Set mtime of all initramfs files and directories to 01-01-1970

Mtime files are not important for executing the image. But at the same
time, the constancy of mtime makes it possible to acquire the
reproducibility of the image. The same image will be generated on the
same hardware and with the same configuration.

Signed-off-by: Alexey Gladkov <[email protected]>

features/ucode/bin/add-ucode

@@ -51,13 +51,10 @@ prep_early_firmware()
 		return 0
 	fi
 
-	cd "$workdir"
-	mkdir -p kernel/x86/microcode
-	cp ${VERBOSE:+-v} -- "$fw_file" kernel/x86/microcode/"$cpu_vendor".bin
-	find ./kernel | cpio -o -H newc >"$workdir"/ucode.cpio && \
-	    rm -rf -- kernel
-
-	return $?
+	mkdir "$workdir"/ucode ||
+		return
+	mkdir -p -- "$workdir"/ucode/kernel/x86/microcode
+	cp ${VERBOSE:+-v} -- "$fw_file" "$workdir"/ucode/kernel/x86/microcode/"$cpu_vendor".bin
 }
 
 prep_amd_ucode()
@@ -89,8 +86,10 @@ prep_intel_ucode()
 					--quiet \
 					$iucode_scan_system \
 					--write-earlyfw="$workdir"/ucode.cpio \
-					"$fw_path"/intel-ucode && \
-				return 0 ||:
+					"$fw_path"/intel-ucode
+			mkdir "$workdir"/ucode &&
+				cpio -D "$workdir"/ucode --quiet -id < "$workdir"/ucode.cpio
+			return
 		fi
 	done
 
@@ -105,5 +104,22 @@ case "$cpu_vendor" in
 	*) exit 0
 		;;
 esac
+rc=$?
+
+if [ -d "$workdir/ucode" ]; then
+	cd "$workdir/ucode"
+
+	find . -execdir touch -c -m --date="1970-01-01 00:00:00 +0000" '{}' '+'
+
+	# shellcheck disable=SC2185
+	find -O2 . -mindepth 1 \
+		   \( -type f -a -printf 'file %p %p %#m 0 0\n'  \) \
+		-o \( -type l -a -printf 'slink %p %l %#m 0 0\n' \) \
+		-o \( -type d -a -printf 'dir %p %#m 0 0\n'      \) |
+		sort |
+		gen_init_cpio -t 0 - > "$workdir"/ucode.cpio
+
+	rm -rf -- "$workdir/ucode"
+fi
 
-exit $?
+exit $rc

tools/pack-image

@@ -26,4 +26,7 @@ printf >> "$workdir"/initcpio 'nod ./dev/%s\n' \
 	"console 0600 0 0 c 5 1" \
 	"ptmx    0666 0 0 c 5 2"
 
-gen_init_cpio "$workdir"/initcpio > "$outfile"
+find . -execdir touch -c -m --date="1970-01-01 00:00:00 +0000" '{}' '+'
+
+sort "$workdir"/initcpio |
+	gen_init_cpio -t 0 - > "$outfile"