Mercurial > hg > nginx-quic
view src/os/unix/ngx_file_aio_read.c @ 8743:5d09596909c6 stable-1.20
Upstream: fixed timeouts with gRPC, SSL and select (ticket #2229).
With SSL it is possible that an established connection is ready for
reading after the handshake. Further, events might be already disabled
in case of level-triggered event methods. If this happens and
ngx_http_upstream_send_request() blocks waiting for some data from
the upstream, such as flow control in case of gRPC, the connection
will time out due to no read events on the upstream connection.
Fix is to explicitly check the c->read->ready flag if sending request
blocks and post a read event if it is set.
Note that while it is possible to modify ngx_ssl_handshake() to keep
read events active, this won't completely resolve the issue, since
there can be data already received during the SSL handshake
(see 573bd30e46b4).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 20 Aug 2021 03:53:56 +0300 |
parents | 7f035fd1ec7b |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> /* * FreeBSD file AIO features and quirks: * * if an asked data are already in VM cache, then aio_error() returns 0, * and the data are already copied in buffer; * * aio_read() preread in VM cache as minimum 16K (probably BKVASIZE); * the first AIO preload may be up to 128K; * * aio_read/aio_error() may return EINPROGRESS for just written data; * * kqueue EVFILT_AIO filter is level triggered only: an event repeats * until aio_return() will be called; * * aio_cancel() cannot cancel file AIO: it returns AIO_NOTCANCELED always. */ extern int ngx_kqueue; static ssize_t ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio, ngx_event_t *ev); static void ngx_file_aio_event_handler(ngx_event_t *ev); ngx_int_t ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool) { ngx_event_aio_t *aio; aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t)); if (aio == NULL) { return NGX_ERROR; } aio->file = file; aio->fd = file->fd; aio->event.data = aio; aio->event.ready = 1; aio->event.log = file->log; file->aio = aio; return NGX_OK; } ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset, ngx_pool_t *pool) { int n; ngx_event_t *ev; ngx_event_aio_t *aio; if (!ngx_file_aio) { return ngx_read_file(file, buf, size, offset); } if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) { return NGX_ERROR; } aio = file->aio; ev = &aio->event; if (!ev->ready) { ngx_log_error(NGX_LOG_ALERT, file->log, 0, "second aio post for \"%V\"", &file->name); return NGX_AGAIN; } ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0, "aio complete:%d @%O:%uz %V", ev->complete, offset, size, &file->name); if (ev->complete) { ev->complete = 0; ngx_set_errno(aio->err); if (aio->err == 0) { return aio->nbytes; } ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno, "aio read \"%s\" failed", file->name.data); return NGX_ERROR; } ngx_memzero(&aio->aiocb, sizeof(struct aiocb)); aio->aiocb.aio_fildes = file->fd; aio->aiocb.aio_offset = offset; aio->aiocb.aio_buf = buf; aio->aiocb.aio_nbytes = size; #if (NGX_HAVE_KQUEUE) aio->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue; aio->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT; aio->aiocb.aio_sigevent.sigev_value.sival_ptr = ev; #endif ev->handler = ngx_file_aio_event_handler; n = aio_read(&aio->aiocb); if (n == -1) { n = ngx_errno; if (n == NGX_EAGAIN) { return ngx_read_file(file, buf, size, offset); } ngx_log_error(NGX_LOG_CRIT, file->log, n, "aio_read(\"%V\") failed", &file->name); if (n == NGX_ENOSYS) { ngx_file_aio = 0; return ngx_read_file(file, buf, size, offset); } return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_read: fd:%d %d", file->fd, n); ev->active = 1; ev->ready = 0; ev->complete = 0; return ngx_file_aio_result(aio->file, aio, ev); } static ssize_t ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio, ngx_event_t *ev) { int n; ngx_err_t err; n = aio_error(&aio->aiocb); ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_error: fd:%d %d", file->fd, n); if (n == -1) { err = ngx_errno; aio->err = err; ngx_log_error(NGX_LOG_ALERT, file->log, err, "aio_error(\"%V\") failed", &file->name); return NGX_ERROR; } if (n == NGX_EINPROGRESS) { if (ev->ready) { ev->ready = 0; ngx_log_error(NGX_LOG_ALERT, file->log, n, "aio_read(\"%V\") still in progress", &file->name); } return NGX_AGAIN; } n = aio_return(&aio->aiocb); if (n == -1) { err = ngx_errno; aio->err = err; ev->ready = 1; ngx_log_error(NGX_LOG_CRIT, file->log, err, "aio_return(\"%V\") failed", &file->name); return NGX_ERROR; } aio->err = 0; aio->nbytes = n; ev->ready = 1; ev->active = 0; ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_return: fd:%d %d", file->fd, n); return n; } static void ngx_file_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; aio = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0, "aio event handler fd:%d %V", aio->fd, &aio->file->name); if (ngx_file_aio_result(aio->file, aio, ev) != NGX_AGAIN) { aio->handler(ev); } }