buckets/apr_buckets_pipe.c

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "apr_buckets.h"
  18
  19 static apr_status_t pipe_bucket_read(apr_bucket *a, const char **str,
  20                                      apr_size_t *len, apr_read_type_e block)
  21 {
  22     apr_file_t *p = a->data;
  23     char *buf;
  24     apr_status_t rv;
  25     apr_interval_time_t timeout;
  26
  27     if (block == APR_NONBLOCK_READ) {
  28         apr_file_pipe_timeout_get(p, &timeout);
  29         apr_file_pipe_timeout_set(p, 0);
  30     }
  31
  32     *str = NULL;
  33     *len = APR_BUCKET_BUFF_SIZE;
  34     buf = apr_bucket_alloc(*len, a->list); /* XXX: check for failure? */
  35
  36     rv = apr_file_read(p, buf, len);
  37
  38     if (block == APR_NONBLOCK_READ) {
  39         apr_file_pipe_timeout_set(p, timeout);
  40     }
  41
  42     if (rv != APR_SUCCESS && rv != APR_EOF) {
  43         apr_bucket_free(buf);
  44         return rv;
  45     }
  46     /*
  47      * If there's more to read we have to keep the rest of the pipe
  48      * for later.  Otherwise, we'll close the pipe.
  49      * XXX: Note that more complicated bucket types that
  50      * refer to data not in memory and must therefore have a read()
  51      * function similar to this one should be wary of copying this
  52      * code because if they have a destroy function they probably
  53      * want to migrate the bucket's subordinate structure from the
  54      * old bucket to a raw new one and adjust it as appropriate,
  55      * rather than destroying the old one and creating a completely
  56      * new bucket.
  57      */
  58     if (*len > 0) {
  59         apr_bucket_heap *h;
  60         /* Change the current bucket to refer to what we read */
  61         a = apr_bucket_heap_make(a, buf, *len, apr_bucket_free);
  62         h = a->data;
  63         h->alloc_len = APR_BUCKET_BUFF_SIZE; /* note the real buffer size */
  64         *str = buf;
  65         APR_BUCKET_INSERT_AFTER(a, apr_bucket_pipe_create(p, a->list));
  66     }
  67     else {
  68         apr_bucket_free(buf);
  69         a = apr_bucket_immortal_make(a, "", 0);
  70         *str = a->data;
  71         if (rv == APR_EOF) {
  72             apr_file_close(p);
  73         }
  74     }
  75     return APR_SUCCESS;
  76 }
  77
  78 APU_DECLARE(apr_bucket *) apr_bucket_pipe_make(apr_bucket *b, apr_file_t *p)
  79 {
  80     /*
  81      * A pipe is closed when the end is reached in pipe_bucket_read().  If
  82      * the pipe isn't read to the end (e.g., error path), the pipe will be
  83      * closed when its pool goes away.
  84      *
  85      * Note that typically the pipe is allocated from the request pool
  86      * so it will disappear when the request is finished. However the
  87      * core filter may decide to set aside the tail end of a CGI
  88      * response if the connection is pipelined. This turns out not to
  89      * be a problem because the core will have read to the end of the
  90      * stream so the bucket(s) that it sets aside will be the heap
  91      * buckets created by pipe_bucket_read() above.
  92      */
  93     b->type        = &apr_bucket_type_pipe;
  94     b->length      = (apr_size_t)(-1);
  95     b->start       = -1;
  96     b->data        = p;
  97
  98     return b;
  99 }
 100
 101 APU_DECLARE(apr_bucket *) apr_bucket_pipe_create(apr_file_t *p,
 102                                                  apr_bucket_alloc_t *list)
 103 {
 104     apr_bucket *b = apr_bucket_alloc(sizeof(*b), list);
 105
 106     APR_BUCKET_INIT(b);
 107     b->free = apr_bucket_free;
 108     b->list = list;
 109     return apr_bucket_pipe_make(b, p);
 110 }
 111
 112 APU_DECLARE_DATA const apr_bucket_type_t apr_bucket_type_pipe = {
 113     "PIPE", 5, APR_BUCKET_DATA,
 114     apr_bucket_destroy_noop,
 115     pipe_bucket_read,
 116     apr_bucket_setaside_notimpl,
 117     apr_bucket_split_notimpl,
 118     apr_bucket_copy_notimpl
 119 };