Re: [PATCH] isar: Clean mount point on bitbake exit

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2018-02-06 20:55, Alexander Smirnov wrote:
> 8<--
> 
> That's it! Branch 'asmirnov/devel', please test and enjoy :-)
> 
> 8<--
> 
> Now each multiconfig has registered handler for BuildCompleted event (see
> class 'isar-event.bbclass'). Moreover, the '/proc/mounts' file contains
> all the active mounts. In addition, from event handler we could derive
> all the variables like ${TMPDIR}, ${DISTRO} etc. So it's possible to
> find all the active mounts for current multiconfig and clean them.
> 
> NOTE: if build is interrupted by double ^C, some mount points could stay
> uncleaned. This is caused by remaining processes started by bitbake, for
> example:
>  - 'chroot build.sh ...'
>  - 'multistrap ...'

Can you explain what the race condition is exactly? It seems to work for
me so far, no forgotten mounts.

Jan

> 
> So please be careful when interrupting build.
> 
> Signed-off-by: Alexander Smirnov <asmirnov@ilbers.de>
> ---
>  meta-isar/recipes-core/images/isar-image-base.bb   | 11 ++++------
>  meta/classes/dpkg-base.bbclass                     | 12 ++++-------
>  meta/classes/isar-events.bbclass                   | 15 +++++++++++---
>  meta/recipes-devtools/buildchroot/buildchroot.bb   | 24 +++++++++-------------
>  .../buildchroot/files/configscript.sh              |  4 ----
>  .../buildchroot/files/download_dev-random          | 13 ------------
>  6 files changed, 30 insertions(+), 49 deletions(-)
>  delete mode 100644 meta/recipes-devtools/buildchroot/files/download_dev-random
> 
> diff --git a/meta-isar/recipes-core/images/isar-image-base.bb b/meta-isar/recipes-core/images/isar-image-base.bb
> index e359ac3..8ddbabb 100644
> --- a/meta-isar/recipes-core/images/isar-image-base.bb
> +++ b/meta-isar/recipes-core/images/isar-image-base.bb
> @@ -55,14 +55,10 @@ do_rootfs() {
>          -e 's|##ISAR_DISTRO_SUITE##|${DEBDISTRONAME}|g' \
>             "${WORKDIR}/multistrap.conf.in" > "${WORKDIR}/multistrap.conf"
>  
> +    # Do not use bitbake flag [dirs] here because this folder should have
> +    # specific ownership.
>      [ ! -d ${IMAGE_ROOTFS}/proc ] && sudo install -d -o 0 -g 0 -m 555 ${IMAGE_ROOTFS}/proc
>      sudo mount -t proc none ${IMAGE_ROOTFS}/proc
> -    _do_rootfs_cleanup() {
> -        ret=$?
> -        sudo umount ${IMAGE_ROOTFS}/proc 2>/dev/null || true
> -        (exit $ret) || bb_exit_handler
> -    }
> -    trap '_do_rootfs_cleanup' EXIT
>  
>      # Create root filesystem. We must use sudo -E here to preserve the environment
>      # because of proxy settings
> @@ -72,5 +68,6 @@ do_rootfs() {
>      sudo chroot ${IMAGE_ROOTFS} /${DISTRO_CONFIG_SCRIPT} ${MACHINE_SERIAL} ${BAUDRATE_TTY} \
>          ${ROOTFS_DEV}
>      sudo rm "${IMAGE_ROOTFS}/${DISTRO_CONFIG_SCRIPT}"
> -    _do_rootfs_cleanup
> +
> +    sudo umount ${IMAGE_ROOTFS}/proc 2>/dev/null || true
>  }
> diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-base.bbclass
> index 5d5a924..a34c21f 100644
> --- a/meta/classes/dpkg-base.bbclass
> +++ b/meta/classes/dpkg-base.bbclass
> @@ -20,15 +20,11 @@ dpkg_runbuild() {
>  do_build() {
>      mkdir -p ${BUILDROOT}
>      sudo mount --bind ${WORKDIR} ${BUILDROOT}
> -    _do_build_cleanup() {
> -        ret=$?
> -        sudo umount ${BUILDROOT} 2>/dev/null || true
> -        sudo rmdir ${BUILDROOT} 2>/dev/null || true
> -        (exit $ret) || bb_exit_handler
> -    }
> -    trap '_do_build_cleanup' EXIT
> +
>      dpkg_runbuild
> -    _do_build_cleanup
> +
> +    sudo umount ${BUILDROOT} 2>/dev/null || true
> +    sudo rmdir ${BUILDROOT} 2>/dev/null || true
>  }
>  
>  # Install package to Isar-apt
> diff --git a/meta/classes/isar-events.bbclass b/meta/classes/isar-events.bbclass
> index 55fc106..ae0f791 100644
> --- a/meta/classes/isar-events.bbclass
> +++ b/meta/classes/isar-events.bbclass
> @@ -11,10 +11,19 @@ python isar_handler () {
>      devnull = open(os.devnull, 'w')
>  
>      if isinstance(e, bb.event.BuildCompleted):
> -        bchroot = d.getVar('BUILDCHROOT_DIR', True)
> +        tmpdir = d.getVar('TMPDIR', True)
> +        distro = d.getVar('DISTRO', True)
> +        arch = d.getVar('DISTRO_ARCH', True)
>  
> -        # Clean up buildchroot
> -        subprocess.call('/usr/bin/sudo /bin/umount ' + bchroot + '/isar-apt || /bin/true', stdout=devnull, stderr=devnull, shell=True)
> +        w = tmpdir + '/work/' + distro + '-' + arch
> +
> +        # '/proc/mounts' contains all the active mounts, so knowing 'w' we
> +        # could get the list of mounts for the specific multiconfig and
> +        # clean them.
> +        with open('/proc/mounts', 'rU') as f:
> +            for line in f:
> +                if w in line:
> +                    subprocess.call('sudo umount -f ' + line.split()[1], stdout=devnull, stderr=devnull, shell=True)
>  
>      devnull.close()
>  }
> diff --git a/meta/recipes-devtools/buildchroot/buildchroot.bb b/meta/recipes-devtools/buildchroot/buildchroot.bb
> index 304c67e..df9df19 100644
> --- a/meta/recipes-devtools/buildchroot/buildchroot.bb
> +++ b/meta/recipes-devtools/buildchroot/buildchroot.bb
> @@ -12,7 +12,6 @@ FILESPATH =. "${LAYERDIR_core}/recipes-devtools/buildchroot/files:"
>  SRC_URI = "file://multistrap.conf.in \
>             file://configscript.sh \
>             file://setup.sh \
> -           file://download_dev-random \
>             file://build.sh"
>  PV = "1.0"
>  
> @@ -32,8 +31,10 @@ BUILDCHROOT_PREINSTALL ?= "gcc \
>  WORKDIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/${PN}"
>  
>  do_build[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
> -do_build[dirs] = "${WORKDIR}/hooks_multistrap \
> -                  ${BUILDCHROOT_DIR}/isar-apt"
> +do_build[dirs] = "${BUILDCHROOT_DIR}/isar-apt \
> +                  ${BUILDCHROOT_DIR}/dev \
> +                  ${BUILDCHROOT_DIR}/proc \
> +                  ${BUILDCHROOT_DIR}/sys"
>  do_build[depends] = "isar-apt:do_cache_config"
>  
>  do_build() {
> @@ -41,7 +42,6 @@ do_build() {
>  
>      chmod +x "${WORKDIR}/setup.sh"
>      chmod +x "${WORKDIR}/configscript.sh"
> -    install -m 755 "${WORKDIR}/download_dev-random" "${WORKDIR}/hooks_multistrap/"
>  
>      # Multistrap accepts only relative path in configuration files, so get it:
>      cd ${TOPDIR}
> @@ -60,15 +60,6 @@ do_build() {
>          -e 's|##DIR_HOOKS##|./'"$WORKDIR_REL"'/hooks_multistrap|g' \
>             "${WORKDIR}/multistrap.conf.in" > "${WORKDIR}/multistrap.conf"
>  
> -    [ ! -d ${BUILDCHROOT_DIR}/proc ] && install -d -m 555 ${BUILDCHROOT_DIR}/proc
> -    sudo mount -t proc none ${BUILDCHROOT_DIR}/proc
> -    _do_build_cleanup() {
> -        ret=$?
> -        sudo umount ${BUILDCHROOT_DIR}/proc 2>/dev/null || true
> -        (exit $ret) || bb_exit_handler
> -    }
> -    trap '_do_build_cleanup' EXIT
> -
>      do_setup_mounts
>  
>      # Create root filesystem
> @@ -79,7 +70,6 @@ do_build() {
>  
>      # Configure root filesystem
>      sudo chroot ${BUILDCHROOT_DIR} /configscript.sh
> -    _do_build_cleanup
>  
>      do_cleanup_mounts
>  }
> @@ -96,10 +86,16 @@ do_setup_mounts[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
>  
>  do_setup_mounts() {
>      sudo mount --bind ${DEPLOY_DIR_APT}/${DISTRO} ${BUILDCHROOT_DIR}/isar-apt
> +    sudo mount --bind /dev ${BUILDCHROOT_DIR}/dev
> +    sudo mount -t proc none ${BUILDCHROOT_DIR}/proc
> +    sudo mount -t sysfs none ${BUILDCHROOT_DIR}/sys
>  }
>  
>  addtask setup_mounts after do_build
>  
>  do_cleanup_mounts() {
>      sudo umount ${BUILDCHROOT_DIR}/isar-apt 2>/dev/null || true
> +    sudo umount ${BUILDCHROOT_DIR}/dev 2>/dev/null || true
> +    sudo umount ${BUILDCHROOT_DIR}/proc 2>/dev/null || true
> +    sudo umount ${BUILDCHROOT_DIR}/sys 2>/dev/null || true
>  }
> diff --git a/meta/recipes-devtools/buildchroot/files/configscript.sh b/meta/recipes-devtools/buildchroot/files/configscript.sh
> index 9813c9a..524e50c 100644
> --- a/meta/recipes-devtools/buildchroot/files/configscript.sh
> +++ b/meta/recipes-devtools/buildchroot/files/configscript.sh
> @@ -39,10 +39,6 @@ export LC_ALL=C LANGUAGE=C LANG=C
>  #run pre installation script
>  /var/lib/dpkg/info/dash.preinst install
>  
> -# apt-get http method, gpg require /dev/null
> -mount -t devtmpfs -o mode=0755,nosuid devtmpfs /dev
> -
>  #configuring packages
>  dpkg --configure -a
>  apt-get update
> -umount /dev
> diff --git a/meta/recipes-devtools/buildchroot/files/download_dev-random b/meta/recipes-devtools/buildchroot/files/download_dev-random
> deleted file mode 100644
> index 5b5b96b..0000000
> --- a/meta/recipes-devtools/buildchroot/files/download_dev-random
> +++ /dev/null
> @@ -1,13 +0,0 @@
> -#!/bin/sh
> -
> -set -e
> -
> -readonly ROOTFS="$1"
> -
> -mknod "${ROOTFS}/dev/random" c 1 8
> -chmod 640 "${ROOTFS}/dev/random"
> -chown 0:0 "${ROOTFS}/dev/random"
> -
> -mknod "${ROOTFS}/dev/urandom" c 1 9
> -chmod 640 "${ROOTFS}/dev/urandom"
> -chown 0:0 "${ROOTFS}/dev/urandom"
>