kernel.git/drivers/tty/tty_io.c, branch linux-4.13.y

pty: Repair TIOCGPTPEER

2017-08-24T20:23:03Z

The implementation of TIOCGPTPEER has two issues. When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong vfsmount is passed to dentry_open. Which results in the kernel displaying the wrong pathname for the peer. The second is simply by caching the vfsmount and dentry of the peer it leaves them open, in a way they were not previously Which because of the inreased reference counts can cause unnecessary behaviour differences resulting in regressions. To fix these move the ioctl into tty_io.c at a generic level allowing the ioctl to have access to the struct file on which the ioctl is being called. This allows the path of the slave to be derived when opening the slave through TIOCGPTPEER instead of requiring the path to the slave be cached. Thus removing the need for caching the path. A new function devpts_ptmx_path is factored out of devpts_acquire and used to implement a function devpts_mntget. The new function devpts_mntget takes a filp to perform the lookup on and fsi so that it can confirm that the superblock that is found by devpts_ptmx_path is the proper superblock. v2: Lots of fixes to make the code actually work v3: Suggestions by Linus - Removed the unnecessary initialization of filp in ptm_open_peer - Simplified devpts_ptmx_path as gotos are no longer required [ This is the fix for the issue that was reverted in commit 143c97cc6529, but this time without breaking 'pbuilder' due to increased reference counts - Linus ] Fixes: 54ebbfb16034 ("tty: add TIOCGPTPEER ioctl") Reported-by: Christian Brauner Reported-and-tested-by: Stefan Lippers-Hollmann Signed-off-by: "Eric W. Biederman" Signed-off-by: Linus Torvalds

tty: add function to convert device name to number

2017-06-27T07:08:47Z

The function converts strings like ttyS0 and ttyUSB0 to dev_t like (4, 64) and (188, 0). It does this by scanning tty_drivers list for corresponding device name and index. If the driver is not registered, this function returns -ENODEV. It also acquires tty_mutex. Signed-off-by: Okash Khawaja Signed-off-by: Greg Kroah-Hartman

tty: export tty_open_by_driver

2017-05-16T12:04:49Z

This exports tty_open_by_driver so that it can be called from other places inside the kernel. The checks for null file pointer are based on Alan Cox's patch here: http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1215095.html. Description below is quoted from it: "[RFC] tty_port: allow a port to be opened with a tty that has no file handle Let us create tty objects entirely in kernel space. Untested proposal to show why all the ideas around rewriting half the uart stack are not needed. With this a kernel created non file backed tty object could be used to handle data, and set terminal modes. Not all ldiscs can cope with this as N_TTY in particular has to work back to the fs/tty layer. The tty_port code is however otherwise clean of file handles as far as I can tell as is the low level tty port write path used by the ldisc, the configuration low level interfaces and most of the ldiscs. Currently you don't have any exposure to see tty hangups because those are built around the file layer. However a) it's a fixed port so you probably don't care about that b) if you do we can add a callback and c) you almost certainly don't want the userspace tear down/rebuild behaviour anyway. This should however be sufficient if we wanted for example to enumerate all the bluetooth bound fixed ports via ACPI and make them directly available. It doesn't deal with the case of a user opening a port that's also kernel opened and that would need some locking out (so it returned EBUSY if bound to a kernel device of some kind). That needs resolving along with how you "up" or "down" your new bluetooth device, or enumerate it while providing the existing tty API to avoid regressions (and to debug)." The exported funtion is used later in this patch set to gain access to tty_struct. [changed export symbol level - gkh] Signed-off-by: Okash Khawaja Reviewed-by: Samuel Thibault Signed-off-by: Greg Kroah-Hartman

tty: split job control support into a file of its own

2017-04-18T16:01:52Z

This makes it easier for job control to become optional and/or usable independently from tty_io.c, as well as providing a nice purpose separation. No logical changes from this patch. Signed-off-by: Nicolas Pitre Signed-off-by: Greg Kroah-Hartman

console: move console_init() out of tty_io.c

2017-04-18T16:01:52Z

All the console driver handling code lives in printk.c. Move console_init() there as well so console support can still be used when the TTY code is configured out. No logical changes from this patch. Signed-off-by: Nicolas Pitre Signed-off-by: Greg Kroah-Hartman

tty: fix comment typo s/repsonsible/responsible/

2017-04-08T16:54:07Z

Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

tty: reset termios state on device registration

2017-03-31T09:37:13Z

Free any saved termios data when registering a tty device so that the termios state is reset when reusing a minor number. This is useful for hot-pluggable buses such as USB where it does not make much sense to reuse saved termios data from an unrelated device when a new device is later plugged in. This specifically avoids a situation where the new device does not have the carrier-detect signal wired, but the saved termios state has CLOCAL cleared, effectively preventing the port from being opened in blocking mode as noted by Jan Kundrát . Note that clearing the saved data at deregistration would not work as the device could still be open. Also note that the termios data is not reset for drivers with TTY_DRIVER_DYNAMIC_ALLOC set (e.g. legacy pty) as their character device is registered at driver registration and could theoretically already have been opened (and pty termios state is never saved anyway). Reported-by: Jan Kundrát Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

tty: drop obsolete termios_locked comments

2017-03-31T09:37:13Z

Drop comments about tty-driver termios_locked structures, which have been outdated since commit fe6e29fdb1a7 ("tty: simplify ktermios allocation"). Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

tty: close race between device register and open

2017-03-31T09:37:13Z

The tty class device is currently not registered until after the character device has been registered thereby leaving a small window were a racing open could end up with a NULL tty->dev pointer due to the class-device lookup failing in alloc_tty_struct. Close this race by registering the class device before the character device while making sure to defer the user-space uevent notification until after the character device has been registered. Note that some tty drivers expect a valid tty->dev and would misbehave or crash otherwise. Some line disciplines also currently dereference the class device unconditionally despite the fact that not every tty is guaranteed to have one (Unix98 pty), but this is being fixed separately. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

drivers/tty: Convert remaining uses of pr_warning to pr_warn

2017-03-17T05:14:00Z

To enable eventual removal of pr_warning This makes pr_warn use consistent for drivers/tty Prior to this patch, there were 2 uses of pr_warning and 23 uses of pr_warn in drivers/tty Signed-off-by: Joe Perches Signed-off-by: Greg Kroah-Hartman