Bound external result file reads

internal/adapters/seriatim/subprocess.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -14,6 +13,9 @@ import (
 	"gitea.maximumdirect.net/eric/narratio/internal/fileops"
 )
 
+// MaxOutputFileBytes bounds each Seriatim JSON or rendered-text result.
+const MaxOutputFileBytes int64 = 64 * 1024 * 1024
+
 // EnvConfig defines optional Seriatim environment tuning values.
 type EnvConfig struct {
 	OverlapWordRunGap           *float64
@@ -636,9 +638,9 @@ func writeRenderInvocationConfig(req RenderRequest, args []string, binary string
 }
 
 func validateJSONFile(path string) error {
-	data, err := os.ReadFile(path)
+	data, err := readSeriatimResult(path, "JSON output")
 	if err != nil {
-		return fmt.Errorf("read file: %w", err)
+		return err
 	}
 	var v any
 	if err := json.Unmarshal(data, &v); err != nil {
@@ -648,9 +650,9 @@ func validateJSONFile(path string) error {
 }
 
 func validateJSONFileWithSegments(path string) error {
-	data, err := os.ReadFile(path)
+	data, err := readSeriatimResult(path, "transcript JSON output")
 	if err != nil {
-		return fmt.Errorf("read file: %w", err)
+		return err
 	}
 
 	var payload map[string]any
@@ -669,9 +671,9 @@ func validateJSONFileWithSegments(path string) error {
 }
 
 func validateNonEmptyTextFile(path string) error {
-	data, err := os.ReadFile(path)
+	data, err := readSeriatimResult(path, "rendered text output")
 	if err != nil {
-		return fmt.Errorf("read file: %w", err)
+		return err
 	}
 	if len(data) == 0 {
 		return fmt.Errorf("file is empty")
@@ -684,3 +686,11 @@ func validateNonEmptyTextFile(path string) error {
 	}
 	return nil
 }
+
+func readSeriatimResult(path, category string) ([]byte, error) {
+	data, err := fileops.ReadRegularFile(path, MaxOutputFileBytes)
+	if err != nil {
+		return nil, fmt.Errorf("seriatim %s exceeds or cannot be read within %d-byte limit: %w", category, MaxOutputFileBytes, err)
+	}
+	return data, nil
+}