miri: Improve handling of failed operations in isolation mode

Currently, we abort program execution when we try to access the external environment in isolation mode. However, libstd currently calls getcwd when printing out a panic backtrace. To ensure that panicking works in isolation mode, we’ve disabled the call to getcwd when libstd has cfg(miri) enabled.

Eventually, it would be good to remove this hack, and start returning proper error codes from disabled functions, rather than aborting the process.

See https://github.com/rust-lang/rust/pull/60026#discussion_r342257352 for more discussion

About this issue

Original URL
State: open
Created 5 years ago
Comments: 21 (18 by maintainers)

Commits related to this issue

Auto merge of #1838 - atsmtat:fs-isolation, r=RalfJung Fix use of deprecated `check_no_isolation` in posix fs shims Update posix fs shims to use new API `reject_in_isolation`, which allows rejection... — committed to rust-lang/miri by bors 3 years ago

Most upvoted comments

I guess most of the fs operations can return EPERM.

atsmtat on Jun 11, 2021

Hi @RalfJung , I opened a PR fixing get and set cwd ops. Let me know what you think. Also, this is my first PR in rustc related packages. If you find something missing from the usual workflow, please let me know 🙂

atsmtat on May 14, 2021

@henryboisdequin I never ended up getting to this, so you can try!

camelid on Mar 3, 2021

I’m going to try working on this.

camelid on Oct 24, 2020

Here’s another example where it would be good if isolated operations returned failure instead of aborting execution: https://github.com/seanmonstar/num_cpus/pull/96 makes num_cpus open a file (rejected with isolation) but falls back to another way of determining the CPU count (which works in isolation).

RalfJung on Sep 18, 2020