Adding upstream version 2.4.57.upstream/2.4.57

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 653 insertions, 0 deletions

diff --git a/modules/md/md_curl.c b/modules/md/md_curl.c
new file mode 100644
index 0000000..217e857
--- /dev/null
+++ b/modules/md/md_curl.c
@@ -0,0 +1,653 @@
+/* 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.
+ */
+ 
+#include <assert.h>
+
+#include <curl/curl.h>
+
+#include <apr_lib.h>
+#include <apr_strings.h>
+#include <apr_buckets.h>
+
+#include "md_http.h"
+#include "md_log.h"
+#include "md_util.h"
+#include "md_curl.h"
+
+/**************************************************************************************************/
+/* md_http curl implementation */
+
+
+static apr_status_t curl_status(unsigned int curl_code)
+{
+    switch (curl_code) {
+        case CURLE_OK:                   return APR_SUCCESS;
+        case CURLE_UNSUPPORTED_PROTOCOL: return APR_ENOTIMPL; 
+        case CURLE_NOT_BUILT_IN:         return APR_ENOTIMPL; 
+        case CURLE_URL_MALFORMAT:        return APR_EINVAL;
+        case CURLE_COULDNT_RESOLVE_PROXY:return APR_ECONNREFUSED;
+        case CURLE_COULDNT_RESOLVE_HOST: return APR_ECONNREFUSED;
+        case CURLE_COULDNT_CONNECT:      return APR_ECONNREFUSED;
+        case CURLE_REMOTE_ACCESS_DENIED: return APR_EACCES;
+        case CURLE_OUT_OF_MEMORY:        return APR_ENOMEM;
+        case CURLE_OPERATION_TIMEDOUT:   return APR_TIMEUP;
+        case CURLE_SSL_CONNECT_ERROR:    return APR_ECONNABORTED;
+        case CURLE_AGAIN:                return APR_EAGAIN;
+        default:                         return APR_EGENERAL;
+    }
+}
+
+typedef struct {
+    CURL *curl;
+    CURLM *curlm;
+    struct curl_slist *req_hdrs;
+    md_http_response_t *response;
+    apr_status_t rv;
+    int status_fired;
+} md_curl_internals_t;
+
+static size_t req_data_cb(void *data, size_t len, size_t nmemb, void *baton)
+{
+    apr_bucket_brigade *body = baton;
+    size_t blen, read_len = 0, max_len = len * nmemb;
+    const char *bdata;
+    char *rdata = data;
+    apr_bucket *b;
+    apr_status_t rv;
+    
+    while (body && !APR_BRIGADE_EMPTY(body) && max_len > 0) {
+        b = APR_BRIGADE_FIRST(body);
+        if (APR_BUCKET_IS_METADATA(b)) {
+            if (APR_BUCKET_IS_EOS(b)) {
+                body = NULL;
+            }
+        }
+        else {
+            rv = apr_bucket_read(b, &bdata, &blen, APR_BLOCK_READ);
+            if (rv == APR_SUCCESS) {
+                if (blen > max_len) {
+                    apr_bucket_split(b, max_len);
+                    blen = max_len;
+                }
+                memcpy(rdata, bdata, blen);
+                read_len += blen;
+                max_len -= blen;
+                rdata += blen;
+            }
+            else {
+                body = NULL;
+                if (!APR_STATUS_IS_EOF(rv)) {
+                    /* everything beside EOF is an error */
+                    read_len = CURL_READFUNC_ABORT;
+                }
+            }
+            
+        }
+        apr_bucket_delete(b);
+    }
+    
+    return read_len;
+}
+
+static size_t resp_data_cb(void *data, size_t len, size_t nmemb, void *baton)
+{
+    md_curl_internals_t *internals = baton;
+    md_http_response_t *res = internals->response;
+    size_t blen = len * nmemb;
+    apr_status_t rv;
+    
+    if (res->body) {
+        if (res->req->resp_limit) {
+            apr_off_t body_len = 0;
+            apr_brigade_length(res->body, 0, &body_len);
+            if (body_len + (apr_off_t)blen > res->req->resp_limit) {
+                return 0; /* signal curl failure */
+            }
+        }
+        rv = apr_brigade_write(res->body, NULL, NULL, (const char *)data, blen);
+        if (rv != APR_SUCCESS) {
+            /* returning anything != blen will make CURL fail this */
+            return 0;
+        }
+    }
+    return blen;
+}
+
+static size_t header_cb(void *buffer, size_t elen, size_t nmemb, void *baton)
+{
+    md_curl_internals_t *internals = baton;
+    md_http_response_t *res = internals->response;
+    size_t len, clen = elen * nmemb;
+    const char *name = NULL, *value = "", *b = buffer;
+    apr_size_t i;
+    
+    len = (clen && b[clen-1] == '\n')? clen-1 : clen;
+    len = (len && b[len-1] == '\r')? len-1 : len;
+    for (i = 0; i < len; ++i) {
+        if (b[i] == ':') {
+            name = apr_pstrndup(res->req->pool, b, i);
+            ++i;
+            while (i < len && b[i] == ' ') {
+                ++i;
+            }
+            if (i < len) {
+                value = apr_pstrndup(res->req->pool, b+i, len - i);
+            }
+            break;
+        }
+    }
+    
+    if (name != NULL) {
+        apr_table_add(res->headers, name, value);
+    }
+    return clen;
+}
+
+typedef struct {
+    md_http_request_t *req;
+    struct curl_slist *hdrs;
+    apr_status_t rv;
+} curlify_hdrs_ctx;
+
+static int curlify_headers(void *baton, const char *key, const char *value)
+{
+    curlify_hdrs_ctx *ctx = baton;
+    const char *s;
+    
+    if (strchr(key, '\r') || strchr(key, '\n')
+        || strchr(value, '\r') || strchr(value, '\n')) {
+        ctx->rv = APR_EINVAL;
+        return 0;
+    }
+    s = apr_psprintf(ctx->req->pool, "%s: %s", key, value);
+    ctx->hdrs = curl_slist_append(ctx->hdrs, s);
+    return 1;
+}
+
+/* Convert timeout values for curl. Since curl uses 0 to disable
+ * timeout, return at least 1 if the apr_time_t value is non-zero. */
+static long timeout_msec(apr_time_t timeout)
+{
+    long ms = (long)apr_time_as_msec(timeout);
+    return ms? ms : (timeout? 1 : 0);
+}
+
+static long timeout_sec(apr_time_t timeout)
+{
+    long s = (long)apr_time_sec(timeout);
+    return s? s : (timeout? 1 : 0);
+}
+
+static int curl_debug_log(CURL *curl, curl_infotype type, char *data, size_t size, void *baton)
+{
+    md_http_request_t *req = baton;
+    
+    (void)curl;
+    switch (type) {
+        case CURLINFO_TEXT:
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE4, 0, req->pool, 
+                          "req[%d]: info %s", req->id, apr_pstrndup(req->pool, data, size));
+            break;
+        case CURLINFO_HEADER_OUT:
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE4, 0, req->pool, 
+                          "req[%d]: header --> %s", req->id, apr_pstrndup(req->pool, data, size));
+            break;
+        case CURLINFO_HEADER_IN:
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE4, 0, req->pool, 
+                          "req[%d]: header <-- %s", req->id, apr_pstrndup(req->pool, data, size));
+            break;
+        case CURLINFO_DATA_OUT:
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE4, 0, req->pool, 
+                          "req[%d]: data --> %ld bytes", req->id, (long)size);
+            if (md_log_is_level(req->pool, MD_LOG_TRACE5)) {
+                md_data_t d;
+                const char *s;
+                md_data_init(&d, data, size);
+                md_data_to_hex(&s, 0, req->pool, &d);
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE5, 0, req->pool, 
+                              "req[%d]: data(hex) -->  %s", req->id, s);
+            }
+            break;
+        case CURLINFO_DATA_IN:
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE4, 0, req->pool, 
+                          "req[%d]: data <-- %ld bytes", req->id, (long)size);
+            if (md_log_is_level(req->pool, MD_LOG_TRACE5)) {
+                md_data_t d;
+                const char *s;
+                md_data_init(&d, data, size);
+                md_data_to_hex(&s, 0, req->pool, &d);
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE5, 0, req->pool, 
+                              "req[%d]: data(hex) <-- %s", req->id, s);
+            }
+            break;
+        default:
+            break;
+    }
+    return 0;
+}
+
+static apr_status_t internals_setup(md_http_request_t *req)
+{
+    md_curl_internals_t *internals;
+    CURL *curl;
+    apr_status_t rv = APR_SUCCESS;
+
+    curl = md_http_get_impl_data(req->http);
+    if (!curl) {
+        md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, req->pool, "creating curl instance");
+        curl = curl_easy_init();
+        if (!curl) {
+            rv = APR_EGENERAL;
+            goto leave;
+        }
+        curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_cb);
+        curl_easy_setopt(curl, CURLOPT_HEADERDATA, NULL);
+        curl_easy_setopt(curl, CURLOPT_READFUNCTION, req_data_cb);
+        curl_easy_setopt(curl, CURLOPT_READDATA, NULL);
+        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, resp_data_cb);
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
+    }
+    else {
+        md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, req->pool, "reusing curl instance from http");
+    }
+
+    internals = apr_pcalloc(req->pool, sizeof(*internals));
+    internals->curl = curl;
+        
+    internals->response = apr_pcalloc(req->pool, sizeof(md_http_response_t));
+    internals->response->req = req;
+    internals->response->status = 400;
+    internals->response->headers = apr_table_make(req->pool, 5);
+    internals->response->body = apr_brigade_create(req->pool, req->bucket_alloc);
+    
+    curl_easy_setopt(curl, CURLOPT_URL, req->url);
+    if (!apr_strnatcasecmp("GET", req->method)) {
+        /* nop */
+    }
+    else if (!apr_strnatcasecmp("HEAD", req->method)) {
+        curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
+    }
+    else if (!apr_strnatcasecmp("POST", req->method)) {
+        curl_easy_setopt(curl, CURLOPT_POST, 1L);
+    }
+    else {
+        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, req->method);
+    }
+    curl_easy_setopt(curl, CURLOPT_HEADERDATA, internals);
+    curl_easy_setopt(curl, CURLOPT_READDATA, req->body);
+    curl_easy_setopt(curl, CURLOPT_WRITEDATA, internals);
+    
+    if (req->timeout.overall > 0) {
+        curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS, timeout_msec(req->timeout.overall));
+    }
+    if (req->timeout.connect > 0) {
+        curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS, timeout_msec(req->timeout.connect));
+    }
+    if (req->timeout.stalled > 0) {
+        curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, req->timeout.stall_bytes_per_sec);
+        curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, timeout_sec(req->timeout.stalled));
+    }
+    if (req->ca_file) {
+        curl_easy_setopt(curl, CURLOPT_CAINFO, req->ca_file);
+    }
+    if (req->unix_socket_path) {
+        curl_easy_setopt(curl, CURLOPT_UNIX_SOCKET_PATH, req->unix_socket_path);
+    }
+
+    if (req->body_len >= 0) {
+        /* set the Content-Length */
+        curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, (curl_off_t)req->body_len);
+        curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE_LARGE, (curl_off_t)req->body_len);
+    }
+    
+    if (req->user_agent) {
+        curl_easy_setopt(curl, CURLOPT_USERAGENT, req->user_agent);
+    }
+    if (req->proxy_url) {
+        curl_easy_setopt(curl, CURLOPT_PROXY, req->proxy_url);
+    }
+    if (!apr_is_empty_table(req->headers)) {
+        curlify_hdrs_ctx ctx;
+        
+        ctx.req = req;
+        ctx.hdrs = NULL;
+        ctx.rv = APR_SUCCESS;
+        apr_table_do(curlify_headers, &ctx, req->headers, NULL);
+        internals->req_hdrs = ctx.hdrs;
+        if (ctx.rv == APR_SUCCESS) {
+            curl_easy_setopt(curl, CURLOPT_HTTPHEADER, internals->req_hdrs);
+        }
+    }
+    
+    md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, req->pool, 
+                  "req[%d]: %s %s", req->id, req->method, req->url);
+    
+    if (md_log_is_level(req->pool, MD_LOG_TRACE4)) {
+        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+        curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, curl_debug_log);
+        curl_easy_setopt(curl, CURLOPT_DEBUGDATA, req);
+    }
+    
+leave:
+    req->internals = (APR_SUCCESS == rv)? internals : NULL;
+    return rv;
+}
+
+static apr_status_t update_status(md_http_request_t *req)
+{
+    md_curl_internals_t *internals = req->internals;
+    long l;
+    apr_status_t rv = APR_SUCCESS;
+
+    if (internals) {
+        rv = curl_status(curl_easy_getinfo(internals->curl, CURLINFO_RESPONSE_CODE, &l));
+        if (APR_SUCCESS == rv) {
+            internals->response->status = (int)l;
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, req->pool,
+                          "req[%d]: http status is %d",
+                          req->id, internals->response->status);
+        }
+    }
+    return rv;
+}
+
+static void fire_status(md_http_request_t *req, apr_status_t rv)
+{
+    md_curl_internals_t *internals = req->internals;
+        
+    if (internals && !internals->status_fired) {
+        internals->status_fired = 1;
+        
+        md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, req->pool, 
+                      "req[%d] fire callbacks", req->id);
+        if ((APR_SUCCESS == rv) && req->cb.on_response) {
+            rv = req->cb.on_response(internals->response, req->cb.on_response_data);
+        }
+    
+        internals->rv = rv;
+        if (req->cb.on_status) {
+            req->cb.on_status(req, rv, req->cb.on_status_data);
+        }
+    }
+}
+
+static apr_status_t md_curl_perform(md_http_request_t *req)
+{
+    apr_status_t rv = APR_SUCCESS;
+    CURLcode curle;
+    md_curl_internals_t *internals;
+    long l;
+
+    if (APR_SUCCESS != (rv = internals_setup(req))) goto leave;
+    internals = req->internals;
+    
+    curle = curl_easy_perform(internals->curl);
+    
+    rv = curl_status(curle);
+    if (APR_SUCCESS != rv) {
+        md_log_perror(MD_LOG_MARK, MD_LOG_DEBUG, rv, req->pool, 
+                      "request failed(%d): %s", curle, curl_easy_strerror(curle));
+        goto leave;
+    }
+    
+    rv = curl_status(curl_easy_getinfo(internals->curl, CURLINFO_RESPONSE_CODE, &l));
+    if (APR_SUCCESS == rv) {
+        internals->response->status = (int)l;
+    }
+    md_log_perror(MD_LOG_MARK, MD_LOG_TRACE1, rv, req->pool, "request <-- %d", 
+                  internals->response->status);
+    
+    if (req->cb.on_response) {
+        rv = req->cb.on_response(internals->response, req->cb.on_response_data);
+        req->cb.on_response = NULL;
+    }
+    
+leave:
+    fire_status(req, rv);
+    md_http_req_destroy(req);
+    return rv;
+}
+
+static md_http_request_t *find_curl_request(apr_array_header_t *requests, CURL *curl)
+{
+    md_http_request_t *req;
+    md_curl_internals_t *internals;
+    int i;
+    
+    for (i = 0; i < requests->nelts; ++i) {
+        req = APR_ARRAY_IDX(requests, i, md_http_request_t*);
+        internals = req->internals;
+        if (internals && internals->curl == curl) {
+            return req;
+        }
+    }
+    return NULL;
+}
+
+static void add_to_curlm(md_http_request_t *req, CURLM *curlm)
+{
+    md_curl_internals_t *internals = req->internals;
+    
+    assert(curlm);
+    assert(internals);
+    if (internals->curlm == NULL) {
+        internals->curlm = curlm;
+    }
+    assert(internals->curlm == curlm);
+    curl_multi_add_handle(curlm, internals->curl);
+}
+
+static void remove_from_curlm_and_destroy(md_http_request_t *req, CURLM *curlm)
+{
+    md_curl_internals_t *internals = req->internals;
+
+    assert(curlm);
+    assert(internals);
+    assert(internals->curlm == curlm);
+    curl_multi_remove_handle(curlm, internals->curl);
+    internals->curlm = NULL;
+    md_http_req_destroy(req);
+}
+    
+static apr_status_t md_curl_multi_perform(md_http_t *http, apr_pool_t *p,
+                                          md_http_next_req *nextreq, void *baton)
+{
+    md_http_t *sub_http;
+    md_http_request_t *req;
+    CURLM *curlm = NULL;
+    CURLMcode mc;
+    struct CURLMsg *curlmsg;
+    apr_array_header_t *http_spares;
+    apr_array_header_t *requests;
+    int i, running, numfds, slowdown, msgcount;
+    apr_status_t rv;
+    
+    http_spares = apr_array_make(p, 10, sizeof(md_http_t*));
+    requests = apr_array_make(p, 10, sizeof(md_http_request_t*));
+    curlm = curl_multi_init();
+    if (!curlm) {
+        rv = APR_ENOMEM;
+        goto leave;
+    }
+    
+    running = 1;
+    slowdown = 0;
+    while(1) {
+        while (1) {
+            /* fetch as many requests as nextreq gives us */
+            if (http_spares->nelts > 0) {
+                sub_http = *(md_http_t **)(apr_array_pop(http_spares));
+            }
+            else {
+                rv = md_http_clone(&sub_http, p, http);
+                if (APR_SUCCESS != rv) {
+                    md_log_perror(MD_LOG_MARK, MD_LOG_ERR, rv, p,
+                                  "multi_perform[%d reqs]: setup failed", requests->nelts);
+                    goto leave;
+                }
+            }
+
+            rv = nextreq(&req, baton, sub_http, requests->nelts);
+            if (APR_STATUS_IS_ENOENT(rv)) {
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, p,
+                              "multi_perform[%d reqs]: no more requests", requests->nelts);
+                if (!requests->nelts) {
+                    goto leave;
+                }
+                break;
+            }
+            else if (APR_SUCCESS != rv) {
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p,
+                              "multi_perform[%d reqs]: nextreq() failed", requests->nelts);
+                APR_ARRAY_PUSH(http_spares, md_http_t*) = sub_http;
+                goto leave;
+            }
+
+            if (APR_SUCCESS != (rv = internals_setup(req))) {
+                if (req->cb.on_status) req->cb.on_status(req, rv, req->cb.on_status_data);
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p,
+                              "multi_perform[%d reqs]: setup failed", requests->nelts);
+                APR_ARRAY_PUSH(http_spares, md_http_t*) = sub_http;
+                goto leave;
+            }
+
+            APR_ARRAY_PUSH(requests, md_http_request_t*) = req;
+            add_to_curlm(req, curlm);
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p,
+                          "multi_perform[%d reqs]: added request", requests->nelts);
+        }
+    
+        mc = curl_multi_perform(curlm, &running);
+        if (CURLM_OK == mc) {
+            mc = curl_multi_wait(curlm, NULL, 0, 1000, &numfds);
+            if (numfds) slowdown = 0;
+        }
+        if (CURLM_OK != mc) {
+            rv = APR_ECONNABORTED;
+            md_log_perror(MD_LOG_MARK, MD_LOG_DEBUG, rv, p, 
+                          "multi_perform[%d reqs] failed(%d): %s", 
+                          requests->nelts, mc, curl_multi_strerror(mc));
+            goto leave;
+        }
+        if (!numfds) {
+            /* no activity on any connection, timeout */
+            md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, p, 
+                          "multi_perform[%d reqs]: slowdown %d", requests->nelts, slowdown);
+            if (slowdown) apr_sleep(apr_time_from_msec(100));
+            ++slowdown;
+        }
+
+        /* process status messages, e.g. that a request is done */
+        while (running < requests->nelts) {
+            curlmsg = curl_multi_info_read(curlm, &msgcount);
+            if (!curlmsg) break;
+            if (curlmsg->msg == CURLMSG_DONE) {
+                req = find_curl_request(requests, curlmsg->easy_handle);
+                if (req) {
+                    md_log_perror(MD_LOG_MARK, MD_LOG_TRACE2, 0, p,
+                                  "multi_perform[%d reqs]: req[%d] done", 
+                                  requests->nelts, req->id);
+                    update_status(req);
+                    fire_status(req, curl_status(curlmsg->data.result));
+                    md_array_remove(requests, req);
+                    sub_http = req->http;
+                    APR_ARRAY_PUSH(http_spares, md_http_t*) = sub_http;
+                    remove_from_curlm_and_destroy(req, curlm);
+                }
+                else {
+                    md_log_perror(MD_LOG_MARK, MD_LOG_DEBUG, 0, p, 
+                                  "multi_perform[%d reqs]: req done, but not found by handle", 
+                                  requests->nelts);
+                }
+            }
+        }
+    };
+
+leave:
+    md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, rv, p, 
+                  "multi_perform[%d reqs]: leaving", requests->nelts);
+    for (i = 0; i < requests->nelts; ++i) {
+        req = APR_ARRAY_IDX(requests, i, md_http_request_t*);
+        fire_status(req, APR_SUCCESS);
+        sub_http = req->http;
+        APR_ARRAY_PUSH(http_spares, md_http_t*) = sub_http;
+        remove_from_curlm_and_destroy(req, curlm);
+    }
+    if (curlm) curl_multi_cleanup(curlm);
+    return rv;
+}
+
+static int initialized;
+
+static apr_status_t md_curl_init(void) {
+    if (!initialized) {
+        initialized = 1;
+        curl_global_init(CURL_GLOBAL_DEFAULT);
+    }
+    return APR_SUCCESS;
+}
+
+static void md_curl_req_cleanup(md_http_request_t *req) 
+{
+    md_curl_internals_t *internals = req->internals;
+    if (internals) {
+        if (internals->curl) {
+            CURL *curl = md_http_get_impl_data(req->http);
+            if (curl == internals->curl) {
+                /* NOP: we have this curl at the md_http_t already */
+            }
+            else if (!curl) {
+                /* no curl at the md_http_t yet, install this one */
+                md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, req->pool, "register curl instance at http");
+                md_http_set_impl_data(req->http, internals->curl);
+            }
+            else {
+                /* There already is a curl at the md_http_t and it's not this one. */
+                curl_easy_cleanup(internals->curl);
+            }
+        }
+        if (internals->req_hdrs) curl_slist_free_all(internals->req_hdrs);
+        req->internals = NULL;
+    }
+}
+
+static void md_curl_cleanup(md_http_t *http, apr_pool_t *pool)
+{
+    CURL *curl;
+
+    curl = md_http_get_impl_data(http);
+    if (curl) {
+        md_log_perror(MD_LOG_MARK, MD_LOG_TRACE3, 0, pool, "cleanup curl instance");
+        md_http_set_impl_data(http, NULL);
+        curl_easy_cleanup(curl);
+    }
+}
+
+static md_http_impl_t impl = {
+    md_curl_init,
+    md_curl_req_cleanup,
+    md_curl_perform,
+    md_curl_multi_perform,
+    md_curl_cleanup,
+};
+
+md_http_impl_t * md_curl_get_impl(apr_pool_t *p)
+{
+    /* trigger early global curl init, before we are down a rabbit hole */
+    (void)p;
+    md_curl_init();
+    return &impl;
+}