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Linux v2.6.13-rc3
[pohmelfs.git] / kernel / sys.c
blob9a24374c23bc4f69116d264991689b1aaa9c38fe
1 /*
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>
19 #include <linux/kernel.h>
20 #include <linux/kexec.h>
21 #include <linux/workqueue.h>
22 #include <linux/device.h>
23 #include <linux/key.h>
24 #include <linux/times.h>
25 #include <linux/posix-timers.h>
26 #include <linux/security.h>
27 #include <linux/dcookies.h>
28 #include <linux/suspend.h>
29 #include <linux/tty.h>
30 #include <linux/signal.h>
31
32 #include <linux/compat.h>
33 #include <linux/syscalls.h>
34
35 #include <asm/uaccess.h>
36 #include <asm/io.h>
37 #include <asm/unistd.h>
38
39 #ifndef SET_UNALIGN_CTL
40 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
41 #endif
42 #ifndef GET_UNALIGN_CTL
43 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
44 #endif
45 #ifndef SET_FPEMU_CTL
46 # define SET_FPEMU_CTL(a,b) (-EINVAL)
47 #endif
48 #ifndef GET_FPEMU_CTL
49 # define GET_FPEMU_CTL(a,b) (-EINVAL)
50 #endif
51 #ifndef SET_FPEXC_CTL
52 # define SET_FPEXC_CTL(a,b) (-EINVAL)
53 #endif
54 #ifndef GET_FPEXC_CTL
55 # define GET_FPEXC_CTL(a,b) (-EINVAL)
56 #endif
57
58 /*
59 * this is where the system-wide overflow UID and GID are defined, for
60 * architectures that now have 32-bit UID/GID but didn't in the past
61 */
62
63 int overflowuid = DEFAULT_OVERFLOWUID;
64 int overflowgid = DEFAULT_OVERFLOWGID;
65
66 #ifdef CONFIG_UID16
67 EXPORT_SYMBOL(overflowuid);
68 EXPORT_SYMBOL(overflowgid);
69 #endif
70
71 /*
72 * the same as above, but for filesystems which can only store a 16-bit
73 * UID and GID. as such, this is needed on all architectures
74 */
75
76 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
77 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
78
79 EXPORT_SYMBOL(fs_overflowuid);
80 EXPORT_SYMBOL(fs_overflowgid);
81
82 /*
83 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
84 */
85
86 int C_A_D = 1;
87 int cad_pid = 1;
88
89 /*
90 * Notifier list for kernel code which wants to be called
91 * at shutdown. This is used to stop any idling DMA operations
92 * and the like.
93 */
94
95 static struct notifier_block *reboot_notifier_list;
96 static DEFINE_RWLOCK(notifier_lock);
97
98 /**
99 * notifier_chain_register - Add notifier to a notifier chain
100 * @list: Pointer to root list pointer
101 * @n: New entry in notifier chain
102 *
103 * Adds a notifier to a notifier chain.
104 *
105 * Currently always returns zero.
106 */
107
108 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
109 {
110 write_lock(&notifier_lock);
111 while(*list)
112 {
113 if(n->priority > (*list)->priority)
114 break;
115 list= &((*list)->next);
116 }
117 n->next = *list;
118 *list=n;
119 write_unlock(&notifier_lock);
120 return 0;
121 }
122
123 EXPORT_SYMBOL(notifier_chain_register);
124
125 /**
126 * notifier_chain_unregister - Remove notifier from a notifier chain
127 * @nl: Pointer to root list pointer
128 * @n: New entry in notifier chain
129 *
130 * Removes a notifier from a notifier chain.
131 *
132 * Returns zero on success, or %-ENOENT on failure.
133 */
134
135 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
136 {
137 write_lock(&notifier_lock);
138 while((*nl)!=NULL)
139 {
140 if((*nl)==n)
141 {
142 *nl=n->next;
143 write_unlock(&notifier_lock);
144 return 0;
145 }
146 nl=&((*nl)->next);
147 }
148 write_unlock(&notifier_lock);
149 return -ENOENT;
150 }
151
152 EXPORT_SYMBOL(notifier_chain_unregister);
153
154 /**
155 * notifier_call_chain - Call functions in a notifier chain
156 * @n: Pointer to root pointer of notifier chain
157 * @val: Value passed unmodified to notifier function
158 * @v: Pointer passed unmodified to notifier function
159 *
160 * Calls each function in a notifier chain in turn.
161 *
162 * If the return value of the notifier can be and'd
163 * with %NOTIFY_STOP_MASK, then notifier_call_chain
164 * will return immediately, with the return value of
165 * the notifier function which halted execution.
166 * Otherwise, the return value is the return value
167 * of the last notifier function called.
168 */
169
170 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
171 {
172 int ret=NOTIFY_DONE;
173 struct notifier_block *nb = *n;
174
175 while(nb)
176 {
177 ret=nb->notifier_call(nb,val,v);
178 if(ret&NOTIFY_STOP_MASK)
179 {
180 return ret;
181 }
182 nb=nb->next;
183 }
184 return ret;
185 }
186
187 EXPORT_SYMBOL(notifier_call_chain);
188
189 /**
190 * register_reboot_notifier - Register function to be called at reboot time
191 * @nb: Info about notifier function to be called
192 *
193 * Registers a function with the list of functions
194 * to be called at reboot time.
195 *
196 * Currently always returns zero, as notifier_chain_register
197 * always returns zero.
198 */
199
200 int register_reboot_notifier(struct notifier_block * nb)
201 {
202 return notifier_chain_register(&reboot_notifier_list, nb);
203 }
204
205 EXPORT_SYMBOL(register_reboot_notifier);
206
207 /**
208 * unregister_reboot_notifier - Unregister previously registered reboot notifier
209 * @nb: Hook to be unregistered
210 *
211 * Unregisters a previously registered reboot
212 * notifier function.
213 *
214 * Returns zero on success, or %-ENOENT on failure.
215 */
216
217 int unregister_reboot_notifier(struct notifier_block * nb)
218 {
219 return notifier_chain_unregister(&reboot_notifier_list, nb);
220 }
221
222 EXPORT_SYMBOL(unregister_reboot_notifier);
223
224 static int set_one_prio(struct task_struct *p, int niceval, int error)
225 {
226 int no_nice;
227
228 if (p->uid != current->euid &&
229 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
230 error = -EPERM;
231 goto out;
232 }
233 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
234 error = -EACCES;
235 goto out;
236 }
237 no_nice = security_task_setnice(p, niceval);
238 if (no_nice) {
239 error = no_nice;
240 goto out;
241 }
242 if (error == -ESRCH)
243 error = 0;
244 set_user_nice(p, niceval);
245 out:
246 return error;
247 }
248
249 asmlinkage long sys_setpriority(int which, int who, int niceval)
250 {
251 struct task_struct *g, *p;
252 struct user_struct *user;
253 int error = -EINVAL;
254
255 if (which > 2 || which < 0)
256 goto out;
257
258 /* normalize: avoid signed division (rounding problems) */
259 error = -ESRCH;
260 if (niceval < -20)
261 niceval = -20;
262 if (niceval > 19)
263 niceval = 19;
264
265 read_lock(&tasklist_lock);
266 switch (which) {
267 case PRIO_PROCESS:
268 if (!who)
269 who = current->pid;
270 p = find_task_by_pid(who);
271 if (p)
272 error = set_one_prio(p, niceval, error);
273 break;
274 case PRIO_PGRP:
275 if (!who)
276 who = process_group(current);
277 do_each_task_pid(who, PIDTYPE_PGID, p) {
278 error = set_one_prio(p, niceval, error);
279 } while_each_task_pid(who, PIDTYPE_PGID, p);
280 break;
281 case PRIO_USER:
282 user = current->user;
283 if (!who)
284 who = current->uid;
285 else
286 if ((who != current->uid) && !(user = find_user(who)))
287 goto out_unlock; /* No processes for this user */
288
289 do_each_thread(g, p)
290 if (p->uid == who)
291 error = set_one_prio(p, niceval, error);
292 while_each_thread(g, p);
293 if (who != current->uid)
294 free_uid(user); /* For find_user() */
295 break;
296 }
297 out_unlock:
298 read_unlock(&tasklist_lock);
299 out:
300 return error;
301 }
302
303 /*
304 * Ugh. To avoid negative return values, "getpriority()" will
305 * not return the normal nice-value, but a negated value that
306 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
307 * to stay compatible.
308 */
309 asmlinkage long sys_getpriority(int which, int who)
310 {
311 struct task_struct *g, *p;
312 struct user_struct *user;
313 long niceval, retval = -ESRCH;
314
315 if (which > 2 || which < 0)
316 return -EINVAL;
317
318 read_lock(&tasklist_lock);
319 switch (which) {
320 case PRIO_PROCESS:
321 if (!who)
322 who = current->pid;
323 p = find_task_by_pid(who);
324 if (p) {
325 niceval = 20 - task_nice(p);
326 if (niceval > retval)
327 retval = niceval;
328 }
329 break;
330 case PRIO_PGRP:
331 if (!who)
332 who = process_group(current);
333 do_each_task_pid(who, PIDTYPE_PGID, p) {
334 niceval = 20 - task_nice(p);
335 if (niceval > retval)
336 retval = niceval;
337 } while_each_task_pid(who, PIDTYPE_PGID, p);
338 break;
339 case PRIO_USER:
340 user = current->user;
341 if (!who)
342 who = current->uid;
343 else
344 if ((who != current->uid) && !(user = find_user(who)))
345 goto out_unlock; /* No processes for this user */
346
347 do_each_thread(g, p)
348 if (p->uid == who) {
349 niceval = 20 - task_nice(p);
350 if (niceval > retval)
351 retval = niceval;
352 }
353 while_each_thread(g, p);
354 if (who != current->uid)
355 free_uid(user); /* for find_user() */
356 break;
357 }
358 out_unlock:
359 read_unlock(&tasklist_lock);
360
361 return retval;
362 }
363
364
365 /*
366 * Reboot system call: for obvious reasons only root may call it,
367 * and even root needs to set up some magic numbers in the registers
368 * so that some mistake won't make this reboot the whole machine.
369 * You can also set the meaning of the ctrl-alt-del-key here.
370 *
371 * reboot doesn't sync: do that yourself before calling this.
372 */
373 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
374 {
375 char buffer[256];
376
377 /* We only trust the superuser with rebooting the system. */
378 if (!capable(CAP_SYS_BOOT))
379 return -EPERM;
380
381 /* For safety, we require "magic" arguments. */
382 if (magic1 != LINUX_REBOOT_MAGIC1 ||
383 (magic2 != LINUX_REBOOT_MAGIC2 &&
384 magic2 != LINUX_REBOOT_MAGIC2A &&
385 magic2 != LINUX_REBOOT_MAGIC2B &&
386 magic2 != LINUX_REBOOT_MAGIC2C))
387 return -EINVAL;
388
389 lock_kernel();
390 switch (cmd) {
391 case LINUX_REBOOT_CMD_RESTART:
392 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
393 system_state = SYSTEM_RESTART;
394 device_shutdown();
395 printk(KERN_EMERG "Restarting system.\n");
396 machine_restart(NULL);
397 break;
398
399 case LINUX_REBOOT_CMD_CAD_ON:
400 C_A_D = 1;
401 break;
402
403 case LINUX_REBOOT_CMD_CAD_OFF:
404 C_A_D = 0;
405 break;
406
407 case LINUX_REBOOT_CMD_HALT:
408 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
409 system_state = SYSTEM_HALT;
410 device_suspend(PMSG_SUSPEND);
411 device_shutdown();
412 printk(KERN_EMERG "System halted.\n");
413 machine_halt();
414 unlock_kernel();
415 do_exit(0);
416 break;
417
418 case LINUX_REBOOT_CMD_POWER_OFF:
419 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
420 system_state = SYSTEM_POWER_OFF;
421 device_suspend(PMSG_SUSPEND);
422 device_shutdown();
423 printk(KERN_EMERG "Power down.\n");
424 machine_power_off();
425 unlock_kernel();
426 do_exit(0);
427 break;
428
429 case LINUX_REBOOT_CMD_RESTART2:
430 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
431 unlock_kernel();
432 return -EFAULT;
433 }
434 buffer[sizeof(buffer) - 1] = '\0';
435
436 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
437 system_state = SYSTEM_RESTART;
438 device_suspend(PMSG_FREEZE);
439 device_shutdown();
440 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
441 machine_restart(buffer);
442 break;
443
444 #ifdef CONFIG_KEXEC
445 case LINUX_REBOOT_CMD_KEXEC:
446 {
447 struct kimage *image;
448 image = xchg(&kexec_image, 0);
449 if (!image) {
450 unlock_kernel();
451 return -EINVAL;
452 }
453 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
454 system_state = SYSTEM_RESTART;
455 device_shutdown();
456 printk(KERN_EMERG "Starting new kernel\n");
457 machine_shutdown();
458 machine_kexec(image);
459 break;
460 }
461 #endif
462 #ifdef CONFIG_SOFTWARE_SUSPEND
463 case LINUX_REBOOT_CMD_SW_SUSPEND:
464 {
465 int ret = software_suspend();
466 unlock_kernel();
467 return ret;
468 }
469 #endif
470
471 default:
472 unlock_kernel();
473 return -EINVAL;
474 }
475 unlock_kernel();
476 return 0;
477 }
478
479 static void deferred_cad(void *dummy)
480 {
481 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
482 machine_restart(NULL);
483 }
484
485 /*
486 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
487 * As it's called within an interrupt, it may NOT sync: the only choice
488 * is whether to reboot at once, or just ignore the ctrl-alt-del.
489 */
490 void ctrl_alt_del(void)
491 {
492 static DECLARE_WORK(cad_work, deferred_cad, NULL);
493
494 if (C_A_D)
495 schedule_work(&cad_work);
496 else
497 kill_proc(cad_pid, SIGINT, 1);
498 }
499
500
501 /*
502 * Unprivileged users may change the real gid to the effective gid
503 * or vice versa. (BSD-style)
504 *
505 * If you set the real gid at all, or set the effective gid to a value not
506 * equal to the real gid, then the saved gid is set to the new effective gid.
507 *
508 * This makes it possible for a setgid program to completely drop its
509 * privileges, which is often a useful assertion to make when you are doing
510 * a security audit over a program.
511 *
512 * The general idea is that a program which uses just setregid() will be
513 * 100% compatible with BSD. A program which uses just setgid() will be
514 * 100% compatible with POSIX with saved IDs.
515 *
516 * SMP: There are not races, the GIDs are checked only by filesystem
517 * operations (as far as semantic preservation is concerned).
518 */
519 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
520 {
521 int old_rgid = current->gid;
522 int old_egid = current->egid;
523 int new_rgid = old_rgid;
524 int new_egid = old_egid;
525 int retval;
526
527 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
528 if (retval)
529 return retval;
530
531 if (rgid != (gid_t) -1) {
532 if ((old_rgid == rgid) ||
533 (current->egid==rgid) ||
534 capable(CAP_SETGID))
535 new_rgid = rgid;
536 else
537 return -EPERM;
538 }
539 if (egid != (gid_t) -1) {
540 if ((old_rgid == egid) ||
541 (current->egid == egid) ||
542 (current->sgid == egid) ||
543 capable(CAP_SETGID))
544 new_egid = egid;
545 else {
546 return -EPERM;
547 }
548 }
549 if (new_egid != old_egid)
550 {
551 current->mm->dumpable = suid_dumpable;
552 smp_wmb();
553 }
554 if (rgid != (gid_t) -1 ||
555 (egid != (gid_t) -1 && egid != old_rgid))
556 current->sgid = new_egid;
557 current->fsgid = new_egid;
558 current->egid = new_egid;
559 current->gid = new_rgid;
560 key_fsgid_changed(current);
561 return 0;
562 }
563
564 /*
565 * setgid() is implemented like SysV w/ SAVED_IDS
566 *
567 * SMP: Same implicit races as above.
568 */
569 asmlinkage long sys_setgid(gid_t gid)
570 {
571 int old_egid = current->egid;
572 int retval;
573
574 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
575 if (retval)
576 return retval;
577
578 if (capable(CAP_SETGID))
579 {
580 if(old_egid != gid)
581 {
582 current->mm->dumpable = suid_dumpable;
583 smp_wmb();
584 }
585 current->gid = current->egid = current->sgid = current->fsgid = gid;
586 }
587 else if ((gid == current->gid) || (gid == current->sgid))
588 {
589 if(old_egid != gid)
590 {
591 current->mm->dumpable = suid_dumpable;
592 smp_wmb();
593 }
594 current->egid = current->fsgid = gid;
595 }
596 else
597 return -EPERM;
598
599 key_fsgid_changed(current);
600 return 0;
601 }
602
603 static int set_user(uid_t new_ruid, int dumpclear)
604 {
605 struct user_struct *new_user;
606
607 new_user = alloc_uid(new_ruid);
608 if (!new_user)
609 return -EAGAIN;
610
611 if (atomic_read(&new_user->processes) >=
612 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
613 new_user != &root_user) {
614 free_uid(new_user);
615 return -EAGAIN;
616 }
617
618 switch_uid(new_user);
619
620 if(dumpclear)
621 {
622 current->mm->dumpable = suid_dumpable;
623 smp_wmb();
624 }
625 current->uid = new_ruid;
626 return 0;
627 }
628
629 /*
630 * Unprivileged users may change the real uid to the effective uid
631 * or vice versa. (BSD-style)
632 *
633 * If you set the real uid at all, or set the effective uid to a value not
634 * equal to the real uid, then the saved uid is set to the new effective uid.
635 *
636 * This makes it possible for a setuid program to completely drop its
637 * privileges, which is often a useful assertion to make when you are doing
638 * a security audit over a program.
639 *
640 * The general idea is that a program which uses just setreuid() will be
641 * 100% compatible with BSD. A program which uses just setuid() will be
642 * 100% compatible with POSIX with saved IDs.
643 */
644 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
645 {
646 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
647 int retval;
648
649 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
650 if (retval)
651 return retval;
652
653 new_ruid = old_ruid = current->uid;
654 new_euid = old_euid = current->euid;
655 old_suid = current->suid;
656
657 if (ruid != (uid_t) -1) {
658 new_ruid = ruid;
659 if ((old_ruid != ruid) &&
660 (current->euid != ruid) &&
661 !capable(CAP_SETUID))
662 return -EPERM;
663 }
664
665 if (euid != (uid_t) -1) {
666 new_euid = euid;
667 if ((old_ruid != euid) &&
668 (current->euid != euid) &&
669 (current->suid != euid) &&
670 !capable(CAP_SETUID))
671 return -EPERM;
672 }
673
674 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
675 return -EAGAIN;
676
677 if (new_euid != old_euid)
678 {
679 current->mm->dumpable = suid_dumpable;
680 smp_wmb();
681 }
682 current->fsuid = current->euid = new_euid;
683 if (ruid != (uid_t) -1 ||
684 (euid != (uid_t) -1 && euid != old_ruid))
685 current->suid = current->euid;
686 current->fsuid = current->euid;
687
688 key_fsuid_changed(current);
689
690 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
691 }
692
693
694
695 /*
696 * setuid() is implemented like SysV with SAVED_IDS
697 *
698 * Note that SAVED_ID's is deficient in that a setuid root program
699 * like sendmail, for example, cannot set its uid to be a normal
700 * user and then switch back, because if you're root, setuid() sets
701 * the saved uid too. If you don't like this, blame the bright people
702 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
703 * will allow a root program to temporarily drop privileges and be able to
704 * regain them by swapping the real and effective uid.
705 */
706 asmlinkage long sys_setuid(uid_t uid)
707 {
708 int old_euid = current->euid;
709 int old_ruid, old_suid, new_ruid, new_suid;
710 int retval;
711
712 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
713 if (retval)
714 return retval;
715
716 old_ruid = new_ruid = current->uid;
717 old_suid = current->suid;
718 new_suid = old_suid;
719
720 if (capable(CAP_SETUID)) {
721 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
722 return -EAGAIN;
723 new_suid = uid;
724 } else if ((uid != current->uid) && (uid != new_suid))
725 return -EPERM;
726
727 if (old_euid != uid)
728 {
729 current->mm->dumpable = suid_dumpable;
730 smp_wmb();
731 }
732 current->fsuid = current->euid = uid;
733 current->suid = new_suid;
734
735 key_fsuid_changed(current);
736
737 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
738 }
739
740
741 /*
742 * This function implements a generic ability to update ruid, euid,
743 * and suid. This allows you to implement the 4.4 compatible seteuid().
744 */
745 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
746 {
747 int old_ruid = current->uid;
748 int old_euid = current->euid;
749 int old_suid = current->suid;
750 int retval;
751
752 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
753 if (retval)
754 return retval;
755
756 if (!capable(CAP_SETUID)) {
757 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
758 (ruid != current->euid) && (ruid != current->suid))
759 return -EPERM;
760 if ((euid != (uid_t) -1) && (euid != current->uid) &&
761 (euid != current->euid) && (euid != current->suid))
762 return -EPERM;
763 if ((suid != (uid_t) -1) && (suid != current->uid) &&
764 (suid != current->euid) && (suid != current->suid))
765 return -EPERM;
766 }
767 if (ruid != (uid_t) -1) {
768 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
769 return -EAGAIN;
770 }
771 if (euid != (uid_t) -1) {
772 if (euid != current->euid)
773 {
774 current->mm->dumpable = suid_dumpable;
775 smp_wmb();
776 }
777 current->euid = euid;
778 }
779 current->fsuid = current->euid;
780 if (suid != (uid_t) -1)
781 current->suid = suid;
782
783 key_fsuid_changed(current);
784
785 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
786 }
787
788 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
789 {
790 int retval;
791
792 if (!(retval = put_user(current->uid, ruid)) &&
793 !(retval = put_user(current->euid, euid)))
794 retval = put_user(current->suid, suid);
795
796 return retval;
797 }
798
799 /*
800 * Same as above, but for rgid, egid, sgid.
801 */
802 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
803 {
804 int retval;
805
806 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
807 if (retval)
808 return retval;
809
810 if (!capable(CAP_SETGID)) {
811 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
812 (rgid != current->egid) && (rgid != current->sgid))
813 return -EPERM;
814 if ((egid != (gid_t) -1) && (egid != current->gid) &&
815 (egid != current->egid) && (egid != current->sgid))
816 return -EPERM;
817 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
818 (sgid != current->egid) && (sgid != current->sgid))
819 return -EPERM;
820 }
821 if (egid != (gid_t) -1) {
822 if (egid != current->egid)
823 {
824 current->mm->dumpable = suid_dumpable;
825 smp_wmb();
826 }
827 current->egid = egid;
828 }
829 current->fsgid = current->egid;
830 if (rgid != (gid_t) -1)
831 current->gid = rgid;
832 if (sgid != (gid_t) -1)
833 current->sgid = sgid;
834
835 key_fsgid_changed(current);
836 return 0;
837 }
838
839 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
840 {
841 int retval;
842
843 if (!(retval = put_user(current->gid, rgid)) &&
844 !(retval = put_user(current->egid, egid)))
845 retval = put_user(current->sgid, sgid);
846
847 return retval;
848 }
849
850
851 /*
852 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
853 * is used for "access()" and for the NFS daemon (letting nfsd stay at
854 * whatever uid it wants to). It normally shadows "euid", except when
855 * explicitly set by setfsuid() or for access..
856 */
857 asmlinkage long sys_setfsuid(uid_t uid)
858 {
859 int old_fsuid;
860
861 old_fsuid = current->fsuid;
862 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
863 return old_fsuid;
864
865 if (uid == current->uid || uid == current->euid ||
866 uid == current->suid || uid == current->fsuid ||
867 capable(CAP_SETUID))
868 {
869 if (uid != old_fsuid)
870 {
871 current->mm->dumpable = suid_dumpable;
872 smp_wmb();
873 }
874 current->fsuid = uid;
875 }
876
877 key_fsuid_changed(current);
878
879 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
880
881 return old_fsuid;
882 }
883
884 /*
885 * Samma på svenska..
886 */
887 asmlinkage long sys_setfsgid(gid_t gid)
888 {
889 int old_fsgid;
890
891 old_fsgid = current->fsgid;
892 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
893 return old_fsgid;
894
895 if (gid == current->gid || gid == current->egid ||
896 gid == current->sgid || gid == current->fsgid ||
897 capable(CAP_SETGID))
898 {
899 if (gid != old_fsgid)
900 {
901 current->mm->dumpable = suid_dumpable;
902 smp_wmb();
903 }
904 current->fsgid = gid;
905 key_fsgid_changed(current);
906 }
907 return old_fsgid;
908 }
909
910 asmlinkage long sys_times(struct tms __user * tbuf)
911 {
912 /*
913 * In the SMP world we might just be unlucky and have one of
914 * the times increment as we use it. Since the value is an
915 * atomically safe type this is just fine. Conceptually its
916 * as if the syscall took an instant longer to occur.
917 */
918 if (tbuf) {
919 struct tms tmp;
920 cputime_t utime, stime, cutime, cstime;
921
922 #ifdef CONFIG_SMP
923 if (thread_group_empty(current)) {
924 /*
925 * Single thread case without the use of any locks.
926 *
927 * We may race with release_task if two threads are
928 * executing. However, release task first adds up the
929 * counters (__exit_signal) before removing the task
930 * from the process tasklist (__unhash_process).
931 * __exit_signal also acquires and releases the
932 * siglock which results in the proper memory ordering
933 * so that the list modifications are always visible
934 * after the counters have been updated.
935 *
936 * If the counters have been updated by the second thread
937 * but the thread has not yet been removed from the list
938 * then the other branch will be executing which will
939 * block on tasklist_lock until the exit handling of the
940 * other task is finished.
941 *
942 * This also implies that the sighand->siglock cannot
943 * be held by another processor. So we can also
944 * skip acquiring that lock.
945 */
946 utime = cputime_add(current->signal->utime, current->utime);
947 stime = cputime_add(current->signal->utime, current->stime);
948 cutime = current->signal->cutime;
949 cstime = current->signal->cstime;
950 } else
951 #endif
952 {
953
954 /* Process with multiple threads */
955 struct task_struct *tsk = current;
956 struct task_struct *t;
957
958 read_lock(&tasklist_lock);
959 utime = tsk->signal->utime;
960 stime = tsk->signal->stime;
961 t = tsk;
962 do {
963 utime = cputime_add(utime, t->utime);
964 stime = cputime_add(stime, t->stime);
965 t = next_thread(t);
966 } while (t != tsk);
967
968 /*
969 * While we have tasklist_lock read-locked, no dying thread
970 * can be updating current->signal->[us]time. Instead,
971 * we got their counts included in the live thread loop.
972 * However, another thread can come in right now and
973 * do a wait call that updates current->signal->c[us]time.
974 * To make sure we always see that pair updated atomically,
975 * we take the siglock around fetching them.
976 */
977 spin_lock_irq(&tsk->sighand->siglock);
978 cutime = tsk->signal->cutime;
979 cstime = tsk->signal->cstime;
980 spin_unlock_irq(&tsk->sighand->siglock);
981 read_unlock(&tasklist_lock);
982 }
983 tmp.tms_utime = cputime_to_clock_t(utime);
984 tmp.tms_stime = cputime_to_clock_t(stime);
985 tmp.tms_cutime = cputime_to_clock_t(cutime);
986 tmp.tms_cstime = cputime_to_clock_t(cstime);
987 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
988 return -EFAULT;
989 }
990 return (long) jiffies_64_to_clock_t(get_jiffies_64());
991 }
992
993 /*
994 * This needs some heavy checking ...
995 * I just haven't the stomach for it. I also don't fully
996 * understand sessions/pgrp etc. Let somebody who does explain it.
997 *
998 * OK, I think I have the protection semantics right.... this is really
999 * only important on a multi-user system anyway, to make sure one user
1000 * can't send a signal to a process owned by another. -TYT, 12/12/91
1001 *
1002 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1003 * LBT 04.03.94
1004 */
1005
1006 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1007 {
1008 struct task_struct *p;
1009 int err = -EINVAL;
1010
1011 if (!pid)
1012 pid = current->pid;
1013 if (!pgid)
1014 pgid = pid;
1015 if (pgid < 0)
1016 return -EINVAL;
1017
1018 /* From this point forward we keep holding onto the tasklist lock
1019 * so that our parent does not change from under us. -DaveM
1020 */
1021 write_lock_irq(&tasklist_lock);
1022
1023 err = -ESRCH;
1024 p = find_task_by_pid(pid);
1025 if (!p)
1026 goto out;
1027
1028 err = -EINVAL;
1029 if (!thread_group_leader(p))
1030 goto out;
1031
1032 if (p->parent == current || p->real_parent == current) {
1033 err = -EPERM;
1034 if (p->signal->session != current->signal->session)
1035 goto out;
1036 err = -EACCES;
1037 if (p->did_exec)
1038 goto out;
1039 } else {
1040 err = -ESRCH;
1041 if (p != current)
1042 goto out;
1043 }
1044
1045 err = -EPERM;
1046 if (p->signal->leader)
1047 goto out;
1048
1049 if (pgid != pid) {
1050 struct task_struct *p;
1051
1052 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1053 if (p->signal->session == current->signal->session)
1054 goto ok_pgid;
1055 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1056 goto out;
1057 }
1058
1059 ok_pgid:
1060 err = security_task_setpgid(p, pgid);
1061 if (err)
1062 goto out;
1063
1064 if (process_group(p) != pgid) {
1065 detach_pid(p, PIDTYPE_PGID);
1066 p->signal->pgrp = pgid;
1067 attach_pid(p, PIDTYPE_PGID, pgid);
1068 }
1069
1070 err = 0;
1071 out:
1072 /* All paths lead to here, thus we are safe. -DaveM */
1073 write_unlock_irq(&tasklist_lock);
1074 return err;
1075 }
1076
1077 asmlinkage long sys_getpgid(pid_t pid)
1078 {
1079 if (!pid) {
1080 return process_group(current);
1081 } else {
1082 int retval;
1083 struct task_struct *p;
1084
1085 read_lock(&tasklist_lock);
1086 p = find_task_by_pid(pid);
1087
1088 retval = -ESRCH;
1089 if (p) {
1090 retval = security_task_getpgid(p);
1091 if (!retval)
1092 retval = process_group(p);
1093 }
1094 read_unlock(&tasklist_lock);
1095 return retval;
1096 }
1097 }
1098
1099 #ifdef __ARCH_WANT_SYS_GETPGRP
1100
1101 asmlinkage long sys_getpgrp(void)
1102 {
1103 /* SMP - assuming writes are word atomic this is fine */
1104 return process_group(current);
1105 }
1106
1107 #endif
1108
1109 asmlinkage long sys_getsid(pid_t pid)
1110 {
1111 if (!pid) {
1112 return current->signal->session;
1113 } else {
1114 int retval;
1115 struct task_struct *p;
1116
1117 read_lock(&tasklist_lock);
1118 p = find_task_by_pid(pid);
1119
1120 retval = -ESRCH;
1121 if(p) {
1122 retval = security_task_getsid(p);
1123 if (!retval)
1124 retval = p->signal->session;
1125 }
1126 read_unlock(&tasklist_lock);
1127 return retval;
1128 }
1129 }
1130
1131 asmlinkage long sys_setsid(void)
1132 {
1133 struct pid *pid;
1134 int err = -EPERM;
1135
1136 if (!thread_group_leader(current))
1137 return -EINVAL;
1138
1139 down(&tty_sem);
1140 write_lock_irq(&tasklist_lock);
1141
1142 pid = find_pid(PIDTYPE_PGID, current->pid);
1143 if (pid)
1144 goto out;
1145
1146 current->signal->leader = 1;
1147 __set_special_pids(current->pid, current->pid);
1148 current->signal->tty = NULL;
1149 current->signal->tty_old_pgrp = 0;
1150 err = process_group(current);
1151 out:
1152 write_unlock_irq(&tasklist_lock);
1153 up(&tty_sem);
1154 return err;
1155 }
1156
1157 /*
1158 * Supplementary group IDs
1159 */
1160
1161 /* init to 2 - one for init_task, one to ensure it is never freed */
1162 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1163
1164 struct group_info *groups_alloc(int gidsetsize)
1165 {
1166 struct group_info *group_info;
1167 int nblocks;
1168 int i;
1169
1170 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1171 /* Make sure we always allocate at least one indirect block pointer */
1172 nblocks = nblocks ? : 1;
1173 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1174 if (!group_info)
1175 return NULL;
1176 group_info->ngroups = gidsetsize;
1177 group_info->nblocks = nblocks;
1178 atomic_set(&group_info->usage, 1);
1179
1180 if (gidsetsize <= NGROUPS_SMALL) {
1181 group_info->blocks[0] = group_info->small_block;
1182 } else {
1183 for (i = 0; i < nblocks; i++) {
1184 gid_t *b;
1185 b = (void *)__get_free_page(GFP_USER);
1186 if (!b)
1187 goto out_undo_partial_alloc;
1188 group_info->blocks[i] = b;
1189 }
1190 }
1191 return group_info;
1192
1193 out_undo_partial_alloc:
1194 while (--i >= 0) {
1195 free_page((unsigned long)group_info->blocks[i]);
1196 }
1197 kfree(group_info);
1198 return NULL;
1199 }
1200
1201 EXPORT_SYMBOL(groups_alloc);
1202
1203 void groups_free(struct group_info *group_info)
1204 {
1205 if (group_info->blocks[0] != group_info->small_block) {
1206 int i;
1207 for (i = 0; i < group_info->nblocks; i++)
1208 free_page((unsigned long)group_info->blocks[i]);
1209 }
1210 kfree(group_info);
1211 }
1212
1213 EXPORT_SYMBOL(groups_free);
1214
1215 /* export the group_info to a user-space array */
1216 static int groups_to_user(gid_t __user *grouplist,
1217 struct group_info *group_info)
1218 {
1219 int i;
1220 int count = group_info->ngroups;
1221
1222 for (i = 0; i < group_info->nblocks; i++) {
1223 int cp_count = min(NGROUPS_PER_BLOCK, count);
1224 int off = i * NGROUPS_PER_BLOCK;
1225 int len = cp_count * sizeof(*grouplist);
1226
1227 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1228 return -EFAULT;
1229
1230 count -= cp_count;
1231 }
1232 return 0;
1233 }
1234
1235 /* fill a group_info from a user-space array - it must be allocated already */
1236 static int groups_from_user(struct group_info *group_info,
1237 gid_t __user *grouplist)
1238 {
1239 int i;
1240 int count = group_info->ngroups;
1241
1242 for (i = 0; i < group_info->nblocks; i++) {
1243 int cp_count = min(NGROUPS_PER_BLOCK, count);
1244 int off = i * NGROUPS_PER_BLOCK;
1245 int len = cp_count * sizeof(*grouplist);
1246
1247 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1248 return -EFAULT;
1249
1250 count -= cp_count;
1251 }
1252 return 0;
1253 }
1254
1255 /* a simple Shell sort */
1256 static void groups_sort(struct group_info *group_info)
1257 {
1258 int base, max, stride;
1259 int gidsetsize = group_info->ngroups;
1260
1261 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1262 ; /* nothing */
1263 stride /= 3;
1264
1265 while (stride) {
1266 max = gidsetsize - stride;
1267 for (base = 0; base < max; base++) {
1268 int left = base;
1269 int right = left + stride;
1270 gid_t tmp = GROUP_AT(group_info, right);
1271
1272 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1273 GROUP_AT(group_info, right) =
1274 GROUP_AT(group_info, left);
1275 right = left;
1276 left -= stride;
1277 }
1278 GROUP_AT(group_info, right) = tmp;
1279 }
1280 stride /= 3;
1281 }
1282 }
1283
1284 /* a simple bsearch */
1285 int groups_search(struct group_info *group_info, gid_t grp)
1286 {
1287 int left, right;
1288
1289 if (!group_info)
1290 return 0;
1291
1292 left = 0;
1293 right = group_info->ngroups;
1294 while (left < right) {
1295 int mid = (left+right)/2;
1296 int cmp = grp - GROUP_AT(group_info, mid);
1297 if (cmp > 0)
1298 left = mid + 1;
1299 else if (cmp < 0)
1300 right = mid;
1301 else
1302 return 1;
1303 }
1304 return 0;
1305 }
1306
1307 /* validate and set current->group_info */
1308 int set_current_groups(struct group_info *group_info)
1309 {
1310 int retval;
1311 struct group_info *old_info;
1312
1313 retval = security_task_setgroups(group_info);
1314 if (retval)
1315 return retval;
1316
1317 groups_sort(group_info);
1318 get_group_info(group_info);
1319
1320 task_lock(current);
1321 old_info = current->group_info;
1322 current->group_info = group_info;
1323 task_unlock(current);
1324
1325 put_group_info(old_info);
1326
1327 return 0;
1328 }
1329
1330 EXPORT_SYMBOL(set_current_groups);
1331
1332 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1333 {
1334 int i = 0;
1335
1336 /*
1337 * SMP: Nobody else can change our grouplist. Thus we are
1338 * safe.
1339 */
1340
1341 if (gidsetsize < 0)
1342 return -EINVAL;
1343
1344 /* no need to grab task_lock here; it cannot change */
1345 get_group_info(current->group_info);
1346 i = current->group_info->ngroups;
1347 if (gidsetsize) {
1348 if (i > gidsetsize) {
1349 i = -EINVAL;
1350 goto out;
1351 }
1352 if (groups_to_user(grouplist, current->group_info)) {
1353 i = -EFAULT;
1354 goto out;
1355 }
1356 }
1357 out:
1358 put_group_info(current->group_info);
1359 return i;
1360 }
1361
1362 /*
1363 * SMP: Our groups are copy-on-write. We can set them safely
1364 * without another task interfering.
1365 */
1366
1367 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1368 {
1369 struct group_info *group_info;
1370 int retval;
1371
1372 if (!capable(CAP_SETGID))
1373 return -EPERM;
1374 if ((unsigned)gidsetsize > NGROUPS_MAX)
1375 return -EINVAL;
1376
1377 group_info = groups_alloc(gidsetsize);
1378 if (!group_info)
1379 return -ENOMEM;
1380 retval = groups_from_user(group_info, grouplist);
1381 if (retval) {
1382 put_group_info(group_info);
1383 return retval;
1384 }
1385
1386 retval = set_current_groups(group_info);
1387 put_group_info(group_info);
1388
1389 return retval;
1390 }
1391
1392 /*
1393 * Check whether we're fsgid/egid or in the supplemental group..
1394 */
1395 int in_group_p(gid_t grp)
1396 {
1397 int retval = 1;
1398 if (grp != current->fsgid) {
1399 get_group_info(current->group_info);
1400 retval = groups_search(current->group_info, grp);
1401 put_group_info(current->group_info);
1402 }
1403 return retval;
1404 }
1405
1406 EXPORT_SYMBOL(in_group_p);
1407
1408 int in_egroup_p(gid_t grp)
1409 {
1410 int retval = 1;
1411 if (grp != current->egid) {
1412 get_group_info(current->group_info);
1413 retval = groups_search(current->group_info, grp);
1414 put_group_info(current->group_info);
1415 }
1416 return retval;
1417 }
1418
1419 EXPORT_SYMBOL(in_egroup_p);
1420
1421 DECLARE_RWSEM(uts_sem);
1422
1423 EXPORT_SYMBOL(uts_sem);
1424
1425 asmlinkage long sys_newuname(struct new_utsname __user * name)
1426 {
1427 int errno = 0;
1428
1429 down_read(&uts_sem);
1430 if (copy_to_user(name,&system_utsname,sizeof *name))
1431 errno = -EFAULT;
1432 up_read(&uts_sem);
1433 return errno;
1434 }
1435
1436 asmlinkage long sys_sethostname(char __user *name, int len)
1437 {
1438 int errno;
1439 char tmp[__NEW_UTS_LEN];
1440
1441 if (!capable(CAP_SYS_ADMIN))
1442 return -EPERM;
1443 if (len < 0 || len > __NEW_UTS_LEN)
1444 return -EINVAL;
1445 down_write(&uts_sem);
1446 errno = -EFAULT;
1447 if (!copy_from_user(tmp, name, len)) {
1448 memcpy(system_utsname.nodename, tmp, len);
1449 system_utsname.nodename[len] = 0;
1450 errno = 0;
1451 }
1452 up_write(&uts_sem);
1453 return errno;
1454 }
1455
1456 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1457
1458 asmlinkage long sys_gethostname(char __user *name, int len)
1459 {
1460 int i, errno;
1461
1462 if (len < 0)
1463 return -EINVAL;
1464 down_read(&uts_sem);
1465 i = 1 + strlen(system_utsname.nodename);
1466 if (i > len)
1467 i = len;
1468 errno = 0;
1469 if (copy_to_user(name, system_utsname.nodename, i))
1470 errno = -EFAULT;
1471 up_read(&uts_sem);
1472 return errno;
1473 }
1474
1475 #endif
1476
1477 /*
1478 * Only setdomainname; getdomainname can be implemented by calling
1479 * uname()
1480 */
1481 asmlinkage long sys_setdomainname(char __user *name, int len)
1482 {
1483 int errno;
1484 char tmp[__NEW_UTS_LEN];
1485
1486 if (!capable(CAP_SYS_ADMIN))
1487 return -EPERM;
1488 if (len < 0 || len > __NEW_UTS_LEN)
1489 return -EINVAL;
1490
1491 down_write(&uts_sem);
1492 errno = -EFAULT;
1493 if (!copy_from_user(tmp, name, len)) {
1494 memcpy(system_utsname.domainname, tmp, len);
1495 system_utsname.domainname[len] = 0;
1496 errno = 0;
1497 }
1498 up_write(&uts_sem);
1499 return errno;
1500 }
1501
1502 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1503 {
1504 if (resource >= RLIM_NLIMITS)
1505 return -EINVAL;
1506 else {
1507 struct rlimit value;
1508 task_lock(current->group_leader);
1509 value = current->signal->rlim[resource];
1510 task_unlock(current->group_leader);
1511 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1512 }
1513 }
1514
1515 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1516
1517 /*
1518 * Back compatibility for getrlimit. Needed for some apps.
1519 */
1520
1521 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1522 {
1523 struct rlimit x;
1524 if (resource >= RLIM_NLIMITS)
1525 return -EINVAL;
1526
1527 task_lock(current->group_leader);
1528 x = current->signal->rlim[resource];
1529 task_unlock(current->group_leader);
1530 if(x.rlim_cur > 0x7FFFFFFF)
1531 x.rlim_cur = 0x7FFFFFFF;
1532 if(x.rlim_max > 0x7FFFFFFF)
1533 x.rlim_max = 0x7FFFFFFF;
1534 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1535 }
1536
1537 #endif
1538
1539 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1540 {
1541 struct rlimit new_rlim, *old_rlim;
1542 int retval;
1543
1544 if (resource >= RLIM_NLIMITS)
1545 return -EINVAL;
1546 if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1547 return -EFAULT;
1548 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1549 return -EINVAL;
1550 old_rlim = current->signal->rlim + resource;
1551 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1552 !capable(CAP_SYS_RESOURCE))
1553 return -EPERM;
1554 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1555 return -EPERM;
1556
1557 retval = security_task_setrlimit(resource, &new_rlim);
1558 if (retval)
1559 return retval;
1560
1561 task_lock(current->group_leader);
1562 *old_rlim = new_rlim;
1563 task_unlock(current->group_leader);
1564
1565 if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1566 (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1567 new_rlim.rlim_cur <= cputime_to_secs(
1568 current->signal->it_prof_expires))) {
1569 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1570 read_lock(&tasklist_lock);
1571 spin_lock_irq(&current->sighand->siglock);
1572 set_process_cpu_timer(current, CPUCLOCK_PROF,
1573 &cputime, NULL);
1574 spin_unlock_irq(&current->sighand->siglock);
1575 read_unlock(&tasklist_lock);
1576 }
1577
1578 return 0;
1579 }
1580
1581 /*
1582 * It would make sense to put struct rusage in the task_struct,
1583 * except that would make the task_struct be *really big*. After
1584 * task_struct gets moved into malloc'ed memory, it would
1585 * make sense to do this. It will make moving the rest of the information
1586 * a lot simpler! (Which we're not doing right now because we're not
1587 * measuring them yet).
1588 *
1589 * This expects to be called with tasklist_lock read-locked or better,
1590 * and the siglock not locked. It may momentarily take the siglock.
1591 *
1592 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1593 * races with threads incrementing their own counters. But since word
1594 * reads are atomic, we either get new values or old values and we don't
1595 * care which for the sums. We always take the siglock to protect reading
1596 * the c* fields from p->signal from races with exit.c updating those
1597 * fields when reaping, so a sample either gets all the additions of a
1598 * given child after it's reaped, or none so this sample is before reaping.
1599 */
1600
1601 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1602 {
1603 struct task_struct *t;
1604 unsigned long flags;
1605 cputime_t utime, stime;
1606
1607 memset((char *) r, 0, sizeof *r);
1608
1609 if (unlikely(!p->signal))
1610 return;
1611
1612 switch (who) {
1613 case RUSAGE_CHILDREN:
1614 spin_lock_irqsave(&p->sighand->siglock, flags);
1615 utime = p->signal->cutime;
1616 stime = p->signal->cstime;
1617 r->ru_nvcsw = p->signal->cnvcsw;
1618 r->ru_nivcsw = p->signal->cnivcsw;
1619 r->ru_minflt = p->signal->cmin_flt;
1620 r->ru_majflt = p->signal->cmaj_flt;
1621 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1622 cputime_to_timeval(utime, &r->ru_utime);
1623 cputime_to_timeval(stime, &r->ru_stime);
1624 break;
1625 case RUSAGE_SELF:
1626 spin_lock_irqsave(&p->sighand->siglock, flags);
1627 utime = stime = cputime_zero;
1628 goto sum_group;
1629 case RUSAGE_BOTH:
1630 spin_lock_irqsave(&p->sighand->siglock, flags);
1631 utime = p->signal->cutime;
1632 stime = p->signal->cstime;
1633 r->ru_nvcsw = p->signal->cnvcsw;
1634 r->ru_nivcsw = p->signal->cnivcsw;
1635 r->ru_minflt = p->signal->cmin_flt;
1636 r->ru_majflt = p->signal->cmaj_flt;
1637 sum_group:
1638 utime = cputime_add(utime, p->signal->utime);
1639 stime = cputime_add(stime, p->signal->stime);
1640 r->ru_nvcsw += p->signal->nvcsw;
1641 r->ru_nivcsw += p->signal->nivcsw;
1642 r->ru_minflt += p->signal->min_flt;
1643 r->ru_majflt += p->signal->maj_flt;
1644 t = p;
1645 do {
1646 utime = cputime_add(utime, t->utime);
1647 stime = cputime_add(stime, t->stime);
1648 r->ru_nvcsw += t->nvcsw;
1649 r->ru_nivcsw += t->nivcsw;
1650 r->ru_minflt += t->min_flt;
1651 r->ru_majflt += t->maj_flt;
1652 t = next_thread(t);
1653 } while (t != p);
1654 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1655 cputime_to_timeval(utime, &r->ru_utime);
1656 cputime_to_timeval(stime, &r->ru_stime);
1657 break;
1658 default:
1659 BUG();
1660 }
1661 }
1662
1663 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1664 {
1665 struct rusage r;
1666 read_lock(&tasklist_lock);
1667 k_getrusage(p, who, &r);
1668 read_unlock(&tasklist_lock);
1669 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1670 }
1671
1672 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1673 {
1674 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1675 return -EINVAL;
1676 return getrusage(current, who, ru);
1677 }
1678
1679 asmlinkage long sys_umask(int mask)
1680 {
1681 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1682 return mask;
1683 }
1684
1685 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1686 unsigned long arg4, unsigned long arg5)
1687 {
1688 long error;
1689 int sig;
1690
1691 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1692 if (error)
1693 return error;
1694
1695 switch (option) {
1696 case PR_SET_PDEATHSIG:
1697 sig = arg2;
1698 if (!valid_signal(sig)) {
1699 error = -EINVAL;
1700 break;
1701 }
1702 current->pdeath_signal = sig;
1703 break;
1704 case PR_GET_PDEATHSIG:
1705 error = put_user(current->pdeath_signal, (int __user *)arg2);
1706 break;
1707 case PR_GET_DUMPABLE:
1708 if (current->mm->dumpable)
1709 error = 1;
1710 break;
1711 case PR_SET_DUMPABLE:
1712 if (arg2 < 0 || arg2 > 2) {
1713 error = -EINVAL;
1714 break;
1715 }
1716 current->mm->dumpable = arg2;
1717 break;
1718
1719 case PR_SET_UNALIGN:
1720 error = SET_UNALIGN_CTL(current, arg2);
1721 break;
1722 case PR_GET_UNALIGN:
1723 error = GET_UNALIGN_CTL(current, arg2);
1724 break;
1725 case PR_SET_FPEMU:
1726 error = SET_FPEMU_CTL(current, arg2);
1727 break;
1728 case PR_GET_FPEMU:
1729 error = GET_FPEMU_CTL(current, arg2);
1730 break;
1731 case PR_SET_FPEXC:
1732 error = SET_FPEXC_CTL(current, arg2);
1733 break;
1734 case PR_GET_FPEXC:
1735 error = GET_FPEXC_CTL(current, arg2);
1736 break;
1737 case PR_GET_TIMING:
1738 error = PR_TIMING_STATISTICAL;
1739 break;
1740 case PR_SET_TIMING:
1741 if (arg2 == PR_TIMING_STATISTICAL)
1742 error = 0;
1743 else
1744 error = -EINVAL;
1745 break;
1746
1747 case PR_GET_KEEPCAPS:
1748 if (current->keep_capabilities)
1749 error = 1;
1750 break;
1751 case PR_SET_KEEPCAPS:
1752 if (arg2 != 0 && arg2 != 1) {
1753 error = -EINVAL;
1754 break;
1755 }
1756 current->keep_capabilities = arg2;
1757 break;
1758 case PR_SET_NAME: {
1759 struct task_struct *me = current;
1760 unsigned char ncomm[sizeof(me->comm)];
1761
1762 ncomm[sizeof(me->comm)-1] = 0;
1763 if (strncpy_from_user(ncomm, (char __user *)arg2,
1764 sizeof(me->comm)-1) < 0)
1765 return -EFAULT;
1766 set_task_comm(me, ncomm);
1767 return 0;
1768 }
1769 case PR_GET_NAME: {
1770 struct task_struct *me = current;
1771 unsigned char tcomm[sizeof(me->comm)];
1772
1773 get_task_comm(tcomm, me);
1774 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1775 return -EFAULT;
1776 return 0;
1777 }
1778 default:
1779 error = -EINVAL;
1780 break;
1781 }
1782 return error;
1783 }