add from-kernel.sh

Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Author: BennoLossin

from-kernel.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+
+set -e
+
+krepo="$1"
+urepo=$(git rev-parse --show-toplevel)
+patches=$(mktemp -d)
+commit="$2"
+
+if [ ! -d "$krepo" ]; then
+    echo "expected the kernel directory as \$1, but got \"$krepo\" which either doesn't exist or is not a directory"
+    exit 1
+fi
+
+pushd "$krepo" > /dev/null
+
+if ! git cat-file -e "$commit^{commit}"; then
+    echo "commit $commit does not seem to exist."
+    exit 1
+fi
+
+echo "Copying all commits in \"$krepo\" into \"$urepo\" from commit $commit onwards:"
+git log --oneline "$commit..HEAD"
+read -p "Does this look good to you? [Y/n] " ans
+case "$ans" in
+    Y)
+        ;;
+    y)
+        ;;
+    *)
+        exit 1
+        ;;
+esac
+
+popd > /dev/null # $krepo
+
+krepo=$(realpath "$krepo")
+urepo=$(realpath "$urepo")
+patches=$(realpath "$patches")
+
+pushd "$krepo" > /dev/null
+
+git format-patch --quiet --output-directory "$patches" "$commit"
+
+pushd "$patches" > /dev/null
+
+sed -i 's/^\(Subject: \[PATCH .*\] \)rust: pin-init: /\1/' *
+
+popd > /dev/null # $patches
+
+popd > /dev/null # $krepo
+
+pushd "$urepo" > /dev/null
+
+head=$(git rev-parse HEAD)
+
+git am                                              \
+    --signoff                                       \
+    --reject                                        \
+    --interactive                                   \
+    -p3                                             \
+    --empty=drop                                    \
+    $patches/*
+
+# need the `--exec 'true'` in order for the `--no-keep-empty` option to actually do stuff
+git rebase --no-keep-empty --quiet --exec 'true' "$head"
+
+popd > /dev/null # $urepo
+
+rm $patches/*