1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/smp_lock.h>
12 #include <linux/notifier.h>
13 #include <linux/reboot.h>
14 #include <linux/prctl.h>
15 #include <linux/init.h>
16 #include <linux/highuid.h>
17
18 #include <asm/uaccess.h>
19 #include <asm/io.h>
20
21 /*
22 * this is where the system-wide overflow UID and GID are defined, for
23 * architectures that now have 32-bit UID/GID but didn't in the past
24 */
25
26 int overflowuid = DEFAULT_OVERFLOWUID;
27 int overflowgid = DEFAULT_OVERFLOWGID;
28
29 /*
30 * the same as above, but for filesystems which can only store a 16-bit
31 * UID and GID. as such, this is needed on all architectures
32 */
33
34 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
35 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
36
37 /*
38 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
39 */
40
41 int C_A_D = 1;
42
43
44 /*
45 * Notifier list for kernel code which wants to be called
46 * at shutdown. This is used to stop any idling DMA operations
47 * and the like.
48 */
49
50 static struct notifier_block *reboot_notifier_list;
51 rwlock_t notifier_lock = RW_LOCK_UNLOCKED;
52
53 /**
54 * notifier_chain_register - Add notifier to a notifier chain
55 * @list: Pointer to root list pointer
56 * @n: New entry in notifier chain
57 *
58 * Adds a notifier to a notifier chain.
59 *
60 * Currently always returns zero.
61 */
62
63 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
64 {
65 write_lock(¬ifier_lock);
66 while(*list)
67 {
68 if(n->priority > (*list)->priority)
69 break;
70 list= &((*list)->next);
71 }
72 n->next = *list;
73 *list=n;
74 write_unlock(¬ifier_lock);
75 return 0;
76 }
77
78 /**
79 * notifier_chain_unregister - Remove notifier from a notifier chain
80 * @nl: Pointer to root list pointer
81 * @n: New entry in notifier chain
82 *
83 * Removes a notifier from a notifier chain.
84 *
85 * Returns zero on success, or %-ENOENT on failure.
86 */
87
88 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
89 {
90 write_lock(¬ifier_lock);
91 while((*nl)!=NULL)
92 {
93 if((*nl)==n)
94 {
95 *nl=n->next;
96 write_unlock(¬ifier_lock);
97 return 0;
98 }
99 nl=&((*nl)->next);
100 }
101 write_unlock(¬ifier_lock);
102 return -ENOENT;
103 }
104
105 /**
106 * notifier_call_chain - Call functions in a notifier chain
107 * @n: Pointer to root pointer of notifier chain
108 * @val: Value passed unmodified to notifier function
109 * @v: Pointer passed unmodified to notifier function
110 *
111 * Calls each function in a notifier chain in turn.
112 *
113 * If the return value of the notifier can be and'd
114 * with %NOTIFY_STOP_MASK, then notifier_call_chain
115 * will return immediately, with the return value of
116 * the notifier function which halted execution.
117 * Otherwise, the return value is the return value
118 * of the last notifier function called.
119 */
120
121 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
122 {
123 int ret=NOTIFY_DONE;
124 struct notifier_block *nb = *n;
125
126 while(nb)
127 {
128 ret=nb->notifier_call(nb,val,v);
129 if(ret&NOTIFY_STOP_MASK)
130 {
131 return ret;
132 }
133 nb=nb->next;
134 }
135 return ret;
136 }
137
138 /**
139 * register_reboot_notifier - Register function to be called at reboot time
140 * @nb: Info about notifier function to be called
141 *
142 * Registers a function with the list of functions
143 * to be called at reboot time.
144 *
145 * Currently always returns zero, as notifier_chain_register
146 * always returns zero.
147 */
148
149 int register_reboot_notifier(struct notifier_block * nb)
150 {
151 return notifier_chain_register(&reboot_notifier_list, nb);
152 }
153
154 /**
155 * unregister_reboot_notifier - Unregister previously registered reboot notifier
156 * @nb: Hook to be unregistered
157 *
158 * Unregisters a previously registered reboot
159 * notifier function.
160 *
161 * Returns zero on success, or %-ENOENT on failure.
162 */
163
164 int unregister_reboot_notifier(struct notifier_block * nb)
165 {
166 return notifier_chain_unregister(&reboot_notifier_list, nb);
167 }
168
169 asmlinkage long sys_ni_syscall(void)
170 {
171 return -ENOSYS;
172 }
173
174 static int proc_sel(struct task_struct *p, int which, int who)
175 {
176 if(p->pid)
177 {
178 switch (which) {
179 case PRIO_PROCESS:
180 if (!who && p == current)
181 return 1;
182 return(p->pid == who);
183 case PRIO_PGRP:
184 if (!who)
185 who = current->pgrp;
186 return(p->pgrp == who);
187 case PRIO_USER:
188 if (!who)
189 who = current->uid;
190 return(p->uid == who);
191 }
192 }
193 return 0;
194 }
195
196 asmlinkage long sys_setpriority(int which, int who, int niceval)
197 {
198 struct task_struct *p;
199 int error;
200
201 if (which > 2 || which < 0)
202 return -EINVAL;
203
204 /* normalize: avoid signed division (rounding problems) */
205 error = -ESRCH;
206 if (niceval < -20)
207 niceval = -20;
208 if (niceval > 19)
209 niceval = 19;
210
211 read_lock(&tasklist_lock);
212 for_each_task(p) {
213 if (!proc_sel(p, which, who))
214 continue;
215 if (p->uid != current->euid &&
216 p->uid != current->uid && !capable(CAP_SYS_NICE)) {
217 error = -EPERM;
218 continue;
219 }
220 if (error == -ESRCH)
221 error = 0;
222 if (niceval < p->nice && !capable(CAP_SYS_NICE))
223 error = -EACCES;
224 else
225 p->nice = niceval;
226 }
227 read_unlock(&tasklist_lock);
228
229 return error;
230 }
231
232 /*
233 * Ugh. To avoid negative return values, "getpriority()" will
234 * not return the normal nice-value, but a negated value that
235 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
236 * to stay compatible.
237 */
238 asmlinkage long sys_getpriority(int which, int who)
239 {
240 struct task_struct *p;
241 long retval = -ESRCH;
242
243 if (which > 2 || which < 0)
244 return -EINVAL;
245
246 read_lock(&tasklist_lock);
247 for_each_task (p) {
248 long niceval;
249 if (!proc_sel(p, which, who))
250 continue;
251 niceval = 20 - p->nice;
252 if (niceval > retval)
253 retval = niceval;
254 }
255 read_unlock(&tasklist_lock);
256
257 return retval;
258 }
259
260
261 /*
262 * Reboot system call: for obvious reasons only root may call it,
263 * and even root needs to set up some magic numbers in the registers
264 * so that some mistake won't make this reboot the whole machine.
265 * You can also set the meaning of the ctrl-alt-del-key here.
266 *
267 * reboot doesn't sync: do that yourself before calling this.
268 */
269 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
270 {
271 char buffer[256];
272
273 /* We only trust the superuser with rebooting the system. */
274 if (!capable(CAP_SYS_BOOT))
275 return -EPERM;
276
277 /* For safety, we require "magic" arguments. */
278 if (magic1 != LINUX_REBOOT_MAGIC1 ||
279 (magic2 != LINUX_REBOOT_MAGIC2 && magic2 != LINUX_REBOOT_MAGIC2A &&
280 magic2 != LINUX_REBOOT_MAGIC2B))
281 return -EINVAL;
282
283 lock_kernel();
284 switch (cmd) {
285 case LINUX_REBOOT_CMD_RESTART:
286 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
287 printk(KERN_EMERG "Restarting system.\n");
288 machine_restart(NULL);
289 break;
290
291 case LINUX_REBOOT_CMD_CAD_ON:
292 C_A_D = 1;
293 break;
294
295 case LINUX_REBOOT_CMD_CAD_OFF:
296 C_A_D = 0;
297 break;
298
299 case LINUX_REBOOT_CMD_HALT:
300 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
301 printk(KERN_EMERG "System halted.\n");
302 machine_halt();
303 do_exit(0);
304 break;
305
306 case LINUX_REBOOT_CMD_POWER_OFF:
307 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
308 printk(KERN_EMERG "Power down.\n");
309 machine_power_off();
310 do_exit(0);
311 break;
312
313 case LINUX_REBOOT_CMD_RESTART2:
314 if (strncpy_from_user(&buffer[0], (char *)arg, sizeof(buffer) - 1) < 0) {
315 unlock_kernel();
316 return -EFAULT;
317 }
318 buffer[sizeof(buffer) - 1] = '\0';
319
320 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
321 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
322 machine_restart(buffer);
323 break;
324
325 default:
326 unlock_kernel();
327 return -EINVAL;
328 }
329 unlock_kernel();
330 return 0;
331 }
332
333 /*
334 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
335 * As it's called within an interrupt, it may NOT sync: the only choice
336 * is whether to reboot at once, or just ignore the ctrl-alt-del.
337 */
338 void ctrl_alt_del(void)
339 {
340 if (C_A_D) {
341 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
342 machine_restart(NULL);
343 } else
344 kill_proc(1, SIGINT, 1);
345 }
346
347
348 /*
349 * Unprivileged users may change the real gid to the effective gid
350 * or vice versa. (BSD-style)
351 *
352 * If you set the real gid at all, or set the effective gid to a value not
353 * equal to the real gid, then the saved gid is set to the new effective gid.
354 *
355 * This makes it possible for a setgid program to completely drop its
356 * privileges, which is often a useful assertion to make when you are doing
357 * a security audit over a program.
358 *
359 * The general idea is that a program which uses just setregid() will be
360 * 100% compatible with BSD. A program which uses just setgid() will be
361 * 100% compatible with POSIX with saved IDs.
362 *
363 * SMP: There are not races, the GIDs are checked only by filesystem
364 * operations (as far as semantic preservation is concerned).
365 */
366 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
367 {
368 int old_rgid = current->gid;
369 int old_egid = current->egid;
370
371 if (rgid != (gid_t) -1) {
372 if ((old_rgid == rgid) ||
373 (current->egid==rgid) ||
374 capable(CAP_SETGID))
375 current->gid = rgid;
376 else
377 return -EPERM;
378 }
379 if (egid != (gid_t) -1) {
380 if ((old_rgid == egid) ||
381 (current->egid == egid) ||
382 (current->sgid == egid) ||
383 capable(CAP_SETGID))
384 current->fsgid = current->egid = egid;
385 else {
386 current->gid = old_rgid;
387 return -EPERM;
388 }
389 }
390 if (rgid != (gid_t) -1 ||
391 (egid != (gid_t) -1 && egid != old_rgid))
392 current->sgid = current->egid;
393 current->fsgid = current->egid;
394 if (current->egid != old_egid)
395 current->dumpable = 0;
396 return 0;
397 }
398
399 /*
400 * setgid() is implemented like SysV w/ SAVED_IDS
401 *
402 * SMP: Same implicit races as above.
403 */
404 asmlinkage long sys_setgid(gid_t gid)
405 {
406 int old_egid = current->egid;
407
408 if (capable(CAP_SETGID))
409 current->gid = current->egid = current->sgid = current->fsgid = gid;
410 else if ((gid == current->gid) || (gid == current->sgid))
411 current->egid = current->fsgid = gid;
412 else
413 return -EPERM;
414
415 if (current->egid != old_egid)
416 current->dumpable = 0;
417 return 0;
418 }
419
420 /*
421 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
422 * a process after a call to setuid, setreuid, or setresuid.
423 *
424 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
425 * {r,e,s}uid != 0, the permitted and effective capabilities are
426 * cleared.
427 *
428 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
429 * capabilities of the process are cleared.
430 *
431 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
432 * capabilities are set to the permitted capabilities.
433 *
434 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
435 * never happen.
436 *
437 * -astor
438 *
439 * cevans - New behaviour, Oct '99
440 * A process may, via prctl(), elect to keep its capabilities when it
441 * calls setuid() and switches away from uid==0. Both permitted and
442 * effective sets will be retained.
443 * Without this change, it was impossible for a daemon to drop only some
444 * of its privilege. The call to setuid(!=0) would drop all privileges!
445 * Keeping uid 0 is not an option because uid 0 owns too many vital
446 * files..
447 * Thanks to Olaf Kirch and Peter Benie for spotting this.
448 */
449 extern inline void cap_emulate_setxuid(int old_ruid, int old_euid,
450 int old_suid)
451 {
452 if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
453 (current->uid != 0 && current->euid != 0 && current->suid != 0) &&
454 !current->keep_capabilities) {
455 cap_clear(current->cap_permitted);
456 cap_clear(current->cap_effective);
457 }
458 if (old_euid == 0 && current->euid != 0) {
459 cap_clear(current->cap_effective);
460 }
461 if (old_euid != 0 && current->euid == 0) {
462 current->cap_effective = current->cap_permitted;
463 }
464 }
465
466 static int set_user(uid_t new_ruid)
467 {
468 struct user_struct *new_user, *old_user;
469
470 /* What if a process setreuid()'s and this brings the
471 * new uid over his NPROC rlimit? We can check this now
472 * cheaply with the new uid cache, so if it matters
473 * we should be checking for it. -DaveM
474 */
475 new_user = alloc_uid(new_ruid);
476 if (!new_user)
477 return -EAGAIN;
478 old_user = current->user;
479 atomic_dec(&old_user->processes);
480 atomic_inc(&new_user->processes);
481
482 current->uid = new_ruid;
483 current->user = new_user;
484 free_uid(old_user);
485 return 0;
486 }
487
488 /*
489 * Unprivileged users may change the real uid to the effective uid
490 * or vice versa. (BSD-style)
491 *
492 * If you set the real uid at all, or set the effective uid to a value not
493 * equal to the real uid, then the saved uid is set to the new effective uid.
494 *
495 * This makes it possible for a setuid program to completely drop its
496 * privileges, which is often a useful assertion to make when you are doing
497 * a security audit over a program.
498 *
499 * The general idea is that a program which uses just setreuid() will be
500 * 100% compatible with BSD. A program which uses just setuid() will be
501 * 100% compatible with POSIX with saved IDs.
502 */
503 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
504 {
505 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
506
507 new_ruid = old_ruid = current->uid;
508 new_euid = old_euid = current->euid;
509 old_suid = current->suid;
510
511 if (ruid != (uid_t) -1) {
512 new_ruid = ruid;
513 if ((old_ruid != ruid) &&
514 (current->euid != ruid) &&
515 !capable(CAP_SETUID))
516 return -EPERM;
517 }
518
519 if (euid != (uid_t) -1) {
520 new_euid = euid;
521 if ((old_ruid != euid) &&
522 (current->euid != euid) &&
523 (current->suid != euid) &&
524 !capable(CAP_SETUID))
525 return -EPERM;
526 }
527
528 if (new_ruid != old_ruid && set_user(new_ruid) < 0)
529 return -EAGAIN;
530
531 current->fsuid = current->euid = new_euid;
532 if (ruid != (uid_t) -1 ||
533 (euid != (uid_t) -1 && euid != old_ruid))
534 current->suid = current->euid;
535 current->fsuid = current->euid;
536 if (current->euid != old_euid)
537 current->dumpable = 0;
538
539 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
540 cap_emulate_setxuid(old_ruid, old_euid, old_suid);
541 }
542
543 return 0;
544 }
545
546
547
548 /*
549 * setuid() is implemented like SysV with SAVED_IDS
550 *
551 * Note that SAVED_ID's is deficient in that a setuid root program
552 * like sendmail, for example, cannot set its uid to be a normal
553 * user and then switch back, because if you're root, setuid() sets
554 * the saved uid too. If you don't like this, blame the bright people
555 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
556 * will allow a root program to temporarily drop privileges and be able to
557 * regain them by swapping the real and effective uid.
558 */
559 asmlinkage long sys_setuid(uid_t uid)
560 {
561 int old_euid = current->euid;
562 int old_ruid, old_suid, new_ruid;
563
564 old_ruid = new_ruid = current->uid;
565 old_suid = current->suid;
566 if (capable(CAP_SETUID)) {
567 if (uid != old_ruid && set_user(uid) < 0)
568 return -EAGAIN;
569 current->suid = uid;
570 } else if ((uid != current->uid) && (uid != current->suid))
571 return -EPERM;
572
573 current->fsuid = current->euid = uid;
574
575 if (old_euid != uid)
576 current->dumpable = 0;
577
578 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
579 cap_emulate_setxuid(old_ruid, old_euid, old_suid);
580 }
581
582 return 0;
583 }
584
585
586 /*
587 * This function implements a generic ability to update ruid, euid,
588 * and suid. This allows you to implement the 4.4 compatible seteuid().
589 */
590 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
591 {
592 int old_ruid = current->uid;
593 int old_euid = current->euid;
594 int old_suid = current->suid;
595
596 if (!capable(CAP_SETUID)) {
597 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
598 (ruid != current->euid) && (ruid != current->suid))
599 return -EPERM;
600 if ((euid != (uid_t) -1) && (euid != current->uid) &&
601 (euid != current->euid) && (euid != current->suid))
602 return -EPERM;
603 if ((suid != (uid_t) -1) && (suid != current->uid) &&
604 (suid != current->euid) && (suid != current->suid))
605 return -EPERM;
606 }
607 if (ruid != (uid_t) -1) {
608 if (ruid != current->uid && set_user(ruid) < 0)
609 return -EAGAIN;
610 }
611 if (euid != (uid_t) -1) {
612 if (euid != current->euid)
613 current->dumpable = 0;
614 current->euid = euid;
615 current->fsuid = euid;
616 }
617 if (suid != (uid_t) -1)
618 current->suid = suid;
619
620 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
621 cap_emulate_setxuid(old_ruid, old_euid, old_suid);
622 }
623
624 return 0;
625 }
626
627 asmlinkage long sys_getresuid(uid_t *ruid, uid_t *euid, uid_t *suid)
628 {
629 int retval;
630
631 if (!(retval = put_user(current->uid, ruid)) &&
632 !(retval = put_user(current->euid, euid)))
633 retval = put_user(current->suid, suid);
634
635 return retval;
636 }
637
638 /*
639 * Same as above, but for rgid, egid, sgid.
640 */
641 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
642 {
643 if (!capable(CAP_SETGID)) {
644 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
645 (rgid != current->egid) && (rgid != current->sgid))
646 return -EPERM;
647 if ((egid != (gid_t) -1) && (egid != current->gid) &&
648 (egid != current->egid) && (egid != current->sgid))
649 return -EPERM;
650 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
651 (sgid != current->egid) && (sgid != current->sgid))
652 return -EPERM;
653 }
654 if (rgid != (gid_t) -1)
655 current->gid = rgid;
656 if (egid != (gid_t) -1) {
657 if (egid != current->egid)
658 current->dumpable = 0;
659 current->egid = egid;
660 current->fsgid = egid;
661 }
662 if (sgid != (gid_t) -1)
663 current->sgid = sgid;
664 return 0;
665 }
666
667 asmlinkage long sys_getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid)
668 {
669 int retval;
670
671 if (!(retval = put_user(current->gid, rgid)) &&
672 !(retval = put_user(current->egid, egid)))
673 retval = put_user(current->sgid, sgid);
674
675 return retval;
676 }
677
678
679 /*
680 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
681 * is used for "access()" and for the NFS daemon (letting nfsd stay at
682 * whatever uid it wants to). It normally shadows "euid", except when
683 * explicitly set by setfsuid() or for access..
684 */
685 asmlinkage long sys_setfsuid(uid_t uid)
686 {
687 int old_fsuid;
688
689 old_fsuid = current->fsuid;
690 if (uid == current->uid || uid == current->euid ||
691 uid == current->suid || uid == current->fsuid ||
692 capable(CAP_SETUID))
693 current->fsuid = uid;
694 if (current->fsuid != old_fsuid)
695 current->dumpable = 0;
696
697 /* We emulate fsuid by essentially doing a scaled-down version
698 * of what we did in setresuid and friends. However, we only
699 * operate on the fs-specific bits of the process' effective
700 * capabilities
701 *
702 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
703 * if not, we might be a bit too harsh here.
704 */
705
706 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
707 if (old_fsuid == 0 && current->fsuid != 0) {
708 cap_t(current->cap_effective) &= ~CAP_FS_MASK;
709 }
710 if (old_fsuid != 0 && current->fsuid == 0) {
711 cap_t(current->cap_effective) |=
712 (cap_t(current->cap_permitted) & CAP_FS_MASK);
713 }
714 }
715
716 return old_fsuid;
717 }
718
719 /*
720 * Samma på svenska..
721 */
722 asmlinkage long sys_setfsgid(gid_t gid)
723 {
724 int old_fsgid;
725
726 old_fsgid = current->fsgid;
727 if (gid == current->gid || gid == current->egid ||
728 gid == current->sgid || gid == current->fsgid ||
729 capable(CAP_SETGID))
730 current->fsgid = gid;
731 if (current->fsgid != old_fsgid)
732 current->dumpable = 0;
733
734 return old_fsgid;
735 }
736
737 asmlinkage long sys_times(struct tms * tbuf)
738 {
739 /*
740 * In the SMP world we might just be unlucky and have one of
741 * the times increment as we use it. Since the value is an
742 * atomically safe type this is just fine. Conceptually its
743 * as if the syscall took an instant longer to occur.
744 */
745 if (tbuf)
746 if (copy_to_user(tbuf, ¤t->times, sizeof(struct tms)))
747 return -EFAULT;
748 return jiffies;
749 }
750
751 /*
752 * This needs some heavy checking ...
753 * I just haven't the stomach for it. I also don't fully
754 * understand sessions/pgrp etc. Let somebody who does explain it.
755 *
756 * OK, I think I have the protection semantics right.... this is really
757 * only important on a multi-user system anyway, to make sure one user
758 * can't send a signal to a process owned by another. -TYT, 12/12/91
759 *
760 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
761 * LBT 04.03.94
762 */
763
764 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
765 {
766 struct task_struct * p;
767 int err = -EINVAL;
768
769 if (!pid)
770 pid = current->pid;
771 if (!pgid)
772 pgid = pid;
773 if (pgid < 0)
774 return -EINVAL;
775
776 /* From this point forward we keep holding onto the tasklist lock
777 * so that our parent does not change from under us. -DaveM
778 */
779 read_lock(&tasklist_lock);
780
781 err = -ESRCH;
782 p = find_task_by_pid(pid);
783 if (!p)
784 goto out;
785
786 if (p->p_pptr == current || p->p_opptr == current) {
787 err = -EPERM;
788 if (p->session != current->session)
789 goto out;
790 err = -EACCES;
791 if (p->did_exec)
792 goto out;
793 } else if (p != current)
794 goto out;
795 err = -EPERM;
796 if (p->leader)
797 goto out;
798 if (pgid != pid) {
799 struct task_struct * tmp;
800 for_each_task (tmp) {
801 if (tmp->pgrp == pgid &&
802 tmp->session == current->session)
803 goto ok_pgid;
804 }
805 goto out;
806 }
807
808 ok_pgid:
809 p->pgrp = pgid;
810 err = 0;
811 out:
812 /* All paths lead to here, thus we are safe. -DaveM */
813 read_unlock(&tasklist_lock);
814 return err;
815 }
816
817 asmlinkage long sys_getpgid(pid_t pid)
818 {
819 if (!pid) {
820 return current->pgrp;
821 } else {
822 int retval;
823 struct task_struct *p;
824
825 read_lock(&tasklist_lock);
826 p = find_task_by_pid(pid);
827
828 retval = -ESRCH;
829 if (p)
830 retval = p->pgrp;
831 read_unlock(&tasklist_lock);
832 return retval;
833 }
834 }
835
836 asmlinkage long sys_getpgrp(void)
837 {
838 /* SMP - assuming writes are word atomic this is fine */
839 return current->pgrp;
840 }
841
842 asmlinkage long sys_getsid(pid_t pid)
843 {
844 if (!pid) {
845 return current->session;
846 } else {
847 int retval;
848 struct task_struct *p;
849
850 read_lock(&tasklist_lock);
851 p = find_task_by_pid(pid);
852
853 retval = -ESRCH;
854 if(p)
855 retval = p->session;
856 read_unlock(&tasklist_lock);
857 return retval;
858 }
859 }
860
861 asmlinkage long sys_setsid(void)
862 {
863 struct task_struct * p;
864 int err = -EPERM;
865
866 read_lock(&tasklist_lock);
867 for_each_task(p) {
868 if (p->pgrp == current->pid)
869 goto out;
870 }
871
872 current->leader = 1;
873 current->session = current->pgrp = current->pid;
874 current->tty = NULL;
875 current->tty_old_pgrp = 0;
876 err = current->pgrp;
877 out:
878 read_unlock(&tasklist_lock);
879 return err;
880 }
881
882 /*
883 * Supplementary group IDs
884 */
885 asmlinkage long sys_getgroups(int gidsetsize, gid_t *grouplist)
886 {
887 int i;
888
889 /*
890 * SMP: Nobody else can change our grouplist. Thus we are
891 * safe.
892 */
893
894 if (gidsetsize < 0)
895 return -EINVAL;
896 i = current->ngroups;
897 if (gidsetsize) {
898 if (i > gidsetsize)
899 return -EINVAL;
900 if (copy_to_user(grouplist, current->groups, sizeof(gid_t)*i))
901 return -EFAULT;
902 }
903 return i;
904 }
905
906 /*
907 * SMP: Our groups are not shared. We can copy to/from them safely
908 * without another task interfering.
909 */
910
911 asmlinkage long sys_setgroups(int gidsetsize, gid_t *grouplist)
912 {
913 if (!capable(CAP_SETGID))
914 return -EPERM;
915 if ((unsigned) gidsetsize > NGROUPS)
916 return -EINVAL;
917 if(copy_from_user(current->groups, grouplist, gidsetsize * sizeof(gid_t)))
918 return -EFAULT;
919 current->ngroups = gidsetsize;
920 return 0;
921 }
922
923 static int supplemental_group_member(gid_t grp)
924 {
925 int i = current->ngroups;
926
927 if (i) {
928 gid_t *groups = current->groups;
929 do {
930 if (*groups == grp)
931 return 1;
932 groups++;
933 i--;
934 } while (i);
935 }
936 return 0;
937 }
938
939 /*
940 * Check whether we're fsgid/egid or in the supplemental group..
941 */
942 int in_group_p(gid_t grp)
943 {
944 int retval = 1;
945 if (grp != current->fsgid)
946 retval = supplemental_group_member(grp);
947 return retval;
948 }
949
950 int in_egroup_p(gid_t grp)
951 {
952 int retval = 1;
953 if (grp != current->egid)
954 retval = supplemental_group_member(grp);
955 return retval;
956 }
957
958 DECLARE_RWSEM(uts_sem);
959
960 asmlinkage long sys_newuname(struct new_utsname * name)
961 {
962 int errno = 0;
963
964 down_read(&uts_sem);
965 if (copy_to_user(name,&system_utsname,sizeof *name))
966 errno = -EFAULT;
967 up_read(&uts_sem);
968 return errno;
969 }
970
971 asmlinkage long sys_sethostname(char *name, int len)
972 {
973 int errno;
974
975 if (!capable(CAP_SYS_ADMIN))
976 return -EPERM;
977 if (len < 0 || len > __NEW_UTS_LEN)
978 return -EINVAL;
979 down_write(&uts_sem);
980 errno = -EFAULT;
981 if (!copy_from_user(system_utsname.nodename, name, len)) {
982 system_utsname.nodename[len] = 0;
983 errno = 0;
984 }
985 up_write(&uts_sem);
986 return errno;
987 }
988
989 asmlinkage long sys_gethostname(char *name, int len)
990 {
991 int i, errno;
992
993 if (len < 0)
994 return -EINVAL;
995 down_read(&uts_sem);
996 i = 1 + strlen(system_utsname.nodename);
997 if (i > len)
998 i = len;
999 errno = 0;
1000 if (copy_to_user(name, system_utsname.nodename, i))
1001 errno = -EFAULT;
1002 up_read(&uts_sem);
1003 return errno;
1004 }
1005
1006 /*
1007 * Only setdomainname; getdomainname can be implemented by calling
1008 * uname()
1009 */
1010 asmlinkage long sys_setdomainname(char *name, int len)
1011 {
1012 int errno;
1013
1014 if (!capable(CAP_SYS_ADMIN))
1015 return -EPERM;
1016 if (len < 0 || len > __NEW_UTS_LEN)
1017 return -EINVAL;
1018
1019 down_write(&uts_sem);
1020 errno = -EFAULT;
1021 if (!copy_from_user(system_utsname.domainname, name, len)) {
1022 errno = 0;
1023 system_utsname.domainname[len] = 0;
1024 }
1025 up_write(&uts_sem);
1026 return errno;
1027 }
1028
1029 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit *rlim)
1030 {
1031 if (resource >= RLIM_NLIMITS)
1032 return -EINVAL;
1033 else
1034 return copy_to_user(rlim, current->rlim + resource, sizeof(*rlim))
1035 ? -EFAULT : 0;
1036 }
1037
1038 #if !defined(__ia64__) && !defined(__s390__)
1039
1040 /*
1041 * Back compatibility for getrlimit. Needed for some apps.
1042 */
1043
1044 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit *rlim)
1045 {
1046 struct rlimit x;
1047 if (resource >= RLIM_NLIMITS)
1048 return -EINVAL;
1049
1050 memcpy(&x, current->rlim + resource, sizeof(*rlim));
1051 if(x.rlim_cur > 0x7FFFFFFF)
1052 x.rlim_cur = 0x7FFFFFFF;
1053 if(x.rlim_max > 0x7FFFFFFF)
1054 x.rlim_max = 0x7FFFFFFF;
1055 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1056 }
1057
1058 #endif
1059
1060 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit *rlim)
1061 {
1062 struct rlimit new_rlim, *old_rlim;
1063
1064 if (resource >= RLIM_NLIMITS)
1065 return -EINVAL;
1066 if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1067 return -EFAULT;
1068 if (new_rlim.rlim_cur < 0 || new_rlim.rlim_max < 0)
1069 return -EINVAL;
1070 old_rlim = current->rlim + resource;
1071 if (((new_rlim.rlim_cur > old_rlim->rlim_max) ||
1072 (new_rlim.rlim_max > old_rlim->rlim_max)) &&
1073 !capable(CAP_SYS_RESOURCE))
1074 return -EPERM;
1075 if (resource == RLIMIT_NOFILE) {
1076 if (new_rlim.rlim_cur > NR_OPEN || new_rlim.rlim_max > NR_OPEN)
1077 return -EPERM;
1078 }
1079 *old_rlim = new_rlim;
1080 return 0;
1081 }
1082
1083 /*
1084 * It would make sense to put struct rusage in the task_struct,
1085 * except that would make the task_struct be *really big*. After
1086 * task_struct gets moved into malloc'ed memory, it would
1087 * make sense to do this. It will make moving the rest of the information
1088 * a lot simpler! (Which we're not doing right now because we're not
1089 * measuring them yet).
1090 *
1091 * This is SMP safe. Either we are called from sys_getrusage on ourselves
1092 * below (we know we aren't going to exit/disappear and only we change our
1093 * rusage counters), or we are called from wait4() on a process which is
1094 * either stopped or zombied. In the zombied case the task won't get
1095 * reaped till shortly after the call to getrusage(), in both cases the
1096 * task being examined is in a frozen state so the counters won't change.
1097 *
1098 * FIXME! Get the fault counts properly!
1099 */
1100 int getrusage(struct task_struct *p, int who, struct rusage *ru)
1101 {
1102 struct rusage r;
1103
1104 memset((char *) &r, 0, sizeof(r));
1105 switch (who) {
1106 case RUSAGE_SELF:
1107 r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime);
1108 r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime);
1109 r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime);
1110 r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime);
1111 r.ru_minflt = p->min_flt;
1112 r.ru_majflt = p->maj_flt;
1113 r.ru_nswap = p->nswap;
1114 break;
1115 case RUSAGE_CHILDREN:
1116 r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_cutime);
1117 r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_cutime);
1118 r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_cstime);
1119 r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_cstime);
1120 r.ru_minflt = p->cmin_flt;
1121 r.ru_majflt = p->cmaj_flt;
1122 r.ru_nswap = p->cnswap;
1123 break;
1124 default:
1125 r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime + p->times.tms_cutime);
1126 r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime + p->times.tms_cutime);
1127 r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime + p->times.tms_cstime);
1128 r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime + p->times.tms_cstime);
1129 r.ru_minflt = p->min_flt + p->cmin_flt;
1130 r.ru_majflt = p->maj_flt + p->cmaj_flt;
1131 r.ru_nswap = p->nswap + p->cnswap;
1132 break;
1133 }
1134 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1135 }
1136
1137 asmlinkage long sys_getrusage(int who, struct rusage *ru)
1138 {
1139 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1140 return -EINVAL;
1141 return getrusage(current, who, ru);
1142 }
1143
1144 asmlinkage long sys_umask(int mask)
1145 {
1146 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
1147 return mask;
1148 }
1149
1150 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1151 unsigned long arg4, unsigned long arg5)
1152 {
1153 int error = 0;
1154 int sig;
1155
1156 switch (option) {
1157 case PR_SET_PDEATHSIG:
1158 sig = arg2;
1159 if (sig > _NSIG) {
1160 error = -EINVAL;
1161 break;
1162 }
1163 current->pdeath_signal = sig;
1164 break;
1165 case PR_GET_PDEATHSIG:
1166 error = put_user(current->pdeath_signal, (int *)arg2);
1167 break;
1168 case PR_GET_DUMPABLE:
1169 if (current->dumpable)
1170 error = 1;
1171 break;
1172 case PR_SET_DUMPABLE:
1173 if (arg2 != 0 && arg2 != 1) {
1174 error = -EINVAL;
1175 break;
1176 }
1177 current->dumpable = arg2;
1178 break;
1179 case PR_SET_UNALIGN:
1180 #ifdef SET_UNALIGN_CTL
1181 error = SET_UNALIGN_CTL(current, arg2);
1182 #else
1183 error = -EINVAL;
1184 #endif
1185 break;
1186
1187 case PR_GET_UNALIGN:
1188 #ifdef GET_UNALIGN_CTL
1189 error = GET_UNALIGN_CTL(current, arg2);
1190 #else
1191 error = -EINVAL;
1192 #endif
1193 break;
1194
1195 case PR_GET_KEEPCAPS:
1196 if (current->keep_capabilities)
1197 error = 1;
1198 break;
1199 case PR_SET_KEEPCAPS:
1200 if (arg2 != 0 && arg2 != 1) {
1201 error = -EINVAL;
1202 break;
1203 }
1204 current->keep_capabilities = arg2;
1205 break;
1206 default:
1207 error = -EINVAL;
1208 break;
1209 }
1210 return error;
1211 }
1212
1213 EXPORT_SYMBOL(notifier_chain_register);
1214 EXPORT_SYMBOL(notifier_chain_unregister);
1215 EXPORT_SYMBOL(notifier_call_chain);
1216 EXPORT_SYMBOL(register_reboot_notifier);
1217 EXPORT_SYMBOL(unregister_reboot_notifier);
1218 EXPORT_SYMBOL(in_group_p);
1219 EXPORT_SYMBOL(in_egroup_p);
1220
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