grubeditor.sh

Automates the opening of grub{test}.cfg files in a libreboot ROM image.

1 files changed, 396 insertions, 0 deletions

diff --git a/resources/scripts/misc/grubeditor.sh b/resources/scripts/misc/grubeditor.sh
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+#!/bin/bash
+#
+# grubeditor.sh -- conveniently edit grub{test}.cfg files by automating their
+# extraction with cbfstool and the user's editor of choice.
+#
+#  Copyright (C) 2017 Zyliwax <zyliwax@protonmail.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# Usage:
+# ./grubeditor.sh [options] romimage
+#
+# Supported options:
+#
+# -h | --help: show usage help
+#
+# -r | --realcfg: generate grub.cfg instead of grubtest.cfg
+#
+# -i | --inplace: do not create a .modified romfile, instead modify the
+# existing file
+#
+# -e | --editor /path/to/editor: open the cfg file with /path/to/editor instead
+# of $EDITOR
+#
+# -s | --swapcfg: swap grub.cfg and grubtest.cfg, incompatible with other
+# options besides -i
+#
+# -x | --extractcfg: extract either grub.cfg or grubtest.cfg depending on
+# whether -r is set
+#
+# -d | --diffcfg: diff grub.cfg and grubtest.cfg, incompatible with other
+# options besides -D
+#
+# -D | --differ [/path/to/]differ: use /path/to/differ instead of "diff", can
+# be an interactive program like vimdiff
+
+# Define the list of available option in both short and long form.
+shortopts="hrie:sdD:"
+longopts="help,realcfg,inplace,editor:,swapcfgs,diffcfgs,differ:"
+
+# Variables for modifying the program's operation
+edit_realcfg=0
+edit_inplace=0
+do_swapcfgs=0
+do_diffcfgs=0
+# Path to cbfstool, filled by detect_architecture
+# (Possible to provide explicitly and disclaim warranty?)
+cbfstool=""
+# Editor variables
+use_editor=""
+default_editor="vi"
+editor_rawarg=""
+# Differ variables
+use_differ=""
+default_differ="diff"
+differ_rawarg=""
+# Last but not least, the rom file itself
+romfile=""
+
+# This program works primarily from a cascade of functions. Let's define them.
+
+get_options() {
+    # Test for enhanced getopt.
+    getopt --test > /dev/null
+    if [[ $? -ne 4 ]]; then
+        echo "Your environment lacks enhanced getopt, so you cannot run this script properly."
+        exit 205
+    fi
+
+    # Parse the command line options based on the previously defined values. 
+    parsedopts=$(getopt --options ${shortopts} --longoptions ${longopts} --name "${0}" -- "$@")
+    if [[ $? -ne 0 ]]; then # getopt didn't approve of your arguments
+        echo "Unrecognized options."
+        exit 206
+    fi
+
+    # Use eval set to properly quote the arguments
+    eval set -- "$parsedopts"
+
+    # Interpret the arguments one-by-one until you run out.
+    while [[ 1 ]]; do
+        case "$1" in
+            -h|--help)
+                show_help
+                # I return non-zero here just so nobody thinks we successfully edited grub.cfg
+                exit 200
+                ;;
+            -r|--realcfg)
+                edit_realcfg=1
+                shift
+                ;;
+            -i|--inplace)
+                edit_inplace=1
+                shift
+                ;;
+            -e|--editor)
+                editor_rawarg="$2" 
+                shift 2
+                ;;
+            -s|--swapcfgs)
+                do_swapcfgs=1
+                shift
+                ;;
+            -d|--diffcfgs)
+                do_diffcfgs=1
+                shift
+                ;;
+            -D|--differ)
+                differ_rawarg="$2" 
+                shift 2
+                ;;
+            --)
+                # Stop interpreting arguments magically.
+                shift
+                break
+                ;;
+            *)
+                echo "Something went wrong while interpreting the arguments!"
+                echo "I hit \"${1}\" and don't know what to do with it."
+                exit 209
+                ;;
+        esac
+    done
+    
+    # The only option remaining should be the input file. Ensure it was
+    # provided before proceeding with the rest of the script and capture it if
+    # it was.
+    if [[ $# -ne 1 ]]; then
+        echo "You have specified multiple (or no) input files, which is unsupported."
+        echo "Please rerun this command with just a single filename to remove any chance for ambiguity."
+        exit 210
+    fi
+    romfile="$1"
+}
+
+determine_architecture() {
+    # The cbfstool in _util is packed only for i686, x86_64, and armv7l. This
+    # procedure is necessary for this process to not fail. After this process
+    # is over, the variable $cbfstool gets filled with the appropriate value
+    # for use by the rest of the script.
+    arch="$(uname -m)"
+    case "${arch}" in
+        armv7l|i686|x86_64)
+            echo "Supported architecture \"${arch}\" detected. You may proceed."
+            cbfstool="./cbfstool/${arch}/cbfstool"
+            ;;
+        *) 
+            echo "Unsupported architecture \"${arch}\" detected! You may not proceed."
+            exit 230
+            ;;
+    esac
+}
+
+determine_operation() {
+    if [[ $do_swapcfgs -eq 1 ]]; then
+        swap_configs
+        exit $?
+    elif [[ $do_diffcfgs -eq 1 ]]; then
+        diff_configs
+        exit $?
+    else
+        edit_config
+        exit $?
+    fi
+}
+
+# These functions are not part of the primary function cascade but are
+# referenced within them either directly or indirectly from other helper
+# functions depending on the operations requested by the user.
+
+show_help() {
+    cat << HELPSCREEN
+${0} -- conveniently edit grub{test}.cfg files in Libreboot ROM image files by
+automating their extraction with cbfstool and the user's editor of choice.
+
+-h | --help: show usage help
+
+-r | --realcfg: generate grub.cfg instead of grubtest.cfg
+
+-i | --inplace: do not create a .modified romfile, instead modify the
+existing file
+
+-e | --editor [/path/to/]editor: open the cfg file with /path/to/editor instead
+of the value of \$EDITOR
+
+-s | --swapcfg: swap grub.cfg and grubtest.cfg
+
+-d | --diffcfg: diff grub.cfg and grubtest.cfg
+
+-D | --differ [/path/to/]differ: use /path/to/differ instead of "diff", can be
+an interactive program like vimdiff
+HELPSCREEN
+}
+
+swap_configs() {
+    # Procedure:
+    # 1. Call cbfstool twice, once each to extract grub.cfg and grubtest.cfg.
+    # 2. If --inplace not specified, copy ${romfile} to ${romfile}.modified and
+    # implement remaining steps on this copy. Otherwise, implement remaining
+    # steps on ${romfile}.
+    # 3. Call cbfstool twice, once each to delete grub.cfg and grubtest.cfg
+    # from romfile.
+    # 4. Call cbfstool twice, once to embed grubtest.cfg as grub.cfg into
+    # romfile and again to embed grub.cfg as grubtest.cfg into romfile.
+    # 5. Delete the extracted grub.cfg and grubtest.cfg files.
+    # 6. You're done!
+
+    # Extract config files from provided romfile.
+    ${cbfstool} ${romfile} extract -n grub.cfg -f /tmp/real2test.cfg
+    ${cbfstool} ${romfile} extract -n grubtest.cfg -f /tmp/test2real.cfg
+
+    # Determine whether to edit inplace or make a copy.
+    if [[ $edit_inplace -eq 1 ]]; then
+        outfile="${romfile}"
+    else
+        cp "${romfile}" "${romfile}.modified"
+        outfile="${romfile}.modified"
+    fi
+
+    # Remove config files from the output file.
+    ${cbfstool} ${outfile} remove -n grub.cfg
+    ${cbfstool} ${outfile} remove -n grubtest.cfg
+
+    # Embed new configs into the output file.
+    ${cbfstool} ${outfile} add -t raw -n grub.cfg -f /tmp/test2real.cfg
+    ${cbfstool} ${outfile} add -t raw -n grubtest.cfg -f /tmp/real2test.cfg
+    
+    # Delete the tempfiles.
+    rm /tmp/test2real.cfg /tmp/real2test.cfg
+}
+
+diff_configs() {
+    # Procedure:
+    # 1. Call cbfstool twice, once to extract grub.cfg and grubtest.cfg.
+    # 2. Execute ${use_differ} grub.cfg grubtest.cfg #.
+    # 3. Delete the extracted grub.cfg and grubtest.cfg files.
+    # 4. You're done!
+
+    # Determine the differ command to use.
+    find_differ
+
+    # Extract config files from provided romfile.
+    ${cbfstool} ${romfile} extract -n grub.cfg -f /tmp/grub_tmpdiff.cfg
+    ${cbfstool} ${romfile} extract -n grubtest.cfg -f /tmp/grubtest_tmpdiff.cfg
+
+    # Run the differ command with real as first option, test as second option.
+    ${use_differ} /tmp/grub_tmpdiff.cfg /tmp/grubtest_tmpdiff.cfg
+}
+
+edit_config() {
+    # Procedure:
+    # 1. If --realcfg specified, set ${thisconfig} to "grub.cfg". Otherwise,
+    # set ${thisconfig} to "grubtest.cfg".
+    # 2. Call cbfstool once to extract ${thisconfig} from ${romfile}.
+    # 3. Run ${use_editor} ${thisconfig}.
+    # 4. If ${use_editor} returns zero, proceed with update procedure:
+    # 5. Call cbfstool once to extract ${thisconfig} from ${romfile}.
+    # 6. Quietly diff the extracted file with the edited file. If diff returns
+    # zero, take no action: warn the user that the files were the same, delete
+    # both files, then skip the remaining steps (you're done)! Otherwise, the
+    # files are different and you must continue with the update procedure.
+    # 7. If --inplace not specified, copy ${romfile} to ${romfile}.modified and
+    # implement remaining steps on this copy. Otherwise, implement remaining
+    # steps on ${romfile}.
+    # 8. Call cbfstool once to delete internal pre-update ${thisconfig} from
+    # the rom file.
+    # 9. Call cbfstool once to embed the updated ${thisconfig} that was just
+    # edited into the rom file.
+    # 10. Alert the user of success (either explicitly or by not saying
+    # anything, either way return zero).
+    # 11. You're done!
+
+    # Determine the editor command to use.
+    find_editor
+
+    # Determine whether we are editing the real config or the test config.
+    if [[ $edit_realcfg -eq 1 ]]; then
+        thisconfig="grub.cfg"
+    else
+        thisconfig="grubtest.cfg"
+    fi
+
+    # Extract the desired configuration file from the romfile.
+    tmp_editme="/tmp/${thisconfig%.cfg}_editme.cfg"
+    ${cbfstool} ${romfile} extract -n ${thisconfig} -f ${tmp_editme}
+
+    # Launch the editor!
+    ${use_editor} ${tmp_editme}
+
+    # Did the user commit the edit?
+    if [[ $? -eq 0 ]]; then
+        # See if it actually changed from what exists in the cbfs.
+        tmp_refcfg="/tmp/${thisconfig%.cfg}_ref.cfg"
+        ${cbfstool} ${romfile} extract -n ${thisconfig} -f ${tmp_refcfg}
+        # Diff the files as quietly as possible.
+        diff -q ${tmp_editme} ${tmp_refcfg} &> /dev/null
+        if [[ $? -ne 0 ]]; then
+            # The files differ, so it won't be frivolous to update the config.
+            # See if the user wants to edit the file in place.
+            # (This code should really be genericized and placed in a function
+            # to avoid repetition.)
+            if [[ $edit_inplace -eq 1 ]]; then
+                outfile="${romfile}"
+            else
+                cp "${romfile}" "${romfile}.modified"
+                outfile="${romfile}.modified"
+            fi
+            # Remove the old config, add in the new one.
+            ${cbfstool} ${outfile} remove -n ${thisconfig}
+            ${cbfstool} ${outfile} add -t raw -n ${thisconfig} -f ${tmp_editme}
+        else
+            echo "No changes to config file. Not updating the ROM image."
+        fi
+        # We are done with the config files. Delete them.
+        rm ${tmp_editme}
+        rm ${tmp_refcfg}
+    fi
+}
+
+find_differ() {
+    found_differ=0
+
+    if [[ -n "${differ_rawarg}" ]]; then
+        which "${differ_rawarg}" &> /dev/null
+        if [[ $? -eq 0 ]]; then
+            echo "Using differ \"${differ_rawarg}\"..."
+            use_differ="${differ_rawarg}"
+            found_differ=1
+        else
+            echo "The provided \"${differ_rawarg}\" is not a valid command!"
+            echo "Defaulting to ${default_differ}..."
+            use_differ="${default_differ}"
+        fi
+    fi
+    
+    if [[ $found_differ -eq 1 ]]; then 
+        return
+    else
+        echo "Defaulting to ${default_differ}..."
+        use_differ="${default_differ}"
+    fi
+}
+
+find_editor() {
+    found_editor=0
+
+    if [[ -n "${editor_rawarg}" ]]; then
+        which "${editor_rawarg}" &> /dev/null
+        if [[ $? -eq 0 ]]; then
+            echo "Using editor \"${editor_rawarg}\"..."
+            use_editor="${editor_rawarg}"
+            found_editor=1
+        else
+            echo "The provided \"${editor_rawarg}\" is not a valid command!"
+            echo "Defaulting to ${default_editor}..."
+            use_editor="${default_editor}"
+        fi
+    fi
+    
+    if [[ $found_editor -eq 1 ]]; then 
+        return
+    else
+        if [[ -n "${EDITOR}" ]]; then
+            which "${EDITOR}" &> /dev/null
+            if [[ $? -ne 0 ]]; then
+                echo "Your \$EDITOR is defined as ${EDITOR}, but is not a valid command!"
+                echo "(This is bad. I highly suggest fixing this in your ~/.bashrc.)"
+                echo "Defaulting to ${default_editor}..."
+                use_editor="${default_editor}"
+            else
+                echo "Using your defined \$EDITOR \"$EDITOR\"..."
+                use_editor="${EDITOR}"
+            fi
+        else
+            echo "\$EDITOR blank, defaulting to ${default_editor}..."
+            use_editor="${default_editor}"
+        fi
+    fi
+}
+
+# Run through the primary function cascade.
+get_options $@
+determine_architecture
+determine_operation