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[deliverable/linux.git] / kernel / sys.c
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 asmlinkage long sys_times(struct tms __user * tbuf)
857 {
858 /*
859 * In the SMP world we might just be unlucky and have one of
860 * the times increment as we use it. Since the value is an
861 * atomically safe type this is just fine. Conceptually its
862 * as if the syscall took an instant longer to occur.
863 */
864 if (tbuf) {
865 struct tms tmp;
866 struct task_struct *tsk = current;
867 struct task_struct *t;
868 cputime_t utime, stime, cutime, cstime;
869
870 spin_lock_irq(&tsk->sighand->siglock);
871 utime = tsk->signal->utime;
872 stime = tsk->signal->stime;
873 t = tsk;
874 do {
875 utime = cputime_add(utime, t->utime);
876 stime = cputime_add(stime, t->stime);
877 t = next_thread(t);
878 } while (t != tsk);
879
880 cutime = tsk->signal->cutime;
881 cstime = tsk->signal->cstime;
882 spin_unlock_irq(&tsk->sighand->siglock);
883
884 tmp.tms_utime = cputime_to_clock_t(utime);
885 tmp.tms_stime = cputime_to_clock_t(stime);
886 tmp.tms_cutime = cputime_to_clock_t(cutime);
887 tmp.tms_cstime = cputime_to_clock_t(cstime);
888 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
889 return -EFAULT;
890 }
891 return (long) jiffies_64_to_clock_t(get_jiffies_64());
892 }
893
894 /*
895 * This needs some heavy checking ...
896 * I just haven't the stomach for it. I also don't fully
897 * understand sessions/pgrp etc. Let somebody who does explain it.
898 *
899 * OK, I think I have the protection semantics right.... this is really
900 * only important on a multi-user system anyway, to make sure one user
901 * can't send a signal to a process owned by another. -TYT, 12/12/91
902 *
903 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
904 * LBT 04.03.94
905 */
906 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
907 {
908 struct task_struct *p;
909 struct task_struct *group_leader = current->group_leader;
910 struct pid *pgrp;
911 int err;
912
913 if (!pid)
914 pid = task_pid_vnr(group_leader);
915 if (!pgid)
916 pgid = pid;
917 if (pgid < 0)
918 return -EINVAL;
919
920 /* From this point forward we keep holding onto the tasklist lock
921 * so that our parent does not change from under us. -DaveM
922 */
923 write_lock_irq(&tasklist_lock);
924
925 err = -ESRCH;
926 p = find_task_by_vpid(pid);
927 if (!p)
928 goto out;
929
930 err = -EINVAL;
931 if (!thread_group_leader(p))
932 goto out;
933
934 if (same_thread_group(p->real_parent, group_leader)) {
935 err = -EPERM;
936 if (task_session(p) != task_session(group_leader))
937 goto out;
938 err = -EACCES;
939 if (p->did_exec)
940 goto out;
941 } else {
942 err = -ESRCH;
943 if (p != group_leader)
944 goto out;
945 }
946
947 err = -EPERM;
948 if (p->signal->leader)
949 goto out;
950
951 pgrp = task_pid(p);
952 if (pgid != pid) {
953 struct task_struct *g;
954
955 pgrp = find_vpid(pgid);
956 g = pid_task(pgrp, PIDTYPE_PGID);
957 if (!g || task_session(g) != task_session(group_leader))
958 goto out;
959 }
960
961 err = security_task_setpgid(p, pgid);
962 if (err)
963 goto out;
964
965 if (task_pgrp(p) != pgrp) {
966 change_pid(p, PIDTYPE_PGID, pgrp);
967 set_task_pgrp(p, pid_nr(pgrp));
968 }
969
970 err = 0;
971 out:
972 /* All paths lead to here, thus we are safe. -DaveM */
973 write_unlock_irq(&tasklist_lock);
974 return err;
975 }
976
977 asmlinkage long sys_getpgid(pid_t pid)
978 {
979 struct task_struct *p;
980 struct pid *grp;
981 int retval;
982
983 rcu_read_lock();
984 if (!pid)
985 grp = task_pgrp(current);
986 else {
987 retval = -ESRCH;
988 p = find_task_by_vpid(pid);
989 if (!p)
990 goto out;
991 grp = task_pgrp(p);
992 if (!grp)
993 goto out;
994
995 retval = security_task_getpgid(p);
996 if (retval)
997 goto out;
998 }
999 retval = pid_vnr(grp);
1000 out:
1001 rcu_read_unlock();
1002 return retval;
1003 }
1004
1005 #ifdef __ARCH_WANT_SYS_GETPGRP
1006
1007 asmlinkage long sys_getpgrp(void)
1008 {
1009 return sys_getpgid(0);
1010 }
1011
1012 #endif
1013
1014 asmlinkage long sys_getsid(pid_t pid)
1015 {
1016 struct task_struct *p;
1017 struct pid *sid;
1018 int retval;
1019
1020 rcu_read_lock();
1021 if (!pid)
1022 sid = task_session(current);
1023 else {
1024 retval = -ESRCH;
1025 p = find_task_by_vpid(pid);
1026 if (!p)
1027 goto out;
1028 sid = task_session(p);
1029 if (!sid)
1030 goto out;
1031
1032 retval = security_task_getsid(p);
1033 if (retval)
1034 goto out;
1035 }
1036 retval = pid_vnr(sid);
1037 out:
1038 rcu_read_unlock();
1039 return retval;
1040 }
1041
1042 asmlinkage long sys_setsid(void)
1043 {
1044 struct task_struct *group_leader = current->group_leader;
1045 struct pid *sid = task_pid(group_leader);
1046 pid_t session = pid_vnr(sid);
1047 int err = -EPERM;
1048
1049 write_lock_irq(&tasklist_lock);
1050 /* Fail if I am already a session leader */
1051 if (group_leader->signal->leader)
1052 goto out;
1053
1054 /* Fail if a process group id already exists that equals the
1055 * proposed session id.
1056 */
1057 if (pid_task(sid, PIDTYPE_PGID))
1058 goto out;
1059
1060 group_leader->signal->leader = 1;
1061 __set_special_pids(sid);
1062
1063 proc_clear_tty(group_leader);
1064
1065 err = session;
1066 out:
1067 write_unlock_irq(&tasklist_lock);
1068 return err;
1069 }
1070
1071 /*
1072 * Supplementary group IDs
1073 */
1074
1075 /* init to 2 - one for init_task, one to ensure it is never freed */
1076 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1077
1078 struct group_info *groups_alloc(int gidsetsize)
1079 {
1080 struct group_info *group_info;
1081 int nblocks;
1082 int i;
1083
1084 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1085 /* Make sure we always allocate at least one indirect block pointer */
1086 nblocks = nblocks ? : 1;
1087 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1088 if (!group_info)
1089 return NULL;
1090 group_info->ngroups = gidsetsize;
1091 group_info->nblocks = nblocks;
1092 atomic_set(&group_info->usage, 1);
1093
1094 if (gidsetsize <= NGROUPS_SMALL)
1095 group_info->blocks[0] = group_info->small_block;
1096 else {
1097 for (i = 0; i < nblocks; i++) {
1098 gid_t *b;
1099 b = (void *)__get_free_page(GFP_USER);
1100 if (!b)
1101 goto out_undo_partial_alloc;
1102 group_info->blocks[i] = b;
1103 }
1104 }
1105 return group_info;
1106
1107 out_undo_partial_alloc:
1108 while (--i >= 0) {
1109 free_page((unsigned long)group_info->blocks[i]);
1110 }
1111 kfree(group_info);
1112 return NULL;
1113 }
1114
1115 EXPORT_SYMBOL(groups_alloc);
1116
1117 void groups_free(struct group_info *group_info)
1118 {
1119 if (group_info->blocks[0] != group_info->small_block) {
1120 int i;
1121 for (i = 0; i < group_info->nblocks; i++)
1122 free_page((unsigned long)group_info->blocks[i]);
1123 }
1124 kfree(group_info);
1125 }
1126
1127 EXPORT_SYMBOL(groups_free);
1128
1129 /* export the group_info to a user-space array */
1130 static int groups_to_user(gid_t __user *grouplist,
1131 struct group_info *group_info)
1132 {
1133 int i;
1134 unsigned int count = group_info->ngroups;
1135
1136 for (i = 0; i < group_info->nblocks; i++) {
1137 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1138 unsigned int len = cp_count * sizeof(*grouplist);
1139
1140 if (copy_to_user(grouplist, group_info->blocks[i], len))
1141 return -EFAULT;
1142
1143 grouplist += NGROUPS_PER_BLOCK;
1144 count -= cp_count;
1145 }
1146 return 0;
1147 }
1148
1149 /* fill a group_info from a user-space array - it must be allocated already */
1150 static int groups_from_user(struct group_info *group_info,
1151 gid_t __user *grouplist)
1152 {
1153 int i;
1154 unsigned int count = group_info->ngroups;
1155
1156 for (i = 0; i < group_info->nblocks; i++) {
1157 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1158 unsigned int len = cp_count * sizeof(*grouplist);
1159
1160 if (copy_from_user(group_info->blocks[i], grouplist, len))
1161 return -EFAULT;
1162
1163 grouplist += NGROUPS_PER_BLOCK;
1164 count -= cp_count;
1165 }
1166 return 0;
1167 }
1168
1169 /* a simple Shell sort */
1170 static void groups_sort(struct group_info *group_info)
1171 {
1172 int base, max, stride;
1173 int gidsetsize = group_info->ngroups;
1174
1175 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1176 ; /* nothing */
1177 stride /= 3;
1178
1179 while (stride) {
1180 max = gidsetsize - stride;
1181 for (base = 0; base < max; base++) {
1182 int left = base;
1183 int right = left + stride;
1184 gid_t tmp = GROUP_AT(group_info, right);
1185
1186 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1187 GROUP_AT(group_info, right) =
1188 GROUP_AT(group_info, left);
1189 right = left;
1190 left -= stride;
1191 }
1192 GROUP_AT(group_info, right) = tmp;
1193 }
1194 stride /= 3;
1195 }
1196 }
1197
1198 /* a simple bsearch */
1199 int groups_search(struct group_info *group_info, gid_t grp)
1200 {
1201 unsigned int left, right;
1202
1203 if (!group_info)
1204 return 0;
1205
1206 left = 0;
1207 right = group_info->ngroups;
1208 while (left < right) {
1209 unsigned int mid = (left+right)/2;
1210 int cmp = grp - GROUP_AT(group_info, mid);
1211 if (cmp > 0)
1212 left = mid + 1;
1213 else if (cmp < 0)
1214 right = mid;
1215 else
1216 return 1;
1217 }
1218 return 0;
1219 }
1220
1221 /* validate and set current->group_info */
1222 int set_current_groups(struct group_info *group_info)
1223 {
1224 int retval;
1225 struct group_info *old_info;
1226
1227 retval = security_task_setgroups(group_info);
1228 if (retval)
1229 return retval;
1230
1231 groups_sort(group_info);
1232 get_group_info(group_info);
1233
1234 task_lock(current);
1235 old_info = current->group_info;
1236 current->group_info = group_info;
1237 task_unlock(current);
1238
1239 put_group_info(old_info);
1240
1241 return 0;
1242 }
1243
1244 EXPORT_SYMBOL(set_current_groups);
1245
1246 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1247 {
1248 int i = 0;
1249
1250 /*
1251 * SMP: Nobody else can change our grouplist. Thus we are
1252 * safe.
1253 */
1254
1255 if (gidsetsize < 0)
1256 return -EINVAL;
1257
1258 /* no need to grab task_lock here; it cannot change */
1259 i = current->group_info->ngroups;
1260 if (gidsetsize) {
1261 if (i > gidsetsize) {
1262 i = -EINVAL;
1263 goto out;
1264 }
1265 if (groups_to_user(grouplist, current->group_info)) {
1266 i = -EFAULT;
1267 goto out;
1268 }
1269 }
1270 out:
1271 return i;
1272 }
1273
1274 /*
1275 * SMP: Our groups are copy-on-write. We can set them safely
1276 * without another task interfering.
1277 */
1278
1279 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1280 {
1281 struct group_info *group_info;
1282 int retval;
1283
1284 if (!capable(CAP_SETGID))
1285 return -EPERM;
1286 if ((unsigned)gidsetsize > NGROUPS_MAX)
1287 return -EINVAL;
1288
1289 group_info = groups_alloc(gidsetsize);
1290 if (!group_info)
1291 return -ENOMEM;
1292 retval = groups_from_user(group_info, grouplist);
1293 if (retval) {
1294 put_group_info(group_info);
1295 return retval;
1296 }
1297
1298 retval = set_current_groups(group_info);
1299 put_group_info(group_info);
1300
1301 return retval;
1302 }
1303
1304 /*
1305 * Check whether we're fsgid/egid or in the supplemental group..
1306 */
1307 int in_group_p(gid_t grp)
1308 {
1309 int retval = 1;
1310 if (grp != current->fsgid)
1311 retval = groups_search(current->group_info, grp);
1312 return retval;
1313 }
1314
1315 EXPORT_SYMBOL(in_group_p);
1316
1317 int in_egroup_p(gid_t grp)
1318 {
1319 int retval = 1;
1320 if (grp != current->egid)
1321 retval = groups_search(current->group_info, grp);
1322 return retval;
1323 }
1324
1325 EXPORT_SYMBOL(in_egroup_p);
1326
1327 DECLARE_RWSEM(uts_sem);
1328
1329 asmlinkage long sys_newuname(struct new_utsname __user * name)
1330 {
1331 int errno = 0;
1332
1333 down_read(&uts_sem);
1334 if (copy_to_user(name, utsname(), sizeof *name))
1335 errno = -EFAULT;
1336 up_read(&uts_sem);
1337 return errno;
1338 }
1339
1340 asmlinkage long sys_sethostname(char __user *name, int len)
1341 {
1342 int errno;
1343 char tmp[__NEW_UTS_LEN];
1344
1345 if (!capable(CAP_SYS_ADMIN))
1346 return -EPERM;
1347 if (len < 0 || len > __NEW_UTS_LEN)
1348 return -EINVAL;
1349 down_write(&uts_sem);
1350 errno = -EFAULT;
1351 if (!copy_from_user(tmp, name, len)) {
1352 memcpy(utsname()->nodename, tmp, len);
1353 memset(utsname()->nodename + len, 0,
1354 sizeof(utsname()->nodename) - len);
1355 errno = 0;
1356 }
1357 up_write(&uts_sem);
1358 return errno;
1359 }
1360
1361 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1362
1363 asmlinkage long sys_gethostname(char __user *name, int len)
1364 {
1365 int i, errno;
1366
1367 if (len < 0)
1368 return -EINVAL;
1369 down_read(&uts_sem);
1370 i = 1 + strlen(utsname()->nodename);
1371 if (i > len)
1372 i = len;
1373 errno = 0;
1374 if (copy_to_user(name, utsname()->nodename, i))
1375 errno = -EFAULT;
1376 up_read(&uts_sem);
1377 return errno;
1378 }
1379
1380 #endif
1381
1382 /*
1383 * Only setdomainname; getdomainname can be implemented by calling
1384 * uname()
1385 */
1386 asmlinkage long sys_setdomainname(char __user *name, int len)
1387 {
1388 int errno;
1389 char tmp[__NEW_UTS_LEN];
1390
1391 if (!capable(CAP_SYS_ADMIN))
1392 return -EPERM;
1393 if (len < 0 || len > __NEW_UTS_LEN)
1394 return -EINVAL;
1395
1396 down_write(&uts_sem);
1397 errno = -EFAULT;
1398 if (!copy_from_user(tmp, name, len)) {
1399 memcpy(utsname()->domainname, tmp, len);
1400 memset(utsname()->domainname + len, 0,
1401 sizeof(utsname()->domainname) - len);
1402 errno = 0;
1403 }
1404 up_write(&uts_sem);
1405 return errno;
1406 }
1407
1408 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1409 {
1410 if (resource >= RLIM_NLIMITS)
1411 return -EINVAL;
1412 else {
1413 struct rlimit value;
1414 task_lock(current->group_leader);
1415 value = current->signal->rlim[resource];
1416 task_unlock(current->group_leader);
1417 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1418 }
1419 }
1420
1421 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1422
1423 /*
1424 * Back compatibility for getrlimit. Needed for some apps.
1425 */
1426
1427 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1428 {
1429 struct rlimit x;
1430 if (resource >= RLIM_NLIMITS)
1431 return -EINVAL;
1432
1433 task_lock(current->group_leader);
1434 x = current->signal->rlim[resource];
1435 task_unlock(current->group_leader);
1436 if (x.rlim_cur > 0x7FFFFFFF)
1437 x.rlim_cur = 0x7FFFFFFF;
1438 if (x.rlim_max > 0x7FFFFFFF)
1439 x.rlim_max = 0x7FFFFFFF;
1440 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1441 }
1442
1443 #endif
1444
1445 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1446 {
1447 struct rlimit new_rlim, *old_rlim;
1448 unsigned long it_prof_secs;
1449 int retval;
1450
1451 if (resource >= RLIM_NLIMITS)
1452 return -EINVAL;
1453 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1454 return -EFAULT;
1455 old_rlim = current->signal->rlim + resource;
1456 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1457 !capable(CAP_SYS_RESOURCE))
1458 return -EPERM;
1459
1460 if (resource == RLIMIT_NOFILE) {
1461 if (new_rlim.rlim_max == RLIM_INFINITY)
1462 new_rlim.rlim_max = sysctl_nr_open;
1463 if (new_rlim.rlim_cur == RLIM_INFINITY)
1464 new_rlim.rlim_cur = sysctl_nr_open;
1465 if (new_rlim.rlim_max > sysctl_nr_open)
1466 return -EPERM;
1467 }
1468
1469 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1470 return -EINVAL;
1471
1472 retval = security_task_setrlimit(resource, &new_rlim);
1473 if (retval)
1474 return retval;
1475
1476 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1477 /*
1478 * The caller is asking for an immediate RLIMIT_CPU
1479 * expiry. But we use the zero value to mean "it was
1480 * never set". So let's cheat and make it one second
1481 * instead
1482 */
1483 new_rlim.rlim_cur = 1;
1484 }
1485
1486 task_lock(current->group_leader);
1487 *old_rlim = new_rlim;
1488 task_unlock(current->group_leader);
1489
1490 if (resource != RLIMIT_CPU)
1491 goto out;
1492
1493 /*
1494 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1495 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1496 * very long-standing error, and fixing it now risks breakage of
1497 * applications, so we live with it
1498 */
1499 if (new_rlim.rlim_cur == RLIM_INFINITY)
1500 goto out;
1501
1502 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1503 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1504 unsigned long rlim_cur = new_rlim.rlim_cur;
1505 cputime_t cputime;
1506
1507 cputime = secs_to_cputime(rlim_cur);
1508 read_lock(&tasklist_lock);
1509 spin_lock_irq(&current->sighand->siglock);
1510 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1511 spin_unlock_irq(&current->sighand->siglock);
1512 read_unlock(&tasklist_lock);
1513 }
1514 out:
1515 return 0;
1516 }
1517
1518 /*
1519 * It would make sense to put struct rusage in the task_struct,
1520 * except that would make the task_struct be *really big*. After
1521 * task_struct gets moved into malloc'ed memory, it would
1522 * make sense to do this. It will make moving the rest of the information
1523 * a lot simpler! (Which we're not doing right now because we're not
1524 * measuring them yet).
1525 *
1526 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1527 * races with threads incrementing their own counters. But since word
1528 * reads are atomic, we either get new values or old values and we don't
1529 * care which for the sums. We always take the siglock to protect reading
1530 * the c* fields from p->signal from races with exit.c updating those
1531 * fields when reaping, so a sample either gets all the additions of a
1532 * given child after it's reaped, or none so this sample is before reaping.
1533 *
1534 * Locking:
1535 * We need to take the siglock for CHILDEREN, SELF and BOTH
1536 * for the cases current multithreaded, non-current single threaded
1537 * non-current multithreaded. Thread traversal is now safe with
1538 * the siglock held.
1539 * Strictly speaking, we donot need to take the siglock if we are current and
1540 * single threaded, as no one else can take our signal_struct away, no one
1541 * else can reap the children to update signal->c* counters, and no one else
1542 * can race with the signal-> fields. If we do not take any lock, the
1543 * signal-> fields could be read out of order while another thread was just
1544 * exiting. So we should place a read memory barrier when we avoid the lock.
1545 * On the writer side, write memory barrier is implied in __exit_signal
1546 * as __exit_signal releases the siglock spinlock after updating the signal->
1547 * fields. But we don't do this yet to keep things simple.
1548 *
1549 */
1550
1551 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
1552 cputime_t *utimep, cputime_t *stimep)
1553 {
1554 *utimep = cputime_add(*utimep, t->utime);
1555 *stimep = cputime_add(*stimep, t->stime);
1556 r->ru_nvcsw += t->nvcsw;
1557 r->ru_nivcsw += t->nivcsw;
1558 r->ru_minflt += t->min_flt;
1559 r->ru_majflt += t->maj_flt;
1560 r->ru_inblock += task_io_get_inblock(t);
1561 r->ru_oublock += task_io_get_oublock(t);
1562 }
1563
1564 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1565 {
1566 struct task_struct *t;
1567 unsigned long flags;
1568 cputime_t utime, stime;
1569
1570 memset((char *) r, 0, sizeof *r);
1571 utime = stime = cputime_zero;
1572
1573 if (who == RUSAGE_THREAD) {
1574 accumulate_thread_rusage(p, r, &utime, &stime);
1575 goto out;
1576 }
1577
1578 if (!lock_task_sighand(p, &flags))
1579 return;
1580
1581 switch (who) {
1582 case RUSAGE_BOTH:
1583 case RUSAGE_CHILDREN:
1584 utime = p->signal->cutime;
1585 stime = p->signal->cstime;
1586 r->ru_nvcsw = p->signal->cnvcsw;
1587 r->ru_nivcsw = p->signal->cnivcsw;
1588 r->ru_minflt = p->signal->cmin_flt;
1589 r->ru_majflt = p->signal->cmaj_flt;
1590 r->ru_inblock = p->signal->cinblock;
1591 r->ru_oublock = p->signal->coublock;
1592
1593 if (who == RUSAGE_CHILDREN)
1594 break;
1595
1596 case RUSAGE_SELF:
1597 utime = cputime_add(utime, p->signal->utime);
1598 stime = cputime_add(stime, p->signal->stime);
1599 r->ru_nvcsw += p->signal->nvcsw;
1600 r->ru_nivcsw += p->signal->nivcsw;
1601 r->ru_minflt += p->signal->min_flt;
1602 r->ru_majflt += p->signal->maj_flt;
1603 r->ru_inblock += p->signal->inblock;
1604 r->ru_oublock += p->signal->oublock;
1605 t = p;
1606 do {
1607 accumulate_thread_rusage(t, r, &utime, &stime);
1608 t = next_thread(t);
1609 } while (t != p);
1610 break;
1611
1612 default:
1613 BUG();
1614 }
1615 unlock_task_sighand(p, &flags);
1616
1617 out:
1618 cputime_to_timeval(utime, &r->ru_utime);
1619 cputime_to_timeval(stime, &r->ru_stime);
1620 }
1621
1622 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1623 {
1624 struct rusage r;
1625 k_getrusage(p, who, &r);
1626 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1627 }
1628
1629 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1630 {
1631 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1632 who != RUSAGE_THREAD)
1633 return -EINVAL;
1634 return getrusage(current, who, ru);
1635 }
1636
1637 asmlinkage long sys_umask(int mask)
1638 {
1639 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1640 return mask;
1641 }
1642
1643 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1644 unsigned long arg4, unsigned long arg5)
1645 {
1646 long error = 0;
1647
1648 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1649 return error;
1650
1651 switch (option) {
1652 case PR_SET_PDEATHSIG:
1653 if (!valid_signal(arg2)) {
1654 error = -EINVAL;
1655 break;
1656 }
1657 current->pdeath_signal = arg2;
1658 break;
1659 case PR_GET_PDEATHSIG:
1660 error = put_user(current->pdeath_signal, (int __user *)arg2);
1661 break;
1662 case PR_GET_DUMPABLE:
1663 error = get_dumpable(current->mm);
1664 break;
1665 case PR_SET_DUMPABLE:
1666 if (arg2 < 0 || arg2 > 1) {
1667 error = -EINVAL;
1668 break;
1669 }
1670 set_dumpable(current->mm, arg2);
1671 break;
1672
1673 case PR_SET_UNALIGN:
1674 error = SET_UNALIGN_CTL(current, arg2);
1675 break;
1676 case PR_GET_UNALIGN:
1677 error = GET_UNALIGN_CTL(current, arg2);
1678 break;
1679 case PR_SET_FPEMU:
1680 error = SET_FPEMU_CTL(current, arg2);
1681 break;
1682 case PR_GET_FPEMU:
1683 error = GET_FPEMU_CTL(current, arg2);
1684 break;
1685 case PR_SET_FPEXC:
1686 error = SET_FPEXC_CTL(current, arg2);
1687 break;
1688 case PR_GET_FPEXC:
1689 error = GET_FPEXC_CTL(current, arg2);
1690 break;
1691 case PR_GET_TIMING:
1692 error = PR_TIMING_STATISTICAL;
1693 break;
1694 case PR_SET_TIMING:
1695 if (arg2 != PR_TIMING_STATISTICAL)
1696 error = -EINVAL;
1697 break;
1698
1699 case PR_SET_NAME: {
1700 struct task_struct *me = current;
1701 unsigned char ncomm[sizeof(me->comm)];
1702
1703 ncomm[sizeof(me->comm)-1] = 0;
1704 if (strncpy_from_user(ncomm, (char __user *)arg2,
1705 sizeof(me->comm)-1) < 0)
1706 return -EFAULT;
1707 set_task_comm(me, ncomm);
1708 return 0;
1709 }
1710 case PR_GET_NAME: {
1711 struct task_struct *me = current;
1712 unsigned char tcomm[sizeof(me->comm)];
1713
1714 get_task_comm(tcomm, me);
1715 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1716 return -EFAULT;
1717 return 0;
1718 }
1719 case PR_GET_ENDIAN:
1720 error = GET_ENDIAN(current, arg2);
1721 break;
1722 case PR_SET_ENDIAN:
1723 error = SET_ENDIAN(current, arg2);
1724 break;
1725
1726 case PR_GET_SECCOMP:
1727 error = prctl_get_seccomp();
1728 break;
1729 case PR_SET_SECCOMP:
1730 error = prctl_set_seccomp(arg2);
1731 break;
1732 case PR_GET_TSC:
1733 error = GET_TSC_CTL(arg2);
1734 break;
1735 case PR_SET_TSC:
1736 error = SET_TSC_CTL(arg2);
1737 break;
1738 default:
1739 error = -EINVAL;
1740 break;
1741 }
1742 return error;
1743 }
1744
1745 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1746 struct getcpu_cache __user *unused)
1747 {
1748 int err = 0;
1749 int cpu = raw_smp_processor_id();
1750 if (cpup)
1751 err |= put_user(cpu, cpup);
1752 if (nodep)
1753 err |= put_user(cpu_to_node(cpu), nodep);
1754 return err ? -EFAULT : 0;
1755 }
1756
1757 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1758
1759 static void argv_cleanup(char **argv, char **envp)
1760 {
1761 argv_free(argv);
1762 }
1763
1764 /**
1765 * orderly_poweroff - Trigger an orderly system poweroff
1766 * @force: force poweroff if command execution fails
1767 *
1768 * This may be called from any context to trigger a system shutdown.
1769 * If the orderly shutdown fails, it will force an immediate shutdown.
1770 */
1771 int orderly_poweroff(bool force)
1772 {
1773 int argc;
1774 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1775 static char *envp[] = {
1776 "HOME=/",
1777 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1778 NULL
1779 };
1780 int ret = -ENOMEM;
1781 struct subprocess_info *info;
1782
1783 if (argv == NULL) {
1784 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1785 __func__, poweroff_cmd);
1786 goto out;
1787 }
1788
1789 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1790 if (info == NULL) {
1791 argv_free(argv);
1792 goto out;
1793 }
1794
1795 call_usermodehelper_setcleanup(info, argv_cleanup);
1796
1797 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1798
1799 out:
1800 if (ret && force) {
1801 printk(KERN_WARNING "Failed to start orderly shutdown: "
1802 "forcing the issue\n");
1803
1804 /* I guess this should try to kick off some daemon to
1805 sync and poweroff asap. Or not even bother syncing
1806 if we're doing an emergency shutdown? */
1807 emergency_sync();
1808 kernel_power_off();
1809 }
1810
1811 return ret;
1812 }
1813 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linux kernel - Deliverables
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