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#include <linux/syscore_ops.h>
41
42#include <linux/compat.h>
43#include <linux/syscalls.h>
44#include <linux/kprobes.h>
45#include <linux/user_namespace.h>
46
47#include <linux/kmsg_dump.h>
48
49#include <asm/uaccess.h>
50#include <asm/io.h>
51#include <asm/unistd.h>
52
53#ifndef SET_UNALIGN_CTL
54# define SET_UNALIGN_CTL(a,b) (-EINVAL)
55#endif
56#ifndef GET_UNALIGN_CTL
57# define GET_UNALIGN_CTL(a,b) (-EINVAL)
58#endif
59#ifndef SET_FPEMU_CTL
60# define SET_FPEMU_CTL(a,b) (-EINVAL)
61#endif
62#ifndef GET_FPEMU_CTL
63# define GET_FPEMU_CTL(a,b) (-EINVAL)
64#endif
65#ifndef SET_FPEXC_CTL
66# define SET_FPEXC_CTL(a,b) (-EINVAL)
67#endif
68#ifndef GET_FPEXC_CTL
69# define GET_FPEXC_CTL(a,b) (-EINVAL)
70#endif
71#ifndef GET_ENDIAN
72# define GET_ENDIAN(a,b) (-EINVAL)
73#endif
74#ifndef SET_ENDIAN
75# define SET_ENDIAN(a,b) (-EINVAL)
76#endif
77#ifndef GET_TSC_CTL
78# define GET_TSC_CTL(a) (-EINVAL)
79#endif
80#ifndef SET_TSC_CTL
81# define SET_TSC_CTL(a) (-EINVAL)
82#endif
83
84/*
85 * this is where the system-wide overflow UID and GID are defined, for
86 * architectures that now have 32-bit UID/GID but didn't in the past
87 */
88
89int overflowuid = DEFAULT_OVERFLOWUID;
90int overflowgid = DEFAULT_OVERFLOWGID;
91
92#ifdef CONFIG_UID16
93EXPORT_SYMBOL(overflowuid);
94EXPORT_SYMBOL(overflowgid);
95#endif
96
97/*
98 * the same as above, but for filesystems which can only store a 16-bit
99 * UID and GID. as such, this is needed on all architectures
100 */
101
102int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
103int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
104
105EXPORT_SYMBOL(fs_overflowuid);
106EXPORT_SYMBOL(fs_overflowgid);
107
108/*
109 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
110 */
111
112int C_A_D = 1;
113struct pid *cad_pid;
114EXPORT_SYMBOL(cad_pid);
115
116/*
117 * If set, this is used for preparing the system to power off.
118 */
119
120void (*pm_power_off_prepare)(void);
121
122/*
123 * Returns true if current's euid is same as p's uid or euid,
124 * or has CAP_SYS_NICE to p's user_ns.
125 *
126 * Called with rcu_read_lock, creds are safe
127 */
128static bool set_one_prio_perm(struct task_struct *p)
129{
130    const struct cred *cred = current_cred(), *pcred = __task_cred(p);
131
132    if (pcred->user->user_ns == cred->user->user_ns &&
133        (pcred->uid == cred->euid ||
134         pcred->euid == cred->euid))
135        return true;
136    if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
137        return true;
138    return false;
139}
140
141/*
142 * set the priority of a task
143 * - the caller must hold the RCU read lock
144 */
145static int set_one_prio(struct task_struct *p, int niceval, int error)
146{
147    int no_nice;
148
149    if (!set_one_prio_perm(p)) {
150        error = -EPERM;
151        goto out;
152    }
153    if (niceval < task_nice(p) && !can_nice(p, niceval)) {
154        error = -EACCES;
155        goto out;
156    }
157    no_nice = security_task_setnice(p, niceval);
158    if (no_nice) {
159        error = no_nice;
160        goto out;
161    }
162    if (error == -ESRCH)
163        error = 0;
164    set_user_nice(p, niceval);
165out:
166    return error;
167}
168
169SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
170{
171    struct task_struct *g, *p;
172    struct user_struct *user;
173    const struct cred *cred = current_cred();
174    int error = -EINVAL;
175    struct pid *pgrp;
176
177    if (which > PRIO_USER || which < PRIO_PROCESS)
178        goto out;
179
180    /* normalize: avoid signed division (rounding problems) */
181    error = -ESRCH;
182    if (niceval < -20)
183        niceval = -20;
184    if (niceval > 19)
185        niceval = 19;
186
187    rcu_read_lock();
188    read_lock(&tasklist_lock);
189    switch (which) {
190        case PRIO_PROCESS:
191            if (who)
192                p = find_task_by_vpid(who);
193            else
194                p = current;
195            if (p)
196                error = set_one_prio(p, niceval, error);
197            break;
198        case PRIO_PGRP:
199            if (who)
200                pgrp = find_vpid(who);
201            else
202                pgrp = task_pgrp(current);
203            do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
204                error = set_one_prio(p, niceval, error);
205            } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
206            break;
207        case PRIO_USER:
208            user = (struct user_struct *) cred->user;
209            if (!who)
210                who = cred->uid;
211            else if ((who != cred->uid) &&
212                 !(user = find_user(who)))
213                goto out_unlock; /* No processes for this user */
214
215            do_each_thread(g, p) {
216                if (__task_cred(p)->uid == who)
217                    error = set_one_prio(p, niceval, error);
218            } while_each_thread(g, p);
219            if (who != cred->uid)
220                free_uid(user); /* For find_user() */
221            break;
222    }
223out_unlock:
224    read_unlock(&tasklist_lock);
225    rcu_read_unlock();
226out:
227    return error;
228}
229
230/*
231 * Ugh. To avoid negative return values, "getpriority()" will
232 * not return the normal nice-value, but a negated value that
233 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
234 * to stay compatible.
235 */
236SYSCALL_DEFINE2(getpriority, int, which, int, who)
237{
238    struct task_struct *g, *p;
239    struct user_struct *user;
240    const struct cred *cred = current_cred();
241    long niceval, retval = -ESRCH;
242    struct pid *pgrp;
243
244    if (which > PRIO_USER || which < PRIO_PROCESS)
245        return -EINVAL;
246
247    rcu_read_lock();
248    read_lock(&tasklist_lock);
249    switch (which) {
250        case PRIO_PROCESS:
251            if (who)
252                p = find_task_by_vpid(who);
253            else
254                p = current;
255            if (p) {
256                niceval = 20 - task_nice(p);
257                if (niceval > retval)
258                    retval = niceval;
259            }
260            break;
261        case PRIO_PGRP:
262            if (who)
263                pgrp = find_vpid(who);
264            else
265                pgrp = task_pgrp(current);
266            do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
267                niceval = 20 - task_nice(p);
268                if (niceval > retval)
269                    retval = niceval;
270            } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
271            break;
272        case PRIO_USER:
273            user = (struct user_struct *) cred->user;
274            if (!who)
275                who = cred->uid;
276            else if ((who != cred->uid) &&
277                 !(user = find_user(who)))
278                goto out_unlock; /* No processes for this user */
279
280            do_each_thread(g, p) {
281                if (__task_cred(p)->uid == who) {
282                    niceval = 20 - task_nice(p);
283                    if (niceval > retval)
284                        retval = niceval;
285                }
286            } while_each_thread(g, p);
287            if (who != cred->uid)
288                free_uid(user); /* for find_user() */
289            break;
290    }
291out_unlock:
292    read_unlock(&tasklist_lock);
293    rcu_read_unlock();
294
295    return retval;
296}
297
298/**
299 * emergency_restart - reboot the system
300 *
301 * Without shutting down any hardware or taking any locks
302 * reboot the system. This is called when we know we are in
303 * trouble so this is our best effort to reboot. This is
304 * safe to call in interrupt context.
305 */
306void emergency_restart(void)
307{
308    kmsg_dump(KMSG_DUMP_EMERG);
309    machine_emergency_restart();
310}
311EXPORT_SYMBOL_GPL(emergency_restart);
312
313void kernel_restart_prepare(char *cmd)
314{
315    blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
316    system_state = SYSTEM_RESTART;
317    usermodehelper_disable();
318    device_shutdown();
319    syscore_shutdown();
320}
321
322/**
323 * kernel_restart - reboot the system
324 * @cmd: pointer to buffer containing command to execute for restart
325 * or %NULL
326 *
327 * Shutdown everything and perform a clean reboot.
328 * This is not safe to call in interrupt context.
329 */
330void kernel_restart(char *cmd)
331{
332    kernel_restart_prepare(cmd);
333    if (!cmd)
334        printk(KERN_EMERG "Restarting system.\n");
335    else
336        printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
337    kmsg_dump(KMSG_DUMP_RESTART);
338    machine_restart(cmd);
339}
340EXPORT_SYMBOL_GPL(kernel_restart);
341
342static void kernel_shutdown_prepare(enum system_states state)
343{
344    blocking_notifier_call_chain(&reboot_notifier_list,
345        (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
346    system_state = state;
347    usermodehelper_disable();
348    device_shutdown();
349}
350/**
351 * kernel_halt - halt the system
352 *
353 * Shutdown everything and perform a clean system halt.
354 */
355void kernel_halt(void)
356{
357    kernel_shutdown_prepare(SYSTEM_HALT);
358    syscore_shutdown();
359    printk(KERN_EMERG "System halted.\n");
360    kmsg_dump(KMSG_DUMP_HALT);
361    machine_halt();
362}
363
364EXPORT_SYMBOL_GPL(kernel_halt);
365
366/**
367 * kernel_power_off - power_off the system
368 *
369 * Shutdown everything and perform a clean system power_off.
370 */
371void kernel_power_off(void)
372{
373    kernel_shutdown_prepare(SYSTEM_POWER_OFF);
374    if (pm_power_off_prepare)
375        pm_power_off_prepare();
376    disable_nonboot_cpus();
377    syscore_shutdown();
378    printk(KERN_EMERG "Power down.\n");
379    kmsg_dump(KMSG_DUMP_POWEROFF);
380    machine_power_off();
381}
382EXPORT_SYMBOL_GPL(kernel_power_off);
383
384static DEFINE_MUTEX(reboot_mutex);
385
386/*
387 * Reboot system call: for obvious reasons only root may call it,
388 * and even root needs to set up some magic numbers in the registers
389 * so that some mistake won't make this reboot the whole machine.
390 * You can also set the meaning of the ctrl-alt-del-key here.
391 *
392 * reboot doesn't sync: do that yourself before calling this.
393 */
394SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
395        void __user *, arg)
396{
397    char buffer[256];
398    int ret = 0;
399
400    /* We only trust the superuser with rebooting the system. */
401    if (!capable(CAP_SYS_BOOT))
402        return -EPERM;
403
404    /* For safety, we require "magic" arguments. */
405    if (magic1 != LINUX_REBOOT_MAGIC1 ||
406        (magic2 != LINUX_REBOOT_MAGIC2 &&
407                    magic2 != LINUX_REBOOT_MAGIC2A &&
408            magic2 != LINUX_REBOOT_MAGIC2B &&
409                    magic2 != LINUX_REBOOT_MAGIC2C))
410        return -EINVAL;
411
412    /* Instead of trying to make the power_off code look like
413     * halt when pm_power_off is not set do it the easy way.
414     */
415    if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
416        cmd = LINUX_REBOOT_CMD_HALT;
417
418    mutex_lock(&reboot_mutex);
419    switch (cmd) {
420    case LINUX_REBOOT_CMD_RESTART:
421        kernel_restart(NULL);
422        break;
423
424    case LINUX_REBOOT_CMD_CAD_ON:
425        C_A_D = 1;
426        break;
427
428    case LINUX_REBOOT_CMD_CAD_OFF:
429        C_A_D = 0;
430        break;
431
432    case LINUX_REBOOT_CMD_HALT:
433        kernel_halt();
434        do_exit(0);
435        panic("cannot halt");
436
437    case LINUX_REBOOT_CMD_POWER_OFF:
438        kernel_power_off();
439        do_exit(0);
440        break;
441
442    case LINUX_REBOOT_CMD_RESTART2:
443        if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
444            ret = -EFAULT;
445            break;
446        }
447        buffer[sizeof(buffer) - 1] = '\0';
448
449        kernel_restart(buffer);
450        break;
451
452#ifdef CONFIG_KEXEC
453    case LINUX_REBOOT_CMD_KEXEC:
454        ret = kernel_kexec();
455        break;
456#endif
457
458#ifdef CONFIG_HIBERNATION
459    case LINUX_REBOOT_CMD_SW_SUSPEND:
460        ret = hibernate();
461        break;
462#endif
463
464    default:
465        ret = -EINVAL;
466        break;
467    }
468    mutex_unlock(&reboot_mutex);
469    return ret;
470}
471
472static void deferred_cad(struct work_struct *dummy)
473{
474    kernel_restart(NULL);
475}
476
477/*
478 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
479 * As it's called within an interrupt, it may NOT sync: the only choice
480 * is whether to reboot at once, or just ignore the ctrl-alt-del.
481 */
482void ctrl_alt_del(void)
483{
484    static DECLARE_WORK(cad_work, deferred_cad);
485
486    if (C_A_D)
487        schedule_work(&cad_work);
488    else
489        kill_cad_pid(SIGINT, 1);
490}
491    
492/*
493 * Unprivileged users may change the real gid to the effective gid
494 * or vice versa. (BSD-style)
495 *
496 * If you set the real gid at all, or set the effective gid to a value not
497 * equal to the real gid, then the saved gid is set to the new effective gid.
498 *
499 * This makes it possible for a setgid program to completely drop its
500 * privileges, which is often a useful assertion to make when you are doing
501 * a security audit over a program.
502 *
503 * The general idea is that a program which uses just setregid() will be
504 * 100% compatible with BSD. A program which uses just setgid() will be
505 * 100% compatible with POSIX with saved IDs.
506 *
507 * SMP: There are not races, the GIDs are checked only by filesystem
508 * operations (as far as semantic preservation is concerned).
509 */
510SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
511{
512    const struct cred *old;
513    struct cred *new;
514    int retval;
515
516    new = prepare_creds();
517    if (!new)
518        return -ENOMEM;
519    old = current_cred();
520
521    retval = -EPERM;
522    if (rgid != (gid_t) -1) {
523        if (old->gid == rgid ||
524            old->egid == rgid ||
525            nsown_capable(CAP_SETGID))
526            new->gid = rgid;
527        else
528            goto error;
529    }
530    if (egid != (gid_t) -1) {
531        if (old->gid == egid ||
532            old->egid == egid ||
533            old->sgid == egid ||
534            nsown_capable(CAP_SETGID))
535            new->egid = egid;
536        else
537            goto error;
538    }
539
540    if (rgid != (gid_t) -1 ||
541        (egid != (gid_t) -1 && egid != old->gid))
542        new->sgid = new->egid;
543    new->fsgid = new->egid;
544
545    return commit_creds(new);
546
547error:
548    abort_creds(new);
549    return retval;
550}
551
552/*
553 * setgid() is implemented like SysV w/ SAVED_IDS
554 *
555 * SMP: Same implicit races as above.
556 */
557SYSCALL_DEFINE1(setgid, gid_t, gid)
558{
559    const struct cred *old;
560    struct cred *new;
561    int retval;
562
563    new = prepare_creds();
564    if (!new)
565        return -ENOMEM;
566    old = current_cred();
567
568    retval = -EPERM;
569    if (nsown_capable(CAP_SETGID))
570        new->gid = new->egid = new->sgid = new->fsgid = gid;
571    else if (gid == old->gid || gid == old->sgid)
572        new->egid = new->fsgid = gid;
573    else
574        goto error;
575
576    return commit_creds(new);
577
578error:
579    abort_creds(new);
580    return retval;
581}
582
583/*
584 * change the user struct in a credentials set to match the new UID
585 */
586static int set_user(struct cred *new)
587{
588    struct user_struct *new_user;
589
590    new_user = alloc_uid(current_user_ns(), new->uid);
591    if (!new_user)
592        return -EAGAIN;
593
594    if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
595            new_user != INIT_USER) {
596        free_uid(new_user);
597        return -EAGAIN;
598    }
599
600    free_uid(new->user);
601    new->user = new_user;
602    return 0;
603}
604
605/*
606 * Unprivileged users may change the real uid to the effective uid
607 * or vice versa. (BSD-style)
608 *
609 * If you set the real uid at all, or set the effective uid to a value not
610 * equal to the real uid, then the saved uid is set to the new effective uid.
611 *
612 * This makes it possible for a setuid program to completely drop its
613 * privileges, which is often a useful assertion to make when you are doing
614 * a security audit over a program.
615 *
616 * The general idea is that a program which uses just setreuid() will be
617 * 100% compatible with BSD. A program which uses just setuid() will be
618 * 100% compatible with POSIX with saved IDs.
619 */
620SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
621{
622    const struct cred *old;
623    struct cred *new;
624    int retval;
625
626    new = prepare_creds();
627    if (!new)
628        return -ENOMEM;
629    old = current_cred();
630
631    retval = -EPERM;
632    if (ruid != (uid_t) -1) {
633        new->uid = ruid;
634        if (old->uid != ruid &&
635            old->euid != ruid &&
636            !nsown_capable(CAP_SETUID))
637            goto error;
638    }
639
640    if (euid != (uid_t) -1) {
641        new->euid = euid;
642        if (old->uid != euid &&
643            old->euid != euid &&
644            old->suid != euid &&
645            !nsown_capable(CAP_SETUID))
646            goto error;
647    }
648
649    if (new->uid != old->uid) {
650        retval = set_user(new);
651        if (retval < 0)
652            goto error;
653    }
654    if (ruid != (uid_t) -1 ||
655        (euid != (uid_t) -1 && euid != old->uid))
656        new->suid = new->euid;
657    new->fsuid = new->euid;
658
659    retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
660    if (retval < 0)
661        goto error;
662
663    return commit_creds(new);
664
665error:
666    abort_creds(new);
667    return retval;
668}
669        
670/*
671 * setuid() is implemented like SysV with SAVED_IDS
672 *
673 * Note that SAVED_ID's is deficient in that a setuid root program
674 * like sendmail, for example, cannot set its uid to be a normal
675 * user and then switch back, because if you're root, setuid() sets
676 * the saved uid too. If you don't like this, blame the bright people
677 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
678 * will allow a root program to temporarily drop privileges and be able to
679 * regain them by swapping the real and effective uid.
680 */
681SYSCALL_DEFINE1(setuid, uid_t, uid)
682{
683    const struct cred *old;
684    struct cred *new;
685    int retval;
686
687    new = prepare_creds();
688    if (!new)
689        return -ENOMEM;
690    old = current_cred();
691
692    retval = -EPERM;
693    if (nsown_capable(CAP_SETUID)) {
694        new->suid = new->uid = uid;
695        if (uid != old->uid) {
696            retval = set_user(new);
697            if (retval < 0)
698                goto error;
699        }
700    } else if (uid != old->uid && uid != new->suid) {
701        goto error;
702    }
703
704    new->fsuid = new->euid = uid;
705
706    retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
707    if (retval < 0)
708        goto error;
709
710    return commit_creds(new);
711
712error:
713    abort_creds(new);
714    return retval;
715}
716
717
718/*
719 * This function implements a generic ability to update ruid, euid,
720 * and suid. This allows you to implement the 4.4 compatible seteuid().
721 */
722SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
723{
724    const struct cred *old;
725    struct cred *new;
726    int retval;
727
728    new = prepare_creds();
729    if (!new)
730        return -ENOMEM;
731
732    old = current_cred();
733
734    retval = -EPERM;
735    if (!nsown_capable(CAP_SETUID)) {
736        if (ruid != (uid_t) -1 && ruid != old->uid &&
737            ruid != old->euid && ruid != old->suid)
738            goto error;
739        if (euid != (uid_t) -1 && euid != old->uid &&
740            euid != old->euid && euid != old->suid)
741            goto error;
742        if (suid != (uid_t) -1 && suid != old->uid &&
743            suid != old->euid && suid != old->suid)
744            goto error;
745    }
746
747    if (ruid != (uid_t) -1) {
748        new->uid = ruid;
749        if (ruid != old->uid) {
750            retval = set_user(new);
751            if (retval < 0)
752                goto error;
753        }
754    }
755    if (euid != (uid_t) -1)
756        new->euid = euid;
757    if (suid != (uid_t) -1)
758        new->suid = suid;
759    new->fsuid = new->euid;
760
761    retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
762    if (retval < 0)
763        goto error;
764
765    return commit_creds(new);
766
767error:
768    abort_creds(new);
769    return retval;
770}
771
772SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
773{
774    const struct cred *cred = current_cred();
775    int retval;
776
777    if (!(retval = put_user(cred->uid, ruid)) &&
778        !(retval = put_user(cred->euid, euid)))
779        retval = put_user(cred->suid, suid);
780
781    return retval;
782}
783
784/*
785 * Same as above, but for rgid, egid, sgid.
786 */
787SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
788{
789    const struct cred *old;
790    struct cred *new;
791    int retval;
792
793    new = prepare_creds();
794    if (!new)
795        return -ENOMEM;
796    old = current_cred();
797
798    retval = -EPERM;
799    if (!nsown_capable(CAP_SETGID)) {
800        if (rgid != (gid_t) -1 && rgid != old->gid &&
801            rgid != old->egid && rgid != old->sgid)
802            goto error;
803        if (egid != (gid_t) -1 && egid != old->gid &&
804            egid != old->egid && egid != old->sgid)
805            goto error;
806        if (sgid != (gid_t) -1 && sgid != old->gid &&
807            sgid != old->egid && sgid != old->sgid)
808            goto error;
809    }
810
811    if (rgid != (gid_t) -1)
812        new->gid = rgid;
813    if (egid != (gid_t) -1)
814        new->egid = egid;
815    if (sgid != (gid_t) -1)
816        new->sgid = sgid;
817    new->fsgid = new->egid;
818
819    return commit_creds(new);
820
821error:
822    abort_creds(new);
823    return retval;
824}
825
826SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
827{
828    const struct cred *cred = current_cred();
829    int retval;
830
831    if (!(retval = put_user(cred->gid, rgid)) &&
832        !(retval = put_user(cred->egid, egid)))
833        retval = put_user(cred->sgid, sgid);
834
835    return retval;
836}
837
838
839/*
840 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
841 * is used for "access()" and for the NFS daemon (letting nfsd stay at
842 * whatever uid it wants to). It normally shadows "euid", except when
843 * explicitly set by setfsuid() or for access..
844 */
845SYSCALL_DEFINE1(setfsuid, uid_t, uid)
846{
847    const struct cred *old;
848    struct cred *new;
849    uid_t old_fsuid;
850
851    new = prepare_creds();
852    if (!new)
853        return current_fsuid();
854    old = current_cred();
855    old_fsuid = old->fsuid;
856
857    if (uid == old->uid || uid == old->euid ||
858        uid == old->suid || uid == old->fsuid ||
859        nsown_capable(CAP_SETUID)) {
860        if (uid != old_fsuid) {
861            new->fsuid = uid;
862            if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
863                goto change_okay;
864        }
865    }
866
867    abort_creds(new);
868    return old_fsuid;
869
870change_okay:
871    commit_creds(new);
872    return old_fsuid;
873}
874
875/*
876 * Samma på svenska..
877 */
878SYSCALL_DEFINE1(setfsgid, gid_t, gid)
879{
880    const struct cred *old;
881    struct cred *new;
882    gid_t old_fsgid;
883
884    new = prepare_creds();
885    if (!new)
886        return current_fsgid();
887    old = current_cred();
888    old_fsgid = old->fsgid;
889
890    if (gid == old->gid || gid == old->egid ||
891        gid == old->sgid || gid == old->fsgid ||
892        nsown_capable(CAP_SETGID)) {
893        if (gid != old_fsgid) {
894            new->fsgid = gid;
895            goto change_okay;
896        }
897    }
898
899    abort_creds(new);
900    return old_fsgid;
901
902change_okay:
903    commit_creds(new);
904    return old_fsgid;
905}
906
907void do_sys_times(struct tms *tms)
908{
909    cputime_t tgutime, tgstime, cutime, cstime;
910
911    spin_lock_irq(&current->sighand->siglock);
912    thread_group_times(current, &tgutime, &tgstime);
913    cutime = current->signal->cutime;
914    cstime = current->signal->cstime;
915    spin_unlock_irq(&current->sighand->siglock);
916    tms->tms_utime = cputime_to_clock_t(tgutime);
917    tms->tms_stime = cputime_to_clock_t(tgstime);
918    tms->tms_cutime = cputime_to_clock_t(cutime);
919    tms->tms_cstime = cputime_to_clock_t(cstime);
920}
921
922SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
923{
924    if (tbuf) {
925        struct tms tmp;
926
927        do_sys_times(&tmp);
928        if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
929            return -EFAULT;
930    }
931    force_successful_syscall_return();
932    return (long) jiffies_64_to_clock_t(get_jiffies_64());
933}
934
935/*
936 * This needs some heavy checking ...
937 * I just haven't the stomach for it. I also don't fully
938 * understand sessions/pgrp etc. Let somebody who does explain it.
939 *
940 * OK, I think I have the protection semantics right.... this is really
941 * only important on a multi-user system anyway, to make sure one user
942 * can't send a signal to a process owned by another. -TYT, 12/12/91
943 *
944 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
945 * LBT 04.03.94
946 */
947SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
948{
949    struct task_struct *p;
950    struct task_struct *group_leader = current->group_leader;
951    struct pid *pgrp;
952    int err;
953
954    if (!pid)
955        pid = task_pid_vnr(group_leader);
956    if (!pgid)
957        pgid = pid;
958    if (pgid < 0)
959        return -EINVAL;
960    rcu_read_lock();
961
962    /* From this point forward we keep holding onto the tasklist lock
963     * so that our parent does not change from under us. -DaveM
964     */
965    write_lock_irq(&tasklist_lock);
966
967    err = -ESRCH;
968    p = find_task_by_vpid(pid);
969    if (!p)
970        goto out;
971
972    err = -EINVAL;
973    if (!thread_group_leader(p))
974        goto out;
975
976    if (same_thread_group(p->real_parent, group_leader)) {
977        err = -EPERM;
978        if (task_session(p) != task_session(group_leader))
979            goto out;
980        err = -EACCES;
981        if (p->did_exec)
982            goto out;
983    } else {
984        err = -ESRCH;
985        if (p != group_leader)
986            goto out;
987    }
988
989    err = -EPERM;
990    if (p->signal->leader)
991        goto out;
992
993    pgrp = task_pid(p);
994    if (pgid != pid) {
995        struct task_struct *g;
996
997        pgrp = find_vpid(pgid);
998        g = pid_task(pgrp, PIDTYPE_PGID);
999        if (!g || task_session(g) != task_session(group_leader))
1000            goto out;
1001    }
1002
1003    err = security_task_setpgid(p, pgid);
1004    if (err)
1005        goto out;
1006
1007    if (task_pgrp(p) != pgrp)
1008        change_pid(p, PIDTYPE_PGID, pgrp);
1009
1010    err = 0;
1011out:
1012    /* All paths lead to here, thus we are safe. -DaveM */
1013    write_unlock_irq(&tasklist_lock);
1014    rcu_read_unlock();
1015    return err;
1016}
1017
1018SYSCALL_DEFINE1(getpgid, pid_t, pid)
1019{
1020    struct task_struct *p;
1021    struct pid *grp;
1022    int retval;
1023
1024    rcu_read_lock();
1025    if (!pid)
1026        grp = task_pgrp(current);
1027    else {
1028        retval = -ESRCH;
1029        p = find_task_by_vpid(pid);
1030        if (!p)
1031            goto out;
1032        grp = task_pgrp(p);
1033        if (!grp)
1034            goto out;
1035
1036        retval = security_task_getpgid(p);
1037        if (retval)
1038            goto out;
1039    }
1040    retval = pid_vnr(grp);
1041out:
1042    rcu_read_unlock();
1043    return retval;
1044}
1045
1046#ifdef __ARCH_WANT_SYS_GETPGRP
1047
1048SYSCALL_DEFINE0(getpgrp)
1049{
1050    return sys_getpgid(0);
1051}
1052
1053#endif
1054
1055SYSCALL_DEFINE1(getsid, pid_t, pid)
1056{
1057    struct task_struct *p;
1058    struct pid *sid;
1059    int retval;
1060
1061    rcu_read_lock();
1062    if (!pid)
1063        sid = task_session(current);
1064    else {
1065        retval = -ESRCH;
1066        p = find_task_by_vpid(pid);
1067        if (!p)
1068            goto out;
1069        sid = task_session(p);
1070        if (!sid)
1071            goto out;
1072
1073        retval = security_task_getsid(p);
1074        if (retval)
1075            goto out;
1076    }
1077    retval = pid_vnr(sid);
1078out:
1079    rcu_read_unlock();
1080    return retval;
1081}
1082
1083SYSCALL_DEFINE0(setsid)
1084{
1085    struct task_struct *group_leader = current->group_leader;
1086    struct pid *sid = task_pid(group_leader);
1087    pid_t session = pid_vnr(sid);
1088    int err = -EPERM;
1089
1090    write_lock_irq(&tasklist_lock);
1091    /* Fail if I am already a session leader */
1092    if (group_leader->signal->leader)
1093        goto out;
1094
1095    /* Fail if a process group id already exists that equals the
1096     * proposed session id.
1097     */
1098    if (pid_task(sid, PIDTYPE_PGID))
1099        goto out;
1100
1101    group_leader->signal->leader = 1;
1102    __set_special_pids(sid);
1103
1104    proc_clear_tty(group_leader);
1105
1106    err = session;
1107out:
1108    write_unlock_irq(&tasklist_lock);
1109    if (err > 0) {
1110        proc_sid_connector(group_leader);
1111        sched_autogroup_create_attach(group_leader);
1112    }
1113    return err;
1114}
1115
1116DECLARE_RWSEM(uts_sem);
1117
1118#ifdef COMPAT_UTS_MACHINE
1119#define override_architecture(name) \
1120    (personality(current->personality) == PER_LINUX32 && \
1121     copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1122              sizeof(COMPAT_UTS_MACHINE)))
1123#else
1124#define override_architecture(name) 0
1125#endif
1126
1127SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1128{
1129    int errno = 0;
1130
1131    down_read(&uts_sem);
1132    if (copy_to_user(name, utsname(), sizeof *name))
1133        errno = -EFAULT;
1134    up_read(&uts_sem);
1135
1136    if (!errno && override_architecture(name))
1137        errno = -EFAULT;
1138    return errno;
1139}
1140
1141#ifdef __ARCH_WANT_SYS_OLD_UNAME
1142/*
1143 * Old cruft
1144 */
1145SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1146{
1147    int error = 0;
1148
1149    if (!name)
1150        return -EFAULT;
1151
1152    down_read(&uts_sem);
1153    if (copy_to_user(name, utsname(), sizeof(*name)))
1154        error = -EFAULT;
1155    up_read(&uts_sem);
1156
1157    if (!error && override_architecture(name))
1158        error = -EFAULT;
1159    return error;
1160}
1161
1162SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1163{
1164    int error;
1165
1166    if (!name)
1167        return -EFAULT;
1168    if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1169        return -EFAULT;
1170
1171    down_read(&uts_sem);
1172    error = __copy_to_user(&name->sysname, &utsname()->sysname,
1173                   __OLD_UTS_LEN);
1174    error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1175    error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1176                __OLD_UTS_LEN);
1177    error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1178    error |= __copy_to_user(&name->release, &utsname()->release,
1179                __OLD_UTS_LEN);
1180    error |= __put_user(0, name->release + __OLD_UTS_LEN);
1181    error |= __copy_to_user(&name->version, &utsname()->version,
1182                __OLD_UTS_LEN);
1183    error |= __put_user(0, name->version + __OLD_UTS_LEN);
1184    error |= __copy_to_user(&name->machine, &utsname()->machine,
1185                __OLD_UTS_LEN);
1186    error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1187    up_read(&uts_sem);
1188
1189    if (!error && override_architecture(name))
1190        error = -EFAULT;
1191    return error ? -EFAULT : 0;
1192}
1193#endif
1194
1195SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1196{
1197    int errno;
1198    char tmp[__NEW_UTS_LEN];
1199
1200    if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1201        return -EPERM;
1202
1203    if (len < 0 || len > __NEW_UTS_LEN)
1204        return -EINVAL;
1205    down_write(&uts_sem);
1206    errno = -EFAULT;
1207    if (!copy_from_user(tmp, name, len)) {
1208        struct new_utsname *u = utsname();
1209
1210        memcpy(u->nodename, tmp, len);
1211        memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1212        errno = 0;
1213    }
1214    up_write(&uts_sem);
1215    return errno;
1216}
1217
1218#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1219
1220SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1221{
1222    int i, errno;
1223    struct new_utsname *u;
1224
1225    if (len < 0)
1226        return -EINVAL;
1227    down_read(&uts_sem);
1228    u = utsname();
1229    i = 1 + strlen(u->nodename);
1230    if (i > len)
1231        i = len;
1232    errno = 0;
1233    if (copy_to_user(name, u->nodename, i))
1234        errno = -EFAULT;
1235    up_read(&uts_sem);
1236    return errno;
1237}
1238
1239#endif
1240
1241/*
1242 * Only setdomainname; getdomainname can be implemented by calling
1243 * uname()
1244 */
1245SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1246{
1247    int errno;
1248    char tmp[__NEW_UTS_LEN];
1249
1250    if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1251        return -EPERM;
1252    if (len < 0 || len > __NEW_UTS_LEN)
1253        return -EINVAL;
1254
1255    down_write(&uts_sem);
1256    errno = -EFAULT;
1257    if (!copy_from_user(tmp, name, len)) {
1258        struct new_utsname *u = utsname();
1259
1260        memcpy(u->domainname, tmp, len);
1261        memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1262        errno = 0;
1263    }
1264    up_write(&uts_sem);
1265    return errno;
1266}
1267
1268SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1269{
1270    struct rlimit value;
1271    int ret;
1272
1273    ret = do_prlimit(current, resource, NULL, &value);
1274    if (!ret)
1275        ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1276
1277    return ret;
1278}
1279
1280#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1281
1282/*
1283 * Back compatibility for getrlimit. Needed for some apps.
1284 */
1285 
1286SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1287        struct rlimit __user *, rlim)
1288{
1289    struct rlimit x;
1290    if (resource >= RLIM_NLIMITS)
1291        return -EINVAL;
1292
1293    task_lock(current->group_leader);
1294    x = current->signal->rlim[resource];
1295    task_unlock(current->group_leader);
1296    if (x.rlim_cur > 0x7FFFFFFF)
1297        x.rlim_cur = 0x7FFFFFFF;
1298    if (x.rlim_max > 0x7FFFFFFF)
1299        x.rlim_max = 0x7FFFFFFF;
1300    return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1301}
1302
1303#endif
1304
1305static inline bool rlim64_is_infinity(__u64 rlim64)
1306{
1307#if BITS_PER_LONG < 64
1308    return rlim64 >= ULONG_MAX;
1309#else
1310    return rlim64 == RLIM64_INFINITY;
1311#endif
1312}
1313
1314static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1315{
1316    if (rlim->rlim_cur == RLIM_INFINITY)
1317        rlim64->rlim_cur = RLIM64_INFINITY;
1318    else
1319        rlim64->rlim_cur = rlim->rlim_cur;
1320    if (rlim->rlim_max == RLIM_INFINITY)
1321        rlim64->rlim_max = RLIM64_INFINITY;
1322    else
1323        rlim64->rlim_max = rlim->rlim_max;
1324}
1325
1326static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1327{
1328    if (rlim64_is_infinity(rlim64->rlim_cur))
1329        rlim->rlim_cur = RLIM_INFINITY;
1330    else
1331        rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1332    if (rlim64_is_infinity(rlim64->rlim_max))
1333        rlim->rlim_max = RLIM_INFINITY;
1334    else
1335        rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1336}
1337
1338/* make sure you are allowed to change @tsk limits before calling this */
1339int do_prlimit(struct task_struct *tsk, unsigned int resource,
1340        struct rlimit *new_rlim, struct rlimit *old_rlim)
1341{
1342    struct rlimit *rlim;
1343    int retval = 0;
1344
1345    if (resource >= RLIM_NLIMITS)
1346        return -EINVAL;
1347    if (new_rlim) {
1348        if (new_rlim->rlim_cur > new_rlim->rlim_max)
1349            return -EINVAL;
1350        if (resource == RLIMIT_NOFILE &&
1351                new_rlim->rlim_max > sysctl_nr_open)
1352            return -EPERM;
1353    }
1354
1355    /* protect tsk->signal and tsk->sighand from disappearing */
1356    read_lock(&tasklist_lock);
1357    if (!tsk->sighand) {
1358        retval = -ESRCH;
1359        goto out;
1360    }
1361
1362    rlim = tsk->signal->rlim + resource;
1363    task_lock(tsk->group_leader);
1364    if (new_rlim) {
1365        /* Keep the capable check against init_user_ns until
1366           cgroups can contain all limits */
1367        if (new_rlim->rlim_max > rlim->rlim_max &&
1368                !capable(CAP_SYS_RESOURCE))
1369            retval = -EPERM;
1370        if (!retval)
1371            retval = security_task_setrlimit(tsk->group_leader,
1372                    resource, new_rlim);
1373        if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1374            /*
1375             * The caller is asking for an immediate RLIMIT_CPU
1376             * expiry. But we use the zero value to mean "it was
1377             * never set". So let's cheat and make it one second
1378             * instead
1379             */
1380            new_rlim->rlim_cur = 1;
1381        }
1382    }
1383    if (!retval) {
1384        if (old_rlim)
1385            *old_rlim = *rlim;
1386        if (new_rlim)
1387            *rlim = *new_rlim;
1388    }
1389    task_unlock(tsk->group_leader);
1390
1391    /*
1392     * RLIMIT_CPU handling. Note that the kernel fails to return an error
1393     * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1394     * very long-standing error, and fixing it now risks breakage of
1395     * applications, so we live with it
1396     */
1397     if (!retval && new_rlim && resource == RLIMIT_CPU &&
1398             new_rlim->rlim_cur != RLIM_INFINITY)
1399        update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1400out:
1401    read_unlock(&tasklist_lock);
1402    return retval;
1403}
1404
1405/* rcu lock must be held */
1406static int check_prlimit_permission(struct task_struct *task)
1407{
1408    const struct cred *cred = current_cred(), *tcred;
1409
1410    if (current == task)
1411        return 0;
1412
1413    tcred = __task_cred(task);
1414    if (cred->user->user_ns == tcred->user->user_ns &&
1415        (cred->uid == tcred->euid &&
1416         cred->uid == tcred->suid &&
1417         cred->uid == tcred->uid &&
1418         cred->gid == tcred->egid &&
1419         cred->gid == tcred->sgid &&
1420         cred->gid == tcred->gid))
1421        return 0;
1422    if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1423        return 0;
1424
1425    return -EPERM;
1426}
1427
1428SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1429        const struct rlimit64 __user *, new_rlim,
1430        struct rlimit64 __user *, old_rlim)
1431{
1432    struct rlimit64 old64, new64;
1433    struct rlimit old, new;
1434    struct task_struct *tsk;
1435    int ret;
1436
1437    if (new_rlim) {
1438        if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1439            return -EFAULT;
1440        rlim64_to_rlim(&new64, &new);
1441    }
1442
1443    rcu_read_lock();
1444    tsk = pid ? find_task_by_vpid(pid) : current;
1445    if (!tsk) {
1446        rcu_read_unlock();
1447        return -ESRCH;
1448    }
1449    ret = check_prlimit_permission(tsk);
1450    if (ret) {
1451        rcu_read_unlock();
1452        return ret;
1453    }
1454    get_task_struct(tsk);
1455    rcu_read_unlock();
1456
1457    ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1458            old_rlim ? &old : NULL);
1459
1460    if (!ret && old_rlim) {
1461        rlim_to_rlim64(&old, &old64);
1462        if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1463            ret = -EFAULT;
1464    }
1465
1466    put_task_struct(tsk);
1467    return ret;
1468}
1469
1470SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1471{
1472    struct rlimit new_rlim;
1473
1474    if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1475        return -EFAULT;
1476    return do_prlimit(current, resource, &new_rlim, NULL);
1477}
1478
1479/*
1480 * It would make sense to put struct rusage in the task_struct,
1481 * except that would make the task_struct be *really big*. After
1482 * task_struct gets moved into malloc'ed memory, it would
1483 * make sense to do this. It will make moving the rest of the information
1484 * a lot simpler! (Which we're not doing right now because we're not
1485 * measuring them yet).
1486 *
1487 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1488 * races with threads incrementing their own counters. But since word
1489 * reads are atomic, we either get new values or old values and we don't
1490 * care which for the sums. We always take the siglock to protect reading
1491 * the c* fields from p->signal from races with exit.c updating those
1492 * fields when reaping, so a sample either gets all the additions of a
1493 * given child after it's reaped, or none so this sample is before reaping.
1494 *
1495 * Locking:
1496 * We need to take the siglock for CHILDEREN, SELF and BOTH
1497 * for the cases current multithreaded, non-current single threaded
1498 * non-current multithreaded. Thread traversal is now safe with
1499 * the siglock held.
1500 * Strictly speaking, we donot need to take the siglock if we are current and
1501 * single threaded, as no one else can take our signal_struct away, no one
1502 * else can reap the children to update signal->c* counters, and no one else
1503 * can race with the signal-> fields. If we do not take any lock, the
1504 * signal-> fields could be read out of order while another thread was just
1505 * exiting. So we should place a read memory barrier when we avoid the lock.
1506 * On the writer side, write memory barrier is implied in __exit_signal
1507 * as __exit_signal releases the siglock spinlock after updating the signal->
1508 * fields. But we don't do this yet to keep things simple.
1509 *
1510 */
1511
1512static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1513{
1514    r->ru_nvcsw += t->nvcsw;
1515    r->ru_nivcsw += t->nivcsw;
1516    r->ru_minflt += t->min_flt;
1517    r->ru_majflt += t->maj_flt;
1518    r->ru_inblock += task_io_get_inblock(t);
1519    r->ru_oublock += task_io_get_oublock(t);
1520}
1521
1522static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1523{
1524    struct task_struct *t;
1525    unsigned long flags;
1526    cputime_t tgutime, tgstime, utime, stime;
1527    unsigned long maxrss = 0;
1528
1529    memset((char *) r, 0, sizeof *r);
1530    utime = stime = cputime_zero;
1531
1532    if (who == RUSAGE_THREAD) {
1533        task_times(current, &utime, &stime);
1534        accumulate_thread_rusage(p, r);
1535        maxrss = p->signal->maxrss;
1536        goto out;
1537    }
1538
1539    if (!lock_task_sighand(p, &flags))
1540        return;
1541
1542    switch (who) {
1543        case RUSAGE_BOTH:
1544        case RUSAGE_CHILDREN:
1545            utime = p->signal->cutime;
1546            stime = p->signal->cstime;
1547            r->ru_nvcsw = p->signal->cnvcsw;
1548            r->ru_nivcsw = p->signal->cnivcsw;
1549            r->ru_minflt = p->signal->cmin_flt;
1550            r->ru_majflt = p->signal->cmaj_flt;
1551            r->ru_inblock = p->signal->cinblock;
1552            r->ru_oublock = p->signal->coublock;
1553            maxrss = p->signal->cmaxrss;
1554
1555            if (who == RUSAGE_CHILDREN)
1556                break;
1557
1558        case RUSAGE_SELF:
1559            thread_group_times(p, &tgutime, &tgstime);
1560            utime = cputime_add(utime, tgutime);
1561            stime = cputime_add(stime, tgstime);
1562            r->ru_nvcsw += p->signal->nvcsw;
1563            r->ru_nivcsw += p->signal->nivcsw;
1564            r->ru_minflt += p->signal->min_flt;
1565            r->ru_majflt += p->signal->maj_flt;
1566            r->ru_inblock += p->signal->inblock;
1567            r->ru_oublock += p->signal->oublock;
1568            if (maxrss < p->signal->maxrss)
1569                maxrss = p->signal->maxrss;
1570            t = p;
1571            do {
1572                accumulate_thread_rusage(t, r);
1573                t = next_thread(t);
1574            } while (t != p);
1575            break;
1576
1577        default:
1578            BUG();
1579    }
1580    unlock_task_sighand(p, &flags);
1581
1582out:
1583    cputime_to_timeval(utime, &r->ru_utime);
1584    cputime_to_timeval(stime, &r->ru_stime);
1585
1586    if (who != RUSAGE_CHILDREN) {
1587        struct mm_struct *mm = get_task_mm(p);
1588        if (mm) {
1589            setmax_mm_hiwater_rss(&maxrss, mm);
1590            mmput(mm);
1591        }
1592    }
1593    r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1594}
1595
1596int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1597{
1598    struct rusage r;
1599    k_getrusage(p, who, &r);
1600    return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1601}
1602
1603SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1604{
1605    if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1606        who != RUSAGE_THREAD)
1607        return -EINVAL;
1608    return getrusage(current, who, ru);
1609}
1610
1611SYSCALL_DEFINE1(umask, int, mask)
1612{
1613    mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1614    return mask;
1615}
1616
1617SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1618        unsigned long, arg4, unsigned long, arg5)
1619{
1620    struct task_struct *me = current;
1621    unsigned char comm[sizeof(me->comm)];
1622    long error;
1623
1624    error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1625    if (error != -ENOSYS)
1626        return error;
1627
1628    error = 0;
1629    switch (option) {
1630        case PR_SET_PDEATHSIG:
1631            if (!valid_signal(arg2)) {
1632                error = -EINVAL;
1633                break;
1634            }
1635            me->pdeath_signal = arg2;
1636            error = 0;
1637            break;
1638        case PR_GET_PDEATHSIG:
1639            error = put_user(me->pdeath_signal, (int __user *)arg2);
1640            break;
1641        case PR_GET_DUMPABLE:
1642            error = get_dumpable(me->mm);
1643            break;
1644        case PR_SET_DUMPABLE:
1645            if (arg2 < 0 || arg2 > 1) {
1646                error = -EINVAL;
1647                break;
1648            }
1649            set_dumpable(me->mm, arg2);
1650            error = 0;
1651            break;
1652
1653        case PR_SET_UNALIGN:
1654            error = SET_UNALIGN_CTL(me, arg2);
1655            break;
1656        case PR_GET_UNALIGN:
1657            error = GET_UNALIGN_CTL(me, arg2);
1658            break;
1659        case PR_SET_FPEMU:
1660            error = SET_FPEMU_CTL(me, arg2);
1661            break;
1662        case PR_GET_FPEMU:
1663            error = GET_FPEMU_CTL(me, arg2);
1664            break;
1665        case PR_SET_FPEXC:
1666            error = SET_FPEXC_CTL(me, arg2);
1667            break;
1668        case PR_GET_FPEXC:
1669            error = GET_FPEXC_CTL(me, arg2);
1670            break;
1671        case PR_GET_TIMING:
1672            error = PR_TIMING_STATISTICAL;
1673            break;
1674        case PR_SET_TIMING:
1675            if (arg2 != PR_TIMING_STATISTICAL)
1676                error = -EINVAL;
1677            else
1678                error = 0;
1679            break;
1680
1681        case PR_SET_NAME:
1682            comm[sizeof(me->comm)-1] = 0;
1683            if (strncpy_from_user(comm, (char __user *)arg2,
1684                          sizeof(me->comm) - 1) < 0)
1685                return -EFAULT;
1686            set_task_comm(me, comm);
1687            return 0;
1688        case PR_GET_NAME:
1689            get_task_comm(comm, me);
1690            if (copy_to_user((char __user *)arg2, comm,
1691                     sizeof(comm)))
1692                return -EFAULT;
1693            return 0;
1694        case PR_GET_ENDIAN:
1695            error = GET_ENDIAN(me, arg2);
1696            break;
1697        case PR_SET_ENDIAN:
1698            error = SET_ENDIAN(me, arg2);
1699            break;
1700
1701        case PR_GET_SECCOMP:
1702            error = prctl_get_seccomp();
1703            break;
1704        case PR_SET_SECCOMP:
1705            error = prctl_set_seccomp(arg2);
1706            break;
1707        case PR_GET_TSC:
1708            error = GET_TSC_CTL(arg2);
1709            break;
1710        case PR_SET_TSC:
1711            error = SET_TSC_CTL(arg2);
1712            break;
1713        case PR_TASK_PERF_EVENTS_DISABLE:
1714            error = perf_event_task_disable();
1715            break;
1716        case PR_TASK_PERF_EVENTS_ENABLE:
1717            error = perf_event_task_enable();
1718            break;
1719        case PR_GET_TIMERSLACK:
1720            error = current->timer_slack_ns;
1721            break;
1722        case PR_SET_TIMERSLACK:
1723            if (arg2 <= 0)
1724                current->timer_slack_ns =
1725                    current->default_timer_slack_ns;
1726            else
1727                current->timer_slack_ns = arg2;
1728            error = 0;
1729            break;
1730        case PR_MCE_KILL:
1731            if (arg4 | arg5)
1732                return -EINVAL;
1733            switch (arg2) {
1734            case PR_MCE_KILL_CLEAR:
1735                if (arg3 != 0)
1736                    return -EINVAL;
1737                current->flags &= ~PF_MCE_PROCESS;
1738                break;
1739            case PR_MCE_KILL_SET:
1740                current->flags |= PF_MCE_PROCESS;
1741                if (arg3 == PR_MCE_KILL_EARLY)
1742                    current->flags |= PF_MCE_EARLY;
1743                else if (arg3 == PR_MCE_KILL_LATE)
1744                    current->flags &= ~PF_MCE_EARLY;
1745                else if (arg3 == PR_MCE_KILL_DEFAULT)
1746                    current->flags &=
1747                        ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1748                else
1749                    return -EINVAL;
1750                break;
1751            default:
1752                return -EINVAL;
1753            }
1754            error = 0;
1755            break;
1756        case PR_MCE_KILL_GET:
1757            if (arg2 | arg3 | arg4 | arg5)
1758                return -EINVAL;
1759            if (current->flags & PF_MCE_PROCESS)
1760                error = (current->flags & PF_MCE_EARLY) ?
1761                    PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1762            else
1763                error = PR_MCE_KILL_DEFAULT;
1764            break;
1765        default:
1766            error = -EINVAL;
1767            break;
1768    }
1769    return error;
1770}
1771
1772SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1773        struct getcpu_cache __user *, unused)
1774{
1775    int err = 0;
1776    int cpu = raw_smp_processor_id();
1777    if (cpup)
1778        err |= put_user(cpu, cpup);
1779    if (nodep)
1780        err |= put_user(cpu_to_node(cpu), nodep);
1781    return err ? -EFAULT : 0;
1782}
1783
1784char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1785
1786static void argv_cleanup(struct subprocess_info *info)
1787{
1788    argv_free(info->argv);
1789}
1790
1791/**
1792 * orderly_poweroff - Trigger an orderly system poweroff
1793 * @force: force poweroff if command execution fails
1794 *
1795 * This may be called from any context to trigger a system shutdown.
1796 * If the orderly shutdown fails, it will force an immediate shutdown.
1797 */
1798int orderly_poweroff(bool force)
1799{
1800    int argc;
1801    char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1802    static char *envp[] = {
1803        "HOME=/",
1804        "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1805        NULL
1806    };
1807    int ret = -ENOMEM;
1808    struct subprocess_info *info;
1809
1810    if (argv == NULL) {
1811        printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1812               __func__, poweroff_cmd);
1813        goto out;
1814    }
1815
1816    info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1817    if (info == NULL) {
1818        argv_free(argv);
1819        goto out;
1820    }
1821
1822    call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1823
1824    ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1825
1826  out:
1827    if (ret && force) {
1828        printk(KERN_WARNING "Failed to start orderly shutdown: "
1829               "forcing the issue\n");
1830
1831        /* I guess this should try to kick off some daemon to
1832           sync and poweroff asap. Or not even bother syncing
1833           if we're doing an emergency shutdown? */
1834        emergency_sync();
1835        kernel_power_off();
1836    }
1837
1838    return ret;
1839}
1840EXPORT_SYMBOL_GPL(orderly_poweroff);
1841

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