Rename parallel-debian/ to gnomeos/

gnomeos/.gitignore

@@ -0,0 +1 @@
+ostree_switch_root

gnomeos/0001-Support-OSTree.patch

@@ -0,0 +1,149 @@
+From e9cb0f0c6ef13773c823610f27a562bd54b2acd3 Mon Sep 17 00:00:00 2001
+From: Colin Walters <walters@verbum.org>
+Date: Mon, 24 Oct 2011 22:01:17 -0400
+Subject: [PATCH] Support OSTree
+
+See http://git.gnome.org/browse/ostree
+---
+ modules.d/95rootfs-block/mount-root.sh |   12 ++++++------
+ modules.d/99base/init                  |   32 ++++++++++++++++++++++----------
+ 2 files changed, 28 insertions(+), 16 deletions(-)
+
+diff --git a/modules.d/95rootfs-block/mount-root.sh b/modules.d/95rootfs-block/mount-root.sh
+index 2c89431..4f411da 100755
+--- a/modules.d/95rootfs-block/mount-root.sh
++++ b/modules.d/95rootfs-block/mount-root.sh
+@@ -34,8 +34,8 @@ mount_root() {
+ 
+     READONLY=
+     fsckoptions=
+-    if [ -f "$NEWROOT"/etc/sysconfig/readonly-root ]; then
+-        . "$NEWROOT"/etc/sysconfig/readonly-root
++    if [ -f "$NEWROOT_PREFIX"/etc/sysconfig/readonly-root ]; then
++        . "$NEWROOT_PREFIX"/etc/sysconfig/readonly-root
+     fi
+ 
+     if getargbool 0 "readonlyroot=" -y readonlyroot; then
+@@ -57,7 +57,7 @@ mount_root() {
+     if [ -f "$NEWROOT"/forcefsck ] || getargbool 0 forcefsck ; then
+         fsckoptions="-f $fsckoptions"
+     elif [ -f "$NEWROOT"/.autofsck ]; then
+-        [ -f "$NEWROOT"/etc/sysconfig/autofsck ] && . "$NEWROOT"/etc/sysconfig/autofsck
++        [ -f "$NEWROOT_PREFIX"/etc/sysconfig/autofsck ] && . "$NEWROOT_PREFIX"/etc/sysconfig/autofsck
+         if [ "$AUTOFSCK_DEF_CHECK" = "yes" ]; then
+             AUTOFSCK_OPT="$AUTOFSCK_OPT -f"
+         fi
+@@ -73,8 +73,8 @@ mount_root() {
+     rootopts=
+     if getargbool 1 rd.fstab -n rd_NO_FSTAB \
+         && ! getarg rootflags \
+-        && [ -f "$NEWROOT/etc/fstab" ] \
+-        && ! [ -L "$NEWROOT/etc/fstab" ]; then
++        && [ -f "$NEWROOT_PREFIX/etc/fstab" ] \
++        && ! [ -L "$NEWROOT_PREFIX/etc/fstab" ]; then
+         # if $NEWROOT/etc/fstab contains special mount options for
+         # the root filesystem,
+         # remount it with the proper options
+@@ -89,7 +89,7 @@ mount_root() {
+                 rootopts=$opts
+                 break
+             fi
+-        done < "$NEWROOT/etc/fstab"
++        done < "$NEWROOT_PREFIX/etc/fstab"
+ 
+         rootopts=$(filter_rootopts $rootopts)
+     fi
+diff --git a/modules.d/99base/init b/modules.d/99base/init
+index 36b2152..9636990 100755
+--- a/modules.d/99base/init
++++ b/modules.d/99base/init
+@@ -275,6 +275,13 @@ unset queuetriggered
+ unset main_loop
+ unset RDRETRY
+ 
++ostree=$(getarg ostree=)
++if test -n $ostree; then
++    NEWROOT_PREFIX=${NEWROOT}/ostree/$ostree
++else
++    NEWROOT_PREFIX=$NEWROOT
++fi
++
+ # pre-mount happens before we try to mount the root filesystem,
+ # and happens once.
+ getarg 'rd.break=pre-mount' 'rdbreak=pre-mount' && emergency_shell -n pre-mount "Break pre-mount"
+@@ -287,14 +294,15 @@ getarg 'rd.break=mount' 'rdbreak=mount' && emergency_shell -n mount "Break mount
+ i=0
+ while :; do
+     if ismounted "$NEWROOT"; then
+-        usable_root "$NEWROOT" && break;
++        echo "Checking usable $NEWROOT_PREFIX"
++        usable_root "$NEWROOT_PREFIX" && break;
+         umount "$NEWROOT"
+     fi
+     for f in $hookdir/mount/*.sh; do
+         [ -f "$f" ] && . "$f"
+         if ismounted "$NEWROOT"; then
+-            usable_root "$NEWROOT" && break;
+-            warn "$NEWROOT has no proper rootfs layout, ignoring and removing offending mount hook"
++            usable_root "$NEWROOT_PREFIX" && break;
++            warn "$NEWROOT_PREFIX has no proper rootfs layout, ignoring and removing offending mount hook"
+             umount "$NEWROOT"
+             rm -f "$f"
+         fi
+@@ -320,11 +328,11 @@ unset __usr_found
+ for i in "$(getarg real_init=)" "$(getarg init=)" /sbin/init /etc/init /init /bin/sh; do
+     [ -n "$i" ] || continue
+ 
+-    __p=$(readlink -m "$NEWROOT$i")
++    __p=$(readlink -m "$NEWROOT_PREFIX$i")
+     if [ -n "$__p" ] \
+         && [ "x$__usr_found" = "x" ] \
+         && [ ! -x "$__p" ] \
+-        && strstr "$__p" "$NEWROOT/usr" \
++        && strstr "$__p" "$NEWROOT_PREFIX/usr" \
+         ; then
+         # we have to mount /usr
+         while read dev mp fs opts rest; do
+@@ -333,14 +341,14 @@ for i in "$(getarg real_init=)" "$(getarg init=)" /sbin/init /etc/init /init /bi
+                 __usr_found="1"
+                 break
+             fi
+-        done < "$NEWROOT/etc/fstab" >> /etc/fstab
++        done < "$NEWROOT_PREFIX/etc/fstab" >> /etc/fstab
+         if [ "x$__usr_found" != "x" ]; then
+             info "Mounting /usr"
+-            mount "$NEWROOT/usr" 2>&1 | vinfo
++            mount "$NEWROOT_PREFIX/usr" 2>&1 | vinfo
+         fi
+     fi
+ 
+-    __p=$(readlink -f "$NEWROOT$i")
++    __p=$(readlink -f "$NEWROOT_PREFIX$i")
+     if [ -x "$__p" ]; then
+         INIT="$i"
+         break
+@@ -445,7 +453,11 @@ info "Switching root"
+ unset PS4
+ 
+ CAPSH=$(command -v capsh)
+-SWITCH_ROOT=$(command -v switch_root)
++if test -n "${ostree}"; then
++    SWITCH_ROOT=$(command -v ostree_switch_root)
++else
++    SWITCH_ROOT=$(command -v switch_root)
++fi
+ PATH=$OLDPATH
+ export PATH
+ 
+@@ -463,7 +475,7 @@ if [ -f /etc/capsdrop ]; then
+     }
+ else
+     unset RD_DEBUG
+-    exec $SWITCH_ROOT "$NEWROOT" "$INIT" $initargs || {
++    exec $SWITCH_ROOT "$NEWROOT" $ostree "$INIT" $initargs || {
+ 	warn "Something went very badly wrong in the initramfs.  Please "
+ 	warn "file a bug against dracut."
+ 	emergency_shell
+-- 
+1.7.6.4
+

gnomeos/README-testing-multiroot.md

@@ -0,0 +1,104 @@
+
+Experimenting with multiple roots
+---------------------------------
+
+	$ mkdir gnomeos-chroot 
+	$ qemu-img create gnomeos.raw 2G
+	$ mkfs.ext2 -F gnomeos.raw
+	$ mount -o loop gnomeos.raw gnomeos-chroot
+	$ debootstrap --arch=amd64 squeeze gnomeos-chroot
+
+<http://wiki.debian.org/QEMU#Setting_up_a_testing.2BAC8-unstable_system>
+
+Follow the steps for making a disk image, downloading the business
+card CD, booting it in QEMU and running through the installer.  Note I
+used the QCOW format, since it is more efficient.  Here are the steps
+I chose:
+
+	$ qemu-img create -f qcow2 debian.qcow 2G
+	$ qemu-kvm -hda debian.qcow -cdrom debian-testing-amd64-businesscard.iso -boot d -m 512
+
+Test that the image works after installation too, before you start
+modifying things below!  Remember to remove the -cdrom and -boot
+options from the installation QEMU command.  It should just look like
+this:
+
+$ qemu-kvm -hda debian.qcow -m 512
+
+
+Modifying the image
+-------------------
+
+You now have a disk image in debian.img, and the first partition
+should be ext4.
+
+The first thing I did was mount the image, and move the "read only"
+parts of the OS to a new directory "r0".
+
+	$ mkdir /mnt/debian
+	$ modprobe nbd max_part=8
+	$ qemu-nbd --connect=/dev/nbd0 debian.qcow
+	$ mount /dev/nbd0p1 /mnt/debian/
+	$ cd /mnt/debian
+	$ mkdir r0
+	$ DIRS="bin dev etc lib lib32 lib64 media mnt opt proc root run sbin selinux srv sys tmp usr"
+	$ mv $DIRS r0 
+	$ mkdir r0/{boot,var,home}
+	$ touch r0/{boot,var,home}/EMPTY
+
+Note that /boot, /home and /var are left shared; we create empty
+destination directories that will be mounted over.  Now with it still
+mounted, we need to move on to the next part - modifying the initrd.
+
+Then I started hacking on the initrd, making understand how to chroot
+to "r0".  I ended up with two patches - one to util-linux, and one to
+the "init" script in Debian's initrd.
+
+See:
+    0001-switch_root-Add-subroot-option.patch
+    0001-Add-support-for-subroot-option.patch
+
+$ git clone --depth=1 git://github.com/karelzak/util-linux.git
+$ cd util-linux
+$ patch -p1 -i ../0001-switch_root-Add-subroot-option.patch
+$ ./autogen.sh; ./configure ; make
+
+Now you have a modified "sys-utils/switch_root" binary.  Let's next
+patch the initrd and rebuild it:
+
+$ cd ..
+
+Make a backup:
+
+	$ mkdir initrd
+	$ cp /mnt/debian/boot/initrd.img-3.0.0-1-amd64{,.orig}
+
+Unpack, and patch:
+
+	$ zcat /mnt/debian/boot/initrd.img-3.0.0-1-amd64 | (cd initrd; cpio -d -i -v)
+	$ (cd initrd && patch -p1 -i ../0001-Add-support-for-subroot-option.patch)
+
+Repack:
+
+	$ (cd initrd; find | cpio -o -H newc) | gzip > /mnt/debian/boot/initrd.img-3.0.0-1-amd64.new
+	$ mv /mnt/debian/boot/initrd.img-3.0.0-1-amd64{.new,}
+
+Unmount:
+
+	$ umount /mnt/debian
+
+Running hacktree inside the system
+----------------------------------
+
+This means that after booting, every process would be in /r0 -
+including any hacktree process.  Assuming objects live in say
+/objects, we need some way for hacktree to switch things.  I think
+just chroot breakout would work.  This has the advantage the daemon
+can continue to use libraries from the active host.
+
+Note there is a self-reference here (as is present in Debian/Fedora
+etc.) - the update system would at present be shipped with the system
+itself.  Should they be independent?  That has advantages and
+disadvantages.  I think we should just try really really hard to avoid
+breaking hacktree in updates.
+

gnomeos/debian-setup.sh

@@ -0,0 +1,60 @@
+#!/bin/sh
+# This script sets up things we want to ship with the OS tree.  It should
+# NOT set up caches.  For example, do NOT run ldconfig in here.
+
+set -e
+set -x
+
+echo gnomeos >./etc/hostname
+
+cat >./etc/default/locale <<EOF
+LANG="en_US.UTF-8"
+EOF
+
+cp -p ./usr/share/sysvinit/inittab ./etc/inittab
+cp -p ./usr/share/base-files/nsswitch.conf ./etc/nsswitch.conf
+
+cat >./etc/pam.d/common-account <<EOF
+account [success=1 new_authtok_reqd=done default=ignore]        pam_unix.so 
+account requisite                       pam_deny.so
+account required                        pam_permit.so
+EOF
+cat >./etc/pam.d/common-auth <<EOF
+auth    [success=1 default=ignore]      pam_unix.so nullok_secure
+auth    requisite                       pam_deny.so
+auth    required                        pam_permit.so
+EOF
+cat >./etc/pam.d/common-password <<EOF
+password        [success=1 default=ignore]      pam_unix.so obscure sha512
+password        requisite                       pam_deny.so
+password        required                        pam_permit.so
+EOF
+cat >./etc/pam.d/common-session <<EOF
+session [default=1]                     pam_permit.so
+session requisite                       pam_deny.so
+session required                        pam_permit.so
+session required        pam_unix.so 
+EOF
+
+# base-passwd
+cp -p ./usr/share/base-passwd/passwd.master ./etc/passwd
+cp -p ./usr/share/base-passwd/group.master ./etc/group
+
+# Service rc.d defaults
+setuprc () {
+    name=$1
+    shift
+    type=$1
+    shift
+    priority=$1
+    shift
+    
+    for x in $@; do
+	ln -s ../init.d/$name ./etc/rc${x}.d/${type}${priority}${name}
+    done
+}
+    
+setuprc rsyslog S 10 2 3 4 5
+setuprc rsyslog S 30 0 6 
+setuprc rsyslog K 90 1
+setuprc cron S 89 2 3 4 5

gnomeos/gnomeos-install.sh

@@ -0,0 +1,41 @@
+#!/bin/sh
+# -*- indent-tabs-mode: nil; -*-
+# Install built ostree image to current system
+#
+# Copyright (C) 2011 Colin Walters <walters@verbum.org>
+#
+# This program 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 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+set -e
+set -x
+
+SRCDIR=`dirname $0`
+WORKDIR=`pwd`
+
+OBJ=gnomeos-initrd.img
+if ! test -f ${OBJ}; then
+    echo "Error: couldn't find '$OBJ'. Run gnomeos-make-image.sh"
+    exit 1
+fi
+
+if test -d /ostree; then
+    echo "/ostree already exists"
+    exit 1
+fi
+
+cp -a gnomeos-fs/ostree /
+initrd=`readlink gnomeos-initrd.img`
+cp ${initrd} /boot
+grubby --title "GNOME OS" --add-kernel=$kernel --copy-default --initrd=/boot/${initrd}

gnomeos/gnomeos-make-base.sh

@@ -0,0 +1,202 @@
+#!/bin/sh
+# -*- indent-tabs-mode: nil; -*-
+# Generate a root filesystem image
+#
+# Copyright (C) 2011 Colin Walters <walters@verbum.org>
+#
+# This program 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 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+set -e
+set -x
+
+SRCDIR=`dirname $0`
+WORKDIR=`pwd`
+
+DEPENDS="debootstrap"
+
+for x in $DEPENDS; do
+    if ! command -v $x; then
+        cat <<EOF
+Couldn't find required dependency $x
+EOF
+        exit 1
+    fi
+done
+
+if test $(id -u) == 0; then
+    echo "Should not run this script as root."
+    exit 1
+fi
+
+if test -z "${OSTREE}"; then
+    OSTREE=`command -v ostree || true`
+fi
+if test -z "${OSTREE}"; then
+    cat <<EOF
+ERROR:
+Couldn't find ostree; you can set the OSTREE environment variable to point to it
+e.g.: OSTREE=~user/checkout/ostree/ostree $0
+EOF
+    exit 1
+fi
+
+if test -z "$DRACUT"; then
+    if ! test -d dracut; then
+        cat <<EOF
+Checking out and patching dracut...
+EOF
+        git clone git://git.kernel.org/pub/scm/boot/dracut/dracut.git
+        (cd dracut; git am $SRCDIR/0001-Support-OSTree.patch)
+        (cd dracut; make)
+    fi
+    DRACUT=`pwd`/dracut/dracut
+fi
+
+case `uname -p` in
+    x86_64)
+        ARCH=amd64
+        ;;
+    *)
+        echo "Unsupported architecture"
+        ;;
+esac;
+
+DEBTARGET=wheezy
+
+INITRD_MOVE_MOUNTS="dev proc sys"
+TOPROOT_BIND_MOUNTS="boot home root tmp"
+OSTREE_BIND_MOUNTS="var"
+MOVE_MOUNTS="selinux mnt media"
+READONLY_BIND_MOUNTS="bin etc lib lib32 lib64 sbin usr"
+
+cd ${WORKDIR}
+OBJ=debootstrap-$DEBTARGET
+if ! test -d ${OBJ} ; then
+    echo "Creating $DEBTARGET.img"
+    mkdir -p ${OBJ}.tmp
+    debootstrap --download-only --arch $ARCH $DEBTARGET ${OBJ}.tmp
+    mv ${OBJ}.tmp ${OBJ}
+fi
+
+cd ${WORKDIR}
+OBJ=$DEBTARGET-fs
+if ! test -d ${OBJ}; then
+    rm -rf ${OBJ}.tmp
+    mkdir ${OBJ}.tmp
+
+    cd ${OBJ}.tmp;
+    mkdir -m 0755 $INITRD_MOVE_MOUNTS $TOPROOT_BIND_MOUNTS
+    chmod a=rwxt tmp
+
+    mkdir ostree
+
+    mkdir -p -m 0755 ostree/var/{log,run}
+
+    mkdir ostree/repo
+
+    $OSTREE --repo=ostree/repo init 
+    
+    BRANCHES=""
+
+    mkdir ostree/worktree
+    cd ostree/worktree
+    mkdir -m 0755 $INITRD_MOVE_MOUNTS $TOPROOT_BIND_MOUNTS $OSTREE_BIND_MOUNTS $READONLY_BIND_MOUNTS $MOVE_MOUNTS sysroot
+    chmod a=rwxt tmp
+    $OSTREE --repo=../repo commit -b gnomeos-filesystem -s "Base filesystem layout"
+    BRANCHES="$BRANCHES gnomeos-filesystem"
+    cd ..
+    rm -rf worktree
+
+    for d in ${WORKDIR}/debootstrap-$DEBTARGET/var/cache/apt/archives/*.deb; do
+        bn=$(basename $d)
+        debname=$(echo $bn | cut -f 1 -d _)
+        debversion=$(echo $bn | cut -f 2 -d _)
+        archivename="archive-${debname}"
+        rm -rf worktree; mkdir worktree;
+        cd worktree;
+        mkdir data;
+        ar x $d;
+        tar -x -z -C data -f data.tar.gz;
+        cd data;
+        $OSTREE --repo=../../repo commit -b "${archivename}" -s "Version ${debversion}"
+        BRANCHES="$BRANCHES $archivename"
+        cd ../..
+    done
+    rm -rf worktree
+
+    $OSTREE --repo=repo compose --out-metadata=./compose-meta worktree $BRANCHES
+    cd worktree
+    $OSTREE --repo=../repo commit --metadata-variant=../compose-meta -b gnomeos -s "Compose of Debian $DEBTARGET"
+    cd ..
+    rm -rf worktree
+    
+    cd ${WORKDIR}
+    if test -d ${OBJ}; then
+        mv ${OBJ} ${OBJ}.old
+    fi
+    mv ${OBJ}.tmp ${OBJ}
+    rm -rf ${OBJ}.old
+fi
+
+# TODO download source for above
+# TODO download build dependencies for above
+
+cd ${WORKDIR}
+OBJ=gnomeos-fs
+if ! test -d ${OBJ}; then
+    rm -rf ${OBJ}.tmp
+    cp -al $DEBTARGET-fs ${OBJ}.tmp
+    cd ${OBJ}.tmp/ostree;
+    rm -rf worktree
+    $OSTREE --repo=repo checkout gnomeos worktree
+    cd worktree
+    ${SRCDIR}/debian-setup.sh
+    $OSTREE --repo=../repo commit -b gnomeos -s "Run debian-setup.sh"
+    cd ..
+    rm -rf worktree
+
+    rev=$($OSTREE --repo=repo rev-parse gnomeos);
+    $OSTREE --repo=repo checkout ${rev} gnomeos-${rev}
+    $OSTREE --repo=repo run-triggers gnomeos-${rev}
+    ln -s gnomeos-${rev} current
+    
+    cd ${WORKDIR}
+    if test -d ${OBJ}; then
+        mv ${OBJ} ${OBJ}.old
+    fi
+    mv ${OBJ}.tmp ${OBJ}
+    rm -rf ${OBJ}.old
+fi
+
+cd ${WORKDIR}
+cp ${SRCDIR}/ostree_switch_root ${WORKDIR}
+
+kv=`uname -r`
+kernel=/boot/vmlinuz-${kv}
+if ! test -f "${kernel}"; then
+    cat <<EOF
+Failed to find ${kernel}
+EOF
+fi
+
+cd ${WORKDIR}
+OBJ=gnomeos-initrd.img
+VOBJ=gnomeos-initrd-${kv}.img
+if ! test -f ${OBJ}; then
+    rm -f ${OBJ}.tmp ${VOBJ}.tmp
+    $DRACUT -l -v -o plymouth --include `pwd`/ostree_switch_root /sbin/ostree_switch_root ${VOBJ}.tmp
+    mv ${VOBJ}.tmp ${VOBJ}
+    ln -sf ${VOBJ} gnomeos-initrd.img
+fi

gnomeos/gnomeos-run.sh

@@ -0,0 +1,48 @@
+#!/bin/sh
+# -*- indent-tabs-mode: nil; -*-
+# Run built image in QEMU 
+#
+# Copyright (C) 2011 Colin Walters <walters@verbum.org>
+#
+# This program 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 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+set -e
+set -x
+
+SRCDIR=`dirname $0`
+WORKDIR=`pwd`
+
+if ! test -d gnomeos-fs; then
+    echo "Error: couldn't find gnomeos-fs. Run gnomeos-make-image.sh"
+    exit 1
+fi
+
+OBJ=gnomeos-fs.img
+if (! test -f ${OBJ}) || test gnomeos-fs -nt ${OBJ}; then
+    rm -f ${OBJ}.tmp
+    qemu-img create ${OBJ}.tmp 2G
+    mkfs.ext4 -q -F ${OBJ}.tmp
+    mkdir -p fs
+    umount fs || true
+    mount -o loop ${OBJ}.tmp fs
+    cp -a gnomeos-fs/* fs
+    umount fs
+    mv ${OBJ}.tmp ${OBJ}
+fi
+
+kv=`uname -r`
+kernel=/boot/vmlinuz-${kv}
+
+exec qemu-kvm -kernel ${kernel} -initrd gnomeos-initrd.img -hda gnomeos-fs.img -append "root=/dev/sda ostree=current $1"

gnomeos/ostree_switch_root.c

@@ -0,0 +1,309 @@
+/* -*- c-file-style: "linux" -*-
+ * ostree_switch_root.c - switch to new root directory and start init.
+ * Copyright 2011 Colin Walters <walters@verbum.org>
+ *
+ * Based of switch_root.c from util-linux.
+ * Copyright 2002-2009 Red Hat, Inc.  All rights reserved.
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *	Peter Jones <pjones@redhat.com>
+ *	Jeremy Katz <katzj@redhat.com>
+ *	Colin Walters <walters@verbum.org>
+ */
+#define _GNU_SOURCE
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <dirent.h>
+
+static int
+perrorv (const char *format, ...) __attribute__ ((format (printf, 1, 2)));
+
+static int
+perrorv (const char *format, ...)
+{
+	va_list args;
+	char buf[PATH_MAX];
+	char *p;
+
+	p = strerror_r (errno, buf, sizeof (buf));
+
+	va_start (args, format);
+
+	vfprintf (stderr, format, args);
+	fprintf (stderr, ": %s\n", p);
+	fflush (stderr);
+
+	va_end (args);
+
+	sleep (3);
+	
+	return 0;
+}
+
+/* remove all files/directories below dirName -- don't cross mountpoints */
+static int recursiveRemove(int fd)
+{
+	struct stat rb;
+	DIR *dir;
+	int rc = -1;
+	int dfd;
+
+	if (!(dir = fdopendir(fd))) {
+		perrorv("failed to open directory");
+		goto done;
+	}
+
+	/* fdopendir() precludes us from continuing to use the input fd */
+	dfd = dirfd(dir);
+
+	if (fstat(dfd, &rb)) {
+		perrorv("failed to stat directory");
+		goto done;
+	}
+
+	while(1) {
+		struct dirent *d;
+
+		errno = 0;
+		if (!(d = readdir(dir))) {
+			if (errno) {
+				perrorv("failed to read directory");
+				goto done;
+			}
+			break;	/* end of directory */
+		}
+
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+
+		if (d->d_type == DT_DIR) {
+			struct stat sb;
+
+			if (fstatat(dfd, d->d_name, &sb, AT_SYMLINK_NOFOLLOW)) {
+				perrorv("failed to stat %s", d->d_name);
+				continue;
+			}
+
+			/* remove subdirectories if device is same as dir */
+			if (sb.st_dev == rb.st_dev) {
+				int cfd;
+
+				cfd = openat(dfd, d->d_name, O_RDONLY);
+				if (cfd >= 0) {
+					recursiveRemove(cfd);
+					close(cfd);
+				}
+			} else
+				continue;
+		}
+
+		if (unlinkat(dfd, d->d_name,
+			     d->d_type == DT_DIR ? AT_REMOVEDIR : 0))
+			perrorv("failed to unlink %s", d->d_name);
+	}
+
+	rc = 0;	/* success */
+
+done:
+	if (dir)
+		closedir(dir);
+	return rc;
+}
+
+static int make_readonly(const char *tree)
+{
+	struct stat stbuf;
+	/* Ignore nonexistent directories for now;
+	 * some installs won't have e.g. lib64
+	 */
+	if (stat (tree, &stbuf) < 0)
+		return 0;
+	if (mount(tree, tree, NULL, MS_BIND, NULL) < 0) {
+		perrorv("Failed to do initial RO bind mount %s", tree);
+		return -1;
+	}
+	if (mount(tree, tree, NULL, MS_BIND | MS_REMOUNT | MS_RDONLY, NULL) < 0) {
+		perrorv("Failed to remount RO bind mount %s", tree);
+		return -1;
+	}
+	return 0;
+}
+
+
+static int switchroot(const char *newroot, const char *subroot)
+{
+	const char *initrd_move_mounts[] = { "/dev", "/proc", "/sys", NULL };
+	const char *toproot_bind_mounts[] = { "/boot", "/home", "/root", "/tmp", NULL };
+	const char *ostree_bind_mounts[] = { "/var", NULL };
+	const char *readonly_bind_mounts[] = { "/bin", "/etc", "/lib",
+					       "/lib32", "/lib64", "/sbin",
+					       "/usr",
+					       NULL };
+	int i;
+	int orig_cfd;
+	int new_cfd;
+	int subroot_cfd;
+	pid_t pid;
+	char subroot_path[PATH_MAX];
+	char srcpath[PATH_MAX];
+	char destpath[PATH_MAX];
+
+	fprintf (stderr, "switching to root %s subroot: %s\n", newroot, subroot);
+
+	orig_cfd = open("/", O_RDONLY);
+	new_cfd = open(newroot, O_RDONLY);
+
+	/* For now just remount the rootfs r/w.  Should definitely
+	 * handle this better later... (famous last words)
+	 */
+	if (mount(newroot, newroot, NULL, MS_REMOUNT, NULL) < 0) {
+		perrorv("failed to remount %s read/write", newroot);
+		return -1;
+	}
+
+	snprintf(subroot_path, sizeof(subroot_path), "%s/ostree/%s", newroot, subroot);
+	subroot_cfd = open(subroot_path, O_RDONLY);
+	if (subroot_cfd < 0) {
+		perrorv("failed to open subroot %s", subroot_path);
+		return -1;
+	}
+
+	for (i = 0; initrd_move_mounts[i] != NULL; i++) {
+		snprintf(destpath, sizeof(destpath), "%s%s", subroot_path, initrd_move_mounts[i]);
+
+		if (mount(initrd_move_mounts[i], destpath, NULL, MS_MOVE, NULL) < 0) {
+			perrorv("failed to move initramfs mount %s to %s",
+				initrd_move_mounts[i], destpath);
+			umount2(initrd_move_mounts[i], MNT_FORCE);
+		}
+	}
+
+	for (i = 0; toproot_bind_mounts[i] != NULL; i++) {
+		snprintf(srcpath, sizeof(srcpath), "%s%s", newroot, toproot_bind_mounts[i]);
+		snprintf(destpath, sizeof(destpath), "%s/%s", subroot_path, toproot_bind_mounts[i]);
+		if (mount(srcpath, destpath, NULL, MS_BIND & ~MS_RDONLY, NULL) < 0) {
+			perrorv("failed to bind mount (class:toproot) %s to %s", srcpath, destpath);
+			return -1;
+		}
+	}
+
+	for (i = 0; ostree_bind_mounts[i] != NULL; i++) {
+		snprintf(srcpath, sizeof(srcpath), "%s/ostree%s", newroot, ostree_bind_mounts[i]);
+		snprintf(destpath, sizeof(destpath), "%s%s", subroot_path, ostree_bind_mounts[i]);
+		if (mount(srcpath, destpath, NULL, MS_BIND & ~MS_RDONLY, NULL) < 0) {
+			perrorv("failed to bind mount (class:bind) %s to %s", srcpath, destpath);
+			return -1;
+		}
+	}
+
+	snprintf(destpath, sizeof(destpath), "%s/sysroot", subroot_path);
+	if (mount(newroot, destpath, NULL, MS_BIND, NULL) < 0) {
+		perrorv("Failed bind mount sysroot");
+		return -1;
+	}
+
+	if (chdir(newroot)) {
+		perrorv("failed to change directory to %s", newroot);
+		return -1;
+	}
+
+	if (mount(newroot, "/", NULL, MS_MOVE, NULL) < 0) {
+		perrorv("failed to mount moving %s to /", newroot);
+		return -1;
+	}
+
+	if (fchdir (new_cfd) < 0) {
+		perrorv("failed to fchdir back to root");
+		return -1;
+	}
+
+	snprintf(destpath, sizeof(destpath), "ostree/%s", subroot);
+	if (chroot(destpath) < 0) {
+		perrorv("failed to change root to %s", destpath);
+		return -1;
+	}
+
+	if (chdir ("/") < 0) {
+		perrorv("failed to chdir to subroot");
+		return -1;
+	}
+
+	for (i = 0; readonly_bind_mounts[i] != NULL; i++) {
+		if (make_readonly(readonly_bind_mounts[i]) < 0) {
+			return -1;
+		}
+	}
+
+	if (orig_cfd >= 0) {
+		pid = fork();
+		if (pid <= 0) {
+			recursiveRemove(orig_cfd);
+			if (pid == 0)
+				exit(EXIT_SUCCESS);
+		}
+		close(orig_cfd);
+	}
+	close(new_cfd);
+	return 0;
+}
+
+static void usage(FILE *output)
+{
+	fprintf(output, "usage: %s <newrootdir> <init> <args to init>\n",
+			program_invocation_short_name);
+	exit(output == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int main(int argc, char *argv[])
+{
+	char *newroot, *subroot, *init, **initargs;
+
+	fflush (stderr);
+	if (argc < 4)
+		usage(stderr);
+
+	if ((!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")))
+		usage(stdout);
+
+	newroot = argv[1];
+	subroot = argv[2];
+	init = argv[3];
+	initargs = &argv[3];
+
+	if (!*newroot || !*subroot || !*init)
+		usage(stderr);
+
+	if (switchroot(newroot, subroot))
+		exit(1);
+
+	if (access(init, X_OK))
+		perrorv("cannot access %s", init);
+
+	execv(init, initargs);
+	perrorv("Failed to exec init '%s'", init);
+	exit(1);
+}
+