gnu: linux-initrd: Add (guix build linux-initrd) and use it.

* gnu/packages/linux-initrd.scm (qemu-initrd): Add #:modules argument.
  Factorize and move some of the code to...
* guix/build/linux-initrd.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.

1 files changed, 107 insertions, 0 deletions

diff --git a/guix/build/linux-initrd.scm b/guix/build/linux-initrd.scm
new file mode 100644
index 0000000000..274eef7ff3
--- /dev/null
+++ b/guix/build/linux-initrd.scm
@@ -0,0 +1,107 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build linux-initrd)
+  #:use-module (rnrs io ports)
+  #:use-module (system foreign)
+  #:export (mount-essential-file-systems
+            linux-command-line
+            configure-qemu-networking
+            mount-qemu-smb-share
+            load-linux-module*
+            device-number))
+
+;;; Commentary:
+;;;
+;;; Utility procedures useful in a Linux initial RAM disk (initrd).  Note that
+;;; many of these use procedures not yet available in vanilla Guile (`mount',
+;;; `load-linux-module', etc.); these are provided by a Guile patch used in
+;;; the GNU distribution.
+;;;
+;;; Code:
+
+(define* (mount-essential-file-systems #:key (root "/"))
+  "Mount /proc and /sys under ROOT."
+  (define (scope dir)
+    (string-append root
+                   (if (string-suffix? "/" root)
+                       ""
+                       "/")
+                   dir))
+
+  (unless (file-exists? (scope "proc"))
+    (mkdir (scope "proc")))
+  (mount "none" (scope "proc") "proc")
+
+  (unless (file-exists? (scope "sys"))
+    (mkdir (scope "sys")))
+  (mount "none" (scope "sys") "sysfs"))
+
+(define (linux-command-line)
+  "Return the Linux kernel command line as a list of strings."
+  (string-tokenize
+   (call-with-input-file "/proc/cmdline"
+     get-string-all)))
+
+(define %host-qemu-ipv4-address
+  (inet-pton AF_INET "10.0.2.10"))
+
+(define* (configure-qemu-networking #:optional (interface "eth0"))
+  "Setup the INTERFACE network interface and /etc/resolv.conf according to
+QEMU's default networking settings (see net/slirp.c in QEMU for default
+networking values.)  Return #t if INTERFACE is up, #f otherwise."
+  (display "configuring QEMU networking...\n")
+  (let* ((sock    (socket AF_INET SOCK_STREAM 0))
+         (address (make-socket-address AF_INET %host-qemu-ipv4-address 0))
+         (flags   (network-interface-flags sock interface)))
+    (set-network-interface-address sock interface address)
+    (set-network-interface-flags sock interface (logior flags IFF_UP))
+
+    (unless (file-exists? "/etc")
+      (mkdir "/etc"))
+    (call-with-output-file "/etc/resolv.conf"
+      (lambda (p)
+        (display "nameserver 10.0.2.3\n" p)))
+
+    (logand (network-interface-flags sock interface) IFF_UP)))
+
+(define (mount-qemu-smb-share share mount-point)
+  "Mount QEMU's CIFS/SMB SHARE at MOUNT-POINT.
+
+Vanilla QEMU's `-smb' option just exports a /qemu share, whereas our
+`qemu-with-multiple-smb-shares' package exports the /xchg and /store shares
+ (the latter allows the store to be shared between the host and guest.)"
+
+  (format #t "mounting QEMU's SMB share `~a'...\n" share)
+  (let ((server "10.0.2.4"))
+    (mount (string-append "//" server share) mount-point "cifs" 0
+           (string->pointer "guest,sec=none"))))
+
+(define (load-linux-module* file)
+  "Load Linux module from FILE, the name of a `.ko' file."
+  (define (slurp module)
+    (call-with-input-file file get-bytevector-all))
+
+  (load-linux-module (slurp file)))
+
+(define (device-number major minor)
+  "Return the device number for the device with MAJOR and MINOR, for use as
+the last argument of `mknod'."
+  (+ (* major 256) minor))
+
+;;; linux-initrd.scm ends here