73 lines
1.5 KiB
Markdown
73 lines
1.5 KiB
Markdown
# AbleOS VFS
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## Public API
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```
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// reads the whole file
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pub fn read(file: FileHandle) -> Vec<u8>
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// overwrites the contents of the file
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pub fn write(file: FileHandle, data: Vec<u8>)
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// opens a file for reading and writing
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pub fn open(path: Path)
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// closes the file
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pub fn close(file: FileHandle)
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// deletes a file
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pub fn delete(path: Path)
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```
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Opening a file opens it using the corresponding filesystem. Multiple processes can open the same file in any mode, and the file only leaves the FS cache when no process has it open anymore.
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## Minimal FS API
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```
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trait FileIO {
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// reads the whole file
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pub fn read(path: Path) -> Vec<u8>
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// overwrites the file contents
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pub fn write(path: Path, data: Vec<u8>)
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// opens a file for reading and writing
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pub fn open(path: Path)
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// closes a file, removing it from the cache
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pub fn close(path: Path)
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// deletes a file
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pub fn delete(path: Path)
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}
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```
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All filesystems must expose at least these functions in order to work with the VFS.
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## Structure
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### Mount Point Lookup Entry
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```
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path_len: u64
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path: [u8; <path_len>]
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entries: u64
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addr: u64
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```
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There is one of these for each mount point, stored sequentially. The list ends when it finds a path_len of 0
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### Sub Part
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```
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name_len: u64
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name: [u8; <name_len>]
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dir: u8
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size: u64
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addr: u64
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```
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There can be many of these in a mount point, and they can be nested within eachother. dir is 1 if the part is a directory, or 0 if it's a file. size specifies the number of sub parts within a directory, or the number of bytes within a file |