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/smp_lock.h>
13 #include <linux/dnotify.h>
14 #include <linux/security.h>
15 #include <linux/module.h>
17 #include <asm/uaccess.h>
18 #include <asm/unistd.h>
20 struct file_operations generic_ro_fops = {
21 .llseek = generic_file_llseek,
22 .read = generic_file_read,
23 .mmap = generic_file_readonly_mmap,
24 .sendfile = generic_file_sendfile,
27 EXPORT_SYMBOL(generic_ro_fops);
29 loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
32 struct inode *inode = file->f_mapping->host;
37 offset += inode->i_size;
40 offset += file->f_pos;
43 if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
44 if (offset != file->f_pos) {
54 EXPORT_SYMBOL(generic_file_llseek);
56 loff_t remote_llseek(struct file *file, loff_t offset, int origin)
63 offset += i_size_read(file->f_dentry->d_inode);
66 offset += file->f_pos;
69 if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
70 if (offset != file->f_pos) {
79 EXPORT_SYMBOL(remote_llseek);
81 loff_t no_llseek(struct file *file, loff_t offset, int origin)
85 EXPORT_SYMBOL(no_llseek);
87 loff_t default_llseek(struct file *file, loff_t offset, int origin)
94 offset += i_size_read(file->f_dentry->d_inode);
97 offset += file->f_pos;
101 if (offset != file->f_pos) {
102 file->f_pos = offset;
110 EXPORT_SYMBOL(default_llseek);
112 loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
114 loff_t (*fn)(struct file *, loff_t, int);
117 if (file->f_op && file->f_op->llseek)
118 fn = file->f_op->llseek;
119 return fn(file, offset, origin);
121 EXPORT_SYMBOL(vfs_llseek);
123 asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
130 file = fget_light(fd, &fput_needed);
136 loff_t res = vfs_llseek(file, offset, origin);
138 if (res != (loff_t)retval)
139 retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
141 fput_light(file, fput_needed);
146 #ifdef __ARCH_WANT_SYS_LLSEEK
147 asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
148 unsigned long offset_low, loff_t __user * result,
157 file = fget_light(fd, &fput_needed);
165 offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
168 retval = (int)offset;
171 if (!copy_to_user(result, &offset, sizeof(offset)))
175 fput_light(file, fput_needed);
181 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
186 init_sync_kiocb(&kiocb, filp);
187 kiocb.ki_pos = *ppos;
188 ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos);
189 if (-EIOCBQUEUED == ret)
190 ret = wait_on_sync_kiocb(&kiocb);
191 *ppos = kiocb.ki_pos;
195 EXPORT_SYMBOL(do_sync_read);
197 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
199 struct inode *inode = file->f_dentry->d_inode;
202 if (!(file->f_mode & FMODE_READ))
204 if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
207 ret = locks_verify_area(FLOCK_VERIFY_READ, inode, file, *pos, count);
209 ret = security_file_permission (file, MAY_READ);
211 if (file->f_op->read)
212 ret = file->f_op->read(file, buf, count, pos);
214 ret = do_sync_read(file, buf, count, pos);
216 dnotify_parent(file->f_dentry, DN_ACCESS);
223 EXPORT_SYMBOL(vfs_read);
225 ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
230 init_sync_kiocb(&kiocb, filp);
231 kiocb.ki_pos = *ppos;
232 ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos);
233 if (-EIOCBQUEUED == ret)
234 ret = wait_on_sync_kiocb(&kiocb);
235 *ppos = kiocb.ki_pos;
239 EXPORT_SYMBOL(do_sync_write);
241 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
243 struct inode *inode = file->f_dentry->d_inode;
246 if (!(file->f_mode & FMODE_WRITE))
248 if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
251 ret = locks_verify_area(FLOCK_VERIFY_WRITE, inode, file, *pos, count);
253 ret = security_file_permission (file, MAY_WRITE);
255 if (file->f_op->write)
256 ret = file->f_op->write(file, buf, count, pos);
258 ret = do_sync_write(file, buf, count, pos);
260 dnotify_parent(file->f_dentry, DN_MODIFY);
267 EXPORT_SYMBOL(vfs_write);
269 asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
272 ssize_t ret = -EBADF;
275 file = fget_light(fd, &fput_needed);
277 ret = vfs_read(file, buf, count, &file->f_pos);
278 fput_light(file, fput_needed);
284 asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
287 ssize_t ret = -EBADF;
290 file = fget_light(fd, &fput_needed);
292 ret = vfs_write(file, buf, count, &file->f_pos);
293 fput_light(file, fput_needed);
299 asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
300 size_t count, loff_t pos)
303 ssize_t ret = -EBADF;
309 file = fget_light(fd, &fput_needed);
311 ret = vfs_read(file, buf, count, &pos);
312 fput_light(file, fput_needed);
318 asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
319 size_t count, loff_t pos)
322 ssize_t ret = -EBADF;
328 file = fget_light(fd, &fput_needed);
330 ret = vfs_write(file, buf, count, &pos);
331 fput_light(file, fput_needed);
338 * Reduce an iovec's length in-place. Return the resulting number of segments
340 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
342 unsigned long seg = 0;
345 while (seg < nr_segs) {
347 if (len + iov->iov_len >= to) {
348 iov->iov_len = to - len;
357 EXPORT_SYMBOL(iov_shorten);
359 static ssize_t do_readv_writev(int type, struct file *file,
360 const struct iovec __user * uvector,
361 unsigned long nr_segs, loff_t *pos)
363 typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
364 typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);
367 struct iovec iovstack[UIO_FASTIOV];
368 struct iovec *iov=iovstack, *vector;
376 * SuS says "The readv() function *may* fail if the iovcnt argument
377 * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
378 * traditionally returned zero for zero segments, so...
385 * First get the "struct iovec" from user memory and
386 * verify all the pointers
389 if ((nr_segs > UIO_MAXIOV) || (nr_segs <= 0))
393 if (nr_segs > UIO_FASTIOV) {
395 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
400 if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector)))
404 * Single unix specification:
405 * We should -EINVAL if an element length is not >= 0 and fitting an
406 * ssize_t. The total length is fitting an ssize_t
408 * Be careful here because iov_len is a size_t not an ssize_t
412 for (seg = 0; seg < nr_segs; seg++) {
413 ssize_t len = (ssize_t)iov[seg].iov_len;
415 if (len < 0) /* size_t not fitting an ssize_t .. */
418 if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
426 inode = file->f_dentry->d_inode;
427 /* VERIFY_WRITE actually means a read, as we write to user space */
428 ret = locks_verify_area((type == READ
429 ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE),
430 inode, file, *pos, tot_len);
436 fn = file->f_op->read;
437 fnv = file->f_op->readv;
439 fn = (io_fn_t)file->f_op->write;
440 fnv = file->f_op->writev;
443 ret = fnv(file, iov, nr_segs, pos);
447 /* Do it by hand, with file-ops */
450 while (nr_segs > 0) {
455 base = vector->iov_base;
456 len = vector->iov_len;
460 nr = fn(file, base, len, pos);
473 if ((ret + (type == READ)) > 0)
474 dnotify_parent(file->f_dentry,
475 (type == READ) ? DN_ACCESS : DN_MODIFY);
479 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
480 unsigned long vlen, loff_t *pos)
482 if (!(file->f_mode & FMODE_READ))
484 if (!file->f_op || (!file->f_op->readv && !file->f_op->read))
487 return do_readv_writev(READ, file, vec, vlen, pos);
490 EXPORT_SYMBOL(vfs_readv);
492 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
493 unsigned long vlen, loff_t *pos)
495 if (!(file->f_mode & FMODE_WRITE))
497 if (!file->f_op || (!file->f_op->writev && !file->f_op->write))
500 return do_readv_writev(WRITE, file, vec, vlen, pos);
503 EXPORT_SYMBOL(vfs_writev);
506 sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
509 ssize_t ret = -EBADF;
512 file = fget_light(fd, &fput_needed);
514 ret = vfs_readv(file, vec, vlen, &file->f_pos);
515 fput_light(file, fput_needed);
522 sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
525 ssize_t ret = -EBADF;
528 file = fget_light(fd, &fput_needed);
530 ret = vfs_writev(file, vec, vlen, &file->f_pos);
531 fput_light(file, fput_needed);
537 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
538 size_t count, loff_t max)
540 struct file * in_file, * out_file;
541 struct inode * in_inode, * out_inode;
544 int fput_needed_in, fput_needed_out;
547 * Get input file, and verify that it is ok..
550 in_file = fget_light(in_fd, &fput_needed_in);
553 if (!(in_file->f_mode & FMODE_READ))
556 in_inode = in_file->f_dentry->d_inode;
559 if (!in_file->f_op || !in_file->f_op->sendfile)
562 ppos = &in_file->f_pos;
563 retval = locks_verify_area(FLOCK_VERIFY_READ, in_inode, in_file, *ppos, count);
567 retval = security_file_permission (in_file, MAY_READ);
572 * Get output file, and verify that it is ok..
575 out_file = fget_light(out_fd, &fput_needed_out);
578 if (!(out_file->f_mode & FMODE_WRITE))
581 if (!out_file->f_op || !out_file->f_op->sendpage)
583 out_inode = out_file->f_dentry->d_inode;
584 retval = locks_verify_area(FLOCK_VERIFY_WRITE, out_inode, out_file, out_file->f_pos, count);
588 retval = security_file_permission (out_file, MAY_WRITE);
593 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
597 if (unlikely(pos < 0))
599 if (unlikely(pos + count > max)) {
606 retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
612 fput_light(out_file, fput_needed_out);
614 fput_light(in_file, fput_needed_in);
619 asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
626 if (unlikely(get_user(off, offset)))
629 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
630 if (unlikely(put_user(pos, offset)))
635 return do_sendfile(out_fd, in_fd, NULL, count, 0);
638 asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
644 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
646 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
647 if (unlikely(put_user(pos, offset)))
652 return do_sendfile(out_fd, in_fd, NULL, count, 0);