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write_atomic_beneath

mermaid_cli::runtime

Function write_atomic_beneath 

Source 
pub fn write_atomic_beneath(
    root: &Path,
    rel: &Path,
    bytes: &[u8],
) -> Result<(), Error>
Expand description

Atomically write bytes to root-relative rel without ever traversing out of root. The temp file is created and renameat-swapped beneath the same confined directory fd as the destination (Linux openat2(RESOLVE_BENEATH)), so a parent dir swapped for an escaping symlink after a path check can’t redirect the write (#77), AND a crash/kill/disk-full mid-write leaves the previous file intact instead of a truncated one — open_beneath + WriteTruncate gives the first guarantee but not the second. Falls back to contain_within_canonical + by-path crate::write_atomic on non-Linux / pre-openat2 kernels (the same best-effort posture as the other helpers).