VM: fix move_file called from save_image

save_image() shouldn't throw exceptions because if the 'then_die'
argument is t it would leave factor in an inconsistent state. So
therefore move_file() should be fixed and raw_fclose() called instead of
safe_fclose().

vm/factor.hpp

@@ -9,6 +9,7 @@ void open_console();
 void close_console();
 void lock_console();
 void unlock_console();
+bool move_file(const vm_char* path1, const vm_char* path2);
 
 void ignore_ctrl_c();
 void handle_ctrl_c();

vm/image.cpp

@@ -225,8 +225,10 @@ bool factor_vm::save_image(const vm_char* saving_filename,
     goto error;
   if (safe_fwrite((void*)code->allocator->start, h.code_size, 1, file) != 1)
     goto error;
-  safe_fclose(file);
-  move_file(saving_filename, filename);
+  if (raw_fclose(file) == -1)
+    goto error;
+  if (!move_file(saving_filename, filename))
+    goto error;
   return true;
 
  error:

vm/io.cpp

@@ -56,7 +56,7 @@ void factor_vm::io_error_if_not_EINTR() {
   general_error(ERROR_IO, tag_fixnum(errno), false_object);
 }
 
-FILE* factor_vm::safe_fopen(char* filename, char* mode) {
+FILE* factor_vm::safe_fopen(char* filename, const char* mode) {
   FILE* file;
   for (;;) {
     file = fopen(filename, mode);
@@ -159,11 +159,6 @@ void factor_vm::safe_fflush(FILE* stream) {
   }
 }
 
-void factor_vm::safe_fclose(FILE* stream) {
-  if (raw_fclose(stream) == -1)
-    io_error_if_not_EINTR();
-}
-
 void factor_vm::primitive_fopen() {
   data_root<byte_array> mode(ctx->pop(), this);
   data_root<byte_array> path(ctx->pop(), this);
@@ -245,7 +240,8 @@ void factor_vm::primitive_fflush() {
 
 void factor_vm::primitive_fclose() {
   FILE* file = pop_file_handle();
-  safe_fclose(file);
+  if (raw_fclose(file) == -1)
+    io_error_if_not_EINTR();
 }
 
 /* This function is used by FFI I/O. Accessing the errno global directly is

vm/os-unix.cpp

@@ -65,14 +65,13 @@ void factor_vm::primitive_existsp() {
   ctx->push(tag_boolean(stat(path, &sb) >= 0));
 }
 
-void factor_vm::move_file(const vm_char* path1, const vm_char* path2) {
+bool move_file(const vm_char* path1, const vm_char* path2) {
   int ret = 0;
   do {
     ret = rename((path1), (path2));
   } while (ret < 0 && errno == EINTR);
 
-  if (ret < 0)
-    general_error(ERROR_IO, tag_fixnum(errno), false_object);
+  return ret == 0;
 }
 
 void check_ENOMEM(const char* msg) {

vm/os-unix.hpp

@@ -51,7 +51,6 @@ inline static THREADHANDLE thread_id() { return pthread_self(); }
 uint64_t nano_count();
 void sleep_nanos(uint64_t nsec);
 
-void move_file(const vm_char* path1, const vm_char* path2);
 void check_ENOMEM(const char* msg);
 
 static inline void breakpoint() { __builtin_trap(); }

vm/os-windows.cpp

@@ -137,9 +137,8 @@ long getpagesize() {
   return g_pagesize;
 }
 
-void factor_vm::move_file(const vm_char* path1, const vm_char* path2) {
-  if (MoveFileEx((path1), (path2), MOVEFILE_REPLACE_EXISTING) == false)
-    general_error(ERROR_IO, tag_fixnum(GetLastError()), false_object);
+bool move_file(const vm_char* path1, const vm_char* path2) {
+  return MoveFileEx((path1), (path2), MOVEFILE_REPLACE_EXISTING);
 }
 
 void factor_vm::init_signals() {}

vm/os-windows.hpp

@@ -72,7 +72,6 @@ inline static void early_init() {}
 uint64_t nano_count();
 void sleep_nanos(uint64_t nsec);
 long getpagesize();
-void move_file(const vm_char* path1, const vm_char* path2);
 VM_C_API LONG exception_handler(PEXCEPTION_RECORD e, void* frame, PCONTEXT c,
                                 void* dispatch);
 THREADHANDLE start_thread(void* (*start_routine)(void*), void* args);

vm/vm.hpp

@@ -552,7 +552,6 @@ struct factor_vm {
   int safe_ftell(FILE* stream);
   void safe_fseek(FILE* stream, off_t offset, int whence);
   void safe_fflush(FILE* stream);
-  void safe_fclose(FILE* stream);
   void primitive_fopen();
   FILE* pop_file_handle();
   FILE* peek_file_handle();
@@ -731,7 +730,6 @@ struct factor_vm {
 
   // os-*
   void primitive_existsp();
-  void move_file(const vm_char* path1, const vm_char* path2);
   void init_ffi();
   void ffi_dlopen(dll* dll);
   cell ffi_dlsym(dll* dll, symbol_char* symbol);