Fix up GPT partition tables automatically

.gitlab-ci.yml

@@ -1,6 +1,7 @@
 checks:tests:
   after_script:
   - (cd qrexec-lib; gcov *.c || :)
+  - (cd gptfixer; gcov *.c || :)
   - ./ci/codecov-wrapper --gcov
   before_script:
   - sudo dnf install -y python3-pip 'pkgconfig(icu-uc)' sequoia-sqv
@@ -11,16 +12,11 @@ checks:tests:
   - python3 -m coverage run -m unittest discover -v imgconverter -p test.py
   - export CFLAGS="--coverage -DCOVERAGE" LDFLAGS=--coverage
   - make -C qrexec-lib check NO_REBUILD_TABLE=1
+  - gptfixer/test.sh
   stage: checks
   tags:
   - docker
 include:
-- file: /r4.1/gitlab-base.yml
-  project: QubesOS/qubes-continuous-integration
-- file: /r4.1/gitlab-dom0.yml
-  project: QubesOS/qubes-continuous-integration
-- file: /r4.1/gitlab-vm.yml
-  project: QubesOS/qubes-continuous-integration
 - file: /r4.2/gitlab-base.yml
   project: QubesOS/qubes-continuous-integration
 - file: /r4.2/gitlab-host.yml

Makefile

@@ -1,7 +1,10 @@
+SBINDIR ?= /usr/sbin
 LIBDIR ?= /usr/lib64
 SCRIPTSDIR ?= /usr/lib/qubes
 SYSLIBDIR ?= /usr/lib
 INCLUDEDIR ?= /usr/include
+CFLAGS ?= -Wall -Wextra -Werror -O3 -g3 -Werror=format=2
+CC ?= gcc
 
 export LIBDIR SCRIPTSDIR SYSLIBDIR INCLUDEDIR
 .PHONY: all selinux install install-selinux install-fedora-kernel-support install-debian-kernel-support clean
@@ -35,6 +38,14 @@ install-debian-kernel-support:
 	$(MAKE) -C dracut install
 	$(MAKE) -C grub install-debian
 
+install-gptfix: gptfixer/gpt
+	install -D gptfixer/gpt $(DESTDIR)$(SBINDIR)/gptfix
+gptfixer/gpt_LDLIBS := -lz
+gptfixer/gpt_CFLAGS := -D_GNU_SOURCE -fno-strict-aliasing -fno-delete-null-pointer-checks -fno-strict-overflow
+%: %.c Makefile
+	$(CC) $($(@)_CFLAGS) -o $@ $< $(CFLAGS) -MD -MP -MF [email protected] $($(@)_LDLIBS)
+-include gptfixer/*.dep
+
 clean:
 	$(MAKE) -C qrexec-lib clean
 	$(MAKE) -C qmemman clean

archlinux/PKGBUILD.in

@@ -62,4 +62,5 @@ package_qubes-vm-kernel-support() {
     install -m 611 "${srcdir}/${_pkgnvr}/archlinux/PKGBUILD-initcpio-hook.sh" "${pkgdir}/usr/lib/initcpio/hooks/qubes"
     install -m 755 "${srcdir}/${_pkgnvr}/dracut/full-dmroot/qubes_cow_setup.sh" "${pkgdir}/usr/lib/qubes/qubes_cow_setup.sh"
     install -m 0644 "${srcdir}/${_pkgnvr}/grub/grub.qubes-kernel-vm-support" "${pkgdir}/etc/default/grub.qubes-kernel-vm-support"
+    make install-gptfix SBINDIR=/usr/bin "DESTDIR=$pkgdir"
 }

debian/control

@@ -7,7 +7,8 @@ Build-Depends:
  libxen-dev,
  pkg-config,
  python3-setuptools,
- libicu-dev
+ libicu-dev,
+ libz-dev,
 Standards-Version: 4.4.0.1
 Homepage: https://www.qubes-os.org
 Vcs-Git: https://github.com/QubesOS/qubes-linux-utils.git

debian/qubes-kernel-vm-support.install

@@ -7,3 +7,4 @@ usr/lib/dracut/modules.d/90qubes-vm-modules/*
 usr/lib/dracut/modules.d/90qubes-vm-simple/*
 usr/lib/dracut/modules.d/80xen-scrub-pages/*
 etc/default/grub.d/30-qubes-kernel-vm-support.cfg
+usr/sbin/gptfix

debian/rules

@@ -15,6 +15,7 @@ override_dh_auto_build:
 override_dh_auto_install:
 	make install LIBDIR=/usr/lib DEBIANBUILD=1 PYTHON_PREFIX_ARG=--install-layout=deb
 	make install-debian-kernel-support LIBDIR=/usr/lib DEBIANBUILD=1 
+	make install-gptfix SBINDIR=/usr/sbin
 
 override_dh_install:
 	dh_install --fail-missing

dracut/full-dmroot/module-setup.sh

@@ -18,5 +18,6 @@ install() {
     inst_multiple \
         sfdisk \
         swapon \
-        mkswap
+        mkswap \
+        gptfix
 }

dracut/full-dmroot/qubes_cow_setup.sh

@@ -54,19 +54,32 @@ modprobe xenblk || modprobe xen-blkfront || warn "Qubes: Cannot load Xen Block F
 
 log_begin "Waiting for /dev/xvda* devices..."
 udevadm settle --exit-if-exists=/dev/xvda
-log_end
 
 # prefer partition if exists
-if [ -b /dev/xvda1 ]; then
+if /usr/sbin/gptfix fix /dev/xvda; then
+    udevadm settle --exit-if-exists=/dev/xvda1
     if [ -e "/dev/disk/by-partlabel/Root\\x20filesystem" ]; then
         ROOT_DEV=$(readlink "/dev/disk/by-partlabel/Root\\x20filesystem")
         ROOT_DEV=${ROOT_DEV##*/}
     else
         ROOT_DEV=xvda3
     fi
+    if ! [ -b "/dev/$ROOT_DEV" ]; then udevadm settle "--exit-if-exists=/dev/$ROOT_DEV"; fi
 else
-    ROOT_DEV=xvda
+    status=$?
+    case $status in
+    (1|2) # EIO, ENOMEM, or bug.  Fatal.
+        die 'Fatal error reading partition table';;
+    (4|5|8) # Bad or no partition table
+        ROOT_DEV=xvda;;
+    (*)
+        # TODO: what should be done?
+        # This is things like:
+        # - "Partition table not supported"
+        die 'GPT cannot be fixed';;
+    esac
 fi
+log_end
 
 SWAP_SIZE_GiB=1
 SWAP_SIZE_512B=$(( SWAP_SIZE_GiB * 1024 * 1024 * 2 ))

dracut/simple/init.sh

@@ -28,22 +28,33 @@ die() {
 
 echo "Waiting for /dev/xvda* devices..."
 while ! [ -e /dev/xvda ]; do sleep 0.1; done
-
-# prefer partition if exists
-if [ -b /dev/xvda1 ]; then
+# Fix up partition tables
+if /usr/sbin/gptfix fix /dev/xvda; then
+    while ! [ -e /dev/xvda1 ]; do sleep 0.01; done
     if [ -d /dev/disk/by-partlabel ]; then
         ROOT_DEV=$(readlink "/dev/disk/by-partlabel/Root\\x20filesystem")
         ROOT_DEV=${ROOT_DEV##*/}
     else
-        ROOT_DEV=$(grep -l "PARTNAME=Root filesystem" /sys/block/xvda/xvda*/uevent |\
+        ROOT_DEV=$(grep -l "PARTNAME=Root filesystem" /sys/block/xvda/xvda*/uevent |
             grep -o "xvda[0-9]")
     fi
     if [ -z "$ROOT_DEV" ]; then
         # fallback to third partition
         ROOT_DEV=xvda3
     fi
+    while ! [ -b "/dev/$ROOT_DEV" ]; do sleep 0.01; done
 else
-    ROOT_DEV=xvda
+    case $? in
+    (1|2) # EIO, ENOMEM, or bug.  Fatal.
+        die 'Fatal error reading partition table';;
+    (4|5|8) # Bad or no partition table
+        ROOT_DEV=xvda;;
+    (*)
+        # TODO: what should be done?
+        # - "Partition table not supported"
+        # - "Disk truncated"
+        die 'GPT cannot be fixed or disk truncated';;
+    esac
 fi
 
 SWAP_SIZE_GiB=1

dracut/simple/module-setup.sh

@@ -29,5 +29,6 @@ install() {
         rmdir \
         sleep \
         sfdisk \
-        mkswap
+        mkswap \
+        gptfix
 }