[acvptool] skip connection to the server if input json or regdump is on

If we are working with predownloaded test vectors we don't have
connection config file and don't want to connect to remote server.
So, skip this step.

Change-Id: I8a8c558ab11306850e39dfcda0e1c38c6d238a7a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/60865
Auto-Submit: Yurii Shutkin <shutkin@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

util/fipstools/acvp/acvptool/acvp.go

diff --git a/util/fipstools/acvp/acvptool/acvp.go b/util/fipstools/acvp/acvptool/acvp.go
index cbb07f6..60a952a 100644
--- a/util/fipstools/acvp/acvptool/acvp.go
+++ b/util/fipstools/acvp/acvptool/acvp.go
@@ -529,28 +529,6 @@
 func main() {
 	flag.Parse()
 
-	var config Config
-	if err := jsonFromFile(&config, *configFilename); err != nil {
-		log.Fatalf("Failed to load config file: %s", err)
-	}
-
-	var sessionTokensCacheDir string
-	if len(config.SessionTokensCache) > 0 {
-		sessionTokensCacheDir = config.SessionTokensCache
-		if strings.HasPrefix(sessionTokensCacheDir, "~/") {
-			home := os.Getenv("HOME")
-			if len(home) == 0 {
-				log.Fatal("~ used in config file but $HOME not set")
-			}
-			sessionTokensCacheDir = filepath.Join(home, sessionTokensCacheDir[2:])
-		}
-	}
-
-	if len(*uploadInputFile) > 0 {
-		uploadFromFile(*uploadInputFile, &config, sessionTokensCacheDir)
-		return
-	}
-
 	middle, err := subprocess.New(*wrapperPath)
 	if err != nil {
 		log.Fatalf("failed to initialise middle: %s", err)
@@ -667,6 +645,28 @@
 		}
 	}
 
+	var config Config
+	if err := jsonFromFile(&config, *configFilename); err != nil {
+		log.Fatalf("Failed to load config file: %s", err)
+	}
+
+	var sessionTokensCacheDir string
+	if len(config.SessionTokensCache) > 0 {
+		sessionTokensCacheDir = config.SessionTokensCache
+		if strings.HasPrefix(sessionTokensCacheDir, "~/") {
+			home := os.Getenv("HOME")
+			if len(home) == 0 {
+				log.Fatal("~ used in config file but $HOME not set")
+			}
+			sessionTokensCacheDir = filepath.Join(home, sessionTokensCacheDir[2:])
+		}
+	}
+
+	if len(*uploadInputFile) > 0 {
+		uploadFromFile(*uploadInputFile, &config, sessionTokensCacheDir)
+		return
+	}
+
 	server, err := connect(&config, sessionTokensCacheDir)
 	if err != nil {
 		log.Fatal(err)