projects/linux·blob v3.7-rc8 · refs

2244 lines · 52.2 KiB

1/*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/export.h>
8#include <linux/mm.h>
9#include <linux/utsname.h>
10#include <linux/mman.h>
11#include <linux/reboot.h>
12#include <linux/prctl.h>
13#include <linux/highuid.h>
14#include <linux/fs.h>
15#include <linux/kmod.h>
16#include <linux/perf_event.h>
17#include <linux/resource.h>
18#include <linux/kernel.h>
19#include <linux/kexec.h>
20#include <linux/workqueue.h>
21#include <linux/capability.h>
22#include <linux/device.h>
23#include <linux/key.h>
24#include <linux/times.h>
25#include <linux/posix-timers.h>
26#include <linux/security.h>
27#include <linux/dcookies.h>
28#include <linux/suspend.h>
29#include <linux/tty.h>
30#include <linux/signal.h>
31#include <linux/cn_proc.h>
32#include <linux/getcpu.h>
33#include <linux/task_io_accounting_ops.h>
34#include <linux/seccomp.h>
35#include <linux/cpu.h>
36#include <linux/personality.h>
37#include <linux/ptrace.h>
38#include <linux/fs_struct.h>
39#include <linux/file.h>
40#include <linux/mount.h>
41#include <linux/gfp.h>
42#include <linux/syscore_ops.h>
43#include <linux/version.h>
44#include <linux/ctype.h>
45
46#include <linux/compat.h>
47#include <linux/syscalls.h>
48#include <linux/kprobes.h>
49#include <linux/user_namespace.h>
50
51#include <linux/kmsg_dump.h>
52/* Move somewhere else to avoid recompiling? */
53#include <generated/utsrelease.h>
54
55#include <asm/uaccess.h>
56#include <asm/io.h>
57#include <asm/unistd.h>
58
59#ifndef SET_UNALIGN_CTL
60# define SET_UNALIGN_CTL(a,b) (-EINVAL)
61#endif
62#ifndef GET_UNALIGN_CTL
63# define GET_UNALIGN_CTL(a,b) (-EINVAL)
64#endif
65#ifndef SET_FPEMU_CTL
66# define SET_FPEMU_CTL(a,b) (-EINVAL)
67#endif
68#ifndef GET_FPEMU_CTL
69# define GET_FPEMU_CTL(a,b) (-EINVAL)
70#endif
71#ifndef SET_FPEXC_CTL
72# define SET_FPEXC_CTL(a,b) (-EINVAL)
73#endif
74#ifndef GET_FPEXC_CTL
75# define GET_FPEXC_CTL(a,b) (-EINVAL)
76#endif
77#ifndef GET_ENDIAN
78# define GET_ENDIAN(a,b) (-EINVAL)
79#endif
80#ifndef SET_ENDIAN
81# define SET_ENDIAN(a,b) (-EINVAL)
82#endif
83#ifndef GET_TSC_CTL
84# define GET_TSC_CTL(a) (-EINVAL)
85#endif
86#ifndef SET_TSC_CTL
87# define SET_TSC_CTL(a) (-EINVAL)
88#endif
89
90/*
91 * this is where the system-wide overflow UID and GID are defined, for
92 * architectures that now have 32-bit UID/GID but didn't in the past
93 */
94
95int overflowuid = DEFAULT_OVERFLOWUID;
96int overflowgid = DEFAULT_OVERFLOWGID;
97
98EXPORT_SYMBOL(overflowuid);
99EXPORT_SYMBOL(overflowgid);
100
101/*
102 * the same as above, but for filesystems which can only store a 16-bit
103 * UID and GID. as such, this is needed on all architectures
104 */
105
106int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
107int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
108
109EXPORT_SYMBOL(fs_overflowuid);
110EXPORT_SYMBOL(fs_overflowgid);
111
112/*
113 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
114 */
115
116int C_A_D = 1;
117struct pid *cad_pid;
118EXPORT_SYMBOL(cad_pid);
119
120/*
121 * If set, this is used for preparing the system to power off.
122 */
123
124void (*pm_power_off_prepare)(void);
125
126/*
127 * Returns true if current's euid is same as p's uid or euid,
128 * or has CAP_SYS_NICE to p's user_ns.
129 *
130 * Called with rcu_read_lock, creds are safe
131 */
132static bool set_one_prio_perm(struct task_struct *p)
133{
134 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
135
136 if (uid_eq(pcred->uid, cred->euid) ||
137 uid_eq(pcred->euid, cred->euid))
138 return true;
139 if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
140 return true;
141 return false;
142}
143
144/*
145 * set the priority of a task
146 * - the caller must hold the RCU read lock
147 */
148static int set_one_prio(struct task_struct *p, int niceval, int error)
149{
150 int no_nice;
151
152 if (!set_one_prio_perm(p)) {
153 error = -EPERM;
154 goto out;
155 }
156 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
157 error = -EACCES;
158 goto out;
159 }
160 no_nice = security_task_setnice(p, niceval);
161 if (no_nice) {
162 error = no_nice;
163 goto out;
164 }
165 if (error == -ESRCH)
166 error = 0;
167 set_user_nice(p, niceval);
168out:
169 return error;
170}
171
172SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
173{
174 struct task_struct *g, *p;
175 struct user_struct *user;
176 const struct cred *cred = current_cred();
177 int error = -EINVAL;
178 struct pid *pgrp;
179 kuid_t uid;
180
181 if (which > PRIO_USER || which < PRIO_PROCESS)
182 goto out;
183
184 /* normalize: avoid signed division (rounding problems) */
185 error = -ESRCH;
186 if (niceval < -20)
187 niceval = -20;
188 if (niceval > 19)
189 niceval = 19;
190
191 rcu_read_lock();
192 read_lock(&tasklist_lock);
193 switch (which) {
194 case PRIO_PROCESS:
195 if (who)
196 p = find_task_by_vpid(who);
197 else
198 p = current;
199 if (p)
200 error = set_one_prio(p, niceval, error);
201 break;
202 case PRIO_PGRP:
203 if (who)
204 pgrp = find_vpid(who);
205 else
206 pgrp = task_pgrp(current);
207 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
208 error = set_one_prio(p, niceval, error);
209 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
210 break;
211 case PRIO_USER:
212 uid = make_kuid(cred->user_ns, who);
213 user = cred->user;
214 if (!who)
215 uid = cred->uid;
216 else if (!uid_eq(uid, cred->uid) &&
217 !(user = find_user(uid)))
218 goto out_unlock; /* No processes for this user */
219
220 do_each_thread(g, p) {
221 if (uid_eq(task_uid(p), uid))
222 error = set_one_prio(p, niceval, error);
223 } while_each_thread(g, p);
224 if (!uid_eq(uid, cred->uid))
225 free_uid(user); /* For find_user() */
226 break;
227 }
228out_unlock:
229 read_unlock(&tasklist_lock);
230 rcu_read_unlock();
231out:
232 return error;
233}
234
235/*
236 * Ugh. To avoid negative return values, "getpriority()" will
237 * not return the normal nice-value, but a negated value that
238 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
239 * to stay compatible.
240 */
241SYSCALL_DEFINE2(getpriority, int, which, int, who)
242{
243 struct task_struct *g, *p;
244 struct user_struct *user;
245 const struct cred *cred = current_cred();
246 long niceval, retval = -ESRCH;
247 struct pid *pgrp;
248 kuid_t uid;
249
250 if (which > PRIO_USER || which < PRIO_PROCESS)
251 return -EINVAL;
252
253 rcu_read_lock();
254 read_lock(&tasklist_lock);
255 switch (which) {
256 case PRIO_PROCESS:
257 if (who)
258 p = find_task_by_vpid(who);
259 else
260 p = current;
261 if (p) {
262 niceval = 20 - task_nice(p);
263 if (niceval > retval)
264 retval = niceval;
265 }
266 break;
267 case PRIO_PGRP:
268 if (who)
269 pgrp = find_vpid(who);
270 else
271 pgrp = task_pgrp(current);
272 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
273 niceval = 20 - task_nice(p);
274 if (niceval > retval)
275 retval = niceval;
276 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
277 break;
278 case PRIO_USER:
279 uid = make_kuid(cred->user_ns, who);
280 user = cred->user;
281 if (!who)
282 uid = cred->uid;
283 else if (!uid_eq(uid, cred->uid) &&
284 !(user = find_user(uid)))
285 goto out_unlock; /* No processes for this user */
286
287 do_each_thread(g, p) {
288 if (uid_eq(task_uid(p), uid)) {
289 niceval = 20 - task_nice(p);
290 if (niceval > retval)
291 retval = niceval;
292 }
293 } while_each_thread(g, p);
294 if (!uid_eq(uid, cred->uid))
295 free_uid(user); /* for find_user() */
296 break;
297 }
298out_unlock:
299 read_unlock(&tasklist_lock);
300 rcu_read_unlock();
301
302 return retval;
303}
304
305/**
306 * emergency_restart - reboot the system
307 *
308 * Without shutting down any hardware or taking any locks
309 * reboot the system. This is called when we know we are in
310 * trouble so this is our best effort to reboot. This is
311 * safe to call in interrupt context.
312 */
313void emergency_restart(void)
314{
315 kmsg_dump(KMSG_DUMP_EMERG);
316 machine_emergency_restart();
317}
318EXPORT_SYMBOL_GPL(emergency_restart);
319
320void kernel_restart_prepare(char *cmd)
321{
322 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
323 system_state = SYSTEM_RESTART;
324 usermodehelper_disable();
325 device_shutdown();
326 syscore_shutdown();
327}
328
329/**
330 * register_reboot_notifier - Register function to be called at reboot time
331 * @nb: Info about notifier function to be called
332 *
333 * Registers a function with the list of functions
334 * to be called at reboot time.
335 *
336 * Currently always returns zero, as blocking_notifier_chain_register()
337 * always returns zero.
338 */
339int register_reboot_notifier(struct notifier_block *nb)
340{
341 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
342}
343EXPORT_SYMBOL(register_reboot_notifier);
344
345/**
346 * unregister_reboot_notifier - Unregister previously registered reboot notifier
347 * @nb: Hook to be unregistered
348 *
349 * Unregisters a previously registered reboot
350 * notifier function.
351 *
352 * Returns zero on success, or %-ENOENT on failure.
353 */
354int unregister_reboot_notifier(struct notifier_block *nb)
355{
356 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
357}
358EXPORT_SYMBOL(unregister_reboot_notifier);
359
360/**
361 * kernel_restart - reboot the system
362 * @cmd: pointer to buffer containing command to execute for restart
363 * or %NULL
364 *
365 * Shutdown everything and perform a clean reboot.
366 * This is not safe to call in interrupt context.
367 */
368void kernel_restart(char *cmd)
369{
370 kernel_restart_prepare(cmd);
371 disable_nonboot_cpus();
372 if (!cmd)
373 printk(KERN_EMERG "Restarting system.\n");
374 else
375 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
376 kmsg_dump(KMSG_DUMP_RESTART);
377 machine_restart(cmd);
378}
379EXPORT_SYMBOL_GPL(kernel_restart);
380
381static void kernel_shutdown_prepare(enum system_states state)
382{
383 blocking_notifier_call_chain(&reboot_notifier_list,
384 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
385 system_state = state;
386 usermodehelper_disable();
387 device_shutdown();
388}
389/**
390 * kernel_halt - halt the system
391 *
392 * Shutdown everything and perform a clean system halt.
393 */
394void kernel_halt(void)
395{
396 kernel_shutdown_prepare(SYSTEM_HALT);
397 syscore_shutdown();
398 printk(KERN_EMERG "System halted.\n");
399 kmsg_dump(KMSG_DUMP_HALT);
400 machine_halt();
401}
402
403EXPORT_SYMBOL_GPL(kernel_halt);
404
405/**
406 * kernel_power_off - power_off the system
407 *
408 * Shutdown everything and perform a clean system power_off.
409 */
410void kernel_power_off(void)
411{
412 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
413 if (pm_power_off_prepare)
414 pm_power_off_prepare();
415 disable_nonboot_cpus();
416 syscore_shutdown();
417 printk(KERN_EMERG "Power down.\n");
418 kmsg_dump(KMSG_DUMP_POWEROFF);
419 machine_power_off();
420}
421EXPORT_SYMBOL_GPL(kernel_power_off);
422
423static DEFINE_MUTEX(reboot_mutex);
424
425/*
426 * Reboot system call: for obvious reasons only root may call it,
427 * and even root needs to set up some magic numbers in the registers
428 * so that some mistake won't make this reboot the whole machine.
429 * You can also set the meaning of the ctrl-alt-del-key here.
430 *
431 * reboot doesn't sync: do that yourself before calling this.
432 */
433SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
434 void __user *, arg)
435{
436 char buffer[256];
437 int ret = 0;
438
439 /* We only trust the superuser with rebooting the system. */
440 if (!capable(CAP_SYS_BOOT))
441 return -EPERM;
442
443 /* For safety, we require "magic" arguments. */
444 if (magic1 != LINUX_REBOOT_MAGIC1 ||
445 (magic2 != LINUX_REBOOT_MAGIC2 &&
446 magic2 != LINUX_REBOOT_MAGIC2A &&
447 magic2 != LINUX_REBOOT_MAGIC2B &&
448 magic2 != LINUX_REBOOT_MAGIC2C))
449 return -EINVAL;
450
451 /*
452 * If pid namespaces are enabled and the current task is in a child
453 * pid_namespace, the command is handled by reboot_pid_ns() which will
454 * call do_exit().
455 */
456 ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
457 if (ret)
458 return ret;
459
460 /* Instead of trying to make the power_off code look like
461 * halt when pm_power_off is not set do it the easy way.
462 */
463 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
464 cmd = LINUX_REBOOT_CMD_HALT;
465
466 mutex_lock(&reboot_mutex);
467 switch (cmd) {
468 case LINUX_REBOOT_CMD_RESTART:
469 kernel_restart(NULL);
470 break;
471
472 case LINUX_REBOOT_CMD_CAD_ON:
473 C_A_D = 1;
474 break;
475
476 case LINUX_REBOOT_CMD_CAD_OFF:
477 C_A_D = 0;
478 break;
479
480 case LINUX_REBOOT_CMD_HALT:
481 kernel_halt();
482 do_exit(0);
483 panic("cannot halt");
484
485 case LINUX_REBOOT_CMD_POWER_OFF:
486 kernel_power_off();
487 do_exit(0);
488 break;
489
490 case LINUX_REBOOT_CMD_RESTART2:
491 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
492 ret = -EFAULT;
493 break;
494 }
495 buffer[sizeof(buffer) - 1] = '\0';
496
497 kernel_restart(buffer);
498 break;
499
500#ifdef CONFIG_KEXEC
501 case LINUX_REBOOT_CMD_KEXEC:
502 ret = kernel_kexec();
503 break;
504#endif
505
506#ifdef CONFIG_HIBERNATION
507 case LINUX_REBOOT_CMD_SW_SUSPEND:
508 ret = hibernate();
509 break;
510#endif
511
512 default:
513 ret = -EINVAL;
514 break;
515 }
516 mutex_unlock(&reboot_mutex);
517 return ret;
518}
519
520static void deferred_cad(struct work_struct *dummy)
521{
522 kernel_restart(NULL);
523}
524
525/*
526 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
527 * As it's called within an interrupt, it may NOT sync: the only choice
528 * is whether to reboot at once, or just ignore the ctrl-alt-del.
529 */
530void ctrl_alt_del(void)
531{
532 static DECLARE_WORK(cad_work, deferred_cad);
533
534 if (C_A_D)
535 schedule_work(&cad_work);
536 else
537 kill_cad_pid(SIGINT, 1);
538}
539
540/*
541 * Unprivileged users may change the real gid to the effective gid
542 * or vice versa. (BSD-style)
543 *
544 * If you set the real gid at all, or set the effective gid to a value not
545 * equal to the real gid, then the saved gid is set to the new effective gid.
546 *
547 * This makes it possible for a setgid program to completely drop its
548 * privileges, which is often a useful assertion to make when you are doing
549 * a security audit over a program.
550 *
551 * The general idea is that a program which uses just setregid() will be
552 * 100% compatible with BSD. A program which uses just setgid() will be
553 * 100% compatible with POSIX with saved IDs.
554 *
555 * SMP: There are not races, the GIDs are checked only by filesystem
556 * operations (as far as semantic preservation is concerned).
557 */
558SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
559{
560 struct user_namespace *ns = current_user_ns();
561 const struct cred *old;
562 struct cred *new;
563 int retval;
564 kgid_t krgid, kegid;
565
566 krgid = make_kgid(ns, rgid);
567 kegid = make_kgid(ns, egid);
568
569 if ((rgid != (gid_t) -1) && !gid_valid(krgid))
570 return -EINVAL;
571 if ((egid != (gid_t) -1) && !gid_valid(kegid))
572 return -EINVAL;
573
574 new = prepare_creds();
575 if (!new)
576 return -ENOMEM;
577 old = current_cred();
578
579 retval = -EPERM;
580 if (rgid != (gid_t) -1) {
581 if (gid_eq(old->gid, krgid) ||
582 gid_eq(old->egid, krgid) ||
583 nsown_capable(CAP_SETGID))
584 new->gid = krgid;
585 else
586 goto error;
587 }
588 if (egid != (gid_t) -1) {
589 if (gid_eq(old->gid, kegid) ||
590 gid_eq(old->egid, kegid) ||
591 gid_eq(old->sgid, kegid) ||
592 nsown_capable(CAP_SETGID))
593 new->egid = kegid;
594 else
595 goto error;
596 }
597
598 if (rgid != (gid_t) -1 ||
599 (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
600 new->sgid = new->egid;
601 new->fsgid = new->egid;
602
603 return commit_creds(new);
604
605error:
606 abort_creds(new);
607 return retval;
608}
609
610/*
611 * setgid() is implemented like SysV w/ SAVED_IDS
612 *
613 * SMP: Same implicit races as above.
614 */
615SYSCALL_DEFINE1(setgid, gid_t, gid)
616{
617 struct user_namespace *ns = current_user_ns();
618 const struct cred *old;
619 struct cred *new;
620 int retval;
621 kgid_t kgid;
622
623 kgid = make_kgid(ns, gid);
624 if (!gid_valid(kgid))
625 return -EINVAL;
626
627 new = prepare_creds();
628 if (!new)
629 return -ENOMEM;
630 old = current_cred();
631
632 retval = -EPERM;
633 if (nsown_capable(CAP_SETGID))
634 new->gid = new->egid = new->sgid = new->fsgid = kgid;
635 else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
636 new->egid = new->fsgid = kgid;
637 else
638 goto error;
639
640 return commit_creds(new);
641
642error:
643 abort_creds(new);
644 return retval;
645}
646
647/*
648 * change the user struct in a credentials set to match the new UID
649 */
650static int set_user(struct cred *new)
651{
652 struct user_struct *new_user;
653
654 new_user = alloc_uid(new->uid);
655 if (!new_user)
656 return -EAGAIN;
657
658 /*
659 * We don't fail in case of NPROC limit excess here because too many
660 * poorly written programs don't check set*uid() return code, assuming
661 * it never fails if called by root. We may still enforce NPROC limit
662 * for programs doing set*uid()+execve() by harmlessly deferring the
663 * failure to the execve() stage.
664 */
665 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
666 new_user != INIT_USER)
667 current->flags |= PF_NPROC_EXCEEDED;
668 else
669 current->flags &= ~PF_NPROC_EXCEEDED;
670
671 free_uid(new->user);
672 new->user = new_user;
673 return 0;
674}
675
676/*
677 * Unprivileged users may change the real uid to the effective uid
678 * or vice versa. (BSD-style)
679 *
680 * If you set the real uid at all, or set the effective uid to a value not
681 * equal to the real uid, then the saved uid is set to the new effective uid.
682 *
683 * This makes it possible for a setuid program to completely drop its
684 * privileges, which is often a useful assertion to make when you are doing
685 * a security audit over a program.
686 *
687 * The general idea is that a program which uses just setreuid() will be
688 * 100% compatible with BSD. A program which uses just setuid() will be
689 * 100% compatible with POSIX with saved IDs.
690 */
691SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
692{
693 struct user_namespace *ns = current_user_ns();
694 const struct cred *old;
695 struct cred *new;
696 int retval;
697 kuid_t kruid, keuid;
698
699 kruid = make_kuid(ns, ruid);
700 keuid = make_kuid(ns, euid);
701
702 if ((ruid != (uid_t) -1) && !uid_valid(kruid))
703 return -EINVAL;
704 if ((euid != (uid_t) -1) && !uid_valid(keuid))
705 return -EINVAL;
706
707 new = prepare_creds();
708 if (!new)
709 return -ENOMEM;
710 old = current_cred();
711
712 retval = -EPERM;
713 if (ruid != (uid_t) -1) {
714 new->uid = kruid;
715 if (!uid_eq(old->uid, kruid) &&
716 !uid_eq(old->euid, kruid) &&
717 !nsown_capable(CAP_SETUID))
718 goto error;
719 }
720
721 if (euid != (uid_t) -1) {
722 new->euid = keuid;
723 if (!uid_eq(old->uid, keuid) &&
724 !uid_eq(old->euid, keuid) &&
725 !uid_eq(old->suid, keuid) &&
726 !nsown_capable(CAP_SETUID))
727 goto error;
728 }
729
730 if (!uid_eq(new->uid, old->uid)) {
731 retval = set_user(new);
732 if (retval < 0)
733 goto error;
734 }
735 if (ruid != (uid_t) -1 ||
736 (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
737 new->suid = new->euid;
738 new->fsuid = new->euid;
739
740 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
741 if (retval < 0)
742 goto error;
743
744 return commit_creds(new);
745
746error:
747 abort_creds(new);
748 return retval;
749}
750
751/*
752 * setuid() is implemented like SysV with SAVED_IDS
753 *
754 * Note that SAVED_ID's is deficient in that a setuid root program
755 * like sendmail, for example, cannot set its uid to be a normal
756 * user and then switch back, because if you're root, setuid() sets
757 * the saved uid too. If you don't like this, blame the bright people
758 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
759 * will allow a root program to temporarily drop privileges and be able to
760 * regain them by swapping the real and effective uid.
761 */
762SYSCALL_DEFINE1(setuid, uid_t, uid)
763{
764 struct user_namespace *ns = current_user_ns();
765 const struct cred *old;
766 struct cred *new;
767 int retval;
768 kuid_t kuid;
769
770 kuid = make_kuid(ns, uid);
771 if (!uid_valid(kuid))
772 return -EINVAL;
773
774 new = prepare_creds();
775 if (!new)
776 return -ENOMEM;
777 old = current_cred();
778
779 retval = -EPERM;
780 if (nsown_capable(CAP_SETUID)) {
781 new->suid = new->uid = kuid;
782 if (!uid_eq(kuid, old->uid)) {
783 retval = set_user(new);
784 if (retval < 0)
785 goto error;
786 }
787 } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
788 goto error;
789 }
790
791 new->fsuid = new->euid = kuid;
792
793 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
794 if (retval < 0)
795 goto error;
796
797 return commit_creds(new);
798
799error:
800 abort_creds(new);
801 return retval;
802}
803
804
805/*
806 * This function implements a generic ability to update ruid, euid,
807 * and suid. This allows you to implement the 4.4 compatible seteuid().
808 */
809SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
810{
811 struct user_namespace *ns = current_user_ns();
812 const struct cred *old;
813 struct cred *new;
814 int retval;
815 kuid_t kruid, keuid, ksuid;
816
817 kruid = make_kuid(ns, ruid);
818 keuid = make_kuid(ns, euid);
819 ksuid = make_kuid(ns, suid);
820
821 if ((ruid != (uid_t) -1) && !uid_valid(kruid))
822 return -EINVAL;
823
824 if ((euid != (uid_t) -1) && !uid_valid(keuid))
825 return -EINVAL;
826
827 if ((suid != (uid_t) -1) && !uid_valid(ksuid))
828 return -EINVAL;
829
830 new = prepare_creds();
831 if (!new)
832 return -ENOMEM;
833
834 old = current_cred();
835
836 retval = -EPERM;
837 if (!nsown_capable(CAP_SETUID)) {
838 if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
839 !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
840 goto error;
841 if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) &&
842 !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
843 goto error;
844 if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) &&
845 !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
846 goto error;
847 }
848
849 if (ruid != (uid_t) -1) {
850 new->uid = kruid;
851 if (!uid_eq(kruid, old->uid)) {
852 retval = set_user(new);
853 if (retval < 0)
854 goto error;
855 }
856 }
857 if (euid != (uid_t) -1)
858 new->euid = keuid;
859 if (suid != (uid_t) -1)
860 new->suid = ksuid;
861 new->fsuid = new->euid;
862
863 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
864 if (retval < 0)
865 goto error;
866
867 return commit_creds(new);
868
869error:
870 abort_creds(new);
871 return retval;
872}
873
874SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
875{
876 const struct cred *cred = current_cred();
877 int retval;
878 uid_t ruid, euid, suid;
879
880 ruid = from_kuid_munged(cred->user_ns, cred->uid);
881 euid = from_kuid_munged(cred->user_ns, cred->euid);
882 suid = from_kuid_munged(cred->user_ns, cred->suid);
883
884 if (!(retval = put_user(ruid, ruidp)) &&
885 !(retval = put_user(euid, euidp)))
886 retval = put_user(suid, suidp);
887
888 return retval;
889}
890
891/*
892 * Same as above, but for rgid, egid, sgid.
893 */
894SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
895{
896 struct user_namespace *ns = current_user_ns();
897 const struct cred *old;
898 struct cred *new;
899 int retval;
900 kgid_t krgid, kegid, ksgid;
901
902 krgid = make_kgid(ns, rgid);
903 kegid = make_kgid(ns, egid);
904 ksgid = make_kgid(ns, sgid);
905
906 if ((rgid != (gid_t) -1) && !gid_valid(krgid))
907 return -EINVAL;
908 if ((egid != (gid_t) -1) && !gid_valid(kegid))
909 return -EINVAL;
910 if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
911 return -EINVAL;
912
913 new = prepare_creds();
914 if (!new)
915 return -ENOMEM;
916 old = current_cred();
917
918 retval = -EPERM;
919 if (!nsown_capable(CAP_SETGID)) {
920 if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
921 !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
922 goto error;
923 if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) &&
924 !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
925 goto error;
926 if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) &&
927 !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
928 goto error;
929 }
930
931 if (rgid != (gid_t) -1)
932 new->gid = krgid;
933 if (egid != (gid_t) -1)
934 new->egid = kegid;
935 if (sgid != (gid_t) -1)
936 new->sgid = ksgid;
937 new->fsgid = new->egid;
938
939 return commit_creds(new);
940
941error:
942 abort_creds(new);
943 return retval;
944}
945
946SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
947{
948 const struct cred *cred = current_cred();
949 int retval;
950 gid_t rgid, egid, sgid;
951
952 rgid = from_kgid_munged(cred->user_ns, cred->gid);
953 egid = from_kgid_munged(cred->user_ns, cred->egid);
954 sgid = from_kgid_munged(cred->user_ns, cred->sgid);
955
956 if (!(retval = put_user(rgid, rgidp)) &&
957 !(retval = put_user(egid, egidp)))
958 retval = put_user(sgid, sgidp);
959
960 return retval;
961}
962
963
964/*
965 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
966 * is used for "access()" and for the NFS daemon (letting nfsd stay at
967 * whatever uid it wants to). It normally shadows "euid", except when
968 * explicitly set by setfsuid() or for access..
969 */
970SYSCALL_DEFINE1(setfsuid, uid_t, uid)
971{
972 const struct cred *old;
973 struct cred *new;
974 uid_t old_fsuid;
975 kuid_t kuid;
976
977 old = current_cred();
978 old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
979
980 kuid = make_kuid(old->user_ns, uid);
981 if (!uid_valid(kuid))
982 return old_fsuid;
983
984 new = prepare_creds();
985 if (!new)
986 return old_fsuid;
987
988 if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) ||
989 uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
990 nsown_capable(CAP_SETUID)) {
991 if (!uid_eq(kuid, old->fsuid)) {
992 new->fsuid = kuid;
993 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
994 goto change_okay;
995 }
996 }
997
998 abort_creds(new);
999 return old_fsuid;
1000
1001change_okay:
1002 commit_creds(new);
1003 return old_fsuid;
1004}
1005
1006/*
1007 * Samma på svenska..
1008 */
1009SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1010{
1011 const struct cred *old;
1012 struct cred *new;
1013 gid_t old_fsgid;
1014 kgid_t kgid;
1015
1016 old = current_cred();
1017 old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1018
1019 kgid = make_kgid(old->user_ns, gid);
1020 if (!gid_valid(kgid))
1021 return old_fsgid;
1022
1023 new = prepare_creds();
1024 if (!new)
1025 return old_fsgid;
1026
1027 if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
1028 gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1029 nsown_capable(CAP_SETGID)) {
1030 if (!gid_eq(kgid, old->fsgid)) {
1031 new->fsgid = kgid;
1032 goto change_okay;
1033 }
1034 }
1035
1036 abort_creds(new);
1037 return old_fsgid;
1038
1039change_okay:
1040 commit_creds(new);
1041 return old_fsgid;
1042}
1043
1044void do_sys_times(struct tms *tms)
1045{
1046 cputime_t tgutime, tgstime, cutime, cstime;
1047
1048 spin_lock_irq(&current->sighand->siglock);
1049 thread_group_times(current, &tgutime, &tgstime);
1050 cutime = current->signal->cutime;
1051 cstime = current->signal->cstime;
1052 spin_unlock_irq(&current->sighand->siglock);
1053 tms->tms_utime = cputime_to_clock_t(tgutime);
1054 tms->tms_stime = cputime_to_clock_t(tgstime);
1055 tms->tms_cutime = cputime_to_clock_t(cutime);
1056 tms->tms_cstime = cputime_to_clock_t(cstime);
1057}
1058
1059SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1060{
1061 if (tbuf) {
1062 struct tms tmp;
1063
1064 do_sys_times(&tmp);
1065 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1066 return -EFAULT;
1067 }
1068 force_successful_syscall_return();
1069 return (long) jiffies_64_to_clock_t(get_jiffies_64());
1070}
1071
1072/*
1073 * This needs some heavy checking ...
1074 * I just haven't the stomach for it. I also don't fully
1075 * understand sessions/pgrp etc. Let somebody who does explain it.
1076 *
1077 * OK, I think I have the protection semantics right.... this is really
1078 * only important on a multi-user system anyway, to make sure one user
1079 * can't send a signal to a process owned by another. -TYT, 12/12/91
1080 *
1081 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1082 * LBT 04.03.94
1083 */
1084SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1085{
1086 struct task_struct *p;
1087 struct task_struct *group_leader = current->group_leader;
1088 struct pid *pgrp;
1089 int err;
1090
1091 if (!pid)
1092 pid = task_pid_vnr(group_leader);
1093 if (!pgid)
1094 pgid = pid;
1095 if (pgid < 0)
1096 return -EINVAL;
1097 rcu_read_lock();
1098
1099 /* From this point forward we keep holding onto the tasklist lock
1100 * so that our parent does not change from under us. -DaveM
1101 */
1102 write_lock_irq(&tasklist_lock);
1103
1104 err = -ESRCH;
1105 p = find_task_by_vpid(pid);
1106 if (!p)
1107 goto out;
1108
1109 err = -EINVAL;
1110 if (!thread_group_leader(p))
1111 goto out;
1112
1113 if (same_thread_group(p->real_parent, group_leader)) {
1114 err = -EPERM;
1115 if (task_session(p) != task_session(group_leader))
1116 goto out;
1117 err = -EACCES;
1118 if (p->did_exec)
1119 goto out;
1120 } else {
1121 err = -ESRCH;
1122 if (p != group_leader)
1123 goto out;
1124 }
1125
1126 err = -EPERM;
1127 if (p->signal->leader)
1128 goto out;
1129
1130 pgrp = task_pid(p);
1131 if (pgid != pid) {
1132 struct task_struct *g;
1133
1134 pgrp = find_vpid(pgid);
1135 g = pid_task(pgrp, PIDTYPE_PGID);
1136 if (!g || task_session(g) != task_session(group_leader))
1137 goto out;
1138 }
1139
1140 err = security_task_setpgid(p, pgid);
1141 if (err)
1142 goto out;
1143
1144 if (task_pgrp(p) != pgrp)
1145 change_pid(p, PIDTYPE_PGID, pgrp);
1146
1147 err = 0;
1148out:
1149 /* All paths lead to here, thus we are safe. -DaveM */
1150 write_unlock_irq(&tasklist_lock);
1151 rcu_read_unlock();
1152 return err;
1153}
1154
1155SYSCALL_DEFINE1(getpgid, pid_t, pid)
1156{
1157 struct task_struct *p;
1158 struct pid *grp;
1159 int retval;
1160
1161 rcu_read_lock();
1162 if (!pid)
1163 grp = task_pgrp(current);
1164 else {
1165 retval = -ESRCH;
1166 p = find_task_by_vpid(pid);
1167 if (!p)
1168 goto out;
1169 grp = task_pgrp(p);
1170 if (!grp)
1171 goto out;
1172
1173 retval = security_task_getpgid(p);
1174 if (retval)
1175 goto out;
1176 }
1177 retval = pid_vnr(grp);
1178out:
1179 rcu_read_unlock();
1180 return retval;
1181}
1182
1183#ifdef __ARCH_WANT_SYS_GETPGRP
1184
1185SYSCALL_DEFINE0(getpgrp)
1186{
1187 return sys_getpgid(0);
1188}
1189
1190#endif
1191
1192SYSCALL_DEFINE1(getsid, pid_t, pid)
1193{
1194 struct task_struct *p;
1195 struct pid *sid;
1196 int retval;
1197
1198 rcu_read_lock();
1199 if (!pid)
1200 sid = task_session(current);
1201 else {
1202 retval = -ESRCH;
1203 p = find_task_by_vpid(pid);
1204 if (!p)
1205 goto out;
1206 sid = task_session(p);
1207 if (!sid)
1208 goto out;
1209
1210 retval = security_task_getsid(p);
1211 if (retval)
1212 goto out;
1213 }
1214 retval = pid_vnr(sid);
1215out:
1216 rcu_read_unlock();
1217 return retval;
1218}
1219
1220SYSCALL_DEFINE0(setsid)
1221{
1222 struct task_struct *group_leader = current->group_leader;
1223 struct pid *sid = task_pid(group_leader);
1224 pid_t session = pid_vnr(sid);
1225 int err = -EPERM;
1226
1227 write_lock_irq(&tasklist_lock);
1228 /* Fail if I am already a session leader */
1229 if (group_leader->signal->leader)
1230 goto out;
1231
1232 /* Fail if a process group id already exists that equals the
1233 * proposed session id.
1234 */
1235 if (pid_task(sid, PIDTYPE_PGID))
1236 goto out;
1237
1238 group_leader->signal->leader = 1;
1239 __set_special_pids(sid);
1240
1241 proc_clear_tty(group_leader);
1242
1243 err = session;
1244out:
1245 write_unlock_irq(&tasklist_lock);
1246 if (err > 0) {
1247 proc_sid_connector(group_leader);
1248 sched_autogroup_create_attach(group_leader);
1249 }
1250 return err;
1251}
1252
1253DECLARE_RWSEM(uts_sem);
1254
1255#ifdef COMPAT_UTS_MACHINE
1256#define override_architecture(name) \
1257 (personality(current->personality) == PER_LINUX32 && \
1258 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1259 sizeof(COMPAT_UTS_MACHINE)))
1260#else
1261#define override_architecture(name) 0
1262#endif
1263
1264/*
1265 * Work around broken programs that cannot handle "Linux 3.0".
1266 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1267 */
1268static int override_release(char __user *release, size_t len)
1269{
1270 int ret = 0;
1271
1272 if (current->personality & UNAME26) {
1273 const char *rest = UTS_RELEASE;
1274 char buf[65] = { 0 };
1275 int ndots = 0;
1276 unsigned v;
1277 size_t copy;
1278
1279 while (*rest) {
1280 if (*rest == '.' && ++ndots >= 3)
1281 break;
1282 if (!isdigit(*rest) && *rest != '.')
1283 break;
1284 rest++;
1285 }
1286 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1287 copy = clamp_t(size_t, len, 1, sizeof(buf));
1288 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1289 ret = copy_to_user(release, buf, copy + 1);
1290 }
1291 return ret;
1292}
1293
1294SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1295{
1296 int errno = 0;
1297
1298 down_read(&uts_sem);
1299 if (copy_to_user(name, utsname(), sizeof *name))
1300 errno = -EFAULT;
1301 up_read(&uts_sem);
1302
1303 if (!errno && override_release(name->release, sizeof(name->release)))
1304 errno = -EFAULT;
1305 if (!errno && override_architecture(name))
1306 errno = -EFAULT;
1307 return errno;
1308}
1309
1310#ifdef __ARCH_WANT_SYS_OLD_UNAME
1311/*
1312 * Old cruft
1313 */
1314SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1315{
1316 int error = 0;
1317
1318 if (!name)
1319 return -EFAULT;
1320
1321 down_read(&uts_sem);
1322 if (copy_to_user(name, utsname(), sizeof(*name)))
1323 error = -EFAULT;
1324 up_read(&uts_sem);
1325
1326 if (!error && override_release(name->release, sizeof(name->release)))
1327 error = -EFAULT;
1328 if (!error && override_architecture(name))
1329 error = -EFAULT;
1330 return error;
1331}
1332
1333SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1334{
1335 int error;
1336
1337 if (!name)
1338 return -EFAULT;
1339 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1340 return -EFAULT;
1341
1342 down_read(&uts_sem);
1343 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1344 __OLD_UTS_LEN);
1345 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1346 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1347 __OLD_UTS_LEN);
1348 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1349 error |= __copy_to_user(&name->release, &utsname()->release,
1350 __OLD_UTS_LEN);
1351 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1352 error |= __copy_to_user(&name->version, &utsname()->version,
1353 __OLD_UTS_LEN);
1354 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1355 error |= __copy_to_user(&name->machine, &utsname()->machine,
1356 __OLD_UTS_LEN);
1357 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1358 up_read(&uts_sem);
1359
1360 if (!error && override_architecture(name))
1361 error = -EFAULT;
1362 if (!error && override_release(name->release, sizeof(name->release)))
1363 error = -EFAULT;
1364 return error ? -EFAULT : 0;
1365}
1366#endif
1367
1368SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1369{
1370 int errno;
1371 char tmp[__NEW_UTS_LEN];
1372
1373 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1374 return -EPERM;
1375
1376 if (len < 0 || len > __NEW_UTS_LEN)
1377 return -EINVAL;
1378 down_write(&uts_sem);
1379 errno = -EFAULT;
1380 if (!copy_from_user(tmp, name, len)) {
1381 struct new_utsname *u = utsname();
1382
1383 memcpy(u->nodename, tmp, len);
1384 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1385 errno = 0;
1386 uts_proc_notify(UTS_PROC_HOSTNAME);
1387 }
1388 up_write(&uts_sem);
1389 return errno;
1390}
1391
1392#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1393
1394SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1395{
1396 int i, errno;
1397 struct new_utsname *u;
1398
1399 if (len < 0)
1400 return -EINVAL;
1401 down_read(&uts_sem);
1402 u = utsname();
1403 i = 1 + strlen(u->nodename);
1404 if (i > len)
1405 i = len;
1406 errno = 0;
1407 if (copy_to_user(name, u->nodename, i))
1408 errno = -EFAULT;
1409 up_read(&uts_sem);
1410 return errno;
1411}
1412
1413#endif
1414
1415/*
1416 * Only setdomainname; getdomainname can be implemented by calling
1417 * uname()
1418 */
1419SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1420{
1421 int errno;
1422 char tmp[__NEW_UTS_LEN];
1423
1424 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1425 return -EPERM;
1426 if (len < 0 || len > __NEW_UTS_LEN)
1427 return -EINVAL;
1428
1429 down_write(&uts_sem);
1430 errno = -EFAULT;
1431 if (!copy_from_user(tmp, name, len)) {
1432 struct new_utsname *u = utsname();
1433
1434 memcpy(u->domainname, tmp, len);
1435 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1436 errno = 0;
1437 uts_proc_notify(UTS_PROC_DOMAINNAME);
1438 }
1439 up_write(&uts_sem);
1440 return errno;
1441}
1442
1443SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1444{
1445 struct rlimit value;
1446 int ret;
1447
1448 ret = do_prlimit(current, resource, NULL, &value);
1449 if (!ret)
1450 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1451
1452 return ret;
1453}
1454
1455#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1456
1457/*
1458 * Back compatibility for getrlimit. Needed for some apps.
1459 */
1460
1461SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1462 struct rlimit __user *, rlim)
1463{
1464 struct rlimit x;
1465 if (resource >= RLIM_NLIMITS)
1466 return -EINVAL;
1467
1468 task_lock(current->group_leader);
1469 x = current->signal->rlim[resource];
1470 task_unlock(current->group_leader);
1471 if (x.rlim_cur > 0x7FFFFFFF)
1472 x.rlim_cur = 0x7FFFFFFF;
1473 if (x.rlim_max > 0x7FFFFFFF)
1474 x.rlim_max = 0x7FFFFFFF;
1475 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1476}
1477
1478#endif
1479
1480static inline bool rlim64_is_infinity(__u64 rlim64)
1481{
1482#if BITS_PER_LONG < 64
1483 return rlim64 >= ULONG_MAX;
1484#else
1485 return rlim64 == RLIM64_INFINITY;
1486#endif
1487}
1488
1489static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1490{
1491 if (rlim->rlim_cur == RLIM_INFINITY)
1492 rlim64->rlim_cur = RLIM64_INFINITY;
1493 else
1494 rlim64->rlim_cur = rlim->rlim_cur;
1495 if (rlim->rlim_max == RLIM_INFINITY)
1496 rlim64->rlim_max = RLIM64_INFINITY;
1497 else
1498 rlim64->rlim_max = rlim->rlim_max;
1499}
1500
1501static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1502{
1503 if (rlim64_is_infinity(rlim64->rlim_cur))
1504 rlim->rlim_cur = RLIM_INFINITY;
1505 else
1506 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1507 if (rlim64_is_infinity(rlim64->rlim_max))
1508 rlim->rlim_max = RLIM_INFINITY;
1509 else
1510 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1511}
1512
1513/* make sure you are allowed to change @tsk limits before calling this */
1514int do_prlimit(struct task_struct *tsk, unsigned int resource,
1515 struct rlimit *new_rlim, struct rlimit *old_rlim)
1516{
1517 struct rlimit *rlim;
1518 int retval = 0;
1519
1520 if (resource >= RLIM_NLIMITS)
1521 return -EINVAL;
1522 if (new_rlim) {
1523 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1524 return -EINVAL;
1525 if (resource == RLIMIT_NOFILE &&
1526 new_rlim->rlim_max > sysctl_nr_open)
1527 return -EPERM;
1528 }
1529
1530 /* protect tsk->signal and tsk->sighand from disappearing */
1531 read_lock(&tasklist_lock);
1532 if (!tsk->sighand) {
1533 retval = -ESRCH;
1534 goto out;
1535 }
1536
1537 rlim = tsk->signal->rlim + resource;
1538 task_lock(tsk->group_leader);
1539 if (new_rlim) {
1540 /* Keep the capable check against init_user_ns until
1541 cgroups can contain all limits */
1542 if (new_rlim->rlim_max > rlim->rlim_max &&
1543 !capable(CAP_SYS_RESOURCE))
1544 retval = -EPERM;
1545 if (!retval)
1546 retval = security_task_setrlimit(tsk->group_leader,
1547 resource, new_rlim);
1548 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1549 /*
1550 * The caller is asking for an immediate RLIMIT_CPU
1551 * expiry. But we use the zero value to mean "it was
1552 * never set". So let's cheat and make it one second
1553 * instead
1554 */
1555 new_rlim->rlim_cur = 1;
1556 }
1557 }
1558 if (!retval) {
1559 if (old_rlim)
1560 *old_rlim = *rlim;
1561 if (new_rlim)
1562 *rlim = *new_rlim;
1563 }
1564 task_unlock(tsk->group_leader);
1565
1566 /*
1567 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1568 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1569 * very long-standing error, and fixing it now risks breakage of
1570 * applications, so we live with it
1571 */
1572 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1573 new_rlim->rlim_cur != RLIM_INFINITY)
1574 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1575out:
1576 read_unlock(&tasklist_lock);
1577 return retval;
1578}
1579
1580/* rcu lock must be held */
1581static int check_prlimit_permission(struct task_struct *task)
1582{
1583 const struct cred *cred = current_cred(), *tcred;
1584
1585 if (current == task)
1586 return 0;
1587
1588 tcred = __task_cred(task);
1589 if (uid_eq(cred->uid, tcred->euid) &&
1590 uid_eq(cred->uid, tcred->suid) &&
1591 uid_eq(cred->uid, tcred->uid) &&
1592 gid_eq(cred->gid, tcred->egid) &&
1593 gid_eq(cred->gid, tcred->sgid) &&
1594 gid_eq(cred->gid, tcred->gid))
1595 return 0;
1596 if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1597 return 0;
1598
1599 return -EPERM;
1600}
1601
1602SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1603 const struct rlimit64 __user *, new_rlim,
1604 struct rlimit64 __user *, old_rlim)
1605{
1606 struct rlimit64 old64, new64;
1607 struct rlimit old, new;
1608 struct task_struct *tsk;
1609 int ret;
1610
1611 if (new_rlim) {
1612 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1613 return -EFAULT;
1614 rlim64_to_rlim(&new64, &new);
1615 }
1616
1617 rcu_read_lock();
1618 tsk = pid ? find_task_by_vpid(pid) : current;
1619 if (!tsk) {
1620 rcu_read_unlock();
1621 return -ESRCH;
1622 }
1623 ret = check_prlimit_permission(tsk);
1624 if (ret) {
1625 rcu_read_unlock();
1626 return ret;
1627 }
1628 get_task_struct(tsk);
1629 rcu_read_unlock();
1630
1631 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1632 old_rlim ? &old : NULL);
1633
1634 if (!ret && old_rlim) {
1635 rlim_to_rlim64(&old, &old64);
1636 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1637 ret = -EFAULT;
1638 }
1639
1640 put_task_struct(tsk);
1641 return ret;
1642}
1643
1644SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1645{
1646 struct rlimit new_rlim;
1647
1648 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1649 return -EFAULT;
1650 return do_prlimit(current, resource, &new_rlim, NULL);
1651}
1652
1653/*
1654 * It would make sense to put struct rusage in the task_struct,
1655 * except that would make the task_struct be *really big*. After
1656 * task_struct gets moved into malloc'ed memory, it would
1657 * make sense to do this. It will make moving the rest of the information
1658 * a lot simpler! (Which we're not doing right now because we're not
1659 * measuring them yet).
1660 *
1661 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1662 * races with threads incrementing their own counters. But since word
1663 * reads are atomic, we either get new values or old values and we don't
1664 * care which for the sums. We always take the siglock to protect reading
1665 * the c* fields from p->signal from races with exit.c updating those
1666 * fields when reaping, so a sample either gets all the additions of a
1667 * given child after it's reaped, or none so this sample is before reaping.
1668 *
1669 * Locking:
1670 * We need to take the siglock for CHILDEREN, SELF and BOTH
1671 * for the cases current multithreaded, non-current single threaded
1672 * non-current multithreaded. Thread traversal is now safe with
1673 * the siglock held.
1674 * Strictly speaking, we donot need to take the siglock if we are current and
1675 * single threaded, as no one else can take our signal_struct away, no one
1676 * else can reap the children to update signal->c* counters, and no one else
1677 * can race with the signal-> fields. If we do not take any lock, the
1678 * signal-> fields could be read out of order while another thread was just
1679 * exiting. So we should place a read memory barrier when we avoid the lock.
1680 * On the writer side, write memory barrier is implied in __exit_signal
1681 * as __exit_signal releases the siglock spinlock after updating the signal->
1682 * fields. But we don't do this yet to keep things simple.
1683 *
1684 */
1685
1686static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1687{
1688 r->ru_nvcsw += t->nvcsw;
1689 r->ru_nivcsw += t->nivcsw;
1690 r->ru_minflt += t->min_flt;
1691 r->ru_majflt += t->maj_flt;
1692 r->ru_inblock += task_io_get_inblock(t);
1693 r->ru_oublock += task_io_get_oublock(t);
1694}
1695
1696static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1697{
1698 struct task_struct *t;
1699 unsigned long flags;
1700 cputime_t tgutime, tgstime, utime, stime;
1701 unsigned long maxrss = 0;
1702
1703 memset((char *) r, 0, sizeof *r);
1704 utime = stime = 0;
1705
1706 if (who == RUSAGE_THREAD) {
1707 task_times(current, &utime, &stime);
1708 accumulate_thread_rusage(p, r);
1709 maxrss = p->signal->maxrss;
1710 goto out;
1711 }
1712
1713 if (!lock_task_sighand(p, &flags))
1714 return;
1715
1716 switch (who) {
1717 case RUSAGE_BOTH:
1718 case RUSAGE_CHILDREN:
1719 utime = p->signal->cutime;
1720 stime = p->signal->cstime;
1721 r->ru_nvcsw = p->signal->cnvcsw;
1722 r->ru_nivcsw = p->signal->cnivcsw;
1723 r->ru_minflt = p->signal->cmin_flt;
1724 r->ru_majflt = p->signal->cmaj_flt;
1725 r->ru_inblock = p->signal->cinblock;
1726 r->ru_oublock = p->signal->coublock;
1727 maxrss = p->signal->cmaxrss;
1728
1729 if (who == RUSAGE_CHILDREN)
1730 break;
1731
1732 case RUSAGE_SELF:
1733 thread_group_times(p, &tgutime, &tgstime);
1734 utime += tgutime;
1735 stime += tgstime;
1736 r->ru_nvcsw += p->signal->nvcsw;
1737 r->ru_nivcsw += p->signal->nivcsw;
1738 r->ru_minflt += p->signal->min_flt;
1739 r->ru_majflt += p->signal->maj_flt;
1740 r->ru_inblock += p->signal->inblock;
1741 r->ru_oublock += p->signal->oublock;
1742 if (maxrss < p->signal->maxrss)
1743 maxrss = p->signal->maxrss;
1744 t = p;
1745 do {
1746 accumulate_thread_rusage(t, r);
1747 t = next_thread(t);
1748 } while (t != p);
1749 break;
1750
1751 default:
1752 BUG();
1753 }
1754 unlock_task_sighand(p, &flags);
1755
1756out:
1757 cputime_to_timeval(utime, &r->ru_utime);
1758 cputime_to_timeval(stime, &r->ru_stime);
1759
1760 if (who != RUSAGE_CHILDREN) {
1761 struct mm_struct *mm = get_task_mm(p);
1762 if (mm) {
1763 setmax_mm_hiwater_rss(&maxrss, mm);
1764 mmput(mm);
1765 }
1766 }
1767 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1768}
1769
1770int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1771{
1772 struct rusage r;
1773 k_getrusage(p, who, &r);
1774 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1775}
1776
1777SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1778{
1779 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1780 who != RUSAGE_THREAD)
1781 return -EINVAL;
1782 return getrusage(current, who, ru);
1783}
1784
1785SYSCALL_DEFINE1(umask, int, mask)
1786{
1787 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1788 return mask;
1789}
1790
1791#ifdef CONFIG_CHECKPOINT_RESTORE
1792static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1793{
1794 struct fd exe;
1795 struct dentry *dentry;
1796 int err;
1797
1798 exe = fdget(fd);
1799 if (!exe.file)
1800 return -EBADF;
1801
1802 dentry = exe.file->f_path.dentry;
1803
1804 /*
1805 * Because the original mm->exe_file points to executable file, make
1806 * sure that this one is executable as well, to avoid breaking an
1807 * overall picture.
1808 */
1809 err = -EACCES;
1810 if (!S_ISREG(dentry->d_inode->i_mode) ||
1811 exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1812 goto exit;
1813
1814 err = inode_permission(dentry->d_inode, MAY_EXEC);
1815 if (err)
1816 goto exit;
1817
1818 down_write(&mm->mmap_sem);
1819
1820 /*
1821 * Forbid mm->exe_file change if old file still mapped.
1822 */
1823 err = -EBUSY;
1824 if (mm->exe_file) {
1825 struct vm_area_struct *vma;
1826
1827 for (vma = mm->mmap; vma; vma = vma->vm_next)
1828 if (vma->vm_file &&
1829 path_equal(&vma->vm_file->f_path,
1830 &mm->exe_file->f_path))
1831 goto exit_unlock;
1832 }
1833
1834 /*
1835 * The symlink can be changed only once, just to disallow arbitrary
1836 * transitions malicious software might bring in. This means one
1837 * could make a snapshot over all processes running and monitor
1838 * /proc/pid/exe changes to notice unusual activity if needed.
1839 */
1840 err = -EPERM;
1841 if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1842 goto exit_unlock;
1843
1844 err = 0;
1845 set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */
1846exit_unlock:
1847 up_write(&mm->mmap_sem);
1848
1849exit:
1850 fdput(exe);
1851 return err;
1852}
1853
1854static int prctl_set_mm(int opt, unsigned long addr,
1855 unsigned long arg4, unsigned long arg5)
1856{
1857 unsigned long rlim = rlimit(RLIMIT_DATA);
1858 struct mm_struct *mm = current->mm;
1859 struct vm_area_struct *vma;
1860 int error;
1861
1862 if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1863 return -EINVAL;
1864
1865 if (!capable(CAP_SYS_RESOURCE))
1866 return -EPERM;
1867
1868 if (opt == PR_SET_MM_EXE_FILE)
1869 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1870
1871 if (addr >= TASK_SIZE || addr < mmap_min_addr)
1872 return -EINVAL;
1873
1874 error = -EINVAL;
1875
1876 down_read(&mm->mmap_sem);
1877 vma = find_vma(mm, addr);
1878
1879 switch (opt) {
1880 case PR_SET_MM_START_CODE:
1881 mm->start_code = addr;
1882 break;
1883 case PR_SET_MM_END_CODE:
1884 mm->end_code = addr;
1885 break;
1886 case PR_SET_MM_START_DATA:
1887 mm->start_data = addr;
1888 break;
1889 case PR_SET_MM_END_DATA:
1890 mm->end_data = addr;
1891 break;
1892
1893 case PR_SET_MM_START_BRK:
1894 if (addr <= mm->end_data)
1895 goto out;
1896
1897 if (rlim < RLIM_INFINITY &&
1898 (mm->brk - addr) +
1899 (mm->end_data - mm->start_data) > rlim)
1900 goto out;
1901
1902 mm->start_brk = addr;
1903 break;
1904
1905 case PR_SET_MM_BRK:
1906 if (addr <= mm->end_data)
1907 goto out;
1908
1909 if (rlim < RLIM_INFINITY &&
1910 (addr - mm->start_brk) +
1911 (mm->end_data - mm->start_data) > rlim)
1912 goto out;
1913
1914 mm->brk = addr;
1915 break;
1916
1917 /*
1918 * If command line arguments and environment
1919 * are placed somewhere else on stack, we can
1920 * set them up here, ARG_START/END to setup
1921 * command line argumets and ENV_START/END
1922 * for environment.
1923 */
1924 case PR_SET_MM_START_STACK:
1925 case PR_SET_MM_ARG_START:
1926 case PR_SET_MM_ARG_END:
1927 case PR_SET_MM_ENV_START:
1928 case PR_SET_MM_ENV_END:
1929 if (!vma) {
1930 error = -EFAULT;
1931 goto out;
1932 }
1933 if (opt == PR_SET_MM_START_STACK)
1934 mm->start_stack = addr;
1935 else if (opt == PR_SET_MM_ARG_START)
1936 mm->arg_start = addr;
1937 else if (opt == PR_SET_MM_ARG_END)
1938 mm->arg_end = addr;
1939 else if (opt == PR_SET_MM_ENV_START)
1940 mm->env_start = addr;
1941 else if (opt == PR_SET_MM_ENV_END)
1942 mm->env_end = addr;
1943 break;
1944
1945 /*
1946 * This doesn't move auxiliary vector itself
1947 * since it's pinned to mm_struct, but allow
1948 * to fill vector with new values. It's up
1949 * to a caller to provide sane values here
1950 * otherwise user space tools which use this
1951 * vector might be unhappy.
1952 */
1953 case PR_SET_MM_AUXV: {
1954 unsigned long user_auxv[AT_VECTOR_SIZE];
1955
1956 if (arg4 > sizeof(user_auxv))
1957 goto out;
1958 up_read(&mm->mmap_sem);
1959
1960 if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1961 return -EFAULT;
1962
1963 /* Make sure the last entry is always AT_NULL */
1964 user_auxv[AT_VECTOR_SIZE - 2] = 0;
1965 user_auxv[AT_VECTOR_SIZE - 1] = 0;
1966
1967 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1968
1969 task_lock(current);
1970 memcpy(mm->saved_auxv, user_auxv, arg4);
1971 task_unlock(current);
1972
1973 return 0;
1974 }
1975 default:
1976 goto out;
1977 }
1978
1979 error = 0;
1980out:
1981 up_read(&mm->mmap_sem);
1982 return error;
1983}
1984
1985static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1986{
1987 return put_user(me->clear_child_tid, tid_addr);
1988}
1989
1990#else /* CONFIG_CHECKPOINT_RESTORE */
1991static int prctl_set_mm(int opt, unsigned long addr,
1992 unsigned long arg4, unsigned long arg5)
1993{
1994 return -EINVAL;
1995}
1996static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1997{
1998 return -EINVAL;
1999}
2000#endif
2001
2002SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2003 unsigned long, arg4, unsigned long, arg5)
2004{
2005 struct task_struct *me = current;
2006 unsigned char comm[sizeof(me->comm)];
2007 long error;
2008
2009 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2010 if (error != -ENOSYS)
2011 return error;
2012
2013 error = 0;
2014 switch (option) {
2015 case PR_SET_PDEATHSIG:
2016 if (!valid_signal(arg2)) {
2017 error = -EINVAL;
2018 break;
2019 }
2020 me->pdeath_signal = arg2;
2021 break;
2022 case PR_GET_PDEATHSIG:
2023 error = put_user(me->pdeath_signal, (int __user *)arg2);
2024 break;
2025 case PR_GET_DUMPABLE:
2026 error = get_dumpable(me->mm);
2027 break;
2028 case PR_SET_DUMPABLE:
2029 if (arg2 < 0 || arg2 > 1) {
2030 error = -EINVAL;
2031 break;
2032 }
2033 set_dumpable(me->mm, arg2);
2034 break;
2035
2036 case PR_SET_UNALIGN:
2037 error = SET_UNALIGN_CTL(me, arg2);
2038 break;
2039 case PR_GET_UNALIGN:
2040 error = GET_UNALIGN_CTL(me, arg2);
2041 break;
2042 case PR_SET_FPEMU:
2043 error = SET_FPEMU_CTL(me, arg2);
2044 break;
2045 case PR_GET_FPEMU:
2046 error = GET_FPEMU_CTL(me, arg2);
2047 break;
2048 case PR_SET_FPEXC:
2049 error = SET_FPEXC_CTL(me, arg2);
2050 break;
2051 case PR_GET_FPEXC:
2052 error = GET_FPEXC_CTL(me, arg2);
2053 break;
2054 case PR_GET_TIMING:
2055 error = PR_TIMING_STATISTICAL;
2056 break;
2057 case PR_SET_TIMING:
2058 if (arg2 != PR_TIMING_STATISTICAL)
2059 error = -EINVAL;
2060 break;
2061 case PR_SET_NAME:
2062 comm[sizeof(me->comm)-1] = 0;
2063 if (strncpy_from_user(comm, (char __user *)arg2,
2064 sizeof(me->comm) - 1) < 0)
2065 return -EFAULT;
2066 set_task_comm(me, comm);
2067 proc_comm_connector(me);
2068 break;
2069 case PR_GET_NAME:
2070 get_task_comm(comm, me);
2071 if (copy_to_user((char __user *)arg2, comm,
2072 sizeof(comm)))
2073 return -EFAULT;
2074 break;
2075 case PR_GET_ENDIAN:
2076 error = GET_ENDIAN(me, arg2);
2077 break;
2078 case PR_SET_ENDIAN:
2079 error = SET_ENDIAN(me, arg2);
2080 break;
2081 case PR_GET_SECCOMP:
2082 error = prctl_get_seccomp();
2083 break;
2084 case PR_SET_SECCOMP:
2085 error = prctl_set_seccomp(arg2, (char __user *)arg3);
2086 break;
2087 case PR_GET_TSC:
2088 error = GET_TSC_CTL(arg2);
2089 break;
2090 case PR_SET_TSC:
2091 error = SET_TSC_CTL(arg2);
2092 break;
2093 case PR_TASK_PERF_EVENTS_DISABLE:
2094 error = perf_event_task_disable();
2095 break;
2096 case PR_TASK_PERF_EVENTS_ENABLE:
2097 error = perf_event_task_enable();
2098 break;
2099 case PR_GET_TIMERSLACK:
2100 error = current->timer_slack_ns;
2101 break;
2102 case PR_SET_TIMERSLACK:
2103 if (arg2 <= 0)
2104 current->timer_slack_ns =
2105 current->default_timer_slack_ns;
2106 else
2107 current->timer_slack_ns = arg2;
2108 break;
2109 case PR_MCE_KILL:
2110 if (arg4 | arg5)
2111 return -EINVAL;
2112 switch (arg2) {
2113 case PR_MCE_KILL_CLEAR:
2114 if (arg3 != 0)
2115 return -EINVAL;
2116 current->flags &= ~PF_MCE_PROCESS;
2117 break;
2118 case PR_MCE_KILL_SET:
2119 current->flags |= PF_MCE_PROCESS;
2120 if (arg3 == PR_MCE_KILL_EARLY)
2121 current->flags |= PF_MCE_EARLY;
2122 else if (arg3 == PR_MCE_KILL_LATE)
2123 current->flags &= ~PF_MCE_EARLY;
2124 else if (arg3 == PR_MCE_KILL_DEFAULT)
2125 current->flags &=
2126 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2127 else
2128 return -EINVAL;
2129 break;
2130 default:
2131 return -EINVAL;
2132 }
2133 break;
2134 case PR_MCE_KILL_GET:
2135 if (arg2 | arg3 | arg4 | arg5)
2136 return -EINVAL;
2137 if (current->flags & PF_MCE_PROCESS)
2138 error = (current->flags & PF_MCE_EARLY) ?
2139 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2140 else
2141 error = PR_MCE_KILL_DEFAULT;
2142 break;
2143 case PR_SET_MM:
2144 error = prctl_set_mm(arg2, arg3, arg4, arg5);
2145 break;
2146 case PR_GET_TID_ADDRESS:
2147 error = prctl_get_tid_address(me, (int __user **)arg2);
2148 break;
2149 case PR_SET_CHILD_SUBREAPER:
2150 me->signal->is_child_subreaper = !!arg2;
2151 break;
2152 case PR_GET_CHILD_SUBREAPER:
2153 error = put_user(me->signal->is_child_subreaper,
2154 (int __user *) arg2);
2155 break;
2156 case PR_SET_NO_NEW_PRIVS:
2157 if (arg2 != 1 || arg3 || arg4 || arg5)
2158 return -EINVAL;
2159
2160 current->no_new_privs = 1;
2161 break;
2162 case PR_GET_NO_NEW_PRIVS:
2163 if (arg2 || arg3 || arg4 || arg5)
2164 return -EINVAL;
2165 return current->no_new_privs ? 1 : 0;
2166 default:
2167 error = -EINVAL;
2168 break;
2169 }
2170 return error;
2171}
2172
2173SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2174 struct getcpu_cache __user *, unused)
2175{
2176 int err = 0;
2177 int cpu = raw_smp_processor_id();
2178 if (cpup)
2179 err |= put_user(cpu, cpup);
2180 if (nodep)
2181 err |= put_user(cpu_to_node(cpu), nodep);
2182 return err ? -EFAULT : 0;
2183}
2184
2185char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2186
2187static void argv_cleanup(struct subprocess_info *info)
2188{
2189 argv_free(info->argv);
2190}
2191
2192static int __orderly_poweroff(void)
2193{
2194 int argc;
2195 char **argv;
2196 static char *envp[] = {
2197 "HOME=/",
2198 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2199 NULL
2200 };
2201 int ret;
2202
2203 argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2204 if (argv == NULL) {
2205 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2206 __func__, poweroff_cmd);
2207 return -ENOMEM;
2208 }
2209
2210 ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_WAIT_EXEC,
2211 NULL, argv_cleanup, NULL);
2212 if (ret == -ENOMEM)
2213 argv_free(argv);
2214
2215 return ret;
2216}
2217
2218/**
2219 * orderly_poweroff - Trigger an orderly system poweroff
2220 * @force: force poweroff if command execution fails
2221 *
2222 * This may be called from any context to trigger a system shutdown.
2223 * If the orderly shutdown fails, it will force an immediate shutdown.
2224 */
2225int orderly_poweroff(bool force)
2226{
2227 int ret = __orderly_poweroff();
2228
2229 if (ret && force) {
2230 printk(KERN_WARNING "Failed to start orderly shutdown: "
2231 "forcing the issue\n");
2232
2233 /*
2234 * I guess this should try to kick off some daemon to sync and
2235 * poweroff asap. Or not even bother syncing if we're doing an
2236 * emergency shutdown?
2237 */
2238 emergency_sync();
2239 kernel_power_off();
2240 }
2241
2242 return ret;
2243}
2244EXPORT_SYMBOL_GPL(orderly_poweroff);