Close the windows file handle after CreateFileMapping; it isn't needed

I did the changes file; the rest came pseudonymously

changes/close_file_handle

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Don't hold a windows file handle open for every file mapping;
+      the file mapping handle is sufficient. Fix for bug 5951; bugfix on
+      0.1.2.1-alpha.

src/common/compat.c

@@ -175,24 +175,24 @@ tor_mmap_file(const char *filename)
   TCHAR tfilename[MAX_PATH]= {0};
   tor_mmap_t *res = tor_malloc_zero(sizeof(tor_mmap_t));
   int empty = 0;
-  res->file_handle = INVALID_HANDLE_VALUE;
+  HANDLE file_handle = INVALID_HANDLE_VALUE;
   res->mmap_handle = NULL;
 #ifdef UNICODE
   mbstowcs(tfilename,filename,MAX_PATH);
 #else
   strlcpy(tfilename,filename,MAX_PATH);
 #endif
-  res->file_handle = CreateFile(tfilename,
+  file_handle = CreateFile(tfilename,
                                 GENERIC_READ, FILE_SHARE_READ,
                                 NULL,
                                 OPEN_EXISTING,
                                 FILE_ATTRIBUTE_NORMAL,
                                 0);
 
-  if (res->file_handle == INVALID_HANDLE_VALUE)
+  if (file_handle == INVALID_HANDLE_VALUE)
     goto win_err;
 
-  res->size = GetFileSize(res->file_handle, NULL);
+  res->size = GetFileSize(file_handle, NULL);
 
   if (res->size == 0) {
     log_info(LD_FS,"File \"%s\" is empty. Ignoring.",filename);
@@ -200,7 +200,7 @@ tor_mmap_file(const char *filename)
     goto err;
   }
 
-  res->mmap_handle = CreateFileMapping(res->file_handle,
+  res->mmap_handle = CreateFileMapping(file_handle,
                                        NULL,
                                        PAGE_READONLY,
 #if SIZEOF_SIZE_T > 4
@@ -218,6 +218,7 @@ tor_mmap_file(const char *filename)
   if (!res->data)
     goto win_err;
 
+  CloseHandle(file_handle);
   return res;
  win_err: {
     DWORD e = GetLastError();
@@ -234,6 +235,8 @@ tor_mmap_file(const char *filename)
  err:
   if (empty)
     errno = ERANGE;
+  if (file_handle != INVALID_HANDLE_VALUE)
+    CloseHandle(file_handle);
   tor_munmap_file(res);
   return NULL;
 }
@@ -247,8 +250,6 @@ tor_munmap_file(tor_mmap_t *handle)
 
   if (handle->mmap_handle != NULL)
     CloseHandle(handle->mmap_handle);
-  if (handle->file_handle != INVALID_HANDLE_VALUE)
-    CloseHandle(handle->file_handle);
   tor_free(handle);
 }
 #else

src/common/compat.h

@@ -249,7 +249,6 @@ typedef struct tor_mmap_t {
   size_t mapping_size; /**< Size of the actual mapping. (This is this file
                         * size, rounded up to the nearest page.) */
 #elif defined MS_WINDOWS
-  HANDLE file_handle;
   HANDLE mmap_handle;
 #endif