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Linux Cross Reference
Nginx/core/ngx_output_chain.c

Version: ~ [ nginx-0.8.20 ] ~ [ nginx-0.7.62 ] ~ [ nginx-0.6.39 ] ~

  1 
  2 /*
  3  * Copyright (C) Igor Sysoev
  4  */
  5 
  6 
  7 #include <ngx_config.h>
  8 #include <ngx_core.h>
  9 #include <ngx_event.h>
 10 
 11 
 12 #if 0
 13 #define NGX_SENDFILE_LIMIT  4096
 14 #endif
 15 
 16 /*
 17  * When DIRECTIO is enabled FreeBSD, Solaris, and MacOSX read directly
 18  * to an application memory from a device if parameters are aligned
 19  * to device sector boundary(512 bytes).  They fallback to usual read
 20  * operation if the parameters are not aligned.
 21  * Linux allows DIRECTIO only if the parameters are aligned to a filesystem
 22  * sector boundary, otherwise it returns EINVAL.  The sector size is
 23  * usually 512 bytes, however, on XFS it may be 4096 bytes.
 24  */
 25 #define NGX_DIRECTIO_BLOCK  4096
 26 
 27 
 28 #define NGX_NONE            1
 29 
 30 
 31 static ngx_inline ngx_int_t
 32     ngx_output_chain_as_is(ngx_output_chain_ctx_t *ctx, ngx_buf_t *buf);
 33 static ngx_int_t ngx_output_chain_add_copy(ngx_pool_t *pool,
 34     ngx_chain_t **chain, ngx_chain_t *in);
 35 static ngx_int_t ngx_output_chain_align_file_buf(ngx_output_chain_ctx_t *ctx,
 36     off_t bsize);
 37 static ngx_int_t ngx_output_chain_get_buf(ngx_output_chain_ctx_t *ctx,
 38     off_t bsize);
 39 static ngx_int_t ngx_output_chain_copy_buf(ngx_output_chain_ctx_t *ctx);
 40 
 41 
 42 ngx_int_t
 43 ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in)
 44 {
 45     off_t         bsize;
 46     ngx_int_t     rc, last;
 47     ngx_chain_t  *cl, *out, **last_out;
 48 
 49     if (ctx->in == NULL && ctx->busy == NULL) {
 50 
 51         /*
 52          * the short path for the case when the ctx->in and ctx->busy chains
 53          * are empty, the incoming chain is empty too or has the single buf
 54          * that does not require the copy
 55          */
 56 
 57         if (in == NULL) {
 58             return ctx->output_filter(ctx->filter_ctx, in);
 59         }
 60 
 61         if (in->next == NULL
 62 #if (NGX_SENDFILE_LIMIT)
 63             && !(in->buf->in_file && in->buf->file_last > NGX_SENDFILE_LIMIT)
 64 #endif
 65             && ngx_output_chain_as_is(ctx, in->buf))
 66         {
 67             return ctx->output_filter(ctx->filter_ctx, in);
 68         }
 69     }
 70 
 71     /* add the incoming buf to the chain ctx->in */
 72 
 73     if (in) {
 74         if (ngx_output_chain_add_copy(ctx->pool, &ctx->in, in) == NGX_ERROR) {
 75             return NGX_ERROR;
 76         }
 77     }
 78 
 79     out = NULL;
 80     last_out = &out;
 81     last = NGX_NONE;
 82 
 83     for ( ;; ) {
 84 
 85         while (ctx->in) {
 86 
 87             /*
 88              * cycle while there are the ctx->in bufs
 89              * and there are the free output bufs to copy in
 90              */
 91 
 92             bsize = ngx_buf_size(ctx->in->buf);
 93 
 94             if (bsize == 0 && !ngx_buf_special(ctx->in->buf)) {
 95 
 96                 ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
 97                               "zero size buf in output "
 98                               "t:%d r:%d f:%d %p %p-%p %p %O-%O",
 99                               ctx->in->buf->temporary,
100                               ctx->in->buf->recycled,
101                               ctx->in->buf->in_file,
102                               ctx->in->buf->start,
103                               ctx->in->buf->pos,
104                               ctx->in->buf->last,
105                               ctx->in->buf->file,
106                               ctx->in->buf->file_pos,
107                               ctx->in->buf->file_last);
108 
109                 ngx_debug_point();
110 
111                 ctx->in = ctx->in->next;
112 
113                 continue;
114             }
115 
116             if (ngx_output_chain_as_is(ctx, ctx->in->buf)) {
117 
118                 /* move the chain link to the output chain */
119 
120                 cl = ctx->in;
121                 ctx->in = cl->next;
122 
123                 *last_out = cl;
124                 last_out = &cl->next;
125                 cl->next = NULL;
126 
127                 continue;
128             }
129 
130             if (ctx->buf == NULL) {
131 
132                 rc = ngx_output_chain_align_file_buf(ctx, bsize);
133 
134                 if (rc == NGX_ERROR) {
135                     return NGX_ERROR;
136                 }
137 
138                 if (rc != NGX_OK) {
139 
140                     if (ctx->free) {
141 
142                         /* get the free buf */
143 
144                         cl = ctx->free;
145                         ctx->buf = cl->buf;
146                         ctx->free = cl->next;
147 
148                         ngx_free_chain(ctx->pool, cl);
149 
150                     } else if (out || ctx->allocated == ctx->bufs.num) {
151 
152                         break;
153 
154                     } else if (ngx_output_chain_get_buf(ctx, bsize) != NGX_OK) {
155                         return NGX_ERROR;
156                     }
157                 }
158             }
159 
160             rc = ngx_output_chain_copy_buf(ctx);
161 
162             if (rc == NGX_ERROR) {
163                 return rc;
164             }
165 
166             if (rc == NGX_AGAIN) {
167                 if (out) {
168                     break;
169                 }
170 
171                 return rc;
172             }
173 
174             /* delete the completed buf from the ctx->in chain */
175 
176             if (ngx_buf_size(ctx->in->buf) == 0) {
177                 ctx->in = ctx->in->next;
178             }
179 
180             cl = ngx_alloc_chain_link(ctx->pool);
181             if (cl == NULL) {
182                 return NGX_ERROR;
183             }
184 
185             cl->buf = ctx->buf;
186             cl->next = NULL;
187             *last_out = cl;
188             last_out = &cl->next;
189             ctx->buf = NULL;
190         }
191 
192         if (out == NULL && last != NGX_NONE) {
193 
194             if (ctx->in) {
195                 return NGX_AGAIN;
196             }
197 
198             return last;
199         }
200 
201         last = ctx->output_filter(ctx->filter_ctx, out);
202 
203         if (last == NGX_ERROR || last == NGX_DONE) {
204             return last;
205         }
206 
207         ngx_chain_update_chains(&ctx->free, &ctx->busy, &out, ctx->tag);
208         last_out = &out;
209     }
210 }
211 
212 
213 static ngx_inline ngx_int_t
214 ngx_output_chain_as_is(ngx_output_chain_ctx_t *ctx, ngx_buf_t *buf)
215 {
216     ngx_uint_t  sendfile;
217 
218     if (ngx_buf_special(buf)) {
219         return 1;
220     }
221 
222     if (buf->in_file && buf->file->directio) {
223         return 0;
224     }
225 
226     sendfile = ctx->sendfile;
227 
228 #if (NGX_SENDFILE_LIMIT)
229 
230     if (buf->in_file && buf->file_pos >= NGX_SENDFILE_LIMIT) {
231         sendfile = 0;
232     }
233 
234 #endif
235 
236     if (!sendfile) {
237 
238         if (!ngx_buf_in_memory(buf)) {
239             return 0;
240         }
241 
242         buf->in_file = 0;
243     }
244 
245     if (ctx->need_in_memory && !ngx_buf_in_memory(buf)) {
246         return 0;
247     }
248 
249     if (ctx->need_in_temp && (buf->memory || buf->mmap)) {
250         return 0;
251     }
252 
253     return 1;
254 }
255 
256 
257 static ngx_int_t
258 ngx_output_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain,
259     ngx_chain_t *in)
260 {
261     ngx_chain_t  *cl, **ll;
262 #if (NGX_SENDFILE_LIMIT)
263     ngx_buf_t    *b, *buf;
264 #endif
265 
266     ll = chain;
267 
268     for (cl = *chain; cl; cl = cl->next) {
269         ll = &cl->next;
270     }
271 
272     while (in) {
273 
274         cl = ngx_alloc_chain_link(pool);
275         if (cl == NULL) {
276             return NGX_ERROR;
277         }
278 
279 #if (NGX_SENDFILE_LIMIT)
280 
281         buf = in->buf;
282 
283         if (buf->in_file
284             && buf->file_pos < NGX_SENDFILE_LIMIT
285             && buf->file_last > NGX_SENDFILE_LIMIT)
286         {
287             /* split a file buf on two bufs by the sendfile limit */
288 
289             b = ngx_calloc_buf(pool);
290             if (b == NULL) {
291                 return NGX_ERROR;
292             }
293 
294             ngx_memcpy(b, buf, sizeof(ngx_buf_t));
295 
296             if (ngx_buf_in_memory(buf)) {
297                 buf->pos += (ssize_t) (NGX_SENDFILE_LIMIT - buf->file_pos);
298                 b->last = buf->pos;
299             }
300 
301             buf->file_pos = NGX_SENDFILE_LIMIT;
302             b->file_last = NGX_SENDFILE_LIMIT;
303 
304             cl->buf = b;
305 
306         } else {
307             cl->buf = buf;
308             in = in->next;
309         }
310 
311 #else
312         cl->buf = in->buf;
313         in = in->next;
314 
315 #endif
316 
317         *ll = cl;
318         ll = &cl->next;
319     }
320 
321     *ll = NULL;
322 
323     return NGX_OK;
324 }
325 
326 
327 static ngx_int_t
328 ngx_output_chain_align_file_buf(ngx_output_chain_ctx_t *ctx, off_t bsize)
329 {
330     size_t      size;
331     ngx_buf_t  *in;
332 
333     in = ctx->in->buf;
334 
335     if (in->file == NULL || !in->file->directio) {
336         return NGX_DECLINED;
337     }
338 
339     ctx->directio = 1;
340 
341     size = (size_t) (in->file_pos - (in->file_pos & ~(NGX_DIRECTIO_BLOCK - 1)));
342 
343     if (size == 0) {
344 
345         if (bsize >= (off_t) ctx->bufs.size) {
346             return NGX_DECLINED;
347         }
348 
349         size = (size_t) bsize;
350 
351     } else {
352         size = NGX_DIRECTIO_BLOCK - size;
353 
354         if ((off_t) size > bsize) {
355             size = (size_t) bsize;
356         }
357     }
358 
359     ctx->buf = ngx_create_temp_buf(ctx->pool, size);
360     if (ctx->buf == NULL) {
361         return NGX_ERROR;
362     }
363 
364     /*
365      * we do not set ctx->buf->tag, because we do not want
366      * to reuse the buf via ctx->free list
367      */
368 
369 #if (NGX_HAVE_ALIGNED_DIRECTIO)
370     ctx->unaligned = 1;
371 #endif
372 
373     return NGX_OK;
374 }
375 
376 
377 static ngx_int_t
378 ngx_output_chain_get_buf(ngx_output_chain_ctx_t *ctx, off_t bsize)
379 {
380     size_t       size;
381     ngx_buf_t   *b, *in;
382     ngx_uint_t   recycled;
383 
384     in = ctx->in->buf;
385     size = ctx->bufs.size;
386     recycled = 1;
387 
388     if (in->last_in_chain) {
389 
390         if (bsize < (off_t) size) {
391 
392             /*
393              * allocate a small temp buf for a small last buf
394              * or its small last part
395              */
396 
397             size = (size_t) bsize;
398             recycled = 0;
399 
400         } else if (!ctx->directio
401                    && ctx->bufs.num == 1
402                    && (bsize < (off_t) (size + size / 4)))
403         {
404             /*
405              * allocate a temp buf that equals to a last buf,
406              * if there is no directio, the last buf size is lesser
407              * than 1.25 of bufs.size and the temp buf is single
408              */
409 
410             size = (size_t) bsize;
411             recycled = 0;
412         }
413     }
414 
415     b = ngx_calloc_buf(ctx->pool);
416     if (b == NULL) {
417         return NGX_ERROR;
418     }
419 
420     if (ctx->directio) {
421 
422         /*
423          * allocate block aligned to a disk sector size to enable
424          * userland buffer direct usage conjunctly with directio
425          */
426 
427         b->start = ngx_pmemalign(ctx->pool, size, NGX_DIRECTIO_BLOCK);
428         if (b->start == NULL) {
429             return NGX_ERROR;
430         }
431 
432     } else {
433         b->start = ngx_palloc(ctx->pool, size);
434         if (b->start == NULL) {
435             return NGX_ERROR;
436         }
437     }
438 
439     b->pos = b->start;
440     b->last = b->start;
441     b->end = b->last + size;
442     b->temporary = 1;
443     b->tag = ctx->tag;
444     b->recycled = recycled;
445 
446     ctx->buf = b;
447     ctx->allocated++;
448 
449     return NGX_OK;
450 }
451 
452 
453 static ngx_int_t
454 ngx_output_chain_copy_buf(ngx_output_chain_ctx_t *ctx)
455 {
456     off_t        size;
457     ssize_t      n;
458     ngx_buf_t   *src, *dst;
459     ngx_uint_t   sendfile;
460 
461     src = ctx->in->buf;
462     dst = ctx->buf;
463 
464     size = ngx_buf_size(src);
465 
466     if (size > dst->end - dst->pos) {
467         size = dst->end - dst->pos;
468     }
469 
470     sendfile = ctx->sendfile & !ctx->directio;
471 
472 #if (NGX_SENDFILE_LIMIT)
473 
474     if (src->in_file && src->file_pos >= NGX_SENDFILE_LIMIT) {
475         sendfile = 0;
476     }
477 
478 #endif
479 
480     if (ngx_buf_in_memory(src)) {
481         ngx_memcpy(dst->pos, src->pos, (size_t) size);
482         src->pos += (size_t) size;
483         dst->last += (size_t) size;
484 
485         if (src->in_file) {
486 
487             if (sendfile) {
488                 dst->in_file = 1;
489                 dst->file = src->file;
490                 dst->file_pos = src->file_pos;
491                 dst->file_last = src->file_pos + size;
492 
493             } else {
494                 dst->in_file = 0;
495             }
496 
497             src->file_pos += size;
498 
499         } else {
500             dst->in_file = 0;
501         }
502 
503         if (src->pos == src->last) {
504             dst->flush = src->flush;
505             dst->last_buf = src->last_buf;
506             dst->last_in_chain = src->last_in_chain;
507         }
508 
509     } else {
510 
511 #if (NGX_HAVE_ALIGNED_DIRECTIO)
512 
513         if (ctx->unaligned) {
514             if (ngx_directio_off(src->file->fd) == -1) {
515                 ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, ngx_errno,
516                               ngx_directio_off_n " \"%s\" failed",
517                               src->file->name.data);
518             }
519         }
520 
521 #endif
522 
523         n = ngx_read_file(src->file, dst->pos, (size_t) size, src->file_pos);
524 
525 #if (NGX_HAVE_ALIGNED_DIRECTIO)
526 
527         if (ctx->unaligned) {
528             ngx_err_t  err;
529 
530             err = ngx_errno;
531 
532             if (ngx_directio_on(src->file->fd) == -1) {
533                 ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, ngx_errno,
534                               ngx_directio_on_n " \"%s\" failed",
535                               src->file->name.data);
536             }
537 
538             ngx_set_errno(err);
539 
540             ctx->unaligned = 0;
541         }
542 
543 #endif
544 
545         if (n == NGX_ERROR) {
546             return (ngx_int_t) n;
547         }
548 
549 #if (NGX_FILE_AIO_READ)
550         if (n == NGX_AGAIN) {
551             return (ngx_int_t) n;
552         }
553 #endif
554 
555         if (n != size) {
556             ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
557                           ngx_read_file_n " read only %z of %O from \"%s\"",
558                           n, size, src->file->name.data);
559             if (n == 0) {
560                 return NGX_ERROR;
561             }
562         }
563 
564         dst->last += n;
565 
566         if (sendfile) {
567             dst->in_file = 1;
568             dst->file = src->file;
569             dst->file_pos = src->file_pos;
570             dst->file_last = src->file_pos + n;
571 
572         } else {
573             dst->in_file = 0;
574         }
575 
576         src->file_pos += n;
577 
578         if (src->file_pos == src->file_last) {
579             dst->flush = src->flush;
580             dst->last_buf = src->last_buf;
581             dst->last_in_chain = src->last_in_chain;
582         }
583     }
584 
585     return NGX_OK;
586 }
587 
588 
589 ngx_int_t
590 ngx_chain_writer(void *data, ngx_chain_t *in)
591 {
592     ngx_chain_writer_ctx_t *ctx = data;
593 
594     off_t              size;
595     ngx_chain_t       *cl;
596     ngx_connection_t  *c;
597 
598     c = ctx->connection;
599 
600     for (size = 0; in; in = in->next) {
601 
602 #if 1
603         if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) {
604             ngx_debug_point();
605         }
606 #endif
607 
608         size += ngx_buf_size(in->buf);
609 
610         ngx_log_debug2(NGX_LOG_DEBUG_CORE, c->log, 0,
611                        "chain writer buf fl:%d s:%uO",
612                        in->buf->flush, ngx_buf_size(in->buf));
613 
614         cl = ngx_alloc_chain_link(ctx->pool);
615         if (cl == NULL) {
616             return NGX_ERROR;
617         }
618 
619         cl->buf = in->buf;
620         cl->next = NULL;
621         *ctx->last = cl;
622         ctx->last = &cl->next;
623     }
624 
625     ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
626                    "chain writer in: %p", ctx->out);
627 
628     for (cl = ctx->out; cl; cl = cl->next) {
629 
630 #if 1
631         if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
632             ngx_debug_point();
633         }
634 
635 #endif
636 
637         size += ngx_buf_size(cl->buf);
638     }
639 
640     if (size == 0 && !c->buffered) {
641         return NGX_OK;
642     }
643 
644     ctx->out = c->send_chain(c, ctx->out, ctx->limit);
645 
646     ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
647                    "chain writer out: %p", ctx->out);
648 
649     if (ctx->out == NGX_CHAIN_ERROR) {
650         return NGX_ERROR;
651     }
652 
653     if (ctx->out == NULL) {
654         ctx->last = &ctx->out;
655 
656         if (!c->buffered) {
657             return NGX_OK;
658         }
659     }
660 
661     return NGX_AGAIN;
662 }
663 

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