win32_extract_stream(): Pre-allocate stream length

[wimlib] / src / win32_apply.c

diff --git a/src/win32_apply.c b/src/win32_apply.c
index 9135a7db690839f714d27c7de8db635bde0af7e7..56f82b6bfab953922d7c8b8eb39ba8b7f66d9e28 100644 (file)
--- a/src/win32_apply.c
+++ b/src/win32_apply.c
@@ -402,23 +402,48 @@ win32_extract_stream(const wchar_t *path, const wchar_t *stream_name,
                       creationDisposition, FILE_FLAG_BACKUP_SEMANTICS |
                                            FILE_FLAG_OPEN_REPARSE_POINT,
                       NULL);
-       if (h == INVALID_HANDLE_VALUE)
-               goto error;
+       if (h == INVALID_HANDLE_VALUE) {
+               set_errno_from_GetLastError();
+               ret = WIMLIB_ERR_OPEN;
+               goto out;
+       }
 
-       ret = 0;
-       if (!lte)
+       if (!lte) {
+               ret = 0;
                goto out_close_handle;
+       }
+
+       if (!SetFilePointerEx(h,
+                             (LARGE_INTEGER) { .QuadPart = lte->size},
+                             NULL,
+                             FILE_BEGIN))
+               goto write_error;
+
+       if (!SetEndOfFile(h))
+               goto write_error;
+
+       if (!SetFilePointerEx(h,
+                             (LARGE_INTEGER) { .QuadPart = 0},
+                             NULL,
+                             FILE_BEGIN))
+               goto write_error;
+
        ret = extract_stream(lte, lte->size, win32_extract_wim_chunk, h);
-out_close_handle:
-       if (!CloseHandle(h))
-               goto error;
-       if (ret && !errno)
-               errno = -1;
-       return ret;
+       goto out_close_handle;
 
-error:
+write_error:
        set_errno_from_GetLastError();
-       return WIMLIB_ERR_WRITE;
+       ret = WIMLIB_ERR_WRITE;
+
+out_close_handle:
+       if (!CloseHandle(h)) {
+               if (!ret) {
+                       set_errno_from_GetLastError();
+                       ret = WIMLIB_ERR_WRITE;
+               }
+       }
+out:
+       return ret;
 }
 
 static int