Add a SessionsSnapshot view over the new C ABI entry point and
serve it from the admin server as GET /rc-sessions. The admin server
gains a WithAdminRoute option so an embedding binary can register
extra admin routes that run with the same signature verification and
admin checks as the built-in endpoints; vgwrdma registers the
snapshot there when the RC feature is enabled. The route replies
with the usual XML error surface so unsigned or non-admin requests
get a 403 rather than a generic 500. Stub builds return a not
supported error, keeping the build matrix unchanged.
The Prepare and ReadyTransfer wrappers embed string views built from
Go heap strings inside request structs passed to C by pointer. The
cgo pointer check rejects such requests when the string data is an
unpinned Go heap pointer, so any live PREPARE or READY call with
header-derived strings panicked at the call boundary and the route
returned a 500. Constant strings passed the check because their data
lives in read-only static storage, which is why standalone callers
kept working while the gateway did not.
Pin the string bytes with runtime.Pinner for the duration of the cgo
call and drop the now redundant KeepAlive calls in those two
wrappers. The other string-taking wrappers pass rc_str_in by value
and are unaffected.
Also add a deviceless cgo boundary regression test that calls the
real Prepare wrapper with heap-backed interior-pointer strings and an
invalid opcode, so C returns from argument validation before the
server handle is touched.
Jihyeon Gim