[FS] opening file failure now reported properly

Author: di

kernel/filesystem/fat32.cpp

@@ -256,7 +256,7 @@ FS_RESULT FAT32FS::open_file(const char* path, file* descriptor){
     uint32_t count = count_FAT(mbs->first_cluster_of_root_directory);
     sizedptr buf_ptr = walk_directory(count, mbs->first_cluster_of_root_directory, path, read_entry_handler);
     void *buf = (void*)buf_ptr.ptr;
-    if (!buf) return FS_RESULT_NOTFOUND;
+    if (!buf || !buf_ptr.size) return FS_RESULT_NOTFOUND;
     descriptor->id = fid;
     descriptor->size = buf_ptr.size;
     mfile = (module_file*)kalloc(fs_page, sizeof(module_file), ALIGN_64B, MEM_PRIV_KERNEL);

kernel/filesystem/filesystem.cpp

@@ -154,7 +154,8 @@ FS_RESULT open_file_global(const char* path, file* descriptor, system_module **m
 //TODO: exclusive write. Keep track of permissions for opening, if writing is already taken, don't grant. Could allow non-exclusive write as well with manual cursor seek
 FS_RESULT open_file(const char* path, file* descriptor){
     system_module *mod = 0;
-    open_file_global(path, descriptor, &mod);
+    FS_RESULT result = open_file_global(path, descriptor, &mod);
+    if (result != FS_RESULT_SUCCESS) return result;
     open_file_descriptors *of = (open_file_descriptors*)kalloc(page, sizeof(open_file_descriptors), ALIGN_16B, MEM_PRIV_KERNEL);
     of->mfile_id = descriptor->id;
     of->file_id = reserve_fd_id();

shared/files/fs.h

@@ -18,7 +18,7 @@ typedef enum SEEK_TYPE {
 } SEEK_TYPE;
 
 typedef enum FS_RESULT {
+    FS_RESULT_DRIVER_ERROR,
     FS_RESULT_SUCCESS,
     FS_RESULT_NOTFOUND,
-    FS_RESULT_DRIVER_ERROR,
 } FS_RESULT;