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thinkpad-acpi: improve Kconfig help text
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / sys.c
blob5608c6615523462d6a91c542cf20dc87a7c6729a
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 SYSCALL_DEFINE3(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_thread(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_thread(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 SYSCALL_DEFINE2(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_thread(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
235 retval = niceval;
236 } while_each_pid_thread(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 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
351 void __user *, arg)
352 {
353 char buffer[256];
354
355 /* We only trust the superuser with rebooting the system. */
356 if (!capable(CAP_SYS_BOOT))
357 return -EPERM;
358
359 /* For safety, we require "magic" arguments. */
360 if (magic1 != LINUX_REBOOT_MAGIC1 ||
361 (magic2 != LINUX_REBOOT_MAGIC2 &&
362 magic2 != LINUX_REBOOT_MAGIC2A &&
363 magic2 != LINUX_REBOOT_MAGIC2B &&
364 magic2 != LINUX_REBOOT_MAGIC2C))
365 return -EINVAL;
366
367 /* Instead of trying to make the power_off code look like
368 * halt when pm_power_off is not set do it the easy way.
369 */
370 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
371 cmd = LINUX_REBOOT_CMD_HALT;
372
373 lock_kernel();
374 switch (cmd) {
375 case LINUX_REBOOT_CMD_RESTART:
376 kernel_restart(NULL);
377 break;
378
379 case LINUX_REBOOT_CMD_CAD_ON:
380 C_A_D = 1;
381 break;
382
383 case LINUX_REBOOT_CMD_CAD_OFF:
384 C_A_D = 0;
385 break;
386
387 case LINUX_REBOOT_CMD_HALT:
388 kernel_halt();
389 unlock_kernel();
390 do_exit(0);
391 break;
392
393 case LINUX_REBOOT_CMD_POWER_OFF:
394 kernel_power_off();
395 unlock_kernel();
396 do_exit(0);
397 break;
398
399 case LINUX_REBOOT_CMD_RESTART2:
400 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
401 unlock_kernel();
402 return -EFAULT;
403 }
404 buffer[sizeof(buffer) - 1] = '\0';
405
406 kernel_restart(buffer);
407 break;
408
409 #ifdef CONFIG_KEXEC
410 case LINUX_REBOOT_CMD_KEXEC:
411 {
412 int ret;
413 ret = kernel_kexec();
414 unlock_kernel();
415 return ret;
416 }
417 #endif
418
419 #ifdef CONFIG_HIBERNATION
420 case LINUX_REBOOT_CMD_SW_SUSPEND:
421 {
422 int ret = hibernate();
423 unlock_kernel();
424 return ret;
425 }
426 #endif
427
428 default:
429 unlock_kernel();
430 return -EINVAL;
431 }
432 unlock_kernel();
433 return 0;
434 }
435
436 static void deferred_cad(struct work_struct *dummy)
437 {
438 kernel_restart(NULL);
439 }
440
441 /*
442 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
443 * As it's called within an interrupt, it may NOT sync: the only choice
444 * is whether to reboot at once, or just ignore the ctrl-alt-del.
445 */
446 void ctrl_alt_del(void)
447 {
448 static DECLARE_WORK(cad_work, deferred_cad);
449
450 if (C_A_D)
451 schedule_work(&cad_work);
452 else
453 kill_cad_pid(SIGINT, 1);
454 }
455
456 /*
457 * Unprivileged users may change the real gid to the effective gid
458 * or vice versa. (BSD-style)
459 *
460 * If you set the real gid at all, or set the effective gid to a value not
461 * equal to the real gid, then the saved gid is set to the new effective gid.
462 *
463 * This makes it possible for a setgid program to completely drop its
464 * privileges, which is often a useful assertion to make when you are doing
465 * a security audit over a program.
466 *
467 * The general idea is that a program which uses just setregid() will be
468 * 100% compatible with BSD. A program which uses just setgid() will be
469 * 100% compatible with POSIX with saved IDs.
470 *
471 * SMP: There are not races, the GIDs are checked only by filesystem
472 * operations (as far as semantic preservation is concerned).
473 */
474 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
475 {
476 int old_rgid = current->gid;
477 int old_egid = current->egid;
478 int new_rgid = old_rgid;
479 int new_egid = old_egid;
480 int retval;
481
482 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
483 if (retval)
484 return retval;
485
486 if (rgid != (gid_t) -1) {
487 if ((old_rgid == rgid) ||
488 (current->egid==rgid) ||
489 capable(CAP_SETGID))
490 new_rgid = rgid;
491 else
492 return -EPERM;
493 }
494 if (egid != (gid_t) -1) {
495 if ((old_rgid == egid) ||
496 (current->egid == egid) ||
497 (current->sgid == egid) ||
498 capable(CAP_SETGID))
499 new_egid = egid;
500 else
501 return -EPERM;
502 }
503 if (new_egid != old_egid) {
504 set_dumpable(current->mm, suid_dumpable);
505 smp_wmb();
506 }
507 if (rgid != (gid_t) -1 ||
508 (egid != (gid_t) -1 && egid != old_rgid))
509 current->sgid = new_egid;
510 current->fsgid = new_egid;
511 current->egid = new_egid;
512 current->gid = new_rgid;
513 key_fsgid_changed(current);
514 proc_id_connector(current, PROC_EVENT_GID);
515 return 0;
516 }
517
518 /*
519 * setgid() is implemented like SysV w/ SAVED_IDS
520 *
521 * SMP: Same implicit races as above.
522 */
523 SYSCALL_DEFINE1(setgid, gid_t, gid)
524 {
525 int old_egid = current->egid;
526 int retval;
527
528 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
529 if (retval)
530 return retval;
531
532 if (capable(CAP_SETGID)) {
533 if (old_egid != gid) {
534 set_dumpable(current->mm, suid_dumpable);
535 smp_wmb();
536 }
537 current->gid = current->egid = current->sgid = current->fsgid = gid;
538 } else if ((gid == current->gid) || (gid == current->sgid)) {
539 if (old_egid != gid) {
540 set_dumpable(current->mm, suid_dumpable);
541 smp_wmb();
542 }
543 current->egid = current->fsgid = gid;
544 }
545 else
546 return -EPERM;
547
548 key_fsgid_changed(current);
549 proc_id_connector(current, PROC_EVENT_GID);
550 return 0;
551 }
552
553 static int set_user(uid_t new_ruid, int dumpclear)
554 {
555 struct user_struct *new_user;
556
557 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
558 if (!new_user)
559 return -EAGAIN;
560
561 if (atomic_read(&new_user->processes) >=
562 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
563 new_user != current->nsproxy->user_ns->root_user) {
564 free_uid(new_user);
565 return -EAGAIN;
566 }
567
568 switch_uid(new_user);
569
570 if (dumpclear) {
571 set_dumpable(current->mm, suid_dumpable);
572 smp_wmb();
573 }
574 current->uid = new_ruid;
575 return 0;
576 }
577
578 /*
579 * Unprivileged users may change the real uid to the effective uid
580 * or vice versa. (BSD-style)
581 *
582 * If you set the real uid at all, or set the effective uid to a value not
583 * equal to the real uid, then the saved uid is set to the new effective uid.
584 *
585 * This makes it possible for a setuid program to completely drop its
586 * privileges, which is often a useful assertion to make when you are doing
587 * a security audit over a program.
588 *
589 * The general idea is that a program which uses just setreuid() will be
590 * 100% compatible with BSD. A program which uses just setuid() will be
591 * 100% compatible with POSIX with saved IDs.
592 */
593 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
594 {
595 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
596 int retval;
597
598 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
599 if (retval)
600 return retval;
601
602 new_ruid = old_ruid = current->uid;
603 new_euid = old_euid = current->euid;
604 old_suid = current->suid;
605
606 if (ruid != (uid_t) -1) {
607 new_ruid = ruid;
608 if ((old_ruid != ruid) &&
609 (current->euid != ruid) &&
610 !capable(CAP_SETUID))
611 return -EPERM;
612 }
613
614 if (euid != (uid_t) -1) {
615 new_euid = euid;
616 if ((old_ruid != euid) &&
617 (current->euid != euid) &&
618 (current->suid != euid) &&
619 !capable(CAP_SETUID))
620 return -EPERM;
621 }
622
623 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
624 return -EAGAIN;
625
626 if (new_euid != old_euid) {
627 set_dumpable(current->mm, suid_dumpable);
628 smp_wmb();
629 }
630 current->fsuid = current->euid = new_euid;
631 if (ruid != (uid_t) -1 ||
632 (euid != (uid_t) -1 && euid != old_ruid))
633 current->suid = current->euid;
634 current->fsuid = current->euid;
635
636 key_fsuid_changed(current);
637 proc_id_connector(current, PROC_EVENT_UID);
638
639 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
640 }
641
642
643
644 /*
645 * setuid() is implemented like SysV with SAVED_IDS
646 *
647 * Note that SAVED_ID's is deficient in that a setuid root program
648 * like sendmail, for example, cannot set its uid to be a normal
649 * user and then switch back, because if you're root, setuid() sets
650 * the saved uid too. If you don't like this, blame the bright people
651 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
652 * will allow a root program to temporarily drop privileges and be able to
653 * regain them by swapping the real and effective uid.
654 */
655 SYSCALL_DEFINE1(setuid, uid_t, uid)
656 {
657 int old_euid = current->euid;
658 int old_ruid, old_suid, new_suid;
659 int retval;
660
661 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
662 if (retval)
663 return retval;
664
665 old_ruid = current->uid;
666 old_suid = current->suid;
667 new_suid = old_suid;
668
669 if (capable(CAP_SETUID)) {
670 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
671 return -EAGAIN;
672 new_suid = uid;
673 } else if ((uid != current->uid) && (uid != new_suid))
674 return -EPERM;
675
676 if (old_euid != uid) {
677 set_dumpable(current->mm, suid_dumpable);
678 smp_wmb();
679 }
680 current->fsuid = current->euid = uid;
681 current->suid = new_suid;
682
683 key_fsuid_changed(current);
684 proc_id_connector(current, PROC_EVENT_UID);
685
686 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
687 }
688
689
690 /*
691 * This function implements a generic ability to update ruid, euid,
692 * and suid. This allows you to implement the 4.4 compatible seteuid().
693 */
694 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
695 {
696 int old_ruid = current->uid;
697 int old_euid = current->euid;
698 int old_suid = current->suid;
699 int retval;
700
701 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
702 if (retval)
703 return retval;
704
705 if (!capable(CAP_SETUID)) {
706 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
707 (ruid != current->euid) && (ruid != current->suid))
708 return -EPERM;
709 if ((euid != (uid_t) -1) && (euid != current->uid) &&
710 (euid != current->euid) && (euid != current->suid))
711 return -EPERM;
712 if ((suid != (uid_t) -1) && (suid != current->uid) &&
713 (suid != current->euid) && (suid != current->suid))
714 return -EPERM;
715 }
716 if (ruid != (uid_t) -1) {
717 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
718 return -EAGAIN;
719 }
720 if (euid != (uid_t) -1) {
721 if (euid != current->euid) {
722 set_dumpable(current->mm, suid_dumpable);
723 smp_wmb();
724 }
725 current->euid = euid;
726 }
727 current->fsuid = current->euid;
728 if (suid != (uid_t) -1)
729 current->suid = suid;
730
731 key_fsuid_changed(current);
732 proc_id_connector(current, PROC_EVENT_UID);
733
734 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
735 }
736
737 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
738 {
739 int retval;
740
741 if (!(retval = put_user(current->uid, ruid)) &&
742 !(retval = put_user(current->euid, euid)))
743 retval = put_user(current->suid, suid);
744
745 return retval;
746 }
747
748 /*
749 * Same as above, but for rgid, egid, sgid.
750 */
751 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
752 {
753 int retval;
754
755 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
756 if (retval)
757 return retval;
758
759 if (!capable(CAP_SETGID)) {
760 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
761 (rgid != current->egid) && (rgid != current->sgid))
762 return -EPERM;
763 if ((egid != (gid_t) -1) && (egid != current->gid) &&
764 (egid != current->egid) && (egid != current->sgid))
765 return -EPERM;
766 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
767 (sgid != current->egid) && (sgid != current->sgid))
768 return -EPERM;
769 }
770 if (egid != (gid_t) -1) {
771 if (egid != current->egid) {
772 set_dumpable(current->mm, suid_dumpable);
773 smp_wmb();
774 }
775 current->egid = egid;
776 }
777 current->fsgid = current->egid;
778 if (rgid != (gid_t) -1)
779 current->gid = rgid;
780 if (sgid != (gid_t) -1)
781 current->sgid = sgid;
782
783 key_fsgid_changed(current);
784 proc_id_connector(current, PROC_EVENT_GID);
785 return 0;
786 }
787
788 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
789 {
790 int retval;
791
792 if (!(retval = put_user(current->gid, rgid)) &&
793 !(retval = put_user(current->egid, egid)))
794 retval = put_user(current->sgid, sgid);
795
796 return retval;
797 }
798
799
800 /*
801 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
802 * is used for "access()" and for the NFS daemon (letting nfsd stay at
803 * whatever uid it wants to). It normally shadows "euid", except when
804 * explicitly set by setfsuid() or for access..
805 */
806 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
807 {
808 int old_fsuid;
809
810 old_fsuid = current->fsuid;
811 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
812 return old_fsuid;
813
814 if (uid == current->uid || uid == current->euid ||
815 uid == current->suid || uid == current->fsuid ||
816 capable(CAP_SETUID)) {
817 if (uid != old_fsuid) {
818 set_dumpable(current->mm, suid_dumpable);
819 smp_wmb();
820 }
821 current->fsuid = uid;
822 }
823
824 key_fsuid_changed(current);
825 proc_id_connector(current, PROC_EVENT_UID);
826
827 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
828
829 return old_fsuid;
830 }
831
832 /*
833 * Samma på svenska..
834 */
835 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
836 {
837 int old_fsgid;
838
839 old_fsgid = current->fsgid;
840 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
841 return old_fsgid;
842
843 if (gid == current->gid || gid == current->egid ||
844 gid == current->sgid || gid == current->fsgid ||
845 capable(CAP_SETGID)) {
846 if (gid != old_fsgid) {
847 set_dumpable(current->mm, suid_dumpable);
848 smp_wmb();
849 }
850 current->fsgid = gid;
851 key_fsgid_changed(current);
852 proc_id_connector(current, PROC_EVENT_GID);
853 }
854 return old_fsgid;
855 }
856
857 void do_sys_times(struct tms *tms)
858 {
859 struct task_cputime cputime;
860 cputime_t cutime, cstime;
861
862 spin_lock_irq(&current->sighand->siglock);
863 thread_group_cputime(current, &cputime);
864 cutime = current->signal->cutime;
865 cstime = current->signal->cstime;
866 spin_unlock_irq(&current->sighand->siglock);
867 tms->tms_utime = cputime_to_clock_t(cputime.utime);
868 tms->tms_stime = cputime_to_clock_t(cputime.stime);
869 tms->tms_cutime = cputime_to_clock_t(cutime);
870 tms->tms_cstime = cputime_to_clock_t(cstime);
871 }
872
873 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
874 {
875 if (tbuf) {
876 struct tms tmp;
877
878 do_sys_times(&tmp);
879 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
880 return -EFAULT;
881 }
882 return (long) jiffies_64_to_clock_t(get_jiffies_64());
883 }
884
885 /*
886 * This needs some heavy checking ...
887 * I just haven't the stomach for it. I also don't fully
888 * understand sessions/pgrp etc. Let somebody who does explain it.
889 *
890 * OK, I think I have the protection semantics right.... this is really
891 * only important on a multi-user system anyway, to make sure one user
892 * can't send a signal to a process owned by another. -TYT, 12/12/91
893 *
894 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
895 * LBT 04.03.94
896 */
897 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
898 {
899 struct task_struct *p;
900 struct task_struct *group_leader = current->group_leader;
901 struct pid *pgrp;
902 int err;
903
904 if (!pid)
905 pid = task_pid_vnr(group_leader);
906 if (!pgid)
907 pgid = pid;
908 if (pgid < 0)
909 return -EINVAL;
910
911 /* From this point forward we keep holding onto the tasklist lock
912 * so that our parent does not change from under us. -DaveM
913 */
914 write_lock_irq(&tasklist_lock);
915
916 err = -ESRCH;
917 p = find_task_by_vpid(pid);
918 if (!p)
919 goto out;
920
921 err = -EINVAL;
922 if (!thread_group_leader(p))
923 goto out;
924
925 if (same_thread_group(p->real_parent, group_leader)) {
926 err = -EPERM;
927 if (task_session(p) != task_session(group_leader))
928 goto out;
929 err = -EACCES;
930 if (p->did_exec)
931 goto out;
932 } else {
933 err = -ESRCH;
934 if (p != group_leader)
935 goto out;
936 }
937
938 err = -EPERM;
939 if (p->signal->leader)
940 goto out;
941
942 pgrp = task_pid(p);
943 if (pgid != pid) {
944 struct task_struct *g;
945
946 pgrp = find_vpid(pgid);
947 g = pid_task(pgrp, PIDTYPE_PGID);
948 if (!g || task_session(g) != task_session(group_leader))
949 goto out;
950 }
951
952 err = security_task_setpgid(p, pgid);
953 if (err)
954 goto out;
955
956 if (task_pgrp(p) != pgrp) {
957 change_pid(p, PIDTYPE_PGID, pgrp);
958 set_task_pgrp(p, pid_nr(pgrp));
959 }
960
961 err = 0;
962 out:
963 /* All paths lead to here, thus we are safe. -DaveM */
964 write_unlock_irq(&tasklist_lock);
965 return err;
966 }
967
968 SYSCALL_DEFINE1(getpgid, pid_t, pid)
969 {
970 struct task_struct *p;
971 struct pid *grp;
972 int retval;
973
974 rcu_read_lock();
975 if (!pid)
976 grp = task_pgrp(current);
977 else {
978 retval = -ESRCH;
979 p = find_task_by_vpid(pid);
980 if (!p)
981 goto out;
982 grp = task_pgrp(p);
983 if (!grp)
984 goto out;
985
986 retval = security_task_getpgid(p);
987 if (retval)
988 goto out;
989 }
990 retval = pid_vnr(grp);
991 out:
992 rcu_read_unlock();
993 return retval;
994 }
995
996 #ifdef __ARCH_WANT_SYS_GETPGRP
997
998 SYSCALL_DEFINE0(getpgrp)
999 {
1000 return sys_getpgid(0);
1001 }
1002
1003 #endif
1004
1005 SYSCALL_DEFINE1(getsid, pid_t, pid)
1006 {
1007 struct task_struct *p;
1008 struct pid *sid;
1009 int retval;
1010
1011 rcu_read_lock();
1012 if (!pid)
1013 sid = task_session(current);
1014 else {
1015 retval = -ESRCH;
1016 p = find_task_by_vpid(pid);
1017 if (!p)
1018 goto out;
1019 sid = task_session(p);
1020 if (!sid)
1021 goto out;
1022
1023 retval = security_task_getsid(p);
1024 if (retval)
1025 goto out;
1026 }
1027 retval = pid_vnr(sid);
1028 out:
1029 rcu_read_unlock();
1030 return retval;
1031 }
1032
1033 SYSCALL_DEFINE0(setsid)
1034 {
1035 struct task_struct *group_leader = current->group_leader;
1036 struct pid *sid = task_pid(group_leader);
1037 pid_t session = pid_vnr(sid);
1038 int err = -EPERM;
1039
1040 write_lock_irq(&tasklist_lock);
1041 /* Fail if I am already a session leader */
1042 if (group_leader->signal->leader)
1043 goto out;
1044
1045 /* Fail if a process group id already exists that equals the
1046 * proposed session id.
1047 */
1048 if (pid_task(sid, PIDTYPE_PGID))
1049 goto out;
1050
1051 group_leader->signal->leader = 1;
1052 __set_special_pids(sid);
1053
1054 proc_clear_tty(group_leader);
1055
1056 err = session;
1057 out:
1058 write_unlock_irq(&tasklist_lock);
1059 return err;
1060 }
1061
1062 /*
1063 * Supplementary group IDs
1064 */
1065
1066 /* init to 2 - one for init_task, one to ensure it is never freed */
1067 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1068
1069 struct group_info *groups_alloc(int gidsetsize)
1070 {
1071 struct group_info *group_info;
1072 int nblocks;
1073 int i;
1074
1075 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1076 /* Make sure we always allocate at least one indirect block pointer */
1077 nblocks = nblocks ? : 1;
1078 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1079 if (!group_info)
1080 return NULL;
1081 group_info->ngroups = gidsetsize;
1082 group_info->nblocks = nblocks;
1083 atomic_set(&group_info->usage, 1);
1084
1085 if (gidsetsize <= NGROUPS_SMALL)
1086 group_info->blocks[0] = group_info->small_block;
1087 else {
1088 for (i = 0; i < nblocks; i++) {
1089 gid_t *b;
1090 b = (void *)__get_free_page(GFP_USER);
1091 if (!b)
1092 goto out_undo_partial_alloc;
1093 group_info->blocks[i] = b;
1094 }
1095 }
1096 return group_info;
1097
1098 out_undo_partial_alloc:
1099 while (--i >= 0) {
1100 free_page((unsigned long)group_info->blocks[i]);
1101 }
1102 kfree(group_info);
1103 return NULL;
1104 }
1105
1106 EXPORT_SYMBOL(groups_alloc);
1107
1108 void groups_free(struct group_info *group_info)
1109 {
1110 if (group_info->blocks[0] != group_info->small_block) {
1111 int i;
1112 for (i = 0; i < group_info->nblocks; i++)
1113 free_page((unsigned long)group_info->blocks[i]);
1114 }
1115 kfree(group_info);
1116 }
1117
1118 EXPORT_SYMBOL(groups_free);
1119
1120 /* export the group_info to a user-space array */
1121 static int groups_to_user(gid_t __user *grouplist,
1122 struct group_info *group_info)
1123 {
1124 int i;
1125 unsigned int count = group_info->ngroups;
1126
1127 for (i = 0; i < group_info->nblocks; i++) {
1128 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1129 unsigned int len = cp_count * sizeof(*grouplist);
1130
1131 if (copy_to_user(grouplist, group_info->blocks[i], len))
1132 return -EFAULT;
1133
1134 grouplist += NGROUPS_PER_BLOCK;
1135 count -= cp_count;
1136 }
1137 return 0;
1138 }
1139
1140 /* fill a group_info from a user-space array - it must be allocated already */
1141 static int groups_from_user(struct group_info *group_info,
1142 gid_t __user *grouplist)
1143 {
1144 int i;
1145 unsigned int count = group_info->ngroups;
1146
1147 for (i = 0; i < group_info->nblocks; i++) {
1148 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1149 unsigned int len = cp_count * sizeof(*grouplist);
1150
1151 if (copy_from_user(group_info->blocks[i], grouplist, len))
1152 return -EFAULT;
1153
1154 grouplist += NGROUPS_PER_BLOCK;
1155 count -= cp_count;
1156 }
1157 return 0;
1158 }
1159
1160 /* a simple Shell sort */
1161 static void groups_sort(struct group_info *group_info)
1162 {
1163 int base, max, stride;
1164 int gidsetsize = group_info->ngroups;
1165
1166 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1167 ; /* nothing */
1168 stride /= 3;
1169
1170 while (stride) {
1171 max = gidsetsize - stride;
1172 for (base = 0; base < max; base++) {
1173 int left = base;
1174 int right = left + stride;
1175 gid_t tmp = GROUP_AT(group_info, right);
1176
1177 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1178 GROUP_AT(group_info, right) =
1179 GROUP_AT(group_info, left);
1180 right = left;
1181 left -= stride;
1182 }
1183 GROUP_AT(group_info, right) = tmp;
1184 }
1185 stride /= 3;
1186 }
1187 }
1188
1189 /* a simple bsearch */
1190 int groups_search(struct group_info *group_info, gid_t grp)
1191 {
1192 unsigned int left, right;
1193
1194 if (!group_info)
1195 return 0;
1196
1197 left = 0;
1198 right = group_info->ngroups;
1199 while (left < right) {
1200 unsigned int mid = (left+right)/2;
1201 int cmp = grp - GROUP_AT(group_info, mid);
1202 if (cmp > 0)
1203 left = mid + 1;
1204 else if (cmp < 0)
1205 right = mid;
1206 else
1207 return 1;
1208 }
1209 return 0;
1210 }
1211
1212 /* validate and set current->group_info */
1213 int set_current_groups(struct group_info *group_info)
1214 {
1215 int retval;
1216 struct group_info *old_info;
1217
1218 retval = security_task_setgroups(group_info);
1219 if (retval)
1220 return retval;
1221
1222 groups_sort(group_info);
1223 get_group_info(group_info);
1224
1225 task_lock(current);
1226 old_info = current->group_info;
1227 current->group_info = group_info;
1228 task_unlock(current);
1229
1230 put_group_info(old_info);
1231
1232 return 0;
1233 }
1234
1235 EXPORT_SYMBOL(set_current_groups);
1236
1237 SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
1238 {
1239 int i = 0;
1240
1241 /*
1242 * SMP: Nobody else can change our grouplist. Thus we are
1243 * safe.
1244 */
1245
1246 if (gidsetsize < 0)
1247 return -EINVAL;
1248
1249 /* no need to grab task_lock here; it cannot change */
1250 i = current->group_info->ngroups;
1251 if (gidsetsize) {
1252 if (i > gidsetsize) {
1253 i = -EINVAL;
1254 goto out;
1255 }
1256 if (groups_to_user(grouplist, current->group_info)) {
1257 i = -EFAULT;
1258 goto out;
1259 }
1260 }
1261 out:
1262 return i;
1263 }
1264
1265 /*
1266 * SMP: Our groups are copy-on-write. We can set them safely
1267 * without another task interfering.
1268 */
1269
1270 SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
1271 {
1272 struct group_info *group_info;
1273 int retval;
1274
1275 if (!capable(CAP_SETGID))
1276 return -EPERM;
1277 if ((unsigned)gidsetsize > NGROUPS_MAX)
1278 return -EINVAL;
1279
1280 group_info = groups_alloc(gidsetsize);
1281 if (!group_info)
1282 return -ENOMEM;
1283 retval = groups_from_user(group_info, grouplist);
1284 if (retval) {
1285 put_group_info(group_info);
1286 return retval;
1287 }
1288
1289 retval = set_current_groups(group_info);
1290 put_group_info(group_info);
1291
1292 return retval;
1293 }
1294
1295 /*
1296 * Check whether we're fsgid/egid or in the supplemental group..
1297 */
1298 int in_group_p(gid_t grp)
1299 {
1300 int retval = 1;
1301 if (grp != current->fsgid)
1302 retval = groups_search(current->group_info, grp);
1303 return retval;
1304 }
1305
1306 EXPORT_SYMBOL(in_group_p);
1307
1308 int in_egroup_p(gid_t grp)
1309 {
1310 int retval = 1;
1311 if (grp != current->egid)
1312 retval = groups_search(current->group_info, grp);
1313 return retval;
1314 }
1315
1316 EXPORT_SYMBOL(in_egroup_p);
1317
1318 DECLARE_RWSEM(uts_sem);
1319
1320 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1321 {
1322 int errno = 0;
1323
1324 down_read(&uts_sem);
1325 if (copy_to_user(name, utsname(), sizeof *name))
1326 errno = -EFAULT;
1327 up_read(&uts_sem);
1328 return errno;
1329 }
1330
1331 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1332 {
1333 int errno;
1334 char tmp[__NEW_UTS_LEN];
1335
1336 if (!capable(CAP_SYS_ADMIN))
1337 return -EPERM;
1338 if (len < 0 || len > __NEW_UTS_LEN)
1339 return -EINVAL;
1340 down_write(&uts_sem);
1341 errno = -EFAULT;
1342 if (!copy_from_user(tmp, name, len)) {
1343 struct new_utsname *u = utsname();
1344
1345 memcpy(u->nodename, tmp, len);
1346 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1347 errno = 0;
1348 }
1349 up_write(&uts_sem);
1350 return errno;
1351 }
1352
1353 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1354
1355 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1356 {
1357 int i, errno;
1358 struct new_utsname *u;
1359
1360 if (len < 0)
1361 return -EINVAL;
1362 down_read(&uts_sem);
1363 u = utsname();
1364 i = 1 + strlen(u->nodename);
1365 if (i > len)
1366 i = len;
1367 errno = 0;
1368 if (copy_to_user(name, u->nodename, i))
1369 errno = -EFAULT;
1370 up_read(&uts_sem);
1371 return errno;
1372 }
1373
1374 #endif
1375
1376 /*
1377 * Only setdomainname; getdomainname can be implemented by calling
1378 * uname()
1379 */
1380 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1381 {
1382 int errno;
1383 char tmp[__NEW_UTS_LEN];
1384
1385 if (!capable(CAP_SYS_ADMIN))
1386 return -EPERM;
1387 if (len < 0 || len > __NEW_UTS_LEN)
1388 return -EINVAL;
1389
1390 down_write(&uts_sem);
1391 errno = -EFAULT;
1392 if (!copy_from_user(tmp, name, len)) {
1393 struct new_utsname *u = utsname();
1394
1395 memcpy(u->domainname, tmp, len);
1396 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1397 errno = 0;
1398 }
1399 up_write(&uts_sem);
1400 return errno;
1401 }
1402
1403 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1404 {
1405 if (resource >= RLIM_NLIMITS)
1406 return -EINVAL;
1407 else {
1408 struct rlimit value;
1409 task_lock(current->group_leader);
1410 value = current->signal->rlim[resource];
1411 task_unlock(current->group_leader);
1412 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1413 }
1414 }
1415
1416 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1417
1418 /*
1419 * Back compatibility for getrlimit. Needed for some apps.
1420 */
1421
1422 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1423 struct rlimit __user *, rlim)
1424 {
1425 struct rlimit x;
1426 if (resource >= RLIM_NLIMITS)
1427 return -EINVAL;
1428
1429 task_lock(current->group_leader);
1430 x = current->signal->rlim[resource];
1431 task_unlock(current->group_leader);
1432 if (x.rlim_cur > 0x7FFFFFFF)
1433 x.rlim_cur = 0x7FFFFFFF;
1434 if (x.rlim_max > 0x7FFFFFFF)
1435 x.rlim_max = 0x7FFFFFFF;
1436 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1437 }
1438
1439 #endif
1440
1441 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1442 {
1443 struct rlimit new_rlim, *old_rlim;
1444 int retval;
1445
1446 if (resource >= RLIM_NLIMITS)
1447 return -EINVAL;
1448 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1449 return -EFAULT;
1450 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1451 return -EINVAL;
1452 old_rlim = current->signal->rlim + resource;
1453 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1454 !capable(CAP_SYS_RESOURCE))
1455 return -EPERM;
1456 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1457 return -EPERM;
1458
1459 retval = security_task_setrlimit(resource, &new_rlim);
1460 if (retval)
1461 return retval;
1462
1463 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1464 /*
1465 * The caller is asking for an immediate RLIMIT_CPU
1466 * expiry. But we use the zero value to mean "it was
1467 * never set". So let's cheat and make it one second
1468 * instead
1469 */
1470 new_rlim.rlim_cur = 1;
1471 }
1472
1473 task_lock(current->group_leader);
1474 *old_rlim = new_rlim;
1475 task_unlock(current->group_leader);
1476
1477 if (resource != RLIMIT_CPU)
1478 goto out;
1479
1480 /*
1481 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1482 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1483 * very long-standing error, and fixing it now risks breakage of
1484 * applications, so we live with it
1485 */
1486 if (new_rlim.rlim_cur == RLIM_INFINITY)
1487 goto out;
1488
1489 update_rlimit_cpu(new_rlim.rlim_cur);
1490 out:
1491 return 0;
1492 }
1493
1494 /*
1495 * It would make sense to put struct rusage in the task_struct,
1496 * except that would make the task_struct be *really big*. After
1497 * task_struct gets moved into malloc'ed memory, it would
1498 * make sense to do this. It will make moving the rest of the information
1499 * a lot simpler! (Which we're not doing right now because we're not
1500 * measuring them yet).
1501 *
1502 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1503 * races with threads incrementing their own counters. But since word
1504 * reads are atomic, we either get new values or old values and we don't
1505 * care which for the sums. We always take the siglock to protect reading
1506 * the c* fields from p->signal from races with exit.c updating those
1507 * fields when reaping, so a sample either gets all the additions of a
1508 * given child after it's reaped, or none so this sample is before reaping.
1509 *
1510 * Locking:
1511 * We need to take the siglock for CHILDEREN, SELF and BOTH
1512 * for the cases current multithreaded, non-current single threaded
1513 * non-current multithreaded. Thread traversal is now safe with
1514 * the siglock held.
1515 * Strictly speaking, we donot need to take the siglock if we are current and
1516 * single threaded, as no one else can take our signal_struct away, no one
1517 * else can reap the children to update signal->c* counters, and no one else
1518 * can race with the signal-> fields. If we do not take any lock, the
1519 * signal-> fields could be read out of order while another thread was just
1520 * exiting. So we should place a read memory barrier when we avoid the lock.
1521 * On the writer side, write memory barrier is implied in __exit_signal
1522 * as __exit_signal releases the siglock spinlock after updating the signal->
1523 * fields. But we don't do this yet to keep things simple.
1524 *
1525 */
1526
1527 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1528 {
1529 r->ru_nvcsw += t->nvcsw;
1530 r->ru_nivcsw += t->nivcsw;
1531 r->ru_minflt += t->min_flt;
1532 r->ru_majflt += t->maj_flt;
1533 r->ru_inblock += task_io_get_inblock(t);
1534 r->ru_oublock += task_io_get_oublock(t);
1535 }
1536
1537 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1538 {
1539 struct task_struct *t;
1540 unsigned long flags;
1541 cputime_t utime, stime;
1542 struct task_cputime cputime;
1543
1544 memset((char *) r, 0, sizeof *r);
1545 utime = stime = cputime_zero;
1546
1547 if (who == RUSAGE_THREAD) {
1548 utime = task_utime(current);
1549 stime = task_stime(current);
1550 accumulate_thread_rusage(p, r);
1551 goto out;
1552 }
1553
1554 if (!lock_task_sighand(p, &flags))
1555 return;
1556
1557 switch (who) {
1558 case RUSAGE_BOTH:
1559 case RUSAGE_CHILDREN:
1560 utime = p->signal->cutime;
1561 stime = p->signal->cstime;
1562 r->ru_nvcsw = p->signal->cnvcsw;
1563 r->ru_nivcsw = p->signal->cnivcsw;
1564 r->ru_minflt = p->signal->cmin_flt;
1565 r->ru_majflt = p->signal->cmaj_flt;
1566 r->ru_inblock = p->signal->cinblock;
1567 r->ru_oublock = p->signal->coublock;
1568
1569 if (who == RUSAGE_CHILDREN)
1570 break;
1571
1572 case RUSAGE_SELF:
1573 thread_group_cputime(p, &cputime);
1574 utime = cputime_add(utime, cputime.utime);
1575 stime = cputime_add(stime, cputime.stime);
1576 r->ru_nvcsw += p->signal->nvcsw;
1577 r->ru_nivcsw += p->signal->nivcsw;
1578 r->ru_minflt += p->signal->min_flt;
1579 r->ru_majflt += p->signal->maj_flt;
1580 r->ru_inblock += p->signal->inblock;
1581 r->ru_oublock += p->signal->oublock;
1582 t = p;
1583 do {
1584 accumulate_thread_rusage(t, r);
1585 t = next_thread(t);
1586 } while (t != p);
1587 break;
1588
1589 default:
1590 BUG();
1591 }
1592 unlock_task_sighand(p, &flags);
1593
1594 out:
1595 cputime_to_timeval(utime, &r->ru_utime);
1596 cputime_to_timeval(stime, &r->ru_stime);
1597 }
1598
1599 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1600 {
1601 struct rusage r;
1602 k_getrusage(p, who, &r);
1603 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1604 }
1605
1606 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1607 {
1608 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1609 who != RUSAGE_THREAD)
1610 return -EINVAL;
1611 return getrusage(current, who, ru);
1612 }
1613
1614 SYSCALL_DEFINE1(umask, int, mask)
1615 {
1616 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1617 return mask;
1618 }
1619
1620 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1621 unsigned long, arg4, unsigned long, arg5)
1622 {
1623 long error = 0;
1624
1625 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1626 return error;
1627
1628 switch (option) {
1629 case PR_SET_PDEATHSIG:
1630 if (!valid_signal(arg2)) {
1631 error = -EINVAL;
1632 break;
1633 }
1634 current->pdeath_signal = arg2;
1635 break;
1636 case PR_GET_PDEATHSIG:
1637 error = put_user(current->pdeath_signal, (int __user *)arg2);
1638 break;
1639 case PR_GET_DUMPABLE:
1640 error = get_dumpable(current->mm);
1641 break;
1642 case PR_SET_DUMPABLE:
1643 if (arg2 < 0 || arg2 > 1) {
1644 error = -EINVAL;
1645 break;
1646 }
1647 set_dumpable(current->mm, arg2);
1648 break;
1649
1650 case PR_SET_UNALIGN:
1651 error = SET_UNALIGN_CTL(current, arg2);
1652 break;
1653 case PR_GET_UNALIGN:
1654 error = GET_UNALIGN_CTL(current, arg2);
1655 break;
1656 case PR_SET_FPEMU:
1657 error = SET_FPEMU_CTL(current, arg2);
1658 break;
1659 case PR_GET_FPEMU:
1660 error = GET_FPEMU_CTL(current, arg2);
1661 break;
1662 case PR_SET_FPEXC:
1663 error = SET_FPEXC_CTL(current, arg2);
1664 break;
1665 case PR_GET_FPEXC:
1666 error = GET_FPEXC_CTL(current, arg2);
1667 break;
1668 case PR_GET_TIMING:
1669 error = PR_TIMING_STATISTICAL;
1670 break;
1671 case PR_SET_TIMING:
1672 if (arg2 != PR_TIMING_STATISTICAL)
1673 error = -EINVAL;
1674 break;
1675
1676 case PR_SET_NAME: {
1677 struct task_struct *me = current;
1678 unsigned char ncomm[sizeof(me->comm)];
1679
1680 ncomm[sizeof(me->comm)-1] = 0;
1681 if (strncpy_from_user(ncomm, (char __user *)arg2,
1682 sizeof(me->comm)-1) < 0)
1683 return -EFAULT;
1684 set_task_comm(me, ncomm);
1685 return 0;
1686 }
1687 case PR_GET_NAME: {
1688 struct task_struct *me = current;
1689 unsigned char tcomm[sizeof(me->comm)];
1690
1691 get_task_comm(tcomm, me);
1692 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1693 return -EFAULT;
1694 return 0;
1695 }
1696 case PR_GET_ENDIAN:
1697 error = GET_ENDIAN(current, arg2);
1698 break;
1699 case PR_SET_ENDIAN:
1700 error = SET_ENDIAN(current, arg2);
1701 break;
1702
1703 case PR_GET_SECCOMP:
1704 error = prctl_get_seccomp();
1705 break;
1706 case PR_SET_SECCOMP:
1707 error = prctl_set_seccomp(arg2);
1708 break;
1709 case PR_GET_TSC:
1710 error = GET_TSC_CTL(arg2);
1711 break;
1712 case PR_SET_TSC:
1713 error = SET_TSC_CTL(arg2);
1714 break;
1715 case PR_GET_TIMERSLACK:
1716 error = current->timer_slack_ns;
1717 break;
1718 case PR_SET_TIMERSLACK:
1719 if (arg2 <= 0)
1720 current->timer_slack_ns =
1721 current->default_timer_slack_ns;
1722 else
1723 current->timer_slack_ns = arg2;
1724 break;
1725 default:
1726 error = -EINVAL;
1727 break;
1728 }
1729 return error;
1730 }
1731
1732 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1733 struct getcpu_cache __user *, unused)
1734 {
1735 int err = 0;
1736 int cpu = raw_smp_processor_id();
1737 if (cpup)
1738 err |= put_user(cpu, cpup);
1739 if (nodep)
1740 err |= put_user(cpu_to_node(cpu), nodep);
1741 return err ? -EFAULT : 0;
1742 }
1743
1744 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1745
1746 static void argv_cleanup(char **argv, char **envp)
1747 {
1748 argv_free(argv);
1749 }
1750
1751 /**
1752 * orderly_poweroff - Trigger an orderly system poweroff
1753 * @force: force poweroff if command execution fails
1754 *
1755 * This may be called from any context to trigger a system shutdown.
1756 * If the orderly shutdown fails, it will force an immediate shutdown.
1757 */
1758 int orderly_poweroff(bool force)
1759 {
1760 int argc;
1761 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1762 static char *envp[] = {
1763 "HOME=/",
1764 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1765 NULL
1766 };
1767 int ret = -ENOMEM;
1768 struct subprocess_info *info;
1769
1770 if (argv == NULL) {
1771 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1772 __func__, poweroff_cmd);
1773 goto out;
1774 }
1775
1776 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1777 if (info == NULL) {
1778 argv_free(argv);
1779 goto out;
1780 }
1781
1782 call_usermodehelper_setcleanup(info, argv_cleanup);
1783
1784 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1785
1786 out:
1787 if (ret && force) {
1788 printk(KERN_WARNING "Failed to start orderly shutdown: "
1789 "forcing the issue\n");
1790
1791 /* I guess this should try to kick off some daemon to
1792 sync and poweroff asap. Or not even bother syncing
1793 if we're doing an emergency shutdown? */
1794 emergency_sync();
1795 kernel_power_off();
1796 }
1797
1798 return ret;
1799 }
1800 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree