Move format_win32_error into lib/log/

3 files changed, 77 insertions, 2 deletions

diff --git a/src/lib/log/include.am b/src/lib/log/include.am
index 235c95fdf1..22b141d316 100644
--- a/src/lib/log/include.am
+++ b/src/lib/log/include.am
@@ -9,7 +9,8 @@ src_lib_libtor_log_a_SOURCES =			\
 	src/lib/log/escape.c			\
 	src/lib/log/ratelim.c			\
 	src/lib/log/torlog.c			\
-	src/lib/log/util_bug.c
+	src/lib/log/util_bug.c			\
+	src/lib/log/win32err.c
 
 src_lib_libtor_log_testing_a_SOURCES = \
 	$(src_lib_libtor_log_a_SOURCES)
@@ -23,4 +24,5 @@ noinst_HEADERS +=					\
 	src/lib/log/escape.h				\
 	src/lib/log/ratelim.h				\
 	src/lib/log/torlog.h				\
-	src/lib/log/util_bug.h
+	src/lib/log/util_bug.h				\
+	src/lib/log/win32err.h
diff --git a/src/lib/log/win32err.c b/src/lib/log/win32err.c
new file mode 100644
index 0000000000..4586c23c84
--- /dev/null
+++ b/src/lib/log/win32err.c
@@ -0,0 +1,56 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifdef _WIN32
+#include "orconfig.h"
+#include "lib/log/win32err.h"
+#include "lib/malloc/util_malloc.h"
+
+#include <tchar.h>
+#include <windows.h>
+
+/** Return a newly allocated string describing the windows system error code
+ * <b>err</b>.  Note that error codes are different from errno.  Error codes
+ * come from GetLastError() when a winapi call fails.  errno is set only when
+ * ANSI functions fail.  Whee. */
+char *
+format_win32_error(DWORD err)
+{
+  TCHAR *str = NULL;
+  char *result;
+  DWORD n;
+
+  /* Somebody once decided that this interface was better than strerror(). */
+  n = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                 FORMAT_MESSAGE_FROM_SYSTEM |
+                 FORMAT_MESSAGE_IGNORE_INSERTS,
+                 NULL, err,
+                 MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
+                 (LPVOID)&str,
+                 0, NULL);
+
+  if (str && n) {
+#ifdef UNICODE
+    size_t len;
+    if (n > 128*1024)
+      len = (128 * 1024) * 2 + 1; /* This shouldn't be possible, but let's
+                                   * make sure. */
+    else
+      len = n * 2 + 1;
+    result = tor_malloc(len);
+    wcstombs(result,str,len);
+    result[len-1] = '\0';
+#else /* !(defined(UNICODE)) */
+    result = tor_strdup(str);
+#endif /* defined(UNICODE) */
+  } else {
+    result = tor_strdup("<unformattable error>");
+  }
+  if (str) {
+    LocalFree(str); /* LocalFree != free() */
+  }
+  return result;
+}
+#endif /* defined(_WIN32) */
diff --git a/src/lib/log/win32err.h b/src/lib/log/win32err.h
new file mode 100644
index 0000000000..61d3af57dd
--- /dev/null
+++ b/src/lib/log/win32err.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_WIN32ERR_H
+#define TOR_WIN32ERR_H
+
+#include "orconfig.h"
+
+/* Platform-specific helpers. */
+#ifdef _WIN32
+#include <windef.h>
+char *format_win32_error(DWORD err);
+#endif
+
+#endif