I am writing filter for Apache/2.2.11. In the filter I want to read the POST data of the request. To achieve this I written a code to read the data from brigade/bucket. The code is working fine if "ap_get_brigade" api is called in "AP_MODE_READBYTES" mode. I am able to read complete post data of the request. But it is failing in case "ap_get_brigade" api is called in "AP_MODE_SPECULATIVE" mode. Actually after reading post data in the filter, post data should not be cleared and it should be accessible to downstream application so I want to use AP_MODE_SPECULATIVE. I found that in the failure case "ap_get_brigade" is returning the same chunk of data. Here pasting the code snippet: int printPost(request_rec* rqRec) { apr_status_t retStatus; apr_bucket_brigade *bb; apr_bucket *bucket; ap_input_mode_t read_mode; int nread = 0; bool seen_eos=false; const char *data; apr_size_t len; int nBytes = 0; const char *contentLengthStr = apr_table_get(rqRec->headers_in, "Content-Length"); nBytes = atoi(contentLengthStr); fprintf(stderr,"\n URI:%s, content-length:%d", rqRec->uri,nBytes); char * freep = (char *)malloc(nBytes + 1); char * qstr = freep; memset(qstr, 0, nBytes + 1); // Create a bucket brigade to fill data from the input filter bb = apr_brigade_create(rqRec->pool, rqRec->connection->bucket_alloc); read_mode = AP_MODE_SPECULATIVE; //AP_MODE_READBYTES do { // Get the bucket brigade filled from the input filter retStatus = ap_get_brigade(rqRec->input_filters, bb, read_mode, APR_BLOCK_READ, nBytes); if ( retStatus != APR_SUCCESS ){ fprintf(stderr,"\n Failed ap_get_brigade"); goto endhere; } for (bucket = APR_BRIGADE_FIRST(bb); bucket != APR_BRIGADE_SENTINEL(bb); bucket = APR_BUCKET_NEXT(bucket)) { data = NULL; len = 0; if (APR_BUCKET_IS_EOS(bucket)) { seen_eos = true; break; } if (APR_BUCKET_IS_FLUSH(bucket)) { continue; } // bucket_read function sets the data pointer to its internal buffer and returns the len field retStatus = apr_bucket_read(bucket, &data, &len, APR_BLOCK_READ); if ( retStatus != APR_SUCCESS) { fprintf(stderr,"\n Failed apr_bucket_read"); goto endhere; //return 0; } fprintf(stderr,"\n bucket->length :%d",bucket->length); fprintf(stderr,"\n nread:%d len :%d op:%d, retStatus:%d", nread, (int )len, (nread + (int )len >nBytes),(int)retStatus); char * tp = (char *)malloc((int )len + 1); memset(tp, 0, len + 1); memcpy(tp, data, len); fprintf(stderr,"\n DATA from the current bucket :%s",tp); free(tp); if (nread + (int )len > nBytes) { fprintf(stderr,"\n Too much POST data: %s", rqRec->uri); seen_eos = true; break; } memcpy(qstr, data, len); qstr += len; nread += len; if (nread == nBytes) { seen_eos = true; break; } }/* End of For loop*/ apr_brigade_cleanup(bb); } while (!seen_eos); endhere: fprintf(stderr,"\n FINAL POST DATA :%s",freep); free(freep); return nread; } If I post some data, output looks like: URI:/test.cgi, content-length:5537 bucket->length :764 nread:0 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:764 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:1528 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:2292 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:3056 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:3820 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:4584 len :764 op:0, retStatus:0 DATA from the current bucket :post_data=start1111............................ bucket->length :764 nread:5348 len :764 op:1, retStatus:0 DATA from the current bucket :post_data=start1111............................ Too much POST data: /test.cgi FINAL POST DATA :post_data=start1111....111post_data=start11111....1111post_data=start111111. ...111post_data=start11111....1post_data=start111....111post_data=start11111. ...1111post_data=start111111...... In the above code, If I change the read_mode to AP_MODE_READBYTES and post the same request, output looks like: URI:/test.cgi, content-length:5537 bucket->length :2024 nread:0 len :2024 op:0, retStatus:0 DATA from the current bucket :post_data=start11111............................ bucket->length :1260 nread:2024 len :1260 op:0, retStatus:0 DATA from the current bucket :111111111111111............................. bucket->length :2253 nread:3284 len :2253 op:0, retStatus:0 DATA from the current bucket :111111111.........................1111111End FINAL POST DATA :post_data=start11111111111111.........................1111111111111111End Using same code and setting read_mode to AP_MODE_SPECULATIVE, on windows platform issue is not seen. Issue is seen on Linux & Linux64 of RHEL4 version. Post data size need to be more than 5000 bytes.
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