From 40f0cebe642b333c39afd6b1cc8a9b477545ed1a Mon Sep 17 00:00:00 2001
From: Jonathon Anderson <janderson@ciq.com>
Date: Wed, 29 Oct 2025 20:41:05 -0600
Subject: [PATCH] Configure destination of grub.cfg at overlay render time

Signed-off-by: Jonathon Anderson <janderson@ciq.com>
---
 CHANGELOG.md                                      |  2 ++
 Makefile                                          |  1 -
 internal/pkg/overlay/overlay.go                   | 15 ++++++++++++++-
 .../host/rootfs/grub.cfg.ww                       |  1 +
 4 files changed, 17 insertions(+), 2 deletions(-)
 rename etc/grub/chainload.ww => overlays/host/rootfs/grub.cfg.ww (94%)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f221965d..af644df3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Change the DHCP server package used on openeuler 24.03 to dnsmasq
 - Added configurable Serial over LAN speed via IPMI `bit-rate` tag in `50-ipmi` template
 - Manage SELinux context of TFTP directory. #1997
+- Dynamically write `$tftpdir/warewulf/grub.cfg` to the configured value from `warewulf.conf`
+- Absolute paths specified with `{{ file }}` in an overlay now write to that absolute path.
 
 ### Fixed
 
diff --git a/Makefile b/Makefile
index 89bbf4e5..01193712 100644
--- a/Makefile
+++ b/Makefile
@@ -204,7 +204,6 @@ install: build docs ## Install Warewulf from source
 	for f in etc/ipxe/*.ipxe; do install -m 0644 $$f $(DESTDIR)$(WWCONFIGDIR)/ipxe/; done
 	for f in lib/warewulf/bmc/*.tmpl; do install -m 0644 $$f $(DESTDIR)$(DATADIR)/warewulf/bmc; done
 	install -m 0644 etc/grub/grub.cfg.ww $(DESTDIR)$(WWCONFIGDIR)/grub/grub.cfg.ww
-	install -m 0644 etc/grub/chainload.ww $(DESTDIR)$(DATADIR)/warewulf/overlays/host/rootfs$(TFTPDIR)/warewulf/grub.cfg.ww
 	install -m 0644 etc/logrotate.d/warewulfd.conf $(DESTDIR)$(LOGROTATEDIR)/warewulfd.conf
 	(cd overlays && find * -path '*/internal' -prune -o -type f -exec install -D -m 0644 {} $(DESTDIR)$(DATADIR)/warewulf/overlays/{} \;)
 	(cd overlays && find * -path '*/internal' -prune -o -type d -exec mkdir -pv $(DESTDIR)$(DATADIR)/warewulf/overlays/{} \;)
diff --git a/internal/pkg/overlay/overlay.go b/internal/pkg/overlay/overlay.go
index 0ce80557..c0c38547 100644
--- a/internal/pkg/overlay/overlay.go
+++ b/internal/pkg/overlay/overlay.go
@@ -571,7 +571,20 @@ func BuildOverlayIndir(nodeData node.Node, allNodes []node.Node, overlayNames []
 							}
 							fileBuffer.Reset()
 						}
-						outputPath = path.Join(path.Dir(originalOutputPath), filenameFromTemplate[0][1])
+						if path.IsAbs(filenameFromTemplate[0][1]) {
+							outputPath = filenameFromTemplate[0][1]
+							// Create parent directory for absolute paths
+							parentDir := path.Dir(outputPath)
+							sourceDirInfo, err := os.Stat(path.Dir(walkPath))
+							if err != nil {
+								return fmt.Errorf("could not stat source directory: %w", err)
+							}
+							if err := os.MkdirAll(parentDir, sourceDirInfo.Mode()); err != nil {
+								return fmt.Errorf("could not create parent directory for absolute path: %w", err)
+							}
+						} else {
+							outputPath = path.Join(path.Dir(originalOutputPath), filenameFromTemplate[0][1])
+						}
 						writingToNamedFile = true
 						isLink = false
 					} else {
diff --git a/etc/grub/chainload.ww b/overlays/host/rootfs/grub.cfg.ww
similarity index 94%
rename from etc/grub/chainload.ww
rename to overlays/host/rootfs/grub.cfg.ww
index 3938132e..76f9ad35 100644
--- a/etc/grub/chainload.ww
+++ b/overlays/host/rootfs/grub.cfg.ww
@@ -1,3 +1,4 @@
+{{ file (print .Tftp.TftpRoot "/warewulf/grub.cfg") }}
 # This file is autogenerated by warewulf
 # Host:   {{ .BuildHost }}
 # Time:   {{ .BuildTime }}