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Root/kernel/sys.c

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

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