Merge pull request #5601 from tautschnig/run-windows-error-reporting

run() Windows error reporting

Author: Daniel Kroening

src/util/run.cpp

@@ -219,6 +219,37 @@ std::wstring quote_windows_arg(const std::wstring &src)
 }
 #endif
 
+#ifdef _WIN32
+// https://stackoverflow.com/a/17387176
+// Returns the last Win32 error, in string format. Returns an empty string if
+// there is no error.
+std::string get_last_error_as_string()
+{
+  // Get the error message, if any.
+  DWORD error_message_id = GetLastError();
+  if(error_message_id == 0)
+    return {};
+
+  LPWSTR message_buffer = nullptr;
+  std::size_t size = FormatMessageW(
+    FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+      FORMAT_MESSAGE_IGNORE_INSERTS,
+    NULL,
+    error_message_id,
+    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+    (LPWSTR)&message_buffer,
+    0,
+    NULL);
+
+  std::wstring message(message_buffer, size);
+
+  // Free the buffer.
+  LocalFree(message_buffer);
+
+  return narrow(message);
+}
+#endif
+
 int run(
   const std::string &what,
   const std::vector<std::string> &argv,
@@ -272,12 +303,20 @@ int run(
 
   if(!bSuccess)
   {
+    // obtain the error message before doing further system calls
+    std::string windows_error = get_last_error_as_string();
+
     if(!std_input.empty())
       CloseHandle(siStartInfo.hStdInput);
     if(!std_output.empty())
       CloseHandle(siStartInfo.hStdOutput);
     if(!std_error.empty())
       CloseHandle(siStartInfo.hStdError);
+
+    // now re-open the file and write the above error message
+    std::ofstream stderr_stream(std_error);
+    stderr_stream << windows_error;
+
     return -1;
   }
 

unit/Makefile

@@ -118,6 +118,7 @@ SRC += analyses/ai/ai.cpp \
        util/prefix_filter.cpp \
        util/range.cpp \
        util/replace_symbol.cpp \
+       util/run.cpp \
        util/sharing_map.cpp \
        util/sharing_node.cpp \
        util/simplify_expr.cpp \

unit/util/run.cpp

@@ -0,0 +1,44 @@
+/*******************************************************************\
+
+Module: Unit test for run.h/run.cpp
+
+Author: Michael Tautschnig
+
+\*******************************************************************/
+
+#include <testing-utils/use_catch.h>
+
+#include <util/run.h>
+#include <util/tempfile.h>
+
+#include <fstream>
+
+SCENARIO("run() error reporting", "[core][util][run]")
+{
+  GIVEN("A command invoking a non-existent executable")
+  {
+    temporary_filet tmp_stderr("tmp.txt", "");
+
+    int result =
+      run("no-such-binary", {"no-such-binary"}, "", "", tmp_stderr());
+
+    THEN("run returns a non-zero exit code")
+    {
+      REQUIRE(result != 0);
+    }
+    THEN("run provides an error message")
+    {
+      std::ifstream read_output{tmp_stderr()};
+      std::string line;
+      REQUIRE(std::getline(read_output, line));
+#ifdef _WIN32
+      // strip terminating \r
+      REQUIRE(
+        Catch::trim(line) == "The system cannot find the file specified.");
+#else
+      REQUIRE(
+        line == "execvp no-such-binary failed: No such file or directory");
+#endif
+    }
+  }
+}