genirq: better warning on irqchip->set_type() failure
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / read_write.c
blob9ba495d5a29b26d9493eea556ccd0992deb68829
1 /*
2 * linux/fs/read_write.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
7 #include <linux/slab.h>
8 #include <linux/stat.h>
9 #include <linux/fcntl.h>
10 #include <linux/file.h>
11 #include <linux/uio.h>
12 #include <linux/smp_lock.h>
13 #include <linux/fsnotify.h>
14 #include <linux/security.h>
15 #include <linux/module.h>
16 #include <linux/syscalls.h>
17 #include <linux/pagemap.h>
18 #include <linux/splice.h>
19 #include "read_write.h"
21 #include <asm/uaccess.h>
22 #include <asm/unistd.h>
24 const struct file_operations generic_ro_fops = {
25 .llseek = generic_file_llseek,
26 .read = do_sync_read,
27 .aio_read = generic_file_aio_read,
28 .mmap = generic_file_readonly_mmap,
29 .splice_read = generic_file_splice_read,
32 EXPORT_SYMBOL(generic_ro_fops);
34 loff_t
35 generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
37 loff_t retval;
38 struct inode *inode = file->f_mapping->host;
40 switch (origin) {
41 case SEEK_END:
42 offset += inode->i_size;
43 break;
44 case SEEK_CUR:
45 offset += file->f_pos;
47 retval = -EINVAL;
48 if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
49 /* Special lock needed here? */
50 if (offset != file->f_pos) {
51 file->f_pos = offset;
52 file->f_version = 0;
54 retval = offset;
56 return retval;
58 EXPORT_SYMBOL(generic_file_llseek_unlocked);
60 loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
62 loff_t n;
63 mutex_lock(&file->f_dentry->d_inode->i_mutex);
64 n = generic_file_llseek_unlocked(file, offset, origin);
65 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
66 return n;
68 EXPORT_SYMBOL(generic_file_llseek);
70 loff_t no_llseek(struct file *file, loff_t offset, int origin)
72 return -ESPIPE;
74 EXPORT_SYMBOL(no_llseek);
76 loff_t default_llseek(struct file *file, loff_t offset, int origin)
78 loff_t retval;
80 lock_kernel();
81 switch (origin) {
82 case SEEK_END:
83 offset += i_size_read(file->f_path.dentry->d_inode);
84 break;
85 case SEEK_CUR:
86 offset += file->f_pos;
88 retval = -EINVAL;
89 if (offset >= 0) {
90 if (offset != file->f_pos) {
91 file->f_pos = offset;
92 file->f_version = 0;
94 retval = offset;
96 unlock_kernel();
97 return retval;
99 EXPORT_SYMBOL(default_llseek);
101 loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
103 loff_t (*fn)(struct file *, loff_t, int);
105 fn = no_llseek;
106 if (file->f_mode & FMODE_LSEEK) {
107 fn = default_llseek;
108 if (file->f_op && file->f_op->llseek)
109 fn = file->f_op->llseek;
111 return fn(file, offset, origin);
113 EXPORT_SYMBOL(vfs_llseek);
115 asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
117 off_t retval;
118 struct file * file;
119 int fput_needed;
121 retval = -EBADF;
122 file = fget_light(fd, &fput_needed);
123 if (!file)
124 goto bad;
126 retval = -EINVAL;
127 if (origin <= SEEK_MAX) {
128 loff_t res = vfs_llseek(file, offset, origin);
129 retval = res;
130 if (res != (loff_t)retval)
131 retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
133 fput_light(file, fput_needed);
134 bad:
135 return retval;
138 #ifdef __ARCH_WANT_SYS_LLSEEK
139 asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
140 unsigned long offset_low, loff_t __user * result,
141 unsigned int origin)
143 int retval;
144 struct file * file;
145 loff_t offset;
146 int fput_needed;
148 retval = -EBADF;
149 file = fget_light(fd, &fput_needed);
150 if (!file)
151 goto bad;
153 retval = -EINVAL;
154 if (origin > SEEK_MAX)
155 goto out_putf;
157 offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
158 origin);
160 retval = (int)offset;
161 if (offset >= 0) {
162 retval = -EFAULT;
163 if (!copy_to_user(result, &offset, sizeof(offset)))
164 retval = 0;
166 out_putf:
167 fput_light(file, fput_needed);
168 bad:
169 return retval;
171 #endif
174 * rw_verify_area doesn't like huge counts. We limit
175 * them to something that fits in "int" so that others
176 * won't have to do range checks all the time.
178 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
180 int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
182 struct inode *inode;
183 loff_t pos;
184 int retval = -EINVAL;
186 inode = file->f_path.dentry->d_inode;
187 if (unlikely((ssize_t) count < 0))
188 return retval;
189 pos = *ppos;
190 if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
191 return retval;
193 if (unlikely(inode->i_flock && mandatory_lock(inode))) {
194 retval = locks_mandatory_area(
195 read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
196 inode, file, pos, count);
197 if (retval < 0)
198 return retval;
200 retval = security_file_permission(file,
201 read_write == READ ? MAY_READ : MAY_WRITE);
202 if (retval)
203 return retval;
204 return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
207 static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
209 set_current_state(TASK_UNINTERRUPTIBLE);
210 if (!kiocbIsKicked(iocb))
211 schedule();
212 else
213 kiocbClearKicked(iocb);
214 __set_current_state(TASK_RUNNING);
217 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
219 struct iovec iov = { .iov_base = buf, .iov_len = len };
220 struct kiocb kiocb;
221 ssize_t ret;
223 init_sync_kiocb(&kiocb, filp);
224 kiocb.ki_pos = *ppos;
225 kiocb.ki_left = len;
227 for (;;) {
228 ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
229 if (ret != -EIOCBRETRY)
230 break;
231 wait_on_retry_sync_kiocb(&kiocb);
234 if (-EIOCBQUEUED == ret)
235 ret = wait_on_sync_kiocb(&kiocb);
236 *ppos = kiocb.ki_pos;
237 return ret;
240 EXPORT_SYMBOL(do_sync_read);
242 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
244 ssize_t ret;
246 if (!(file->f_mode & FMODE_READ))
247 return -EBADF;
248 if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
249 return -EINVAL;
250 if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
251 return -EFAULT;
253 ret = rw_verify_area(READ, file, pos, count);
254 if (ret >= 0) {
255 count = ret;
256 if (file->f_op->read)
257 ret = file->f_op->read(file, buf, count, pos);
258 else
259 ret = do_sync_read(file, buf, count, pos);
260 if (ret > 0) {
261 fsnotify_access(file->f_path.dentry);
262 add_rchar(current, ret);
264 inc_syscr(current);
267 return ret;
270 EXPORT_SYMBOL(vfs_read);
272 ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
274 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
275 struct kiocb kiocb;
276 ssize_t ret;
278 init_sync_kiocb(&kiocb, filp);
279 kiocb.ki_pos = *ppos;
280 kiocb.ki_left = len;
282 for (;;) {
283 ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
284 if (ret != -EIOCBRETRY)
285 break;
286 wait_on_retry_sync_kiocb(&kiocb);
289 if (-EIOCBQUEUED == ret)
290 ret = wait_on_sync_kiocb(&kiocb);
291 *ppos = kiocb.ki_pos;
292 return ret;
295 EXPORT_SYMBOL(do_sync_write);
297 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
299 ssize_t ret;
301 if (!(file->f_mode & FMODE_WRITE))
302 return -EBADF;
303 if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
304 return -EINVAL;
305 if (unlikely(!access_ok(VERIFY_READ, buf, count)))
306 return -EFAULT;
308 ret = rw_verify_area(WRITE, file, pos, count);
309 if (ret >= 0) {
310 count = ret;
311 if (file->f_op->write)
312 ret = file->f_op->write(file, buf, count, pos);
313 else
314 ret = do_sync_write(file, buf, count, pos);
315 if (ret > 0) {
316 fsnotify_modify(file->f_path.dentry);
317 add_wchar(current, ret);
319 inc_syscw(current);
322 return ret;
325 EXPORT_SYMBOL(vfs_write);
327 static inline loff_t file_pos_read(struct file *file)
329 return file->f_pos;
332 static inline void file_pos_write(struct file *file, loff_t pos)
334 file->f_pos = pos;
337 asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
339 struct file *file;
340 ssize_t ret = -EBADF;
341 int fput_needed;
343 file = fget_light(fd, &fput_needed);
344 if (file) {
345 loff_t pos = file_pos_read(file);
346 ret = vfs_read(file, buf, count, &pos);
347 file_pos_write(file, pos);
348 fput_light(file, fput_needed);
351 return ret;
354 asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
356 struct file *file;
357 ssize_t ret = -EBADF;
358 int fput_needed;
360 file = fget_light(fd, &fput_needed);
361 if (file) {
362 loff_t pos = file_pos_read(file);
363 ret = vfs_write(file, buf, count, &pos);
364 file_pos_write(file, pos);
365 fput_light(file, fput_needed);
368 return ret;
371 asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
372 size_t count, loff_t pos)
374 struct file *file;
375 ssize_t ret = -EBADF;
376 int fput_needed;
378 if (pos < 0)
379 return -EINVAL;
381 file = fget_light(fd, &fput_needed);
382 if (file) {
383 ret = -ESPIPE;
384 if (file->f_mode & FMODE_PREAD)
385 ret = vfs_read(file, buf, count, &pos);
386 fput_light(file, fput_needed);
389 return ret;
392 asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
393 size_t count, loff_t pos)
395 struct file *file;
396 ssize_t ret = -EBADF;
397 int fput_needed;
399 if (pos < 0)
400 return -EINVAL;
402 file = fget_light(fd, &fput_needed);
403 if (file) {
404 ret = -ESPIPE;
405 if (file->f_mode & FMODE_PWRITE)
406 ret = vfs_write(file, buf, count, &pos);
407 fput_light(file, fput_needed);
410 return ret;
414 * Reduce an iovec's length in-place. Return the resulting number of segments
416 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
418 unsigned long seg = 0;
419 size_t len = 0;
421 while (seg < nr_segs) {
422 seg++;
423 if (len + iov->iov_len >= to) {
424 iov->iov_len = to - len;
425 break;
427 len += iov->iov_len;
428 iov++;
430 return seg;
432 EXPORT_SYMBOL(iov_shorten);
434 ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
435 unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
437 struct kiocb kiocb;
438 ssize_t ret;
440 init_sync_kiocb(&kiocb, filp);
441 kiocb.ki_pos = *ppos;
442 kiocb.ki_left = len;
443 kiocb.ki_nbytes = len;
445 for (;;) {
446 ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
447 if (ret != -EIOCBRETRY)
448 break;
449 wait_on_retry_sync_kiocb(&kiocb);
452 if (ret == -EIOCBQUEUED)
453 ret = wait_on_sync_kiocb(&kiocb);
454 *ppos = kiocb.ki_pos;
455 return ret;
458 /* Do it by hand, with file-ops */
459 ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
460 unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
462 struct iovec *vector = iov;
463 ssize_t ret = 0;
465 while (nr_segs > 0) {
466 void __user *base;
467 size_t len;
468 ssize_t nr;
470 base = vector->iov_base;
471 len = vector->iov_len;
472 vector++;
473 nr_segs--;
475 nr = fn(filp, base, len, ppos);
477 if (nr < 0) {
478 if (!ret)
479 ret = nr;
480 break;
482 ret += nr;
483 if (nr != len)
484 break;
487 return ret;
490 /* A write operation does a read from user space and vice versa */
491 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
493 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
494 unsigned long nr_segs, unsigned long fast_segs,
495 struct iovec *fast_pointer,
496 struct iovec **ret_pointer)
498 unsigned long seg;
499 ssize_t ret;
500 struct iovec *iov = fast_pointer;
503 * SuS says "The readv() function *may* fail if the iovcnt argument
504 * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
505 * traditionally returned zero for zero segments, so...
507 if (nr_segs == 0) {
508 ret = 0;
509 goto out;
513 * First get the "struct iovec" from user memory and
514 * verify all the pointers
516 if (nr_segs > UIO_MAXIOV) {
517 ret = -EINVAL;
518 goto out;
520 if (nr_segs > fast_segs) {
521 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
522 if (iov == NULL) {
523 ret = -ENOMEM;
524 goto out;
527 if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
528 ret = -EFAULT;
529 goto out;
533 * According to the Single Unix Specification we should return EINVAL
534 * if an element length is < 0 when cast to ssize_t or if the
535 * total length would overflow the ssize_t return value of the
536 * system call.
538 ret = 0;
539 for (seg = 0; seg < nr_segs; seg++) {
540 void __user *buf = iov[seg].iov_base;
541 ssize_t len = (ssize_t)iov[seg].iov_len;
543 /* see if we we're about to use an invalid len or if
544 * it's about to overflow ssize_t */
545 if (len < 0 || (ret + len < ret)) {
546 ret = -EINVAL;
547 goto out;
549 if (unlikely(!access_ok(vrfy_dir(type), buf, len))) {
550 ret = -EFAULT;
551 goto out;
554 ret += len;
556 out:
557 *ret_pointer = iov;
558 return ret;
561 static ssize_t do_readv_writev(int type, struct file *file,
562 const struct iovec __user * uvector,
563 unsigned long nr_segs, loff_t *pos)
565 size_t tot_len;
566 struct iovec iovstack[UIO_FASTIOV];
567 struct iovec *iov = iovstack;
568 ssize_t ret;
569 io_fn_t fn;
570 iov_fn_t fnv;
572 if (!file->f_op) {
573 ret = -EINVAL;
574 goto out;
577 ret = rw_copy_check_uvector(type, uvector, nr_segs,
578 ARRAY_SIZE(iovstack), iovstack, &iov);
579 if (ret <= 0)
580 goto out;
582 tot_len = ret;
583 ret = rw_verify_area(type, file, pos, tot_len);
584 if (ret < 0)
585 goto out;
587 fnv = NULL;
588 if (type == READ) {
589 fn = file->f_op->read;
590 fnv = file->f_op->aio_read;
591 } else {
592 fn = (io_fn_t)file->f_op->write;
593 fnv = file->f_op->aio_write;
596 if (fnv)
597 ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
598 pos, fnv);
599 else
600 ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
602 out:
603 if (iov != iovstack)
604 kfree(iov);
605 if ((ret + (type == READ)) > 0) {
606 if (type == READ)
607 fsnotify_access(file->f_path.dentry);
608 else
609 fsnotify_modify(file->f_path.dentry);
611 return ret;
614 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
615 unsigned long vlen, loff_t *pos)
617 if (!(file->f_mode & FMODE_READ))
618 return -EBADF;
619 if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
620 return -EINVAL;
622 return do_readv_writev(READ, file, vec, vlen, pos);
625 EXPORT_SYMBOL(vfs_readv);
627 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
628 unsigned long vlen, loff_t *pos)
630 if (!(file->f_mode & FMODE_WRITE))
631 return -EBADF;
632 if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
633 return -EINVAL;
635 return do_readv_writev(WRITE, file, vec, vlen, pos);
638 EXPORT_SYMBOL(vfs_writev);
640 asmlinkage ssize_t
641 sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
643 struct file *file;
644 ssize_t ret = -EBADF;
645 int fput_needed;
647 file = fget_light(fd, &fput_needed);
648 if (file) {
649 loff_t pos = file_pos_read(file);
650 ret = vfs_readv(file, vec, vlen, &pos);
651 file_pos_write(file, pos);
652 fput_light(file, fput_needed);
655 if (ret > 0)
656 add_rchar(current, ret);
657 inc_syscr(current);
658 return ret;
661 asmlinkage ssize_t
662 sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
664 struct file *file;
665 ssize_t ret = -EBADF;
666 int fput_needed;
668 file = fget_light(fd, &fput_needed);
669 if (file) {
670 loff_t pos = file_pos_read(file);
671 ret = vfs_writev(file, vec, vlen, &pos);
672 file_pos_write(file, pos);
673 fput_light(file, fput_needed);
676 if (ret > 0)
677 add_wchar(current, ret);
678 inc_syscw(current);
679 return ret;
682 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
683 size_t count, loff_t max)
685 struct file * in_file, * out_file;
686 struct inode * in_inode, * out_inode;
687 loff_t pos;
688 ssize_t retval;
689 int fput_needed_in, fput_needed_out, fl;
692 * Get input file, and verify that it is ok..
694 retval = -EBADF;
695 in_file = fget_light(in_fd, &fput_needed_in);
696 if (!in_file)
697 goto out;
698 if (!(in_file->f_mode & FMODE_READ))
699 goto fput_in;
700 retval = -EINVAL;
701 in_inode = in_file->f_path.dentry->d_inode;
702 if (!in_inode)
703 goto fput_in;
704 if (!in_file->f_op || !in_file->f_op->splice_read)
705 goto fput_in;
706 retval = -ESPIPE;
707 if (!ppos)
708 ppos = &in_file->f_pos;
709 else
710 if (!(in_file->f_mode & FMODE_PREAD))
711 goto fput_in;
712 retval = rw_verify_area(READ, in_file, ppos, count);
713 if (retval < 0)
714 goto fput_in;
715 count = retval;
718 * Get output file, and verify that it is ok..
720 retval = -EBADF;
721 out_file = fget_light(out_fd, &fput_needed_out);
722 if (!out_file)
723 goto fput_in;
724 if (!(out_file->f_mode & FMODE_WRITE))
725 goto fput_out;
726 retval = -EINVAL;
727 if (!out_file->f_op || !out_file->f_op->sendpage)
728 goto fput_out;
729 out_inode = out_file->f_path.dentry->d_inode;
730 retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
731 if (retval < 0)
732 goto fput_out;
733 count = retval;
735 if (!max)
736 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
738 pos = *ppos;
739 retval = -EINVAL;
740 if (unlikely(pos < 0))
741 goto fput_out;
742 if (unlikely(pos + count > max)) {
743 retval = -EOVERFLOW;
744 if (pos >= max)
745 goto fput_out;
746 count = max - pos;
749 fl = 0;
750 #if 0
752 * We need to debate whether we can enable this or not. The
753 * man page documents EAGAIN return for the output at least,
754 * and the application is arguably buggy if it doesn't expect
755 * EAGAIN on a non-blocking file descriptor.
757 if (in_file->f_flags & O_NONBLOCK)
758 fl = SPLICE_F_NONBLOCK;
759 #endif
760 retval = do_splice_direct(in_file, ppos, out_file, count, fl);
762 if (retval > 0) {
763 add_rchar(current, retval);
764 add_wchar(current, retval);
767 inc_syscr(current);
768 inc_syscw(current);
769 if (*ppos > max)
770 retval = -EOVERFLOW;
772 fput_out:
773 fput_light(out_file, fput_needed_out);
774 fput_in:
775 fput_light(in_file, fput_needed_in);
776 out:
777 return retval;
780 asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
782 loff_t pos;
783 off_t off;
784 ssize_t ret;
786 if (offset) {
787 if (unlikely(get_user(off, offset)))
788 return -EFAULT;
789 pos = off;
790 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
791 if (unlikely(put_user(pos, offset)))
792 return -EFAULT;
793 return ret;
796 return do_sendfile(out_fd, in_fd, NULL, count, 0);
799 asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
801 loff_t pos;
802 ssize_t ret;
804 if (offset) {
805 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
806 return -EFAULT;
807 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
808 if (unlikely(put_user(pos, offset)))
809 return -EFAULT;
810 return ret;
813 return do_sendfile(out_fd, in_fd, NULL, count, 0);