[PATCH v2 4/4] mbuto: Automatically add links related to linker

[Lukasz Gut <lgut@lgut.eu>]

Fix dynamic linking on Arch Linux by adding (some of) missing links.

The ldd reports linker in many ways:
ldd /usr/lib/libreadline.so.8
    /usr/lib64/ld-linux-x86-64.so.2 (0x000071244211c000)
ldd /bin/sh
    /lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2
    (0x000077457d5ec000)
ldd /usr/lib/libc.so.6
    /usr/lib/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2
    (0x000075d218b8b000)

This patch looks at the left side and determines if there is a link
there, then adds it.

Signed-off-by: Lukasz Gut <lgut@lgut.eu>
---
 mbuto | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/mbuto b/mbuto
index 4f860cd..7d67160 100755
--- a/mbuto
+++ b/mbuto
@@ -668,6 +668,27 @@ libs_dlopen_copy() {
 	done
 }
 
+# libs_add_links() - Rebuild alternate links to ld as they appear on the host
+# $1:	String returned by ldd in form 's => d' describing location of ld
+libs_add_links() {
+	__ld_path="${1##*=> }"
+	__ld_link="${1%%=>*}"
+	[ -z "${__ld_link}" ] && return
+	[ "${__ld_path}" = "${__ld_link}" ] && return
+	while [ "${__ld_link}" != "/" ]; do
+		if [ -L "${__ld_link}" ]; then
+			__target="$("${READLINK}" -f "${__ld_link}")"
+			__link="$("${REALPATH}" -s "${__ld_link}" --relative-to "/")"
+			__link="${wd}"/"${__link}"
+			[ -L "${__link}" ] && break
+			__destdir="$("${DIRNAME}" "${__link}")"
+			"${MKDIR}" -p "${__destdir}"
+			"${LN}" -s "${__target}" "${__link}"
+		fi
+		__ld_link="$("${DIRNAME}" "${__ld_link}")"
+	done
+}
+
 # __libs_copy() - Recursively copy shared dependencies for programs, libraries
 # $1:	Host path to program or library
 __libs_copy() {
@@ -716,8 +737,13 @@ __libs_copy() {
 
 	if [ -n "${__ld_path}" ]; then
 		libs_copy_ld_so "${__ld_path}"
-		libs_path_add "${__ld_path##${wd}}"
+		libs_path_add "${__ld_path##"${wd}"}"
 	fi
+
+	# On Arch Linux, to execute /bin/sh, the system expects the linker
+	# to be under /lib64. Linker is located in /usr/lib, and there is
+	# a link /lib64 => /usr/lib.
+	libs_add_links "${__ld_so}"
 }
 
 # libs_copy() - Call __libs_copy with tabs and newlines as IFS
-- 
@@ -668,6 +668,27 @@ libs_dlopen_copy() {
 	done
 }
 
+# libs_add_links() - Rebuild alternate links to ld as they appear on the host
+# $1:	String returned by ldd in form 's => d' describing location of ld
+libs_add_links() {
+	__ld_path="${1##*=> }"
+	__ld_link="${1%%=>*}"
+	[ -z "${__ld_link}" ] && return
+	[ "${__ld_path}" = "${__ld_link}" ] && return
+	while [ "${__ld_link}" != "/" ]; do
+		if [ -L "${__ld_link}" ]; then
+			__target="$("${READLINK}" -f "${__ld_link}")"
+			__link="$("${REALPATH}" -s "${__ld_link}" --relative-to "/")"
+			__link="${wd}"/"${__link}"
+			[ -L "${__link}" ] && break
+			__destdir="$("${DIRNAME}" "${__link}")"
+			"${MKDIR}" -p "${__destdir}"
+			"${LN}" -s "${__target}" "${__link}"
+		fi
+		__ld_link="$("${DIRNAME}" "${__ld_link}")"
+	done
+}
+
 # __libs_copy() - Recursively copy shared dependencies for programs, libraries
 # $1:	Host path to program or library
 __libs_copy() {
@@ -716,8 +737,13 @@ __libs_copy() {
 
 	if [ -n "${__ld_path}" ]; then
 		libs_copy_ld_so "${__ld_path}"
-		libs_path_add "${__ld_path##${wd}}"
+		libs_path_add "${__ld_path##"${wd}"}"
 	fi
+
+	# On Arch Linux, to execute /bin/sh, the system expects the linker
+	# to be under /lib64. Linker is located in /usr/lib, and there is
+	# a link /lib64 => /usr/lib.
+	libs_add_links "${__ld_so}"
 }
 
 # libs_copy() - Call __libs_copy with tabs and newlines as IFS
-- 
2.46.1