Lua script to force KDE Konsole to use a blinking vertical I cursor shape by default.

patch_konsolecursor.lua

#!/usr/bin/lua
--[[
Intended for SteamOS v3.4.8 build 20230508.1.

Usage:
  sudo steamos-readonly disable
  sudo chmod +x patch_konsolecursor.lua
  sudo patch_konsolecursor.lua /usr/lib/libkonsoleprivate.so.22.08.2
  sudo steamos-readonly enable

Patch libkonsoleprivate.so.22.08.2 so the cursor is
blinking and non-block shape by default. It does this by
modifying the hex instruction bytes in the .text section
of the shared library binary so no recompiling is necessary.

Relevant byte sequences for locating offsets:
  BlinkingCursorEnabled byte seq:
  31 f6                 xor esi,esi
  48 8d bc 24 30 0c 00  lea rdi,[rsp+0xc30]

  CursorShape byte seq:
  31 f6                 xor esi,esi
  48 8d bc 24 20 0d 00  lea rdi,[rsp+0xd20]
]]

-- Raw byte sequences for libkonsoleprivate.so version 22.08.2
local BlinkingCursorEnabled = "()\x31\xf6\x48\x8d\xbc\x24\x30\x0c\x00"
local CursorShape           = "()\x31\xf6\x48\x8d\xbc\x24\x20\x0d\x00"

local function FindOffset(haystack, needle)
  local found = {}
  for off in haystack:gmatch(needle) do
    table.insert(found, off)
  end
  assert(#found == 1,
    "Could not find exactly one matching offset in shared library!")
  return found[1] - 1
end

local filename = assert(...,
                  "Target Shared Library not provided. eg. libkonsoleprivate.so")
local file = assert(io.open(filename, 'r+'))

local file_content = file:read 'a'

local blink_offset = FindOffset(file_content, BlinkingCursorEnabled)
file:seek('set', blink_offset)
file:write "\x21"           -- xor esi,esi -> and esi,esi   Precondition esi is 1
print "Patched BlinkingCursorEnabled"

local cursorshape_offset = FindOffset(file_content, CursorShape)
file:seek('set', cursorshape_offset)
file:write "\xff\xc6"       -- xor esi,esi -> inc esi       Precondition esi is 0
print "Patched CursorShape"

file:close()