struct task_struct *g, *p;
243 struct user_struct *user;
244 const struct cred *cred = current_cred();
245 long niceval, retval = -ESRCH;
246 struct pid *pgrp;
247
248 if (which > PRIO_USER || which < PRIO_PROCESS)
249 return -EINVAL;
250
251 rcu_read_lock();
252 read_lock(&tasklist_lock);
253 switch (which) {
254 case PRIO_PROCESS:
255 if (who)
256 p = find_task_by_vpid(who);
257 else
258 p = current;
259 if (p) {
260 niceval = 20 - task_nice(p);
261 if (niceval > retval)
262 retval = niceval;
263 }
264 break;
265 case PRIO_PGRP:
266 if (who)
267 pgrp = find_vpid(who);
268 else
269 pgrp = task_pgrp(current);
270 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
271 niceval = 20 - task_nice(p);
272 if (niceval > retval)
273 retval = niceval;
274 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
275 break;
276 case PRIO_USER:
277 user = (struct user_struct *) cred->user;
278 if (!who)
279 who = cred->uid;
280 else if ((who != cred->uid) &&
281 !(user = find_user(who)))
282 goto out_unlock; /* No processes for this user */
283
284 do_each_thread(g, p) {
285 if (__task_cred(p)->uid == who) {
286 niceval = 20 - task_nice(p);
287 if (niceval > retval)
288 retval = niceval;
289 }
290 } while_each_thread(g, p);
291 if (who != cred->uid)
292 free_uid(user); /* for find_user() */
293 break;
294 }
295 out_unlock:
296 read_unlock(&tasklist_lock);
297 rcu_read_unlock();
298
299 return retval;
300 }
301
302 /**
303 * emergency_restart - reboot the system
304 *
305 * Without shutting down any hardware or taking any locks
306 * reboot the system. This is called when we know we are in
307 * trouble so this is our best effort to reboot. This is
308 * safe to call in interrupt context.
309 */
310 void emergency_restart(void)
311 {
312 kmsg_dump(KMSG_DUMP_EMERG);
313 machine_emergency_restart();
314 }
315 EXPORT_SYMBOL_GPL(emergency_restart);
316
317 void kernel_restart_prepare(char *cmd)
318 {
319 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
320 system_state = SYSTEM_RESTART;
321 usermodehelper_disable();
322 device_shutdown();
323 syscore_shutdown();
324 }
325
326 /**
327 * register_reboot_notifier - Register function to be called at reboot time
328 * @nb: Info about notifier function to be called
329 *
330 * Registers a function with the list of functions
331 * to be called at reboot time.
332 *
333 * Currently always returns zero, as blocking_notifier_chain_register()
334 * always returns zero.
335 */
336 int register_reboot_notifier(struct notifier_block *nb)
337 {
338 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
339 }
340 EXPORT_SYMBOL(register_reboot_notifier);
341
342 /**
343 * unregister_reboot_notifier - Unregister previously registered reboot notifier
344 * @nb: Hook to be unregistered
345 *
346 * Unregisters a previously registered reboot
347 * notifier function.
348 *
349 * Returns zero on success, or %-ENOENT on failure.
350 */
351 int unregister_reboot_notifier(struct notifier_block *nb)
352 {
353 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
354 }
355 EXPORT_SYMBOL(unregister_reboot_notifier);
356
357 /**
358 * kernel_restart - reboot the system
359 * @cmd: pointer to buffer containing command to execute for restart
360 * or %NULL
361 *
362 * Shutdown everything and perform a clean reboot.
363 * This is not safe to call in interrupt context.
364 */
365 void kernel_restart(char *cmd)
366 {
367 kernel_restart_prepare(cmd);
368 if (!cmd)
369 printk(KERN_EMERG "Restarting system.\n");
370 else
371 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
372 kmsg_dump(KMSG_DUMP_RESTART);
373 machine_restart(cmd);
374 }
375 EXPORT_SYMBOL_GPL(kernel_restart);
376
377 static void kernel_shutdown_prepare(enum system_states state)
378 {
379 blocking_notifier_call_chain(&reboot_notifier_list,
380 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
381 system_state = state;
382 usermodehelper_disable();
383 device_shutdown();
384 }
385 /**
386 * kernel_halt - halt the system
387 *
388 * Shutdown everything and perform a clean system halt.
389 */
390 void kernel_halt(void)
391 {
392 kernel_shutdown_prepare(SYSTEM_HALT);
393 syscore_shutdown();
394 printk(KERN_EMERG "System halted.\n");
395 kmsg_dump(KMSG_DUMP_HALT);
396 machine_halt();
397 }
398
399 EXPORT_SYMBOL_GPL(kernel_halt);
400
401 /**
402 * kernel_power_off - power_off the system
403 *
404 * Shutdown everything and perform a clean system power_off.
405 */
406 void kernel_power_off(void)
407 {
408 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
409 if (pm_power_off_prepare)
410 pm_power_off_prepare();
411 disable_nonboot_cpus();
412 syscore_shutdown();
413 printk(KERN_EMERG "Power down.\n");
414 kmsg_dump(KMSG_DUMP_POWEROFF);
415 machine_power_off();
416 }
417 EXPORT_SYMBOL_GPL(kernel_power_off);
418
419 static DEFINE_MUTEX(reboot_mutex);
420
421 /*
422 * Reboot system call: for obvious reasons only root may call it,
423 * and even root needs to set up some magic numbers in the registers
424 * so that some mistake won't make this reboot the whole machine.
425 * You can also set the meaning of the ctrl-alt-del-key here.
426 *
427 * reboot doesn't sync: do that yourself before calling this.
428 */
429 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
430 void __user *, arg)
431 {
432 char buffer[256];
433 int ret = 0;
434
435 /* We only trust the superuser with rebooting the system. */
436 if (!capable(CAP_SYS_BOOT))
437 return -EPERM;
438
439 /* For safety, we require "magic" arguments. */
440 if (magic1 != LINUX_REBOOT_MAGIC1 ||
441 (magic2 != LINUX_REBOOT_MAGIC2 &&
442 magic2 != LINUX_REBOOT_MAGIC2A &&
443 magic2 != LINUX_REBOOT_MAGIC2B &&
444 magic2 != LINUX_REBOOT_MAGIC2C))
445 return -EINVAL;
446
447 /* Instead of trying to make the power_off code look like
448 * halt when pm_power_off is not set do it the easy way.
449 */
450 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
451 cmd = LINUX_REBOOT_CMD_HALT;
452
453 mutex_lock(&reboot_mutex);
454 switch (cmd) {
455 case LINUX_REBOOT_CMD_RESTART:
456 kernel_restart(NULL);
457 break;
458
459 case LINUX_REBOOT_CMD_CAD_ON:
460 C_A_D = 1;
461 break;
462
463 case LINUX_REBOOT_CMD_CAD_OFF:
464 C_A_D = 0;
465 break;
466
467 case LINUX_REBOOT_CMD_HALT:
468 kernel_halt();
469 do_exit(0);
470 panic("cannot halt");
471
472 case LINUX_REBOOT_CMD_POWER_OFF:
473 kernel_power_off();
474 do_exit(0);
475 break;
476
477 case LINUX_REBOOT_CMD_RESTART2:
478 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
479 ret = -EFAULT;
480 break;
481 }
482 buffer[sizeof(buffer) - 1] = '\0';
483
484 kernel_restart(buffer);
485 break;
486
487 #ifdef CONFIG_KEXEC
488 case LINUX_REBOOT_CMD_KEXEC:
489 ret = kernel_kexec();
490 break;
491 #endif
492
493 #ifdef CONFIG_HIBERNATION
494 case LINUX_REBOOT_CMD_SW_SUSPEND:
495 ret = hibernate();
496 break;
497 #endif
498
499 default:
500 ret = -EINVAL;
501 break;
502 }
503 mutex_unlock(&reboot_mutex);
504 return ret;
505 }
506
507 static void deferred_cad(struct work_struct *dummy)
508 {
509 kernel_restart(NULL);
510 }
511
512 /*
513 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
514 * As it's called within an interrupt, it may NOT sync: the only choice
515 * is whether to reboot at once, or just ignore the ctrl-alt-del.
516 */
517 void ctrl_alt_del(void)
518 {
519 static DECLARE_WORK(cad_work, deferred_cad);
520
521 if (C_A_D)
522 schedule_work(&cad_work);
523 else
524 kill_cad_pid(SIGINT, 1);
525 }
526
527 /*
528 * Unprivileged users may change the real gid to the effective gid
529 * or vice versa. (BSD-style)
530 *
531 * If you set the real gid at all, or set the effective gid to a value not
532 * equal to the real gid, then the saved gid is set to the new effective gid.
533 *
534 * This makes it possible for a setgid program to completely drop its
535 * privileges, which is often a useful assertion to make when you are doing
536 * a security audit over a program.
537 *
538 * The general idea is that a program which uses just setregid() will be
539 * 100% compatible with BSD. A program which uses just setgid() will be
540 * 100% compatible with POSIX with saved IDs.
541 *
542 * SMP: There are not races, the GIDs are checked only by filesystem
543 * operations (as far as semantic preservation is concerned).
544 */
545 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
546 {
547 const struct cred *old;
548 struct cred *new;
549 int retval;
550
551 new = prepare_creds();
552 if (!new)
553 return -ENOMEM;
554 old = current_cred();
555
556 retval = -EPERM;
557 if (rgid != (gid_t) -1) {
558 if (old->gid == rgid ||
559 old->egid == rgid ||
560 nsown_capable(CAP_SETGID))
561 new->gid = rgid;
562 else
563 goto error;
564 }
565 if (egid != (gid_t) -1) {
566 if (old->gid == egid ||
567 old->egid == egid ||
568 old->sgid == egid ||
569 nsown_capable(CAP_SETGID))
570 new->egid = egid;
571 else
572 goto error;
573 }
574
575 if (rgid != (gid_t) -1 ||
576 (egid != (gid_t) -1 && egid != old->gid))
577 new->sgid = new->egid;
578 new->fsgid = new->egid;
579
580 return commit_creds(new);
581
582 error:
583 abort_creds(new);
584 return retval;
585 }
586
587 /*
588 * setgid() is implemented like SysV w/ SAVED_IDS
589 *
590 * SMP: Same implicit races as above.
591 */
592 SYSCALL_DEFINE1(setgid, gid_t, gid)
593 {
594 const struct cred *old;
595 struct cred *new;
596 int retval;
597
598 new = prepare_creds();
599 if (!new)
600 return -ENOMEM;
601 old = current_cred();
602
603 retval = -EPERM;
604 if (nsown_capable(CAP_SETGID))
605 new->gid = new->egid = new->sgid = new->fsgid = gid;
606 else if (gid == old->gid || gid == old->sgid)
607 new->egid = new->fsgid = gid;
608 else
609 goto error;
610
611 return commit_creds(new);
612
613 error:
614 abort_creds(new);
615 return retval;
616 }
617
618 /*
619 * change the user struct in a credentials set to match the new UID
620 */
621 static int set_user(struct cred *new)
622 {
623 struct user_struct *new_user;
624
625 new_user = alloc_uid(current_user_ns(), new->uid);
626 if (!new_user)
627 return -EAGAIN;
628
629 /*
630 * We don't fail in case of NPROC limit excess here because too many
631 * poorly written programs don't check set*uid() return code, assuming
632 * it never fails if called by root. We may still enforce NPROC limit
633 * for programs doing set*uid()+execve() by harmlessly deferring the
634 * failure to the execve() stage.
635 */
636 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
637 new_user != INIT_USER)
638 current->flags |= PF_NPROC_EXCEEDED;
639 else
640 current->flags &= ~PF_NPROC_EXCEEDED;
641
642 free_uid(new->user);
643 new->user = new_user;
644 return 0;
645 }
646
647 /*
648 * Unprivileged users may change the real uid to the effective uid
649 * or vice versa. (BSD-style)
650 *
651 * If you set the real uid at all, or set the effective uid to a value not
652 * equal to the real uid, then the saved uid is set to the new effective uid.
653 *
654 * This makes it possible for a setuid program to completely drop its
655 * privileges, which is often a useful assertion to make when you are doing
656 * a security audit over a program.
657 *
658 * The general idea is that a program which uses just setreuid() will be
659 * 100% compatible with BSD. A program which uses just setuid() will be
660 * 100% compatible with POSIX with saved IDs.
661 */
662 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
663 {
664 const struct cred *old;
665 struct cred *new;
666 int retval;
667
668 new = prepare_creds();
669 if (!new)
670 return -ENOMEM;
671 old = current_cred();
672
673 retval = -EPERM;
674 if (ruid != (uid_t) -1) {
675 new->uid = ruid;
676 if (old->uid != ruid &&
677 old->euid != ruid &&
678 !nsown_capable(CAP_SETUID))
679 goto error;
680 }
681
682 if (euid != (uid_t) -1) {
683 new->euid = euid;
684 if (old->uid != euid &&
685 old->euid != euid &&
686 old->suid != euid &&
687 !nsown_capable(CAP_SETUID))
688 goto error;
689 }
690
691 if (new->uid != old->uid) {
692 retval = set_user(new);
693 if (retval < 0)
694 goto error;
695 }
696 if (ruid != (uid_t) -1 ||
697 (euid != (uid_t) -1 && euid != old->uid))
698 new->suid = new->euid;
699 new->fsuid = new->euid;
700
701 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
702 if (retval < 0)
703 goto error;
704
705 return commit_creds(new);
706
707 error:
708 abort_creds(new);
709 return retval;
710 }
711
712 /*
713 * setuid() is implemented like SysV with SAVED_IDS
714 *
715 * Note that SAVED_ID's is deficient in that a setuid root program
716 * like sendmail, for example, cannot set its uid to be a normal
717 * user and then switch back, because if you're root, setuid() sets
718 * the saved uid too. If you don't like this, blame the bright people
719 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
720 * will allow a root program to temporarily drop privileges and be able to
721 * regain them by swapping the real and effective uid.
722 */
723 SYSCALL_DEFINE1(setuid, uid_t, uid)
724 {
725 const struct cred *old;
726 struct cred *new;
727 int retval;
728
729 new = prepare_creds();
730 if (!new)
731 return -ENOMEM;
732 old = current_cred();
733
734 retval = -EPERM;
735 if (nsown_capable(CAP_SETUID)) {
736 new->suid = new->uid = uid;
737 if (uid != old->uid) {
738 retval = set_user(new);
739 if (retval < 0)
740 goto error;
741 }
742 } else if (uid != old->uid && uid != new->suid) {
743 goto error;
744 }
745
746 new->fsuid = new->euid = uid;
747
748 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
749 if (retval < 0)
750 goto error;
751
752 return commit_creds(new);
753
754 error:
755 abort_creds(new);
756 return retval;
757 }
758
759
760 /*
761 * This function implements a generic ability to update ruid, euid,
762 * and suid. This allows you to implement the 4.4 compatible seteuid().
763 */
764 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
765 {
766 const struct cred *old;
767 struct cred *new;
768 int retval;
769
770 new = prepare_creds();
771 if (!new)
772 return -ENOMEM;
773
774 old = current_cred();
775
776 retval = -EPERM;
777 if (!nsown_capable(CAP_SETUID)) {
778 if (ruid != (uid_t) -1 && ruid != old->uid &&
779 ruid != old->euid && ruid != old->suid)
780 goto error;
781 if (euid != (uid_t) -1 && euid != old->uid &&
782 euid != old->euid && euid != old->suid)
783 goto error;
784 if (suid != (uid_t) -1 && suid != old->uid &&
785 suid != old->euid && suid != old->suid)
786 goto error;
787 }
788
789 if (ruid != (uid_t) -1) {
790 new->uid = ruid;
791 if (ruid != old->uid) {
792 retval = set_user(new);
793 if (retval < 0)
794 goto error;
795 }
796 }
797 if (euid != (uid_t) -1)
798 new->euid = euid;
799 if (suid != (uid_t) -1)
800 new->suid = suid;
801 new->fsuid = new->euid;
802
803 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
804 if (retval < 0)
805 goto error;
806
807 return commit_creds(new);
808
809 error:
810 abort_creds(new);
811 return retval;
812 }
813
814 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
815 {
816 const struct cred *cred = current_cred();
817 int retval;
818
819 if (!(retval = put_user(cred->uid, ruid)) &&
820 !(retval = put_user(cred->euid, euid)))
821 retval = put_user(cred->suid, suid);
822
823 return retval;
824 }
825
826 /*
827 * Same as above, but for rgid, egid, sgid.
828 */
829 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
830 {
831 const struct cred *old;
832 struct cred *new;
833 int retval;
834
835 new = prepare_creds();
836 if (!new)
837 return -ENOMEM;
838 old = current_cred();
839
840 retval = -EPERM;
841 if (!nsown_capable(CAP_SETGID)) {
842 if (rgid != (gid_t) -1 && rgid != old->gid &&
843 rgid != old->egid && rgid != old->sgid)
844 goto error;
845 if (egid != (gid_t) -1 && egid != old->gid &&
846 egid != old->egid && egid != old->sgid)
847 goto error;
848 if (sgid != (gid_t) -1 && sgid != old->gid &&
849 sgid != old->egid && sgid != old->sgid)
850 goto error;
851 }
852
853 if (rgid != (gid_t) -1)
854 new->gid = rgid;
855 if (egid != (gid_t) -1)
856 new->egid = egid;
857 if (sgid != (gid_t) -1)
858 new->sgid = sgid;
859 new->fsgid = new->egid;
860
861 return commit_creds(new);
862
863 error:
864 abort_creds(new);
865 return retval;
866 }
867
868 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
869 {
870 const struct cred *cred = current_cred();
871 int retval;
872
873 if (!(retval = put_user(cred->gid, rgid)) &&
874 !(retval = put_user(cred->egid, egid)))
875 retval = put_user(cred->sgid, sgid);
876
877 return retval;
878 }
879
880
881 /*
882 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
883 * is used for "access()" and for the NFS daemon (letting nfsd stay at
884 * whatever uid it wants to). It normally shadows "euid", except when
885 * explicitly set by setfsuid() or for access..
886 */
887 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
888 {
889 const struct cred *old;
890 struct cred *new;
891 uid_t old_fsuid;
892
893 new = prepare_creds();
894 if (!new)
895 return current_fsuid();
896 old = current_cred();
897 old_fsuid = old->fsuid;
898
899 if (uid == old->uid || uid == old->euid ||
900 uid == old->suid || uid == old->fsuid ||
901 nsown_capable(CAP_SETUID)) {
902 if (uid != old_fsuid) {
903 new->fsuid = uid;
904 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
905 goto change_okay;
906 }
907 }
908
909 abort_creds(new);
910 return old_fsuid;
911
912 change_okay:
913 commit_creds(new);
914 return old_fsuid;
915 }
916
917 /*
918 * Samma på svenska..
919 */
920 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
921 {
922 const struct cred *old;
923 struct cred *new;
924 gid_t old_fsgid;
925
926 new = prepare_creds();
927 if (!new)
928 return current_fsgid();
929 old = current_cred();
930 old_fsgid = old->fsgid;
931
932 if (gid == old->gid || gid == old->egid ||
933 gid == old->sgid || gid == old->fsgid ||
934 nsown_capable(CAP_SETGID)) {
935 if (gid != old_fsgid) {
936 new->fsgid = gid;
937 goto change_okay;
938 }
939 }
940
941 abort_creds(new);
942 return old_fsgid;
943
944 change_okay:
945 commit_creds(new);
946 return old_fsgid;
947 }
948
949 void do_sys_times(struct tms *tms)
950 {
951 cputime_t tgutime, tgstime, cutime, cstime;
952
953 spin_lock_irq(&current->sighand->siglock);
954 thread_group_times(current, &tgutime, &tgstime);
955 cutime = current->signal->cutime;
956 cstime = current->signal->cstime;
957 spin_unlock_irq(&current->sighand->siglock);
958 tms->tms_utime = cputime_to_clock_t(tgutime);
959 tms->tms_stime = cputime_to_clock_t(tgstime);
960 tms->tms_cutime = cputime_to_clock_t(cutime);
961 tms->tms_cstime = cputime_to_clock_t(cstime);
962 }
963
964 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
965 {
966 if (tbuf) {
967 struct tms tmp;
968
969 do_sys_times(&tmp);
970 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
971 return -EFAULT;
972 }
973 force_successful_syscall_return();
974 return (long) jiffies_64_to_clock_t(get_jiffies_64());
975 }
976
977 /*
978 * This needs some heavy checking ...
979 * I just haven't the stomach for it. I also don't fully
980 * understand sessions/pgrp etc. Let somebody who does explain it.
981 *
982 * OK, I think I have the protection semantics right.... this is really
983 * only important on a multi-user system anyway, to make sure one user
984 * can't send a signal to a process owned by another. -TYT, 12/12/91
985 *
986 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
987 * LBT 04.03.94
988 */
989 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
990 {
991 struct task_struct *p;
992 struct task_struct *group_leader = current->group_leader;
993 struct pid *pgrp;
994 int err;
995
996 if (!pid)
997 pid = task_pid_vnr(group_leader);
998 if (!pgid)
999 pgid = pid;
1000 if (pgid < 0)
1001 return -EINVAL;
1002 rcu_read_lock();
1003
1004 /* From this point forward we keep holding onto the tasklist lock
1005 * so that our parent does not change from under us. -DaveM
1006 */
1007 write_lock_irq(&tasklist_lock);
1008
1009 err = -ESRCH;
1010 p = find_task_by_vpid(pid);
1011 if (!p)
1012 goto out;
1013
1014 err = -EINVAL;
1015 if (!thread_group_leader(p))
1016 goto out;
1017
1018 if (same_thread_group(p->real_parent, group_leader)) {
1019 err = -EPERM;
1020 if (task_session(p) != task_session(group_leader))
1021 goto out;
1022 err = -EACCES;
1023 if (p->did_exec)
1024 goto out;
1025 } else {
1026 err = -ESRCH;
1027 if (p != group_leader)
1028 goto out;
1029 }
1030
1031 err = -EPERM;
1032 if (p->signal->leader)
1033 goto out;
1034
1035 pgrp = task_pid(p);
1036 if (pgid != pid) {
1037 struct task_struct *g;
1038
1039 pgrp = find_vpid(pgid);
1040 g = pid_task(pgrp, PIDTYPE_PGID);
1041 if (!g || task_session(g) != task_session(group_leader))
1042 goto out;
1043 }
1044
1045 err = security_task_setpgid(p, pgid);
1046 if (err)
1047 goto out;
1048
1049 if (task_pgrp(p) != pgrp)
1050 change_pid(p, PIDTYPE_PGID, pgrp);
1051
1052 err = 0;
1053 out:
1054 /* All paths lead to here, thus we are safe. -DaveM */
1055 write_unlock_irq(&tasklist_lock);
1056 rcu_read_unlock();
1057 return err;
1058 }
1059
1060 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1061 {
1062 struct task_struct *p;
1063 struct pid *grp;
1064 int retval;
1065
1066 rcu_read_lock();
1067 if (!pid)
1068 grp = task_pgrp(current);
1069 else {
1070 retval = -ESRCH;
1071 p = find_task_by_vpid(pid);
1072 if (!p)
1073 goto out;
1074 grp = task_pgrp(p);
1075 if (!grp)
1076 goto out;
1077
1078 retval = security_task_getpgid(p);
1079 if (retval)
1080 goto out;
1081 }
1082 retval = pid_vnr(grp);
1083 out:
1084 rcu_read_unlock();
1085 return retval;
1086 }
1087
1088 #ifdef __ARCH_WANT_SYS_GETPGRP
1089
1090 SYSCALL_DEFINE0(getpgrp)
1091 {
1092 return sys_getpgid(0);
1093 }
1094
1095 #endif
1096
1097 SYSCALL_DEFINE1(getsid, pid_t, pid)
1098 {
1099 struct task_struct *p;
1100 struct pid *sid;
1101 int retval;
1102
1103 rcu_read_lock();
1104 if (!pid)
1105 sid = task_session(current);
1106 else {
1107 retval = -ESRCH;
1108 p = find_task_by_vpid(pid);
1109 if (!p)
1110 goto out;
1111 sid = task_session(p);
1112 if (!sid)
1113 goto out;
1114
1115 retval = security_task_getsid(p);
1116 if (retval)
1117 goto out;
1118 }
1119 retval = pid_vnr(sid);
1120 out:
1121 rcu_read_unlock();
1122 return retval;
1123 }
1124
1125 SYSCALL_DEFINE0(setsid)
1126 {
1127 struct task_struct *group_leader = current->group_leader;
1128 struct pid *sid = task_pid(group_leader);
1129 pid_t session = pid_vnr(sid);
1130 int err = -EPERM;
1131
1132 write_lock_irq(&tasklist_lock);
1133 /* Fail if I am already a session leader */
1134 if (group_leader->signal->leader)
1135 goto out;
1136
1137 /* Fail if a process group id already exists that equals the
1138 * proposed session id.
1139 */
1140 if (pid_task(sid, PIDTYPE_PGID))
1141 goto out;
1142
1143 group_leader->signal->leader = 1;
1144 __set_special_pids(sid);
1145
1146 proc_clear_tty(group_leader);
1147
1148 err = session;
1149 out:
1150 write_unlock_irq(&tasklist_lock);
1151 if (err > 0) {
1152 proc_sid_connector(group_leader);
1153 sched_autogroup_create_attach(group_leader);
1154 }
1155 return err;
1156 }
1157
1158 DECLARE_RWSEM(uts_sem);
1159
1160 #ifdef COMPAT_UTS_MACHINE
1161 #define override_architecture(name) \
1162 (personality(current->personality) == PER_LINUX32 && \
1163 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1164 sizeof(COMPAT_UTS_MACHINE)))
1165 #else
1166 #define override_architecture(name) 0
1167 #endif
1168
1169 /*
1170 * Work around broken programs that cannot handle "Linux 3.0".
1171 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1172 */
1173 static int override_release(char __user *release, int len)
1174 {
1175 int ret = 0;
1176 char buf[65];
1177
1178 if (current->personality & UNAME26) {
1179 char *rest = UTS_RELEASE;
1180 int ndots = 0;
1181 unsigned v;
1182
1183 while (*rest) {
1184 if (*rest == '.' && ++ndots >= 3)
1185 break;
1186 if (!isdigit(*rest) && *rest != '.')
1187 break;
1188 rest++;
1189 }
1190 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1191 snprintf(buf, len, "2.6.%u%s", v, rest);
1192 ret = copy_to_user(release, buf, len);
1193 }
1194 return ret;
1195 }
1196
1197 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1198 {
1199 int errno = 0;
1200
1201 down_read(&uts_sem);
1202 if (copy_to_user(name, utsname(), sizeof *name))
1203 errno = -EFAULT;
1204 up_read(&uts_sem);
1205
1206 if (!errno && override_release(name->release, sizeof(name->release)))
1207 errno = -EFAULT;
1208 if (!errno && override_architecture(name))
1209 errno = -EFAULT;
1210 return errno;
1211 }
1212
1213 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1214 /*
1215 * Old cruft
1216 */
1217 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1218 {
1219 int error = 0;
1220
1221 if (!name)
1222 return -EFAULT;
1223
1224 down_read(&uts_sem);
1225 if (copy_to_user(name, utsname(), sizeof(*name)))
1226 error = -EFAULT;
1227 up_read(&uts_sem);
1228
1229 if (!error && override_release(name->release, sizeof(name->release)))
1230 error = -EFAULT;
1231 if (!error && override_architecture(name))
1232 error = -EFAULT;
1233 return error;
1234 }
1235
1236 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1237 {
1238 int error;
1239
1240 if (!name)
1241 return -EFAULT;
1242 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1243 return -EFAULT;
1244
1245 down_read(&uts_sem);
1246 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1247 __OLD_UTS_LEN);
1248 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1249 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1250 __OLD_UTS_LEN);
1251 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1252 error |= __copy_to_user(&name->release, &utsname()->release,
1253 __OLD_UTS_LEN);
1254 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1255 error |= __copy_to_user(&name->version, &utsname()->version,
1256 __OLD_UTS_LEN);
1257 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1258 error |= __copy_to_user(&name->machine, &utsname()->machine,
1259 __OLD_UTS_LEN);
1260 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1261 up_read(&uts_sem);
1262
1263 if (!error && override_architecture(name))
1264 error = -EFAULT;
1265 if (!error && override_release(name->release, sizeof(name->release)))
1266 error = -EFAULT;
1267 return error ? -EFAULT : 0;
1268 }
1269 #endif
1270
1271 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1272 {
1273 int errno;
1274 char tmp[__NEW_UTS_LEN];
1275
1276 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1277 return -EPERM;
1278
1279 if (len < 0 || len > __NEW_UTS_LEN)
1280 return -EINVAL;
1281 down_write(&uts_sem);
1282 errno = -EFAULT;
1283 if (!copy_from_user(tmp, name, len)) {
1284 struct new_utsname *u = utsname();
1285
1286 memcpy(u->nodename, tmp, len);
1287 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1288 errno = 0;
1289 }
1290 uts_proc_notify(UTS_PROC_HOSTNAME);
1291 up_write(&uts_sem);
1292 return errno;
1293 }
1294
1295 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1296
1297 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1298 {
1299 int i, errno;
1300 struct new_utsname *u;
1301
1302 if (len < 0)
1303 return -EINVAL;
1304 down_read(&uts_sem);
1305 u = utsname();
1306 i = 1 + strlen(u->nodename);
1307 if (i > len)
1308 i = len;
1309 errno = 0;
1310 if (copy_to_user(name, u->nodename, i))
1311 errno = -EFAULT;
1312 up_read(&uts_sem);
1313 return errno;
1314 }
1315
1316 #endif
1317
1318 /*
1319 * Only setdomainname; getdomainname can be implemented by calling
1320 * uname()
1321 */
1322 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1323 {
1324 int errno;
1325 char tmp[__NEW_UTS_LEN];
1326
1327 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1328 return -EPERM;
1329 if (len < 0 || len > __NEW_UTS_LEN)
1330 return -EINVAL;
1331
1332 down_write(&uts_sem);
1333 errno = -EFAULT;
1334 if (!copy_from_user(tmp, name, len)) {
1335 struct new_utsname *u = utsname();
1336
1337 memcpy(u->domainname, tmp, len);
1338 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1339 errno = 0;
1340 }
1341 uts_proc_notify(UTS_PROC_DOMAINNAME);
1342 up_write(&uts_sem);
1343 return errno;
1344 }
1345
1346 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1347 {
1348 struct rlimit value;
1349 int ret;
1350
1351 ret = do_prlimit(current, resource, NULL, &value);
1352 if (!ret)
1353 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1354
1355 return ret;
1356 }
1357
1358 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1359
1360 /*
1361 * Back compatibility for getrlimit. Needed for some apps.
1362 */
1363
1364 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1365 struct rlimit __user *, rlim)
1366 {
1367 struct rlimit x;
1368 if (resource >= RLIM_NLIMITS)
1369 return -EINVAL;
1370
1371 task_lock(current->group_leader);
1372 x = current->signal->rlim[resource];
1373 task_unlock(current->group_leader);
1374 if (x.rlim_cur > 0x7FFFFFFF)
1375 x.rlim_cur = 0x7FFFFFFF;
1376 if (x.rlim_max > 0x7FFFFFFF)
1377 x.rlim_max = 0x7FFFFFFF;
1378 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1379 }
1380
1381 #endif
1382
1383 static inline bool rlim64_is_infinity(__u64 rlim64)
1384 {
1385 #if BITS_PER_LONG < 64
1386 return rlim64 >= ULONG_MAX;
1387 #else
1388 return rlim64 == RLIM64_INFINITY;
1389 #endif
1390 }
1391
1392 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1393 {
1394 if (rlim->rlim_cur == RLIM_INFINITY)
1395 rlim64->rlim_cur = RLIM64_INFINITY;
1396 else
1397 rlim64->rlim_cur = rlim->rlim_cur;
1398 if (rlim->rlim_max == RLIM_INFINITY)
1399 rlim64->rlim_max = RLIM64_INFINITY;
1400 else
1401 rlim64->rlim_max = rlim->rlim_max;
1402 }
1403
1404 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1405 {
1406 if (rlim64_is_infinity(rlim64->rlim_cur))
1407 rlim->rlim_cur = RLIM_INFINITY;
1408 else
1409 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1410 if (rlim64_is_infinity(rlim64->rlim_max))
1411 rlim->rlim_max = RLIM_INFINITY;
1412 else
1413 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1414 }
1415
1416 /* make sure you are allowed to change @tsk limits before calling this */
1417 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1418 struct rlimit *new_rlim, struct rlimit *old_rlim)
1419 {
1420 struct rlimit *rlim;
1421 int retval = 0;
1422
1423 if (resource >= RLIM_NLIMITS)
1424 return -EINVAL;
1425 if (new_rlim) {
1426 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1427 return -EINVAL;
1428 if (resource == RLIMIT_NOFILE &&
1429 new_rlim->rlim_max > sysctl_nr_open)
1430 return -EPERM;
1431 }
1432
1433 /* protect tsk->signal and tsk->sighand from disappearing */
1434 read_lock(&tasklist_lock);
1435 if (!tsk->sighand) {
1436 retval = -ESRCH;
1437 goto out;
1438 }
1439
1440 rlim = tsk->signal->rlim + resource;
1441 task_lock(tsk->group_leader);
1442 if (new_rlim) {
1443 /* Keep the capable check against init_user_ns until
1444 cgroups can contain all limits */
1445 if (new_rlim->rlim_max > rlim->rlim_max &&
1446 !capable(CAP_SYS_RESOURCE))
1447 retval = -EPERM;
1448 if (!retval)
1449 retval = security_task_setrlimit(tsk->group_leader,
1450 resource, new_rlim);
1451 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1452 /*
1453 * The caller is asking for an immediate RLIMIT_CPU
1454 * expiry. But we use the zero value to mean "it was
1455 * never set". So let's cheat and make it one second
1456 * instead
1457 */
1458 new_rlim->rlim_cur = 1;
1459 }
1460 }
1461 if (!retval) {
1462 if (old_rlim)
1463 *old_rlim = *rlim;
1464 if (new_rlim)
1465 *rlim = *new_rlim;
1466 }
1467 task_unlock(tsk->group_leader);
1468
1469 /*
1470 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1471 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1472 * very long-standing error, and fixing it now risks breakage of
1473 * applications, so we live with it
1474 */
1475 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1476 new_rlim->rlim_cur != RLIM_INFINITY)
1477 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1478 out:
1479 read_unlock(&tasklist_lock);
1480 return retval;
1481 }
1482
1483 /* rcu lock must be held */
1484 static int check_prlimit_permission(struct task_struct *task)
1485 {
1486 const struct cred *cred = current_cred(), *tcred;
1487
1488 if (current == task)
1489 return 0;
1490
1491 tcred = __task_cred(task);
1492 if (cred->user->user_ns == tcred->user->user_ns &&
1493 (cred->uid == tcred->euid &&
1494 cred->uid == tcred->suid &&
1495 cred->uid == tcred->uid &&
1496 cred->gid == tcred->egid &&
1497 cred->gid == tcred->sgid &&
1498 cred->gid == tcred->gid))
1499 return 0;
1500 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1501 return 0;
1502
1503 return -EPERM;
1504 }
1505
1506 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1507 const struct rlimit64 __user *, new_rlim,
1508 struct rlimit64 __user *, old_rlim)
1509 {
1510 struct rlimit64 old64, new64;
1511 struct rlimit old, new;
1512 struct task_struct *tsk;
1513 int ret;
1514
1515 if (new_rlim) {
1516 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1517 return -EFAULT;
1518 rlim64_to_rlim(&new64, &new);
1519 }
1520
1521 rcu_read_lock();
1522 tsk = pid ? find_task_by_vpid(pid) : current;
1523 if (!tsk) {
1524 rcu_read_unlock();
1525 return -ESRCH;
1526 }
1527 ret = check_prlimit_permission(tsk);
1528 if (ret) {
1529 rcu_read_unlock();
1530 return ret;
1531 }
1532 get_task_struct(tsk);
1533 rcu_read_unlock();
1534
1535 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1536 old_rlim ? &old : NULL);
1537
1538 if (!ret && old_rlim) {
1539 rlim_to_rlim64(&old, &old64);
1540 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1541 ret = -EFAULT;
1542 }
1543
1544 put_task_struct(tsk);
1545 return ret;
1546 }
1547
1548 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1549 {
1550 struct rlimit new_rlim;
1551
1552 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1553 return -EFAULT;
1554 return do_prlimit(current, resource, &new_rlim, NULL);
1555 }
1556
1557 /*
1558 * It would make sense to put struct rusage in the task_struct,
1559 * except that would make the task_struct be *really big*. After
1560 * task_struct gets moved into malloc'ed memory, it would
1561 * make sense to do this. It will make moving the rest of the information
1562 * a lot simpler! (Which we're not doing right now because we're not
1563 * measuring them yet).
1564 *
1565 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1566 * races with threads incrementing their own counters. But since word
1567 * reads are atomic, we either get new values or old values and we don't
1568 * care which for the sums. We always take the siglock to protect reading
1569 * the c* fields from p->signal from races with exit.c updating those
1570 * fields when reaping, so a sample either gets all the additions of a
1571 * given child after it's reaped, or none so this sample is before reaping.
1572 *
1573 * Locking:
1574 * We need to take the siglock for CHILDEREN, SELF and BOTH
1575 * for the cases current multithreaded, non-current single threaded
1576 * non-current multithreaded. Thread traversal is now safe with
1577 * the siglock held.
1578 * Strictly speaking, we donot need to take the siglock if we are current and
1579 * single threaded, as no one else can take our signal_struct away, no one
1580 * else can reap the children to update signal->c* counters, and no one else
1581 * can race with the signal-> fields. If we do not take any lock, the
1582 * signal-> fields could be read out of order while another thread was just
1583 * exiting. So we should place a read memory barrier when we avoid the lock.
1584 * On the writer side, write memory barrier is implied in __exit_signal
1585 * as __exit_signal releases the siglock spinlock after updating the signal->
1586 * fields. But we don't do this yet to keep things simple.
1587 *
1588 */
1589
1590 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1591 {
1592 r->ru_nvcsw += t->nvcsw;
1593 r->ru_nivcsw += t->nivcsw;
1594 r->ru_minflt += t->min_flt;
1595 r->ru_majflt += t->maj_flt;
1596 r->ru_inblock += task_io_get_inblock(t);
1597 r->ru_oublock += task_io_get_oublock(t);
1598 }
1599
1600 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1601 {
1602 struct task_struct *t;
1603 unsigned long flags;
1604 cputime_t tgutime, tgstime, utime, stime;
1605 unsigned long maxrss = 0;
1606
1607 memset((char *) r, 0, sizeof *r);
1608 utime = stime = cputime_zero;
1609
1610 if (who == RUSAGE_THREAD) {
1611 task_times(current, &utime, &stime);
1612 accumulate_thread_rusage(p, r);
1613 maxrss = p->signal->maxrss;
1614 goto out;
1615 }
1616
1617 if (!lock_task_sighand(p, &flags))
1618 return;
1619
1620 switch (who) {
1621 case RUSAGE_BOTH:
1622 case RUSAGE_CHILDREN:
1623 utime = p->signal->cutime;
1624 stime = p->signal->cstime;
1625 r->ru_nvcsw = p->signal->cnvcsw;
1626 r->ru_nivcsw = p->signal->cnivcsw;
1627 r->ru_minflt = p->signal->cmin_flt;
1628 r->ru_majflt = p->signal->cmaj_flt;
1629 r->ru_inblock = p->signal->cinblock;
1630 r->ru_oublock = p->signal->coublock;
1631 maxrss = p->signal->cmaxrss;
1632
1633 if (who == RUSAGE_CHILDREN)
1634 break;
1635
1636 case RUSAGE_SELF:
1637 thread_group_times(p, &tgutime, &tgstime);
1638 utime = cputime_add(utime, tgutime);
1639 stime = cputime_add(stime, tgstime);
1640 r->ru_nvcsw += p->signal->nvcsw;
1641 r->ru_nivcsw += p->signal->nivcsw;
1642 r->ru_minflt += p->signal->min_flt;
1643 r->ru_majflt += p->signal->maj_flt;
1644 r->ru_inblock += p->signal->inblock;
1645 r->ru_oublock += p->signal->oublock;
1646 if (maxrss < p->signal->maxrss)
1647 maxrss = p->signal->maxrss;
1648 t = p;
1649 do {
1650 accumulate_thread_rusage(t, r);
1651 t = next_thread(t);
1652 } while (t != p);
1653 break;
1654
1655 default:
1656 BUG();
1657 }
1658 unlock_task_sighand(p, &flags);
1659
1660 out:
1661 cputime_to_timeval(utime, &r->ru_utime);
1662 cputime_to_timeval(stime, &r->ru_stime);
1663
1664 if (who != RUSAGE_CHILDREN) {
1665 struct mm_struct *mm = get_task_mm(p);
1666 if (mm) {
1667 setmax_mm_hiwater_rss(&maxrss, mm);
1668 mmput(mm);
1669 }
1670 }
1671 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1672 }
1673
1674 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1675 {
1676 struct rusage r;
1677 k_getrusage(p, who, &r);
1678 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1679 }
1680
1681 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1682 {
1683 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1684 who != RUSAGE_THREAD)
1685 return -EINVAL;
1686 return getrusage(current, who, ru);
1687 }
1688
1689 SYSCALL_DEFINE1(umask, int, mask)
1690 {
1691 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1692 return mask;
1693 }
1694
1695 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1696 unsigned long, arg4, unsigned long, arg5)
1697 {
1698 struct task_struct *me = current;
1699 unsigned char comm[sizeof(me->comm)];
1700 long error;
1701
1702 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1703 if (error != -ENOSYS)
1704 return error;
1705
1706 error = 0;
1707 switch (option) {
1708 case PR_SET_PDEATHSIG:
1709 if (!valid_signal(arg2)) {
1710 error = -EINVAL;
1711 break;
1712 }
1713 me->pdeath_signal = arg2;
1714 error = 0;
1715 break;
1716 case PR_GET_PDEATHSIG:
1717 error = put_user(me->pdeath_signal, (int __user *)arg2);
1718 break;
1719 case PR_GET_DUMPABLE:
1720 error = get_dumpable(me->mm);
1721 break;
1722 case PR_SET_DUMPABLE:
1723 if (arg2 < 0 || arg2 > 1) {
1724 error = -EINVAL;
1725 break;
1726 }
1727 set_dumpable(me->mm, arg2);
1728 error = 0;
1729 break;
1730
1731 case PR_SET_UNALIGN:
1732 error = SET_UNALIGN_CTL(me, arg2);
1733 break;
1734 case PR_GET_UNALIGN:
1735 error = GET_UNALIGN_CTL(me, arg2);
1736 break;
1737 case PR_SET_FPEMU:
1738 error = SET_FPEMU_CTL(me, arg2);
1739 break;
1740 case PR_GET_FPEMU:
1741 error = GET_FPEMU_CTL(me, arg2);
1742 break;
1743 case PR_SET_FPEXC:
1744 error = SET_FPEXC_CTL(me, arg2);
1745 break;
1746 case PR_GET_FPEXC:
1747 error = GET_FPEXC_CTL(me, arg2);
1748 break;
1749 case PR_GET_TIMING:
1750 error = PR_TIMING_STATISTICAL;
1751 break;
1752 case PR_SET_TIMING:
1753 if (arg2 != PR_TIMING_STATISTICAL)
1754 error = -EINVAL;
1755 else
1756 error = 0;
1757 break;
1758
1759 case PR_SET_NAME:
1760 comm[sizeof(me->comm)-1] = 0;
1761 if (strncpy_from_user(comm, (char __user *)arg2,
1762 sizeof(me->comm) - 1) < 0)
1763 return -EFAULT;
1764 set_task_comm(me, comm);
1765 proc_comm_connector(me);
1766 return 0;
1767 case PR_GET_NAME:
1768 get_task_comm(comm, me);
1769 if (copy_to_user((char __user *)arg2, comm,
1770 sizeof(comm)))
1771 return -EFAULT;
1772 return 0;
1773 case PR_GET_ENDIAN:
1774 error = GET_ENDIAN(me, arg2);
1775 break;
1776 case PR_SET_ENDIAN:
1777 error = SET_ENDIAN(me, arg2);
1778 break;
1779
1780 case PR_GET_SECCOMP:
1781 error = prctl_get_seccomp();
1782 break;
1783 case PR_SET_SECCOMP:
1784 error = prctl_set_seccomp(arg2);
1785 break;
1786 case PR_GET_TSC:
1787 error = GET_TSC_CTL(arg2);
1788 break;
1789 case PR_SET_TSC:
1790 error = SET_TSC_CTL(arg2);
1791 break;
1792 case PR_TASK_PERF_EVENTS_DISABLE:
1793 error = perf_event_task_disable();
1794 break;
1795 case PR_TASK_PERF_EVENTS_ENABLE:
1796 error = perf_event_task_enable();
1797 break;
1798 case PR_GET_TIMERSLACK:
1799 error = current->timer_slack_ns;
1800 break;
1801 case PR_SET_TIMERSLACK:
1802 if (arg2 <= 0)
1803 current->timer_slack_ns =
1804 current->default_timer_slack_ns;
1805 else
1806 current->timer_slack_ns = arg2;
1807 error = 0;
1808 break;
1809 case PR_MCE_KILL:
1810 if (arg4 | arg5)
1811 return -EINVAL;
1812 switch (arg2) {
1813 case PR_MCE_KILL_CLEAR:
1814 if (arg3 != 0)
1815 return -EINVAL;
1816 current->flags &= ~PF_MCE_PROCESS;
1817 break;
1818 case PR_MCE_KILL_SET:
1819 current->flags |= PF_MCE_PROCESS;
1820 if (arg3 == PR_MCE_KILL_EARLY)
1821 current->flags |= PF_MCE_EARLY;
1822 else if (arg3 == PR_MCE_KILL_LATE)
1823 current->flags &= ~PF_MCE_EARLY;
1824 else if (arg3 == PR_MCE_KILL_DEFAULT)
1825 current->flags &=
1826 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1827 else
1828 return -EINVAL;
1829 break;
1830 default:
1831 return -EINVAL;
1832 }
1833 error = 0;
1834 break;
1835 case PR_MCE_KILL_GET:
1836 if (arg2 | arg3 | arg4 | arg5)
1837 return -EINVAL;
1838 if (current->flags & PF_MCE_PROCESS)
1839 error = (current->flags & PF_MCE_EARLY) ?
1840 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1841 else
1842 error = PR_MCE_KILL_DEFAULT;
1843 break;
1844 default:
1845 error = -EINVAL;
1846 break;
1847 }
1848 return error;
1849 }
1850
1851 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1852 struct getcpu_cache __user *, unused)
1853 {
1854 int err = 0;
1855 int cpu = raw_smp_processor_id();
1856 if (cpup)
1857 err |= put_user(cpu, cpup);
1858 if (nodep)
1859 err |= put_user(cpu_to_node(cpu), nodep);
1860 return err ? -EFAULT : 0;
1861 }
1862
1863 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1864
1865 static void argv_cleanup(struct subprocess_info *info)
1866 {
1867 argv_free(info->argv);
1868 }
1869
1870 /**
1871 * orderly_poweroff - Trigger an orderly system poweroff
1872 * @force: force poweroff if command execution fails
1873 *
1874 * This may be called from any context to trigger a system shutdown.
1875 * If the orderly shutdown fails, it will force an immediate shutdown.
1876 */
1877 int orderly_poweroff(bool force)
1878 {
1879 int argc;
1880 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1881 static char *envp[] = {
1882 "HOME=/",
1883 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1884 NULL
1885 };
1886 int ret = -ENOMEM;
1887 struct subprocess_info *info;
1888
1889 if (argv == NULL) {
1890 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1891 __func__, poweroff_cmd);
1892 goto out;
1893 }
1894
1895 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1896 if (info == NULL) {
1897 argv_free(argv);
1898 goto out;
1899 }
1900
1901 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1902
1903 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1904
1905 out:
1906 if (ret && force) {
1907 printk(KERN_WARNING "Failed to start orderly shutdown: "
1908 "forcing the issue\n");
1909
1910 /* I guess this should try to kick off some daemon to
1911 sync and poweroff asap. Or not even bother syncing
1912 if we're doing an emergency shutdown? */
1913 emergency_sync();
1914 kernel_power_off();
1915 }
1916
1917 return ret;
1918 }
1919 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linus' kernel tree