Fail if dracut cant install required binaries (#382)

dracut/28immucore/module-setup.sh

@@ -1,31 +1,43 @@
 #!/bin/bash
 
-# called by dracut
+# check() is called by dracut to evaluate the inclusion of a dracut module in the initramfs.
+# we always want to have this module so we return 0
 check() {
     return 0
 }
 
-# called by dracut 
+# The function depends() should echo all other dracut module names the module depends on
 depends() {
     echo rootfs-block dm fs-lib lvm
     return 0
 }
 
-# called by dracut
+# In installkernel() all kernel related files should be installed
 installkernel() {
     instmods overlay
 }
 
-# called by dracut
+# custom function to check if binaries exist before calling inst_multiple
+inst_check_multiple() {
+    for bin in "$@"; do
+        if ! command -v "$bin" >/dev/null 2>&1; then
+            derror "Required binary $bin not found!"
+            exit 1
+        fi
+    done
+    inst_multiple "$@"
+}
+
+
+# The install() function is called to install everything non-kernel related.
 install() {
     declare moddir=${moddir}
     declare systemdutildir=${systemdutildir}
     declare systemdsystemunitdir=${systemdsystemunitdir}
 
-    inst_multiple immucore
+    inst_check_multiple immucore kairos-agent
-    inst_multiple kairos-agent
     # add utils used by yip stages
-    inst_multiple partprobe sync udevadm parted mkfs.ext2 mkfs.ext3 mkfs.ext4 mkfs.vfat mkfs.fat blkid lsblk e2fsck resize2fs mount umount sgdisk rsync cryptsetup growpart sfdisk gawk awk
+    inst_check_multiple partprobe sync udevadm parted mkfs.ext2 mkfs.ext3 mkfs.ext4 mkfs.vfat mkfs.fat blkid lsblk e2fsck resize2fs mount umount sgdisk rsync cryptsetup growpart sfdisk gawk awk
 
     # Install libraries needed by gawk
     inst_libdir_file "libsigsegv.so*"