Step1: build with busybox.

Signed-off-by: Chen Wang <wangchen20@iscas.ac.cn>

support/scripts/check-host-rpath

@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+
+# This script scans $(HOST_DIR)/{bin,sbin} for all ELF files, and checks
+# they have an RPATH to $(HOST_DIR)/lib if they need libraries from
+# there.
+
+# Override the user's locale so we are sure we can parse the output of
+# readelf(1) and file(1)
+export LC_ALL=C
+
+main() {
+    local pkg="${1}"
+    local hostdir="${2}"
+    local perpackagedir="${3}"
+    local file ret
+
+    # Remove duplicate and trailing '/' for proper match
+    hostdir="$( sed -r -e 's:/+:/:g; s:/$::;' <<<"${hostdir}" )"
+
+    ret=0
+    while read file; do
+        is_elf "${file}" || continue
+        elf_needs_rpath "${file}" "${hostdir}" || continue
+        check_elf_has_rpath "${file}" "${hostdir}" "${perpackagedir}" && continue
+        if [ ${ret} -eq 0 ]; then
+            ret=1
+            printf "***\n"
+            printf "*** ERROR: package %s installs executables without proper RPATH:\n" "${pkg}"
+        fi
+        printf "***   %s\n" "${file}"
+    done < <( find "${hostdir}"/{bin,sbin} -type f 2>/dev/null )
+
+    return ${ret}
+}
+
+is_elf() {
+    local f="${1}"
+
+    readelf -l "${f}" 2>/dev/null \
+    |grep -E 'Requesting program interpreter:' >/dev/null 2>&1
+}
+
+# This function tells whether a given ELF executable (first argument)
+# needs a RPATH pointing to the host library directory or not. It
+# needs such an RPATH if at least of the libraries used by the ELF
+# executable is available in the host library directory. This function
+# returns 0 when a RPATH is needed, 1 otherwise.
+#
+# With per-package directory support, ${hostdir} will point to the
+# current package per-package host directory, and this is where this
+# function will check if the libraries needed by the executable are
+# located (or not). In practice, the ELF executable RPATH may point to
+# another package per-package host directory, but that is fine because
+# if such an executable is within the current package per-package host
+# directory, its libraries will also have been copied into the current
+# package per-package host directory.
+elf_needs_rpath() {
+    local file="${1}"
+    local hostdir="${2}"
+    local lib
+
+    while read lib; do
+        [ -e "${hostdir}/lib/${lib}" ] && return 0
+    done < <( readelf -d "${file}" 2>/dev/null                             \
+              |sed -r -e '/^.* \(NEEDED\) .*Shared library: \[(.+)\]$/!d;' \
+                     -e 's//\1/;'                                          \
+            )
+
+    return 1
+}
+
+# This function checks whether at least one of the RPATH of the given
+# ELF executable (first argument) properly points to the host library
+# directory (second argument), either through an absolute RPATH or a
+# relative RPATH. In the context of per-package directory support,
+# ${hostdir} (second argument) points to the current package host
+# directory. However, it is perfectly valid for an ELF binary to have
+# a RPATH pointing to another package per-package host directory,
+# which is why such RPATH is also accepted (the per-package directory
+# gets passed as third argument). Having a RPATH pointing to the host
+# directory will make sure the ELF executable will find at runtime the
+# shared libraries it depends on. This function returns 0 when a
+# proper RPATH was found, or 1 otherwise.
+check_elf_has_rpath() {
+    local file="${1}"
+    local hostdir="${2}"
+    local perpackagedir="${3}"
+    local rpath dir
+
+    while read rpath; do
+        for dir in ${rpath//:/ }; do
+            # Remove duplicate and trailing '/' for proper match
+            dir="$( sed -r -e 's:/+:/:g; s:/$::;' <<<"${dir}" )"
+            [ "${dir}" = "${hostdir}/lib" ] && return 0
+            [ "${dir}" = "\$ORIGIN/../lib" ] && return 0
+            # This check is done even for builds where
+            # BR2_PER_PACKAGE_DIRECTORIES is disabled. In this case,
+            # PER_PACKAGE_DIR and therefore ${perpackagedir} points to
+            # a non-existent directory, and this check will always be
+            # false.
+            [[ ${dir} =~ "${perpackagedir}/"[^/]+/host/lib ]] && return 0
+        done
+    done < <( readelf -d "${file}" 2>/dev/null                                  \
+              |sed -r -e '/.* \(R(UN)?PATH\) +Library r(un)?path: \[(.+)\]$/!d' \
+                      -e 's//\3/;'                                              \
+            )
+
+    return 1
+}
+
+main "${@}"