[arch-projects] [mkinitcpio][PATCH 18/19] lsinitcpio: extract the image to a tempdir

[Dave Reisner]

On Sun, May 13, 2012 at 01:39:35PM -0500, Dan McGee wrote:
> On Sun, May 13, 2012 at 12:57 PM, Dave Reisner <dreisner at archlinux.org> wrote:
> > We read the image a number of times. Extract the image to a temp
> > directory so we can just extract it once and use the filesystem to our
> > advantage. This requires a temp dir which we can nuke on an EXIT trap,
> > but the whole operation is sped is a bit, especially for larger images.
> >
> > The real goal of this is to make examination of the hooks easier. Since
> > we now have multiple hook sets to contend with, dynamically tally up the
> > available functions in the hook files so we can iterate over specific
> > functions of interest in the output.
> >
> > Signed-off-by: Dave Reisner <dreisner at archlinux.org>
> > ---
> 
> You missed one:
>         TIMEFORMAT=%R decomptime=$({ time decomp "$image" >/dev/null; } 2>&1 )
> 
> This is guarded by a 'if compressed' block now, but it is probably
> useful even if you are using an uncompressed tar image- there is still
> work being done in reading and breaking the individual files out of
> the tarfile.
> 

Sure, we can placate the few weirdos who don't compress their images at
all. This patch was more interested in getting rid of the archive reads
for: scanning binaries/modules/hooks + extracting the config +
extracting the version file.

Added locally as a separate patch.

> >  lsinitcpio |   59 +++++++++++++++++++++++++++++++++++++++++------------------
> >  1 file changed, 41 insertions(+), 18 deletions(-)
> >
> > diff --git a/lsinitcpio b/lsinitcpio
> > index 5abe37f..f33d9d3 100755
> > --- a/lsinitcpio
> > +++ b/lsinitcpio
> > @@ -59,7 +59,6 @@ size_to_human() {
> >     }'
> >  }
> >
> > -
> >  OPT_SHORT='ahnvx'
> >  OPT_LONG=('analyze' 'help' 'nocolor' 'verbose' 'extract')
> >
> > @@ -127,6 +126,9 @@ if (( analyze )); then
> >     declare -a binaries explicitmod modules foundhooks hooks
> >     declare kernver ratio columns=$(tput cols)
> >
> > +    workdir=$(mktemp -d --tmpdir="$TMPDIR" lsinitcpio.XXXXXX)
> > +    trap 'rm -rf "$workdir"' EXIT
> > +
> >     # fallback in case tput failed us
> >     columns=${columns:-80}
> >
> > @@ -139,27 +141,48 @@ if (( analyze )); then
> >         ratio=.$(( zsize * 1000 / fullsize % 1000 ))
> >     fi
> >
> > -    # read contents of image
> > -    while read -r line; do
> > -        if [[ $line = *.ko?(.?z) ]]; then
> > -            line=${line##*/}
> > -            modules+=("${line%.ko?(.?z)}")
> > -        elif [[ -z $kernver && $line =~ /lib/modules/([^/]+)/ ]]; then
> > -            kernver=${BASH_REMATCH[1]}
> > -        elif [[ $line = ./hooks/* ]]; then
> > -            foundhooks+=("${line##*/}")
> > -        elif [[ $line = *@(/?(s)bin/)* ]]; then
> > -            binaries+=("${line##*/}")
> > -        fi
> > -    done < <(decomp "$image" | bsdtar tf -)
> > -
> > -    read -r version < <(decomp "$image" | bsdtar xOf - VERSION 2>/dev/null)
> > +    # decompress the image since we need to read from it multiple times
> > +    decomp "$image" | bsdtar -C "$workdir" -xf -
> > +
> > +    # collect stats
> > +    kernver=("$workdir"/usr/lib/modules/*/)
> > +    kernver=${kernver%/}
> > +    kernver=${kernver##*/}
> > +
> > +    modules=("$workdir/usr/lib/modules/$kernver"/kernel/*.ko*)
> > +    modules=("${modules[@]##*/}")
> > +    modules=("${modules[@]%.ko*}")
> > +
> > +    foundhooks=("$workdir"/hooks/*)
> > +    foundhooks=("${foundhooks[@]##*/}")
> > +
> > +    binaries=("$workdir"/usr/bin/*)
> > +    binaries=("${binaries[@]##*/}")
> > +
> > +    read -r version < "$workdir/VERSION"
> >
> >     # source and read config
> > -    . <(decomp "$image" | bsdtar xOf - config)
> > +    . "$workdir/config"
> > +
> >     explicitmod=($MODULES)
> > +
> >     for hook in $HOOKS; do
> > -        in_array "$hook" "${foundhooks[@]}" && hooks+=("$hook")
> > +        [[ -e $workdir/hooks/$hook ]] || continue
> > +
> > +        mapfile -t funcs < \
> > +            <(awk '
> > +                /^[[:space:]]*[[:alnum:]_]+/ && /\([[:space:]]*\)/ {
> > +                    match($1, /[[:alnum:]_]+/)
> > +                    print substr($1, RSTART, RLENGTH)
> > +                }' "$workdir/hooks/$hook")
> > +
> > +        for fn in "${funcs[@]}"; do
> > +            case $fn in
> > +                run_hook)
> > +                    hooks+=("$hook")
> > +                    ;;
> > +            esac
> > +        done
> >     done
> >
> >     # print results
> > --
> > 1.7.10.2
> >