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Linux 2.6.28-rc5
[cris-mirror.git] / kernel / sys.c
blob31deba8f7d160c19bf262b1be13272e2ede1050d
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_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 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_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 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 void do_sys_times(struct tms *tms)
857 {
858 struct task_cputime cputime;
859 cputime_t cutime, cstime;
860
861 spin_lock_irq(&current->sighand->siglock);
862 thread_group_cputime(current, &cputime);
863 cutime = current->signal->cutime;
864 cstime = current->signal->cstime;
865 spin_unlock_irq(&current->sighand->siglock);
866 tms->tms_utime = cputime_to_clock_t(cputime.utime);
867 tms->tms_stime = cputime_to_clock_t(cputime.stime);
868 tms->tms_cutime = cputime_to_clock_t(cutime);
869 tms->tms_cstime = cputime_to_clock_t(cstime);
870 }
871
872 asmlinkage long sys_times(struct tms __user * tbuf)
873 {
874 if (tbuf) {
875 struct tms tmp;
876
877 do_sys_times(&tmp);
878 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
879 return -EFAULT;
880 }
881 return (long) jiffies_64_to_clock_t(get_jiffies_64());
882 }
883
884 /*
885 * This needs some heavy checking ...
886 * I just haven't the stomach for it. I also don't fully
887 * understand sessions/pgrp etc. Let somebody who does explain it.
888 *
889 * OK, I think I have the protection semantics right.... this is really
890 * only important on a multi-user system anyway, to make sure one user
891 * can't send a signal to a process owned by another. -TYT, 12/12/91
892 *
893 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
894 * LBT 04.03.94
895 */
896 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
897 {
898 struct task_struct *p;
899 struct task_struct *group_leader = current->group_leader;
900 struct pid *pgrp;
901 int err;
902
903 if (!pid)
904 pid = task_pid_vnr(group_leader);
905 if (!pgid)
906 pgid = pid;
907 if (pgid < 0)
908 return -EINVAL;
909
910 /* From this point forward we keep holding onto the tasklist lock
911 * so that our parent does not change from under us. -DaveM
912 */
913 write_lock_irq(&tasklist_lock);
914
915 err = -ESRCH;
916 p = find_task_by_vpid(pid);
917 if (!p)
918 goto out;
919
920 err = -EINVAL;
921 if (!thread_group_leader(p))
922 goto out;
923
924 if (same_thread_group(p->real_parent, group_leader)) {
925 err = -EPERM;
926 if (task_session(p) != task_session(group_leader))
927 goto out;
928 err = -EACCES;
929 if (p->did_exec)
930 goto out;
931 } else {
932 err = -ESRCH;
933 if (p != group_leader)
934 goto out;
935 }
936
937 err = -EPERM;
938 if (p->signal->leader)
939 goto out;
940
941 pgrp = task_pid(p);
942 if (pgid != pid) {
943 struct task_struct *g;
944
945 pgrp = find_vpid(pgid);
946 g = pid_task(pgrp, PIDTYPE_PGID);
947 if (!g || task_session(g) != task_session(group_leader))
948 goto out;
949 }
950
951 err = security_task_setpgid(p, pgid);
952 if (err)
953 goto out;
954
955 if (task_pgrp(p) != pgrp) {
956 change_pid(p, PIDTYPE_PGID, pgrp);
957 set_task_pgrp(p, pid_nr(pgrp));
958 }
959
960 err = 0;
961 out:
962 /* All paths lead to here, thus we are safe. -DaveM */
963 write_unlock_irq(&tasklist_lock);
964 return err;
965 }
966
967 asmlinkage long sys_getpgid(pid_t pid)
968 {
969 struct task_struct *p;
970 struct pid *grp;
971 int retval;
972
973 rcu_read_lock();
974 if (!pid)
975 grp = task_pgrp(current);
976 else {
977 retval = -ESRCH;
978 p = find_task_by_vpid(pid);
979 if (!p)
980 goto out;
981 grp = task_pgrp(p);
982 if (!grp)
983 goto out;
984
985 retval = security_task_getpgid(p);
986 if (retval)
987 goto out;
988 }
989 retval = pid_vnr(grp);
990 out:
991 rcu_read_unlock();
992 return retval;
993 }
994
995 #ifdef __ARCH_WANT_SYS_GETPGRP
996
997 asmlinkage long sys_getpgrp(void)
998 {
999 return sys_getpgid(0);
1000 }
1001
1002 #endif
1003
1004 asmlinkage long sys_getsid(pid_t pid)
1005 {
1006 struct task_struct *p;
1007 struct pid *sid;
1008 int retval;
1009
1010 rcu_read_lock();
1011 if (!pid)
1012 sid = task_session(current);
1013 else {
1014 retval = -ESRCH;
1015 p = find_task_by_vpid(pid);
1016 if (!p)
1017 goto out;
1018 sid = task_session(p);
1019 if (!sid)
1020 goto out;
1021
1022 retval = security_task_getsid(p);
1023 if (retval)
1024 goto out;
1025 }
1026 retval = pid_vnr(sid);
1027 out:
1028 rcu_read_unlock();
1029 return retval;
1030 }
1031
1032 asmlinkage long sys_setsid(void)
1033 {
1034 struct task_struct *group_leader = current->group_leader;
1035 struct pid *sid = task_pid(group_leader);
1036 pid_t session = pid_vnr(sid);
1037 int err = -EPERM;
1038
1039 write_lock_irq(&tasklist_lock);
1040 /* Fail if I am already a session leader */
1041 if (group_leader->signal->leader)
1042 goto out;
1043
1044 /* Fail if a process group id already exists that equals the
1045 * proposed session id.
1046 */
1047 if (pid_task(sid, PIDTYPE_PGID))
1048 goto out;
1049
1050 group_leader->signal->leader = 1;
1051 __set_special_pids(sid);
1052
1053 proc_clear_tty(group_leader);
1054
1055 err = session;
1056 out:
1057 write_unlock_irq(&tasklist_lock);
1058 return err;
1059 }
1060
1061 /*
1062 * Supplementary group IDs
1063 */
1064
1065 /* init to 2 - one for init_task, one to ensure it is never freed */
1066 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1067
1068 struct group_info *groups_alloc(int gidsetsize)
1069 {
1070 struct group_info *group_info;
1071 int nblocks;
1072 int i;
1073
1074 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1075 /* Make sure we always allocate at least one indirect block pointer */
1076 nblocks = nblocks ? : 1;
1077 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1078 if (!group_info)
1079 return NULL;
1080 group_info->ngroups = gidsetsize;
1081 group_info->nblocks = nblocks;
1082 atomic_set(&group_info->usage, 1);
1083
1084 if (gidsetsize <= NGROUPS_SMALL)
1085 group_info->blocks[0] = group_info->small_block;
1086 else {
1087 for (i = 0; i < nblocks; i++) {
1088 gid_t *b;
1089 b = (void *)__get_free_page(GFP_USER);
1090 if (!b)
1091 goto out_undo_partial_alloc;
1092 group_info->blocks[i] = b;
1093 }
1094 }
1095 return group_info;
1096
1097 out_undo_partial_alloc:
1098 while (--i >= 0) {
1099 free_page((unsigned long)group_info->blocks[i]);
1100 }
1101 kfree(group_info);
1102 return NULL;
1103 }
1104
1105 EXPORT_SYMBOL(groups_alloc);
1106
1107 void groups_free(struct group_info *group_info)
1108 {
1109 if (group_info->blocks[0] != group_info->small_block) {
1110 int i;
1111 for (i = 0; i < group_info->nblocks; i++)
1112 free_page((unsigned long)group_info->blocks[i]);
1113 }
1114 kfree(group_info);
1115 }
1116
1117 EXPORT_SYMBOL(groups_free);
1118
1119 /* export the group_info to a user-space array */
1120 static int groups_to_user(gid_t __user *grouplist,
1121 struct group_info *group_info)
1122 {
1123 int i;
1124 unsigned int count = group_info->ngroups;
1125
1126 for (i = 0; i < group_info->nblocks; i++) {
1127 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1128 unsigned int len = cp_count * sizeof(*grouplist);
1129
1130 if (copy_to_user(grouplist, group_info->blocks[i], len))
1131 return -EFAULT;
1132
1133 grouplist += NGROUPS_PER_BLOCK;
1134 count -= cp_count;
1135 }
1136 return 0;
1137 }
1138
1139 /* fill a group_info from a user-space array - it must be allocated already */
1140 static int groups_from_user(struct group_info *group_info,
1141 gid_t __user *grouplist)
1142 {
1143 int i;
1144 unsigned int count = group_info->ngroups;
1145
1146 for (i = 0; i < group_info->nblocks; i++) {
1147 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1148 unsigned int len = cp_count * sizeof(*grouplist);
1149
1150 if (copy_from_user(group_info->blocks[i], grouplist, len))
1151 return -EFAULT;
1152
1153 grouplist += NGROUPS_PER_BLOCK;
1154 count -= cp_count;
1155 }
1156 return 0;
1157 }
1158
1159 /* a simple Shell sort */
1160 static void groups_sort(struct group_info *group_info)
1161 {
1162 int base, max, stride;
1163 int gidsetsize = group_info->ngroups;
1164
1165 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1166 ; /* nothing */
1167 stride /= 3;
1168
1169 while (stride) {
1170 max = gidsetsize - stride;
1171 for (base = 0; base < max; base++) {
1172 int left = base;
1173 int right = left + stride;
1174 gid_t tmp = GROUP_AT(group_info, right);
1175
1176 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1177 GROUP_AT(group_info, right) =
1178 GROUP_AT(group_info, left);
1179 right = left;
1180 left -= stride;
1181 }
1182 GROUP_AT(group_info, right) = tmp;
1183 }
1184 stride /= 3;
1185 }
1186 }
1187
1188 /* a simple bsearch */
1189 int groups_search(struct group_info *group_info, gid_t grp)
1190 {
1191 unsigned int left, right;
1192
1193 if (!group_info)
1194 return 0;
1195
1196 left = 0;
1197 right = group_info->ngroups;
1198 while (left < right) {
1199 unsigned int mid = (left+right)/2;
1200 int cmp = grp - GROUP_AT(group_info, mid);
1201 if (cmp > 0)
1202 left = mid + 1;
1203 else if (cmp < 0)
1204 right = mid;
1205 else
1206 return 1;
1207 }
1208 return 0;
1209 }
1210
1211 /* validate and set current->group_info */
1212 int set_current_groups(struct group_info *group_info)
1213 {
1214 int retval;
1215 struct group_info *old_info;
1216
1217 retval = security_task_setgroups(group_info);
1218 if (retval)
1219 return retval;
1220
1221 groups_sort(group_info);
1222 get_group_info(group_info);
1223
1224 task_lock(current);
1225 old_info = current->group_info;
1226 current->group_info = group_info;
1227 task_unlock(current);
1228
1229 put_group_info(old_info);
1230
1231 return 0;
1232 }
1233
1234 EXPORT_SYMBOL(set_current_groups);
1235
1236 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1237 {
1238 int i = 0;
1239
1240 /*
1241 * SMP: Nobody else can change our grouplist. Thus we are
1242 * safe.
1243 */
1244
1245 if (gidsetsize < 0)
1246 return -EINVAL;
1247
1248 /* no need to grab task_lock here; it cannot change */
1249 i = current->group_info->ngroups;
1250 if (gidsetsize) {
1251 if (i > gidsetsize) {
1252 i = -EINVAL;
1253 goto out;
1254 }
1255 if (groups_to_user(grouplist, current->group_info)) {
1256 i = -EFAULT;
1257 goto out;
1258 }
1259 }
1260 out:
1261 return i;
1262 }
1263
1264 /*
1265 * SMP: Our groups are copy-on-write. We can set them safely
1266 * without another task interfering.
1267 */
1268
1269 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1270 {
1271 struct group_info *group_info;
1272 int retval;
1273
1274 if (!capable(CAP_SETGID))
1275 return -EPERM;
1276 if ((unsigned)gidsetsize > NGROUPS_MAX)
1277 return -EINVAL;
1278
1279 group_info = groups_alloc(gidsetsize);
1280 if (!group_info)
1281 return -ENOMEM;
1282 retval = groups_from_user(group_info, grouplist);
1283 if (retval) {
1284 put_group_info(group_info);
1285 return retval;
1286 }
1287
1288 retval = set_current_groups(group_info);
1289 put_group_info(group_info);
1290
1291 return retval;
1292 }
1293
1294 /*
1295 * Check whether we're fsgid/egid or in the supplemental group..
1296 */
1297 int in_group_p(gid_t grp)
1298 {
1299 int retval = 1;
1300 if (grp != current->fsgid)
1301 retval = groups_search(current->group_info, grp);
1302 return retval;
1303 }
1304
1305 EXPORT_SYMBOL(in_group_p);
1306
1307 int in_egroup_p(gid_t grp)
1308 {
1309 int retval = 1;
1310 if (grp != current->egid)
1311 retval = groups_search(current->group_info, grp);
1312 return retval;
1313 }
1314
1315 EXPORT_SYMBOL(in_egroup_p);
1316
1317 DECLARE_RWSEM(uts_sem);
1318
1319 asmlinkage long sys_newuname(struct new_utsname __user * name)
1320 {
1321 int errno = 0;
1322
1323 down_read(&uts_sem);
1324 if (copy_to_user(name, utsname(), sizeof *name))
1325 errno = -EFAULT;
1326 up_read(&uts_sem);
1327 return errno;
1328 }
1329
1330 asmlinkage long sys_sethostname(char __user *name, int len)
1331 {
1332 int errno;
1333 char tmp[__NEW_UTS_LEN];
1334
1335 if (!capable(CAP_SYS_ADMIN))
1336 return -EPERM;
1337 if (len < 0 || len > __NEW_UTS_LEN)
1338 return -EINVAL;
1339 down_write(&uts_sem);
1340 errno = -EFAULT;
1341 if (!copy_from_user(tmp, name, len)) {
1342 struct new_utsname *u = utsname();
1343
1344 memcpy(u->nodename, tmp, len);
1345 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1346 errno = 0;
1347 }
1348 up_write(&uts_sem);
1349 return errno;
1350 }
1351
1352 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1353
1354 asmlinkage long sys_gethostname(char __user *name, int len)
1355 {
1356 int i, errno;
1357 struct new_utsname *u;
1358
1359 if (len < 0)
1360 return -EINVAL;
1361 down_read(&uts_sem);
1362 u = utsname();
1363 i = 1 + strlen(u->nodename);
1364 if (i > len)
1365 i = len;
1366 errno = 0;
1367 if (copy_to_user(name, u->nodename, i))
1368 errno = -EFAULT;
1369 up_read(&uts_sem);
1370 return errno;
1371 }
1372
1373 #endif
1374
1375 /*
1376 * Only setdomainname; getdomainname can be implemented by calling
1377 * uname()
1378 */
1379 asmlinkage long sys_setdomainname(char __user *name, int len)
1380 {
1381 int errno;
1382 char tmp[__NEW_UTS_LEN];
1383
1384 if (!capable(CAP_SYS_ADMIN))
1385 return -EPERM;
1386 if (len < 0 || len > __NEW_UTS_LEN)
1387 return -EINVAL;
1388
1389 down_write(&uts_sem);
1390 errno = -EFAULT;
1391 if (!copy_from_user(tmp, name, len)) {
1392 struct new_utsname *u = utsname();
1393
1394 memcpy(u->domainname, tmp, len);
1395 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1396 errno = 0;
1397 }
1398 up_write(&uts_sem);
1399 return errno;
1400 }
1401
1402 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1403 {
1404 if (resource >= RLIM_NLIMITS)
1405 return -EINVAL;
1406 else {
1407 struct rlimit value;
1408 task_lock(current->group_leader);
1409 value = current->signal->rlim[resource];
1410 task_unlock(current->group_leader);
1411 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1412 }
1413 }
1414
1415 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1416
1417 /*
1418 * Back compatibility for getrlimit. Needed for some apps.
1419 */
1420
1421 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1422 {
1423 struct rlimit x;
1424 if (resource >= RLIM_NLIMITS)
1425 return -EINVAL;
1426
1427 task_lock(current->group_leader);
1428 x = current->signal->rlim[resource];
1429 task_unlock(current->group_leader);
1430 if (x.rlim_cur > 0x7FFFFFFF)
1431 x.rlim_cur = 0x7FFFFFFF;
1432 if (x.rlim_max > 0x7FFFFFFF)
1433 x.rlim_max = 0x7FFFFFFF;
1434 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1435 }
1436
1437 #endif
1438
1439 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1440 {
1441 struct rlimit new_rlim, *old_rlim;
1442 int retval;
1443
1444 if (resource >= RLIM_NLIMITS)
1445 return -EINVAL;
1446 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1447 return -EFAULT;
1448 old_rlim = current->signal->rlim + resource;
1449 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1450 !capable(CAP_SYS_RESOURCE))
1451 return -EPERM;
1452
1453 if (resource == RLIMIT_NOFILE) {
1454 if (new_rlim.rlim_max == RLIM_INFINITY)
1455 new_rlim.rlim_max = sysctl_nr_open;
1456 if (new_rlim.rlim_cur == RLIM_INFINITY)
1457 new_rlim.rlim_cur = sysctl_nr_open;
1458 if (new_rlim.rlim_max > sysctl_nr_open)
1459 return -EPERM;
1460 }
1461
1462 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1463 return -EINVAL;
1464
1465 retval = security_task_setrlimit(resource, &new_rlim);
1466 if (retval)
1467 return retval;
1468
1469 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1470 /*
1471 * The caller is asking for an immediate RLIMIT_CPU
1472 * expiry. But we use the zero value to mean "it was
1473 * never set". So let's cheat and make it one second
1474 * instead
1475 */
1476 new_rlim.rlim_cur = 1;
1477 }
1478
1479 task_lock(current->group_leader);
1480 *old_rlim = new_rlim;
1481 task_unlock(current->group_leader);
1482
1483 if (resource != RLIMIT_CPU)
1484 goto out;
1485
1486 /*
1487 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1488 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1489 * very long-standing error, and fixing it now risks breakage of
1490 * applications, so we live with it
1491 */
1492 if (new_rlim.rlim_cur == RLIM_INFINITY)
1493 goto out;
1494
1495 update_rlimit_cpu(new_rlim.rlim_cur);
1496 out:
1497 return 0;
1498 }
1499
1500 /*
1501 * It would make sense to put struct rusage in the task_struct,
1502 * except that would make the task_struct be *really big*. After
1503 * task_struct gets moved into malloc'ed memory, it would
1504 * make sense to do this. It will make moving the rest of the information
1505 * a lot simpler! (Which we're not doing right now because we're not
1506 * measuring them yet).
1507 *
1508 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1509 * races with threads incrementing their own counters. But since word
1510 * reads are atomic, we either get new values or old values and we don't
1511 * care which for the sums. We always take the siglock to protect reading
1512 * the c* fields from p->signal from races with exit.c updating those
1513 * fields when reaping, so a sample either gets all the additions of a
1514 * given child after it's reaped, or none so this sample is before reaping.
1515 *
1516 * Locking:
1517 * We need to take the siglock for CHILDEREN, SELF and BOTH
1518 * for the cases current multithreaded, non-current single threaded
1519 * non-current multithreaded. Thread traversal is now safe with
1520 * the siglock held.
1521 * Strictly speaking, we donot need to take the siglock if we are current and
1522 * single threaded, as no one else can take our signal_struct away, no one
1523 * else can reap the children to update signal->c* counters, and no one else
1524 * can race with the signal-> fields. If we do not take any lock, the
1525 * signal-> fields could be read out of order while another thread was just
1526 * exiting. So we should place a read memory barrier when we avoid the lock.
1527 * On the writer side, write memory barrier is implied in __exit_signal
1528 * as __exit_signal releases the siglock spinlock after updating the signal->
1529 * fields. But we don't do this yet to keep things simple.
1530 *
1531 */
1532
1533 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1534 {
1535 r->ru_nvcsw += t->nvcsw;
1536 r->ru_nivcsw += t->nivcsw;
1537 r->ru_minflt += t->min_flt;
1538 r->ru_majflt += t->maj_flt;
1539 r->ru_inblock += task_io_get_inblock(t);
1540 r->ru_oublock += task_io_get_oublock(t);
1541 }
1542
1543 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1544 {
1545 struct task_struct *t;
1546 unsigned long flags;
1547 cputime_t utime, stime;
1548 struct task_cputime cputime;
1549
1550 memset((char *) r, 0, sizeof *r);
1551 utime = stime = cputime_zero;
1552
1553 if (who == RUSAGE_THREAD) {
1554 accumulate_thread_rusage(p, r);
1555 goto out;
1556 }
1557
1558 if (!lock_task_sighand(p, &flags))
1559 return;
1560
1561 switch (who) {
1562 case RUSAGE_BOTH:
1563 case RUSAGE_CHILDREN:
1564 utime = p->signal->cutime;
1565 stime = p->signal->cstime;
1566 r->ru_nvcsw = p->signal->cnvcsw;
1567 r->ru_nivcsw = p->signal->cnivcsw;
1568 r->ru_minflt = p->signal->cmin_flt;
1569 r->ru_majflt = p->signal->cmaj_flt;
1570 r->ru_inblock = p->signal->cinblock;
1571 r->ru_oublock = p->signal->coublock;
1572
1573 if (who == RUSAGE_CHILDREN)
1574 break;
1575
1576 case RUSAGE_SELF:
1577 thread_group_cputime(p, &cputime);
1578 utime = cputime_add(utime, cputime.utime);
1579 stime = cputime_add(stime, cputime.stime);
1580 r->ru_nvcsw += p->signal->nvcsw;
1581 r->ru_nivcsw += p->signal->nivcsw;
1582 r->ru_minflt += p->signal->min_flt;
1583 r->ru_majflt += p->signal->maj_flt;
1584 r->ru_inblock += p->signal->inblock;
1585 r->ru_oublock += p->signal->oublock;
1586 t = p;
1587 do {
1588 accumulate_thread_rusage(t, r);
1589 t = next_thread(t);
1590 } while (t != p);
1591 break;
1592
1593 default:
1594 BUG();
1595 }
1596 unlock_task_sighand(p, &flags);
1597
1598 out:
1599 cputime_to_timeval(utime, &r->ru_utime);
1600 cputime_to_timeval(stime, &r->ru_stime);
1601 }
1602
1603 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1604 {
1605 struct rusage r;
1606 k_getrusage(p, who, &r);
1607 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1608 }
1609
1610 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1611 {
1612 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1613 who != RUSAGE_THREAD)
1614 return -EINVAL;
1615 return getrusage(current, who, ru);
1616 }
1617
1618 asmlinkage long sys_umask(int mask)
1619 {
1620 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1621 return mask;
1622 }
1623
1624 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1625 unsigned long arg4, unsigned long arg5)
1626 {
1627 long error = 0;
1628
1629 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1630 return error;
1631
1632 switch (option) {
1633 case PR_SET_PDEATHSIG:
1634 if (!valid_signal(arg2)) {
1635 error = -EINVAL;
1636 break;
1637 }
1638 current->pdeath_signal = arg2;
1639 break;
1640 case PR_GET_PDEATHSIG:
1641 error = put_user(current->pdeath_signal, (int __user *)arg2);
1642 break;
1643 case PR_GET_DUMPABLE:
1644 error = get_dumpable(current->mm);
1645 break;
1646 case PR_SET_DUMPABLE:
1647 if (arg2 < 0 || arg2 > 1) {
1648 error = -EINVAL;
1649 break;
1650 }
1651 set_dumpable(current->mm, arg2);
1652 break;
1653
1654 case PR_SET_UNALIGN:
1655 error = SET_UNALIGN_CTL(current, arg2);
1656 break;
1657 case PR_GET_UNALIGN:
1658 error = GET_UNALIGN_CTL(current, arg2);
1659 break;
1660 case PR_SET_FPEMU:
1661 error = SET_FPEMU_CTL(current, arg2);
1662 break;
1663 case PR_GET_FPEMU:
1664 error = GET_FPEMU_CTL(current, arg2);
1665 break;
1666 case PR_SET_FPEXC:
1667 error = SET_FPEXC_CTL(current, arg2);
1668 break;
1669 case PR_GET_FPEXC:
1670 error = GET_FPEXC_CTL(current, arg2);
1671 break;
1672 case PR_GET_TIMING:
1673 error = PR_TIMING_STATISTICAL;
1674 break;
1675 case PR_SET_TIMING:
1676 if (arg2 != PR_TIMING_STATISTICAL)
1677 error = -EINVAL;
1678 break;
1679
1680 case PR_SET_NAME: {
1681 struct task_struct *me = current;
1682 unsigned char ncomm[sizeof(me->comm)];
1683
1684 ncomm[sizeof(me->comm)-1] = 0;
1685 if (strncpy_from_user(ncomm, (char __user *)arg2,
1686 sizeof(me->comm)-1) < 0)
1687 return -EFAULT;
1688 set_task_comm(me, ncomm);
1689 return 0;
1690 }
1691 case PR_GET_NAME: {
1692 struct task_struct *me = current;
1693 unsigned char tcomm[sizeof(me->comm)];
1694
1695 get_task_comm(tcomm, me);
1696 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1697 return -EFAULT;
1698 return 0;
1699 }
1700 case PR_GET_ENDIAN:
1701 error = GET_ENDIAN(current, arg2);
1702 break;
1703 case PR_SET_ENDIAN:
1704 error = SET_ENDIAN(current, arg2);
1705 break;
1706
1707 case PR_GET_SECCOMP:
1708 error = prctl_get_seccomp();
1709 break;
1710 case PR_SET_SECCOMP:
1711 error = prctl_set_seccomp(arg2);
1712 break;
1713 case PR_GET_TSC:
1714 error = GET_TSC_CTL(arg2);
1715 break;
1716 case PR_SET_TSC:
1717 error = SET_TSC_CTL(arg2);
1718 break;
1719 case PR_GET_TIMERSLACK:
1720 error = current->timer_slack_ns;
1721 break;
1722 case PR_SET_TIMERSLACK:
1723 if (arg2 <= 0)
1724 current->timer_slack_ns =
1725 current->default_timer_slack_ns;
1726 else
1727 current->timer_slack_ns = arg2;
1728 break;
1729 default:
1730 error = -EINVAL;
1731 break;
1732 }
1733 return error;
1734 }
1735
1736 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1737 struct getcpu_cache __user *unused)
1738 {
1739 int err = 0;
1740 int cpu = raw_smp_processor_id();
1741 if (cpup)
1742 err |= put_user(cpu, cpup);
1743 if (nodep)
1744 err |= put_user(cpu_to_node(cpu), nodep);
1745 return err ? -EFAULT : 0;
1746 }
1747
1748 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1749
1750 static void argv_cleanup(char **argv, char **envp)
1751 {
1752 argv_free(argv);
1753 }
1754
1755 /**
1756 * orderly_poweroff - Trigger an orderly system poweroff
1757 * @force: force poweroff if command execution fails
1758 *
1759 * This may be called from any context to trigger a system shutdown.
1760 * If the orderly shutdown fails, it will force an immediate shutdown.
1761 */
1762 int orderly_poweroff(bool force)
1763 {
1764 int argc;
1765 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1766 static char *envp[] = {
1767 "HOME=/",
1768 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1769 NULL
1770 };
1771 int ret = -ENOMEM;
1772 struct subprocess_info *info;
1773
1774 if (argv == NULL) {
1775 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1776 __func__, poweroff_cmd);
1777 goto out;
1778 }
1779
1780 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1781 if (info == NULL) {
1782 argv_free(argv);
1783 goto out;
1784 }
1785
1786 call_usermodehelper_setcleanup(info, argv_cleanup);
1787
1788 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1789
1790 out:
1791 if (ret && force) {
1792 printk(KERN_WARNING "Failed to start orderly shutdown: "
1793 "forcing the issue\n");
1794
1795 /* I guess this should try to kick off some daemon to
1796 sync and poweroff asap. Or not even bother syncing
1797 if we're doing an emergency shutdown? */
1798 emergency_sync();
1799 kernel_power_off();
1800 }
1801
1802 return ret;
1803 }
1804 EXPORT_SYMBOL_GPL(orderly_poweroff);
CRIS linux kernel tree