Place POSIX shadow files in /tmp on QNX, not the cwd - #112
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Channel::BufferSharedMemoryName only special-cased __APPLE__ for the /tmp shadow file path; other POSIX-mode platforms (notably QNX) fell through to the generic branch and returned a bare relative name. That created subspace_<session>_<channel>_<index> shadow files in the process's current working directory instead of /tmp, and made the server's cleanup miss them (leaking the underlying shm object) whenever the server and publishers ran from different directories. Key the /tmp path on SUBSPACE_SHMEM_MODE_POSIX so both macOS and QNX use it, and leave the Linux /dev/shm object-name path untouched.
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Summary
On QNX,
subspace_<sessionid>_<channel>_<index>files were being created in the current working directory of whatever process created a buffer, rather than in/tmp.These are the POSIX-mode shadow files: in
SUBSPACE_SHMEM_MODE_POSIX(macOS and QNX) the shared memory object is named/sized via a small on-disk file (its length records the buffer's true size, sincefstaton the shm object is page-aligned, and its inode names the shm object — seePosixSharedMemoryName).The bug was in
Channel::BufferSharedMemoryName: it only special-cased__APPLE__for the/tmp/prefix. QNX (also POSIX mode) fell through to the generic branch and returned a bare relative name, so:/tmp./tmp, missed these files and leaked the underlying shm object whenever the server and publishers ran from different working directories.Fix
Key the
/tmp/shadow-file path onSUBSPACE_SHMEM_MODE == SUBSPACE_SHMEM_MODE_POSIXso it applies to both macOS and QNX. The Linux/dev/shmpath is anshm_openobject name (not a filesystem path) and is left untouched.Test plan
bazelisk test //... --config=macos_arm64(POSIX mode) — all pass; macOS shadow-file path unchanged (still/tmp)./tmpand are cleaned up on channel/session teardown.