[php-src] Issue #24229: fcgi_close() passes shutdown() a literal 1, which is SHUT_RD in WASI

Issue: https://github.com/php/php-src/issues/24229 Author: mpyw The quoted description below was written with an LLM (Claude). I reviewed it, and ran the checks it describes myself. > ### Description > > fcgi_close() in main/fastcgi.c > half-closes the connection with a literal 1: > > ```c > if (!force) { > char buf[8]; > > shutdown(req->fd, 1); > /* read any remaining data, it may be omitted */ > while (recv(req->fd, buf, sizeof(buf), 0) > 0) {} > } > close(req->fd); > ``` > > 1 means SHUT_WR only where > SHUT_WR is 1. POSIX names the constants, but does not fix their > values. Every platform PHP supports today uses 1, and Windows' > SD_SEND is 1 too, so nothing breaks there. > > WASI numbers them from 1 instead. wasi-libc's > <__header_sys_socket.h> has: > > ```c > #define SHUT_RD 1 > #define SHUT_WR 2 > #define SHUT_RDWR (SHUT_RD | SHUT_WR) > ``` > > So a php-cgi built for wasm32-wasip1 shuts the reading side > instead. The drain loop then ends at once, and close() runs while > the web server's last FCGI_STDIN record may still be unread. > Linux answers that with a reset, which discards the response that php-cgi already sent but the web > server had not read yet. The web server sees a broken pipe, or a connection reset, instead of > FCGI_END_REQUEST. > > I hit this running php-cgi in FastCGI mode (-b) on wazero, a > WebAssembly runtime, behind a Go FastCGI client. About 1 in 60 requests failed on Linux. macOS did > not show it. With SHUT_WR, 600 requests in a row succeeded. > > The fix is to use the constant, as the comment means: > > ```diff > - shutdown(req->fd, 1); > + shutdown(req->fd, SHUT_WR); > ``` > > The _WIN32 branch has the same literal. > SD_SEND would be the matching name there, though > 1 is correct on Windows. > > I know WASI is not a target PHP supports. I am reporting it because the change is one line, it > says what the comment already says, and it costs nothing on the supported platforms. I can send a PR > if that is welcome. > > ### PHP Version > > ``` > PHP 8.6.0RC3 > ``` > > The same literal is on master, PHP-8.6, PHP-8.5 and PHP-8.4 as of 2026-10-10. > > ### Operating System > > Only with WASI (wasm32-wasip1, built with wasi-sdk 34), here on > Linux. Not reproducible on native builds.