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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
71 /*
72 * this is where the system-wide overflow UID and GID are defined, for
73 * architectures that now have 32-bit UID/GID but didn't in the past
74 */
75
76 int overflowuid = DEFAULT_OVERFLOWUID;
77 int overflowgid = DEFAULT_OVERFLOWGID;
78
79 #ifdef CONFIG_UID16
80 EXPORT_SYMBOL(overflowuid);
81 EXPORT_SYMBOL(overflowgid);
82 #endif
83
84 /*
85 * the same as above, but for filesystems which can only store a 16-bit
86 * UID and GID. as such, this is needed on all architectures
87 */
88
89 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
90 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
91
92 EXPORT_SYMBOL(fs_overflowuid);
93 EXPORT_SYMBOL(fs_overflowgid);
94
95 /*
96 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
97 */
98
99 int C_A_D = 1;
100 struct pid *cad_pid;
101 EXPORT_SYMBOL(cad_pid);
102
103 /*
104 * If set, this is used for preparing the system to power off.
105 */
106
107 void (*pm_power_off_prepare)(void);
108
109 static int set_one_prio(struct task_struct *p, int niceval, int error)
110 {
111 int no_nice;
112
113 if (p->uid != current->euid &&
114 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
115 error = -EPERM;
116 goto out;
117 }
118 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
119 error = -EACCES;
120 goto out;
121 }
122 no_nice = security_task_setnice(p, niceval);
123 if (no_nice) {
124 error = no_nice;
125 goto out;
126 }
127 if (error == -ESRCH)
128 error = 0;
129 set_user_nice(p, niceval);
130 out:
131 return error;
132 }
133
134 asmlinkage long sys_setpriority(int which, int who, int niceval)
135 {
136 struct task_struct *g, *p;
137 struct user_struct *user;
138 int error = -EINVAL;
139 struct pid *pgrp;
140
141 if (which > PRIO_USER || which < PRIO_PROCESS)
142 goto out;
143
144 /* normalize: avoid signed division (rounding problems) */
145 error = -ESRCH;
146 if (niceval < -20)
147 niceval = -20;
148 if (niceval > 19)
149 niceval = 19;
150
151 read_lock(&tasklist_lock);
152 switch (which) {
153 case PRIO_PROCESS:
154 if (who)
155 p = find_task_by_pid_ns(who,
156 current->nsproxy->pid_ns);
157 else
158 p = current;
159 if (p)
160 error = set_one_prio(p, niceval, error);
161 break;
162 case PRIO_PGRP:
163 if (who)
164 pgrp = find_vpid(who);
165 else
166 pgrp = task_pgrp(current);
167 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
168 error = set_one_prio(p, niceval, error);
169 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
170 break;
171 case PRIO_USER:
172 user = current->user;
173 if (!who)
174 who = current->uid;
175 else
176 if ((who != current->uid) && !(user = find_user(who)))
177 goto out_unlock; /* No processes for this user */
178
179 do_each_thread(g, p)
180 if (p->uid == who)
181 error = set_one_prio(p, niceval, error);
182 while_each_thread(g, p);
183 if (who != current->uid)
184 free_uid(user); /* For find_user() */
185 break;
186 }
187 out_unlock:
188 read_unlock(&tasklist_lock);
189 out:
190 return error;
191 }
192
193 /*
194 * Ugh. To avoid negative return values, "getpriority()" will
195 * not return the normal nice-value, but a negated value that
196 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
197 * to stay compatible.
198 */
199 asmlinkage long sys_getpriority(int which, int who)
200 {
201 struct task_struct *g, *p;
202 struct user_struct *user;
203 long niceval, retval = -ESRCH;
204 struct pid *pgrp;
205
206 if (which > PRIO_USER || which < PRIO_PROCESS)
207 return -EINVAL;
208
209 read_lock(&tasklist_lock);
210 switch (which) {
211 case PRIO_PROCESS:
212 if (who)
213 p = find_task_by_pid_ns(who,
214 current->nsproxy->pid_ns);
215 else
216 p = current;
217 if (p) {
218 niceval = 20 - task_nice(p);
219 if (niceval > retval)
220 retval = niceval;
221 }
222 break;
223 case PRIO_PGRP:
224 if (who)
225 pgrp = find_vpid(who);
226 else
227 pgrp = task_pgrp(current);
228 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
229 niceval = 20 - task_nice(p);
230 if (niceval > retval)
231 retval = niceval;
232 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
233 break;
234 case PRIO_USER:
235 user = current->user;
236 if (!who)
237 who = current->uid;
238 else
239 if ((who != current->uid) && !(user = find_user(who)))
240 goto out_unlock; /* No processes for this user */
241
242 do_each_thread(g, p)
243 if (p->uid == who) {
244 niceval = 20 - task_nice(p);
245 if (niceval > retval)
246 retval = niceval;
247 }
248 while_each_thread(g, p);
249 if (who != current->uid)
250 free_uid(user); /* for find_user() */
251 break;
252 }
253 out_unlock:
254 read_unlock(&tasklist_lock);
255
256 return retval;
257 }
258
259 /**
260 * emergency_restart - reboot the system
261 *
262 * Without shutting down any hardware or taking any locks
263 * reboot the system. This is called when we know we are in
264 * trouble so this is our best effort to reboot. This is
265 * safe to call in interrupt context.
266 */
267 void emergency_restart(void)
268 {
269 machine_emergency_restart();
270 }
271 EXPORT_SYMBOL_GPL(emergency_restart);
272
273 static void kernel_restart_prepare(char *cmd)
274 {
275 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
276 system_state = SYSTEM_RESTART;
277 device_shutdown();
278 sysdev_shutdown();
279 }
280
281 /**
282 * kernel_restart - reboot the system
283 * @cmd: pointer to buffer containing command to execute for restart
284 * or %NULL
285 *
286 * Shutdown everything and perform a clean reboot.
287 * This is not safe to call in interrupt context.
288 */
289 void kernel_restart(char *cmd)
290 {
291 kernel_restart_prepare(cmd);
292 if (!cmd)
293 printk(KERN_EMERG "Restarting system.\n");
294 else
295 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
296 machine_restart(cmd);
297 }
298 EXPORT_SYMBOL_GPL(kernel_restart);
299
300 /**
301 * kernel_kexec - reboot the system
302 *
303 * Move into place and start executing a preloaded standalone
304 * executable. If nothing was preloaded return an error.
305 */
306 static void kernel_kexec(void)
307 {
308 #ifdef CONFIG_KEXEC
309 struct kimage *image;
310 image = xchg(&kexec_image, NULL);
311 if (!image)
312 return;
313 kernel_restart_prepare(NULL);
314 printk(KERN_EMERG "Starting new kernel\n");
315 machine_shutdown();
316 machine_kexec(image);
317 #endif
318 }
319
320 void kernel_shutdown_prepare(enum system_states state)
321 {
322 blocking_notifier_call_chain(&reboot_notifier_list,
323 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
324 system_state = state;
325 device_shutdown();
326 }
327 /**
328 * kernel_halt - halt the system
329 *
330 * Shutdown everything and perform a clean system halt.
331 */
332 void kernel_halt(void)
333 {
334 kernel_shutdown_prepare(SYSTEM_HALT);
335 sysdev_shutdown();
336 printk(KERN_EMERG "System halted.\n");
337 machine_halt();
338 }
339
340 EXPORT_SYMBOL_GPL(kernel_halt);
341
342 /**
343 * kernel_power_off - power_off the system
344 *
345 * Shutdown everything and perform a clean system power_off.
346 */
347 void kernel_power_off(void)
348 {
349 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
350 if (pm_power_off_prepare)
351 pm_power_off_prepare();
352 disable_nonboot_cpus();
353 sysdev_shutdown();
354 printk(KERN_EMERG "Power down.\n");
355 machine_power_off();
356 }
357 EXPORT_SYMBOL_GPL(kernel_power_off);
358 /*
359 * Reboot system call: for obvious reasons only root may call it,
360 * and even root needs to set up some magic numbers in the registers
361 * so that some mistake won't make this reboot the whole machine.
362 * You can also set the meaning of the ctrl-alt-del-key here.
363 *
364 * reboot doesn't sync: do that yourself before calling this.
365 */
366 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
367 {
368 char buffer[256];
369
370 /* We only trust the superuser with rebooting the system. */
371 if (!capable(CAP_SYS_BOOT))
372 return -EPERM;
373
374 /* For safety, we require "magic" arguments. */
375 if (magic1 != LINUX_REBOOT_MAGIC1 ||
376 (magic2 != LINUX_REBOOT_MAGIC2 &&
377 magic2 != LINUX_REBOOT_MAGIC2A &&
378 magic2 != LINUX_REBOOT_MAGIC2B &&
379 magic2 != LINUX_REBOOT_MAGIC2C))
380 return -EINVAL;
381
382 /* Instead of trying to make the power_off code look like
383 * halt when pm_power_off is not set do it the easy way.
384 */
385 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
386 cmd = LINUX_REBOOT_CMD_HALT;
387
388 lock_kernel();
389 switch (cmd) {
390 case LINUX_REBOOT_CMD_RESTART:
391 kernel_restart(NULL);
392 break;
393
394 case LINUX_REBOOT_CMD_CAD_ON:
395 C_A_D = 1;
396 break;
397
398 case LINUX_REBOOT_CMD_CAD_OFF:
399 C_A_D = 0;
400 break;
401
402 case LINUX_REBOOT_CMD_HALT:
403 kernel_halt();
404 unlock_kernel();
405 do_exit(0);
406 break;
407
408 case LINUX_REBOOT_CMD_POWER_OFF:
409 kernel_power_off();
410 unlock_kernel();
411 do_exit(0);
412 break;
413
414 case LINUX_REBOOT_CMD_RESTART2:
415 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
416 unlock_kernel();
417 return -EFAULT;
418 }
419 buffer[sizeof(buffer) - 1] = '\0';
420
421 kernel_restart(buffer);
422 break;
423
424 case LINUX_REBOOT_CMD_KEXEC:
425 kernel_kexec();
426 unlock_kernel();
427 return -EINVAL;
428
429 #ifdef CONFIG_HIBERNATION
430 case LINUX_REBOOT_CMD_SW_SUSPEND:
431 {
432 int ret = hibernate();
433 unlock_kernel();
434 return ret;
435 }
436 #endif
437
438 default:
439 unlock_kernel();
440 return -EINVAL;
441 }
442 unlock_kernel();
443 return 0;
444 }
445
446 static void deferred_cad(struct work_struct *dummy)
447 {
448 kernel_restart(NULL);
449 }
450
451 /*
452 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
453 * As it's called within an interrupt, it may NOT sync: the only choice
454 * is whether to reboot at once, or just ignore the ctrl-alt-del.
455 */
456 void ctrl_alt_del(void)
457 {
458 static DECLARE_WORK(cad_work, deferred_cad);
459
460 if (C_A_D)
461 schedule_work(&cad_work);
462 else
463 kill_cad_pid(SIGINT, 1);
464 }
465
466 /*
467 * Unprivileged users may change the real gid to the effective gid
468 * or vice versa. (BSD-style)
469 *
470 * If you set the real gid at all, or set the effective gid to a value not
471 * equal to the real gid, then the saved gid is set to the new effective gid.
472 *
473 * This makes it possible for a setgid program to completely drop its
474 * privileges, which is often a useful assertion to make when you are doing
475 * a security audit over a program.
476 *
477 * The general idea is that a program which uses just setregid() will be
478 * 100% compatible with BSD. A program which uses just setgid() will be
479 * 100% compatible with POSIX with saved IDs.
480 *
481 * SMP: There are not races, the GIDs are checked only by filesystem
482 * operations (as far as semantic preservation is concerned).
483 */
484 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
485 {
486 int old_rgid = current->gid;
487 int old_egid = current->egid;
488 int new_rgid = old_rgid;
489 int new_egid = old_egid;
490 int retval;
491
492 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
493 if (retval)
494 return retval;
495
496 if (rgid != (gid_t) -1) {
497 if ((old_rgid == rgid) ||
498 (current->egid==rgid) ||
499 capable(CAP_SETGID))
500 new_rgid = rgid;
501 else
502 return -EPERM;
503 }
504 if (egid != (gid_t) -1) {
505 if ((old_rgid == egid) ||
506 (current->egid == egid) ||
507 (current->sgid == egid) ||
508 capable(CAP_SETGID))
509 new_egid = egid;
510 else
511 return -EPERM;
512 }
513 if (new_egid != old_egid) {
514 set_dumpable(current->mm, suid_dumpable);
515 smp_wmb();
516 }
517 if (rgid != (gid_t) -1 ||
518 (egid != (gid_t) -1 && egid != old_rgid))
519 current->sgid = new_egid;
520 current->fsgid = new_egid;
521 current->egid = new_egid;
522 current->gid = new_rgid;
523 key_fsgid_changed(current);
524 proc_id_connector(current, PROC_EVENT_GID);
525 return 0;
526 }
527
528 /*
529 * setgid() is implemented like SysV w/ SAVED_IDS
530 *
531 * SMP: Same implicit races as above.
532 */
533 asmlinkage long sys_setgid(gid_t gid)
534 {
535 int old_egid = current->egid;
536 int retval;
537
538 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
539 if (retval)
540 return retval;
541
542 if (capable(CAP_SETGID)) {
543 if (old_egid != gid) {
544 set_dumpable(current->mm, suid_dumpable);
545 smp_wmb();
546 }
547 current->gid = current->egid = current->sgid = current->fsgid = gid;
548 } else if ((gid == current->gid) || (gid == current->sgid)) {
549 if (old_egid != gid) {
550 set_dumpable(current->mm, suid_dumpable);
551 smp_wmb();
552 }
553 current->egid = current->fsgid = gid;
554 }
555 else
556 return -EPERM;
557
558 key_fsgid_changed(current);
559 proc_id_connector(current, PROC_EVENT_GID);
560 return 0;
561 }
562
563 static int set_user(uid_t new_ruid, int dumpclear)
564 {
565 struct user_struct *new_user;
566
567 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
568 if (!new_user)
569 return -EAGAIN;
570
571 if (atomic_read(&new_user->processes) >=
572 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
573 new_user != current->nsproxy->user_ns->root_user) {
574 free_uid(new_user);
575 return -EAGAIN;
576 }
577
578 switch_uid(new_user);
579
580 if (dumpclear) {
581 set_dumpable(current->mm, suid_dumpable);
582 smp_wmb();
583 }
584 current->uid = new_ruid;
585 return 0;
586 }
587
588 /*
589 * Unprivileged users may change the real uid to the effective uid
590 * or vice versa. (BSD-style)
591 *
592 * If you set the real uid at all, or set the effective uid to a value not
593 * equal to the real uid, then the saved uid is set to the new effective uid.
594 *
595 * This makes it possible for a setuid program to completely drop its
596 * privileges, which is often a useful assertion to make when you are doing
597 * a security audit over a program.
598 *
599 * The general idea is that a program which uses just setreuid() will be
600 * 100% compatible with BSD. A program which uses just setuid() will be
601 * 100% compatible with POSIX with saved IDs.
602 */
603 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
604 {
605 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
606 int retval;
607
608 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
609 if (retval)
610 return retval;
611
612 new_ruid = old_ruid = current->uid;
613 new_euid = old_euid = current->euid;
614 old_suid = current->suid;
615
616 if (ruid != (uid_t) -1) {
617 new_ruid = ruid;
618 if ((old_ruid != ruid) &&
619 (current->euid != ruid) &&
620 !capable(CAP_SETUID))
621 return -EPERM;
622 }
623
624 if (euid != (uid_t) -1) {
625 new_euid = euid;
626 if ((old_ruid != euid) &&
627 (current->euid != euid) &&
628 (current->suid != euid) &&
629 !capable(CAP_SETUID))
630 return -EPERM;
631 }
632
633 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
634 return -EAGAIN;
635
636 if (new_euid != old_euid) {
637 set_dumpable(current->mm, suid_dumpable);
638 smp_wmb();
639 }
640 current->fsuid = current->euid = new_euid;
641 if (ruid != (uid_t) -1 ||
642 (euid != (uid_t) -1 && euid != old_ruid))
643 current->suid = current->euid;
644 current->fsuid = current->euid;
645
646 key_fsuid_changed(current);
647 proc_id_connector(current, PROC_EVENT_UID);
648
649 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
650 }
651
652
653
654 /*
655 * setuid() is implemented like SysV with SAVED_IDS
656 *
657 * Note that SAVED_ID's is deficient in that a setuid root program
658 * like sendmail, for example, cannot set its uid to be a normal
659 * user and then switch back, because if you're root, setuid() sets
660 * the saved uid too. If you don't like this, blame the bright people
661 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
662 * will allow a root program to temporarily drop privileges and be able to
663 * regain them by swapping the real and effective uid.
664 */
665 asmlinkage long sys_setuid(uid_t uid)
666 {
667 int old_euid = current->euid;
668 int old_ruid, old_suid, new_suid;
669 int retval;
670
671 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
672 if (retval)
673 return retval;
674
675 old_ruid = current->uid;
676 old_suid = current->suid;
677 new_suid = old_suid;
678
679 if (capable(CAP_SETUID)) {
680 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
681 return -EAGAIN;
682 new_suid = uid;
683 } else if ((uid != current->uid) && (uid != new_suid))
684 return -EPERM;
685
686 if (old_euid != uid) {
687 set_dumpable(current->mm, suid_dumpable);
688 smp_wmb();
689 }
690 current->fsuid = current->euid = uid;
691 current->suid = new_suid;
692
693 key_fsuid_changed(current);
694 proc_id_connector(current, PROC_EVENT_UID);
695
696 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
697 }
698
699
700 /*
701 * This function implements a generic ability to update ruid, euid,
702 * and suid. This allows you to implement the 4.4 compatible seteuid().
703 */
704 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
705 {
706 int old_ruid = current->uid;
707 int old_euid = current->euid;
708 int old_suid = current->suid;
709 int retval;
710
711 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
712 if (retval)
713 return retval;
714
715 if (!capable(CAP_SETUID)) {
716 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
717 (ruid != current->euid) && (ruid != current->suid))
718 return -EPERM;
719 if ((euid != (uid_t) -1) && (euid != current->uid) &&
720 (euid != current->euid) && (euid != current->suid))
721 return -EPERM;
722 if ((suid != (uid_t) -1) && (suid != current->uid) &&
723 (suid != current->euid) && (suid != current->suid))
724 return -EPERM;
725 }
726 if (ruid != (uid_t) -1) {
727 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
728 return -EAGAIN;
729 }
730 if (euid != (uid_t) -1) {
731 if (euid != current->euid) {
732 set_dumpable(current->mm, suid_dumpable);
733 smp_wmb();
734 }
735 current->euid = euid;
736 }
737 current->fsuid = current->euid;
738 if (suid != (uid_t) -1)
739 current->suid = suid;
740
741 key_fsuid_changed(current);
742 proc_id_connector(current, PROC_EVENT_UID);
743
744 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
745 }
746
747 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
748 {
749 int retval;
750
751 if (!(retval = put_user(current->uid, ruid)) &&
752 !(retval = put_user(current->euid, euid)))
753 retval = put_user(current->suid, suid);
754
755 return retval;
756 }
757
758 /*
759 * Same as above, but for rgid, egid, sgid.
760 */
761 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
762 {
763 int retval;
764
765 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
766 if (retval)
767 return retval;
768
769 if (!capable(CAP_SETGID)) {
770 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
771 (rgid != current->egid) && (rgid != current->sgid))
772 return -EPERM;
773 if ((egid != (gid_t) -1) && (egid != current->gid) &&
774 (egid != current->egid) && (egid != current->sgid))
775 return -EPERM;
776 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
777 (sgid != current->egid) && (sgid != current->sgid))
778 return -EPERM;
779 }
780 if (egid != (gid_t) -1) {
781 if (egid != current->egid) {
782 set_dumpable(current->mm, suid_dumpable);
783 smp_wmb();
784 }
785 current->egid = egid;
786 }
787 current->fsgid = current->egid;
788 if (rgid != (gid_t) -1)
789 current->gid = rgid;
790 if (sgid != (gid_t) -1)
791 current->sgid = sgid;
792
793 key_fsgid_changed(current);
794 proc_id_connector(current, PROC_EVENT_GID);
795 return 0;
796 }
797
798 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
799 {
800 int retval;
801
802 if (!(retval = put_user(current->gid, rgid)) &&
803 !(retval = put_user(current->egid, egid)))
804 retval = put_user(current->sgid, sgid);
805
806 return retval;
807 }
808
809
810 /*
811 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
812 * is used for "access()" and for the NFS daemon (letting nfsd stay at
813 * whatever uid it wants to). It normally shadows "euid", except when
814 * explicitly set by setfsuid() or for access..
815 */
816 asmlinkage long sys_setfsuid(uid_t uid)
817 {
818 int old_fsuid;
819
820 old_fsuid = current->fsuid;
821 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
822 return old_fsuid;
823
824 if (uid == current->uid || uid == current->euid ||
825 uid == current->suid || uid == current->fsuid ||
826 capable(CAP_SETUID)) {
827 if (uid != old_fsuid) {
828 set_dumpable(current->mm, suid_dumpable);
829 smp_wmb();
830 }
831 current->fsuid = uid;
832 }
833
834 key_fsuid_changed(current);
835 proc_id_connector(current, PROC_EVENT_UID);
836
837 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
838
839 return old_fsuid;
840 }
841
842 /*
843 * Samma på svenska..
844 */
845 asmlinkage long sys_setfsgid(gid_t gid)
846 {
847 int old_fsgid;
848
849 old_fsgid = current->fsgid;
850 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
851 return old_fsgid;
852
853 if (gid == current->gid || gid == current->egid ||
854 gid == current->sgid || gid == current->fsgid ||
855 capable(CAP_SETGID)) {
856 if (gid != old_fsgid) {
857 set_dumpable(current->mm, suid_dumpable);
858 smp_wmb();
859 }
860 current->fsgid = gid;
861 key_fsgid_changed(current);
862 proc_id_connector(current, PROC_EVENT_GID);
863 }
864 return old_fsgid;
865 }
866
867 asmlinkage long sys_times(struct tms __user * tbuf)
868 {
869 /*
870 * In the SMP world we might just be unlucky and have one of
871 * the times increment as we use it. Since the value is an
872 * atomically safe type this is just fine. Conceptually its
873 * as if the syscall took an instant longer to occur.
874 */
875 if (tbuf) {
876 struct tms tmp;
877 struct task_struct *tsk = current;
878 struct task_struct *t;
879 cputime_t utime, stime, cutime, cstime;
880
881 spin_lock_irq(&tsk->sighand->siglock);
882 utime = tsk->signal->utime;
883 stime = tsk->signal->stime;
884 t = tsk;
885 do {
886 utime = cputime_add(utime, t->utime);
887 stime = cputime_add(stime, t->stime);
888 t = next_thread(t);
889 } while (t != tsk);
890
891 cutime = tsk->signal->cutime;
892 cstime = tsk->signal->cstime;
893 spin_unlock_irq(&tsk->sighand->siglock);
894
895 tmp.tms_utime = cputime_to_clock_t(utime);
896 tmp.tms_stime = cputime_to_clock_t(stime);
897 tmp.tms_cutime = cputime_to_clock_t(cutime);
898 tmp.tms_cstime = cputime_to_clock_t(cstime);
899 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
900 return -EFAULT;
901 }
902 return (long) jiffies_64_to_clock_t(get_jiffies_64());
903 }
904
905 /*
906 * This needs some heavy checking ...
907 * I just haven't the stomach for it. I also don't fully
908 * understand sessions/pgrp etc. Let somebody who does explain it.
909 *
910 * OK, I think I have the protection semantics right.... this is really
911 * only important on a multi-user system anyway, to make sure one user
912 * can't send a signal to a process owned by another. -TYT, 12/12/91
913 *
914 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
915 * LBT 04.03.94
916 */
917 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
918 {
919 struct task_struct *p;
920 struct task_struct *group_leader = current->group_leader;
921 int err = -EINVAL;
922 struct pid_namespace *ns;
923
924 if (!pid)
925 pid = task_pid_vnr(group_leader);
926 if (!pgid)
927 pgid = pid;
928 if (pgid < 0)
929 return -EINVAL;
930
931 /* From this point forward we keep holding onto the tasklist lock
932 * so that our parent does not change from under us. -DaveM
933 */
934 ns = current->nsproxy->pid_ns;
935
936 write_lock_irq(&tasklist_lock);
937
938 err = -ESRCH;
939 p = find_task_by_pid_ns(pid, ns);
940 if (!p)
941 goto out;
942
943 err = -EINVAL;
944 if (!thread_group_leader(p))
945 goto out;
946
947 if (p->real_parent->tgid == group_leader->tgid) {
948 err = -EPERM;
949 if (task_session(p) != task_session(group_leader))
950 goto out;
951 err = -EACCES;
952 if (p->did_exec)
953 goto out;
954 } else {
955 err = -ESRCH;
956 if (p != group_leader)
957 goto out;
958 }
959
960 err = -EPERM;
961 if (p->signal->leader)
962 goto out;
963
964 if (pgid != pid) {
965 struct task_struct *g;
966
967 g = find_task_by_pid_type_ns(PIDTYPE_PGID, pgid, ns);
968 if (!g || task_session(g) != task_session(group_leader))
969 goto out;
970 }
971
972 err = security_task_setpgid(p, pgid);
973 if (err)
974 goto out;
975
976 if (task_pgrp_nr_ns(p, ns) != pgid) {
977 struct pid *pid;
978
979 detach_pid(p, PIDTYPE_PGID);
980 pid = find_vpid(pgid);
981 attach_pid(p, PIDTYPE_PGID, pid);
982 p->signal->pgrp = pid_nr(pid);
983 }
984
985 err = 0;
986 out:
987 /* All paths lead to here, thus we are safe. -DaveM */
988 write_unlock_irq(&tasklist_lock);
989 return err;
990 }
991
992 asmlinkage long sys_getpgid(pid_t pid)
993 {
994 if (!pid)
995 return task_pgrp_vnr(current);
996 else {
997 int retval;
998 struct task_struct *p;
999 struct pid_namespace *ns;
1000
1001 ns = current->nsproxy->pid_ns;
1002
1003 read_lock(&tasklist_lock);
1004 p = find_task_by_pid_ns(pid, ns);
1005 retval = -ESRCH;
1006 if (p) {
1007 retval = security_task_getpgid(p);
1008 if (!retval)
1009 retval = task_pgrp_nr_ns(p, ns);
1010 }
1011 read_unlock(&tasklist_lock);
1012 return retval;
1013 }
1014 }
1015
1016 #ifdef __ARCH_WANT_SYS_GETPGRP
1017
1018 asmlinkage long sys_getpgrp(void)
1019 {
1020 /* SMP - assuming writes are word atomic this is fine */
1021 return task_pgrp_vnr(current);
1022 }
1023
1024 #endif
1025
1026 asmlinkage long sys_getsid(pid_t pid)
1027 {
1028 if (!pid)
1029 return task_session_vnr(current);
1030 else {
1031 int retval;
1032 struct task_struct *p;
1033 struct pid_namespace *ns;
1034
1035 ns = current->nsproxy->pid_ns;
1036
1037 read_lock(&tasklist_lock);
1038 p = find_task_by_pid_ns(pid, ns);
1039 retval = -ESRCH;
1040 if (p) {
1041 retval = security_task_getsid(p);
1042 if (!retval)
1043 retval = task_session_nr_ns(p, ns);
1044 }
1045 read_unlock(&tasklist_lock);
1046 return retval;
1047 }
1048 }
1049
1050 asmlinkage long sys_setsid(void)
1051 {
1052 struct task_struct *group_leader = current->group_leader;
1053 pid_t session;
1054 int err = -EPERM;
1055
1056 write_lock_irq(&tasklist_lock);
1057
1058 /* Fail if I am already a session leader */
1059 if (group_leader->signal->leader)
1060 goto out;
1061
1062 session = group_leader->pid;
1063 /* Fail if a process group id already exists that equals the
1064 * proposed session id.
1065 *
1066 * Don't check if session id == 1 because kernel threads use this
1067 * session id and so the check will always fail and make it so
1068 * init cannot successfully call setsid.
1069 */
1070 if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))
1071 goto out;
1072
1073 group_leader->signal->leader = 1;
1074 __set_special_pids(session, session);
1075
1076 spin_lock(&group_leader->sighand->siglock);
1077 group_leader->signal->tty = NULL;
1078 spin_unlock(&group_leader->sighand->siglock);
1079
1080 err = task_pgrp_vnr(group_leader);
1081 out:
1082 write_unlock_irq(&tasklist_lock);
1083 return err;
1084 }
1085
1086 /*
1087 * Supplementary group IDs
1088 */
1089
1090 /* init to 2 - one for init_task, one to ensure it is never freed */
1091 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1092
1093 struct group_info *groups_alloc(int gidsetsize)
1094 {
1095 struct group_info *group_info;
1096 int nblocks;
1097 int i;
1098
1099 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1100 /* Make sure we always allocate at least one indirect block pointer */
1101 nblocks = nblocks ? : 1;
1102 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1103 if (!group_info)
1104 return NULL;
1105 group_info->ngroups = gidsetsize;
1106 group_info->nblocks = nblocks;
1107 atomic_set(&group_info->usage, 1);
1108
1109 if (gidsetsize <= NGROUPS_SMALL)
1110 group_info->blocks[0] = group_info->small_block;
1111 else {
1112 for (i = 0; i < nblocks; i++) {
1113 gid_t *b;
1114 b = (void *)__get_free_page(GFP_USER);
1115 if (!b)
1116 goto out_undo_partial_alloc;
1117 group_info->blocks[i] = b;
1118 }
1119 }
1120 return group_info;
1121
1122 out_undo_partial_alloc:
1123 while (--i >= 0) {
1124 free_page((unsigned long)group_info->blocks[i]);
1125 }
1126 kfree(group_info);
1127 return NULL;
1128 }
1129
1130 EXPORT_SYMBOL(groups_alloc);
1131
1132 void groups_free(struct group_info *group_info)
1133 {
1134 if (group_info->blocks[0] != group_info->small_block) {
1135 int i;
1136 for (i = 0; i < group_info->nblocks; i++)
1137 free_page((unsigned long)group_info->blocks[i]);
1138 }
1139 kfree(group_info);
1140 }
1141
1142 EXPORT_SYMBOL(groups_free);
1143
1144 /* export the group_info to a user-space array */
1145 static int groups_to_user(gid_t __user *grouplist,
1146 struct group_info *group_info)
1147 {
1148 int i;
1149 int count = group_info->ngroups;
1150
1151 for (i = 0; i < group_info->nblocks; i++) {
1152 int cp_count = min(NGROUPS_PER_BLOCK, count);
1153 int off = i * NGROUPS_PER_BLOCK;
1154 int len = cp_count * sizeof(*grouplist);
1155
1156 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1157 return -EFAULT;
1158
1159 count -= cp_count;
1160 }
1161 return 0;
1162 }
1163
1164 /* fill a group_info from a user-space array - it must be allocated already */
1165 static int groups_from_user(struct group_info *group_info,
1166 gid_t __user *grouplist)
1167 {
1168 int i;
1169 int count = group_info->ngroups;
1170
1171 for (i = 0; i < group_info->nblocks; i++) {
1172 int cp_count = min(NGROUPS_PER_BLOCK, count);
1173 int off = i * NGROUPS_PER_BLOCK;
1174 int len = cp_count * sizeof(*grouplist);
1175
1176 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1177 return -EFAULT;
1178
1179 count -= cp_count;
1180 }
1181 return 0;
1182 }
1183
1184 /* a simple Shell sort */
1185 static void groups_sort(struct group_info *group_info)
1186 {
1187 int base, max, stride;
1188 int gidsetsize = group_info->ngroups;
1189
1190 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1191 ; /* nothing */
1192 stride /= 3;
1193
1194 while (stride) {
1195 max = gidsetsize - stride;
1196 for (base = 0; base < max; base++) {
1197 int left = base;
1198 int right = left + stride;
1199 gid_t tmp = GROUP_AT(group_info, right);
1200
1201 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1202 GROUP_AT(group_info, right) =
1203 GROUP_AT(group_info, left);
1204 right = left;
1205 left -= stride;
1206 }
1207 GROUP_AT(group_info, right) = tmp;
1208 }
1209 stride /= 3;
1210 }
1211 }
1212
1213 /* a simple bsearch */
1214 int groups_search(struct group_info *group_info, gid_t grp)
1215 {
1216 unsigned int left, right;
1217
1218 if (!group_info)
1219 return 0;
1220
1221 left = 0;
1222 right = group_info->ngroups;
1223 while (left < right) {
1224 unsigned int mid = (left+right)/2;
1225 int cmp = grp - GROUP_AT(group_info, mid);
1226 if (cmp > 0)
1227 left = mid + 1;
1228 else if (cmp < 0)
1229 right = mid;
1230 else
1231 return 1;
1232 }
1233 return 0;
1234 }
1235
1236 /* validate and set current->group_info */
1237 int set_current_groups(struct group_info *group_info)
1238 {
1239 int retval;
1240 struct group_info *old_info;
1241
1242 retval = security_task_setgroups(group_info);
1243 if (retval)
1244 return retval;
1245
1246 groups_sort(group_info);
1247 get_group_info(group_info);
1248
1249 task_lock(current);
1250 old_info = current->group_info;
1251 current->group_info = group_info;
1252 task_unlock(current);
1253
1254 put_group_info(old_info);
1255
1256 return 0;
1257 }
1258
1259 EXPORT_SYMBOL(set_current_groups);
1260
1261 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1262 {
1263 int i = 0;
1264
1265 /*
1266 * SMP: Nobody else can change our grouplist. Thus we are
1267 * safe.
1268 */
1269
1270 if (gidsetsize < 0)
1271 return -EINVAL;
1272
1273 /* no need to grab task_lock here; it cannot change */
1274 i = current->group_info->ngroups;
1275 if (gidsetsize) {
1276 if (i > gidsetsize) {
1277 i = -EINVAL;
1278 goto out;
1279 }
1280 if (groups_to_user(grouplist, current->group_info)) {
1281 i = -EFAULT;
1282 goto out;
1283 }
1284 }
1285 out:
1286 return i;
1287 }
1288
1289 /*
1290 * SMP: Our groups are copy-on-write. We can set them safely
1291 * without another task interfering.
1292 */
1293
1294 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1295 {
1296 struct group_info *group_info;
1297 int retval;
1298
1299 if (!capable(CAP_SETGID))
1300 return -EPERM;
1301 if ((unsigned)gidsetsize > NGROUPS_MAX)
1302 return -EINVAL;
1303
1304 group_info = groups_alloc(gidsetsize);
1305 if (!group_info)
1306 return -ENOMEM;
1307 retval = groups_from_user(group_info, grouplist);
1308 if (retval) {
1309 put_group_info(group_info);
1310 return retval;
1311 }
1312
1313 retval = set_current_groups(group_info);
1314 put_group_info(group_info);
1315
1316 return retval;
1317 }
1318
1319 /*
1320 * Check whether we're fsgid/egid or in the supplemental group..
1321 */
1322 int in_group_p(gid_t grp)
1323 {
1324 int retval = 1;
1325 if (grp != current->fsgid)
1326 retval = groups_search(current->group_info, grp);
1327 return retval;
1328 }
1329
1330 EXPORT_SYMBOL(in_group_p);
1331
1332 int in_egroup_p(gid_t grp)
1333 {
1334 int retval = 1;
1335 if (grp != current->egid)
1336 retval = groups_search(current->group_info, grp);
1337 return retval;
1338 }
1339
1340 EXPORT_SYMBOL(in_egroup_p);
1341
1342 DECLARE_RWSEM(uts_sem);
1343
1344 EXPORT_SYMBOL(uts_sem);
1345
1346 asmlinkage long sys_newuname(struct new_utsname __user * name)
1347 {
1348 int errno = 0;
1349
1350 down_read(&uts_sem);
1351 if (copy_to_user(name, utsname(), sizeof *name))
1352 errno = -EFAULT;
1353 up_read(&uts_sem);
1354 return errno;
1355 }
1356
1357 asmlinkage long sys_sethostname(char __user *name, int len)
1358 {
1359 int errno;
1360 char tmp[__NEW_UTS_LEN];
1361
1362 if (!capable(CAP_SYS_ADMIN))
1363 return -EPERM;
1364 if (len < 0 || len > __NEW_UTS_LEN)
1365 return -EINVAL;
1366 down_write(&uts_sem);
1367 errno = -EFAULT;
1368 if (!copy_from_user(tmp, name, len)) {
1369 memcpy(utsname()->nodename, tmp, len);
1370 utsname()->nodename[len] = 0;
1371 errno = 0;
1372 }
1373 up_write(&uts_sem);
1374 return errno;
1375 }
1376
1377 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1378
1379 asmlinkage long sys_gethostname(char __user *name, int len)
1380 {
1381 int i, errno;
1382
1383 if (len < 0)
1384 return -EINVAL;
1385 down_read(&uts_sem);
1386 i = 1 + strlen(utsname()->nodename);
1387 if (i > len)
1388 i = len;
1389 errno = 0;
1390 if (copy_to_user(name, utsname()->nodename, i))
1391 errno = -EFAULT;
1392 up_read(&uts_sem);
1393 return errno;
1394 }
1395
1396 #endif
1397
1398 /*
1399 * Only setdomainname; getdomainname can be implemented by calling
1400 * uname()
1401 */
1402 asmlinkage long sys_setdomainname(char __user *name, int len)
1403 {
1404 int errno;
1405 char tmp[__NEW_UTS_LEN];
1406
1407 if (!capable(CAP_SYS_ADMIN))
1408 return -EPERM;
1409 if (len < 0 || len > __NEW_UTS_LEN)
1410 return -EINVAL;
1411
1412 down_write(&uts_sem);
1413 errno = -EFAULT;
1414 if (!copy_from_user(tmp, name, len)) {
1415 memcpy(utsname()->domainname, tmp, len);
1416 utsname()->domainname[len] = 0;
1417 errno = 0;
1418 }
1419 up_write(&uts_sem);
1420 return errno;
1421 }
1422
1423 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1424 {
1425 if (resource >= RLIM_NLIMITS)
1426 return -EINVAL;
1427 else {
1428 struct rlimit value;
1429 task_lock(current->group_leader);
1430 value = current->signal->rlim[resource];
1431 task_unlock(current->group_leader);
1432 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1433 }
1434 }
1435
1436 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1437
1438 /*
1439 * Back compatibility for getrlimit. Needed for some apps.
1440 */
1441
1442 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1443 {
1444 struct rlimit x;
1445 if (resource >= RLIM_NLIMITS)
1446 return -EINVAL;
1447
1448 task_lock(current->group_leader);
1449 x = current->signal->rlim[resource];
1450 task_unlock(current->group_leader);
1451 if (x.rlim_cur > 0x7FFFFFFF)
1452 x.rlim_cur = 0x7FFFFFFF;
1453 if (x.rlim_max > 0x7FFFFFFF)
1454 x.rlim_max = 0x7FFFFFFF;
1455 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1456 }
1457
1458 #endif
1459
1460 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1461 {
1462 struct rlimit new_rlim, *old_rlim;
1463 unsigned long it_prof_secs;
1464 int retval;
1465
1466 if (resource >= RLIM_NLIMITS)
1467 return -EINVAL;
1468 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1469 return -EFAULT;
1470 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1471 return -EINVAL;
1472 old_rlim = current->signal->rlim + resource;
1473 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1474 !capable(CAP_SYS_RESOURCE))
1475 return -EPERM;
1476 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1477 return -EPERM;
1478
1479 retval = security_task_setrlimit(resource, &new_rlim);
1480 if (retval)
1481 return retval;
1482
1483 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1484 /*
1485 * The caller is asking for an immediate RLIMIT_CPU
1486 * expiry. But we use the zero value to mean "it was
1487 * never set". So let's cheat and make it one second
1488 * instead
1489 */
1490 new_rlim.rlim_cur = 1;
1491 }
1492
1493 task_lock(current->group_leader);
1494 *old_rlim = new_rlim;
1495 task_unlock(current->group_leader);
1496
1497 if (resource != RLIMIT_CPU)
1498 goto out;
1499
1500 /*
1501 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1502 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1503 * very long-standing error, and fixing it now risks breakage of
1504 * applications, so we live with it
1505 */
1506 if (new_rlim.rlim_cur == RLIM_INFINITY)
1507 goto out;
1508
1509 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1510 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1511 unsigned long rlim_cur = new_rlim.rlim_cur;
1512 cputime_t cputime;
1513
1514 cputime = secs_to_cputime(rlim_cur);
1515 read_lock(&tasklist_lock);
1516 spin_lock_irq(&current->sighand->siglock);
1517 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1518 spin_unlock_irq(&current->sighand->siglock);
1519 read_unlock(&tasklist_lock);
1520 }
1521 out:
1522 return 0;
1523 }
1524
1525 /*
1526 * It would make sense to put struct rusage in the task_struct,
1527 * except that would make the task_struct be *really big*. After
1528 * task_struct gets moved into malloc'ed memory, it would
1529 * make sense to do this. It will make moving the rest of the information
1530 * a lot simpler! (Which we're not doing right now because we're not
1531 * measuring them yet).
1532 *
1533 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1534 * races with threads incrementing their own counters. But since word
1535 * reads are atomic, we either get new values or old values and we don't
1536 * care which for the sums. We always take the siglock to protect reading
1537 * the c* fields from p->signal from races with exit.c updating those
1538 * fields when reaping, so a sample either gets all the additions of a
1539 * given child after it's reaped, or none so this sample is before reaping.
1540 *
1541 * Locking:
1542 * We need to take the siglock for CHILDEREN, SELF and BOTH
1543 * for the cases current multithreaded, non-current single threaded
1544 * non-current multithreaded. Thread traversal is now safe with
1545 * the siglock held.
1546 * Strictly speaking, we donot need to take the siglock if we are current and
1547 * single threaded, as no one else can take our signal_struct away, no one
1548 * else can reap the children to update signal->c* counters, and no one else
1549 * can race with the signal-> fields. If we do not take any lock, the
1550 * signal-> fields could be read out of order while another thread was just
1551 * exiting. So we should place a read memory barrier when we avoid the lock.
1552 * On the writer side, write memory barrier is implied in __exit_signal
1553 * as __exit_signal releases the siglock spinlock after updating the signal->
1554 * fields. But we don't do this yet to keep things simple.
1555 *
1556 */
1557
1558 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1559 {
1560 struct task_struct *t;
1561 unsigned long flags;
1562 cputime_t utime, stime;
1563
1564 memset((char *) r, 0, sizeof *r);
1565 utime = stime = cputime_zero;
1566
1567 rcu_read_lock();
1568 if (!lock_task_sighand(p, &flags)) {
1569 rcu_read_unlock();
1570 return;
1571 }
1572
1573 switch (who) {
1574 case RUSAGE_BOTH:
1575 case RUSAGE_CHILDREN:
1576 utime = p->signal->cutime;
1577 stime = p->signal->cstime;
1578 r->ru_nvcsw = p->signal->cnvcsw;
1579 r->ru_nivcsw = p->signal->cnivcsw;
1580 r->ru_minflt = p->signal->cmin_flt;
1581 r->ru_majflt = p->signal->cmaj_flt;
1582 r->ru_inblock = p->signal->cinblock;
1583 r->ru_oublock = p->signal->coublock;
1584
1585 if (who == RUSAGE_CHILDREN)
1586 break;
1587
1588 case RUSAGE_SELF:
1589 utime = cputime_add(utime, p->signal->utime);
1590 stime = cputime_add(stime, p->signal->stime);
1591 r->ru_nvcsw += p->signal->nvcsw;
1592 r->ru_nivcsw += p->signal->nivcsw;
1593 r->ru_minflt += p->signal->min_flt;
1594 r->ru_majflt += p->signal->maj_flt;
1595 r->ru_inblock += p->signal->inblock;
1596 r->ru_oublock += p->signal->oublock;
1597 t = p;
1598 do {
1599 utime = cputime_add(utime, t->utime);
1600 stime = cputime_add(stime, t->stime);
1601 r->ru_nvcsw += t->nvcsw;
1602 r->ru_nivcsw += t->nivcsw;
1603 r->ru_minflt += t->min_flt;
1604 r->ru_majflt += t->maj_flt;
1605 r->ru_inblock += task_io_get_inblock(t);
1606 r->ru_oublock += task_io_get_oublock(t);
1607 t = next_thread(t);
1608 } while (t != p);
1609 break;
1610
1611 default:
1612 BUG();
1613 }
1614
1615 unlock_task_sighand(p, &flags);
1616 rcu_read_unlock();
1617
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 return -EINVAL;
1633 return getrusage(current, who, ru);
1634 }
1635
1636 asmlinkage long sys_umask(int mask)
1637 {
1638 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1639 return mask;
1640 }
1641
1642 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1643 unsigned long arg4, unsigned long arg5)
1644 {
1645 long error;
1646
1647 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1648 if (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 = 0;
1697 else
1698 error = -EINVAL;
1699 break;
1700
1701 case PR_GET_KEEPCAPS:
1702 if (current->keep_capabilities)
1703 error = 1;
1704 break;
1705 case PR_SET_KEEPCAPS:
1706 if (arg2 != 0 && arg2 != 1) {
1707 error = -EINVAL;
1708 break;
1709 }
1710 current->keep_capabilities = arg2;
1711 break;
1712 case PR_SET_NAME: {
1713 struct task_struct *me = current;
1714 unsigned char ncomm[sizeof(me->comm)];
1715
1716 ncomm[sizeof(me->comm)-1] = 0;
1717 if (strncpy_from_user(ncomm, (char __user *)arg2,
1718 sizeof(me->comm)-1) < 0)
1719 return -EFAULT;
1720 set_task_comm(me, ncomm);
1721 return 0;
1722 }
1723 case PR_GET_NAME: {
1724 struct task_struct *me = current;
1725 unsigned char tcomm[sizeof(me->comm)];
1726
1727 get_task_comm(tcomm, me);
1728 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1729 return -EFAULT;
1730 return 0;
1731 }
1732 case PR_GET_ENDIAN:
1733 error = GET_ENDIAN(current, arg2);
1734 break;
1735 case PR_SET_ENDIAN:
1736 error = SET_ENDIAN(current, arg2);
1737 break;
1738
1739 case PR_GET_SECCOMP:
1740 error = prctl_get_seccomp();
1741 break;
1742 case PR_SET_SECCOMP:
1743 error = prctl_set_seccomp(arg2);
1744 break;
1745
1746 default:
1747 error = -EINVAL;
1748 break;
1749 }
1750 return error;
1751 }
1752
1753 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1754 struct getcpu_cache __user *cache)
1755 {
1756 int err = 0;
1757 int cpu = raw_smp_processor_id();
1758 if (cpup)
1759 err |= put_user(cpu, cpup);
1760 if (nodep)
1761 err |= put_user(cpu_to_node(cpu), nodep);
1762 if (cache) {
1763 /*
1764 * The cache is not needed for this implementation,
1765 * but make sure user programs pass something
1766 * valid. vsyscall implementations can instead make
1767 * good use of the cache. Only use t0 and t1 because
1768 * these are available in both 32bit and 64bit ABI (no
1769 * need for a compat_getcpu). 32bit has enough
1770 * padding
1771 */
1772 unsigned long t0, t1;
1773 get_user(t0, &cache->blob[0]);
1774 get_user(t1, &cache->blob[1]);
1775 t0++;
1776 t1++;
1777 put_user(t0, &cache->blob[0]);
1778 put_user(t1, &cache->blob[1]);
1779 }
1780 return err ? -EFAULT : 0;
1781 }
1782
1783 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1784
1785 static void argv_cleanup(char **argv, char **envp)
1786 {
1787 argv_free(argv);
1788 }
1789
1790 /**
1791 * orderly_poweroff - Trigger an orderly system poweroff
1792 * @force: force poweroff if command execution fails
1793 *
1794 * This may be called from any context to trigger a system shutdown.
1795 * If the orderly shutdown fails, it will force an immediate shutdown.
1796 */
1797 int orderly_poweroff(bool force)
1798 {
1799 int argc;
1800 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1801 static char *envp[] = {
1802 "HOME=/",
1803 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1804 NULL
1805 };
1806 int ret = -ENOMEM;
1807 struct subprocess_info *info;
1808
1809 if (argv == NULL) {
1810 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1811 __func__, poweroff_cmd);
1812 goto out;
1813 }
1814
1815 info = call_usermodehelper_setup(argv[0], argv, envp);
1816 if (info == NULL) {
1817 argv_free(argv);
1818 goto out;
1819 }
1820
1821 call_usermodehelper_setcleanup(info, argv_cleanup);
1822
1823 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1824
1825 out:
1826 if (ret && force) {
1827 printk(KERN_WARNING "Failed to start orderly shutdown: "
1828 "forcing the issue\n");
1829
1830 /* I guess this should try to kick off some daemon to
1831 sync and poweroff asap. Or not even bother syncing
1832 if we're doing an emergency shutdown? */
1833 emergency_sync();
1834 kernel_power_off();
1835 }
1836
1837 return ret;
1838 }
1839 EXPORT_SYMBOL_GPL(orderly_poweroff);
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