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path: root/drivers/tty/tty_ioctl.c
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2015-02-02tty: Remove external interface for tty_set_termios()Peter Hurley1-2/+1
tty_set_termios() is an internal helper intended for file scope use. UART drivers which are capable of driving the RTS pin must properly handle the tiocmset() method, regardless of termios settings. A failure to do so is a UART driver bug and should be fixed there. Do not use this interface to workaround UART driver bugs. Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: <linux-bluetooth@vger.kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05tty: Call methods in modern stylePeter Hurley1-2/+2
The use of older function ptr calling style, (*fn)(), makes static analysis more error-prone; replace with modern fn() style. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05tty: Move pty-specific set_termios() handling to pty driverPeter Hurley1-31/+1
Packet mode is unique to the pty driver; move the packet mode state change code from the generic tty ioctl handler to the pty driver. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05tty: WARN for attempted set_termios() of pty masterPeter Hurley1-0/+4
The pty master's termios should never be set; currently, all code paths which call the driver's set_termios() method ensure that the pty slave's termios is being set. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Reviewed-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23tty: Hold termios_rwsem for tcflow(TCIxxx)Peter Hurley1-3/+7
While transmitting a START/STOP char for tcflow(TCION/TCIOFF), prevent a termios change. Otherwise, a garbage in-band flow control char may be sent, if the termios change overlaps the transmission setup. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23tty: Move and rename send_prio_char() as tty_send_xchar()Peter Hurley1-31/+2
Relocate the file-scope function, send_prio_char(), as a global helper tty_send_xchar(). Remove the global declarations for tty_write_lock()/tty_write_unlock(), as these are file-scope only now. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23tty: Serialize tcflow() with other tty flow control changesPeter Hurley1-2/+6
Use newly-introduced tty->flow_lock to serialize updates to tty->flow_stopped (via tcflow()) and with concurrent tty flow control changes from other sources. Merge the storage for ->stopped and ->flow_stopped, now that both flags are serialized by ->flow_lock. The padding bits are necessary to force the compiler to allocate the type specified; otherwise, gcc will ignore the type specifier and allocate the minimum number of bytes necessary to store the bitfield. In turn, this would allow Alpha EV4 and EV5 cpus to corrupt adjacent byte storage because those cpus use RMW to store byte and short data. gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields smaller than unsigned long on ia64, ppc64, hppa64 and sparc64, thus requiring more than unsigned int storage (which would otherwise be sufficient to workaround the Alpha non-atomic byte/short storage problem). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-08tty: fix typo in comment of tty_termios_encode_baud_rateMatthias Brugger1-1/+1
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-25tty: Fix SIGTTOU not sent with tcflush()Peter Hurley1-0/+3
Commit 'e7f3880cd9b98c5bf9391ae7acdec82b75403776' tty: Fix recursive deadlock in tty_perform_flush() introduced a regression where tcflush() does not generate SIGTTOU for background process groups. Make sure ioctl(TCFLSH) calls tty_check_change() when invoked from the line discipline. Cc: stable@vger.kernel.org # v3.10+ Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23tty: Only guarantee termios read safety for throttle/unthrottlePeter Hurley1-4/+4
No tty driver modifies termios during throttle() or unthrottle(). Therefore, only read safety is required. However, tty_throttle_safe and tty_unthrottle_safe must still be mutually exclusive; introduce throttle_mutex for that purpose. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23tty: Convert termios_mutex to termios_rwsemPeter Hurley1-45/+45
termios is commonly accessed unsafely (especially by N_TTY) because the existing mutex forces exclusive access. Convert existing usage. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-15tty: Fix unsafe bit ops in tty_throttle_safe/unthrottle_safePeter Hurley1-2/+2
tty->flags needs to be atomically modified. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18tty: Fix recursive deadlock in tty_perform_flush()Peter Hurley1-9/+19
tty_perform_flush() can deadlock when called while holding a line discipline reference. By definition, all ldisc drivers hold a ldisc reference, so calls originating from ldisc drivers must not block for a ldisc reference. The deadlock can occur when: CPU 0 | CPU 1 | tty_ldisc_ref(tty) | .... | <line discipline halted> tty_ldisc_ref_wait(tty) | | CPU 0 cannot progess because it cannot obtain an ldisc reference with the line discipline has been halted (thus no new references are granted). CPU 1 cannot progress because an outstanding ldisc reference has not been released. An in-tree call-tree audit of tty_perform_flush() [1] shows 5 ldisc drivers calling tty_perform_flush() indirectly via n_tty_ioctl_helper() and 2 ldisc drivers calling directly. A single tty driver safely uses the function. [1] Recursive usage: /* These functions are line discipline ioctls and thus * recursive wrt line discipline references */ tty_perform_flush() - ./drivers/tty/tty_ioctl.c n_tty_ioctl_helper() hci_uart_tty_ioctl(default) - drivers/bluetooth/hci_ldisc.c (N_HCI) n_hdlc_tty_ioctl(default) - drivers/tty/n_hdlc.c (N_HDLC) gsmld_ioctl(default) - drivers/tty/n_gsm.c (N_GSM0710) n_tty_ioctl(default) - drivers/tty/n_tty.c (N_TTY) gigaset_tty_ioctl(default) - drivers/isdn/gigaset/ser-gigaset.c (N_GIGASET_M101) ppp_synctty_ioctl(TCFLSH) - drivers/net/ppp/pps_synctty.c ppp_asynctty_ioctl(TCFLSH) - drivers/net/ppp/ppp_async.c Non-recursive use: tty_perform_flush() - drivers/tty/tty_ioctl.c ipw_ioctl(TCFLSH) - drivers/tty/ipwireless/tty.c /* This function is a tty i/o ioctl method, which * is invoked by tty_ioctl() */ Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18TTY: do not warn about setting speed via SPD_*Jiri Slaby1-28/+0
The warning is there since 2.1.69 and we have not seen anybody reporting it in the past decade. Remove the warning now. tty_get_baud_rate can now be inline. This gives us one less EXPORT_SYMBOL. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18tty: Add safe tty throttle/unthrottle functionsPeter Hurley1-0/+64
The tty driver can become stuck throttled due to race conditions between throttle and unthrottle, when the decision to throttle or unthrottle is conditional. The following example helps to illustrate the race: CPU 0 | CPU 1 | if (condition A) | | <processing such that A not true> | if (!condition A) | unthrottle() throttle() | | Note the converse is also possible; ie., CPU 0 | CPU 1 | | if (!condition A) <processing such that A true> | if (condition A) | throttle() | | unthrottle() | Add new throttle/unthrottle functions based on the familiar model of task state and schedule/wake. For example, while (1) { tty_set_flow_change(tty, TTY_THROTTLE_SAFE); if (!condition) break; if (!tty_throttle_safe(tty)) break; } __tty_set_flow_change(tty, 0); In this example, if an unthrottle occurs after the condition is evaluated but before tty_throttle_safe(), then tty_throttle_safe() will return non-zero, looping and forcing the re-evaluation of condition. Reported-by: Vincent Pillet <vincentx.pillet@intel.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-04tty: set_termios/set_termiox should not return -EINTROleg Nesterov1-2/+2
See https://bugzilla.redhat.com/show_bug.cgi?id=904907 read command causes bash to abort with double free or corruption (out). A simple test-case from Roman: // Compile the reproducer and send sigchld ti that process. // EINTR occurs even if SA_RESTART flag is set. void handler(int sig) { } main() { struct sigaction act; act.sa_handler = handler; act.sa_flags = SA_RESTART; sigaction (SIGCHLD, &act, 0); struct termio ttp; ioctl(0, TCGETA, &ttp); while(1) { if (ioctl(0, TCSETAW, ttp) < 0) { if (errno == EINTR) { fprintf(stderr, "BUG!"); return(1); } } } } Change set_termios/set_termiox to return -ERESTARTSYS to fix this particular problem. I didn't dare to change other EINTR's in drivers/tty/, but they look equally wrong. Reported-by: Roman Rakus <rrakus@redhat.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-18tty: Add driver unthrottle in ioctl(...,TCFLSH,..).Ilya Zykov1-2/+6
Regression 'tty: fix "IRQ45: nobody cared"' Regression commit 7b292b4bf9a9d6098440d85616d6ca4c608b8304 Function reset_buffer_flags() also invoked during the ioctl(...,TCFLSH,..). At the time of request we can have full buffers and throttled driver too. If we don't unthrottle driver, we can get forever throttled driver, because, after request, we will have empty buffers and throttled driver and there is no place to unthrottle driver. It simple reproduce with "pty" pair then one side sleep on tty->write_wait, and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up. Signed-off-by: Ilya Zykov <ilya@ilyx.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-25tty: pty - Move TIOCPKT handling into pty.cCyrill Gorcunov1-21/+0
Since this ioctl is for pty devices only move it to pty.c. v2: - drop PTY_TYPE_MASTER test since it's master peer ioctl anyway (by jslaby@) Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Pavel Emelyanov <xemul@parallels.com> CC: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-17tty: Fix up PPC fallout from the termios moveAlan Cox1-12/+12
This fixes up the problem Stephen Rothwell reported when trying to merge -next Signed-off-by: Alan Cox <alan@linux.intel.com> Reported-by: Stephen Rothwell <sfr@cab.auug.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-16tty: move the termios object into the ttyAlan Cox1-62/+62
This will let us sort out a whole pile of tty related races. The alternative would be to keep points and refcount the termios objects. However 1. They are tiny anyway 2. Many devices don't use the stored copies 3. We can remove a pty special case Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-28Remove all #inclusions of asm/system.hDavid Howells1-1/+0
Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com>
2011-10-18tty: Support compat_ioctl get/set termios_lockedThomas Meyer1-0/+17
When running a Fedora 15 (x86) on an x86_64 kernel, in the boot process plymouthd complains about those two missing ioctls: [ 2.581783] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005457){t:'T';sz:0} arg(ffb6a5d0) on /dev/tty1 [ 2.581803] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005456){t:'T';sz:0} arg(ffb6a680) on /dev/tty1 both ioctl functions work on the 'struct termios' resp. 'struct termios2', which has the same size (36 bytes resp. 44 bytes) on x86 and x86_64, so it's just a matter of converting the pointer from userland. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-23Merge branch 'tty-next' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 * 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (48 commits) serial: 8250_pci: add support for Cronyx Omega PCI multiserial board. tty/serial: Fix break handling for PORT_TEGRA tty/serial: Add explicit PORT_TEGRA type n_tracerouter and n_tracesink ldisc additions. Intel PTI implementaiton of MIPI 1149.7. Kernel documentation for the PTI feature. export kernel call get_task_comm(). tty: Remove to support serial for S5P6442 pch_phub: Support new device ML7223 8250_pci: Add support for the Digi/IBM PCIe 2-port Adapter ASoC: Update cx20442 for TTY API change pch_uart: Support new device ML7223 IOH parport: Use request_muxed_region for IT87 probe and lock tty/serial: add support for Xilinx PS UART n_gsm: Use print_hex_dump_bytes drivers/tty/moxa.c: Put correct tty value TTY: tty_io, annotate locking functions TTY: serial_core, remove superfluous set_task_state TTY: serial_core, remove invalid test Char: moxa, fix locking in moxa_write ... Fix up trivial conflicts in drivers/bluetooth/hci_ldisc.c and drivers/tty/serial/Makefile. I did the hci_ldisc thing as an evil merge, cleaning things up.
2011-04-26Merge branch 'master' into for-nextJiri Kosina1-3/+3
Fast-forwarded to current state of Linus' tree as there are patches to be applied for files that didn't exist on the old branch.
2011-04-19tty: remove invalid location line in file headerJovi Zhang1-2/+0
remove invalid location line in each file header after location moved from driver/char to driver/tty Signed-off-by: Jovi Zhang <bookjovi@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-12tty: fix typo in descripton of tty_termios_encode_baud_rateUwe Kleine-König1-1/+1
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-31Fix common misspellingsLucas De Marchi1-3/+3
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-02-17tty: add a helper for setting termios data from kernel sideAlan Cox1-5/+9
This basically encapsulates the small bit of locking knowledge needed. While we are at it make sure we blow up on any more abusers and unsafe misuses of ioctl for this kind of stuff. We change the function to return an argument as at some point it needs to honour the POSIX 'I asked for changes but got none of them' error reporting corner case. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-05TTY: create drivers/tty and move the tty core files thereGreg Kroah-Hartman1-0/+1179
The tty code should be in its own subdirectory and not in the char driver with all of the cruft that is currently there. Based on work done by Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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