projects/linux·blob v2.6.26-rc6 · refs

1822 lines · 42.5 KiB

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
82int overflowuid = DEFAULT_OVERFLOWUID;
83int overflowgid = DEFAULT_OVERFLOWGID;
84
85#ifdef CONFIG_UID16
86EXPORT_SYMBOL(overflowuid);
87EXPORT_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
95int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
96int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
97
98EXPORT_SYMBOL(fs_overflowuid);
99EXPORT_SYMBOL(fs_overflowgid);
100
101/*
102 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
103 */
104
105int C_A_D = 1;
106struct pid *cad_pid;
107EXPORT_SYMBOL(cad_pid);
108
109/*
110 * If set, this is used for preparing the system to power off.
111 */
112
113void (*pm_power_off_prepare)(void);
114
115static 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);
136out:
137 return error;
138}
139
140asmlinkage long sys_setpriority(int which, int who, int niceval)
141{
142 struct task_struct *g, *p;
143 struct user_struct *user;
144 int error = -EINVAL;
145 struct pid *pgrp;
146
147 if (which > PRIO_USER || which < PRIO_PROCESS)
148 goto out;
149
150 /* normalize: avoid signed division (rounding problems) */
151 error = -ESRCH;
152 if (niceval < -20)
153 niceval = -20;
154 if (niceval > 19)
155 niceval = 19;
156
157 read_lock(&tasklist_lock);
158 switch (which) {
159 case PRIO_PROCESS:
160 if (who)
161 p = find_task_by_vpid(who);
162 else
163 p = current;
164 if (p)
165 error = set_one_prio(p, niceval, error);
166 break;
167 case PRIO_PGRP:
168 if (who)
169 pgrp = find_vpid(who);
170 else
171 pgrp = task_pgrp(current);
172 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
175 break;
176 case PRIO_USER:
177 user = current->user;
178 if (!who)
179 who = current->uid;
180 else
181 if ((who != current->uid) && !(user = find_user(who)))
182 goto out_unlock; /* No processes for this user */
183
184 do_each_thread(g, p)
185 if (p->uid == who)
186 error = set_one_prio(p, niceval, error);
187 while_each_thread(g, p);
188 if (who != current->uid)
189 free_uid(user); /* For find_user() */
190 break;
191 }
192out_unlock:
193 read_unlock(&tasklist_lock);
194out:
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 */
204asmlinkage long sys_getpriority(int which, int who)
205{
206 struct task_struct *g, *p;
207 struct user_struct *user;
208 long niceval, retval = -ESRCH;
209 struct pid *pgrp;
210
211 if (which > PRIO_USER || which < PRIO_PROCESS)
212 return -EINVAL;
213
214 read_lock(&tasklist_lock);
215 switch (which) {
216 case PRIO_PROCESS:
217 if (who)
218 p = find_task_by_vpid(who);
219 else
220 p = current;
221 if (p) {
222 niceval = 20 - task_nice(p);
223 if (niceval > retval)
224 retval = niceval;
225 }
226 break;
227 case PRIO_PGRP:
228 if (who)
229 pgrp = find_vpid(who);
230 else
231 pgrp = task_pgrp(current);
232 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
235 retval = niceval;
236 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
237 break;
238 case PRIO_USER:
239 user = current->user;
240 if (!who)
241 who = current->uid;
242 else
243 if ((who != current->uid) && !(user = find_user(who)))
244 goto out_unlock; /* No processes for this user */
245
246 do_each_thread(g, p)
247 if (p->uid == who) {
248 niceval = 20 - task_nice(p);
249 if (niceval > retval)
250 retval = niceval;
251 }
252 while_each_thread(g, p);
253 if (who != current->uid)
254 free_uid(user); /* for find_user() */
255 break;
256 }
257out_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 */
271void emergency_restart(void)
272{
273 machine_emergency_restart();
274}
275EXPORT_SYMBOL_GPL(emergency_restart);
276
277static 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 */
293void 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}
302EXPORT_SYMBOL_GPL(kernel_restart);
303
304/**
305 * kernel_kexec - reboot the system
306 *
307 * Move into place and start executing a preloaded standalone
308 * executable. If nothing was preloaded return an error.
309 */
310static void kernel_kexec(void)
311{
312#ifdef CONFIG_KEXEC
313 struct kimage *image;
314 image = xchg(&kexec_image, NULL);
315 if (!image)
316 return;
317 kernel_restart_prepare(NULL);
318 printk(KERN_EMERG "Starting new kernel\n");
319 machine_shutdown();
320 machine_kexec(image);
321#endif
322}
323
324static void kernel_shutdown_prepare(enum system_states state)
325{
326 blocking_notifier_call_chain(&reboot_notifier_list,
327 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
328 system_state = state;
329 device_shutdown();
330}
331/**
332 * kernel_halt - halt the system
333 *
334 * Shutdown everything and perform a clean system halt.
335 */
336void kernel_halt(void)
337{
338 kernel_shutdown_prepare(SYSTEM_HALT);
339 sysdev_shutdown();
340 printk(KERN_EMERG "System halted.\n");
341 machine_halt();
342}
343
344EXPORT_SYMBOL_GPL(kernel_halt);
345
346/**
347 * kernel_power_off - power_off the system
348 *
349 * Shutdown everything and perform a clean system power_off.
350 */
351void kernel_power_off(void)
352{
353 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
354 if (pm_power_off_prepare)
355 pm_power_off_prepare();
356 disable_nonboot_cpus();
357 sysdev_shutdown();
358 printk(KERN_EMERG "Power down.\n");
359 machine_power_off();
360}
361EXPORT_SYMBOL_GPL(kernel_power_off);
362/*
363 * Reboot system call: for obvious reasons only root may call it,
364 * and even root needs to set up some magic numbers in the registers
365 * so that some mistake won't make this reboot the whole machine.
366 * You can also set the meaning of the ctrl-alt-del-key here.
367 *
368 * reboot doesn't sync: do that yourself before calling this.
369 */
370asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
371{
372 char buffer[256];
373
374 /* We only trust the superuser with rebooting the system. */
375 if (!capable(CAP_SYS_BOOT))
376 return -EPERM;
377
378 /* For safety, we require "magic" arguments. */
379 if (magic1 != LINUX_REBOOT_MAGIC1 ||
380 (magic2 != LINUX_REBOOT_MAGIC2 &&
381 magic2 != LINUX_REBOOT_MAGIC2A &&
382 magic2 != LINUX_REBOOT_MAGIC2B &&
383 magic2 != LINUX_REBOOT_MAGIC2C))
384 return -EINVAL;
385
386 /* Instead of trying to make the power_off code look like
387 * halt when pm_power_off is not set do it the easy way.
388 */
389 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
390 cmd = LINUX_REBOOT_CMD_HALT;
391
392 lock_kernel();
393 switch (cmd) {
394 case LINUX_REBOOT_CMD_RESTART:
395 kernel_restart(NULL);
396 break;
397
398 case LINUX_REBOOT_CMD_CAD_ON:
399 C_A_D = 1;
400 break;
401
402 case LINUX_REBOOT_CMD_CAD_OFF:
403 C_A_D = 0;
404 break;
405
406 case LINUX_REBOOT_CMD_HALT:
407 kernel_halt();
408 unlock_kernel();
409 do_exit(0);
410 break;
411
412 case LINUX_REBOOT_CMD_POWER_OFF:
413 kernel_power_off();
414 unlock_kernel();
415 do_exit(0);
416 break;
417
418 case LINUX_REBOOT_CMD_RESTART2:
419 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
420 unlock_kernel();
421 return -EFAULT;
422 }
423 buffer[sizeof(buffer) - 1] = '\0';
424
425 kernel_restart(buffer);
426 break;
427
428 case LINUX_REBOOT_CMD_KEXEC:
429 kernel_kexec();
430 unlock_kernel();
431 return -EINVAL;
432
433#ifdef CONFIG_HIBERNATION
434 case LINUX_REBOOT_CMD_SW_SUSPEND:
435 {
436 int ret = hibernate();
437 unlock_kernel();
438 return ret;
439 }
440#endif
441
442 default:
443 unlock_kernel();
444 return -EINVAL;
445 }
446 unlock_kernel();
447 return 0;
448}
449
450static void deferred_cad(struct work_struct *dummy)
451{
452 kernel_restart(NULL);
453}
454
455/*
456 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
457 * As it's called within an interrupt, it may NOT sync: the only choice
458 * is whether to reboot at once, or just ignore the ctrl-alt-del.
459 */
460void ctrl_alt_del(void)
461{
462 static DECLARE_WORK(cad_work, deferred_cad);
463
464 if (C_A_D)
465 schedule_work(&cad_work);
466 else
467 kill_cad_pid(SIGINT, 1);
468}
469
470/*
471 * Unprivileged users may change the real gid to the effective gid
472 * or vice versa. (BSD-style)
473 *
474 * If you set the real gid at all, or set the effective gid to a value not
475 * equal to the real gid, then the saved gid is set to the new effective gid.
476 *
477 * This makes it possible for a setgid program to completely drop its
478 * privileges, which is often a useful assertion to make when you are doing
479 * a security audit over a program.
480 *
481 * The general idea is that a program which uses just setregid() will be
482 * 100% compatible with BSD. A program which uses just setgid() will be
483 * 100% compatible with POSIX with saved IDs.
484 *
485 * SMP: There are not races, the GIDs are checked only by filesystem
486 * operations (as far as semantic preservation is concerned).
487 */
488asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
489{
490 int old_rgid = current->gid;
491 int old_egid = current->egid;
492 int new_rgid = old_rgid;
493 int new_egid = old_egid;
494 int retval;
495
496 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
497 if (retval)
498 return retval;
499
500 if (rgid != (gid_t) -1) {
501 if ((old_rgid == rgid) ||
502 (current->egid==rgid) ||
503 capable(CAP_SETGID))
504 new_rgid = rgid;
505 else
506 return -EPERM;
507 }
508 if (egid != (gid_t) -1) {
509 if ((old_rgid == egid) ||
510 (current->egid == egid) ||
511 (current->sgid == egid) ||
512 capable(CAP_SETGID))
513 new_egid = egid;
514 else
515 return -EPERM;
516 }
517 if (new_egid != old_egid) {
518 set_dumpable(current->mm, suid_dumpable);
519 smp_wmb();
520 }
521 if (rgid != (gid_t) -1 ||
522 (egid != (gid_t) -1 && egid != old_rgid))
523 current->sgid = new_egid;
524 current->fsgid = new_egid;
525 current->egid = new_egid;
526 current->gid = new_rgid;
527 key_fsgid_changed(current);
528 proc_id_connector(current, PROC_EVENT_GID);
529 return 0;
530}
531
532/*
533 * setgid() is implemented like SysV w/ SAVED_IDS
534 *
535 * SMP: Same implicit races as above.
536 */
537asmlinkage long sys_setgid(gid_t gid)
538{
539 int old_egid = current->egid;
540 int retval;
541
542 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
543 if (retval)
544 return retval;
545
546 if (capable(CAP_SETGID)) {
547 if (old_egid != gid) {
548 set_dumpable(current->mm, suid_dumpable);
549 smp_wmb();
550 }
551 current->gid = current->egid = current->sgid = current->fsgid = gid;
552 } else if ((gid == current->gid) || (gid == current->sgid)) {
553 if (old_egid != gid) {
554 set_dumpable(current->mm, suid_dumpable);
555 smp_wmb();
556 }
557 current->egid = current->fsgid = gid;
558 }
559 else
560 return -EPERM;
561
562 key_fsgid_changed(current);
563 proc_id_connector(current, PROC_EVENT_GID);
564 return 0;
565}
566
567static int set_user(uid_t new_ruid, int dumpclear)
568{
569 struct user_struct *new_user;
570
571 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
572 if (!new_user)
573 return -EAGAIN;
574
575 if (atomic_read(&new_user->processes) >=
576 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
577 new_user != current->nsproxy->user_ns->root_user) {
578 free_uid(new_user);
579 return -EAGAIN;
580 }
581
582 switch_uid(new_user);
583
584 if (dumpclear) {
585 set_dumpable(current->mm, suid_dumpable);
586 smp_wmb();
587 }
588 current->uid = new_ruid;
589 return 0;
590}
591
592/*
593 * Unprivileged users may change the real uid to the effective uid
594 * or vice versa. (BSD-style)
595 *
596 * If you set the real uid at all, or set the effective uid to a value not
597 * equal to the real uid, then the saved uid is set to the new effective uid.
598 *
599 * This makes it possible for a setuid program to completely drop its
600 * privileges, which is often a useful assertion to make when you are doing
601 * a security audit over a program.
602 *
603 * The general idea is that a program which uses just setreuid() will be
604 * 100% compatible with BSD. A program which uses just setuid() will be
605 * 100% compatible with POSIX with saved IDs.
606 */
607asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
608{
609 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
610 int retval;
611
612 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
613 if (retval)
614 return retval;
615
616 new_ruid = old_ruid = current->uid;
617 new_euid = old_euid = current->euid;
618 old_suid = current->suid;
619
620 if (ruid != (uid_t) -1) {
621 new_ruid = ruid;
622 if ((old_ruid != ruid) &&
623 (current->euid != ruid) &&
624 !capable(CAP_SETUID))
625 return -EPERM;
626 }
627
628 if (euid != (uid_t) -1) {
629 new_euid = euid;
630 if ((old_ruid != euid) &&
631 (current->euid != euid) &&
632 (current->suid != euid) &&
633 !capable(CAP_SETUID))
634 return -EPERM;
635 }
636
637 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
638 return -EAGAIN;
639
640 if (new_euid != old_euid) {
641 set_dumpable(current->mm, suid_dumpable);
642 smp_wmb();
643 }
644 current->fsuid = current->euid = new_euid;
645 if (ruid != (uid_t) -1 ||
646 (euid != (uid_t) -1 && euid != old_ruid))
647 current->suid = current->euid;
648 current->fsuid = current->euid;
649
650 key_fsuid_changed(current);
651 proc_id_connector(current, PROC_EVENT_UID);
652
653 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
654}
655
656
657
658/*
659 * setuid() is implemented like SysV with SAVED_IDS
660 *
661 * Note that SAVED_ID's is deficient in that a setuid root program
662 * like sendmail, for example, cannot set its uid to be a normal
663 * user and then switch back, because if you're root, setuid() sets
664 * the saved uid too. If you don't like this, blame the bright people
665 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
666 * will allow a root program to temporarily drop privileges and be able to
667 * regain them by swapping the real and effective uid.
668 */
669asmlinkage long sys_setuid(uid_t uid)
670{
671 int old_euid = current->euid;
672 int old_ruid, old_suid, new_suid;
673 int retval;
674
675 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
676 if (retval)
677 return retval;
678
679 old_ruid = current->uid;
680 old_suid = current->suid;
681 new_suid = old_suid;
682
683 if (capable(CAP_SETUID)) {
684 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
685 return -EAGAIN;
686 new_suid = uid;
687 } else if ((uid != current->uid) && (uid != new_suid))
688 return -EPERM;
689
690 if (old_euid != uid) {
691 set_dumpable(current->mm, suid_dumpable);
692 smp_wmb();
693 }
694 current->fsuid = current->euid = uid;
695 current->suid = new_suid;
696
697 key_fsuid_changed(current);
698 proc_id_connector(current, PROC_EVENT_UID);
699
700 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
701}
702
703
704/*
705 * This function implements a generic ability to update ruid, euid,
706 * and suid. This allows you to implement the 4.4 compatible seteuid().
707 */
708asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
709{
710 int old_ruid = current->uid;
711 int old_euid = current->euid;
712 int old_suid = current->suid;
713 int retval;
714
715 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
716 if (retval)
717 return retval;
718
719 if (!capable(CAP_SETUID)) {
720 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
721 (ruid != current->euid) && (ruid != current->suid))
722 return -EPERM;
723 if ((euid != (uid_t) -1) && (euid != current->uid) &&
724 (euid != current->euid) && (euid != current->suid))
725 return -EPERM;
726 if ((suid != (uid_t) -1) && (suid != current->uid) &&
727 (suid != current->euid) && (suid != current->suid))
728 return -EPERM;
729 }
730 if (ruid != (uid_t) -1) {
731 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
732 return -EAGAIN;
733 }
734 if (euid != (uid_t) -1) {
735 if (euid != current->euid) {
736 set_dumpable(current->mm, suid_dumpable);
737 smp_wmb();
738 }
739 current->euid = euid;
740 }
741 current->fsuid = current->euid;
742 if (suid != (uid_t) -1)
743 current->suid = suid;
744
745 key_fsuid_changed(current);
746 proc_id_connector(current, PROC_EVENT_UID);
747
748 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
749}
750
751asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
752{
753 int retval;
754
755 if (!(retval = put_user(current->uid, ruid)) &&
756 !(retval = put_user(current->euid, euid)))
757 retval = put_user(current->suid, suid);
758
759 return retval;
760}
761
762/*
763 * Same as above, but for rgid, egid, sgid.
764 */
765asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
766{
767 int retval;
768
769 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
770 if (retval)
771 return retval;
772
773 if (!capable(CAP_SETGID)) {
774 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
775 (rgid != current->egid) && (rgid != current->sgid))
776 return -EPERM;
777 if ((egid != (gid_t) -1) && (egid != current->gid) &&
778 (egid != current->egid) && (egid != current->sgid))
779 return -EPERM;
780 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
781 (sgid != current->egid) && (sgid != current->sgid))
782 return -EPERM;
783 }
784 if (egid != (gid_t) -1) {
785 if (egid != current->egid) {
786 set_dumpable(current->mm, suid_dumpable);
787 smp_wmb();
788 }
789 current->egid = egid;
790 }
791 current->fsgid = current->egid;
792 if (rgid != (gid_t) -1)
793 current->gid = rgid;
794 if (sgid != (gid_t) -1)
795 current->sgid = sgid;
796
797 key_fsgid_changed(current);
798 proc_id_connector(current, PROC_EVENT_GID);
799 return 0;
800}
801
802asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
803{
804 int retval;
805
806 if (!(retval = put_user(current->gid, rgid)) &&
807 !(retval = put_user(current->egid, egid)))
808 retval = put_user(current->sgid, sgid);
809
810 return retval;
811}
812
813
814/*
815 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
816 * is used for "access()" and for the NFS daemon (letting nfsd stay at
817 * whatever uid it wants to). It normally shadows "euid", except when
818 * explicitly set by setfsuid() or for access..
819 */
820asmlinkage long sys_setfsuid(uid_t uid)
821{
822 int old_fsuid;
823
824 old_fsuid = current->fsuid;
825 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
826 return old_fsuid;
827
828 if (uid == current->uid || uid == current->euid ||
829 uid == current->suid || uid == current->fsuid ||
830 capable(CAP_SETUID)) {
831 if (uid != old_fsuid) {
832 set_dumpable(current->mm, suid_dumpable);
833 smp_wmb();
834 }
835 current->fsuid = uid;
836 }
837
838 key_fsuid_changed(current);
839 proc_id_connector(current, PROC_EVENT_UID);
840
841 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
842
843 return old_fsuid;
844}
845
846/*
847 * Samma på svenska..
848 */
849asmlinkage long sys_setfsgid(gid_t gid)
850{
851 int old_fsgid;
852
853 old_fsgid = current->fsgid;
854 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
855 return old_fsgid;
856
857 if (gid == current->gid || gid == current->egid ||
858 gid == current->sgid || gid == current->fsgid ||
859 capable(CAP_SETGID)) {
860 if (gid != old_fsgid) {
861 set_dumpable(current->mm, suid_dumpable);
862 smp_wmb();
863 }
864 current->fsgid = gid;
865 key_fsgid_changed(current);
866 proc_id_connector(current, PROC_EVENT_GID);
867 }
868 return old_fsgid;
869}
870
871asmlinkage long sys_times(struct tms __user * tbuf)
872{
873 /*
874 * In the SMP world we might just be unlucky and have one of
875 * the times increment as we use it. Since the value is an
876 * atomically safe type this is just fine. Conceptually its
877 * as if the syscall took an instant longer to occur.
878 */
879 if (tbuf) {
880 struct tms tmp;
881 struct task_struct *tsk = current;
882 struct task_struct *t;
883 cputime_t utime, stime, cutime, cstime;
884
885 spin_lock_irq(&tsk->sighand->siglock);
886 utime = tsk->signal->utime;
887 stime = tsk->signal->stime;
888 t = tsk;
889 do {
890 utime = cputime_add(utime, t->utime);
891 stime = cputime_add(stime, t->stime);
892 t = next_thread(t);
893 } while (t != tsk);
894
895 cutime = tsk->signal->cutime;
896 cstime = tsk->signal->cstime;
897 spin_unlock_irq(&tsk->sighand->siglock);
898
899 tmp.tms_utime = cputime_to_clock_t(utime);
900 tmp.tms_stime = cputime_to_clock_t(stime);
901 tmp.tms_cutime = cputime_to_clock_t(cutime);
902 tmp.tms_cstime = cputime_to_clock_t(cstime);
903 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
904 return -EFAULT;
905 }
906 return (long) jiffies_64_to_clock_t(get_jiffies_64());
907}
908
909/*
910 * This needs some heavy checking ...
911 * I just haven't the stomach for it. I also don't fully
912 * understand sessions/pgrp etc. Let somebody who does explain it.
913 *
914 * OK, I think I have the protection semantics right.... this is really
915 * only important on a multi-user system anyway, to make sure one user
916 * can't send a signal to a process owned by another. -TYT, 12/12/91
917 *
918 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
919 * LBT 04.03.94
920 */
921asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
922{
923 struct task_struct *p;
924 struct task_struct *group_leader = current->group_leader;
925 struct pid *pgrp;
926 int err;
927
928 if (!pid)
929 pid = task_pid_vnr(group_leader);
930 if (!pgid)
931 pgid = pid;
932 if (pgid < 0)
933 return -EINVAL;
934
935 /* From this point forward we keep holding onto the tasklist lock
936 * so that our parent does not change from under us. -DaveM
937 */
938 write_lock_irq(&tasklist_lock);
939
940 err = -ESRCH;
941 p = find_task_by_vpid(pid);
942 if (!p)
943 goto out;
944
945 err = -EINVAL;
946 if (!thread_group_leader(p))
947 goto out;
948
949 if (same_thread_group(p->real_parent, group_leader)) {
950 err = -EPERM;
951 if (task_session(p) != task_session(group_leader))
952 goto out;
953 err = -EACCES;
954 if (p->did_exec)
955 goto out;
956 } else {
957 err = -ESRCH;
958 if (p != group_leader)
959 goto out;
960 }
961
962 err = -EPERM;
963 if (p->signal->leader)
964 goto out;
965
966 pgrp = task_pid(p);
967 if (pgid != pid) {
968 struct task_struct *g;
969
970 pgrp = find_vpid(pgid);
971 g = pid_task(pgrp, PIDTYPE_PGID);
972 if (!g || task_session(g) != task_session(group_leader))
973 goto out;
974 }
975
976 err = security_task_setpgid(p, pgid);
977 if (err)
978 goto out;
979
980 if (task_pgrp(p) != pgrp) {
981 change_pid(p, PIDTYPE_PGID, pgrp);
982 set_task_pgrp(p, pid_nr(pgrp));
983 }
984
985 err = 0;
986out:
987 /* All paths lead to here, thus we are safe. -DaveM */
988 write_unlock_irq(&tasklist_lock);
989 return err;
990}
991
992asmlinkage long sys_getpgid(pid_t pid)
993{
994 struct task_struct *p;
995 struct pid *grp;
996 int retval;
997
998 rcu_read_lock();
999 if (!pid)
1000 grp = task_pgrp(current);
1001 else {
1002 retval = -ESRCH;
1003 p = find_task_by_vpid(pid);
1004 if (!p)
1005 goto out;
1006 grp = task_pgrp(p);
1007 if (!grp)
1008 goto out;
1009
1010 retval = security_task_getpgid(p);
1011 if (retval)
1012 goto out;
1013 }
1014 retval = pid_vnr(grp);
1015out:
1016 rcu_read_unlock();
1017 return retval;
1018}
1019
1020#ifdef __ARCH_WANT_SYS_GETPGRP
1021
1022asmlinkage long sys_getpgrp(void)
1023{
1024 return sys_getpgid(0);
1025}
1026
1027#endif
1028
1029asmlinkage long sys_getsid(pid_t pid)
1030{
1031 struct task_struct *p;
1032 struct pid *sid;
1033 int retval;
1034
1035 rcu_read_lock();
1036 if (!pid)
1037 sid = task_session(current);
1038 else {
1039 retval = -ESRCH;
1040 p = find_task_by_vpid(pid);
1041 if (!p)
1042 goto out;
1043 sid = task_session(p);
1044 if (!sid)
1045 goto out;
1046
1047 retval = security_task_getsid(p);
1048 if (retval)
1049 goto out;
1050 }
1051 retval = pid_vnr(sid);
1052out:
1053 rcu_read_unlock();
1054 return retval;
1055}
1056
1057asmlinkage long sys_setsid(void)
1058{
1059 struct task_struct *group_leader = current->group_leader;
1060 struct pid *sid = task_pid(group_leader);
1061 pid_t session = pid_vnr(sid);
1062 int err = -EPERM;
1063
1064 write_lock_irq(&tasklist_lock);
1065 /* Fail if I am already a session leader */
1066 if (group_leader->signal->leader)
1067 goto out;
1068
1069 /* Fail if a process group id already exists that equals the
1070 * proposed session id.
1071 */
1072 if (pid_task(sid, PIDTYPE_PGID))
1073 goto out;
1074
1075 group_leader->signal->leader = 1;
1076 __set_special_pids(sid);
1077
1078 spin_lock(&group_leader->sighand->siglock);
1079 group_leader->signal->tty = NULL;
1080 spin_unlock(&group_leader->sighand->siglock);
1081
1082 err = session;
1083out:
1084 write_unlock_irq(&tasklist_lock);
1085 return err;
1086}
1087
1088/*
1089 * Supplementary group IDs
1090 */
1091
1092/* init to 2 - one for init_task, one to ensure it is never freed */
1093struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1094
1095struct group_info *groups_alloc(int gidsetsize)
1096{
1097 struct group_info *group_info;
1098 int nblocks;
1099 int i;
1100
1101 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1102 /* Make sure we always allocate at least one indirect block pointer */
1103 nblocks = nblocks ? : 1;
1104 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1105 if (!group_info)
1106 return NULL;
1107 group_info->ngroups = gidsetsize;
1108 group_info->nblocks = nblocks;
1109 atomic_set(&group_info->usage, 1);
1110
1111 if (gidsetsize <= NGROUPS_SMALL)
1112 group_info->blocks[0] = group_info->small_block;
1113 else {
1114 for (i = 0; i < nblocks; i++) {
1115 gid_t *b;
1116 b = (void *)__get_free_page(GFP_USER);
1117 if (!b)
1118 goto out_undo_partial_alloc;
1119 group_info->blocks[i] = b;
1120 }
1121 }
1122 return group_info;
1123
1124out_undo_partial_alloc:
1125 while (--i >= 0) {
1126 free_page((unsigned long)group_info->blocks[i]);
1127 }
1128 kfree(group_info);
1129 return NULL;
1130}
1131
1132EXPORT_SYMBOL(groups_alloc);
1133
1134void groups_free(struct group_info *group_info)
1135{
1136 if (group_info->blocks[0] != group_info->small_block) {
1137 int i;
1138 for (i = 0; i < group_info->nblocks; i++)
1139 free_page((unsigned long)group_info->blocks[i]);
1140 }
1141 kfree(group_info);
1142}
1143
1144EXPORT_SYMBOL(groups_free);
1145
1146/* export the group_info to a user-space array */
1147static int groups_to_user(gid_t __user *grouplist,
1148 struct group_info *group_info)
1149{
1150 int i;
1151 unsigned int count = group_info->ngroups;
1152
1153 for (i = 0; i < group_info->nblocks; i++) {
1154 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1155 unsigned int len = cp_count * sizeof(*grouplist);
1156
1157 if (copy_to_user(grouplist, group_info->blocks[i], len))
1158 return -EFAULT;
1159
1160 grouplist += NGROUPS_PER_BLOCK;
1161 count -= cp_count;
1162 }
1163 return 0;
1164}
1165
1166/* fill a group_info from a user-space array - it must be allocated already */
1167static int groups_from_user(struct group_info *group_info,
1168 gid_t __user *grouplist)
1169{
1170 int i;
1171 unsigned int count = group_info->ngroups;
1172
1173 for (i = 0; i < group_info->nblocks; i++) {
1174 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1175 unsigned int len = cp_count * sizeof(*grouplist);
1176
1177 if (copy_from_user(group_info->blocks[i], grouplist, len))
1178 return -EFAULT;
1179
1180 grouplist += NGROUPS_PER_BLOCK;
1181 count -= cp_count;
1182 }
1183 return 0;
1184}
1185
1186/* a simple Shell sort */
1187static void groups_sort(struct group_info *group_info)
1188{
1189 int base, max, stride;
1190 int gidsetsize = group_info->ngroups;
1191
1192 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1193 ; /* nothing */
1194 stride /= 3;
1195
1196 while (stride) {
1197 max = gidsetsize - stride;
1198 for (base = 0; base < max; base++) {
1199 int left = base;
1200 int right = left + stride;
1201 gid_t tmp = GROUP_AT(group_info, right);
1202
1203 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1204 GROUP_AT(group_info, right) =
1205 GROUP_AT(group_info, left);
1206 right = left;
1207 left -= stride;
1208 }
1209 GROUP_AT(group_info, right) = tmp;
1210 }
1211 stride /= 3;
1212 }
1213}
1214
1215/* a simple bsearch */
1216int groups_search(struct group_info *group_info, gid_t grp)
1217{
1218 unsigned int left, right;
1219
1220 if (!group_info)
1221 return 0;
1222
1223 left = 0;
1224 right = group_info->ngroups;
1225 while (left < right) {
1226 unsigned int mid = (left+right)/2;
1227 int cmp = grp - GROUP_AT(group_info, mid);
1228 if (cmp > 0)
1229 left = mid + 1;
1230 else if (cmp < 0)
1231 right = mid;
1232 else
1233 return 1;
1234 }
1235 return 0;
1236}
1237
1238/* validate and set current->group_info */
1239int set_current_groups(struct group_info *group_info)
1240{
1241 int retval;
1242 struct group_info *old_info;
1243
1244 retval = security_task_setgroups(group_info);
1245 if (retval)
1246 return retval;
1247
1248 groups_sort(group_info);
1249 get_group_info(group_info);
1250
1251 task_lock(current);
1252 old_info = current->group_info;
1253 current->group_info = group_info;
1254 task_unlock(current);
1255
1256 put_group_info(old_info);
1257
1258 return 0;
1259}
1260
1261EXPORT_SYMBOL(set_current_groups);
1262
1263asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1264{
1265 int i = 0;
1266
1267 /*
1268 * SMP: Nobody else can change our grouplist. Thus we are
1269 * safe.
1270 */
1271
1272 if (gidsetsize < 0)
1273 return -EINVAL;
1274
1275 /* no need to grab task_lock here; it cannot change */
1276 i = current->group_info->ngroups;
1277 if (gidsetsize) {
1278 if (i > gidsetsize) {
1279 i = -EINVAL;
1280 goto out;
1281 }
1282 if (groups_to_user(grouplist, current->group_info)) {
1283 i = -EFAULT;
1284 goto out;
1285 }
1286 }
1287out:
1288 return i;
1289}
1290
1291/*
1292 * SMP: Our groups are copy-on-write. We can set them safely
1293 * without another task interfering.
1294 */
1295
1296asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1297{
1298 struct group_info *group_info;
1299 int retval;
1300
1301 if (!capable(CAP_SETGID))
1302 return -EPERM;
1303 if ((unsigned)gidsetsize > NGROUPS_MAX)
1304 return -EINVAL;
1305
1306 group_info = groups_alloc(gidsetsize);
1307 if (!group_info)
1308 return -ENOMEM;
1309 retval = groups_from_user(group_info, grouplist);
1310 if (retval) {
1311 put_group_info(group_info);
1312 return retval;
1313 }
1314
1315 retval = set_current_groups(group_info);
1316 put_group_info(group_info);
1317
1318 return retval;
1319}
1320
1321/*
1322 * Check whether we're fsgid/egid or in the supplemental group..
1323 */
1324int in_group_p(gid_t grp)
1325{
1326 int retval = 1;
1327 if (grp != current->fsgid)
1328 retval = groups_search(current->group_info, grp);
1329 return retval;
1330}
1331
1332EXPORT_SYMBOL(in_group_p);
1333
1334int in_egroup_p(gid_t grp)
1335{
1336 int retval = 1;
1337 if (grp != current->egid)
1338 retval = groups_search(current->group_info, grp);
1339 return retval;
1340}
1341
1342EXPORT_SYMBOL(in_egroup_p);
1343
1344DECLARE_RWSEM(uts_sem);
1345
1346EXPORT_SYMBOL(uts_sem);
1347
1348asmlinkage long sys_newuname(struct new_utsname __user * name)
1349{
1350 int errno = 0;
1351
1352 down_read(&uts_sem);
1353 if (copy_to_user(name, utsname(), sizeof *name))
1354 errno = -EFAULT;
1355 up_read(&uts_sem);
1356 return errno;
1357}
1358
1359asmlinkage long sys_sethostname(char __user *name, int len)
1360{
1361 int errno;
1362 char tmp[__NEW_UTS_LEN];
1363
1364 if (!capable(CAP_SYS_ADMIN))
1365 return -EPERM;
1366 if (len < 0 || len > __NEW_UTS_LEN)
1367 return -EINVAL;
1368 down_write(&uts_sem);
1369 errno = -EFAULT;
1370 if (!copy_from_user(tmp, name, len)) {
1371 memcpy(utsname()->nodename, tmp, len);
1372 utsname()->nodename[len] = 0;
1373 errno = 0;
1374 }
1375 up_write(&uts_sem);
1376 return errno;
1377}
1378
1379#ifdef __ARCH_WANT_SYS_GETHOSTNAME
1380
1381asmlinkage long sys_gethostname(char __user *name, int len)
1382{
1383 int i, errno;
1384
1385 if (len < 0)
1386 return -EINVAL;
1387 down_read(&uts_sem);
1388 i = 1 + strlen(utsname()->nodename);
1389 if (i > len)
1390 i = len;
1391 errno = 0;
1392 if (copy_to_user(name, utsname()->nodename, i))
1393 errno = -EFAULT;
1394 up_read(&uts_sem);
1395 return errno;
1396}
1397
1398#endif
1399
1400/*
1401 * Only setdomainname; getdomainname can be implemented by calling
1402 * uname()
1403 */
1404asmlinkage long sys_setdomainname(char __user *name, int len)
1405{
1406 int errno;
1407 char tmp[__NEW_UTS_LEN];
1408
1409 if (!capable(CAP_SYS_ADMIN))
1410 return -EPERM;
1411 if (len < 0 || len > __NEW_UTS_LEN)
1412 return -EINVAL;
1413
1414 down_write(&uts_sem);
1415 errno = -EFAULT;
1416 if (!copy_from_user(tmp, name, len)) {
1417 memcpy(utsname()->domainname, tmp, len);
1418 utsname()->domainname[len] = 0;
1419 errno = 0;
1420 }
1421 up_write(&uts_sem);
1422 return errno;
1423}
1424
1425asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1426{
1427 if (resource >= RLIM_NLIMITS)
1428 return -EINVAL;
1429 else {
1430 struct rlimit value;
1431 task_lock(current->group_leader);
1432 value = current->signal->rlim[resource];
1433 task_unlock(current->group_leader);
1434 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1435 }
1436}
1437
1438#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1439
1440/*
1441 * Back compatibility for getrlimit. Needed for some apps.
1442 */
1443
1444asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1445{
1446 struct rlimit x;
1447 if (resource >= RLIM_NLIMITS)
1448 return -EINVAL;
1449
1450 task_lock(current->group_leader);
1451 x = current->signal->rlim[resource];
1452 task_unlock(current->group_leader);
1453 if (x.rlim_cur > 0x7FFFFFFF)
1454 x.rlim_cur = 0x7FFFFFFF;
1455 if (x.rlim_max > 0x7FFFFFFF)
1456 x.rlim_max = 0x7FFFFFFF;
1457 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1458}
1459
1460#endif
1461
1462asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1463{
1464 struct rlimit new_rlim, *old_rlim;
1465 unsigned long it_prof_secs;
1466 int retval;
1467
1468 if (resource >= RLIM_NLIMITS)
1469 return -EINVAL;
1470 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1471 return -EFAULT;
1472 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1473 return -EINVAL;
1474 old_rlim = current->signal->rlim + resource;
1475 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1476 !capable(CAP_SYS_RESOURCE))
1477 return -EPERM;
1478 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1479 return -EPERM;
1480
1481 retval = security_task_setrlimit(resource, &new_rlim);
1482 if (retval)
1483 return retval;
1484
1485 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1486 /*
1487 * The caller is asking for an immediate RLIMIT_CPU
1488 * expiry. But we use the zero value to mean "it was
1489 * never set". So let's cheat and make it one second
1490 * instead
1491 */
1492 new_rlim.rlim_cur = 1;
1493 }
1494
1495 task_lock(current->group_leader);
1496 *old_rlim = new_rlim;
1497 task_unlock(current->group_leader);
1498
1499 if (resource != RLIMIT_CPU)
1500 goto out;
1501
1502 /*
1503 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1504 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1505 * very long-standing error, and fixing it now risks breakage of
1506 * applications, so we live with it
1507 */
1508 if (new_rlim.rlim_cur == RLIM_INFINITY)
1509 goto out;
1510
1511 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1512 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1513 unsigned long rlim_cur = new_rlim.rlim_cur;
1514 cputime_t cputime;
1515
1516 cputime = secs_to_cputime(rlim_cur);
1517 read_lock(&tasklist_lock);
1518 spin_lock_irq(&current->sighand->siglock);
1519 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1520 spin_unlock_irq(&current->sighand->siglock);
1521 read_unlock(&tasklist_lock);
1522 }
1523out:
1524 return 0;
1525}
1526
1527/*
1528 * It would make sense to put struct rusage in the task_struct,
1529 * except that would make the task_struct be *really big*. After
1530 * task_struct gets moved into malloc'ed memory, it would
1531 * make sense to do this. It will make moving the rest of the information
1532 * a lot simpler! (Which we're not doing right now because we're not
1533 * measuring them yet).
1534 *
1535 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1536 * races with threads incrementing their own counters. But since word
1537 * reads are atomic, we either get new values or old values and we don't
1538 * care which for the sums. We always take the siglock to protect reading
1539 * the c* fields from p->signal from races with exit.c updating those
1540 * fields when reaping, so a sample either gets all the additions of a
1541 * given child after it's reaped, or none so this sample is before reaping.
1542 *
1543 * Locking:
1544 * We need to take the siglock for CHILDEREN, SELF and BOTH
1545 * for the cases current multithreaded, non-current single threaded
1546 * non-current multithreaded. Thread traversal is now safe with
1547 * the siglock held.
1548 * Strictly speaking, we donot need to take the siglock if we are current and
1549 * single threaded, as no one else can take our signal_struct away, no one
1550 * else can reap the children to update signal->c* counters, and no one else
1551 * can race with the signal-> fields. If we do not take any lock, the
1552 * signal-> fields could be read out of order while another thread was just
1553 * exiting. So we should place a read memory barrier when we avoid the lock.
1554 * On the writer side, write memory barrier is implied in __exit_signal
1555 * as __exit_signal releases the siglock spinlock after updating the signal->
1556 * fields. But we don't do this yet to keep things simple.
1557 *
1558 */
1559
1560static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
1561 cputime_t *utimep, cputime_t *stimep)
1562{
1563 *utimep = cputime_add(*utimep, t->utime);
1564 *stimep = cputime_add(*stimep, t->stime);
1565 r->ru_nvcsw += t->nvcsw;
1566 r->ru_nivcsw += t->nivcsw;
1567 r->ru_minflt += t->min_flt;
1568 r->ru_majflt += t->maj_flt;
1569 r->ru_inblock += task_io_get_inblock(t);
1570 r->ru_oublock += task_io_get_oublock(t);
1571}
1572
1573static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1574{
1575 struct task_struct *t;
1576 unsigned long flags;
1577 cputime_t utime, stime;
1578
1579 memset((char *) r, 0, sizeof *r);
1580 utime = stime = cputime_zero;
1581
1582 if (who == RUSAGE_THREAD) {
1583 accumulate_thread_rusage(p, r, &utime, &stime);
1584 goto out;
1585 }
1586
1587 if (!lock_task_sighand(p, &flags))
1588 return;
1589
1590 switch (who) {
1591 case RUSAGE_BOTH:
1592 case RUSAGE_CHILDREN:
1593 utime = p->signal->cutime;
1594 stime = p->signal->cstime;
1595 r->ru_nvcsw = p->signal->cnvcsw;
1596 r->ru_nivcsw = p->signal->cnivcsw;
1597 r->ru_minflt = p->signal->cmin_flt;
1598 r->ru_majflt = p->signal->cmaj_flt;
1599 r->ru_inblock = p->signal->cinblock;
1600 r->ru_oublock = p->signal->coublock;
1601
1602 if (who == RUSAGE_CHILDREN)
1603 break;
1604
1605 case RUSAGE_SELF:
1606 utime = cputime_add(utime, p->signal->utime);
1607 stime = cputime_add(stime, p->signal->stime);
1608 r->ru_nvcsw += p->signal->nvcsw;
1609 r->ru_nivcsw += p->signal->nivcsw;
1610 r->ru_minflt += p->signal->min_flt;
1611 r->ru_majflt += p->signal->maj_flt;
1612 r->ru_inblock += p->signal->inblock;
1613 r->ru_oublock += p->signal->oublock;
1614 t = p;
1615 do {
1616 accumulate_thread_rusage(t, r, &utime, &stime);
1617 t = next_thread(t);
1618 } while (t != p);
1619 break;
1620
1621 default:
1622 BUG();
1623 }
1624 unlock_task_sighand(p, &flags);
1625
1626out:
1627 cputime_to_timeval(utime, &r->ru_utime);
1628 cputime_to_timeval(stime, &r->ru_stime);
1629}
1630
1631int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1632{
1633 struct rusage r;
1634 k_getrusage(p, who, &r);
1635 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1636}
1637
1638asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1639{
1640 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1641 who != RUSAGE_THREAD)
1642 return -EINVAL;
1643 return getrusage(current, who, ru);
1644}
1645
1646asmlinkage long sys_umask(int mask)
1647{
1648 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1649 return mask;
1650}
1651
1652asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1653 unsigned long arg4, unsigned long arg5)
1654{
1655 long error = 0;
1656
1657 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1658 return error;
1659
1660 switch (option) {
1661 case PR_SET_PDEATHSIG:
1662 if (!valid_signal(arg2)) {
1663 error = -EINVAL;
1664 break;
1665 }
1666 current->pdeath_signal = arg2;
1667 break;
1668 case PR_GET_PDEATHSIG:
1669 error = put_user(current->pdeath_signal, (int __user *)arg2);
1670 break;
1671 case PR_GET_DUMPABLE:
1672 error = get_dumpable(current->mm);
1673 break;
1674 case PR_SET_DUMPABLE:
1675 if (arg2 < 0 || arg2 > 1) {
1676 error = -EINVAL;
1677 break;
1678 }
1679 set_dumpable(current->mm, arg2);
1680 break;
1681
1682 case PR_SET_UNALIGN:
1683 error = SET_UNALIGN_CTL(current, arg2);
1684 break;
1685 case PR_GET_UNALIGN:
1686 error = GET_UNALIGN_CTL(current, arg2);
1687 break;
1688 case PR_SET_FPEMU:
1689 error = SET_FPEMU_CTL(current, arg2);
1690 break;
1691 case PR_GET_FPEMU:
1692 error = GET_FPEMU_CTL(current, arg2);
1693 break;
1694 case PR_SET_FPEXC:
1695 error = SET_FPEXC_CTL(current, arg2);
1696 break;
1697 case PR_GET_FPEXC:
1698 error = GET_FPEXC_CTL(current, arg2);
1699 break;
1700 case PR_GET_TIMING:
1701 error = PR_TIMING_STATISTICAL;
1702 break;
1703 case PR_SET_TIMING:
1704 if (arg2 != PR_TIMING_STATISTICAL)
1705 error = -EINVAL;
1706 break;
1707
1708 case PR_SET_NAME: {
1709 struct task_struct *me = current;
1710 unsigned char ncomm[sizeof(me->comm)];
1711
1712 ncomm[sizeof(me->comm)-1] = 0;
1713 if (strncpy_from_user(ncomm, (char __user *)arg2,
1714 sizeof(me->comm)-1) < 0)
1715 return -EFAULT;
1716 set_task_comm(me, ncomm);
1717 return 0;
1718 }
1719 case PR_GET_NAME: {
1720 struct task_struct *me = current;
1721 unsigned char tcomm[sizeof(me->comm)];
1722
1723 get_task_comm(tcomm, me);
1724 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1725 return -EFAULT;
1726 return 0;
1727 }
1728 case PR_GET_ENDIAN:
1729 error = GET_ENDIAN(current, arg2);
1730 break;
1731 case PR_SET_ENDIAN:
1732 error = SET_ENDIAN(current, arg2);
1733 break;
1734
1735 case PR_GET_SECCOMP:
1736 error = prctl_get_seccomp();
1737 break;
1738 case PR_SET_SECCOMP:
1739 error = prctl_set_seccomp(arg2);
1740 break;
1741 case PR_GET_TSC:
1742 error = GET_TSC_CTL(arg2);
1743 break;
1744 case PR_SET_TSC:
1745 error = SET_TSC_CTL(arg2);
1746 break;
1747 default:
1748 error = -EINVAL;
1749 break;
1750 }
1751 return error;
1752}
1753
1754asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1755 struct getcpu_cache __user *unused)
1756{
1757 int err = 0;
1758 int cpu = raw_smp_processor_id();
1759 if (cpup)
1760 err |= put_user(cpu, cpup);
1761 if (nodep)
1762 err |= put_user(cpu_to_node(cpu), nodep);
1763 return err ? -EFAULT : 0;
1764}
1765
1766char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1767
1768static void argv_cleanup(char **argv, char **envp)
1769{
1770 argv_free(argv);
1771}
1772
1773/**
1774 * orderly_poweroff - Trigger an orderly system poweroff
1775 * @force: force poweroff if command execution fails
1776 *
1777 * This may be called from any context to trigger a system shutdown.
1778 * If the orderly shutdown fails, it will force an immediate shutdown.
1779 */
1780int orderly_poweroff(bool force)
1781{
1782 int argc;
1783 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1784 static char *envp[] = {
1785 "HOME=/",
1786 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1787 NULL
1788 };
1789 int ret = -ENOMEM;
1790 struct subprocess_info *info;
1791
1792 if (argv == NULL) {
1793 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1794 __func__, poweroff_cmd);
1795 goto out;
1796 }
1797
1798 info = call_usermodehelper_setup(argv[0], argv, envp);
1799 if (info == NULL) {
1800 argv_free(argv);
1801 goto out;
1802 }
1803
1804 call_usermodehelper_setcleanup(info, argv_cleanup);
1805
1806 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1807
1808 out:
1809 if (ret && force) {
1810 printk(KERN_WARNING "Failed to start orderly shutdown: "
1811 "forcing the issue\n");
1812
1813 /* I guess this should try to kick off some daemon to
1814 sync and poweroff asap. Or not even bother syncing
1815 if we're doing an emergency shutdown? */
1816 emergency_sync();
1817 kernel_power_off();
1818 }
1819
1820 return ret;
1821}
1822EXPORT_SYMBOL_GPL(orderly_poweroff);