From be2df26e3895a241a6c9d0f0ef4864b805e2cf2f Mon Sep 17 00:00:00 2001
From: illiliti <illiliti@protonmail.com>
Date: Wed, 15 Jul 2020 23:26:12 +0300
Subject: [PATCH] implement /proc hotplugger

---
 README.md |  2 +-
 config    |  5 ++++-
 init      | 14 +++++++++++++-
 tinyramfs |  5 ++---
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index c17f62c..2a60bef 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ Dependencies
   - Optional
 * `blkid`
   - Required for UUID, LABEL, PARTUUID support
-* `mdev` OR `mdevd` OR `eudev` OR `systemd-udevd`
+* `mdev` OR `mdevd` OR `eudev` OR `systemd-udevd` OR CONFIG_UEVENT_HELPER
   - systemd-udevd not tested
 * `lvm2`
   - Required for LVM support
diff --git a/config b/config
index 7cfef6a..160651c 100644
--- a/config
+++ b/config
@@ -46,7 +46,10 @@
 #root_opts=""
 
 # device manager
-# supported - udev, mdev, mdevd
+#
+# supported - none, proc, udev, mdev, mdevd
+# none means no device manager. requires monolithic kernel and you will unable to use UUID, LABEL, PARTUUID, /dev/mapper/*
+# proc requires monolithic kernel and legacy CONFIG_UEVENT_HELPER
 #
 #devmgr=""
 
diff --git a/init b/init
index 7d29a15..10173b7 100755
--- a/init
+++ b/init
@@ -91,6 +91,16 @@ setup_devmgr()
     [ "$break" = devmgr ] && { print "break before setup_devmgr()"; sh; }
 
     case "$devmgr" in
+        proc)
+            command -v device-helper > /proc/sys/kernel/hotplug
+
+            # get ready for fork bomb. kek
+            find /sys/devices -name uevent |
+
+            while read -r uevent; do
+                printf add > "$uevent"
+            done
+        ;;
         udev)
             udevd -N never & devmgr_pid="$!"
             udevadm trigger -c add -t subsystems
@@ -133,7 +143,9 @@ boot_system()
 {
     [ "$break" = boot ] && { print "break before boot_system()"; sh; }
 
-    kill "$devmgr_pid"
+    {
+        kill "$devmgr_pid" || printf '\n' > /proc/sys/kernel/hotplug
+    } 2> /dev/null || :
 
     # temporary workaround until util-linux release a new version
     # see https://github.com/karelzak/util-linux/issues/997
diff --git a/tinyramfs b/tinyramfs
index 32beccc..c19f1de 100755
--- a/tinyramfs
+++ b/tinyramfs
@@ -364,9 +364,8 @@ copy_devmgr()
     # false positive
     # shellcheck disable=2016
     case "$devmgr" in
-        none)
-            # TODO implement mode without device manager using deprecated
-            # /sys/kernel/uevent_helper or /proc/sys/kernel/hotplug
+        proc)
+            copy_binary find
         ;;
         mdev)
             for _binary in mdev find; do