Make usergen a bit more useful

So far, usergen printed a JSON object over standard output that had to
be manually copied into db.json. Now, this step is done automatically,
thanks to jq(1). OTOH, user directory is now also created by usergen.

2 files changed, 40 insertions, 7 deletions

diff --git a/README.md b/README.md
index 241dd8b..255453c 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,7 @@ to `slcl`. If required, encryption should be done before uploading e.g.: using
 - [`dynstr`](https://gitea.privatedns.org/xavi92/dynstr)
 (provided as a `git` submodule).
 - `xxd` (for [`usergen`](usergen) only).
+- `jq` (for [`usergen`](usergen) only).
 - CMake (optional).
 
 ### Ubuntu / Debian
diff --git a/usergen b/usergen
index ec63fd3..42c18fe 100755
--- a/usergen
+++ b/usergen
@@ -2,8 +2,29 @@
 
 set -e
 
+usage()
+{
+    echo "$0 <dir>"
+}
+
+if [ $# != 1 ]; then
+    usage >&2
+    exit 1
+fi
+
+DIR=$1
+
 echo Username: >&2
 read -r USER
+
+DB="$DIR/db.json"
+
+if jq '.users[].name' "$DB" | grep -q $USER
+then
+    echo User $USER already in $DB >&2
+    exit 1
+fi
+
 echo Password: >&2
 read -r PWD
 echo "Quota, in MiB (leave empty for unlimited quota):" >&2
@@ -23,12 +44,23 @@ do
 done
 
 echo >&2
-cat <<-EOF
+TMP=$(mktemp)
+
+cleanup()
 {
-    "name": "$USER",
-    "password": "$PWD",
-    "salt": "$SALT",
-    "key": "$KEY",
-    "quota": "$QUOTA"
+    rm -f $TMP
 }
-EOF
+
+trap cleanup EXIT
+
+jq ".users += [
+{
+    \"name\": \"$USER\",
+    \"password\": \"$PWD\",
+    \"salt\": \"$SALT\",
+    \"key\": \"$KEY\",
+    \"quota\": \"$QUOTA\"
+}]" "$DB" > $TMP
+
+mv $TMP "$DB"
+mkdir "$DIR/user/$USER"