Implementing FUSE

I want to implement a file system using FUSE. When the contents of the directory is requested, only the types of files in that directory will be reported as subdirectories. For example, if there are ugur.PDF, gu开发者_C百科ler.JPG and devatate.PNG files in the directory, the files themselves will not be reported, but types (PDF, JPG and PNG) will be reported instead. I tried to implement this file system. My problem is i can not imagine that how can i report without changing ls-l command? how does ls-l command work? (I have a readdir function and it loads file_type and file_name to buffer. I tried to change but i couldn't achive)

How does ls -l work? That seems to be the crux of the issue. It calls fstat(2). That system call fills the stat structure. When you implement a fuse provider, you are providing the data that ends up in the stat structure. If you want to change the directory structure, you return the necessary fabricated information for the various items.

I can think of two approaches to this: 1. Use a database like SQLite you can store the files, path and file types in the database. Then when the user gets into some directory, you can say do some query like select file_types where path="" and populate as directories using filler() 2. Recursively traverse original path you can create a list of all file types in the current directory, then use filler() to post them as directories. Then, when user enters any one directory, you can again do a check or something to see if cur_path is in last_path(orig directory), and you can select those file types and display them