ngx_event_pipe.c

来自「Nginx是一个高性能的HTTP和反向代理服务器」· C语言 代码 · 共 979 行 · 第 1/2 页

/*
 * Copyright (C) Igor Sysoev
 */


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


static ngx_int_t ngx_event_pipe_read_upstream(ngx_event_pipe_t *p);
static ngx_int_t ngx_event_pipe_write_to_downstream(ngx_event_pipe_t *p);

static ngx_int_t ngx_event_pipe_write_chain_to_temp_file(ngx_event_pipe_t *p);
static ngx_inline void ngx_event_pipe_remove_shadow_links(ngx_buf_t *buf);
static ngx_inline void ngx_event_pipe_free_shadow_raw_buf(ngx_chain_t **free,
                                                          ngx_buf_t *buf);
static ngx_int_t ngx_event_pipe_drain_chains(ngx_event_pipe_t *p);


ngx_int_t
ngx_event_pipe(ngx_event_pipe_t *p, ngx_int_t do_write)
{
    u_int         flags;
    ngx_event_t  *rev, *wev;

    for ( ;; ) {
        if (do_write) {
            p->log->action = "sending to client";

            if (ngx_event_pipe_write_to_downstream(p) == NGX_ABORT) {
                return NGX_ABORT;
            }
        }

        p->read = 0;
        p->upstream_blocked = 0;

        p->log->action = "reading upstream";

        if (ngx_event_pipe_read_upstream(p) == NGX_ABORT) {
            return NGX_ABORT;
        }

        if (!p->read && !p->upstream_blocked) {
            break;
        }

        do_write = 1;
    }

    if (p->upstream->fd != -1) {
        rev = p->upstream->read;

        flags = (rev->eof || rev->error) ? NGX_CLOSE_EVENT : 0;

        if (ngx_handle_read_event(rev, flags) == NGX_ERROR) {
            return NGX_ABORT;
        }

        if (rev->active && !rev->ready) {
            ngx_add_timer(rev, p->read_timeout);

        } else if (rev->timer_set) {
            ngx_del_timer(rev);
        }
    }

    if (p->downstream->fd != -1 && p->downstream->data == p->output_ctx) {
        wev = p->downstream->write;
        if (ngx_handle_write_event(wev, p->send_lowat) == NGX_ERROR) {
            return NGX_ABORT;
        }

        if (!wev->delayed) {
            if (wev->active && !wev->ready) {
                ngx_add_timer(wev, p->send_timeout);

            } else if (wev->timer_set) {
                ngx_del_timer(wev);
            }
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_event_pipe_read_upstream(ngx_event_pipe_t *p)
{
    ssize_t       n, size;
    ngx_int_t     rc;
    ngx_buf_t    *b;
    ngx_chain_t  *chain, *cl, *ln;

    if (p->upstream_eof || p->upstream_error || p->upstream_done) {
        return NGX_OK;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                   "pipe read upstream: %d", p->upstream->read->ready);

    for ( ;; ) {

        if (p->upstream_eof || p->upstream_error || p->upstream_done) {
            break;
        }

        if (p->preread_bufs == NULL && !p->upstream->read->ready) {
            break;
        }

        if (p->preread_bufs) {

            /* use the pre-read bufs if they exist */

            chain = p->preread_bufs;
            p->preread_bufs = NULL;
            n = p->preread_size;

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                           "pipe preread: %z", n);

            if (n) {
                p->read = 1;
            }

        } else {

#if (NGX_HAVE_KQUEUE)

            /*
             * kqueue notifies about the end of file or a pending error.
             * This test allows not to allocate a buf on these conditions
             * and not to call c->recv_chain().
             */

            if (p->upstream->read->available == 0
                && p->upstream->read->pending_eof)
            {
                p->upstream->read->ready = 0;
                p->upstream->read->eof = 0;
                p->upstream_eof = 1;
                p->read = 1;

                if (p->upstream->read->kq_errno) {
                    p->upstream->read->error = 1;
                    p->upstream_error = 1;
                    p->upstream_eof = 0;

                    ngx_log_error(NGX_LOG_ERR, p->log,
                                  p->upstream->read->kq_errno,
                                  "kevent() reported that upstream "
                                  "closed connection");
                }

                break;
            }
#endif

            if (p->free_raw_bufs) {

                /* use the free bufs if they exist */

                chain = p->free_raw_bufs;
                if (p->single_buf) {
                    p->free_raw_bufs = p->free_raw_bufs->next;
                    chain->next = NULL;
                } else {
                    p->free_raw_bufs = NULL;
                }

            } else if (p->allocated < p->bufs.num) {

                /* allocate a new buf if it's still allowed */

                b = ngx_create_temp_buf(p->pool, p->bufs.size);
                if (b == NULL) {
                    return NGX_ABORT;
                }

                p->allocated++;

                chain = ngx_alloc_chain_link(p->pool);
                if (chain == NULL) {
                    return NGX_ABORT;
                }

                chain->buf = b;
                chain->next = NULL;

            } else if (!p->cacheable
                       && p->downstream->data == p->output_ctx
                       && p->downstream->write->ready
                       && !p->downstream->write->delayed)
            {
                /*
                 * if the bufs are not needed to be saved in a cache and
                 * a downstream is ready then write the bufs to a downstream
                 */

                p->upstream_blocked = 1;

                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
                               "pipe downstream ready");

                break;

            } else if (p->cacheable
                       || p->temp_file->offset < p->max_temp_file_size)
            {

                /*
                 * if it is allowed, then save some bufs from r->in
                 * to a temporary file, and add them to a r->out chain
                 */

                rc = ngx_event_pipe_write_chain_to_temp_file(p);

                ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                               "pipe temp offset: %O", p->temp_file->offset);

                if (rc == NGX_BUSY) {
                    break;
                }

                if (rc == NGX_AGAIN) {
                    if (ngx_event_flags & NGX_USE_LEVEL_EVENT
                        && p->upstream->read->active
                        && p->upstream->read->ready)
                    {
                        if (ngx_del_event(p->upstream->read, NGX_READ_EVENT, 0)
                            == NGX_ERROR)
                        {
                            return NGX_ABORT;
                        }
                    }
                }

                if (rc != NGX_OK) {
                    return rc;
                }

                chain = p->free_raw_bufs;
                if (p->single_buf) {
                    p->free_raw_bufs = p->free_raw_bufs->next;
                    chain->next = NULL;
                } else {
                    p->free_raw_bufs = NULL;
                }

            } else {

                /* there are no bufs to read in */

                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
                               "no pipe bufs to read in");

                break;
            }

            n = p->upstream->recv_chain(p->upstream, chain);

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                           "pipe recv chain: %z", n);

            if (p->free_raw_bufs) {
                chain->next = p->free_raw_bufs;
            }
            p->free_raw_bufs = chain;

            if (n == NGX_ERROR) {
                p->upstream_error = 1;
                return NGX_ERROR;
            }

            if (n == NGX_AGAIN) {
                if (p->single_buf) {
                    ngx_event_pipe_remove_shadow_links(chain->buf);
                }

                break;
            }

            p->read = 1;

            if (n == 0) {
                p->upstream_eof = 1;
                break;
            }
        }

        p->read_length += n;
        cl = chain;
        p->free_raw_bufs = NULL;

        while (cl && n > 0) {

            ngx_event_pipe_remove_shadow_links(cl->buf);

            size = cl->buf->end - cl->buf->last;

            if (n >= size) {
                cl->buf->last = cl->buf->end;

                /* STUB */ cl->buf->num = p->num++;

                if (p->input_filter(p, cl->buf) == NGX_ERROR) {
                    return NGX_ABORT;
                }

                n -= size;
                ln = cl;
                cl = cl->next;
                ngx_free_chain(p->pool, ln);

            } else {
                cl->buf->last += n;
                n = 0;
            }
        }

        if (cl) {
            for (ln = cl; ln->next; ln = ln->next) { /* void */ }

            ln->next = p->free_raw_bufs;
            p->free_raw_bufs = cl;
        }
    }

#if (NGX_DEBUG)

    for (cl = p->busy; cl; cl = cl->next) {
        ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
                       "pipe buf busy s:%d t:%d f:%d "
                       "%p, pos %p, size: %z "
                       "file: %O, size: %z",
                       (cl->buf->shadow ? 1 : 0),
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);
    }

    for (cl = p->out; cl; cl = cl->next) {
        ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
                       "pipe buf out  s:%d t:%d f:%d "
                       "%p, pos %p, size: %z "
                       "file: %O, size: %z",
                       (cl->buf->shadow ? 1 : 0),
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);
    }

    for (cl = p->in; cl; cl = cl->next) {
        ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
                       "pipe buf in   s:%d t:%d f:%d "
                       "%p, pos %p, size: %z "
                       "file: %O, size: %z",
                       (cl->buf->shadow ? 1 : 0),
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);
    }

    for (cl = p->free_raw_bufs; cl; cl = cl->next) {
        ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
                       "pipe buf free s:%d t:%d f:%d "
                       "%p, pos %p, size: %z "
                       "file: %O, size: %z",
                       (cl->buf->shadow ? 1 : 0),
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);
    }

#endif

    if ((p->upstream_eof || p->upstream_error) && p->free_raw_bufs) {

        /* STUB */ p->free_raw_bufs->buf->num = p->num++;

        if (p->input_filter(p, p->free_raw_bufs->buf) == NGX_ERROR) {
            return NGX_ABORT;
        }

        p->free_raw_bufs = p->free_raw_bufs->next;

        if (p->free_bufs) {
            for (cl = p->free_raw_bufs; cl; cl = cl->next) {
                if (cl->buf->shadow == NULL) {
                    ngx_pfree(p->pool, cl->buf->start);
                }
            }
        }
    }

    if (p->cacheable && p->in) {
        if (ngx_event_pipe_write_chain_to_temp_file(p) == NGX_ABORT) {
            return NGX_ABORT;
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_event_pipe_write_to_downstream(ngx_event_pipe_t *p)
{
    u_char            *prev;
    size_t             bsize;
    ngx_int_t          rc;
    ngx_uint_t         flush, prev_last_shadow;
    ngx_chain_t       *out, **ll, *cl;
    ngx_connection_t  *downstream;

    downstream = p->downstream;

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                   "pipe write downstream: %d", downstream->write->ready);

    for ( ;; ) {
        if (p->downstream_error) {
            return ngx_event_pipe_drain_chains(p);
        }

        if (p->upstream_eof || p->upstream_error || p->upstream_done) {

            /* pass the p->out and p->in chains to the output filter */

            for (cl = p->busy; cl; cl = cl->next) {
                cl->buf->recycled = 0;
            }

            if (p->out) {
                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
                               "pipe write downstream flush out");

                for (cl = p->out; cl; cl = cl->next) {
                    cl->buf->recycled = 0;
                }

                rc = p->output_filter(p->output_ctx, p->out);

                if (downstream->destroyed) {
                    return NGX_ABORT;
                }

                if (rc == NGX_ERROR) {
                    p->downstream_error = 1;
                    return ngx_event_pipe_drain_chains(p);
                }

                p->out = NULL;
            }

            if (p->in) {
                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
                               "pipe write downstream flush in");

                for (cl = p->in; cl; cl = cl->next) {
                    cl->buf->recycled = 0;
                }

                rc = p->output_filter(p->output_ctx, p->in);

                if (downstream->destroyed) {
                    return NGX_ABORT;
                }

                if (rc == NGX_ERROR) {
                    p->downstream_error = 1;
                    return ngx_event_pipe_drain_chains(p);
                }

                p->in = NULL;
            }