view src/os/unix/ngx_socket.h @ 8018:5119c8150478

Fixed runtime handling of systems without EPOLLRDHUP support. In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP support in the kernel (but with EPOLLRDHUP in headers) was broken. Before the change, rev->available was never set to 0 unless ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP introduced in 6536:f7849bfb6d21 succeeded). After the change, rev->available might reach 0 on systems without runtime EPOLLRDHUP support, stopping further reading in ngx_readv_chain() and ngx_unix_recv(). And, if EOF happened to be already reported along with the last event, it is not reported again by epoll_wait(), leading to connection hangs and timeouts on such systems. This affects Linux kernels before 2.6.17 if nginx was compiled with newer headers, and, more importantly, emulation layers, such as DigitalOcean's App Platform's / gVisor's epoll emulation layer. Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author Marcus Ball <marcus.ball@live.com>
date Mon, 30 May 2022 02:38:07 +0300
parents efd71d49bde0
children 23880e4ad3e2
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_SOCKET_H_INCLUDED_
#define _NGX_SOCKET_H_INCLUDED_


#include <ngx_config.h>


#define NGX_WRITE_SHUTDOWN SHUT_WR

typedef int  ngx_socket_t;

#define ngx_socket          socket
#define ngx_socket_n        "socket()"


#if (NGX_HAVE_FIONBIO)

int ngx_nonblocking(ngx_socket_t s);
int ngx_blocking(ngx_socket_t s);

#define ngx_nonblocking_n   "ioctl(FIONBIO)"
#define ngx_blocking_n      "ioctl(!FIONBIO)"

#else

#define ngx_nonblocking(s)  fcntl(s, F_SETFL, fcntl(s, F_GETFL) | O_NONBLOCK)
#define ngx_nonblocking_n   "fcntl(O_NONBLOCK)"

#define ngx_blocking(s)     fcntl(s, F_SETFL, fcntl(s, F_GETFL) & ~O_NONBLOCK)
#define ngx_blocking_n      "fcntl(!O_NONBLOCK)"

#endif

#if (NGX_HAVE_FIONREAD)

#define ngx_socket_nread(s, n)  ioctl(s, FIONREAD, n)
#define ngx_socket_nread_n      "ioctl(FIONREAD)"

#endif

int ngx_tcp_nopush(ngx_socket_t s);
int ngx_tcp_push(ngx_socket_t s);

#if (NGX_LINUX)

#define ngx_tcp_nopush_n   "setsockopt(TCP_CORK)"
#define ngx_tcp_push_n     "setsockopt(!TCP_CORK)"

#else

#define ngx_tcp_nopush_n   "setsockopt(TCP_NOPUSH)"
#define ngx_tcp_push_n     "setsockopt(!TCP_NOPUSH)"

#endif


#define ngx_shutdown_socket    shutdown
#define ngx_shutdown_socket_n  "shutdown()"

#define ngx_close_socket    close
#define ngx_close_socket_n  "close() socket"


#endif /* _NGX_SOCKET_H_INCLUDED_ */