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Filename: //usr/bin/X11/X11/mount-image-callback
#!/bin/bash VERBOSITY=0 TEMP_D="" UMOUNTS=( ) QEMU_DISCONNECT="" CR=$'\n' TAB=$'\t' error() { echo "$@" 1>&2; } Usage() { cat <<EOF Usage: ${0##*/} [ options ] file cmd [ args ] mount a file to a temporary mount point and then invoke the provided cmd with args supported 'file' are: file : any disk format supported by qemu-nbd the temporary mountpoint will be put in an a environment variable named MOUNTPOINT. if any of the arguments are the literal string '_MOUNTPOINT_', then they will be replaced with the mount point. Example: ${0##*/} my.img chroot _MOUNTPOINT_ /bin/sh Additionally, the helper program 'mchroot' will be added to the path and can be used effectively as 'chroot _MOUNTPOINT_': ${0##*/} my.img mchroot options: -v | --verbose increase verbosity -h | --help print this message. --read-only use read-only mount. -C | --cd-mountpoint change dir to mountpoint before executing cmd. -m | --mountpoint MP mount to directory MP rather than a temp dir --overlay mount via overlayfs -P | --partition PARTNUM mount partition PARTNUM (default 'auto') if 'auto', then mount part 1 if image is partitioned otherwise mount image -p | --proc bind mount /proc -s | --sys bind mount /sys -d | --dev bind mount /dev --system-mounts bind mount /sys, /proc, /dev --system-resolvconf copy host's resolvconf into /etc/resolvconf --format FMT specify the format of the image. default is to automatically determine EOF } # umount_r(mp) : unmount any filesystems under r # this is useful to unmount a chroot that had sys, proc ... mounted umount_r() { local p for p in "$@"; do [ -n "$p" ] || continue tac /proc/mounts | sh -c ' p=$1 didumount=0 while read s mp t opt a b ; do [ "${mp}" = "${p}" -o "${mp#${p}/}" != "${mp}" ] || continue umount "$mp" || exit 1 didumount=1 done [ $didumount -eq 1 ] || exit 1 exit 0' umount_r "${p%/}" [ $? -eq 0 ] || return done } bad_Usage() { Usage 1>&2; [ $# -eq 0 ] || error "$@"; exit 1; } disconnect_qemu() { [ -n "$QEMU_DISCONNECT" ] || return 0 local out="" nbd="$QEMU_DISCONNECT" debug 1 "disconnecting $nbd" local pid="" pfile="/sys/block/${nbd#/dev/}/pid" { read pid < "$pfile" ; } >/dev/null 2>&1 [ -n "$pid" -a ! -d "/proc/$pid" ] && error "qemu-nbd process seems to have died. was '$pid'" out=$(qemu-nbd --disconnect "$nbd" 2>&1) && QEMU_DISCONNECT="" || { error "failed to disconnect $nbd"; error "$out" return 1; } } do_umounts() { local um="" fails=0 mydir="$PWD/" mounts="" i=0 mounts=( "$@" ) for((i=${#mounts[@]}-1;i>=0;i--)); do um=${mounts[$i]} um=$(readlink -f "$um") || { error "WARNING: failed to get full path to '$um'"; fails=$(($fails+1)) continue; } [ "${mydir#${um}/}" != "${mydir}" ] && { error "WARNING: leaving '$mydir' to unmount $um"; cd / } umount_r "$um" || { error "WARNING: unmounting filesystem at $um failed!" fails=$(($fails+1)) } done return $fails } cleanup() { if [ "${#UMOUNTS[@]}" -ne 0 ]; then debug 2 "umounts: ${UMOUNTS[*]}" do_umounts "${UMOUNTS[@]}" fi disconnect_qemu [ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm --one-file-system -Rf "${TEMP_D}" || error "removal of temp dir failed!" } debug() { local level="$1"; shift; [ "${level}" -gt "${VERBOSITY}" ] && return error "${@}" } get_image_format() { local img="$1" out="" out=$(qemu-img info "$img") && out=$(echo "$out" | awk '$0 ~ /^file format:/ { print $3 }') && _RET="$out" } get_partition() { # return in _RET the 'auto' partition for a image. # _RET=partition number for a partitioned image # _RET=0 for unpartitioned local img="$1" out=$(LANG=C sfdisk --list -uS "$img" 2>&1) || { error "failed determining if partitioned: $out"; return 1; } if echo "$out" | grep -q 'Device.*Start.*End'; then _RET=1 else _RET=0 fi } add_bin() { cat > "$1" || { error "failed to write to $1"; return 1; } chmod 755 "$1" || { error "failed to set perms on $1"; return 1; } } add_helpers() { local d="$1" local umap="$1" gmap="$2" [ -d "$1" ] || mkdir -p "$1" add_bin "$d/mchroot" <<"EOF" || return 1 #!/bin/sh exec chroot "$MOUNTPOINT" "$@" EOF return } mount_overlay() { local lower="$1" upper="$2" workdir="$3" local olayopts="lowerdir=$lower,upperdir=$upper" # 3.18+ require 'workdir=' option. case "$(uname -r)" in 2*|3.1[01234567]*|3.[0-9].*) :;; *) olayopts="${olayopts},workdir=$workdir" mkdir -p "$workdir" || { _ERR="Failed to create workdir '$workdir'"; return 1; } ;; esac local cmd="" fstype="" ret="" out="" fsfile="/proc/filesystems" _ERR="" for fstype in overlay overlayfs; do cmd=( mount -t "$fstype" -o "$olayopts" "$lower" "$upper" ) debug 2 "attempting '$fstype' mount with: ${cmd[*]}" out=$("${cmd[@]}" 2>&1) ret=$? if [ $ret -eq 0 ]; then debug 1 "mounted '$fstype' via $fstype: ${cmd[*]}" return 0 fi _ERR="${_ERR}Failed [$ret]: ${cmd[*]}:${CR}" _ERR="${_ERR}$out${CR}" if [ -r "$fsfile" ] && grep -q "${TAB}${fstype}$" "$fsfile"; then # this failed and we have support in kernel. do not try further. return $ret fi done return $ret } assert_nbd_support() { if [ ! -e /sys/block/nbd0 ] && ! grep -q nbd /proc/modules; then debug 1 "trying to load nbd module" modprobe nbd >/dev/null 2>&1 udevadm settle >/dev/null 2>&1 fi [ -e /sys/block/nbd0 ] || { error "Cannot use nbd: no nbd kernel support." return 1; } } find_unused_nbd() { # return a path to an unused nbd device (/dev/nbd?) local f roflag="" for f in /sys/block/nbd*; do [ -d "$f" -a ! -f "$f/pid" ] && { _RET="/dev/${f##*/}"; return 0; } done error "failed to find an nbd device" return 1; } connect_nbd() { local img="$1" fmt="$2" ptnum="${3:-auto}" rwmode="${3:-ro}" local nbd="" pidfile="" pid="" cmd="" ret="" roflag="" nptnum="" i="" if [ "$rwmode" = "ro" ]; then roflag="--read-only" fi # yes, there is a race condition here. find_unused_nbd || return nbd="$_RET" cmd=( qemu-nbd $roflag "--format=$fmt" --connect "$nbd" "$img" ) "${cmd[@]}" && QEMU_DISCONNECT="$nbd" ret=$? if [ $ret -ne 0 ]; then error "Failed [$ret]: $*" return $ret fi pidfile="/sys/block/${nbd#/dev/}/pid" if [ ! -f "$pidfile" ]; then debug 1 "waiting on pidfile for $nbd in $pidfile" i=0 while [ ! -f "$pidfile" ] && i=$(($i+1)); do if [ $i -eq 200 ]; then error "giving up on pidfile $pidfile for $nbd" disconnect_qemu return 1 fi sleep .1 debug 2 "." done fi read pid < "$pidfile" && debug 2 "pid for $nbd is $pid" || { error "reading pid from $pidfile for $nbd failed!"; disconnect_qemu return 1 } debug 1 "connected $img_in ($fmt) ${rwmode} to $nbd. waiting for device." local out="" # This can fail due to udev events, but we ignore that. We need to ensure # it happens for where it doesnt happen automatically (LP: #1741300) out=$(blockdev --rereadpt "$nbd" 2>&1) || debug 1 "blockdev rereadpt $nbd failed" udevadm settle i=0 while i=$(($i+1)); do get_partition "$nbd" && nptnum="$_RET" && break [ $i -eq 40 ] && { error "gave up on $nbd" disconnect_qemu return 1 } [ $(($i%10)) -eq 0 ] && debug 1 "waiting for $nbd to be ready." sleep .1 done if [ "${ptnum}" = "auto" ]; then if [ "$nptnum" = "0" ]; then debug 1 "unpartitioned disk." else debug 1 "partitioned disk." fi ptnum=$nptnum else if [ "$nptnum" = "0" -a "$ptnum" != "0" ]; then error "img $img does not appear partitioned but ptnum=$ptnum provided." return 1 fi fi if [ "$ptnum" -ne 0 ]; then mdev="${nbd}p${ptnum}" else mdev="${nbd}" fi i=0 while :; do [ -b "$mdev" ] && break i=$(($i+1)) [ $i -eq 100 ] && { error "gave up on waiting for $mdev" disconnect_qemu return 1 } [ $(($i%10)) -eq 0 ] && debug 1 "waiting for $mdev part=$ptnum to be ready." sleep .1 done _RET_NBD="$nbd" _RET_PT="$ptnum" _RET_DEV="$mdev" } mount_nbd() { local img="$1" mp="$2" fmt="$3" ptnum="$4" rwmode="${5:-rw}" opts="$6" if [ -z "$fmt" ]; then get_image_format "$img" && fmt="$_RET" || { error "failed to get image format for '$img' (try --format)" return 1 } fi assert_nbd_support || return connect_nbd "$img" "$fmt" "$ptnum" "$rwmode" || return local ptnum="$_RET_PT" mdev="$_RET_DEV" nbd="$_RET_NBD" if ( set -f; mount -o "$rwmode" $opts "$mdev" "$img_mp" ); then debug 1 "mounted $mdev via qemu-nbd $nbd at $img_mp" else error "failed to mount $mdev" return 1 fi } mount_callback_umount() { local img_in="$1" dev="" out="" mp="" ret="" img="" readonly=false local opts="" bmounts="" system_resolvconf=false ptnum=auto local cd_mountpoint=false fmt="" overlay=false rwmode="rw" local img_mp="" short_opts="Cdhm:P:psSv" long_opts="cd-mountpoint,dev,help,format:,mountpoint:,overlay,partition:,proc,read-only,sys,system-mounts,system-resolvconf,verbose" getopt_out=$(getopt --name "${0##*/}" \ --options "${short_opts}" --long "${long_opts}" -- "$@") && eval set -- "${getopt_out}" || { bad_Usage; return 1; } while [ $# -ne 0 ]; do cur=${1}; next=${2}; case "$cur" in -C|--cd-mountpoint) cd_mountpoint=true;; -d|--dev) bmounts="${bmounts:+${bmounts} }/dev";; --format) fmt=$next;; -h|--help) Usage ; exit 0;; -m|--mountpoint) mp=$next;; -P|--partition) ptnum=$next;; --overlay) overlay=true;; -p|--proc) bmounts="${bmounts:+${bmounts} }/proc";; -s|--sys) bmounts="${bmounts:+${bmounts} }/sys";; -S|--system-mounts) bmounts="/dev /proc /sys";; --system-resolvconf) system_resolvconf=true;; -v|--verbose) VERBOSITY=$((${VERBOSITY}+1));; --opts) opts="${opts} $next"; shift;; --read-only) readonly=true; rwmode="ro";; --) shift; break;; esac shift; done [ $# -ge 2 ] || { bad_Usage "must provide image and cmd"; return 1; } $readonly && { $system_resolvconf && ! $overlay; } && { error "--read-only is incompatible with system-resolvconf"; error "maybe try with --overlay" return 1; } img_in="$1" shift 1 if [ "${img_in#lxd:}" != "${img_in}" -a ! -f "${img_in}" ]; then error "${img_in}: lxd is no longer supported." return 1; fi img=$(readlink -f "$img_in") || { error "failed to get full path to $img_in"; return 1; } [ -f "$img" ] || { error "$img: not a file"; return 1; } [ "$(id -u)" = "0" ] || { error "sorry, must be root"; return 1; } trap cleanup EXIT TEMP_D=$(mktemp -d "${TMPDIR:-/tmp}/${0##*/}.XXXXXX") || { error "failed to make tempdir"; return 1; } if [ -z "$mp" ]; then mp="${TEMP_D}/mp" mkdir "$mp" || return else [ -d "$mp" ] || { error "mountpoint '$mp': not a directory"; return 1; } mp=$(readlink -f "$mp") || { error "failed to get full path to provided mountpoint"; return 1; } fi if $overlay; then img_mp="${TEMP_D}/underlay" mkdir -p "$img_mp" || return else img_mp=$mp fi out="" if [ "$ptnum" = "auto" -o "$ptnum" = "0" ] && out=$(set -f; mount -o "loop,$rwmode" $opts "$img" "$img_mp" 2>&1); then debug 1 "mounted simple fs image $rwmode in '$img_in' at $img_mp" UMOUNTS[${#UMOUNTS[@]}]="$img_mp" else local hasqemu=false command -v "qemu-nbd" >/dev/null 2>&1 && hasqemu=true if ! $hasqemu; then error "simple mount of '$img_in' failed." error "if this is not a simple unpartitioned raw image, then" error "you must have qemu-nbd (apt-get install qemu-utils)" if [ -n "$out" ]; then error "mount failed with: $out" fi return 1 fi mount_nbd "$img" "$img_mp" "$fmt" "$ptnum" "$rwmode" "$opts" || return UMOUNTS[${#UMOUNTS[@]}]="$img_mp" fi if $overlay; then mount_overlay "$img_mp" "$mp" "${TEMP_D}/workdir" || { [ -n "${_ERR}" ] && error "${_ERR}" error "Unable to mount overlay filesystem. Maybe no kernel support?" return 1 } UMOUNTS[${#UMOUNTS[@]}]="$mp" fi local bindmp="" for bindmp in $bmounts; do [ -d "$mp${bindmp}" ] || mkdir "$mp${bindmp}" || { error "failed mkdir $bindmp in mount"; return 1; } mount --bind "$bindmp" "$mp${bindmp}" || { error "failed bind mount '$bindmp'"; return 1; } UMOUNTS[${#UMOUNTS[@]}]="$mp${bindmp}" debug 1 "mounted $bindmp to $mp${bindmp}" done if ${system_resolvconf}; then local rcf="$mp/etc/resolv.conf" debug 1 "replacing /etc/resolvconf" if [ -e "$rcf" -o -L "$rcf" ]; then local trcf="$rcf.${0##*/}.$$" rm -f "$trcf" && mv "$rcf" "$trcf" && ORIG_RESOLVCONF="$trcf" || { error "failed mv $rcf"; return 1; } fi cp "/etc/resolv.conf" "$rcf" || { error "failed copy /etc/resolv.conf"; return 1; } fi local cmd="" arg="" found=false cmd=( ) for arg in "$@"; do if [ "${arg}" = "_MOUNTPOINT_" ]; then debug 1 "replaced string _MOUNTPOINT_ in arguments arg ${#cmd[@]}" arg=$mp fi cmd[${#cmd[@]}]="$arg" done if [ "${cmd[0]##*/}" = "bash" -o "${cmd[0]##*/}" = "sh" ] && [ ${#cmd[@]} -eq 0 ]; then debug 1 "invoking shell ${cmd[0]}" error "MOUNTPOINT=$mp" fi add_helpers "$TEMP_D/bin" "$SUBUID" "$SUBGID" || { error "failed to add helpers to $TEMP_D"; return 1; } PATH="$TEMP_D/bin:$PATH" local startwd="$PWD" debug 1 "invoking: MOUNTPOINT=$mp" "${cmd[@]}" ${cd_mountpoint} && cd "$mp" MOUNTPOINT="$mp" "${cmd[@]}" ret=$? cd "$startwd" if ${system_resolvconf}; then local rcf="$mp/etc/resolv.conf" cmp --quiet "/etc/resolv.conf" "$rcf" >/dev/null || error "WARN: /etc/resolv.conf changed in image!" rm "$rcf" && { [ -z "$ORIG_RESOLVCONF" ] || mv "$ORIG_RESOLVCONF" "$rcf"; } || { error "failed to restore /etc/resolv.conf"; return 1; } fi debug 1 "cmd returned $ret. unmounting $mp" do_umounts "${UMOUNTS[@]}" && UMOUNTS=( ) || { error "failed umount $img"; return 1; } if [ -n "$QEMU_DISCONNECT" ]; then disconnect_qemu || return 1; fi return $ret } mount_callback_umount "$@" # vi: ts=4 noexpandtab
./Ninja\.