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
88int overflowuid = DEFAULT_OVERFLOWUID;
89int overflowgid = DEFAULT_OVERFLOWGID;
90
91#ifdef CONFIG_UID16
92EXPORT_SYMBOL(overflowuid);
93EXPORT_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
101int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
102int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
103
104EXPORT_SYMBOL(fs_overflowuid);
105EXPORT_SYMBOL(fs_overflowgid);
106
107/*
108 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
109 */
110
111int C_A_D = 1;
112struct pid *cad_pid;
113EXPORT_SYMBOL(cad_pid);
114
115/*
116 * If set, this is used for preparing the system to power off.
117 */
118
119void (*pm_power_off_prepare)(void);
120
121/*
122 * set the priority of a task
123 * - the caller must hold the RCU read lock
124 */
125static 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);
147out:
148    return error;
149}
150
151SYSCALL_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    }
205out_unlock:
206    read_unlock(&tasklist_lock);
207    rcu_read_unlock();
208out:
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 */
218SYSCALL_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    }
273out_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 */
288void emergency_restart(void)
289{
290    kmsg_dump(KMSG_DUMP_EMERG);
291    machine_emergency_restart();
292}
293EXPORT_SYMBOL_GPL(emergency_restart);
294
295void 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 */
311void 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}
321EXPORT_SYMBOL_GPL(kernel_restart);
322
323static 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 */
335void 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
344EXPORT_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 */
351void 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}
362EXPORT_SYMBOL_GPL(kernel_power_off);
363
364static 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 */
374SYSCALL_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
452static 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 */
462void 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 */
490SYSCALL_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
527error:
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 */
537SYSCALL_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
558error:
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 */
566static 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 */
600SYSCALL_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
645error:
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 */
661SYSCALL_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
692error:
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 */
702SYSCALL_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
747error:
748    abort_creds(new);
749    return retval;
750}
751
752SYSCALL_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 */
767SYSCALL_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
801error:
802    abort_creds(new);
803    return retval;
804}
805
806SYSCALL_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 */
825SYSCALL_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
850change_okay:
851    commit_creds(new);
852    return old_fsuid;
853}
854
855/*
856 * Samma på svenska..
857 */
858SYSCALL_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
882change_okay:
883    commit_creds(new);
884    return old_fsgid;
885}
886
887void 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
902SYSCALL_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 */
927SYSCALL_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;
991out:
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
998SYSCALL_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);
1021out:
1022    rcu_read_unlock();
1023    return retval;
1024}
1025
1026#ifdef __ARCH_WANT_SYS_GETPGRP
1027
1028SYSCALL_DEFINE0(getpgrp)
1029{
1030    return sys_getpgid(0);
1031}
1032
1033#endif
1034
1035SYSCALL_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);
1058out:
1059    rcu_read_unlock();
1060    return retval;
1061}
1062
1063SYSCALL_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;
1087out:
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
1096DECLARE_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
1107SYSCALL_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 */
1125SYSCALL_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
1142SYSCALL_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
1175SYSCALL_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
1199SYSCALL_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 */
1224SYSCALL_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
1247SYSCALL_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 
1265SYSCALL_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
1284static 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
1293static 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
1305static 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 */
1318int 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);
1377out:
1378    read_unlock(&tasklist_lock);
1379    return retval;
1380}
1381
1382/* rcu lock must be held */
1383static 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
1402SYSCALL_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
1444SYSCALL_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
1486static 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
1496static 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
1556out:
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
1570int 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
1577SYSCALL_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
1585SYSCALL_DEFINE1(umask, int, mask)
1586{
1587    mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1588    return mask;
1589}
1590
1591SYSCALL_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
1746SYSCALL_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
1758char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1759
1760static 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 */
1772int 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}
1814EXPORT_SYMBOL_GPL(orderly_poweroff);
1815

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