genfs: add -s, strips n leading path components

diff --git a/app-tools/genfs.in b/app-tools/genfs.in
index f131cb9f3a2452ad04692291f6edc6bbaad375a1..4076a4e8583672c3d48511bcddd5857865d2452c 100644 (file)
--- a/app-tools/genfs.in
+++ b/app-tools/genfs.in
@@ -37,6 +37,20 @@ set -eu
 : ${RUMPRUN_GENFS_OBJCOPY:=!LIBEXEC_OBJCOPY!}
 : ${RUMPRUN_GENFS_INCDIR:=!DESTDIR!/rumprun-!MACHINE_GNU_ARCH!/include}
 
+usage ()
+{
+
+       echo "usage: $0 [-s count] outfile directory ..."
+       exit 1
+}
+
+die ()
+{
+
+       echo ">> ERROR: $*" 2>&1
+       exit 1
+}
+
 nuketmpdir ()
 {
 
@@ -50,12 +64,69 @@ trap nuketmpdir 0 INT TERM
 LINKPATH=${TMPDIR}/linkme
 LINKPATH_BIN="_binary_$(echo ${LINKPATH} | tr '/.-' '_')"
 
-[ $# -ge 2 ] || { echo "usage: $0 outfile directory ..."; exit 1; }
+STRIPCOUNT=0
+while getopts "s:" opt; do
+        case "${opt}" in
+       s)
+               STRIPCOUNT=${OPTARG}
+               [ -z "$(echo ${STRIPCOUNT} | tr -d '[0-9]')" ] \
+                   || die argument to -s must be a non-negative decimal
+               ;;
+       *)
+               usage
+               ;;
+       esac
+done
+shift $((${OPTIND}-1))
+
+[ $# -ge 2 ] || usage
 OUTFILE="$1"
 shift
 
+checkpaths ()
+{
+
+       stripcount=${1}
+       shift
+
+       for sd in "$@"; do
+               arg="${sd}"
+               IFS=/
+               set -- ${sd}
+               unset IFS
+               while [ "$1" = '.' ]; do shift ; done
+               [ $# -ge ${stripcount} ] || \
+                   die cannot remove ${STRIPCOUNT} components from \"${arg}\"
+       done
+}
+
+stripleading ()
+{
+
+       n=$1
+       path=$2
+
+       IFS=/
+       set -- ${path}
+       while [ "$1" = '.' ]; do shift ; done
+       while [ ${n} -gt 0 ]; do
+               shift
+               n=$((${n}-1))
+       done
+       unset IFS
+
+       rpath=
+       while [ $# -gt 0 ]; do
+               rpath="${rpath}$1/"
+               shift
+       done
+
+       echo ${rpath%/}
+}
+
 FILES=
 for sd in "$@"; do
+       checkpaths ${STRIPCOUNT} "$@"
        FILES="${FILES} $(find ${sd} -type f)"
 done
 
@@ -65,13 +136,13 @@ makedirlist ()
        for x in ${FILES}; do
                d=$(dirname $x)
                [ $d != . ] || continue
-               DIRS="${DIRS} /${d}"
+               DIRS="${DIRS} ${d}"
        done
        DIRS=$(echo ${DIRS} | xargs -n1 | sort | uniq)
 
        printf 'static const char *dirlist[] = {\n'
        for d in ${DIRS}; do
-               printf '\t"%s",\n' $d
+               printf '\t"/%s",\n' $(stripleading ${STRIPCOUNT} $d)
        done
        printf '};\n\n'
 }
@@ -118,7 +189,7 @@ makeelfdata ()
        fn=0
        for f in ${FILES}; do
                setfilevars %{f}
-               printf '\t{ "/%s",\n' ${f}
+               printf '\t{ "/%s",\n' $(stripleading ${STRIPCOUNT} "${f}")
                printf '\t    { (void *)&%s_start,\n' ${rf}
                printf '\t      (size_t)(uintptr_t)&%s_size} },\n' ${rf}
        done