rtc: tps6591x: wake up from suspend on alarm
[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/export.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/kmod.h>
16 #include <linux/perf_event.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 #include <linux/personality.h>
37 #include <linux/ptrace.h>
38 #include <linux/fs_struct.h>
39 #include <linux/gfp.h>
40 #include <linux/syscore_ops.h>
41 #include <linux/version.h>
42 #include <linux/ctype.h>
43
44 #include <linux/compat.h>
45 #include <linux/syscalls.h>
46 #include <linux/kprobes.h>
47 #include <linux/user_namespace.h>
48
49 #include <linux/kmsg_dump.h>
50 /* Move somewhere else to avoid recompiling? */
51 #include <generated/utsrelease.h>
52
53 #include <asm/uaccess.h>
54 #include <asm/io.h>
55 #include <asm/unistd.h>
56
57 #ifndef SET_UNALIGN_CTL
58 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
59 #endif
60 #ifndef GET_UNALIGN_CTL
61 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
62 #endif
63 #ifndef SET_FPEMU_CTL
64 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
65 #endif
66 #ifndef GET_FPEMU_CTL
67 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
68 #endif
69 #ifndef SET_FPEXC_CTL
70 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
71 #endif
72 #ifndef GET_FPEXC_CTL
73 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
74 #endif
75 #ifndef GET_ENDIAN
76 # define GET_ENDIAN(a,b)        (-EINVAL)
77 #endif
78 #ifndef SET_ENDIAN
79 # define SET_ENDIAN(a,b)        (-EINVAL)
80 #endif
81 #ifndef GET_TSC_CTL
82 # define GET_TSC_CTL(a)         (-EINVAL)
83 #endif
84 #ifndef SET_TSC_CTL
85 # define SET_TSC_CTL(a)         (-EINVAL)
86 #endif
87
88 /*
89  * this is where the system-wide overflow UID and GID are defined, for
90  * architectures that now have 32-bit UID/GID but didn't in the past
91  */
92
93 int overflowuid = DEFAULT_OVERFLOWUID;
94 int overflowgid = DEFAULT_OVERFLOWGID;
95
96 #ifdef CONFIG_UID16
97 EXPORT_SYMBOL(overflowuid);
98 EXPORT_SYMBOL(overflowgid);
99 #endif
100
101 /*
102  * the same as above, but for filesystems which can only store a 16-bit
103  * UID and GID. as such, this is needed on all architectures
104  */
105
106 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
107 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
108
109 EXPORT_SYMBOL(fs_overflowuid);
110 EXPORT_SYMBOL(fs_overflowgid);
111
112 /*
113  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
114  */
115
116 int C_A_D = 1;
117 struct pid *cad_pid;
118 EXPORT_SYMBOL(cad_pid);
119
120 /*
121  * If set, this is used for preparing the system to power off.
122  */
123
124 void (*pm_power_off_prepare)(void);
125
126 /*
127  * Returns true if current's euid is same as p's uid or euid,
128  * or has CAP_SYS_NICE to p's user_ns.
129  *
130  * Called with rcu_read_lock, creds are safe
131  */
132 static bool set_one_prio_perm(struct task_struct *p)
133 {
134         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
135
136         if (pcred->user->user_ns == cred->user->user_ns &&
137             (pcred->uid  == cred->euid ||
138              pcred->euid == cred->euid))
139                 return true;
140         if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
141                 return true;
142         return false;
143 }
144
145 /*
146  * set the priority of a task
147  * - the caller must hold the RCU read lock
148  */
149 static int set_one_prio(struct task_struct *p, int niceval, int error)
150 {
151         int no_nice;
152
153         if (!set_one_prio_perm(p)) {
154                 error = -EPERM;
155                 goto out;
156         }
157         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
158                 error = -EACCES;
159                 goto out;
160         }
161         no_nice = security_task_setnice(p, niceval);
162         if (no_nice) {
163                 error = no_nice;
164                 goto out;
165         }
166         if (error == -ESRCH)
167                 error = 0;
168         set_user_nice(p, niceval);
169 out:
170         return error;
171 }
172
173 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
174 {
175         struct task_struct *g, *p;
176         struct user_struct *user;
177         const struct cred *cred = current_cred();
178         int error = -EINVAL;
179         struct pid *pgrp;
180
181         if (which > PRIO_USER || which < PRIO_PROCESS)
182                 goto out;
183
184         /* normalize: avoid signed division (rounding problems) */
185         error = -ESRCH;
186         if (niceval < -20)
187                 niceval = -20;
188         if (niceval > 19)
189                 niceval = 19;
190
191         rcu_read_lock();
192         read_lock(&tasklist_lock);
193         switch (which) {
194                 case PRIO_PROCESS:
195                         if (who)
196                                 p = find_task_by_vpid(who);
197                         else
198                                 p = current;
199                         if (p)
200                                 error = set_one_prio(p, niceval, error);
201                         break;
202                 case PRIO_PGRP:
203                         if (who)
204                                 pgrp = find_vpid(who);
205                         else
206                                 pgrp = task_pgrp(current);
207                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
208                                 error = set_one_prio(p, niceval, error);
209                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
210                         break;
211                 case PRIO_USER:
212                         user = (struct user_struct *) cred->user;
213                         if (!who)
214                                 who = cred->uid;
215                         else if ((who != cred->uid) &&
216                                  !(user = find_user(who)))
217                                 goto out_unlock;        /* No processes for this user */
218
219                         do_each_thread(g, p) {
220                                 if (__task_cred(p)->uid == who)
221                                         error = set_one_prio(p, niceval, error);
222                         } while_each_thread(g, p);
223                         if (who != cred->uid)
224                                 free_uid(user);         /* For find_user() */
225                         break;
226         }
227 out_unlock:
228         read_unlock(&tasklist_lock);
229         rcu_read_unlock();
230 out:
231         return error;
232 }
233
234 /*
235  * Ugh. To avoid negative return values, "getpriority()" will
236  * not return the normal nice-value, but a negated value that
237  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
238  * to stay compatible.
239  */
240 SYSCALL_DEFINE2(getpriority, int, which, int, who)
241 {
242         struct task_struct *g, *p;
243         struct user_struct *user;
244         const struct cred *cred = current_cred();
245         long niceval, retval = -ESRCH;
246         struct pid *pgrp;
247
248         if (which > PRIO_USER || which < PRIO_PROCESS)
249                 return -EINVAL;
250
251         rcu_read_lock();
252         read_lock(&tasklist_lock);
253         switch (which) {
254                 case PRIO_PROCESS:
255                         if (who)
256                                 p = find_task_by_vpid(who);
257                         else
258                                 p = current;
259                         if (p) {
260                                 niceval = 20 - task_nice(p);
261                                 if (niceval > retval)
262                                         retval = niceval;
263                         }
264                         break;
265                 case PRIO_PGRP:
266                         if (who)
267                                 pgrp = find_vpid(who);
268                         else
269                                 pgrp = task_pgrp(current);
270                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
271                                 niceval = 20 - task_nice(p);
272                                 if (niceval > retval)
273                                         retval = niceval;
274                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
275                         break;
276                 case PRIO_USER:
277                         user = (struct user_struct *) cred->user;
278                         if (!who)
279                                 who = cred->uid;
280                         else if ((who != cred->uid) &&
281                                  !(user = find_user(who)))
282                                 goto out_unlock;        /* No processes for this user */
283
284                         do_each_thread(g, p) {
285                                 if (__task_cred(p)->uid == who) {
286                                         niceval = 20 - task_nice(p);
287                                         if (niceval > retval)
288                                                 retval = niceval;
289                                 }
290                         } while_each_thread(g, p);
291                         if (who != cred->uid)
292                                 free_uid(user);         /* for find_user() */
293                         break;
294         }
295 out_unlock:
296         read_unlock(&tasklist_lock);
297         rcu_read_unlock();
298
299         return retval;
300 }
301
302 /**
303  *      emergency_restart - reboot the system
304  *
305  *      Without shutting down any hardware or taking any locks
306  *      reboot the system.  This is called when we know we are in
307  *      trouble so this is our best effort to reboot.  This is
308  *      safe to call in interrupt context.
309  */
310 void emergency_restart(void)
311 {
312         kmsg_dump(KMSG_DUMP_EMERG);
313         machine_emergency_restart();
314 }
315 EXPORT_SYMBOL_GPL(emergency_restart);
316
317 void kernel_restart_prepare(char *cmd)
318 {
319         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
320         system_state = SYSTEM_RESTART;
321         usermodehelper_disable();
322         device_shutdown();
323         syscore_shutdown();
324 }
325
326 /**
327  *      register_reboot_notifier - Register function to be called at reboot time
328  *      @nb: Info about notifier function to be called
329  *
330  *      Registers a function with the list of functions
331  *      to be called at reboot time.
332  *
333  *      Currently always returns zero, as blocking_notifier_chain_register()
334  *      always returns zero.
335  */
336 int register_reboot_notifier(struct notifier_block *nb)
337 {
338         return blocking_notifier_chain_register(&reboot_notifier_list, nb);
339 }
340 EXPORT_SYMBOL(register_reboot_notifier);
341
342 /**
343  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
344  *      @nb: Hook to be unregistered
345  *
346  *      Unregisters a previously registered reboot
347  *      notifier function.
348  *
349  *      Returns zero on success, or %-ENOENT on failure.
350  */
351 int unregister_reboot_notifier(struct notifier_block *nb)
352 {
353         return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
354 }
355 EXPORT_SYMBOL(unregister_reboot_notifier);
356
357 /**
358  *      kernel_restart - reboot the system
359  *      @cmd: pointer to buffer containing command to execute for restart
360  *              or %NULL
361  *
362  *      Shutdown everything and perform a clean reboot.
363  *      This is not safe to call in interrupt context.
364  */
365 void kernel_restart(char *cmd)
366 {
367         kernel_restart_prepare(cmd);
368         if (!cmd)
369                 printk(KERN_EMERG "Restarting system.\n");
370         else
371                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
372         kmsg_dump(KMSG_DUMP_RESTART);
373         machine_restart(cmd);
374 }
375 EXPORT_SYMBOL_GPL(kernel_restart);
376
377 static void kernel_shutdown_prepare(enum system_states state)
378 {
379         blocking_notifier_call_chain(&reboot_notifier_list,
380                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
381         system_state = state;
382         usermodehelper_disable();
383         device_shutdown();
384 }
385 /**
386  *      kernel_halt - halt the system
387  *
388  *      Shutdown everything and perform a clean system halt.
389  */
390 void kernel_halt(void)
391 {
392         kernel_shutdown_prepare(SYSTEM_HALT);
393         syscore_shutdown();
394         printk(KERN_EMERG "System halted.\n");
395         kmsg_dump(KMSG_DUMP_HALT);
396         machine_halt();
397 }
398
399 EXPORT_SYMBOL_GPL(kernel_halt);
400
401 /**
402  *      kernel_power_off - power_off the system
403  *
404  *      Shutdown everything and perform a clean system power_off.
405  */
406 void kernel_power_off(void)
407 {
408         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
409         if (pm_power_off_prepare)
410                 pm_power_off_prepare();
411         disable_nonboot_cpus();
412         syscore_shutdown();
413         printk(KERN_EMERG "Power down.\n");
414         kmsg_dump(KMSG_DUMP_POWEROFF);
415         machine_power_off();
416 }
417 EXPORT_SYMBOL_GPL(kernel_power_off);
418
419 static DEFINE_MUTEX(reboot_mutex);
420
421 /*
422  * Reboot system call: for obvious reasons only root may call it,
423  * and even root needs to set up some magic numbers in the registers
424  * so that some mistake won't make this reboot the whole machine.
425  * You can also set the meaning of the ctrl-alt-del-key here.
426  *
427  * reboot doesn't sync: do that yourself before calling this.
428  */
429 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
430                 void __user *, arg)
431 {
432         char buffer[256];
433         int ret = 0;
434
435         /* We only trust the superuser with rebooting the system. */
436         if (!capable(CAP_SYS_BOOT))
437                 return -EPERM;
438
439         /* For safety, we require "magic" arguments. */
440         if (magic1 != LINUX_REBOOT_MAGIC1 ||
441             (magic2 != LINUX_REBOOT_MAGIC2 &&
442                         magic2 != LINUX_REBOOT_MAGIC2A &&
443                         magic2 != LINUX_REBOOT_MAGIC2B &&
444                         magic2 != LINUX_REBOOT_MAGIC2C))
445                 return -EINVAL;
446
447         /* Instead of trying to make the power_off code look like
448          * halt when pm_power_off is not set do it the easy way.
449          */
450         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
451                 cmd = LINUX_REBOOT_CMD_HALT;
452
453         mutex_lock(&reboot_mutex);
454         switch (cmd) {
455         case LINUX_REBOOT_CMD_RESTART:
456                 kernel_restart(NULL);
457                 break;
458
459         case LINUX_REBOOT_CMD_CAD_ON:
460                 C_A_D = 1;
461                 break;
462
463         case LINUX_REBOOT_CMD_CAD_OFF:
464                 C_A_D = 0;
465                 break;
466
467         case LINUX_REBOOT_CMD_HALT:
468                 kernel_halt();
469                 do_exit(0);
470                 panic("cannot halt");
471
472         case LINUX_REBOOT_CMD_POWER_OFF:
473                 kernel_power_off();
474                 do_exit(0);
475                 break;
476
477         case LINUX_REBOOT_CMD_RESTART2:
478                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
479                         ret = -EFAULT;
480                         break;
481                 }
482                 buffer[sizeof(buffer) - 1] = '\0';
483
484                 kernel_restart(buffer);
485                 break;
486
487 #ifdef CONFIG_KEXEC
488         case LINUX_REBOOT_CMD_KEXEC:
489                 ret = kernel_kexec();
490                 break;
491 #endif
492
493 #ifdef CONFIG_HIBERNATION
494         case LINUX_REBOOT_CMD_SW_SUSPEND:
495                 ret = hibernate();
496                 break;
497 #endif
498
499         default:
500                 ret = -EINVAL;
501                 break;
502         }
503         mutex_unlock(&reboot_mutex);
504         return ret;
505 }
506
507 static void deferred_cad(struct work_struct *dummy)
508 {
509         kernel_restart(NULL);
510 }
511
512 /*
513  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
514  * As it's called within an interrupt, it may NOT sync: the only choice
515  * is whether to reboot at once, or just ignore the ctrl-alt-del.
516  */
517 void ctrl_alt_del(void)
518 {
519         static DECLARE_WORK(cad_work, deferred_cad);
520
521         if (C_A_D)
522                 schedule_work(&cad_work);
523         else
524                 kill_cad_pid(SIGINT, 1);
525 }
526         
527 /*
528  * Unprivileged users may change the real gid to the effective gid
529  * or vice versa.  (BSD-style)
530  *
531  * If you set the real gid at all, or set the effective gid to a value not
532  * equal to the real gid, then the saved gid is set to the new effective gid.
533  *
534  * This makes it possible for a setgid program to completely drop its
535  * privileges, which is often a useful assertion to make when you are doing
536  * a security audit over a program.
537  *
538  * The general idea is that a program which uses just setregid() will be
539  * 100% compatible with BSD.  A program which uses just setgid() will be
540  * 100% compatible with POSIX with saved IDs. 
541  *
542  * SMP: There are not races, the GIDs are checked only by filesystem
543  *      operations (as far as semantic preservation is concerned).
544  */
545 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
546 {
547         const struct cred *old;
548         struct cred *new;
549         int retval;
550
551         new = prepare_creds();
552         if (!new)
553                 return -ENOMEM;
554         old = current_cred();
555
556         retval = -EPERM;
557         if (rgid != (gid_t) -1) {
558                 if (old->gid == rgid ||
559                     old->egid == rgid ||
560                     nsown_capable(CAP_SETGID))
561                         new->gid = rgid;
562                 else
563                         goto error;
564         }
565         if (egid != (gid_t) -1) {
566                 if (old->gid == egid ||
567                     old->egid == egid ||
568                     old->sgid == egid ||
569                     nsown_capable(CAP_SETGID))
570                         new->egid = egid;
571                 else
572                         goto error;
573         }
574
575         if (rgid != (gid_t) -1 ||
576             (egid != (gid_t) -1 && egid != old->gid))
577                 new->sgid = new->egid;
578         new->fsgid = new->egid;
579
580         return commit_creds(new);
581
582 error:
583         abort_creds(new);
584         return retval;
585 }
586
587 /*
588  * setgid() is implemented like SysV w/ SAVED_IDS 
589  *
590  * SMP: Same implicit races as above.
591  */
592 SYSCALL_DEFINE1(setgid, gid_t, gid)
593 {
594         const struct cred *old;
595         struct cred *new;
596         int retval;
597
598         new = prepare_creds();
599         if (!new)
600                 return -ENOMEM;
601         old = current_cred();
602
603         retval = -EPERM;
604         if (nsown_capable(CAP_SETGID))
605                 new->gid = new->egid = new->sgid = new->fsgid = gid;
606         else if (gid == old->gid || gid == old->sgid)
607                 new->egid = new->fsgid = gid;
608         else
609                 goto error;
610
611         return commit_creds(new);
612
613 error:
614         abort_creds(new);
615         return retval;
616 }
617
618 /*
619  * change the user struct in a credentials set to match the new UID
620  */
621 static int set_user(struct cred *new)
622 {
623         struct user_struct *new_user;
624
625         new_user = alloc_uid(current_user_ns(), new->uid);
626         if (!new_user)
627                 return -EAGAIN;
628
629         /*
630          * We don't fail in case of NPROC limit excess here because too many
631          * poorly written programs don't check set*uid() return code, assuming
632          * it never fails if called by root.  We may still enforce NPROC limit
633          * for programs doing set*uid()+execve() by harmlessly deferring the
634          * failure to the execve() stage.
635          */
636         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
637                         new_user != INIT_USER)
638                 current->flags |= PF_NPROC_EXCEEDED;
639         else
640                 current->flags &= ~PF_NPROC_EXCEEDED;
641
642         free_uid(new->user);
643         new->user = new_user;
644         return 0;
645 }
646
647 /*
648  * Unprivileged users may change the real uid to the effective uid
649  * or vice versa.  (BSD-style)
650  *
651  * If you set the real uid at all, or set the effective uid to a value not
652  * equal to the real uid, then the saved uid is set to the new effective uid.
653  *
654  * This makes it possible for a setuid program to completely drop its
655  * privileges, which is often a useful assertion to make when you are doing
656  * a security audit over a program.
657  *
658  * The general idea is that a program which uses just setreuid() will be
659  * 100% compatible with BSD.  A program which uses just setuid() will be
660  * 100% compatible with POSIX with saved IDs. 
661  */
662 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
663 {
664         const struct cred *old;
665         struct cred *new;
666         int retval;
667
668         new = prepare_creds();
669         if (!new)
670                 return -ENOMEM;
671         old = current_cred();
672
673         retval = -EPERM;
674         if (ruid != (uid_t) -1) {
675                 new->uid = ruid;
676                 if (old->uid != ruid &&
677                     old->euid != ruid &&
678                     !nsown_capable(CAP_SETUID))
679                         goto error;
680         }
681
682         if (euid != (uid_t) -1) {
683                 new->euid = euid;
684                 if (old->uid != euid &&
685                     old->euid != euid &&
686                     old->suid != euid &&
687                     !nsown_capable(CAP_SETUID))
688                         goto error;
689         }
690
691         if (new->uid != old->uid) {
692                 retval = set_user(new);
693                 if (retval < 0)
694                         goto error;
695         }
696         if (ruid != (uid_t) -1 ||
697             (euid != (uid_t) -1 && euid != old->uid))
698                 new->suid = new->euid;
699         new->fsuid = new->euid;
700
701         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
702         if (retval < 0)
703                 goto error;
704
705         return commit_creds(new);
706
707 error:
708         abort_creds(new);
709         return retval;
710 }
711                 
712 /*
713  * setuid() is implemented like SysV with SAVED_IDS 
714  * 
715  * Note that SAVED_ID's is deficient in that a setuid root program
716  * like sendmail, for example, cannot set its uid to be a normal 
717  * user and then switch back, because if you're root, setuid() sets
718  * the saved uid too.  If you don't like this, blame the bright people
719  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
720  * will allow a root program to temporarily drop privileges and be able to
721  * regain them by swapping the real and effective uid.  
722  */
723 SYSCALL_DEFINE1(setuid, uid_t, uid)
724 {
725         const struct cred *old;
726         struct cred *new;
727         int retval;
728
729         new = prepare_creds();
730         if (!new)
731                 return -ENOMEM;
732         old = current_cred();
733
734         retval = -EPERM;
735         if (nsown_capable(CAP_SETUID)) {
736                 new->suid = new->uid = uid;
737                 if (uid != old->uid) {
738                         retval = set_user(new);
739                         if (retval < 0)
740                                 goto error;
741                 }
742         } else if (uid != old->uid && uid != new->suid) {
743                 goto error;
744         }
745
746         new->fsuid = new->euid = uid;
747
748         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
749         if (retval < 0)
750                 goto error;
751
752         return commit_creds(new);
753
754 error:
755         abort_creds(new);
756         return retval;
757 }
758
759
760 /*
761  * This function implements a generic ability to update ruid, euid,
762  * and suid.  This allows you to implement the 4.4 compatible seteuid().
763  */
764 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
765 {
766         const struct cred *old;
767         struct cred *new;
768         int retval;
769
770         new = prepare_creds();
771         if (!new)
772                 return -ENOMEM;
773
774         old = current_cred();
775
776         retval = -EPERM;
777         if (!nsown_capable(CAP_SETUID)) {
778                 if (ruid != (uid_t) -1 && ruid != old->uid &&
779                     ruid != old->euid  && ruid != old->suid)
780                         goto error;
781                 if (euid != (uid_t) -1 && euid != old->uid &&
782                     euid != old->euid  && euid != old->suid)
783                         goto error;
784                 if (suid != (uid_t) -1 && suid != old->uid &&
785                     suid != old->euid  && suid != old->suid)
786                         goto error;
787         }
788
789         if (ruid != (uid_t) -1) {
790                 new->uid = ruid;
791                 if (ruid != old->uid) {
792                         retval = set_user(new);
793                         if (retval < 0)
794                                 goto error;
795                 }
796         }
797         if (euid != (uid_t) -1)
798                 new->euid = euid;
799         if (suid != (uid_t) -1)
800                 new->suid = suid;
801         new->fsuid = new->euid;
802
803         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
804         if (retval < 0)
805                 goto error;
806
807         return commit_creds(new);
808
809 error:
810         abort_creds(new);
811         return retval;
812 }
813
814 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
815 {
816         const struct cred *cred = current_cred();
817         int retval;
818
819         if (!(retval   = put_user(cred->uid,  ruid)) &&
820             !(retval   = put_user(cred->euid, euid)))
821                 retval = put_user(cred->suid, suid);
822
823         return retval;
824 }
825
826 /*
827  * Same as above, but for rgid, egid, sgid.
828  */
829 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
830 {
831         const struct cred *old;
832         struct cred *new;
833         int retval;
834
835         new = prepare_creds();
836         if (!new)
837                 return -ENOMEM;
838         old = current_cred();
839
840         retval = -EPERM;
841         if (!nsown_capable(CAP_SETGID)) {
842                 if (rgid != (gid_t) -1 && rgid != old->gid &&
843                     rgid != old->egid  && rgid != old->sgid)
844                         goto error;
845                 if (egid != (gid_t) -1 && egid != old->gid &&
846                     egid != old->egid  && egid != old->sgid)
847                         goto error;
848                 if (sgid != (gid_t) -1 && sgid != old->gid &&
849                     sgid != old->egid  && sgid != old->sgid)
850                         goto error;
851         }
852
853         if (rgid != (gid_t) -1)
854                 new->gid = rgid;
855         if (egid != (gid_t) -1)
856                 new->egid = egid;
857         if (sgid != (gid_t) -1)
858                 new->sgid = sgid;
859         new->fsgid = new->egid;
860
861         return commit_creds(new);
862
863 error:
864         abort_creds(new);
865         return retval;
866 }
867
868 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
869 {
870         const struct cred *cred = current_cred();
871         int retval;
872
873         if (!(retval   = put_user(cred->gid,  rgid)) &&
874             !(retval   = put_user(cred->egid, egid)))
875                 retval = put_user(cred->sgid, sgid);
876
877         return retval;
878 }
879
880
881 /*
882  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
883  * is used for "access()" and for the NFS daemon (letting nfsd stay at
884  * whatever uid it wants to). It normally shadows "euid", except when
885  * explicitly set by setfsuid() or for access..
886  */
887 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
888 {
889         const struct cred *old;
890         struct cred *new;
891         uid_t old_fsuid;
892
893         new = prepare_creds();
894         if (!new)
895                 return current_fsuid();
896         old = current_cred();
897         old_fsuid = old->fsuid;
898
899         if (uid == old->uid  || uid == old->euid  ||
900             uid == old->suid || uid == old->fsuid ||
901             nsown_capable(CAP_SETUID)) {
902                 if (uid != old_fsuid) {
903                         new->fsuid = uid;
904                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
905                                 goto change_okay;
906                 }
907         }
908
909         abort_creds(new);
910         return old_fsuid;
911
912 change_okay:
913         commit_creds(new);
914         return old_fsuid;
915 }
916
917 /*
918  * Samma på svenska..
919  */
920 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
921 {
922         const struct cred *old;
923         struct cred *new;
924         gid_t old_fsgid;
925
926         new = prepare_creds();
927         if (!new)
928                 return current_fsgid();
929         old = current_cred();
930         old_fsgid = old->fsgid;
931
932         if (gid == old->gid  || gid == old->egid  ||
933             gid == old->sgid || gid == old->fsgid ||
934             nsown_capable(CAP_SETGID)) {
935                 if (gid != old_fsgid) {
936                         new->fsgid = gid;
937                         goto change_okay;
938                 }
939         }
940
941         abort_creds(new);
942         return old_fsgid;
943
944 change_okay:
945         commit_creds(new);
946         return old_fsgid;
947 }
948
949 void do_sys_times(struct tms *tms)
950 {
951         cputime_t tgutime, tgstime, cutime, cstime;
952
953         spin_lock_irq(&current->sighand->siglock);
954         thread_group_times(current, &tgutime, &tgstime);
955         cutime = current->signal->cutime;
956         cstime = current->signal->cstime;
957         spin_unlock_irq(&current->sighand->siglock);
958         tms->tms_utime = cputime_to_clock_t(tgutime);
959         tms->tms_stime = cputime_to_clock_t(tgstime);
960         tms->tms_cutime = cputime_to_clock_t(cutime);
961         tms->tms_cstime = cputime_to_clock_t(cstime);
962 }
963
964 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
965 {
966         if (tbuf) {
967                 struct tms tmp;
968
969                 do_sys_times(&tmp);
970                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
971                         return -EFAULT;
972         }
973         force_successful_syscall_return();
974         return (long) jiffies_64_to_clock_t(get_jiffies_64());
975 }
976
977 /*
978  * This needs some heavy checking ...
979  * I just haven't the stomach for it. I also don't fully
980  * understand sessions/pgrp etc. Let somebody who does explain it.
981  *
982  * OK, I think I have the protection semantics right.... this is really
983  * only important on a multi-user system anyway, to make sure one user
984  * can't send a signal to a process owned by another.  -TYT, 12/12/91
985  *
986  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
987  * LBT 04.03.94
988  */
989 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
990 {
991         struct task_struct *p;
992         struct task_struct *group_leader = current->group_leader;
993         struct pid *pgrp;
994         int err;
995
996         if (!pid)
997                 pid = task_pid_vnr(group_leader);
998         if (!pgid)
999                 pgid = pid;
1000         if (pgid < 0)
1001                 return -EINVAL;
1002         rcu_read_lock();
1003
1004         /* From this point forward we keep holding onto the tasklist lock
1005          * so that our parent does not change from under us. -DaveM
1006          */
1007         write_lock_irq(&tasklist_lock);
1008
1009         err = -ESRCH;
1010         p = find_task_by_vpid(pid);
1011         if (!p)
1012                 goto out;
1013
1014         err = -EINVAL;
1015         if (!thread_group_leader(p))
1016                 goto out;
1017
1018         if (same_thread_group(p->real_parent, group_leader)) {
1019                 err = -EPERM;
1020                 if (task_session(p) != task_session(group_leader))
1021                         goto out;
1022                 err = -EACCES;
1023                 if (p->did_exec)
1024                         goto out;
1025         } else {
1026                 err = -ESRCH;
1027                 if (p != group_leader)
1028                         goto out;
1029         }
1030
1031         err = -EPERM;
1032         if (p->signal->leader)
1033                 goto out;
1034
1035         pgrp = task_pid(p);
1036         if (pgid != pid) {
1037                 struct task_struct *g;
1038
1039                 pgrp = find_vpid(pgid);
1040                 g = pid_task(pgrp, PIDTYPE_PGID);
1041                 if (!g || task_session(g) != task_session(group_leader))
1042                         goto out;
1043         }
1044
1045         err = security_task_setpgid(p, pgid);
1046         if (err)
1047                 goto out;
1048
1049         if (task_pgrp(p) != pgrp)
1050                 change_pid(p, PIDTYPE_PGID, pgrp);
1051
1052         err = 0;
1053 out:
1054         /* All paths lead to here, thus we are safe. -DaveM */
1055         write_unlock_irq(&tasklist_lock);
1056         rcu_read_unlock();
1057         return err;
1058 }
1059
1060 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1061 {
1062         struct task_struct *p;
1063         struct pid *grp;
1064         int retval;
1065
1066         rcu_read_lock();
1067         if (!pid)
1068                 grp = task_pgrp(current);
1069         else {
1070                 retval = -ESRCH;
1071                 p = find_task_by_vpid(pid);
1072                 if (!p)
1073                         goto out;
1074                 grp = task_pgrp(p);
1075                 if (!grp)
1076                         goto out;
1077
1078                 retval = security_task_getpgid(p);
1079                 if (retval)
1080                         goto out;
1081         }
1082         retval = pid_vnr(grp);
1083 out:
1084         rcu_read_unlock();
1085         return retval;
1086 }
1087
1088 #ifdef __ARCH_WANT_SYS_GETPGRP
1089
1090 SYSCALL_DEFINE0(getpgrp)
1091 {
1092         return sys_getpgid(0);
1093 }
1094
1095 #endif
1096
1097 SYSCALL_DEFINE1(getsid, pid_t, pid)
1098 {
1099         struct task_struct *p;
1100         struct pid *sid;
1101         int retval;
1102
1103         rcu_read_lock();
1104         if (!pid)
1105                 sid = task_session(current);
1106         else {
1107                 retval = -ESRCH;
1108                 p = find_task_by_vpid(pid);
1109                 if (!p)
1110                         goto out;
1111                 sid = task_session(p);
1112                 if (!sid)
1113                         goto out;
1114
1115                 retval = security_task_getsid(p);
1116                 if (retval)
1117                         goto out;
1118         }
1119         retval = pid_vnr(sid);
1120 out:
1121         rcu_read_unlock();
1122         return retval;
1123 }
1124
1125 SYSCALL_DEFINE0(setsid)
1126 {
1127         struct task_struct *group_leader = current->group_leader;
1128         struct pid *sid = task_pid(group_leader);
1129         pid_t session = pid_vnr(sid);
1130         int err = -EPERM;
1131
1132         write_lock_irq(&tasklist_lock);
1133         /* Fail if I am already a session leader */
1134         if (group_leader->signal->leader)
1135                 goto out;
1136
1137         /* Fail if a process group id already exists that equals the
1138          * proposed session id.
1139          */
1140         if (pid_task(sid, PIDTYPE_PGID))
1141                 goto out;
1142
1143         group_leader->signal->leader = 1;
1144         __set_special_pids(sid);
1145
1146         proc_clear_tty(group_leader);
1147
1148         err = session;
1149 out:
1150         write_unlock_irq(&tasklist_lock);
1151         if (err > 0) {
1152                 proc_sid_connector(group_leader);
1153                 sched_autogroup_create_attach(group_leader);
1154         }
1155         return err;
1156 }
1157
1158 DECLARE_RWSEM(uts_sem);
1159
1160 #ifdef COMPAT_UTS_MACHINE
1161 #define override_architecture(name) \
1162         (personality(current->personality) == PER_LINUX32 && \
1163          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1164                       sizeof(COMPAT_UTS_MACHINE)))
1165 #else
1166 #define override_architecture(name)     0
1167 #endif
1168
1169 /*
1170  * Work around broken programs that cannot handle "Linux 3.0".
1171  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1172  */
1173 static int override_release(char __user *release, int len)
1174 {
1175         int ret = 0;
1176         char buf[65];
1177
1178         if (current->personality & UNAME26) {
1179                 char *rest = UTS_RELEASE;
1180                 int ndots = 0;
1181                 unsigned v;
1182
1183                 while (*rest) {
1184                         if (*rest == '.' && ++ndots >= 3)
1185                                 break;
1186                         if (!isdigit(*rest) && *rest != '.')
1187                                 break;
1188                         rest++;
1189                 }
1190                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1191                 snprintf(buf, len, "2.6.%u%s", v, rest);
1192                 ret = copy_to_user(release, buf, len);
1193         }
1194         return ret;
1195 }
1196
1197 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1198 {
1199         int errno = 0;
1200
1201         down_read(&uts_sem);
1202         if (copy_to_user(name, utsname(), sizeof *name))
1203                 errno = -EFAULT;
1204         up_read(&uts_sem);
1205
1206         if (!errno && override_release(name->release, sizeof(name->release)))
1207                 errno = -EFAULT;
1208         if (!errno && override_architecture(name))
1209                 errno = -EFAULT;
1210         return errno;
1211 }
1212
1213 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1214 /*
1215  * Old cruft
1216  */
1217 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1218 {
1219         int error = 0;
1220
1221         if (!name)
1222                 return -EFAULT;
1223
1224         down_read(&uts_sem);
1225         if (copy_to_user(name, utsname(), sizeof(*name)))
1226                 error = -EFAULT;
1227         up_read(&uts_sem);
1228
1229         if (!error && override_release(name->release, sizeof(name->release)))
1230                 error = -EFAULT;
1231         if (!error && override_architecture(name))
1232                 error = -EFAULT;
1233         return error;
1234 }
1235
1236 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1237 {
1238         int error;
1239
1240         if (!name)
1241                 return -EFAULT;
1242         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1243                 return -EFAULT;
1244
1245         down_read(&uts_sem);
1246         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1247                                __OLD_UTS_LEN);
1248         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1249         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1250                                 __OLD_UTS_LEN);
1251         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1252         error |= __copy_to_user(&name->release, &utsname()->release,
1253                                 __OLD_UTS_LEN);
1254         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1255         error |= __copy_to_user(&name->version, &utsname()->version,
1256                                 __OLD_UTS_LEN);
1257         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1258         error |= __copy_to_user(&name->machine, &utsname()->machine,
1259                                 __OLD_UTS_LEN);
1260         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1261         up_read(&uts_sem);
1262
1263         if (!error && override_architecture(name))
1264                 error = -EFAULT;
1265         if (!error && override_release(name->release, sizeof(name->release)))
1266                 error = -EFAULT;
1267         return error ? -EFAULT : 0;
1268 }
1269 #endif
1270
1271 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1272 {
1273         int errno;
1274         char tmp[__NEW_UTS_LEN];
1275
1276         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1277                 return -EPERM;
1278
1279         if (len < 0 || len > __NEW_UTS_LEN)
1280                 return -EINVAL;
1281         down_write(&uts_sem);
1282         errno = -EFAULT;
1283         if (!copy_from_user(tmp, name, len)) {
1284                 struct new_utsname *u = utsname();
1285
1286                 memcpy(u->nodename, tmp, len);
1287                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1288                 errno = 0;
1289         }
1290         uts_proc_notify(UTS_PROC_HOSTNAME);
1291         up_write(&uts_sem);
1292         return errno;
1293 }
1294
1295 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1296
1297 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1298 {
1299         int i, errno;
1300         struct new_utsname *u;
1301
1302         if (len < 0)
1303                 return -EINVAL;
1304         down_read(&uts_sem);
1305         u = utsname();
1306         i = 1 + strlen(u->nodename);
1307         if (i > len)
1308                 i = len;
1309         errno = 0;
1310         if (copy_to_user(name, u->nodename, i))
1311                 errno = -EFAULT;
1312         up_read(&uts_sem);
1313         return errno;
1314 }
1315
1316 #endif
1317
1318 /*
1319  * Only setdomainname; getdomainname can be implemented by calling
1320  * uname()
1321  */
1322 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1323 {
1324         int errno;
1325         char tmp[__NEW_UTS_LEN];
1326
1327         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1328                 return -EPERM;
1329         if (len < 0 || len > __NEW_UTS_LEN)
1330                 return -EINVAL;
1331
1332         down_write(&uts_sem);
1333         errno = -EFAULT;
1334         if (!copy_from_user(tmp, name, len)) {
1335                 struct new_utsname *u = utsname();
1336
1337                 memcpy(u->domainname, tmp, len);
1338                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1339                 errno = 0;
1340         }
1341         uts_proc_notify(UTS_PROC_DOMAINNAME);
1342         up_write(&uts_sem);
1343         return errno;
1344 }
1345
1346 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1347 {
1348         struct rlimit value;
1349         int ret;
1350
1351         ret = do_prlimit(current, resource, NULL, &value);
1352         if (!ret)
1353                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1354
1355         return ret;
1356 }
1357
1358 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1359
1360 /*
1361  *      Back compatibility for getrlimit. Needed for some apps.
1362  */
1363  
1364 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1365                 struct rlimit __user *, rlim)
1366 {
1367         struct rlimit x;
1368         if (resource >= RLIM_NLIMITS)
1369                 return -EINVAL;
1370
1371         task_lock(current->group_leader);
1372         x = current->signal->rlim[resource];
1373         task_unlock(current->group_leader);
1374         if (x.rlim_cur > 0x7FFFFFFF)
1375                 x.rlim_cur = 0x7FFFFFFF;
1376         if (x.rlim_max > 0x7FFFFFFF)
1377                 x.rlim_max = 0x7FFFFFFF;
1378         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1379 }
1380
1381 #endif
1382
1383 static inline bool rlim64_is_infinity(__u64 rlim64)
1384 {
1385 #if BITS_PER_LONG < 64
1386         return rlim64 >= ULONG_MAX;
1387 #else
1388         return rlim64 == RLIM64_INFINITY;
1389 #endif
1390 }
1391
1392 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1393 {
1394         if (rlim->rlim_cur == RLIM_INFINITY)
1395                 rlim64->rlim_cur = RLIM64_INFINITY;
1396         else
1397                 rlim64->rlim_cur = rlim->rlim_cur;
1398         if (rlim->rlim_max == RLIM_INFINITY)
1399                 rlim64->rlim_max = RLIM64_INFINITY;
1400         else
1401                 rlim64->rlim_max = rlim->rlim_max;
1402 }
1403
1404 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1405 {
1406         if (rlim64_is_infinity(rlim64->rlim_cur))
1407                 rlim->rlim_cur = RLIM_INFINITY;
1408         else
1409                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1410         if (rlim64_is_infinity(rlim64->rlim_max))
1411                 rlim->rlim_max = RLIM_INFINITY;
1412         else
1413                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1414 }
1415
1416 /* make sure you are allowed to change @tsk limits before calling this */
1417 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1418                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1419 {
1420         struct rlimit *rlim;
1421         int retval = 0;
1422
1423         if (resource >= RLIM_NLIMITS)
1424                 return -EINVAL;
1425         if (new_rlim) {
1426                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1427                         return -EINVAL;
1428                 if (resource == RLIMIT_NOFILE &&
1429                                 new_rlim->rlim_max > sysctl_nr_open)
1430                         return -EPERM;
1431         }
1432
1433         /* protect tsk->signal and tsk->sighand from disappearing */
1434         read_lock(&tasklist_lock);
1435         if (!tsk->sighand) {
1436                 retval = -ESRCH;
1437                 goto out;
1438         }
1439
1440         rlim = tsk->signal->rlim + resource;
1441         task_lock(tsk->group_leader);
1442         if (new_rlim) {
1443                 /* Keep the capable check against init_user_ns until
1444                    cgroups can contain all limits */
1445                 if (new_rlim->rlim_max > rlim->rlim_max &&
1446                                 !capable(CAP_SYS_RESOURCE))
1447                         retval = -EPERM;
1448                 if (!retval)
1449                         retval = security_task_setrlimit(tsk->group_leader,
1450                                         resource, new_rlim);
1451                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1452                         /*
1453                          * The caller is asking for an immediate RLIMIT_CPU
1454                          * expiry.  But we use the zero value to mean "it was
1455                          * never set".  So let's cheat and make it one second
1456                          * instead
1457                          */
1458                         new_rlim->rlim_cur = 1;
1459                 }
1460         }
1461         if (!retval) {
1462                 if (old_rlim)
1463                         *old_rlim = *rlim;
1464                 if (new_rlim)
1465                         *rlim = *new_rlim;
1466         }
1467         task_unlock(tsk->group_leader);
1468
1469         /*
1470          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1471          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1472          * very long-standing error, and fixing it now risks breakage of
1473          * applications, so we live with it
1474          */
1475          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1476                          new_rlim->rlim_cur != RLIM_INFINITY)
1477                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1478 out:
1479         read_unlock(&tasklist_lock);
1480         return retval;
1481 }
1482
1483 /* rcu lock must be held */
1484 static int check_prlimit_permission(struct task_struct *task)
1485 {
1486         const struct cred *cred = current_cred(), *tcred;
1487
1488         if (current == task)
1489                 return 0;
1490
1491         tcred = __task_cred(task);
1492         if (cred->user->user_ns == tcred->user->user_ns &&
1493             (cred->uid == tcred->euid &&
1494              cred->uid == tcred->suid &&
1495              cred->uid == tcred->uid  &&
1496              cred->gid == tcred->egid &&
1497              cred->gid == tcred->sgid &&
1498              cred->gid == tcred->gid))
1499                 return 0;
1500         if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1501                 return 0;
1502
1503         return -EPERM;
1504 }
1505
1506 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1507                 const struct rlimit64 __user *, new_rlim,
1508                 struct rlimit64 __user *, old_rlim)
1509 {
1510         struct rlimit64 old64, new64;
1511         struct rlimit old, new;
1512         struct task_struct *tsk;
1513         int ret;
1514
1515         if (new_rlim) {
1516                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1517                         return -EFAULT;
1518                 rlim64_to_rlim(&new64, &new);
1519         }
1520
1521         rcu_read_lock();
1522         tsk = pid ? find_task_by_vpid(pid) : current;
1523         if (!tsk) {
1524                 rcu_read_unlock();
1525                 return -ESRCH;
1526         }
1527         ret = check_prlimit_permission(tsk);
1528         if (ret) {
1529                 rcu_read_unlock();
1530                 return ret;
1531         }
1532         get_task_struct(tsk);
1533         rcu_read_unlock();
1534
1535         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1536                         old_rlim ? &old : NULL);
1537
1538         if (!ret && old_rlim) {
1539                 rlim_to_rlim64(&old, &old64);
1540                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1541                         ret = -EFAULT;
1542         }
1543
1544         put_task_struct(tsk);
1545         return ret;
1546 }
1547
1548 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1549 {
1550         struct rlimit new_rlim;
1551
1552         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1553                 return -EFAULT;
1554         return do_prlimit(current, resource, &new_rlim, NULL);
1555 }
1556
1557 /*
1558  * It would make sense to put struct rusage in the task_struct,
1559  * except that would make the task_struct be *really big*.  After
1560  * task_struct gets moved into malloc'ed memory, it would
1561  * make sense to do this.  It will make moving the rest of the information
1562  * a lot simpler!  (Which we're not doing right now because we're not
1563  * measuring them yet).
1564  *
1565  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1566  * races with threads incrementing their own counters.  But since word
1567  * reads are atomic, we either get new values or old values and we don't
1568  * care which for the sums.  We always take the siglock to protect reading
1569  * the c* fields from p->signal from races with exit.c updating those
1570  * fields when reaping, so a sample either gets all the additions of a
1571  * given child after it's reaped, or none so this sample is before reaping.
1572  *
1573  * Locking:
1574  * We need to take the siglock for CHILDEREN, SELF and BOTH
1575  * for  the cases current multithreaded, non-current single threaded
1576  * non-current multithreaded.  Thread traversal is now safe with
1577  * the siglock held.
1578  * Strictly speaking, we donot need to take the siglock if we are current and
1579  * single threaded,  as no one else can take our signal_struct away, no one
1580  * else can  reap the  children to update signal->c* counters, and no one else
1581  * can race with the signal-> fields. If we do not take any lock, the
1582  * signal-> fields could be read out of order while another thread was just
1583  * exiting. So we should  place a read memory barrier when we avoid the lock.
1584  * On the writer side,  write memory barrier is implied in  __exit_signal
1585  * as __exit_signal releases  the siglock spinlock after updating the signal->
1586  * fields. But we don't do this yet to keep things simple.
1587  *
1588  */
1589
1590 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1591 {
1592         r->ru_nvcsw += t->nvcsw;
1593         r->ru_nivcsw += t->nivcsw;
1594         r->ru_minflt += t->min_flt;
1595         r->ru_majflt += t->maj_flt;
1596         r->ru_inblock += task_io_get_inblock(t);
1597         r->ru_oublock += task_io_get_oublock(t);
1598 }
1599
1600 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1601 {
1602         struct task_struct *t;
1603         unsigned long flags;
1604         cputime_t tgutime, tgstime, utime, stime;
1605         unsigned long maxrss = 0;
1606
1607         memset((char *) r, 0, sizeof *r);
1608         utime = stime = 0;
1609
1610         if (who == RUSAGE_THREAD) {
1611                 task_times(current, &utime, &stime);
1612                 accumulate_thread_rusage(p, r);
1613                 maxrss = p->signal->maxrss;
1614                 goto out;
1615         }
1616
1617         if (!lock_task_sighand(p, &flags))
1618                 return;
1619
1620         switch (who) {
1621                 case RUSAGE_BOTH:
1622                 case RUSAGE_CHILDREN:
1623                         utime = p->signal->cutime;
1624                         stime = p->signal->cstime;
1625                         r->ru_nvcsw = p->signal->cnvcsw;
1626                         r->ru_nivcsw = p->signal->cnivcsw;
1627                         r->ru_minflt = p->signal->cmin_flt;
1628                         r->ru_majflt = p->signal->cmaj_flt;
1629                         r->ru_inblock = p->signal->cinblock;
1630                         r->ru_oublock = p->signal->coublock;
1631                         maxrss = p->signal->cmaxrss;
1632
1633                         if (who == RUSAGE_CHILDREN)
1634                                 break;
1635
1636                 case RUSAGE_SELF:
1637                         thread_group_times(p, &tgutime, &tgstime);
1638                         utime += tgutime;
1639                         stime += tgstime;
1640                         r->ru_nvcsw += p->signal->nvcsw;
1641                         r->ru_nivcsw += p->signal->nivcsw;
1642                         r->ru_minflt += p->signal->min_flt;
1643                         r->ru_majflt += p->signal->maj_flt;
1644                         r->ru_inblock += p->signal->inblock;
1645                         r->ru_oublock += p->signal->oublock;
1646                         if (maxrss < p->signal->maxrss)
1647                                 maxrss = p->signal->maxrss;
1648                         t = p;
1649                         do {
1650                                 accumulate_thread_rusage(t, r);
1651                                 t = next_thread(t);
1652                         } while (t != p);
1653                         break;
1654
1655                 default:
1656                         BUG();
1657         }
1658         unlock_task_sighand(p, &flags);
1659
1660 out:
1661         cputime_to_timeval(utime, &r->ru_utime);
1662         cputime_to_timeval(stime, &r->ru_stime);
1663
1664         if (who != RUSAGE_CHILDREN) {
1665                 struct mm_struct *mm = get_task_mm(p);
1666                 if (mm) {
1667                         setmax_mm_hiwater_rss(&maxrss, mm);
1668                         mmput(mm);
1669                 }
1670         }
1671         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1672 }
1673
1674 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1675 {
1676         struct rusage r;
1677         k_getrusage(p, who, &r);
1678         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1679 }
1680
1681 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1682 {
1683         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1684             who != RUSAGE_THREAD)
1685                 return -EINVAL;
1686         return getrusage(current, who, ru);
1687 }
1688
1689 SYSCALL_DEFINE1(umask, int, mask)
1690 {
1691         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1692         return mask;
1693 }
1694
1695 #ifdef CONFIG_CHECKPOINT_RESTORE
1696 static int prctl_set_mm(int opt, unsigned long addr,
1697                         unsigned long arg4, unsigned long arg5)
1698 {
1699         unsigned long rlim = rlimit(RLIMIT_DATA);
1700         unsigned long vm_req_flags;
1701         unsigned long vm_bad_flags;
1702         struct vm_area_struct *vma;
1703         int error = 0;
1704         struct mm_struct *mm = current->mm;
1705
1706         if (arg4 | arg5)
1707                 return -EINVAL;
1708
1709         if (!capable(CAP_SYS_RESOURCE))
1710                 return -EPERM;
1711
1712         if (addr >= TASK_SIZE)
1713                 return -EINVAL;
1714
1715         down_read(&mm->mmap_sem);
1716         vma = find_vma(mm, addr);
1717
1718         if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) {
1719                 /* It must be existing VMA */
1720                 if (!vma || vma->vm_start > addr)
1721                         goto out;
1722         }
1723
1724         error = -EINVAL;
1725         switch (opt) {
1726         case PR_SET_MM_START_CODE:
1727         case PR_SET_MM_END_CODE:
1728                 vm_req_flags = VM_READ | VM_EXEC;
1729                 vm_bad_flags = VM_WRITE | VM_MAYSHARE;
1730
1731                 if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
1732                     (vma->vm_flags & vm_bad_flags))
1733                         goto out;
1734
1735                 if (opt == PR_SET_MM_START_CODE)
1736                         mm->start_code = addr;
1737                 else
1738                         mm->end_code = addr;
1739                 break;
1740
1741         case PR_SET_MM_START_DATA:
1742         case PR_SET_MM_END_DATA:
1743                 vm_req_flags = VM_READ | VM_WRITE;
1744                 vm_bad_flags = VM_EXEC | VM_MAYSHARE;
1745
1746                 if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
1747                     (vma->vm_flags & vm_bad_flags))
1748                         goto out;
1749
1750                 if (opt == PR_SET_MM_START_DATA)
1751                         mm->start_data = addr;
1752                 else
1753                         mm->end_data = addr;
1754                 break;
1755
1756         case PR_SET_MM_START_STACK:
1757
1758 #ifdef CONFIG_STACK_GROWSUP
1759                 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP;
1760 #else
1761                 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN;
1762 #endif
1763                 if ((vma->vm_flags & vm_req_flags) != vm_req_flags)
1764                         goto out;
1765
1766                 mm->start_stack = addr;
1767                 break;
1768
1769         case PR_SET_MM_START_BRK:
1770                 if (addr <= mm->end_data)
1771                         goto out;
1772
1773                 if (rlim < RLIM_INFINITY &&
1774                     (mm->brk - addr) +
1775                     (mm->end_data - mm->start_data) > rlim)
1776                         goto out;
1777
1778                 mm->start_brk = addr;
1779                 break;
1780
1781         case PR_SET_MM_BRK:
1782                 if (addr <= mm->end_data)
1783                         goto out;
1784
1785                 if (rlim < RLIM_INFINITY &&
1786                     (addr - mm->start_brk) +
1787                     (mm->end_data - mm->start_data) > rlim)
1788                         goto out;
1789
1790                 mm->brk = addr;
1791                 break;
1792
1793         default:
1794                 error = -EINVAL;
1795                 goto out;
1796         }
1797
1798         error = 0;
1799
1800 out:
1801         up_read(&mm->mmap_sem);
1802
1803         return error;
1804 }
1805 #else /* CONFIG_CHECKPOINT_RESTORE */
1806 static int prctl_set_mm(int opt, unsigned long addr,
1807                         unsigned long arg4, unsigned long arg5)
1808 {
1809         return -EINVAL;
1810 }
1811 #endif
1812
1813 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1814                 unsigned long, arg4, unsigned long, arg5)
1815 {
1816         struct task_struct *me = current;
1817         unsigned char comm[sizeof(me->comm)];
1818         long error;
1819
1820         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1821         if (error != -ENOSYS)
1822                 return error;
1823
1824         error = 0;
1825         switch (option) {
1826                 case PR_SET_PDEATHSIG:
1827                         if (!valid_signal(arg2)) {
1828                                 error = -EINVAL;
1829                                 break;
1830                         }
1831                         me->pdeath_signal = arg2;
1832                         error = 0;
1833                         break;
1834                 case PR_GET_PDEATHSIG:
1835                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1836                         break;
1837                 case PR_GET_DUMPABLE:
1838                         error = get_dumpable(me->mm);
1839                         break;
1840                 case PR_SET_DUMPABLE:
1841                         if (arg2 < 0 || arg2 > 1) {
1842                                 error = -EINVAL;
1843                                 break;
1844                         }
1845                         set_dumpable(me->mm, arg2);
1846                         error = 0;
1847                         break;
1848
1849                 case PR_SET_UNALIGN:
1850                         error = SET_UNALIGN_CTL(me, arg2);
1851                         break;
1852                 case PR_GET_UNALIGN:
1853                         error = GET_UNALIGN_CTL(me, arg2);
1854                         break;
1855                 case PR_SET_FPEMU:
1856                         error = SET_FPEMU_CTL(me, arg2);
1857                         break;
1858                 case PR_GET_FPEMU:
1859                         error = GET_FPEMU_CTL(me, arg2);
1860                         break;
1861                 case PR_SET_FPEXC:
1862                         error = SET_FPEXC_CTL(me, arg2);
1863                         break;
1864                 case PR_GET_FPEXC:
1865                         error = GET_FPEXC_CTL(me, arg2);
1866                         break;
1867                 case PR_GET_TIMING:
1868                         error = PR_TIMING_STATISTICAL;
1869                         break;
1870                 case PR_SET_TIMING:
1871                         if (arg2 != PR_TIMING_STATISTICAL)
1872                                 error = -EINVAL;
1873                         else
1874                                 error = 0;
1875                         break;
1876
1877                 case PR_SET_NAME:
1878                         comm[sizeof(me->comm)-1] = 0;
1879                         if (strncpy_from_user(comm, (char __user *)arg2,
1880                                               sizeof(me->comm) - 1) < 0)
1881                                 return -EFAULT;
1882                         set_task_comm(me, comm);
1883                         proc_comm_connector(me);
1884                         return 0;
1885                 case PR_GET_NAME:
1886                         get_task_comm(comm, me);
1887                         if (copy_to_user((char __user *)arg2, comm,
1888                                          sizeof(comm)))
1889                                 return -EFAULT;
1890                         return 0;
1891                 case PR_GET_ENDIAN:
1892                         error = GET_ENDIAN(me, arg2);
1893                         break;
1894                 case PR_SET_ENDIAN:
1895                         error = SET_ENDIAN(me, arg2);
1896                         break;
1897
1898                 case PR_GET_SECCOMP:
1899                         error = prctl_get_seccomp();
1900                         break;
1901                 case PR_SET_SECCOMP:
1902                         error = prctl_set_seccomp(arg2);
1903                         break;
1904                 case PR_GET_TSC:
1905                         error = GET_TSC_CTL(arg2);
1906                         break;
1907                 case PR_SET_TSC:
1908                         error = SET_TSC_CTL(arg2);
1909                         break;
1910                 case PR_TASK_PERF_EVENTS_DISABLE:
1911                         error = perf_event_task_disable();
1912                         break;
1913                 case PR_TASK_PERF_EVENTS_ENABLE:
1914                         error = perf_event_task_enable();
1915                         break;
1916                 case PR_GET_TIMERSLACK:
1917                         error = current->timer_slack_ns;
1918                         break;
1919                 case PR_SET_TIMERSLACK:
1920                         if (arg2 <= 0)
1921                                 current->timer_slack_ns =
1922                                         current->default_timer_slack_ns;
1923                         else
1924                                 current->timer_slack_ns = arg2;
1925                         error = 0;
1926                         break;
1927                 case PR_MCE_KILL:
1928                         if (arg4 | arg5)
1929                                 return -EINVAL;
1930                         switch (arg2) {
1931                         case PR_MCE_KILL_CLEAR:
1932                                 if (arg3 != 0)
1933                                         return -EINVAL;
1934                                 current->flags &= ~PF_MCE_PROCESS;
1935                                 break;
1936                         case PR_MCE_KILL_SET:
1937                                 current->flags |= PF_MCE_PROCESS;
1938                                 if (arg3 == PR_MCE_KILL_EARLY)
1939                                         current->flags |= PF_MCE_EARLY;
1940                                 else if (arg3 == PR_MCE_KILL_LATE)
1941                                         current->flags &= ~PF_MCE_EARLY;
1942                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1943                                         current->flags &=
1944                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1945                                 else
1946                                         return -EINVAL;
1947                                 break;
1948                         default:
1949                                 return -EINVAL;
1950                         }
1951                         error = 0;
1952                         break;
1953                 case PR_MCE_KILL_GET:
1954                         if (arg2 | arg3 | arg4 | arg5)
1955                                 return -EINVAL;
1956                         if (current->flags & PF_MCE_PROCESS)
1957                                 error = (current->flags & PF_MCE_EARLY) ?
1958                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1959                         else
1960                                 error = PR_MCE_KILL_DEFAULT;
1961                         break;
1962                 case PR_SET_MM:
1963                         error = prctl_set_mm(arg2, arg3, arg4, arg5);
1964                         break;
1965                 default:
1966                         error = -EINVAL;
1967                         break;
1968         }
1969         return error;
1970 }
1971
1972 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1973                 struct getcpu_cache __user *, unused)
1974 {
1975         int err = 0;
1976         int cpu = raw_smp_processor_id();
1977         if (cpup)
1978                 err |= put_user(cpu, cpup);
1979         if (nodep)
1980                 err |= put_user(cpu_to_node(cpu), nodep);
1981         return err ? -EFAULT : 0;
1982 }
1983
1984 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1985
1986 static void argv_cleanup(struct subprocess_info *info)
1987 {
1988         argv_free(info->argv);
1989 }
1990
1991 /**
1992  * orderly_poweroff - Trigger an orderly system poweroff
1993  * @force: force poweroff if command execution fails
1994  *
1995  * This may be called from any context to trigger a system shutdown.
1996  * If the orderly shutdown fails, it will force an immediate shutdown.
1997  */
1998 int orderly_poweroff(bool force)
1999 {
2000         int argc;
2001         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2002         static char *envp[] = {
2003                 "HOME=/",
2004                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2005                 NULL
2006         };
2007         int ret = -ENOMEM;
2008         struct subprocess_info *info;
2009
2010         if (argv == NULL) {
2011                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2012                        __func__, poweroff_cmd);
2013                 goto out;
2014         }
2015
2016         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
2017         if (info == NULL) {
2018                 argv_free(argv);
2019                 goto out;
2020         }
2021
2022         call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
2023
2024         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
2025
2026   out:
2027         if (ret && force) {
2028                 printk(KERN_WARNING "Failed to start orderly shutdown: "
2029                        "forcing the issue\n");
2030
2031                 /* I guess this should try to kick off some daemon to
2032                    sync and poweroff asap.  Or not even bother syncing
2033                    if we're doing an emergency shutdown? */
2034                 emergency_sync();
2035                 kernel_power_off();
2036         }
2037
2038         return ret;
2039 }
2040 EXPORT_SYMBOL_GPL(orderly_poweroff);