[archiso] Add PXE NFS support

It add support for using *.sfs images via NFS.

It must be located after archiso_pxe_nbd in mkinitcpio.conf, in that way
NBD is the default.

New boot parameters:

    archiso_nfs_srv=IP:/path
         Set the NFS IP and path. Accepts ${pxeserver} as IP.

    archiso_nfs_opt= Sets NFS mount opts (comma separated)
                    Defaults to:
                      port            = as given by server portmap daemon
                      rsize           = 1024
                      wsize           = 1024
                      timeo           = 7
                      retrans         = 3
                      acregmin        = 3
                      acregmax        = 60
                      acdirmin        = 30
                      acdirmax        = 60
                      flags           = hard, nointr, noposix, cto, ac

:: Running Hook [archiso_pxe_common]
IP-Config: eth0 hardware address 52:54:00:12:34:57 mtu 1500
IP-Config: eth0 guessed broadcast address 192.168.0.255
IP-Config: eth0 guessed nameserver address 192.168.0.218
IP-Config: eth0 complete (from 192.168.0.218):
 address: 192.168.0.90     broadcast: 192.168.0.255    netmask: 255.255.255.0
 gateway: 192.168.0.218    dns0     : 192.168.0.218    dns1   : 0.0.0.0
 rootserver: 192.168.0.218 rootpath:
 filename  :
:: Running Hook [archiso_pxe_nbd]
:: Running Hook [archiso_pxe_curl]
:: Running Hook [archiso_pxe_nfs]
:: Mounting '192.168.0.77:/mnt/iso'

...
192.168.0.77:/mnt/iso/ on /run/archiso/bootmnt type nfs (rw,relatime,vers=3,rsize=524288,wsize=524288,namlen=255,hard,nolock,proto=tcp,port=65535,timeo=7,retrans=3,sec=sys,local_lock=all,addr=192.168.0.77)
...

My /etc/exports
/mnt/iso 192.168.0.90(ro,no_subtree_check,no_root_squash)

3 files changed, 44 insertions, 0 deletions

diff --git a/archiso/Makefile b/archiso/Makefile
index 0dbbbf8..11aff53 100644
--- a/archiso/Makefile
+++ b/archiso/Makefile
@@ -22,6 +22,8 @@ install-hooks:
 	install -D -m 644 install/archiso_pxe_nbd $(DESTDIR)/lib/initcpio/install/archiso_pxe_nbd
 	install -D -m 644 hooks/archiso_pxe_curl $(DESTDIR)/lib/initcpio/hooks/archiso_pxe_curl
 	install -D -m 644 install/archiso_pxe_curl $(DESTDIR)/lib/initcpio/install/archiso_pxe_curl
+	install -D -m 644 hooks/archiso_pxe_nfs $(DESTDIR)/lib/initcpio/hooks/archiso_pxe_nfs
+	install -D -m 644 install/archiso_pxe_nfs $(DESTDIR)/lib/initcpio/install/archiso_pxe_nfs
 	install -D -m 644 hooks/archiso_loop_mnt $(DESTDIR)/lib/initcpio/hooks/archiso_loop_mnt
 	install -D -m 644 install/archiso_loop_mnt $(DESTDIR)/lib/initcpio/install/archiso_loop_mnt
 
@@ -49,6 +51,8 @@ uninstall:
 	rm -f $(DESTDIR)/lib/initcpio/install/archiso_pxe_nbd
 	rm -f $(DESTDIR)/lib/initcpio/hooks/archiso_pxe_curl
 	rm -f $(DESTDIR)/lib/initcpio/install/archiso_pxe_curl
+	rm -f $(DESTDIR)/lib/initcpio/hooks/archiso_pxe_nfs
+	rm -f $(DESTDIR)/lib/initcpio/install/archiso_pxe_nfs
 	rm -f $(DESTDIR)/lib/initcpio/hooks/archiso_loop_mnt
 	rm -f $(DESTDIR)/lib/initcpio/install/archiso_loop_mnt
 	rm -rf $(DESTDIR)/usr/share/archiso/
diff --git a/archiso/hooks/archiso_pxe_nfs b/archiso/hooks/archiso_pxe_nfs
new file mode 100644
index 0000000..a053672
--- /dev/null
+++ b/archiso/hooks/archiso_pxe_nfs
@@ -0,0 +1,26 @@
+# vim: set ft=sh:
+
+run_hook() {
+    if [[ -n "${ip}" && -n "${archiso_nfs_srv}" ]]; then
+
+        archiso_nfs_srv=$(eval echo ${archiso_nfs_srv})
+        [[ -n "${archiso_nfs_opt}" ]] && archiso_nfs_opt="-o ${archiso_nfs_opt}"
+
+        mount_handler="archiso_nfs_mount_handler"
+    fi
+}
+
+archiso_nfs_mount_handler() {
+    newroot="${1}"
+    mkdir -p "/run/archiso/bootmnt"
+    msg ":: Mounting '${archiso_nfs_srv}'"
+    # Do not put "${archiso_nfs_opt}" nfsmount fails!
+    if ! nfsmount ${archiso_nfs_opt} "${archiso_nfs_srv}" "/run/archiso/bootmnt"; then
+        echo "ERROR: Mounting '${archiso_nfs_srv}'"
+        echo "   Falling back to interactive prompt"
+        echo "   You can try to fix the problem manually, log out when you are finished"
+        launch_interactive_shell
+    fi
+
+    archiso_mount_handler ${newroot}
+}
diff --git a/archiso/install/archiso_pxe_nfs b/archiso/install/archiso_pxe_nfs
new file mode 100644
index 0000000..52be9f3
--- /dev/null
+++ b/archiso/install/archiso_pxe_nfs
@@ -0,0 +1,14 @@
+# vim: set ft=sh:
+
+build() {
+    MODULES="nfs"
+    SCRIPT="archiso_pxe_nfs"
+
+    add_binary "/lib/initcpio/nfsmount" "/bin/nfsmount"
+}
+
+help() {
+    cat <<HELPEOF
+  This hook loads the necessary modules for boot via PXE and NFS.
+HELPEOF
+}