add helper for age

dotfiles/commonfunc

@@ -8,6 +8,156 @@
 # {{@@ header() @@}}
 #
 
+# age encryption / decryption helpers
+# based on https://git.sr.ht/~digital/secretFiles
+if [[ $(command -v age) ]]; then
+  # get recipients for age file to encrypt with
+  ageGetRecipientsList() {
+    local target="${1}"
+    local search="${target}"
+    local recipients=( "-R" "secrets/hostkeys/masterkey.pubkey" )
+    local recip
+    while true; do
+      if test -d "${search}.recipients"; then
+        for recip in $(ls ${search}.recipients) ; do
+          if test -n "${recip}"; then
+            recipients+=("-R" "${search}.recipients/${recip}")
+          fi
+        done
+      elif test -f "${search}.recipients"; then
+        recipients+=( "-R" "${search}.recipients")
+      fi
+      if test "$(realpath ${search})" = "$(realpath $(pwd))"; then
+        break
+      fi
+      search=$(dirname "${search}")
+    done
+    echo "${recipients[@]}"
+  }
+
+  age-gen-key() {
+    set -efu -o pipefail
+
+    local keyname="${1}"
+
+    mkdir -p "secrets/hostkeys/"
+    echo "generating new keys for host ${keyname}";
+    age-keygen \
+      2> "secrets/hostkeys/${keyname}.pubkey" \
+      | age -p --armor -e -o "secrets/hostkeys/${keyname}.privkey"
+    sed -i 's/Public key: //' "secrets/hostkeys/${keyname}.pubkey"
+
+    set +efu +o pipefail
+  }
+
+  age-import-secret() {
+    set -euf -o pipefail
+
+    local secret_path="${1}"
+    local recipients_list=$(ageGetRecipientsList "${secret_path}")
+    local dirname="$(dirname ${secret_path})"
+    local identity="${MASTERKEY_FILE:-secrets/hostkeys/masterkey.privkey}"
+
+    mkdir -p "${dirname}"
+
+    age ${recipients_list[@]} --encrypt --armor --output "${secret_path}"
+
+    set +efu +o pipefail
+  }
+
+  age-edit-file() {
+    set -euf -o pipefail
+    local current_umask=$(umask)
+    umask 177
+
+    local secret_path="${1}"
+    local tmp_path="$(mktemp -p /dev/shm)"
+    local recipients_list=$(ageGetRecipientsList "${secret_path}")
+    local identity="${MASTERKEY_FILE:-$([[ -f "$(realpath "secrets/hostkeys/masterkey.privkey")" ]] && echo -n "$(realpath "secrets/hostkeys/masterkey.privkey")" || echo -n "/dev/stdin")}"
+    # [[ -f "$(realpath "secrets/hostkeys/masterkey.privkey")" ]] && local identity="$(realpath "secrets/hostkeys/masterkey.privkey")" || 
+
+    if test -e "${secret_path}"; then
+      set +e +o pipefail
+
+      age \
+        --decrypt \
+        --identity "${identity}" \
+        --output "${tmp_path}" \
+        "${secret_path}" || local decrypt_failed=true
+      
+      set -e -o pipefail
+    else
+      # if file descriptor 0 is not a terminal, ie if /dev/stdin is a pipe
+      if [ ! -t 0 ]; then
+        cat "${identity}" > /dev/null
+      fi
+    fi
+
+    if [[ ! ${decrypt_failed:-} ]]; then
+      local mod_time_before=$(stat --format "%Y" "${tmp_path}")
+      ${EDITOR} "${tmp_path}"
+      local mod_time_after=$(stat --format "%Y" "${tmp_path}")
+
+      if test "${mod_time_before}" != "${mod_time_after}"; then
+        echo "change detected, reencrypting file" > /dev/stderr
+        age ${recipients_list[@]} --encrypt --armor --output "${secret_path}" "${tmp_path}"
+      else
+        echo "no change detected, not reencrypting file" > /dev/stderr
+      fi
+    fi
+
+    rm "${tmp_path}"
+
+    umask ${current_umask}
+    set +efu +o pipefail
+  }
+
+  age-reencrypt-all() {
+    set -euf -o pipefail
+    local current_umask=$(umask)
+    umask 177
+
+    local identity="${1:-/dev/stdin}"
+    local identity_file="$(mktemp -u -p /dev/shm)"
+
+    # make the identity file reuseable, in case it actually is /dev/stdin
+    umask 177
+    cat "${identity}" > "${identity_file}"
+
+    find "secrets" -type f -not -name "*\.recipients" \
+        | grep -v "^secrets/hostkeys/"| while read line; do
+        if ! grep -q "^-----BEGIN AGE ENCRYPTED FILE-----$" "${line}"; then
+            echo "skipping unecrypted file '${line}'"
+            continue
+        fi
+        local recipients=$(ageGetRecipientsList "${line}")
+        echo "reencrypting '${line}' for recipients ${recipients[@]}"
+        local content="$(age --decrypt \
+            --identity "${identity_file}" \
+            "${line}" \
+        )" || {
+            echo "ERROR: failed decryption of '${line}'" > /dev/stderr
+            echo "aborting and leaving secrets store in an inconsistent state" > /dev/stderr
+            exit 2
+        }
+        if test $? -eq 0 ; then
+            echo -n "${content}" \
+                | age ${recipients[@]} \
+                --encrypt \
+                --armor \
+                --output "${line}"
+        fi
+    done
+
+    rm "${identity_file}"
+
+    umask ${current_umask}
+    set +efu +o pipefail
+
+    echo "SUCCESS" > /dev/stderr
+  }
+fi
+
 # eza - set aliasses for eza to use it as ls replacement
 if [[ $(command -v eza) ]]; then
   ezafunc() {