libmakepkg: strip - parallelize stripping of files

Perform file stripping in parallel where possible. Hardlinks remain
processed one at a time due to reproducibility issues.

Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/libmakepkg/tidy/strip.sh.in

@@ -190,9 +190,27 @@ tidy_strip() {
 			mkdir -p "$dbgdir" "$dbgsrc"
 		fi
 
-		while IFS= read -rd '' binary ; do
-			process_file_stripping "$binary"
-		done < <(find . -type f -perm -u+w -links 1 -print0 2>/dev/null)
+		_parallel_stripper() {
+			# Inherit traps in subshell to perform cleanup after an interrupt
+			set -E
+			(
+				local jobs binary
+
+				while IFS= read -rd '' binary ; do
+					# Be sure to keep the number of concurrently running processes less
+					# than limit value to prevent an accidental fork bomb.
+					jobs=($(jobs -p))
+					(( ${#jobs[@]} >= $NPROC )) && wait -n "${jobs[@]}"
+
+					process_file_stripping "$binary" &
+				done < <(find . -type f -perm -u+w -links 1 -print0 2>/dev/null)
+
+				# Wait for all jobs to complete
+				wait
+			)
+			set +E
+		}
+		_parallel_stripper
 
 		# hardlinks only need processed once, but need additional links in debug packages
 		declare -A hardlinks

scripts/makepkg.sh.in

@@ -106,6 +106,9 @@ trap_exit() {
 	fi
 	[[ -n $srclinks ]] && rm -rf "$srclinks"
 
+	# Kill all child processes so that they are not left orphaned upon exit.
+	[[ -n "$(jobs -p)" ]] && kill "$(jobs -p)" 2>/dev/null
+
 	# unset the trap for this signal, and then call the default handler
 	trap -- "$signal"
 	kill "-$signal" "$$"