blob: fc9ebbbaba0c4f16d4eceb34269e7b782988a125 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/config.h>
8#include <linux/module.h>
9#include <linux/mm.h>
10#include <linux/utsname.h>
11#include <linux/mman.h>
12#include <linux/smp_lock.h>
13#include <linux/notifier.h>
14#include <linux/reboot.h>
15#include <linux/prctl.h>
16#include <linux/init.h>
17#include <linux/highuid.h>
18#include <linux/fs.h>
Eric W. Biedermandc009d92005-06-25 14:57:52 -070019#include <linux/kernel.h>
20#include <linux/kexec.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/workqueue.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080022#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/device.h>
24#include <linux/key.h>
25#include <linux/times.h>
26#include <linux/posix-timers.h>
27#include <linux/security.h>
28#include <linux/dcookies.h>
29#include <linux/suspend.h>
30#include <linux/tty.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070031#include <linux/signal.h>
Matt Helsley9f460802005-11-07 00:59:16 -080032#include <linux/cn_proc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#include <linux/compat.h>
35#include <linux/syscalls.h>
Keshavamurthy Anil S00d7c052005-12-12 00:37:33 -080036#include <linux/kprobes.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38#include <asm/uaccess.h>
39#include <asm/io.h>
40#include <asm/unistd.h>
41
42#ifndef SET_UNALIGN_CTL
43# define SET_UNALIGN_CTL(a,b) (-EINVAL)
44#endif
45#ifndef GET_UNALIGN_CTL
46# define GET_UNALIGN_CTL(a,b) (-EINVAL)
47#endif
48#ifndef SET_FPEMU_CTL
49# define SET_FPEMU_CTL(a,b) (-EINVAL)
50#endif
51#ifndef GET_FPEMU_CTL
52# define GET_FPEMU_CTL(a,b) (-EINVAL)
53#endif
54#ifndef SET_FPEXC_CTL
55# define SET_FPEXC_CTL(a,b) (-EINVAL)
56#endif
57#ifndef GET_FPEXC_CTL
58# define GET_FPEXC_CTL(a,b) (-EINVAL)
59#endif
60
61/*
62 * this is where the system-wide overflow UID and GID are defined, for
63 * architectures that now have 32-bit UID/GID but didn't in the past
64 */
65
66int overflowuid = DEFAULT_OVERFLOWUID;
67int overflowgid = DEFAULT_OVERFLOWGID;
68
69#ifdef CONFIG_UID16
70EXPORT_SYMBOL(overflowuid);
71EXPORT_SYMBOL(overflowgid);
72#endif
73
74/*
75 * the same as above, but for filesystems which can only store a 16-bit
76 * UID and GID. as such, this is needed on all architectures
77 */
78
79int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
80int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
81
82EXPORT_SYMBOL(fs_overflowuid);
83EXPORT_SYMBOL(fs_overflowgid);
84
85/*
86 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
87 */
88
89int C_A_D = 1;
90int cad_pid = 1;
91
92/*
93 * Notifier list for kernel code which wants to be called
94 * at shutdown. This is used to stop any idling DMA operations
95 * and the like.
96 */
97
Alan Sterne041c682006-03-27 01:16:30 -080098static BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
Alan Sterne041c682006-03-27 01:16:30 -0800100/*
101 * Notifier chain core routines. The exported routines below
102 * are layered on top of these, with appropriate locking added.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 */
Alan Sterne041c682006-03-27 01:16:30 -0800104
105static int notifier_chain_register(struct notifier_block **nl,
106 struct notifier_block *n)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
Alan Sterne041c682006-03-27 01:16:30 -0800108 while ((*nl) != NULL) {
109 if (n->priority > (*nl)->priority)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 break;
Alan Sterne041c682006-03-27 01:16:30 -0800111 nl = &((*nl)->next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 }
Alan Sterne041c682006-03-27 01:16:30 -0800113 n->next = *nl;
114 rcu_assign_pointer(*nl, n);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 return 0;
116}
117
Alan Sterne041c682006-03-27 01:16:30 -0800118static int notifier_chain_unregister(struct notifier_block **nl,
119 struct notifier_block *n)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
Alan Sterne041c682006-03-27 01:16:30 -0800121 while ((*nl) != NULL) {
122 if ((*nl) == n) {
123 rcu_assign_pointer(*nl, n->next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 return 0;
125 }
Alan Sterne041c682006-03-27 01:16:30 -0800126 nl = &((*nl)->next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 return -ENOENT;
129}
130
Alan Sterne041c682006-03-27 01:16:30 -0800131static int __kprobes notifier_call_chain(struct notifier_block **nl,
132 unsigned long val, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133{
Alan Sterne041c682006-03-27 01:16:30 -0800134 int ret = NOTIFY_DONE;
135 struct notifier_block *nb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Alan Sterne041c682006-03-27 01:16:30 -0800137 nb = rcu_dereference(*nl);
138 while (nb) {
139 ret = nb->notifier_call(nb, val, v);
140 if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK)
141 break;
142 nb = rcu_dereference(nb->next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 }
144 return ret;
145}
146
Alan Sterne041c682006-03-27 01:16:30 -0800147/*
148 * Atomic notifier chain routines. Registration and unregistration
149 * use a mutex, and call_chain is synchronized by RCU (no locks).
150 */
151
152/**
153 * atomic_notifier_chain_register - Add notifier to an atomic notifier chain
154 * @nh: Pointer to head of the atomic notifier chain
155 * @n: New entry in notifier chain
156 *
157 * Adds a notifier to an atomic notifier chain.
158 *
159 * Currently always returns zero.
160 */
161
162int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
163 struct notifier_block *n)
164{
165 unsigned long flags;
166 int ret;
167
168 spin_lock_irqsave(&nh->lock, flags);
169 ret = notifier_chain_register(&nh->head, n);
170 spin_unlock_irqrestore(&nh->lock, flags);
171 return ret;
172}
173
174EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
175
176/**
177 * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
178 * @nh: Pointer to head of the atomic notifier chain
179 * @n: Entry to remove from notifier chain
180 *
181 * Removes a notifier from an atomic notifier chain.
182 *
183 * Returns zero on success or %-ENOENT on failure.
184 */
185int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
186 struct notifier_block *n)
187{
188 unsigned long flags;
189 int ret;
190
191 spin_lock_irqsave(&nh->lock, flags);
192 ret = notifier_chain_unregister(&nh->head, n);
193 spin_unlock_irqrestore(&nh->lock, flags);
194 synchronize_rcu();
195 return ret;
196}
197
198EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
199
200/**
201 * atomic_notifier_call_chain - Call functions in an atomic notifier chain
202 * @nh: Pointer to head of the atomic notifier chain
203 * @val: Value passed unmodified to notifier function
204 * @v: Pointer passed unmodified to notifier function
205 *
206 * Calls each function in a notifier chain in turn. The functions
207 * run in an atomic context, so they must not block.
208 * This routine uses RCU to synchronize with changes to the chain.
209 *
210 * If the return value of the notifier can be and'ed
211 * with %NOTIFY_STOP_MASK then atomic_notifier_call_chain
212 * will return immediately, with the return value of
213 * the notifier function which halted execution.
214 * Otherwise the return value is the return value
215 * of the last notifier function called.
216 */
217
218int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
219 unsigned long val, void *v)
220{
221 int ret;
222
223 rcu_read_lock();
224 ret = notifier_call_chain(&nh->head, val, v);
225 rcu_read_unlock();
226 return ret;
227}
228
229EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
230
231/*
232 * Blocking notifier chain routines. All access to the chain is
233 * synchronized by an rwsem.
234 */
235
236/**
237 * blocking_notifier_chain_register - Add notifier to a blocking notifier chain
238 * @nh: Pointer to head of the blocking notifier chain
239 * @n: New entry in notifier chain
240 *
241 * Adds a notifier to a blocking notifier chain.
242 * Must be called in process context.
243 *
244 * Currently always returns zero.
245 */
246
247int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
248 struct notifier_block *n)
249{
250 int ret;
251
252 /*
253 * This code gets used during boot-up, when task switching is
254 * not yet working and interrupts must remain disabled. At
255 * such times we must not call down_write().
256 */
257 if (unlikely(system_state == SYSTEM_BOOTING))
258 return notifier_chain_register(&nh->head, n);
259
260 down_write(&nh->rwsem);
261 ret = notifier_chain_register(&nh->head, n);
262 up_write(&nh->rwsem);
263 return ret;
264}
265
266EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
267
268/**
269 * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
270 * @nh: Pointer to head of the blocking notifier chain
271 * @n: Entry to remove from notifier chain
272 *
273 * Removes a notifier from a blocking notifier chain.
274 * Must be called from process context.
275 *
276 * Returns zero on success or %-ENOENT on failure.
277 */
278int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
279 struct notifier_block *n)
280{
281 int ret;
282
283 /*
284 * This code gets used during boot-up, when task switching is
285 * not yet working and interrupts must remain disabled. At
286 * such times we must not call down_write().
287 */
288 if (unlikely(system_state == SYSTEM_BOOTING))
289 return notifier_chain_unregister(&nh->head, n);
290
291 down_write(&nh->rwsem);
292 ret = notifier_chain_unregister(&nh->head, n);
293 up_write(&nh->rwsem);
294 return ret;
295}
296
297EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
298
299/**
300 * blocking_notifier_call_chain - Call functions in a blocking notifier chain
301 * @nh: Pointer to head of the blocking notifier chain
302 * @val: Value passed unmodified to notifier function
303 * @v: Pointer passed unmodified to notifier function
304 *
305 * Calls each function in a notifier chain in turn. The functions
306 * run in a process context, so they are allowed to block.
307 *
308 * If the return value of the notifier can be and'ed
309 * with %NOTIFY_STOP_MASK then blocking_notifier_call_chain
310 * will return immediately, with the return value of
311 * the notifier function which halted execution.
312 * Otherwise the return value is the return value
313 * of the last notifier function called.
314 */
315
316int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
317 unsigned long val, void *v)
318{
319 int ret;
320
321 down_read(&nh->rwsem);
322 ret = notifier_call_chain(&nh->head, val, v);
323 up_read(&nh->rwsem);
324 return ret;
325}
326
327EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
328
329/*
330 * Raw notifier chain routines. There is no protection;
331 * the caller must provide it. Use at your own risk!
332 */
333
334/**
335 * raw_notifier_chain_register - Add notifier to a raw notifier chain
336 * @nh: Pointer to head of the raw notifier chain
337 * @n: New entry in notifier chain
338 *
339 * Adds a notifier to a raw notifier chain.
340 * All locking must be provided by the caller.
341 *
342 * Currently always returns zero.
343 */
344
345int raw_notifier_chain_register(struct raw_notifier_head *nh,
346 struct notifier_block *n)
347{
348 return notifier_chain_register(&nh->head, n);
349}
350
351EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
352
353/**
354 * raw_notifier_chain_unregister - Remove notifier from a raw notifier chain
355 * @nh: Pointer to head of the raw notifier chain
356 * @n: Entry to remove from notifier chain
357 *
358 * Removes a notifier from a raw notifier chain.
359 * All locking must be provided by the caller.
360 *
361 * Returns zero on success or %-ENOENT on failure.
362 */
363int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
364 struct notifier_block *n)
365{
366 return notifier_chain_unregister(&nh->head, n);
367}
368
369EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
370
371/**
372 * raw_notifier_call_chain - Call functions in a raw notifier chain
373 * @nh: Pointer to head of the raw notifier chain
374 * @val: Value passed unmodified to notifier function
375 * @v: Pointer passed unmodified to notifier function
376 *
377 * Calls each function in a notifier chain in turn. The functions
378 * run in an undefined context.
379 * All locking must be provided by the caller.
380 *
381 * If the return value of the notifier can be and'ed
382 * with %NOTIFY_STOP_MASK then raw_notifier_call_chain
383 * will return immediately, with the return value of
384 * the notifier function which halted execution.
385 * Otherwise the return value is the return value
386 * of the last notifier function called.
387 */
388
389int raw_notifier_call_chain(struct raw_notifier_head *nh,
390 unsigned long val, void *v)
391{
392 return notifier_call_chain(&nh->head, val, v);
393}
394
395EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396
397/**
398 * register_reboot_notifier - Register function to be called at reboot time
399 * @nb: Info about notifier function to be called
400 *
401 * Registers a function with the list of functions
402 * to be called at reboot time.
403 *
Alan Sterne041c682006-03-27 01:16:30 -0800404 * Currently always returns zero, as blocking_notifier_chain_register
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 * always returns zero.
406 */
407
408int register_reboot_notifier(struct notifier_block * nb)
409{
Alan Sterne041c682006-03-27 01:16:30 -0800410 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411}
412
413EXPORT_SYMBOL(register_reboot_notifier);
414
415/**
416 * unregister_reboot_notifier - Unregister previously registered reboot notifier
417 * @nb: Hook to be unregistered
418 *
419 * Unregisters a previously registered reboot
420 * notifier function.
421 *
422 * Returns zero on success, or %-ENOENT on failure.
423 */
424
425int unregister_reboot_notifier(struct notifier_block * nb)
426{
Alan Sterne041c682006-03-27 01:16:30 -0800427 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428}
429
430EXPORT_SYMBOL(unregister_reboot_notifier);
431
432static int set_one_prio(struct task_struct *p, int niceval, int error)
433{
434 int no_nice;
435
436 if (p->uid != current->euid &&
437 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
438 error = -EPERM;
439 goto out;
440 }
Matt Mackalle43379f2005-05-01 08:59:00 -0700441 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 error = -EACCES;
443 goto out;
444 }
445 no_nice = security_task_setnice(p, niceval);
446 if (no_nice) {
447 error = no_nice;
448 goto out;
449 }
450 if (error == -ESRCH)
451 error = 0;
452 set_user_nice(p, niceval);
453out:
454 return error;
455}
456
457asmlinkage long sys_setpriority(int which, int who, int niceval)
458{
459 struct task_struct *g, *p;
460 struct user_struct *user;
461 int error = -EINVAL;
462
463 if (which > 2 || which < 0)
464 goto out;
465
466 /* normalize: avoid signed division (rounding problems) */
467 error = -ESRCH;
468 if (niceval < -20)
469 niceval = -20;
470 if (niceval > 19)
471 niceval = 19;
472
473 read_lock(&tasklist_lock);
474 switch (which) {
475 case PRIO_PROCESS:
476 if (!who)
477 who = current->pid;
478 p = find_task_by_pid(who);
479 if (p)
480 error = set_one_prio(p, niceval, error);
481 break;
482 case PRIO_PGRP:
483 if (!who)
484 who = process_group(current);
485 do_each_task_pid(who, PIDTYPE_PGID, p) {
486 error = set_one_prio(p, niceval, error);
487 } while_each_task_pid(who, PIDTYPE_PGID, p);
488 break;
489 case PRIO_USER:
490 user = current->user;
491 if (!who)
492 who = current->uid;
493 else
494 if ((who != current->uid) && !(user = find_user(who)))
495 goto out_unlock; /* No processes for this user */
496
497 do_each_thread(g, p)
498 if (p->uid == who)
499 error = set_one_prio(p, niceval, error);
500 while_each_thread(g, p);
501 if (who != current->uid)
502 free_uid(user); /* For find_user() */
503 break;
504 }
505out_unlock:
506 read_unlock(&tasklist_lock);
507out:
508 return error;
509}
510
511/*
512 * Ugh. To avoid negative return values, "getpriority()" will
513 * not return the normal nice-value, but a negated value that
514 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
515 * to stay compatible.
516 */
517asmlinkage long sys_getpriority(int which, int who)
518{
519 struct task_struct *g, *p;
520 struct user_struct *user;
521 long niceval, retval = -ESRCH;
522
523 if (which > 2 || which < 0)
524 return -EINVAL;
525
526 read_lock(&tasklist_lock);
527 switch (which) {
528 case PRIO_PROCESS:
529 if (!who)
530 who = current->pid;
531 p = find_task_by_pid(who);
532 if (p) {
533 niceval = 20 - task_nice(p);
534 if (niceval > retval)
535 retval = niceval;
536 }
537 break;
538 case PRIO_PGRP:
539 if (!who)
540 who = process_group(current);
541 do_each_task_pid(who, PIDTYPE_PGID, p) {
542 niceval = 20 - task_nice(p);
543 if (niceval > retval)
544 retval = niceval;
545 } while_each_task_pid(who, PIDTYPE_PGID, p);
546 break;
547 case PRIO_USER:
548 user = current->user;
549 if (!who)
550 who = current->uid;
551 else
552 if ((who != current->uid) && !(user = find_user(who)))
553 goto out_unlock; /* No processes for this user */
554
555 do_each_thread(g, p)
556 if (p->uid == who) {
557 niceval = 20 - task_nice(p);
558 if (niceval > retval)
559 retval = niceval;
560 }
561 while_each_thread(g, p);
562 if (who != current->uid)
563 free_uid(user); /* for find_user() */
564 break;
565 }
566out_unlock:
567 read_unlock(&tasklist_lock);
568
569 return retval;
570}
571
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700572/**
573 * emergency_restart - reboot the system
574 *
575 * Without shutting down any hardware or taking any locks
576 * reboot the system. This is called when we know we are in
577 * trouble so this is our best effort to reboot. This is
578 * safe to call in interrupt context.
579 */
Eric W. Biederman7c903472005-07-26 11:29:55 -0600580void emergency_restart(void)
581{
582 machine_emergency_restart();
583}
584EXPORT_SYMBOL_GPL(emergency_restart);
585
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700586void kernel_restart_prepare(char *cmd)
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600587{
Alan Sterne041c682006-03-27 01:16:30 -0800588 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600589 system_state = SYSTEM_RESTART;
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600590 device_shutdown();
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700591}
Randy Dunlap1e5d5332005-11-07 01:01:06 -0800592
593/**
594 * kernel_restart - reboot the system
595 * @cmd: pointer to buffer containing command to execute for restart
Randy Dunlapb8887e62005-11-07 01:01:07 -0800596 * or %NULL
Randy Dunlap1e5d5332005-11-07 01:01:06 -0800597 *
598 * Shutdown everything and perform a clean reboot.
599 * This is not safe to call in interrupt context.
600 */
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700601void kernel_restart(char *cmd)
602{
603 kernel_restart_prepare(cmd);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600604 if (!cmd) {
605 printk(KERN_EMERG "Restarting system.\n");
606 } else {
607 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
608 }
609 printk(".\n");
610 machine_restart(cmd);
611}
612EXPORT_SYMBOL_GPL(kernel_restart);
613
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700614/**
615 * kernel_kexec - reboot the system
616 *
617 * Move into place and start executing a preloaded standalone
618 * executable. If nothing was preloaded return an error.
619 */
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600620void kernel_kexec(void)
621{
622#ifdef CONFIG_KEXEC
623 struct kimage *image;
Al Viro4bb80892006-02-01 05:57:32 -0500624 image = xchg(&kexec_image, NULL);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600625 if (!image) {
626 return;
627 }
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700628 kernel_restart_prepare(NULL);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600629 printk(KERN_EMERG "Starting new kernel\n");
630 machine_shutdown();
631 machine_kexec(image);
632#endif
633}
634EXPORT_SYMBOL_GPL(kernel_kexec);
635
Alexey Starikovskiy729b4d42005-12-01 04:29:00 -0500636void kernel_shutdown_prepare(enum system_states state)
637{
Alan Sterne041c682006-03-27 01:16:30 -0800638 blocking_notifier_call_chain(&reboot_notifier_list,
Alexey Starikovskiy729b4d42005-12-01 04:29:00 -0500639 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
640 system_state = state;
641 device_shutdown();
642}
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700643/**
644 * kernel_halt - halt the system
645 *
646 * Shutdown everything and perform a clean system halt.
647 */
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700648void kernel_halt(void)
649{
Alexey Starikovskiy729b4d42005-12-01 04:29:00 -0500650 kernel_shutdown_prepare(SYSTEM_HALT);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600651 printk(KERN_EMERG "System halted.\n");
652 machine_halt();
653}
Alexey Starikovskiy729b4d42005-12-01 04:29:00 -0500654
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600655EXPORT_SYMBOL_GPL(kernel_halt);
656
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700657/**
658 * kernel_power_off - power_off the system
659 *
660 * Shutdown everything and perform a clean system power_off.
661 */
Eric W. Biedermane4c94332005-09-22 21:43:45 -0700662void kernel_power_off(void)
663{
Alexey Starikovskiy729b4d42005-12-01 04:29:00 -0500664 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600665 printk(KERN_EMERG "Power down.\n");
666 machine_power_off();
667}
668EXPORT_SYMBOL_GPL(kernel_power_off);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669/*
670 * Reboot system call: for obvious reasons only root may call it,
671 * and even root needs to set up some magic numbers in the registers
672 * so that some mistake won't make this reboot the whole machine.
673 * You can also set the meaning of the ctrl-alt-del-key here.
674 *
675 * reboot doesn't sync: do that yourself before calling this.
676 */
677asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
678{
679 char buffer[256];
680
681 /* We only trust the superuser with rebooting the system. */
682 if (!capable(CAP_SYS_BOOT))
683 return -EPERM;
684
685 /* For safety, we require "magic" arguments. */
686 if (magic1 != LINUX_REBOOT_MAGIC1 ||
687 (magic2 != LINUX_REBOOT_MAGIC2 &&
688 magic2 != LINUX_REBOOT_MAGIC2A &&
689 magic2 != LINUX_REBOOT_MAGIC2B &&
690 magic2 != LINUX_REBOOT_MAGIC2C))
691 return -EINVAL;
692
Eric W. Biederman5e382912006-01-08 01:03:46 -0800693 /* Instead of trying to make the power_off code look like
694 * halt when pm_power_off is not set do it the easy way.
695 */
696 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
697 cmd = LINUX_REBOOT_CMD_HALT;
698
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 lock_kernel();
700 switch (cmd) {
701 case LINUX_REBOOT_CMD_RESTART:
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600702 kernel_restart(NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 break;
704
705 case LINUX_REBOOT_CMD_CAD_ON:
706 C_A_D = 1;
707 break;
708
709 case LINUX_REBOOT_CMD_CAD_OFF:
710 C_A_D = 0;
711 break;
712
713 case LINUX_REBOOT_CMD_HALT:
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600714 kernel_halt();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 unlock_kernel();
716 do_exit(0);
717 break;
718
719 case LINUX_REBOOT_CMD_POWER_OFF:
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600720 kernel_power_off();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 unlock_kernel();
722 do_exit(0);
723 break;
724
725 case LINUX_REBOOT_CMD_RESTART2:
726 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
727 unlock_kernel();
728 return -EFAULT;
729 }
730 buffer[sizeof(buffer) - 1] = '\0';
731
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600732 kernel_restart(buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 break;
734
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700735 case LINUX_REBOOT_CMD_KEXEC:
Eric W. Biederman4a00ea12005-07-26 11:24:14 -0600736 kernel_kexec();
737 unlock_kernel();
738 return -EINVAL;
739
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740#ifdef CONFIG_SOFTWARE_SUSPEND
741 case LINUX_REBOOT_CMD_SW_SUSPEND:
742 {
743 int ret = software_suspend();
744 unlock_kernel();
745 return ret;
746 }
747#endif
748
749 default:
750 unlock_kernel();
751 return -EINVAL;
752 }
753 unlock_kernel();
754 return 0;
755}
756
757static void deferred_cad(void *dummy)
758{
Eric W. Biedermanabcd9e52005-07-26 11:27:34 -0600759 kernel_restart(NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760}
761
762/*
763 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
764 * As it's called within an interrupt, it may NOT sync: the only choice
765 * is whether to reboot at once, or just ignore the ctrl-alt-del.
766 */
767void ctrl_alt_del(void)
768{
769 static DECLARE_WORK(cad_work, deferred_cad, NULL);
770
771 if (C_A_D)
772 schedule_work(&cad_work);
773 else
774 kill_proc(cad_pid, SIGINT, 1);
775}
776
777
778/*
779 * Unprivileged users may change the real gid to the effective gid
780 * or vice versa. (BSD-style)
781 *
782 * If you set the real gid at all, or set the effective gid to a value not
783 * equal to the real gid, then the saved gid is set to the new effective gid.
784 *
785 * This makes it possible for a setgid program to completely drop its
786 * privileges, which is often a useful assertion to make when you are doing
787 * a security audit over a program.
788 *
789 * The general idea is that a program which uses just setregid() will be
790 * 100% compatible with BSD. A program which uses just setgid() will be
791 * 100% compatible with POSIX with saved IDs.
792 *
793 * SMP: There are not races, the GIDs are checked only by filesystem
794 * operations (as far as semantic preservation is concerned).
795 */
796asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
797{
798 int old_rgid = current->gid;
799 int old_egid = current->egid;
800 int new_rgid = old_rgid;
801 int new_egid = old_egid;
802 int retval;
803
804 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
805 if (retval)
806 return retval;
807
808 if (rgid != (gid_t) -1) {
809 if ((old_rgid == rgid) ||
810 (current->egid==rgid) ||
811 capable(CAP_SETGID))
812 new_rgid = rgid;
813 else
814 return -EPERM;
815 }
816 if (egid != (gid_t) -1) {
817 if ((old_rgid == egid) ||
818 (current->egid == egid) ||
819 (current->sgid == egid) ||
820 capable(CAP_SETGID))
821 new_egid = egid;
822 else {
823 return -EPERM;
824 }
825 }
826 if (new_egid != old_egid)
827 {
Alan Coxd6e71142005-06-23 00:09:43 -0700828 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700829 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 }
831 if (rgid != (gid_t) -1 ||
832 (egid != (gid_t) -1 && egid != old_rgid))
833 current->sgid = new_egid;
834 current->fsgid = new_egid;
835 current->egid = new_egid;
836 current->gid = new_rgid;
837 key_fsgid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -0800838 proc_id_connector(current, PROC_EVENT_GID);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 return 0;
840}
841
842/*
843 * setgid() is implemented like SysV w/ SAVED_IDS
844 *
845 * SMP: Same implicit races as above.
846 */
847asmlinkage long sys_setgid(gid_t gid)
848{
849 int old_egid = current->egid;
850 int retval;
851
852 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
853 if (retval)
854 return retval;
855
856 if (capable(CAP_SETGID))
857 {
858 if(old_egid != gid)
859 {
Alan Coxd6e71142005-06-23 00:09:43 -0700860 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700861 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 }
863 current->gid = current->egid = current->sgid = current->fsgid = gid;
864 }
865 else if ((gid == current->gid) || (gid == current->sgid))
866 {
867 if(old_egid != gid)
868 {
Alan Coxd6e71142005-06-23 00:09:43 -0700869 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700870 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 }
872 current->egid = current->fsgid = gid;
873 }
874 else
875 return -EPERM;
876
877 key_fsgid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -0800878 proc_id_connector(current, PROC_EVENT_GID);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 return 0;
880}
881
882static int set_user(uid_t new_ruid, int dumpclear)
883{
884 struct user_struct *new_user;
885
886 new_user = alloc_uid(new_ruid);
887 if (!new_user)
888 return -EAGAIN;
889
890 if (atomic_read(&new_user->processes) >=
891 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
892 new_user != &root_user) {
893 free_uid(new_user);
894 return -EAGAIN;
895 }
896
897 switch_uid(new_user);
898
899 if(dumpclear)
900 {
Alan Coxd6e71142005-06-23 00:09:43 -0700901 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700902 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 }
904 current->uid = new_ruid;
905 return 0;
906}
907
908/*
909 * Unprivileged users may change the real uid to the effective uid
910 * or vice versa. (BSD-style)
911 *
912 * If you set the real uid at all, or set the effective uid to a value not
913 * equal to the real uid, then the saved uid is set to the new effective uid.
914 *
915 * This makes it possible for a setuid program to completely drop its
916 * privileges, which is often a useful assertion to make when you are doing
917 * a security audit over a program.
918 *
919 * The general idea is that a program which uses just setreuid() will be
920 * 100% compatible with BSD. A program which uses just setuid() will be
921 * 100% compatible with POSIX with saved IDs.
922 */
923asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
924{
925 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
926 int retval;
927
928 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
929 if (retval)
930 return retval;
931
932 new_ruid = old_ruid = current->uid;
933 new_euid = old_euid = current->euid;
934 old_suid = current->suid;
935
936 if (ruid != (uid_t) -1) {
937 new_ruid = ruid;
938 if ((old_ruid != ruid) &&
939 (current->euid != ruid) &&
940 !capable(CAP_SETUID))
941 return -EPERM;
942 }
943
944 if (euid != (uid_t) -1) {
945 new_euid = euid;
946 if ((old_ruid != euid) &&
947 (current->euid != euid) &&
948 (current->suid != euid) &&
949 !capable(CAP_SETUID))
950 return -EPERM;
951 }
952
953 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
954 return -EAGAIN;
955
956 if (new_euid != old_euid)
957 {
Alan Coxd6e71142005-06-23 00:09:43 -0700958 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700959 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 }
961 current->fsuid = current->euid = new_euid;
962 if (ruid != (uid_t) -1 ||
963 (euid != (uid_t) -1 && euid != old_ruid))
964 current->suid = current->euid;
965 current->fsuid = current->euid;
966
967 key_fsuid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -0800968 proc_id_connector(current, PROC_EVENT_UID);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
970 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
971}
972
973
974
975/*
976 * setuid() is implemented like SysV with SAVED_IDS
977 *
978 * Note that SAVED_ID's is deficient in that a setuid root program
979 * like sendmail, for example, cannot set its uid to be a normal
980 * user and then switch back, because if you're root, setuid() sets
981 * the saved uid too. If you don't like this, blame the bright people
982 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
983 * will allow a root program to temporarily drop privileges and be able to
984 * regain them by swapping the real and effective uid.
985 */
986asmlinkage long sys_setuid(uid_t uid)
987{
988 int old_euid = current->euid;
989 int old_ruid, old_suid, new_ruid, new_suid;
990 int retval;
991
992 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
993 if (retval)
994 return retval;
995
996 old_ruid = new_ruid = current->uid;
997 old_suid = current->suid;
998 new_suid = old_suid;
999
1000 if (capable(CAP_SETUID)) {
1001 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
1002 return -EAGAIN;
1003 new_suid = uid;
1004 } else if ((uid != current->uid) && (uid != new_suid))
1005 return -EPERM;
1006
1007 if (old_euid != uid)
1008 {
Alan Coxd6e71142005-06-23 00:09:43 -07001009 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -07001010 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 }
1012 current->fsuid = current->euid = uid;
1013 current->suid = new_suid;
1014
1015 key_fsuid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -08001016 proc_id_connector(current, PROC_EVENT_UID);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017
1018 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
1019}
1020
1021
1022/*
1023 * This function implements a generic ability to update ruid, euid,
1024 * and suid. This allows you to implement the 4.4 compatible seteuid().
1025 */
1026asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
1027{
1028 int old_ruid = current->uid;
1029 int old_euid = current->euid;
1030 int old_suid = current->suid;
1031 int retval;
1032
1033 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
1034 if (retval)
1035 return retval;
1036
1037 if (!capable(CAP_SETUID)) {
1038 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
1039 (ruid != current->euid) && (ruid != current->suid))
1040 return -EPERM;
1041 if ((euid != (uid_t) -1) && (euid != current->uid) &&
1042 (euid != current->euid) && (euid != current->suid))
1043 return -EPERM;
1044 if ((suid != (uid_t) -1) && (suid != current->uid) &&
1045 (suid != current->euid) && (suid != current->suid))
1046 return -EPERM;
1047 }
1048 if (ruid != (uid_t) -1) {
1049 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
1050 return -EAGAIN;
1051 }
1052 if (euid != (uid_t) -1) {
1053 if (euid != current->euid)
1054 {
Alan Coxd6e71142005-06-23 00:09:43 -07001055 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -07001056 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 }
1058 current->euid = euid;
1059 }
1060 current->fsuid = current->euid;
1061 if (suid != (uid_t) -1)
1062 current->suid = suid;
1063
1064 key_fsuid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -08001065 proc_id_connector(current, PROC_EVENT_UID);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066
1067 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
1068}
1069
1070asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
1071{
1072 int retval;
1073
1074 if (!(retval = put_user(current->uid, ruid)) &&
1075 !(retval = put_user(current->euid, euid)))
1076 retval = put_user(current->suid, suid);
1077
1078 return retval;
1079}
1080
1081/*
1082 * Same as above, but for rgid, egid, sgid.
1083 */
1084asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
1085{
1086 int retval;
1087
1088 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
1089 if (retval)
1090 return retval;
1091
1092 if (!capable(CAP_SETGID)) {
1093 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
1094 (rgid != current->egid) && (rgid != current->sgid))
1095 return -EPERM;
1096 if ((egid != (gid_t) -1) && (egid != current->gid) &&
1097 (egid != current->egid) && (egid != current->sgid))
1098 return -EPERM;
1099 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
1100 (sgid != current->egid) && (sgid != current->sgid))
1101 return -EPERM;
1102 }
1103 if (egid != (gid_t) -1) {
1104 if (egid != current->egid)
1105 {
Alan Coxd6e71142005-06-23 00:09:43 -07001106 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -07001107 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 }
1109 current->egid = egid;
1110 }
1111 current->fsgid = current->egid;
1112 if (rgid != (gid_t) -1)
1113 current->gid = rgid;
1114 if (sgid != (gid_t) -1)
1115 current->sgid = sgid;
1116
1117 key_fsgid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -08001118 proc_id_connector(current, PROC_EVENT_GID);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 return 0;
1120}
1121
1122asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
1123{
1124 int retval;
1125
1126 if (!(retval = put_user(current->gid, rgid)) &&
1127 !(retval = put_user(current->egid, egid)))
1128 retval = put_user(current->sgid, sgid);
1129
1130 return retval;
1131}
1132
1133
1134/*
1135 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
1136 * is used for "access()" and for the NFS daemon (letting nfsd stay at
1137 * whatever uid it wants to). It normally shadows "euid", except when
1138 * explicitly set by setfsuid() or for access..
1139 */
1140asmlinkage long sys_setfsuid(uid_t uid)
1141{
1142 int old_fsuid;
1143
1144 old_fsuid = current->fsuid;
1145 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
1146 return old_fsuid;
1147
1148 if (uid == current->uid || uid == current->euid ||
1149 uid == current->suid || uid == current->fsuid ||
1150 capable(CAP_SETUID))
1151 {
1152 if (uid != old_fsuid)
1153 {
Alan Coxd6e71142005-06-23 00:09:43 -07001154 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -07001155 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 }
1157 current->fsuid = uid;
1158 }
1159
1160 key_fsuid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -08001161 proc_id_connector(current, PROC_EVENT_UID);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
1163 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
1164
1165 return old_fsuid;
1166}
1167
1168/*
1169 * Samma på svenska..
1170 */
1171asmlinkage long sys_setfsgid(gid_t gid)
1172{
1173 int old_fsgid;
1174
1175 old_fsgid = current->fsgid;
1176 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
1177 return old_fsgid;
1178
1179 if (gid == current->gid || gid == current->egid ||
1180 gid == current->sgid || gid == current->fsgid ||
1181 capable(CAP_SETGID))
1182 {
1183 if (gid != old_fsgid)
1184 {
Alan Coxd6e71142005-06-23 00:09:43 -07001185 current->mm->dumpable = suid_dumpable;
akpm@osdl.orgd59dd462005-05-01 08:58:47 -07001186 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 }
1188 current->fsgid = gid;
1189 key_fsgid_changed(current);
Matt Helsley9f460802005-11-07 00:59:16 -08001190 proc_id_connector(current, PROC_EVENT_GID);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 }
1192 return old_fsgid;
1193}
1194
1195asmlinkage long sys_times(struct tms __user * tbuf)
1196{
1197 /*
1198 * In the SMP world we might just be unlucky and have one of
1199 * the times increment as we use it. Since the value is an
1200 * atomically safe type this is just fine. Conceptually its
1201 * as if the syscall took an instant longer to occur.
1202 */
1203 if (tbuf) {
1204 struct tms tmp;
Oleg Nesterov35f5cad2006-03-28 16:11:19 -08001205 struct task_struct *tsk = current;
1206 struct task_struct *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 cputime_t utime, stime, cutime, cstime;
1208
Oleg Nesterov7d7185c2006-03-28 16:11:21 -08001209 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesterov35f5cad2006-03-28 16:11:19 -08001210 utime = tsk->signal->utime;
1211 stime = tsk->signal->stime;
1212 t = tsk;
1213 do {
1214 utime = cputime_add(utime, t->utime);
1215 stime = cputime_add(stime, t->stime);
1216 t = next_thread(t);
1217 } while (t != tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218
Oleg Nesterov35f5cad2006-03-28 16:11:19 -08001219 cutime = tsk->signal->cutime;
1220 cstime = tsk->signal->cstime;
1221 spin_unlock_irq(&tsk->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222
1223 tmp.tms_utime = cputime_to_clock_t(utime);
1224 tmp.tms_stime = cputime_to_clock_t(stime);
1225 tmp.tms_cutime = cputime_to_clock_t(cutime);
1226 tmp.tms_cstime = cputime_to_clock_t(cstime);
1227 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1228 return -EFAULT;
1229 }
1230 return (long) jiffies_64_to_clock_t(get_jiffies_64());
1231}
1232
1233/*
1234 * This needs some heavy checking ...
1235 * I just haven't the stomach for it. I also don't fully
1236 * understand sessions/pgrp etc. Let somebody who does explain it.
1237 *
1238 * OK, I think I have the protection semantics right.... this is really
1239 * only important on a multi-user system anyway, to make sure one user
1240 * can't send a signal to a process owned by another. -TYT, 12/12/91
1241 *
1242 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1243 * LBT 04.03.94
1244 */
1245
1246asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1247{
1248 struct task_struct *p;
Oleg Nesterovee0acf92006-01-08 01:03:53 -08001249 struct task_struct *group_leader = current->group_leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 int err = -EINVAL;
1251
1252 if (!pid)
Oleg Nesterovee0acf92006-01-08 01:03:53 -08001253 pid = group_leader->pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 if (!pgid)
1255 pgid = pid;
1256 if (pgid < 0)
1257 return -EINVAL;
1258
1259 /* From this point forward we keep holding onto the tasklist lock
1260 * so that our parent does not change from under us. -DaveM
1261 */
1262 write_lock_irq(&tasklist_lock);
1263
1264 err = -ESRCH;
1265 p = find_task_by_pid(pid);
1266 if (!p)
1267 goto out;
1268
1269 err = -EINVAL;
1270 if (!thread_group_leader(p))
1271 goto out;
1272
Oleg Nesterovf7dd7952006-01-08 01:03:59 -08001273 if (p->real_parent == group_leader) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 err = -EPERM;
Oleg Nesterovee0acf92006-01-08 01:03:53 -08001275 if (p->signal->session != group_leader->signal->session)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 goto out;
1277 err = -EACCES;
1278 if (p->did_exec)
1279 goto out;
1280 } else {
1281 err = -ESRCH;
Oleg Nesterovee0acf92006-01-08 01:03:53 -08001282 if (p != group_leader)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 goto out;
1284 }
1285
1286 err = -EPERM;
1287 if (p->signal->leader)
1288 goto out;
1289
1290 if (pgid != pid) {
1291 struct task_struct *p;
1292
1293 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
Oleg Nesterovee0acf92006-01-08 01:03:53 -08001294 if (p->signal->session == group_leader->signal->session)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 goto ok_pgid;
1296 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1297 goto out;
1298 }
1299
1300ok_pgid:
1301 err = security_task_setpgid(p, pgid);
1302 if (err)
1303 goto out;
1304
1305 if (process_group(p) != pgid) {
1306 detach_pid(p, PIDTYPE_PGID);
1307 p->signal->pgrp = pgid;
1308 attach_pid(p, PIDTYPE_PGID, pgid);
1309 }
1310
1311 err = 0;
1312out:
1313 /* All paths lead to here, thus we are safe. -DaveM */
1314 write_unlock_irq(&tasklist_lock);
1315 return err;
1316}
1317
1318asmlinkage long sys_getpgid(pid_t pid)
1319{
1320 if (!pid) {
1321 return process_group(current);
1322 } else {
1323 int retval;
1324 struct task_struct *p;
1325
1326 read_lock(&tasklist_lock);
1327 p = find_task_by_pid(pid);
1328
1329 retval = -ESRCH;
1330 if (p) {
1331 retval = security_task_getpgid(p);
1332 if (!retval)
1333 retval = process_group(p);
1334 }
1335 read_unlock(&tasklist_lock);
1336 return retval;
1337 }
1338}
1339
1340#ifdef __ARCH_WANT_SYS_GETPGRP
1341
1342asmlinkage long sys_getpgrp(void)
1343{
1344 /* SMP - assuming writes are word atomic this is fine */
1345 return process_group(current);
1346}
1347
1348#endif
1349
1350asmlinkage long sys_getsid(pid_t pid)
1351{
1352 if (!pid) {
1353 return current->signal->session;
1354 } else {
1355 int retval;
1356 struct task_struct *p;
1357
1358 read_lock(&tasklist_lock);
1359 p = find_task_by_pid(pid);
1360
1361 retval = -ESRCH;
1362 if(p) {
1363 retval = security_task_getsid(p);
1364 if (!retval)
1365 retval = p->signal->session;
1366 }
1367 read_unlock(&tasklist_lock);
1368 return retval;
1369 }
1370}
1371
1372asmlinkage long sys_setsid(void)
1373{
Oren Laadane19f2472006-01-08 01:03:58 -08001374 struct task_struct *group_leader = current->group_leader;
Eric W. Biederman390e2ff2006-03-31 02:31:33 -08001375 pid_t session;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 int err = -EPERM;
1377
Ingo Molnar70522e12006-03-23 03:00:31 -08001378 mutex_lock(&tty_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 write_lock_irq(&tasklist_lock);
1380
Eric W. Biederman390e2ff2006-03-31 02:31:33 -08001381 /* Fail if I am already a session leader */
1382 if (group_leader->signal->leader)
1383 goto out;
1384
1385 session = group_leader->pid;
1386 /* Fail if a process group id already exists that equals the
1387 * proposed session id.
1388 *
1389 * Don't check if session id == 1 because kernel threads use this
1390 * session id and so the check will always fail and make it so
1391 * init cannot successfully call setsid.
1392 */
1393 if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 goto out;
1395
Oren Laadane19f2472006-01-08 01:03:58 -08001396 group_leader->signal->leader = 1;
Eric W. Biederman390e2ff2006-03-31 02:31:33 -08001397 __set_special_pids(session, session);
Oren Laadane19f2472006-01-08 01:03:58 -08001398 group_leader->signal->tty = NULL;
1399 group_leader->signal->tty_old_pgrp = 0;
1400 err = process_group(group_leader);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401out:
1402 write_unlock_irq(&tasklist_lock);
Ingo Molnar70522e12006-03-23 03:00:31 -08001403 mutex_unlock(&tty_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404 return err;
1405}
1406
1407/*
1408 * Supplementary group IDs
1409 */
1410
1411/* init to 2 - one for init_task, one to ensure it is never freed */
1412struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1413
1414struct group_info *groups_alloc(int gidsetsize)
1415{
1416 struct group_info *group_info;
1417 int nblocks;
1418 int i;
1419
1420 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1421 /* Make sure we always allocate at least one indirect block pointer */
1422 nblocks = nblocks ? : 1;
1423 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1424 if (!group_info)
1425 return NULL;
1426 group_info->ngroups = gidsetsize;
1427 group_info->nblocks = nblocks;
1428 atomic_set(&group_info->usage, 1);
1429
1430 if (gidsetsize <= NGROUPS_SMALL) {
1431 group_info->blocks[0] = group_info->small_block;
1432 } else {
1433 for (i = 0; i < nblocks; i++) {
1434 gid_t *b;
1435 b = (void *)__get_free_page(GFP_USER);
1436 if (!b)
1437 goto out_undo_partial_alloc;
1438 group_info->blocks[i] = b;
1439 }
1440 }
1441 return group_info;
1442
1443out_undo_partial_alloc:
1444 while (--i >= 0) {
1445 free_page((unsigned long)group_info->blocks[i]);
1446 }
1447 kfree(group_info);
1448 return NULL;
1449}
1450
1451EXPORT_SYMBOL(groups_alloc);
1452
1453void groups_free(struct group_info *group_info)
1454{
1455 if (group_info->blocks[0] != group_info->small_block) {
1456 int i;
1457 for (i = 0; i < group_info->nblocks; i++)
1458 free_page((unsigned long)group_info->blocks[i]);
1459 }
1460 kfree(group_info);
1461}
1462
1463EXPORT_SYMBOL(groups_free);
1464
1465/* export the group_info to a user-space array */
1466static int groups_to_user(gid_t __user *grouplist,
1467 struct group_info *group_info)
1468{
1469 int i;
1470 int count = group_info->ngroups;
1471
1472 for (i = 0; i < group_info->nblocks; i++) {
1473 int cp_count = min(NGROUPS_PER_BLOCK, count);
1474 int off = i * NGROUPS_PER_BLOCK;
1475 int len = cp_count * sizeof(*grouplist);
1476
1477 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1478 return -EFAULT;
1479
1480 count -= cp_count;
1481 }
1482 return 0;
1483}
1484
1485/* fill a group_info from a user-space array - it must be allocated already */
1486static int groups_from_user(struct group_info *group_info,
1487 gid_t __user *grouplist)
1488 {
1489 int i;
1490 int count = group_info->ngroups;
1491
1492 for (i = 0; i < group_info->nblocks; i++) {
1493 int cp_count = min(NGROUPS_PER_BLOCK, count);
1494 int off = i * NGROUPS_PER_BLOCK;
1495 int len = cp_count * sizeof(*grouplist);
1496
1497 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1498 return -EFAULT;
1499
1500 count -= cp_count;
1501 }
1502 return 0;
1503}
1504
Domen Puncerebe8b542005-05-05 16:16:19 -07001505/* a simple Shell sort */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506static void groups_sort(struct group_info *group_info)
1507{
1508 int base, max, stride;
1509 int gidsetsize = group_info->ngroups;
1510
1511 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1512 ; /* nothing */
1513 stride /= 3;
1514
1515 while (stride) {
1516 max = gidsetsize - stride;
1517 for (base = 0; base < max; base++) {
1518 int left = base;
1519 int right = left + stride;
1520 gid_t tmp = GROUP_AT(group_info, right);
1521
1522 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1523 GROUP_AT(group_info, right) =
1524 GROUP_AT(group_info, left);
1525 right = left;
1526 left -= stride;
1527 }
1528 GROUP_AT(group_info, right) = tmp;
1529 }
1530 stride /= 3;
1531 }
1532}
1533
1534/* a simple bsearch */
David Howells3e301482005-06-23 22:00:56 -07001535int groups_search(struct group_info *group_info, gid_t grp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536{
Eric Dumazetd74beb9f2006-03-25 03:08:19 -08001537 unsigned int left, right;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538
1539 if (!group_info)
1540 return 0;
1541
1542 left = 0;
1543 right = group_info->ngroups;
1544 while (left < right) {
Eric Dumazetd74beb9f2006-03-25 03:08:19 -08001545 unsigned int mid = (left+right)/2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546 int cmp = grp - GROUP_AT(group_info, mid);
1547 if (cmp > 0)
1548 left = mid + 1;
1549 else if (cmp < 0)
1550 right = mid;
1551 else
1552 return 1;
1553 }
1554 return 0;
1555}
1556
1557/* validate and set current->group_info */
1558int set_current_groups(struct group_info *group_info)
1559{
1560 int retval;
1561 struct group_info *old_info;
1562
1563 retval = security_task_setgroups(group_info);
1564 if (retval)
1565 return retval;
1566
1567 groups_sort(group_info);
1568 get_group_info(group_info);
1569
1570 task_lock(current);
1571 old_info = current->group_info;
1572 current->group_info = group_info;
1573 task_unlock(current);
1574
1575 put_group_info(old_info);
1576
1577 return 0;
1578}
1579
1580EXPORT_SYMBOL(set_current_groups);
1581
1582asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1583{
1584 int i = 0;
1585
1586 /*
1587 * SMP: Nobody else can change our grouplist. Thus we are
1588 * safe.
1589 */
1590
1591 if (gidsetsize < 0)
1592 return -EINVAL;
1593
1594 /* no need to grab task_lock here; it cannot change */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595 i = current->group_info->ngroups;
1596 if (gidsetsize) {
1597 if (i > gidsetsize) {
1598 i = -EINVAL;
1599 goto out;
1600 }
1601 if (groups_to_user(grouplist, current->group_info)) {
1602 i = -EFAULT;
1603 goto out;
1604 }
1605 }
1606out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 return i;
1608}
1609
1610/*
1611 * SMP: Our groups are copy-on-write. We can set them safely
1612 * without another task interfering.
1613 */
1614
1615asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1616{
1617 struct group_info *group_info;
1618 int retval;
1619
1620 if (!capable(CAP_SETGID))
1621 return -EPERM;
1622 if ((unsigned)gidsetsize > NGROUPS_MAX)
1623 return -EINVAL;
1624
1625 group_info = groups_alloc(gidsetsize);
1626 if (!group_info)
1627 return -ENOMEM;
1628 retval = groups_from_user(group_info, grouplist);
1629 if (retval) {
1630 put_group_info(group_info);
1631 return retval;
1632 }
1633
1634 retval = set_current_groups(group_info);
1635 put_group_info(group_info);
1636
1637 return retval;
1638}
1639
1640/*
1641 * Check whether we're fsgid/egid or in the supplemental group..
1642 */
1643int in_group_p(gid_t grp)
1644{
1645 int retval = 1;
1646 if (grp != current->fsgid) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001647 retval = groups_search(current->group_info, grp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648 }
1649 return retval;
1650}
1651
1652EXPORT_SYMBOL(in_group_p);
1653
1654int in_egroup_p(gid_t grp)
1655{
1656 int retval = 1;
1657 if (grp != current->egid) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 retval = groups_search(current->group_info, grp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 }
1660 return retval;
1661}
1662
1663EXPORT_SYMBOL(in_egroup_p);
1664
1665DECLARE_RWSEM(uts_sem);
1666
David S. Miller393b0722005-11-10 12:47:50 -08001667EXPORT_SYMBOL(uts_sem);
1668
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669asmlinkage long sys_newuname(struct new_utsname __user * name)
1670{
1671 int errno = 0;
1672
1673 down_read(&uts_sem);
1674 if (copy_to_user(name,&system_utsname,sizeof *name))
1675 errno = -EFAULT;
1676 up_read(&uts_sem);
1677 return errno;
1678}
1679
1680asmlinkage long sys_sethostname(char __user *name, int len)
1681{
1682 int errno;
1683 char tmp[__NEW_UTS_LEN];
1684
1685 if (!capable(CAP_SYS_ADMIN))
1686 return -EPERM;
1687 if (len < 0 || len > __NEW_UTS_LEN)
1688 return -EINVAL;
1689 down_write(&uts_sem);
1690 errno = -EFAULT;
1691 if (!copy_from_user(tmp, name, len)) {
1692 memcpy(system_utsname.nodename, tmp, len);
1693 system_utsname.nodename[len] = 0;
1694 errno = 0;
1695 }
1696 up_write(&uts_sem);
1697 return errno;
1698}
1699
1700#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1701
1702asmlinkage long sys_gethostname(char __user *name, int len)
1703{
1704 int i, errno;
1705
1706 if (len < 0)
1707 return -EINVAL;
1708 down_read(&uts_sem);
1709 i = 1 + strlen(system_utsname.nodename);
1710 if (i > len)
1711 i = len;
1712 errno = 0;
1713 if (copy_to_user(name, system_utsname.nodename, i))
1714 errno = -EFAULT;
1715 up_read(&uts_sem);
1716 return errno;
1717}
1718
1719#endif
1720
1721/*
1722 * Only setdomainname; getdomainname can be implemented by calling
1723 * uname()
1724 */
1725asmlinkage long sys_setdomainname(char __user *name, int len)
1726{
1727 int errno;
1728 char tmp[__NEW_UTS_LEN];
1729
1730 if (!capable(CAP_SYS_ADMIN))
1731 return -EPERM;
1732 if (len < 0 || len > __NEW_UTS_LEN)
1733 return -EINVAL;
1734
1735 down_write(&uts_sem);
1736 errno = -EFAULT;
1737 if (!copy_from_user(tmp, name, len)) {
1738 memcpy(system_utsname.domainname, tmp, len);
1739 system_utsname.domainname[len] = 0;
1740 errno = 0;
1741 }
1742 up_write(&uts_sem);
1743 return errno;
1744}
1745
1746asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1747{
1748 if (resource >= RLIM_NLIMITS)
1749 return -EINVAL;
1750 else {
1751 struct rlimit value;
1752 task_lock(current->group_leader);
1753 value = current->signal->rlim[resource];
1754 task_unlock(current->group_leader);
1755 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1756 }
1757}
1758
1759#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1760
1761/*
1762 * Back compatibility for getrlimit. Needed for some apps.
1763 */
1764
1765asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1766{
1767 struct rlimit x;
1768 if (resource >= RLIM_NLIMITS)
1769 return -EINVAL;
1770
1771 task_lock(current->group_leader);
1772 x = current->signal->rlim[resource];
1773 task_unlock(current->group_leader);
1774 if(x.rlim_cur > 0x7FFFFFFF)
1775 x.rlim_cur = 0x7FFFFFFF;
1776 if(x.rlim_max > 0x7FFFFFFF)
1777 x.rlim_max = 0x7FFFFFFF;
1778 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1779}
1780
1781#endif
1782
1783asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1784{
1785 struct rlimit new_rlim, *old_rlim;
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001786 unsigned long it_prof_secs;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 int retval;
1788
1789 if (resource >= RLIM_NLIMITS)
1790 return -EINVAL;
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001791 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 return -EFAULT;
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001793 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1794 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 old_rlim = current->signal->rlim + resource;
1796 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1797 !capable(CAP_SYS_RESOURCE))
1798 return -EPERM;
1799 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001800 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801
1802 retval = security_task_setrlimit(resource, &new_rlim);
1803 if (retval)
1804 return retval;
1805
1806 task_lock(current->group_leader);
1807 *old_rlim = new_rlim;
1808 task_unlock(current->group_leader);
1809
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001810 if (resource != RLIMIT_CPU)
1811 goto out;
Andrew Mortond3561f72006-03-24 03:18:36 -08001812
1813 /*
1814 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1815 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1816 * very long-standing error, and fixing it now risks breakage of
1817 * applications, so we live with it
1818 */
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001819 if (new_rlim.rlim_cur == RLIM_INFINITY)
1820 goto out;
1821
1822 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1823 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
Andrew Mortone0661112006-03-24 03:18:35 -08001824 unsigned long rlim_cur = new_rlim.rlim_cur;
1825 cputime_t cputime;
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001826
Andrew Mortone0661112006-03-24 03:18:35 -08001827 if (rlim_cur == 0) {
1828 /*
1829 * The caller is asking for an immediate RLIMIT_CPU
1830 * expiry. But we use the zero value to mean "it was
1831 * never set". So let's cheat and make it one second
1832 * instead
1833 */
1834 rlim_cur = 1;
1835 }
1836 cputime = secs_to_cputime(rlim_cur);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837 read_lock(&tasklist_lock);
1838 spin_lock_irq(&current->sighand->siglock);
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001839 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 spin_unlock_irq(&current->sighand->siglock);
1841 read_unlock(&tasklist_lock);
1842 }
Andrew Mortonec9e16b2006-03-24 03:18:34 -08001843out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 return 0;
1845}
1846
1847/*
1848 * It would make sense to put struct rusage in the task_struct,
1849 * except that would make the task_struct be *really big*. After
1850 * task_struct gets moved into malloc'ed memory, it would
1851 * make sense to do this. It will make moving the rest of the information
1852 * a lot simpler! (Which we're not doing right now because we're not
1853 * measuring them yet).
1854 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1856 * races with threads incrementing their own counters. But since word
1857 * reads are atomic, we either get new values or old values and we don't
1858 * care which for the sums. We always take the siglock to protect reading
1859 * the c* fields from p->signal from races with exit.c updating those
1860 * fields when reaping, so a sample either gets all the additions of a
1861 * given child after it's reaped, or none so this sample is before reaping.
Ravikiran G Thirumalai2dd0ebc2006-03-23 03:00:13 -08001862 *
Ravikiran G Thirumalaide047c12006-06-22 14:47:26 -07001863 * Locking:
1864 * We need to take the siglock for CHILDEREN, SELF and BOTH
1865 * for the cases current multithreaded, non-current single threaded
1866 * non-current multithreaded. Thread traversal is now safe with
1867 * the siglock held.
1868 * Strictly speaking, we donot need to take the siglock if we are current and
1869 * single threaded, as no one else can take our signal_struct away, no one
1870 * else can reap the children to update signal->c* counters, and no one else
1871 * can race with the signal-> fields. If we do not take any lock, the
1872 * signal-> fields could be read out of order while another thread was just
1873 * exiting. So we should place a read memory barrier when we avoid the lock.
1874 * On the writer side, write memory barrier is implied in __exit_signal
1875 * as __exit_signal releases the siglock spinlock after updating the signal->
1876 * fields. But we don't do this yet to keep things simple.
Ravikiran G Thirumalai2dd0ebc2006-03-23 03:00:13 -08001877 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 */
1879
1880static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1881{
1882 struct task_struct *t;
1883 unsigned long flags;
1884 cputime_t utime, stime;
1885
1886 memset((char *) r, 0, sizeof *r);
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001887 utime = stime = cputime_zero;
1888
Ravikiran G Thirumalaide047c12006-06-22 14:47:26 -07001889 rcu_read_lock();
1890 if (!lock_task_sighand(p, &flags)) {
1891 rcu_read_unlock();
1892 return;
1893 }
Ravikiran G Thirumalai2dd0ebc2006-03-23 03:00:13 -08001894
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 switch (who) {
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001896 case RUSAGE_BOTH:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 case RUSAGE_CHILDREN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 utime = p->signal->cutime;
1899 stime = p->signal->cstime;
1900 r->ru_nvcsw = p->signal->cnvcsw;
1901 r->ru_nivcsw = p->signal->cnivcsw;
1902 r->ru_minflt = p->signal->cmin_flt;
1903 r->ru_majflt = p->signal->cmaj_flt;
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001904
1905 if (who == RUSAGE_CHILDREN)
1906 break;
1907
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 case RUSAGE_SELF:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909 utime = cputime_add(utime, p->signal->utime);
1910 stime = cputime_add(stime, p->signal->stime);
1911 r->ru_nvcsw += p->signal->nvcsw;
1912 r->ru_nivcsw += p->signal->nivcsw;
1913 r->ru_minflt += p->signal->min_flt;
1914 r->ru_majflt += p->signal->maj_flt;
1915 t = p;
1916 do {
1917 utime = cputime_add(utime, t->utime);
1918 stime = cputime_add(stime, t->stime);
1919 r->ru_nvcsw += t->nvcsw;
1920 r->ru_nivcsw += t->nivcsw;
1921 r->ru_minflt += t->min_flt;
1922 r->ru_majflt += t->maj_flt;
1923 t = next_thread(t);
1924 } while (t != p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 break;
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001926
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927 default:
1928 BUG();
1929 }
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001930
Ravikiran G Thirumalaide047c12006-06-22 14:47:26 -07001931 unlock_task_sighand(p, &flags);
1932 rcu_read_unlock();
1933
Oleg Nesterov0f59cc42006-01-08 01:05:15 -08001934 cputime_to_timeval(utime, &r->ru_utime);
1935 cputime_to_timeval(stime, &r->ru_stime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936}
1937
1938int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1939{
1940 struct rusage r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 k_getrusage(p, who, &r);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1943}
1944
1945asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1946{
1947 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1948 return -EINVAL;
1949 return getrusage(current, who, ru);
1950}
1951
1952asmlinkage long sys_umask(int mask)
1953{
1954 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1955 return mask;
1956}
1957
1958asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1959 unsigned long arg4, unsigned long arg5)
1960{
1961 long error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962
1963 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1964 if (error)
1965 return error;
1966
1967 switch (option) {
1968 case PR_SET_PDEATHSIG:
Jesper Juhl0730ded2005-09-06 15:17:37 -07001969 if (!valid_signal(arg2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 error = -EINVAL;
1971 break;
1972 }
Jesper Juhl0730ded2005-09-06 15:17:37 -07001973 current->pdeath_signal = arg2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 break;
1975 case PR_GET_PDEATHSIG:
1976 error = put_user(current->pdeath_signal, (int __user *)arg2);
1977 break;
1978 case PR_GET_DUMPABLE:
Michael Kerrisk2030c0f2005-09-16 19:28:02 -07001979 error = current->mm->dumpable;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 break;
1981 case PR_SET_DUMPABLE:
Alan Coxd6e71142005-06-23 00:09:43 -07001982 if (arg2 < 0 || arg2 > 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983 error = -EINVAL;
1984 break;
1985 }
1986 current->mm->dumpable = arg2;
1987 break;
1988
1989 case PR_SET_UNALIGN:
1990 error = SET_UNALIGN_CTL(current, arg2);
1991 break;
1992 case PR_GET_UNALIGN:
1993 error = GET_UNALIGN_CTL(current, arg2);
1994 break;
1995 case PR_SET_FPEMU:
1996 error = SET_FPEMU_CTL(current, arg2);
1997 break;
1998 case PR_GET_FPEMU:
1999 error = GET_FPEMU_CTL(current, arg2);
2000 break;
2001 case PR_SET_FPEXC:
2002 error = SET_FPEXC_CTL(current, arg2);
2003 break;
2004 case PR_GET_FPEXC:
2005 error = GET_FPEXC_CTL(current, arg2);
2006 break;
2007 case PR_GET_TIMING:
2008 error = PR_TIMING_STATISTICAL;
2009 break;
2010 case PR_SET_TIMING:
2011 if (arg2 == PR_TIMING_STATISTICAL)
2012 error = 0;
2013 else
2014 error = -EINVAL;
2015 break;
2016
2017 case PR_GET_KEEPCAPS:
2018 if (current->keep_capabilities)
2019 error = 1;
2020 break;
2021 case PR_SET_KEEPCAPS:
2022 if (arg2 != 0 && arg2 != 1) {
2023 error = -EINVAL;
2024 break;
2025 }
2026 current->keep_capabilities = arg2;
2027 break;
2028 case PR_SET_NAME: {
2029 struct task_struct *me = current;
2030 unsigned char ncomm[sizeof(me->comm)];
2031
2032 ncomm[sizeof(me->comm)-1] = 0;
2033 if (strncpy_from_user(ncomm, (char __user *)arg2,
2034 sizeof(me->comm)-1) < 0)
2035 return -EFAULT;
2036 set_task_comm(me, ncomm);
2037 return 0;
2038 }
2039 case PR_GET_NAME: {
2040 struct task_struct *me = current;
2041 unsigned char tcomm[sizeof(me->comm)];
2042
2043 get_task_comm(tcomm, me);
2044 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
2045 return -EFAULT;
2046 return 0;
2047 }
2048 default:
2049 error = -EINVAL;
2050 break;
2051 }
2052 return error;
2053}