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/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* chunk_filter.c --- HTTP/1.1 chunked transfer encoding filter.
*/
#include "apr_strings.h"
#include "apr_thread_proc.h" /* for RLIMIT stuff */
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include "httpd.h"
#include "http_config.h"
#include "http_connection.h"
#include "http_core.h"
#include "http_protocol.h" /* For index_of_response(). Grump. */
#include "http_request.h"
#include "util_filter.h"
#include "util_ebcdic.h"
#include "ap_mpm.h"
#include "scoreboard.h"
#include "mod_core.h"
/*
* A pointer to this is used to memorize in the filter context that a bad
* gateway error bucket had been seen. It is used as an invented unique pointer.
*/
static char bad_gateway_seen;
apr_status_t ap_http_chunk_filter(ap_filter_t *f, apr_bucket_brigade *b)
{
#define ASCII_CRLF "\015\012"
#define ASCII_ZERO "\060"
conn_rec *c = f->r->connection;
apr_bucket_brigade *more, *tmp;
apr_bucket *e;
apr_status_t rv;
for (more = tmp = NULL; b; b = more, more = NULL) {
apr_off_t bytes = 0;
apr_bucket *eos = NULL;
apr_bucket *flush = NULL;
/* XXX: chunk_hdr must remain at this scope since it is used in a
* transient bucket.
*/
char chunk_hdr[20]; /* enough space for the snprintf below */
for (e = APR_BRIGADE_FIRST(b);
e != APR_BRIGADE_SENTINEL(b);
e = APR_BUCKET_NEXT(e))
{
if (APR_BUCKET_IS_EOS(e)) {
/* there shouldn't be anything after the eos */
ap_remove_output_filter(f);
eos = e;
break;
}
if (AP_BUCKET_IS_ERROR(e)
&& (((ap_bucket_error *)(e->data))->status
== HTTP_BAD_GATEWAY)) {
/*
* We had a broken backend. Memorize this in the filter
* context.
*/
f->ctx = &bad_gateway_seen;
continue;
}
if (APR_BUCKET_IS_FLUSH(e)) {
flush = e;
if (e != APR_BRIGADE_LAST(b)) {
more = apr_brigade_split_ex(b, APR_BUCKET_NEXT(e), tmp);
}
break;
}
else if (e->length == (apr_size_t)-1) {
/* unknown amount of data (e.g. a pipe) */
const char *data;
apr_size_t len;
rv = apr_bucket_read(e, &data, &len, APR_BLOCK_READ);
if (rv != APR_SUCCESS) {
return rv;
}
if (len > 0) {
/*
* There may be a new next bucket representing the
* rest of the data stream on which a read() may
* block so we pass down what we have so far.
*/
bytes += len;
more = apr_brigade_split_ex(b, APR_BUCKET_NEXT(e), tmp);
break;
}
else {
/* If there was nothing in this bucket then we can
* safely move on to the next one without pausing
* to pass down what we have counted up so far.
*/
continue;
}
}
else {
bytes += e->length;
}
}
/*
* XXX: if there aren't very many bytes at this point it may
* be a good idea to set them aside and return for more,
* unless we haven't finished counting this brigade yet.
*/
/* if there are content bytes, then wrap them in a chunk */
if (bytes > 0) {
apr_size_t hdr_len;
/*
* Insert the chunk header, specifying the number of bytes in
* the chunk.
*/
hdr_len = apr_snprintf(chunk_hdr, sizeof(chunk_hdr),
"%" APR_UINT64_T_HEX_FMT CRLF, (apr_uint64_t)bytes);
ap_xlate_proto_to_ascii(chunk_hdr, hdr_len);
e = apr_bucket_transient_create(chunk_hdr, hdr_len,
c->bucket_alloc);
APR_BRIGADE_INSERT_HEAD(b, e);
/*
* Insert the end-of-chunk CRLF before an EOS or
* FLUSH bucket, or appended to the brigade
*/
e = apr_bucket_immortal_create(ASCII_CRLF, 2, c->bucket_alloc);
if (eos != NULL) {
APR_BUCKET_INSERT_BEFORE(eos, e);
}
else if (flush != NULL) {
APR_BUCKET_INSERT_BEFORE(flush, e);
}
else {
APR_BRIGADE_INSERT_TAIL(b, e);
}
}
/* RFC 2616, Section 3.6.1
*
* If there is an EOS bucket, then prefix it with:
* 1) the last-chunk marker ("0" CRLF)
* 2) the trailer
* 3) the end-of-chunked body CRLF
*
* We only do this if we have not seen an error bucket with
* status HTTP_BAD_GATEWAY. We have memorized an
* error bucket that we had seen in the filter context.
* The error bucket with status HTTP_BAD_GATEWAY indicates that the
* connection to the backend (mod_proxy) broke in the middle of the
* response. In order to signal the client that something went wrong
* we do not create the last-chunk marker and set c->keepalive to
* AP_CONN_CLOSE in the core output filter.
*
* XXX: it would be nice to combine this with the end-of-chunk
* marker above, but this is a bit more straight-forward for
* now.
*/
if (eos && !f->ctx) {
/* XXX: (2) trailers ... does not yet exist */
e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
/* <trailers> */
ASCII_CRLF, 5, c->bucket_alloc);
APR_BUCKET_INSERT_BEFORE(eos, e);
}
/* pass the brigade to the next filter. */
rv = ap_pass_brigade(f->next, b);
apr_brigade_cleanup(b);
if (rv != APR_SUCCESS || eos != NULL) {
return rv;
}
tmp = b;
}
return APR_SUCCESS;
}
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