src/os/unix/ngx_freebsd_sendfile_chain.c - nginx - Git at Google


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


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


 /*
  * Although FreeBSD sendfile() allows to pass a header and a trailer,
  * it cannot send a header with a part of the file in one packet until
  * FreeBSD 5.3.  Besides, over the fast ethernet connection sendfile()
  * may send the partially filled packets, i.e. the 8 file pages may be sent
  * as the 11 full 1460-bytes packets, then one incomplete 324-bytes packet,
  * and then again the 11 full 1460-bytes packets.
  *
  * Therefore we use the TCP_NOPUSH option (similar to Linux's TCP_CORK)
  * to postpone the sending - it not only sends a header and the first part of
  * the file in one packet, but also sends the file pages in the full packets.
  *
  * But until FreeBSD 4.5 turning TCP_NOPUSH off does not flush a pending
  * data that less than MSS, so that data may be sent with 5 second delay.
  * So we do not use TCP_NOPUSH on FreeBSD prior to 4.5, although it can be used
  * for non-keepalive HTTP connections.
  */


 ngx_chain_t *
 ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 {
     int              rc, flags;
     off_t            send, prev_send, sent;
     size_t           file_size;
     ssize_t          n;
     ngx_err_t        err;
     ngx_buf_t       *file;
     ngx_uint_t       eintr, eagain;
 #if (NGX_HAVE_SENDFILE_NODISKIO)
     ngx_uint_t       ebusy;
 #endif
     ngx_event_t     *wev;
     ngx_chain_t     *cl;
     ngx_iovec_t      header, trailer;
     struct sf_hdtr   hdtr;
     struct iovec     headers[NGX_IOVS_PREALLOCATE];
     struct iovec     trailers[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;
     eagain = 0;
     flags = 0;

     header.iovs = headers;
     header.nalloc = NGX_IOVS_PREALLOCATE;

     trailer.iovs = trailers;
     trailer.nalloc = NGX_IOVS_PREALLOCATE;

     for ( ;; ) {
         eintr = 0;
 #if (NGX_HAVE_SENDFILE_NODISKIO)
         ebusy = 0;
 #endif
         prev_send = send;

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

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

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

         send += header.size;

         if (cl && cl->buf->in_file && send < limit) {
             file = cl->buf;

             /* coalesce the neighbouring file bufs */

             file_size = (size_t) ngx_chain_coalesce_file(&cl, limit - send);

             send += file_size;

             if (send < limit) {

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

                 cl = ngx_output_chain_to_iovec(&trailer, cl, limit - send,
                                                c->log);
                 if (cl == NGX_CHAIN_ERROR) {
                     return NGX_CHAIN_ERROR;
                 }

                 send += trailer.size;

             } else {
                 trailer.count = 0;
             }

             if (ngx_freebsd_use_tcp_nopush
                 && c->tcp_nopush == NGX_TCP_NOPUSH_UNSET)
             {
                 if (ngx_tcp_nopush(c->fd) == -1) {
                     err = ngx_socket_errno;

                     /*
                      * there is a tiny chance to be interrupted, however,
                      * we continue a processing without the TCP_NOPUSH
                      */

                     if (err != NGX_EINTR) {
                         wev->error = 1;
                         (void) ngx_connection_error(c, err,
                                                     ngx_tcp_nopush_n " failed");
                         return NGX_CHAIN_ERROR;
                     }

                 } else {
                     c->tcp_nopush = NGX_TCP_NOPUSH_SET;

                     ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
                                    "tcp_nopush");
                 }
             }

             /*
              * sendfile() does unneeded work if sf_hdtr's count is 0,
              * but corresponding pointer is not NULL
              */

             hdtr.headers = header.count ? header.iovs : NULL;
             hdtr.hdr_cnt = header.count;
             hdtr.trailers = trailer.count ? trailer.iovs : NULL;
             hdtr.trl_cnt = trailer.count;

             /*
              * the "nbytes bug" of the old sendfile() syscall:
              * http://bugs.freebsd.org/33771
              */

             if (!ngx_freebsd_sendfile_nbytes_bug) {
                 header.size = 0;
             }

             sent = 0;

 #if (NGX_HAVE_SENDFILE_NODISKIO)

             flags = (c->busy_count <= 2) ? SF_NODISKIO : 0;

             if (file->file->directio) {
                 flags |= SF_NOCACHE;
             }

 #endif

             rc = sendfile(file->file->fd, c->fd, file->file_pos,
                           file_size + header.size, &hdtr, &sent, flags);

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

                 switch (err) {
                 case NGX_EAGAIN:
                     eagain = 1;
                     break;

                 case NGX_EINTR:
                     eintr = 1;
                     break;

 #if (NGX_HAVE_SENDFILE_NODISKIO)
                 case NGX_EBUSY:
                     ebusy = 1;
                     break;
 #endif

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

                 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err,
                                "sendfile() sent only %O bytes", sent);

             /*
              * sendfile() in FreeBSD 3.x-4.x may return value >= 0
              * on success, although only 0 is documented
              */

             } else if (rc >= 0 && sent == 0) {

                 /*
                  * if rc is OK and sent equal to zero, then someone
                  * has truncated the file, so the offset became beyond
                  * the end of the file
                  */

                 ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "sendfile() reported that \"%s\" was truncated at %O",
                          file->file->name.data, file->file_pos);

                 return NGX_CHAIN_ERROR;
             }

             ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
                            "sendfile: %d, @%O %O:%uz",
                            rc, file->file_pos, sent, file_size + header.size);

         } else {
             n = ngx_writev(c, &header);

             if (n == NGX_ERROR) {
                 return NGX_CHAIN_ERROR;
             }

             sent = (n == NGX_AGAIN) ? 0 : n;
         }

         c->sent += sent;

         in = ngx_chain_update_sent(in, sent);

 #if (NGX_HAVE_SENDFILE_NODISKIO)

         if (ebusy) {
             if (sent == 0) {
                 c->busy_count++;

                 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                                "sendfile() busy, count:%d", c->busy_count);

             } else {
                 c->busy_count = 0;
             }

             if (wev->posted) {
                 ngx_delete_posted_event(wev);
             }

             ngx_post_event(wev, &ngx_posted_next_events);

             wev->ready = 0;
             return in;
         }

         c->busy_count = 0;

 #endif

         if (eagain) {

             /*
              * sendfile() may return EAGAIN, even if it has sent a whole file
              * part, it indicates that the successive sendfile() call would
              * return EAGAIN right away and would not send anything.
              * We use it as a hint.
              */

             wev->ready = 0;
             return in;
         }

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

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

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

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


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


	/*
	* Although FreeBSD sendfile() allows to pass a header and a trailer,
	* it cannot send a header with a part of the file in one packet until
	* FreeBSD 5.3. Besides, over the fast ethernet connection sendfile()
	* may send the partially filled packets, i.e. the 8 file pages may be sent
	* as the 11 full 1460-bytes packets, then one incomplete 324-bytes packet,
	* and then again the 11 full 1460-bytes packets.
	*
	* Therefore we use the TCP_NOPUSH option (similar to Linux's TCP_CORK)
	* to postpone the sending - it not only sends a header and the first part of
	* the file in one packet, but also sends the file pages in the full packets.
	*
	* But until FreeBSD 4.5 turning TCP_NOPUSH off does not flush a pending
	* data that less than MSS, so that data may be sent with 5 second delay.
	* So we do not use TCP_NOPUSH on FreeBSD prior to 4.5, although it can be used
	* for non-keepalive HTTP connections.
	*/


	ngx_chain_t *
	ngx_freebsd_sendfile_chain(ngx_connection_t c, ngx_chain_t in, off_t limit)
	{
	int rc, flags;
	off_t send, prev_send, sent;
	size_t file_size;
	ssize_t n;
	ngx_err_t err;
	ngx_buf_t *file;
	ngx_uint_t eintr, eagain;
	#if (NGX_HAVE_SENDFILE_NODISKIO)
	ngx_uint_t ebusy;
	#endif
	ngx_event_t *wev;
	ngx_chain_t *cl;
	ngx_iovec_t header, trailer;
	struct sf_hdtr hdtr;
	struct iovec headers[NGX_IOVS_PREALLOCATE];
	struct iovec trailers[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;
	eagain = 0;
	flags = 0;

	header.iovs = headers;
	header.nalloc = NGX_IOVS_PREALLOCATE;

	trailer.iovs = trailers;
	trailer.nalloc = NGX_IOVS_PREALLOCATE;

	for ( ;; ) {
	eintr = 0;
	#if (NGX_HAVE_SENDFILE_NODISKIO)
	ebusy = 0;
	#endif
	prev_send = send;

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

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

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

	send += header.size;

	if (cl && cl->buf->in_file && send < limit) {
	file = cl->buf;

	/* coalesce the neighbouring file bufs */

	file_size = (size_t) ngx_chain_coalesce_file(&cl, limit - send);

	send += file_size;

	if (send < limit) {

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

	cl = ngx_output_chain_to_iovec(&trailer, cl, limit - send,
	c->log);
	if (cl == NGX_CHAIN_ERROR) {
	return NGX_CHAIN_ERROR;
	}

	send += trailer.size;

	} else {
	trailer.count = 0;
	}

	if (ngx_freebsd_use_tcp_nopush
	&& c->tcp_nopush == NGX_TCP_NOPUSH_UNSET)
	{
	if (ngx_tcp_nopush(c->fd) == -1) {
	err = ngx_socket_errno;

	/*
	* there is a tiny chance to be interrupted, however,
	* we continue a processing without the TCP_NOPUSH
	*/

	if (err != NGX_EINTR) {
	wev->error = 1;
	(void) ngx_connection_error(c, err,
	ngx_tcp_nopush_n " failed");
	return NGX_CHAIN_ERROR;
	}

	} else {
	c->tcp_nopush = NGX_TCP_NOPUSH_SET;

	ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
	"tcp_nopush");
	}
	}

	/*
	* sendfile() does unneeded work if sf_hdtr's count is 0,
	* but corresponding pointer is not NULL
	*/

	hdtr.headers = header.count ? header.iovs : NULL;
	hdtr.hdr_cnt = header.count;
	hdtr.trailers = trailer.count ? trailer.iovs : NULL;
	hdtr.trl_cnt = trailer.count;

	/*
	* the "nbytes bug" of the old sendfile() syscall:
	* http://bugs.freebsd.org/33771
	*/

	if (!ngx_freebsd_sendfile_nbytes_bug) {
	header.size = 0;
	}

	sent = 0;

	#if (NGX_HAVE_SENDFILE_NODISKIO)

	flags = (c->busy_count <= 2) ? SF_NODISKIO : 0;

	if (file->file->directio) {
	flags \|= SF_NOCACHE;
	}

	#endif

	rc = sendfile(file->file->fd, c->fd, file->file_pos,
	file_size + header.size, &hdtr, &sent, flags);

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

	switch (err) {
	case NGX_EAGAIN:
	eagain = 1;
	break;

	case NGX_EINTR:
	eintr = 1;
	break;

	#if (NGX_HAVE_SENDFILE_NODISKIO)
	case NGX_EBUSY:
	ebusy = 1;
	break;
	#endif

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

	ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err,
	"sendfile() sent only %O bytes", sent);

	/*
	* sendfile() in FreeBSD 3.x-4.x may return value >= 0
	* on success, although only 0 is documented
	*/

	} else if (rc >= 0 && sent == 0) {

	/*
	* if rc is OK and sent equal to zero, then someone
	* has truncated the file, so the offset became beyond
	* the end of the file
	*/

	ngx_log_error(NGX_LOG_ALERT, c->log, 0,
	"sendfile() reported that \"%s\" was truncated at %O",
	file->file->name.data, file->file_pos);

	return NGX_CHAIN_ERROR;
	}

	ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
	"sendfile: %d, @%O %O:%uz",
	rc, file->file_pos, sent, file_size + header.size);

	} else {
	n = ngx_writev(c, &header);

	if (n == NGX_ERROR) {
	return NGX_CHAIN_ERROR;
	}

	sent = (n == NGX_AGAIN) ? 0 : n;
	}

	c->sent += sent;

	in = ngx_chain_update_sent(in, sent);

	#if (NGX_HAVE_SENDFILE_NODISKIO)

	if (ebusy) {
	if (sent == 0) {
	c->busy_count++;

	ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
	"sendfile() busy, count:%d", c->busy_count);

	} else {
	c->busy_count = 0;
	}

	if (wev->posted) {
	ngx_delete_posted_event(wev);
	}

	ngx_post_event(wev, &ngx_posted_next_events);

	wev->ready = 0;
	return in;
	}

	c->busy_count = 0;

	#endif

	if (eagain) {

	/*
	* sendfile() may return EAGAIN, even if it has sent a whole file
	* part, it indicates that the successive sendfile() call would
	* return EAGAIN right away and would not send anything.
	* We use it as a hint.
	*/

	wev->ready = 0;
	return in;
	}

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

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

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