add basic module support

7 files changed, 16 insertions, 5 deletions

diff --git a/.gitignore b/.gitignore
index 7226a25..b50d433 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 /gen_init_cpio
 /initramfs.d
 /initramfs.img
+/modules.sh
diff --git a/Makefile b/Makefile
index e408200..f36ca69 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 all: initramfs.img
 
-initramfs.img: gen_init_cpio dropbear_ed25519_host_key
+initramfs.img: gen_init_cpio dropbear_ed25519_host_key modules.sh
 	./make
 
 gen_init_cpio: gen_init_cpio.c
@@ -9,6 +9,10 @@ gen_init_cpio: gen_init_cpio.c
 dropbear_ed25519_host_key:
 	dropbearkey -t ed25519 -f $@
 
+modules.sh: modules
+	printf '%s\n' '#!/bin/sh' 'set -e' > $@
+	xargs -a $< -L1 -r modprobe --show-depends >> $@
+
 install: initramfs.img
 	rm -f /boot/initramfs.img.old /boot/initramfs.img.new
 	cp initramfs.img /boot/initramfs.img.new || rm -f /boot/initramfs.img.new
diff --git a/README b/README
index ddbb939..2f5b3e7 100644
--- a/README
+++ b/README
@@ -13,6 +13,7 @@ Features:
 - firmware loading (trivial, done by kernel)
 - extremely fast initramfs creation: compression off: ~70ms cold cache, ~30ms
   warm; lz4 --best: 1.6s
+- udev/mdev-free module loading
 - no temporary files during creation
 - extremely fast initramfs runtime: ~zero overhead compared to direct kernel
   loading
@@ -23,10 +24,6 @@ Drawbacks:
 
 - uses existing system tools
 - pure POSIX shell + POSIX Makefile
-- no modprobe support, custom kernel is required to use myinitramfs in useful
-  cases. if you want dynamic module loading (if you want modprobe, then you
-  probably also want mdev or udev), probably better to use mkinitcpio or
-  dracut.
 
 Usage:
 
diff --git a/cpio_list.txt b/cpio_list.txt
index ed02ceb..f0c7b7c 100644
--- a/cpio_list.txt
+++ b/cpio_list.txt
@@ -20,6 +20,7 @@ slink /etc/mtab /proc/self/mounts 0755 0 0
 
 # executables
 file /bin/busybox /bin/busybox 0755 0 0
+file /etc/modules.sh ./modules.sh 0755 0 0
 file /init ./init 0755 0 0
 
 # firmware
diff --git a/init b/init
index 7a63521..706de93 100644
--- a/init
+++ b/init
@@ -11,6 +11,8 @@ mkdir -p /dev/pts
 # /dev/pts for dropbear
 mount -t devpts devpts /dev/pts
 
+/etc/modules.sh || exit
+
 (
 ip link set eth0 up
 udhcpc -i eth0
diff --git a/make b/make
index 5dc25f1..9ce479c 100755
--- a/make
+++ b/make
@@ -32,6 +32,11 @@ gen_cmd() {
 # generate the main file list
 gen_cpio_list() {
     sed -e '/^#/d' cpio_list.txt
+    while read insmod mod args; do
+        if [ "$insmod" = insmod ]; then
+            printf 'file %s %s 0644 0 0\n' "$mod" "$mod"
+        fi
+    done < modules.sh
     gen_cmd e2fsck
     gen_cmd dropbear
     # cryptsetup argon2 uses pthread_cancel, glibc dlopens libgcc_s.so.1
diff --git a/modules b/modules
new file mode 100644
index 0000000..1506af7
--- /dev/null
+++ b/modules
@@ -0,0 +1 @@
+vfat