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tty: implement read_iter
Now that the ldisc read() function takes kernel pointers, it's fairly
straightforward to make the tty file operations use .read_iter() instead
of .read().
That automatically gives us vread() and friends, and also makes it
possible to do .splice_read() on ttys again.
Fixes: 36e2c7421f
("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
3b830a9c34
commit
dd78b0c483
1 changed files with 18 additions and 18 deletions
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@ -142,7 +142,7 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */
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/* Mutex to protect creating and releasing a tty */
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/* Mutex to protect creating and releasing a tty */
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DEFINE_MUTEX(tty_mutex);
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DEFINE_MUTEX(tty_mutex);
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static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
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static ssize_t tty_read(struct kiocb *, struct iov_iter *);
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static ssize_t tty_write(struct kiocb *, struct iov_iter *);
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static ssize_t tty_write(struct kiocb *, struct iov_iter *);
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ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
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ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
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static __poll_t tty_poll(struct file *, poll_table *);
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static __poll_t tty_poll(struct file *, poll_table *);
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@ -476,8 +476,9 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file)
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static const struct file_operations tty_fops = {
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static const struct file_operations tty_fops = {
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.llseek = no_llseek,
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.llseek = no_llseek,
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.read = tty_read,
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.read_iter = tty_read,
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.write_iter = tty_write,
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.write_iter = tty_write,
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.splice_read = generic_file_splice_read,
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.splice_write = iter_file_splice_write,
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.splice_write = iter_file_splice_write,
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.poll = tty_poll,
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.poll = tty_poll,
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.unlocked_ioctl = tty_ioctl,
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.unlocked_ioctl = tty_ioctl,
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@ -490,8 +491,9 @@ static const struct file_operations tty_fops = {
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static const struct file_operations console_fops = {
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static const struct file_operations console_fops = {
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.llseek = no_llseek,
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.llseek = no_llseek,
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.read = tty_read,
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.read_iter = tty_read,
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.write_iter = redirected_tty_write,
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.write_iter = redirected_tty_write,
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.splice_read = generic_file_splice_read,
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.splice_write = iter_file_splice_write,
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.splice_write = iter_file_splice_write,
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.poll = tty_poll,
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.poll = tty_poll,
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.unlocked_ioctl = tty_ioctl,
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.unlocked_ioctl = tty_ioctl,
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@ -844,16 +846,17 @@ static void tty_update_time(struct timespec64 *time)
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* data or clears the cookie. The cookie may be something that the
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* data or clears the cookie. The cookie may be something that the
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* ldisc maintains state for and needs to free.
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* ldisc maintains state for and needs to free.
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*/
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*/
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static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct file *file,
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static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
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char __user *buf, size_t count)
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struct file *file, struct iov_iter *to)
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{
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{
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int retval = 0;
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int retval = 0;
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void *cookie = NULL;
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void *cookie = NULL;
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unsigned long offset = 0;
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unsigned long offset = 0;
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char kernel_buf[64];
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char kernel_buf[64];
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size_t count = iov_iter_count(to);
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do {
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do {
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int size, uncopied;
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int size, copied;
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size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
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size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
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size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
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size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
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@ -869,10 +872,9 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct
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return size;
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return size;
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}
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}
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uncopied = copy_to_user(buf+offset, kernel_buf, size);
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copied = copy_to_iter(kernel_buf, size, to);
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size -= uncopied;
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offset += copied;
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offset += size;
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count -= copied;
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count -= size;
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/*
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/*
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* If the user copy failed, we still need to do another ->read()
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* If the user copy failed, we still need to do another ->read()
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@ -880,7 +882,7 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct
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*
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*
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* But make sure size is zeroed.
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* But make sure size is zeroed.
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*/
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*/
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if (unlikely(uncopied)) {
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if (unlikely(copied != size)) {
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count = 0;
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count = 0;
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retval = -EFAULT;
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retval = -EFAULT;
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}
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}
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@ -907,10 +909,10 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct
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* read calls may be outstanding in parallel.
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* read calls may be outstanding in parallel.
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*/
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*/
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static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
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static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
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loff_t *ppos)
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{
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{
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int i;
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int i;
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struct file *file = iocb->ki_filp;
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struct inode *inode = file_inode(file);
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struct inode *inode = file_inode(file);
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struct tty_struct *tty = file_tty(file);
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struct tty_struct *tty = file_tty(file);
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struct tty_ldisc *ld;
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struct tty_ldisc *ld;
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@ -923,11 +925,9 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
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/* We want to wait for the line discipline to sort out in this
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/* We want to wait for the line discipline to sort out in this
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situation */
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situation */
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ld = tty_ldisc_ref_wait(tty);
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ld = tty_ldisc_ref_wait(tty);
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if (!ld)
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return hung_up_tty_read(file, buf, count, ppos);
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i = -EIO;
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i = -EIO;
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if (ld->ops->read)
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if (ld && ld->ops->read)
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i = iterate_tty_read(ld, tty, file, buf, count);
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i = iterate_tty_read(ld, tty, file, to);
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tty_ldisc_deref(ld);
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tty_ldisc_deref(ld);
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if (i > 0)
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if (i > 0)
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@ -2927,7 +2927,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
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static int this_tty(const void *t, struct file *file, unsigned fd)
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static int this_tty(const void *t, struct file *file, unsigned fd)
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{
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{
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if (likely(file->f_op->read != tty_read))
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if (likely(file->f_op->read_iter != tty_read))
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return 0;
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return 0;
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return file_tty(file) != t ? 0 : fd + 1;
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return file_tty(file) != t ? 0 : fd + 1;
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}
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}
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