| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
Signed-off-by: Al Viro <[email protected]>
|
|
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.
Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.
This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.
Cc: Jiri Slaby <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: David Sterba <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Eric Anholt <[email protected]>
Cc: Stefan Wahren <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Ray Jui <[email protected]>
Cc: Scott Branden <[email protected]>
Cc: [email protected]
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Joachim Eastwood <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Tobias Klauser <[email protected]>
Cc: Russell King <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Richard Genoud <[email protected]>
Cc: Alexander Shiyan <[email protected]>
Cc: Baruch Siach <[email protected]>
Cc: "Maciej W. Rozycki" <[email protected]>
Cc: "Uwe Kleine-König" <[email protected]>
Cc: Pat Gefre <[email protected]>
Cc: "Guilherme G. Piccoli" <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: Vladimir Zapolskiy <[email protected]>
Cc: Sylvain Lemieux <[email protected]>
Cc: Carlo Caione <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Liviu Dudau <[email protected]>
Cc: Sudeep Holla <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: Andy Gross <[email protected]>
Cc: David Brown <[email protected]>
Cc: "Andreas Färber" <[email protected]>
Cc: Kevin Cernekee <[email protected]>
Cc: Laxman Dewangan <[email protected]>
Cc: Thierry Reding <[email protected]>
Cc: Jonathan Hunter <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Patrice Chotard <[email protected]>
Cc: Maxime Coquelin <[email protected]>
Cc: Alexandre Torgue <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Peter Korsgaard <[email protected]>
Cc: Timur Tabi <[email protected]>
Cc: Tony Prisk <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: "Sören Brinkmann" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Kate Stewart <[email protected]>
Cc: Philippe Ombredanne <[email protected]>
Cc: Jiri Slaby <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging/IIO driver updates from Greg KH:
"Here is the big staging and IIO driver update for 4.14-rc1.
Lots of staging driver fixes and cleanups, including some reorginizing
of the lustre header files to try to impose some sanity on what is,
and what is not, the uapi for that filesystem.
There are some tty core changes in here as well, as the speakup
drivers need them, and that's ok with me, they are sane and the
speakup code is getting nicer because of it.
There is also the addition of the obiligatory new wifi driver, just
because it has been a release or two since we added our last one...
Other than that, lots and lots of small coding style fixes, as usual.
All of these have been in linux-next for a while with no reported
issues"
* tag 'staging-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (612 commits)
staging:rtl8188eu:core Fix remove unneccessary else block
staging: typec: fusb302: make structure fusb302_psy_desc static
staging: unisys: visorbus: make two functions static
staging: fsl-dpaa2/eth: fix off-by-one FD ctrl bitmaks
staging: r8822be: Simplify deinit_priv()
staging: r8822be: Remove some dead code
staging: vboxvideo: Use CONFIG_DRM_KMS_FB_HELPER to check for fbdefio availability
staging:rtl8188eu Fix comparison to NULL
staging: rts5208: rename mmc_ddr_tunning_rx_cmd to mmc_ddr_tuning_rx_cmd
Staging: Pi433: style fix - tabs and spaces
staging: pi433: fix spelling mistake: "preample" -> "preamble"
staging:rtl8188eu:core Fix Code Indent
staging: typec: fusb302: Export current-limit through a power_supply class dev
staging: typec: fusb302: Add support for USB2 charger detection through extcon
staging: typec: fusb302: Use client->irq as irq if set
staging: typec: fusb302: Get max snk mv/ma/mw from device-properties
staging: typec: fusb302: Set max supply voltage to 5V
staging: typec: tcpm: Add get_current_limit tcpc_dev callback
staging:rtl8188eu Use __func__ instead of function name
staging: lustre: coding style fixes found by checkpatch.pl
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the big tty/serial driver update for 4.14-rc1.
Well, not all that big, just a number of small serial driver fixes,
and a new serial driver. Also in here are some much needed goldfish
tty driver (emulator) fixes to try to get that codebase under control.
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (94 commits)
tty: goldfish: Implement support for kernel 'earlycon' parameter
tty: goldfish: Use streaming DMA for r/w operations on Ranchu platforms
tty: goldfish: Refactor constants to better reflect their nature
serial: 8250_port: Remove useless NULL checks
earlycon: initialise baud field of earlycon device structure
tty: hvcs: make ktermios const
pty: show associative slave of ptmx in fdinfo
tty: n_gsm: Add compat_ioctl
tty: hvcs: constify vio_device_id
tty: hvc_vio: constify vio_device_id
tty: mips_ejtag_fdc: constify mips_cdmm_device_id
Introduce 8250_men_mcb
mcb: introduce mcb_get_resource()
serial: imx: Avoid post-PIO cleanup if TX DMA is started
tty: serial: imx: disable irq after suspend
serial: 8250_uniphier: add suspend/resume support
serial: 8250_uniphier: use CHAR register for canary to detect power-off
serial: 8250_uniphier: fix serial port index in private data
serial: 8250: of: Add new port type for MediaTek BTIF controller on MT7622/23 SoC
dt-bindings: serial: 8250: Add MediaTek BTIF controller bindings
...
|
|
This patch adds "tty-index" field to /proc/PID/fdinfo/N if N
specifies /dev/ptmx. The field shows the index of associative
slave pts.
Though a minor number is given for each pts instance, ptmx is not.
It means there is no way in user-space to know the association between
file descriptors for pts/n and ptmx. (n = 0, 1, ...)
This is different from pipe. About pipe such association can be solved
by inode of pipefs.
Providing the way to know the association between pts/n and ptmx helps
users understand the status of running system. lsof can utilize this field.
Signed-off-by: Masatake YAMATO <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Since we have tty_kopen, we no longer need to export tty_open_by_driver.
This patch makes this function static.
Signed-off-by: Okash Khawaja <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
The commit 12e84c71b7d4 ("tty: export tty_open_by_driver") exports
tty_open_by_device to allow tty to be opened from inside kernel which
works fine except that it doesn't handle contention with user space or
another kernel-space open of the same tty. For example, opening a tty
from user space while it is kernel opened results in failure and a
kernel log message about mismatch between tty->count and tty's file
open count.
This patch makes kernel access to tty exclusive, so that if a user
process or kernel opens a kernel opened tty, it gets -EBUSY. It does
this by adding TTY_KOPENED flag to tty->flags. When this flag is set,
tty_open_by_driver returns -EBUSY. Instead of overloading
tty_open_by_driver for both kernel and user space, this
patch creates a separate function tty_kopen which closely follows
tty_open_by_driver. tty_kclose closes the tty opened by tty_kopen.
To address the mismatch between tty->count and #fd's, this patch adds
#kopen's to the count before comparing it with tty->count. That way
check_tty_count reflects correct usage count.
Returning -EBUSY on tty open is a change in the interface. I have
tested this with minicom, picocom and commands like "echo foo >
/dev/ttyS0". They all correctly report "Device or resource busy" when
the tty is already kernel opened.
Signed-off-by: Okash Khawaja <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>
Reported-and-tested-by: Stefan Lippers-Hollmann <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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/[email protected]/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 <[email protected]>
Reviewed-by: Samuel Thibault <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Signed-off-by: Thadeu Lima de Souza Cascardo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>.
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 <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Drop comments about tty-driver termios_locked structures, which have
been outdated since commit fe6e29fdb1a7 ("tty: simplify ktermios
allocation").
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
<linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
<linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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).
Signed-off-by: Alan Cox <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-By: Sebastian Reichel <[email protected]>
Signed-off-by: Rob Herring <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
For in-kernel tty users, we need to be able to create and destroy
'struct tty' that are not associated with a file. The creation side is
fine, but tty_release() needs to be split into the file handle portion
and the struct tty portion. Introduce a new function, tty_release_struct,
to handle just the destroying of a struct tty.
Signed-off-by: Rob Herring <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-By: Sebastian Reichel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
We want the pty fixes in here as well so that patches can build on it.
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
noctty was removed as a parameter by commit 11e1d4aa4da
("tty: Consolidate noctty check in tty_open()").
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
TTY_NUMBER() has been unused since v2.5.71; removed by
"[PATCH] callout removal: callout is gone".
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Abstract TTY_IO_ERROR status test treewide with tty_io_error().
NB: tty->flags uses atomic bit ops; replace non-atomic bit test
with test_bit().
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
This is more prep-work for the upcoming pty changes. Still just code
cleanup with no actual semantic changes.
This removes a bunch pointless complexity by just having the slave pty
side remember the dentry associated with the devpts slave rather than
the inode. That allows us to remove all the "look up the dentry" code
for when we want to remove it again.
Together with moving the tty pointer from "inode->i_private" to
"dentry->d_fsdata" and getting rid of pointless inode locking, this
removes about 30 lines of code. Not only is the end result smaller,
it's simpler and easier to understand.
The old code, for example, depended on the d_find_alias() to not just
find the dentry, but also to check that it is still hashed, which in
turn validated the tty pointer in the inode.
That is a _very_ roundabout way to say "invalidate the cached tty
pointer when the dentry is removed".
The new code just does
dentry->d_fsdata = NULL;
in devpts_pty_kill() instead, invalidating the tty pointer rather more
directly and obviously. Don't do something complex and subtle when the
obvious straightforward approach will do.
The rest of the patch (ie apart from code deletion and the above tty
pointer clearing) is just switching the calling convention to pass the
dentry or file pointer around instead of the inode.
Cc: Eric Biederman <[email protected]>
Cc: Peter Anvin <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Peter Hurley <[email protected]>
Cc: Serge Hallyn <[email protected]>
Cc: Willy Tarreau <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Greg KH <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Florian Weimer <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock")
fixed a tty reference counting problem introduced in
commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"),
so v4.5.0 is correct.
However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the
relevant code for 4.6-rc1; correct the merge.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
User-Mode Linux supplies an alternate TTY_MAJOR driver for stdio console,
so the noctty check in tty_open() must apply only to VT driver tty0
devnode and not the UML console driver tty0 devnode.
Fixes: 11e1d4aa4da1 ("tty: Consolidate noctty checks in tty_open()")
Reported-by: Richard Weinberger <[email protected]>
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
A small race window exists which allows signal-driven async i/o to be
enabled for the tty when the file ptr has already been hungup and
signal-driven i/o has been disabled:
CPU 0 CPU 1
----- ------
ioctl_fioasync(on)
filp->f_op->fasync(on) __tty_hangup()
tty_fasync(on) tty_lock()
tty_lock() ...
. filp->f_op = &hung_up_tty_fops;
(waiting) __tty_fasync(off)
. tty_unlock()
/* gets tty lock */
/* enables FASYNC */
Check the tty has not been hungup while holding tty_lock.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
VFS uses a two-stage check-and-call method for invoking file_operations
methods, without explicitly snapshotting either the file_operations ptr
or the function ptr. Since the tty core is one of the few VFS users that
changes the f_op file_operations ptr of the file descriptor (when the
tty has been hung up), and since the likelihood of the compiler generating
a reload of either f_op or the function ptr is basically nil, just define
a hung up fasync() file operation that returns an error.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Only the N_TTY line discipline implements the signal-driven i/o
notification enabled/disabled by fcntl(F_SETFL, O_ASYNC). The ldisc
fasync() notification is sent to the ldisc when the enable state has
changed (the tty core is notified via the fasync() VFS file operation).
The N_TTY line discipline used the enable state to change the wakeup
condition (minimum_to_wake = 1) for notifying the signal handler i/o is
available. However, just the presence of data is sufficient and necessary
to signal i/o is available, so changing minimum_to_wake is unnecessary
(and creates a race condition with read() and poll() which may be
concurrently updating minimum_to_wake).
Furthermore, since the kill_fasync() VFS helper performs no action if
the fasync list is empty, calling unconditionally is preferred; if
signal driven i/o just has been disabled, no signal will be sent by
kill_fasync() anyway so notification of the change via the ldisc
fasync() method is superfluous.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Access to tty->tty_files list is always per-tty, never for all ttys
simultaneously. Replace global tty_files_lock spinlock with per-tty
->files_lock. Initialize when the ->tty_files list is inited, in
alloc_tty_struct().
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Move is_ignored() to drivers/tty/tty_io.c and re-declare in file
scope.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Reduce global tty symbols; move and rename tty_ldisc_begin() as
n_tty_init() and redefine the N_TTY ldisc ops as file scope.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
tty_mutex is a core, system-wide lock; there is no reason for any
code outside the tty core to have direct access.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
The line discipline id is stored in the tty's termios; document the
implicit initial value of N_TTY.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Currently, when the tty is hungup, the ldisc is re-instanced; ie., the
current instance is destroyed and a new instance is created. The purpose
of this design was to guarantee a valid, open ldisc for the lifetime of
the tty.
However, now that tty buffers are owned by and have lifetime equivalent
to the tty_port (since v3.10), any data received immediately after the
ldisc is re-instanced may cause continued driver i/o operations
concurrently with the driver's hangup() operation. For drivers that
shutdown h/w on hangup, this is unexpected and usually bad. For example,
the serial core may free the xmit buffer page concurrently with an
in-progress write() operation (triggered by echo).
With the existing stable and robust ldisc reference handling, the
cleaned-up tty_reopen(), the straggling unsafe ldisc use cleaned up, and
the preparation to properly handle a NULL tty->ldisc, the ldisc instance
can be destroyed and only re-instanced when the tty is re-opened.
If the tty was opened as /dev/console or /dev/tty0, the original behavior
of re-instancing the ldisc is retained (the 'reinit' parameter to
tty_ldisc_hangup() is true). This is required since those file descriptors
are never hungup.
This patch has neglible impact on userspace; the tty file_operations ptr
is changed to point to the hungup file operations _before_ the ldisc
instance is destroyed, so only racing file operations might now retrieve
a NULL ldisc reference (which is simply handled as if the hungup file
operation had been called instead -- see "tty: Prepare for destroying
line discipline on hangup").
This resolves a long-standing FIXME and several crash reports.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
tty->ldisc is a ptr to struct tty_ldisc, but unfortunately 'ldisc' is
also used as a parameter or local name to refer to the line discipline
index value (ie, N_TTY, N_GSM, etc.); instead prefer the name used
by the line discipline registration/ref counting functions.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
tty file_operations (read/write/ioctl) wait for the ldisc reference
indefinitely (until ldisc lifetime events, such as hangup or TIOCSETD,
finish). Since hangup now destroys the ldisc and does not instance
another copy, file_operations must now be prepared to receive a NULL
ldisc reference from tty_ldisc_ref_wait():
CPU 0 CPU 1
----- -----
(*f_op->read)() => tty_read()
__tty_hangup()
...
f_op = &hung_up_tty_fops;
...
tty_ldisc_hangup()
tty_ldisc_lock()
tty_ldisc_kill()
tty->ldisc = NULL
tty_ldisc_unlock()
ld = tty_ldisc_ref_wait()
/* ld == NULL */
Instead, the action taken now is to return the same value as if the
tty had been hungup a moment earlier:
CPU 0 CPU 1
----- -----
__tty_hangup()
...
f_op = &hung_up_tty_fops;
(*f_op->read)() => hung_up_tty_read()
return 0;
...
tty_ldisc_hangup()
tty_ldisc_lock()
tty_ldisc_kill()
tty->ldisc = NULL
tty_ldisc_unlock()
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
After the ldisc is released, but before the tty is destroyed, the termios
is saved (in tty_free_termios()); this termios is restored if a new
tty is created on next open(). However, the line discipline is always
reset, which is not obvious in the current method. Instead, reset
as part of the restore.
Restore the original line discipline, which may not have been N_TTY.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Extract the driver lookup and reopen-or-initialize logic into helper
function tty_open_by_driver(). No functional change.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Evaluate the conditions which prevent this tty being the controlling
terminal in one place, just before setting the controlling terminal.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
tty_driver_remove_tty() is only local-scope; declare as static.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
tty_init_termios() never returns an error; re-declare as void. Remove
unnecessary error handling from callers. Remove extern declarations
of tty_free_termios() and free_tty_struct() and re-declare in file
scope.
Signed-off-by: Peter Hurley <[email protected]>
Acked-by: Johan Hovold <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
free_tty_struct() is never called with NULL tty; the two call sites
would already have faulted on earlier access.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
release_tty() leaks the ldisc instance when called directly (rather
than when releasing the file descriptor from tty_release()).
Since tty_ldisc_release() clears tty->ldisc, releasing the ldisc
instance at tty teardown if tty->ldisc is non-null is not in danger
of double-releasing the ldisc.
Remove deinitialize_tty_struct() now that free_tty_struct() always
performs the tty_ldisc_deinit().
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
ioctl(TIOCGETD) retrieves the line discipline id directly from the
ldisc because the line discipline id (c_line) in termios is untrustworthy;
userspace may have set termios via ioctl(TCSETS*) without actually
changing the line discipline via ioctl(TIOCSETD).
However, directly accessing the current ldisc via tty->ldisc is
unsafe; the ldisc ptr dereferenced may be stale if the line discipline
is changing via ioctl(TIOCSETD) or hangup.
Wait for the line discipline reference (just like read() or write())
to retrieve the "current" line discipline id.
Cc: <[email protected]>
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
A small window exists where a tty reopen will observe the tty
just prior to imminent teardown (tty->count == 0); in this case, open()
returns EIO to userspace.
Instead, retry the open after checking for signals and yielding;
this interruptible retry loop allows teardown to commence and initialize
a new tty on retry. Never retry the BSD master pty reopen; there is no
guarantee the pty pair teardown is imminent since the slave file
descriptors may remain open indefinitely.
Signed-off-by: Peter Hurley <[email protected]>
Cc: stable <[email protected]> # 4.4
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
Allow a signal to interrupt the wait for a tty reopen; eg., if
the tty has starting final close and is waiting for the device to
drain.
Signed-off-by: Peter Hurley <[email protected]>
Cc: stable <[email protected]> # 4.4
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|
|
A master pty should never be a controlling tty in Linux; if the
master pty is specified to ioctl(TIOCSCTTY), silently substitute the slave
pty as the controlling tty.
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
|