std: treat ENFILE as transient in the pidfd support probe#158486
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std: treat ENFILE as transient in the pidfd support probe#158486valentynkit wants to merge 2 commits into
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The probe handles EMFILE (per-process fd limit) as a transient error and re-probes later, but lets ENFILE (system-wide fd limit) fall through to the catch-all arm meant for an old kernel without pidfd support, which permanently caches the pidfd path as unsupported. ENFILE is the same transient condition, so handle both.
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…, r=joboet
std: treat ENFILE as transient in the pidfd support probe
The pidfd support probe special-cases `EMFILE` from `pidfd_open`: it returns the
error without caching anything, so the next spawn re-probes. `ENFILE` falls
through instead, into the fallback arm, so the probe caches pidfd as unsupported
for the rest of the process, even after descriptors free up.
Both errnos come from the same `pidfd_open` call and mean the same thing: the
process is out of file descriptors, just per-process (`EMFILE`) vs system-wide
(`ENFILE`). I don't see a reason to treat them differently here, so this handles
`ENFILE` the same way:
```rust
Err(e) if matches!(e.raw_os_error(), Some(libc::EMFILE | libc::ENFILE)) => {
```
I kept the raw `raw_os_error()` check rather than `ErrorKind::TooManyOpenFiles`
(rust-lang#158326, which maps both) to match the rest of this probe, but can switch if
you'd prefer.
I didn't add a test, since triggering it needs real fd exhaustion during the
probe, which isn't practical to reproduce. The `EMFILE` arm isn't tested either.
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…uwer Rollup of 4 pull requests Successful merges: - #158486 (std: treat ENFILE as transient in the pidfd support probe) - #158454 (regression test for `Trait<A><B>` in "consider further restricting this bound" suggestion) - #158518 (Fix mixed use of "a" / "an" article in E0277) - #158519 (add crashtests [2/N])
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The pidfd support probe special-cases
EMFILEfrompidfd_open: it returns theerror without caching anything, so the next spawn re-probes.
ENFILEfallsthrough instead, into the fallback arm, so the probe caches pidfd as unsupported
for the rest of the process, even after descriptors free up.
Both errnos come from the same
pidfd_opencall and mean the same thing: theprocess is out of file descriptors, just per-process (
EMFILE) vs system-wide(
ENFILE). I don't see a reason to treat them differently here, so this handlesENFILEthe same way:I kept the raw
raw_os_error()check rather thanErrorKind::TooManyOpenFiles(#158326, which maps both) to match the rest of this probe, but can switch if
you'd prefer.
I didn't add a test, since triggering it needs real fd exhaustion during the
probe, which isn't practical to reproduce. The
EMFILEarm isn't tested either.r? libs