initalize buildroot later, and out outside of hooks

mkinitcpio needs to be able to more tightly control the layout of the
image. By moving this outside the control of the base hook, it's more
reasonable to believe that a drop-in replacement for the base hook could
be written, as it now only contains the utilities required for the /init
that it provides.

Being that initialize_buildroot is outside of a hook, we can make "raw"
calls to coreutils that create the directories and symlinks, saving some
overhead and forking.

This also symlinks /usr/local/{lib,bin} into the common /usr/lib and
/usr/bin, respectively, so that there's always a way to override libs
and bins, and they're automatically pulled into our strict early init
path of /usr/bin.

Finally, we lump all this generally a little "later" in the early setup.
This addresses an unseen "bug" wherein an extra temp directory that
never gets used is created when leveraging a preset.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/functions b/functions
index e9fb81a..e17e46e 100644
--- a/functions
+++ b/functions
@@ -606,6 +606,32 @@ write_image_config() {
     ) >"$BUILDROOT/config"
 }
 
+initialize_buildroot() {
+    # creates a temporary directory for the buildroot and initialize it with a
+    # basic set of necessary directories and symlinks
+
+    local workdir= kernver=$1
+
+    if ! workdir=$(mktemp -d --tmpdir mkinitcpio.XXXXXX); then
+        error 'Failed to create temporary working directory in %s' "${TMPDIR:-/tmp}"
+        return 1
+    fi
+
+    # base directory structure
+    install -dm755 "$workdir/root"/{new_root,proc,sys,dev,run,tmp,usr/{local,lib,bin}}
+    ln -s "usr/lib" "$workdir/root/lib"
+    ln -s "../lib"  "$workdir/root/usr/local/lib"
+    ln -s "bin"     "$workdir/root/usr/sbin"
+    ln -s "usr/bin" "$workdir/root/bin"
+    ln -s "usr/bin" "$workdir/root/sbin"
+    ln -s "../bin"  "$workdir/root/usr/local/bin"
+
+    # kernel module dir
+    install -dm755 "$workdir/root/usr/lib/modules/$kernver/kernel"
+
+    printf '%s' "$workdir"
+}
+
 run_build_hook() {
     local hook=$1 script= realscript=
     local MODULES= BINARIES= FILES= SCRIPT=