notifiers: sys: move reboot notifiers into reboot.h
[linux-2.6.git] / kernel / sys.c
1 /*
2  *  linux/kernel/sys.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/perf_event.h>
16 #include <linux/resource.h>
17 #include <linux/kernel.h>
18 #include <linux/kexec.h>
19 #include <linux/workqueue.h>
20 #include <linux/capability.h>
21 #include <linux/device.h>
22 #include <linux/key.h>
23 #include <linux/times.h>
24 #include <linux/posix-timers.h>
25 #include <linux/security.h>
26 #include <linux/dcookies.h>
27 #include <linux/suspend.h>
28 #include <linux/tty.h>
29 #include <linux/signal.h>
30 #include <linux/cn_proc.h>
31 #include <linux/getcpu.h>
32 #include <linux/task_io_accounting_ops.h>
33 #include <linux/seccomp.h>
34 #include <linux/cpu.h>
35 #include <linux/personality.h>
36 #include <linux/ptrace.h>
37 #include <linux/fs_struct.h>
38 #include <linux/gfp.h>
39 #include <linux/syscore_ops.h>
40
41 #include <linux/compat.h>
42 #include <linux/syscalls.h>
43 #include <linux/kprobes.h>
44 #include <linux/user_namespace.h>
45
46 #include <linux/kmsg_dump.h>
47
48 #include <asm/uaccess.h>
49 #include <asm/io.h>
50 #include <asm/unistd.h>
51
52 #ifndef SET_UNALIGN_CTL
53 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
54 #endif
55 #ifndef GET_UNALIGN_CTL
56 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
57 #endif
58 #ifndef SET_FPEMU_CTL
59 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
60 #endif
61 #ifndef GET_FPEMU_CTL
62 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
63 #endif
64 #ifndef SET_FPEXC_CTL
65 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
66 #endif
67 #ifndef GET_FPEXC_CTL
68 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
69 #endif
70 #ifndef GET_ENDIAN
71 # define GET_ENDIAN(a,b)        (-EINVAL)
72 #endif
73 #ifndef SET_ENDIAN
74 # define SET_ENDIAN(a,b)        (-EINVAL)
75 #endif
76 #ifndef GET_TSC_CTL
77 # define GET_TSC_CTL(a)         (-EINVAL)
78 #endif
79 #ifndef SET_TSC_CTL
80 # define SET_TSC_CTL(a)         (-EINVAL)
81 #endif
82
83 /*
84  * this is where the system-wide overflow UID and GID are defined, for
85  * architectures that now have 32-bit UID/GID but didn't in the past
86  */
87
88 int overflowuid = DEFAULT_OVERFLOWUID;
89 int overflowgid = DEFAULT_OVERFLOWGID;
90
91 #ifdef CONFIG_UID16
92 EXPORT_SYMBOL(overflowuid);
93 EXPORT_SYMBOL(overflowgid);
94 #endif
95
96 /*
97  * the same as above, but for filesystems which can only store a 16-bit
98  * UID and GID. as such, this is needed on all architectures
99  */
100
101 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
102 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
103
104 EXPORT_SYMBOL(fs_overflowuid);
105 EXPORT_SYMBOL(fs_overflowgid);
106
107 /*
108  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
109  */
110
111 int C_A_D = 1;
112 struct pid *cad_pid;
113 EXPORT_SYMBOL(cad_pid);
114
115 /*
116  * If set, this is used for preparing the system to power off.
117  */
118
119 void (*pm_power_off_prepare)(void);
120
121 /*
122  * Returns true if current's euid is same as p's uid or euid,
123  * or has CAP_SYS_NICE to p's user_ns.
124  *
125  * Called with rcu_read_lock, creds are safe
126  */
127 static bool set_one_prio_perm(struct task_struct *p)
128 {
129         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
130
131         if (pcred->user->user_ns == cred->user->user_ns &&
132             (pcred->uid  == cred->euid ||
133              pcred->euid == cred->euid))
134                 return true;
135         if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
136                 return true;
137         return false;
138 }
139
140 /*
141  * set the priority of a task
142  * - the caller must hold the RCU read lock
143  */
144 static int set_one_prio(struct task_struct *p, int niceval, int error)
145 {
146         int no_nice;
147
148         if (!set_one_prio_perm(p)) {
149                 error = -EPERM;
150                 goto out;
151         }
152         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
153                 error = -EACCES;
154                 goto out;
155         }
156         no_nice = security_task_setnice(p, niceval);
157         if (no_nice) {
158                 error = no_nice;
159                 goto out;
160         }
161         if (error == -ESRCH)
162                 error = 0;
163         set_user_nice(p, niceval);
164 out:
165         return error;
166 }
167
168 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
169 {
170         struct task_struct *g, *p;
171         struct user_struct *user;
172         const struct cred *cred = current_cred();
173         int error = -EINVAL;
174         struct pid *pgrp;
175
176         if (which > PRIO_USER || which < PRIO_PROCESS)
177                 goto out;
178
179         /* normalize: avoid signed division (rounding problems) */
180         error = -ESRCH;
181         if (niceval < -20)
182                 niceval = -20;
183         if (niceval > 19)
184                 niceval = 19;
185
186         rcu_read_lock();
187         read_lock(&tasklist_lock);
188         switch (which) {
189                 case PRIO_PROCESS:
190                         if (who)
191                                 p = find_task_by_vpid(who);
192                         else
193                                 p = current;
194                         if (p)
195                                 error = set_one_prio(p, niceval, error);
196                         break;
197                 case PRIO_PGRP:
198                         if (who)
199                                 pgrp = find_vpid(who);
200                         else
201                                 pgrp = task_pgrp(current);
202                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
203                                 error = set_one_prio(p, niceval, error);
204                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
205                         break;
206                 case PRIO_USER:
207                         user = (struct user_struct *) cred->user;
208                         if (!who)
209                                 who = cred->uid;
210                         else if ((who != cred->uid) &&
211                                  !(user = find_user(who)))
212                                 goto out_unlock;        /* No processes for this user */
213
214                         do_each_thread(g, p) {
215                                 if (__task_cred(p)->uid == who)
216                                         error = set_one_prio(p, niceval, error);
217                         } while_each_thread(g, p);
218                         if (who != cred->uid)
219                                 free_uid(user);         /* For find_user() */
220                         break;
221         }
222 out_unlock:
223         read_unlock(&tasklist_lock);
224         rcu_read_unlock();
225 out:
226         return error;
227 }
228
229 /*
230  * Ugh. To avoid negative return values, "getpriority()" will
231  * not return the normal nice-value, but a negated value that
232  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
233  * to stay compatible.
234  */
235 SYSCALL_DEFINE2(getpriority, int, which, int, who)
236 {
237         struct task_struct *g, *p;
238         struct user_struct *user;
239         const struct cred *cred = current_cred();
240         long niceval, retval = -ESRCH;
241         struct pid *pgrp;
242
243         if (which > PRIO_USER || which < PRIO_PROCESS)
244                 return -EINVAL;
245
246         rcu_read_lock();
247         read_lock(&tasklist_lock);
248         switch (which) {
249                 case PRIO_PROCESS:
250                         if (who)
251                                 p = find_task_by_vpid(who);
252                         else
253                                 p = current;
254                         if (p) {
255                                 niceval = 20 - task_nice(p);
256                                 if (niceval > retval)
257                                         retval = niceval;
258                         }
259                         break;
260                 case PRIO_PGRP:
261                         if (who)
262                                 pgrp = find_vpid(who);
263                         else
264                                 pgrp = task_pgrp(current);
265                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
266                                 niceval = 20 - task_nice(p);
267                                 if (niceval > retval)
268                                         retval = niceval;
269                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
270                         break;
271                 case PRIO_USER:
272                         user = (struct user_struct *) cred->user;
273                         if (!who)
274                                 who = cred->uid;
275                         else if ((who != cred->uid) &&
276                                  !(user = find_user(who)))
277                                 goto out_unlock;        /* No processes for this user */
278
279                         do_each_thread(g, p) {
280                                 if (__task_cred(p)->uid == who) {
281                                         niceval = 20 - task_nice(p);
282                                         if (niceval > retval)
283                                                 retval = niceval;
284                                 }
285                         } while_each_thread(g, p);
286                         if (who != cred->uid)
287                                 free_uid(user);         /* for find_user() */
288                         break;
289         }
290 out_unlock:
291         read_unlock(&tasklist_lock);
292         rcu_read_unlock();
293
294         return retval;
295 }
296
297 /**
298  *      emergency_restart - reboot the system
299  *
300  *      Without shutting down any hardware or taking any locks
301  *      reboot the system.  This is called when we know we are in
302  *      trouble so this is our best effort to reboot.  This is
303  *      safe to call in interrupt context.
304  */
305 void emergency_restart(void)
306 {
307         kmsg_dump(KMSG_DUMP_EMERG);
308         machine_emergency_restart();
309 }
310 EXPORT_SYMBOL_GPL(emergency_restart);
311
312 void kernel_restart_prepare(char *cmd)
313 {
314         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
315         system_state = SYSTEM_RESTART;
316         usermodehelper_disable();
317         device_shutdown();
318         syscore_shutdown();
319 }
320
321 /**
322  *      register_reboot_notifier - Register function to be called at reboot time
323  *      @nb: Info about notifier function to be called
324  *
325  *      Registers a function with the list of functions
326  *      to be called at reboot time.
327  *
328  *      Currently always returns zero, as blocking_notifier_chain_register()
329  *      always returns zero.
330  */
331 int register_reboot_notifier(struct notifier_block *nb)
332 {
333         return blocking_notifier_chain_register(&reboot_notifier_list, nb);
334 }
335 EXPORT_SYMBOL(register_reboot_notifier);
336
337 /**
338  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
339  *      @nb: Hook to be unregistered
340  *
341  *      Unregisters a previously registered reboot
342  *      notifier function.
343  *
344  *      Returns zero on success, or %-ENOENT on failure.
345  */
346 int unregister_reboot_notifier(struct notifier_block *nb)
347 {
348         return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
349 }
350 EXPORT_SYMBOL(unregister_reboot_notifier);
351
352 /**
353  *      kernel_restart - reboot the system
354  *      @cmd: pointer to buffer containing command to execute for restart
355  *              or %NULL
356  *
357  *      Shutdown everything and perform a clean reboot.
358  *      This is not safe to call in interrupt context.
359  */
360 void kernel_restart(char *cmd)
361 {
362         kernel_restart_prepare(cmd);
363         if (!cmd)
364                 printk(KERN_EMERG "Restarting system.\n");
365         else
366                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
367         kmsg_dump(KMSG_DUMP_RESTART);
368         machine_restart(cmd);
369 }
370 EXPORT_SYMBOL_GPL(kernel_restart);
371
372 static void kernel_shutdown_prepare(enum system_states state)
373 {
374         blocking_notifier_call_chain(&reboot_notifier_list,
375                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
376         system_state = state;
377         usermodehelper_disable();
378         device_shutdown();
379 }
380 /**
381  *      kernel_halt - halt the system
382  *
383  *      Shutdown everything and perform a clean system halt.
384  */
385 void kernel_halt(void)
386 {
387         kernel_shutdown_prepare(SYSTEM_HALT);
388         syscore_shutdown();
389         printk(KERN_EMERG "System halted.\n");
390         kmsg_dump(KMSG_DUMP_HALT);
391         machine_halt();
392 }
393
394 EXPORT_SYMBOL_GPL(kernel_halt);
395
396 /**
397  *      kernel_power_off - power_off the system
398  *
399  *      Shutdown everything and perform a clean system power_off.
400  */
401 void kernel_power_off(void)
402 {
403         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
404         if (pm_power_off_prepare)
405                 pm_power_off_prepare();
406         disable_nonboot_cpus();
407         syscore_shutdown();
408         printk(KERN_EMERG "Power down.\n");
409         kmsg_dump(KMSG_DUMP_POWEROFF);
410         machine_power_off();
411 }
412 EXPORT_SYMBOL_GPL(kernel_power_off);
413
414 static DEFINE_MUTEX(reboot_mutex);
415
416 /*
417  * Reboot system call: for obvious reasons only root may call it,
418  * and even root needs to set up some magic numbers in the registers
419  * so that some mistake won't make this reboot the whole machine.
420  * You can also set the meaning of the ctrl-alt-del-key here.
421  *
422  * reboot doesn't sync: do that yourself before calling this.
423  */
424 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
425                 void __user *, arg)
426 {
427         char buffer[256];
428         int ret = 0;
429
430         /* We only trust the superuser with rebooting the system. */
431         if (!capable(CAP_SYS_BOOT))
432                 return -EPERM;
433
434         /* For safety, we require "magic" arguments. */
435         if (magic1 != LINUX_REBOOT_MAGIC1 ||
436             (magic2 != LINUX_REBOOT_MAGIC2 &&
437                         magic2 != LINUX_REBOOT_MAGIC2A &&
438                         magic2 != LINUX_REBOOT_MAGIC2B &&
439                         magic2 != LINUX_REBOOT_MAGIC2C))
440                 return -EINVAL;
441
442         /* Instead of trying to make the power_off code look like
443          * halt when pm_power_off is not set do it the easy way.
444          */
445         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
446                 cmd = LINUX_REBOOT_CMD_HALT;
447
448         mutex_lock(&reboot_mutex);
449         switch (cmd) {
450         case LINUX_REBOOT_CMD_RESTART:
451                 kernel_restart(NULL);
452                 break;
453
454         case LINUX_REBOOT_CMD_CAD_ON:
455                 C_A_D = 1;
456                 break;
457
458         case LINUX_REBOOT_CMD_CAD_OFF:
459                 C_A_D = 0;
460                 break;
461
462         case LINUX_REBOOT_CMD_HALT:
463                 kernel_halt();
464                 do_exit(0);
465                 panic("cannot halt");
466
467         case LINUX_REBOOT_CMD_POWER_OFF:
468                 kernel_power_off();
469                 do_exit(0);
470                 break;
471
472         case LINUX_REBOOT_CMD_RESTART2:
473                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
474                         ret = -EFAULT;
475                         break;
476                 }
477                 buffer[sizeof(buffer) - 1] = '\0';
478
479                 kernel_restart(buffer);
480                 break;
481
482 #ifdef CONFIG_KEXEC
483         case LINUX_REBOOT_CMD_KEXEC:
484                 ret = kernel_kexec();
485                 break;
486 #endif
487
488 #ifdef CONFIG_HIBERNATION
489         case LINUX_REBOOT_CMD_SW_SUSPEND:
490                 ret = hibernate();
491                 break;
492 #endif
493
494         default:
495                 ret = -EINVAL;
496                 break;
497         }
498         mutex_unlock(&reboot_mutex);
499         return ret;
500 }
501
502 static void deferred_cad(struct work_struct *dummy)
503 {
504         kernel_restart(NULL);
505 }
506
507 /*
508  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
509  * As it's called within an interrupt, it may NOT sync: the only choice
510  * is whether to reboot at once, or just ignore the ctrl-alt-del.
511  */
512 void ctrl_alt_del(void)
513 {
514         static DECLARE_WORK(cad_work, deferred_cad);
515
516         if (C_A_D)
517                 schedule_work(&cad_work);
518         else
519                 kill_cad_pid(SIGINT, 1);
520 }
521         
522 /*
523  * Unprivileged users may change the real gid to the effective gid
524  * or vice versa.  (BSD-style)
525  *
526  * If you set the real gid at all, or set the effective gid to a value not
527  * equal to the real gid, then the saved gid is set to the new effective gid.
528  *
529  * This makes it possible for a setgid program to completely drop its
530  * privileges, which is often a useful assertion to make when you are doing
531  * a security audit over a program.
532  *
533  * The general idea is that a program which uses just setregid() will be
534  * 100% compatible with BSD.  A program which uses just setgid() will be
535  * 100% compatible with POSIX with saved IDs. 
536  *
537  * SMP: There are not races, the GIDs are checked only by filesystem
538  *      operations (as far as semantic preservation is concerned).
539  */
540 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
541 {
542         const struct cred *old;
543         struct cred *new;
544         int retval;
545
546         new = prepare_creds();
547         if (!new)
548                 return -ENOMEM;
549         old = current_cred();
550
551         retval = -EPERM;
552         if (rgid != (gid_t) -1) {
553                 if (old->gid == rgid ||
554                     old->egid == rgid ||
555                     nsown_capable(CAP_SETGID))
556                         new->gid = rgid;
557                 else
558                         goto error;
559         }
560         if (egid != (gid_t) -1) {
561                 if (old->gid == egid ||
562                     old->egid == egid ||
563                     old->sgid == egid ||
564                     nsown_capable(CAP_SETGID))
565                         new->egid = egid;
566                 else
567                         goto error;
568         }
569
570         if (rgid != (gid_t) -1 ||
571             (egid != (gid_t) -1 && egid != old->gid))
572                 new->sgid = new->egid;
573         new->fsgid = new->egid;
574
575         return commit_creds(new);
576
577 error:
578         abort_creds(new);
579         return retval;
580 }
581
582 /*
583  * setgid() is implemented like SysV w/ SAVED_IDS 
584  *
585  * SMP: Same implicit races as above.
586  */
587 SYSCALL_DEFINE1(setgid, gid_t, gid)
588 {
589         const struct cred *old;
590         struct cred *new;
591         int retval;
592
593         new = prepare_creds();
594         if (!new)
595                 return -ENOMEM;
596         old = current_cred();
597
598         retval = -EPERM;
599         if (nsown_capable(CAP_SETGID))
600                 new->gid = new->egid = new->sgid = new->fsgid = gid;
601         else if (gid == old->gid || gid == old->sgid)
602                 new->egid = new->fsgid = gid;
603         else
604                 goto error;
605
606         return commit_creds(new);
607
608 error:
609         abort_creds(new);
610         return retval;
611 }
612
613 /*
614  * change the user struct in a credentials set to match the new UID
615  */
616 static int set_user(struct cred *new)
617 {
618         struct user_struct *new_user;
619
620         new_user = alloc_uid(current_user_ns(), new->uid);
621         if (!new_user)
622                 return -EAGAIN;
623
624         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
625                         new_user != INIT_USER) {
626                 free_uid(new_user);
627                 return -EAGAIN;
628         }
629
630         free_uid(new->user);
631         new->user = new_user;
632         return 0;
633 }
634
635 /*
636  * Unprivileged users may change the real uid to the effective uid
637  * or vice versa.  (BSD-style)
638  *
639  * If you set the real uid at all, or set the effective uid to a value not
640  * equal to the real uid, then the saved uid is set to the new effective uid.
641  *
642  * This makes it possible for a setuid program to completely drop its
643  * privileges, which is often a useful assertion to make when you are doing
644  * a security audit over a program.
645  *
646  * The general idea is that a program which uses just setreuid() will be
647  * 100% compatible with BSD.  A program which uses just setuid() will be
648  * 100% compatible with POSIX with saved IDs. 
649  */
650 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
651 {
652         const struct cred *old;
653         struct cred *new;
654         int retval;
655
656         new = prepare_creds();
657         if (!new)
658                 return -ENOMEM;
659         old = current_cred();
660
661         retval = -EPERM;
662         if (ruid != (uid_t) -1) {
663                 new->uid = ruid;
664                 if (old->uid != ruid &&
665                     old->euid != ruid &&
666                     !nsown_capable(CAP_SETUID))
667                         goto error;
668         }
669
670         if (euid != (uid_t) -1) {
671                 new->euid = euid;
672                 if (old->uid != euid &&
673                     old->euid != euid &&
674                     old->suid != euid &&
675                     !nsown_capable(CAP_SETUID))
676                         goto error;
677         }
678
679         if (new->uid != old->uid) {
680                 retval = set_user(new);
681                 if (retval < 0)
682                         goto error;
683         }
684         if (ruid != (uid_t) -1 ||
685             (euid != (uid_t) -1 && euid != old->uid))
686                 new->suid = new->euid;
687         new->fsuid = new->euid;
688
689         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
690         if (retval < 0)
691                 goto error;
692
693         return commit_creds(new);
694
695 error:
696         abort_creds(new);
697         return retval;
698 }
699                 
700 /*
701  * setuid() is implemented like SysV with SAVED_IDS 
702  * 
703  * Note that SAVED_ID's is deficient in that a setuid root program
704  * like sendmail, for example, cannot set its uid to be a normal 
705  * user and then switch back, because if you're root, setuid() sets
706  * the saved uid too.  If you don't like this, blame the bright people
707  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
708  * will allow a root program to temporarily drop privileges and be able to
709  * regain them by swapping the real and effective uid.  
710  */
711 SYSCALL_DEFINE1(setuid, uid_t, uid)
712 {
713         const struct cred *old;
714         struct cred *new;
715         int retval;
716
717         new = prepare_creds();
718         if (!new)
719                 return -ENOMEM;
720         old = current_cred();
721
722         retval = -EPERM;
723         if (nsown_capable(CAP_SETUID)) {
724                 new->suid = new->uid = uid;
725                 if (uid != old->uid) {
726                         retval = set_user(new);
727                         if (retval < 0)
728                                 goto error;
729                 }
730         } else if (uid != old->uid && uid != new->suid) {
731                 goto error;
732         }
733
734         new->fsuid = new->euid = uid;
735
736         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
737         if (retval < 0)
738                 goto error;
739
740         return commit_creds(new);
741
742 error:
743         abort_creds(new);
744         return retval;
745 }
746
747
748 /*
749  * This function implements a generic ability to update ruid, euid,
750  * and suid.  This allows you to implement the 4.4 compatible seteuid().
751  */
752 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
753 {
754         const struct cred *old;
755         struct cred *new;
756         int retval;
757
758         new = prepare_creds();
759         if (!new)
760                 return -ENOMEM;
761
762         old = current_cred();
763
764         retval = -EPERM;
765         if (!nsown_capable(CAP_SETUID)) {
766                 if (ruid != (uid_t) -1 && ruid != old->uid &&
767                     ruid != old->euid  && ruid != old->suid)
768                         goto error;
769                 if (euid != (uid_t) -1 && euid != old->uid &&
770                     euid != old->euid  && euid != old->suid)
771                         goto error;
772                 if (suid != (uid_t) -1 && suid != old->uid &&
773                     suid != old->euid  && suid != old->suid)
774                         goto error;
775         }
776
777         if (ruid != (uid_t) -1) {
778                 new->uid = ruid;
779                 if (ruid != old->uid) {
780                         retval = set_user(new);
781                         if (retval < 0)
782                                 goto error;
783                 }
784         }
785         if (euid != (uid_t) -1)
786                 new->euid = euid;
787         if (suid != (uid_t) -1)
788                 new->suid = suid;
789         new->fsuid = new->euid;
790
791         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
792         if (retval < 0)
793                 goto error;
794
795         return commit_creds(new);
796
797 error:
798         abort_creds(new);
799         return retval;
800 }
801
802 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
803 {
804         const struct cred *cred = current_cred();
805         int retval;
806
807         if (!(retval   = put_user(cred->uid,  ruid)) &&
808             !(retval   = put_user(cred->euid, euid)))
809                 retval = put_user(cred->suid, suid);
810
811         return retval;
812 }
813
814 /*
815  * Same as above, but for rgid, egid, sgid.
816  */
817 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
818 {
819         const struct cred *old;
820         struct cred *new;
821         int retval;
822
823         new = prepare_creds();
824         if (!new)
825                 return -ENOMEM;
826         old = current_cred();
827
828         retval = -EPERM;
829         if (!nsown_capable(CAP_SETGID)) {
830                 if (rgid != (gid_t) -1 && rgid != old->gid &&
831                     rgid != old->egid  && rgid != old->sgid)
832                         goto error;
833                 if (egid != (gid_t) -1 && egid != old->gid &&
834                     egid != old->egid  && egid != old->sgid)
835                         goto error;
836                 if (sgid != (gid_t) -1 && sgid != old->gid &&
837                     sgid != old->egid  && sgid != old->sgid)
838                         goto error;
839         }
840
841         if (rgid != (gid_t) -1)
842                 new->gid = rgid;
843         if (egid != (gid_t) -1)
844                 new->egid = egid;
845         if (sgid != (gid_t) -1)
846                 new->sgid = sgid;
847         new->fsgid = new->egid;
848
849         return commit_creds(new);
850
851 error:
852         abort_creds(new);
853         return retval;
854 }
855
856 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
857 {
858         const struct cred *cred = current_cred();
859         int retval;
860
861         if (!(retval   = put_user(cred->gid,  rgid)) &&
862             !(retval   = put_user(cred->egid, egid)))
863                 retval = put_user(cred->sgid, sgid);
864
865         return retval;
866 }
867
868
869 /*
870  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
871  * is used for "access()" and for the NFS daemon (letting nfsd stay at
872  * whatever uid it wants to). It normally shadows "euid", except when
873  * explicitly set by setfsuid() or for access..
874  */
875 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
876 {
877         const struct cred *old;
878         struct cred *new;
879         uid_t old_fsuid;
880
881         new = prepare_creds();
882         if (!new)
883                 return current_fsuid();
884         old = current_cred();
885         old_fsuid = old->fsuid;
886
887         if (uid == old->uid  || uid == old->euid  ||
888             uid == old->suid || uid == old->fsuid ||
889             nsown_capable(CAP_SETUID)) {
890                 if (uid != old_fsuid) {
891                         new->fsuid = uid;
892                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
893                                 goto change_okay;
894                 }
895         }
896
897         abort_creds(new);
898         return old_fsuid;
899
900 change_okay:
901         commit_creds(new);
902         return old_fsuid;
903 }
904
905 /*
906  * Samma på svenska..
907  */
908 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
909 {
910         const struct cred *old;
911         struct cred *new;
912         gid_t old_fsgid;
913
914         new = prepare_creds();
915         if (!new)
916                 return current_fsgid();
917         old = current_cred();
918         old_fsgid = old->fsgid;
919
920         if (gid == old->gid  || gid == old->egid  ||
921             gid == old->sgid || gid == old->fsgid ||
922             nsown_capable(CAP_SETGID)) {
923                 if (gid != old_fsgid) {
924                         new->fsgid = gid;
925                         goto change_okay;
926                 }
927         }
928
929         abort_creds(new);
930         return old_fsgid;
931
932 change_okay:
933         commit_creds(new);
934         return old_fsgid;
935 }
936
937 void do_sys_times(struct tms *tms)
938 {
939         cputime_t tgutime, tgstime, cutime, cstime;
940
941         spin_lock_irq(&current->sighand->siglock);
942         thread_group_times(current, &tgutime, &tgstime);
943         cutime = current->signal->cutime;
944         cstime = current->signal->cstime;
945         spin_unlock_irq(&current->sighand->siglock);
946         tms->tms_utime = cputime_to_clock_t(tgutime);
947         tms->tms_stime = cputime_to_clock_t(tgstime);
948         tms->tms_cutime = cputime_to_clock_t(cutime);
949         tms->tms_cstime = cputime_to_clock_t(cstime);
950 }
951
952 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
953 {
954         if (tbuf) {
955                 struct tms tmp;
956
957                 do_sys_times(&tmp);
958                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
959                         return -EFAULT;
960         }
961         force_successful_syscall_return();
962         return (long) jiffies_64_to_clock_t(get_jiffies_64());
963 }
964
965 /*
966  * This needs some heavy checking ...
967  * I just haven't the stomach for it. I also don't fully
968  * understand sessions/pgrp etc. Let somebody who does explain it.
969  *
970  * OK, I think I have the protection semantics right.... this is really
971  * only important on a multi-user system anyway, to make sure one user
972  * can't send a signal to a process owned by another.  -TYT, 12/12/91
973  *
974  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
975  * LBT 04.03.94
976  */
977 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
978 {
979         struct task_struct *p;
980         struct task_struct *group_leader = current->group_leader;
981         struct pid *pgrp;
982         int err;
983
984         if (!pid)
985                 pid = task_pid_vnr(group_leader);
986         if (!pgid)
987                 pgid = pid;
988         if (pgid < 0)
989                 return -EINVAL;
990         rcu_read_lock();
991
992         /* From this point forward we keep holding onto the tasklist lock
993          * so that our parent does not change from under us. -DaveM
994          */
995         write_lock_irq(&tasklist_lock);
996
997         err = -ESRCH;
998         p = find_task_by_vpid(pid);
999         if (!p)
1000                 goto out;
1001
1002         err = -EINVAL;
1003         if (!thread_group_leader(p))
1004                 goto out;
1005
1006         if (same_thread_group(p->real_parent, group_leader)) {
1007                 err = -EPERM;
1008                 if (task_session(p) != task_session(group_leader))
1009                         goto out;
1010                 err = -EACCES;
1011                 if (p->did_exec)
1012                         goto out;
1013         } else {
1014                 err = -ESRCH;
1015                 if (p != group_leader)
1016                         goto out;
1017         }
1018
1019         err = -EPERM;
1020         if (p->signal->leader)
1021                 goto out;
1022
1023         pgrp = task_pid(p);
1024         if (pgid != pid) {
1025                 struct task_struct *g;
1026
1027                 pgrp = find_vpid(pgid);
1028                 g = pid_task(pgrp, PIDTYPE_PGID);
1029                 if (!g || task_session(g) != task_session(group_leader))
1030                         goto out;
1031         }
1032
1033         err = security_task_setpgid(p, pgid);
1034         if (err)
1035                 goto out;
1036
1037         if (task_pgrp(p) != pgrp)
1038                 change_pid(p, PIDTYPE_PGID, pgrp);
1039
1040         err = 0;
1041 out:
1042         /* All paths lead to here, thus we are safe. -DaveM */
1043         write_unlock_irq(&tasklist_lock);
1044         rcu_read_unlock();
1045         return err;
1046 }
1047
1048 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1049 {
1050         struct task_struct *p;
1051         struct pid *grp;
1052         int retval;
1053
1054         rcu_read_lock();
1055         if (!pid)
1056                 grp = task_pgrp(current);
1057         else {
1058                 retval = -ESRCH;
1059                 p = find_task_by_vpid(pid);
1060                 if (!p)
1061                         goto out;
1062                 grp = task_pgrp(p);
1063                 if (!grp)
1064                         goto out;
1065
1066                 retval = security_task_getpgid(p);
1067                 if (retval)
1068                         goto out;
1069         }
1070         retval = pid_vnr(grp);
1071 out:
1072         rcu_read_unlock();
1073         return retval;
1074 }
1075
1076 #ifdef __ARCH_WANT_SYS_GETPGRP
1077
1078 SYSCALL_DEFINE0(getpgrp)
1079 {
1080         return sys_getpgid(0);
1081 }
1082
1083 #endif
1084
1085 SYSCALL_DEFINE1(getsid, pid_t, pid)
1086 {
1087         struct task_struct *p;
1088         struct pid *sid;
1089         int retval;
1090
1091         rcu_read_lock();
1092         if (!pid)
1093                 sid = task_session(current);
1094         else {
1095                 retval = -ESRCH;
1096                 p = find_task_by_vpid(pid);
1097                 if (!p)
1098                         goto out;
1099                 sid = task_session(p);
1100                 if (!sid)
1101                         goto out;
1102
1103                 retval = security_task_getsid(p);
1104                 if (retval)
1105                         goto out;
1106         }
1107         retval = pid_vnr(sid);
1108 out:
1109         rcu_read_unlock();
1110         return retval;
1111 }
1112
1113 SYSCALL_DEFINE0(setsid)
1114 {
1115         struct task_struct *group_leader = current->group_leader;
1116         struct pid *sid = task_pid(group_leader);
1117         pid_t session = pid_vnr(sid);
1118         int err = -EPERM;
1119
1120         write_lock_irq(&tasklist_lock);
1121         /* Fail if I am already a session leader */
1122         if (group_leader->signal->leader)
1123                 goto out;
1124
1125         /* Fail if a process group id already exists that equals the
1126          * proposed session id.
1127          */
1128         if (pid_task(sid, PIDTYPE_PGID))
1129                 goto out;
1130
1131         group_leader->signal->leader = 1;
1132         __set_special_pids(sid);
1133
1134         proc_clear_tty(group_leader);
1135
1136         err = session;
1137 out:
1138         write_unlock_irq(&tasklist_lock);
1139         if (err > 0) {
1140                 proc_sid_connector(group_leader);
1141                 sched_autogroup_create_attach(group_leader);
1142         }
1143         return err;
1144 }
1145
1146 DECLARE_RWSEM(uts_sem);
1147
1148 #ifdef COMPAT_UTS_MACHINE
1149 #define override_architecture(name) \
1150         (personality(current->personality) == PER_LINUX32 && \
1151          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1152                       sizeof(COMPAT_UTS_MACHINE)))
1153 #else
1154 #define override_architecture(name)     0
1155 #endif
1156
1157 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1158 {
1159         int errno = 0;
1160
1161         down_read(&uts_sem);
1162         if (copy_to_user(name, utsname(), sizeof *name))
1163                 errno = -EFAULT;
1164         up_read(&uts_sem);
1165
1166         if (!errno && override_architecture(name))
1167                 errno = -EFAULT;
1168         return errno;
1169 }
1170
1171 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1172 /*
1173  * Old cruft
1174  */
1175 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1176 {
1177         int error = 0;
1178
1179         if (!name)
1180                 return -EFAULT;
1181
1182         down_read(&uts_sem);
1183         if (copy_to_user(name, utsname(), sizeof(*name)))
1184                 error = -EFAULT;
1185         up_read(&uts_sem);
1186
1187         if (!error && override_architecture(name))
1188                 error = -EFAULT;
1189         return error;
1190 }
1191
1192 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1193 {
1194         int error;
1195
1196         if (!name)
1197                 return -EFAULT;
1198         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1199                 return -EFAULT;
1200
1201         down_read(&uts_sem);
1202         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1203                                __OLD_UTS_LEN);
1204         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1205         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1206                                 __OLD_UTS_LEN);
1207         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1208         error |= __copy_to_user(&name->release, &utsname()->release,
1209                                 __OLD_UTS_LEN);
1210         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1211         error |= __copy_to_user(&name->version, &utsname()->version,
1212                                 __OLD_UTS_LEN);
1213         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1214         error |= __copy_to_user(&name->machine, &utsname()->machine,
1215                                 __OLD_UTS_LEN);
1216         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1217         up_read(&uts_sem);
1218
1219         if (!error && override_architecture(name))
1220                 error = -EFAULT;
1221         return error ? -EFAULT : 0;
1222 }
1223 #endif
1224
1225 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1226 {
1227         int errno;
1228         char tmp[__NEW_UTS_LEN];
1229
1230         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1231                 return -EPERM;
1232
1233         if (len < 0 || len > __NEW_UTS_LEN)
1234                 return -EINVAL;
1235         down_write(&uts_sem);
1236         errno = -EFAULT;
1237         if (!copy_from_user(tmp, name, len)) {
1238                 struct new_utsname *u = utsname();
1239
1240                 memcpy(u->nodename, tmp, len);
1241                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1242                 errno = 0;
1243         }
1244         up_write(&uts_sem);
1245         return errno;
1246 }
1247
1248 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1249
1250 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1251 {
1252         int i, errno;
1253         struct new_utsname *u;
1254
1255         if (len < 0)
1256                 return -EINVAL;
1257         down_read(&uts_sem);
1258         u = utsname();
1259         i = 1 + strlen(u->nodename);
1260         if (i > len)
1261                 i = len;
1262         errno = 0;
1263         if (copy_to_user(name, u->nodename, i))
1264                 errno = -EFAULT;
1265         up_read(&uts_sem);
1266         return errno;
1267 }
1268
1269 #endif
1270
1271 /*
1272  * Only setdomainname; getdomainname can be implemented by calling
1273  * uname()
1274  */
1275 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1276 {
1277         int errno;
1278         char tmp[__NEW_UTS_LEN];
1279
1280         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1281                 return -EPERM;
1282         if (len < 0 || len > __NEW_UTS_LEN)
1283                 return -EINVAL;
1284
1285         down_write(&uts_sem);
1286         errno = -EFAULT;
1287         if (!copy_from_user(tmp, name, len)) {
1288                 struct new_utsname *u = utsname();
1289
1290                 memcpy(u->domainname, tmp, len);
1291                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1292                 errno = 0;
1293         }
1294         up_write(&uts_sem);
1295         return errno;
1296 }
1297
1298 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1299 {
1300         struct rlimit value;
1301         int ret;
1302
1303         ret = do_prlimit(current, resource, NULL, &value);
1304         if (!ret)
1305                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1306
1307         return ret;
1308 }
1309
1310 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1311
1312 /*
1313  *      Back compatibility for getrlimit. Needed for some apps.
1314  */
1315  
1316 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1317                 struct rlimit __user *, rlim)
1318 {
1319         struct rlimit x;
1320         if (resource >= RLIM_NLIMITS)
1321                 return -EINVAL;
1322
1323         task_lock(current->group_leader);
1324         x = current->signal->rlim[resource];
1325         task_unlock(current->group_leader);
1326         if (x.rlim_cur > 0x7FFFFFFF)
1327                 x.rlim_cur = 0x7FFFFFFF;
1328         if (x.rlim_max > 0x7FFFFFFF)
1329                 x.rlim_max = 0x7FFFFFFF;
1330         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1331 }
1332
1333 #endif
1334
1335 static inline bool rlim64_is_infinity(__u64 rlim64)
1336 {
1337 #if BITS_PER_LONG < 64
1338         return rlim64 >= ULONG_MAX;
1339 #else
1340         return rlim64 == RLIM64_INFINITY;
1341 #endif
1342 }
1343
1344 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1345 {
1346         if (rlim->rlim_cur == RLIM_INFINITY)
1347                 rlim64->rlim_cur = RLIM64_INFINITY;
1348         else
1349                 rlim64->rlim_cur = rlim->rlim_cur;
1350         if (rlim->rlim_max == RLIM_INFINITY)
1351                 rlim64->rlim_max = RLIM64_INFINITY;
1352         else
1353                 rlim64->rlim_max = rlim->rlim_max;
1354 }
1355
1356 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1357 {
1358         if (rlim64_is_infinity(rlim64->rlim_cur))
1359                 rlim->rlim_cur = RLIM_INFINITY;
1360         else
1361                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1362         if (rlim64_is_infinity(rlim64->rlim_max))
1363                 rlim->rlim_max = RLIM_INFINITY;
1364         else
1365                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1366 }
1367
1368 /* make sure you are allowed to change @tsk limits before calling this */
1369 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1370                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1371 {
1372         struct rlimit *rlim;
1373         int retval = 0;
1374
1375         if (resource >= RLIM_NLIMITS)
1376                 return -EINVAL;
1377         if (new_rlim) {
1378                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1379                         return -EINVAL;
1380                 if (resource == RLIMIT_NOFILE &&
1381                                 new_rlim->rlim_max > sysctl_nr_open)
1382                         return -EPERM;
1383         }
1384
1385         /* protect tsk->signal and tsk->sighand from disappearing */
1386         read_lock(&tasklist_lock);
1387         if (!tsk->sighand) {
1388                 retval = -ESRCH;
1389                 goto out;
1390         }
1391
1392         rlim = tsk->signal->rlim + resource;
1393         task_lock(tsk->group_leader);
1394         if (new_rlim) {
1395                 /* Keep the capable check against init_user_ns until
1396                    cgroups can contain all limits */
1397                 if (new_rlim->rlim_max > rlim->rlim_max &&
1398                                 !capable(CAP_SYS_RESOURCE))
1399                         retval = -EPERM;
1400                 if (!retval)
1401                         retval = security_task_setrlimit(tsk->group_leader,
1402                                         resource, new_rlim);
1403                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1404                         /*
1405                          * The caller is asking for an immediate RLIMIT_CPU
1406                          * expiry.  But we use the zero value to mean "it was
1407                          * never set".  So let's cheat and make it one second
1408                          * instead
1409                          */
1410                         new_rlim->rlim_cur = 1;
1411                 }
1412         }
1413         if (!retval) {
1414                 if (old_rlim)
1415                         *old_rlim = *rlim;
1416                 if (new_rlim)
1417                         *rlim = *new_rlim;
1418         }
1419         task_unlock(tsk->group_leader);
1420
1421         /*
1422          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1423          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1424          * very long-standing error, and fixing it now risks breakage of
1425          * applications, so we live with it
1426          */
1427          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1428                          new_rlim->rlim_cur != RLIM_INFINITY)
1429                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1430 out:
1431         read_unlock(&tasklist_lock);
1432         return retval;
1433 }
1434
1435 /* rcu lock must be held */
1436 static int check_prlimit_permission(struct task_struct *task)
1437 {
1438         const struct cred *cred = current_cred(), *tcred;
1439
1440         if (current == task)
1441                 return 0;
1442
1443         tcred = __task_cred(task);
1444         if (cred->user->user_ns == tcred->user->user_ns &&
1445             (cred->uid == tcred->euid &&
1446              cred->uid == tcred->suid &&
1447              cred->uid == tcred->uid  &&
1448              cred->gid == tcred->egid &&
1449              cred->gid == tcred->sgid &&
1450              cred->gid == tcred->gid))
1451                 return 0;
1452         if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1453                 return 0;
1454
1455         return -EPERM;
1456 }
1457
1458 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1459                 const struct rlimit64 __user *, new_rlim,
1460                 struct rlimit64 __user *, old_rlim)
1461 {
1462         struct rlimit64 old64, new64;
1463         struct rlimit old, new;
1464         struct task_struct *tsk;
1465         int ret;
1466
1467         if (new_rlim) {
1468                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1469                         return -EFAULT;
1470                 rlim64_to_rlim(&new64, &new);
1471         }
1472
1473         rcu_read_lock();
1474         tsk = pid ? find_task_by_vpid(pid) : current;
1475         if (!tsk) {
1476                 rcu_read_unlock();
1477                 return -ESRCH;
1478         }
1479         ret = check_prlimit_permission(tsk);
1480         if (ret) {
1481                 rcu_read_unlock();
1482                 return ret;
1483         }
1484         get_task_struct(tsk);
1485         rcu_read_unlock();
1486
1487         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1488                         old_rlim ? &old : NULL);
1489
1490         if (!ret && old_rlim) {
1491                 rlim_to_rlim64(&old, &old64);
1492                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1493                         ret = -EFAULT;
1494         }
1495
1496         put_task_struct(tsk);
1497         return ret;
1498 }
1499
1500 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1501 {
1502         struct rlimit new_rlim;
1503
1504         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1505                 return -EFAULT;
1506         return do_prlimit(current, resource, &new_rlim, NULL);
1507 }
1508
1509 /*
1510  * It would make sense to put struct rusage in the task_struct,
1511  * except that would make the task_struct be *really big*.  After
1512  * task_struct gets moved into malloc'ed memory, it would
1513  * make sense to do this.  It will make moving the rest of the information
1514  * a lot simpler!  (Which we're not doing right now because we're not
1515  * measuring them yet).
1516  *
1517  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1518  * races with threads incrementing their own counters.  But since word
1519  * reads are atomic, we either get new values or old values and we don't
1520  * care which for the sums.  We always take the siglock to protect reading
1521  * the c* fields from p->signal from races with exit.c updating those
1522  * fields when reaping, so a sample either gets all the additions of a
1523  * given child after it's reaped, or none so this sample is before reaping.
1524  *
1525  * Locking:
1526  * We need to take the siglock for CHILDEREN, SELF and BOTH
1527  * for  the cases current multithreaded, non-current single threaded
1528  * non-current multithreaded.  Thread traversal is now safe with
1529  * the siglock held.
1530  * Strictly speaking, we donot need to take the siglock if we are current and
1531  * single threaded,  as no one else can take our signal_struct away, no one
1532  * else can  reap the  children to update signal->c* counters, and no one else
1533  * can race with the signal-> fields. If we do not take any lock, the
1534  * signal-> fields could be read out of order while another thread was just
1535  * exiting. So we should  place a read memory barrier when we avoid the lock.
1536  * On the writer side,  write memory barrier is implied in  __exit_signal
1537  * as __exit_signal releases  the siglock spinlock after updating the signal->
1538  * fields. But we don't do this yet to keep things simple.
1539  *
1540  */
1541
1542 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1543 {
1544         r->ru_nvcsw += t->nvcsw;
1545         r->ru_nivcsw += t->nivcsw;
1546         r->ru_minflt += t->min_flt;
1547         r->ru_majflt += t->maj_flt;
1548         r->ru_inblock += task_io_get_inblock(t);
1549         r->ru_oublock += task_io_get_oublock(t);
1550 }
1551
1552 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1553 {
1554         struct task_struct *t;
1555         unsigned long flags;
1556         cputime_t tgutime, tgstime, utime, stime;
1557         unsigned long maxrss = 0;
1558
1559         memset((char *) r, 0, sizeof *r);
1560         utime = stime = cputime_zero;
1561
1562         if (who == RUSAGE_THREAD) {
1563                 task_times(current, &utime, &stime);
1564                 accumulate_thread_rusage(p, r);
1565                 maxrss = p->signal->maxrss;
1566                 goto out;
1567         }
1568
1569         if (!lock_task_sighand(p, &flags))
1570                 return;
1571
1572         switch (who) {
1573                 case RUSAGE_BOTH:
1574                 case RUSAGE_CHILDREN:
1575                         utime = p->signal->cutime;
1576                         stime = p->signal->cstime;
1577                         r->ru_nvcsw = p->signal->cnvcsw;
1578                         r->ru_nivcsw = p->signal->cnivcsw;
1579                         r->ru_minflt = p->signal->cmin_flt;
1580                         r->ru_majflt = p->signal->cmaj_flt;
1581                         r->ru_inblock = p->signal->cinblock;
1582                         r->ru_oublock = p->signal->coublock;
1583                         maxrss = p->signal->cmaxrss;
1584
1585                         if (who == RUSAGE_CHILDREN)
1586                                 break;
1587
1588                 case RUSAGE_SELF:
1589                         thread_group_times(p, &tgutime, &tgstime);
1590                         utime = cputime_add(utime, tgutime);
1591                         stime = cputime_add(stime, tgstime);
1592                         r->ru_nvcsw += p->signal->nvcsw;
1593                         r->ru_nivcsw += p->signal->nivcsw;
1594                         r->ru_minflt += p->signal->min_flt;
1595                         r->ru_majflt += p->signal->maj_flt;
1596                         r->ru_inblock += p->signal->inblock;
1597                         r->ru_oublock += p->signal->oublock;
1598                         if (maxrss < p->signal->maxrss)
1599                                 maxrss = p->signal->maxrss;
1600                         t = p;
1601                         do {
1602                                 accumulate_thread_rusage(t, r);
1603                                 t = next_thread(t);
1604                         } while (t != p);
1605                         break;
1606
1607                 default:
1608                         BUG();
1609         }
1610         unlock_task_sighand(p, &flags);
1611
1612 out:
1613         cputime_to_timeval(utime, &r->ru_utime);
1614         cputime_to_timeval(stime, &r->ru_stime);
1615
1616         if (who != RUSAGE_CHILDREN) {
1617                 struct mm_struct *mm = get_task_mm(p);
1618                 if (mm) {
1619                         setmax_mm_hiwater_rss(&maxrss, mm);
1620                         mmput(mm);
1621                 }
1622         }
1623         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1624 }
1625
1626 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1627 {
1628         struct rusage r;
1629         k_getrusage(p, who, &r);
1630         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1631 }
1632
1633 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1634 {
1635         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1636             who != RUSAGE_THREAD)
1637                 return -EINVAL;
1638         return getrusage(current, who, ru);
1639 }
1640
1641 SYSCALL_DEFINE1(umask, int, mask)
1642 {
1643         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1644         return mask;
1645 }
1646
1647 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1648                 unsigned long, arg4, unsigned long, arg5)
1649 {
1650         struct task_struct *me = current;
1651         unsigned char comm[sizeof(me->comm)];
1652         long error;
1653
1654         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1655         if (error != -ENOSYS)
1656                 return error;
1657
1658         error = 0;
1659         switch (option) {
1660                 case PR_SET_PDEATHSIG:
1661                         if (!valid_signal(arg2)) {
1662                                 error = -EINVAL;
1663                                 break;
1664                         }
1665                         me->pdeath_signal = arg2;
1666                         error = 0;
1667                         break;
1668                 case PR_GET_PDEATHSIG:
1669                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1670                         break;
1671                 case PR_GET_DUMPABLE:
1672                         error = get_dumpable(me->mm);
1673                         break;
1674                 case PR_SET_DUMPABLE:
1675                         if (arg2 < 0 || arg2 > 1) {
1676                                 error = -EINVAL;
1677                                 break;
1678                         }
1679                         set_dumpable(me->mm, arg2);
1680                         error = 0;
1681                         break;
1682
1683                 case PR_SET_UNALIGN:
1684                         error = SET_UNALIGN_CTL(me, arg2);
1685                         break;
1686                 case PR_GET_UNALIGN:
1687                         error = GET_UNALIGN_CTL(me, arg2);
1688                         break;
1689                 case PR_SET_FPEMU:
1690                         error = SET_FPEMU_CTL(me, arg2);
1691                         break;
1692                 case PR_GET_FPEMU:
1693                         error = GET_FPEMU_CTL(me, arg2);
1694                         break;
1695                 case PR_SET_FPEXC:
1696                         error = SET_FPEXC_CTL(me, arg2);
1697                         break;
1698                 case PR_GET_FPEXC:
1699                         error = GET_FPEXC_CTL(me, arg2);
1700                         break;
1701                 case PR_GET_TIMING:
1702                         error = PR_TIMING_STATISTICAL;
1703                         break;
1704                 case PR_SET_TIMING:
1705                         if (arg2 != PR_TIMING_STATISTICAL)
1706                                 error = -EINVAL;
1707                         else
1708                                 error = 0;
1709                         break;
1710
1711                 case PR_SET_NAME:
1712                         comm[sizeof(me->comm)-1] = 0;
1713                         if (strncpy_from_user(comm, (char __user *)arg2,
1714                                               sizeof(me->comm) - 1) < 0)
1715                                 return -EFAULT;
1716                         set_task_comm(me, comm);
1717                         return 0;
1718                 case PR_GET_NAME:
1719                         get_task_comm(comm, me);
1720                         if (copy_to_user((char __user *)arg2, comm,
1721                                          sizeof(comm)))
1722                                 return -EFAULT;
1723                         return 0;
1724                 case PR_GET_ENDIAN:
1725                         error = GET_ENDIAN(me, arg2);
1726                         break;
1727                 case PR_SET_ENDIAN:
1728                         error = SET_ENDIAN(me, arg2);
1729                         break;
1730
1731                 case PR_GET_SECCOMP:
1732                         error = prctl_get_seccomp();
1733                         break;
1734                 case PR_SET_SECCOMP:
1735                         error = prctl_set_seccomp(arg2);
1736                         break;
1737                 case PR_GET_TSC:
1738                         error = GET_TSC_CTL(arg2);
1739                         break;
1740                 case PR_SET_TSC:
1741                         error = SET_TSC_CTL(arg2);
1742                         break;
1743                 case PR_TASK_PERF_EVENTS_DISABLE:
1744                         error = perf_event_task_disable();
1745                         break;
1746                 case PR_TASK_PERF_EVENTS_ENABLE:
1747                         error = perf_event_task_enable();
1748                         break;
1749                 case PR_GET_TIMERSLACK:
1750                         error = current->timer_slack_ns;
1751                         break;
1752                 case PR_SET_TIMERSLACK:
1753                         if (arg2 <= 0)
1754                                 current->timer_slack_ns =
1755                                         current->default_timer_slack_ns;
1756                         else
1757                                 current->timer_slack_ns = arg2;
1758                         error = 0;
1759                         break;
1760                 case PR_MCE_KILL:
1761                         if (arg4 | arg5)
1762                                 return -EINVAL;
1763                         switch (arg2) {
1764                         case PR_MCE_KILL_CLEAR:
1765                                 if (arg3 != 0)
1766                                         return -EINVAL;
1767                                 current->flags &= ~PF_MCE_PROCESS;
1768                                 break;
1769                         case PR_MCE_KILL_SET:
1770                                 current->flags |= PF_MCE_PROCESS;
1771                                 if (arg3 == PR_MCE_KILL_EARLY)
1772                                         current->flags |= PF_MCE_EARLY;
1773                                 else if (arg3 == PR_MCE_KILL_LATE)
1774                                         current->flags &= ~PF_MCE_EARLY;
1775                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1776                                         current->flags &=
1777                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1778                                 else
1779                                         return -EINVAL;
1780                                 break;
1781                         default:
1782                                 return -EINVAL;
1783                         }
1784                         error = 0;
1785                         break;
1786                 case PR_MCE_KILL_GET:
1787                         if (arg2 | arg3 | arg4 | arg5)
1788                                 return -EINVAL;
1789                         if (current->flags & PF_MCE_PROCESS)
1790                                 error = (current->flags & PF_MCE_EARLY) ?
1791                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1792                         else
1793                                 error = PR_MCE_KILL_DEFAULT;
1794                         break;
1795                 default:
1796                         error = -EINVAL;
1797                         break;
1798         }
1799         return error;
1800 }
1801
1802 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1803                 struct getcpu_cache __user *, unused)
1804 {
1805         int err = 0;
1806         int cpu = raw_smp_processor_id();
1807         if (cpup)
1808                 err |= put_user(cpu, cpup);
1809         if (nodep)
1810                 err |= put_user(cpu_to_node(cpu), nodep);
1811         return err ? -EFAULT : 0;
1812 }
1813
1814 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1815
1816 static void argv_cleanup(struct subprocess_info *info)
1817 {
1818         argv_free(info->argv);
1819 }
1820
1821 /**
1822  * orderly_poweroff - Trigger an orderly system poweroff
1823  * @force: force poweroff if command execution fails
1824  *
1825  * This may be called from any context to trigger a system shutdown.
1826  * If the orderly shutdown fails, it will force an immediate shutdown.
1827  */
1828 int orderly_poweroff(bool force)
1829 {
1830         int argc;
1831         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1832         static char *envp[] = {
1833                 "HOME=/",
1834                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1835                 NULL
1836         };
1837         int ret = -ENOMEM;
1838         struct subprocess_info *info;
1839
1840         if (argv == NULL) {
1841                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1842                        __func__, poweroff_cmd);
1843                 goto out;
1844         }
1845
1846         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1847         if (info == NULL) {
1848                 argv_free(argv);
1849                 goto out;
1850         }
1851
1852         call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1853
1854         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1855
1856   out:
1857         if (ret && force) {
1858                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1859                        "forcing the issue\n");
1860
1861                 /* I guess this should try to kick off some daemon to
1862                    sync and poweroff asap.  Or not even bother syncing
1863                    if we're doing an emergency shutdown? */
1864                 emergency_sync();
1865                 kernel_power_off();
1866         }
1867
1868         return ret;
1869 }
1870 EXPORT_SYMBOL_GPL(orderly_poweroff);