Previously, only shared memory segments were cleaned up.
This could lead to leaked message queues and semaphore sets when builds use System V IPC, exhausting kernel IPC limits over time.
This commit extends the cleanup to all three System V IPC types:
1. Shared memory segments
2. Message queues
3. Semaphores
Additionally, we stop removing IPC objects during iteration, as it could corrupt the kernel's iterator state and cause some objects to be skipped. The new implementation uses a two-pass approach where we list first and then remove them in a separate pass.
The IPC IDs are now extracted during iteration using actual system calls (shmget, msgget, semget) rather than being looked up later, ensuring the objects exist when we capture their IDs.
In Linux, IPC objects are automatically cleaned up when the IPC namespace is destroyed.
On Darwin, since there are no IPC namespaces, the IPC objects may sometimes persist after the build user's processes are killed.
This patch modifies the cleanup logic to use sysctl calls to identify and remove left over shm segments associated with the build user.
Fixes: #12548
For repos with a lot of non-linearity in the commit graph (like
Nixpkgs), this speeds up getting the revcount a lot, e.g. `nix flake
metadata /path/to/nixpkgs?rev=9dc7035bbee85ffc740d893e02cb64460f11989f` went
from 9.1s to 3.7s.
Warning:
```
[39/483] Generating src/kaitai-struct-checks/kaitai-generated-sources with a custom command
../src/kaitai-struct-checks/nar.ksy: /types/padded_str/seq/1/encoding:
warning: use canonical encoding name `ASCII` instead of `ascii` (see https://doc.kaitai.io/ksy_style_guide.html#encoding-name)
```
Progress on #13405, which asks for an explicit characterisation of the
equivalence relation like the one given here.
Also progress on #11895, because we're using the term "build trace
entry" instead of "realisation".
Mention #9259, a future work item.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
It is better to avoid null termination for performance and memory
safety, wherever possible.
These are good cleanups extracted from the Pascal String work that we
can land by themselves first, shrinking the diff in that PR.
Co-Authored-By: Aspen Smith <root@gws.fyi>
Co-Authored-By: Sergei Zimmerman <sergei@zimmerman.foo>
Add three configuration settings to `S3BinaryCacheStoreConfig` to control
multipart upload behavior:
- `bool multipart-upload` (default `false`): Enable/disable multipart uploads
- `uint64_t multipart-chunk-size` (default 5 MiB): Size of each upload part
- `uint64_t multipart-threshold` (default 100 MiB): Minimum file size for multipart
The feature is disabled by default.
Refactor `ExprConcatStrings::eval` by inlining two only-called-once
closures into the call-site, so that the code is easier to reason about
locally (especially since the variables that were closed over were
mutated all over the place within this function).
Also use curly braces with each branch for consistency in the the
resulting code.
This is a pure refactor, but also arguably causes us to depend less on
the optimizer; now, we don't have to make sure that this closure is
inlined.
3a3c062982 introduced a buffer overflow for the
case when there are more than 65535 formal arguments. It is a perfectly reasonable
limitation, but we *must* not crash, corrupt memory or otherwise crash the process.
Add a test for the graceful behavior and switch to using an explicit uninitialized_copy_n
to further guard against buffer overflows.
