Adding upstream version 2.4.57.upstream/2.4.57upstream

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

1 files changed, 920 insertions, 0 deletions

diff --git a/modules/cluster/mod_heartmonitor.c b/modules/cluster/mod_heartmonitor.c
new file mode 100644
index 0000000..53b6504
--- /dev/null
+++ b/modules/cluster/mod_heartmonitor.c
@@ -0,0 +1,920 @@
+/* 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 "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "http_core.h"
+#include "http_protocol.h"
+#include "apr_strings.h"
+#include "apr_hash.h"
+#include "apr_time.h"
+#include "ap_mpm.h"
+#include "scoreboard.h"
+#include "mod_watchdog.h"
+#include "ap_slotmem.h"
+#include "heartbeat.h"
+
+
+#ifndef HM_UPDATE_SEC
+/* How often we update the stats file */
+/* TODO: Make a runtime config */
+#define HM_UPDATE_SEC (5)
+#endif
+
+#define HM_WATHCHDOG_NAME ("_heartmonitor_")
+
+static const ap_slotmem_provider_t *storage = NULL;
+static ap_slotmem_instance_t *slotmem = NULL;
+static int maxworkers = 10;
+
+module AP_MODULE_DECLARE_DATA heartmonitor_module;
+
+typedef struct hm_server_t
+{
+    const char *ip;
+    int busy;
+    int ready;
+    unsigned int port;
+    apr_time_t seen;
+} hm_server_t;
+
+typedef struct hm_ctx_t
+{
+    int active;
+    const char *storage_path;
+    ap_watchdog_t *watchdog;
+    apr_interval_time_t interval;
+    apr_sockaddr_t *mcast_addr;
+    apr_status_t status;
+    volatile int keep_running;
+    apr_socket_t *sock;
+    apr_pool_t *p;
+    apr_hash_t *servers;
+    server_rec *s;
+} hm_ctx_t;
+
+typedef struct hm_slot_server_ctx_t {
+  hm_server_t *s;
+  int found;
+  unsigned int item_id;
+} hm_slot_server_ctx_t;
+
+static apr_status_t hm_listen(hm_ctx_t *ctx)
+{
+    apr_status_t rv;
+
+    rv = apr_socket_create(&ctx->sock, ctx->mcast_addr->family,
+                           SOCK_DGRAM, APR_PROTO_UDP, ctx->p);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02068)
+                     "Failed to create listening socket.");
+        return rv;
+    }
+
+    rv = apr_socket_opt_set(ctx->sock, APR_SO_REUSEADDR, 1);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02069)
+                     "Failed to set APR_SO_REUSEADDR to 1 on socket.");
+        return rv;
+    }
+
+
+    rv = apr_socket_opt_set(ctx->sock, APR_SO_NONBLOCK, 1);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02070)
+                     "Failed to set APR_SO_NONBLOCK to 1 on socket.");
+        return rv;
+    }
+
+    rv = apr_socket_bind(ctx->sock, ctx->mcast_addr);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02071)
+                     "Failed to bind on socket.");
+        return rv;
+    }
+
+    rv = apr_mcast_join(ctx->sock, ctx->mcast_addr, NULL, NULL);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02072)
+                     "Failed to join multicast group");
+        return rv;
+    }
+
+    rv = apr_mcast_loopback(ctx->sock, 1);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02073)
+                     "Failed to accept localhost mulitcast on socket.");
+        return rv;
+    }
+
+    return APR_SUCCESS;
+}
+
+/* XXX: The same exists in mod_lbmethod_heartbeat.c where it is named argstr_to_table */
+static void qs_to_table(const char *input, apr_table_t *parms,
+                        apr_pool_t *p)
+{
+    char *key;
+    char *value;
+    char *query_string;
+    char *strtok_state;
+
+    if (input == NULL) {
+        return;
+    }
+
+    query_string = apr_pstrdup(p, input);
+
+    key = apr_strtok(query_string, "&", &strtok_state);
+    while (key) {
+        value = strchr(key, '=');
+        if (value) {
+            *value = '\0';      /* Split the string in two */
+            value++;            /* Skip passed the = */
+        }
+        else {
+            value = "1";
+        }
+        ap_unescape_url(key);
+        ap_unescape_url(value);
+        apr_table_set(parms, key, value);
+        /*
+           ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(03182)
+           "Found query arg: %s = %s", key, value);
+         */
+        key = apr_strtok(NULL, "&", &strtok_state);
+    }
+}
+
+
+#define SEEN_TIMEOUT (30)
+
+/* Store in the slotmem */
+static apr_status_t hm_update(void* mem, void *data, apr_pool_t *p)
+{
+    hm_slot_server_t *old = (hm_slot_server_t *) mem;
+    hm_slot_server_ctx_t *s = (hm_slot_server_ctx_t *) data;
+    hm_server_t *new = s->s;
+    if (strcmp(old->ip, new->ip)==0) {
+        s->found = 1;
+        old->busy = new->busy;
+        old->ready = new->ready;
+        old->seen = new->seen;
+    }
+    return APR_SUCCESS;
+}
+/* Read the id corresponding to the entry in the slotmem */
+static apr_status_t hm_readid(void* mem, void *data, apr_pool_t *p)
+{
+    hm_slot_server_t *old = (hm_slot_server_t *) mem;
+    hm_slot_server_ctx_t *s = (hm_slot_server_ctx_t *) data;
+    hm_server_t *new = s->s;
+    if (strcmp(old->ip, new->ip)==0) {
+        s->found = 1;
+        s->item_id = old->id;
+    }
+    return APR_SUCCESS;
+}
+/* update the entry or create it if not existing */
+static  apr_status_t  hm_slotmem_update_stat(hm_server_t *s, apr_pool_t *pool)
+{
+    /* We call do_all (to try to update) otherwise grab + put */
+    hm_slot_server_ctx_t ctx;
+    ctx.s = s;
+    ctx.found = 0;
+    storage->doall(slotmem, hm_update, &ctx, pool);
+    if (!ctx.found) {
+        unsigned int i;
+        hm_slot_server_t hmserver;
+        memset(&hmserver, 0, sizeof(hmserver));
+        apr_cpystrn(hmserver.ip, s->ip, sizeof(hmserver.ip));
+        hmserver.busy = s->busy;
+        hmserver.ready = s->ready;
+        hmserver.seen = s->seen;
+        /* XXX locking for grab() / put() */
+        storage->grab(slotmem, &i);
+        hmserver.id = i;
+        storage->put(slotmem, i, (unsigned char *)&hmserver, sizeof(hmserver));
+    }
+    return APR_SUCCESS;
+}
+static  apr_status_t  hm_slotmem_remove_stat(hm_server_t *s, apr_pool_t *pool)
+{
+    hm_slot_server_ctx_t ctx;
+    ctx.s = s;
+    ctx.found = 0;
+    storage->doall(slotmem, hm_readid, &ctx, pool);
+    if (ctx.found) {
+        storage->release(slotmem, ctx.item_id);
+    }
+    return APR_SUCCESS;
+}
+static apr_status_t hm_file_update_stat(hm_ctx_t *ctx, hm_server_t *s, apr_pool_t *pool)
+{
+    apr_status_t rv;
+    apr_file_t *fp;
+    apr_file_t *fpin;
+    apr_time_t now;
+    apr_time_t fage;
+    apr_finfo_t fi;
+    int updated = 0;
+    char *path = apr_pstrcat(pool, ctx->storage_path, ".tmp.XXXXXX", NULL);
+
+
+    /* TODO: Update stats file (!) */
+    rv = apr_file_mktemp(&fp, path, APR_CREATE | APR_WRITE, pool);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02074)
+                     "Unable to open tmp file: %s", path);
+        return rv;
+    }
+    rv = apr_file_open(&fpin, ctx->storage_path, APR_READ|APR_BINARY|APR_BUFFERED,
+                       APR_OS_DEFAULT, pool);
+
+    now = apr_time_now();
+    if (rv == APR_SUCCESS) {
+        char *t;
+        apr_table_t *hbt = apr_table_make(pool, 10);
+        apr_bucket_alloc_t *ba;
+        apr_bucket_brigade *bb;
+        apr_bucket_brigade *tmpbb;
+
+        rv = apr_file_info_get(&fi, APR_FINFO_SIZE | APR_FINFO_MTIME, fpin);
+        if (rv) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02075)
+                         "Unable to read file: %s", ctx->storage_path);
+            return rv;
+        }
+
+        /* Read the file and update the line corresponding to the node */
+        ba = apr_bucket_alloc_create(pool);
+        bb = apr_brigade_create(pool, ba);
+        apr_brigade_insert_file(bb, fpin, 0, fi.size, pool);
+        tmpbb = apr_brigade_create(pool, ba);
+        fage = apr_time_sec(now - fi.mtime);
+        do {
+            char buf[4096];
+            const char *ip;
+            apr_size_t bsize = sizeof(buf);
+
+            apr_brigade_cleanup(tmpbb);
+            if (APR_BRIGADE_EMPTY(bb)) {
+                break;
+            }
+            rv = apr_brigade_split_line(tmpbb, bb,
+                                        APR_BLOCK_READ, sizeof(buf));
+
+            if (rv) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02076)
+                             "Unable to read from file: %s", ctx->storage_path);
+                return rv;
+            }
+
+            apr_brigade_flatten(tmpbb, buf, &bsize);
+            if (bsize == 0) {
+                break;
+            }
+            buf[bsize - 1] = 0;
+            t = strchr(buf, ' ');
+            if (t) {
+                ip = apr_pstrmemdup(pool, buf, t - buf);
+            }
+            else {
+                ip = NULL;
+            }
+
+            if (!ip || buf[0] == '#') {
+                /* copy things we can't process */
+                apr_file_printf(fp, "%s\n", buf);
+            }
+            else if (strcmp(ip, s->ip) != 0 ) {
+                hm_server_t node;
+                apr_time_t seen;
+                const char *val;
+
+                /* Update seen time according to the last file modification */
+                apr_table_clear(hbt);
+                qs_to_table(apr_pstrdup(pool, t), hbt, pool);
+                if ((val = apr_table_get(hbt, "busy"))) {
+                    node.busy = atoi(val);
+                }
+                else {
+                    node.busy = 0;
+                }
+
+                if ((val = apr_table_get(hbt, "ready"))) {
+                    node.ready = atoi(val);
+                }
+                else {
+                    node.ready = 0;
+                }
+
+                if ((val = apr_table_get(hbt, "lastseen"))) {
+                    node.seen = atoi(val);
+                }
+                else {
+                    node.seen = SEEN_TIMEOUT;
+                }
+                seen = fage + node.seen;
+
+                if ((val = apr_table_get(hbt, "port"))) {
+                    node.port = atoi(val);
+                }
+                else {
+                    node.port = 80;
+                }
+                apr_file_printf(fp, "%s &ready=%u&busy=%u&lastseen=%u&port=%u\n",
+                                ip, node.ready, node.busy, (unsigned int) seen, node.port);
+            }
+            else {
+                apr_time_t seen;
+                seen = apr_time_sec(now - s->seen);
+                apr_file_printf(fp, "%s &ready=%u&busy=%u&lastseen=%u&port=%u\n",
+                                s->ip, s->ready, s->busy, (unsigned int) seen, s->port);
+                updated = 1;
+            }
+        } while (1);
+    }
+
+    if (!updated) {
+        apr_time_t seen;
+        seen = apr_time_sec(now - s->seen);
+        apr_file_printf(fp, "%s &ready=%u&busy=%u&lastseen=%u&port=%u\n",
+                        s->ip, s->ready, s->busy, (unsigned int) seen, s->port);
+    }
+
+    rv = apr_file_flush(fp);
+    if (rv) {
+      ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02077)
+                   "Unable to flush file: %s", path);
+      return rv;
+    }
+
+    rv = apr_file_close(fp);
+    if (rv) {
+      ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02078)
+                   "Unable to close file: %s", path);
+      return rv;
+    }
+
+    rv = apr_file_perms_set(path,
+                            APR_FPROT_UREAD | APR_FPROT_GREAD |
+                            APR_FPROT_WREAD);
+    if (rv && rv != APR_INCOMPLETE && rv != APR_ENOTIMPL) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02079)
+                     "Unable to set file permissions on %s",
+                     path);
+        return rv;
+    }
+
+    rv = apr_file_rename(path, ctx->storage_path, pool);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02080)
+                     "Unable to move file: %s -> %s", path,
+                     ctx->storage_path);
+        return rv;
+    }
+
+    return APR_SUCCESS;
+}
+static  apr_status_t  hm_update_stat(hm_ctx_t *ctx, hm_server_t *s, apr_pool_t *pool)
+{
+    if (slotmem)
+        return hm_slotmem_update_stat(s, pool);
+    else
+        return hm_file_update_stat(ctx, s, pool);
+}
+
+/* Store in a file */
+static apr_status_t hm_file_update_stats(hm_ctx_t *ctx, apr_pool_t *p)
+{
+    apr_status_t rv;
+    apr_file_t *fp;
+    apr_hash_index_t *hi;
+    apr_time_t now;
+    char *path = apr_pstrcat(p, ctx->storage_path, ".tmp.XXXXXX", NULL);
+    /* TODO: Update stats file (!) */
+    rv = apr_file_mktemp(&fp, path, APR_CREATE | APR_WRITE, p);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02081)
+                     "Unable to open tmp file: %s", path);
+        return rv;
+    }
+
+    now = apr_time_now();
+    for (hi = apr_hash_first(p, ctx->servers);
+         hi != NULL; hi = apr_hash_next(hi)) {
+        hm_server_t *s = NULL;
+        apr_time_t seen;
+        apr_hash_this(hi, NULL, NULL, (void **) &s);
+        seen = apr_time_sec(now - s->seen);
+        if (seen > SEEN_TIMEOUT) {
+            /*
+             * Skip this entry from the heartbeat file -- when it comes back,
+             * we will reuse the memory...
+             */
+        }
+        else {
+            apr_file_printf(fp, "%s &ready=%u&busy=%u&lastseen=%u&port=%u\n",
+                            s->ip, s->ready, s->busy, (unsigned int) seen, s->port);
+        }
+    }
+
+    rv = apr_file_flush(fp);
+    if (rv) {
+      ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02082)
+                   "Unable to flush file: %s", path);
+      return rv;
+    }
+
+    rv = apr_file_close(fp);
+    if (rv) {
+      ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02083)
+                   "Unable to close file: %s", path);
+      return rv;
+    }
+
+    rv = apr_file_perms_set(path,
+                            APR_FPROT_UREAD | APR_FPROT_GREAD |
+                            APR_FPROT_WREAD);
+    if (rv && rv != APR_INCOMPLETE && rv != APR_ENOTIMPL) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02084)
+                     "Unable to set file permissions on %s",
+                     path);
+        return rv;
+    }
+
+    rv = apr_file_rename(path, ctx->storage_path, p);
+
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02085)
+                     "Unable to move file: %s -> %s", path,
+                     ctx->storage_path);
+        return rv;
+    }
+
+    return APR_SUCCESS;
+}
+/* Store in a slotmem */
+static apr_status_t hm_slotmem_update_stats(hm_ctx_t *ctx, apr_pool_t *p)
+{
+    apr_status_t rv;
+    apr_time_t now;
+    apr_hash_index_t *hi;
+    now = apr_time_now();
+    for (hi = apr_hash_first(p, ctx->servers);
+         hi != NULL; hi = apr_hash_next(hi)) {
+        hm_server_t *s = NULL;
+        apr_time_t seen;
+        apr_hash_this(hi, NULL, NULL, (void **) &s);
+        seen = apr_time_sec(now - s->seen);
+        if (seen > SEEN_TIMEOUT) {
+            /* remove it */
+            rv = hm_slotmem_remove_stat(s, p);
+        } else {
+            /* update it */
+            rv = hm_slotmem_update_stat(s, p);
+        }
+        if (rv !=APR_SUCCESS)
+            return rv;
+    }
+    return APR_SUCCESS;
+}
+/* Store/update the stats */
+static apr_status_t hm_update_stats(hm_ctx_t *ctx, apr_pool_t *p)
+{
+    if (slotmem)
+        return hm_slotmem_update_stats(ctx, p);
+    else
+        return hm_file_update_stats(ctx, p);
+}
+
+static hm_server_t *hm_get_server(hm_ctx_t *ctx, const char *ip, const int port)
+{
+    hm_server_t *s;
+
+    s = apr_hash_get(ctx->servers, ip, APR_HASH_KEY_STRING);
+
+    if (s == NULL) {
+        s = apr_palloc(ctx->p, sizeof(hm_server_t));
+        s->ip = apr_pstrdup(ctx->p, ip);
+        s->port = port;
+        s->ready = 0;
+        s->busy = 0;
+        s->seen = 0;
+        apr_hash_set(ctx->servers, s->ip, APR_HASH_KEY_STRING, s);
+    }
+
+    return s;
+}
+
+/* Process a message received from a backend node */
+static void hm_processmsg(hm_ctx_t *ctx, apr_pool_t *p,
+                          apr_sockaddr_t *from, char *buf, apr_size_t len)
+{
+    apr_table_t *tbl;
+
+    buf[len] = '\0';
+
+    tbl = apr_table_make(p, 10);
+
+    qs_to_table(buf, tbl, p);
+
+    if (apr_table_get(tbl, "v") != NULL &&
+        apr_table_get(tbl, "busy") != NULL &&
+        apr_table_get(tbl, "ready") != NULL) {
+        char *ip;
+        int port = 80;
+        hm_server_t *s;
+        /* TODO: REMOVE ME BEFORE PRODUCTION (????) */
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ctx->s, APLOGNO(02086)
+                     "%pI busy=%s ready=%s", from,
+                     apr_table_get(tbl, "busy"), apr_table_get(tbl, "ready"));
+
+        apr_sockaddr_ip_get(&ip, from);
+
+        if (apr_table_get(tbl, "port") != NULL)
+            port = atoi(apr_table_get(tbl, "port"));
+
+        s = hm_get_server(ctx, ip, port);
+
+        s->busy = atoi(apr_table_get(tbl, "busy"));
+        s->ready = atoi(apr_table_get(tbl, "ready"));
+        s->seen = apr_time_now();
+    }
+    else {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, 0, ctx->s, APLOGNO(02087)
+                     "malformed message from %pI",
+                     from);
+    }
+
+}
+/* Read message from multicast socket */
+#define MAX_MSG_LEN (1000)
+static apr_status_t hm_recv(hm_ctx_t *ctx, apr_pool_t *p)
+{
+    char buf[MAX_MSG_LEN + 1];
+    apr_sockaddr_t from;
+    apr_size_t len = MAX_MSG_LEN;
+    apr_status_t rv;
+
+    from.pool = p;
+
+    rv = apr_socket_recvfrom(&from, ctx->sock, 0, buf, &len);
+
+    if (APR_STATUS_IS_EAGAIN(rv)) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02088) "would block");
+        return APR_SUCCESS;
+    }
+    else if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02089) "recvfrom failed");
+        return rv;
+    }
+
+    hm_processmsg(ctx, p, &from, buf, len);
+
+    return rv;
+}
+
+static apr_status_t hm_watchdog_callback(int state, void *data,
+                                         apr_pool_t *pool)
+{
+    apr_status_t rv = APR_SUCCESS;
+    apr_time_t cur, now;
+    hm_ctx_t *ctx = (hm_ctx_t *)data;
+
+    if (!ctx->active) {
+        return rv;
+    }
+
+    switch (state) {
+        case AP_WATCHDOG_STATE_STARTING:
+            rv = hm_listen(ctx);
+            if (rv) {
+                ctx->status = rv;
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ctx->s, APLOGNO(02090)
+                             "Unable to listen for connections!");
+            }
+            else {
+                ctx->keep_running = 1;
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ctx->s, APLOGNO(02091)
+                             "%s listener started.",
+                             HM_WATHCHDOG_NAME);
+            }
+        break;
+        case AP_WATCHDOG_STATE_RUNNING:
+            /* store in the slotmem or in the file depending on configuration */
+            hm_update_stats(ctx, pool);
+            cur = now = apr_time_sec(apr_time_now());
+
+            while ((now - cur) < apr_time_sec(ctx->interval)) {
+                int n;
+                apr_status_t rc;
+                apr_pool_t *p;
+                apr_pollfd_t pfd;
+                apr_interval_time_t timeout;
+
+                apr_pool_create(&p, pool);
+                apr_pool_tag(p, "hm_running");
+
+                pfd.desc_type = APR_POLL_SOCKET;
+                pfd.desc.s = ctx->sock;
+                pfd.p = p;
+                pfd.reqevents = APR_POLLIN;
+
+                timeout = apr_time_from_sec(1);
+
+                rc = apr_poll(&pfd, 1, &n, timeout);
+
+                if (!ctx->keep_running) {
+                    apr_pool_destroy(p);
+                    break;
+                }
+                if (rc == APR_SUCCESS && (pfd.rtnevents & APR_POLLIN)) {
+                    hm_recv(ctx, p);
+                }
+                now = apr_time_sec(apr_time_now());
+                apr_pool_destroy(p);
+            }
+        break;
+        case AP_WATCHDOG_STATE_STOPPING:
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ctx->s, APLOGNO(02092)
+                         "stopping %s listener.",
+                         HM_WATHCHDOG_NAME);
+
+            ctx->keep_running = 0;
+            if (ctx->sock) {
+                apr_socket_close(ctx->sock);
+                ctx->sock = NULL;
+            }
+        break;
+    }
+    return rv;
+}
+
+static int hm_post_config(apr_pool_t *p, apr_pool_t *plog,
+                          apr_pool_t *ptemp, server_rec *s)
+{
+    apr_status_t rv;
+    hm_ctx_t *ctx = ap_get_module_config(s->module_config,
+                                         &heartmonitor_module);
+    APR_OPTIONAL_FN_TYPE(ap_watchdog_get_instance) *hm_watchdog_get_instance;
+    APR_OPTIONAL_FN_TYPE(ap_watchdog_register_callback) *hm_watchdog_register_callback;
+
+    hm_watchdog_get_instance = APR_RETRIEVE_OPTIONAL_FN(ap_watchdog_get_instance);
+    hm_watchdog_register_callback = APR_RETRIEVE_OPTIONAL_FN(ap_watchdog_register_callback);
+    if (!hm_watchdog_get_instance || !hm_watchdog_register_callback) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s, APLOGNO(02093)
+                     "mod_watchdog is required");
+        return !OK;
+    }
+
+    /* Create the slotmem */
+    if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_CONFIG) {
+        /* this is the real thing */
+        if (maxworkers) {
+            storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shm",
+                                         AP_SLOTMEM_PROVIDER_VERSION);
+            if (!storage) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(02284)
+                             "failed to lookup provider 'shm' for '%s', "
+                             "maybe you need to load mod_slotmem_shm?",
+                             AP_SLOTMEM_PROVIDER_GROUP);
+                return !OK;
+            }
+            storage->create(&slotmem, "mod_heartmonitor", sizeof(hm_slot_server_t), maxworkers, AP_SLOTMEM_TYPE_PREGRAB, p);
+            if (!slotmem) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(02285)
+                             "slotmem_create for status failed");
+                return !OK;
+            }
+        }
+    }
+
+    if (!ctx->active) {
+        return OK;
+    }
+    rv = hm_watchdog_get_instance(&ctx->watchdog,
+                                  HM_WATHCHDOG_NAME,
+                                  0, 1, p);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s, APLOGNO(02094)
+                     "Failed to create watchdog instance (%s)",
+                     HM_WATHCHDOG_NAME);
+        return !OK;
+    }
+    /* Register a callback with zero interval. */
+    rv = hm_watchdog_register_callback(ctx->watchdog,
+                                       0,
+                                       ctx,
+                                       hm_watchdog_callback);
+    if (rv) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s, APLOGNO(02095)
+                     "Failed to register watchdog callback (%s)",
+                     HM_WATHCHDOG_NAME);
+        return !OK;
+    }
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02096)
+                 "wd callback %s", HM_WATHCHDOG_NAME);
+    return OK;
+}
+
+static int hm_handler(request_rec *r)
+{
+    apr_bucket_brigade *input_brigade;
+    apr_size_t len;
+    char *buf;
+    apr_status_t status;
+    apr_table_t *tbl;
+    hm_server_t hmserver;
+    char *ip;
+    hm_ctx_t *ctx;
+
+    if (strcmp(r->handler, "heartbeat")) {
+        return DECLINED;
+    }
+    if (r->method_number != M_POST) {
+        return HTTP_METHOD_NOT_ALLOWED;
+    }
+
+    len = MAX_MSG_LEN;
+    ctx = ap_get_module_config(r->server->module_config,
+            &heartmonitor_module);
+
+    buf = apr_pcalloc(r->pool, MAX_MSG_LEN);
+    input_brigade = apr_brigade_create(r->connection->pool, r->connection->bucket_alloc);
+    status = ap_get_brigade(r->input_filters, input_brigade, AP_MODE_READBYTES, APR_BLOCK_READ, MAX_MSG_LEN);
+    if (status != APR_SUCCESS) {
+        return ap_map_http_request_error(status, HTTP_BAD_REQUEST);
+    }
+    apr_brigade_flatten(input_brigade, buf, &len);
+
+    /* we can't use hm_processmsg because it uses hm_get_server() */
+    buf[len] = '\0';
+    tbl = apr_table_make(r->pool, 10);
+    qs_to_table(buf, tbl, r->pool);
+    apr_sockaddr_ip_get(&ip, r->connection->client_addr);
+    hmserver.ip = ip;
+    hmserver.port = 80;
+    if (apr_table_get(tbl, "port") != NULL)
+        hmserver.port = atoi(apr_table_get(tbl, "port"));
+    hmserver.busy = atoi(apr_table_get(tbl, "busy"));
+    hmserver.ready = atoi(apr_table_get(tbl, "ready"));
+    hmserver.seen = apr_time_now();
+    hm_update_stat(ctx, &hmserver, r->pool);
+
+    ap_set_content_type(r, "text/plain");
+    ap_set_content_length(r, 2);
+    ap_rputs("OK", r);
+    ap_rflush(r);
+
+    return OK;
+}
+
+static void hm_register_hooks(apr_pool_t *p)
+{
+    static const char * const aszSucc[]={ "mod_proxy.c", NULL };
+    ap_hook_post_config(hm_post_config, NULL, NULL, APR_HOOK_MIDDLE);
+
+    ap_hook_handler(hm_handler, NULL, aszSucc, APR_HOOK_FIRST);
+}
+
+static void *hm_create_config(apr_pool_t *p, server_rec *s)
+{
+    hm_ctx_t *ctx = (hm_ctx_t *) apr_palloc(p, sizeof(hm_ctx_t));
+
+    ctx->active = 0;
+    ctx->storage_path = ap_runtime_dir_relative(p, DEFAULT_HEARTBEAT_STORAGE);
+    /* TODO: Add directive for tuning the update interval
+     */
+    ctx->interval = apr_time_from_sec(HM_UPDATE_SEC);
+    ctx->s = s;
+    apr_pool_create(&ctx->p, p);
+    apr_pool_tag(ctx->p, "hm_ctx");
+    ctx->servers = apr_hash_make(ctx->p);
+
+    return ctx;
+}
+
+static const char *cmd_hm_storage(cmd_parms *cmd,
+                                  void *dconf, const char *path)
+{
+    apr_pool_t *p = cmd->pool;
+    hm_ctx_t *ctx =
+        (hm_ctx_t *) ap_get_module_config(cmd->server->module_config,
+                                          &heartmonitor_module);
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+
+    if (err != NULL) {
+        return err;
+    }
+
+    ctx->storage_path = ap_runtime_dir_relative(p, path);
+
+    return NULL;
+}
+
+static const char *cmd_hm_listen(cmd_parms *cmd,
+                                 void *dconf, const char *mcast_addr)
+{
+    apr_status_t rv;
+    char *host_str;
+    char *scope_id;
+    apr_port_t port = 0;
+    apr_pool_t *p = cmd->pool;
+    hm_ctx_t *ctx =
+        (hm_ctx_t *) ap_get_module_config(cmd->server->module_config,
+                                          &heartmonitor_module);
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+
+    if (err != NULL) {
+        return err;
+    }
+
+    if (!ctx->active) {
+        ctx->active = 1;
+    }
+    else {
+        return "HeartbeatListen: May only be specified once.";
+    }
+
+    rv = apr_parse_addr_port(&host_str, &scope_id, &port, mcast_addr, cmd->temp_pool);
+
+    if (rv) {
+        return "HeartbeatListen: Unable to parse multicast address.";
+    }
+
+    if (host_str == NULL) {
+        return "HeartbeatListen: No host provided in multicast address";
+    }
+
+    if (port == 0) {
+        return "HeartbeatListen: No port provided in multicast address";
+    }
+
+    rv = apr_sockaddr_info_get(&ctx->mcast_addr, host_str, APR_INET, port, 0,
+                               p);
+
+    if (rv) {
+        return
+            "HeartbeatListen: apr_sockaddr_info_get failed on multicast address";
+    }
+
+    return NULL;
+}
+
+static const char *cmd_hm_maxworkers(cmd_parms *cmd,
+                                  void *dconf, const char *data)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+
+    if (err != NULL) {
+        return err;
+    }
+
+    maxworkers = atoi(data);
+    if (maxworkers != 0 && maxworkers < 10)
+        return "HeartbeatMaxServers: Should be 0 for file storage, "
+               "or greater or equal than 10 for slotmem";
+
+    return NULL;
+}
+
+static const command_rec hm_cmds[] = {
+    AP_INIT_TAKE1("HeartbeatListen", cmd_hm_listen, NULL, RSRC_CONF,
+                  "Address to listen for heartbeat requests"),
+    AP_INIT_TAKE1("HeartbeatStorage", cmd_hm_storage, NULL, RSRC_CONF,
+                  "Path to store heartbeat data."),
+    AP_INIT_TAKE1("HeartbeatMaxServers", cmd_hm_maxworkers, NULL, RSRC_CONF,
+                  "Max number of servers when using slotmem (instead file) to store heartbeat data."),
+    {NULL}
+};
+
+AP_DECLARE_MODULE(heartmonitor) = {
+    STANDARD20_MODULE_STUFF,
+    NULL,                       /* create per-directory config structure */
+    NULL,                       /* merge per-directory config structures */
+    hm_create_config,           /* create per-server config structure */
+    NULL,                       /* merge per-server config structures */
+    hm_cmds,                    /* command apr_table_t */
+    hm_register_hooks
+};