tool_operate: avoid fclose(NULL) on bad header dump file

Fixes #10570
Reported-by: Jérémy Rabasco
Closes #10571

diff --git a/src/tool_operate.c b/src/tool_operate.c
index 195159229af660228c56335f1b8c1576dd085198..cec24057a6cbcac0fcd5f284f55840311e825d18 100644 (file)
--- a/src/tool_operate.c
+++ b/src/tool_operate.c
@@ -984,12 +984,13 @@ static CURLcode single_transfer(struct GlobalConfig *global,
              */
             if(!per->prev || per->prev->config != config) {
               newfile = fopen(config->headerfile, "wb+");
-              fclose(newfile);
+              if(newfile)
+                fclose(newfile);
             }
             newfile = fopen(config->headerfile, "ab+");
 
             if(!newfile) {
-              warnf(global, "Failed to open %s\n", config->headerfile);
+              errorf(global, "Failed to open %s\n", config->headerfile);
               result = CURLE_WRITE_ERROR;
               break;
             }