write (nr 1)

Linux Signature

ssize_t write(int fd, const void *buf, size_t count);

Description

Writes up to count bytes from buf to file descriptor fd.

Current Implementation

Looks up fd in the current process’s per-process file descriptor table and calls FileHandle::write() on the handle.

• fd 1 (stdout) and fd 2 (stderr) — ConsoleHandle: Interprets buf as UTF-8 and prints to the VGA text buffer via print!(). If not valid UTF-8, falls back to printing printable ASCII (0x20..0x7F) plus \n, \r, \t. Returns count on success.
• VFS file fds — VfsHandle: Returns -EBADF (-9) — files are read-only.
• Invalid fds: Returns -EBADF (-9).

Validates that buf falls within user address space (< 0x0000_8000_0000_0000). Returns -EFAULT (-14) on invalid pointers.

Source: osl/src/syscalls/io.rs — sys_write

Future Work

• Support writable VFS files.
• Handle partial writes.