3e332131000ead377e3424306805f0fa57792fec
[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/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/kernel.h>
20 #include <linux/kexec.h>
21 #include <linux/workqueue.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
33 #include <linux/compat.h>
34 #include <linux/syscalls.h>
35
36 #include <asm/uaccess.h>
37 #include <asm/io.h>
38 #include <asm/unistd.h>
39
40 #ifndef SET_UNALIGN_CTL
41 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
42 #endif
43 #ifndef GET_UNALIGN_CTL
44 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
45 #endif
46 #ifndef SET_FPEMU_CTL
47 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
48 #endif
49 #ifndef GET_FPEMU_CTL
50 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
51 #endif
52 #ifndef SET_FPEXC_CTL
53 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
54 #endif
55 #ifndef GET_FPEXC_CTL
56 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
57 #endif
58
59 /*
60  * this is where the system-wide overflow UID and GID are defined, for
61  * architectures that now have 32-bit UID/GID but didn't in the past
62  */
63
64 int overflowuid = DEFAULT_OVERFLOWUID;
65 int overflowgid = DEFAULT_OVERFLOWGID;
66
67 #ifdef CONFIG_UID16
68 EXPORT_SYMBOL(overflowuid);
69 EXPORT_SYMBOL(overflowgid);
70 #endif
71
72 /*
73  * the same as above, but for filesystems which can only store a 16-bit
74  * UID and GID. as such, this is needed on all architectures
75  */
76
77 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
78 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
79
80 EXPORT_SYMBOL(fs_overflowuid);
81 EXPORT_SYMBOL(fs_overflowgid);
82
83 /*
84  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
85  */
86
87 int C_A_D = 1;
88 int cad_pid = 1;
89
90 /*
91  *      Notifier list for kernel code which wants to be called
92  *      at shutdown. This is used to stop any idling DMA operations
93  *      and the like. 
94  */
95
96 static struct notifier_block *reboot_notifier_list;
97 static DEFINE_RWLOCK(notifier_lock);
98
99 /**
100  *      notifier_chain_register - Add notifier to a notifier chain
101  *      @list: Pointer to root list pointer
102  *      @n: New entry in notifier chain
103  *
104  *      Adds a notifier to a notifier chain.
105  *
106  *      Currently always returns zero.
107  */
108  
109 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
110 {
111         write_lock(&notifier_lock);
112         while(*list)
113         {
114                 if(n->priority > (*list)->priority)
115                         break;
116                 list= &((*list)->next);
117         }
118         n->next = *list;
119         *list=n;
120         write_unlock(&notifier_lock);
121         return 0;
122 }
123
124 EXPORT_SYMBOL(notifier_chain_register);
125
126 /**
127  *      notifier_chain_unregister - Remove notifier from a notifier chain
128  *      @nl: Pointer to root list pointer
129  *      @n: New entry in notifier chain
130  *
131  *      Removes a notifier from a notifier chain.
132  *
133  *      Returns zero on success, or %-ENOENT on failure.
134  */
135  
136 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
137 {
138         write_lock(&notifier_lock);
139         while((*nl)!=NULL)
140         {
141                 if((*nl)==n)
142                 {
143                         *nl=n->next;
144                         write_unlock(&notifier_lock);
145                         return 0;
146                 }
147                 nl=&((*nl)->next);
148         }
149         write_unlock(&notifier_lock);
150         return -ENOENT;
151 }
152
153 EXPORT_SYMBOL(notifier_chain_unregister);
154
155 /**
156  *      notifier_call_chain - Call functions in a notifier chain
157  *      @n: Pointer to root pointer of notifier chain
158  *      @val: Value passed unmodified to notifier function
159  *      @v: Pointer passed unmodified to notifier function
160  *
161  *      Calls each function in a notifier chain in turn.
162  *
163  *      If the return value of the notifier can be and'd
164  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
165  *      will return immediately, with the return value of
166  *      the notifier function which halted execution.
167  *      Otherwise, the return value is the return value
168  *      of the last notifier function called.
169  */
170  
171 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
172 {
173         int ret=NOTIFY_DONE;
174         struct notifier_block *nb = *n;
175
176         while(nb)
177         {
178                 ret=nb->notifier_call(nb,val,v);
179                 if(ret&NOTIFY_STOP_MASK)
180                 {
181                         return ret;
182                 }
183                 nb=nb->next;
184         }
185         return ret;
186 }
187
188 EXPORT_SYMBOL(notifier_call_chain);
189
190 /**
191  *      register_reboot_notifier - Register function to be called at reboot time
192  *      @nb: Info about notifier function to be called
193  *
194  *      Registers a function with the list of functions
195  *      to be called at reboot time.
196  *
197  *      Currently always returns zero, as notifier_chain_register
198  *      always returns zero.
199  */
200  
201 int register_reboot_notifier(struct notifier_block * nb)
202 {
203         return notifier_chain_register(&reboot_notifier_list, nb);
204 }
205
206 EXPORT_SYMBOL(register_reboot_notifier);
207
208 /**
209  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
210  *      @nb: Hook to be unregistered
211  *
212  *      Unregisters a previously registered reboot
213  *      notifier function.
214  *
215  *      Returns zero on success, or %-ENOENT on failure.
216  */
217  
218 int unregister_reboot_notifier(struct notifier_block * nb)
219 {
220         return notifier_chain_unregister(&reboot_notifier_list, nb);
221 }
222
223 EXPORT_SYMBOL(unregister_reboot_notifier);
224
225 static int set_one_prio(struct task_struct *p, int niceval, int error)
226 {
227         int no_nice;
228
229         if (p->uid != current->euid &&
230                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
231                 error = -EPERM;
232                 goto out;
233         }
234         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
235                 error = -EACCES;
236                 goto out;
237         }
238         no_nice = security_task_setnice(p, niceval);
239         if (no_nice) {
240                 error = no_nice;
241                 goto out;
242         }
243         if (error == -ESRCH)
244                 error = 0;
245         set_user_nice(p, niceval);
246 out:
247         return error;
248 }
249
250 asmlinkage long sys_setpriority(int which, int who, int niceval)
251 {
252         struct task_struct *g, *p;
253         struct user_struct *user;
254         int error = -EINVAL;
255
256         if (which > 2 || which < 0)
257                 goto out;
258
259         /* normalize: avoid signed division (rounding problems) */
260         error = -ESRCH;
261         if (niceval < -20)
262                 niceval = -20;
263         if (niceval > 19)
264                 niceval = 19;
265
266         read_lock(&tasklist_lock);
267         switch (which) {
268                 case PRIO_PROCESS:
269                         if (!who)
270                                 who = current->pid;
271                         p = find_task_by_pid(who);
272                         if (p)
273                                 error = set_one_prio(p, niceval, error);
274                         break;
275                 case PRIO_PGRP:
276                         if (!who)
277                                 who = process_group(current);
278                         do_each_task_pid(who, PIDTYPE_PGID, p) {
279                                 error = set_one_prio(p, niceval, error);
280                         } while_each_task_pid(who, PIDTYPE_PGID, p);
281                         break;
282                 case PRIO_USER:
283                         user = current->user;
284                         if (!who)
285                                 who = current->uid;
286                         else
287                                 if ((who != current->uid) && !(user = find_user(who)))
288                                         goto out_unlock;        /* No processes for this user */
289
290                         do_each_thread(g, p)
291                                 if (p->uid == who)
292                                         error = set_one_prio(p, niceval, error);
293                         while_each_thread(g, p);
294                         if (who != current->uid)
295                                 free_uid(user);         /* For find_user() */
296                         break;
297         }
298 out_unlock:
299         read_unlock(&tasklist_lock);
300 out:
301         return error;
302 }
303
304 /*
305  * Ugh. To avoid negative return values, "getpriority()" will
306  * not return the normal nice-value, but a negated value that
307  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
308  * to stay compatible.
309  */
310 asmlinkage long sys_getpriority(int which, int who)
311 {
312         struct task_struct *g, *p;
313         struct user_struct *user;
314         long niceval, retval = -ESRCH;
315
316         if (which > 2 || which < 0)
317                 return -EINVAL;
318
319         read_lock(&tasklist_lock);
320         switch (which) {
321                 case PRIO_PROCESS:
322                         if (!who)
323                                 who = current->pid;
324                         p = find_task_by_pid(who);
325                         if (p) {
326                                 niceval = 20 - task_nice(p);
327                                 if (niceval > retval)
328                                         retval = niceval;
329                         }
330                         break;
331                 case PRIO_PGRP:
332                         if (!who)
333                                 who = process_group(current);
334                         do_each_task_pid(who, PIDTYPE_PGID, p) {
335                                 niceval = 20 - task_nice(p);
336                                 if (niceval > retval)
337                                         retval = niceval;
338                         } while_each_task_pid(who, PIDTYPE_PGID, p);
339                         break;
340                 case PRIO_USER:
341                         user = current->user;
342                         if (!who)
343                                 who = current->uid;
344                         else
345                                 if ((who != current->uid) && !(user = find_user(who)))
346                                         goto out_unlock;        /* No processes for this user */
347
348                         do_each_thread(g, p)
349                                 if (p->uid == who) {
350                                         niceval = 20 - task_nice(p);
351                                         if (niceval > retval)
352                                                 retval = niceval;
353                                 }
354                         while_each_thread(g, p);
355                         if (who != current->uid)
356                                 free_uid(user);         /* for find_user() */
357                         break;
358         }
359 out_unlock:
360         read_unlock(&tasklist_lock);
361
362         return retval;
363 }
364
365 /**
366  *      emergency_restart - reboot the system
367  *
368  *      Without shutting down any hardware or taking any locks
369  *      reboot the system.  This is called when we know we are in
370  *      trouble so this is our best effort to reboot.  This is
371  *      safe to call in interrupt context.
372  */
373 void emergency_restart(void)
374 {
375         machine_emergency_restart();
376 }
377 EXPORT_SYMBOL_GPL(emergency_restart);
378
379 void kernel_restart_prepare(char *cmd)
380 {
381         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
382         system_state = SYSTEM_RESTART;
383         device_shutdown();
384 }
385
386 /**
387  *      kernel_restart - reboot the system
388  *      @cmd: pointer to buffer containing command to execute for restart
389  *              or NULL
390  *
391  *      Shutdown everything and perform a clean reboot.
392  *      This is not safe to call in interrupt context.
393  */
394 void kernel_restart(char *cmd)
395 {
396         kernel_restart_prepare(cmd);
397         if (!cmd) {
398                 printk(KERN_EMERG "Restarting system.\n");
399         } else {
400                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
401         }
402         printk(".\n");
403         machine_restart(cmd);
404 }
405 EXPORT_SYMBOL_GPL(kernel_restart);
406
407 /**
408  *      kernel_kexec - reboot the system
409  *
410  *      Move into place and start executing a preloaded standalone
411  *      executable.  If nothing was preloaded return an error.
412  */
413 void kernel_kexec(void)
414 {
415 #ifdef CONFIG_KEXEC
416         struct kimage *image;
417         image = xchg(&kexec_image, 0);
418         if (!image) {
419                 return;
420         }
421         kernel_restart_prepare(NULL);
422         printk(KERN_EMERG "Starting new kernel\n");
423         machine_shutdown();
424         machine_kexec(image);
425 #endif
426 }
427 EXPORT_SYMBOL_GPL(kernel_kexec);
428
429 /**
430  *      kernel_halt - halt the system
431  *
432  *      Shutdown everything and perform a clean system halt.
433  */
434 void kernel_halt_prepare(void)
435 {
436         notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
437         system_state = SYSTEM_HALT;
438         device_shutdown();
439 }
440 void kernel_halt(void)
441 {
442         kernel_halt_prepare();
443         printk(KERN_EMERG "System halted.\n");
444         machine_halt();
445 }
446 EXPORT_SYMBOL_GPL(kernel_halt);
447
448 /**
449  *      kernel_power_off - power_off the system
450  *
451  *      Shutdown everything and perform a clean system power_off.
452  */
453 void kernel_power_off_prepare(void)
454 {
455         notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
456         system_state = SYSTEM_POWER_OFF;
457         device_shutdown();
458 }
459 void kernel_power_off(void)
460 {
461         kernel_power_off_prepare();
462         printk(KERN_EMERG "Power down.\n");
463         machine_power_off();
464 }
465 EXPORT_SYMBOL_GPL(kernel_power_off);
466
467 /*
468  * Reboot system call: for obvious reasons only root may call it,
469  * and even root needs to set up some magic numbers in the registers
470  * so that some mistake won't make this reboot the whole machine.
471  * You can also set the meaning of the ctrl-alt-del-key here.
472  *
473  * reboot doesn't sync: do that yourself before calling this.
474  */
475 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
476 {
477         char buffer[256];
478
479         /* We only trust the superuser with rebooting the system. */
480         if (!capable(CAP_SYS_BOOT))
481                 return -EPERM;
482
483         /* For safety, we require "magic" arguments. */
484         if (magic1 != LINUX_REBOOT_MAGIC1 ||
485             (magic2 != LINUX_REBOOT_MAGIC2 &&
486                         magic2 != LINUX_REBOOT_MAGIC2A &&
487                         magic2 != LINUX_REBOOT_MAGIC2B &&
488                         magic2 != LINUX_REBOOT_MAGIC2C))
489                 return -EINVAL;
490
491         lock_kernel();
492         switch (cmd) {
493         case LINUX_REBOOT_CMD_RESTART:
494                 kernel_restart(NULL);
495                 break;
496
497         case LINUX_REBOOT_CMD_CAD_ON:
498                 C_A_D = 1;
499                 break;
500
501         case LINUX_REBOOT_CMD_CAD_OFF:
502                 C_A_D = 0;
503                 break;
504
505         case LINUX_REBOOT_CMD_HALT:
506                 kernel_halt();
507                 unlock_kernel();
508                 do_exit(0);
509                 break;
510
511         case LINUX_REBOOT_CMD_POWER_OFF:
512                 kernel_power_off();
513                 unlock_kernel();
514                 do_exit(0);
515                 break;
516
517         case LINUX_REBOOT_CMD_RESTART2:
518                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
519                         unlock_kernel();
520                         return -EFAULT;
521                 }
522                 buffer[sizeof(buffer) - 1] = '\0';
523
524                 kernel_restart(buffer);
525                 break;
526
527         case LINUX_REBOOT_CMD_KEXEC:
528                 kernel_kexec();
529                 unlock_kernel();
530                 return -EINVAL;
531
532 #ifdef CONFIG_SOFTWARE_SUSPEND
533         case LINUX_REBOOT_CMD_SW_SUSPEND:
534                 {
535                         int ret = software_suspend();
536                         unlock_kernel();
537                         return ret;
538                 }
539 #endif
540
541         default:
542                 unlock_kernel();
543                 return -EINVAL;
544         }
545         unlock_kernel();
546         return 0;
547 }
548
549 static void deferred_cad(void *dummy)
550 {
551         kernel_restart(NULL);
552 }
553
554 /*
555  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
556  * As it's called within an interrupt, it may NOT sync: the only choice
557  * is whether to reboot at once, or just ignore the ctrl-alt-del.
558  */
559 void ctrl_alt_del(void)
560 {
561         static DECLARE_WORK(cad_work, deferred_cad, NULL);
562
563         if (C_A_D)
564                 schedule_work(&cad_work);
565         else
566                 kill_proc(cad_pid, SIGINT, 1);
567 }
568         
569
570 /*
571  * Unprivileged users may change the real gid to the effective gid
572  * or vice versa.  (BSD-style)
573  *
574  * If you set the real gid at all, or set the effective gid to a value not
575  * equal to the real gid, then the saved gid is set to the new effective gid.
576  *
577  * This makes it possible for a setgid program to completely drop its
578  * privileges, which is often a useful assertion to make when you are doing
579  * a security audit over a program.
580  *
581  * The general idea is that a program which uses just setregid() will be
582  * 100% compatible with BSD.  A program which uses just setgid() will be
583  * 100% compatible with POSIX with saved IDs. 
584  *
585  * SMP: There are not races, the GIDs are checked only by filesystem
586  *      operations (as far as semantic preservation is concerned).
587  */
588 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
589 {
590         int old_rgid = current->gid;
591         int old_egid = current->egid;
592         int new_rgid = old_rgid;
593         int new_egid = old_egid;
594         int retval;
595
596         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
597         if (retval)
598                 return retval;
599
600         if (rgid != (gid_t) -1) {
601                 if ((old_rgid == rgid) ||
602                     (current->egid==rgid) ||
603                     capable(CAP_SETGID))
604                         new_rgid = rgid;
605                 else
606                         return -EPERM;
607         }
608         if (egid != (gid_t) -1) {
609                 if ((old_rgid == egid) ||
610                     (current->egid == egid) ||
611                     (current->sgid == egid) ||
612                     capable(CAP_SETGID))
613                         new_egid = egid;
614                 else {
615                         return -EPERM;
616                 }
617         }
618         if (new_egid != old_egid)
619         {
620                 current->mm->dumpable = suid_dumpable;
621                 smp_wmb();
622         }
623         if (rgid != (gid_t) -1 ||
624             (egid != (gid_t) -1 && egid != old_rgid))
625                 current->sgid = new_egid;
626         current->fsgid = new_egid;
627         current->egid = new_egid;
628         current->gid = new_rgid;
629         key_fsgid_changed(current);
630         proc_id_connector(current, PROC_EVENT_GID);
631         return 0;
632 }
633
634 /*
635  * setgid() is implemented like SysV w/ SAVED_IDS 
636  *
637  * SMP: Same implicit races as above.
638  */
639 asmlinkage long sys_setgid(gid_t gid)
640 {
641         int old_egid = current->egid;
642         int retval;
643
644         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
645         if (retval)
646                 return retval;
647
648         if (capable(CAP_SETGID))
649         {
650                 if(old_egid != gid)
651                 {
652                         current->mm->dumpable = suid_dumpable;
653                         smp_wmb();
654                 }
655                 current->gid = current->egid = current->sgid = current->fsgid = gid;
656         }
657         else if ((gid == current->gid) || (gid == current->sgid))
658         {
659                 if(old_egid != gid)
660                 {
661                         current->mm->dumpable = suid_dumpable;
662                         smp_wmb();
663                 }
664                 current->egid = current->fsgid = gid;
665         }
666         else
667                 return -EPERM;
668
669         key_fsgid_changed(current);
670         proc_id_connector(current, PROC_EVENT_GID);
671         return 0;
672 }
673   
674 static int set_user(uid_t new_ruid, int dumpclear)
675 {
676         struct user_struct *new_user;
677
678         new_user = alloc_uid(new_ruid);
679         if (!new_user)
680                 return -EAGAIN;
681
682         if (atomic_read(&new_user->processes) >=
683                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
684                         new_user != &root_user) {
685                 free_uid(new_user);
686                 return -EAGAIN;
687         }
688
689         switch_uid(new_user);
690
691         if(dumpclear)
692         {
693                 current->mm->dumpable = suid_dumpable;
694                 smp_wmb();
695         }
696         current->uid = new_ruid;
697         return 0;
698 }
699
700 /*
701  * Unprivileged users may change the real uid to the effective uid
702  * or vice versa.  (BSD-style)
703  *
704  * If you set the real uid at all, or set the effective uid to a value not
705  * equal to the real uid, then the saved uid is set to the new effective uid.
706  *
707  * This makes it possible for a setuid program to completely drop its
708  * privileges, which is often a useful assertion to make when you are doing
709  * a security audit over a program.
710  *
711  * The general idea is that a program which uses just setreuid() will be
712  * 100% compatible with BSD.  A program which uses just setuid() will be
713  * 100% compatible with POSIX with saved IDs. 
714  */
715 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
716 {
717         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
718         int retval;
719
720         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
721         if (retval)
722                 return retval;
723
724         new_ruid = old_ruid = current->uid;
725         new_euid = old_euid = current->euid;
726         old_suid = current->suid;
727
728         if (ruid != (uid_t) -1) {
729                 new_ruid = ruid;
730                 if ((old_ruid != ruid) &&
731                     (current->euid != ruid) &&
732                     !capable(CAP_SETUID))
733                         return -EPERM;
734         }
735
736         if (euid != (uid_t) -1) {
737                 new_euid = euid;
738                 if ((old_ruid != euid) &&
739                     (current->euid != euid) &&
740                     (current->suid != euid) &&
741                     !capable(CAP_SETUID))
742                         return -EPERM;
743         }
744
745         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
746                 return -EAGAIN;
747
748         if (new_euid != old_euid)
749         {
750                 current->mm->dumpable = suid_dumpable;
751                 smp_wmb();
752         }
753         current->fsuid = current->euid = new_euid;
754         if (ruid != (uid_t) -1 ||
755             (euid != (uid_t) -1 && euid != old_ruid))
756                 current->suid = current->euid;
757         current->fsuid = current->euid;
758
759         key_fsuid_changed(current);
760         proc_id_connector(current, PROC_EVENT_UID);
761
762         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
763 }
764
765
766                 
767 /*
768  * setuid() is implemented like SysV with SAVED_IDS 
769  * 
770  * Note that SAVED_ID's is deficient in that a setuid root program
771  * like sendmail, for example, cannot set its uid to be a normal 
772  * user and then switch back, because if you're root, setuid() sets
773  * the saved uid too.  If you don't like this, blame the bright people
774  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
775  * will allow a root program to temporarily drop privileges and be able to
776  * regain them by swapping the real and effective uid.  
777  */
778 asmlinkage long sys_setuid(uid_t uid)
779 {
780         int old_euid = current->euid;
781         int old_ruid, old_suid, new_ruid, new_suid;
782         int retval;
783
784         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
785         if (retval)
786                 return retval;
787
788         old_ruid = new_ruid = current->uid;
789         old_suid = current->suid;
790         new_suid = old_suid;
791         
792         if (capable(CAP_SETUID)) {
793                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
794                         return -EAGAIN;
795                 new_suid = uid;
796         } else if ((uid != current->uid) && (uid != new_suid))
797                 return -EPERM;
798
799         if (old_euid != uid)
800         {
801                 current->mm->dumpable = suid_dumpable;
802                 smp_wmb();
803         }
804         current->fsuid = current->euid = uid;
805         current->suid = new_suid;
806
807         key_fsuid_changed(current);
808         proc_id_connector(current, PROC_EVENT_UID);
809
810         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
811 }
812
813
814 /*
815  * This function implements a generic ability to update ruid, euid,
816  * and suid.  This allows you to implement the 4.4 compatible seteuid().
817  */
818 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
819 {
820         int old_ruid = current->uid;
821         int old_euid = current->euid;
822         int old_suid = current->suid;
823         int retval;
824
825         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
826         if (retval)
827                 return retval;
828
829         if (!capable(CAP_SETUID)) {
830                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
831                     (ruid != current->euid) && (ruid != current->suid))
832                         return -EPERM;
833                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
834                     (euid != current->euid) && (euid != current->suid))
835                         return -EPERM;
836                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
837                     (suid != current->euid) && (suid != current->suid))
838                         return -EPERM;
839         }
840         if (ruid != (uid_t) -1) {
841                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
842                         return -EAGAIN;
843         }
844         if (euid != (uid_t) -1) {
845                 if (euid != current->euid)
846                 {
847                         current->mm->dumpable = suid_dumpable;
848                         smp_wmb();
849                 }
850                 current->euid = euid;
851         }
852         current->fsuid = current->euid;
853         if (suid != (uid_t) -1)
854                 current->suid = suid;
855
856         key_fsuid_changed(current);
857         proc_id_connector(current, PROC_EVENT_UID);
858
859         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
860 }
861
862 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
863 {
864         int retval;
865
866         if (!(retval = put_user(current->uid, ruid)) &&
867             !(retval = put_user(current->euid, euid)))
868                 retval = put_user(current->suid, suid);
869
870         return retval;
871 }
872
873 /*
874  * Same as above, but for rgid, egid, sgid.
875  */
876 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
877 {
878         int retval;
879
880         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
881         if (retval)
882                 return retval;
883
884         if (!capable(CAP_SETGID)) {
885                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
886                     (rgid != current->egid) && (rgid != current->sgid))
887                         return -EPERM;
888                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
889                     (egid != current->egid) && (egid != current->sgid))
890                         return -EPERM;
891                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
892                     (sgid != current->egid) && (sgid != current->sgid))
893                         return -EPERM;
894         }
895         if (egid != (gid_t) -1) {
896                 if (egid != current->egid)
897                 {
898                         current->mm->dumpable = suid_dumpable;
899                         smp_wmb();
900                 }
901                 current->egid = egid;
902         }
903         current->fsgid = current->egid;
904         if (rgid != (gid_t) -1)
905                 current->gid = rgid;
906         if (sgid != (gid_t) -1)
907                 current->sgid = sgid;
908
909         key_fsgid_changed(current);
910         proc_id_connector(current, PROC_EVENT_GID);
911         return 0;
912 }
913
914 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
915 {
916         int retval;
917
918         if (!(retval = put_user(current->gid, rgid)) &&
919             !(retval = put_user(current->egid, egid)))
920                 retval = put_user(current->sgid, sgid);
921
922         return retval;
923 }
924
925
926 /*
927  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
928  * is used for "access()" and for the NFS daemon (letting nfsd stay at
929  * whatever uid it wants to). It normally shadows "euid", except when
930  * explicitly set by setfsuid() or for access..
931  */
932 asmlinkage long sys_setfsuid(uid_t uid)
933 {
934         int old_fsuid;
935
936         old_fsuid = current->fsuid;
937         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
938                 return old_fsuid;
939
940         if (uid == current->uid || uid == current->euid ||
941             uid == current->suid || uid == current->fsuid || 
942             capable(CAP_SETUID))
943         {
944                 if (uid != old_fsuid)
945                 {
946                         current->mm->dumpable = suid_dumpable;
947                         smp_wmb();
948                 }
949                 current->fsuid = uid;
950         }
951
952         key_fsuid_changed(current);
953         proc_id_connector(current, PROC_EVENT_UID);
954
955         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
956
957         return old_fsuid;
958 }
959
960 /*
961  * Samma på svenska..
962  */
963 asmlinkage long sys_setfsgid(gid_t gid)
964 {
965         int old_fsgid;
966
967         old_fsgid = current->fsgid;
968         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
969                 return old_fsgid;
970
971         if (gid == current->gid || gid == current->egid ||
972             gid == current->sgid || gid == current->fsgid || 
973             capable(CAP_SETGID))
974         {
975                 if (gid != old_fsgid)
976                 {
977                         current->mm->dumpable = suid_dumpable;
978                         smp_wmb();
979                 }
980                 current->fsgid = gid;
981                 key_fsgid_changed(current);
982                 proc_id_connector(current, PROC_EVENT_GID);
983         }
984         return old_fsgid;
985 }
986
987 asmlinkage long sys_times(struct tms __user * tbuf)
988 {
989         /*
990          *      In the SMP world we might just be unlucky and have one of
991          *      the times increment as we use it. Since the value is an
992          *      atomically safe type this is just fine. Conceptually its
993          *      as if the syscall took an instant longer to occur.
994          */
995         if (tbuf) {
996                 struct tms tmp;
997                 cputime_t utime, stime, cutime, cstime;
998
999 #ifdef CONFIG_SMP
1000                 if (thread_group_empty(current)) {
1001                         /*
1002                          * Single thread case without the use of any locks.
1003                          *
1004                          * We may race with release_task if two threads are
1005                          * executing. However, release task first adds up the
1006                          * counters (__exit_signal) before  removing the task
1007                          * from the process tasklist (__unhash_process).
1008                          * __exit_signal also acquires and releases the
1009                          * siglock which results in the proper memory ordering
1010                          * so that the list modifications are always visible
1011                          * after the counters have been updated.
1012                          *
1013                          * If the counters have been updated by the second thread
1014                          * but the thread has not yet been removed from the list
1015                          * then the other branch will be executing which will
1016                          * block on tasklist_lock until the exit handling of the
1017                          * other task is finished.
1018                          *
1019                          * This also implies that the sighand->siglock cannot
1020                          * be held by another processor. So we can also
1021                          * skip acquiring that lock.
1022                          */
1023                         utime = cputime_add(current->signal->utime, current->utime);
1024                         stime = cputime_add(current->signal->utime, current->stime);
1025                         cutime = current->signal->cutime;
1026                         cstime = current->signal->cstime;
1027                 } else
1028 #endif
1029                 {
1030
1031                         /* Process with multiple threads */
1032                         struct task_struct *tsk = current;
1033                         struct task_struct *t;
1034
1035                         read_lock(&tasklist_lock);
1036                         utime = tsk->signal->utime;
1037                         stime = tsk->signal->stime;
1038                         t = tsk;
1039                         do {
1040                                 utime = cputime_add(utime, t->utime);
1041                                 stime = cputime_add(stime, t->stime);
1042                                 t = next_thread(t);
1043                         } while (t != tsk);
1044
1045                         /*
1046                          * While we have tasklist_lock read-locked, no dying thread
1047                          * can be updating current->signal->[us]time.  Instead,
1048                          * we got their counts included in the live thread loop.
1049                          * However, another thread can come in right now and
1050                          * do a wait call that updates current->signal->c[us]time.
1051                          * To make sure we always see that pair updated atomically,
1052                          * we take the siglock around fetching them.
1053                          */
1054                         spin_lock_irq(&tsk->sighand->siglock);
1055                         cutime = tsk->signal->cutime;
1056                         cstime = tsk->signal->cstime;
1057                         spin_unlock_irq(&tsk->sighand->siglock);
1058                         read_unlock(&tasklist_lock);
1059                 }
1060                 tmp.tms_utime = cputime_to_clock_t(utime);
1061                 tmp.tms_stime = cputime_to_clock_t(stime);
1062                 tmp.tms_cutime = cputime_to_clock_t(cutime);
1063                 tmp.tms_cstime = cputime_to_clock_t(cstime);
1064                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1065                         return -EFAULT;
1066         }
1067         return (long) jiffies_64_to_clock_t(get_jiffies_64());
1068 }
1069
1070 /*
1071  * This needs some heavy checking ...
1072  * I just haven't the stomach for it. I also don't fully
1073  * understand sessions/pgrp etc. Let somebody who does explain it.
1074  *
1075  * OK, I think I have the protection semantics right.... this is really
1076  * only important on a multi-user system anyway, to make sure one user
1077  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1078  *
1079  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1080  * LBT 04.03.94
1081  */
1082
1083 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1084 {
1085         struct task_struct *p;
1086         int err = -EINVAL;
1087
1088         if (!pid)
1089                 pid = current->pid;
1090         if (!pgid)
1091                 pgid = pid;
1092         if (pgid < 0)
1093                 return -EINVAL;
1094
1095         /* From this point forward we keep holding onto the tasklist lock
1096          * so that our parent does not change from under us. -DaveM
1097          */
1098         write_lock_irq(&tasklist_lock);
1099
1100         err = -ESRCH;
1101         p = find_task_by_pid(pid);
1102         if (!p)
1103                 goto out;
1104
1105         err = -EINVAL;
1106         if (!thread_group_leader(p))
1107                 goto out;
1108
1109         if (p->parent == current || p->real_parent == current) {
1110                 err = -EPERM;
1111                 if (p->signal->session != current->signal->session)
1112                         goto out;
1113                 err = -EACCES;
1114                 if (p->did_exec)
1115                         goto out;
1116         } else {
1117                 err = -ESRCH;
1118                 if (p != current)
1119                         goto out;
1120         }
1121
1122         err = -EPERM;
1123         if (p->signal->leader)
1124                 goto out;
1125
1126         if (pgid != pid) {
1127                 struct task_struct *p;
1128
1129                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1130                         if (p->signal->session == current->signal->session)
1131                                 goto ok_pgid;
1132                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1133                 goto out;
1134         }
1135
1136 ok_pgid:
1137         err = security_task_setpgid(p, pgid);
1138         if (err)
1139                 goto out;
1140
1141         if (process_group(p) != pgid) {
1142                 detach_pid(p, PIDTYPE_PGID);
1143                 p->signal->pgrp = pgid;
1144                 attach_pid(p, PIDTYPE_PGID, pgid);
1145         }
1146
1147         err = 0;
1148 out:
1149         /* All paths lead to here, thus we are safe. -DaveM */
1150         write_unlock_irq(&tasklist_lock);
1151         return err;
1152 }
1153
1154 asmlinkage long sys_getpgid(pid_t pid)
1155 {
1156         if (!pid) {
1157                 return process_group(current);
1158         } else {
1159                 int retval;
1160                 struct task_struct *p;
1161
1162                 read_lock(&tasklist_lock);
1163                 p = find_task_by_pid(pid);
1164
1165                 retval = -ESRCH;
1166                 if (p) {
1167                         retval = security_task_getpgid(p);
1168                         if (!retval)
1169                                 retval = process_group(p);
1170                 }
1171                 read_unlock(&tasklist_lock);
1172                 return retval;
1173         }
1174 }
1175
1176 #ifdef __ARCH_WANT_SYS_GETPGRP
1177
1178 asmlinkage long sys_getpgrp(void)
1179 {
1180         /* SMP - assuming writes are word atomic this is fine */
1181         return process_group(current);
1182 }
1183
1184 #endif
1185
1186 asmlinkage long sys_getsid(pid_t pid)
1187 {
1188         if (!pid) {
1189                 return current->signal->session;
1190         } else {
1191                 int retval;
1192                 struct task_struct *p;
1193
1194                 read_lock(&tasklist_lock);
1195                 p = find_task_by_pid(pid);
1196
1197                 retval = -ESRCH;
1198                 if(p) {
1199                         retval = security_task_getsid(p);
1200                         if (!retval)
1201                                 retval = p->signal->session;
1202                 }
1203                 read_unlock(&tasklist_lock);
1204                 return retval;
1205         }
1206 }
1207
1208 asmlinkage long sys_setsid(void)
1209 {
1210         struct pid *pid;
1211         int err = -EPERM;
1212
1213         if (!thread_group_leader(current))
1214                 return -EINVAL;
1215
1216         down(&tty_sem);
1217         write_lock_irq(&tasklist_lock);
1218
1219         pid = find_pid(PIDTYPE_PGID, current->pid);
1220         if (pid)
1221                 goto out;
1222
1223         current->signal->leader = 1;
1224         __set_special_pids(current->pid, current->pid);
1225         current->signal->tty = NULL;
1226         current->signal->tty_old_pgrp = 0;
1227         err = process_group(current);
1228 out:
1229         write_unlock_irq(&tasklist_lock);
1230         up(&tty_sem);
1231         return err;
1232 }
1233
1234 /*
1235  * Supplementary group IDs
1236  */
1237
1238 /* init to 2 - one for init_task, one to ensure it is never freed */
1239 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1240
1241 struct group_info *groups_alloc(int gidsetsize)
1242 {
1243         struct group_info *group_info;
1244         int nblocks;
1245         int i;
1246
1247         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1248         /* Make sure we always allocate at least one indirect block pointer */
1249         nblocks = nblocks ? : 1;
1250         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1251         if (!group_info)
1252                 return NULL;
1253         group_info->ngroups = gidsetsize;
1254         group_info->nblocks = nblocks;
1255         atomic_set(&group_info->usage, 1);
1256
1257         if (gidsetsize <= NGROUPS_SMALL) {
1258                 group_info->blocks[0] = group_info->small_block;
1259         } else {
1260                 for (i = 0; i < nblocks; i++) {
1261                         gid_t *b;
1262                         b = (void *)__get_free_page(GFP_USER);
1263                         if (!b)
1264                                 goto out_undo_partial_alloc;
1265                         group_info->blocks[i] = b;
1266                 }
1267         }
1268         return group_info;
1269
1270 out_undo_partial_alloc:
1271         while (--i >= 0) {
1272                 free_page((unsigned long)group_info->blocks[i]);
1273         }
1274         kfree(group_info);
1275         return NULL;
1276 }
1277
1278 EXPORT_SYMBOL(groups_alloc);
1279
1280 void groups_free(struct group_info *group_info)
1281 {
1282         if (group_info->blocks[0] != group_info->small_block) {
1283                 int i;
1284                 for (i = 0; i < group_info->nblocks; i++)
1285                         free_page((unsigned long)group_info->blocks[i]);
1286         }
1287         kfree(group_info);
1288 }
1289
1290 EXPORT_SYMBOL(groups_free);
1291
1292 /* export the group_info to a user-space array */
1293 static int groups_to_user(gid_t __user *grouplist,
1294     struct group_info *group_info)
1295 {
1296         int i;
1297         int count = group_info->ngroups;
1298
1299         for (i = 0; i < group_info->nblocks; i++) {
1300                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1301                 int off = i * NGROUPS_PER_BLOCK;
1302                 int len = cp_count * sizeof(*grouplist);
1303
1304                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1305                         return -EFAULT;
1306
1307                 count -= cp_count;
1308         }
1309         return 0;
1310 }
1311
1312 /* fill a group_info from a user-space array - it must be allocated already */
1313 static int groups_from_user(struct group_info *group_info,
1314     gid_t __user *grouplist)
1315  {
1316         int i;
1317         int count = group_info->ngroups;
1318
1319         for (i = 0; i < group_info->nblocks; i++) {
1320                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1321                 int off = i * NGROUPS_PER_BLOCK;
1322                 int len = cp_count * sizeof(*grouplist);
1323
1324                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1325                         return -EFAULT;
1326
1327                 count -= cp_count;
1328         }
1329         return 0;
1330 }
1331
1332 /* a simple Shell sort */
1333 static void groups_sort(struct group_info *group_info)
1334 {
1335         int base, max, stride;
1336         int gidsetsize = group_info->ngroups;
1337
1338         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1339                 ; /* nothing */
1340         stride /= 3;
1341
1342         while (stride) {
1343                 max = gidsetsize - stride;
1344                 for (base = 0; base < max; base++) {
1345                         int left = base;
1346                         int right = left + stride;
1347                         gid_t tmp = GROUP_AT(group_info, right);
1348
1349                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1350                                 GROUP_AT(group_info, right) =
1351                                     GROUP_AT(group_info, left);
1352                                 right = left;
1353                                 left -= stride;
1354                         }
1355                         GROUP_AT(group_info, right) = tmp;
1356                 }
1357                 stride /= 3;
1358         }
1359 }
1360
1361 /* a simple bsearch */
1362 int groups_search(struct group_info *group_info, gid_t grp)
1363 {
1364         int left, right;
1365
1366         if (!group_info)
1367                 return 0;
1368
1369         left = 0;
1370         right = group_info->ngroups;
1371         while (left < right) {
1372                 int mid = (left+right)/2;
1373                 int cmp = grp - GROUP_AT(group_info, mid);
1374                 if (cmp > 0)
1375                         left = mid + 1;
1376                 else if (cmp < 0)
1377                         right = mid;
1378                 else
1379                         return 1;
1380         }
1381         return 0;
1382 }
1383
1384 /* validate and set current->group_info */
1385 int set_current_groups(struct group_info *group_info)
1386 {
1387         int retval;
1388         struct group_info *old_info;
1389
1390         retval = security_task_setgroups(group_info);
1391         if (retval)
1392                 return retval;
1393
1394         groups_sort(group_info);
1395         get_group_info(group_info);
1396
1397         task_lock(current);
1398         old_info = current->group_info;
1399         current->group_info = group_info;
1400         task_unlock(current);
1401
1402         put_group_info(old_info);
1403
1404         return 0;
1405 }
1406
1407 EXPORT_SYMBOL(set_current_groups);
1408
1409 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1410 {
1411         int i = 0;
1412
1413         /*
1414          *      SMP: Nobody else can change our grouplist. Thus we are
1415          *      safe.
1416          */
1417
1418         if (gidsetsize < 0)
1419                 return -EINVAL;
1420
1421         /* no need to grab task_lock here; it cannot change */
1422         get_group_info(current->group_info);
1423         i = current->group_info->ngroups;
1424         if (gidsetsize) {
1425                 if (i > gidsetsize) {
1426                         i = -EINVAL;
1427                         goto out;
1428                 }
1429                 if (groups_to_user(grouplist, current->group_info)) {
1430                         i = -EFAULT;
1431                         goto out;
1432                 }
1433         }
1434 out:
1435         put_group_info(current->group_info);
1436         return i;
1437 }
1438
1439 /*
1440  *      SMP: Our groups are copy-on-write. We can set them safely
1441  *      without another task interfering.
1442  */
1443  
1444 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1445 {
1446         struct group_info *group_info;
1447         int retval;
1448
1449         if (!capable(CAP_SETGID))
1450                 return -EPERM;
1451         if ((unsigned)gidsetsize > NGROUPS_MAX)
1452                 return -EINVAL;
1453
1454         group_info = groups_alloc(gidsetsize);
1455         if (!group_info)
1456                 return -ENOMEM;
1457         retval = groups_from_user(group_info, grouplist);
1458         if (retval) {
1459                 put_group_info(group_info);
1460                 return retval;
1461         }
1462
1463         retval = set_current_groups(group_info);
1464         put_group_info(group_info);
1465
1466         return retval;
1467 }
1468
1469 /*
1470  * Check whether we're fsgid/egid or in the supplemental group..
1471  */
1472 int in_group_p(gid_t grp)
1473 {
1474         int retval = 1;
1475         if (grp != current->fsgid) {
1476                 get_group_info(current->group_info);
1477                 retval = groups_search(current->group_info, grp);
1478                 put_group_info(current->group_info);
1479         }
1480         return retval;
1481 }
1482
1483 EXPORT_SYMBOL(in_group_p);
1484
1485 int in_egroup_p(gid_t grp)
1486 {
1487         int retval = 1;
1488         if (grp != current->egid) {
1489                 get_group_info(current->group_info);
1490                 retval = groups_search(current->group_info, grp);
1491                 put_group_info(current->group_info);
1492         }
1493         return retval;
1494 }
1495
1496 EXPORT_SYMBOL(in_egroup_p);
1497
1498 DECLARE_RWSEM(uts_sem);
1499
1500 EXPORT_SYMBOL(uts_sem);
1501
1502 asmlinkage long sys_newuname(struct new_utsname __user * name)
1503 {
1504         int errno = 0;
1505
1506         down_read(&uts_sem);
1507         if (copy_to_user(name,&system_utsname,sizeof *name))
1508                 errno = -EFAULT;
1509         up_read(&uts_sem);
1510         return errno;
1511 }
1512
1513 asmlinkage long sys_sethostname(char __user *name, int len)
1514 {
1515         int errno;
1516         char tmp[__NEW_UTS_LEN];
1517
1518         if (!capable(CAP_SYS_ADMIN))
1519                 return -EPERM;
1520         if (len < 0 || len > __NEW_UTS_LEN)
1521                 return -EINVAL;
1522         down_write(&uts_sem);
1523         errno = -EFAULT;
1524         if (!copy_from_user(tmp, name, len)) {
1525                 memcpy(system_utsname.nodename, tmp, len);
1526                 system_utsname.nodename[len] = 0;
1527                 errno = 0;
1528         }
1529         up_write(&uts_sem);
1530         return errno;
1531 }
1532
1533 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1534
1535 asmlinkage long sys_gethostname(char __user *name, int len)
1536 {
1537         int i, errno;
1538
1539         if (len < 0)
1540                 return -EINVAL;
1541         down_read(&uts_sem);
1542         i = 1 + strlen(system_utsname.nodename);
1543         if (i > len)
1544                 i = len;
1545         errno = 0;
1546         if (copy_to_user(name, system_utsname.nodename, i))
1547                 errno = -EFAULT;
1548         up_read(&uts_sem);
1549         return errno;
1550 }
1551
1552 #endif
1553
1554 /*
1555  * Only setdomainname; getdomainname can be implemented by calling
1556  * uname()
1557  */
1558 asmlinkage long sys_setdomainname(char __user *name, int len)
1559 {
1560         int errno;
1561         char tmp[__NEW_UTS_LEN];
1562
1563         if (!capable(CAP_SYS_ADMIN))
1564                 return -EPERM;
1565         if (len < 0 || len > __NEW_UTS_LEN)
1566                 return -EINVAL;
1567
1568         down_write(&uts_sem);
1569         errno = -EFAULT;
1570         if (!copy_from_user(tmp, name, len)) {
1571                 memcpy(system_utsname.domainname, tmp, len);
1572                 system_utsname.domainname[len] = 0;
1573                 errno = 0;
1574         }
1575         up_write(&uts_sem);
1576         return errno;
1577 }
1578
1579 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1580 {
1581         if (resource >= RLIM_NLIMITS)
1582                 return -EINVAL;
1583         else {
1584                 struct rlimit value;
1585                 task_lock(current->group_leader);
1586                 value = current->signal->rlim[resource];
1587                 task_unlock(current->group_leader);
1588                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1589         }
1590 }
1591
1592 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1593
1594 /*
1595  *      Back compatibility for getrlimit. Needed for some apps.
1596  */
1597  
1598 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1599 {
1600         struct rlimit x;
1601         if (resource >= RLIM_NLIMITS)
1602                 return -EINVAL;
1603
1604         task_lock(current->group_leader);
1605         x = current->signal->rlim[resource];
1606         task_unlock(current->group_leader);
1607         if(x.rlim_cur > 0x7FFFFFFF)
1608                 x.rlim_cur = 0x7FFFFFFF;
1609         if(x.rlim_max > 0x7FFFFFFF)
1610                 x.rlim_max = 0x7FFFFFFF;
1611         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1612 }
1613
1614 #endif
1615
1616 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1617 {
1618         struct rlimit new_rlim, *old_rlim;
1619         int retval;
1620
1621         if (resource >= RLIM_NLIMITS)
1622                 return -EINVAL;
1623         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1624                 return -EFAULT;
1625        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1626                return -EINVAL;
1627         old_rlim = current->signal->rlim + resource;
1628         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1629             !capable(CAP_SYS_RESOURCE))
1630                 return -EPERM;
1631         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1632                         return -EPERM;
1633
1634         retval = security_task_setrlimit(resource, &new_rlim);
1635         if (retval)
1636                 return retval;
1637
1638         task_lock(current->group_leader);
1639         *old_rlim = new_rlim;
1640         task_unlock(current->group_leader);
1641
1642         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1643             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1644              new_rlim.rlim_cur <= cputime_to_secs(
1645                      current->signal->it_prof_expires))) {
1646                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1647                 read_lock(&tasklist_lock);
1648                 spin_lock_irq(&current->sighand->siglock);
1649                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1650                                       &cputime, NULL);
1651                 spin_unlock_irq(&current->sighand->siglock);
1652                 read_unlock(&tasklist_lock);
1653         }
1654
1655         return 0;
1656 }
1657
1658 /*
1659  * It would make sense to put struct rusage in the task_struct,
1660  * except that would make the task_struct be *really big*.  After
1661  * task_struct gets moved into malloc'ed memory, it would
1662  * make sense to do this.  It will make moving the rest of the information
1663  * a lot simpler!  (Which we're not doing right now because we're not
1664  * measuring them yet).
1665  *
1666  * This expects to be called with tasklist_lock read-locked or better,
1667  * and the siglock not locked.  It may momentarily take the siglock.
1668  *
1669  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1670  * races with threads incrementing their own counters.  But since word
1671  * reads are atomic, we either get new values or old values and we don't
1672  * care which for the sums.  We always take the siglock to protect reading
1673  * the c* fields from p->signal from races with exit.c updating those
1674  * fields when reaping, so a sample either gets all the additions of a
1675  * given child after it's reaped, or none so this sample is before reaping.
1676  */
1677
1678 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1679 {
1680         struct task_struct *t;
1681         unsigned long flags;
1682         cputime_t utime, stime;
1683
1684         memset((char *) r, 0, sizeof *r);
1685
1686         if (unlikely(!p->signal))
1687                 return;
1688
1689         switch (who) {
1690                 case RUSAGE_CHILDREN:
1691                         spin_lock_irqsave(&p->sighand->siglock, flags);
1692                         utime = p->signal->cutime;
1693                         stime = p->signal->cstime;
1694                         r->ru_nvcsw = p->signal->cnvcsw;
1695                         r->ru_nivcsw = p->signal->cnivcsw;
1696                         r->ru_minflt = p->signal->cmin_flt;
1697                         r->ru_majflt = p->signal->cmaj_flt;
1698                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1699                         cputime_to_timeval(utime, &r->ru_utime);
1700                         cputime_to_timeval(stime, &r->ru_stime);
1701                         break;
1702                 case RUSAGE_SELF:
1703                         spin_lock_irqsave(&p->sighand->siglock, flags);
1704                         utime = stime = cputime_zero;
1705                         goto sum_group;
1706                 case RUSAGE_BOTH:
1707                         spin_lock_irqsave(&p->sighand->siglock, flags);
1708                         utime = p->signal->cutime;
1709                         stime = p->signal->cstime;
1710                         r->ru_nvcsw = p->signal->cnvcsw;
1711                         r->ru_nivcsw = p->signal->cnivcsw;
1712                         r->ru_minflt = p->signal->cmin_flt;
1713                         r->ru_majflt = p->signal->cmaj_flt;
1714                 sum_group:
1715                         utime = cputime_add(utime, p->signal->utime);
1716                         stime = cputime_add(stime, p->signal->stime);
1717                         r->ru_nvcsw += p->signal->nvcsw;
1718                         r->ru_nivcsw += p->signal->nivcsw;
1719                         r->ru_minflt += p->signal->min_flt;
1720                         r->ru_majflt += p->signal->maj_flt;
1721                         t = p;
1722                         do {
1723                                 utime = cputime_add(utime, t->utime);
1724                                 stime = cputime_add(stime, t->stime);
1725                                 r->ru_nvcsw += t->nvcsw;
1726                                 r->ru_nivcsw += t->nivcsw;
1727                                 r->ru_minflt += t->min_flt;
1728                                 r->ru_majflt += t->maj_flt;
1729                                 t = next_thread(t);
1730                         } while (t != p);
1731                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1732                         cputime_to_timeval(utime, &r->ru_utime);
1733                         cputime_to_timeval(stime, &r->ru_stime);
1734                         break;
1735                 default:
1736                         BUG();
1737         }
1738 }
1739
1740 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1741 {
1742         struct rusage r;
1743         read_lock(&tasklist_lock);
1744         k_getrusage(p, who, &r);
1745         read_unlock(&tasklist_lock);
1746         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1747 }
1748
1749 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1750 {
1751         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1752                 return -EINVAL;
1753         return getrusage(current, who, ru);
1754 }
1755
1756 asmlinkage long sys_umask(int mask)
1757 {
1758         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1759         return mask;
1760 }
1761     
1762 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1763                           unsigned long arg4, unsigned long arg5)
1764 {
1765         long error;
1766
1767         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1768         if (error)
1769                 return error;
1770
1771         switch (option) {
1772                 case PR_SET_PDEATHSIG:
1773                         if (!valid_signal(arg2)) {
1774                                 error = -EINVAL;
1775                                 break;
1776                         }
1777                         current->pdeath_signal = arg2;
1778                         break;
1779                 case PR_GET_PDEATHSIG:
1780                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1781                         break;
1782                 case PR_GET_DUMPABLE:
1783                         error = current->mm->dumpable;
1784                         break;
1785                 case PR_SET_DUMPABLE:
1786                         if (arg2 < 0 || arg2 > 2) {
1787                                 error = -EINVAL;
1788                                 break;
1789                         }
1790                         current->mm->dumpable = arg2;
1791                         break;
1792
1793                 case PR_SET_UNALIGN:
1794                         error = SET_UNALIGN_CTL(current, arg2);
1795                         break;
1796                 case PR_GET_UNALIGN:
1797                         error = GET_UNALIGN_CTL(current, arg2);
1798                         break;
1799                 case PR_SET_FPEMU:
1800                         error = SET_FPEMU_CTL(current, arg2);
1801                         break;
1802                 case PR_GET_FPEMU:
1803                         error = GET_FPEMU_CTL(current, arg2);
1804                         break;
1805                 case PR_SET_FPEXC:
1806                         error = SET_FPEXC_CTL(current, arg2);
1807                         break;
1808                 case PR_GET_FPEXC:
1809                         error = GET_FPEXC_CTL(current, arg2);
1810                         break;
1811                 case PR_GET_TIMING:
1812                         error = PR_TIMING_STATISTICAL;
1813                         break;
1814                 case PR_SET_TIMING:
1815                         if (arg2 == PR_TIMING_STATISTICAL)
1816                                 error = 0;
1817                         else
1818                                 error = -EINVAL;
1819                         break;
1820
1821                 case PR_GET_KEEPCAPS:
1822                         if (current->keep_capabilities)
1823                                 error = 1;
1824                         break;
1825                 case PR_SET_KEEPCAPS:
1826                         if (arg2 != 0 && arg2 != 1) {
1827                                 error = -EINVAL;
1828                                 break;
1829                         }
1830                         current->keep_capabilities = arg2;
1831                         break;
1832                 case PR_SET_NAME: {
1833                         struct task_struct *me = current;
1834                         unsigned char ncomm[sizeof(me->comm)];
1835
1836                         ncomm[sizeof(me->comm)-1] = 0;
1837                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1838                                                 sizeof(me->comm)-1) < 0)
1839                                 return -EFAULT;
1840                         set_task_comm(me, ncomm);
1841                         return 0;
1842                 }
1843                 case PR_GET_NAME: {
1844                         struct task_struct *me = current;
1845                         unsigned char tcomm[sizeof(me->comm)];
1846
1847                         get_task_comm(tcomm, me);
1848                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1849                                 return -EFAULT;
1850                         return 0;
1851                 }
1852                 default:
1853                         error = -EINVAL;
1854                         break;
1855         }
1856         return error;
1857 }