From 90f08dad7966e35558e5a8cd4948bcf5ed48c7de Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Wed, 9 Dec 2020 23:03:30 +0100
Subject: [PATCH] Handle output file errors correctly

---
 src/mkdwarfs.cpp | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/mkdwarfs.cpp b/src/mkdwarfs.cpp
index 3e4f70bc..aca05acb 100644
--- a/src/mkdwarfs.cpp
+++ b/src/mkdwarfs.cpp
@@ -21,6 +21,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cerrno>
 #include <cstdio>
 #include <cstring>
 #include <ctime>
@@ -607,7 +608,14 @@ int mkdwarfs(int argc, char** argv) {
   block_compressor bc(compression);
   block_compressor schema_bc(schema_compression);
   block_compressor metadata_bc(metadata_compression);
-  std::ofstream ofs(output);
+
+  std::ofstream ofs(output, std::ios::binary);
+
+  if (ofs.bad() || !ofs.is_open()) {
+    throw std::runtime_error(
+        fmt::format("cannot open '{}': {}", output, strerror(errno)));
+  }
+
   filesystem_writer fsw(ofs, lgr, wg_writer, prog, bc, schema_bc, metadata_bc,
                         mem_limit);
 
@@ -647,6 +655,13 @@ int mkdwarfs(int argc, char** argv) {
     }
   }
 
+  ofs.close();
+
+  if (ofs.bad()) {
+    throw std::runtime_error(
+        fmt::format("failed to close '{}': {}", output, strerror(errno)));
+  }
+
   return prog.errors > 0;
 }