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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-19 22:41:16 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-21 03:48:47 +0300 |
commit | 9bb48c82aced07698a2d08ee0f1475a6c4f6b266 (patch) | |
tree | 32628e37f8e7fdc03eb2c65a850ab860cf892d5d /drivers/tty/tty_io.c | |
parent | 2c85ebc57b3e1817b6ce1a6b703928e113a90442 (diff) | |
download | linux-9bb48c82aced07698a2d08ee0f1475a6c4f6b266.tar.xz |
tty: implement write_iter
This makes the tty layer use the .write_iter() function instead of the
traditional .write() functionality.
That allows writev(), but more importantly also makes it possible to
enable .splice_write() for ttys, reinstating the "splice to tty"
functionality that was lost in commit 36e2c7421f02 ("fs: don't allow
splice read/write without explicit ops").
Fixes: 36e2c7421f02 ("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>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r-- | drivers/tty/tty_io.c | 48 |
1 files changed, 26 insertions, 22 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 56ade99ef99f..338bc4ef5549 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -143,9 +143,8 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ DEFINE_MUTEX(tty_mutex); static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); -static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); -ssize_t redirected_tty_write(struct file *, const char __user *, - size_t, loff_t *); +static ssize_t tty_write(struct kiocb *, struct iov_iter *); +ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *); static __poll_t tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); @@ -478,7 +477,8 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file) static const struct file_operations tty_fops = { .llseek = no_llseek, .read = tty_read, - .write = tty_write, + .write_iter = tty_write, + .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, @@ -491,7 +491,8 @@ static const struct file_operations tty_fops = { static const struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, - .write = redirected_tty_write, + .write_iter = redirected_tty_write, + .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, @@ -607,9 +608,9 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) /* This breaks for file handles being sent over AF_UNIX sockets ? */ list_for_each_entry(priv, &tty->tty_files, list) { filp = priv->file; - if (filp->f_op->write == redirected_tty_write) + if (filp->f_op->write_iter == redirected_tty_write) cons_filp = filp; - if (filp->f_op->write != tty_write) + if (filp->f_op->write_iter != tty_write) continue; closecount++; __tty_fasync(-1, filp, 0); /* can't block */ @@ -902,9 +903,9 @@ static inline ssize_t do_tty_write( ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), struct tty_struct *tty, struct file *file, - const char __user *buf, - size_t count) + struct iov_iter *from) { + size_t count = iov_iter_count(from); ssize_t ret, written = 0; unsigned int chunk; @@ -956,14 +957,20 @@ static inline ssize_t do_tty_write( size_t size = count; if (size > chunk) size = chunk; + ret = -EFAULT; - if (copy_from_user(tty->write_buf, buf, size)) + if (copy_from_iter(tty->write_buf, size, from) != size) break; + ret = write(tty, file, tty->write_buf, size); if (ret <= 0) break; + + /* FIXME! Have Al check this! */ + if (ret != size) + iov_iter_revert(from, size-ret); + written += ret; - buf += ret; count -= ret; if (!count) break; @@ -1023,9 +1030,9 @@ void tty_write_message(struct tty_struct *tty, char *msg) * write method will not be invoked in parallel for each device. */ -static ssize_t tty_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from) { + struct file *file = iocb->ki_filp; struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; ssize_t ret; @@ -1038,18 +1045,15 @@ static ssize_t tty_write(struct file *file, const char __user *buf, if (tty->ops->write_room == NULL) tty_err(tty, "missing write_room method\n"); ld = tty_ldisc_ref_wait(tty); - if (!ld) - return hung_up_tty_write(file, buf, count, ppos); - if (!ld->ops->write) + if (!ld || !ld->ops->write) ret = -EIO; else - ret = do_tty_write(ld->ops->write, tty, file, buf, count); + ret = do_tty_write(ld->ops->write, tty, file, from); tty_ldisc_deref(ld); return ret; } -ssize_t redirected_tty_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter) { struct file *p = NULL; @@ -1060,11 +1064,11 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, if (p) { ssize_t res; - res = vfs_write(p, buf, count, &p->f_pos); + res = vfs_iocb_iter_write(p, iocb, iter); fput(p); return res; } - return tty_write(file, buf, count, ppos); + return tty_write(iocb, iter); } /** @@ -2293,7 +2297,7 @@ static int tioccons(struct file *file) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (file->f_op->write == redirected_tty_write) { + if (file->f_op->write_iter == redirected_tty_write) { struct file *f; spin_lock(&redirect_lock); f = redirect; |