?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
kexec jump: remove duplication of kexec_restart_prepare()
[linux-2.6/x86.git] / kernel / sys.c
blob3dacb00a7f765977c92d896ca4556f93ff87616b
1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/smp_lock.h>
12 #include <linux/notifier.h>
13 #include <linux/reboot.h>
14 #include <linux/prctl.h>
15 #include <linux/highuid.h>
16 #include <linux/fs.h>
17 #include <linux/resource.h>
18 #include <linux/kernel.h>
19 #include <linux/kexec.h>
20 #include <linux/workqueue.h>
21 #include <linux/capability.h>
22 #include <linux/device.h>
23 #include <linux/key.h>
24 #include <linux/times.h>
25 #include <linux/posix-timers.h>
26 #include <linux/security.h>
27 #include <linux/dcookies.h>
28 #include <linux/suspend.h>
29 #include <linux/tty.h>
30 #include <linux/signal.h>
31 #include <linux/cn_proc.h>
32 #include <linux/getcpu.h>
33 #include <linux/task_io_accounting_ops.h>
34 #include <linux/seccomp.h>
35 #include <linux/cpu.h>
36
37 #include <linux/compat.h>
38 #include <linux/syscalls.h>
39 #include <linux/kprobes.h>
40 #include <linux/user_namespace.h>
41
42 #include <asm/uaccess.h>
43 #include <asm/io.h>
44 #include <asm/unistd.h>
45
46 #ifndef SET_UNALIGN_CTL
47 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
48 #endif
49 #ifndef GET_UNALIGN_CTL
50 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
51 #endif
52 #ifndef SET_FPEMU_CTL
53 # define SET_FPEMU_CTL(a,b) (-EINVAL)
54 #endif
55 #ifndef GET_FPEMU_CTL
56 # define GET_FPEMU_CTL(a,b) (-EINVAL)
57 #endif
58 #ifndef SET_FPEXC_CTL
59 # define SET_FPEXC_CTL(a,b) (-EINVAL)
60 #endif
61 #ifndef GET_FPEXC_CTL
62 # define GET_FPEXC_CTL(a,b) (-EINVAL)
63 #endif
64 #ifndef GET_ENDIAN
65 # define GET_ENDIAN(a,b) (-EINVAL)
66 #endif
67 #ifndef SET_ENDIAN
68 # define SET_ENDIAN(a,b) (-EINVAL)
69 #endif
70 #ifndef GET_TSC_CTL
71 # define GET_TSC_CTL(a) (-EINVAL)
72 #endif
73 #ifndef SET_TSC_CTL
74 # define SET_TSC_CTL(a) (-EINVAL)
75 #endif
76
77 /*
78 * this is where the system-wide overflow UID and GID are defined, for
79 * architectures that now have 32-bit UID/GID but didn't in the past
80 */
81
82 int overflowuid = DEFAULT_OVERFLOWUID;
83 int overflowgid = DEFAULT_OVERFLOWGID;
84
85 #ifdef CONFIG_UID16
86 EXPORT_SYMBOL(overflowuid);
87 EXPORT_SYMBOL(overflowgid);
88 #endif
89
90 /*
91 * the same as above, but for filesystems which can only store a 16-bit
92 * UID and GID. as such, this is needed on all architectures
93 */
94
95 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
96 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
97
98 EXPORT_SYMBOL(fs_overflowuid);
99 EXPORT_SYMBOL(fs_overflowgid);
100
101 /*
102 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
103 */
104
105 int C_A_D = 1;
106 struct pid *cad_pid;
107 EXPORT_SYMBOL(cad_pid);
108
109 /*
110 * If set, this is used for preparing the system to power off.
111 */
112
113 void (*pm_power_off_prepare)(void);
114
115 static int set_one_prio(struct task_struct *p, int niceval, int error)
116 {
117 int no_nice;
118
119 if (p->uid != current->euid &&
120 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
121 error = -EPERM;
122 goto out;
123 }
124 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
125 error = -EACCES;
126 goto out;
127 }
128 no_nice = security_task_setnice(p, niceval);
129 if (no_nice) {
130 error = no_nice;
131 goto out;
132 }
133 if (error == -ESRCH)
134 error = 0;
135 set_user_nice(p, niceval);
136 out:
137 return error;
138 }
139
140 asmlinkage long sys_setpriority(int which, int who, int niceval)
141 {
142 struct task_struct *g, *p;
143 struct user_struct *user;
144 int error = -EINVAL;
145 struct pid *pgrp;
146
147 if (which > PRIO_USER || which < PRIO_PROCESS)
148 goto out;
149
150 /* normalize: avoid signed division (rounding problems) */
151 error = -ESRCH;
152 if (niceval < -20)
153 niceval = -20;
154 if (niceval > 19)
155 niceval = 19;
156
157 read_lock(&tasklist_lock);
158 switch (which) {
159 case PRIO_PROCESS:
160 if (who)
161 p = find_task_by_vpid(who);
162 else
163 p = current;
164 if (p)
165 error = set_one_prio(p, niceval, error);
166 break;
167 case PRIO_PGRP:
168 if (who)
169 pgrp = find_vpid(who);
170 else
171 pgrp = task_pgrp(current);
172 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
175 break;
176 case PRIO_USER:
177 user = current->user;
178 if (!who)
179 who = current->uid;
180 else
181 if ((who != current->uid) && !(user = find_user(who)))
182 goto out_unlock; /* No processes for this user */
183
184 do_each_thread(g, p)
185 if (p->uid == who)
186 error = set_one_prio(p, niceval, error);
187 while_each_thread(g, p);
188 if (who != current->uid)
189 free_uid(user); /* For find_user() */
190 break;
191 }
192 out_unlock:
193 read_unlock(&tasklist_lock);
194 out:
195 return error;
196 }
197
198 /*
199 * Ugh. To avoid negative return values, "getpriority()" will
200 * not return the normal nice-value, but a negated value that
201 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
202 * to stay compatible.
203 */
204 asmlinkage long sys_getpriority(int which, int who)
205 {
206 struct task_struct *g, *p;
207 struct user_struct *user;
208 long niceval, retval = -ESRCH;
209 struct pid *pgrp;
210
211 if (which > PRIO_USER || which < PRIO_PROCESS)
212 return -EINVAL;
213
214 read_lock(&tasklist_lock);
215 switch (which) {
216 case PRIO_PROCESS:
217 if (who)
218 p = find_task_by_vpid(who);
219 else
220 p = current;
221 if (p) {
222 niceval = 20 - task_nice(p);
223 if (niceval > retval)
224 retval = niceval;
225 }
226 break;
227 case PRIO_PGRP:
228 if (who)
229 pgrp = find_vpid(who);
230 else
231 pgrp = task_pgrp(current);
232 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
235 retval = niceval;
236 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
237 break;
238 case PRIO_USER:
239 user = current->user;
240 if (!who)
241 who = current->uid;
242 else
243 if ((who != current->uid) && !(user = find_user(who)))
244 goto out_unlock; /* No processes for this user */
245
246 do_each_thread(g, p)
247 if (p->uid == who) {
248 niceval = 20 - task_nice(p);
249 if (niceval > retval)
250 retval = niceval;
251 }
252 while_each_thread(g, p);
253 if (who != current->uid)
254 free_uid(user); /* for find_user() */
255 break;
256 }
257 out_unlock:
258 read_unlock(&tasklist_lock);
259
260 return retval;
261 }
262
263 /**
264 * emergency_restart - reboot the system
265 *
266 * Without shutting down any hardware or taking any locks
267 * reboot the system. This is called when we know we are in
268 * trouble so this is our best effort to reboot. This is
269 * safe to call in interrupt context.
270 */
271 void emergency_restart(void)
272 {
273 machine_emergency_restart();
274 }
275 EXPORT_SYMBOL_GPL(emergency_restart);
276
277 void kernel_restart_prepare(char *cmd)
278 {
279 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
280 system_state = SYSTEM_RESTART;
281 device_shutdown();
282 sysdev_shutdown();
283 }
284
285 /**
286 * kernel_restart - reboot the system
287 * @cmd: pointer to buffer containing command to execute for restart
288 * or %NULL
289 *
290 * Shutdown everything and perform a clean reboot.
291 * This is not safe to call in interrupt context.
292 */
293 void kernel_restart(char *cmd)
294 {
295 kernel_restart_prepare(cmd);
296 if (!cmd)
297 printk(KERN_EMERG "Restarting system.\n");
298 else
299 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
300 machine_restart(cmd);
301 }
302 EXPORT_SYMBOL_GPL(kernel_restart);
303
304 static void kernel_shutdown_prepare(enum system_states state)
305 {
306 blocking_notifier_call_chain(&reboot_notifier_list,
307 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
308 system_state = state;
309 device_shutdown();
310 }
311 /**
312 * kernel_halt - halt the system
313 *
314 * Shutdown everything and perform a clean system halt.
315 */
316 void kernel_halt(void)
317 {
318 kernel_shutdown_prepare(SYSTEM_HALT);
319 sysdev_shutdown();
320 printk(KERN_EMERG "System halted.\n");
321 machine_halt();
322 }
323
324 EXPORT_SYMBOL_GPL(kernel_halt);
325
326 /**
327 * kernel_power_off - power_off the system
328 *
329 * Shutdown everything and perform a clean system power_off.
330 */
331 void kernel_power_off(void)
332 {
333 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
334 if (pm_power_off_prepare)
335 pm_power_off_prepare();
336 disable_nonboot_cpus();
337 sysdev_shutdown();
338 printk(KERN_EMERG "Power down.\n");
339 machine_power_off();
340 }
341 EXPORT_SYMBOL_GPL(kernel_power_off);
342 /*
343 * Reboot system call: for obvious reasons only root may call it,
344 * and even root needs to set up some magic numbers in the registers
345 * so that some mistake won't make this reboot the whole machine.
346 * You can also set the meaning of the ctrl-alt-del-key here.
347 *
348 * reboot doesn't sync: do that yourself before calling this.
349 */
350 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
351 {
352 char buffer[256];
353
354 /* We only trust the superuser with rebooting the system. */
355 if (!capable(CAP_SYS_BOOT))
356 return -EPERM;
357
358 /* For safety, we require "magic" arguments. */
359 if (magic1 != LINUX_REBOOT_MAGIC1 ||
360 (magic2 != LINUX_REBOOT_MAGIC2 &&
361 magic2 != LINUX_REBOOT_MAGIC2A &&
362 magic2 != LINUX_REBOOT_MAGIC2B &&
363 magic2 != LINUX_REBOOT_MAGIC2C))
364 return -EINVAL;
365
366 /* Instead of trying to make the power_off code look like
367 * halt when pm_power_off is not set do it the easy way.
368 */
369 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
370 cmd = LINUX_REBOOT_CMD_HALT;
371
372 lock_kernel();
373 switch (cmd) {
374 case LINUX_REBOOT_CMD_RESTART:
375 kernel_restart(NULL);
376 break;
377
378 case LINUX_REBOOT_CMD_CAD_ON:
379 C_A_D = 1;
380 break;
381
382 case LINUX_REBOOT_CMD_CAD_OFF:
383 C_A_D = 0;
384 break;
385
386 case LINUX_REBOOT_CMD_HALT:
387 kernel_halt();
388 unlock_kernel();
389 do_exit(0);
390 break;
391
392 case LINUX_REBOOT_CMD_POWER_OFF:
393 kernel_power_off();
394 unlock_kernel();
395 do_exit(0);
396 break;
397
398 case LINUX_REBOOT_CMD_RESTART2:
399 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
400 unlock_kernel();
401 return -EFAULT;
402 }
403 buffer[sizeof(buffer) - 1] = '\0';
404
405 kernel_restart(buffer);
406 break;
407
408 #ifdef CONFIG_KEXEC
409 case LINUX_REBOOT_CMD_KEXEC:
410 {
411 int ret;
412 ret = kernel_kexec();
413 unlock_kernel();
414 return ret;
415 }
416 #endif
417
418 #ifdef CONFIG_HIBERNATION
419 case LINUX_REBOOT_CMD_SW_SUSPEND:
420 {
421 int ret = hibernate();
422 unlock_kernel();
423 return ret;
424 }
425 #endif
426
427 default:
428 unlock_kernel();
429 return -EINVAL;
430 }
431 unlock_kernel();
432 return 0;
433 }
434
435 static void deferred_cad(struct work_struct *dummy)
436 {
437 kernel_restart(NULL);
438 }
439
440 /*
441 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
442 * As it's called within an interrupt, it may NOT sync: the only choice
443 * is whether to reboot at once, or just ignore the ctrl-alt-del.
444 */
445 void ctrl_alt_del(void)
446 {
447 static DECLARE_WORK(cad_work, deferred_cad);
448
449 if (C_A_D)
450 schedule_work(&cad_work);
451 else
452 kill_cad_pid(SIGINT, 1);
453 }
454
455 /*
456 * Unprivileged users may change the real gid to the effective gid
457 * or vice versa. (BSD-style)
458 *
459 * If you set the real gid at all, or set the effective gid to a value not
460 * equal to the real gid, then the saved gid is set to the new effective gid.
461 *
462 * This makes it possible for a setgid program to completely drop its
463 * privileges, which is often a useful assertion to make when you are doing
464 * a security audit over a program.
465 *
466 * The general idea is that a program which uses just setregid() will be
467 * 100% compatible with BSD. A program which uses just setgid() will be
468 * 100% compatible with POSIX with saved IDs.
469 *
470 * SMP: There are not races, the GIDs are checked only by filesystem
471 * operations (as far as semantic preservation is concerned).
472 */
473 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
474 {
475 int old_rgid = current->gid;
476 int old_egid = current->egid;
477 int new_rgid = old_rgid;
478 int new_egid = old_egid;
479 int retval;
480
481 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
482 if (retval)
483 return retval;
484
485 if (rgid != (gid_t) -1) {
486 if ((old_rgid == rgid) ||
487 (current->egid==rgid) ||
488 capable(CAP_SETGID))
489 new_rgid = rgid;
490 else
491 return -EPERM;
492 }
493 if (egid != (gid_t) -1) {
494 if ((old_rgid == egid) ||
495 (current->egid == egid) ||
496 (current->sgid == egid) ||
497 capable(CAP_SETGID))
498 new_egid = egid;
499 else
500 return -EPERM;
501 }
502 if (new_egid != old_egid) {
503 set_dumpable(current->mm, suid_dumpable);
504 smp_wmb();
505 }
506 if (rgid != (gid_t) -1 ||
507 (egid != (gid_t) -1 && egid != old_rgid))
508 current->sgid = new_egid;
509 current->fsgid = new_egid;
510 current->egid = new_egid;
511 current->gid = new_rgid;
512 key_fsgid_changed(current);
513 proc_id_connector(current, PROC_EVENT_GID);
514 return 0;
515 }
516
517 /*
518 * setgid() is implemented like SysV w/ SAVED_IDS
519 *
520 * SMP: Same implicit races as above.
521 */
522 asmlinkage long sys_setgid(gid_t gid)
523 {
524 int old_egid = current->egid;
525 int retval;
526
527 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
528 if (retval)
529 return retval;
530
531 if (capable(CAP_SETGID)) {
532 if (old_egid != gid) {
533 set_dumpable(current->mm, suid_dumpable);
534 smp_wmb();
535 }
536 current->gid = current->egid = current->sgid = current->fsgid = gid;
537 } else if ((gid == current->gid) || (gid == current->sgid)) {
538 if (old_egid != gid) {
539 set_dumpable(current->mm, suid_dumpable);
540 smp_wmb();
541 }
542 current->egid = current->fsgid = gid;
543 }
544 else
545 return -EPERM;
546
547 key_fsgid_changed(current);
548 proc_id_connector(current, PROC_EVENT_GID);
549 return 0;
550 }
551
552 static int set_user(uid_t new_ruid, int dumpclear)
553 {
554 struct user_struct *new_user;
555
556 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
557 if (!new_user)
558 return -EAGAIN;
559
560 if (atomic_read(&new_user->processes) >=
561 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
562 new_user != current->nsproxy->user_ns->root_user) {
563 free_uid(new_user);
564 return -EAGAIN;
565 }
566
567 switch_uid(new_user);
568
569 if (dumpclear) {
570 set_dumpable(current->mm, suid_dumpable);
571 smp_wmb();
572 }
573 current->uid = new_ruid;
574 return 0;
575 }
576
577 /*
578 * Unprivileged users may change the real uid to the effective uid
579 * or vice versa. (BSD-style)
580 *
581 * If you set the real uid at all, or set the effective uid to a value not
582 * equal to the real uid, then the saved uid is set to the new effective uid.
583 *
584 * This makes it possible for a setuid program to completely drop its
585 * privileges, which is often a useful assertion to make when you are doing
586 * a security audit over a program.
587 *
588 * The general idea is that a program which uses just setreuid() will be
589 * 100% compatible with BSD. A program which uses just setuid() will be
590 * 100% compatible with POSIX with saved IDs.
591 */
592 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
593 {
594 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
595 int retval;
596
597 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
598 if (retval)
599 return retval;
600
601 new_ruid = old_ruid = current->uid;
602 new_euid = old_euid = current->euid;
603 old_suid = current->suid;
604
605 if (ruid != (uid_t) -1) {
606 new_ruid = ruid;
607 if ((old_ruid != ruid) &&
608 (current->euid != ruid) &&
609 !capable(CAP_SETUID))
610 return -EPERM;
611 }
612
613 if (euid != (uid_t) -1) {
614 new_euid = euid;
615 if ((old_ruid != euid) &&
616 (current->euid != euid) &&
617 (current->suid != euid) &&
618 !capable(CAP_SETUID))
619 return -EPERM;
620 }
621
622 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
623 return -EAGAIN;
624
625 if (new_euid != old_euid) {
626 set_dumpable(current->mm, suid_dumpable);
627 smp_wmb();
628 }
629 current->fsuid = current->euid = new_euid;
630 if (ruid != (uid_t) -1 ||
631 (euid != (uid_t) -1 && euid != old_ruid))
632 current->suid = current->euid;
633 current->fsuid = current->euid;
634
635 key_fsuid_changed(current);
636 proc_id_connector(current, PROC_EVENT_UID);
637
638 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
639 }
640
641
642
643 /*
644 * setuid() is implemented like SysV with SAVED_IDS
645 *
646 * Note that SAVED_ID's is deficient in that a setuid root program
647 * like sendmail, for example, cannot set its uid to be a normal
648 * user and then switch back, because if you're root, setuid() sets
649 * the saved uid too. If you don't like this, blame the bright people
650 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
651 * will allow a root program to temporarily drop privileges and be able to
652 * regain them by swapping the real and effective uid.
653 */
654 asmlinkage long sys_setuid(uid_t uid)
655 {
656 int old_euid = current->euid;
657 int old_ruid, old_suid, new_suid;
658 int retval;
659
660 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
661 if (retval)
662 return retval;
663
664 old_ruid = current->uid;
665 old_suid = current->suid;
666 new_suid = old_suid;
667
668 if (capable(CAP_SETUID)) {
669 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
670 return -EAGAIN;
671 new_suid = uid;
672 } else if ((uid != current->uid) && (uid != new_suid))
673 return -EPERM;
674
675 if (old_euid != uid) {
676 set_dumpable(current->mm, suid_dumpable);
677 smp_wmb();
678 }
679 current->fsuid = current->euid = uid;
680 current->suid = new_suid;
681
682 key_fsuid_changed(current);
683 proc_id_connector(current, PROC_EVENT_UID);
684
685 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
686 }
687
688
689 /*
690 * This function implements a generic ability to update ruid, euid,
691 * and suid. This allows you to implement the 4.4 compatible seteuid().
692 */
693 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
694 {
695 int old_ruid = current->uid;
696 int old_euid = current->euid;
697 int old_suid = current->suid;
698 int retval;
699
700 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
701 if (retval)
702 return retval;
703
704 if (!capable(CAP_SETUID)) {
705 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
706 (ruid != current->euid) && (ruid != current->suid))
707 return -EPERM;
708 if ((euid != (uid_t) -1) && (euid != current->uid) &&
709 (euid != current->euid) && (euid != current->suid))
710 return -EPERM;
711 if ((suid != (uid_t) -1) && (suid != current->uid) &&
712 (suid != current->euid) && (suid != current->suid))
713 return -EPERM;
714 }
715 if (ruid != (uid_t) -1) {
716 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
717 return -EAGAIN;
718 }
719 if (euid != (uid_t) -1) {
720 if (euid != current->euid) {
721 set_dumpable(current->mm, suid_dumpable);
722 smp_wmb();
723 }
724 current->euid = euid;
725 }
726 current->fsuid = current->euid;
727 if (suid != (uid_t) -1)
728 current->suid = suid;
729
730 key_fsuid_changed(current);
731 proc_id_connector(current, PROC_EVENT_UID);
732
733 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
734 }
735
736 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
737 {
738 int retval;
739
740 if (!(retval = put_user(current->uid, ruid)) &&
741 !(retval = put_user(current->euid, euid)))
742 retval = put_user(current->suid, suid);
743
744 return retval;
745 }
746
747 /*
748 * Same as above, but for rgid, egid, sgid.
749 */
750 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
751 {
752 int retval;
753
754 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
755 if (retval)
756 return retval;
757
758 if (!capable(CAP_SETGID)) {
759 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
760 (rgid != current->egid) && (rgid != current->sgid))
761 return -EPERM;
762 if ((egid != (gid_t) -1) && (egid != current->gid) &&
763 (egid != current->egid) && (egid != current->sgid))
764 return -EPERM;
765 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
766 (sgid != current->egid) && (sgid != current->sgid))
767 return -EPERM;
768 }
769 if (egid != (gid_t) -1) {
770 if (egid != current->egid) {
771 set_dumpable(current->mm, suid_dumpable);
772 smp_wmb();
773 }
774 current->egid = egid;
775 }
776 current->fsgid = current->egid;
777 if (rgid != (gid_t) -1)
778 current->gid = rgid;
779 if (sgid != (gid_t) -1)
780 current->sgid = sgid;
781
782 key_fsgid_changed(current);
783 proc_id_connector(current, PROC_EVENT_GID);
784 return 0;
785 }
786
787 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
788 {
789 int retval;
790
791 if (!(retval = put_user(current->gid, rgid)) &&
792 !(retval = put_user(current->egid, egid)))
793 retval = put_user(current->sgid, sgid);
794
795 return retval;
796 }
797
798
799 /*
800 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
801 * is used for "access()" and for the NFS daemon (letting nfsd stay at
802 * whatever uid it wants to). It normally shadows "euid", except when
803 * explicitly set by setfsuid() or for access..
804 */
805 asmlinkage long sys_setfsuid(uid_t uid)
806 {
807 int old_fsuid;
808
809 old_fsuid = current->fsuid;
810 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
811 return old_fsuid;
812
813 if (uid == current->uid || uid == current->euid ||
814 uid == current->suid || uid == current->fsuid ||
815 capable(CAP_SETUID)) {
816 if (uid != old_fsuid) {
817 set_dumpable(current->mm, suid_dumpable);
818 smp_wmb();
819 }
820 current->fsuid = uid;
821 }
822
823 key_fsuid_changed(current);
824 proc_id_connector(current, PROC_EVENT_UID);
825
826 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
827
828 return old_fsuid;
829 }
830
831 /*
832 * Samma på svenska..
833 */
834 asmlinkage long sys_setfsgid(gid_t gid)
835 {
836 int old_fsgid;
837
838 old_fsgid = current->fsgid;
839 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
840 return old_fsgid;
841
842 if (gid == current->gid || gid == current->egid ||
843 gid == current->sgid || gid == current->fsgid ||
844 capable(CAP_SETGID)) {
845 if (gid != old_fsgid) {
846 set_dumpable(current->mm, suid_dumpable);
847 smp_wmb();
848 }
849 current->fsgid = gid;
850 key_fsgid_changed(current);
851 proc_id_connector(current, PROC_EVENT_GID);
852 }
853 return old_fsgid;
854 }
855
856 asmlinkage long sys_times(struct tms __user * tbuf)
857 {
858 /*
859 * In the SMP world we might just be unlucky and have one of
860 * the times increment as we use it. Since the value is an
861 * atomically safe type this is just fine. Conceptually its
862 * as if the syscall took an instant longer to occur.
863 */
864 if (tbuf) {
865 struct tms tmp;
866 struct task_struct *tsk = current;
867 struct task_struct *t;
868 cputime_t utime, stime, cutime, cstime;
869
870 spin_lock_irq(&tsk->sighand->siglock);
871 utime = tsk->signal->utime;
872 stime = tsk->signal->stime;
873 t = tsk;
874 do {
875 utime = cputime_add(utime, t->utime);
876 stime = cputime_add(stime, t->stime);
877 t = next_thread(t);
878 } while (t != tsk);
879
880 cutime = tsk->signal->cutime;
881 cstime = tsk->signal->cstime;
882 spin_unlock_irq(&tsk->sighand->siglock);
883
884 tmp.tms_utime = cputime_to_clock_t(utime);
885 tmp.tms_stime = cputime_to_clock_t(stime);
886 tmp.tms_cutime = cputime_to_clock_t(cutime);
887 tmp.tms_cstime = cputime_to_clock_t(cstime);
888 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
889 return -EFAULT;
890 }
891 return (long) jiffies_64_to_clock_t(get_jiffies_64());
892 }
893
894 /*
895 * This needs some heavy checking ...
896 * I just haven't the stomach for it. I also don't fully
897 * understand sessions/pgrp etc. Let somebody who does explain it.
898 *
899 * OK, I think I have the protection semantics right.... this is really
900 * only important on a multi-user system anyway, to make sure one user
901 * can't send a signal to a process owned by another. -TYT, 12/12/91
902 *
903 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
904 * LBT 04.03.94
905 */
906 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
907 {
908 struct task_struct *p;
909 struct task_struct *group_leader = current->group_leader;
910 struct pid *pgrp;
911 int err;
912
913 if (!pid)
914 pid = task_pid_vnr(group_leader);
915 if (!pgid)
916 pgid = pid;
917 if (pgid < 0)
918 return -EINVAL;
919
920 /* From this point forward we keep holding onto the tasklist lock
921 * so that our parent does not change from under us. -DaveM
922 */
923 write_lock_irq(&tasklist_lock);
924
925 err = -ESRCH;
926 p = find_task_by_vpid(pid);
927 if (!p)
928 goto out;
929
930 err = -EINVAL;
931 if (!thread_group_leader(p))
932 goto out;
933
934 if (same_thread_group(p->real_parent, group_leader)) {
935 err = -EPERM;
936 if (task_session(p) != task_session(group_leader))
937 goto out;
938 err = -EACCES;
939 if (p->did_exec)
940 goto out;
941 } else {
942 err = -ESRCH;
943 if (p != group_leader)
944 goto out;
945 }
946
947 err = -EPERM;
948 if (p->signal->leader)
949 goto out;
950
951 pgrp = task_pid(p);
952 if (pgid != pid) {
953 struct task_struct *g;
954
955 pgrp = find_vpid(pgid);
956 g = pid_task(pgrp, PIDTYPE_PGID);
957 if (!g || task_session(g) != task_session(group_leader))
958 goto out;
959 }
960
961 err = security_task_setpgid(p, pgid);
962 if (err)
963 goto out;
964
965 if (task_pgrp(p) != pgrp) {
966 change_pid(p, PIDTYPE_PGID, pgrp);
967 set_task_pgrp(p, pid_nr(pgrp));
968 }
969
970 err = 0;
971 out:
972 /* All paths lead to here, thus we are safe. -DaveM */
973 write_unlock_irq(&tasklist_lock);
974 return err;
975 }
976
977 asmlinkage long sys_getpgid(pid_t pid)
978 {
979 struct task_struct *p;
980 struct pid *grp;
981 int retval;
982
983 rcu_read_lock();
984 if (!pid)
985 grp = task_pgrp(current);
986 else {
987 retval = -ESRCH;
988 p = find_task_by_vpid(pid);
989 if (!p)
990 goto out;
991 grp = task_pgrp(p);
992 if (!grp)
993 goto out;
994
995 retval = security_task_getpgid(p);
996 if (retval)
997 goto out;
998 }
999 retval = pid_vnr(grp);
1000 out:
1001 rcu_read_unlock();
1002 return retval;
1003 }
1004
1005 #ifdef __ARCH_WANT_SYS_GETPGRP
1006
1007 asmlinkage long sys_getpgrp(void)
1008 {
1009 return sys_getpgid(0);
1010 }
1011
1012 #endif
1013
1014 asmlinkage long sys_getsid(pid_t pid)
1015 {
1016 struct task_struct *p;
1017 struct pid *sid;
1018 int retval;
1019
1020 rcu_read_lock();
1021 if (!pid)
1022 sid = task_session(current);
1023 else {
1024 retval = -ESRCH;
1025 p = find_task_by_vpid(pid);
1026 if (!p)
1027 goto out;
1028 sid = task_session(p);
1029 if (!sid)
1030 goto out;
1031
1032 retval = security_task_getsid(p);
1033 if (retval)
1034 goto out;
1035 }
1036 retval = pid_vnr(sid);
1037 out:
1038 rcu_read_unlock();
1039 return retval;
1040 }
1041
1042 asmlinkage long sys_setsid(void)
1043 {
1044 struct task_struct *group_leader = current->group_leader;
1045 struct pid *sid = task_pid(group_leader);
1046 pid_t session = pid_vnr(sid);
1047 int err = -EPERM;
1048
1049 write_lock_irq(&tasklist_lock);
1050 /* Fail if I am already a session leader */
1051 if (group_leader->signal->leader)
1052 goto out;
1053
1054 /* Fail if a process group id already exists that equals the
1055 * proposed session id.
1056 */
1057 if (pid_task(sid, PIDTYPE_PGID))
1058 goto out;
1059
1060 group_leader->signal->leader = 1;
1061 __set_special_pids(sid);
1062
1063 spin_lock(&group_leader->sighand->siglock);
1064 group_leader->signal->tty = NULL;
1065 spin_unlock(&group_leader->sighand->siglock);
1066
1067 err = session;
1068 out:
1069 write_unlock_irq(&tasklist_lock);
1070 return err;
1071 }
1072
1073 /*
1074 * Supplementary group IDs
1075 */
1076
1077 /* init to 2 - one for init_task, one to ensure it is never freed */
1078 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1079
1080 struct group_info *groups_alloc(int gidsetsize)
1081 {
1082 struct group_info *group_info;
1083 int nblocks;
1084 int i;
1085
1086 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1087 /* Make sure we always allocate at least one indirect block pointer */
1088 nblocks = nblocks ? : 1;
1089 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1090 if (!group_info)
1091 return NULL;
1092 group_info->ngroups = gidsetsize;
1093 group_info->nblocks = nblocks;
1094 atomic_set(&group_info->usage, 1);
1095
1096 if (gidsetsize <= NGROUPS_SMALL)
1097 group_info->blocks[0] = group_info->small_block;
1098 else {
1099 for (i = 0; i < nblocks; i++) {
1100 gid_t *b;
1101 b = (void *)__get_free_page(GFP_USER);
1102 if (!b)
1103 goto out_undo_partial_alloc;
1104 group_info->blocks[i] = b;
1105 }
1106 }
1107 return group_info;
1108
1109 out_undo_partial_alloc:
1110 while (--i >= 0) {
1111 free_page((unsigned long)group_info->blocks[i]);
1112 }
1113 kfree(group_info);
1114 return NULL;
1115 }
1116
1117 EXPORT_SYMBOL(groups_alloc);
1118
1119 void groups_free(struct group_info *group_info)
1120 {
1121 if (group_info->blocks[0] != group_info->small_block) {
1122 int i;
1123 for (i = 0; i < group_info->nblocks; i++)
1124 free_page((unsigned long)group_info->blocks[i]);
1125 }
1126 kfree(group_info);
1127 }
1128
1129 EXPORT_SYMBOL(groups_free);
1130
1131 /* export the group_info to a user-space array */
1132 static int groups_to_user(gid_t __user *grouplist,
1133 struct group_info *group_info)
1134 {
1135 int i;
1136 unsigned int count = group_info->ngroups;
1137
1138 for (i = 0; i < group_info->nblocks; i++) {
1139 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1140 unsigned int len = cp_count * sizeof(*grouplist);
1141
1142 if (copy_to_user(grouplist, group_info->blocks[i], len))
1143 return -EFAULT;
1144
1145 grouplist += NGROUPS_PER_BLOCK;
1146 count -= cp_count;
1147 }
1148 return 0;
1149 }
1150
1151 /* fill a group_info from a user-space array - it must be allocated already */
1152 static int groups_from_user(struct group_info *group_info,
1153 gid_t __user *grouplist)
1154 {
1155 int i;
1156 unsigned int count = group_info->ngroups;
1157
1158 for (i = 0; i < group_info->nblocks; i++) {
1159 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1160 unsigned int len = cp_count * sizeof(*grouplist);
1161
1162 if (copy_from_user(group_info->blocks[i], grouplist, len))
1163 return -EFAULT;
1164
1165 grouplist += NGROUPS_PER_BLOCK;
1166 count -= cp_count;
1167 }
1168 return 0;
1169 }
1170
1171 /* a simple Shell sort */
1172 static void groups_sort(struct group_info *group_info)
1173 {
1174 int base, max, stride;
1175 int gidsetsize = group_info->ngroups;
1176
1177 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1178 ; /* nothing */
1179 stride /= 3;
1180
1181 while (stride) {
1182 max = gidsetsize - stride;
1183 for (base = 0; base < max; base++) {
1184 int left = base;
1185 int right = left + stride;
1186 gid_t tmp = GROUP_AT(group_info, right);
1187
1188 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1189 GROUP_AT(group_info, right) =
1190 GROUP_AT(group_info, left);
1191 right = left;
1192 left -= stride;
1193 }
1194 GROUP_AT(group_info, right) = tmp;
1195 }
1196 stride /= 3;
1197 }
1198 }
1199
1200 /* a simple bsearch */
1201 int groups_search(struct group_info *group_info, gid_t grp)
1202 {
1203 unsigned int left, right;
1204
1205 if (!group_info)
1206 return 0;
1207
1208 left = 0;
1209 right = group_info->ngroups;
1210 while (left < right) {
1211 unsigned int mid = (left+right)/2;
1212 int cmp = grp - GROUP_AT(group_info, mid);
1213 if (cmp > 0)
1214 left = mid + 1;
1215 else if (cmp < 0)
1216 right = mid;
1217 else
1218 return 1;
1219 }
1220 return 0;
1221 }
1222
1223 /* validate and set current->group_info */
1224 int set_current_groups(struct group_info *group_info)
1225 {
1226 int retval;
1227 struct group_info *old_info;
1228
1229 retval = security_task_setgroups(group_info);
1230 if (retval)
1231 return retval;
1232
1233 groups_sort(group_info);
1234 get_group_info(group_info);
1235
1236 task_lock(current);
1237 old_info = current->group_info;
1238 current->group_info = group_info;
1239 task_unlock(current);
1240
1241 put_group_info(old_info);
1242
1243 return 0;
1244 }
1245
1246 EXPORT_SYMBOL(set_current_groups);
1247
1248 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1249 {
1250 int i = 0;
1251
1252 /*
1253 * SMP: Nobody else can change our grouplist. Thus we are
1254 * safe.
1255 */
1256
1257 if (gidsetsize < 0)
1258 return -EINVAL;
1259
1260 /* no need to grab task_lock here; it cannot change */
1261 i = current->group_info->ngroups;
1262 if (gidsetsize) {
1263 if (i > gidsetsize) {
1264 i = -EINVAL;
1265 goto out;
1266 }
1267 if (groups_to_user(grouplist, current->group_info)) {
1268 i = -EFAULT;
1269 goto out;
1270 }
1271 }
1272 out:
1273 return i;
1274 }
1275
1276 /*
1277 * SMP: Our groups are copy-on-write. We can set them safely
1278 * without another task interfering.
1279 */
1280
1281 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1282 {
1283 struct group_info *group_info;
1284 int retval;
1285
1286 if (!capable(CAP_SETGID))
1287 return -EPERM;
1288 if ((unsigned)gidsetsize > NGROUPS_MAX)
1289 return -EINVAL;
1290
1291 group_info = groups_alloc(gidsetsize);
1292 if (!group_info)
1293 return -ENOMEM;
1294 retval = groups_from_user(group_info, grouplist);
1295 if (retval) {
1296 put_group_info(group_info);
1297 return retval;
1298 }
1299
1300 retval = set_current_groups(group_info);
1301 put_group_info(group_info);
1302
1303 return retval;
1304 }
1305
1306 /*
1307 * Check whether we're fsgid/egid or in the supplemental group..
1308 */
1309 int in_group_p(gid_t grp)
1310 {
1311 int retval = 1;
1312 if (grp != current->fsgid)
1313 retval = groups_search(current->group_info, grp);
1314 return retval;
1315 }
1316
1317 EXPORT_SYMBOL(in_group_p);
1318
1319 int in_egroup_p(gid_t grp)
1320 {
1321 int retval = 1;
1322 if (grp != current->egid)
1323 retval = groups_search(current->group_info, grp);
1324 return retval;
1325 }
1326
1327 EXPORT_SYMBOL(in_egroup_p);
1328
1329 DECLARE_RWSEM(uts_sem);
1330
1331 asmlinkage long sys_newuname(struct new_utsname __user * name)
1332 {
1333 int errno = 0;
1334
1335 down_read(&uts_sem);
1336 if (copy_to_user(name, utsname(), sizeof *name))
1337 errno = -EFAULT;
1338 up_read(&uts_sem);
1339 return errno;
1340 }
1341
1342 asmlinkage long sys_sethostname(char __user *name, int len)
1343 {
1344 int errno;
1345 char tmp[__NEW_UTS_LEN];
1346
1347 if (!capable(CAP_SYS_ADMIN))
1348 return -EPERM;
1349 if (len < 0 || len > __NEW_UTS_LEN)
1350 return -EINVAL;
1351 down_write(&uts_sem);
1352 errno = -EFAULT;
1353 if (!copy_from_user(tmp, name, len)) {
1354 memcpy(utsname()->nodename, tmp, len);
1355 utsname()->nodename[len] = 0;
1356 errno = 0;
1357 }
1358 up_write(&uts_sem);
1359 return errno;
1360 }
1361
1362 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1363
1364 asmlinkage long sys_gethostname(char __user *name, int len)
1365 {
1366 int i, errno;
1367
1368 if (len < 0)
1369 return -EINVAL;
1370 down_read(&uts_sem);
1371 i = 1 + strlen(utsname()->nodename);
1372 if (i > len)
1373 i = len;
1374 errno = 0;
1375 if (copy_to_user(name, utsname()->nodename, i))
1376 errno = -EFAULT;
1377 up_read(&uts_sem);
1378 return errno;
1379 }
1380
1381 #endif
1382
1383 /*
1384 * Only setdomainname; getdomainname can be implemented by calling
1385 * uname()
1386 */
1387 asmlinkage long sys_setdomainname(char __user *name, int len)
1388 {
1389 int errno;
1390 char tmp[__NEW_UTS_LEN];
1391
1392 if (!capable(CAP_SYS_ADMIN))
1393 return -EPERM;
1394 if (len < 0 || len > __NEW_UTS_LEN)
1395 return -EINVAL;
1396
1397 down_write(&uts_sem);
1398 errno = -EFAULT;
1399 if (!copy_from_user(tmp, name, len)) {
1400 memcpy(utsname()->domainname, tmp, len);
1401 utsname()->domainname[len] = 0;
1402 errno = 0;
1403 }
1404 up_write(&uts_sem);
1405 return errno;
1406 }
1407
1408 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1409 {
1410 if (resource >= RLIM_NLIMITS)
1411 return -EINVAL;
1412 else {
1413 struct rlimit value;
1414 task_lock(current->group_leader);
1415 value = current->signal->rlim[resource];
1416 task_unlock(current->group_leader);
1417 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1418 }
1419 }
1420
1421 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1422
1423 /*
1424 * Back compatibility for getrlimit. Needed for some apps.
1425 */
1426
1427 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1428 {
1429 struct rlimit x;
1430 if (resource >= RLIM_NLIMITS)
1431 return -EINVAL;
1432
1433 task_lock(current->group_leader);
1434 x = current->signal->rlim[resource];
1435 task_unlock(current->group_leader);
1436 if (x.rlim_cur > 0x7FFFFFFF)
1437 x.rlim_cur = 0x7FFFFFFF;
1438 if (x.rlim_max > 0x7FFFFFFF)
1439 x.rlim_max = 0x7FFFFFFF;
1440 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1441 }
1442
1443 #endif
1444
1445 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1446 {
1447 struct rlimit new_rlim, *old_rlim;
1448 unsigned long it_prof_secs;
1449 int retval;
1450
1451 if (resource >= RLIM_NLIMITS)
1452 return -EINVAL;
1453 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1454 return -EFAULT;
1455 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1456 return -EINVAL;
1457 old_rlim = current->signal->rlim + resource;
1458 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1459 !capable(CAP_SYS_RESOURCE))
1460 return -EPERM;
1461 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1462 return -EPERM;
1463
1464 retval = security_task_setrlimit(resource, &new_rlim);
1465 if (retval)
1466 return retval;
1467
1468 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1469 /*
1470 * The caller is asking for an immediate RLIMIT_CPU
1471 * expiry. But we use the zero value to mean "it was
1472 * never set". So let's cheat and make it one second
1473 * instead
1474 */
1475 new_rlim.rlim_cur = 1;
1476 }
1477
1478 task_lock(current->group_leader);
1479 *old_rlim = new_rlim;
1480 task_unlock(current->group_leader);
1481
1482 if (resource != RLIMIT_CPU)
1483 goto out;
1484
1485 /*
1486 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1487 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1488 * very long-standing error, and fixing it now risks breakage of
1489 * applications, so we live with it
1490 */
1491 if (new_rlim.rlim_cur == RLIM_INFINITY)
1492 goto out;
1493
1494 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1495 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1496 unsigned long rlim_cur = new_rlim.rlim_cur;
1497 cputime_t cputime;
1498
1499 cputime = secs_to_cputime(rlim_cur);
1500 read_lock(&tasklist_lock);
1501 spin_lock_irq(&current->sighand->siglock);
1502 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1503 spin_unlock_irq(&current->sighand->siglock);
1504 read_unlock(&tasklist_lock);
1505 }
1506 out:
1507 return 0;
1508 }
1509
1510 /*
1511 * It would make sense to put struct rusage in the task_struct,
1512 * except that would make the task_struct be *really big*. After
1513 * task_struct gets moved into malloc'ed memory, it would
1514 * make sense to do this. It will make moving the rest of the information
1515 * a lot simpler! (Which we're not doing right now because we're not
1516 * measuring them yet).
1517 *
1518 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1519 * races with threads incrementing their own counters. But since word
1520 * reads are atomic, we either get new values or old values and we don't
1521 * care which for the sums. We always take the siglock to protect reading
1522 * the c* fields from p->signal from races with exit.c updating those
1523 * fields when reaping, so a sample either gets all the additions of a
1524 * given child after it's reaped, or none so this sample is before reaping.
1525 *
1526 * Locking:
1527 * We need to take the siglock for CHILDEREN, SELF and BOTH
1528 * for the cases current multithreaded, non-current single threaded
1529 * non-current multithreaded. Thread traversal is now safe with
1530 * the siglock held.
1531 * Strictly speaking, we donot need to take the siglock if we are current and
1532 * single threaded, as no one else can take our signal_struct away, no one
1533 * else can reap the children to update signal->c* counters, and no one else
1534 * can race with the signal-> fields. If we do not take any lock, the
1535 * signal-> fields could be read out of order while another thread was just
1536 * exiting. So we should place a read memory barrier when we avoid the lock.
1537 * On the writer side, write memory barrier is implied in __exit_signal
1538 * as __exit_signal releases the siglock spinlock after updating the signal->
1539 * fields. But we don't do this yet to keep things simple.
1540 *
1541 */
1542
1543 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
1544 cputime_t *utimep, cputime_t *stimep)
1545 {
1546 *utimep = cputime_add(*utimep, t->utime);
1547 *stimep = cputime_add(*stimep, t->stime);
1548 r->ru_nvcsw += t->nvcsw;
1549 r->ru_nivcsw += t->nivcsw;
1550 r->ru_minflt += t->min_flt;
1551 r->ru_majflt += t->maj_flt;
1552 r->ru_inblock += task_io_get_inblock(t);
1553 r->ru_oublock += task_io_get_oublock(t);
1554 }
1555
1556 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1557 {
1558 struct task_struct *t;
1559 unsigned long flags;
1560 cputime_t utime, stime;
1561
1562 memset((char *) r, 0, sizeof *r);
1563 utime = stime = cputime_zero;
1564
1565 if (who == RUSAGE_THREAD) {
1566 accumulate_thread_rusage(p, r, &utime, &stime);
1567 goto out;
1568 }
1569
1570 if (!lock_task_sighand(p, &flags))
1571 return;
1572
1573 switch (who) {
1574 case RUSAGE_BOTH:
1575 case RUSAGE_CHILDREN:
1576 utime = p->signal->cutime;
1577 stime = p->signal->cstime;
1578 r->ru_nvcsw = p->signal->cnvcsw;
1579 r->ru_nivcsw = p->signal->cnivcsw;
1580 r->ru_minflt = p->signal->cmin_flt;
1581 r->ru_majflt = p->signal->cmaj_flt;
1582 r->ru_inblock = p->signal->cinblock;
1583 r->ru_oublock = p->signal->coublock;
1584
1585 if (who == RUSAGE_CHILDREN)
1586 break;
1587
1588 case RUSAGE_SELF:
1589 utime = cputime_add(utime, p->signal->utime);
1590 stime = cputime_add(stime, p->signal->stime);
1591 r->ru_nvcsw += p->signal->nvcsw;
1592 r->ru_nivcsw += p->signal->nivcsw;
1593 r->ru_minflt += p->signal->min_flt;
1594 r->ru_majflt += p->signal->maj_flt;
1595 r->ru_inblock += p->signal->inblock;
1596 r->ru_oublock += p->signal->oublock;
1597 t = p;
1598 do {
1599 accumulate_thread_rusage(t, r, &utime, &stime);
1600 t = next_thread(t);
1601 } while (t != p);
1602 break;
1603
1604 default:
1605 BUG();
1606 }
1607 unlock_task_sighand(p, &flags);
1608
1609 out:
1610 cputime_to_timeval(utime, &r->ru_utime);
1611 cputime_to_timeval(stime, &r->ru_stime);
1612 }
1613
1614 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1615 {
1616 struct rusage r;
1617 k_getrusage(p, who, &r);
1618 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1619 }
1620
1621 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1622 {
1623 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1624 who != RUSAGE_THREAD)
1625 return -EINVAL;
1626 return getrusage(current, who, ru);
1627 }
1628
1629 asmlinkage long sys_umask(int mask)
1630 {
1631 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1632 return mask;
1633 }
1634
1635 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1636 unsigned long arg4, unsigned long arg5)
1637 {
1638 long error = 0;
1639
1640 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1641 return error;
1642
1643 switch (option) {
1644 case PR_SET_PDEATHSIG:
1645 if (!valid_signal(arg2)) {
1646 error = -EINVAL;
1647 break;
1648 }
1649 current->pdeath_signal = arg2;
1650 break;
1651 case PR_GET_PDEATHSIG:
1652 error = put_user(current->pdeath_signal, (int __user *)arg2);
1653 break;
1654 case PR_GET_DUMPABLE:
1655 error = get_dumpable(current->mm);
1656 break;
1657 case PR_SET_DUMPABLE:
1658 if (arg2 < 0 || arg2 > 1) {
1659 error = -EINVAL;
1660 break;
1661 }
1662 set_dumpable(current->mm, arg2);
1663 break;
1664
1665 case PR_SET_UNALIGN:
1666 error = SET_UNALIGN_CTL(current, arg2);
1667 break;
1668 case PR_GET_UNALIGN:
1669 error = GET_UNALIGN_CTL(current, arg2);
1670 break;
1671 case PR_SET_FPEMU:
1672 error = SET_FPEMU_CTL(current, arg2);
1673 break;
1674 case PR_GET_FPEMU:
1675 error = GET_FPEMU_CTL(current, arg2);
1676 break;
1677 case PR_SET_FPEXC:
1678 error = SET_FPEXC_CTL(current, arg2);
1679 break;
1680 case PR_GET_FPEXC:
1681 error = GET_FPEXC_CTL(current, arg2);
1682 break;
1683 case PR_GET_TIMING:
1684 error = PR_TIMING_STATISTICAL;
1685 break;
1686 case PR_SET_TIMING:
1687 if (arg2 != PR_TIMING_STATISTICAL)
1688 error = -EINVAL;
1689 break;
1690
1691 case PR_SET_NAME: {
1692 struct task_struct *me = current;
1693 unsigned char ncomm[sizeof(me->comm)];
1694
1695 ncomm[sizeof(me->comm)-1] = 0;
1696 if (strncpy_from_user(ncomm, (char __user *)arg2,
1697 sizeof(me->comm)-1) < 0)
1698 return -EFAULT;
1699 set_task_comm(me, ncomm);
1700 return 0;
1701 }
1702 case PR_GET_NAME: {
1703 struct task_struct *me = current;
1704 unsigned char tcomm[sizeof(me->comm)];
1705
1706 get_task_comm(tcomm, me);
1707 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1708 return -EFAULT;
1709 return 0;
1710 }
1711 case PR_GET_ENDIAN:
1712 error = GET_ENDIAN(current, arg2);
1713 break;
1714 case PR_SET_ENDIAN:
1715 error = SET_ENDIAN(current, arg2);
1716 break;
1717
1718 case PR_GET_SECCOMP:
1719 error = prctl_get_seccomp();
1720 break;
1721 case PR_SET_SECCOMP:
1722 error = prctl_set_seccomp(arg2);
1723 break;
1724 case PR_GET_TSC:
1725 error = GET_TSC_CTL(arg2);
1726 break;
1727 case PR_SET_TSC:
1728 error = SET_TSC_CTL(arg2);
1729 break;
1730 default:
1731 error = -EINVAL;
1732 break;
1733 }
1734 return error;
1735 }
1736
1737 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1738 struct getcpu_cache __user *unused)
1739 {
1740 int err = 0;
1741 int cpu = raw_smp_processor_id();
1742 if (cpup)
1743 err |= put_user(cpu, cpup);
1744 if (nodep)
1745 err |= put_user(cpu_to_node(cpu), nodep);
1746 return err ? -EFAULT : 0;
1747 }
1748
1749 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1750
1751 static void argv_cleanup(char **argv, char **envp)
1752 {
1753 argv_free(argv);
1754 }
1755
1756 /**
1757 * orderly_poweroff - Trigger an orderly system poweroff
1758 * @force: force poweroff if command execution fails
1759 *
1760 * This may be called from any context to trigger a system shutdown.
1761 * If the orderly shutdown fails, it will force an immediate shutdown.
1762 */
1763 int orderly_poweroff(bool force)
1764 {
1765 int argc;
1766 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1767 static char *envp[] = {
1768 "HOME=/",
1769 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1770 NULL
1771 };
1772 int ret = -ENOMEM;
1773 struct subprocess_info *info;
1774
1775 if (argv == NULL) {
1776 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1777 __func__, poweroff_cmd);
1778 goto out;
1779 }
1780
1781 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1782 if (info == NULL) {
1783 argv_free(argv);
1784 goto out;
1785 }
1786
1787 call_usermodehelper_setcleanup(info, argv_cleanup);
1788
1789 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1790
1791 out:
1792 if (ret && force) {
1793 printk(KERN_WARNING "Failed to start orderly shutdown: "
1794 "forcing the issue\n");
1795
1796 /* I guess this should try to kick off some daemon to
1797 sync and poweroff asap. Or not even bother syncing
1798 if we're doing an emergency shutdown? */
1799 emergency_sync();
1800 kernel_power_off();
1801 }
1802
1803 return ret;
1804 }
1805 EXPORT_SYMBOL_GPL(orderly_poweroff);
x86 "subsystem" repository