[PATCH 2/2] livepatch-build-tools: do not use readlink -m option

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Busybox readlink implementation only supports the -f option to follow symlinks,
so adjust the logic in order to keep the same behaviour without using the -m
option.

Singed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 livepatch-build | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/livepatch-build b/livepatch-build
index 26c88a2ed2c3..2f35e98d30a3 100755
--- a/livepatch-build
+++ b/livepatch-build
@@ -336,8 +336,8 @@ while [[ $# -gt 0 ]]; do
             ;;
         --xen-syms)
             shift
-            XENSYMS="$(readlink -m -- "$1")"
-            [ -f "$XENSYMS" ] || die "xen-syms file does not exist"
+            [ -f "$1" ] || die "xen-syms file does not exist"
+            XENSYMS="$(readlink -f -- "$1")"
             shift
             ;;
         --depends)
@@ -366,22 +366,20 @@ while [[ $# -gt 0 ]]; do
 done
 
 [ -z "$srcarg" ] && die "Xen directory not given"
+[ -d "$srcarg" ] || die "Xen directory does not exist"
 [ -z "$patcharg" ] && die "Patchfile not given"
+[ -f "$patcharg" ] || die "Patchfile does not exist"
 [ -z "$configarg" ] && die ".config not given"
+[ -f "$configarg" ] || die ".config does not exist"
 [ -z "$outputarg" ] && die "Output directory not given"
 [ -z "$DEPENDS" ] && die "Build-id dependency not given"
 [ -z "$XEN_DEPENDS" ] && die "Xen Build-id dependency not given"
 
-SRCDIR="$(readlink -m -- "$srcarg")"
+SRCDIR="$(readlink -f -- "$srcarg")"
 # We need an absolute path because we move around, but we need to
 # retain the name of the symlink (= realpath -s)
 PATCHFILE="$(readlink -f "$(dirname "$patcharg")")/$(basename "$patcharg")"
-CONFIGFILE="$(readlink -m -- "$configarg")"
-OUTPUT="$(readlink -m -- "$outputarg")"
-
-[ -d "${SRCDIR}" ] || die "Xen directory does not exist"
-[ -f "${PATCHFILE}" ] || die "Patchfile does not exist"
-[ -f "${CONFIGFILE}" ] || die ".config does not exist"
+CONFIGFILE="$(readlink -f -- "$configarg")"
 
 PATCHNAME=$(make_patch_name "${PATCHFILE}")
 
@@ -390,17 +388,20 @@ echo
 echo "Xen directory: ${SRCDIR}"
 echo "Patch file: ${PATCHFILE}"
 echo ".config file: ${CONFIGFILE}"
-echo "Output directory: ${OUTPUT}"
+echo "Output directory: $outputarg"
 echo "================================================"
 echo
 
 if [ "${SKIP}" != "build" ]; then
-    [ -e "${OUTPUT}" ] && die "Output directory exists"
+    # Make sure output directory doesn't exist, and create it.
+    [ -e "$outputarg" ] && die "Output directory exists"
+    mkdir -p "$outputarg" || die
+    OUTPUT="$(readlink -f -- "$outputarg")"
+
     grep -q 'CONFIG_LIVEPATCH=y' "${CONFIGFILE}" || die "CONFIG_LIVEPATCH must 
be enabled"
     cd "$SRCDIR" || die
     patch -s -N -p1 -f --fuzz=0 --dry-run < "$PATCHFILE" || die "Source patch 
file failed to apply"
 
-    mkdir -p "${OUTPUT}" || die
     cp -f "${CONFIGFILE}" "${OUTPUT}/.config"
     cp -f "${OUTPUT}/.config" "xen/.config"
 
@@ -453,7 +454,9 @@ if [ "${SKIP}" != "build" ]; then
 fi
 
 if [ "${SKIP}" != "diff" ]; then
-    [ -d "${OUTPUT}" ] || die "Output directory does not exist"
+    cd "${SCRIPTDIR}" || die
+    [ -d "$outputarg" ] || die "Output directory does not exist"
+    OUTPUT="$(readlink -f -- "$outputarg")"
 
     cd "${OUTPUT}" || die
     create_patch
-- 
2.43.0