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[mirror_ubuntu-bionic-kernel.git] / kernel / sys.c
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 void emergency_restart(void)
365 {
366 machine_emergency_restart();
367 }
368 EXPORT_SYMBOL_GPL(emergency_restart);
369
370 void kernel_restart(char *cmd)
371 {
372 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
373 system_state = SYSTEM_RESTART;
374 device_shutdown();
375 if (!cmd) {
376 printk(KERN_EMERG "Restarting system.\n");
377 } else {
378 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
379 }
380 printk(".\n");
381 machine_restart(cmd);
382 }
383 EXPORT_SYMBOL_GPL(kernel_restart);
384
385 void kernel_kexec(void)
386 {
387 #ifdef CONFIG_KEXEC
388 struct kimage *image;
389 image = xchg(&kexec_image, 0);
390 if (!image) {
391 return;
392 }
393 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
394 system_state = SYSTEM_RESTART;
395 device_suspend(PMSG_FREEZE);
396 device_shutdown();
397 printk(KERN_EMERG "Starting new kernel\n");
398 machine_shutdown();
399 machine_kexec(image);
400 #endif
401 }
402 EXPORT_SYMBOL_GPL(kernel_kexec);
403
404 void kernel_halt(void)
405 {
406 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
407 system_state = SYSTEM_HALT;
408 device_suspend(PMSG_SUSPEND);
409 device_shutdown();
410 printk(KERN_EMERG "System halted.\n");
411 machine_halt();
412 }
413 EXPORT_SYMBOL_GPL(kernel_halt);
414
415 void kernel_power_off(void)
416 {
417 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
418 system_state = SYSTEM_POWER_OFF;
419 device_suspend(PMSG_SUSPEND);
420 device_shutdown();
421 printk(KERN_EMERG "Power down.\n");
422 machine_power_off();
423 }
424 EXPORT_SYMBOL_GPL(kernel_power_off);
425
426 /*
427 * Reboot system call: for obvious reasons only root may call it,
428 * and even root needs to set up some magic numbers in the registers
429 * so that some mistake won't make this reboot the whole machine.
430 * You can also set the meaning of the ctrl-alt-del-key here.
431 *
432 * reboot doesn't sync: do that yourself before calling this.
433 */
434 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
435 {
436 char buffer[256];
437
438 /* We only trust the superuser with rebooting the system. */
439 if (!capable(CAP_SYS_BOOT))
440 return -EPERM;
441
442 /* For safety, we require "magic" arguments. */
443 if (magic1 != LINUX_REBOOT_MAGIC1 ||
444 (magic2 != LINUX_REBOOT_MAGIC2 &&
445 magic2 != LINUX_REBOOT_MAGIC2A &&
446 magic2 != LINUX_REBOOT_MAGIC2B &&
447 magic2 != LINUX_REBOOT_MAGIC2C))
448 return -EINVAL;
449
450 lock_kernel();
451 switch (cmd) {
452 case LINUX_REBOOT_CMD_RESTART:
453 kernel_restart(NULL);
454 break;
455
456 case LINUX_REBOOT_CMD_CAD_ON:
457 C_A_D = 1;
458 break;
459
460 case LINUX_REBOOT_CMD_CAD_OFF:
461 C_A_D = 0;
462 break;
463
464 case LINUX_REBOOT_CMD_HALT:
465 kernel_halt();
466 unlock_kernel();
467 do_exit(0);
468 break;
469
470 case LINUX_REBOOT_CMD_POWER_OFF:
471 kernel_power_off();
472 unlock_kernel();
473 do_exit(0);
474 break;
475
476 case LINUX_REBOOT_CMD_RESTART2:
477 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
478 unlock_kernel();
479 return -EFAULT;
480 }
481 buffer[sizeof(buffer) - 1] = '\0';
482
483 kernel_restart(buffer);
484 break;
485
486 case LINUX_REBOOT_CMD_KEXEC:
487 kernel_kexec();
488 unlock_kernel();
489 return -EINVAL;
490
491 #ifdef CONFIG_SOFTWARE_SUSPEND
492 case LINUX_REBOOT_CMD_SW_SUSPEND:
493 {
494 int ret = software_suspend();
495 unlock_kernel();
496 return ret;
497 }
498 #endif
499
500 default:
501 unlock_kernel();
502 return -EINVAL;
503 }
504 unlock_kernel();
505 return 0;
506 }
507
508 static void deferred_cad(void *dummy)
509 {
510 kernel_restart(NULL);
511 }
512
513 /*
514 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
515 * As it's called within an interrupt, it may NOT sync: the only choice
516 * is whether to reboot at once, or just ignore the ctrl-alt-del.
517 */
518 void ctrl_alt_del(void)
519 {
520 static DECLARE_WORK(cad_work, deferred_cad, NULL);
521
522 if (C_A_D)
523 schedule_work(&cad_work);
524 else
525 kill_proc(cad_pid, SIGINT, 1);
526 }
527
528
529 /*
530 * Unprivileged users may change the real gid to the effective gid
531 * or vice versa. (BSD-style)
532 *
533 * If you set the real gid at all, or set the effective gid to a value not
534 * equal to the real gid, then the saved gid is set to the new effective gid.
535 *
536 * This makes it possible for a setgid program to completely drop its
537 * privileges, which is often a useful assertion to make when you are doing
538 * a security audit over a program.
539 *
540 * The general idea is that a program which uses just setregid() will be
541 * 100% compatible with BSD. A program which uses just setgid() will be
542 * 100% compatible with POSIX with saved IDs.
543 *
544 * SMP: There are not races, the GIDs are checked only by filesystem
545 * operations (as far as semantic preservation is concerned).
546 */
547 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
548 {
549 int old_rgid = current->gid;
550 int old_egid = current->egid;
551 int new_rgid = old_rgid;
552 int new_egid = old_egid;
553 int retval;
554
555 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
556 if (retval)
557 return retval;
558
559 if (rgid != (gid_t) -1) {
560 if ((old_rgid == rgid) ||
561 (current->egid==rgid) ||
562 capable(CAP_SETGID))
563 new_rgid = rgid;
564 else
565 return -EPERM;
566 }
567 if (egid != (gid_t) -1) {
568 if ((old_rgid == egid) ||
569 (current->egid == egid) ||
570 (current->sgid == egid) ||
571 capable(CAP_SETGID))
572 new_egid = egid;
573 else {
574 return -EPERM;
575 }
576 }
577 if (new_egid != old_egid)
578 {
579 current->mm->dumpable = suid_dumpable;
580 smp_wmb();
581 }
582 if (rgid != (gid_t) -1 ||
583 (egid != (gid_t) -1 && egid != old_rgid))
584 current->sgid = new_egid;
585 current->fsgid = new_egid;
586 current->egid = new_egid;
587 current->gid = new_rgid;
588 key_fsgid_changed(current);
589 return 0;
590 }
591
592 /*
593 * setgid() is implemented like SysV w/ SAVED_IDS
594 *
595 * SMP: Same implicit races as above.
596 */
597 asmlinkage long sys_setgid(gid_t gid)
598 {
599 int old_egid = current->egid;
600 int retval;
601
602 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
603 if (retval)
604 return retval;
605
606 if (capable(CAP_SETGID))
607 {
608 if(old_egid != gid)
609 {
610 current->mm->dumpable = suid_dumpable;
611 smp_wmb();
612 }
613 current->gid = current->egid = current->sgid = current->fsgid = gid;
614 }
615 else if ((gid == current->gid) || (gid == current->sgid))
616 {
617 if(old_egid != gid)
618 {
619 current->mm->dumpable = suid_dumpable;
620 smp_wmb();
621 }
622 current->egid = current->fsgid = gid;
623 }
624 else
625 return -EPERM;
626
627 key_fsgid_changed(current);
628 return 0;
629 }
630
631 static int set_user(uid_t new_ruid, int dumpclear)
632 {
633 struct user_struct *new_user;
634
635 new_user = alloc_uid(new_ruid);
636 if (!new_user)
637 return -EAGAIN;
638
639 if (atomic_read(&new_user->processes) >=
640 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
641 new_user != &root_user) {
642 free_uid(new_user);
643 return -EAGAIN;
644 }
645
646 switch_uid(new_user);
647
648 if(dumpclear)
649 {
650 current->mm->dumpable = suid_dumpable;
651 smp_wmb();
652 }
653 current->uid = new_ruid;
654 return 0;
655 }
656
657 /*
658 * Unprivileged users may change the real uid to the effective uid
659 * or vice versa. (BSD-style)
660 *
661 * If you set the real uid at all, or set the effective uid to a value not
662 * equal to the real uid, then the saved uid is set to the new effective uid.
663 *
664 * This makes it possible for a setuid program to completely drop its
665 * privileges, which is often a useful assertion to make when you are doing
666 * a security audit over a program.
667 *
668 * The general idea is that a program which uses just setreuid() will be
669 * 100% compatible with BSD. A program which uses just setuid() will be
670 * 100% compatible with POSIX with saved IDs.
671 */
672 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
673 {
674 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
675 int retval;
676
677 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
678 if (retval)
679 return retval;
680
681 new_ruid = old_ruid = current->uid;
682 new_euid = old_euid = current->euid;
683 old_suid = current->suid;
684
685 if (ruid != (uid_t) -1) {
686 new_ruid = ruid;
687 if ((old_ruid != ruid) &&
688 (current->euid != ruid) &&
689 !capable(CAP_SETUID))
690 return -EPERM;
691 }
692
693 if (euid != (uid_t) -1) {
694 new_euid = euid;
695 if ((old_ruid != euid) &&
696 (current->euid != euid) &&
697 (current->suid != euid) &&
698 !capable(CAP_SETUID))
699 return -EPERM;
700 }
701
702 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
703 return -EAGAIN;
704
705 if (new_euid != old_euid)
706 {
707 current->mm->dumpable = suid_dumpable;
708 smp_wmb();
709 }
710 current->fsuid = current->euid = new_euid;
711 if (ruid != (uid_t) -1 ||
712 (euid != (uid_t) -1 && euid != old_ruid))
713 current->suid = current->euid;
714 current->fsuid = current->euid;
715
716 key_fsuid_changed(current);
717
718 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
719 }
720
721
722
723 /*
724 * setuid() is implemented like SysV with SAVED_IDS
725 *
726 * Note that SAVED_ID's is deficient in that a setuid root program
727 * like sendmail, for example, cannot set its uid to be a normal
728 * user and then switch back, because if you're root, setuid() sets
729 * the saved uid too. If you don't like this, blame the bright people
730 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
731 * will allow a root program to temporarily drop privileges and be able to
732 * regain them by swapping the real and effective uid.
733 */
734 asmlinkage long sys_setuid(uid_t uid)
735 {
736 int old_euid = current->euid;
737 int old_ruid, old_suid, new_ruid, new_suid;
738 int retval;
739
740 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
741 if (retval)
742 return retval;
743
744 old_ruid = new_ruid = current->uid;
745 old_suid = current->suid;
746 new_suid = old_suid;
747
748 if (capable(CAP_SETUID)) {
749 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
750 return -EAGAIN;
751 new_suid = uid;
752 } else if ((uid != current->uid) && (uid != new_suid))
753 return -EPERM;
754
755 if (old_euid != uid)
756 {
757 current->mm->dumpable = suid_dumpable;
758 smp_wmb();
759 }
760 current->fsuid = current->euid = uid;
761 current->suid = new_suid;
762
763 key_fsuid_changed(current);
764
765 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
766 }
767
768
769 /*
770 * This function implements a generic ability to update ruid, euid,
771 * and suid. This allows you to implement the 4.4 compatible seteuid().
772 */
773 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
774 {
775 int old_ruid = current->uid;
776 int old_euid = current->euid;
777 int old_suid = current->suid;
778 int retval;
779
780 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
781 if (retval)
782 return retval;
783
784 if (!capable(CAP_SETUID)) {
785 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
786 (ruid != current->euid) && (ruid != current->suid))
787 return -EPERM;
788 if ((euid != (uid_t) -1) && (euid != current->uid) &&
789 (euid != current->euid) && (euid != current->suid))
790 return -EPERM;
791 if ((suid != (uid_t) -1) && (suid != current->uid) &&
792 (suid != current->euid) && (suid != current->suid))
793 return -EPERM;
794 }
795 if (ruid != (uid_t) -1) {
796 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
797 return -EAGAIN;
798 }
799 if (euid != (uid_t) -1) {
800 if (euid != current->euid)
801 {
802 current->mm->dumpable = suid_dumpable;
803 smp_wmb();
804 }
805 current->euid = euid;
806 }
807 current->fsuid = current->euid;
808 if (suid != (uid_t) -1)
809 current->suid = suid;
810
811 key_fsuid_changed(current);
812
813 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
814 }
815
816 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
817 {
818 int retval;
819
820 if (!(retval = put_user(current->uid, ruid)) &&
821 !(retval = put_user(current->euid, euid)))
822 retval = put_user(current->suid, suid);
823
824 return retval;
825 }
826
827 /*
828 * Same as above, but for rgid, egid, sgid.
829 */
830 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
831 {
832 int retval;
833
834 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
835 if (retval)
836 return retval;
837
838 if (!capable(CAP_SETGID)) {
839 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
840 (rgid != current->egid) && (rgid != current->sgid))
841 return -EPERM;
842 if ((egid != (gid_t) -1) && (egid != current->gid) &&
843 (egid != current->egid) && (egid != current->sgid))
844 return -EPERM;
845 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
846 (sgid != current->egid) && (sgid != current->sgid))
847 return -EPERM;
848 }
849 if (egid != (gid_t) -1) {
850 if (egid != current->egid)
851 {
852 current->mm->dumpable = suid_dumpable;
853 smp_wmb();
854 }
855 current->egid = egid;
856 }
857 current->fsgid = current->egid;
858 if (rgid != (gid_t) -1)
859 current->gid = rgid;
860 if (sgid != (gid_t) -1)
861 current->sgid = sgid;
862
863 key_fsgid_changed(current);
864 return 0;
865 }
866
867 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
868 {
869 int retval;
870
871 if (!(retval = put_user(current->gid, rgid)) &&
872 !(retval = put_user(current->egid, egid)))
873 retval = put_user(current->sgid, sgid);
874
875 return retval;
876 }
877
878
879 /*
880 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
881 * is used for "access()" and for the NFS daemon (letting nfsd stay at
882 * whatever uid it wants to). It normally shadows "euid", except when
883 * explicitly set by setfsuid() or for access..
884 */
885 asmlinkage long sys_setfsuid(uid_t uid)
886 {
887 int old_fsuid;
888
889 old_fsuid = current->fsuid;
890 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
891 return old_fsuid;
892
893 if (uid == current->uid || uid == current->euid ||
894 uid == current->suid || uid == current->fsuid ||
895 capable(CAP_SETUID))
896 {
897 if (uid != old_fsuid)
898 {
899 current->mm->dumpable = suid_dumpable;
900 smp_wmb();
901 }
902 current->fsuid = uid;
903 }
904
905 key_fsuid_changed(current);
906
907 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
908
909 return old_fsuid;
910 }
911
912 /*
913 * Samma på svenska..
914 */
915 asmlinkage long sys_setfsgid(gid_t gid)
916 {
917 int old_fsgid;
918
919 old_fsgid = current->fsgid;
920 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
921 return old_fsgid;
922
923 if (gid == current->gid || gid == current->egid ||
924 gid == current->sgid || gid == current->fsgid ||
925 capable(CAP_SETGID))
926 {
927 if (gid != old_fsgid)
928 {
929 current->mm->dumpable = suid_dumpable;
930 smp_wmb();
931 }
932 current->fsgid = gid;
933 key_fsgid_changed(current);
934 }
935 return old_fsgid;
936 }
937
938 asmlinkage long sys_times(struct tms __user * tbuf)
939 {
940 /*
941 * In the SMP world we might just be unlucky and have one of
942 * the times increment as we use it. Since the value is an
943 * atomically safe type this is just fine. Conceptually its
944 * as if the syscall took an instant longer to occur.
945 */
946 if (tbuf) {
947 struct tms tmp;
948 cputime_t utime, stime, cutime, cstime;
949
950 #ifdef CONFIG_SMP
951 if (thread_group_empty(current)) {
952 /*
953 * Single thread case without the use of any locks.
954 *
955 * We may race with release_task if two threads are
956 * executing. However, release task first adds up the
957 * counters (__exit_signal) before removing the task
958 * from the process tasklist (__unhash_process).
959 * __exit_signal also acquires and releases the
960 * siglock which results in the proper memory ordering
961 * so that the list modifications are always visible
962 * after the counters have been updated.
963 *
964 * If the counters have been updated by the second thread
965 * but the thread has not yet been removed from the list
966 * then the other branch will be executing which will
967 * block on tasklist_lock until the exit handling of the
968 * other task is finished.
969 *
970 * This also implies that the sighand->siglock cannot
971 * be held by another processor. So we can also
972 * skip acquiring that lock.
973 */
974 utime = cputime_add(current->signal->utime, current->utime);
975 stime = cputime_add(current->signal->utime, current->stime);
976 cutime = current->signal->cutime;
977 cstime = current->signal->cstime;
978 } else
979 #endif
980 {
981
982 /* Process with multiple threads */
983 struct task_struct *tsk = current;
984 struct task_struct *t;
985
986 read_lock(&tasklist_lock);
987 utime = tsk->signal->utime;
988 stime = tsk->signal->stime;
989 t = tsk;
990 do {
991 utime = cputime_add(utime, t->utime);
992 stime = cputime_add(stime, t->stime);
993 t = next_thread(t);
994 } while (t != tsk);
995
996 /*
997 * While we have tasklist_lock read-locked, no dying thread
998 * can be updating current->signal->[us]time. Instead,
999 * we got their counts included in the live thread loop.
1000 * However, another thread can come in right now and
1001 * do a wait call that updates current->signal->c[us]time.
1002 * To make sure we always see that pair updated atomically,
1003 * we take the siglock around fetching them.
1004 */
1005 spin_lock_irq(&tsk->sighand->siglock);
1006 cutime = tsk->signal->cutime;
1007 cstime = tsk->signal->cstime;
1008 spin_unlock_irq(&tsk->sighand->siglock);
1009 read_unlock(&tasklist_lock);
1010 }
1011 tmp.tms_utime = cputime_to_clock_t(utime);
1012 tmp.tms_stime = cputime_to_clock_t(stime);
1013 tmp.tms_cutime = cputime_to_clock_t(cutime);
1014 tmp.tms_cstime = cputime_to_clock_t(cstime);
1015 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1016 return -EFAULT;
1017 }
1018 return (long) jiffies_64_to_clock_t(get_jiffies_64());
1019 }
1020
1021 /*
1022 * This needs some heavy checking ...
1023 * I just haven't the stomach for it. I also don't fully
1024 * understand sessions/pgrp etc. Let somebody who does explain it.
1025 *
1026 * OK, I think I have the protection semantics right.... this is really
1027 * only important on a multi-user system anyway, to make sure one user
1028 * can't send a signal to a process owned by another. -TYT, 12/12/91
1029 *
1030 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1031 * LBT 04.03.94
1032 */
1033
1034 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1035 {
1036 struct task_struct *p;
1037 int err = -EINVAL;
1038
1039 if (!pid)
1040 pid = current->pid;
1041 if (!pgid)
1042 pgid = pid;
1043 if (pgid < 0)
1044 return -EINVAL;
1045
1046 /* From this point forward we keep holding onto the tasklist lock
1047 * so that our parent does not change from under us. -DaveM
1048 */
1049 write_lock_irq(&tasklist_lock);
1050
1051 err = -ESRCH;
1052 p = find_task_by_pid(pid);
1053 if (!p)
1054 goto out;
1055
1056 err = -EINVAL;
1057 if (!thread_group_leader(p))
1058 goto out;
1059
1060 if (p->parent == current || p->real_parent == current) {
1061 err = -EPERM;
1062 if (p->signal->session != current->signal->session)
1063 goto out;
1064 err = -EACCES;
1065 if (p->did_exec)
1066 goto out;
1067 } else {
1068 err = -ESRCH;
1069 if (p != current)
1070 goto out;
1071 }
1072
1073 err = -EPERM;
1074 if (p->signal->leader)
1075 goto out;
1076
1077 if (pgid != pid) {
1078 struct task_struct *p;
1079
1080 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1081 if (p->signal->session == current->signal->session)
1082 goto ok_pgid;
1083 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1084 goto out;
1085 }
1086
1087 ok_pgid:
1088 err = security_task_setpgid(p, pgid);
1089 if (err)
1090 goto out;
1091
1092 if (process_group(p) != pgid) {
1093 detach_pid(p, PIDTYPE_PGID);
1094 p->signal->pgrp = pgid;
1095 attach_pid(p, PIDTYPE_PGID, pgid);
1096 }
1097
1098 err = 0;
1099 out:
1100 /* All paths lead to here, thus we are safe. -DaveM */
1101 write_unlock_irq(&tasklist_lock);
1102 return err;
1103 }
1104
1105 asmlinkage long sys_getpgid(pid_t pid)
1106 {
1107 if (!pid) {
1108 return process_group(current);
1109 } else {
1110 int retval;
1111 struct task_struct *p;
1112
1113 read_lock(&tasklist_lock);
1114 p = find_task_by_pid(pid);
1115
1116 retval = -ESRCH;
1117 if (p) {
1118 retval = security_task_getpgid(p);
1119 if (!retval)
1120 retval = process_group(p);
1121 }
1122 read_unlock(&tasklist_lock);
1123 return retval;
1124 }
1125 }
1126
1127 #ifdef __ARCH_WANT_SYS_GETPGRP
1128
1129 asmlinkage long sys_getpgrp(void)
1130 {
1131 /* SMP - assuming writes are word atomic this is fine */
1132 return process_group(current);
1133 }
1134
1135 #endif
1136
1137 asmlinkage long sys_getsid(pid_t pid)
1138 {
1139 if (!pid) {
1140 return current->signal->session;
1141 } else {
1142 int retval;
1143 struct task_struct *p;
1144
1145 read_lock(&tasklist_lock);
1146 p = find_task_by_pid(pid);
1147
1148 retval = -ESRCH;
1149 if(p) {
1150 retval = security_task_getsid(p);
1151 if (!retval)
1152 retval = p->signal->session;
1153 }
1154 read_unlock(&tasklist_lock);
1155 return retval;
1156 }
1157 }
1158
1159 asmlinkage long sys_setsid(void)
1160 {
1161 struct pid *pid;
1162 int err = -EPERM;
1163
1164 if (!thread_group_leader(current))
1165 return -EINVAL;
1166
1167 down(&tty_sem);
1168 write_lock_irq(&tasklist_lock);
1169
1170 pid = find_pid(PIDTYPE_PGID, current->pid);
1171 if (pid)
1172 goto out;
1173
1174 current->signal->leader = 1;
1175 __set_special_pids(current->pid, current->pid);
1176 current->signal->tty = NULL;
1177 current->signal->tty_old_pgrp = 0;
1178 err = process_group(current);
1179 out:
1180 write_unlock_irq(&tasklist_lock);
1181 up(&tty_sem);
1182 return err;
1183 }
1184
1185 /*
1186 * Supplementary group IDs
1187 */
1188
1189 /* init to 2 - one for init_task, one to ensure it is never freed */
1190 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1191
1192 struct group_info *groups_alloc(int gidsetsize)
1193 {
1194 struct group_info *group_info;
1195 int nblocks;
1196 int i;
1197
1198 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1199 /* Make sure we always allocate at least one indirect block pointer */
1200 nblocks = nblocks ? : 1;
1201 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1202 if (!group_info)
1203 return NULL;
1204 group_info->ngroups = gidsetsize;
1205 group_info->nblocks = nblocks;
1206 atomic_set(&group_info->usage, 1);
1207
1208 if (gidsetsize <= NGROUPS_SMALL) {
1209 group_info->blocks[0] = group_info->small_block;
1210 } else {
1211 for (i = 0; i < nblocks; i++) {
1212 gid_t *b;
1213 b = (void *)__get_free_page(GFP_USER);
1214 if (!b)
1215 goto out_undo_partial_alloc;
1216 group_info->blocks[i] = b;
1217 }
1218 }
1219 return group_info;
1220
1221 out_undo_partial_alloc:
1222 while (--i >= 0) {
1223 free_page((unsigned long)group_info->blocks[i]);
1224 }
1225 kfree(group_info);
1226 return NULL;
1227 }
1228
1229 EXPORT_SYMBOL(groups_alloc);
1230
1231 void groups_free(struct group_info *group_info)
1232 {
1233 if (group_info->blocks[0] != group_info->small_block) {
1234 int i;
1235 for (i = 0; i < group_info->nblocks; i++)
1236 free_page((unsigned long)group_info->blocks[i]);
1237 }
1238 kfree(group_info);
1239 }
1240
1241 EXPORT_SYMBOL(groups_free);
1242
1243 /* export the group_info to a user-space array */
1244 static int groups_to_user(gid_t __user *grouplist,
1245 struct group_info *group_info)
1246 {
1247 int i;
1248 int count = group_info->ngroups;
1249
1250 for (i = 0; i < group_info->nblocks; i++) {
1251 int cp_count = min(NGROUPS_PER_BLOCK, count);
1252 int off = i * NGROUPS_PER_BLOCK;
1253 int len = cp_count * sizeof(*grouplist);
1254
1255 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1256 return -EFAULT;
1257
1258 count -= cp_count;
1259 }
1260 return 0;
1261 }
1262
1263 /* fill a group_info from a user-space array - it must be allocated already */
1264 static int groups_from_user(struct group_info *group_info,
1265 gid_t __user *grouplist)
1266 {
1267 int i;
1268 int count = group_info->ngroups;
1269
1270 for (i = 0; i < group_info->nblocks; i++) {
1271 int cp_count = min(NGROUPS_PER_BLOCK, count);
1272 int off = i * NGROUPS_PER_BLOCK;
1273 int len = cp_count * sizeof(*grouplist);
1274
1275 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1276 return -EFAULT;
1277
1278 count -= cp_count;
1279 }
1280 return 0;
1281 }
1282
1283 /* a simple Shell sort */
1284 static void groups_sort(struct group_info *group_info)
1285 {
1286 int base, max, stride;
1287 int gidsetsize = group_info->ngroups;
1288
1289 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1290 ; /* nothing */
1291 stride /= 3;
1292
1293 while (stride) {
1294 max = gidsetsize - stride;
1295 for (base = 0; base < max; base++) {
1296 int left = base;
1297 int right = left + stride;
1298 gid_t tmp = GROUP_AT(group_info, right);
1299
1300 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1301 GROUP_AT(group_info, right) =
1302 GROUP_AT(group_info, left);
1303 right = left;
1304 left -= stride;
1305 }
1306 GROUP_AT(group_info, right) = tmp;
1307 }
1308 stride /= 3;
1309 }
1310 }
1311
1312 /* a simple bsearch */
1313 int groups_search(struct group_info *group_info, gid_t grp)
1314 {
1315 int left, right;
1316
1317 if (!group_info)
1318 return 0;
1319
1320 left = 0;
1321 right = group_info->ngroups;
1322 while (left < right) {
1323 int mid = (left+right)/2;
1324 int cmp = grp - GROUP_AT(group_info, mid);
1325 if (cmp > 0)
1326 left = mid + 1;
1327 else if (cmp < 0)
1328 right = mid;
1329 else
1330 return 1;
1331 }
1332 return 0;
1333 }
1334
1335 /* validate and set current->group_info */
1336 int set_current_groups(struct group_info *group_info)
1337 {
1338 int retval;
1339 struct group_info *old_info;
1340
1341 retval = security_task_setgroups(group_info);
1342 if (retval)
1343 return retval;
1344
1345 groups_sort(group_info);
1346 get_group_info(group_info);
1347
1348 task_lock(current);
1349 old_info = current->group_info;
1350 current->group_info = group_info;
1351 task_unlock(current);
1352
1353 put_group_info(old_info);
1354
1355 return 0;
1356 }
1357
1358 EXPORT_SYMBOL(set_current_groups);
1359
1360 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1361 {
1362 int i = 0;
1363
1364 /*
1365 * SMP: Nobody else can change our grouplist. Thus we are
1366 * safe.
1367 */
1368
1369 if (gidsetsize < 0)
1370 return -EINVAL;
1371
1372 /* no need to grab task_lock here; it cannot change */
1373 get_group_info(current->group_info);
1374 i = current->group_info->ngroups;
1375 if (gidsetsize) {
1376 if (i > gidsetsize) {
1377 i = -EINVAL;
1378 goto out;
1379 }
1380 if (groups_to_user(grouplist, current->group_info)) {
1381 i = -EFAULT;
1382 goto out;
1383 }
1384 }
1385 out:
1386 put_group_info(current->group_info);
1387 return i;
1388 }
1389
1390 /*
1391 * SMP: Our groups are copy-on-write. We can set them safely
1392 * without another task interfering.
1393 */
1394
1395 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1396 {
1397 struct group_info *group_info;
1398 int retval;
1399
1400 if (!capable(CAP_SETGID))
1401 return -EPERM;
1402 if ((unsigned)gidsetsize > NGROUPS_MAX)
1403 return -EINVAL;
1404
1405 group_info = groups_alloc(gidsetsize);
1406 if (!group_info)
1407 return -ENOMEM;
1408 retval = groups_from_user(group_info, grouplist);
1409 if (retval) {
1410 put_group_info(group_info);
1411 return retval;
1412 }
1413
1414 retval = set_current_groups(group_info);
1415 put_group_info(group_info);
1416
1417 return retval;
1418 }
1419
1420 /*
1421 * Check whether we're fsgid/egid or in the supplemental group..
1422 */
1423 int in_group_p(gid_t grp)
1424 {
1425 int retval = 1;
1426 if (grp != current->fsgid) {
1427 get_group_info(current->group_info);
1428 retval = groups_search(current->group_info, grp);
1429 put_group_info(current->group_info);
1430 }
1431 return retval;
1432 }
1433
1434 EXPORT_SYMBOL(in_group_p);
1435
1436 int in_egroup_p(gid_t grp)
1437 {
1438 int retval = 1;
1439 if (grp != current->egid) {
1440 get_group_info(current->group_info);
1441 retval = groups_search(current->group_info, grp);
1442 put_group_info(current->group_info);
1443 }
1444 return retval;
1445 }
1446
1447 EXPORT_SYMBOL(in_egroup_p);
1448
1449 DECLARE_RWSEM(uts_sem);
1450
1451 EXPORT_SYMBOL(uts_sem);
1452
1453 asmlinkage long sys_newuname(struct new_utsname __user * name)
1454 {
1455 int errno = 0;
1456
1457 down_read(&uts_sem);
1458 if (copy_to_user(name,&system_utsname,sizeof *name))
1459 errno = -EFAULT;
1460 up_read(&uts_sem);
1461 return errno;
1462 }
1463
1464 asmlinkage long sys_sethostname(char __user *name, int len)
1465 {
1466 int errno;
1467 char tmp[__NEW_UTS_LEN];
1468
1469 if (!capable(CAP_SYS_ADMIN))
1470 return -EPERM;
1471 if (len < 0 || len > __NEW_UTS_LEN)
1472 return -EINVAL;
1473 down_write(&uts_sem);
1474 errno = -EFAULT;
1475 if (!copy_from_user(tmp, name, len)) {
1476 memcpy(system_utsname.nodename, tmp, len);
1477 system_utsname.nodename[len] = 0;
1478 errno = 0;
1479 }
1480 up_write(&uts_sem);
1481 return errno;
1482 }
1483
1484 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1485
1486 asmlinkage long sys_gethostname(char __user *name, int len)
1487 {
1488 int i, errno;
1489
1490 if (len < 0)
1491 return -EINVAL;
1492 down_read(&uts_sem);
1493 i = 1 + strlen(system_utsname.nodename);
1494 if (i > len)
1495 i = len;
1496 errno = 0;
1497 if (copy_to_user(name, system_utsname.nodename, i))
1498 errno = -EFAULT;
1499 up_read(&uts_sem);
1500 return errno;
1501 }
1502
1503 #endif
1504
1505 /*
1506 * Only setdomainname; getdomainname can be implemented by calling
1507 * uname()
1508 */
1509 asmlinkage long sys_setdomainname(char __user *name, int len)
1510 {
1511 int errno;
1512 char tmp[__NEW_UTS_LEN];
1513
1514 if (!capable(CAP_SYS_ADMIN))
1515 return -EPERM;
1516 if (len < 0 || len > __NEW_UTS_LEN)
1517 return -EINVAL;
1518
1519 down_write(&uts_sem);
1520 errno = -EFAULT;
1521 if (!copy_from_user(tmp, name, len)) {
1522 memcpy(system_utsname.domainname, tmp, len);
1523 system_utsname.domainname[len] = 0;
1524 errno = 0;
1525 }
1526 up_write(&uts_sem);
1527 return errno;
1528 }
1529
1530 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1531 {
1532 if (resource >= RLIM_NLIMITS)
1533 return -EINVAL;
1534 else {
1535 struct rlimit value;
1536 task_lock(current->group_leader);
1537 value = current->signal->rlim[resource];
1538 task_unlock(current->group_leader);
1539 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1540 }
1541 }
1542
1543 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1544
1545 /*
1546 * Back compatibility for getrlimit. Needed for some apps.
1547 */
1548
1549 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1550 {
1551 struct rlimit x;
1552 if (resource >= RLIM_NLIMITS)
1553 return -EINVAL;
1554
1555 task_lock(current->group_leader);
1556 x = current->signal->rlim[resource];
1557 task_unlock(current->group_leader);
1558 if(x.rlim_cur > 0x7FFFFFFF)
1559 x.rlim_cur = 0x7FFFFFFF;
1560 if(x.rlim_max > 0x7FFFFFFF)
1561 x.rlim_max = 0x7FFFFFFF;
1562 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1563 }
1564
1565 #endif
1566
1567 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1568 {
1569 struct rlimit new_rlim, *old_rlim;
1570 int retval;
1571
1572 if (resource >= RLIM_NLIMITS)
1573 return -EINVAL;
1574 if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1575 return -EFAULT;
1576 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1577 return -EINVAL;
1578 old_rlim = current->signal->rlim + resource;
1579 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1580 !capable(CAP_SYS_RESOURCE))
1581 return -EPERM;
1582 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1583 return -EPERM;
1584
1585 retval = security_task_setrlimit(resource, &new_rlim);
1586 if (retval)
1587 return retval;
1588
1589 task_lock(current->group_leader);
1590 *old_rlim = new_rlim;
1591 task_unlock(current->group_leader);
1592
1593 if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1594 (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1595 new_rlim.rlim_cur <= cputime_to_secs(
1596 current->signal->it_prof_expires))) {
1597 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1598 read_lock(&tasklist_lock);
1599 spin_lock_irq(&current->sighand->siglock);
1600 set_process_cpu_timer(current, CPUCLOCK_PROF,
1601 &cputime, NULL);
1602 spin_unlock_irq(&current->sighand->siglock);
1603 read_unlock(&tasklist_lock);
1604 }
1605
1606 return 0;
1607 }
1608
1609 /*
1610 * It would make sense to put struct rusage in the task_struct,
1611 * except that would make the task_struct be *really big*. After
1612 * task_struct gets moved into malloc'ed memory, it would
1613 * make sense to do this. It will make moving the rest of the information
1614 * a lot simpler! (Which we're not doing right now because we're not
1615 * measuring them yet).
1616 *
1617 * This expects to be called with tasklist_lock read-locked or better,
1618 * and the siglock not locked. It may momentarily take the siglock.
1619 *
1620 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1621 * races with threads incrementing their own counters. But since word
1622 * reads are atomic, we either get new values or old values and we don't
1623 * care which for the sums. We always take the siglock to protect reading
1624 * the c* fields from p->signal from races with exit.c updating those
1625 * fields when reaping, so a sample either gets all the additions of a
1626 * given child after it's reaped, or none so this sample is before reaping.
1627 */
1628
1629 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1630 {
1631 struct task_struct *t;
1632 unsigned long flags;
1633 cputime_t utime, stime;
1634
1635 memset((char *) r, 0, sizeof *r);
1636
1637 if (unlikely(!p->signal))
1638 return;
1639
1640 switch (who) {
1641 case RUSAGE_CHILDREN:
1642 spin_lock_irqsave(&p->sighand->siglock, flags);
1643 utime = p->signal->cutime;
1644 stime = p->signal->cstime;
1645 r->ru_nvcsw = p->signal->cnvcsw;
1646 r->ru_nivcsw = p->signal->cnivcsw;
1647 r->ru_minflt = p->signal->cmin_flt;
1648 r->ru_majflt = p->signal->cmaj_flt;
1649 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1650 cputime_to_timeval(utime, &r->ru_utime);
1651 cputime_to_timeval(stime, &r->ru_stime);
1652 break;
1653 case RUSAGE_SELF:
1654 spin_lock_irqsave(&p->sighand->siglock, flags);
1655 utime = stime = cputime_zero;
1656 goto sum_group;
1657 case RUSAGE_BOTH:
1658 spin_lock_irqsave(&p->sighand->siglock, flags);
1659 utime = p->signal->cutime;
1660 stime = p->signal->cstime;
1661 r->ru_nvcsw = p->signal->cnvcsw;
1662 r->ru_nivcsw = p->signal->cnivcsw;
1663 r->ru_minflt = p->signal->cmin_flt;
1664 r->ru_majflt = p->signal->cmaj_flt;
1665 sum_group:
1666 utime = cputime_add(utime, p->signal->utime);
1667 stime = cputime_add(stime, p->signal->stime);
1668 r->ru_nvcsw += p->signal->nvcsw;
1669 r->ru_nivcsw += p->signal->nivcsw;
1670 r->ru_minflt += p->signal->min_flt;
1671 r->ru_majflt += p->signal->maj_flt;
1672 t = p;
1673 do {
1674 utime = cputime_add(utime, t->utime);
1675 stime = cputime_add(stime, t->stime);
1676 r->ru_nvcsw += t->nvcsw;
1677 r->ru_nivcsw += t->nivcsw;
1678 r->ru_minflt += t->min_flt;
1679 r->ru_majflt += t->maj_flt;
1680 t = next_thread(t);
1681 } while (t != p);
1682 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1683 cputime_to_timeval(utime, &r->ru_utime);
1684 cputime_to_timeval(stime, &r->ru_stime);
1685 break;
1686 default:
1687 BUG();
1688 }
1689 }
1690
1691 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1692 {
1693 struct rusage r;
1694 read_lock(&tasklist_lock);
1695 k_getrusage(p, who, &r);
1696 read_unlock(&tasklist_lock);
1697 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1698 }
1699
1700 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1701 {
1702 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1703 return -EINVAL;
1704 return getrusage(current, who, ru);
1705 }
1706
1707 asmlinkage long sys_umask(int mask)
1708 {
1709 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1710 return mask;
1711 }
1712
1713 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1714 unsigned long arg4, unsigned long arg5)
1715 {
1716 long error;
1717 int sig;
1718
1719 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1720 if (error)
1721 return error;
1722
1723 switch (option) {
1724 case PR_SET_PDEATHSIG:
1725 sig = arg2;
1726 if (!valid_signal(sig)) {
1727 error = -EINVAL;
1728 break;
1729 }
1730 current->pdeath_signal = sig;
1731 break;
1732 case PR_GET_PDEATHSIG:
1733 error = put_user(current->pdeath_signal, (int __user *)arg2);
1734 break;
1735 case PR_GET_DUMPABLE:
1736 if (current->mm->dumpable)
1737 error = 1;
1738 break;
1739 case PR_SET_DUMPABLE:
1740 if (arg2 < 0 || arg2 > 2) {
1741 error = -EINVAL;
1742 break;
1743 }
1744 current->mm->dumpable = arg2;
1745 break;
1746
1747 case PR_SET_UNALIGN:
1748 error = SET_UNALIGN_CTL(current, arg2);
1749 break;
1750 case PR_GET_UNALIGN:
1751 error = GET_UNALIGN_CTL(current, arg2);
1752 break;
1753 case PR_SET_FPEMU:
1754 error = SET_FPEMU_CTL(current, arg2);
1755 break;
1756 case PR_GET_FPEMU:
1757 error = GET_FPEMU_CTL(current, arg2);
1758 break;
1759 case PR_SET_FPEXC:
1760 error = SET_FPEXC_CTL(current, arg2);
1761 break;
1762 case PR_GET_FPEXC:
1763 error = GET_FPEXC_CTL(current, arg2);
1764 break;
1765 case PR_GET_TIMING:
1766 error = PR_TIMING_STATISTICAL;
1767 break;
1768 case PR_SET_TIMING:
1769 if (arg2 == PR_TIMING_STATISTICAL)
1770 error = 0;
1771 else
1772 error = -EINVAL;
1773 break;
1774
1775 case PR_GET_KEEPCAPS:
1776 if (current->keep_capabilities)
1777 error = 1;
1778 break;
1779 case PR_SET_KEEPCAPS:
1780 if (arg2 != 0 && arg2 != 1) {
1781 error = -EINVAL;
1782 break;
1783 }
1784 current->keep_capabilities = arg2;
1785 break;
1786 case PR_SET_NAME: {
1787 struct task_struct *me = current;
1788 unsigned char ncomm[sizeof(me->comm)];
1789
1790 ncomm[sizeof(me->comm)-1] = 0;
1791 if (strncpy_from_user(ncomm, (char __user *)arg2,
1792 sizeof(me->comm)-1) < 0)
1793 return -EFAULT;
1794 set_task_comm(me, ncomm);
1795 return 0;
1796 }
1797 case PR_GET_NAME: {
1798 struct task_struct *me = current;
1799 unsigned char tcomm[sizeof(me->comm)];
1800
1801 get_task_comm(tcomm, me);
1802 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1803 return -EFAULT;
1804 return 0;
1805 }
1806 default:
1807 error = -EINVAL;
1808 break;
1809 }
1810 return error;
1811 }
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