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Diffstat (limited to 'modules/http/chunk_filter.c')
| -rw-r--r-- | modules/http/chunk_filter.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/modules/http/chunk_filter.c b/modules/http/chunk_filter.c new file mode 100644 index 0000000..cb1501a --- /dev/null +++ b/modules/http/chunk_filter.c @@ -0,0 +1,197 @@ +/* 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; +} |