[PATCH v2 0/3] support for the kernel 7.1 modifier-aware KT_CSI keysym type

Linux kernel 7.1 introduces modifier-aware escape sequence generation
for the console keyboard:

  4af70f151671 ("vt: add modifier support to cursor keys")
  5cba06c71c71 ("vt: add KT_CSI keysym type for modifier-aware CSI sequences")
  c1d2deb6492f ("vt: add fallback to plain map for modifier-aware key types")

The new KT_CSI keysym type produces xterm-style CSI tilde sequences
(ESC [ n ~, or ESC [ n ; mod ~ when Shift/Alt/Control are held) with
the modifier state encoded at runtime. A single plain map entry covers
all modifier combinations, instead of consuming a func_table string
slot per combination.

This series adds the userspace counterpart:

Patch 1 teaches libkeymap the Csi_* keysym names (Csi_Home, Csi_End,
Csi_Delete, Csi_Insert, Csi_PgUp, Csi_PgDn, Csi_F1..Csi_F20, matching
the kernel UAPI values) and documents modifier-aware keys in
keymaps(5).

Patch 2 adds a contrib script (with optional systemd unit) that
reconciles the "linux" terminfo entry with the loaded keymap: F1-F5
in CSI form and Backtab as ESC [ Z are not what the stock terminfo
entry expects.

Patch 3 keeps the default keymaps on their traditional bindings and
adds an opt-in overlay (linux-keys-csi.inc) that switches the function
and navigation keys to the Csi_* keysyms. The boot script applies it
only when the running kernel supports KT_CSI, so nothing changes on
older kernels.

Changes since v1 (addressing Alexey's review):

 - Patch 1: bump NR_TYPES in summary.c so KT_CSI appears in
   "dumpkeys --long-info".

 - Patch 3: reworked from an in-place conversion (which broke pre-7.1
   systems) into the opt-in overlay described above.

v1: https://lore.kernel.org/kbd/[email protected]

Tested with make check, a staged "make install" (overlay installs and
resolves by name), and the terminfo script exercised live on Fedora 43.

Nicolas Pitre (3):
  libkeymap: add support for KT_CSI keysym type
  Add kbd-terminfo-fixup script and systemd service
  keymaps: add opt-in CSI overlay and load it when the kernel supports
    it

 .gitignore                                   |   1 +
 Makefile.am                                  |  16 +
 configure.ac                                 |  18 ++
 contrib/kbd-terminfo-fixup                   | 303 +++++++++++++++++++
 contrib/kbd-terminfo-fixup.service.in        |  13 +
 data/keymaps/i386/include/linux-keys-csi.inc |  83 +++++
 docs/man/man5/keymaps.5                      |  77 +++++
 src/libkeymap/ksyms.c                        |   3 +-
 src/libkeymap/summary.c                      |   2 +-
 src/libkeymap/syms.ktyp.h                    |  39 +++
 tests/data/keymap0-summary.txt               |  26 ++
 11 files changed, 579 insertions(+), 2 deletions(-)
 create mode 100755 contrib/kbd-terminfo-fixup
 create mode 100644 contrib/kbd-terminfo-fixup.service.in
 create mode 100644 data/keymaps/i386/include/linux-keys-csi.inc

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2.54.0