xref: /openbmc/linux/fs/fcntl.c (revision 94c7b6fc) 
1 /*
2  *  linux/fs/fcntl.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 #include <linux/syscalls.h>
8 #include <linux/init.h>
9 #include <linux/mm.h>
10 #include <linux/fs.h>
11 #include <linux/file.h>
12 #include <linux/fdtable.h>
13 #include <linux/capability.h>
14 #include <linux/dnotify.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/pipe_fs_i.h>
18 #include <linux/security.h>
19 #include <linux/ptrace.h>
20 #include <linux/signal.h>
21 #include <linux/rcupdate.h>
22 #include <linux/pid_namespace.h>
23 #include <linux/user_namespace.h>
24 
25 #include <asm/poll.h>
26 #include <asm/siginfo.h>
27 #include <asm/uaccess.h>
28 
29 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
30 
31 static int setfl(int fd, struct file * filp, unsigned long arg)
32 {
33 	struct inode * inode = file_inode(filp);
34 	int error = 0;
35 
36 	/*
37 	 * O_APPEND cannot be cleared if the file is marked as append-only
38 	 * and the file is open for write.
39 	 */
40 	if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
41 		return -EPERM;
42 
43 	/* O_NOATIME can only be set by the owner or superuser */
44 	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
45 		if (!inode_owner_or_capable(inode))
46 			return -EPERM;
47 
48 	/* required for strict SunOS emulation */
49 	if (O_NONBLOCK != O_NDELAY)
50 	       if (arg & O_NDELAY)
51 		   arg |= O_NONBLOCK;
52 
53 	if (arg & O_DIRECT) {
54 		if (!filp->f_mapping || !filp->f_mapping->a_ops ||
55 			!filp->f_mapping->a_ops->direct_IO)
56 				return -EINVAL;
57 	}
58 
59 	if (filp->f_op->check_flags)
60 		error = filp->f_op->check_flags(arg);
61 	if (error)
62 		return error;
63 
64 	/*
65 	 * ->fasync() is responsible for setting the FASYNC bit.
66 	 */
67 	if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
68 		error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
69 		if (error < 0)
70 			goto out;
71 		if (error > 0)
72 			error = 0;
73 	}
74 	spin_lock(&filp->f_lock);
75 	filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
76 	spin_unlock(&filp->f_lock);
77 
78  out:
79 	return error;
80 }
81 
82 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
83                      int force)
84 {
85 	write_lock_irq(&filp->f_owner.lock);
86 	if (force || !filp->f_owner.pid) {
87 		put_pid(filp->f_owner.pid);
88 		filp->f_owner.pid = get_pid(pid);
89 		filp->f_owner.pid_type = type;
90 
91 		if (pid) {
92 			const struct cred *cred = current_cred();
93 			filp->f_owner.uid = cred->uid;
94 			filp->f_owner.euid = cred->euid;
95 		}
96 	}
97 	write_unlock_irq(&filp->f_owner.lock);
98 }
99 
100 int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
101 		int force)
102 {
103 	int err;
104 
105 	err = security_file_set_fowner(filp);
106 	if (err)
107 		return err;
108 
109 	f_modown(filp, pid, type, force);
110 	return 0;
111 }
112 EXPORT_SYMBOL(__f_setown);
113 
114 int f_setown(struct file *filp, unsigned long arg, int force)
115 {
116 	enum pid_type type;
117 	struct pid *pid;
118 	int who = arg;
119 	int result;
120 	type = PIDTYPE_PID;
121 	if (who < 0) {
122 		type = PIDTYPE_PGID;
123 		who = -who;
124 	}
125 	rcu_read_lock();
126 	pid = find_vpid(who);
127 	result = __f_setown(filp, pid, type, force);
128 	rcu_read_unlock();
129 	return result;
130 }
131 EXPORT_SYMBOL(f_setown);
132 
133 void f_delown(struct file *filp)
134 {
135 	f_modown(filp, NULL, PIDTYPE_PID, 1);
136 }
137 
138 pid_t f_getown(struct file *filp)
139 {
140 	pid_t pid;
141 	read_lock(&filp->f_owner.lock);
142 	pid = pid_vnr(filp->f_owner.pid);
143 	if (filp->f_owner.pid_type == PIDTYPE_PGID)
144 		pid = -pid;
145 	read_unlock(&filp->f_owner.lock);
146 	return pid;
147 }
148 
149 static int f_setown_ex(struct file *filp, unsigned long arg)
150 {
151 	struct f_owner_ex __user *owner_p = (void __user *)arg;
152 	struct f_owner_ex owner;
153 	struct pid *pid;
154 	int type;
155 	int ret;
156 
157 	ret = copy_from_user(&owner, owner_p, sizeof(owner));
158 	if (ret)
159 		return -EFAULT;
160 
161 	switch (owner.type) {
162 	case F_OWNER_TID:
163 		type = PIDTYPE_MAX;
164 		break;
165 
166 	case F_OWNER_PID:
167 		type = PIDTYPE_PID;
168 		break;
169 
170 	case F_OWNER_PGRP:
171 		type = PIDTYPE_PGID;
172 		break;
173 
174 	default:
175 		return -EINVAL;
176 	}
177 
178 	rcu_read_lock();
179 	pid = find_vpid(owner.pid);
180 	if (owner.pid && !pid)
181 		ret = -ESRCH;
182 	else
183 		ret = __f_setown(filp, pid, type, 1);
184 	rcu_read_unlock();
185 
186 	return ret;
187 }
188 
189 static int f_getown_ex(struct file *filp, unsigned long arg)
190 {
191 	struct f_owner_ex __user *owner_p = (void __user *)arg;
192 	struct f_owner_ex owner;
193 	int ret = 0;
194 
195 	read_lock(&filp->f_owner.lock);
196 	owner.pid = pid_vnr(filp->f_owner.pid);
197 	switch (filp->f_owner.pid_type) {
198 	case PIDTYPE_MAX:
199 		owner.type = F_OWNER_TID;
200 		break;
201 
202 	case PIDTYPE_PID:
203 		owner.type = F_OWNER_PID;
204 		break;
205 
206 	case PIDTYPE_PGID:
207 		owner.type = F_OWNER_PGRP;
208 		break;
209 
210 	default:
211 		WARN_ON(1);
212 		ret = -EINVAL;
213 		break;
214 	}
215 	read_unlock(&filp->f_owner.lock);
216 
217 	if (!ret) {
218 		ret = copy_to_user(owner_p, &owner, sizeof(owner));
219 		if (ret)
220 			ret = -EFAULT;
221 	}
222 	return ret;
223 }
224 
225 #ifdef CONFIG_CHECKPOINT_RESTORE
226 static int f_getowner_uids(struct file *filp, unsigned long arg)
227 {
228 	struct user_namespace *user_ns = current_user_ns();
229 	uid_t __user *dst = (void __user *)arg;
230 	uid_t src[2];
231 	int err;
232 
233 	read_lock(&filp->f_owner.lock);
234 	src[0] = from_kuid(user_ns, filp->f_owner.uid);
235 	src[1] = from_kuid(user_ns, filp->f_owner.euid);
236 	read_unlock(&filp->f_owner.lock);
237 
238 	err  = put_user(src[0], &dst[0]);
239 	err |= put_user(src[1], &dst[1]);
240 
241 	return err;
242 }
243 #else
244 static int f_getowner_uids(struct file *filp, unsigned long arg)
245 {
246 	return -EINVAL;
247 }
248 #endif
249 
250 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
251 		struct file *filp)
252 {
253 	long err = -EINVAL;
254 
255 	switch (cmd) {
256 	case F_DUPFD:
257 		err = f_dupfd(arg, filp, 0);
258 		break;
259 	case F_DUPFD_CLOEXEC:
260 		err = f_dupfd(arg, filp, O_CLOEXEC);
261 		break;
262 	case F_GETFD:
263 		err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
264 		break;
265 	case F_SETFD:
266 		err = 0;
267 		set_close_on_exec(fd, arg & FD_CLOEXEC);
268 		break;
269 	case F_GETFL:
270 		err = filp->f_flags;
271 		break;
272 	case F_SETFL:
273 		err = setfl(fd, filp, arg);
274 		break;
275 #if BITS_PER_LONG != 32
276 	/* 32-bit arches must use fcntl64() */
277 	case F_OFD_GETLK:
278 #endif
279 	case F_GETLK:
280 		err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
281 		break;
282 #if BITS_PER_LONG != 32
283 	/* 32-bit arches must use fcntl64() */
284 	case F_OFD_SETLK:
285 	case F_OFD_SETLKW:
286 #endif
287 		/* Fallthrough */
288 	case F_SETLK:
289 	case F_SETLKW:
290 		err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
291 		break;
292 	case F_GETOWN:
293 		/*
294 		 * XXX If f_owner is a process group, the
295 		 * negative return value will get converted
296 		 * into an error.  Oops.  If we keep the
297 		 * current syscall conventions, the only way
298 		 * to fix this will be in libc.
299 		 */
300 		err = f_getown(filp);
301 		force_successful_syscall_return();
302 		break;
303 	case F_SETOWN:
304 		err = f_setown(filp, arg, 1);
305 		break;
306 	case F_GETOWN_EX:
307 		err = f_getown_ex(filp, arg);
308 		break;
309 	case F_SETOWN_EX:
310 		err = f_setown_ex(filp, arg);
311 		break;
312 	case F_GETOWNER_UIDS:
313 		err = f_getowner_uids(filp, arg);
314 		break;
315 	case F_GETSIG:
316 		err = filp->f_owner.signum;
317 		break;
318 	case F_SETSIG:
319 		/* arg == 0 restores default behaviour. */
320 		if (!valid_signal(arg)) {
321 			break;
322 		}
323 		err = 0;
324 		filp->f_owner.signum = arg;
325 		break;
326 	case F_GETLEASE:
327 		err = fcntl_getlease(filp);
328 		break;
329 	case F_SETLEASE:
330 		err = fcntl_setlease(fd, filp, arg);
331 		break;
332 	case F_NOTIFY:
333 		err = fcntl_dirnotify(fd, filp, arg);
334 		break;
335 	case F_SETPIPE_SZ:
336 	case F_GETPIPE_SZ:
337 		err = pipe_fcntl(filp, cmd, arg);
338 		break;
339 	default:
340 		break;
341 	}
342 	return err;
343 }
344 
345 static int check_fcntl_cmd(unsigned cmd)
346 {
347 	switch (cmd) {
348 	case F_DUPFD:
349 	case F_DUPFD_CLOEXEC:
350 	case F_GETFD:
351 	case F_SETFD:
352 	case F_GETFL:
353 		return 1;
354 	}
355 	return 0;
356 }
357 
358 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
359 {
360 	struct fd f = fdget_raw(fd);
361 	long err = -EBADF;
362 
363 	if (!f.file)
364 		goto out;
365 
366 	if (unlikely(f.file->f_mode & FMODE_PATH)) {
367 		if (!check_fcntl_cmd(cmd))
368 			goto out1;
369 	}
370 
371 	err = security_file_fcntl(f.file, cmd, arg);
372 	if (!err)
373 		err = do_fcntl(fd, cmd, arg, f.file);
374 
375 out1:
376  	fdput(f);
377 out:
378 	return err;
379 }
380 
381 #if BITS_PER_LONG == 32
382 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
383 		unsigned long, arg)
384 {
385 	struct fd f = fdget_raw(fd);
386 	long err = -EBADF;
387 
388 	if (!f.file)
389 		goto out;
390 
391 	if (unlikely(f.file->f_mode & FMODE_PATH)) {
392 		if (!check_fcntl_cmd(cmd))
393 			goto out1;
394 	}
395 
396 	err = security_file_fcntl(f.file, cmd, arg);
397 	if (err)
398 		goto out1;
399 
400 	switch (cmd) {
401 	case F_GETLK64:
402 	case F_OFD_GETLK:
403 		err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
404 		break;
405 	case F_SETLK64:
406 	case F_SETLKW64:
407 	case F_OFD_SETLK:
408 	case F_OFD_SETLKW:
409 		err = fcntl_setlk64(fd, f.file, cmd,
410 				(struct flock64 __user *) arg);
411 		break;
412 	default:
413 		err = do_fcntl(fd, cmd, arg, f.file);
414 		break;
415 	}
416 out1:
417 	fdput(f);
418 out:
419 	return err;
420 }
421 #endif
422 
423 /* Table to convert sigio signal codes into poll band bitmaps */
424 
425 static const long band_table[NSIGPOLL] = {
426 	POLLIN | POLLRDNORM,			/* POLL_IN */
427 	POLLOUT | POLLWRNORM | POLLWRBAND,	/* POLL_OUT */
428 	POLLIN | POLLRDNORM | POLLMSG,		/* POLL_MSG */
429 	POLLERR,				/* POLL_ERR */
430 	POLLPRI | POLLRDBAND,			/* POLL_PRI */
431 	POLLHUP | POLLERR			/* POLL_HUP */
432 };
433 
434 static inline int sigio_perm(struct task_struct *p,
435                              struct fown_struct *fown, int sig)
436 {
437 	const struct cred *cred;
438 	int ret;
439 
440 	rcu_read_lock();
441 	cred = __task_cred(p);
442 	ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
443 		uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
444 		uid_eq(fown->uid,  cred->suid) || uid_eq(fown->uid,  cred->uid)) &&
445 	       !security_file_send_sigiotask(p, fown, sig));
446 	rcu_read_unlock();
447 	return ret;
448 }
449 
450 static void send_sigio_to_task(struct task_struct *p,
451 			       struct fown_struct *fown,
452 			       int fd, int reason, int group)
453 {
454 	/*
455 	 * F_SETSIG can change ->signum lockless in parallel, make
456 	 * sure we read it once and use the same value throughout.
457 	 */
458 	int signum = ACCESS_ONCE(fown->signum);
459 
460 	if (!sigio_perm(p, fown, signum))
461 		return;
462 
463 	switch (signum) {
464 		siginfo_t si;
465 		default:
466 			/* Queue a rt signal with the appropriate fd as its
467 			   value.  We use SI_SIGIO as the source, not
468 			   SI_KERNEL, since kernel signals always get
469 			   delivered even if we can't queue.  Failure to
470 			   queue in this case _should_ be reported; we fall
471 			   back to SIGIO in that case. --sct */
472 			si.si_signo = signum;
473 			si.si_errno = 0;
474 		        si.si_code  = reason;
475 			/* Make sure we are called with one of the POLL_*
476 			   reasons, otherwise we could leak kernel stack into
477 			   userspace.  */
478 			BUG_ON((reason & __SI_MASK) != __SI_POLL);
479 			if (reason - POLL_IN >= NSIGPOLL)
480 				si.si_band  = ~0L;
481 			else
482 				si.si_band = band_table[reason - POLL_IN];
483 			si.si_fd    = fd;
484 			if (!do_send_sig_info(signum, &si, p, group))
485 				break;
486 		/* fall-through: fall back on the old plain SIGIO signal */
487 		case 0:
488 			do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
489 	}
490 }
491 
492 void send_sigio(struct fown_struct *fown, int fd, int band)
493 {
494 	struct task_struct *p;
495 	enum pid_type type;
496 	struct pid *pid;
497 	int group = 1;
498 
499 	read_lock(&fown->lock);
500 
501 	type = fown->pid_type;
502 	if (type == PIDTYPE_MAX) {
503 		group = 0;
504 		type = PIDTYPE_PID;
505 	}
506 
507 	pid = fown->pid;
508 	if (!pid)
509 		goto out_unlock_fown;
510 
511 	read_lock(&tasklist_lock);
512 	do_each_pid_task(pid, type, p) {
513 		send_sigio_to_task(p, fown, fd, band, group);
514 	} while_each_pid_task(pid, type, p);
515 	read_unlock(&tasklist_lock);
516  out_unlock_fown:
517 	read_unlock(&fown->lock);
518 }
519 
520 static void send_sigurg_to_task(struct task_struct *p,
521 				struct fown_struct *fown, int group)
522 {
523 	if (sigio_perm(p, fown, SIGURG))
524 		do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
525 }
526 
527 int send_sigurg(struct fown_struct *fown)
528 {
529 	struct task_struct *p;
530 	enum pid_type type;
531 	struct pid *pid;
532 	int group = 1;
533 	int ret = 0;
534 
535 	read_lock(&fown->lock);
536 
537 	type = fown->pid_type;
538 	if (type == PIDTYPE_MAX) {
539 		group = 0;
540 		type = PIDTYPE_PID;
541 	}
542 
543 	pid = fown->pid;
544 	if (!pid)
545 		goto out_unlock_fown;
546 
547 	ret = 1;
548 
549 	read_lock(&tasklist_lock);
550 	do_each_pid_task(pid, type, p) {
551 		send_sigurg_to_task(p, fown, group);
552 	} while_each_pid_task(pid, type, p);
553 	read_unlock(&tasklist_lock);
554  out_unlock_fown:
555 	read_unlock(&fown->lock);
556 	return ret;
557 }
558 
559 static DEFINE_SPINLOCK(fasync_lock);
560 static struct kmem_cache *fasync_cache __read_mostly;
561 
562 static void fasync_free_rcu(struct rcu_head *head)
563 {
564 	kmem_cache_free(fasync_cache,
565 			container_of(head, struct fasync_struct, fa_rcu));
566 }
567 
568 /*
569  * Remove a fasync entry. If successfully removed, return
570  * positive and clear the FASYNC flag. If no entry exists,
571  * do nothing and return 0.
572  *
573  * NOTE! It is very important that the FASYNC flag always
574  * match the state "is the filp on a fasync list".
575  *
576  */
577 int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
578 {
579 	struct fasync_struct *fa, **fp;
580 	int result = 0;
581 
582 	spin_lock(&filp->f_lock);
583 	spin_lock(&fasync_lock);
584 	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
585 		if (fa->fa_file != filp)
586 			continue;
587 
588 		spin_lock_irq(&fa->fa_lock);
589 		fa->fa_file = NULL;
590 		spin_unlock_irq(&fa->fa_lock);
591 
592 		*fp = fa->fa_next;
593 		call_rcu(&fa->fa_rcu, fasync_free_rcu);
594 		filp->f_flags &= ~FASYNC;
595 		result = 1;
596 		break;
597 	}
598 	spin_unlock(&fasync_lock);
599 	spin_unlock(&filp->f_lock);
600 	return result;
601 }
602 
603 struct fasync_struct *fasync_alloc(void)
604 {
605 	return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
606 }
607 
608 /*
609  * NOTE! This can be used only for unused fasync entries:
610  * entries that actually got inserted on the fasync list
611  * need to be released by rcu - see fasync_remove_entry.
612  */
613 void fasync_free(struct fasync_struct *new)
614 {
615 	kmem_cache_free(fasync_cache, new);
616 }
617 
618 /*
619  * Insert a new entry into the fasync list.  Return the pointer to the
620  * old one if we didn't use the new one.
621  *
622  * NOTE! It is very important that the FASYNC flag always
623  * match the state "is the filp on a fasync list".
624  */
625 struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
626 {
627         struct fasync_struct *fa, **fp;
628 
629 	spin_lock(&filp->f_lock);
630 	spin_lock(&fasync_lock);
631 	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
632 		if (fa->fa_file != filp)
633 			continue;
634 
635 		spin_lock_irq(&fa->fa_lock);
636 		fa->fa_fd = fd;
637 		spin_unlock_irq(&fa->fa_lock);
638 		goto out;
639 	}
640 
641 	spin_lock_init(&new->fa_lock);
642 	new->magic = FASYNC_MAGIC;
643 	new->fa_file = filp;
644 	new->fa_fd = fd;
645 	new->fa_next = *fapp;
646 	rcu_assign_pointer(*fapp, new);
647 	filp->f_flags |= FASYNC;
648 
649 out:
650 	spin_unlock(&fasync_lock);
651 	spin_unlock(&filp->f_lock);
652 	return fa;
653 }
654 
655 /*
656  * Add a fasync entry. Return negative on error, positive if
657  * added, and zero if did nothing but change an existing one.
658  */
659 static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
660 {
661 	struct fasync_struct *new;
662 
663 	new = fasync_alloc();
664 	if (!new)
665 		return -ENOMEM;
666 
667 	/*
668 	 * fasync_insert_entry() returns the old (update) entry if
669 	 * it existed.
670 	 *
671 	 * So free the (unused) new entry and return 0 to let the
672 	 * caller know that we didn't add any new fasync entries.
673 	 */
674 	if (fasync_insert_entry(fd, filp, fapp, new)) {
675 		fasync_free(new);
676 		return 0;
677 	}
678 
679 	return 1;
680 }
681 
682 /*
683  * fasync_helper() is used by almost all character device drivers
684  * to set up the fasync queue, and for regular files by the file
685  * lease code. It returns negative on error, 0 if it did no changes
686  * and positive if it added/deleted the entry.
687  */
688 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
689 {
690 	if (!on)
691 		return fasync_remove_entry(filp, fapp);
692 	return fasync_add_entry(fd, filp, fapp);
693 }
694 
695 EXPORT_SYMBOL(fasync_helper);
696 
697 /*
698  * rcu_read_lock() is held
699  */
700 static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
701 {
702 	while (fa) {
703 		struct fown_struct *fown;
704 		unsigned long flags;
705 
706 		if (fa->magic != FASYNC_MAGIC) {
707 			printk(KERN_ERR "kill_fasync: bad magic number in "
708 			       "fasync_struct!\n");
709 			return;
710 		}
711 		spin_lock_irqsave(&fa->fa_lock, flags);
712 		if (fa->fa_file) {
713 			fown = &fa->fa_file->f_owner;
714 			/* Don't send SIGURG to processes which have not set a
715 			   queued signum: SIGURG has its own default signalling
716 			   mechanism. */
717 			if (!(sig == SIGURG && fown->signum == 0))
718 				send_sigio(fown, fa->fa_fd, band);
719 		}
720 		spin_unlock_irqrestore(&fa->fa_lock, flags);
721 		fa = rcu_dereference(fa->fa_next);
722 	}
723 }
724 
725 void kill_fasync(struct fasync_struct **fp, int sig, int band)
726 {
727 	/* First a quick test without locking: usually
728 	 * the list is empty.
729 	 */
730 	if (*fp) {
731 		rcu_read_lock();
732 		kill_fasync_rcu(rcu_dereference(*fp), sig, band);
733 		rcu_read_unlock();
734 	}
735 }
736 EXPORT_SYMBOL(kill_fasync);
737 
738 static int __init fcntl_init(void)
739 {
740 	/*
741 	 * Please add new bits here to ensure allocation uniqueness.
742 	 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
743 	 * is defined as O_NONBLOCK on some platforms and not on others.
744 	 */
745 	BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
746 		O_RDONLY	| O_WRONLY	| O_RDWR	|
747 		O_CREAT		| O_EXCL	| O_NOCTTY	|
748 		O_TRUNC		| O_APPEND	| /* O_NONBLOCK	| */
749 		__O_SYNC	| O_DSYNC	| FASYNC	|
750 		O_DIRECT	| O_LARGEFILE	| O_DIRECTORY	|
751 		O_NOFOLLOW	| O_NOATIME	| O_CLOEXEC	|
752 		__FMODE_EXEC	| O_PATH	| __O_TMPFILE
753 		));
754 
755 	fasync_cache = kmem_cache_create("fasync_cache",
756 		sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
757 	return 0;
758 }
759 
760 module_init(fcntl_init)
761