2 * linux/fs/read_write.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
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/fsnotify.h>
13 #include <linux/security.h>
14 #include <linux/export.h>
15 #include <linux/syscalls.h>
16 #include <linux/pagemap.h>
17 #include <linux/splice.h>
18 #include <linux/compat.h>
21 #include <asm/uaccess.h>
22 #include <asm/unistd.h>
24 typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
25 typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *);
27 const struct file_operations generic_ro_fops = {
28 .llseek = generic_file_llseek,
29 .read_iter = generic_file_read_iter,
30 .mmap = generic_file_readonly_mmap,
31 .splice_read = generic_file_splice_read,
34 EXPORT_SYMBOL(generic_ro_fops);
36 static inline int unsigned_offsets(struct file *file)
38 return file->f_mode & FMODE_UNSIGNED_OFFSET;
42 * vfs_setpos - update the file offset for lseek
43 * @file: file structure in question
44 * @offset: file offset to seek to
45 * @maxsize: maximum file size
47 * This is a low-level filesystem helper for updating the file offset to
48 * the value specified by @offset if the given offset is valid and it is
49 * not equal to the current file offset.
51 * Return the specified offset on success and -EINVAL on invalid offset.
53 loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
55 if (offset < 0 && !unsigned_offsets(file))
60 if (offset != file->f_pos) {
66 EXPORT_SYMBOL(vfs_setpos);
69 * generic_file_llseek_size - generic llseek implementation for regular files
70 * @file: file structure to seek on
71 * @offset: file offset to seek to
72 * @whence: type of seek
73 * @size: max size of this file in file system
74 * @eof: offset used for SEEK_END position
76 * This is a variant of generic_file_llseek that allows passing in a custom
77 * maximum file size and a custom EOF position, for e.g. hashed directories
80 * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
81 * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
82 * read/writes behave like SEEK_SET against seeks.
85 generic_file_llseek_size(struct file *file, loff_t offset, int whence,
86 loff_t maxsize, loff_t eof)
94 * Here we special-case the lseek(fd, 0, SEEK_CUR)
95 * position-querying operation. Avoid rewriting the "same"
96 * f_pos value back to the file because a concurrent read(),
97 * write() or lseek() might have altered it
102 * f_lock protects against read/modify/write race with other
103 * SEEK_CURs. Note that parallel writes and reads behave
106 spin_lock(&file->f_lock);
107 offset = vfs_setpos(file, file->f_pos + offset, maxsize);
108 spin_unlock(&file->f_lock);
112 * In the generic case the entire file is data, so as long as
113 * offset isn't at the end of the file then the offset is data.
120 * There is a virtual hole at the end of the file, so as long as
121 * offset isn't i_size or larger, return i_size.
129 return vfs_setpos(file, offset, maxsize);
131 EXPORT_SYMBOL(generic_file_llseek_size);
134 * generic_file_llseek - generic llseek implementation for regular files
135 * @file: file structure to seek on
136 * @offset: file offset to seek to
137 * @whence: type of seek
139 * This is a generic implemenation of ->llseek useable for all normal local
140 * filesystems. It just updates the file offset to the value specified by
141 * @offset and @whence.
143 loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
145 struct inode *inode = file->f_mapping->host;
147 return generic_file_llseek_size(file, offset, whence,
148 inode->i_sb->s_maxbytes,
151 EXPORT_SYMBOL(generic_file_llseek);
154 * fixed_size_llseek - llseek implementation for fixed-sized devices
155 * @file: file structure to seek on
156 * @offset: file offset to seek to
157 * @whence: type of seek
158 * @size: size of the file
161 loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
164 case SEEK_SET: case SEEK_CUR: case SEEK_END:
165 return generic_file_llseek_size(file, offset, whence,
171 EXPORT_SYMBOL(fixed_size_llseek);
174 * no_seek_end_llseek - llseek implementation for fixed-sized devices
175 * @file: file structure to seek on
176 * @offset: file offset to seek to
177 * @whence: type of seek
180 loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
183 case SEEK_SET: case SEEK_CUR:
184 return generic_file_llseek_size(file, offset, whence,
190 EXPORT_SYMBOL(no_seek_end_llseek);
193 * no_seek_end_llseek_size - llseek implementation for fixed-sized devices
194 * @file: file structure to seek on
195 * @offset: file offset to seek to
196 * @whence: type of seek
197 * @size: maximal offset allowed
200 loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
203 case SEEK_SET: case SEEK_CUR:
204 return generic_file_llseek_size(file, offset, whence,
210 EXPORT_SYMBOL(no_seek_end_llseek_size);
213 * noop_llseek - No Operation Performed llseek implementation
214 * @file: file structure to seek on
215 * @offset: file offset to seek to
216 * @whence: type of seek
218 * This is an implementation of ->llseek useable for the rare special case when
219 * userspace expects the seek to succeed but the (device) file is actually not
220 * able to perform the seek. In this case you use noop_llseek() instead of
221 * falling back to the default implementation of ->llseek.
223 loff_t noop_llseek(struct file *file, loff_t offset, int whence)
227 EXPORT_SYMBOL(noop_llseek);
229 loff_t no_llseek(struct file *file, loff_t offset, int whence)
233 EXPORT_SYMBOL(no_llseek);
235 loff_t default_llseek(struct file *file, loff_t offset, int whence)
237 struct inode *inode = file_inode(file);
240 mutex_lock(&inode->i_mutex);
243 offset += i_size_read(inode);
247 retval = file->f_pos;
250 offset += file->f_pos;
254 * In the generic case the entire file is data, so as
255 * long as offset isn't at the end of the file then the
258 if (offset >= inode->i_size) {
265 * There is a virtual hole at the end of the file, so
266 * as long as offset isn't i_size or larger, return
269 if (offset >= inode->i_size) {
273 offset = inode->i_size;
277 if (offset >= 0 || unsigned_offsets(file)) {
278 if (offset != file->f_pos) {
279 file->f_pos = offset;
285 mutex_unlock(&inode->i_mutex);
288 EXPORT_SYMBOL(default_llseek);
290 loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
292 loff_t (*fn)(struct file *, loff_t, int);
295 if (file->f_mode & FMODE_LSEEK) {
296 if (file->f_op->llseek)
297 fn = file->f_op->llseek;
299 return fn(file, offset, whence);
301 EXPORT_SYMBOL(vfs_llseek);
303 static inline struct fd fdget_pos(int fd)
305 return __to_fd(__fdget_pos(fd));
308 static inline void fdput_pos(struct fd f)
310 if (f.flags & FDPUT_POS_UNLOCK)
311 mutex_unlock(&f.file->f_pos_lock);
315 SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
318 struct fd f = fdget_pos(fd);
323 if (whence <= SEEK_MAX) {
324 loff_t res = vfs_llseek(f.file, offset, whence);
326 if (res != (loff_t)retval)
327 retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
334 COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
336 return sys_lseek(fd, offset, whence);
340 #ifdef __ARCH_WANT_SYS_LLSEEK
341 SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
342 unsigned long, offset_low, loff_t __user *, result,
343 unsigned int, whence)
346 struct fd f = fdget_pos(fd);
353 if (whence > SEEK_MAX)
356 offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
359 retval = (int)offset;
362 if (!copy_to_user(result, &offset, sizeof(offset)))
371 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
376 if (!file->f_op->read_iter)
379 init_sync_kiocb(&kiocb, file);
380 kiocb.ki_pos = *ppos;
383 ret = file->f_op->read_iter(&kiocb, iter);
384 BUG_ON(ret == -EIOCBQUEUED);
386 *ppos = kiocb.ki_pos;
389 EXPORT_SYMBOL(vfs_iter_read);
391 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
396 if (!file->f_op->write_iter)
399 init_sync_kiocb(&kiocb, file);
400 kiocb.ki_pos = *ppos;
403 ret = file->f_op->write_iter(&kiocb, iter);
404 BUG_ON(ret == -EIOCBQUEUED);
406 *ppos = kiocb.ki_pos;
409 EXPORT_SYMBOL(vfs_iter_write);
412 * rw_verify_area doesn't like huge counts. We limit
413 * them to something that fits in "int" so that others
414 * won't have to do range checks all the time.
416 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
420 int retval = -EINVAL;
422 inode = file_inode(file);
423 if (unlikely((ssize_t) count < 0))
426 if (unlikely(pos < 0)) {
427 if (!unsigned_offsets(file))
429 if (count >= -pos) /* both values are in 0..LLONG_MAX */
431 } else if (unlikely((loff_t) (pos + count) < 0)) {
432 if (!unsigned_offsets(file))
436 if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
437 retval = locks_mandatory_area(
438 read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
439 inode, file, pos, count);
443 retval = security_file_permission(file,
444 read_write == READ ? MAY_READ : MAY_WRITE);
447 return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
450 static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
452 struct iovec iov = { .iov_base = buf, .iov_len = len };
454 struct iov_iter iter;
457 init_sync_kiocb(&kiocb, filp);
458 kiocb.ki_pos = *ppos;
459 iov_iter_init(&iter, READ, &iov, 1, len);
461 ret = filp->f_op->read_iter(&kiocb, &iter);
462 BUG_ON(ret == -EIOCBQUEUED);
463 *ppos = kiocb.ki_pos;
467 ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
470 if (file->f_op->read)
471 return file->f_op->read(file, buf, count, pos);
472 else if (file->f_op->read_iter)
473 return new_sync_read(file, buf, count, pos);
477 EXPORT_SYMBOL(__vfs_read);
479 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
483 if (!(file->f_mode & FMODE_READ))
485 if (!(file->f_mode & FMODE_CAN_READ))
487 if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
490 ret = rw_verify_area(READ, file, pos, count);
493 ret = __vfs_read(file, buf, count, pos);
495 fsnotify_access(file);
496 add_rchar(current, ret);
504 EXPORT_SYMBOL(vfs_read);
506 static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
508 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
510 struct iov_iter iter;
513 init_sync_kiocb(&kiocb, filp);
514 kiocb.ki_pos = *ppos;
515 iov_iter_init(&iter, WRITE, &iov, 1, len);
517 ret = filp->f_op->write_iter(&kiocb, &iter);
518 BUG_ON(ret == -EIOCBQUEUED);
520 *ppos = kiocb.ki_pos;
524 ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
527 if (file->f_op->write)
528 return file->f_op->write(file, p, count, pos);
529 else if (file->f_op->write_iter)
530 return new_sync_write(file, p, count, pos);
534 EXPORT_SYMBOL(__vfs_write);
536 ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
539 const char __user *p;
542 if (!(file->f_mode & FMODE_CAN_WRITE))
547 p = (__force const char __user *)buf;
548 if (count > MAX_RW_COUNT)
549 count = MAX_RW_COUNT;
550 ret = __vfs_write(file, p, count, pos);
553 fsnotify_modify(file);
554 add_wchar(current, ret);
560 EXPORT_SYMBOL(__kernel_write);
562 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
566 if (!(file->f_mode & FMODE_WRITE))
568 if (!(file->f_mode & FMODE_CAN_WRITE))
570 if (unlikely(!access_ok(VERIFY_READ, buf, count)))
573 ret = rw_verify_area(WRITE, file, pos, count);
576 file_start_write(file);
577 ret = __vfs_write(file, buf, count, pos);
579 fsnotify_modify(file);
580 add_wchar(current, ret);
583 file_end_write(file);
589 EXPORT_SYMBOL(vfs_write);
591 static inline loff_t file_pos_read(struct file *file)
596 static inline void file_pos_write(struct file *file, loff_t pos)
601 SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
603 struct fd f = fdget_pos(fd);
604 ssize_t ret = -EBADF;
607 loff_t pos = file_pos_read(f.file);
608 ret = vfs_read(f.file, buf, count, &pos);
610 file_pos_write(f.file, pos);
616 SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
619 struct fd f = fdget_pos(fd);
620 ssize_t ret = -EBADF;
623 loff_t pos = file_pos_read(f.file);
624 ret = vfs_write(f.file, buf, count, &pos);
626 file_pos_write(f.file, pos);
633 SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
634 size_t, count, loff_t, pos)
637 ssize_t ret = -EBADF;
645 if (f.file->f_mode & FMODE_PREAD)
646 ret = vfs_read(f.file, buf, count, &pos);
653 SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
654 size_t, count, loff_t, pos)
657 ssize_t ret = -EBADF;
665 if (f.file->f_mode & FMODE_PWRITE)
666 ret = vfs_write(f.file, buf, count, &pos);
674 * Reduce an iovec's length in-place. Return the resulting number of segments
676 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
678 unsigned long seg = 0;
681 while (seg < nr_segs) {
683 if (len + iov->iov_len >= to) {
684 iov->iov_len = to - len;
692 EXPORT_SYMBOL(iov_shorten);
694 static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
695 loff_t *ppos, iter_fn_t fn)
700 init_sync_kiocb(&kiocb, filp);
701 kiocb.ki_pos = *ppos;
703 ret = fn(&kiocb, iter);
704 BUG_ON(ret == -EIOCBQUEUED);
705 *ppos = kiocb.ki_pos;
709 /* Do it by hand, with file-ops */
710 static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
711 loff_t *ppos, io_fn_t fn)
715 while (iov_iter_count(iter)) {
716 struct iovec iovec = iov_iter_iovec(iter);
719 nr = fn(filp, iovec.iov_base, iovec.iov_len, ppos);
727 if (nr != iovec.iov_len)
729 iov_iter_advance(iter, nr);
735 /* A write operation does a read from user space and vice versa */
736 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
738 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
739 unsigned long nr_segs, unsigned long fast_segs,
740 struct iovec *fast_pointer,
741 struct iovec **ret_pointer)
745 struct iovec *iov = fast_pointer;
748 * SuS says "The readv() function *may* fail if the iovcnt argument
749 * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
750 * traditionally returned zero for zero segments, so...
758 * First get the "struct iovec" from user memory and
759 * verify all the pointers
761 if (nr_segs > UIO_MAXIOV) {
765 if (nr_segs > fast_segs) {
766 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
772 if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
778 * According to the Single Unix Specification we should return EINVAL
779 * if an element length is < 0 when cast to ssize_t or if the
780 * total length would overflow the ssize_t return value of the
783 * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
787 for (seg = 0; seg < nr_segs; seg++) {
788 void __user *buf = iov[seg].iov_base;
789 ssize_t len = (ssize_t)iov[seg].iov_len;
791 /* see if we we're about to use an invalid len or if
792 * it's about to overflow ssize_t */
798 && unlikely(!access_ok(vrfy_dir(type), buf, len))) {
802 if (len > MAX_RW_COUNT - ret) {
803 len = MAX_RW_COUNT - ret;
804 iov[seg].iov_len = len;
813 static ssize_t do_readv_writev(int type, struct file *file,
814 const struct iovec __user * uvector,
815 unsigned long nr_segs, loff_t *pos)
818 struct iovec iovstack[UIO_FASTIOV];
819 struct iovec *iov = iovstack;
820 struct iov_iter iter;
825 ret = import_iovec(type, uvector, nr_segs,
826 ARRAY_SIZE(iovstack), &iov, &iter);
830 tot_len = iov_iter_count(&iter);
833 ret = rw_verify_area(type, file, pos, tot_len);
838 fn = file->f_op->read;
839 iter_fn = file->f_op->read_iter;
841 fn = (io_fn_t)file->f_op->write;
842 iter_fn = file->f_op->write_iter;
843 file_start_write(file);
847 ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
849 ret = do_loop_readv_writev(file, &iter, pos, fn);
852 file_end_write(file);
856 if ((ret + (type == READ)) > 0) {
858 fsnotify_access(file);
860 fsnotify_modify(file);
865 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
866 unsigned long vlen, loff_t *pos)
868 if (!(file->f_mode & FMODE_READ))
870 if (!(file->f_mode & FMODE_CAN_READ))
873 return do_readv_writev(READ, file, vec, vlen, pos);
876 EXPORT_SYMBOL(vfs_readv);
878 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
879 unsigned long vlen, loff_t *pos)
881 if (!(file->f_mode & FMODE_WRITE))
883 if (!(file->f_mode & FMODE_CAN_WRITE))
886 return do_readv_writev(WRITE, file, vec, vlen, pos);
889 EXPORT_SYMBOL(vfs_writev);
891 SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
894 struct fd f = fdget_pos(fd);
895 ssize_t ret = -EBADF;
898 loff_t pos = file_pos_read(f.file);
899 ret = vfs_readv(f.file, vec, vlen, &pos);
901 file_pos_write(f.file, pos);
906 add_rchar(current, ret);
911 SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
914 struct fd f = fdget_pos(fd);
915 ssize_t ret = -EBADF;
918 loff_t pos = file_pos_read(f.file);
919 ret = vfs_writev(f.file, vec, vlen, &pos);
921 file_pos_write(f.file, pos);
926 add_wchar(current, ret);
931 static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
933 #define HALF_LONG_BITS (BITS_PER_LONG / 2)
934 return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
937 SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
938 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
940 loff_t pos = pos_from_hilo(pos_h, pos_l);
942 ssize_t ret = -EBADF;
950 if (f.file->f_mode & FMODE_PREAD)
951 ret = vfs_readv(f.file, vec, vlen, &pos);
956 add_rchar(current, ret);
961 SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
962 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
964 loff_t pos = pos_from_hilo(pos_h, pos_l);
966 ssize_t ret = -EBADF;
974 if (f.file->f_mode & FMODE_PWRITE)
975 ret = vfs_writev(f.file, vec, vlen, &pos);
980 add_wchar(current, ret);
987 static ssize_t compat_do_readv_writev(int type, struct file *file,
988 const struct compat_iovec __user *uvector,
989 unsigned long nr_segs, loff_t *pos)
991 compat_ssize_t tot_len;
992 struct iovec iovstack[UIO_FASTIOV];
993 struct iovec *iov = iovstack;
994 struct iov_iter iter;
999 ret = compat_import_iovec(type, uvector, nr_segs,
1000 UIO_FASTIOV, &iov, &iter);
1004 tot_len = iov_iter_count(&iter);
1007 ret = rw_verify_area(type, file, pos, tot_len);
1012 fn = file->f_op->read;
1013 iter_fn = file->f_op->read_iter;
1015 fn = (io_fn_t)file->f_op->write;
1016 iter_fn = file->f_op->write_iter;
1017 file_start_write(file);
1021 ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
1023 ret = do_loop_readv_writev(file, &iter, pos, fn);
1026 file_end_write(file);
1030 if ((ret + (type == READ)) > 0) {
1032 fsnotify_access(file);
1034 fsnotify_modify(file);
1039 static size_t compat_readv(struct file *file,
1040 const struct compat_iovec __user *vec,
1041 unsigned long vlen, loff_t *pos)
1043 ssize_t ret = -EBADF;
1045 if (!(file->f_mode & FMODE_READ))
1049 if (!(file->f_mode & FMODE_CAN_READ))
1052 ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
1056 add_rchar(current, ret);
1061 COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
1062 const struct compat_iovec __user *,vec,
1063 compat_ulong_t, vlen)
1065 struct fd f = fdget_pos(fd);
1071 pos = f.file->f_pos;
1072 ret = compat_readv(f.file, vec, vlen, &pos);
1074 f.file->f_pos = pos;
1079 static long __compat_sys_preadv64(unsigned long fd,
1080 const struct compat_iovec __user *vec,
1081 unsigned long vlen, loff_t pos)
1092 if (f.file->f_mode & FMODE_PREAD)
1093 ret = compat_readv(f.file, vec, vlen, &pos);
1098 #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
1099 COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
1100 const struct compat_iovec __user *,vec,
1101 unsigned long, vlen, loff_t, pos)
1103 return __compat_sys_preadv64(fd, vec, vlen, pos);
1107 COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
1108 const struct compat_iovec __user *,vec,
1109 compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
1111 loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1113 return __compat_sys_preadv64(fd, vec, vlen, pos);
1116 static size_t compat_writev(struct file *file,
1117 const struct compat_iovec __user *vec,
1118 unsigned long vlen, loff_t *pos)
1120 ssize_t ret = -EBADF;
1122 if (!(file->f_mode & FMODE_WRITE))
1126 if (!(file->f_mode & FMODE_CAN_WRITE))
1129 ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
1133 add_wchar(current, ret);
1138 COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
1139 const struct compat_iovec __user *, vec,
1140 compat_ulong_t, vlen)
1142 struct fd f = fdget_pos(fd);
1148 pos = f.file->f_pos;
1149 ret = compat_writev(f.file, vec, vlen, &pos);
1151 f.file->f_pos = pos;
1156 static long __compat_sys_pwritev64(unsigned long fd,
1157 const struct compat_iovec __user *vec,
1158 unsigned long vlen, loff_t pos)
1169 if (f.file->f_mode & FMODE_PWRITE)
1170 ret = compat_writev(f.file, vec, vlen, &pos);
1175 #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
1176 COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
1177 const struct compat_iovec __user *,vec,
1178 unsigned long, vlen, loff_t, pos)
1180 return __compat_sys_pwritev64(fd, vec, vlen, pos);
1184 COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
1185 const struct compat_iovec __user *,vec,
1186 compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
1188 loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1190 return __compat_sys_pwritev64(fd, vec, vlen, pos);
1194 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
1195 size_t count, loff_t max)
1198 struct inode *in_inode, *out_inode;
1205 * Get input file, and verify that it is ok..
1211 if (!(in.file->f_mode & FMODE_READ))
1215 pos = in.file->f_pos;
1218 if (!(in.file->f_mode & FMODE_PREAD))
1221 retval = rw_verify_area(READ, in.file, &pos, count);
1227 * Get output file, and verify that it is ok..
1230 out = fdget(out_fd);
1233 if (!(out.file->f_mode & FMODE_WRITE))
1236 in_inode = file_inode(in.file);
1237 out_inode = file_inode(out.file);
1238 out_pos = out.file->f_pos;
1239 retval = rw_verify_area(WRITE, out.file, &out_pos, count);
1245 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
1247 if (unlikely(pos + count > max)) {
1248 retval = -EOVERFLOW;
1257 * We need to debate whether we can enable this or not. The
1258 * man page documents EAGAIN return for the output at least,
1259 * and the application is arguably buggy if it doesn't expect
1260 * EAGAIN on a non-blocking file descriptor.
1262 if (in.file->f_flags & O_NONBLOCK)
1263 fl = SPLICE_F_NONBLOCK;
1265 file_start_write(out.file);
1266 retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
1267 file_end_write(out.file);
1270 add_rchar(current, retval);
1271 add_wchar(current, retval);
1272 fsnotify_access(in.file);
1273 fsnotify_modify(out.file);
1274 out.file->f_pos = out_pos;
1278 in.file->f_pos = pos;
1284 retval = -EOVERFLOW;
1294 SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
1301 if (unlikely(get_user(off, offset)))
1304 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1305 if (unlikely(put_user(pos, offset)))
1310 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1313 SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
1319 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1321 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1322 if (unlikely(put_user(pos, offset)))
1327 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1330 #ifdef CONFIG_COMPAT
1331 COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
1332 compat_off_t __user *, offset, compat_size_t, count)
1339 if (unlikely(get_user(off, offset)))
1342 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1343 if (unlikely(put_user(pos, offset)))
1348 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1351 COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
1352 compat_loff_t __user *, offset, compat_size_t, count)
1358 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1360 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1361 if (unlikely(put_user(pos, offset)))
1366 return do_sendfile(out_fd, in_fd, NULL, count, 0);