view src/os/unix/ngx_socket.c @ 8106:8852f39311de

Fixed segfault when switching off master process during upgrade. Binary upgrades are not supported without master process, but it is, however, possible, that nginx running with master process is asked to upgrade binary, and the configuration file as available on disk at this time includes "master_process off;". If this happens, listening sockets inherited from the previous binary will have ls[i].previous set. But the old cycle on initial process startup, including startup after binary upgrade, is destroyed by ngx_init_cycle() once configuration parsing is complete. As a result, an attempt to dereference ls[i].previous in ngx_event_process_init() accesses already freed memory. Fix is to avoid looking into ls[i].previous if the old cycle is already freed. With this change it is also no longer needed to clear ls[i].previous in worker processes, so the relevant code was removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Nov 2022 23:48:53 +0300
parents d620f497c50f
children
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


/*
 * ioctl(FIONBIO) sets a non-blocking mode with the single syscall
 * while fcntl(F_SETFL, O_NONBLOCK) needs to learn the current state
 * using fcntl(F_GETFL).
 *
 * ioctl() and fcntl() are syscalls at least in FreeBSD 2.x, Linux 2.2
 * and Solaris 7.
 *
 * ioctl() in Linux 2.4 and 2.6 uses BKL, however, fcntl(F_SETFL) uses it too.
 */


#if (NGX_HAVE_FIONBIO)

int
ngx_nonblocking(ngx_socket_t s)
{
    int  nb;

    nb = 1;

    return ioctl(s, FIONBIO, &nb);
}


int
ngx_blocking(ngx_socket_t s)
{
    int  nb;

    nb = 0;

    return ioctl(s, FIONBIO, &nb);
}

#endif


#if (NGX_FREEBSD)

int
ngx_tcp_nopush(ngx_socket_t s)
{
    int  tcp_nopush;

    tcp_nopush = 1;

    return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH,
                      (const void *) &tcp_nopush, sizeof(int));
}


int
ngx_tcp_push(ngx_socket_t s)
{
    int  tcp_nopush;

    tcp_nopush = 0;

    return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH,
                      (const void *) &tcp_nopush, sizeof(int));
}

#elif (NGX_LINUX)


int
ngx_tcp_nopush(ngx_socket_t s)
{
    int  cork;

    cork = 1;

    return setsockopt(s, IPPROTO_TCP, TCP_CORK,
                      (const void *) &cork, sizeof(int));
}


int
ngx_tcp_push(ngx_socket_t s)
{
    int  cork;

    cork = 0;

    return setsockopt(s, IPPROTO_TCP, TCP_CORK,
                      (const void *) &cork, sizeof(int));
}

#else

int
ngx_tcp_nopush(ngx_socket_t s)
{
    return 0;
}


int
ngx_tcp_push(ngx_socket_t s)
{
    return 0;
}

#endif