On Tue, Jun 25, 2019 at 07:11:46PM +0300, Arseny Maslennikov wrote: > This patch series introduces TTY keyboard status request, a feature of > the n_tty line discipline that reserves a character in struct termios > (^T by default) and reacts to it by printing a short informational line > to the terminal and sending a Unix signal to the tty's foreground > process group. The processes may, in response to the signal, output a > textual description of what they're doing. > > The feature has been present in a similar form at least in > Free/Open/NetBSD; it would be nice to have something like this in Linux > as well. There is an LKML thread[1] where users have previously > expressed the rationale for this. > > The current implementation does not break existing kernel API in any > way, since, fortunately, all the architectures supported by the kernel > happen to have at least 1 free byte in the termios control character > array. > > The series should cleanly apply to tty-next. > > To thoroughly test these, one might need at least a patched stty among > other tools, so I've brought up a simple initrd generator[2] which can > be used to create a lightweight environment to boot up in a VM and to > fiddle with. > > [1] https://lore.kernel.org/lkml/1415200663.3247743.187387481.75CE9317@xxxxxxxxxxxxxxxxxxxxxxxxxxx/ > [2] https://github.com/porrided/tty-kb-status-userspace > > v2 <- v1: removed useless debugging bits. > > Discussion of v1: > https://lore.kernel.org/lkml/20190605081906.28938-1-ar@xxxxxxxxx/ > > Arseny Maslennikov (7): > signal.h: Define SIGINFO on all architectures > tty: termios: Reserve space for VSTATUS in .c_cc > n_tty: Send SIGINFO to fg pgrp on status request character > linux/signal.h: Ignore SIGINFO by default in new tasks > tty: Add NOKERNINFO lflag to termios > n_tty: ->ops->write: Cut core logic out to a separate function > n_tty: Provide an informational line on VSTATUS receipt > > arch/alpha/include/asm/termios.h | 4 +- > arch/alpha/include/uapi/asm/termbits.h | 2 + > arch/arm/include/uapi/asm/signal.h | 1 + > arch/h8300/include/uapi/asm/signal.h | 1 + > arch/ia64/include/asm/termios.h | 4 +- > arch/ia64/include/uapi/asm/signal.h | 1 + > arch/ia64/include/uapi/asm/termbits.h | 2 + > arch/m68k/include/uapi/asm/signal.h | 1 + > arch/mips/include/asm/termios.h | 4 +- > arch/mips/include/uapi/asm/signal.h | 1 + > arch/mips/include/uapi/asm/termbits.h | 2 + > arch/parisc/include/asm/termios.h | 4 +- > arch/parisc/include/uapi/asm/signal.h | 1 + > arch/parisc/include/uapi/asm/termbits.h | 2 + > arch/powerpc/include/asm/termios.h | 4 +- > arch/powerpc/include/uapi/asm/signal.h | 1 + > arch/powerpc/include/uapi/asm/termbits.h | 2 + > arch/s390/include/asm/termios.h | 4 +- > arch/s390/include/uapi/asm/signal.h | 1 + > arch/sparc/include/asm/termios.h | 4 +- > arch/sparc/include/uapi/asm/signal.h | 2 + > arch/sparc/include/uapi/asm/termbits.h | 2 + > arch/x86/include/uapi/asm/signal.h | 1 + > arch/xtensa/include/uapi/asm/signal.h | 1 + > arch/xtensa/include/uapi/asm/termbits.h | 2 + > drivers/tty/Makefile | 3 +- > drivers/tty/n_tty.c | 70 ++++- > drivers/tty/n_tty_status.c | 337 +++++++++++++++++++++++ > include/asm-generic/termios.h | 4 +- > include/linux/sched.h | 7 + > include/linux/signal.h | 5 +- > include/linux/tty.h | 7 +- > include/uapi/asm-generic/signal.h | 1 + > include/uapi/asm-generic/termbits.h | 2 + > 34 files changed, 457 insertions(+), 33 deletions(-) > create mode 100644 drivers/tty/n_tty_status.c > > Date: Tue, 25 Jun 2019 19:11:46 +0300 Ping. The series should cleanly apply to 5.3-rc2 and to tty-next as of writing this email.
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