mountrepo

#!/bin/bash
#
# Mount a cvmfs repository as an unprivileged user.
# Works with fusermount or with a kernel (>= 4.18) that supports mounting
#   fuse repositories in unprivileged "fakeroot" namespaces.
# Mounts in cvmfs subdirectory of the directory where the command is found.
# Written by Dave Dykstra 17 April 2019
#

usage()
{
    echo "Usage: mountrepo repo.name" >&2
    exit 1
}

if [ $# != 1 ]; then
    usage
fi

REPO="$1"

if [ -n "$CVMFSEXEC_CMDFD" ] && [ -n "$CVMFSEXEC_WAITFIFO" ]; then
    # this is within cvmfsexec, requesting to mount another repo
    if [ -z "$CVMFSMOUNT" ]; then
        echo "$0: mount within cvmfsexec only works through \$CVMFSMOUNT interface" >&2
        exit 1
    fi

    # Send command to the "parent" process still outside the namespace.
    # "Parent" is in quotes because the linux process tree gets reversed and
    #   it is actually a linux child.  It is a parent environment-wise though.
    set -e
    echo MOUNTREPO $REPO >&$CVMFSEXEC_CMDFD
    exec {CVMFSEXEC_CMDFD}>&- # close it, no longer needed
    # wait until that process is finished mounting
    read RET <$CVMFSEXEC_WAITFIFO
    exit $RET
fi

HERE="$(cd `dirname $0` && pwd)"
DIST="$HERE/dist"

if [ ! -f $DIST/usr/bin/cvmfs2 ] || [ ! -f $DIST/etc/cvmfs/default.conf ]; then
    echo "$DIST should be rpm2cpio of cvmfs rpm" >&2
    exit 1
fi

CONFFILE="`mktemp`"
trap "rm -f $CONFFILE" 0

# recursively substitute a ". " or "source " with the contents of the
#  sourced file. 
procsource()
{
    for FILE; do
        while read LINE; do
            case "$LINE" in
                ". "*) eval procsource "${LINE/. /}";;
                "source "*) eval procsource "${LINE/source /}";;
                *) echo "$LINE";;
            esac
        done <$FILE
    done
}

# relocate the given files and process them for sourced files the same way
#  that cvmfs does
relocate()
{
    cd ${1%/*}
    # do /var first in case $DIST begins with /var
    procsource $* 2>/dev/null | \
        sed -e "s,^\([^/]*\)/var,\1$DIST/var," \
            -e "s,^\([^/]*\)/etc,\1$DIST/etc," \
            -e "s,^\([^/]*\)/cvmfs$,\1$DIST/cvmfs," \
            -e "s,^\([^/]*\)/cvmfs/,\1$DIST/cvmfs/,"
    cd - >/dev/null
}

DOMAIN="`echo "$REPO"|cut -d. -f2-`"
(
DEFD_FILES="`find $DIST/etc/cvmfs/default.d -name "*.conf" 2>/dev/null`"
if [ -n "$DEFD_FILES" ]; then
    CONFIG_REPO="`sed -n 's/^CVMFS_CONFIG_REPOSITORY=//p' $DIST/etc/cvmfs/default.d/*.conf`"
fi
# these are used in some configuration repository includes, set them
#   for procsource
CVMFS_CONFIG_REPOSITORY=$CONFIG_REPO
CVMFS_MOUNT_DIR=$DIST/cvmfs

relocate $DIST/etc/cvmfs/default.conf
if [ -n "$DEFD_FILES" ]; then
    relocate $DIST/etc/cvmfs/default.d/*.conf
fi
if [ -n "$CONFIG_REPO" -a "$REPO" != "$CONFIG_REPO" ]; then
    relocate $DIST/cvmfs/$CONFIG_REPO/etc/cvmfs/default.conf
fi

DEFLOCAL=$DIST/etc/cvmfs/default.local
relocate $DEFLOCAL
# set some defaults if they weren't already in the dist's default.local
if ! grep -q "^CVMFS_NFILES=" $DEFLOCAL 2>/dev/null; then
    echo "CVMFS_NFILES=`ulimit -Hn`"
fi
if ! grep -q "^CVMFS_USYSLOG=" $DEFLOCAL 2>/dev/null; then
    mkdir -p $HERE/log
    echo "CVMFS_USYSLOG=$HERE/log/$REPO.log"
fi
if ! grep -q "^CVMFS_CACHE_BASE=" $DEFLOCAL 2>/dev/null && [ -d /e2fs ]; then
    mkdir -p /e2fs/cvmfscache
    echo "CVMFS_CACHE_BASE=/e2fs/cvmfscache"
fi

if [ -n "$CONFIG_REPO" -a "$REPO" != "$CONFIG_REPO" ]; then
    relocate $DIST/cvmfs/$CONFIG_REPO/etc/cvmfs/domain.d/$DOMAIN.conf
fi
relocate $DIST/etc/cvmfs/domain.d/$DOMAIN.conf
relocate $DIST/etc/cvmfs/domain.d/$DOMAIN.local
if [ -n "$CONFIG_REPO" -a "$REPO" != "$CONFIG_REPO" ]; then
    REPOCONF=$DIST/cvmfs/$CONFIG_REPO/etc/cvmfs/config.d/$REPO.conf
    if [ "$REPO" = oasis.opensciencegrid.org ]; then
        # OASIS_CERTIFICATES is one special variable we do not want relocated
        relocate $REPOCONF | sed 's,^\(OASIS_CERTIFICATES\)=.[^/]*,\1=/cvmfs,'
    else
        relocate $REPOCONF
    fi
fi
relocate $DIST/etc/cvmfs/config.d/$REPO.conf
relocate $DIST/etc/cvmfs/config.d/$REPO.local

# this is for finding an authz helper
echo CVMFS_AUTHZ_CVMFS_DIST=$DIST

) > $CONFFILE

OPTS=""
if grep -q ^CVMFS_DEBUGLOG=. $CONFFILE; then
    OPTS="$OPTS,debug"
fi

mkdir -p $DIST/var/run/cvmfs
mkdir -p $DIST/cvmfs/$REPO
if [ -f $DIST/usr/lib/libcvmfs_fuse.so ]; then
    LPATH=$DIST/usr/lib
    LDPATH=$LPATH
    if [ ! -f $LPATH/libfuse.so.2 ]; then
        # for el6
        LDPATH=$LPATH:$DIST/lib
    fi
else
    LPATH=$DIST/usr/lib64
    LDPATH=$LPATH
    if [ ! -f $LPATH/libfuse.so.2 ]; then
        # for el6
        LDPATH=$LPATH:$DIST/lib64
    fi
fi
LD_LIBRARY_PATH=$LDPATH CVMFS_LIBRARY_PATH=$LPATH $DIST/usr/bin/cvmfs2 -o config=$CONFFILE$OPTS $REPO $DIST/cvmfs/$REPO