projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
ipv4: Fix ip_getsockopt for IP_PKTOPTIONS
[deliverable/linux.git] / 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/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/perf_event.h>
16 #include <linux/resource.h>
17 #include <linux/kernel.h>
18 #include <linux/kexec.h>
19 #include <linux/workqueue.h>
20 #include <linux/capability.h>
21 #include <linux/device.h>
22 #include <linux/key.h>
23 #include <linux/times.h>
24 #include <linux/posix-timers.h>
25 #include <linux/security.h>
26 #include <linux/dcookies.h>
27 #include <linux/suspend.h>
28 #include <linux/tty.h>
29 #include <linux/signal.h>
30 #include <linux/cn_proc.h>
31 #include <linux/getcpu.h>
32 #include <linux/task_io_accounting_ops.h>
33 #include <linux/seccomp.h>
34 #include <linux/cpu.h>
35 #include <linux/personality.h>
36 #include <linux/ptrace.h>
37 #include <linux/fs_struct.h>
38 #include <linux/gfp.h>
39 #include <linux/syscore_ops.h>
40
41 #include <linux/compat.h>
42 #include <linux/syscalls.h>
43 #include <linux/kprobes.h>
44 #include <linux/user_namespace.h>
45
46 #include <linux/kmsg_dump.h>
47
48 #include <asm/uaccess.h>
49 #include <asm/io.h>
50 #include <asm/unistd.h>
51
52 #ifndef SET_UNALIGN_CTL
53 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
54 #endif
55 #ifndef GET_UNALIGN_CTL
56 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
57 #endif
58 #ifndef SET_FPEMU_CTL
59 # define SET_FPEMU_CTL(a,b) (-EINVAL)
60 #endif
61 #ifndef GET_FPEMU_CTL
62 # define GET_FPEMU_CTL(a,b) (-EINVAL)
63 #endif
64 #ifndef SET_FPEXC_CTL
65 # define SET_FPEXC_CTL(a,b) (-EINVAL)
66 #endif
67 #ifndef GET_FPEXC_CTL
68 # define GET_FPEXC_CTL(a,b) (-EINVAL)
69 #endif
70 #ifndef GET_ENDIAN
71 # define GET_ENDIAN(a,b) (-EINVAL)
72 #endif
73 #ifndef SET_ENDIAN
74 # define SET_ENDIAN(a,b) (-EINVAL)
75 #endif
76 #ifndef GET_TSC_CTL
77 # define GET_TSC_CTL(a) (-EINVAL)
78 #endif
79 #ifndef SET_TSC_CTL
80 # define SET_TSC_CTL(a) (-EINVAL)
81 #endif
82
83 /*
84 * this is where the system-wide overflow UID and GID are defined, for
85 * architectures that now have 32-bit UID/GID but didn't in the past
86 */
87
88 int overflowuid = DEFAULT_OVERFLOWUID;
89 int overflowgid = DEFAULT_OVERFLOWGID;
90
91 #ifdef CONFIG_UID16
92 EXPORT_SYMBOL(overflowuid);
93 EXPORT_SYMBOL(overflowgid);
94 #endif
95
96 /*
97 * the same as above, but for filesystems which can only store a 16-bit
98 * UID and GID. as such, this is needed on all architectures
99 */
100
101 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
102 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
103
104 EXPORT_SYMBOL(fs_overflowuid);
105 EXPORT_SYMBOL(fs_overflowgid);
106
107 /*
108 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
109 */
110
111 int C_A_D = 1;
112 struct pid *cad_pid;
113 EXPORT_SYMBOL(cad_pid);
114
115 /*
116 * If set, this is used for preparing the system to power off.
117 */
118
119 void (*pm_power_off_prepare)(void);
120
121 /*
122 * Returns true if current's euid is same as p's uid or euid,
123 * or has CAP_SYS_NICE to p's user_ns.
124 *
125 * Called with rcu_read_lock, creds are safe
126 */
127 static bool set_one_prio_perm(struct task_struct *p)
128 {
129 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
130
131 if (pcred->user->user_ns == cred->user->user_ns &&
132 (pcred->uid == cred->euid ||
133 pcred->euid == cred->euid))
134 return true;
135 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
136 return true;
137 return false;
138 }
139
140 /*
141 * set the priority of a task
142 * - the caller must hold the RCU read lock
143 */
144 static int set_one_prio(struct task_struct *p, int niceval, int error)
145 {
146 int no_nice;
147
148 if (!set_one_prio_perm(p)) {
149 error = -EPERM;
150 goto out;
151 }
152 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
153 error = -EACCES;
154 goto out;
155 }
156 no_nice = security_task_setnice(p, niceval);
157 if (no_nice) {
158 error = no_nice;
159 goto out;
160 }
161 if (error == -ESRCH)
162 error = 0;
163 set_user_nice(p, niceval);
164 out:
165 return error;
166 }
167
168 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
169 {
170 struct task_struct *g, *p;
171 struct user_struct *user;
172 const struct cred *cred = current_cred();
173 int error = -EINVAL;
174 struct pid *pgrp;
175
176 if (which > PRIO_USER || which < PRIO_PROCESS)
177 goto out;
178
179 /* normalize: avoid signed division (rounding problems) */
180 error = -ESRCH;
181 if (niceval < -20)
182 niceval = -20;
183 if (niceval > 19)
184 niceval = 19;
185
186 rcu_read_lock();
187 read_lock(&tasklist_lock);
188 switch (which) {
189 case PRIO_PROCESS:
190 if (who)
191 p = find_task_by_vpid(who);
192 else
193 p = current;
194 if (p)
195 error = set_one_prio(p, niceval, error);
196 break;
197 case PRIO_PGRP:
198 if (who)
199 pgrp = find_vpid(who);
200 else
201 pgrp = task_pgrp(current);
202 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
203 error = set_one_prio(p, niceval, error);
204 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
205 break;
206 case PRIO_USER:
207 user = (struct user_struct *) cred->user;
208 if (!who)
209 who = cred->uid;
210 else if ((who != cred->uid) &&
211 !(user = find_user(who)))
212 goto out_unlock; /* No processes for this user */
213
214 do_each_thread(g, p) {
215 if (__task_cred(p)->uid == who)
216 error = set_one_prio(p, niceval, error);
217 } while_each_thread(g, p);
218 if (who != cred->uid)
219 free_uid(user); /* For find_user() */
220 break;
221 }
222 out_unlock:
223 read_unlock(&tasklist_lock);
224 rcu_read_unlock();
225 out:
226 return error;
227 }
228
229 /*
230 * Ugh. To avoid negative return values, "getpriority()" will
231 * not return the normal nice-value, but a negated value that
232 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
233 * to stay compatible.
234 */
235 SYSCALL_DEFINE2(getpriority, int, which, int, who)
236 {
237 struct task_struct *g, *p;
238 struct user_struct *user;
239 const struct cred *cred = current_cred();
240 long niceval, retval = -ESRCH;
241 struct pid *pgrp;
242
243 if (which > PRIO_USER || which < PRIO_PROCESS)
244 return -EINVAL;
245
246 rcu_read_lock();
247 read_lock(&tasklist_lock);
248 switch (which) {
249 case PRIO_PROCESS:
250 if (who)
251 p = find_task_by_vpid(who);
252 else
253 p = current;
254 if (p) {
255 niceval = 20 - task_nice(p);
256 if (niceval > retval)
257 retval = niceval;
258 }
259 break;
260 case PRIO_PGRP:
261 if (who)
262 pgrp = find_vpid(who);
263 else
264 pgrp = task_pgrp(current);
265 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
266 niceval = 20 - task_nice(p);
267 if (niceval > retval)
268 retval = niceval;
269 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
270 break;
271 case PRIO_USER:
272 user = (struct user_struct *) cred->user;
273 if (!who)
274 who = cred->uid;
275 else if ((who != cred->uid) &&
276 !(user = find_user(who)))
277 goto out_unlock; /* No processes for this user */
278
279 do_each_thread(g, p) {
280 if (__task_cred(p)->uid == who) {
281 niceval = 20 - task_nice(p);
282 if (niceval > retval)
283 retval = niceval;
284 }
285 } while_each_thread(g, p);
286 if (who != cred->uid)
287 free_uid(user); /* for find_user() */
288 break;
289 }
290 out_unlock:
291 read_unlock(&tasklist_lock);
292 rcu_read_unlock();
293
294 return retval;
295 }
296
297 /**
298 * emergency_restart - reboot the system
299 *
300 * Without shutting down any hardware or taking any locks
301 * reboot the system. This is called when we know we are in
302 * trouble so this is our best effort to reboot. This is
303 * safe to call in interrupt context.
304 */
305 void emergency_restart(void)
306 {
307 kmsg_dump(KMSG_DUMP_EMERG);
308 machine_emergency_restart();
309 }
310 EXPORT_SYMBOL_GPL(emergency_restart);
311
312 void kernel_restart_prepare(char *cmd)
313 {
314 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
315 system_state = SYSTEM_RESTART;
316 usermodehelper_disable();
317 device_shutdown();
318 syscore_shutdown();
319 }
320
321 /**
322 * register_reboot_notifier - Register function to be called at reboot time
323 * @nb: Info about notifier function to be called
324 *
325 * Registers a function with the list of functions
326 * to be called at reboot time.
327 *
328 * Currently always returns zero, as blocking_notifier_chain_register()
329 * always returns zero.
330 */
331 int register_reboot_notifier(struct notifier_block *nb)
332 {
333 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
334 }
335 EXPORT_SYMBOL(register_reboot_notifier);
336
337 /**
338 * unregister_reboot_notifier - Unregister previously registered reboot notifier
339 * @nb: Hook to be unregistered
340 *
341 * Unregisters a previously registered reboot
342 * notifier function.
343 *
344 * Returns zero on success, or %-ENOENT on failure.
345 */
346 int unregister_reboot_notifier(struct notifier_block *nb)
347 {
348 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
349 }
350 EXPORT_SYMBOL(unregister_reboot_notifier);
351
352 /**
353 * kernel_restart - reboot the system
354 * @cmd: pointer to buffer containing command to execute for restart
355 * or %NULL
356 *
357 * Shutdown everything and perform a clean reboot.
358 * This is not safe to call in interrupt context.
359 */
360 void kernel_restart(char *cmd)
361 {
362 kernel_restart_prepare(cmd);
363 if (!cmd)
364 printk(KERN_EMERG "Restarting system.\n");
365 else
366 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
367 kmsg_dump(KMSG_DUMP_RESTART);
368 machine_restart(cmd);
369 }
370 EXPORT_SYMBOL_GPL(kernel_restart);
371
372 static void kernel_shutdown_prepare(enum system_states state)
373 {
374 blocking_notifier_call_chain(&reboot_notifier_list,
375 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
376 system_state = state;
377 usermodehelper_disable();
378 device_shutdown();
379 }
380 /**
381 * kernel_halt - halt the system
382 *
383 * Shutdown everything and perform a clean system halt.
384 */
385 void kernel_halt(void)
386 {
387 kernel_shutdown_prepare(SYSTEM_HALT);
388 syscore_shutdown();
389 printk(KERN_EMERG "System halted.\n");
390 kmsg_dump(KMSG_DUMP_HALT);
391 machine_halt();
392 }
393
394 EXPORT_SYMBOL_GPL(kernel_halt);
395
396 /**
397 * kernel_power_off - power_off the system
398 *
399 * Shutdown everything and perform a clean system power_off.
400 */
401 void kernel_power_off(void)
402 {
403 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
404 if (pm_power_off_prepare)
405 pm_power_off_prepare();
406 disable_nonboot_cpus();
407 syscore_shutdown();
408 printk(KERN_EMERG "Power down.\n");
409 kmsg_dump(KMSG_DUMP_POWEROFF);
410 machine_power_off();
411 }
412 EXPORT_SYMBOL_GPL(kernel_power_off);
413
414 static DEFINE_MUTEX(reboot_mutex);
415
416 /*
417 * Reboot system call: for obvious reasons only root may call it,
418 * and even root needs to set up some magic numbers in the registers
419 * so that some mistake won't make this reboot the whole machine.
420 * You can also set the meaning of the ctrl-alt-del-key here.
421 *
422 * reboot doesn't sync: do that yourself before calling this.
423 */
424 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
425 void __user *, arg)
426 {
427 char buffer[256];
428 int ret = 0;
429
430 /* We only trust the superuser with rebooting the system. */
431 if (!capable(CAP_SYS_BOOT))
432 return -EPERM;
433
434 /* For safety, we require "magic" arguments. */
435 if (magic1 != LINUX_REBOOT_MAGIC1 ||
436 (magic2 != LINUX_REBOOT_MAGIC2 &&
437 magic2 != LINUX_REBOOT_MAGIC2A &&
438 magic2 != LINUX_REBOOT_MAGIC2B &&
439 magic2 != LINUX_REBOOT_MAGIC2C))
440 return -EINVAL;
441
442 /* Instead of trying to make the power_off code look like
443 * halt when pm_power_off is not set do it the easy way.
444 */
445 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
446 cmd = LINUX_REBOOT_CMD_HALT;
447
448 mutex_lock(&reboot_mutex);
449 switch (cmd) {
450 case LINUX_REBOOT_CMD_RESTART:
451 kernel_restart(NULL);
452 break;
453
454 case LINUX_REBOOT_CMD_CAD_ON:
455 C_A_D = 1;
456 break;
457
458 case LINUX_REBOOT_CMD_CAD_OFF:
459 C_A_D = 0;
460 break;
461
462 case LINUX_REBOOT_CMD_HALT:
463 kernel_halt();
464 do_exit(0);
465 panic("cannot halt");
466
467 case LINUX_REBOOT_CMD_POWER_OFF:
468 kernel_power_off();
469 do_exit(0);
470 break;
471
472 case LINUX_REBOOT_CMD_RESTART2:
473 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
474 ret = -EFAULT;
475 break;
476 }
477 buffer[sizeof(buffer) - 1] = '\0';
478
479 kernel_restart(buffer);
480 break;
481
482 #ifdef CONFIG_KEXEC
483 case LINUX_REBOOT_CMD_KEXEC:
484 ret = kernel_kexec();
485 break;
486 #endif
487
488 #ifdef CONFIG_HIBERNATION
489 case LINUX_REBOOT_CMD_SW_SUSPEND:
490 ret = hibernate();
491 break;
492 #endif
493
494 default:
495 ret = -EINVAL;
496 break;
497 }
498 mutex_unlock(&reboot_mutex);
499 return ret;
500 }
501
502 static void deferred_cad(struct work_struct *dummy)
503 {
504 kernel_restart(NULL);
505 }
506
507 /*
508 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
509 * As it's called within an interrupt, it may NOT sync: the only choice
510 * is whether to reboot at once, or just ignore the ctrl-alt-del.
511 */
512 void ctrl_alt_del(void)
513 {
514 static DECLARE_WORK(cad_work, deferred_cad);
515
516 if (C_A_D)
517 schedule_work(&cad_work);
518 else
519 kill_cad_pid(SIGINT, 1);
520 }
521
522 /*
523 * Unprivileged users may change the real gid to the effective gid
524 * or vice versa. (BSD-style)
525 *
526 * If you set the real gid at all, or set the effective gid to a value not
527 * equal to the real gid, then the saved gid is set to the new effective gid.
528 *
529 * This makes it possible for a setgid program to completely drop its
530 * privileges, which is often a useful assertion to make when you are doing
531 * a security audit over a program.
532 *
533 * The general idea is that a program which uses just setregid() will be
534 * 100% compatible with BSD. A program which uses just setgid() will be
535 * 100% compatible with POSIX with saved IDs.
536 *
537 * SMP: There are not races, the GIDs are checked only by filesystem
538 * operations (as far as semantic preservation is concerned).
539 */
540 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
541 {
542 const struct cred *old;
543 struct cred *new;
544 int retval;
545
546 new = prepare_creds();
547 if (!new)
548 return -ENOMEM;
549 old = current_cred();
550
551 retval = -EPERM;
552 if (rgid != (gid_t) -1) {
553 if (old->gid == rgid ||
554 old->egid == rgid ||
555 nsown_capable(CAP_SETGID))
556 new->gid = rgid;
557 else
558 goto error;
559 }
560 if (egid != (gid_t) -1) {
561 if (old->gid == egid ||
562 old->egid == egid ||
563 old->sgid == egid ||
564 nsown_capable(CAP_SETGID))
565 new->egid = egid;
566 else
567 goto error;
568 }
569
570 if (rgid != (gid_t) -1 ||
571 (egid != (gid_t) -1 && egid != old->gid))
572 new->sgid = new->egid;
573 new->fsgid = new->egid;
574
575 return commit_creds(new);
576
577 error:
578 abort_creds(new);
579 return retval;
580 }
581
582 /*
583 * setgid() is implemented like SysV w/ SAVED_IDS
584 *
585 * SMP: Same implicit races as above.
586 */
587 SYSCALL_DEFINE1(setgid, gid_t, gid)
588 {
589 const struct cred *old;
590 struct cred *new;
591 int retval;
592
593 new = prepare_creds();
594 if (!new)
595 return -ENOMEM;
596 old = current_cred();
597
598 retval = -EPERM;
599 if (nsown_capable(CAP_SETGID))
600 new->gid = new->egid = new->sgid = new->fsgid = gid;
601 else if (gid == old->gid || gid == old->sgid)
602 new->egid = new->fsgid = gid;
603 else
604 goto error;
605
606 return commit_creds(new);
607
608 error:
609 abort_creds(new);
610 return retval;
611 }
612
613 /*
614 * change the user struct in a credentials set to match the new UID
615 */
616 static int set_user(struct cred *new)
617 {
618 struct user_struct *new_user;
619
620 new_user = alloc_uid(current_user_ns(), new->uid);
621 if (!new_user)
622 return -EAGAIN;
623
624 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
625 new_user != INIT_USER) {
626 free_uid(new_user);
627 return -EAGAIN;
628 }
629
630 free_uid(new->user);
631 new->user = new_user;
632 return 0;
633 }
634
635 /*
636 * Unprivileged users may change the real uid to the effective uid
637 * or vice versa. (BSD-style)
638 *
639 * If you set the real uid at all, or set the effective uid to a value not
640 * equal to the real uid, then the saved uid is set to the new effective uid.
641 *
642 * This makes it possible for a setuid program to completely drop its
643 * privileges, which is often a useful assertion to make when you are doing
644 * a security audit over a program.
645 *
646 * The general idea is that a program which uses just setreuid() will be
647 * 100% compatible with BSD. A program which uses just setuid() will be
648 * 100% compatible with POSIX with saved IDs.
649 */
650 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
651 {
652 const struct cred *old;
653 struct cred *new;
654 int retval;
655
656 new = prepare_creds();
657 if (!new)
658 return -ENOMEM;
659 old = current_cred();
660
661 retval = -EPERM;
662 if (ruid != (uid_t) -1) {
663 new->uid = ruid;
664 if (old->uid != ruid &&
665 old->euid != ruid &&
666 !nsown_capable(CAP_SETUID))
667 goto error;
668 }
669
670 if (euid != (uid_t) -1) {
671 new->euid = euid;
672 if (old->uid != euid &&
673 old->euid != euid &&
674 old->suid != euid &&
675 !nsown_capable(CAP_SETUID))
676 goto error;
677 }
678
679 if (new->uid != old->uid) {
680 retval = set_user(new);
681 if (retval < 0)
682 goto error;
683 }
684 if (ruid != (uid_t) -1 ||
685 (euid != (uid_t) -1 && euid != old->uid))
686 new->suid = new->euid;
687 new->fsuid = new->euid;
688
689 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
690 if (retval < 0)
691 goto error;
692
693 return commit_creds(new);
694
695 error:
696 abort_creds(new);
697 return retval;
698 }
699
700 /*
701 * setuid() is implemented like SysV with SAVED_IDS
702 *
703 * Note that SAVED_ID's is deficient in that a setuid root program
704 * like sendmail, for example, cannot set its uid to be a normal
705 * user and then switch back, because if you're root, setuid() sets
706 * the saved uid too. If you don't like this, blame the bright people
707 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
708 * will allow a root program to temporarily drop privileges and be able to
709 * regain them by swapping the real and effective uid.
710 */
711 SYSCALL_DEFINE1(setuid, uid_t, uid)
712 {
713 const struct cred *old;
714 struct cred *new;
715 int retval;
716
717 new = prepare_creds();
718 if (!new)
719 return -ENOMEM;
720 old = current_cred();
721
722 retval = -EPERM;
723 if (nsown_capable(CAP_SETUID)) {
724 new->suid = new->uid = uid;
725 if (uid != old->uid) {
726 retval = set_user(new);
727 if (retval < 0)
728 goto error;
729 }
730 } else if (uid != old->uid && uid != new->suid) {
731 goto error;
732 }
733
734 new->fsuid = new->euid = uid;
735
736 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
737 if (retval < 0)
738 goto error;
739
740 return commit_creds(new);
741
742 error:
743 abort_creds(new);
744 return retval;
745 }
746
747
748 /*
749 * This function implements a generic ability to update ruid, euid,
750 * and suid. This allows you to implement the 4.4 compatible seteuid().
751 */
752 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
753 {
754 const struct cred *old;
755 struct cred *new;
756 int retval;
757
758 new = prepare_creds();
759 if (!new)
760 return -ENOMEM;
761
762 old = current_cred();
763
764 retval = -EPERM;
765 if (!nsown_capable(CAP_SETUID)) {
766 if (ruid != (uid_t) -1 && ruid != old->uid &&
767 ruid != old->euid && ruid != old->suid)
768 goto error;
769 if (euid != (uid_t) -1 && euid != old->uid &&
770 euid != old->euid && euid != old->suid)
771 goto error;
772 if (suid != (uid_t) -1 && suid != old->uid &&
773 suid != old->euid && suid != old->suid)
774 goto error;
775 }
776
777 if (ruid != (uid_t) -1) {
778 new->uid = ruid;
779 if (ruid != old->uid) {
780 retval = set_user(new);
781 if (retval < 0)
782 goto error;
783 }
784 }
785 if (euid != (uid_t) -1)
786 new->euid = euid;
787 if (suid != (uid_t) -1)
788 new->suid = suid;
789 new->fsuid = new->euid;
790
791 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
792 if (retval < 0)
793 goto error;
794
795 return commit_creds(new);
796
797 error:
798 abort_creds(new);
799 return retval;
800 }
801
802 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
803 {
804 const struct cred *cred = current_cred();
805 int retval;
806
807 if (!(retval = put_user(cred->uid, ruid)) &&
808 !(retval = put_user(cred->euid, euid)))
809 retval = put_user(cred->suid, suid);
810
811 return retval;
812 }
813
814 /*
815 * Same as above, but for rgid, egid, sgid.
816 */
817 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
818 {
819 const struct cred *old;
820 struct cred *new;
821 int retval;
822
823 new = prepare_creds();
824 if (!new)
825 return -ENOMEM;
826 old = current_cred();
827
828 retval = -EPERM;
829 if (!nsown_capable(CAP_SETGID)) {
830 if (rgid != (gid_t) -1 && rgid != old->gid &&
831 rgid != old->egid && rgid != old->sgid)
832 goto error;
833 if (egid != (gid_t) -1 && egid != old->gid &&
834 egid != old->egid && egid != old->sgid)
835 goto error;
836 if (sgid != (gid_t) -1 && sgid != old->gid &&
837 sgid != old->egid && sgid != old->sgid)
838 goto error;
839 }
840
841 if (rgid != (gid_t) -1)
842 new->gid = rgid;
843 if (egid != (gid_t) -1)
844 new->egid = egid;
845 if (sgid != (gid_t) -1)
846 new->sgid = sgid;
847 new->fsgid = new->egid;
848
849 return commit_creds(new);
850
851 error:
852 abort_creds(new);
853 return retval;
854 }
855
856 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
857 {
858 const struct cred *cred = current_cred();
859 int retval;
860
861 if (!(retval = put_user(cred->gid, rgid)) &&
862 !(retval = put_user(cred->egid, egid)))
863 retval = put_user(cred->sgid, sgid);
864
865 return retval;
866 }
867
868
869 /*
870 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
871 * is used for "access()" and for the NFS daemon (letting nfsd stay at
872 * whatever uid it wants to). It normally shadows "euid", except when
873 * explicitly set by setfsuid() or for access..
874 */
875 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
876 {
877 const struct cred *old;
878 struct cred *new;
879 uid_t old_fsuid;
880
881 new = prepare_creds();
882 if (!new)
883 return current_fsuid();
884 old = current_cred();
885 old_fsuid = old->fsuid;
886
887 if (uid == old->uid || uid == old->euid ||
888 uid == old->suid || uid == old->fsuid ||
889 nsown_capable(CAP_SETUID)) {
890 if (uid != old_fsuid) {
891 new->fsuid = uid;
892 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
893 goto change_okay;
894 }
895 }
896
897 abort_creds(new);
898 return old_fsuid;
899
900 change_okay:
901 commit_creds(new);
902 return old_fsuid;
903 }
904
905 /*
906 * Samma på svenska..
907 */
908 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
909 {
910 const struct cred *old;
911 struct cred *new;
912 gid_t old_fsgid;
913
914 new = prepare_creds();
915 if (!new)
916 return current_fsgid();
917 old = current_cred();
918 old_fsgid = old->fsgid;
919
920 if (gid == old->gid || gid == old->egid ||
921 gid == old->sgid || gid == old->fsgid ||
922 nsown_capable(CAP_SETGID)) {
923 if (gid != old_fsgid) {
924 new->fsgid = gid;
925 goto change_okay;
926 }
927 }
928
929 abort_creds(new);
930 return old_fsgid;
931
932 change_okay:
933 commit_creds(new);
934 return old_fsgid;
935 }
936
937 void do_sys_times(struct tms *tms)
938 {
939 cputime_t tgutime, tgstime, cutime, cstime;
940
941 spin_lock_irq(&current->sighand->siglock);
942 thread_group_times(current, &tgutime, &tgstime);
943 cutime = current->signal->cutime;
944 cstime = current->signal->cstime;
945 spin_unlock_irq(&current->sighand->siglock);
946 tms->tms_utime = cputime_to_clock_t(tgutime);
947 tms->tms_stime = cputime_to_clock_t(tgstime);
948 tms->tms_cutime = cputime_to_clock_t(cutime);
949 tms->tms_cstime = cputime_to_clock_t(cstime);
950 }
951
952 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
953 {
954 if (tbuf) {
955 struct tms tmp;
956
957 do_sys_times(&tmp);
958 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
959 return -EFAULT;
960 }
961 force_successful_syscall_return();
962 return (long) jiffies_64_to_clock_t(get_jiffies_64());
963 }
964
965 /*
966 * This needs some heavy checking ...
967 * I just haven't the stomach for it. I also don't fully
968 * understand sessions/pgrp etc. Let somebody who does explain it.
969 *
970 * OK, I think I have the protection semantics right.... this is really
971 * only important on a multi-user system anyway, to make sure one user
972 * can't send a signal to a process owned by another. -TYT, 12/12/91
973 *
974 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
975 * LBT 04.03.94
976 */
977 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
978 {
979 struct task_struct *p;
980 struct task_struct *group_leader = current->group_leader;
981 struct pid *pgrp;
982 int err;
983
984 if (!pid)
985 pid = task_pid_vnr(group_leader);
986 if (!pgid)
987 pgid = pid;
988 if (pgid < 0)
989 return -EINVAL;
990 rcu_read_lock();
991
992 /* From this point forward we keep holding onto the tasklist lock
993 * so that our parent does not change from under us. -DaveM
994 */
995 write_lock_irq(&tasklist_lock);
996
997 err = -ESRCH;
998 p = find_task_by_vpid(pid);
999 if (!p)
1000 goto out;
1001
1002 err = -EINVAL;
1003 if (!thread_group_leader(p))
1004 goto out;
1005
1006 if (same_thread_group(p->real_parent, group_leader)) {
1007 err = -EPERM;
1008 if (task_session(p) != task_session(group_leader))
1009 goto out;
1010 err = -EACCES;
1011 if (p->did_exec)
1012 goto out;
1013 } else {
1014 err = -ESRCH;
1015 if (p != group_leader)
1016 goto out;
1017 }
1018
1019 err = -EPERM;
1020 if (p->signal->leader)
1021 goto out;
1022
1023 pgrp = task_pid(p);
1024 if (pgid != pid) {
1025 struct task_struct *g;
1026
1027 pgrp = find_vpid(pgid);
1028 g = pid_task(pgrp, PIDTYPE_PGID);
1029 if (!g || task_session(g) != task_session(group_leader))
1030 goto out;
1031 }
1032
1033 err = security_task_setpgid(p, pgid);
1034 if (err)
1035 goto out;
1036
1037 if (task_pgrp(p) != pgrp)
1038 change_pid(p, PIDTYPE_PGID, pgrp);
1039
1040 err = 0;
1041 out:
1042 /* All paths lead to here, thus we are safe. -DaveM */
1043 write_unlock_irq(&tasklist_lock);
1044 rcu_read_unlock();
1045 return err;
1046 }
1047
1048 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1049 {
1050 struct task_struct *p;
1051 struct pid *grp;
1052 int retval;
1053
1054 rcu_read_lock();
1055 if (!pid)
1056 grp = task_pgrp(current);
1057 else {
1058 retval = -ESRCH;
1059 p = find_task_by_vpid(pid);
1060 if (!p)
1061 goto out;
1062 grp = task_pgrp(p);
1063 if (!grp)
1064 goto out;
1065
1066 retval = security_task_getpgid(p);
1067 if (retval)
1068 goto out;
1069 }
1070 retval = pid_vnr(grp);
1071 out:
1072 rcu_read_unlock();
1073 return retval;
1074 }
1075
1076 #ifdef __ARCH_WANT_SYS_GETPGRP
1077
1078 SYSCALL_DEFINE0(getpgrp)
1079 {
1080 return sys_getpgid(0);
1081 }
1082
1083 #endif
1084
1085 SYSCALL_DEFINE1(getsid, pid_t, pid)
1086 {
1087 struct task_struct *p;
1088 struct pid *sid;
1089 int retval;
1090
1091 rcu_read_lock();
1092 if (!pid)
1093 sid = task_session(current);
1094 else {
1095 retval = -ESRCH;
1096 p = find_task_by_vpid(pid);
1097 if (!p)
1098 goto out;
1099 sid = task_session(p);
1100 if (!sid)
1101 goto out;
1102
1103 retval = security_task_getsid(p);
1104 if (retval)
1105 goto out;
1106 }
1107 retval = pid_vnr(sid);
1108 out:
1109 rcu_read_unlock();
1110 return retval;
1111 }
1112
1113 SYSCALL_DEFINE0(setsid)
1114 {
1115 struct task_struct *group_leader = current->group_leader;
1116 struct pid *sid = task_pid(group_leader);
1117 pid_t session = pid_vnr(sid);
1118 int err = -EPERM;
1119
1120 write_lock_irq(&tasklist_lock);
1121 /* Fail if I am already a session leader */
1122 if (group_leader->signal->leader)
1123 goto out;
1124
1125 /* Fail if a process group id already exists that equals the
1126 * proposed session id.
1127 */
1128 if (pid_task(sid, PIDTYPE_PGID))
1129 goto out;
1130
1131 group_leader->signal->leader = 1;
1132 __set_special_pids(sid);
1133
1134 proc_clear_tty(group_leader);
1135
1136 err = session;
1137 out:
1138 write_unlock_irq(&tasklist_lock);
1139 if (err > 0) {
1140 proc_sid_connector(group_leader);
1141 sched_autogroup_create_attach(group_leader);
1142 }
1143 return err;
1144 }
1145
1146 DECLARE_RWSEM(uts_sem);
1147
1148 #ifdef COMPAT_UTS_MACHINE
1149 #define override_architecture(name) \
1150 (personality(current->personality) == PER_LINUX32 && \
1151 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1152 sizeof(COMPAT_UTS_MACHINE)))
1153 #else
1154 #define override_architecture(name) 0
1155 #endif
1156
1157 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1158 {
1159 int errno = 0;
1160
1161 down_read(&uts_sem);
1162 if (copy_to_user(name, utsname(), sizeof *name))
1163 errno = -EFAULT;
1164 up_read(&uts_sem);
1165
1166 if (!errno && override_architecture(name))
1167 errno = -EFAULT;
1168 return errno;
1169 }
1170
1171 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1172 /*
1173 * Old cruft
1174 */
1175 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1176 {
1177 int error = 0;
1178
1179 if (!name)
1180 return -EFAULT;
1181
1182 down_read(&uts_sem);
1183 if (copy_to_user(name, utsname(), sizeof(*name)))
1184 error = -EFAULT;
1185 up_read(&uts_sem);
1186
1187 if (!error && override_architecture(name))
1188 error = -EFAULT;
1189 return error;
1190 }
1191
1192 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1193 {
1194 int error;
1195
1196 if (!name)
1197 return -EFAULT;
1198 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1199 return -EFAULT;
1200
1201 down_read(&uts_sem);
1202 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1203 __OLD_UTS_LEN);
1204 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1205 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1206 __OLD_UTS_LEN);
1207 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1208 error |= __copy_to_user(&name->release, &utsname()->release,
1209 __OLD_UTS_LEN);
1210 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1211 error |= __copy_to_user(&name->version, &utsname()->version,
1212 __OLD_UTS_LEN);
1213 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1214 error |= __copy_to_user(&name->machine, &utsname()->machine,
1215 __OLD_UTS_LEN);
1216 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1217 up_read(&uts_sem);
1218
1219 if (!error && override_architecture(name))
1220 error = -EFAULT;
1221 return error ? -EFAULT : 0;
1222 }
1223 #endif
1224
1225 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1226 {
1227 int errno;
1228 char tmp[__NEW_UTS_LEN];
1229
1230 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1231 return -EPERM;
1232
1233 if (len < 0 || len > __NEW_UTS_LEN)
1234 return -EINVAL;
1235 down_write(&uts_sem);
1236 errno = -EFAULT;
1237 if (!copy_from_user(tmp, name, len)) {
1238 struct new_utsname *u = utsname();
1239
1240 memcpy(u->nodename, tmp, len);
1241 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1242 errno = 0;
1243 }
1244 up_write(&uts_sem);
1245 return errno;
1246 }
1247
1248 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1249
1250 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1251 {
1252 int i, errno;
1253 struct new_utsname *u;
1254
1255 if (len < 0)
1256 return -EINVAL;
1257 down_read(&uts_sem);
1258 u = utsname();
1259 i = 1 + strlen(u->nodename);
1260 if (i > len)
1261 i = len;
1262 errno = 0;
1263 if (copy_to_user(name, u->nodename, i))
1264 errno = -EFAULT;
1265 up_read(&uts_sem);
1266 return errno;
1267 }
1268
1269 #endif
1270
1271 /*
1272 * Only setdomainname; getdomainname can be implemented by calling
1273 * uname()
1274 */
1275 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1276 {
1277 int errno;
1278 char tmp[__NEW_UTS_LEN];
1279
1280 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1281 return -EPERM;
1282 if (len < 0 || len > __NEW_UTS_LEN)
1283 return -EINVAL;
1284
1285 down_write(&uts_sem);
1286 errno = -EFAULT;
1287 if (!copy_from_user(tmp, name, len)) {
1288 struct new_utsname *u = utsname();
1289
1290 memcpy(u->domainname, tmp, len);
1291 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1292 errno = 0;
1293 }
1294 up_write(&uts_sem);
1295 return errno;
1296 }
1297
1298 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1299 {
1300 struct rlimit value;
1301 int ret;
1302
1303 ret = do_prlimit(current, resource, NULL, &value);
1304 if (!ret)
1305 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1306
1307 return ret;
1308 }
1309
1310 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1311
1312 /*
1313 * Back compatibility for getrlimit. Needed for some apps.
1314 */
1315
1316 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1317 struct rlimit __user *, rlim)
1318 {
1319 struct rlimit x;
1320 if (resource >= RLIM_NLIMITS)
1321 return -EINVAL;
1322
1323 task_lock(current->group_leader);
1324 x = current->signal->rlim[resource];
1325 task_unlock(current->group_leader);
1326 if (x.rlim_cur > 0x7FFFFFFF)
1327 x.rlim_cur = 0x7FFFFFFF;
1328 if (x.rlim_max > 0x7FFFFFFF)
1329 x.rlim_max = 0x7FFFFFFF;
1330 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1331 }
1332
1333 #endif
1334
1335 static inline bool rlim64_is_infinity(__u64 rlim64)
1336 {
1337 #if BITS_PER_LONG < 64
1338 return rlim64 >= ULONG_MAX;
1339 #else
1340 return rlim64 == RLIM64_INFINITY;
1341 #endif
1342 }
1343
1344 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1345 {
1346 if (rlim->rlim_cur == RLIM_INFINITY)
1347 rlim64->rlim_cur = RLIM64_INFINITY;
1348 else
1349 rlim64->rlim_cur = rlim->rlim_cur;
1350 if (rlim->rlim_max == RLIM_INFINITY)
1351 rlim64->rlim_max = RLIM64_INFINITY;
1352 else
1353 rlim64->rlim_max = rlim->rlim_max;
1354 }
1355
1356 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1357 {
1358 if (rlim64_is_infinity(rlim64->rlim_cur))
1359 rlim->rlim_cur = RLIM_INFINITY;
1360 else
1361 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1362 if (rlim64_is_infinity(rlim64->rlim_max))
1363 rlim->rlim_max = RLIM_INFINITY;
1364 else
1365 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1366 }
1367
1368 /* make sure you are allowed to change @tsk limits before calling this */
1369 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1370 struct rlimit *new_rlim, struct rlimit *old_rlim)
1371 {
1372 struct rlimit *rlim;
1373 int retval = 0;
1374
1375 if (resource >= RLIM_NLIMITS)
1376 return -EINVAL;
1377 if (new_rlim) {
1378 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1379 return -EINVAL;
1380 if (resource == RLIMIT_NOFILE &&
1381 new_rlim->rlim_max > sysctl_nr_open)
1382 return -EPERM;
1383 }
1384
1385 /* protect tsk->signal and tsk->sighand from disappearing */
1386 read_lock(&tasklist_lock);
1387 if (!tsk->sighand) {
1388 retval = -ESRCH;
1389 goto out;
1390 }
1391
1392 rlim = tsk->signal->rlim + resource;
1393 task_lock(tsk->group_leader);
1394 if (new_rlim) {
1395 /* Keep the capable check against init_user_ns until
1396 cgroups can contain all limits */
1397 if (new_rlim->rlim_max > rlim->rlim_max &&
1398 !capable(CAP_SYS_RESOURCE))
1399 retval = -EPERM;
1400 if (!retval)
1401 retval = security_task_setrlimit(tsk->group_leader,
1402 resource, new_rlim);
1403 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1404 /*
1405 * The caller is asking for an immediate RLIMIT_CPU
1406 * expiry. But we use the zero value to mean "it was
1407 * never set". So let's cheat and make it one second
1408 * instead
1409 */
1410 new_rlim->rlim_cur = 1;
1411 }
1412 }
1413 if (!retval) {
1414 if (old_rlim)
1415 *old_rlim = *rlim;
1416 if (new_rlim)
1417 *rlim = *new_rlim;
1418 }
1419 task_unlock(tsk->group_leader);
1420
1421 /*
1422 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1423 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1424 * very long-standing error, and fixing it now risks breakage of
1425 * applications, so we live with it
1426 */
1427 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1428 new_rlim->rlim_cur != RLIM_INFINITY)
1429 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1430 out:
1431 read_unlock(&tasklist_lock);
1432 return retval;
1433 }
1434
1435 /* rcu lock must be held */
1436 static int check_prlimit_permission(struct task_struct *task)
1437 {
1438 const struct cred *cred = current_cred(), *tcred;
1439
1440 if (current == task)
1441 return 0;
1442
1443 tcred = __task_cred(task);
1444 if (cred->user->user_ns == tcred->user->user_ns &&
1445 (cred->uid == tcred->euid &&
1446 cred->uid == tcred->suid &&
1447 cred->uid == tcred->uid &&
1448 cred->gid == tcred->egid &&
1449 cred->gid == tcred->sgid &&
1450 cred->gid == tcred->gid))
1451 return 0;
1452 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1453 return 0;
1454
1455 return -EPERM;
1456 }
1457
1458 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1459 const struct rlimit64 __user *, new_rlim,
1460 struct rlimit64 __user *, old_rlim)
1461 {
1462 struct rlimit64 old64, new64;
1463 struct rlimit old, new;
1464 struct task_struct *tsk;
1465 int ret;
1466
1467 if (new_rlim) {
1468 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1469 return -EFAULT;
1470 rlim64_to_rlim(&new64, &new);
1471 }
1472
1473 rcu_read_lock();
1474 tsk = pid ? find_task_by_vpid(pid) : current;
1475 if (!tsk) {
1476 rcu_read_unlock();
1477 return -ESRCH;
1478 }
1479 ret = check_prlimit_permission(tsk);
1480 if (ret) {
1481 rcu_read_unlock();
1482 return ret;
1483 }
1484 get_task_struct(tsk);
1485 rcu_read_unlock();
1486
1487 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1488 old_rlim ? &old : NULL);
1489
1490 if (!ret && old_rlim) {
1491 rlim_to_rlim64(&old, &old64);
1492 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1493 ret = -EFAULT;
1494 }
1495
1496 put_task_struct(tsk);
1497 return ret;
1498 }
1499
1500 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1501 {
1502 struct rlimit new_rlim;
1503
1504 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1505 return -EFAULT;
1506 return do_prlimit(current, resource, &new_rlim, NULL);
1507 }
1508
1509 /*
1510 * It would make sense to put struct rusage in the task_struct,
1511 * except that would make the task_struct be *really big*. After
1512 * task_struct gets moved into malloc'ed memory, it would
1513 * make sense to do this. It will make moving the rest of the information
1514 * a lot simpler! (Which we're not doing right now because we're not
1515 * measuring them yet).
1516 *
1517 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1518 * races with threads incrementing their own counters. But since word
1519 * reads are atomic, we either get new values or old values and we don't
1520 * care which for the sums. We always take the siglock to protect reading
1521 * the c* fields from p->signal from races with exit.c updating those
1522 * fields when reaping, so a sample either gets all the additions of a
1523 * given child after it's reaped, or none so this sample is before reaping.
1524 *
1525 * Locking:
1526 * We need to take the siglock for CHILDEREN, SELF and BOTH
1527 * for the cases current multithreaded, non-current single threaded
1528 * non-current multithreaded. Thread traversal is now safe with
1529 * the siglock held.
1530 * Strictly speaking, we donot need to take the siglock if we are current and
1531 * single threaded, as no one else can take our signal_struct away, no one
1532 * else can reap the children to update signal->c* counters, and no one else
1533 * can race with the signal-> fields. If we do not take any lock, the
1534 * signal-> fields could be read out of order while another thread was just
1535 * exiting. So we should place a read memory barrier when we avoid the lock.
1536 * On the writer side, write memory barrier is implied in __exit_signal
1537 * as __exit_signal releases the siglock spinlock after updating the signal->
1538 * fields. But we don't do this yet to keep things simple.
1539 *
1540 */
1541
1542 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1543 {
1544 r->ru_nvcsw += t->nvcsw;
1545 r->ru_nivcsw += t->nivcsw;
1546 r->ru_minflt += t->min_flt;
1547 r->ru_majflt += t->maj_flt;
1548 r->ru_inblock += task_io_get_inblock(t);
1549 r->ru_oublock += task_io_get_oublock(t);
1550 }
1551
1552 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1553 {
1554 struct task_struct *t;
1555 unsigned long flags;
1556 cputime_t tgutime, tgstime, utime, stime;
1557 unsigned long maxrss = 0;
1558
1559 memset((char *) r, 0, sizeof *r);
1560 utime = stime = cputime_zero;
1561
1562 if (who == RUSAGE_THREAD) {
1563 task_times(current, &utime, &stime);
1564 accumulate_thread_rusage(p, r);
1565 maxrss = p->signal->maxrss;
1566 goto out;
1567 }
1568
1569 if (!lock_task_sighand(p, &flags))
1570 return;
1571
1572 switch (who) {
1573 case RUSAGE_BOTH:
1574 case RUSAGE_CHILDREN:
1575 utime = p->signal->cutime;
1576 stime = p->signal->cstime;
1577 r->ru_nvcsw = p->signal->cnvcsw;
1578 r->ru_nivcsw = p->signal->cnivcsw;
1579 r->ru_minflt = p->signal->cmin_flt;
1580 r->ru_majflt = p->signal->cmaj_flt;
1581 r->ru_inblock = p->signal->cinblock;
1582 r->ru_oublock = p->signal->coublock;
1583 maxrss = p->signal->cmaxrss;
1584
1585 if (who == RUSAGE_CHILDREN)
1586 break;
1587
1588 case RUSAGE_SELF:
1589 thread_group_times(p, &tgutime, &tgstime);
1590 utime = cputime_add(utime, tgutime);
1591 stime = cputime_add(stime, tgstime);
1592 r->ru_nvcsw += p->signal->nvcsw;
1593 r->ru_nivcsw += p->signal->nivcsw;
1594 r->ru_minflt += p->signal->min_flt;
1595 r->ru_majflt += p->signal->maj_flt;
1596 r->ru_inblock += p->signal->inblock;
1597 r->ru_oublock += p->signal->oublock;
1598 if (maxrss < p->signal->maxrss)
1599 maxrss = p->signal->maxrss;
1600 t = p;
1601 do {
1602 accumulate_thread_rusage(t, r);
1603 t = next_thread(t);
1604 } while (t != p);
1605 break;
1606
1607 default:
1608 BUG();
1609 }
1610 unlock_task_sighand(p, &flags);
1611
1612 out:
1613 cputime_to_timeval(utime, &r->ru_utime);
1614 cputime_to_timeval(stime, &r->ru_stime);
1615
1616 if (who != RUSAGE_CHILDREN) {
1617 struct mm_struct *mm = get_task_mm(p);
1618 if (mm) {
1619 setmax_mm_hiwater_rss(&maxrss, mm);
1620 mmput(mm);
1621 }
1622 }
1623 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1624 }
1625
1626 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1627 {
1628 struct rusage r;
1629 k_getrusage(p, who, &r);
1630 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1631 }
1632
1633 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1634 {
1635 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1636 who != RUSAGE_THREAD)
1637 return -EINVAL;
1638 return getrusage(current, who, ru);
1639 }
1640
1641 SYSCALL_DEFINE1(umask, int, mask)
1642 {
1643 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1644 return mask;
1645 }
1646
1647 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1648 unsigned long, arg4, unsigned long, arg5)
1649 {
1650 struct task_struct *me = current;
1651 unsigned char comm[sizeof(me->comm)];
1652 long error;
1653
1654 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1655 if (error != -ENOSYS)
1656 return error;
1657
1658 error = 0;
1659 switch (option) {
1660 case PR_SET_PDEATHSIG:
1661 if (!valid_signal(arg2)) {
1662 error = -EINVAL;
1663 break;
1664 }
1665 me->pdeath_signal = arg2;
1666 error = 0;
1667 break;
1668 case PR_GET_PDEATHSIG:
1669 error = put_user(me->pdeath_signal, (int __user *)arg2);
1670 break;
1671 case PR_GET_DUMPABLE:
1672 error = get_dumpable(me->mm);
1673 break;
1674 case PR_SET_DUMPABLE:
1675 if (arg2 < 0 || arg2 > 1) {
1676 error = -EINVAL;
1677 break;
1678 }
1679 set_dumpable(me->mm, arg2);
1680 error = 0;
1681 break;
1682
1683 case PR_SET_UNALIGN:
1684 error = SET_UNALIGN_CTL(me, arg2);
1685 break;
1686 case PR_GET_UNALIGN:
1687 error = GET_UNALIGN_CTL(me, arg2);
1688 break;
1689 case PR_SET_FPEMU:
1690 error = SET_FPEMU_CTL(me, arg2);
1691 break;
1692 case PR_GET_FPEMU:
1693 error = GET_FPEMU_CTL(me, arg2);
1694 break;
1695 case PR_SET_FPEXC:
1696 error = SET_FPEXC_CTL(me, arg2);
1697 break;
1698 case PR_GET_FPEXC:
1699 error = GET_FPEXC_CTL(me, arg2);
1700 break;
1701 case PR_GET_TIMING:
1702 error = PR_TIMING_STATISTICAL;
1703 break;
1704 case PR_SET_TIMING:
1705 if (arg2 != PR_TIMING_STATISTICAL)
1706 error = -EINVAL;
1707 else
1708 error = 0;
1709 break;
1710
1711 case PR_SET_NAME:
1712 comm[sizeof(me->comm)-1] = 0;
1713 if (strncpy_from_user(comm, (char __user *)arg2,
1714 sizeof(me->comm) - 1) < 0)
1715 return -EFAULT;
1716 set_task_comm(me, comm);
1717 return 0;
1718 case PR_GET_NAME:
1719 get_task_comm(comm, me);
1720 if (copy_to_user((char __user *)arg2, comm,
1721 sizeof(comm)))
1722 return -EFAULT;
1723 return 0;
1724 case PR_GET_ENDIAN:
1725 error = GET_ENDIAN(me, arg2);
1726 break;
1727 case PR_SET_ENDIAN:
1728 error = SET_ENDIAN(me, arg2);
1729 break;
1730
1731 case PR_GET_SECCOMP:
1732 error = prctl_get_seccomp();
1733 break;
1734 case PR_SET_SECCOMP:
1735 error = prctl_set_seccomp(arg2);
1736 break;
1737 case PR_GET_TSC:
1738 error = GET_TSC_CTL(arg2);
1739 break;
1740 case PR_SET_TSC:
1741 error = SET_TSC_CTL(arg2);
1742 break;
1743 case PR_TASK_PERF_EVENTS_DISABLE:
1744 error = perf_event_task_disable();
1745 break;
1746 case PR_TASK_PERF_EVENTS_ENABLE:
1747 error = perf_event_task_enable();
1748 break;
1749 case PR_GET_TIMERSLACK:
1750 error = current->timer_slack_ns;
1751 break;
1752 case PR_SET_TIMERSLACK:
1753 if (arg2 <= 0)
1754 current->timer_slack_ns =
1755 current->default_timer_slack_ns;
1756 else
1757 current->timer_slack_ns = arg2;
1758 error = 0;
1759 break;
1760 case PR_MCE_KILL:
1761 if (arg4 | arg5)
1762 return -EINVAL;
1763 switch (arg2) {
1764 case PR_MCE_KILL_CLEAR:
1765 if (arg3 != 0)
1766 return -EINVAL;
1767 current->flags &= ~PF_MCE_PROCESS;
1768 break;
1769 case PR_MCE_KILL_SET:
1770 current->flags |= PF_MCE_PROCESS;
1771 if (arg3 == PR_MCE_KILL_EARLY)
1772 current->flags |= PF_MCE_EARLY;
1773 else if (arg3 == PR_MCE_KILL_LATE)
1774 current->flags &= ~PF_MCE_EARLY;
1775 else if (arg3 == PR_MCE_KILL_DEFAULT)
1776 current->flags &=
1777 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1778 else
1779 return -EINVAL;
1780 break;
1781 default:
1782 return -EINVAL;
1783 }
1784 error = 0;
1785 break;
1786 case PR_MCE_KILL_GET:
1787 if (arg2 | arg3 | arg4 | arg5)
1788 return -EINVAL;
1789 if (current->flags & PF_MCE_PROCESS)
1790 error = (current->flags & PF_MCE_EARLY) ?
1791 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1792 else
1793 error = PR_MCE_KILL_DEFAULT;
1794 break;
1795 default:
1796 error = -EINVAL;
1797 break;
1798 }
1799 return error;
1800 }
1801
1802 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1803 struct getcpu_cache __user *, unused)
1804 {
1805 int err = 0;
1806 int cpu = raw_smp_processor_id();
1807 if (cpup)
1808 err |= put_user(cpu, cpup);
1809 if (nodep)
1810 err |= put_user(cpu_to_node(cpu), nodep);
1811 return err ? -EFAULT : 0;
1812 }
1813
1814 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1815
1816 static void argv_cleanup(struct subprocess_info *info)
1817 {
1818 argv_free(info->argv);
1819 }
1820
1821 /**
1822 * orderly_poweroff - Trigger an orderly system poweroff
1823 * @force: force poweroff if command execution fails
1824 *
1825 * This may be called from any context to trigger a system shutdown.
1826 * If the orderly shutdown fails, it will force an immediate shutdown.
1827 */
1828 int orderly_poweroff(bool force)
1829 {
1830 int argc;
1831 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1832 static char *envp[] = {
1833 "HOME=/",
1834 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1835 NULL
1836 };
1837 int ret = -ENOMEM;
1838 struct subprocess_info *info;
1839
1840 if (argv == NULL) {
1841 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1842 __func__, poweroff_cmd);
1843 goto out;
1844 }
1845
1846 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1847 if (info == NULL) {
1848 argv_free(argv);
1849 goto out;
1850 }
1851
1852 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1853
1854 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1855
1856 out:
1857 if (ret && force) {
1858 printk(KERN_WARNING "Failed to start orderly shutdown: "
1859 "forcing the issue\n");
1860
1861 /* I guess this should try to kick off some daemon to
1862 sync and poweroff asap. Or not even bother syncing
1863 if we're doing an emergency shutdown? */
1864 emergency_sync();
1865 kernel_power_off();
1866 }
1867
1868 return ret;
1869 }
1870 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linux kernel - Deliverables
This page took 0.067557 seconds and 5 git commands to generate.