From: Jakub Jirutka <jakub@jirutka.cz>
Date: Sat, 11 Sep 2021 22:52:03 +0200
Subject: [PATCH] Hack fprint-list-udev-hwdb to generate udev rules

hwdb is systemd/udev specific, it's not widely supported. Let me quote
author of libudev-zero:

> Udev hwdb is yet another illustration of systemd-like approach. What the
> hell "userspace /dev" has to do with parsing hardware
> database(pci.ids, usb.ids) and setting/remapping buttons? Udev smells
> like systemd by trying to implement all possible functionality in the
> single daemon/code base. Standalone UNIX-way programs much better
> suited for such purposes.

This patch adds hacky support for generating classic udev rules (same as
in the older versions) into fprint-list-udev-hwdb program - if environment
variable HACK_GEN_RULES is present, it outputs udev rules instead of hwdb
entries.

See https://gitlab.freedesktop.org/libfprint/libfprint/-/issues/336

diff --git a/libfprint/fprint-list-udev-hwdb.c b/libfprint/fprint-list-udev-hwdb.c
index dadb303..d2c4ada 100644
--- a/libfprint/fprint-list-udev-hwdb.c
+++ b/libfprint/fprint-list-udev-hwdb.c
@@ -20,6 +20,7 @@
  */
 
 #include <config.h>
+#include <stdlib.h>
 
 #include "fpi-context.h"
 #include "fpi-device.h"
@@ -119,6 +120,8 @@
 
 GHashTable *printed = NULL;
 
+static int HACK_gen_rules = 0;
+
 static void
 print_driver (const FpDeviceClass *cls)
 {
@@ -161,12 +164,19 @@
             g_print ("\n# Known unsupported devices\n");
         }
 
+      if (!HACK_gen_rules) {
       g_print ("usb:v%04Xp%04X*\n",
                entry->vid, entry->pid);
+      } else {
+      g_print ("SUBSYSTEM==\"usb\", ATTRS{idVendor}==\"%04x\", ATTRS{idProduct}==\"%04x\", ATTRS{dev}==\"*\", TEST==\"power/control\", ATTR{power/control}=\"auto\"\n",
+               entry->vid, entry->pid);
+      g_print ("SUBSYSTEM==\"usb\", ATTRS{idVendor}==\"%04x\", ATTRS{idProduct}==\"%04x\", ENV{LIBFPRINT_DRIVER}=\"%s\"\n",
+               entry->vid, entry->pid, cls->full_name);
+      }
       num_printed++;
     }
 
-  if (num_printed > 0)
+  if (num_printed > 0 && !HACK_gen_rules)
     {
       g_print (" ID_AUTOSUSPEND=1\n");
       g_print (" ID_PERSIST=0\n");
@@ -190,6 +200,7 @@
   guint i;
 
   program_name = g_path_get_basename (argv[0]);
+  HACK_gen_rules = getenv ("HACK_GEN_RULES") != NULL;
 
   g_print ("# SPDX-License-Identifier: LGPL-2.1-or-later\n");
   g_print ("# This file has been generated using %s with all drivers enabled\n",