universalisos/docs/T11_VFS_SOCKETS.md

T11: Virtual Filesystem (VFS) & Sockets

Track: T11
Status: IN PROGRESS
Date: 2026-07-12
Source: UniversalisOS 12-Month Roadmap, Month 11

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Overview

T11 focuses on enabling a fully functional virtual filesystem and networking endpoints for UniversalisOS. This includes fleshing out the VFS implementation, ensuring proper memory management, and implementing socket operations.

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Objectives

1. Flesh out VFS implementation — Complete VFS with proper memory management
2. Implement VFS socket operations — socket, bind, listen, accept
3. Ensure munmap correctly frees memory — Proper resource cleanup
4. Add socket options — setsockopt, getsockopt
5. Add socket I/O — send, recv, sendto, recvfrom

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Tasks

T11-1: VFS Implementation Completion

Status: PENDING

Complete the VFS implementation with proper memory management:

/* VFS operations */
int vfs_open(const char* path, int flags, int mode, uint32_t part_id);
int vfs_close(int fd, uint32_t part_id);
int vfs_read(int fd, void* buf, size_t count, uint32_t part_id);
int vfs_write(int fd, const void* buf, size_t count, uint32_t part_id);
int vfs_lseek(int fd, int offset, int whence, uint32_t part_id);
int vfs_fstat(int fd, void* statbuf, uint32_t part_id);
int vfs_ioctl(int fd, int request, void* arg, uint32_t part_id);

Key Features:

• File descriptor table per partition
• Path resolution
• File operations (open, close, read, write, lseek)
• File status (fstat)
• I/O control (ioctl)

TODO:

• Implement fd table per partition
• Implement path resolution
• Implement file operations
• Implement fstat
• Implement ioctl

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T11-2: VFS Socket Operations

Status: PENDING

Implement VFS socket operations:

/* Socket operations */
int vfs_socket(int domain, int type, int protocol, uint32_t part_id);
int vfs_bind(int sockfd, const void* addr, size_t addrlen, uint32_t part_id);
int vfs_listen(int sockfd, int backlog, uint32_t part_id);
int vfs_accept(int sockfd, void* addr, void* addrlen, uint32_t part_id);
int vfs_connect(int sockfd, const void* addr, size_t addrlen, uint32_t part_id);

Key Features:

• Socket creation (AF_INET, AF_UNIX, AF_INET6)
• Socket binding
• Connection listening
• Connection acceptance
• Connection establishment

TODO:

• Implement socket creation
• Implement socket binding
• Implement listen
• Implement accept
• Implement connect

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T11-3: Socket I/O Operations

Status: PENDING

Implement socket I/O operations:

/* Socket I/O */
ssize_t vfs_send(int sockfd, const void* buf, size_t len, int flags, uint32_t part_id);
ssize_t vfs_recv(int sockfd, void* buf, size_t len, int flags, uint32_t part_id);
ssize_t vfs_sendto(int sockfd, const void* buf, size_t len, int flags, const void* dest_addr, size_t addrlen, uint32_t part_id);
ssize_t vfs_recvfrom(int sockfd, void* buf, size_t len, int flags, void* src_addr, size_t* addrlen, uint32_t part_id);

Key Features:

• Send data
• Receive data
• Send to specific address
• Receive from specific address

TODO:

• Implement send
• Implement recv
• Implement sendto
• Implement recvfrom

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T11-4: Socket Options

Status: PENDING

Implement socket options:

/* Socket options */
int vfs_setsockopt(int sockfd, int level, int optname, const void* optval, size_t optlen, uint32_t part_id);
int vfs_getsockopt(int sockfd, int level, int optname, void* optval, size_t* optlen, uint32_t part_id);

Key Features:

• Set socket options (SO_REUSEADDR, SO_KEEPALIVE, etc.)
• Get socket options

TODO:

• Implement setsockopt
• Implement getsockopt

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T11-5: Memory Management for VFS

Status: PENDING

Ensure proper memory management for VFS:

/* Memory management */
int vfs_munmap(void* addr, size_t length, uint32_t part_id);
void* vfs_mmap(void* addr, size_t length, int prot, int flags, int fd, int offset, uint32_t part_id);

Key Features:

• Proper munmap (free memory resources)
• Memory-mapped files
• Resource cleanup

TODO:

• Implement proper munmap
• Implement mmap for files
• Implement resource cleanup

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Implementation Files

File	Purpose
kernel/src/core/vfs.h	VFS header
kernel/src/core/vfs.cpp	VFS implementation
kernel/src/core/abi/uos_posix_abi.cpp	POSIX ABI dispatch
kernel/src/core/abi/uos_posix_abi.h	POSIX ABI header

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Verification

• VFS operations work correctly
• Socket operations work correctly
• Socket I/O works correctly
• Socket options work correctly
• Memory management works correctly

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TODO Summary

T11-1: VFS Implementation

• Implement fd table per partition
• Implement path resolution
• Implement file operations
• Implement fstat
• Implement ioctl

T11-2: Socket Operations

• Implement socket creation
• Implement socket binding
• Implement listen
• Implement accept
• Implement connect

T11-3: Socket I/O

• Implement send
• Implement recv
• Implement sendto
• Implement recvfrom

T11-4: Socket Options

• Implement setsockopt
• Implement getsockopt

T11-5: Memory Management

• Implement proper munmap
• Implement mmap for files
• Implement resource cleanup

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References

• universalisos/docs/UniversalisOS_Stubs_Resolution_Roadmap_12Months.md — 12-month roadmap
• universalisos/kernel/src/core/vfs.cpp — VFS implementation
• universalisos/kernel/src/core/abi/uos_posix_abi.cpp — POSIX ABI dispatch