lsinitcpio: extract the image to a tempdir

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.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

1 files changed, 45 insertions, 18 deletions

diff --git a/lsinitcpio b/lsinitcpio
index 5abe37f..1c52d68 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 +141,52 @@ 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*)
+    if [[ -f ${modules[0]} ]]; then
+        modules=("${modules[@]##*/}")
+        modules=("${modules[@]%.ko*}")
+    else
+        unset modules
+    fi
+
+    foundhooks=("$workdir"/hooks/*)
+    [[ -f ${foundhooks[0]} ]] && foundhooks=("${foundhooks[@]##*/}") || unset 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