Daniel Rainer c0f91a50fa fix: avoid race conditions of mkstemp ...

The `mkstemp` function opens files without setting `O_CLOEXEC`. We could
manually set this using `fnctl` once the file is opened, but that has
the issue of introducing race conditions. If fish `exec`s in another
thread before the `fnctl` call completes, the file would be left open.

One way of mitigating this is `mkostemp`, but that function is not
available on all systems fish supports, so we can't rely on it.

Instead, build our own tempfile creation logic which uses the `rand`
crate for getting entropy and relies on Rust's stdlib for the rest.
The stdlib functions we use set `O_CLOEXEC` by default.

For directory creation we keep using `mkdtemp`, since there we don't
open anything. We could replace this by extending our custom logic a
bit, which would allow us to drop the `nix` dependency for our
`tempfile` crate, but since the code is simpler as it is now and we need
nix in fish's main crate, there is no need to modify the directory
creation code.

Part of #12030

2025-12-08 16:51:20 +00:00

..

src

fix: avoid race conditions of mkstemp

2025-12-08 16:51:20 +00:00

Cargo.toml

fix: avoid race conditions of mkstemp

2025-12-08 16:51:20 +00:00