Add TCP short-write regression test - #1095
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Adds an LD_PRELOAD shim (short_write_shim.c) that intercepts send() and injects a short write on P_DATA_V1/V2 packets, and a test script (t_short_write.sh) that confirms stream corruption results. Currently FAILs — the bug is present. Linux-only; exits 77 (SKIP) elsewhere. Wires the shim and script into tests/Makefile.am under a TARGET_LINUX guard; adds that conditional to configure.ac.
A short write on a TCP socket left the stream corrupt. Track partial writes and retry until the packet drains.
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This PR adds a self-contained regression test that demonstrates the bug reported in issue #1094: link_socket_write_tcp_posix() calls send() once with no retry, and a short write permanently corrupts the TCP framing.
The test currently FAILs (bug present). It is intended to be paired with a follow-up fix, after which it should PASS.
What's included
tests/short_write_shim.c: An LD_PRELOAD shim that intercepts send() and injects a short write on P_DATA_V1/P_DATA_V2 packets (opcodes 6 and 9), while letting TLS handshake traffic pass through unmodified. This ensures the session is fully established before the data channel is corrupted.tests/t_short_write.sh: A test script that starts a loopback TCP server, runs a client with the shim preloaded, and checks whether the truncation warning appears in the log. Exit 1 (FAIL) = bug present; exit 0 (PASS) = bug fixed; exit 77 (SKIP) = prerequisites missing (e.g. macOS, missing binary).tests/Makefile.am: shim and script wired into the test suite under a TARGET_LINUX guard.configure.ac: adds the TARGET_LINUX conditional (mainly because I have no other platforms available)How to run
No root or tun device required the test uses
--dev null --ping 1with the existing sample keys.