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-- |
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-- fstab.lua |
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-- |
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-- $Id$ |
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-- |
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-- Lua 5.2 module providing a mingw-get setup hook for the MSYS fstab. |
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-- |
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-- Written by Keith Marshall <keithmarshall@users.sourceforge.net> |
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-- Copyright (C) 2014, 2015, MinGW.org Project |
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-- |
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-- |
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-- Permission is hereby granted, free of charge, to any person obtaining a |
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-- copy of this software and associated documentation files (the "Software"), |
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-- to deal in the Software without restriction, including without limitation |
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-- the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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-- and/or sell copies of the Software, and to permit persons to whom the |
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-- Software is furnished to do so, subject to the following conditions: |
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-- |
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-- The above copyright notice and this permission notice shall be included |
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-- in all copies or substantial portions of the Software. |
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-- |
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-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
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-- OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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-- THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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-- FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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-- DEALINGS IN THE SOFTWARE. |
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-- |
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-- |
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-- We begin by initializing a container, for construction of a Lua module |
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-- to encapsulate the content of this source file. |
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-- |
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local M = {} |
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-- |
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-- mingw-get passes the MSYS installation root directory path, |
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-- in the $MSYS_SYSROOT environment variable; from this, we deduce |
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-- the path name for the working copy of the fstab file... |
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-- |
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local function syspath( varname ) |
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-- |
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-- ...using this local helper function to ensure that the path name |
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-- string, returned from the environment, is free from insignificant |
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-- trailing directory name separators, and that all internal sequences |
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-- of directory name separators are normalized to a single '/'. |
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-- |
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local pathname = string.gsub( os.getenv( varname ), "[/\\]+", "/" ) |
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return string.match( pathname, "(.*[^/])/*$" ) |
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end |
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local sysroot = syspath( "MSYS_SYSROOT" ) |
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local mingw32_sysroot = syspath( "MINGW32_SYSROOT" ) |
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local fstab_file_name = sysroot .. "/etc/fstab" |
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-- |
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-- The following may be adjusted, to control the layout of the mount |
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-- point mapping records, within the fstab file. |
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-- |
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local path_name_field_width, tab_width = 40, 8 |
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-- |
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-- Define a template, from which a sample fstab file for the current |
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-- MSYS installation may be generated, on invocation of this module's |
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-- "dump_sample" method... |
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-- |
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local fstab_sample = |
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{ '# /etc/fstab.sample -- sample mount table configuration for MSYS.', |
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'', |
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'# Lines with a "#" in column one are interpreted as comment lines;', |
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'# with the exception of comments described as "magic", neither these', |
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'# lines, nor any blank lines, are interpreted as configuration.', |
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'', |
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'# Comment lines which are described as "magic" should neither be', |
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'# deleted, nor edited manually; ignoring this advice may cause your', |
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'# MSYS installation to malfunction.', |
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'', |
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'# When running MSYS from a portable device, such as a USB thumb drive,', |
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'# the following "magic" comment is used to track changes in host drive', |
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'# letter assignment, so allowing MSYS-Portable start-up hooks to remap', |
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'# mount table entries which refer to the relocated device:', |
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'#', |
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'# MSYSROOT=D:/PortableApps/MSYS/1.0', |
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'', |
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'# The mount table configuration follows below. The line format is', |
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'# simple: you specify the Win32 path, followed by one or more space or', |
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'# tab delimiters, followed by the mount point name. In a typical UNIX', |
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'# installation, each mount point must exist as a named directory on a', |
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'# physically accessible device, before it can actually be used as a', |
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'# mount point. For this implementation the "must exist" requirement', |
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'# is not enforced; however, it will assist programs such as find, and', |
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"# readline's tab completion if each does physically exist.", |
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'', |
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'# Win32_Path Mount_Point', |
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'#------------------------------------- -----------', |
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'c:/mingw /mingw' |
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} |
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-- |
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-- ...and a further template for a working configuration. |
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-- |
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local fstab_basic = |
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{ '# /etc/fstab -- mount table configuration for MSYS.', |
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'# Please refer to /etc/fstab.sample for explanatory annotation.', |
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'', |
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'# MSYS-Portable needs this "magic" comment:', |
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'# MSYSROOT=D:/PortableApps/MSYS/1.0', |
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'', |
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'# Win32_Path Mount_Point', |
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'#------------------------------------- -----------', |
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'c:/mingw /mingw' |
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} |
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-- |
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-- Define Lua regular expressions which may be used to identify |
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-- comment lines within the fstab file; (the first will match any |
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-- comment, while the second is specific to the "magic" comment, |
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-- as used by MSYS-Portable, to track changes in the allocation |
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-- of the drive identifier for the host device). |
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-- |
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local fstab_comment_line = "^#" |
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local fstab_device_magic = "^(#%s*MSYSROOT=)(%S*)" |
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-- |
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local function map_root_device( assignment ) |
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-- |
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-- A function to update the "magic" comment, which records the |
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-- allocation of the MSYS-Portable host device. |
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-- |
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return string.gsub( assignment, fstab_device_magic, "%1" .. sysroot ) |
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end |
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-- |
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-- Define a Lua regular expression which may be used to verify |
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-- that any fstab file record represents a well formed mount point |
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-- specification; it also incorporates capture fields, which may |
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-- be used to extract each of the path name and mount point |
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-- identification fields from the specification. |
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-- |
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local fstab_mount_specification = "^%s*(%S+)%s+(%S+)%s*$" |
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-- |
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local function is_mount_specification( line ) |
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-- |
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-- A function to verify any fstab file record against the |
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-- preceding regular expression, to confirm whether it does |
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-- represent a well formed mount point specification. |
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-- |
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return string.match( line, fstab_mount_specification ) |
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end |
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-- |
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local function get_mapped_path( specification ) |
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-- |
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-- A function to extract the associated path name field from |
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-- any well formed mount point specification record. |
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-- |
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return string.gsub( specification, fstab_mount_specification, "%1" ) |
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end |
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-- |
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local function get_mount_point( specification ) |
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-- |
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-- A function to extract the mount point identification field |
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-- from any well formed mount point specification record. |
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-- |
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return string.gsub( specification, fstab_mount_specification, "%2" ) |
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end |
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-- |
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-- In the event that a mount table configuration has already been |
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-- specified for this installation, capture this into an internal |
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-- "as built" configuration table... |
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-- |
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local fstab_as_built = {} |
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local fstab = io.open( fstab_file_name ) |
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if fstab |
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then |
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-- |
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-- ...reading the existing configuration file, line by line... |
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-- |
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for line in fstab:lines() |
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do |
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-- |
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-- ...identifying comment lines... |
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-- |
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if string.match( line, fstab_comment_line ) |
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then |
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-- |
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-- ...and ignoring all such, except any "device magic" line... |
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-- |
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if string.match( line, fstab_device_magic ) |
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then |
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-- |
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-- ...from which we retrieve, and subsequently update, the |
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-- configuration-specific "sysroot" identification. |
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-- |
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sysroot = string.gsub( line, fstab_device_magic, "%2" ) |
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end |
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-- |
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-- Also identify mount point specification lines... |
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-- |
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elseif is_mount_specification( line ) |
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then |
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if string.match( get_mount_point( line ), "^/mingw$" ) |
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then |
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-- |
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-- ...and preserve the user's pre-configured path assignment |
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-- for the "/mingw" mount point, if any. |
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-- |
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mingw32_sysroot = get_mapped_path( line ) |
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-- |
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else |
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-- |
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-- ...while, for all EXCEPT the "/mingw" mount point, |
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-- simply record the configuration. |
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-- |
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table.insert( fstab_as_built, line ) |
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end |
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end |
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end |
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end |
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-- |
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-- |
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local function fstab_write_configuration( fstab, template, current ) |
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-- |
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-- A function to write an fstab configuration to a designated output |
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-- stream, based on a specified template, reproducing and encapsulating |
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-- any existing configuration which may also have been specified... |
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-- |
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local function fstab_writeln( line ) |
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-- |
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-- ...using this helper function to write line by line. |
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-- |
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fstab:write( line .. "\n" ) |
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end |
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-- |
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local function assign_mount_point( mapped_path, mount_point ) |
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-- |
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-- This helper function formats each mount point specification |
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-- into a neatly tabulated layout... |
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-- |
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local filled = string.len( mapped_path ) |
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repeat |
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mapped_path, filled = mapped_path .. "\t", filled + tab_width |
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until filled >= path_name_field_width |
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-- |
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-- ...to be written out, with one line per mount point. |
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-- |
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fstab_writeln( mapped_path .. mount_point ) |
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end |
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-- |
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-- Process the template, line by line... |
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-- |
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for ref, line in next, template |
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do |
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-- ...and for each comment, or blank line encountered... |
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-- |
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if string.match( line, "^#" ) or string.match( line, "^%s*$" ) |
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then |
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-- ...simply reproduce it in the output stream, while taking |
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-- care to update any "device magic" which it may incorporate, |
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-- so that it fits the configuration of this installation. |
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-- |
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fstab_writeln( map_root_device( line ) ) |
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-- |
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-- When we encounter a mount point specification line -- for |
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-- which each of the embedded templates should include exactly |
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-- one example... |
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-- |
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elseif is_mount_specification( line ) |
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then |
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-- ...write out the specification for the "/mingw" mount |
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-- point, as appropriate for this installation. |
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-- |
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assign_mount_point( mingw32_sysroot, "/mingw" ) |
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end |
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end |
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-- |
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-- And finally... |
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-- |
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if current |
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then |
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-- ...when inclusion of the current mount configuration has been |
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-- specified, we process each configuration record in turn... |
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-- |
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for ref, line in next, current |
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do |
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-- ...and write out its corresponding mount point specification, |
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-- (noting that we have already excluded the "/mingw" mount point |
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-- from the recorded configuration, but we have already written a |
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-- specification record for it). |
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-- |
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assign_mount_point( get_mapped_path( line ), get_mount_point( line ) ) |
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end |
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end |
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end |
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-- |
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-- |
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function M.pathname( suffix ) |
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-- |
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-- An exported utility function, to facilitate identification of |
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-- the full MS-Windows path name for the "/etc/fstab" configuration |
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-- file, as appropriate to the current installation... |
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-- |
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if suffix |
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then |
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-- ...appending any suffix which may have been specified, (e.g. |
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-- to specify a reference to the "/etc/fstab.sample" file)... |
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-- |
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return fstab_file_name .. suffix |
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end |
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-- |
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-- ...otherwise, specifying a reference to "/etc/fstab" itself. |
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-- |
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return fstab_file_name |
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end |
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-- |
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-- |
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function M.dump_sample( stream_file ) |
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-- |
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-- An exported utility function, providing a method for displaying, |
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-- or otherwise emitting suitable content for the "/etc/fstab.sample" |
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-- file, as directed by the embedded "fstab_sample" template... |
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-- |
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if not stream_file |
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then |
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-- ...writing to "stdout", in the event that no other destination |
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-- has been specified. |
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-- |
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stream_file = io.stdout |
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end |
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-- |
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-- Regardless of output destination, we delegate output to this local |
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-- function, processing the integral sample file template, but we omit |
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-- the current mount table configuration. |
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-- |
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fstab_write_configuration( stream_file, fstab_sample ) |
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end |
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-- |
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-- |
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function M.initialize( stream_file ) |
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-- |
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-- The primary initialization function, exported for use by mingw-get, |
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-- to write a working mount table configuration to the specified file |
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-- stream, which, unless otherwise specified... |
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-- |
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local default_stream_file = nil |
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if not stream_file |
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then |
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-- ...is to be directed to the default "/etc/fstab" file. |
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-- |
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default_stream_file = io.open( fstab_file_name, "w" ) |
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stream_file = default_stream_file |
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end |
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-- |
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-- Once again, regardless of how the output file has been identified, |
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-- provided the stream has been successfully assigned... |
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-- |
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if stream_file |
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then |
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-- ...we delegate the actual output function to the local helper, |
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-- this time, processing the integral working file template, and we |
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-- include the record of the current mount table configuration. |
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-- |
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fstab_write_configuration( stream_file, fstab_basic, fstab_as_built ) |
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end |
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-- |
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-- Finally, when updating the default "/etc/fstab" configuration, |
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-- via a locally opened output file stream... |
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-- |
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if default_stream_file |
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then |
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-- ...we must now ensure that this output stream is closed. |
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-- |
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io.close( default_stream_file ) |
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end |
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end |
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-- |
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-- Since this source file is intended to be loaded as a Lua module, we |
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-- must ultimately return a reference handle for it. |
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-- |
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return M |
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-- |
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-- $RCSfile$: end of file */ |
