view src/os/unix/ngx_writev_chain.c @ 5914:4dd67e5d958e

Refactored ngx_solaris_sendfilev_chain(). Though ngx_solaris_sendfilev_chain() shouldn't suffer from the problem mentioned in d1bde5c3c5d2 since currently IOV_MAX on Solaris is 16, but this follows the change from 3d5717550371 in order to make the code look similar to other systems and potentially eliminates the problem in the future.
author Valentin Bartenev <vbart@nginx.com>
date Wed, 19 Nov 2014 21:17:11 +0300
parents 8e903522c17a
children 2c64b69daec5
line wrap: on
line source


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


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


ngx_chain_t *
ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
{
    ssize_t        n, sent;
    off_t          send, prev_send;
    ngx_uint_t     eintr;
    ngx_err_t      err;
    ngx_chain_t   *cl;
    ngx_event_t   *wev;
    ngx_iovec_t    vec;
    struct iovec   iovs[NGX_IOVS_PREALLOCATE];

    wev = c->write;

    if (!wev->ready) {
        return in;
    }

#if (NGX_HAVE_KQUEUE)

    if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) {
        (void) ngx_connection_error(c, wev->kq_errno,
                               "kevent() reported about an closed connection");
        wev->error = 1;
        return NGX_CHAIN_ERROR;
    }

#endif

    /* the maximum limit size is the maximum size_t value - the page size */

    if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) {
        limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize;
    }

    send = 0;

    vec.iovs = iovs;
    vec.nalloc = NGX_IOVS_PREALLOCATE;

    for ( ;; ) {
        eintr = 0;
        prev_send = send;

        /* create the iovec and coalesce the neighbouring bufs */

        cl = ngx_output_chain_to_iovec(&vec, in, limit - send, c->log);

        if (cl == NGX_CHAIN_ERROR) {
            return NGX_CHAIN_ERROR;
        }

        if (cl && cl->buf->in_file) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "file buf in writev "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          cl->buf->temporary,
                          cl->buf->recycled,
                          cl->buf->in_file,
                          cl->buf->start,
                          cl->buf->pos,
                          cl->buf->last,
                          cl->buf->file,
                          cl->buf->file_pos,
                          cl->buf->file_last);

            ngx_debug_point();

            return NGX_CHAIN_ERROR;
        }

        send += vec.size;

        n = writev(c->fd, vec.iovs, vec.count);

        if (n == -1) {
            err = ngx_errno;

            switch (err) {
            case NGX_EAGAIN:
                break;

            case NGX_EINTR:
                eintr = 1;
                break;

            default:
                wev->error = 1;
                (void) ngx_connection_error(c, err, "writev() failed");
                return NGX_CHAIN_ERROR;
            }

            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
                           "writev() not ready");
        }

        sent = n > 0 ? n : 0;

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "writev: %z", sent);

        c->sent += sent;

        in = ngx_chain_update_sent(in, sent);

        if (eintr) {
            send = prev_send;
            continue;
        }

        if (send - prev_send != sent) {
            wev->ready = 0;
            return in;
        }

        if (send >= limit || in == NULL) {
            return in;
        }
    }
}


ngx_chain_t *
ngx_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, size_t limit,
    ngx_log_t *log)
{
    size_t         total, size;
    u_char        *prev;
    ngx_uint_t     n;
    struct iovec  *iov;

    iov = NULL;
    prev = NULL;
    total = 0;
    n = 0;

    for ( /* void */ ; in && total < limit; in = in->next) {

        if (ngx_buf_special(in->buf)) {
            continue;
        }

        if (in->buf->in_file) {
            break;
        }

        if (!ngx_buf_in_memory(in->buf)) {
            ngx_log_error(NGX_LOG_ALERT, log, 0,
                          "bad buf in output chain "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          in->buf->temporary,
                          in->buf->recycled,
                          in->buf->in_file,
                          in->buf->start,
                          in->buf->pos,
                          in->buf->last,
                          in->buf->file,
                          in->buf->file_pos,
                          in->buf->file_last);

            ngx_debug_point();

            return NGX_CHAIN_ERROR;
        }

        size = in->buf->last - in->buf->pos;

        if (size > limit - total) {
            size = limit - total;
        }

        if (prev == in->buf->pos) {
            iov->iov_len += size;

        } else {
            if (n == vec->nalloc) {
                break;
            }

            iov = &vec->iovs[n++];

            iov->iov_base = (void *) in->buf->pos;
            iov->iov_len = size;
        }

        prev = in->buf->pos + size;
        total += size;
    }

    vec->count = n;
    vec->size = total;

    return in;
}