Report open error for missing trace directory

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Don't rely on /tmp or $TMPDIR in tests.
 - Fix misleading message in version check.
+- Fix error message when opening missing trace directories
 
 ## [1.2.1] - 2022-07-25
 

src/emu/trace.c

@@ -4,10 +4,12 @@
 #define _XOPEN_SOURCE 500
 
 #include "trace.h"
+#include <dirent.h>
 #include <ftw.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
 #include "ovni.h"
 #include "path.h"
 #include "stream.h"
@@ -125,6 +127,18 @@ trace_load(struct trace *trace, const char *tracedir)
 		return -1;
 	}
 
+	/* Try to open the directory to catch permission errors */
+	DIR *dir = opendir(tracedir);
+	if (dir == NULL) {
+		err("cannot open \"%s\":", tracedir);
+		return -1;
+	}
+
+	if (closedir(dir) != 0) {
+		err("closedir failed:");
+		return -1;
+	}
+
 	/* Search recursively all streams in the trace directory */
 	if (nftw(tracedir, cb_nftw, 50, 0) != 0) {
 		err("nftw failed");