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The first time this project has had a second process. fork + execve of a real server image, the control socket surviving the exec, bytes crossing a process boundary, and the child exiting on EOF with nothing left behind. mobilegl_server_main EXISTS NOW. a6 found ARCHITECTURE.md:488-496 had described it for three phases while the symbol was nowhere in the tree, and the only MobileGLServer target was the P0 spike stub, which links no MobileGL library at all. The spike keeps its evidence and its name becomes MobileGLServerSpike; the real image links the library, so an undefined symbol is a build error rather than a dlsym failure in a child whose stderr is /dev/null. WHAT sm OWNS AND WHAT IT LEAVES: the process, the inherited descriptors, the transport and the exit discipline. Not the session, not the applier, not the four segments - wiring those from ServerMain before lk has a seam to wire them THROUGH is how call sites get written twice. The loop is a read/answer/exit-on- EOF stand-in whose SHAPE is the part that matters: one reader, EOF ends the process, and no timeout is ever allowed to stand in for the death fact (§5.4). ANTI-RECURSION IS TWO CATCHES, and neither is ARCHITECTURE.md:488's. That rule says the child hard-sets Transport to Monolith; a6 measured that 226 live lines test `Transport != Monolith` to select the SERVER arm, 148 in MG_Backend, so obeying it flips the whole backend to frontend glue in the one process with no frontend. Instead: (a) MOBILEGL_IPC_DIAL=no, structural and separate from role, and (b) MOBILEGL_TRANSPORT and every MOBILEGL_IPC_* scrubbed from the child's envp. The child refuses with 64 for (a) and 65 for (b) so the two safeties are distinguishable - two that cannot be told apart are one. TWO BUGS WORTH RECORDING, both found by the test rather than by review: dup2(n, n) IS A NO-OP THAT DOES NOT CLEAR CLOSE-ON-EXEC. FdPassing sets SOCK_CLOEXEC on the aux pair, so the child depends on dup2 to clear it - but in a gtest process a fresh socketpair lands on exactly fds 3..8, so a source fd often IS its own target. The no-op left CLOEXEC set and the following close() then shut the descriptor we had just "installed". The child came up with no socket and the parent saw TRANSPORT_CLOSED on its first send. Now spelled out rather than written cleverly. THE CHILD'S DIAGNOSTICS WERE INVISIBLE. WireLogError reaches the file sink only - Defines.h builds the logger with the console sink off - so a child that refused to start said so into a file the parent does not know the path of. ARCHITECTURE.md §15.2 warns about exactly this on Android. Both refusal paths now also write stderr directly, and both carry a distinct exit code the parent can name without reading anything. TESTS: six cases, 6/6. Each exists because something would otherwise pass silently - the reply carries the child's own getpid() so a test that talked to itself cannot pass (ID-124's lesson at the smallest scale); the process tree is COUNTED before, during and after, not promised; the child is proven not to exit while merely idle before it is proven to exit on EOF; an unresolvable image is a named refusal that spawns nothing (S1); a surviving client knob is caught by name (S3); and a descriptor crosses execve by SCM_RIGHTS, which is the mechanism the four segments will ride on and is now exercised before it is needed. Also records the asio decision in the contract: declined for P6 because spawn needs five platform mechanisms and asio covers one - its own socketpair returns operation_not_supported on Windows, it has no descriptor passing, segment delivery is POSIX-only by design, and there is no fork. Revisit at P6.5, where asio::generic::stream_protocol carries a raw family/type/protocol triple and therefore gives AF_VSOCK from one implementation. Gates: unit suite 2346, up 6, same two pre-existing environmental failures. G1 pull 0 added / 0 removed, .text size 10822147 unchanged, and zero spawn, server or SocketTransport symbols in the pull build.
20 lines
864 B
C++
20 lines
864 B
C++
// MobileGL - MobileGL/MG_Remote/Server/ServerEntry.cpp
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// Copyright (c) 2025-2026 MobileGL-Dev
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// Licensed under the GNU Lesser General Public License v3.0:
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// https://www.gnu.org/licenses/gpl-3.0.txt
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// https://www.gnu.org/licenses/lgpl-3.0.txt
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// SPDX-License-Identifier: LGPL-3.0-only
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// End of Source File Header
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// The server image's main(). Package `sm`.
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//
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// Deliberately the smallest thing that can be one: everything it could do
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// belongs to mobilegl_server_main, which lives IN THE LIBRARY so that one
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// shared library serves both roles (ARCHITECTURE.md:496). Keeping this file
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// empty of logic is what stops the server growing a second, divergent copy of
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// bring-up that the client half never executes.
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extern "C" int mobilegl_server_main(int argc, char** argv);
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int main(int argc, char** argv) { return mobilegl_server_main(argc, argv); }
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