Module fs 

Filesystem-oriented low-level helpers.

This module contains lightweight Linux and Android file probes and helpers that are useful near the OS boundary, including path existence checks, page-cache read-ahead hints, and symlink-safe read/write primitives.

Structs

PathFingerprint

Constants

FADV_DONTNEED

FADV_NOREUSE

FADV_NORMAL

FADV_RANDOM

FADV_SEQUENTIAL

FADV_WILLNEED

Functions

ensure_state_dir

Create dir if needed, then verify it is a real directory with no symlink component and that it is owned by the current effective uid. Returning the anchored fd lets callers refuse to operate inside an attacker-pre-created or attacker-redirected state directory.

fadvise

Advise the kernel on the expected access pattern for a file range.

mmap_madvise

Map a file range, advise the kernel that it will be needed, then unmap it.

open_append_nofollow

Open an existing-or-create append stream that refuses to follow symlinks.

path_exists

Probe whether a filesystem path is accessible and exists.

path_fingerprint

Return a fingerprint of the file metadata at the specified path.

path_lstat_exists

Probe whether a path exists without following symbolic links.

read_nofollow

Read a file to a string, refusing to follow a symlink at the final or any parent component.

read_to_string

Read a file into a string.

readahead

Advise the kernel to begin reading file data into the page cache.

remove_nofollow

Remove a directory entry without following a final symlink, anchored to its (symlink-free) parent. The entry itself is removed even if it is a symlink; its target is never touched.

write_atomic

Atomically replace path with content.