improve secrets prompting

lib/nixos.nix

@@ -260,7 +260,7 @@ in rec {
             generic-arg-help "${ownPath}" "$functionDoc" ${esc description} ${esc notesAndExamples} ${esc usageLine} || exit
         ) ; \exit 0 ; fi
 
-        # generic-arg-verify || \exit 3
+        generic-arg-verify || \exit 3
 
         # either call »argv[0]« with the remaining parameters as arguments, or if »$1« is »-c« eval »$2«.
         if [[ ''${args[trace]:-} ]] ; then set -x ; fi

lib/setup-scripts/keys.sh

@@ -7,7 +7,10 @@ function prompt-for-user-passwords { # (void)
         userPasswords[$user]=@{config.users.users!catAttrSets.password[$user]}
     done
     local user ; for user in "@{!config.users.users!catAttrSets.passwordFile[@]}" ; do
-        if ! userPasswords[$user]=$(prompt-new-password "for the user account »$user«") ; then true ; \return 1 ; fi
+        for attempt in 2 3 x ; do
+            if userPasswords[$user]=$(prompt-new-password "for the user account »$user«") ; then break ; fi
+            if [[ $attempt == x ]] ; then \return 1 ; fi ; echo "Retrying ($attempt/3):"
+        done
     done
 }
 

lib/setup-scripts/utils.sh

@@ -87,11 +87,29 @@ function write-secret {( set -u # 1: path, 2?: owner[:[group]], 3?: mode
 ## Interactively prompts for a password to be entered and confirmed.
 function prompt-new-password {( set -u # 1: usage
     read -s -p "Please enter the new password $1: "     password1 || exit ; echo 1>&2
+    if (( ${#password1} == 0 )) ; then printf 'Password empty.\n' 1>&2 ; \exit 1 ; fi
     read -s -p "Please enter the same password again: " password2 || exit ; echo 1>&2
-    if (( ${#password1} == 0 )) || [[ "$password1" != "$password2" ]] ; then printf 'Passwords empty or mismatch, aborting.\n' 1>&2 ; \exit 1 ; fi
+    if [[ "$password1" != "$password2" ]] ; then printf 'Passwords mismatch.\n' 1>&2 ; \exit 1 ; fi
     printf %s "$password1" || exit
 )}
 
+## If »secretFile« does not exist, interactively prompts up to three times for the secret to be stored in that file.
+function prompt-secret-as {( set -u # 1: what, 2: secretFile, 3?: owner[:[group]], 4?: mode
+    if [[ -e $2 ]] ; then \return ; fi
+    what=$1 ; shift
+    function prompt {
+        read -s -p "Please enter $what: " value || exit ; echo 1>&2
+        if (( ${#value} == 0 )) ; then printf 'Nothing entered. ' 1>&2 ; \return 1 ; fi
+        read -s -p "Please enter that again, or return empty to skip the check: " check || exit ; echo 1>&2
+        if [[ $check && $value != "$check" ]] ; then printf 'Entered values mismatch. ' 1>&2 ; \return 1 ; fi
+    }
+    for attempt in 2 3 x ; do
+        if prompt && printf %s "$value" | write-secret "$@" ; then break ; fi
+        if [[ $attempt == x ]] ; then echo "Aborting." 1>&2 ; \return 1 ; fi
+        echo "Retrying ($attempt/3):" 1>&2
+    done
+)}
+
 declare-flag install-system inspectScripts "" "When running installation hooks (»...*Commands« composed as Nix strings) print out and pause before each command. This works ... semi-well."
 
 ## Runs an installer hook script, optionally stepping through the script.

lib/setup-scripts/zfs.sh

@@ -56,7 +56,7 @@ function ensure-datasets {
     local zfs=@{native.zfs}/bin/zfs
 
     local name ; while IFS= read -u3 -r -d $'\0' name ; do
-        if  [[ ! $name =~ $filterExp ]] ; then printf 'Skipping dataset »%s« since it does not match »%s«\n' "$name" "$filterExp" >&2 ; continue ; fi
+        if  [[ ! $name =~ $filterExp ]] ; then : "Skipping dataset »$name« since it does not match »$filterExp«" ; continue ; fi
 
         eval 'local -A dataset='"@{config.setup.zfs.datasets[$name]}"
         eval 'local -A props='"${dataset[props]}"
@@ -118,9 +118,9 @@ function ensure-datasets {
                 ( PATH=@{native.zfs}/bin ; ${_set_x:-:} ; zfs create "${zfsCreate[@]}" "${dataset[name]}" ) || exit
             fi
             if [[ ${props[canmount]} != off ]] ; then (
-                tmpMnt=$(mktemp -d) ; trap "" EXIT && @{native.util-linux}/bin/mount -t zfs -o zfsutil "${dataset[name]}" $tmpMnt &&
-                trap "@{native.util-linux}/bin/umount '${dataset[name]}' ; rmdir $tmpMnt" EXIT &&
-                chmod 000 -- "$tmpMnt" && chown "${dataset[uid]}:${dataset[gid]}" -- "$tmpMnt" && chmod "${dataset[mode]}" -- "$tmpMnt"
+                tmp=$( mktemp -d ) && mkdir $tmp/mnt && @{native.util-linux}/bin/mount -t zfs -o zfsutil "${dataset[name]}" $tmp/mnt || exit
+                trap "@{native.util-linux}/bin/umount '${dataset[name]}' ; rmdir $tmp{/mnt,}" EXIT || exit
+                chmod 000 -- $tmp/mnt && ( cd $tmp ; chown "${dataset[uid]}:${dataset[gid]}" -- mnt && chmod "${dataset[mode]}" -- mnt ) || exit
             ) || exit ; fi
             if [[ $explicitKeylocation && $explicitKeylocation != "${props[keylocation]:-}" ]] ; then
                 ( PATH=@{native.zfs}/bin ; ${_set_x:-:} ; zfs set keylocation="$explicitKeylocation" "${dataset[name]}" ) || exit