blob: 58e440df1bc687e3dd3eea50fe38f018a6cc192b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/read_write.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070012#include <linux/aio.h>
Robert Love0eeca282005-07-12 17:06:03 -040013#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/security.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050015#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/syscalls.h>
Linus Torvaldse28cc712006-01-04 16:20:40 -080017#include <linux/pagemap.h>
Jens Axboed6b29d72007-06-04 09:59:47 +020018#include <linux/splice.h>
Al Viro561c6732013-02-24 10:52:26 -050019#include <linux/compat.h>
Al Viro06ae43f2013-03-20 13:19:30 -040020#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
22#include <asm/uaccess.h>
23#include <asm/unistd.h>
24
Al Viroc0bd14af2013-05-04 15:00:54 -040025typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
26typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
27 unsigned long, loff_t);
28
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080029const struct file_operations generic_ro_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 .llseek = generic_file_llseek,
Badari Pulavarty543ade12006-09-30 23:28:48 -070031 .read = do_sync_read,
32 .aio_read = generic_file_aio_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 .mmap = generic_file_readonly_mmap,
Jens Axboe534f2aa2007-06-01 14:52:37 +020034 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -070035};
36
37EXPORT_SYMBOL(generic_ro_fops);
38
Al Virocccb5a12010-12-17 07:44:05 -050039static inline int unsigned_offsets(struct file *file)
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -070040{
Al Virocccb5a12010-12-17 07:44:05 -050041 return file->f_mode & FMODE_UNSIGNED_OFFSET;
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -070042}
43
Jie Liu46a1c2c2013-06-25 12:02:13 +080044/**
45 * vfs_setpos - update the file offset for lseek
46 * @file: file structure in question
47 * @offset: file offset to seek to
48 * @maxsize: maximum file size
49 *
50 * This is a low-level filesystem helper for updating the file offset to
51 * the value specified by @offset if the given offset is valid and it is
52 * not equal to the current file offset.
53 *
54 * Return the specified offset on success and -EINVAL on invalid offset.
55 */
56loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
Andi Kleenef3d0fd2011-09-15 16:06:48 -070057{
58 if (offset < 0 && !unsigned_offsets(file))
59 return -EINVAL;
60 if (offset > maxsize)
61 return -EINVAL;
62
63 if (offset != file->f_pos) {
64 file->f_pos = offset;
65 file->f_version = 0;
66 }
67 return offset;
68}
Jie Liu46a1c2c2013-06-25 12:02:13 +080069EXPORT_SYMBOL(vfs_setpos);
Andi Kleenef3d0fd2011-09-15 16:06:48 -070070
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020071/**
Andi Kleen57604952011-09-15 16:06:50 -070072 * generic_file_llseek_size - generic llseek implementation for regular files
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020073 * @file: file structure to seek on
74 * @offset: file offset to seek to
Andrew Morton965c8e52012-12-17 15:59:39 -080075 * @whence: type of seek
Eric Sandeene8b96eb2012-04-30 13:11:29 -050076 * @size: max size of this file in file system
77 * @eof: offset used for SEEK_END position
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020078 *
Andi Kleen57604952011-09-15 16:06:50 -070079 * This is a variant of generic_file_llseek that allows passing in a custom
Eric Sandeene8b96eb2012-04-30 13:11:29 -050080 * maximum file size and a custom EOF position, for e.g. hashed directories
Andi Kleenef3d0fd2011-09-15 16:06:48 -070081 *
82 * Synchronization:
Andi Kleen57604952011-09-15 16:06:50 -070083 * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
Andi Kleenef3d0fd2011-09-15 16:06:48 -070084 * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
85 * read/writes behave like SEEK_SET against seeks.
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020086 */
Andi Kleen9465efc2008-06-27 11:05:24 +020087loff_t
Andrew Morton965c8e52012-12-17 15:59:39 -080088generic_file_llseek_size(struct file *file, loff_t offset, int whence,
Eric Sandeene8b96eb2012-04-30 13:11:29 -050089 loff_t maxsize, loff_t eof)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090{
Andrew Morton965c8e52012-12-17 15:59:39 -080091 switch (whence) {
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020092 case SEEK_END:
Eric Sandeene8b96eb2012-04-30 13:11:29 -050093 offset += eof;
Christoph Hellwig3a8cff42008-08-11 15:37:17 +020094 break;
95 case SEEK_CUR:
Alain Knaff5b6f1eb2008-11-10 17:08:08 -080096 /*
97 * Here we special-case the lseek(fd, 0, SEEK_CUR)
98 * position-querying operation. Avoid rewriting the "same"
99 * f_pos value back to the file because a concurrent read(),
100 * write() or lseek() might have altered it
101 */
102 if (offset == 0)
103 return file->f_pos;
Andi Kleenef3d0fd2011-09-15 16:06:48 -0700104 /*
105 * f_lock protects against read/modify/write race with other
106 * SEEK_CURs. Note that parallel writes and reads behave
107 * like SEEK_SET.
108 */
109 spin_lock(&file->f_lock);
Jie Liu46a1c2c2013-06-25 12:02:13 +0800110 offset = vfs_setpos(file, file->f_pos + offset, maxsize);
Andi Kleenef3d0fd2011-09-15 16:06:48 -0700111 spin_unlock(&file->f_lock);
112 return offset;
Josef Bacik982d8162011-07-18 13:21:35 -0400113 case SEEK_DATA:
114 /*
115 * In the generic case the entire file is data, so as long as
116 * offset isn't at the end of the file then the offset is data.
117 */
Eric Sandeene8b96eb2012-04-30 13:11:29 -0500118 if (offset >= eof)
Josef Bacik982d8162011-07-18 13:21:35 -0400119 return -ENXIO;
120 break;
121 case SEEK_HOLE:
122 /*
123 * There is a virtual hole at the end of the file, so as long as
124 * offset isn't i_size or larger, return i_size.
125 */
Eric Sandeene8b96eb2012-04-30 13:11:29 -0500126 if (offset >= eof)
Josef Bacik982d8162011-07-18 13:21:35 -0400127 return -ENXIO;
Eric Sandeene8b96eb2012-04-30 13:11:29 -0500128 offset = eof;
Josef Bacik982d8162011-07-18 13:21:35 -0400129 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 }
Christoph Hellwig3a8cff42008-08-11 15:37:17 +0200131
Jie Liu46a1c2c2013-06-25 12:02:13 +0800132 return vfs_setpos(file, offset, maxsize);
Andi Kleen57604952011-09-15 16:06:50 -0700133}
134EXPORT_SYMBOL(generic_file_llseek_size);
135
136/**
137 * generic_file_llseek - generic llseek implementation for regular files
138 * @file: file structure to seek on
139 * @offset: file offset to seek to
Andrew Morton965c8e52012-12-17 15:59:39 -0800140 * @whence: type of seek
Andi Kleen57604952011-09-15 16:06:50 -0700141 *
142 * This is a generic implemenation of ->llseek useable for all normal local
143 * filesystems. It just updates the file offset to the value specified by
Ming Lei546ae2d2013-04-29 15:06:07 -0700144 * @offset and @whence.
Andi Kleen57604952011-09-15 16:06:50 -0700145 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800146loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
Andi Kleen57604952011-09-15 16:06:50 -0700147{
148 struct inode *inode = file->f_mapping->host;
149
Andrew Morton965c8e52012-12-17 15:59:39 -0800150 return generic_file_llseek_size(file, offset, whence,
Eric Sandeene8b96eb2012-04-30 13:11:29 -0500151 inode->i_sb->s_maxbytes,
152 i_size_read(inode));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
Andi Kleen9465efc2008-06-27 11:05:24 +0200154EXPORT_SYMBOL(generic_file_llseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
jan Blunckae6afc32010-05-26 14:44:48 -0700156/**
Al Viro1bf9d142013-06-16 20:27:42 +0400157 * fixed_size_llseek - llseek implementation for fixed-sized devices
158 * @file: file structure to seek on
159 * @offset: file offset to seek to
160 * @whence: type of seek
161 * @size: size of the file
162 *
163 */
164loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
165{
166 switch (whence) {
167 case SEEK_SET: case SEEK_CUR: case SEEK_END:
168 return generic_file_llseek_size(file, offset, whence,
169 size, size);
170 default:
171 return -EINVAL;
172 }
173}
174EXPORT_SYMBOL(fixed_size_llseek);
175
176/**
jan Blunckae6afc32010-05-26 14:44:48 -0700177 * noop_llseek - No Operation Performed llseek implementation
178 * @file: file structure to seek on
179 * @offset: file offset to seek to
Andrew Morton965c8e52012-12-17 15:59:39 -0800180 * @whence: type of seek
jan Blunckae6afc32010-05-26 14:44:48 -0700181 *
182 * This is an implementation of ->llseek useable for the rare special case when
183 * userspace expects the seek to succeed but the (device) file is actually not
184 * able to perform the seek. In this case you use noop_llseek() instead of
185 * falling back to the default implementation of ->llseek.
186 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800187loff_t noop_llseek(struct file *file, loff_t offset, int whence)
jan Blunckae6afc32010-05-26 14:44:48 -0700188{
189 return file->f_pos;
190}
191EXPORT_SYMBOL(noop_llseek);
192
Andrew Morton965c8e52012-12-17 15:59:39 -0800193loff_t no_llseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194{
195 return -ESPIPE;
196}
197EXPORT_SYMBOL(no_llseek);
198
Andrew Morton965c8e52012-12-17 15:59:39 -0800199loff_t default_llseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
Al Viro496ad9a2013-01-23 17:07:38 -0500201 struct inode *inode = file_inode(file);
David Sterba16abef02008-04-22 15:09:22 +0200202 loff_t retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Josef Bacik982d8162011-07-18 13:21:35 -0400204 mutex_lock(&inode->i_mutex);
Andrew Morton965c8e52012-12-17 15:59:39 -0800205 switch (whence) {
Chris Snook7b8e8922007-05-08 00:24:13 -0700206 case SEEK_END:
Josef Bacik982d8162011-07-18 13:21:35 -0400207 offset += i_size_read(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 break;
Chris Snook7b8e8922007-05-08 00:24:13 -0700209 case SEEK_CUR:
Alain Knaff5b6f1eb2008-11-10 17:08:08 -0800210 if (offset == 0) {
211 retval = file->f_pos;
212 goto out;
213 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 offset += file->f_pos;
Josef Bacik982d8162011-07-18 13:21:35 -0400215 break;
216 case SEEK_DATA:
217 /*
218 * In the generic case the entire file is data, so as
219 * long as offset isn't at the end of the file then the
220 * offset is data.
221 */
Dan Carpenterbacb2d82011-07-26 17:25:20 +0300222 if (offset >= inode->i_size) {
223 retval = -ENXIO;
224 goto out;
225 }
Josef Bacik982d8162011-07-18 13:21:35 -0400226 break;
227 case SEEK_HOLE:
228 /*
229 * There is a virtual hole at the end of the file, so
230 * as long as offset isn't i_size or larger, return
231 * i_size.
232 */
Dan Carpenterbacb2d82011-07-26 17:25:20 +0300233 if (offset >= inode->i_size) {
234 retval = -ENXIO;
235 goto out;
236 }
Josef Bacik982d8162011-07-18 13:21:35 -0400237 offset = inode->i_size;
238 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 }
240 retval = -EINVAL;
Al Virocccb5a12010-12-17 07:44:05 -0500241 if (offset >= 0 || unsigned_offsets(file)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 if (offset != file->f_pos) {
243 file->f_pos = offset;
244 file->f_version = 0;
245 }
246 retval = offset;
247 }
Alain Knaff5b6f1eb2008-11-10 17:08:08 -0800248out:
Josef Bacik982d8162011-07-18 13:21:35 -0400249 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 return retval;
251}
252EXPORT_SYMBOL(default_llseek);
253
Andrew Morton965c8e52012-12-17 15:59:39 -0800254loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255{
256 loff_t (*fn)(struct file *, loff_t, int);
257
258 fn = no_llseek;
259 if (file->f_mode & FMODE_LSEEK) {
Al Viro72c2d532013-09-22 16:27:52 -0400260 if (file->f_op->llseek)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 fn = file->f_op->llseek;
262 }
Andrew Morton965c8e52012-12-17 15:59:39 -0800263 return fn(file, offset, whence);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264}
265EXPORT_SYMBOL(vfs_llseek);
266
Andrew Morton965c8e52012-12-17 15:59:39 -0800267SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
269 off_t retval;
Al Viro2903ff02012-08-28 12:52:22 -0400270 struct fd f = fdget(fd);
271 if (!f.file)
272 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
274 retval = -EINVAL;
Andrew Morton965c8e52012-12-17 15:59:39 -0800275 if (whence <= SEEK_MAX) {
276 loff_t res = vfs_llseek(f.file, offset, whence);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 retval = res;
278 if (res != (loff_t)retval)
279 retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
280 }
Al Viro2903ff02012-08-28 12:52:22 -0400281 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 return retval;
283}
284
Al Viro561c6732013-02-24 10:52:26 -0500285#ifdef CONFIG_COMPAT
286COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
287{
288 return sys_lseek(fd, offset, whence);
289}
290#endif
291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292#ifdef __ARCH_WANT_SYS_LLSEEK
Heiko Carstens003d7ab2009-01-14 14:14:21 +0100293SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
294 unsigned long, offset_low, loff_t __user *, result,
Andrew Morton965c8e52012-12-17 15:59:39 -0800295 unsigned int, whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296{
297 int retval;
Al Viro2903ff02012-08-28 12:52:22 -0400298 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 loff_t offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
Al Viro2903ff02012-08-28 12:52:22 -0400301 if (!f.file)
302 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304 retval = -EINVAL;
Andrew Morton965c8e52012-12-17 15:59:39 -0800305 if (whence > SEEK_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 goto out_putf;
307
Al Viro2903ff02012-08-28 12:52:22 -0400308 offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
Andrew Morton965c8e52012-12-17 15:59:39 -0800309 whence);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
311 retval = (int)offset;
312 if (offset >= 0) {
313 retval = -EFAULT;
314 if (!copy_to_user(result, &offset, sizeof(offset)))
315 retval = 0;
316 }
317out_putf:
Al Viro2903ff02012-08-28 12:52:22 -0400318 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 return retval;
320}
321#endif
322
Linus Torvaldse28cc712006-01-04 16:20:40 -0800323/*
324 * rw_verify_area doesn't like huge counts. We limit
325 * them to something that fits in "int" so that others
326 * won't have to do range checks all the time.
327 */
Al Viro68d70d02013-06-19 15:26:04 +0400328int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329{
330 struct inode *inode;
331 loff_t pos;
James Morrisc43e2592008-01-12 22:05:48 +1100332 int retval = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
Al Viro496ad9a2013-01-23 17:07:38 -0500334 inode = file_inode(file);
Linus Torvaldse28cc712006-01-04 16:20:40 -0800335 if (unlikely((ssize_t) count < 0))
James Morrisc43e2592008-01-12 22:05:48 +1100336 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 pos = *ppos;
Al Virocccb5a12010-12-17 07:44:05 -0500338 if (unlikely(pos < 0)) {
339 if (!unsigned_offsets(file))
340 return retval;
341 if (count >= -pos) /* both values are in 0..LLONG_MAX */
342 return -EOVERFLOW;
343 } else if (unlikely((loff_t) (pos + count) < 0)) {
344 if (!unsigned_offsets(file))
KAMEZAWA Hiroyuki4a3956c2010-10-01 14:20:22 -0700345 return retval;
346 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
Pavel Emelyanova16877c2007-10-01 14:41:11 -0700348 if (unlikely(inode->i_flock && mandatory_lock(inode))) {
James Morrisc43e2592008-01-12 22:05:48 +1100349 retval = locks_mandatory_area(
Linus Torvaldse28cc712006-01-04 16:20:40 -0800350 read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
351 inode, file, pos, count);
352 if (retval < 0)
353 return retval;
354 }
James Morrisc43e2592008-01-12 22:05:48 +1100355 retval = security_file_permission(file,
356 read_write == READ ? MAY_READ : MAY_WRITE);
357 if (retval)
358 return retval;
Linus Torvaldse28cc712006-01-04 16:20:40 -0800359 return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360}
361
362ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
363{
Badari Pulavarty027445c2006-09-30 23:28:46 -0700364 struct iovec iov = { .iov_base = buf, .iov_len = len };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 struct kiocb kiocb;
366 ssize_t ret;
367
368 init_sync_kiocb(&kiocb, filp);
369 kiocb.ki_pos = *ppos;
David Howells61964eb2010-03-24 17:09:19 +0000370 kiocb.ki_nbytes = len;
Badari Pulavarty027445c2006-09-30 23:28:46 -0700371
Zach Brown41003a72013-05-07 16:18:25 -0700372 ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 if (-EIOCBQUEUED == ret)
374 ret = wait_on_sync_kiocb(&kiocb);
375 *ppos = kiocb.ki_pos;
376 return ret;
377}
378
379EXPORT_SYMBOL(do_sync_read);
380
381ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
382{
383 ssize_t ret;
384
385 if (!(file->f_mode & FMODE_READ))
386 return -EBADF;
Al Viro72c2d532013-09-22 16:27:52 -0400387 if (!file->f_op->read && !file->f_op->aio_read)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 return -EINVAL;
389 if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
390 return -EFAULT;
391
392 ret = rw_verify_area(READ, file, pos, count);
Linus Torvaldse28cc712006-01-04 16:20:40 -0800393 if (ret >= 0) {
394 count = ret;
James Morrisc43e2592008-01-12 22:05:48 +1100395 if (file->f_op->read)
396 ret = file->f_op->read(file, buf, count, pos);
397 else
398 ret = do_sync_read(file, buf, count, pos);
399 if (ret > 0) {
Eric Paris2a12a9d2009-12-17 21:24:21 -0500400 fsnotify_access(file);
James Morrisc43e2592008-01-12 22:05:48 +1100401 add_rchar(current, ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 }
James Morrisc43e2592008-01-12 22:05:48 +1100403 inc_syscr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 }
405
406 return ret;
407}
408
409EXPORT_SYMBOL(vfs_read);
410
411ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
412{
Badari Pulavarty027445c2006-09-30 23:28:46 -0700413 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 struct kiocb kiocb;
415 ssize_t ret;
416
417 init_sync_kiocb(&kiocb, filp);
418 kiocb.ki_pos = *ppos;
David Howells61964eb2010-03-24 17:09:19 +0000419 kiocb.ki_nbytes = len;
Badari Pulavarty027445c2006-09-30 23:28:46 -0700420
Zach Brown41003a72013-05-07 16:18:25 -0700421 ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 if (-EIOCBQUEUED == ret)
423 ret = wait_on_sync_kiocb(&kiocb);
424 *ppos = kiocb.ki_pos;
425 return ret;
426}
427
428EXPORT_SYMBOL(do_sync_write);
429
Al Viro06ae43f2013-03-20 13:19:30 -0400430ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
431{
432 mm_segment_t old_fs;
433 const char __user *p;
434 ssize_t ret;
435
Al Viro72c2d532013-09-22 16:27:52 -0400436 if (!file->f_op->write && !file->f_op->aio_write)
Al Viro3e84f482013-03-27 15:20:30 +0000437 return -EINVAL;
438
Al Viro06ae43f2013-03-20 13:19:30 -0400439 old_fs = get_fs();
440 set_fs(get_ds());
441 p = (__force const char __user *)buf;
442 if (count > MAX_RW_COUNT)
443 count = MAX_RW_COUNT;
444 if (file->f_op->write)
445 ret = file->f_op->write(file, p, count, pos);
446 else
447 ret = do_sync_write(file, p, count, pos);
448 set_fs(old_fs);
449 if (ret > 0) {
450 fsnotify_modify(file);
451 add_wchar(current, ret);
452 }
453 inc_syscw(current);
454 return ret;
455}
456
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
458{
459 ssize_t ret;
460
461 if (!(file->f_mode & FMODE_WRITE))
462 return -EBADF;
Al Viro72c2d532013-09-22 16:27:52 -0400463 if (!file->f_op->write && !file->f_op->aio_write)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 return -EINVAL;
465 if (unlikely(!access_ok(VERIFY_READ, buf, count)))
466 return -EFAULT;
467
468 ret = rw_verify_area(WRITE, file, pos, count);
Linus Torvaldse28cc712006-01-04 16:20:40 -0800469 if (ret >= 0) {
470 count = ret;
Al Viro03d95eb2013-03-20 13:04:20 -0400471 file_start_write(file);
James Morrisc43e2592008-01-12 22:05:48 +1100472 if (file->f_op->write)
473 ret = file->f_op->write(file, buf, count, pos);
474 else
475 ret = do_sync_write(file, buf, count, pos);
476 if (ret > 0) {
Eric Paris2a12a9d2009-12-17 21:24:21 -0500477 fsnotify_modify(file);
James Morrisc43e2592008-01-12 22:05:48 +1100478 add_wchar(current, ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 }
James Morrisc43e2592008-01-12 22:05:48 +1100480 inc_syscw(current);
Al Viro03d95eb2013-03-20 13:04:20 -0400481 file_end_write(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 }
483
484 return ret;
485}
486
487EXPORT_SYMBOL(vfs_write);
488
489static inline loff_t file_pos_read(struct file *file)
490{
491 return file->f_pos;
492}
493
494static inline void file_pos_write(struct file *file, loff_t pos)
495{
496 file->f_pos = pos;
497}
498
Heiko Carstens3cdad422009-01-14 14:14:22 +0100499SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500{
Al Viro2903ff02012-08-28 12:52:22 -0400501 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
Al Viro2903ff02012-08-28 12:52:22 -0400504 if (f.file) {
505 loff_t pos = file_pos_read(f.file);
506 ret = vfs_read(f.file, buf, count, &pos);
Al Viro5faf1532013-06-15 05:49:36 +0400507 if (ret >= 0)
508 file_pos_write(f.file, pos);
Al Viro2903ff02012-08-28 12:52:22 -0400509 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 return ret;
512}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513
Heiko Carstens3cdad422009-01-14 14:14:22 +0100514SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
515 size_t, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516{
Al Viro2903ff02012-08-28 12:52:22 -0400517 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519
Al Viro2903ff02012-08-28 12:52:22 -0400520 if (f.file) {
521 loff_t pos = file_pos_read(f.file);
522 ret = vfs_write(f.file, buf, count, &pos);
Al Viro5faf1532013-06-15 05:49:36 +0400523 if (ret >= 0)
524 file_pos_write(f.file, pos);
Al Viro2903ff02012-08-28 12:52:22 -0400525 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 }
527
528 return ret;
529}
530
Al Viro4a0fd5b2013-01-21 15:16:58 -0500531SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
532 size_t, count, loff_t, pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533{
Al Viro2903ff02012-08-28 12:52:22 -0400534 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
537 if (pos < 0)
538 return -EINVAL;
539
Al Viro2903ff02012-08-28 12:52:22 -0400540 f = fdget(fd);
541 if (f.file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 ret = -ESPIPE;
Al Viro2903ff02012-08-28 12:52:22 -0400543 if (f.file->f_mode & FMODE_PREAD)
544 ret = vfs_read(f.file, buf, count, &pos);
545 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 }
547
548 return ret;
549}
550
Al Viro4a0fd5b2013-01-21 15:16:58 -0500551SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
552 size_t, count, loff_t, pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553{
Al Viro2903ff02012-08-28 12:52:22 -0400554 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556
557 if (pos < 0)
558 return -EINVAL;
559
Al Viro2903ff02012-08-28 12:52:22 -0400560 f = fdget(fd);
561 if (f.file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 ret = -ESPIPE;
Al Viro2903ff02012-08-28 12:52:22 -0400563 if (f.file->f_mode & FMODE_PWRITE)
564 ret = vfs_write(f.file, buf, count, &pos);
565 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 }
567
568 return ret;
569}
570
571/*
572 * Reduce an iovec's length in-place. Return the resulting number of segments
573 */
574unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
575{
576 unsigned long seg = 0;
577 size_t len = 0;
578
579 while (seg < nr_segs) {
580 seg++;
581 if (len + iov->iov_len >= to) {
582 iov->iov_len = to - len;
583 break;
584 }
585 len += iov->iov_len;
586 iov++;
587 }
588 return seg;
589}
Eric Sandeen19295522008-01-28 23:58:27 -0500590EXPORT_SYMBOL(iov_shorten);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
Al Viro72ec3512013-03-20 10:42:10 -0400592static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700593 unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
594{
595 struct kiocb kiocb;
596 ssize_t ret;
597
598 init_sync_kiocb(&kiocb, filp);
599 kiocb.ki_pos = *ppos;
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700600 kiocb.ki_nbytes = len;
601
Zach Brown41003a72013-05-07 16:18:25 -0700602 ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700603 if (ret == -EIOCBQUEUED)
604 ret = wait_on_sync_kiocb(&kiocb);
605 *ppos = kiocb.ki_pos;
606 return ret;
607}
608
609/* Do it by hand, with file-ops */
Al Viro72ec3512013-03-20 10:42:10 -0400610static ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700611 unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
612{
613 struct iovec *vector = iov;
614 ssize_t ret = 0;
615
616 while (nr_segs > 0) {
617 void __user *base;
618 size_t len;
619 ssize_t nr;
620
621 base = vector->iov_base;
622 len = vector->iov_len;
623 vector++;
624 nr_segs--;
625
626 nr = fn(filp, base, len, ppos);
627
628 if (nr < 0) {
629 if (!ret)
630 ret = nr;
631 break;
632 }
633 ret += nr;
634 if (nr != len)
635 break;
636 }
637
638 return ret;
639}
640
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641/* A write operation does a read from user space and vice versa */
642#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
643
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700644ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
645 unsigned long nr_segs, unsigned long fast_segs,
646 struct iovec *fast_pointer,
Christopher Yeohac34ebb2012-05-31 16:26:42 -0700647 struct iovec **ret_pointer)
Linus Torvalds435f49a2010-10-29 10:36:49 -0700648{
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700649 unsigned long seg;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700650 ssize_t ret;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700651 struct iovec *iov = fast_pointer;
652
Linus Torvalds435f49a2010-10-29 10:36:49 -0700653 /*
654 * SuS says "The readv() function *may* fail if the iovcnt argument
655 * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
656 * traditionally returned zero for zero segments, so...
657 */
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700658 if (nr_segs == 0) {
659 ret = 0;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700660 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700661 }
662
Linus Torvalds435f49a2010-10-29 10:36:49 -0700663 /*
664 * First get the "struct iovec" from user memory and
665 * verify all the pointers
666 */
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700667 if (nr_segs > UIO_MAXIOV) {
668 ret = -EINVAL;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700669 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700670 }
671 if (nr_segs > fast_segs) {
Linus Torvalds435f49a2010-10-29 10:36:49 -0700672 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700673 if (iov == NULL) {
674 ret = -ENOMEM;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700675 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700676 }
Linus Torvalds435f49a2010-10-29 10:36:49 -0700677 }
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700678 if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
679 ret = -EFAULT;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700680 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700681 }
682
Linus Torvalds435f49a2010-10-29 10:36:49 -0700683 /*
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700684 * According to the Single Unix Specification we should return EINVAL
685 * if an element length is < 0 when cast to ssize_t or if the
686 * total length would overflow the ssize_t return value of the
687 * system call.
Linus Torvalds435f49a2010-10-29 10:36:49 -0700688 *
689 * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
690 * overflow case.
691 */
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700692 ret = 0;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700693 for (seg = 0; seg < nr_segs; seg++) {
694 void __user *buf = iov[seg].iov_base;
695 ssize_t len = (ssize_t)iov[seg].iov_len;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700696
697 /* see if we we're about to use an invalid len or if
698 * it's about to overflow ssize_t */
Linus Torvalds435f49a2010-10-29 10:36:49 -0700699 if (len < 0) {
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700700 ret = -EINVAL;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700701 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700702 }
Christopher Yeohac34ebb2012-05-31 16:26:42 -0700703 if (type >= 0
Christopher Yeohfcf63402011-10-31 17:06:39 -0700704 && unlikely(!access_ok(vrfy_dir(type), buf, len))) {
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700705 ret = -EFAULT;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700706 goto out;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700707 }
Linus Torvalds435f49a2010-10-29 10:36:49 -0700708 if (len > MAX_RW_COUNT - ret) {
709 len = MAX_RW_COUNT - ret;
710 iov[seg].iov_len = len;
711 }
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700712 ret += len;
Linus Torvalds435f49a2010-10-29 10:36:49 -0700713 }
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700714out:
715 *ret_pointer = iov;
716 return ret;
717}
718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719static ssize_t do_readv_writev(int type, struct file *file,
720 const struct iovec __user * uvector,
721 unsigned long nr_segs, loff_t *pos)
722{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 size_t tot_len;
724 struct iovec iovstack[UIO_FASTIOV];
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700725 struct iovec *iov = iovstack;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 ssize_t ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 io_fn_t fn;
728 iov_fn_t fnv;
729
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700730 ret = rw_copy_check_uvector(type, uvector, nr_segs,
Christopher Yeohac34ebb2012-05-31 16:26:42 -0700731 ARRAY_SIZE(iovstack), iovstack, &iov);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700732 if (ret <= 0)
733 goto out;
734
735 tot_len = ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 ret = rw_verify_area(type, file, pos, tot_len);
Linus Torvaldse28cc712006-01-04 16:20:40 -0800737 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 goto out;
739
740 fnv = NULL;
741 if (type == READ) {
742 fn = file->f_op->read;
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700743 fnv = file->f_op->aio_read;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 } else {
745 fn = (io_fn_t)file->f_op->write;
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700746 fnv = file->f_op->aio_write;
Al Viro03d95eb2013-03-20 13:04:20 -0400747 file_start_write(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 }
749
Badari Pulavartyee0b3e62006-09-30 23:28:47 -0700750 if (fnv)
751 ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
752 pos, fnv);
753 else
754 ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
Al Viro03d95eb2013-03-20 13:04:20 -0400756 if (type != READ)
757 file_end_write(file);
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759out:
760 if (iov != iovstack)
761 kfree(iov);
Robert Love0eeca282005-07-12 17:06:03 -0400762 if ((ret + (type == READ)) > 0) {
763 if (type == READ)
Eric Paris2a12a9d2009-12-17 21:24:21 -0500764 fsnotify_access(file);
Robert Love0eeca282005-07-12 17:06:03 -0400765 else
Eric Paris2a12a9d2009-12-17 21:24:21 -0500766 fsnotify_modify(file);
Robert Love0eeca282005-07-12 17:06:03 -0400767 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769}
770
771ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
772 unsigned long vlen, loff_t *pos)
773{
774 if (!(file->f_mode & FMODE_READ))
775 return -EBADF;
Al Viro72c2d532013-09-22 16:27:52 -0400776 if (!file->f_op->aio_read && !file->f_op->read)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 return -EINVAL;
778
779 return do_readv_writev(READ, file, vec, vlen, pos);
780}
781
782EXPORT_SYMBOL(vfs_readv);
783
784ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
785 unsigned long vlen, loff_t *pos)
786{
787 if (!(file->f_mode & FMODE_WRITE))
788 return -EBADF;
Al Viro72c2d532013-09-22 16:27:52 -0400789 if (!file->f_op->aio_write && !file->f_op->write)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 return -EINVAL;
791
792 return do_readv_writev(WRITE, file, vec, vlen, pos);
793}
794
795EXPORT_SYMBOL(vfs_writev);
796
Heiko Carstens3cdad422009-01-14 14:14:22 +0100797SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
798 unsigned long, vlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799{
Al Viro2903ff02012-08-28 12:52:22 -0400800 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802
Al Viro2903ff02012-08-28 12:52:22 -0400803 if (f.file) {
804 loff_t pos = file_pos_read(f.file);
805 ret = vfs_readv(f.file, vec, vlen, &pos);
Al Viro5faf1532013-06-15 05:49:36 +0400806 if (ret >= 0)
807 file_pos_write(f.file, pos);
Al Viro2903ff02012-08-28 12:52:22 -0400808 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 }
810
811 if (ret > 0)
Alexey Dobriyan4b98d112007-02-10 01:46:45 -0800812 add_rchar(current, ret);
813 inc_syscr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 return ret;
815}
816
Heiko Carstens3cdad422009-01-14 14:14:22 +0100817SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
818 unsigned long, vlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819{
Al Viro2903ff02012-08-28 12:52:22 -0400820 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 ssize_t ret = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822
Al Viro2903ff02012-08-28 12:52:22 -0400823 if (f.file) {
824 loff_t pos = file_pos_read(f.file);
825 ret = vfs_writev(f.file, vec, vlen, &pos);
Al Viro5faf1532013-06-15 05:49:36 +0400826 if (ret >= 0)
827 file_pos_write(f.file, pos);
Al Viro2903ff02012-08-28 12:52:22 -0400828 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 }
830
831 if (ret > 0)
Alexey Dobriyan4b98d112007-02-10 01:46:45 -0800832 add_wchar(current, ret);
833 inc_syscw(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 return ret;
835}
836
Linus Torvalds601cc112009-04-03 08:03:22 -0700837static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700838{
Linus Torvalds601cc112009-04-03 08:03:22 -0700839#define HALF_LONG_BITS (BITS_PER_LONG / 2)
840 return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
841}
842
843SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
844 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
845{
846 loff_t pos = pos_from_hilo(pos_h, pos_l);
Al Viro2903ff02012-08-28 12:52:22 -0400847 struct fd f;
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700848 ssize_t ret = -EBADF;
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700849
850 if (pos < 0)
851 return -EINVAL;
852
Al Viro2903ff02012-08-28 12:52:22 -0400853 f = fdget(fd);
854 if (f.file) {
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700855 ret = -ESPIPE;
Al Viro2903ff02012-08-28 12:52:22 -0400856 if (f.file->f_mode & FMODE_PREAD)
857 ret = vfs_readv(f.file, vec, vlen, &pos);
858 fdput(f);
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700859 }
860
861 if (ret > 0)
862 add_rchar(current, ret);
863 inc_syscr(current);
864 return ret;
865}
866
867SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
Linus Torvalds601cc112009-04-03 08:03:22 -0700868 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700869{
Linus Torvalds601cc112009-04-03 08:03:22 -0700870 loff_t pos = pos_from_hilo(pos_h, pos_l);
Al Viro2903ff02012-08-28 12:52:22 -0400871 struct fd f;
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700872 ssize_t ret = -EBADF;
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700873
874 if (pos < 0)
875 return -EINVAL;
876
Al Viro2903ff02012-08-28 12:52:22 -0400877 f = fdget(fd);
878 if (f.file) {
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700879 ret = -ESPIPE;
Al Viro2903ff02012-08-28 12:52:22 -0400880 if (f.file->f_mode & FMODE_PWRITE)
881 ret = vfs_writev(f.file, vec, vlen, &pos);
882 fdput(f);
Gerd Hoffmannf3554f42009-04-02 16:59:23 -0700883 }
884
885 if (ret > 0)
886 add_wchar(current, ret);
887 inc_syscw(current);
888 return ret;
889}
890
Al Viro72ec3512013-03-20 10:42:10 -0400891#ifdef CONFIG_COMPAT
892
893static ssize_t compat_do_readv_writev(int type, struct file *file,
894 const struct compat_iovec __user *uvector,
895 unsigned long nr_segs, loff_t *pos)
896{
897 compat_ssize_t tot_len;
898 struct iovec iovstack[UIO_FASTIOV];
899 struct iovec *iov = iovstack;
900 ssize_t ret;
901 io_fn_t fn;
902 iov_fn_t fnv;
903
Al Viro72ec3512013-03-20 10:42:10 -0400904 ret = -EFAULT;
905 if (!access_ok(VERIFY_READ, uvector, nr_segs*sizeof(*uvector)))
906 goto out;
907
908 ret = compat_rw_copy_check_uvector(type, uvector, nr_segs,
909 UIO_FASTIOV, iovstack, &iov);
910 if (ret <= 0)
911 goto out;
912
913 tot_len = ret;
914 ret = rw_verify_area(type, file, pos, tot_len);
915 if (ret < 0)
916 goto out;
917
918 fnv = NULL;
919 if (type == READ) {
920 fn = file->f_op->read;
921 fnv = file->f_op->aio_read;
922 } else {
923 fn = (io_fn_t)file->f_op->write;
924 fnv = file->f_op->aio_write;
Al Viro03d95eb2013-03-20 13:04:20 -0400925 file_start_write(file);
Al Viro72ec3512013-03-20 10:42:10 -0400926 }
927
Al Viro03d95eb2013-03-20 13:04:20 -0400928 if (fnv)
Al Viro72ec3512013-03-20 10:42:10 -0400929 ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
930 pos, fnv);
Al Viro03d95eb2013-03-20 13:04:20 -0400931 else
Al Viro72ec3512013-03-20 10:42:10 -0400932 ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
933
Al Viro03d95eb2013-03-20 13:04:20 -0400934 if (type != READ)
935 file_end_write(file);
936
Al Viro72ec3512013-03-20 10:42:10 -0400937out:
938 if (iov != iovstack)
939 kfree(iov);
940 if ((ret + (type == READ)) > 0) {
941 if (type == READ)
942 fsnotify_access(file);
943 else
944 fsnotify_modify(file);
945 }
946 return ret;
947}
948
949static size_t compat_readv(struct file *file,
950 const struct compat_iovec __user *vec,
951 unsigned long vlen, loff_t *pos)
952{
953 ssize_t ret = -EBADF;
954
955 if (!(file->f_mode & FMODE_READ))
956 goto out;
957
958 ret = -EINVAL;
Al Viro72c2d532013-09-22 16:27:52 -0400959 if (!file->f_op->aio_read && !file->f_op->read)
Al Viro72ec3512013-03-20 10:42:10 -0400960 goto out;
961
962 ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
963
964out:
965 if (ret > 0)
966 add_rchar(current, ret);
967 inc_syscr(current);
968 return ret;
969}
970
971COMPAT_SYSCALL_DEFINE3(readv, unsigned long, fd,
972 const struct compat_iovec __user *,vec,
973 unsigned long, vlen)
974{
975 struct fd f = fdget(fd);
976 ssize_t ret;
977 loff_t pos;
978
979 if (!f.file)
980 return -EBADF;
981 pos = f.file->f_pos;
982 ret = compat_readv(f.file, vec, vlen, &pos);
Al Viro5faf1532013-06-15 05:49:36 +0400983 if (ret >= 0)
984 f.file->f_pos = pos;
Al Viro72ec3512013-03-20 10:42:10 -0400985 fdput(f);
986 return ret;
987}
988
989COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
990 const struct compat_iovec __user *,vec,
991 unsigned long, vlen, loff_t, pos)
992{
993 struct fd f;
994 ssize_t ret;
995
996 if (pos < 0)
997 return -EINVAL;
998 f = fdget(fd);
999 if (!f.file)
1000 return -EBADF;
1001 ret = -ESPIPE;
1002 if (f.file->f_mode & FMODE_PREAD)
1003 ret = compat_readv(f.file, vec, vlen, &pos);
1004 fdput(f);
1005 return ret;
1006}
1007
1008COMPAT_SYSCALL_DEFINE5(preadv, unsigned long, fd,
1009 const struct compat_iovec __user *,vec,
1010 unsigned long, vlen, u32, pos_low, u32, pos_high)
1011{
1012 loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1013 return compat_sys_preadv64(fd, vec, vlen, pos);
1014}
1015
1016static size_t compat_writev(struct file *file,
1017 const struct compat_iovec __user *vec,
1018 unsigned long vlen, loff_t *pos)
1019{
1020 ssize_t ret = -EBADF;
1021
1022 if (!(file->f_mode & FMODE_WRITE))
1023 goto out;
1024
1025 ret = -EINVAL;
Al Viro72c2d532013-09-22 16:27:52 -04001026 if (!file->f_op->aio_write && !file->f_op->write)
Al Viro72ec3512013-03-20 10:42:10 -04001027 goto out;
1028
1029 ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
1030
1031out:
1032 if (ret > 0)
1033 add_wchar(current, ret);
1034 inc_syscw(current);
1035 return ret;
1036}
1037
1038COMPAT_SYSCALL_DEFINE3(writev, unsigned long, fd,
1039 const struct compat_iovec __user *, vec,
1040 unsigned long, vlen)
1041{
1042 struct fd f = fdget(fd);
1043 ssize_t ret;
1044 loff_t pos;
1045
1046 if (!f.file)
1047 return -EBADF;
1048 pos = f.file->f_pos;
1049 ret = compat_writev(f.file, vec, vlen, &pos);
Al Viro5faf1532013-06-15 05:49:36 +04001050 if (ret >= 0)
1051 f.file->f_pos = pos;
Al Viro72ec3512013-03-20 10:42:10 -04001052 fdput(f);
1053 return ret;
1054}
1055
1056COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
1057 const struct compat_iovec __user *,vec,
1058 unsigned long, vlen, loff_t, pos)
1059{
1060 struct fd f;
1061 ssize_t ret;
1062
1063 if (pos < 0)
1064 return -EINVAL;
1065 f = fdget(fd);
1066 if (!f.file)
1067 return -EBADF;
1068 ret = -ESPIPE;
1069 if (f.file->f_mode & FMODE_PWRITE)
1070 ret = compat_writev(f.file, vec, vlen, &pos);
1071 fdput(f);
1072 return ret;
1073}
1074
1075COMPAT_SYSCALL_DEFINE5(pwritev, unsigned long, fd,
1076 const struct compat_iovec __user *,vec,
1077 unsigned long, vlen, u32, pos_low, u32, pos_high)
1078{
1079 loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1080 return compat_sys_pwritev64(fd, vec, vlen, pos);
1081}
1082#endif
1083
Al Viro19f4fc32013-02-24 02:17:03 -05001084static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
1085 size_t count, loff_t max)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086{
Al Viro2903ff02012-08-28 12:52:22 -04001087 struct fd in, out;
1088 struct inode *in_inode, *out_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 loff_t pos;
Al Viro7995bd22013-06-20 18:58:36 +04001090 loff_t out_pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 ssize_t retval;
Al Viro2903ff02012-08-28 12:52:22 -04001092 int fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
1094 /*
1095 * Get input file, and verify that it is ok..
1096 */
1097 retval = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001098 in = fdget(in_fd);
1099 if (!in.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 goto out;
Al Viro2903ff02012-08-28 12:52:22 -04001101 if (!(in.file->f_mode & FMODE_READ))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 goto fput_in;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 retval = -ESPIPE;
Al Viro7995bd22013-06-20 18:58:36 +04001104 if (!ppos) {
1105 pos = in.file->f_pos;
1106 } else {
1107 pos = *ppos;
Al Viro2903ff02012-08-28 12:52:22 -04001108 if (!(in.file->f_mode & FMODE_PREAD))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109 goto fput_in;
Al Viro7995bd22013-06-20 18:58:36 +04001110 }
1111 retval = rw_verify_area(READ, in.file, &pos, count);
Linus Torvaldse28cc712006-01-04 16:20:40 -08001112 if (retval < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 goto fput_in;
Linus Torvaldse28cc712006-01-04 16:20:40 -08001114 count = retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 /*
1117 * Get output file, and verify that it is ok..
1118 */
1119 retval = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001120 out = fdget(out_fd);
1121 if (!out.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 goto fput_in;
Al Viro2903ff02012-08-28 12:52:22 -04001123 if (!(out.file->f_mode & FMODE_WRITE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124 goto fput_out;
1125 retval = -EINVAL;
Al Viro496ad9a2013-01-23 17:07:38 -05001126 in_inode = file_inode(in.file);
1127 out_inode = file_inode(out.file);
Al Viro7995bd22013-06-20 18:58:36 +04001128 out_pos = out.file->f_pos;
1129 retval = rw_verify_area(WRITE, out.file, &out_pos, count);
Linus Torvaldse28cc712006-01-04 16:20:40 -08001130 if (retval < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 goto fput_out;
Linus Torvaldse28cc712006-01-04 16:20:40 -08001132 count = retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 if (!max)
1135 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
1136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 if (unlikely(pos + count > max)) {
1138 retval = -EOVERFLOW;
1139 if (pos >= max)
1140 goto fput_out;
1141 count = max - pos;
1142 }
1143
Jens Axboed96e6e72007-06-11 12:18:52 +02001144 fl = 0;
Jens Axboe534f2aa2007-06-01 14:52:37 +02001145#if 0
Jens Axboed96e6e72007-06-11 12:18:52 +02001146 /*
1147 * We need to debate whether we can enable this or not. The
1148 * man page documents EAGAIN return for the output at least,
1149 * and the application is arguably buggy if it doesn't expect
1150 * EAGAIN on a non-blocking file descriptor.
1151 */
Al Viro2903ff02012-08-28 12:52:22 -04001152 if (in.file->f_flags & O_NONBLOCK)
Jens Axboed96e6e72007-06-11 12:18:52 +02001153 fl = SPLICE_F_NONBLOCK;
Jens Axboe534f2aa2007-06-01 14:52:37 +02001154#endif
Al Viro50cd2c52013-05-23 20:10:34 -04001155 file_start_write(out.file);
Al Viro7995bd22013-06-20 18:58:36 +04001156 retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
Al Viro50cd2c52013-05-23 20:10:34 -04001157 file_end_write(out.file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158
1159 if (retval > 0) {
Alexey Dobriyan4b98d112007-02-10 01:46:45 -08001160 add_rchar(current, retval);
1161 add_wchar(current, retval);
Scott Wolchoka68c2f12012-12-20 15:05:52 -08001162 fsnotify_access(in.file);
1163 fsnotify_modify(out.file);
Al Viro7995bd22013-06-20 18:58:36 +04001164 out.file->f_pos = out_pos;
1165 if (ppos)
1166 *ppos = pos;
1167 else
1168 in.file->f_pos = pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170
Alexey Dobriyan4b98d112007-02-10 01:46:45 -08001171 inc_syscr(current);
1172 inc_syscw(current);
Al Viro7995bd22013-06-20 18:58:36 +04001173 if (pos > max)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 retval = -EOVERFLOW;
1175
1176fput_out:
Al Viro2903ff02012-08-28 12:52:22 -04001177 fdput(out);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178fput_in:
Al Viro2903ff02012-08-28 12:52:22 -04001179 fdput(in);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180out:
1181 return retval;
1182}
1183
Heiko Carstens002c8972009-01-14 14:14:18 +01001184SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185{
1186 loff_t pos;
1187 off_t off;
1188 ssize_t ret;
1189
1190 if (offset) {
1191 if (unlikely(get_user(off, offset)))
1192 return -EFAULT;
1193 pos = off;
1194 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1195 if (unlikely(put_user(pos, offset)))
1196 return -EFAULT;
1197 return ret;
1198 }
1199
1200 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1201}
1202
Heiko Carstens002c8972009-01-14 14:14:18 +01001203SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204{
1205 loff_t pos;
1206 ssize_t ret;
1207
1208 if (offset) {
1209 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1210 return -EFAULT;
1211 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1212 if (unlikely(put_user(pos, offset)))
1213 return -EFAULT;
1214 return ret;
1215 }
1216
1217 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1218}
Al Viro19f4fc32013-02-24 02:17:03 -05001219
1220#ifdef CONFIG_COMPAT
1221COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
1222 compat_off_t __user *, offset, compat_size_t, count)
1223{
1224 loff_t pos;
1225 off_t off;
1226 ssize_t ret;
1227
1228 if (offset) {
1229 if (unlikely(get_user(off, offset)))
1230 return -EFAULT;
1231 pos = off;
1232 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1233 if (unlikely(put_user(pos, offset)))
1234 return -EFAULT;
1235 return ret;
1236 }
1237
1238 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1239}
1240
1241COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
1242 compat_loff_t __user *, offset, compat_size_t, count)
1243{
1244 loff_t pos;
1245 ssize_t ret;
1246
1247 if (offset) {
1248 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1249 return -EFAULT;
1250 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1251 if (unlikely(put_user(pos, offset)))
1252 return -EFAULT;
1253 return ret;
1254 }
1255
1256 return do_sendfile(out_fd, in_fd, NULL, count, 0);
1257}
1258#endif