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pids: de_thread: don't clear session/pgrp pids for the old leader
[linux-2.6/mini2440.git] / kernel / sys.c
blob47c30a20b5540a00d625235001fef5240218cd76
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_task(pgrp, PIDTYPE_PGID, p) {
173 error = set_one_prio(p, niceval, error);
174 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
175 break;
176 case PRIO_USER:
177 user = current->user;
178 if (!who)
179 who = current->uid;
180 else
181 if ((who != current->uid) && !(user = find_user(who)))
182 goto out_unlock; /* No processes for this user */
183
184 do_each_thread(g, p)
185 if (p->uid == who)
186 error = set_one_prio(p, niceval, error);
187 while_each_thread(g, p);
188 if (who != current->uid)
189 free_uid(user); /* For find_user() */
190 break;
191 }
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_task(pgrp, PIDTYPE_PGID, p) {
233 niceval = 20 - task_nice(p);
234 if (niceval > retval)
235 retval = niceval;
236 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
237 break;
238 case PRIO_USER:
239 user = current->user;
240 if (!who)
241 who = current->uid;
242 else
243 if ((who != current->uid) && !(user = find_user(who)))
244 goto out_unlock; /* No processes for this user */
245
246 do_each_thread(g, p)
247 if (p->uid == who) {
248 niceval = 20 - task_nice(p);
249 if (niceval > retval)
250 retval = niceval;
251 }
252 while_each_thread(g, p);
253 if (who != current->uid)
254 free_uid(user); /* for find_user() */
255 break;
256 }
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 static 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 /**
305 * kernel_kexec - reboot the system
306 *
307 * Move into place and start executing a preloaded standalone
308 * executable. If nothing was preloaded return an error.
309 */
310 static void kernel_kexec(void)
311 {
312 #ifdef CONFIG_KEXEC
313 struct kimage *image;
314 image = xchg(&kexec_image, NULL);
315 if (!image)
316 return;
317 kernel_restart_prepare(NULL);
318 printk(KERN_EMERG "Starting new kernel\n");
319 machine_shutdown();
320 machine_kexec(image);
321 #endif
322 }
323
324 static void kernel_shutdown_prepare(enum system_states state)
325 {
326 blocking_notifier_call_chain(&reboot_notifier_list,
327 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
328 system_state = state;
329 device_shutdown();
330 }
331 /**
332 * kernel_halt - halt the system
333 *
334 * Shutdown everything and perform a clean system halt.
335 */
336 void kernel_halt(void)
337 {
338 kernel_shutdown_prepare(SYSTEM_HALT);
339 sysdev_shutdown();
340 printk(KERN_EMERG "System halted.\n");
341 machine_halt();
342 }
343
344 EXPORT_SYMBOL_GPL(kernel_halt);
345
346 /**
347 * kernel_power_off - power_off the system
348 *
349 * Shutdown everything and perform a clean system power_off.
350 */
351 void kernel_power_off(void)
352 {
353 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
354 if (pm_power_off_prepare)
355 pm_power_off_prepare();
356 disable_nonboot_cpus();
357 sysdev_shutdown();
358 printk(KERN_EMERG "Power down.\n");
359 machine_power_off();
360 }
361 EXPORT_SYMBOL_GPL(kernel_power_off);
362 /*
363 * Reboot system call: for obvious reasons only root may call it,
364 * and even root needs to set up some magic numbers in the registers
365 * so that some mistake won't make this reboot the whole machine.
366 * You can also set the meaning of the ctrl-alt-del-key here.
367 *
368 * reboot doesn't sync: do that yourself before calling this.
369 */
370 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
371 {
372 char buffer[256];
373
374 /* We only trust the superuser with rebooting the system. */
375 if (!capable(CAP_SYS_BOOT))
376 return -EPERM;
377
378 /* For safety, we require "magic" arguments. */
379 if (magic1 != LINUX_REBOOT_MAGIC1 ||
380 (magic2 != LINUX_REBOOT_MAGIC2 &&
381 magic2 != LINUX_REBOOT_MAGIC2A &&
382 magic2 != LINUX_REBOOT_MAGIC2B &&
383 magic2 != LINUX_REBOOT_MAGIC2C))
384 return -EINVAL;
385
386 /* Instead of trying to make the power_off code look like
387 * halt when pm_power_off is not set do it the easy way.
388 */
389 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
390 cmd = LINUX_REBOOT_CMD_HALT;
391
392 lock_kernel();
393 switch (cmd) {
394 case LINUX_REBOOT_CMD_RESTART:
395 kernel_restart(NULL);
396 break;
397
398 case LINUX_REBOOT_CMD_CAD_ON:
399 C_A_D = 1;
400 break;
401
402 case LINUX_REBOOT_CMD_CAD_OFF:
403 C_A_D = 0;
404 break;
405
406 case LINUX_REBOOT_CMD_HALT:
407 kernel_halt();
408 unlock_kernel();
409 do_exit(0);
410 break;
411
412 case LINUX_REBOOT_CMD_POWER_OFF:
413 kernel_power_off();
414 unlock_kernel();
415 do_exit(0);
416 break;
417
418 case LINUX_REBOOT_CMD_RESTART2:
419 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
420 unlock_kernel();
421 return -EFAULT;
422 }
423 buffer[sizeof(buffer) - 1] = '\0';
424
425 kernel_restart(buffer);
426 break;
427
428 case LINUX_REBOOT_CMD_KEXEC:
429 kernel_kexec();
430 unlock_kernel();
431 return -EINVAL;
432
433 #ifdef CONFIG_HIBERNATION
434 case LINUX_REBOOT_CMD_SW_SUSPEND:
435 {
436 int ret = hibernate();
437 unlock_kernel();
438 return ret;
439 }
440 #endif
441
442 default:
443 unlock_kernel();
444 return -EINVAL;
445 }
446 unlock_kernel();
447 return 0;
448 }
449
450 static void deferred_cad(struct work_struct *dummy)
451 {
452 kernel_restart(NULL);
453 }
454
455 /*
456 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
457 * As it's called within an interrupt, it may NOT sync: the only choice
458 * is whether to reboot at once, or just ignore the ctrl-alt-del.
459 */
460 void ctrl_alt_del(void)
461 {
462 static DECLARE_WORK(cad_work, deferred_cad);
463
464 if (C_A_D)
465 schedule_work(&cad_work);
466 else
467 kill_cad_pid(SIGINT, 1);
468 }
469
470 /*
471 * Unprivileged users may change the real gid to the effective gid
472 * or vice versa. (BSD-style)
473 *
474 * If you set the real gid at all, or set the effective gid to a value not
475 * equal to the real gid, then the saved gid is set to the new effective gid.
476 *
477 * This makes it possible for a setgid program to completely drop its
478 * privileges, which is often a useful assertion to make when you are doing
479 * a security audit over a program.
480 *
481 * The general idea is that a program which uses just setregid() will be
482 * 100% compatible with BSD. A program which uses just setgid() will be
483 * 100% compatible with POSIX with saved IDs.
484 *
485 * SMP: There are not races, the GIDs are checked only by filesystem
486 * operations (as far as semantic preservation is concerned).
487 */
488 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
489 {
490 int old_rgid = current->gid;
491 int old_egid = current->egid;
492 int new_rgid = old_rgid;
493 int new_egid = old_egid;
494 int retval;
495
496 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
497 if (retval)
498 return retval;
499
500 if (rgid != (gid_t) -1) {
501 if ((old_rgid == rgid) ||
502 (current->egid==rgid) ||
503 capable(CAP_SETGID))
504 new_rgid = rgid;
505 else
506 return -EPERM;
507 }
508 if (egid != (gid_t) -1) {
509 if ((old_rgid == egid) ||
510 (current->egid == egid) ||
511 (current->sgid == egid) ||
512 capable(CAP_SETGID))
513 new_egid = egid;
514 else
515 return -EPERM;
516 }
517 if (new_egid != old_egid) {
518 set_dumpable(current->mm, suid_dumpable);
519 smp_wmb();
520 }
521 if (rgid != (gid_t) -1 ||
522 (egid != (gid_t) -1 && egid != old_rgid))
523 current->sgid = new_egid;
524 current->fsgid = new_egid;
525 current->egid = new_egid;
526 current->gid = new_rgid;
527 key_fsgid_changed(current);
528 proc_id_connector(current, PROC_EVENT_GID);
529 return 0;
530 }
531
532 /*
533 * setgid() is implemented like SysV w/ SAVED_IDS
534 *
535 * SMP: Same implicit races as above.
536 */
537 asmlinkage long sys_setgid(gid_t gid)
538 {
539 int old_egid = current->egid;
540 int retval;
541
542 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
543 if (retval)
544 return retval;
545
546 if (capable(CAP_SETGID)) {
547 if (old_egid != gid) {
548 set_dumpable(current->mm, suid_dumpable);
549 smp_wmb();
550 }
551 current->gid = current->egid = current->sgid = current->fsgid = gid;
552 } else if ((gid == current->gid) || (gid == current->sgid)) {
553 if (old_egid != gid) {
554 set_dumpable(current->mm, suid_dumpable);
555 smp_wmb();
556 }
557 current->egid = current->fsgid = gid;
558 }
559 else
560 return -EPERM;
561
562 key_fsgid_changed(current);
563 proc_id_connector(current, PROC_EVENT_GID);
564 return 0;
565 }
566
567 static int set_user(uid_t new_ruid, int dumpclear)
568 {
569 struct user_struct *new_user;
570
571 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
572 if (!new_user)
573 return -EAGAIN;
574
575 if (atomic_read(&new_user->processes) >=
576 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
577 new_user != current->nsproxy->user_ns->root_user) {
578 free_uid(new_user);
579 return -EAGAIN;
580 }
581
582 switch_uid(new_user);
583
584 if (dumpclear) {
585 set_dumpable(current->mm, suid_dumpable);
586 smp_wmb();
587 }
588 current->uid = new_ruid;
589 return 0;
590 }
591
592 /*
593 * Unprivileged users may change the real uid to the effective uid
594 * or vice versa. (BSD-style)
595 *
596 * If you set the real uid at all, or set the effective uid to a value not
597 * equal to the real uid, then the saved uid is set to the new effective uid.
598 *
599 * This makes it possible for a setuid program to completely drop its
600 * privileges, which is often a useful assertion to make when you are doing
601 * a security audit over a program.
602 *
603 * The general idea is that a program which uses just setreuid() will be
604 * 100% compatible with BSD. A program which uses just setuid() will be
605 * 100% compatible with POSIX with saved IDs.
606 */
607 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
608 {
609 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
610 int retval;
611
612 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
613 if (retval)
614 return retval;
615
616 new_ruid = old_ruid = current->uid;
617 new_euid = old_euid = current->euid;
618 old_suid = current->suid;
619
620 if (ruid != (uid_t) -1) {
621 new_ruid = ruid;
622 if ((old_ruid != ruid) &&
623 (current->euid != ruid) &&
624 !capable(CAP_SETUID))
625 return -EPERM;
626 }
627
628 if (euid != (uid_t) -1) {
629 new_euid = euid;
630 if ((old_ruid != euid) &&
631 (current->euid != euid) &&
632 (current->suid != euid) &&
633 !capable(CAP_SETUID))
634 return -EPERM;
635 }
636
637 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
638 return -EAGAIN;
639
640 if (new_euid != old_euid) {
641 set_dumpable(current->mm, suid_dumpable);
642 smp_wmb();
643 }
644 current->fsuid = current->euid = new_euid;
645 if (ruid != (uid_t) -1 ||
646 (euid != (uid_t) -1 && euid != old_ruid))
647 current->suid = current->euid;
648 current->fsuid = current->euid;
649
650 key_fsuid_changed(current);
651 proc_id_connector(current, PROC_EVENT_UID);
652
653 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
654 }
655
656
657
658 /*
659 * setuid() is implemented like SysV with SAVED_IDS
660 *
661 * Note that SAVED_ID's is deficient in that a setuid root program
662 * like sendmail, for example, cannot set its uid to be a normal
663 * user and then switch back, because if you're root, setuid() sets
664 * the saved uid too. If you don't like this, blame the bright people
665 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
666 * will allow a root program to temporarily drop privileges and be able to
667 * regain them by swapping the real and effective uid.
668 */
669 asmlinkage long sys_setuid(uid_t uid)
670 {
671 int old_euid = current->euid;
672 int old_ruid, old_suid, new_suid;
673 int retval;
674
675 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
676 if (retval)
677 return retval;
678
679 old_ruid = current->uid;
680 old_suid = current->suid;
681 new_suid = old_suid;
682
683 if (capable(CAP_SETUID)) {
684 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
685 return -EAGAIN;
686 new_suid = uid;
687 } else if ((uid != current->uid) && (uid != new_suid))
688 return -EPERM;
689
690 if (old_euid != uid) {
691 set_dumpable(current->mm, suid_dumpable);
692 smp_wmb();
693 }
694 current->fsuid = current->euid = uid;
695 current->suid = new_suid;
696
697 key_fsuid_changed(current);
698 proc_id_connector(current, PROC_EVENT_UID);
699
700 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
701 }
702
703
704 /*
705 * This function implements a generic ability to update ruid, euid,
706 * and suid. This allows you to implement the 4.4 compatible seteuid().
707 */
708 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
709 {
710 int old_ruid = current->uid;
711 int old_euid = current->euid;
712 int old_suid = current->suid;
713 int retval;
714
715 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
716 if (retval)
717 return retval;
718
719 if (!capable(CAP_SETUID)) {
720 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
721 (ruid != current->euid) && (ruid != current->suid))
722 return -EPERM;
723 if ((euid != (uid_t) -1) && (euid != current->uid) &&
724 (euid != current->euid) && (euid != current->suid))
725 return -EPERM;
726 if ((suid != (uid_t) -1) && (suid != current->uid) &&
727 (suid != current->euid) && (suid != current->suid))
728 return -EPERM;
729 }
730 if (ruid != (uid_t) -1) {
731 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
732 return -EAGAIN;
733 }
734 if (euid != (uid_t) -1) {
735 if (euid != current->euid) {
736 set_dumpable(current->mm, suid_dumpable);
737 smp_wmb();
738 }
739 current->euid = euid;
740 }
741 current->fsuid = current->euid;
742 if (suid != (uid_t) -1)
743 current->suid = suid;
744
745 key_fsuid_changed(current);
746 proc_id_connector(current, PROC_EVENT_UID);
747
748 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
749 }
750
751 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
752 {
753 int retval;
754
755 if (!(retval = put_user(current->uid, ruid)) &&
756 !(retval = put_user(current->euid, euid)))
757 retval = put_user(current->suid, suid);
758
759 return retval;
760 }
761
762 /*
763 * Same as above, but for rgid, egid, sgid.
764 */
765 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
766 {
767 int retval;
768
769 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
770 if (retval)
771 return retval;
772
773 if (!capable(CAP_SETGID)) {
774 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
775 (rgid != current->egid) && (rgid != current->sgid))
776 return -EPERM;
777 if ((egid != (gid_t) -1) && (egid != current->gid) &&
778 (egid != current->egid) && (egid != current->sgid))
779 return -EPERM;
780 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
781 (sgid != current->egid) && (sgid != current->sgid))
782 return -EPERM;
783 }
784 if (egid != (gid_t) -1) {
785 if (egid != current->egid) {
786 set_dumpable(current->mm, suid_dumpable);
787 smp_wmb();
788 }
789 current->egid = egid;
790 }
791 current->fsgid = current->egid;
792 if (rgid != (gid_t) -1)
793 current->gid = rgid;
794 if (sgid != (gid_t) -1)
795 current->sgid = sgid;
796
797 key_fsgid_changed(current);
798 proc_id_connector(current, PROC_EVENT_GID);
799 return 0;
800 }
801
802 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
803 {
804 int retval;
805
806 if (!(retval = put_user(current->gid, rgid)) &&
807 !(retval = put_user(current->egid, egid)))
808 retval = put_user(current->sgid, sgid);
809
810 return retval;
811 }
812
813
814 /*
815 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
816 * is used for "access()" and for the NFS daemon (letting nfsd stay at
817 * whatever uid it wants to). It normally shadows "euid", except when
818 * explicitly set by setfsuid() or for access..
819 */
820 asmlinkage long sys_setfsuid(uid_t uid)
821 {
822 int old_fsuid;
823
824 old_fsuid = current->fsuid;
825 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
826 return old_fsuid;
827
828 if (uid == current->uid || uid == current->euid ||
829 uid == current->suid || uid == current->fsuid ||
830 capable(CAP_SETUID)) {
831 if (uid != old_fsuid) {
832 set_dumpable(current->mm, suid_dumpable);
833 smp_wmb();
834 }
835 current->fsuid = uid;
836 }
837
838 key_fsuid_changed(current);
839 proc_id_connector(current, PROC_EVENT_UID);
840
841 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
842
843 return old_fsuid;
844 }
845
846 /*
847 * Samma på svenska..
848 */
849 asmlinkage long sys_setfsgid(gid_t gid)
850 {
851 int old_fsgid;
852
853 old_fsgid = current->fsgid;
854 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
855 return old_fsgid;
856
857 if (gid == current->gid || gid == current->egid ||
858 gid == current->sgid || gid == current->fsgid ||
859 capable(CAP_SETGID)) {
860 if (gid != old_fsgid) {
861 set_dumpable(current->mm, suid_dumpable);
862 smp_wmb();
863 }
864 current->fsgid = gid;
865 key_fsgid_changed(current);
866 proc_id_connector(current, PROC_EVENT_GID);
867 }
868 return old_fsgid;
869 }
870
871 asmlinkage long sys_times(struct tms __user * tbuf)
872 {
873 /*
874 * In the SMP world we might just be unlucky and have one of
875 * the times increment as we use it. Since the value is an
876 * atomically safe type this is just fine. Conceptually its
877 * as if the syscall took an instant longer to occur.
878 */
879 if (tbuf) {
880 struct tms tmp;
881 struct task_struct *tsk = current;
882 struct task_struct *t;
883 cputime_t utime, stime, cutime, cstime;
884
885 spin_lock_irq(&tsk->sighand->siglock);
886 utime = tsk->signal->utime;
887 stime = tsk->signal->stime;
888 t = tsk;
889 do {
890 utime = cputime_add(utime, t->utime);
891 stime = cputime_add(stime, t->stime);
892 t = next_thread(t);
893 } while (t != tsk);
894
895 cutime = tsk->signal->cutime;
896 cstime = tsk->signal->cstime;
897 spin_unlock_irq(&tsk->sighand->siglock);
898
899 tmp.tms_utime = cputime_to_clock_t(utime);
900 tmp.tms_stime = cputime_to_clock_t(stime);
901 tmp.tms_cutime = cputime_to_clock_t(cutime);
902 tmp.tms_cstime = cputime_to_clock_t(cstime);
903 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
904 return -EFAULT;
905 }
906 return (long) jiffies_64_to_clock_t(get_jiffies_64());
907 }
908
909 /*
910 * This needs some heavy checking ...
911 * I just haven't the stomach for it. I also don't fully
912 * understand sessions/pgrp etc. Let somebody who does explain it.
913 *
914 * OK, I think I have the protection semantics right.... this is really
915 * only important on a multi-user system anyway, to make sure one user
916 * can't send a signal to a process owned by another. -TYT, 12/12/91
917 *
918 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
919 * LBT 04.03.94
920 */
921 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
922 {
923 struct task_struct *p;
924 struct task_struct *group_leader = current->group_leader;
925 struct pid *pgrp;
926 int err;
927
928 if (!pid)
929 pid = task_pid_vnr(group_leader);
930 if (!pgid)
931 pgid = pid;
932 if (pgid < 0)
933 return -EINVAL;
934
935 /* From this point forward we keep holding onto the tasklist lock
936 * so that our parent does not change from under us. -DaveM
937 */
938 write_lock_irq(&tasklist_lock);
939
940 err = -ESRCH;
941 p = find_task_by_vpid(pid);
942 if (!p)
943 goto out;
944
945 err = -EINVAL;
946 if (!thread_group_leader(p))
947 goto out;
948
949 if (same_thread_group(p->real_parent, group_leader)) {
950 err = -EPERM;
951 if (task_session(p) != task_session(group_leader))
952 goto out;
953 err = -EACCES;
954 if (p->did_exec)
955 goto out;
956 } else {
957 err = -ESRCH;
958 if (p != group_leader)
959 goto out;
960 }
961
962 err = -EPERM;
963 if (p->signal->leader)
964 goto out;
965
966 pgrp = task_pid(p);
967 if (pgid != pid) {
968 struct task_struct *g;
969
970 pgrp = find_vpid(pgid);
971 g = pid_task(pgrp, PIDTYPE_PGID);
972 if (!g || task_session(g) != task_session(group_leader))
973 goto out;
974 }
975
976 err = security_task_setpgid(p, pgid);
977 if (err)
978 goto out;
979
980 if (task_pgrp(p) != pgrp) {
981 detach_pid(p, PIDTYPE_PGID);
982 attach_pid(p, PIDTYPE_PGID, pgrp);
983 set_task_pgrp(p, pid_nr(pgrp));
984 }
985
986 err = 0;
987 out:
988 /* All paths lead to here, thus we are safe. -DaveM */
989 write_unlock_irq(&tasklist_lock);
990 return err;
991 }
992
993 asmlinkage long sys_getpgid(pid_t pid)
994 {
995 if (!pid)
996 return task_pgrp_vnr(current);
997 else {
998 int retval;
999 struct task_struct *p;
1000
1001 read_lock(&tasklist_lock);
1002 p = find_task_by_vpid(pid);
1003 retval = -ESRCH;
1004 if (p) {
1005 retval = security_task_getpgid(p);
1006 if (!retval)
1007 retval = task_pgrp_vnr(p);
1008 }
1009 read_unlock(&tasklist_lock);
1010 return retval;
1011 }
1012 }
1013
1014 #ifdef __ARCH_WANT_SYS_GETPGRP
1015
1016 asmlinkage long sys_getpgrp(void)
1017 {
1018 /* SMP - assuming writes are word atomic this is fine */
1019 return task_pgrp_vnr(current);
1020 }
1021
1022 #endif
1023
1024 asmlinkage long sys_getsid(pid_t pid)
1025 {
1026 if (!pid)
1027 return task_session_vnr(current);
1028 else {
1029 int retval;
1030 struct task_struct *p;
1031
1032 rcu_read_lock();
1033 p = find_task_by_vpid(pid);
1034 retval = -ESRCH;
1035 if (p) {
1036 retval = security_task_getsid(p);
1037 if (!retval)
1038 retval = task_session_vnr(p);
1039 }
1040 rcu_read_unlock();
1041 return retval;
1042 }
1043 }
1044
1045 asmlinkage long sys_setsid(void)
1046 {
1047 struct task_struct *group_leader = current->group_leader;
1048 struct pid *sid = task_pid(group_leader);
1049 pid_t session = pid_vnr(sid);
1050 int err = -EPERM;
1051
1052 write_lock_irq(&tasklist_lock);
1053 /* Fail if I am already a session leader */
1054 if (group_leader->signal->leader)
1055 goto out;
1056
1057 /* Fail if a process group id already exists that equals the
1058 * proposed session id.
1059 */
1060 if (pid_task(sid, PIDTYPE_PGID))
1061 goto out;
1062
1063 group_leader->signal->leader = 1;
1064 __set_special_pids(sid);
1065
1066 spin_lock(&group_leader->sighand->siglock);
1067 group_leader->signal->tty = NULL;
1068 spin_unlock(&group_leader->sighand->siglock);
1069
1070 err = session;
1071 out:
1072 write_unlock_irq(&tasklist_lock);
1073 return err;
1074 }
1075
1076 /*
1077 * Supplementary group IDs
1078 */
1079
1080 /* init to 2 - one for init_task, one to ensure it is never freed */
1081 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1082
1083 struct group_info *groups_alloc(int gidsetsize)
1084 {
1085 struct group_info *group_info;
1086 int nblocks;
1087 int i;
1088
1089 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1090 /* Make sure we always allocate at least one indirect block pointer */
1091 nblocks = nblocks ? : 1;
1092 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1093 if (!group_info)
1094 return NULL;
1095 group_info->ngroups = gidsetsize;
1096 group_info->nblocks = nblocks;
1097 atomic_set(&group_info->usage, 1);
1098
1099 if (gidsetsize <= NGROUPS_SMALL)
1100 group_info->blocks[0] = group_info->small_block;
1101 else {
1102 for (i = 0; i < nblocks; i++) {
1103 gid_t *b;
1104 b = (void *)__get_free_page(GFP_USER);
1105 if (!b)
1106 goto out_undo_partial_alloc;
1107 group_info->blocks[i] = b;
1108 }
1109 }
1110 return group_info;
1111
1112 out_undo_partial_alloc:
1113 while (--i >= 0) {
1114 free_page((unsigned long)group_info->blocks[i]);
1115 }
1116 kfree(group_info);
1117 return NULL;
1118 }
1119
1120 EXPORT_SYMBOL(groups_alloc);
1121
1122 void groups_free(struct group_info *group_info)
1123 {
1124 if (group_info->blocks[0] != group_info->small_block) {
1125 int i;
1126 for (i = 0; i < group_info->nblocks; i++)
1127 free_page((unsigned long)group_info->blocks[i]);
1128 }
1129 kfree(group_info);
1130 }
1131
1132 EXPORT_SYMBOL(groups_free);
1133
1134 /* export the group_info to a user-space array */
1135 static int groups_to_user(gid_t __user *grouplist,
1136 struct group_info *group_info)
1137 {
1138 int i;
1139 unsigned int count = group_info->ngroups;
1140
1141 for (i = 0; i < group_info->nblocks; i++) {
1142 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1143 unsigned int len = cp_count * sizeof(*grouplist);
1144
1145 if (copy_to_user(grouplist, group_info->blocks[i], len))
1146 return -EFAULT;
1147
1148 grouplist += NGROUPS_PER_BLOCK;
1149 count -= cp_count;
1150 }
1151 return 0;
1152 }
1153
1154 /* fill a group_info from a user-space array - it must be allocated already */
1155 static int groups_from_user(struct group_info *group_info,
1156 gid_t __user *grouplist)
1157 {
1158 int i;
1159 unsigned int count = group_info->ngroups;
1160
1161 for (i = 0; i < group_info->nblocks; i++) {
1162 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1163 unsigned int len = cp_count * sizeof(*grouplist);
1164
1165 if (copy_from_user(group_info->blocks[i], grouplist, len))
1166 return -EFAULT;
1167
1168 grouplist += NGROUPS_PER_BLOCK;
1169 count -= cp_count;
1170 }
1171 return 0;
1172 }
1173
1174 /* a simple Shell sort */
1175 static void groups_sort(struct group_info *group_info)
1176 {
1177 int base, max, stride;
1178 int gidsetsize = group_info->ngroups;
1179
1180 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1181 ; /* nothing */
1182 stride /= 3;
1183
1184 while (stride) {
1185 max = gidsetsize - stride;
1186 for (base = 0; base < max; base++) {
1187 int left = base;
1188 int right = left + stride;
1189 gid_t tmp = GROUP_AT(group_info, right);
1190
1191 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1192 GROUP_AT(group_info, right) =
1193 GROUP_AT(group_info, left);
1194 right = left;
1195 left -= stride;
1196 }
1197 GROUP_AT(group_info, right) = tmp;
1198 }
1199 stride /= 3;
1200 }
1201 }
1202
1203 /* a simple bsearch */
1204 int groups_search(struct group_info *group_info, gid_t grp)
1205 {
1206 unsigned int left, right;
1207
1208 if (!group_info)
1209 return 0;
1210
1211 left = 0;
1212 right = group_info->ngroups;
1213 while (left < right) {
1214 unsigned int mid = (left+right)/2;
1215 int cmp = grp - GROUP_AT(group_info, mid);
1216 if (cmp > 0)
1217 left = mid + 1;
1218 else if (cmp < 0)
1219 right = mid;
1220 else
1221 return 1;
1222 }
1223 return 0;
1224 }
1225
1226 /* validate and set current->group_info */
1227 int set_current_groups(struct group_info *group_info)
1228 {
1229 int retval;
1230 struct group_info *old_info;
1231
1232 retval = security_task_setgroups(group_info);
1233 if (retval)
1234 return retval;
1235
1236 groups_sort(group_info);
1237 get_group_info(group_info);
1238
1239 task_lock(current);
1240 old_info = current->group_info;
1241 current->group_info = group_info;
1242 task_unlock(current);
1243
1244 put_group_info(old_info);
1245
1246 return 0;
1247 }
1248
1249 EXPORT_SYMBOL(set_current_groups);
1250
1251 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1252 {
1253 int i = 0;
1254
1255 /*
1256 * SMP: Nobody else can change our grouplist. Thus we are
1257 * safe.
1258 */
1259
1260 if (gidsetsize < 0)
1261 return -EINVAL;
1262
1263 /* no need to grab task_lock here; it cannot change */
1264 i = current->group_info->ngroups;
1265 if (gidsetsize) {
1266 if (i > gidsetsize) {
1267 i = -EINVAL;
1268 goto out;
1269 }
1270 if (groups_to_user(grouplist, current->group_info)) {
1271 i = -EFAULT;
1272 goto out;
1273 }
1274 }
1275 out:
1276 return i;
1277 }
1278
1279 /*
1280 * SMP: Our groups are copy-on-write. We can set them safely
1281 * without another task interfering.
1282 */
1283
1284 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1285 {
1286 struct group_info *group_info;
1287 int retval;
1288
1289 if (!capable(CAP_SETGID))
1290 return -EPERM;
1291 if ((unsigned)gidsetsize > NGROUPS_MAX)
1292 return -EINVAL;
1293
1294 group_info = groups_alloc(gidsetsize);
1295 if (!group_info)
1296 return -ENOMEM;
1297 retval = groups_from_user(group_info, grouplist);
1298 if (retval) {
1299 put_group_info(group_info);
1300 return retval;
1301 }
1302
1303 retval = set_current_groups(group_info);
1304 put_group_info(group_info);
1305
1306 return retval;
1307 }
1308
1309 /*
1310 * Check whether we're fsgid/egid or in the supplemental group..
1311 */
1312 int in_group_p(gid_t grp)
1313 {
1314 int retval = 1;
1315 if (grp != current->fsgid)
1316 retval = groups_search(current->group_info, grp);
1317 return retval;
1318 }
1319
1320 EXPORT_SYMBOL(in_group_p);
1321
1322 int in_egroup_p(gid_t grp)
1323 {
1324 int retval = 1;
1325 if (grp != current->egid)
1326 retval = groups_search(current->group_info, grp);
1327 return retval;
1328 }
1329
1330 EXPORT_SYMBOL(in_egroup_p);
1331
1332 DECLARE_RWSEM(uts_sem);
1333
1334 EXPORT_SYMBOL(uts_sem);
1335
1336 asmlinkage long sys_newuname(struct new_utsname __user * name)
1337 {
1338 int errno = 0;
1339
1340 down_read(&uts_sem);
1341 if (copy_to_user(name, utsname(), sizeof *name))
1342 errno = -EFAULT;
1343 up_read(&uts_sem);
1344 return errno;
1345 }
1346
1347 asmlinkage long sys_sethostname(char __user *name, int len)
1348 {
1349 int errno;
1350 char tmp[__NEW_UTS_LEN];
1351
1352 if (!capable(CAP_SYS_ADMIN))
1353 return -EPERM;
1354 if (len < 0 || len > __NEW_UTS_LEN)
1355 return -EINVAL;
1356 down_write(&uts_sem);
1357 errno = -EFAULT;
1358 if (!copy_from_user(tmp, name, len)) {
1359 memcpy(utsname()->nodename, tmp, len);
1360 utsname()->nodename[len] = 0;
1361 errno = 0;
1362 }
1363 up_write(&uts_sem);
1364 return errno;
1365 }
1366
1367 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1368
1369 asmlinkage long sys_gethostname(char __user *name, int len)
1370 {
1371 int i, errno;
1372
1373 if (len < 0)
1374 return -EINVAL;
1375 down_read(&uts_sem);
1376 i = 1 + strlen(utsname()->nodename);
1377 if (i > len)
1378 i = len;
1379 errno = 0;
1380 if (copy_to_user(name, utsname()->nodename, i))
1381 errno = -EFAULT;
1382 up_read(&uts_sem);
1383 return errno;
1384 }
1385
1386 #endif
1387
1388 /*
1389 * Only setdomainname; getdomainname can be implemented by calling
1390 * uname()
1391 */
1392 asmlinkage long sys_setdomainname(char __user *name, int len)
1393 {
1394 int errno;
1395 char tmp[__NEW_UTS_LEN];
1396
1397 if (!capable(CAP_SYS_ADMIN))
1398 return -EPERM;
1399 if (len < 0 || len > __NEW_UTS_LEN)
1400 return -EINVAL;
1401
1402 down_write(&uts_sem);
1403 errno = -EFAULT;
1404 if (!copy_from_user(tmp, name, len)) {
1405 memcpy(utsname()->domainname, tmp, len);
1406 utsname()->domainname[len] = 0;
1407 errno = 0;
1408 }
1409 up_write(&uts_sem);
1410 return errno;
1411 }
1412
1413 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1414 {
1415 if (resource >= RLIM_NLIMITS)
1416 return -EINVAL;
1417 else {
1418 struct rlimit value;
1419 task_lock(current->group_leader);
1420 value = current->signal->rlim[resource];
1421 task_unlock(current->group_leader);
1422 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1423 }
1424 }
1425
1426 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1427
1428 /*
1429 * Back compatibility for getrlimit. Needed for some apps.
1430 */
1431
1432 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1433 {
1434 struct rlimit x;
1435 if (resource >= RLIM_NLIMITS)
1436 return -EINVAL;
1437
1438 task_lock(current->group_leader);
1439 x = current->signal->rlim[resource];
1440 task_unlock(current->group_leader);
1441 if (x.rlim_cur > 0x7FFFFFFF)
1442 x.rlim_cur = 0x7FFFFFFF;
1443 if (x.rlim_max > 0x7FFFFFFF)
1444 x.rlim_max = 0x7FFFFFFF;
1445 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1446 }
1447
1448 #endif
1449
1450 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1451 {
1452 struct rlimit new_rlim, *old_rlim;
1453 unsigned long it_prof_secs;
1454 int retval;
1455
1456 if (resource >= RLIM_NLIMITS)
1457 return -EINVAL;
1458 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1459 return -EFAULT;
1460 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1461 return -EINVAL;
1462 old_rlim = current->signal->rlim + resource;
1463 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1464 !capable(CAP_SYS_RESOURCE))
1465 return -EPERM;
1466 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1467 return -EPERM;
1468
1469 retval = security_task_setrlimit(resource, &new_rlim);
1470 if (retval)
1471 return retval;
1472
1473 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1474 /*
1475 * The caller is asking for an immediate RLIMIT_CPU
1476 * expiry. But we use the zero value to mean "it was
1477 * never set". So let's cheat and make it one second
1478 * instead
1479 */
1480 new_rlim.rlim_cur = 1;
1481 }
1482
1483 task_lock(current->group_leader);
1484 *old_rlim = new_rlim;
1485 task_unlock(current->group_leader);
1486
1487 if (resource != RLIMIT_CPU)
1488 goto out;
1489
1490 /*
1491 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1492 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1493 * very long-standing error, and fixing it now risks breakage of
1494 * applications, so we live with it
1495 */
1496 if (new_rlim.rlim_cur == RLIM_INFINITY)
1497 goto out;
1498
1499 it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1500 if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1501 unsigned long rlim_cur = new_rlim.rlim_cur;
1502 cputime_t cputime;
1503
1504 cputime = secs_to_cputime(rlim_cur);
1505 read_lock(&tasklist_lock);
1506 spin_lock_irq(&current->sighand->siglock);
1507 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1508 spin_unlock_irq(&current->sighand->siglock);
1509 read_unlock(&tasklist_lock);
1510 }
1511 out:
1512 return 0;
1513 }
1514
1515 /*
1516 * It would make sense to put struct rusage in the task_struct,
1517 * except that would make the task_struct be *really big*. After
1518 * task_struct gets moved into malloc'ed memory, it would
1519 * make sense to do this. It will make moving the rest of the information
1520 * a lot simpler! (Which we're not doing right now because we're not
1521 * measuring them yet).
1522 *
1523 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1524 * races with threads incrementing their own counters. But since word
1525 * reads are atomic, we either get new values or old values and we don't
1526 * care which for the sums. We always take the siglock to protect reading
1527 * the c* fields from p->signal from races with exit.c updating those
1528 * fields when reaping, so a sample either gets all the additions of a
1529 * given child after it's reaped, or none so this sample is before reaping.
1530 *
1531 * Locking:
1532 * We need to take the siglock for CHILDEREN, SELF and BOTH
1533 * for the cases current multithreaded, non-current single threaded
1534 * non-current multithreaded. Thread traversal is now safe with
1535 * the siglock held.
1536 * Strictly speaking, we donot need to take the siglock if we are current and
1537 * single threaded, as no one else can take our signal_struct away, no one
1538 * else can reap the children to update signal->c* counters, and no one else
1539 * can race with the signal-> fields. If we do not take any lock, the
1540 * signal-> fields could be read out of order while another thread was just
1541 * exiting. So we should place a read memory barrier when we avoid the lock.
1542 * On the writer side, write memory barrier is implied in __exit_signal
1543 * as __exit_signal releases the siglock spinlock after updating the signal->
1544 * fields. But we don't do this yet to keep things simple.
1545 *
1546 */
1547
1548 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
1549 cputime_t *utimep, cputime_t *stimep)
1550 {
1551 *utimep = cputime_add(*utimep, t->utime);
1552 *stimep = cputime_add(*stimep, t->stime);
1553 r->ru_nvcsw += t->nvcsw;
1554 r->ru_nivcsw += t->nivcsw;
1555 r->ru_minflt += t->min_flt;
1556 r->ru_majflt += t->maj_flt;
1557 r->ru_inblock += task_io_get_inblock(t);
1558 r->ru_oublock += task_io_get_oublock(t);
1559 }
1560
1561 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1562 {
1563 struct task_struct *t;
1564 unsigned long flags;
1565 cputime_t utime, stime;
1566
1567 memset((char *) r, 0, sizeof *r);
1568 utime = stime = cputime_zero;
1569
1570 if (who == RUSAGE_THREAD) {
1571 accumulate_thread_rusage(p, r, &utime, &stime);
1572 goto out;
1573 }
1574
1575 if (!lock_task_sighand(p, &flags))
1576 return;
1577
1578 switch (who) {
1579 case RUSAGE_BOTH:
1580 case RUSAGE_CHILDREN:
1581 utime = p->signal->cutime;
1582 stime = p->signal->cstime;
1583 r->ru_nvcsw = p->signal->cnvcsw;
1584 r->ru_nivcsw = p->signal->cnivcsw;
1585 r->ru_minflt = p->signal->cmin_flt;
1586 r->ru_majflt = p->signal->cmaj_flt;
1587 r->ru_inblock = p->signal->cinblock;
1588 r->ru_oublock = p->signal->coublock;
1589
1590 if (who == RUSAGE_CHILDREN)
1591 break;
1592
1593 case RUSAGE_SELF:
1594 utime = cputime_add(utime, p->signal->utime);
1595 stime = cputime_add(stime, p->signal->stime);
1596 r->ru_nvcsw += p->signal->nvcsw;
1597 r->ru_nivcsw += p->signal->nivcsw;
1598 r->ru_minflt += p->signal->min_flt;
1599 r->ru_majflt += p->signal->maj_flt;
1600 r->ru_inblock += p->signal->inblock;
1601 r->ru_oublock += p->signal->oublock;
1602 t = p;
1603 do {
1604 accumulate_thread_rusage(t, r, &utime, &stime);
1605 t = next_thread(t);
1606 } while (t != p);
1607 break;
1608
1609 default:
1610 BUG();
1611 }
1612 unlock_task_sighand(p, &flags);
1613
1614 out:
1615 cputime_to_timeval(utime, &r->ru_utime);
1616 cputime_to_timeval(stime, &r->ru_stime);
1617 }
1618
1619 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1620 {
1621 struct rusage r;
1622 k_getrusage(p, who, &r);
1623 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1624 }
1625
1626 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1627 {
1628 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1629 who != RUSAGE_THREAD)
1630 return -EINVAL;
1631 return getrusage(current, who, ru);
1632 }
1633
1634 asmlinkage long sys_umask(int mask)
1635 {
1636 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1637 return mask;
1638 }
1639
1640 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1641 unsigned long arg4, unsigned long arg5)
1642 {
1643 long uninitialized_var(error);
1644
1645 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1646 return error;
1647
1648 switch (option) {
1649 case PR_SET_PDEATHSIG:
1650 if (!valid_signal(arg2)) {
1651 error = -EINVAL;
1652 break;
1653 }
1654 current->pdeath_signal = arg2;
1655 break;
1656 case PR_GET_PDEATHSIG:
1657 error = put_user(current->pdeath_signal, (int __user *)arg2);
1658 break;
1659 case PR_GET_DUMPABLE:
1660 error = get_dumpable(current->mm);
1661 break;
1662 case PR_SET_DUMPABLE:
1663 if (arg2 < 0 || arg2 > 1) {
1664 error = -EINVAL;
1665 break;
1666 }
1667 set_dumpable(current->mm, arg2);
1668 break;
1669
1670 case PR_SET_UNALIGN:
1671 error = SET_UNALIGN_CTL(current, arg2);
1672 break;
1673 case PR_GET_UNALIGN:
1674 error = GET_UNALIGN_CTL(current, arg2);
1675 break;
1676 case PR_SET_FPEMU:
1677 error = SET_FPEMU_CTL(current, arg2);
1678 break;
1679 case PR_GET_FPEMU:
1680 error = GET_FPEMU_CTL(current, arg2);
1681 break;
1682 case PR_SET_FPEXC:
1683 error = SET_FPEXC_CTL(current, arg2);
1684 break;
1685 case PR_GET_FPEXC:
1686 error = GET_FPEXC_CTL(current, arg2);
1687 break;
1688 case PR_GET_TIMING:
1689 error = PR_TIMING_STATISTICAL;
1690 break;
1691 case PR_SET_TIMING:
1692 if (arg2 == PR_TIMING_STATISTICAL)
1693 error = 0;
1694 else
1695 error = -EINVAL;
1696 break;
1697
1698 case PR_SET_NAME: {
1699 struct task_struct *me = current;
1700 unsigned char ncomm[sizeof(me->comm)];
1701
1702 ncomm[sizeof(me->comm)-1] = 0;
1703 if (strncpy_from_user(ncomm, (char __user *)arg2,
1704 sizeof(me->comm)-1) < 0)
1705 return -EFAULT;
1706 set_task_comm(me, ncomm);
1707 return 0;
1708 }
1709 case PR_GET_NAME: {
1710 struct task_struct *me = current;
1711 unsigned char tcomm[sizeof(me->comm)];
1712
1713 get_task_comm(tcomm, me);
1714 if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1715 return -EFAULT;
1716 return 0;
1717 }
1718 case PR_GET_ENDIAN:
1719 error = GET_ENDIAN(current, arg2);
1720 break;
1721 case PR_SET_ENDIAN:
1722 error = SET_ENDIAN(current, arg2);
1723 break;
1724
1725 case PR_GET_SECCOMP:
1726 error = prctl_get_seccomp();
1727 break;
1728 case PR_SET_SECCOMP:
1729 error = prctl_set_seccomp(arg2);
1730 break;
1731 case PR_GET_TSC:
1732 error = GET_TSC_CTL(arg2);
1733 break;
1734 case PR_SET_TSC:
1735 error = SET_TSC_CTL(arg2);
1736 break;
1737 default:
1738 error = -EINVAL;
1739 break;
1740 }
1741 return error;
1742 }
1743
1744 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1745 struct getcpu_cache __user *unused)
1746 {
1747 int err = 0;
1748 int cpu = raw_smp_processor_id();
1749 if (cpup)
1750 err |= put_user(cpu, cpup);
1751 if (nodep)
1752 err |= put_user(cpu_to_node(cpu), nodep);
1753 return err ? -EFAULT : 0;
1754 }
1755
1756 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1757
1758 static void argv_cleanup(char **argv, char **envp)
1759 {
1760 argv_free(argv);
1761 }
1762
1763 /**
1764 * orderly_poweroff - Trigger an orderly system poweroff
1765 * @force: force poweroff if command execution fails
1766 *
1767 * This may be called from any context to trigger a system shutdown.
1768 * If the orderly shutdown fails, it will force an immediate shutdown.
1769 */
1770 int orderly_poweroff(bool force)
1771 {
1772 int argc;
1773 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1774 static char *envp[] = {
1775 "HOME=/",
1776 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1777 NULL
1778 };
1779 int ret = -ENOMEM;
1780 struct subprocess_info *info;
1781
1782 if (argv == NULL) {
1783 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1784 __func__, poweroff_cmd);
1785 goto out;
1786 }
1787
1788 info = call_usermodehelper_setup(argv[0], argv, envp);
1789 if (info == NULL) {
1790 argv_free(argv);
1791 goto out;
1792 }
1793
1794 call_usermodehelper_setcleanup(info, argv_cleanup);
1795
1796 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1797
1798 out:
1799 if (ret && force) {
1800 printk(KERN_WARNING "Failed to start orderly shutdown: "
1801 "forcing the issue\n");
1802
1803 /* I guess this should try to kick off some daemon to
1804 sync and poweroff asap. Or not even bother syncing
1805 if we're doing an emergency shutdown? */
1806 emergency_sync();
1807 kernel_power_off();
1808 }
1809
1810 return ret;
1811 }
1812 EXPORT_SYMBOL_GPL(orderly_poweroff);
Support for the Chinese Samsung S3C2440 based development boards