diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/tty/tty_io.c | 215 |
1 files changed, 171 insertions, 44 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 816e709afa56..74733ec8f565 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -142,7 +142,7 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ /* Mutex to protect creating and releasing a tty */ DEFINE_MUTEX(tty_mutex); -static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); +static ssize_t tty_read(struct kiocb *, struct iov_iter *); static ssize_t tty_write(struct kiocb *, struct iov_iter *); static __poll_t tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); @@ -429,8 +429,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) EXPORT_SYMBOL_GPL(tty_find_polling_driver); #endif -static ssize_t hung_up_tty_read(struct file *file, char __user *buf, - size_t count, loff_t *ppos) +static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to) { return 0; } @@ -473,8 +472,9 @@ 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, + .read_iter = tty_read, .write_iter = tty_write, + .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, @@ -487,8 +487,9 @@ static const struct file_operations tty_fops = { static const struct file_operations console_fops = { .llseek = no_llseek, - .read = tty_read, + .read_iter = tty_read, .write_iter = redirected_tty_write, + .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, @@ -500,7 +501,7 @@ static const struct file_operations console_fops = { static const struct file_operations hung_up_tty_fops = { .llseek = no_llseek, - .read = hung_up_tty_read, + .read_iter = hung_up_tty_read, .write_iter = hung_up_tty_write, .poll = hung_up_tty_poll, .unlocked_ioctl = hung_up_tty_ioctl, @@ -539,6 +540,29 @@ void tty_wakeup(struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_wakeup); /** + * tty_release_redirect - Release a redirect on a pty if present + * @tty: tty device + * + * This is available to the pty code so if the master closes, if the + * slave is a redirect it can release the redirect. It returns the + * filp for the redirect, which must be fput when the operations on + * the tty are completed. + */ +struct file *tty_release_redirect(struct tty_struct *tty) +{ + struct file *f = NULL; + + spin_lock(&redirect_lock); + if (redirect && file_tty(redirect) == tty) { + f = redirect; + redirect = NULL; + } + spin_unlock(&redirect_lock); + + return f; +} + +/** * __tty_hangup - actual handler for hangup events * @tty: tty device * @exit_session: if non-zero, signal all foreground group processes @@ -564,7 +588,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup); static void __tty_hangup(struct tty_struct *tty, int exit_session) { struct file *cons_filp = NULL; - struct file *filp, *f = NULL; + struct file *filp, *f; struct tty_file_private *priv; int closecount = 0, n; int refs; @@ -572,13 +596,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) if (!tty) return; - - spin_lock(&redirect_lock); - if (redirect && file_tty(redirect) == tty) { - f = redirect; - redirect = NULL; - } - spin_unlock(&redirect_lock); + f = tty_release_redirect(tty); tty_lock(tty); @@ -829,6 +847,72 @@ static void tty_update_time(struct timespec64 *time) time->tv_sec = sec; } +/* + * Iterate on the ldisc ->read() function until we've gotten all + * the data the ldisc has for us. + * + * The "cookie" is something that the ldisc read function can fill + * in to let us know that there is more data to be had. + * + * We promise to continue to call the ldisc until it stops returning + * data or clears the cookie. The cookie may be something that the + * ldisc maintains state for and needs to free. + */ +static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, + struct file *file, struct iov_iter *to) +{ + int retval = 0; + void *cookie = NULL; + unsigned long offset = 0; + char kernel_buf[64]; + size_t count = iov_iter_count(to); + + do { + int size, copied; + + size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count; + size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset); + if (!size) + break; + + if (size < 0) { + /* Did we have an earlier error (ie -EFAULT)? */ + if (retval) + break; + retval = size; + + /* + * -EOVERFLOW means we didn't have enough space + * for a whole packet, and we shouldn't return + * a partial result. + */ + if (retval == -EOVERFLOW) + offset = 0; + break; + } + + copied = copy_to_iter(kernel_buf, size, to); + offset += copied; + count -= copied; + + /* + * If the user copy failed, we still need to do another ->read() + * call if we had a cookie to let the ldisc clear up. + * + * But make sure size is zeroed. + */ + if (unlikely(copied != size)) { + count = 0; + retval = -EFAULT; + } + } while (cookie); + + /* We always clear tty buffer in case they contained passwords */ + memzero_explicit(kernel_buf, sizeof(kernel_buf)); + return offset ? offset : retval; +} + + /** * tty_read - read method for tty device files * @file: pointer to tty file @@ -844,10 +928,10 @@ static void tty_update_time(struct timespec64 *time) * read calls may be outstanding in parallel. */ -static ssize_t tty_read(struct file *file, char __user *buf, size_t count, - loff_t *ppos) +static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to) { int i; + struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; @@ -861,11 +945,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, situation */ ld = tty_ldisc_ref_wait(tty); if (!ld) - return hung_up_tty_read(file, buf, count, ppos); + return hung_up_tty_read(iocb, to); + i = -EIO; if (ld->ops->read) - i = ld->ops->read(tty, file, buf, count); - else - i = -EIO; + i = iterate_tty_read(ld, tty, file, to); tty_ldisc_deref(ld); if (i > 0) @@ -962,11 +1045,14 @@ static inline ssize_t do_tty_write( if (ret <= 0) break; + written += ret; + if (ret > size) + break; + /* FIXME! Have Al check this! */ if (ret != size) iov_iter_revert(from, size-ret); - written += ret; count -= ret; if (!count) break; @@ -1886,22 +1972,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, return driver; } -/** - * tty_kopen - open a tty device for kernel - * @device: dev_t of device to open - * - * Opens tty exclusively for kernel. Performs the driver lookup, - * makes sure it's not already opened and performs the first-time - * tty initialization. - * - * Returns the locked initialized &tty_struct - * - * Claims the global tty_mutex to serialize: - * - concurrent first-time tty initialization - * - concurrent tty driver removal w/ lookup - * - concurrent tty removal from driver table - */ -struct tty_struct *tty_kopen(dev_t device) +static struct tty_struct *tty_kopen(dev_t device, int shared) { struct tty_struct *tty; struct tty_driver *driver; @@ -1916,7 +1987,7 @@ struct tty_struct *tty_kopen(dev_t device) /* check whether we're reopening an existing tty */ tty = tty_driver_lookup_tty(driver, NULL, index); - if (IS_ERR(tty)) + if (IS_ERR(tty) || shared) goto out; if (tty) { @@ -1934,7 +2005,42 @@ out: tty_driver_kref_put(driver); return tty; } -EXPORT_SYMBOL_GPL(tty_kopen); + +/** + * tty_kopen_exclusive - open a tty device for kernel + * @device: dev_t of device to open + * + * Opens tty exclusively for kernel. Performs the driver lookup, + * makes sure it's not already opened and performs the first-time + * tty initialization. + * + * Returns the locked initialized &tty_struct + * + * Claims the global tty_mutex to serialize: + * - concurrent first-time tty initialization + * - concurrent tty driver removal w/ lookup + * - concurrent tty removal from driver table + */ +struct tty_struct *tty_kopen_exclusive(dev_t device) +{ + return tty_kopen(device, 0); +} +EXPORT_SYMBOL_GPL(tty_kopen_exclusive); + +/** + * tty_kopen_shared - open a tty device for shared in-kernel use + * @device: dev_t of device to open + * + * Opens an already existing tty for in-kernel use. Compared to + * tty_kopen_exclusive() above it doesn't ensure to be the only user. + * + * Locking is identical to tty_kopen() above. + */ +struct tty_struct *tty_kopen_shared(dev_t device) +{ + return tty_kopen(device, 1); +} +EXPORT_SYMBOL_GPL(tty_kopen_shared); /** * tty_open_by_driver - open a tty device @@ -2485,15 +2591,36 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd, return tty->ops->tiocmset(tty, set, clear); } +/** + * tty_get_icount - get tty statistics + * @tty: tty device + * @icount: output parameter + * + * Gets a copy of the tty's icount statistics. + * + * Locking: none (up to the driver) + */ +int tty_get_icount(struct tty_struct *tty, + struct serial_icounter_struct *icount) +{ + memset(icount, 0, sizeof(*icount)); + + if (tty->ops->get_icount) + return tty->ops->get_icount(tty, icount); + else + return -EINVAL; +} +EXPORT_SYMBOL_GPL(tty_get_icount); + static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) { - int retval = -EINVAL; struct serial_icounter_struct icount; - memset(&icount, 0, sizeof(icount)); - if (tty->ops->get_icount) - retval = tty->ops->get_icount(tty, &icount); + int retval; + + retval = tty_get_icount(tty, &icount); if (retval != 0) return retval; + if (copy_to_user(arg, &icount, sizeof(icount))) return -EFAULT; return 0; @@ -2884,7 +3011,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, static int this_tty(const void *t, struct file *file, unsigned fd) { - if (likely(file->f_op->read != tty_read)) + if (likely(file->f_op->read_iter != tty_read)) return 0; return file_tty(file) != t ? 0 : fd + 1; } |