static ngx_int_t ngx_http_replace_output(ngx_http_request_t *r, ngx_http_replace_ctx_t *ctx) { ngx_int_t rc; ngx_buf_t *b; ngx_chain_t *cl; #if (DDEBUG) b = NULL; for (cl = ctx->out; cl; cl = cl->next) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "replace out: %p %p", cl->buf, cl->buf->pos); if (cl->buf == b) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "the same buf was used in sub"); ngx_debug_point(); return NGX_ERROR; } b = cl->buf; } /* ngx_http_replace_dump_chain("ctx->out", &ctx->out, ctx->last_out); */ #endif rc = ngx_http_next_body_filter(r, ctx->out); /* we are essentially duplicating the logic of * ngx_chain_update_chains below, * with our own optimizations */ if (ctx->busy == NULL) { ctx->busy = ctx->out; } else { for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ } cl->next = ctx->out; } ctx->out = NULL; ctx->last_out = &ctx->out; while (ctx->busy) { cl = ctx->busy; b = cl->buf; if (ngx_buf_size(b) != 0) { break; } if (cl->buf->tag != (ngx_buf_tag_t) &ngx_http_replace_filter_module) { ctx->busy = cl->next; ngx_free_chain(r->pool, cl); continue; } if (b->shadow) { b->shadow->pos = b->shadow->last; b->shadow->file_pos = b->shadow->file_last; } ctx->busy = cl->next; if (ngx_buf_special(b)) { /* collect special bufs to ctx->special, which may still be busy */ cl->next = NULL; *ctx->last_special = cl; ctx->last_special = &cl->next; } else { /* add ctx->special to ctx->free because they cannot be busy at * this point */ *ctx->last_special = ctx->free; ctx->free = ctx->special; ctx->special = NULL; ctx->last_special = &ctx->special; #if 0 /* free the temporary buf's data block if it is big enough */ if (b->temporary && b->start != NULL && b->end - b->start > (ssize_t) r->pool->max) { ngx_pfree(r->pool, b->start); } #endif /* add the data buf itself to the free buf chain */ cl->next = ctx->free; ctx->free = cl; } } if (ctx->in || ctx->buf) { r->buffered |= NGX_HTTP_SUB_BUFFERED; } else { r->buffered &= ~NGX_HTTP_SUB_BUFFERED; } return rc; }
ngx_int_t ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in) { off_t size, sent, nsent, limit; ngx_uint_t last, flush, sync; ngx_msec_t delay; ngx_chain_t *cl, *ln, **ll, *chain; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; c = r->connection; if (c->error) { return NGX_ERROR; } size = 0; flush = 0; sync = 0; last = 0; ll = &r->out; /* find the size, the flush point and the last link of the saved chain */ for (cl = r->out; cl; cl = cl->next) { ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write old buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", 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); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } /* add the new chain to the existent one */ for (ln = in; ln; ln = ln->next) { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ln->buf; *ll = cl; ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write new buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", 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); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } *ll = NULL; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter: l:%d f:%d s:%O", last, flush, size); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); /* * avoid the output if there are no last buf, no flush point, * there are the incoming bufs and the size of all bufs * is smaller than "postpone_output" directive */ if (!last && !flush && in && size < (off_t) clcf->postpone_output) { return NGX_OK; } if (c->write->delayed) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (size == 0 && !(c->buffered & NGX_LOWLEVEL_BUFFERED) && !(last && c->need_last_buf)) { if (last || flush || sync) { for (cl = r->out; cl; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = NULL; c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, c->log, 0, "the http output chain is empty"); ngx_debug_point(); return NGX_ERROR; } if (r->limit_rate) { if (r->limit_rate_after == 0) { r->limit_rate_after = clcf->limit_rate_after; } limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1) - (c->sent - r->limit_rate_after); if (limit <= 0) { c->write->delayed = 1; delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1); ngx_add_timer(c->write, delay); c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (clcf->sendfile_max_chunk && (off_t) clcf->sendfile_max_chunk < limit) { limit = clcf->sendfile_max_chunk; } } else { limit = clcf->sendfile_max_chunk; } sent = c->sent; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter limit %O", limit); chain = c->send_chain(c, r->out, limit); if (ngx_http_log_flow && ngx_http_log_flow(r) == NGX_ERROR) { return NGX_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter %p", chain); if (chain == NGX_CHAIN_ERROR) { c->error = 1; return NGX_ERROR; } if (r->limit_rate) { nsent = c->sent; if (r->limit_rate_after) { sent -= r->limit_rate_after; if (sent < 0) { sent = 0; } nsent -= r->limit_rate_after; if (nsent < 0) { nsent = 0; } } delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate); if (delay > 0) { limit = 0; c->write->delayed = 1; ngx_add_timer(c->write, delay); } } if (limit && c->write->ready && c->sent - sent >= limit - (off_t) (2 * ngx_pagesize)) { c->write->delayed = 1; ngx_add_timer(c->write, 1); } for (cl = r->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = chain; if (chain) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) { return NGX_AGAIN; } return NGX_OK; }
ngx_int_t ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in) { off_t bsize; ngx_int_t rc, last; ngx_chain_t *cl, *out, **last_out; if (ctx->in == NULL && ctx->busy == NULL) { /* * the short path for the case when the ctx->in and ctx->busy chains * are empty, the incoming chain is empty too or has the single buf * that does not require the copy */ if (in == NULL) { return ctx->output_filter(ctx->filter_ctx, in); } if (in->next == NULL #if (NGX_SENDFILE_LIMIT) && !(in->buf->in_file && in->buf->file_last > NGX_SENDFILE_LIMIT) #endif && ngx_output_chain_as_is(ctx, in->buf)) { return ctx->output_filter(ctx->filter_ctx, in); } } /* add the incoming buf to the chain ctx->in */ if (in) { if (ngx_output_chain_add_copy(ctx->pool, &ctx->in, in) == NGX_ERROR) { return NGX_ERROR; } } #if (NGX_HAVE_FILE_AIO) if (ctx->aio) { return NGX_AGAIN; } #endif out = NULL; last_out = &out; last = NGX_NONE; for ( ;; ) { while (ctx->in) { /* * cycle while there are the ctx->in bufs * and there are the free output bufs to copy in */ bsize = ngx_buf_size(ctx->in->buf); if (bsize == 0 && !ngx_buf_special(ctx->in->buf)) { ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0, "zero size buf in output " "t:%d r:%d f:%d %p %p-%p %p %O-%O", ctx->in->buf->temporary, ctx->in->buf->recycled, ctx->in->buf->in_file, ctx->in->buf->start, ctx->in->buf->pos, ctx->in->buf->last, ctx->in->buf->file, ctx->in->buf->file_pos, ctx->in->buf->file_last); ngx_debug_point(); ctx->in = ctx->in->next; continue; } if (ngx_output_chain_as_is(ctx, ctx->in->buf)) { /* move the chain link to the output chain */ cl = ctx->in; ctx->in = cl->next; *last_out = cl; last_out = &cl->next; cl->next = NULL; continue; } if (ctx->buf == NULL) { rc = ngx_output_chain_align_file_buf(ctx, bsize); if (rc == NGX_ERROR) { return NGX_ERROR; } if (rc != NGX_OK) { if (ctx->free) { /* get the free buf */ cl = ctx->free; ctx->buf = cl->buf; ctx->free = cl->next; ngx_free_chain(ctx->pool, cl); } else if (out || ctx->allocated == ctx->bufs.num) { break; } else if (ngx_output_chain_get_buf(ctx, bsize) != NGX_OK) { return NGX_ERROR; } } } rc = ngx_output_chain_copy_buf(ctx); if (rc == NGX_ERROR) { return rc; } if (rc == NGX_AGAIN) { if (out) { break; } return rc; } /* delete the completed buf from the ctx->in chain */ if (ngx_buf_size(ctx->in->buf) == 0) { ctx->in = ctx->in->next; } cl = ngx_alloc_chain_link(ctx->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ctx->buf; cl->next = NULL; *last_out = cl; last_out = &cl->next; ctx->buf = NULL; } if (out == NULL && last != NGX_NONE) { if (ctx->in) { return NGX_AGAIN; } return last; } last = ctx->output_filter(ctx->filter_ctx, out); if (last == NGX_ERROR || last == NGX_DONE) { return last; } ngx_chain_update_chains(&ctx->free, &ctx->busy, &out, ctx->tag); last_out = &out; } }
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 && p->buf_to_file == NULL) { 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_http_v2_data_frame_handler(ngx_http_v2_connection_t *h2c, ngx_http_v2_out_frame_t *frame) { ngx_buf_t *buf; ngx_chain_t *cl, *ln; ngx_http_v2_stream_t *stream; stream = frame->stream; cl = frame->first; if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_module) { if (cl->buf->pos != cl->buf->last) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2:%ui DATA frame %p was sent partially", stream->node->id, frame); return NGX_AGAIN; } ln = cl->next; cl->next = stream->free_frame_headers; stream->free_frame_headers = cl; if (cl == frame->last) { goto done; } cl = ln; } for ( ;; ) { if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) { buf = cl->buf->shadow; if (ngx_buf_in_memory(buf)) { buf->pos = cl->buf->pos; } if (buf->in_file) { buf->file_pos = cl->buf->file_pos; } } if (ngx_buf_size(cl->buf) != 0) { if (cl != frame->first) { frame->first = cl; ngx_http_v2_handle_stream(h2c, stream); } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2:%ui DATA frame %p was sent partially", stream->node->id, frame); return NGX_AGAIN; } ln = cl->next; if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) { cl->next = stream->free_bufs; stream->free_bufs = cl; } else { ngx_free_chain(stream->request->pool, cl); } if (cl == frame->last) { goto done; } cl = ln; } done: ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2:%ui DATA frame %p was sent", stream->node->id, frame); stream->request->header_size += NGX_HTTP_V2_FRAME_HEADER_SIZE; ngx_http_v2_handle_frame(stream, frame); ngx_http_v2_handle_stream(h2c, stream); return NGX_OK; }
static ngx_chain_t * ngx_http_v2_send_chain(ngx_connection_t *fc, ngx_chain_t *in, off_t limit) { off_t size, offset; size_t rest, frame_size; ngx_chain_t *cl, *out, **ln; ngx_http_request_t *r; ngx_http_v2_stream_t *stream; ngx_http_v2_loc_conf_t *h2lcf; ngx_http_v2_out_frame_t *frame; ngx_http_v2_connection_t *h2c; r = fc->data; stream = r->stream; #if (NGX_SUPPRESS_WARN) size = 0; #endif while (in) { size = ngx_buf_size(in->buf); if (size || in->buf->last_buf) { break; } in = in->next; } if (in == NULL) { if (stream->queued) { fc->write->active = 1; fc->write->ready = 0; } else { fc->buffered &= ~NGX_HTTP_V2_BUFFERED; } return NULL; } h2c = stream->connection; if (size && ngx_http_v2_flow_control(h2c, stream) == NGX_DECLINED) { fc->write->active = 1; fc->write->ready = 0; return in; } if (in->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_CHAIN_ERROR; } cl->buf = in->buf; in->buf = cl->buf->shadow; offset = ngx_buf_in_memory(in->buf) ? (cl->buf->pos - in->buf->pos) : (cl->buf->file_pos - in->buf->file_pos); cl->next = stream->free_bufs; stream->free_bufs = cl; } else { offset = 0; } if (limit == 0 || limit > (off_t) h2c->send_window) { limit = h2c->send_window; } if (limit > stream->send_window) { limit = (stream->send_window > 0) ? stream->send_window : 0; } h2lcf = ngx_http_get_module_loc_conf(r, ngx_http_v2_module); frame_size = (h2lcf->chunk_size < h2c->frame_size) ? h2lcf->chunk_size : h2c->frame_size; #if (NGX_SUPPRESS_WARN) cl = NULL; #endif for ( ;; ) { if ((off_t) frame_size > limit) { frame_size = (size_t) limit; } ln = &out; rest = frame_size; while ((off_t) rest >= size) { if (offset) { cl = ngx_http_v2_filter_get_shadow(stream, in->buf, offset, size); if (cl == NULL) { return NGX_CHAIN_ERROR; } offset = 0; } else { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_CHAIN_ERROR; } cl->buf = in->buf; } *ln = cl; ln = &cl->next; rest -= (size_t) size; in = in->next; if (in == NULL) { frame_size -= rest; rest = 0; break; } size = ngx_buf_size(in->buf); } if (rest) { cl = ngx_http_v2_filter_get_shadow(stream, in->buf, offset, rest); if (cl == NULL) { return NGX_CHAIN_ERROR; } cl->buf->flush = 0; cl->buf->last_buf = 0; *ln = cl; offset += rest; size -= rest; } frame = ngx_http_v2_filter_get_data_frame(stream, frame_size, out, cl); if (frame == NULL) { return NGX_CHAIN_ERROR; } ngx_http_v2_queue_frame(h2c, frame); h2c->send_window -= frame_size; stream->send_window -= frame_size; stream->queued++; if (in == NULL) { break; } limit -= frame_size; if (limit == 0) { break; } } if (offset) { cl = ngx_http_v2_filter_get_shadow(stream, in->buf, offset, size); if (cl == NULL) { return NGX_CHAIN_ERROR; } in->buf = cl->buf; ngx_free_chain(r->pool, cl); } if (ngx_http_v2_filter_send(fc, stream) == NGX_ERROR) { return NGX_CHAIN_ERROR; } if (in && ngx_http_v2_flow_control(h2c, stream) == NGX_DECLINED) { fc->write->active = 1; fc->write->ready = 0; } return in; }
void free(ngx_pool_t* pool) const { ngx_free_chain(pool, get()); }
static ngx_int_t ngx_http_spdy_data_frame_handler(ngx_http_spdy_connection_t *sc, ngx_http_spdy_out_frame_t *frame) { ngx_chain_t *cl, *ln; ngx_http_spdy_stream_t *stream; stream = frame->stream; cl = frame->first; if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_spdy_serverpush_filter_module) { if (cl->buf->pos != cl->buf->last) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0, "spdy:%ui DATA frame %p was sent partially", stream->id, frame); return NGX_AGAIN; } ln = cl->next; cl->next = stream->free_data_headers; stream->free_data_headers = cl; if (cl == frame->last) { goto done; } cl = ln; } for ( ;; ) { if (ngx_buf_size(cl->buf) != 0) { if (cl != frame->first) { frame->first = cl; ngx_http_spdy_handle_stream(sc, stream); } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0, "spdy:%ui DATA frame %p was sent partially", stream->id, frame); return NGX_AGAIN; } ln = cl->next; ngx_free_chain(stream->request->pool, cl); if (cl == frame->last) { goto done; } cl = ln; } done: ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0, "spdy:%ui DATA frame %p was sent", stream->id, frame); stream->request->header_size += NGX_SPDY_FRAME_HEADER_SIZE; ngx_http_spdy_handle_frame(stream, frame); ngx_http_spdy_handle_stream(sc, stream); return NGX_OK; }
static ngx_int_t ngx_http_write_request_body(ngx_http_request_t *r) { ssize_t n; ngx_chain_t *cl, *ln; ngx_temp_file_t *tf; ngx_http_request_body_t *rb; ngx_http_core_loc_conf_t *clcf; rb = r->request_body; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http write client request body, bufs %p", rb->bufs); if (rb->temp_file == NULL) { tf = ngx_pcalloc(r->pool, sizeof(ngx_temp_file_t)); if (tf == NULL) { return NGX_ERROR; } clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); tf->file.fd = NGX_INVALID_FILE; tf->file.log = r->connection->log; tf->path = clcf->client_body_temp_path; tf->pool = r->pool; tf->warn = "a client request body is buffered to a temporary file"; tf->log_level = r->request_body_file_log_level; tf->persistent = r->request_body_in_persistent_file; tf->clean = r->request_body_in_clean_file; if (r->request_body_file_group_access) { tf->access = 0660; } rb->temp_file = tf; if (rb->bufs == NULL) { /* empty body with r->request_body_in_file_only */ if (ngx_create_temp_file(&tf->file, tf->path, tf->pool, tf->persistent, tf->clean, tf->access) != NGX_OK) { return NGX_ERROR; } return NGX_OK; } } if (rb->bufs == NULL) { return NGX_OK; } n = ngx_write_chain_to_temp_file(rb->temp_file, rb->bufs); /* TODO: n == 0 or not complete and level event */ if (n == NGX_ERROR) { return NGX_ERROR; } rb->temp_file->offset += n; /* mark all buffers as written */ for (cl = rb->bufs; cl; /* void */) { cl->buf->pos = cl->buf->last; ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } rb->bufs = NULL; return NGX_OK; }
/* 参数r是对应的请求,in是保存本次待发送数据的链表缓冲区 */ ngx_int_t ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in) { off_t size, sent, nsent, limit; ngx_uint_t last, flush; ngx_msec_t delay; ngx_chain_t *cl, *ln, **ll, *chain; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; /* 获取当前请求所对应的连接 */ c = r->connection; /* * 检查当前连接的错误标志位error,若该标志位为1, * 表示当前请求出错,返回NGX_ERROR; */ if (c->error) { return NGX_ERROR; } size = 0; flush = 0; last = 0; ll = &r->out; /* find the size, the flush point and the last link of the saved chain */ /* * 遍历当前请求out链表缓冲区,计算剩余响应报文的长度; * 因为当响应报文一次性不能发送完成时,会把剩余的响应报文保存在out中, * 相对于本次发送的响应报文数据in来说(即该方法所传入的参数in), * out链表缓冲区保存的是前一次剩余的响应报文; */ for (cl = r->out; cl; cl = cl->next) { ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write old buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %z", 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); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->last_buf) { last = 1; } } /* add the new chain to the existent one */ /* * 将本次待发送的响应报文的缓冲区in添加到out链表缓冲区的尾部, * 并计算待发送响应报文总的长度size; */ for (ln = in; ln; ln = ln->next) { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ln->buf; *ll = cl;/* 由上面可知 ll=&r->out */ ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write new buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %z", 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); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->last_buf) { last = 1; } } *ll = NULL; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter: l:%d f:%d s:%O", last, flush, size); /* 获取ngx_http_core_module模块的loc级别配置项结构体 */ clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); /* * avoid the output if there are no last buf, no flush point, * there are the incoming bufs and the size of all bufs * is smaller than "postpone_output" directive */ /* * 若out链表最后一块缓冲区last为空,且没有强制性刷新flush链表缓冲区out, * 且当前有待发响应报文in,但是待发送响应报文总的长度size小于预设可发送条件值postpone_output, * 则本次不能发送响应报文,继续保存在out链表缓冲区中,以待下次才发送; * 其中postpone_output预设值我们可以在配置文件nginx.conf中设置; */ if (!last && !flush && in && size < (off_t) clcf->postpone_output) { return NGX_OK; } /* * 检查当前连接上写事件的delayed标志位, * 若该标志位为1,表示需要延迟发送响应报文, * 因此,返回NGX_AGAIN,表示延迟发送; */ if (c->write->delayed) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (size == 0 && !(c->buffered & NGX_LOWLEVEL_BUFFERED) && !(last && c->need_last_buf)) { if (last || flush) { for (cl = r->out; cl; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = NULL; c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, c->log, 0, "the http output chain is empty"); ngx_debug_point(); return NGX_ERROR; } /* * 检查当前请求的限速标志位limit_rate, * 若该标志位为大于0,表示发送响应报文的速度不能超过limit_rate指定的速度; */ if (r->limit_rate) { if (r->limit_rate_after == 0) { r->limit_rate_after = clcf->limit_rate_after; } /* 计算发送速度是否超过限速值 */ limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1) - (c->sent - r->limit_rate_after); /* * 若当前发送响应报文的速度超过限速值,则写事件标志位delayed设为1, * 并把该写事件添加到定时器机制中,并且将buffered设置为可写状态, * 返回NGX_AGAIN,表示链表缓冲区out还保存剩余待发送的响应报文; */ if (limit <= 0) { c->write->delayed = 1; ngx_add_timer(c->write, (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1)); c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (clcf->sendfile_max_chunk && (off_t) clcf->sendfile_max_chunk < limit) { limit = clcf->sendfile_max_chunk; } } else { limit = clcf->sendfile_max_chunk; } /* 若不需要减速,或没有设置速度限制,则向客户端发送响应字符流 */ sent = c->sent; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter limit %O", limit); chain = c->send_chain(c, r->out, limit); ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter %p", chain); if (chain == NGX_CHAIN_ERROR) { c->error = 1; return NGX_ERROR; } /* 再次检查limit_rate标志位 */ if (r->limit_rate) { nsent = c->sent; if (r->limit_rate_after) { sent -= r->limit_rate_after; if (sent < 0) { sent = 0; } nsent -= r->limit_rate_after; if (nsent < 0) { nsent = 0; } } /* 再次计算当前发送响应报文速度是否超过限制值 */ delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate); /* 若超过,需要限速,并把写事件添加到定时器机制中 */ if (delay > 0) { limit = 0; c->write->delayed = 1; ngx_add_timer(c->write, delay); } } if (limit && c->write->ready && c->sent - sent >= limit - (off_t) (2 * ngx_pagesize)) { c->write->delayed = 1; ngx_add_timer(c->write, 1); } /* 重新调整链表缓冲区out的情况,把已发送数据的缓冲区内存回收 */ for (cl = r->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } /* 检查out链表缓冲区是否还有数据 */ r->out = chain; /* 若还有数据,返回NGX_AGAIN,表示还存在待发送的响应报文数据 */ if (chain) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) { return NGX_AGAIN; } /* 若已发送全部数据则返回NGX_OK */ return NGX_OK; }
ngx_int_t ngx_chain_writer(void *data, ngx_chain_t *in) { ngx_chain_writer_ctx_t *ctx = data; off_t size; ngx_chain_t *cl, *ln, *chain; ngx_connection_t *c; c = ctx->connection; for (size = 0; in; in = in->next) { #if 1 if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) { ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0, "zero size buf in chain writer " "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(); continue; } #endif size += ngx_buf_size(in->buf); ngx_log_debug2(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer buf fl:%d s:%uO", in->buf->flush, ngx_buf_size(in->buf)); cl = ngx_alloc_chain_link(ctx->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = in->buf; cl->next = NULL; *ctx->last = cl; ctx->last = &cl->next; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer in: %p", ctx->out); for (cl = ctx->out; cl; cl = cl->next) { #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0, "zero size buf in chain writer " "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(); continue; } #endif size += ngx_buf_size(cl->buf); } if (size == 0 && !c->buffered) { return NGX_OK; } chain = c->send_chain(c, ctx->out, ctx->limit); ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer out: %p", chain); if (chain == NGX_CHAIN_ERROR) { return NGX_ERROR; } for (cl = ctx->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(ctx->pool, ln); } ctx->out = chain; if (ctx->out == NULL) { ctx->last = &ctx->out; if (!c->buffered) { return NGX_OK; } } return NGX_AGAIN; }
ngx_int_t ngx_chain_writer(void *data, ngx_chain_t *in) { ngx_chain_writer_ctx_t *ctx = data; off_t size; ngx_chain_t *cl, *ct; ngx_connection_t *c; c = ctx->connection; for (size = 0; in; in = in->next) { #if 1 if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) { ngx_debug_point(); } #endif size += ngx_buf_size(in->buf); ngx_log_debug2(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer buf fl:%d s:%uO", in->buf->flush, ngx_buf_size(in->buf)); cl = ngx_alloc_chain_link(ctx->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = in->buf; cl->next = NULL; *ctx->last = cl; ctx->last = &cl->next; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer in: %p", ctx->out); for (cl = ctx->out; cl; cl = cl->next) { #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_debug_point(); } #endif size += ngx_buf_size(cl->buf); } if (size == 0 && !c->buffered) { return NGX_OK; } cl = ctx->out; ctx->out = c->send_chain(c, ctx->out, ctx->limit); ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0, "chain writer out: %p", ctx->out); if (ctx->out == NGX_CHAIN_ERROR) { return NGX_ERROR; } while (cl != ctx->out) { ct = cl->next; ngx_free_chain(ctx->pool, cl); cl = ct; } if (ctx->out == NULL) { ctx->last = &ctx->out; if (!c->buffered) { return NGX_OK; } } return NGX_AGAIN; }
// 真正的向客户端发送数据,调用send_chain // 也由ngx_http_set_write_handler设置epoll的写事件触发 // 如果数据发送不完,就保存在r->out里,返回again // 需要再次发生可写事件才能发送 // 不是last、flush,且数据量较小(默认1460) // 那么这次就不真正调用write发送,减少系统调用的次数,提高性能 // 在此函数里处理限速 ngx_int_t ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in) { off_t size, sent, nsent, limit; ngx_uint_t last, flush, sync; ngx_msec_t delay; ngx_chain_t *cl, *ln, **ll, *chain; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; // 获取连接对象 c = r->connection; // 如果连接有错误就不能发送数据 if (c->error) { return NGX_ERROR; } // 数据的长度, size = 0; // 是否flush的标志 flush = 0; // 是否sync的标志 sync = 0; // 是否是最后一块数据,即数据全部发送完毕 last = 0; // 请求里存储的待发送的数据链表 // 可能是之前因为again而未能发送出去 ll = &r->out; /* find the size, the flush point and the last link of the saved chain */ // 先遍历当前请求里待发送的数据链表,计算长度 for (cl = r->out; cl; cl = cl->next) { ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write old buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", 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); #if 1 // 缓冲区0长度,但不是flush、sync等控制用缓冲区,报错 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif // 累计数据长度 size += ngx_buf_size(cl->buf); // flush标志 if (cl->buf->flush || cl->buf->recycled) { flush = 1; } // sync标志 if (cl->buf->sync) { sync = 1; } // 发送结束的标志 if (cl->buf->last_buf) { last = 1; } } /* add the new chain to the existent one */ // 遍历新的数据链表,计算长度 // 把in链表里的数据挂到r->out链表后面 for (ln = in; ln; ln = ln->next) { // 分配一个新的链表节点 cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } // 拷贝缓冲区,然后挂到out后面 cl->buf = ln->buf; *ll = cl; ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write new buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", 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); #if 1 // 缓冲区0长度,但不是flush、sync等控制用缓冲区,报错 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "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_ERROR; } #endif // 累计数据长度 size += ngx_buf_size(cl->buf); // flush标志 if (cl->buf->flush || cl->buf->recycled) { flush = 1; } // sync标志 if (cl->buf->sync) { sync = 1; } // 发送结束的标志 if (cl->buf->last_buf) { last = 1; } } // 链表的最后节点,必须设置为空指针 *ll = NULL; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter: l:%ui f:%ui s:%O", last, flush, size); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); /* * avoid the output if there are no last buf, no flush point, * there are the incoming bufs and the size of all bufs * is smaller than "postpone_output" directive */ // 不是last、flush,且数据量较小(默认1460) // 那么这次就不真正调用write发送,减少系统调用的次数,提高性能 if (!last && !flush && in && size < (off_t) clcf->postpone_output) { return NGX_OK; } // flush,用户要求立即发送 // last,所有的数据都集齐了,之后不会有新数据 // size > postpone_output,数据已经积累的足够多,应该发送了 // delayed表示需要限速,那么就暂不发送 if (c->write->delayed) { // 置标志位,表示连接有数据缓冲待发送 c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } // 数据长度为0 if (size == 0 && !(c->buffered & NGX_LOWLEVEL_BUFFERED) && !(last && c->need_last_buf)) { // 释放r->out里的节点 if (last || flush || sync) { for (cl = r->out; cl; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = NULL; c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, c->log, 0, "the http output chain is empty"); ngx_debug_point(); return NGX_ERROR; } // 处理限速,不研究 if (r->limit_rate) { if (r->limit_rate_after == 0) { r->limit_rate_after = clcf->limit_rate_after; } limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1) - (c->sent - r->limit_rate_after); if (limit <= 0) { c->write->delayed = 1; delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1); ngx_add_timer(c->write, delay); c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (clcf->sendfile_max_chunk && (off_t) clcf->sendfile_max_chunk < limit) { limit = clcf->sendfile_max_chunk; } } else { // 不限速,使用配置的参数,默认是0,即不限制,尽量多发 limit = clcf->sendfile_max_chunk; } // 已经发送的字节数 sent = c->sent; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter limit %O", limit); // 调用send_chain发送out链表 // 实际上调用的是ngx_writev_chain // // 发送limit长度(字节数)的数据 // 如果事件not ready,即暂不可写,那么立即返回,无动作 // 要求缓冲区必须在内存里,否则报错 // 最后返回消费缓冲区之后的链表指针 // 发送出错、遇到again、发送完毕,这三种情况函数结束 // 返回的是最后发送到的链表节点指针 chain = c->send_chain(c, r->out, limit); ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter %p", chain); if (chain == NGX_CHAIN_ERROR) { c->error = 1; return NGX_ERROR; } // 处理限速,不研究 if (r->limit_rate) { nsent = c->sent; if (r->limit_rate_after) { sent -= r->limit_rate_after; if (sent < 0) { sent = 0; } nsent -= r->limit_rate_after; if (nsent < 0) { nsent = 0; } } delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate); if (delay > 0) { limit = 0; c->write->delayed = 1; ngx_add_timer(c->write, delay); } } // 处理限速,不研究 if (limit && c->write->ready && c->sent - sent >= limit - (off_t) (2 * ngx_pagesize)) { c->write->delayed = 1; ngx_add_timer(c->write, 1); } // 在out链表里把已经发送过的节点都回收,供以后复用 for (cl = r->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } // out指向新的位置 r->out = chain; // 不是空指针,表明还有数据没发完 if (chain) { // 置标志位,表示连接有数据缓冲待发送 c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } // 已经发送完了 // 清除缓冲标志位 c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; // NGX_LOWLEVEL_BUFFERED目前似乎在nginx里还没有用到 if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) { return NGX_AGAIN; } return NGX_OK; }