view src/os/unix/ngx_thread_id.c @ 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 466bd63b63d1
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


#if (NGX_LINUX)

/*
 * Linux thread id is a pid of thread created by clone(2),
 * glibc does not provide a wrapper for gettid().
 */

ngx_tid_t
ngx_thread_tid(void)
{
    return syscall(SYS_gettid);
}

#elif (NGX_FREEBSD) && (__FreeBSD_version >= 900031)

#include <pthread_np.h>

ngx_tid_t
ngx_thread_tid(void)
{
    return pthread_getthreadid_np();
}

#elif (NGX_DARWIN)

/*
 * MacOSX thread has two thread ids:
 *
 * 1) MacOSX 10.6 (Snow Leoprad) has pthread_threadid_np() returning
 *    an uint64_t value, which is obtained using the __thread_selfid()
 *    syscall.  It is a number above 300,000.
 */

ngx_tid_t
ngx_thread_tid(void)
{
    uint64_t  tid;

    (void) pthread_threadid_np(NULL, &tid);
    return tid;
}

/*
 * 2) Kernel thread mach_port_t returned by pthread_mach_thread_np().
 *    It is a number in range 100-100,000.
 *
 * return pthread_mach_thread_np(pthread_self());
 */

#else

ngx_tid_t
ngx_thread_tid(void)
{
    return (uint64_t) (uintptr_t) pthread_self();
}

#endif