From aece2dad3e16feb6073e17a3b61dfd8d69007ecb Mon Sep 17 00:00:00 2001
From: Helmut Grohne <helmut@subdivi.de>
Date: Wed, 11 Jan 2023 19:25:08 +0100
Subject: move the debvm-* tools to bin
The purpose of this change is adding support files to be referenced and
called from these tools. Those support files shall be located in
../share and this way of locating them shall work both in-source and
when installed.
---
bin/debvm-run | 272 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 272 insertions(+)
create mode 100755 bin/debvm-run
(limited to 'bin/debvm-run')
diff --git a/bin/debvm-run b/bin/debvm-run
new file mode 100755
index 0000000..c2a3f21
--- /dev/null
+++ b/bin/debvm-run
@@ -0,0 +1,272 @@
+#!/bin/sh
+# Copyright 2022 Helmut Grohne <helmut@subdivi.de>
+# SPDX-License-Identifier: MIT
+
+: <<'POD2MAN'
+=head1 NAME
+
+debvm-run - Run a VM image created by debvm-create
+
+=head1 SYNOPSIS
+
+B<debvm-run> [B<-g>] [B<-i> F<image>] [B<-s> I<sshport>] [B<--> I<qemu options>]
+
+=head1 DESCRIPTION
+
+B<debvm-run> is essentially a thin wrapper around B<qemu> for running a virtual machine image created by B<debvm-create> or something compatible.
+The virtual machine image is expected to be a raw ext4 image with file system label B<debvm>.
+The architecture of the machine is detected from the contained F</bin/true>.
+It must contain a symbolic link pointing to a kernel image at F</vmlinuz> or F</vmlinux> depending on the architecture and a symbolic link pointing to an initrd image at F</initrd.img>.
+Both are extracted and passed to B<qemu>.
+A net interface configured for user mode is added automatically.
+
+=head1 OPTIONS
+
+=over 8
+
+=item B<-g>, B<--graphical>
+
+By default, the option B<-nographic> is passed to B<qemu> and one interacts with the serial console of the machine.
+This configuration is skipped in the presence of this option.
+
+=item B<-i> F<image>, B<--image>=F<image>
+
+This option specifies the location of the virtual machine image file.
+By default F<rootfs.ext4> in the working directory is used.
+
+=item B<-s> I<sshport>, B<--sshport>=I<sshport>
+
+If given, B<qemu> is configured to pass connections to I<127.0.0.1:sshport> to port 22 of the virtual machine.
+You can connect to your virtual machine without updating your known hosts like this:
+
+ ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p $sshport root@127.0.0.1
+
+=item B<--> I<qemu options>
+
+All options beyond a double dash are passed to B<qemu>.
+This can be used to configure additional hardware components.
+One possible use of this method is passing B<-snapshot> to avoid modifying the virtual machine image.
+
+=back
+
+=head1 EXAMPLES
+
+Run a virtual machine stored in the image F<rootfs.ext4> (the default) with
+local port 8022 routed to port 22 of the virtual machine. The B<-snapshot>
+argument is passed to QEMU and prevents any permanent changes to
+F<rootfs.ext4>, resulting in an ephemeral run.
+
+ debvm-run -s 8022 -i rootfs.ext4 -- -snapshot
+
+=head1 LIMITATIONS
+
+Due to the way kernel and bootloader are being extracted before running B<qemu>, one cannot upgrade a kernel and then just reboot.
+Attempting to do so, will still use the old kernel.
+Instead, B<qemu> must be terminated and B<debvm-run> should be launched again to pick up the new kernel.
+In order to avoid accidental reboots, one may pass B<-no-reboot> to B<qemu>.
+
+=head1 SEE ALSO
+
+ debvm-create(1) qemu(1)
+
+=cut
+POD2MAN
+
+set -u
+
+IMAGE=rootfs.ext4
+SSHPORT=
+GRAPHICAL=
+
+nth_arg() {
+ shift "$1"
+ printf "%s" "$1"
+}
+
+die() {
+ echo "$*" 1>&2
+ exit 1
+}
+usage() {
+ die "usage: $0 [-g] [-i image] [-s sshport] [-- qemu options]"
+}
+usage_error() {
+ echo "error: $*" 1>&2
+ usage
+}
+
+opt_graphical() {
+ GRAPHICAL=1
+}
+opt_image() {
+ IMAGE=$1
+}
+opt_sshport() {
+ SSHPORT=$1
+}
+
+while getopts :gi:s:-: OPTCHAR; do
+ case "$OPTCHAR" in
+ g) opt_graphical ;;
+ i) opt_image "$OPTARG" ;;
+ s) opt_sshport "$OPTARG" ;;
+ -)
+ case "$OPTARG" in
+ help)
+ usage
+ ;;
+ graphical|image|sshport)
+ test "$OPTIND" -gt "$#" && usage_error "missing argument for --$OPTARG"
+ "opt_$OPTARG" "$(nth_arg "$OPTIND" "$@")"
+ OPTIND=$((OPTIND+1))
+ ;;
+ image=*|sshport=*)
+ "opt_${OPTARG%%=*}" "${OPTARG#*=}"
+ ;;
+ *)
+ usage_error "unrecognized option --$OPTARG"
+ ;;
+ esac
+ ;;
+ :)
+ usage_error "missing argument for -$OPTARG"
+ ;;
+ '?')
+ usage_erro "unrecognized option -$OPTARG"
+ ;;
+ *)
+ die "internal error while parsing command options, please report a bug"
+ ;;
+ esac
+done
+shift "$((OPTIND - 1))"
+
+test -f "$IMAGE" || die "image '$IMAGE' not found"
+test -s "$IMAGE" || die "image '$IMAGE' is empty"
+
+if ! printf '\123\357' | cmp --bytes=2 "$IMAGE" - 1080; then
+ die "image '$IMAGE' is not in ext4 format"
+fi
+
+if ! printf 'debvm\000' | cmp --bytes=6 "$IMAGE" - 1144; then
+ die "image '$IMAGE' was not created by debvm-create (wrong disk label)"
+fi
+
+cleanup() {
+ set +x
+ test -n "$KERNELTMP" && rm -f "$KERNELTMP"
+ test -n "$INITRDTMP" && rm -f "$INITRDTMP"
+}
+
+trap cleanup EXIT INT TERM QUIT
+
+KERNELTMP=$(mktemp)
+INITRDTMP=$(mktemp)
+
+ARCHITECTURE=$(dpkg --print-architecture)
+VMARCH=$ARCHITECTURE
+if command -v elf-arch >/dev/null 2>&1; then
+ /sbin/debugfs "$IMAGE" -R "cat /bin/true" > "$KERNELTMP"
+ VMARCH=$(elf-arch "$KERNELTMP")
+fi
+case "$VMARCH" in
+ mips*|ppc64el)
+ KERNELLINK=vmlinux
+ ;;
+ *)
+ KERNELLINK=vmlinuz
+ ;;
+esac
+
+KERNELNAME=$(/sbin/debugfs "$IMAGE" -R "stat $KERNELLINK" | sed 's/Fast link dest: "\(.*\)"/\1/;t;d')
+INITRDNAME=$(/sbin/debugfs "$IMAGE" -R "stat initrd.img" | sed 's/Fast link dest: "\(.*\)"/\1/;t;d')
+
+test -n "$KERNELNAME" || die "failed to discover kernel image"
+test -n "$INITRDNAME" || die "failed to discover initrd image"
+
+KERNEL_CMDLINE="root=LABEL=debvm rw"
+NETDEV="user,id=net0"
+
+set -- \
+ -no-user-config \
+ -name "debvm-run $IMAGE" \
+ -m 1G \
+ -kernel "$KERNELTMP" \
+ -initrd "$INITRDTMP" \
+ -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-pci,rng=rng0 \
+ -drive "media=disk,format=raw,discard=unmap,file=$IMAGE,if=virtio,cache=unsafe" \
+ -device "virtio-net-pci,netdev=net0" \
+ "$@"
+
+MAX_SMP=
+if test "$ARCHITECTURE" = "$VMARCH"; then
+ QEMU=kvm
+ # While kvm will fall back gracefully, the following options can only
+ # be passed when kvm really is available.
+ if test -w /dev/kvm; then
+ set -- -enable-kvm -cpu host "$@"
+ fi
+ case "$VMARCH" in
+ arm64)
+ set -- -machine type=virt,gic-version=host "$@"
+ ;;
+ esac
+else
+ QEMU="qemu-system-$VMARCH"
+ case "$VMARCH" in
+ arm64)
+ QEMU=qemu-system-aarch64
+ set -- -machine virt -cpu max "$@"
+ ;;
+ arm|armel|armhf)
+ QEMU=qemu-system-arm
+ set -- -machine virt -cpu max "$@"
+ ;;
+ ppc64el)
+ QEMU=qemu-system-ppc64
+ ;;
+ mips64el)
+ MAX_SMP=1
+ set -- -cpu 5KEc "$@"
+ ;;
+ mipsel)
+ MAX_SMP=1
+ ;;
+ riscv64)
+ set -- -machine virt "$@"
+ ;;
+ esac
+fi
+if test -z "$MAX_SMP" || test "$MAX_SMP" -gt 1; then
+ NPROC=$(nproc)
+ test -n "$MAX_SMP" && test "$NPROC" -gt "$MAX_SMP" && NPROC=$MAX_SMP
+ set -- -smp "$NPROC" "$@"
+fi
+
+if test -z "$GRAPHICAL"; then
+ set -- -nographic "$@"
+ case "$VMARCH" in
+ amd64|i386)
+ KERNEL_CMDLINE="$KERNEL_CMDLINE console=ttyS0"
+ ;;
+ esac
+fi
+
+if test -n "$SSHPORT"; then
+ NETDEV="$NETDEV,hostfwd=tcp:127.0.0.1:$SSHPORT-:22"
+fi
+DNSSEARCH=$(dnsdomainname)
+if test -n "$DNSSEARCH"; then
+ NETDEV="$NETDEV,domainname=$DNSSEARCH"
+fi
+set -- \
+ -append "$KERNEL_CMDLINE" \
+ -netdev "$NETDEV" \
+ "$@"
+
+set -ex
+
+/sbin/debugfs "$IMAGE" -R "cat $KERNELNAME" > "$KERNELTMP"
+/sbin/debugfs "$IMAGE" -R "cat $INITRDNAME" > "$INITRDTMP"
+
+"$QEMU" "$@"
--
cgit v1.2.3