contrib/dockerdeb

util: add utility function to skip avoiding file stat ambiguity if EPERM

Now, advancing stat.st_mtime by os.utime() is used to avoid file stat
ambiguity. But according to POSIX specification, utime(2) with an
explicit time information is permitted only for a process with:

  - the effective user ID equal to the user ID of the file, or
  - appropriate privileges

  http://pubs.opengroup.org/onlinepubs/9699919799/functions/utime.html

Therefore, just having group write access to a file causes EPERM at
applying os.utime() on it (e.g. working on the repository shared by
group access permission).

This patch adds class filestat utility function avoidamgig() to avoid
file stat ambiguity but skip it if EPERM.

It is reasonable to always ignore EPERM, because utime(2) causes EPERM
only in the case described above (EACCES is used only for utime(2)
with NULL).

#!/bin/bash -eu

. $(dirname $0)/dockerlib.sh
. $(dirname $0)/packagelib.sh

BUILDDIR=$(dirname $0)
export ROOTDIR=$(cd $BUILDDIR/.. > /dev/null; pwd)

checkdocker

DISTID="$1"
CODENAME="$2"
PLATFORM="$1-$2"
shift; shift # extra params are passed to build process

OUTPUTDIR=${OUTPUTDIR:=$ROOTDIR/packages/$PLATFORM}

initcontainer $PLATFORM

# debuild only appears to be able to save built debs etc to .., so we
# have to share the .. of the current directory with the docker
# container and hope it's writable. Whee.
dn=$(basename $PWD)

if [ $(uname) = "Darwin" ] ; then
    $DOCKER run -u $DBUILDUSER --rm -v $PWD/..:/mnt $CONTAINER \
            sh -c "cd /mnt/$dn && make clean && make local"
fi
$DOCKER run -u $DBUILDUSER --rm -v $PWD/..:/mnt $CONTAINER \
  sh -c "cd /mnt/$dn && DEB_BUILD_OPTIONS='${DEB_BUILD_OPTIONS:=}' contrib/builddeb --build --distid $DISTID --codename $CODENAME $@"
contrib/builddeb --cleanup --distid $DISTID --codename $CODENAME
if [ $(uname) = "Darwin" ] ; then
    $DOCKER run -u $DBUILDUSER --rm -v $PWD/..:/mnt $CONTAINER \
            sh -c "cd /mnt/$dn && make clean"
fi