can: Fix raw_getname() leak
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / read_write.c
blob0619b2ae7923021c12da3d50b048be5e19c2e068
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 SYSCALL_DEFINE3(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 SYSCALL_DEFINE5(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 SYSCALL_DEFINE3(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 SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
355 size_t, count)
357 struct file *file;
358 ssize_t ret = -EBADF;
359 int fput_needed;
361 file = fget_light(fd, &fput_needed);
362 if (file) {
363 loff_t pos = file_pos_read(file);
364 ret = vfs_write(file, buf, count, &pos);
365 file_pos_write(file, pos);
366 fput_light(file, fput_needed);
369 return ret;
372 SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf,
373 size_t count, loff_t pos)
375 struct file *file;
376 ssize_t ret = -EBADF;
377 int fput_needed;
379 if (pos < 0)
380 return -EINVAL;
382 file = fget_light(fd, &fput_needed);
383 if (file) {
384 ret = -ESPIPE;
385 if (file->f_mode & FMODE_PREAD)
386 ret = vfs_read(file, buf, count, &pos);
387 fput_light(file, fput_needed);
390 return ret;
392 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
393 asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos)
395 return SYSC_pread64((unsigned int) fd, (char __user *) buf,
396 (size_t) count, pos);
398 SYSCALL_ALIAS(sys_pread64, SyS_pread64);
399 #endif
401 SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf,
402 size_t count, loff_t pos)
404 struct file *file;
405 ssize_t ret = -EBADF;
406 int fput_needed;
408 if (pos < 0)
409 return -EINVAL;
411 file = fget_light(fd, &fput_needed);
412 if (file) {
413 ret = -ESPIPE;
414 if (file->f_mode & FMODE_PWRITE)
415 ret = vfs_write(file, buf, count, &pos);
416 fput_light(file, fput_needed);
419 return ret;
421 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
422 asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos)
424 return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf,
425 (size_t) count, pos);
427 SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64);
428 #endif
431 * Reduce an iovec's length in-place. Return the resulting number of segments
433 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
435 unsigned long seg = 0;
436 size_t len = 0;
438 while (seg < nr_segs) {
439 seg++;
440 if (len + iov->iov_len >= to) {
441 iov->iov_len = to - len;
442 break;
444 len += iov->iov_len;
445 iov++;
447 return seg;
449 EXPORT_SYMBOL(iov_shorten);
451 ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
452 unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
454 struct kiocb kiocb;
455 ssize_t ret;
457 init_sync_kiocb(&kiocb, filp);
458 kiocb.ki_pos = *ppos;
459 kiocb.ki_left = len;
460 kiocb.ki_nbytes = len;
462 for (;;) {
463 ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
464 if (ret != -EIOCBRETRY)
465 break;
466 wait_on_retry_sync_kiocb(&kiocb);
469 if (ret == -EIOCBQUEUED)
470 ret = wait_on_sync_kiocb(&kiocb);
471 *ppos = kiocb.ki_pos;
472 return ret;
475 /* Do it by hand, with file-ops */
476 ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
477 unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
479 struct iovec *vector = iov;
480 ssize_t ret = 0;
482 while (nr_segs > 0) {
483 void __user *base;
484 size_t len;
485 ssize_t nr;
487 base = vector->iov_base;
488 len = vector->iov_len;
489 vector++;
490 nr_segs--;
492 nr = fn(filp, base, len, ppos);
494 if (nr < 0) {
495 if (!ret)
496 ret = nr;
497 break;
499 ret += nr;
500 if (nr != len)
501 break;
504 return ret;
507 /* A write operation does a read from user space and vice versa */
508 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
510 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
511 unsigned long nr_segs, unsigned long fast_segs,
512 struct iovec *fast_pointer,
513 struct iovec **ret_pointer)
515 unsigned long seg;
516 ssize_t ret;
517 struct iovec *iov = fast_pointer;
520 * SuS says "The readv() function *may* fail if the iovcnt argument
521 * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
522 * traditionally returned zero for zero segments, so...
524 if (nr_segs == 0) {
525 ret = 0;
526 goto out;
530 * First get the "struct iovec" from user memory and
531 * verify all the pointers
533 if (nr_segs > UIO_MAXIOV) {
534 ret = -EINVAL;
535 goto out;
537 if (nr_segs > fast_segs) {
538 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
539 if (iov == NULL) {
540 ret = -ENOMEM;
541 goto out;
544 if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
545 ret = -EFAULT;
546 goto out;
550 * According to the Single Unix Specification we should return EINVAL
551 * if an element length is < 0 when cast to ssize_t or if the
552 * total length would overflow the ssize_t return value of the
553 * system call.
555 ret = 0;
556 for (seg = 0; seg < nr_segs; seg++) {
557 void __user *buf = iov[seg].iov_base;
558 ssize_t len = (ssize_t)iov[seg].iov_len;
560 /* see if we we're about to use an invalid len or if
561 * it's about to overflow ssize_t */
562 if (len < 0 || (ret + len < ret)) {
563 ret = -EINVAL;
564 goto out;
566 if (unlikely(!access_ok(vrfy_dir(type), buf, len))) {
567 ret = -EFAULT;
568 goto out;
571 ret += len;
573 out:
574 *ret_pointer = iov;
575 return ret;
578 static ssize_t do_readv_writev(int type, struct file *file,
579 const struct iovec __user * uvector,
580 unsigned long nr_segs, loff_t *pos)
582 size_t tot_len;
583 struct iovec iovstack[UIO_FASTIOV];
584 struct iovec *iov = iovstack;
585 ssize_t ret;
586 io_fn_t fn;
587 iov_fn_t fnv;
589 if (!file->f_op) {
590 ret = -EINVAL;
591 goto out;
594 ret = rw_copy_check_uvector(type, uvector, nr_segs,
595 ARRAY_SIZE(iovstack), iovstack, &iov);
596 if (ret <= 0)
597 goto out;
599 tot_len = ret;
600 ret = rw_verify_area(type, file, pos, tot_len);
601 if (ret < 0)
602 goto out;
604 fnv = NULL;
605 if (type == READ) {
606 fn = file->f_op->read;
607 fnv = file->f_op->aio_read;
608 } else {
609 fn = (io_fn_t)file->f_op->write;
610 fnv = file->f_op->aio_write;
613 if (fnv)
614 ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
615 pos, fnv);
616 else
617 ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
619 out:
620 if (iov != iovstack)
621 kfree(iov);
622 if ((ret + (type == READ)) > 0) {
623 if (type == READ)
624 fsnotify_access(file->f_path.dentry);
625 else
626 fsnotify_modify(file->f_path.dentry);
628 return ret;
631 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
632 unsigned long vlen, loff_t *pos)
634 if (!(file->f_mode & FMODE_READ))
635 return -EBADF;
636 if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
637 return -EINVAL;
639 return do_readv_writev(READ, file, vec, vlen, pos);
642 EXPORT_SYMBOL(vfs_readv);
644 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
645 unsigned long vlen, loff_t *pos)
647 if (!(file->f_mode & FMODE_WRITE))
648 return -EBADF;
649 if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
650 return -EINVAL;
652 return do_readv_writev(WRITE, file, vec, vlen, pos);
655 EXPORT_SYMBOL(vfs_writev);
657 SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
658 unsigned long, vlen)
660 struct file *file;
661 ssize_t ret = -EBADF;
662 int fput_needed;
664 file = fget_light(fd, &fput_needed);
665 if (file) {
666 loff_t pos = file_pos_read(file);
667 ret = vfs_readv(file, vec, vlen, &pos);
668 file_pos_write(file, pos);
669 fput_light(file, fput_needed);
672 if (ret > 0)
673 add_rchar(current, ret);
674 inc_syscr(current);
675 return ret;
678 SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
679 unsigned long, vlen)
681 struct file *file;
682 ssize_t ret = -EBADF;
683 int fput_needed;
685 file = fget_light(fd, &fput_needed);
686 if (file) {
687 loff_t pos = file_pos_read(file);
688 ret = vfs_writev(file, vec, vlen, &pos);
689 file_pos_write(file, pos);
690 fput_light(file, fput_needed);
693 if (ret > 0)
694 add_wchar(current, ret);
695 inc_syscw(current);
696 return ret;
699 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
700 size_t count, loff_t max)
702 struct file * in_file, * out_file;
703 struct inode * in_inode, * out_inode;
704 loff_t pos;
705 ssize_t retval;
706 int fput_needed_in, fput_needed_out, fl;
709 * Get input file, and verify that it is ok..
711 retval = -EBADF;
712 in_file = fget_light(in_fd, &fput_needed_in);
713 if (!in_file)
714 goto out;
715 if (!(in_file->f_mode & FMODE_READ))
716 goto fput_in;
717 retval = -EINVAL;
718 in_inode = in_file->f_path.dentry->d_inode;
719 if (!in_inode)
720 goto fput_in;
721 if (!in_file->f_op || !in_file->f_op->splice_read)
722 goto fput_in;
723 retval = -ESPIPE;
724 if (!ppos)
725 ppos = &in_file->f_pos;
726 else
727 if (!(in_file->f_mode & FMODE_PREAD))
728 goto fput_in;
729 retval = rw_verify_area(READ, in_file, ppos, count);
730 if (retval < 0)
731 goto fput_in;
732 count = retval;
735 * Get output file, and verify that it is ok..
737 retval = -EBADF;
738 out_file = fget_light(out_fd, &fput_needed_out);
739 if (!out_file)
740 goto fput_in;
741 if (!(out_file->f_mode & FMODE_WRITE))
742 goto fput_out;
743 retval = -EINVAL;
744 if (!out_file->f_op || !out_file->f_op->sendpage)
745 goto fput_out;
746 out_inode = out_file->f_path.dentry->d_inode;
747 retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
748 if (retval < 0)
749 goto fput_out;
750 count = retval;
752 if (!max)
753 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
755 pos = *ppos;
756 retval = -EINVAL;
757 if (unlikely(pos < 0))
758 goto fput_out;
759 if (unlikely(pos + count > max)) {
760 retval = -EOVERFLOW;
761 if (pos >= max)
762 goto fput_out;
763 count = max - pos;
766 fl = 0;
767 #if 0
769 * We need to debate whether we can enable this or not. The
770 * man page documents EAGAIN return for the output at least,
771 * and the application is arguably buggy if it doesn't expect
772 * EAGAIN on a non-blocking file descriptor.
774 if (in_file->f_flags & O_NONBLOCK)
775 fl = SPLICE_F_NONBLOCK;
776 #endif
777 retval = do_splice_direct(in_file, ppos, out_file, count, fl);
779 if (retval > 0) {
780 add_rchar(current, retval);
781 add_wchar(current, retval);
784 inc_syscr(current);
785 inc_syscw(current);
786 if (*ppos > max)
787 retval = -EOVERFLOW;
789 fput_out:
790 fput_light(out_file, fput_needed_out);
791 fput_in:
792 fput_light(in_file, fput_needed_in);
793 out:
794 return retval;
797 SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
799 loff_t pos;
800 off_t off;
801 ssize_t ret;
803 if (offset) {
804 if (unlikely(get_user(off, offset)))
805 return -EFAULT;
806 pos = off;
807 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
808 if (unlikely(put_user(pos, offset)))
809 return -EFAULT;
810 return ret;
813 return do_sendfile(out_fd, in_fd, NULL, count, 0);
816 SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
818 loff_t pos;
819 ssize_t ret;
821 if (offset) {
822 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
823 return -EFAULT;
824 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
825 if (unlikely(put_user(pos, offset)))
826 return -EFAULT;
827 return ret;
830 return do_sendfile(out_fd, in_fd, NULL, count, 0);