From 1f9d8a43c216b2297db60184cd9ed63944942e07 Mon Sep 17 00:00:00 2001
From: Gilles Peskine <Gilles.Peskine@arm.com>
Date: Fri, 12 May 2023 13:18:08 +0200
Subject: [PATCH] Fuzz programs: print an error if loading the reproducer fails

The fuzz programs were returning a nonzero status if they failed to load the
reproducer, but that's discreet and not informative. Make them also print an
error message.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
---
 programs/fuzz/onefile.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/programs/fuzz/onefile.c b/programs/fuzz/onefile.c
index 4f80cdcec5..3b2709f805 100644
--- a/programs/fuzz/onefile.c
+++ b/programs/fuzz/onefile.c
@@ -14,34 +14,48 @@ int main(int argc, char **argv)
     FILE *fp;
     uint8_t *Data;
     size_t Size;
+    const char *argv0 = argv[0] == NULL ? "PROGRAM_NAME" : argv[0];
 
     if (argc != 2) {
+        fprintf(stderr, "Usage: %s REPRODUCER_FILE\n", argv0);
         return 1;
     }
     //opens the file, get its size, and reads it into a buffer
     fp = fopen(argv[1], "rb");
     if (fp == NULL) {
+        fprintf(stderr, "%s: Error in fopen\n", argv0);
+        perror(argv[1]);
         return 2;
     }
     if (fseek(fp, 0L, SEEK_END) != 0) {
+        fprintf(stderr, "%s: Error in fseek(SEEK_END)\n", argv0);
+        perror(argv[1]);
         fclose(fp);
         return 2;
     }
     Size = ftell(fp);
     if (Size == (size_t) -1) {
+        fprintf(stderr, "%s: Error in ftell\n", argv0);
+        perror(argv[1]);
         fclose(fp);
         return 2;
     }
     if (fseek(fp, 0L, SEEK_SET) != 0) {
+        fprintf(stderr, "%s: Error in fseek(0)\n", argv0);
+        perror(argv[1]);
         fclose(fp);
         return 2;
     }
     Data = malloc(Size);
     if (Data == NULL) {
+        fprintf(stderr, "%s: Could not allocate memory\n", argv0);
+        perror(argv[1]);
         fclose(fp);
         return 2;
     }
     if (fread(Data, Size, 1, fp) != 1) {
+        fprintf(stderr, "%s: Error in fread\n", argv0);
+        perror(argv[1]);
         free(Data);
         fclose(fp);
         return 2;