Fix canonical path on Windows when accessing mounted DwarFS image

include/dwarfs/util.h

@@ -23,6 +23,7 @@
 
 #include <chrono>
 #include <cstddef>
+#include <filesystem>
 #include <string>
 
 #include "dwarfs/types.h"
@@ -49,4 +50,6 @@ size_t utf8_display_width(std::string const& str);
 
 void shorten_path_string(std::string& path, char separator, size_t max_len);
 
+std::filesystem::path canonical_path(std::filesystem::path p);
+
 } // namespace dwarfs

src/dwarfs/util.cpp

@@ -173,4 +173,18 @@ void shorten_path_string(std::string& path, char separator, size_t max_len) {
   }
 }
 
+std::filesystem::path canonical_path(std::filesystem::path p) {
+  try {
+    p = std::filesystem::canonical(p);
+  } catch (std::filesystem::filesystem_error const&) {
+    p = std::filesystem::absolute(p);
+  }
+
+#ifdef _WIN32
+  p = std::filesystem::path(L"\\\\?\\" + p.wstring());
+#endif
+
+  return p;
+}
+
 } // namespace dwarfs

src/dwarfs_main.cpp

@@ -994,7 +994,7 @@ int option_hdl(void* data, char const* arg, int key,
       return 1;
     }
 
-    opts->fsimage = std::filesystem::canonical(
+    opts->fsimage = canonical_path(
         std::filesystem::path(reinterpret_cast<char8_t const*>(arg)));
 
     return 0;

src/mkdwarfs_main.cpp

@@ -676,11 +676,7 @@ int mkdwarfs_main(int argc, sys_char** argv) {
     }
   }
 
-  path = std::filesystem::canonical(path);
-
-#ifdef _WIN32
-  path = std::filesystem::path(L"\\\\?\\" + path.wstring());
-#endif
+  path = canonical_path(path);
 
   bool recompress = vm.count("recompress");
   rewrite_options rw_opts;