[Buildroot] [PATCH] support/scripts/fix-rpath: parallelize patching files

[Victor Dumas]

Using "xargs" instead of "while read" loop allows for the patching of files to be parallelized, significantly reducing the amount of time it takes to fix all the paths.
On a larger RFS(~300MB) this script was taking 5 minutes, it now only takes about 30s on a 12 core machine

Signed-off-by: Victor Dumas <dumasv.dev at gmail.com>
---
 support/scripts/fix-rpath | 62 +++++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 26 deletions(-)

diff --git a/support/scripts/fix-rpath b/support/scripts/fix-rpath
index 3e67e770e5..c9d40e1cce 100755
--- a/support/scripts/fix-rpath
+++ b/support/scripts/fix-rpath
@@ -58,6 +58,40 @@ HOST_EXCLUDEPATHS="/share/terminfo"
 STAGING_EXCLUDEPATHS="/usr/include /usr/share/terminfo"
 TARGET_EXCLUDEPATHS="/lib/firmware"
 
+patch_file() {
+    PATCHELF="${1}"
+    rootdir="${2}"
+    sanitize_extra_args="${3}"
+    file="${4}"
+
+    echo "patch file $file"
+
+    # check if it's an ELF file
+    rpath=$(${PATCHELF} --print-rpath "${file}" 2>&1)
+    if test $? -ne 0 ; then
+        return 0
+    fi
+
+    # make files writable if necessary
+    changed=$(chmod -c u+w "${file}")
+
+    # With per-package directory support, most RPATH of host
+    # binaries will point to per-package directories. This won't
+    # work with the --make-rpath-relative ${rootdir} invocation as
+    # the per-package host directory is not within ${rootdir}. So,
+    # we rewrite all RPATHs pointing to per-package directories so
+    # that they point to the global host directry.
+    changed_rpath=$(echo ${rpath} | sed "s@${PER_PACKAGE_DIR}/[^/]\+/host@${HOST_DIR}@")
+    if test "${rpath}" != "${changed_rpath}" ; then
+        ${PATCHELF} --set-rpath ${changed_rpath} "${file}"
+    fi
+
+    # call patchelf to sanitize the rpath
+    ${PATCHELF} --make-rpath-relative "${rootdir}" ${sanitize_extra_args[@]} "${file}"
+    # restore the original permission
+    test "${changed}" != "" && chmod u-w "${file}"
+}
+
 main() {
     local rootdir
     local tree="${1}"
@@ -125,32 +159,8 @@ main() {
 
     find_args+=( "-type" "f" "-print" )
 
-    while read file ; do
-        # check if it's an ELF file
-        rpath=$(${PATCHELF} --print-rpath "${file}" 2>&1)
-        if test $? -ne 0 ; then
-            continue
-        fi
-
-        # make files writable if necessary
-        changed=$(chmod -c u+w "${file}")
-
-        # With per-package directory support, most RPATH of host
-        # binaries will point to per-package directories. This won't
-        # work with the --make-rpath-relative ${rootdir} invocation as
-        # the per-package host directory is not within ${rootdir}. So,
-        # we rewrite all RPATHs pointing to per-package directories so
-        # that they point to the global host directry.
-        changed_rpath=$(echo ${rpath} | sed "s@${PER_PACKAGE_DIR}/[^/]\+/host@${HOST_DIR}@")
-        if test "${rpath}" != "${changed_rpath}" ; then
-            ${PATCHELF} --set-rpath ${changed_rpath} "${file}"
-        fi
-
-        # call patchelf to sanitize the rpath
-        ${PATCHELF} --make-rpath-relative "${rootdir}" ${sanitize_extra_args[@]} "${file}"
-        # restore the original permission
-        test "${changed}" != "" && chmod u-w "${file}"
-    done < <(find "${rootdir}" ${find_args[@]})
+    export -f patch_file
+    find "${rootdir}" ${find_args[@]} -print0 | xargs -0 -r -d '\n' -P $(nproc) -I {} bash -c "patch_file '${PATCHELF}' '${rootdir}' '${sanitize_extra_args}' $@" _ {}
 
     # Restore patched patchelf utility
     test "${tree}" = "host" && mv "${PATCHELF}.__to_be_patched" "${PATCHELF}"
-- 
2.30.2