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1 /*
2  *  linux/kernel/sys.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6
7 #include <linux/config.h>
8 #include <linux/module.h>
9 #include <linux/mm.h>
10 #include <linux/utsname.h>
11 #include <linux/mman.h>
12 #include <linux/smp_lock.h>
13 #include <linux/notifier.h>
14 #include <linux/reboot.h>
15 #include <linux/prctl.h>
16 #include <linux/init.h>
17 #include <linux/highuid.h>
18 #include <linux/fs.h>
19 #include <linux/workqueue.h>
20 #include <linux/device.h>
21 #include <linux/key.h>
22 #include <linux/times.h>
23 #include <linux/posix-timers.h>
24 #include <linux/security.h>
25 #include <linux/dcookies.h>
26 #include <linux/suspend.h>
27 #include <linux/tty.h>
28 #include <linux/signal.h>
29
30 #include <linux/compat.h>
31 #include <linux/syscalls.h>
32
33 #include <asm/uaccess.h>
34 #include <asm/io.h>
35 #include <asm/unistd.h>
36
37 #ifndef SET_UNALIGN_CTL
38 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
39 #endif
40 #ifndef GET_UNALIGN_CTL
41 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
42 #endif
43 #ifndef SET_FPEMU_CTL
44 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
45 #endif
46 #ifndef GET_FPEMU_CTL
47 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
48 #endif
49 #ifndef SET_FPEXC_CTL
50 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
51 #endif
52 #ifndef GET_FPEXC_CTL
53 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
54 #endif
55
56 /*
57  * this is where the system-wide overflow UID and GID are defined, for
58  * architectures that now have 32-bit UID/GID but didn't in the past
59  */
60
61 int overflowuid = DEFAULT_OVERFLOWUID;
62 int overflowgid = DEFAULT_OVERFLOWGID;
63
64 #ifdef CONFIG_UID16
65 EXPORT_SYMBOL(overflowuid);
66 EXPORT_SYMBOL(overflowgid);
67 #endif
68
69 /*
70  * the same as above, but for filesystems which can only store a 16-bit
71  * UID and GID. as such, this is needed on all architectures
72  */
73
74 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
75 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
76
77 EXPORT_SYMBOL(fs_overflowuid);
78 EXPORT_SYMBOL(fs_overflowgid);
79
80 /*
81  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
82  */
83
84 int C_A_D = 1;
85 int cad_pid = 1;
86
87 /*
88  *      Notifier list for kernel code which wants to be called
89  *      at shutdown. This is used to stop any idling DMA operations
90  *      and the like. 
91  */
92
93 static struct notifier_block *reboot_notifier_list;
94 static DEFINE_RWLOCK(notifier_lock);
95
96 /**
97  *      notifier_chain_register - Add notifier to a notifier chain
98  *      @list: Pointer to root list pointer
99  *      @n: New entry in notifier chain
100  *
101  *      Adds a notifier to a notifier chain.
102  *
103  *      Currently always returns zero.
104  */
105  
106 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
107 {
108         write_lock(&notifier_lock);
109         while(*list)
110         {
111                 if(n->priority > (*list)->priority)
112                         break;
113                 list= &((*list)->next);
114         }
115         n->next = *list;
116         *list=n;
117         write_unlock(&notifier_lock);
118         return 0;
119 }
120
121 EXPORT_SYMBOL(notifier_chain_register);
122
123 /**
124  *      notifier_chain_unregister - Remove notifier from a notifier chain
125  *      @nl: Pointer to root list pointer
126  *      @n: New entry in notifier chain
127  *
128  *      Removes a notifier from a notifier chain.
129  *
130  *      Returns zero on success, or %-ENOENT on failure.
131  */
132  
133 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
134 {
135         write_lock(&notifier_lock);
136         while((*nl)!=NULL)
137         {
138                 if((*nl)==n)
139                 {
140                         *nl=n->next;
141                         write_unlock(&notifier_lock);
142                         return 0;
143                 }
144                 nl=&((*nl)->next);
145         }
146         write_unlock(&notifier_lock);
147         return -ENOENT;
148 }
149
150 EXPORT_SYMBOL(notifier_chain_unregister);
151
152 /**
153  *      notifier_call_chain - Call functions in a notifier chain
154  *      @n: Pointer to root pointer of notifier chain
155  *      @val: Value passed unmodified to notifier function
156  *      @v: Pointer passed unmodified to notifier function
157  *
158  *      Calls each function in a notifier chain in turn.
159  *
160  *      If the return value of the notifier can be and'd
161  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
162  *      will return immediately, with the return value of
163  *      the notifier function which halted execution.
164  *      Otherwise, the return value is the return value
165  *      of the last notifier function called.
166  */
167  
168 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
169 {
170         int ret=NOTIFY_DONE;
171         struct notifier_block *nb = *n;
172
173         while(nb)
174         {
175                 ret=nb->notifier_call(nb,val,v);
176                 if(ret&NOTIFY_STOP_MASK)
177                 {
178                         return ret;
179                 }
180                 nb=nb->next;
181         }
182         return ret;
183 }
184
185 EXPORT_SYMBOL(notifier_call_chain);
186
187 /**
188  *      register_reboot_notifier - Register function to be called at reboot time
189  *      @nb: Info about notifier function to be called
190  *
191  *      Registers a function with the list of functions
192  *      to be called at reboot time.
193  *
194  *      Currently always returns zero, as notifier_chain_register
195  *      always returns zero.
196  */
197  
198 int register_reboot_notifier(struct notifier_block * nb)
199 {
200         return notifier_chain_register(&reboot_notifier_list, nb);
201 }
202
203 EXPORT_SYMBOL(register_reboot_notifier);
204
205 /**
206  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
207  *      @nb: Hook to be unregistered
208  *
209  *      Unregisters a previously registered reboot
210  *      notifier function.
211  *
212  *      Returns zero on success, or %-ENOENT on failure.
213  */
214  
215 int unregister_reboot_notifier(struct notifier_block * nb)
216 {
217         return notifier_chain_unregister(&reboot_notifier_list, nb);
218 }
219
220 EXPORT_SYMBOL(unregister_reboot_notifier);
221
222 static int set_one_prio(struct task_struct *p, int niceval, int error)
223 {
224         int no_nice;
225
226         if (p->uid != current->euid &&
227                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
228                 error = -EPERM;
229                 goto out;
230         }
231         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
232                 error = -EACCES;
233                 goto out;
234         }
235         no_nice = security_task_setnice(p, niceval);
236         if (no_nice) {
237                 error = no_nice;
238                 goto out;
239         }
240         if (error == -ESRCH)
241                 error = 0;
242         set_user_nice(p, niceval);
243 out:
244         return error;
245 }
246
247 asmlinkage long sys_setpriority(int which, int who, int niceval)
248 {
249         struct task_struct *g, *p;
250         struct user_struct *user;
251         int error = -EINVAL;
252
253         if (which > 2 || which < 0)
254                 goto out;
255
256         /* normalize: avoid signed division (rounding problems) */
257         error = -ESRCH;
258         if (niceval < -20)
259                 niceval = -20;
260         if (niceval > 19)
261                 niceval = 19;
262
263         read_lock(&tasklist_lock);
264         switch (which) {
265                 case PRIO_PROCESS:
266                         if (!who)
267                                 who = current->pid;
268                         p = find_task_by_pid(who);
269                         if (p)
270                                 error = set_one_prio(p, niceval, error);
271                         break;
272                 case PRIO_PGRP:
273                         if (!who)
274                                 who = process_group(current);
275                         do_each_task_pid(who, PIDTYPE_PGID, p) {
276                                 error = set_one_prio(p, niceval, error);
277                         } while_each_task_pid(who, PIDTYPE_PGID, p);
278                         break;
279                 case PRIO_USER:
280                         user = current->user;
281                         if (!who)
282                                 who = current->uid;
283                         else
284                                 if ((who != current->uid) && !(user = find_user(who)))
285                                         goto out_unlock;        /* No processes for this user */
286
287                         do_each_thread(g, p)
288                                 if (p->uid == who)
289                                         error = set_one_prio(p, niceval, error);
290                         while_each_thread(g, p);
291                         if (who != current->uid)
292                                 free_uid(user);         /* For find_user() */
293                         break;
294         }
295 out_unlock:
296         read_unlock(&tasklist_lock);
297 out:
298         return error;
299 }
300
301 /*
302  * Ugh. To avoid negative return values, "getpriority()" will
303  * not return the normal nice-value, but a negated value that
304  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
305  * to stay compatible.
306  */
307 asmlinkage long sys_getpriority(int which, int who)
308 {
309         struct task_struct *g, *p;
310         struct user_struct *user;
311         long niceval, retval = -ESRCH;
312
313         if (which > 2 || which < 0)
314                 return -EINVAL;
315
316         read_lock(&tasklist_lock);
317         switch (which) {
318                 case PRIO_PROCESS:
319                         if (!who)
320                                 who = current->pid;
321                         p = find_task_by_pid(who);
322                         if (p) {
323                                 niceval = 20 - task_nice(p);
324                                 if (niceval > retval)
325                                         retval = niceval;
326                         }
327                         break;
328                 case PRIO_PGRP:
329                         if (!who)
330                                 who = process_group(current);
331                         do_each_task_pid(who, PIDTYPE_PGID, p) {
332                                 niceval = 20 - task_nice(p);
333                                 if (niceval > retval)
334                                         retval = niceval;
335                         } while_each_task_pid(who, PIDTYPE_PGID, p);
336                         break;
337                 case PRIO_USER:
338                         user = current->user;
339                         if (!who)
340                                 who = current->uid;
341                         else
342                                 if ((who != current->uid) && !(user = find_user(who)))
343                                         goto out_unlock;        /* No processes for this user */
344
345                         do_each_thread(g, p)
346                                 if (p->uid == who) {
347                                         niceval = 20 - task_nice(p);
348                                         if (niceval > retval)
349                                                 retval = niceval;
350                                 }
351                         while_each_thread(g, p);
352                         if (who != current->uid)
353                                 free_uid(user);         /* for find_user() */
354                         break;
355         }
356 out_unlock:
357         read_unlock(&tasklist_lock);
358
359         return retval;
360 }
361
362
363 /*
364  * Reboot system call: for obvious reasons only root may call it,
365  * and even root needs to set up some magic numbers in the registers
366  * so that some mistake won't make this reboot the whole machine.
367  * You can also set the meaning of the ctrl-alt-del-key here.
368  *
369  * reboot doesn't sync: do that yourself before calling this.
370  */
371 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
372 {
373         char buffer[256];
374
375         /* We only trust the superuser with rebooting the system. */
376         if (!capable(CAP_SYS_BOOT))
377                 return -EPERM;
378
379         /* For safety, we require "magic" arguments. */
380         if (magic1 != LINUX_REBOOT_MAGIC1 ||
381             (magic2 != LINUX_REBOOT_MAGIC2 &&
382                         magic2 != LINUX_REBOOT_MAGIC2A &&
383                         magic2 != LINUX_REBOOT_MAGIC2B &&
384                         magic2 != LINUX_REBOOT_MAGIC2C))
385                 return -EINVAL;
386
387         lock_kernel();
388         switch (cmd) {
389         case LINUX_REBOOT_CMD_RESTART:
390                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
391                 system_state = SYSTEM_RESTART;
392                 device_shutdown();
393                 printk(KERN_EMERG "Restarting system.\n");
394                 machine_restart(NULL);
395                 break;
396
397         case LINUX_REBOOT_CMD_CAD_ON:
398                 C_A_D = 1;
399                 break;
400
401         case LINUX_REBOOT_CMD_CAD_OFF:
402                 C_A_D = 0;
403                 break;
404
405         case LINUX_REBOOT_CMD_HALT:
406                 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
407                 system_state = SYSTEM_HALT;
408                 device_shutdown();
409                 printk(KERN_EMERG "System halted.\n");
410                 machine_halt();
411                 unlock_kernel();
412                 do_exit(0);
413                 break;
414
415         case LINUX_REBOOT_CMD_POWER_OFF:
416                 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
417                 system_state = SYSTEM_POWER_OFF;
418                 device_shutdown();
419                 printk(KERN_EMERG "Power down.\n");
420                 machine_power_off();
421                 unlock_kernel();
422                 do_exit(0);
423                 break;
424
425         case LINUX_REBOOT_CMD_RESTART2:
426                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
427                         unlock_kernel();
428                         return -EFAULT;
429                 }
430                 buffer[sizeof(buffer) - 1] = '\0';
431
432                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
433                 system_state = SYSTEM_RESTART;
434                 device_shutdown();
435                 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
436                 machine_restart(buffer);
437                 break;
438
439 #ifdef CONFIG_SOFTWARE_SUSPEND
440         case LINUX_REBOOT_CMD_SW_SUSPEND:
441                 {
442                         int ret = software_suspend();
443                         unlock_kernel();
444                         return ret;
445                 }
446 #endif
447
448         default:
449                 unlock_kernel();
450                 return -EINVAL;
451         }
452         unlock_kernel();
453         return 0;
454 }
455
456 static void deferred_cad(void *dummy)
457 {
458         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
459         machine_restart(NULL);
460 }
461
462 /*
463  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
464  * As it's called within an interrupt, it may NOT sync: the only choice
465  * is whether to reboot at once, or just ignore the ctrl-alt-del.
466  */
467 void ctrl_alt_del(void)
468 {
469         static DECLARE_WORK(cad_work, deferred_cad, NULL);
470
471         if (C_A_D)
472                 schedule_work(&cad_work);
473         else
474                 kill_proc(cad_pid, SIGINT, 1);
475 }
476         
477
478 /*
479  * Unprivileged users may change the real gid to the effective gid
480  * or vice versa.  (BSD-style)
481  *
482  * If you set the real gid at all, or set the effective gid to a value not
483  * equal to the real gid, then the saved gid is set to the new effective gid.
484  *
485  * This makes it possible for a setgid program to completely drop its
486  * privileges, which is often a useful assertion to make when you are doing
487  * a security audit over a program.
488  *
489  * The general idea is that a program which uses just setregid() will be
490  * 100% compatible with BSD.  A program which uses just setgid() will be
491  * 100% compatible with POSIX with saved IDs. 
492  *
493  * SMP: There are not races, the GIDs are checked only by filesystem
494  *      operations (as far as semantic preservation is concerned).
495  */
496 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
497 {
498         int old_rgid = current->gid;
499         int old_egid = current->egid;
500         int new_rgid = old_rgid;
501         int new_egid = old_egid;
502         int retval;
503
504         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
505         if (retval)
506                 return retval;
507
508         if (rgid != (gid_t) -1) {
509                 if ((old_rgid == rgid) ||
510                     (current->egid==rgid) ||
511                     capable(CAP_SETGID))
512                         new_rgid = rgid;
513                 else
514                         return -EPERM;
515         }
516         if (egid != (gid_t) -1) {
517                 if ((old_rgid == egid) ||
518                     (current->egid == egid) ||
519                     (current->sgid == egid) ||
520                     capable(CAP_SETGID))
521                         new_egid = egid;
522                 else {
523                         return -EPERM;
524                 }
525         }
526         if (new_egid != old_egid)
527         {
528                 current->mm->dumpable = 0;
529                 smp_wmb();
530         }
531         if (rgid != (gid_t) -1 ||
532             (egid != (gid_t) -1 && egid != old_rgid))
533                 current->sgid = new_egid;
534         current->fsgid = new_egid;
535         current->egid = new_egid;
536         current->gid = new_rgid;
537         key_fsgid_changed(current);
538         return 0;
539 }
540
541 /*
542  * setgid() is implemented like SysV w/ SAVED_IDS 
543  *
544  * SMP: Same implicit races as above.
545  */
546 asmlinkage long sys_setgid(gid_t gid)
547 {
548         int old_egid = current->egid;
549         int retval;
550
551         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
552         if (retval)
553                 return retval;
554
555         if (capable(CAP_SETGID))
556         {
557                 if(old_egid != gid)
558                 {
559                         current->mm->dumpable=0;
560                         smp_wmb();
561                 }
562                 current->gid = current->egid = current->sgid = current->fsgid = gid;
563         }
564         else if ((gid == current->gid) || (gid == current->sgid))
565         {
566                 if(old_egid != gid)
567                 {
568                         current->mm->dumpable=0;
569                         smp_wmb();
570                 }
571                 current->egid = current->fsgid = gid;
572         }
573         else
574                 return -EPERM;
575
576         key_fsgid_changed(current);
577         return 0;
578 }
579   
580 static int set_user(uid_t new_ruid, int dumpclear)
581 {
582         struct user_struct *new_user;
583
584         new_user = alloc_uid(new_ruid);
585         if (!new_user)
586                 return -EAGAIN;
587
588         if (atomic_read(&new_user->processes) >=
589                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
590                         new_user != &root_user) {
591                 free_uid(new_user);
592                 return -EAGAIN;
593         }
594
595         switch_uid(new_user);
596
597         if(dumpclear)
598         {
599                 current->mm->dumpable = 0;
600                 smp_wmb();
601         }
602         current->uid = new_ruid;
603         return 0;
604 }
605
606 /*
607  * Unprivileged users may change the real uid to the effective uid
608  * or vice versa.  (BSD-style)
609  *
610  * If you set the real uid at all, or set the effective uid to a value not
611  * equal to the real uid, then the saved uid is set to the new effective uid.
612  *
613  * This makes it possible for a setuid program to completely drop its
614  * privileges, which is often a useful assertion to make when you are doing
615  * a security audit over a program.
616  *
617  * The general idea is that a program which uses just setreuid() will be
618  * 100% compatible with BSD.  A program which uses just setuid() will be
619  * 100% compatible with POSIX with saved IDs. 
620  */
621 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
622 {
623         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
624         int retval;
625
626         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
627         if (retval)
628                 return retval;
629
630         new_ruid = old_ruid = current->uid;
631         new_euid = old_euid = current->euid;
632         old_suid = current->suid;
633
634         if (ruid != (uid_t) -1) {
635                 new_ruid = ruid;
636                 if ((old_ruid != ruid) &&
637                     (current->euid != ruid) &&
638                     !capable(CAP_SETUID))
639                         return -EPERM;
640         }
641
642         if (euid != (uid_t) -1) {
643                 new_euid = euid;
644                 if ((old_ruid != euid) &&
645                     (current->euid != euid) &&
646                     (current->suid != euid) &&
647                     !capable(CAP_SETUID))
648                         return -EPERM;
649         }
650
651         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
652                 return -EAGAIN;
653
654         if (new_euid != old_euid)
655         {
656                 current->mm->dumpable=0;
657                 smp_wmb();
658         }
659         current->fsuid = current->euid = new_euid;
660         if (ruid != (uid_t) -1 ||
661             (euid != (uid_t) -1 && euid != old_ruid))
662                 current->suid = current->euid;
663         current->fsuid = current->euid;
664
665         key_fsuid_changed(current);
666
667         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
668 }
669
670
671                 
672 /*
673  * setuid() is implemented like SysV with SAVED_IDS 
674  * 
675  * Note that SAVED_ID's is deficient in that a setuid root program
676  * like sendmail, for example, cannot set its uid to be a normal 
677  * user and then switch back, because if you're root, setuid() sets
678  * the saved uid too.  If you don't like this, blame the bright people
679  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
680  * will allow a root program to temporarily drop privileges and be able to
681  * regain them by swapping the real and effective uid.  
682  */
683 asmlinkage long sys_setuid(uid_t uid)
684 {
685         int old_euid = current->euid;
686         int old_ruid, old_suid, new_ruid, new_suid;
687         int retval;
688
689         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
690         if (retval)
691                 return retval;
692
693         old_ruid = new_ruid = current->uid;
694         old_suid = current->suid;
695         new_suid = old_suid;
696         
697         if (capable(CAP_SETUID)) {
698                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
699                         return -EAGAIN;
700                 new_suid = uid;
701         } else if ((uid != current->uid) && (uid != new_suid))
702                 return -EPERM;
703
704         if (old_euid != uid)
705         {
706                 current->mm->dumpable = 0;
707                 smp_wmb();
708         }
709         current->fsuid = current->euid = uid;
710         current->suid = new_suid;
711
712         key_fsuid_changed(current);
713
714         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
715 }
716
717
718 /*
719  * This function implements a generic ability to update ruid, euid,
720  * and suid.  This allows you to implement the 4.4 compatible seteuid().
721  */
722 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
723 {
724         int old_ruid = current->uid;
725         int old_euid = current->euid;
726         int old_suid = current->suid;
727         int retval;
728
729         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
730         if (retval)
731                 return retval;
732
733         if (!capable(CAP_SETUID)) {
734                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
735                     (ruid != current->euid) && (ruid != current->suid))
736                         return -EPERM;
737                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
738                     (euid != current->euid) && (euid != current->suid))
739                         return -EPERM;
740                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
741                     (suid != current->euid) && (suid != current->suid))
742                         return -EPERM;
743         }
744         if (ruid != (uid_t) -1) {
745                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
746                         return -EAGAIN;
747         }
748         if (euid != (uid_t) -1) {
749                 if (euid != current->euid)
750                 {
751                         current->mm->dumpable = 0;
752                         smp_wmb();
753                 }
754                 current->euid = euid;
755         }
756         current->fsuid = current->euid;
757         if (suid != (uid_t) -1)
758                 current->suid = suid;
759
760         key_fsuid_changed(current);
761
762         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
763 }
764
765 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
766 {
767         int retval;
768
769         if (!(retval = put_user(current->uid, ruid)) &&
770             !(retval = put_user(current->euid, euid)))
771                 retval = put_user(current->suid, suid);
772
773         return retval;
774 }
775
776 /*
777  * Same as above, but for rgid, egid, sgid.
778  */
779 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
780 {
781         int retval;
782
783         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
784         if (retval)
785                 return retval;
786
787         if (!capable(CAP_SETGID)) {
788                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
789                     (rgid != current->egid) && (rgid != current->sgid))
790                         return -EPERM;
791                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
792                     (egid != current->egid) && (egid != current->sgid))
793                         return -EPERM;
794                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
795                     (sgid != current->egid) && (sgid != current->sgid))
796                         return -EPERM;
797         }
798         if (egid != (gid_t) -1) {
799                 if (egid != current->egid)
800                 {
801                         current->mm->dumpable = 0;
802                         smp_wmb();
803                 }
804                 current->egid = egid;
805         }
806         current->fsgid = current->egid;
807         if (rgid != (gid_t) -1)
808                 current->gid = rgid;
809         if (sgid != (gid_t) -1)
810                 current->sgid = sgid;
811
812         key_fsgid_changed(current);
813         return 0;
814 }
815
816 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
817 {
818         int retval;
819
820         if (!(retval = put_user(current->gid, rgid)) &&
821             !(retval = put_user(current->egid, egid)))
822                 retval = put_user(current->sgid, sgid);
823
824         return retval;
825 }
826
827
828 /*
829  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
830  * is used for "access()" and for the NFS daemon (letting nfsd stay at
831  * whatever uid it wants to). It normally shadows "euid", except when
832  * explicitly set by setfsuid() or for access..
833  */
834 asmlinkage long sys_setfsuid(uid_t uid)
835 {
836         int old_fsuid;
837
838         old_fsuid = current->fsuid;
839         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
840                 return old_fsuid;
841
842         if (uid == current->uid || uid == current->euid ||
843             uid == current->suid || uid == current->fsuid || 
844             capable(CAP_SETUID))
845         {
846                 if (uid != old_fsuid)
847                 {
848                         current->mm->dumpable = 0;
849                         smp_wmb();
850                 }
851                 current->fsuid = uid;
852         }
853
854         key_fsuid_changed(current);
855
856         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
857
858         return old_fsuid;
859 }
860
861 /*
862  * Samma på svenska..
863  */
864 asmlinkage long sys_setfsgid(gid_t gid)
865 {
866         int old_fsgid;
867
868         old_fsgid = current->fsgid;
869         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
870                 return old_fsgid;
871
872         if (gid == current->gid || gid == current->egid ||
873             gid == current->sgid || gid == current->fsgid || 
874             capable(CAP_SETGID))
875         {
876                 if (gid != old_fsgid)
877                 {
878                         current->mm->dumpable = 0;
879                         smp_wmb();
880                 }
881                 current->fsgid = gid;
882                 key_fsgid_changed(current);
883         }
884         return old_fsgid;
885 }
886
887 asmlinkage long sys_times(struct tms __user * tbuf)
888 {
889         /*
890          *      In the SMP world we might just be unlucky and have one of
891          *      the times increment as we use it. Since the value is an
892          *      atomically safe type this is just fine. Conceptually its
893          *      as if the syscall took an instant longer to occur.
894          */
895         if (tbuf) {
896                 struct tms tmp;
897                 struct task_struct *tsk = current;
898                 struct task_struct *t;
899                 cputime_t utime, stime, cutime, cstime;
900
901                 read_lock(&tasklist_lock);
902                 utime = tsk->signal->utime;
903                 stime = tsk->signal->stime;
904                 t = tsk;
905                 do {
906                         utime = cputime_add(utime, t->utime);
907                         stime = cputime_add(stime, t->stime);
908                         t = next_thread(t);
909                 } while (t != tsk);
910
911                 /*
912                  * While we have tasklist_lock read-locked, no dying thread
913                  * can be updating current->signal->[us]time.  Instead,
914                  * we got their counts included in the live thread loop.
915                  * However, another thread can come in right now and
916                  * do a wait call that updates current->signal->c[us]time.
917                  * To make sure we always see that pair updated atomically,
918                  * we take the siglock around fetching them.
919                  */
920                 spin_lock_irq(&tsk->sighand->siglock);
921                 cutime = tsk->signal->cutime;
922                 cstime = tsk->signal->cstime;
923                 spin_unlock_irq(&tsk->sighand->siglock);
924                 read_unlock(&tasklist_lock);
925
926                 tmp.tms_utime = cputime_to_clock_t(utime);
927                 tmp.tms_stime = cputime_to_clock_t(stime);
928                 tmp.tms_cutime = cputime_to_clock_t(cutime);
929                 tmp.tms_cstime = cputime_to_clock_t(cstime);
930                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
931                         return -EFAULT;
932         }
933         return (long) jiffies_64_to_clock_t(get_jiffies_64());
934 }
935
936 /*
937  * This needs some heavy checking ...
938  * I just haven't the stomach for it. I also don't fully
939  * understand sessions/pgrp etc. Let somebody who does explain it.
940  *
941  * OK, I think I have the protection semantics right.... this is really
942  * only important on a multi-user system anyway, to make sure one user
943  * can't send a signal to a process owned by another.  -TYT, 12/12/91
944  *
945  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
946  * LBT 04.03.94
947  */
948
949 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
950 {
951         struct task_struct *p;
952         int err = -EINVAL;
953
954         if (!pid)
955                 pid = current->pid;
956         if (!pgid)
957                 pgid = pid;
958         if (pgid < 0)
959                 return -EINVAL;
960
961         /* From this point forward we keep holding onto the tasklist lock
962          * so that our parent does not change from under us. -DaveM
963          */
964         write_lock_irq(&tasklist_lock);
965
966         err = -ESRCH;
967         p = find_task_by_pid(pid);
968         if (!p)
969                 goto out;
970
971         err = -EINVAL;
972         if (!thread_group_leader(p))
973                 goto out;
974
975         if (p->parent == current || p->real_parent == current) {
976                 err = -EPERM;
977                 if (p->signal->session != current->signal->session)
978                         goto out;
979                 err = -EACCES;
980                 if (p->did_exec)
981                         goto out;
982         } else {
983                 err = -ESRCH;
984                 if (p != current)
985                         goto out;
986         }
987
988         err = -EPERM;
989         if (p->signal->leader)
990                 goto out;
991
992         if (pgid != pid) {
993                 struct task_struct *p;
994
995                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
996                         if (p->signal->session == current->signal->session)
997                                 goto ok_pgid;
998                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
999                 goto out;
1000         }
1001
1002 ok_pgid:
1003         err = security_task_setpgid(p, pgid);
1004         if (err)
1005                 goto out;
1006
1007         if (process_group(p) != pgid) {
1008                 detach_pid(p, PIDTYPE_PGID);
1009                 p->signal->pgrp = pgid;
1010                 attach_pid(p, PIDTYPE_PGID, pgid);
1011         }
1012
1013         err = 0;
1014 out:
1015         /* All paths lead to here, thus we are safe. -DaveM */
1016         write_unlock_irq(&tasklist_lock);
1017         return err;
1018 }
1019
1020 asmlinkage long sys_getpgid(pid_t pid)
1021 {
1022         if (!pid) {
1023                 return process_group(current);
1024         } else {
1025                 int retval;
1026                 struct task_struct *p;
1027
1028                 read_lock(&tasklist_lock);
1029                 p = find_task_by_pid(pid);
1030
1031                 retval = -ESRCH;
1032                 if (p) {
1033                         retval = security_task_getpgid(p);
1034                         if (!retval)
1035                                 retval = process_group(p);
1036                 }
1037                 read_unlock(&tasklist_lock);
1038                 return retval;
1039         }
1040 }
1041
1042 #ifdef __ARCH_WANT_SYS_GETPGRP
1043
1044 asmlinkage long sys_getpgrp(void)
1045 {
1046         /* SMP - assuming writes are word atomic this is fine */
1047         return process_group(current);
1048 }
1049
1050 #endif
1051
1052 asmlinkage long sys_getsid(pid_t pid)
1053 {
1054         if (!pid) {
1055                 return current->signal->session;
1056         } else {
1057                 int retval;
1058                 struct task_struct *p;
1059
1060                 read_lock(&tasklist_lock);
1061                 p = find_task_by_pid(pid);
1062
1063                 retval = -ESRCH;
1064                 if(p) {
1065                         retval = security_task_getsid(p);
1066                         if (!retval)
1067                                 retval = p->signal->session;
1068                 }
1069                 read_unlock(&tasklist_lock);
1070                 return retval;
1071         }
1072 }
1073
1074 asmlinkage long sys_setsid(void)
1075 {
1076         struct pid *pid;
1077         int err = -EPERM;
1078
1079         if (!thread_group_leader(current))
1080                 return -EINVAL;
1081
1082         down(&tty_sem);
1083         write_lock_irq(&tasklist_lock);
1084
1085         pid = find_pid(PIDTYPE_PGID, current->pid);
1086         if (pid)
1087                 goto out;
1088
1089         current->signal->leader = 1;
1090         __set_special_pids(current->pid, current->pid);
1091         current->signal->tty = NULL;
1092         current->signal->tty_old_pgrp = 0;
1093         err = process_group(current);
1094 out:
1095         write_unlock_irq(&tasklist_lock);
1096         up(&tty_sem);
1097         return err;
1098 }
1099
1100 /*
1101  * Supplementary group IDs
1102  */
1103
1104 /* init to 2 - one for init_task, one to ensure it is never freed */
1105 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1106
1107 struct group_info *groups_alloc(int gidsetsize)
1108 {
1109         struct group_info *group_info;
1110         int nblocks;
1111         int i;
1112
1113         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1114         /* Make sure we always allocate at least one indirect block pointer */
1115         nblocks = nblocks ? : 1;
1116         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1117         if (!group_info)
1118                 return NULL;
1119         group_info->ngroups = gidsetsize;
1120         group_info->nblocks = nblocks;
1121         atomic_set(&group_info->usage, 1);
1122
1123         if (gidsetsize <= NGROUPS_SMALL) {
1124                 group_info->blocks[0] = group_info->small_block;
1125         } else {
1126                 for (i = 0; i < nblocks; i++) {
1127                         gid_t *b;
1128                         b = (void *)__get_free_page(GFP_USER);
1129                         if (!b)
1130                                 goto out_undo_partial_alloc;
1131                         group_info->blocks[i] = b;
1132                 }
1133         }
1134         return group_info;
1135
1136 out_undo_partial_alloc:
1137         while (--i >= 0) {
1138                 free_page((unsigned long)group_info->blocks[i]);
1139         }
1140         kfree(group_info);
1141         return NULL;
1142 }
1143
1144 EXPORT_SYMBOL(groups_alloc);
1145
1146 void groups_free(struct group_info *group_info)
1147 {
1148         if (group_info->blocks[0] != group_info->small_block) {
1149                 int i;
1150                 for (i = 0; i < group_info->nblocks; i++)
1151                         free_page((unsigned long)group_info->blocks[i]);
1152         }
1153         kfree(group_info);
1154 }
1155
1156 EXPORT_SYMBOL(groups_free);
1157
1158 /* export the group_info to a user-space array */
1159 static int groups_to_user(gid_t __user *grouplist,
1160     struct group_info *group_info)
1161 {
1162         int i;
1163         int count = group_info->ngroups;
1164
1165         for (i = 0; i < group_info->nblocks; i++) {
1166                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1167                 int off = i * NGROUPS_PER_BLOCK;
1168                 int len = cp_count * sizeof(*grouplist);
1169
1170                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1171                         return -EFAULT;
1172
1173                 count -= cp_count;
1174         }
1175         return 0;
1176 }
1177
1178 /* fill a group_info from a user-space array - it must be allocated already */
1179 static int groups_from_user(struct group_info *group_info,
1180     gid_t __user *grouplist)
1181  {
1182         int i;
1183         int count = group_info->ngroups;
1184
1185         for (i = 0; i < group_info->nblocks; i++) {
1186                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1187                 int off = i * NGROUPS_PER_BLOCK;
1188                 int len = cp_count * sizeof(*grouplist);
1189
1190                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1191                         return -EFAULT;
1192
1193                 count -= cp_count;
1194         }
1195         return 0;
1196 }
1197
1198 /* a simple Shell sort */
1199 static void groups_sort(struct group_info *group_info)
1200 {
1201         int base, max, stride;
1202         int gidsetsize = group_info->ngroups;
1203
1204         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1205                 ; /* nothing */
1206         stride /= 3;
1207
1208         while (stride) {
1209                 max = gidsetsize - stride;
1210                 for (base = 0; base < max; base++) {
1211                         int left = base;
1212                         int right = left + stride;
1213                         gid_t tmp = GROUP_AT(group_info, right);
1214
1215                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1216                                 GROUP_AT(group_info, right) =
1217                                     GROUP_AT(group_info, left);
1218                                 right = left;
1219                                 left -= stride;
1220                         }
1221                         GROUP_AT(group_info, right) = tmp;
1222                 }
1223                 stride /= 3;
1224         }
1225 }
1226
1227 /* a simple bsearch */
1228 static int groups_search(struct group_info *group_info, gid_t grp)
1229 {
1230         int left, right;
1231
1232         if (!group_info)
1233                 return 0;
1234
1235         left = 0;
1236         right = group_info->ngroups;
1237         while (left < right) {
1238                 int mid = (left+right)/2;
1239                 int cmp = grp - GROUP_AT(group_info, mid);
1240                 if (cmp > 0)
1241                         left = mid + 1;
1242                 else if (cmp < 0)
1243                         right = mid;
1244                 else
1245                         return 1;
1246         }
1247         return 0;
1248 }
1249
1250 /* validate and set current->group_info */
1251 int set_current_groups(struct group_info *group_info)
1252 {
1253         int retval;
1254         struct group_info *old_info;
1255
1256         retval = security_task_setgroups(group_info);
1257         if (retval)
1258                 return retval;
1259
1260         groups_sort(group_info);
1261         get_group_info(group_info);
1262
1263         task_lock(current);
1264         old_info = current->group_info;
1265         current->group_info = group_info;
1266         task_unlock(current);
1267
1268         put_group_info(old_info);
1269
1270         return 0;
1271 }
1272
1273 EXPORT_SYMBOL(set_current_groups);
1274
1275 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1276 {
1277         int i = 0;
1278
1279         /*
1280          *      SMP: Nobody else can change our grouplist. Thus we are
1281          *      safe.
1282          */
1283
1284         if (gidsetsize < 0)
1285                 return -EINVAL;
1286
1287         /* no need to grab task_lock here; it cannot change */
1288         get_group_info(current->group_info);
1289         i = current->group_info->ngroups;
1290         if (gidsetsize) {
1291                 if (i > gidsetsize) {
1292                         i = -EINVAL;
1293                         goto out;
1294                 }
1295                 if (groups_to_user(grouplist, current->group_info)) {
1296                         i = -EFAULT;
1297                         goto out;
1298                 }
1299         }
1300 out:
1301         put_group_info(current->group_info);
1302         return i;
1303 }
1304
1305 /*
1306  *      SMP: Our groups are copy-on-write. We can set them safely
1307  *      without another task interfering.
1308  */
1309  
1310 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1311 {
1312         struct group_info *group_info;
1313         int retval;
1314
1315         if (!capable(CAP_SETGID))
1316                 return -EPERM;
1317         if ((unsigned)gidsetsize > NGROUPS_MAX)
1318                 return -EINVAL;
1319
1320         group_info = groups_alloc(gidsetsize);
1321         if (!group_info)
1322                 return -ENOMEM;
1323         retval = groups_from_user(group_info, grouplist);
1324         if (retval) {
1325                 put_group_info(group_info);
1326                 return retval;
1327         }
1328
1329         retval = set_current_groups(group_info);
1330         put_group_info(group_info);
1331
1332         return retval;
1333 }
1334
1335 /*
1336  * Check whether we're fsgid/egid or in the supplemental group..
1337  */
1338 int in_group_p(gid_t grp)
1339 {
1340         int retval = 1;
1341         if (grp != current->fsgid) {
1342                 get_group_info(current->group_info);
1343                 retval = groups_search(current->group_info, grp);
1344                 put_group_info(current->group_info);
1345         }
1346         return retval;
1347 }
1348
1349 EXPORT_SYMBOL(in_group_p);
1350
1351 int in_egroup_p(gid_t grp)
1352 {
1353         int retval = 1;
1354         if (grp != current->egid) {
1355                 get_group_info(current->group_info);
1356                 retval = groups_search(current->group_info, grp);
1357                 put_group_info(current->group_info);
1358         }
1359         return retval;
1360 }
1361
1362 EXPORT_SYMBOL(in_egroup_p);
1363
1364 DECLARE_RWSEM(uts_sem);
1365
1366 EXPORT_SYMBOL(uts_sem);
1367
1368 asmlinkage long sys_newuname(struct new_utsname __user * name)
1369 {
1370         int errno = 0;
1371
1372         down_read(&uts_sem);
1373         if (copy_to_user(name,&system_utsname,sizeof *name))
1374                 errno = -EFAULT;
1375         up_read(&uts_sem);
1376         return errno;
1377 }
1378
1379 asmlinkage long sys_sethostname(char __user *name, int len)
1380 {
1381         int errno;
1382         char tmp[__NEW_UTS_LEN];
1383
1384         if (!capable(CAP_SYS_ADMIN))
1385                 return -EPERM;
1386         if (len < 0 || len > __NEW_UTS_LEN)
1387                 return -EINVAL;
1388         down_write(&uts_sem);
1389         errno = -EFAULT;
1390         if (!copy_from_user(tmp, name, len)) {
1391                 memcpy(system_utsname.nodename, tmp, len);
1392                 system_utsname.nodename[len] = 0;
1393                 errno = 0;
1394         }
1395         up_write(&uts_sem);
1396         return errno;
1397 }
1398
1399 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1400
1401 asmlinkage long sys_gethostname(char __user *name, int len)
1402 {
1403         int i, errno;
1404
1405         if (len < 0)
1406                 return -EINVAL;
1407         down_read(&uts_sem);
1408         i = 1 + strlen(system_utsname.nodename);
1409         if (i > len)
1410                 i = len;
1411         errno = 0;
1412         if (copy_to_user(name, system_utsname.nodename, i))
1413                 errno = -EFAULT;
1414         up_read(&uts_sem);
1415         return errno;
1416 }
1417
1418 #endif
1419
1420 /*
1421  * Only setdomainname; getdomainname can be implemented by calling
1422  * uname()
1423  */
1424 asmlinkage long sys_setdomainname(char __user *name, int len)
1425 {
1426         int errno;
1427         char tmp[__NEW_UTS_LEN];
1428
1429         if (!capable(CAP_SYS_ADMIN))
1430                 return -EPERM;
1431         if (len < 0 || len > __NEW_UTS_LEN)
1432                 return -EINVAL;
1433
1434         down_write(&uts_sem);
1435         errno = -EFAULT;
1436         if (!copy_from_user(tmp, name, len)) {
1437                 memcpy(system_utsname.domainname, tmp, len);
1438                 system_utsname.domainname[len] = 0;
1439                 errno = 0;
1440         }
1441         up_write(&uts_sem);
1442         return errno;
1443 }
1444
1445 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1446 {
1447         if (resource >= RLIM_NLIMITS)
1448                 return -EINVAL;
1449         else {
1450                 struct rlimit value;
1451                 task_lock(current->group_leader);
1452                 value = current->signal->rlim[resource];
1453                 task_unlock(current->group_leader);
1454                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1455         }
1456 }
1457
1458 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1459
1460 /*
1461  *      Back compatibility for getrlimit. Needed for some apps.
1462  */
1463  
1464 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1465 {
1466         struct rlimit x;
1467         if (resource >= RLIM_NLIMITS)
1468                 return -EINVAL;
1469
1470         task_lock(current->group_leader);
1471         x = current->signal->rlim[resource];
1472         task_unlock(current->group_leader);
1473         if(x.rlim_cur > 0x7FFFFFFF)
1474                 x.rlim_cur = 0x7FFFFFFF;
1475         if(x.rlim_max > 0x7FFFFFFF)
1476                 x.rlim_max = 0x7FFFFFFF;
1477         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1478 }
1479
1480 #endif
1481
1482 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1483 {
1484         struct rlimit new_rlim, *old_rlim;
1485         int retval;
1486
1487         if (resource >= RLIM_NLIMITS)
1488                 return -EINVAL;
1489         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1490                 return -EFAULT;
1491        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1492                return -EINVAL;
1493         old_rlim = current->signal->rlim + resource;
1494         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1495             !capable(CAP_SYS_RESOURCE))
1496                 return -EPERM;
1497         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1498                         return -EPERM;
1499
1500         retval = security_task_setrlimit(resource, &new_rlim);
1501         if (retval)
1502                 return retval;
1503
1504         task_lock(current->group_leader);
1505         *old_rlim = new_rlim;
1506         task_unlock(current->group_leader);
1507
1508         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1509             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1510              new_rlim.rlim_cur <= cputime_to_secs(
1511                      current->signal->it_prof_expires))) {
1512                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1513                 read_lock(&tasklist_lock);
1514                 spin_lock_irq(&current->sighand->siglock);
1515                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1516                                       &cputime, NULL);
1517                 spin_unlock_irq(&current->sighand->siglock);
1518                 read_unlock(&tasklist_lock);
1519         }
1520
1521         return 0;
1522 }
1523
1524 /*
1525  * It would make sense to put struct rusage in the task_struct,
1526  * except that would make the task_struct be *really big*.  After
1527  * task_struct gets moved into malloc'ed memory, it would
1528  * make sense to do this.  It will make moving the rest of the information
1529  * a lot simpler!  (Which we're not doing right now because we're not
1530  * measuring them yet).
1531  *
1532  * This expects to be called with tasklist_lock read-locked or better,
1533  * and the siglock not locked.  It may momentarily take the siglock.
1534  *
1535  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1536  * races with threads incrementing their own counters.  But since word
1537  * reads are atomic, we either get new values or old values and we don't
1538  * care which for the sums.  We always take the siglock to protect reading
1539  * the c* fields from p->signal from races with exit.c updating those
1540  * fields when reaping, so a sample either gets all the additions of a
1541  * given child after it's reaped, or none so this sample is before reaping.
1542  */
1543
1544 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1545 {
1546         struct task_struct *t;
1547         unsigned long flags;
1548         cputime_t utime, stime;
1549
1550         memset((char *) r, 0, sizeof *r);
1551
1552         if (unlikely(!p->signal))
1553                 return;
1554
1555         switch (who) {
1556                 case RUSAGE_CHILDREN:
1557                         spin_lock_irqsave(&p->sighand->siglock, flags);
1558                         utime = p->signal->cutime;
1559                         stime = p->signal->cstime;
1560                         r->ru_nvcsw = p->signal->cnvcsw;
1561                         r->ru_nivcsw = p->signal->cnivcsw;
1562                         r->ru_minflt = p->signal->cmin_flt;
1563                         r->ru_majflt = p->signal->cmaj_flt;
1564                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1565                         cputime_to_timeval(utime, &r->ru_utime);
1566                         cputime_to_timeval(stime, &r->ru_stime);
1567                         break;
1568                 case RUSAGE_SELF:
1569                         spin_lock_irqsave(&p->sighand->siglock, flags);
1570                         utime = stime = cputime_zero;
1571                         goto sum_group;
1572                 case RUSAGE_BOTH:
1573                         spin_lock_irqsave(&p->sighand->siglock, flags);
1574                         utime = p->signal->cutime;
1575                         stime = p->signal->cstime;
1576                         r->ru_nvcsw = p->signal->cnvcsw;
1577                         r->ru_nivcsw = p->signal->cnivcsw;
1578                         r->ru_minflt = p->signal->cmin_flt;
1579                         r->ru_majflt = p->signal->cmaj_flt;
1580                 sum_group:
1581                         utime = cputime_add(utime, p->signal->utime);
1582                         stime = cputime_add(stime, p->signal->stime);
1583                         r->ru_nvcsw += p->signal->nvcsw;
1584                         r->ru_nivcsw += p->signal->nivcsw;
1585                         r->ru_minflt += p->signal->min_flt;
1586                         r->ru_majflt += p->signal->maj_flt;
1587                         t = p;
1588                         do {
1589                                 utime = cputime_add(utime, t->utime);
1590                                 stime = cputime_add(stime, t->stime);
1591                                 r->ru_nvcsw += t->nvcsw;
1592                                 r->ru_nivcsw += t->nivcsw;
1593                                 r->ru_minflt += t->min_flt;
1594                                 r->ru_majflt += t->maj_flt;
1595                                 t = next_thread(t);
1596                         } while (t != p);
1597                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1598                         cputime_to_timeval(utime, &r->ru_utime);
1599                         cputime_to_timeval(stime, &r->ru_stime);
1600                         break;
1601                 default:
1602                         BUG();
1603         }
1604 }
1605
1606 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1607 {
1608         struct rusage r;
1609         read_lock(&tasklist_lock);
1610         k_getrusage(p, who, &r);
1611         read_unlock(&tasklist_lock);
1612         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1613 }
1614
1615 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1616 {
1617         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1618                 return -EINVAL;
1619         return getrusage(current, who, ru);
1620 }
1621
1622 asmlinkage long sys_umask(int mask)
1623 {
1624         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1625         return mask;
1626 }
1627     
1628 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1629                           unsigned long arg4, unsigned long arg5)
1630 {
1631         long error;
1632         int sig;
1633
1634         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1635         if (error)
1636                 return error;
1637
1638         switch (option) {
1639                 case PR_SET_PDEATHSIG:
1640                         sig = arg2;
1641                         if (!valid_signal(sig)) {
1642                                 error = -EINVAL;
1643                                 break;
1644                         }
1645                         current->pdeath_signal = sig;
1646                         break;
1647                 case PR_GET_PDEATHSIG:
1648                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1649                         break;
1650                 case PR_GET_DUMPABLE:
1651                         if (current->mm->dumpable)
1652                                 error = 1;
1653                         break;
1654                 case PR_SET_DUMPABLE:
1655                         if (arg2 != 0 && arg2 != 1) {
1656                                 error = -EINVAL;
1657                                 break;
1658                         }
1659                         current->mm->dumpable = arg2;
1660                         break;
1661
1662                 case PR_SET_UNALIGN:
1663                         error = SET_UNALIGN_CTL(current, arg2);
1664                         break;
1665                 case PR_GET_UNALIGN:
1666                         error = GET_UNALIGN_CTL(current, arg2);
1667                         break;
1668                 case PR_SET_FPEMU:
1669                         error = SET_FPEMU_CTL(current, arg2);
1670                         break;
1671                 case PR_GET_FPEMU:
1672                         error = GET_FPEMU_CTL(current, arg2);
1673                         break;
1674                 case PR_SET_FPEXC:
1675                         error = SET_FPEXC_CTL(current, arg2);
1676                         break;
1677                 case PR_GET_FPEXC:
1678                         error = GET_FPEXC_CTL(current, arg2);
1679                         break;
1680                 case PR_GET_TIMING:
1681                         error = PR_TIMING_STATISTICAL;
1682                         break;
1683                 case PR_SET_TIMING:
1684                         if (arg2 == PR_TIMING_STATISTICAL)
1685                                 error = 0;
1686                         else
1687                                 error = -EINVAL;
1688                         break;
1689
1690                 case PR_GET_KEEPCAPS:
1691                         if (current->keep_capabilities)
1692                                 error = 1;
1693                         break;
1694                 case PR_SET_KEEPCAPS:
1695                         if (arg2 != 0 && arg2 != 1) {
1696                                 error = -EINVAL;
1697                                 break;
1698                         }
1699                         current->keep_capabilities = arg2;
1700                         break;
1701                 case PR_SET_NAME: {
1702                         struct task_struct *me = current;
1703                         unsigned char ncomm[sizeof(me->comm)];
1704
1705                         ncomm[sizeof(me->comm)-1] = 0;
1706                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1707                                                 sizeof(me->comm)-1) < 0)
1708                                 return -EFAULT;
1709                         set_task_comm(me, ncomm);
1710                         return 0;
1711                 }
1712                 case PR_GET_NAME: {
1713                         struct task_struct *me = current;
1714                         unsigned char tcomm[sizeof(me->comm)];
1715
1716                         get_task_comm(tcomm, me);
1717                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1718                                 return -EFAULT;
1719                         return 0;
1720                 }
1721                 default:
1722                         error = -EINVAL;
1723                         break;
1724         }
1725         return error;
1726 }