zookeeper/src/c/src/zookeeper.c

/**
 * 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.
 */

#ifndef DLL_EXPORT
#  define USE_STATIC_LIB
#endif

#if defined(__CYGWIN__)
#define USE_IPV6
#endif

#include <zookeeper.h>
#include <zookeeper.jute.h>
#include <proto.h>
#include "zk_adaptor.h"
#include "zookeeper_log.h"
#include "zk_hashtable.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <poll.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <stdarg.h>
#include <limits.h>

#include "config.h"

#ifdef HAVE_SYS_UTSNAME_H
#include <sys/utsname.h>
#endif

#ifdef HAVE_GETPWUID_R
#include <pwd.h>
#endif

#define IF_DEBUG(x) if(logLevel==ZOO_LOG_LEVEL_DEBUG) {x;}

const int ZOOKEEPER_WRITE = 1 << 0;
const int ZOOKEEPER_READ = 1 << 1;

const int ZOO_EPHEMERAL = 1 << 0;
const int ZOO_SEQUENCE = 1 << 1;

const int ZOO_EXPIRED_SESSION_STATE = EXPIRED_SESSION_STATE_DEF;
const int ZOO_AUTH_FAILED_STATE = AUTH_FAILED_STATE_DEF;
const int ZOO_CONNECTING_STATE = CONNECTING_STATE_DEF;
const int ZOO_ASSOCIATING_STATE = ASSOCIATING_STATE_DEF;
const int ZOO_CONNECTED_STATE = CONNECTED_STATE_DEF;
static __attribute__ ((unused)) const char* state2String(int state){
    switch(state){
    case 0:
        return "ZOO_CLOSED_STATE";
    case CONNECTING_STATE_DEF:
        return "ZOO_CONNECTING_STATE";
    case ASSOCIATING_STATE_DEF:
        return "ZOO_ASSOCIATING_STATE";
    case CONNECTED_STATE_DEF:
        return "ZOO_CONNECTED_STATE";
    case EXPIRED_SESSION_STATE_DEF:
        return "ZOO_EXPIRED_SESSION_STATE";
    case AUTH_FAILED_STATE_DEF:
        return "ZOO_AUTH_FAILED_STATE";
    }
    return "INVALID_STATE";
}

const int ZOO_CREATED_EVENT = CREATED_EVENT_DEF;
const int ZOO_DELETED_EVENT = DELETED_EVENT_DEF;
const int ZOO_CHANGED_EVENT = CHANGED_EVENT_DEF;
const int ZOO_CHILD_EVENT = CHILD_EVENT_DEF;
const int ZOO_SESSION_EVENT = SESSION_EVENT_DEF;
const int ZOO_NOTWATCHING_EVENT = NOTWATCHING_EVENT_DEF;
static __attribute__ ((unused)) const char* watcherEvent2String(int ev){
    switch(ev){
    case 0:
        return "ZOO_ERROR_EVENT";
    case CREATED_EVENT_DEF:
        return "ZOO_CREATED_EVENT";
    case DELETED_EVENT_DEF:
        return "ZOO_DELETED_EVENT";
    case CHANGED_EVENT_DEF:
        return "ZOO_CHANGED_EVENT";
    case CHILD_EVENT_DEF:
        return "ZOO_CHILD_EVENT";
    case SESSION_EVENT_DEF:
        return "ZOO_SESSION_EVENT";
    case NOTWATCHING_EVENT_DEF:
        return "ZOO_NOTWATCHING_EVENT";
    }
    return "INVALID_EVENT";
}

const int ZOO_PERM_READ = 1 << 0;
const int ZOO_PERM_WRITE = 1 << 1;
const int ZOO_PERM_CREATE = 1 << 2;
const int ZOO_PERM_DELETE = 1 << 3;
const int ZOO_PERM_ADMIN = 1 << 4;
const int ZOO_PERM_ALL = 0x1f;
struct Id ZOO_ANYONE_ID_UNSAFE = {"world", "anyone"};
struct Id ZOO_AUTH_IDS = {"auth", ""};
static struct ACL _OPEN_ACL_UNSAFE_ACL[] = {{0x1f, {"world", "anyone"}}};
static struct ACL _READ_ACL_UNSAFE_ACL[] = {{0x01, {"world", "anyone"}}};
static struct ACL _CREATOR_ALL_ACL_ACL[] = {{0x1f, {"auth", ""}}};
struct ACL_vector ZOO_OPEN_ACL_UNSAFE = { 1, _OPEN_ACL_UNSAFE_ACL};
struct ACL_vector ZOO_READ_ACL_UNSAFE = { 1, _READ_ACL_UNSAFE_ACL};
struct ACL_vector ZOO_CREATOR_ALL_ACL = { 1, _CREATOR_ALL_ACL_ACL};

#define COMPLETION_WATCH -1
#define COMPLETION_VOID 0
#define COMPLETION_STAT 1
#define COMPLETION_DATA 2
#define COMPLETION_STRINGLIST 3
#define COMPLETION_STRINGLIST_STAT 4
#define COMPLETION_ACLLIST 5
#define COMPLETION_STRING 6

typedef struct _auth_completion_list {
    void_completion_t completion;
    const char *auth_data;
    struct _auth_completion_list *next;
} auth_completion_list_t;

typedef struct _completion_list {
    int xid;
    int completion_type; /* one of the COMPLETION_* values */
    union {
        void_completion_t void_result;
        stat_completion_t stat_result;
        data_completion_t data_result;
        strings_completion_t strings_result;
        strings_stat_completion_t strings_stat_result;
        acl_completion_t acl_result;
        string_completion_t string_result;
        struct watcher_object_list *watcher_result;
    } c;
    const void *data;
    buffer_list_t *buffer;
    struct _completion_list *next;
    watcher_registration_t* watcher;
} completion_list_t;

const char*err2string(int err);
static int queue_session_event(zhandle_t *zh, int state);
static const char* format_endpoint_info(const struct sockaddr_storage* ep);
static const char* format_current_endpoint_info(zhandle_t* zh);

/* completion routine forward declarations */
static int add_completion(zhandle_t *zh, int xid, int completion_type,
        const void *dc, const void *data, int add_to_front,watcher_registration_t* wo);
static completion_list_t* create_completion_entry(int xid, int completion_type,
        const void *dc, const void *data,watcher_registration_t* wo);
static void destroy_completion_entry(completion_list_t* c);
static void queue_completion_nolock(completion_head_t *list, completion_list_t *c,
        int add_to_front);
static void queue_completion(completion_head_t *list, completion_list_t *c,
        int add_to_front);
static int handle_socket_error_msg(zhandle_t *zh, int line, int rc,
    const char* format,...);
static void cleanup_bufs(zhandle_t *zh,int callCompletion,int rc);

static int disable_conn_permute=0; // permute enabled by default

static __attribute__((unused)) void print_completion_queue(zhandle_t *zh);

static void *SYNCHRONOUS_MARKER = (void*)&SYNCHRONOUS_MARKER;
static int isValidPath(const char* path, const int flags);

const void *zoo_get_context(zhandle_t *zh)
{
    return zh->context;
}

void zoo_set_context(zhandle_t *zh, void *context)
{
    if (zh != NULL) {
        zh->context = context;
    }
}

int zoo_recv_timeout(zhandle_t *zh)
{
    return zh->recv_timeout;
}

/** these functions are thread unsafe, so make sure that
    zoo_lock_auth is called before you access them **/
static auth_info* get_last_auth(auth_list_head_t *auth_list) {
    auth_info *element;
    element = auth_list->auth;
    if (element == NULL) {
        return NULL;
    }
    while (element->next != NULL) {
        element = element->next;
    }
    return element;
}

static void free_auth_completion(auth_completion_list_t *a_list) {
    auth_completion_list_t *tmp, *ftmp;
    if (a_list == NULL) {
        return;
    }
    tmp = a_list->next;
    while (tmp != NULL) {
        ftmp = tmp;
        tmp = tmp->next;
        ftmp->completion = NULL;
        ftmp->auth_data = NULL;
        free(ftmp);
    }
    a_list->completion = NULL;
    a_list->auth_data = NULL;
    a_list->next = NULL;
    return;
}

static void add_auth_completion(auth_completion_list_t* a_list, void_completion_t* completion,
                                const char *data) {
    auth_completion_list_t *element;
    auth_completion_list_t *n_element;
    element = a_list;
    if (a_list->completion == NULL) {
        //this is the first element
        a_list->completion = *completion;
        a_list->next = NULL;
        a_list->auth_data = data;
        return;
    }
    while (element->next != NULL) {
        element = element->next;
    }
    n_element = (auth_completion_list_t*) malloc(sizeof(auth_completion_list_t));
    n_element->next = NULL;
    n_element->completion = *completion;
    n_element->auth_data = data;
    element->next = n_element;
    return;
}

static void get_auth_completions(auth_list_head_t *auth_list, auth_completion_list_t *a_list) {
    auth_info *element;
    element = auth_list->auth;
    if (element == NULL) {
        return;
    }
    while (element) {
        if (element->completion) {
            add_auth_completion(a_list, &element->completion, element->data);
        }
        element->completion = NULL;
        element = element->next;
    }
    return;
}

static void add_last_auth(auth_list_head_t *auth_list, auth_info *add_el) {
    auth_info  *element;
    element = auth_list->auth;
    if (element == NULL) {
        //first element in the list
        auth_list->auth = add_el;
        return;
    }
    while (element->next != NULL) {
        element = element->next;
    }
    element->next = add_el;
    return;
}

static void init_auth_info(auth_list_head_t *auth_list)
{
    auth_list->auth = NULL;
}

static void mark_active_auth(zhandle_t *zh) {
    auth_list_head_t auth_h = zh->auth_h;
    auth_info *element;
    if (auth_h.auth == NULL) {
        return;
    }
    element = auth_h.auth;
    while (element->next != NULL) {
        element->state = 1;
        element = element->next;
    }
}

static void free_auth_info(auth_list_head_t *auth_list)
{
    auth_info *auth = auth_list->auth;
    while (auth != NULL) {
        auth_info* old_auth = NULL;
        if(auth->scheme!=NULL)
            free(auth->scheme);
        deallocate_Buffer(&auth->auth);
        old_auth = auth;
        auth = auth->next;
        free(old_auth);
    }
    init_auth_info(auth_list);
}

int is_unrecoverable(zhandle_t *zh)
{
    return (zh->state<0)? ZINVALIDSTATE: ZOK;
}

zk_hashtable *exists_result_checker(zhandle_t *zh, int rc)
{
    if (rc == ZOK) {
        return zh->active_node_watchers;
    } else if (rc == ZNONODE) {
        return zh->active_exist_watchers;
    }
    return 0;
}

zk_hashtable *data_result_checker(zhandle_t *zh, int rc)
{
    return rc==ZOK ? zh->active_node_watchers : 0;
}

zk_hashtable *child_result_checker(zhandle_t *zh, int rc)
{
    return rc==ZOK ? zh->active_child_watchers : 0;
}

/**
 * Frees and closes everything associated with a handle,
 * including the handle itself.
 */
static void destroy(zhandle_t *zh)
{
    if (zh == NULL) {
        return;
    }
    /* call any outstanding completions with a special error code */
    cleanup_bufs(zh,1,ZCLOSING);
    if (zh->hostname != 0) {
        free(zh->hostname);
        zh->hostname = NULL;
    }
    if (zh->fd != -1) {
        close(zh->fd);
        zh->fd = -1;
        zh->state = 0;
    }
    if (zh->addrs != 0) {
        free(zh->addrs);
        zh->addrs = NULL;
    }

    if (zh->chroot != 0) {
        free(zh->chroot);
        zh->chroot = NULL;
    }

    free_auth_info(&zh->auth_h);
    destroy_zk_hashtable(zh->active_node_watchers);
    destroy_zk_hashtable(zh->active_exist_watchers);
    destroy_zk_hashtable(zh->active_child_watchers);
}

static void setup_random()
{
    int seed;
    int fd = open("/dev/urandom", O_RDONLY);
    if (fd == -1) {
        seed = getpid();
    } else {
        int rc = read(fd, &seed, sizeof(seed));
        assert(rc == sizeof(seed));
        close(fd);
    }
    srandom(seed);
}

#ifndef __CYGWIN__
/**
 * get the errno from the return code 
 * of get addrinfo. Errno is not set
 * with the call to getaddrinfo, so thats
 * why we have to do this.
 */
static int getaddrinfo_errno(int rc) { 
    switch(rc) {
    case EAI_NONAME:
    case EAI_NODATA:
        return ENOENT;
    case EAI_MEMORY:
        return ENOMEM;
    default:
        return EINVAL;
    }
}
#endif

/**
 * fill in the addrs array of the zookeeper servers in the zhandle. after filling
 * them in, we will permute them for load balancing.
 */
int getaddrs(zhandle_t *zh)
{
    char *hosts = strdup(zh->hostname);
    char *host;
    char *strtok_last;
    struct sockaddr_storage *addr;
    int i;
    int rc;
    int alen = 0; /* the allocated length of the addrs array */

    zh->addrs_count = 0;
    if (zh->addrs) {
        free(zh->addrs);
        zh->addrs = 0;
    }
    if (!hosts) {
         LOG_ERROR(("out of memory"));
        errno=ENOMEM;
        return ZSYSTEMERROR;
    }
    zh->addrs = 0;
    host=strtok_r(hosts, ",", &strtok_last);
    while(host) {
        char *port_spec = strrchr(host, ':');
        char *end_port_spec;
        int port;
        if (!port_spec) {
            LOG_ERROR(("no port in %s", host));
            errno=EINVAL;
            rc=ZBADARGUMENTS;
            goto fail;
        }
        *port_spec = '\0';
        port_spec++;
        port = strtol(port_spec, &end_port_spec, 0);
        if (!*port_spec || *end_port_spec) {
            LOG_ERROR(("invalid port in %s", host));
            errno=EINVAL;
            rc=ZBADARGUMENTS;
            goto fail;
        }
#if defined(__CYGWIN__)
        // sadly CYGWIN doesn't have getaddrinfo
        // but happily gethostbyname is threadsafe in windows
        {
        struct hostent *he;
        char **ptr;
        struct sockaddr_in *addr4;

        he = gethostbyname(host);
        if (!he) {
            LOG_ERROR(("could not resolve %s", host));
            errno=ENOENT;
            rc=ZBADARGUMENTS;
            goto fail;
        }

        /* Setup the address array */
        for(ptr = he->h_addr_list;*ptr != 0; ptr++) {
            if (zh->addrs_count == alen) {
                alen += 16;
                zh->addrs = realloc(zh->addrs, sizeof(*zh->addrs)*alen);
                if (zh->addrs == 0) {
                    LOG_ERROR(("out of memory"));
                    errno=ENOMEM;
                    rc=ZSYSTEMERROR;
                    goto fail;
                }
            }
            addr = &zh->addrs[zh->addrs_count];
            addr4 = (struct sockaddr_in*)addr;
            addr->ss_family = he->h_addrtype;
            if (addr->ss_family == AF_INET) {
                addr4->sin_port = htons(port);
                memset(&addr4->sin_zero, 0, sizeof(addr4->sin_zero));
                memcpy(&addr4->sin_addr, *ptr, he->h_length);
                zh->addrs_count++;
            }
#if defined(AF_INET6)
            else if (addr->ss_family == AF_INET6) {
                struct sockaddr_in6 *addr6;

                addr6 = (struct sockaddr_in6*)addr;
                addr6->sin6_port = htons(port);
                addr6->sin6_scope_id = 0;
                addr6->sin6_flowinfo = 0;
                memcpy(&addr6->sin6_addr, *ptr, he->h_length);
                zh->addrs_count++;
            }
#endif
            else {
                LOG_WARN(("skipping unknown address family %x for %s",
                         addr->ss_family, zh->hostname));
            }
        }
        host = strtok_r(0, ",", &strtok_last);
        }
#else
        {
        struct addrinfo hints, *res, *res0;

        memset(&hints, 0, sizeof(hints));
#ifdef AI_ADDRCONFIG
        hints.ai_flags = AI_ADDRCONFIG;
#else
        hints.ai_flags = 0;
#endif
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;

        while(isspace(*host) && host != strtok_last)
            host++;

        if ((rc = getaddrinfo(host, port_spec, &hints, &res0)) != 0) {
            //bug in getaddrinfo implementation when it returns
            //EAI_BADFLAGS or EAI_ADDRFAMILY with AF_UNSPEC and 
            // ai_flags as AI_ADDRCONFIG
#ifdef AI_ADDRCONFIG
            if ((hints.ai_flags == AI_ADDRCONFIG) && 
                ((rc ==EAI_BADFLAGS) || (rc == EAI_ADDRFAMILY))) {
                //reset ai_flags to null
                hints.ai_flags = 0;
                //retry getaddrinfo
                rc = getaddrinfo(host, port_spec, &hints, &res0);
            }
#endif
            if (rc != 0) {
                errno = getaddrinfo_errno(rc);
                LOG_ERROR(("getaddrinfo: %s\n", strerror(errno)));
                rc=ZSYSTEMERROR;
                goto fail;
            }
        }

        for (res = res0; res; res = res->ai_next) {
            // Expand address list if needed
            if (zh->addrs_count == alen) {
                void *tmpaddr;
                alen += 16;
                tmpaddr = realloc(zh->addrs, sizeof(*zh->addrs)*alen);
                if (tmpaddr == 0) {
                    LOG_ERROR(("out of memory"));
                    errno=ENOMEM;
                    rc=ZSYSTEMERROR;
                    goto fail;
                }
                zh->addrs=tmpaddr;
            }

            // Copy addrinfo into address list
            addr = &zh->addrs[zh->addrs_count];
            switch (res->ai_family) {
            case AF_INET:
#if defined(AF_INET6)
            case AF_INET6:
#endif
                memcpy(addr, res->ai_addr, res->ai_addrlen);
                ++zh->addrs_count;
                break;
            default:
                LOG_WARN(("skipping unknown address family %x for %s",
                res->ai_family, zh->hostname));
                break;
            }
        }

        freeaddrinfo(res0);

        host = strtok_r(0, ",", &strtok_last);
        }
#endif
    }
    free(hosts);

    if(!disable_conn_permute){
        setup_random();
        /* Permute */
        for(i = 0; i < zh->addrs_count; i++) {
            struct sockaddr_storage *s1 = zh->addrs + random()%zh->addrs_count;
            struct sockaddr_storage *s2 = zh->addrs + random()%zh->addrs_count;
            if (s1 != s2) {
                struct sockaddr_storage t = *s1;
                *s1 = *s2;
                *s2 = t;
            }
        }
    }
    return ZOK;
fail:
    if (zh->addrs) {
        free(zh->addrs);
        zh->addrs=0;
    }
    if (hosts) {
        free(hosts);
    }
    return rc;
}

const clientid_t *zoo_client_id(zhandle_t *zh)
{
    return &zh->client_id;
}

static void null_watcher_fn(zhandle_t* p1, int p2, int p3,const char* p4,void*p5){}

watcher_fn zoo_set_watcher(zhandle_t *zh,watcher_fn newFn)
{
    watcher_fn oldWatcher=zh->watcher;
    if (newFn) {
       zh->watcher = newFn;
    } else {
       zh->watcher = null_watcher_fn;
    }
    return oldWatcher;
}

static void log_env() {
  char buf[2048];
#ifdef HAVE_SYS_UTSNAME_H
  struct utsname utsname;
#endif

#if defined(HAVE_GETUID) && defined(HAVE_GETPWUID_R)
  struct passwd pw;
  struct passwd *pwp = NULL;
  uid_t uid = 0;
#endif

  LOG_INFO(("Client environment:zookeeper.version=%s", PACKAGE_STRING));

#ifdef HAVE_GETHOSTNAME
  gethostname(buf, sizeof(buf));
  LOG_INFO(("Client environment:host.name=%s", buf));
#else
  LOG_INFO(("Client environment:host.name=<not implemented>"));
#endif

#ifdef HAVE_SYS_UTSNAME_H
  uname(&utsname);
  LOG_INFO(("Client environment:os.name=%s", utsname.sysname));
  LOG_INFO(("Client environment:os.arch=%s", utsname.release));
  LOG_INFO(("Client environment:os.version=%s", utsname.version));
#else
  LOG_INFO(("Client environment:os.name=<not implemented>"));
  LOG_INFO(("Client environment:os.arch=<not implemented>"));
  LOG_INFO(("Client environment:os.version=<not implemented>"));
#endif

#ifdef HAVE_GETLOGIN
  LOG_INFO(("Client environment:user.name=%s", getlogin()));
#else
  LOG_INFO(("Client environment:user.name=<not implemented>"));
#endif

#if defined(HAVE_GETUID) && defined(HAVE_GETPWUID_R)
  uid = getuid();
  if (!getpwuid_r(uid, &pw, buf, sizeof(buf), &pwp)) {
    LOG_INFO(("Client environment:user.home=%s", pw.pw_dir));
  } else {
    LOG_INFO(("Client environment:user.home=<NA>"));
  }
#else
  LOG_INFO(("Client environment:user.home=<not implemented>"));
#endif

#ifdef HAVE_GETCWD
  if (!getcwd(buf, sizeof(buf))) {
    LOG_INFO(("Client environment:user.dir=<toolong>"));
  } else {
    LOG_INFO(("Client environment:user.dir=%s", buf));
  }
#else
  LOG_INFO(("Client environment:user.dir=<not implemented>"));
#endif
}

/**
 * Create a zookeeper handle associated with the given host and port.
 */
zhandle_t *zookeeper_init(const char *host, watcher_fn watcher,
  int recv_timeout, const clientid_t *clientid, void *context, int flags)
{
    int errnosave = 0;
    zhandle_t *zh = NULL;
    char *index_chroot = NULL;

    log_env();

    LOG_INFO(("Initiating client connection, host=%s sessionTimeout=%d watcher=%p"
          " sessionId=%#llx sessionPasswd=%s context=%p flags=%d",
              host,
              recv_timeout,
              watcher,
              (clientid == 0 ? 0 : clientid->client_id),
              ((clientid == 0) || (clientid->passwd == 0) ?
               "<null>" : "<hidden>"),
              context,
              flags));

    zh = calloc(1, sizeof(*zh));
    if (!zh) {
        return 0;
    }
    zh->fd = -1;
    zh->state = 0;
    zh->context = context;
    zh->recv_timeout = recv_timeout;
    init_auth_info(&zh->auth_h);
    if (watcher) {
       zh->watcher = watcher;
    } else {
       zh->watcher = null_watcher_fn;
    }
    if (host == 0 || *host == 0) { // what we shouldn't dup
        errno=EINVAL;
        goto abort;
    }
    //parse the host to get the chroot if
    //available
    index_chroot = strchr(host, '/');
    if (index_chroot) {
        zh->chroot = strdup(index_chroot);
        // if chroot is just / set it to null
        if (strlen(zh->chroot) == 1) {
            zh->chroot = NULL;
        }
        // cannot use strndup so allocate and strcpy
        zh->hostname = (char *) malloc(index_chroot - host + 1);
        zh->hostname = strncpy(zh->hostname, host, (index_chroot - host));
        //strncpy does not null terminate
        *(zh->hostname + (index_chroot - host)) = '\0';

    } else {
        zh->chroot = NULL;
        zh->hostname = strdup(host);
    }
    if (zh->chroot && !isValidPath(zh->chroot, 0)) {
        errno = EINVAL;
        goto abort;
    }
    if (zh->hostname == 0) {
        goto abort;
    }
    if(getaddrs(zh)!=0) {
        goto abort;
    }
    zh->connect_index = 0;
    if (clientid) {
        memcpy(&zh->client_id, clientid, sizeof(zh->client_id));
    } else {
        memset(&zh->client_id, 0, sizeof(zh->client_id));
    }
    zh->primer_buffer.buffer = zh->primer_storage_buffer;
    zh->primer_buffer.curr_offset = 0;
    zh->primer_buffer.len = sizeof(zh->primer_storage_buffer);
    zh->primer_buffer.next = 0;
    zh->last_zxid = 0;
    zh->next_deadline.tv_sec=zh->next_deadline.tv_usec=0;
    zh->socket_readable.tv_sec=zh->socket_readable.tv_usec=0;
    zh->active_node_watchers=create_zk_hashtable();
    zh->active_exist_watchers=create_zk_hashtable();
    zh->active_child_watchers=create_zk_hashtable();

    if (adaptor_init(zh) == -1) {
        goto abort;
    }

    return zh;
abort:
    errnosave=errno;
    destroy(zh);
    free(zh);
    errno=errnosave;
    return 0;
}

/**
 * deallocated the free_path only its beeen allocated
 * and not equal to path
 */
void free_duplicate_path(const char *free_path, const char* path) {
    if (free_path != path) {
        free((void*)free_path);
    }
}

/**
  prepend the chroot path if available else return the path
*/
static char* prepend_string(zhandle_t *zh, const char* client_path) {
    char *ret_str;
    if (zh->chroot == NULL)
        return (char *) client_path;
    // handle the chroot itself, client_path = "/"
    if (strlen(client_path) == 1) {
        return strdup(zh->chroot);
    }
    ret_str = (char *) malloc(strlen(zh->chroot) + strlen(client_path) + 1);
    strcpy(ret_str, zh->chroot);
    return strcat(ret_str, client_path);
}

/**
   strip off the chroot string from the server path
   if there is one else return the exact path
 */
char* sub_string(zhandle_t *zh, const char* server_path) {
    char *ret_str;
    if (zh->chroot == NULL)
        return (char *) server_path;
    if (strncmp(server_path, zh->chroot, strlen(zh->chroot) != 0)) {
        LOG_ERROR(("server path %s does not include chroot path %s",
                   server_path, zh->chroot));
        return NULL;
    }
    if (strlen(server_path) == strlen(zh->chroot)) {
        //return "/"
        ret_str = strdup("/");
        return ret_str;
    }
    ret_str = strdup(server_path + strlen(zh->chroot));
    return ret_str;
}

static buffer_list_t *allocate_buffer(char *buff, int len)
{
    buffer_list_t *buffer = calloc(1, sizeof(*buffer));
    if (buffer == 0)
        return 0;

    buffer->len = len==0?sizeof(*buffer):len;
    buffer->curr_offset = 0;
    buffer->buffer = buff;
    buffer->next = 0;
    return buffer;
}

static void free_buffer(buffer_list_t *b)
{
    if (!b) {
        return;
    }
    if (b->buffer) {
        free(b->buffer);
    }
    free(b);
}

static buffer_list_t *dequeue_buffer(buffer_head_t *list)
{
    buffer_list_t *b;
    lock_buffer_list(list);
    b = list->head;
    if (b) {
        list->head = b->next;
        if (!list->head) {
            assert(b == list->last);
            list->last = 0;
        }
    }
    unlock_buffer_list(list);
    return b;
}

static int remove_buffer(buffer_head_t *list)
{
    buffer_list_t *b = dequeue_buffer(list);
    if (!b) {
        return 0;
    }
    free_buffer(b);
    return 1;
}

static void queue_buffer(buffer_head_t *list, buffer_list_t *b, int add_to_front)
{
    b->next = 0;
    lock_buffer_list(list);
    if (list->head) {
        assert(list->last);
        // The list is not empty
        if (add_to_front) {
            b->next = list->head;
            list->head = b;
        } else {
            list->last->next = b;
            list->last = b;
        }
    }else{
        // The list is empty
        assert(!list->head);
        list->head = b;
        list->last = b;
    }
    unlock_buffer_list(list);
}

static int queue_buffer_bytes(buffer_head_t *list, char *buff, int len)
{
    buffer_list_t *b  = allocate_buffer(buff,len);
    if (!b)
        return ZSYSTEMERROR;
    queue_buffer(list, b, 0);
    return ZOK;
}

static int queue_front_buffer_bytes(buffer_head_t *list, char *buff, int len)
{
    buffer_list_t *b  = allocate_buffer(buff,len);
    if (!b)
        return ZSYSTEMERROR;
    queue_buffer(list, b, 1);
    return ZOK;
}

static __attribute__ ((unused)) int get_queue_len(buffer_head_t *list)
{
    int i;
    buffer_list_t *ptr;
    lock_buffer_list(list);
    ptr = list->head;
    for (i=0; ptr!=0; ptr=ptr->next, i++)
        ;
    unlock_buffer_list(list);
    return i;
}
/* returns:
 * -1 if send failed,
 * 0 if send would block while sending the buffer (or a send was incomplete),
 * 1 if success
 */
static int send_buffer(int fd, buffer_list_t *buff)
{
    int len = buff->len;
    int off = buff->curr_offset;
    int rc = -1;

    if (off < 4) {
        /* we need to send the length at the beginning */
        int nlen = htonl(len);
        char *b = (char*)&nlen;
        rc = send(fd, b + off, sizeof(nlen) - off, 0);
        if (rc == -1) {
            if (errno != EAGAIN) {
                return -1;
            } else {
                return 0;
            }
        } else {
            buff->curr_offset  += rc;
        }
        off = buff->curr_offset;
    }
    if (off >= 4) {
        /* want off to now represent the offset into the buffer */
        off -= sizeof(buff->len);
        rc = send(fd, buff->buffer + off, len - off, 0);
        if (rc == -1) {
            if (errno != EAGAIN) {
                return -1;
            }
        } else {
            buff->curr_offset += rc;
        }
    }
    return buff->curr_offset == len + sizeof(buff->len);
}

/* returns:
 * -1 if recv call failed,
 * 0 if recv would block,
 * 1 if success
 */
static int recv_buffer(int fd, buffer_list_t *buff)
{
    int off = buff->curr_offset;
    int rc = 0;
    //fprintf(LOGSTREAM, "rc = %d, off = %d, line %d\n", rc, off, __LINE__);

    /* if buffer is less than 4, we are reading in the length */
    if (off < 4) {
        char *buffer = (char*)&(buff->len);
        rc = recv(fd, buffer+off, sizeof(int)-off, 0);
        //fprintf(LOGSTREAM, "rc = %d, off = %d, line %d\n", rc, off, __LINE__);
        switch(rc) {
        case 0:
            errno = EHOSTDOWN;
        case -1:
            if (errno == EAGAIN) {
                return 0;
            }
            return -1;
        default:
            buff->curr_offset += rc;
        }
        off = buff->curr_offset;
        if (buff->curr_offset == sizeof(buff->len)) {
            buff->len = ntohl(buff->len);
            buff->buffer = calloc(1, buff->len);
        }
    }
    if (buff->buffer) {
        /* want off to now represent the offset into the buffer */
        off -= sizeof(buff->len);

        rc = recv(fd, buff->buffer+off, buff->len-off, 0);
        switch(rc) {
        case 0:
            errno = EHOSTDOWN;
        case -1:
            if (errno == EAGAIN) {
                break;
            }
            return -1;
        default:
            buff->curr_offset += rc;
        }
    }
    return buff->curr_offset == buff->len + sizeof(buff->len);
}

void free_buffers(buffer_head_t *list)
{
    while (remove_buffer(list))
        ;
}

void free_completions(zhandle_t *zh,int callCompletion,int reason)
{
    completion_head_t tmp_list;
    struct oarchive *oa;
    struct ReplyHeader h;
    void_completion_t auth_completion = NULL;
    auth_completion_list_t a_list, *a_tmp;

    lock_completion_list(&zh->sent_requests);
    tmp_list = zh->sent_requests;
    zh->sent_requests.head = 0;
    zh->sent_requests.last = 0;
    unlock_completion_list(&zh->sent_requests);
    while (tmp_list.head) {
        completion_list_t *cptr = tmp_list.head;

        tmp_list.head = cptr->next;
        if (cptr->c.data_result == SYNCHRONOUS_MARKER) {
            struct sync_completion
                        *sc = (struct sync_completion*)cptr->data;
            sc->rc = reason;
            notify_sync_completion(sc);
            zh->outstanding_sync--;
            destroy_completion_entry(cptr);
        } else if (callCompletion) {
            if(cptr->xid == PING_XID){
                // Nothing to do with a ping response
                destroy_completion_entry(cptr);
            } else {
                // Fake the response
                buffer_list_t *bptr;
                h.xid = cptr->xid;
                h.zxid = -1;
                h.err = reason;
                oa = create_buffer_oarchive();
                serialize_ReplyHeader(oa, "header", &h);
                bptr = calloc(sizeof(*bptr), 1);
                assert(bptr);
                bptr->len = get_buffer_len(oa);
                bptr->buffer = get_buffer(oa);
                close_buffer_oarchive(&oa, 0);
                cptr->buffer = bptr;
                queue_completion(&zh->completions_to_process, cptr, 0);
            }
        }
    }
    a_list.completion = NULL;
    a_list.next = NULL;
    zoo_lock_auth(zh);
    get_auth_completions(&zh->auth_h, &a_list);
    zoo_unlock_auth(zh);
    a_tmp = &a_list;
    // chain call user's completion function
    while (a_tmp->completion != NULL) {
        auth_completion = a_tmp->completion;
        auth_completion(reason, a_tmp->auth_data);
        a_tmp = a_tmp->next;
        if (a_tmp == NULL)
            break;
    }
    free_auth_completion(&a_list);
}

static void cleanup_bufs(zhandle_t *zh,int callCompletion,int rc)
{
    enter_critical(zh);
    free_buffers(&zh->to_send);
    free_buffers(&zh->to_process);
    free_completions(zh,callCompletion,rc);
    leave_critical(zh);
    if (zh->input_buffer && zh->input_buffer != &zh->primer_buffer) {
        free_buffer(zh->input_buffer);
        zh->input_buffer = 0;
    }
}

static void handle_error(zhandle_t *zh,int rc)
{
    close(zh->fd);
    if (is_unrecoverable(zh)) {
        LOG_DEBUG(("Calling a watcher for a ZOO_SESSION_EVENT and the state=%s",
                state2String(zh->state)));
        PROCESS_SESSION_EVENT(zh, zh->state);
    } else if (zh->state == ZOO_CONNECTED_STATE) {
        LOG_DEBUG(("Calling a watcher for a ZOO_SESSION_EVENT and the state=CONNECTING_STATE"));
        PROCESS_SESSION_EVENT(zh, ZOO_CONNECTING_STATE);
    }
    cleanup_bufs(zh,1,rc);
    zh->fd = -1;
    zh->connect_index++;
    if (!is_unrecoverable(zh)) {
        zh->state = 0;
    }
    if (process_async(zh->outstanding_sync)) {
        process_completions(zh);
    }
}

static int handle_socket_error_msg(zhandle_t *zh, int line, int rc,
        const char* format, ...)
{
    if(logLevel>=ZOO_LOG_LEVEL_ERROR){
        va_list va;
        char buf[1024];
        va_start(va,format);
        vsnprintf(buf, sizeof(buf)-1,format,va);
        log_message(ZOO_LOG_LEVEL_ERROR,line,__func__,
            format_log_message("Socket [%s] zk retcode=%d, errno=%d(%s): %s",
            format_current_endpoint_info(zh),rc,errno,strerror(errno),buf));
        va_end(va);
    }
    handle_error(zh,rc);
    return rc;
}

static void auth_completion_func(int rc, zhandle_t* zh)
{
    void_completion_t auth_completion = NULL;
    auth_completion_list_t a_list;
    auth_completion_list_t *a_tmp;

    if(zh==NULL)
        return;

    zoo_lock_auth(zh);

    if(rc!=0){
        zh->state=ZOO_AUTH_FAILED_STATE;
    }else{
        //change state for all auths
        mark_active_auth(zh);
    }
    a_list.completion = NULL;
    a_list.next = NULL;
    get_auth_completions(&zh->auth_h, &a_list);
    zoo_unlock_auth(zh);
    if (rc) {
        LOG_ERROR(("Authentication scheme %s failed. Connection closed.",
                   zh->auth_h.auth->scheme));
    }
    else {
        LOG_INFO(("Authentication scheme %s succeeded", zh->auth_h.auth->scheme));
    }
    a_tmp = &a_list;
    // chain call user's completion function
    while (a_tmp->completion != NULL) {
        auth_completion = a_tmp->completion;
        auth_completion(rc, a_tmp->auth_data);
        a_tmp = a_tmp->next;
        if (a_tmp == NULL)
            break;
    }
    free_auth_completion(&a_list);
}

static int send_info_packet(zhandle_t *zh, auth_info* auth) {
    struct oarchive *oa;
    struct RequestHeader h = { .xid = AUTH_XID, .type = SETAUTH_OP};
    struct AuthPacket req;
    int rc;
    oa = create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    req.type=0;   // ignored by the server
    req.scheme = auth->scheme;
    req.auth = auth->auth;
    rc = rc < 0 ? rc : serialize_AuthPacket(oa, "req", &req);
    /* add this buffer to the head of the send queue */
    rc = rc < 0 ? rc : queue_front_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    return rc;
}

/** send all auths, not just the last one **/
static int send_auth_info(zhandle_t *zh) {
    int rc = 0;
    auth_info *auth = NULL;

    zoo_lock_auth(zh);
    auth = zh->auth_h.auth;
    if (auth == NULL) {
        zoo_unlock_auth(zh);
        return ZOK;
    }
    while (auth->next != NULL) {
        rc = send_info_packet(zh, auth);
        auth = auth->next;
    }
    zoo_unlock_auth(zh);
    LOG_DEBUG(("Sending all auth info request to %s", format_current_endpoint_info(zh)));
    return (rc <0) ? ZMARSHALLINGERROR:ZOK;
}

static int send_last_auth_info(zhandle_t *zh)
{    
    int rc = 0;
    auth_info *auth = NULL;

    zoo_lock_auth(zh);
    auth = get_last_auth(&zh->auth_h);
    if(auth==NULL) {
      zoo_unlock_auth(zh);
      return ZOK; // there is nothing to send
    }
    rc = send_info_packet(zh, auth);
    zoo_unlock_auth(zh);
    LOG_DEBUG(("Sending auth info request to %s",format_current_endpoint_info(zh)));
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

static void free_key_list(char **list, int count)
{
    int i;

    for(i = 0; i < count; i++) {
        free(list[i]);
    }
    free(list);
}

static int send_set_watches(zhandle_t *zh)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = SET_WATCHES_XID, .type = SETWATCHES_OP};
    struct SetWatches req;
    int rc;

    req.relativeZxid = zh->last_zxid;
    req.dataWatches.data = collect_keys(zh->active_node_watchers, (int*)&req.dataWatches.count);
    req.existWatches.data = collect_keys(zh->active_exist_watchers, (int*)&req.existWatches.count);
    req.childWatches.data = collect_keys(zh->active_child_watchers, (int*)&req.childWatches.count);

    // return if there are no pending watches
    if (!req.dataWatches.count && !req.existWatches.count &&
        !req.childWatches.count) {
        free_key_list(req.dataWatches.data, req.dataWatches.count);
        free_key_list(req.existWatches.data, req.existWatches.count);
        free_key_list(req.childWatches.data, req.childWatches.count);
        return ZOK;
    }


    oa = create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_SetWatches(oa, "req", &req);
    /* add this buffer to the head of the send queue */
    rc = rc < 0 ? rc : queue_front_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    /* We queued the buffer, so don't free it */   
    close_buffer_oarchive(&oa, 0);
    free_key_list(req.dataWatches.data, req.dataWatches.count);
    free_key_list(req.existWatches.data, req.existWatches.count);
    free_key_list(req.childWatches.data, req.childWatches.count);
    LOG_DEBUG(("Sending set watches request to %s",format_current_endpoint_info(zh)));
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

static int serialize_prime_connect(struct connect_req *req, char* buffer){
    //this should be the order of serialization
    int offset = 0;
    req->protocolVersion = htonl(req->protocolVersion);
    memcpy(buffer + offset, &req->protocolVersion, sizeof(req->protocolVersion));
    offset = offset +  sizeof(req->protocolVersion);

    req->lastZxidSeen = htonll(req->lastZxidSeen);
    memcpy(buffer + offset, &req->lastZxidSeen, sizeof(req->lastZxidSeen));
    offset = offset +  sizeof(req->lastZxidSeen);

    req->timeOut = htonl(req->timeOut);
    memcpy(buffer + offset, &req->timeOut, sizeof(req->timeOut));
    offset = offset +  sizeof(req->timeOut);

    req->sessionId = htonll(req->sessionId);
    memcpy(buffer + offset, &req->sessionId, sizeof(req->sessionId));
    offset = offset +  sizeof(req->sessionId);

    req->passwd_len = htonl(req->passwd_len);
    memcpy(buffer + offset, &req->passwd_len, sizeof(req->passwd_len));
    offset = offset +  sizeof(req->passwd_len);

    memcpy(buffer + offset, req->passwd, sizeof(req->passwd));

    return 0;
}

 static int deserialize_prime_response(struct prime_struct *req, char* buffer){
     //this should be the order of deserialization
     int offset = 0;
     memcpy(&req->len, buffer + offset, sizeof(req->len));
     offset = offset +  sizeof(req->len);

     req->len = ntohl(req->len);
     memcpy(&req->protocolVersion, buffer + offset, sizeof(req->protocolVersion));
     offset = offset +  sizeof(req->protocolVersion);

     req->protocolVersion = ntohl(req->protocolVersion);
     memcpy(&req->timeOut, buffer + offset, sizeof(req->timeOut));
     offset = offset +  sizeof(req->timeOut);

     req->timeOut = ntohl(req->timeOut);
     memcpy(&req->sessionId, buffer + offset, sizeof(req->sessionId));
     offset = offset +  sizeof(req->sessionId);

     req->sessionId = htonll(req->sessionId);
     memcpy(&req->passwd_len, buffer + offset, sizeof(req->passwd_len));
     offset = offset +  sizeof(req->passwd_len);

     req->passwd_len = ntohl(req->passwd_len);
     memcpy(req->passwd, buffer + offset, sizeof(req->passwd));
     return 0;
 }

static int prime_connection(zhandle_t *zh)
{
    int rc;
    /*this is the size of buffer to serialize req into*/
    char buffer_req[HANDSHAKE_REQ_SIZE];
    int len = sizeof(buffer_req);
    int hlen = 0;
    struct connect_req req;
    req.protocolVersion = 0;
    req.sessionId = zh->client_id.client_id;
    req.passwd_len = sizeof(req.passwd);
    memcpy(req.passwd, zh->client_id.passwd, sizeof(zh->client_id.passwd));
    req.timeOut = zh->recv_timeout;
    req.lastZxidSeen = zh->last_zxid;
    hlen = htonl(len);
    /* We are running fast and loose here, but this string should fit in the initial buffer! */
    rc=send(zh->fd, &hlen, sizeof(len), 0);
    serialize_prime_connect(&req, buffer_req);
    rc=rc<0 ? rc : send(zh->fd, buffer_req, len, 0);
    if (rc<0) {
        return handle_socket_error_msg(zh, __LINE__, ZCONNECTIONLOSS,
                "failed to send a handshake packet: %s", strerror(errno));
    }
    zh->state = ZOO_ASSOCIATING_STATE;

    zh->input_buffer = &zh->primer_buffer;
    /* This seems a bit weird to to set the offset to 4, but we already have a
     * length, so we skip reading the length (and allocating the buffer) by
     * saying that we are already at offset 4 */
    zh->input_buffer->curr_offset = 4;

    return ZOK;
}

static inline int calculate_interval(const struct timeval *start,
        const struct timeval *end)
{
    int interval;
    struct timeval i = *end;
    i.tv_sec -= start->tv_sec;
    i.tv_usec -= start->tv_usec;
    interval = i.tv_sec * 1000 + (i.tv_usec/1000);
    return interval;
}

static struct timeval get_timeval(int interval)
{
    struct timeval tv;
    if (interval < 0) {
        interval = 0;
    }
    tv.tv_sec = interval/1000;
    tv.tv_usec = (interval%1000)*1000;
    return tv;
}

 static int add_void_completion(zhandle_t *zh, int xid, void_completion_t dc,
     const void *data);
 static int add_string_completion(zhandle_t *zh, int xid,
     string_completion_t dc, const void *data);

 int send_ping(zhandle_t* zh)
 {
    int rc;
    struct oarchive *oa = create_buffer_oarchive();
    struct RequestHeader h = { .xid = PING_XID, .type = PING_OP };

    rc = serialize_RequestHeader(oa, "header", &h);
    enter_critical(zh);
    gettimeofday(&zh->last_ping, 0);
    rc = rc < 0 ? rc : add_void_completion(zh, h.xid, 0, 0);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    close_buffer_oarchive(&oa, 0);
    return rc<0 ? rc : adaptor_send_queue(zh, 0);
}

 int zookeeper_interest(zhandle_t *zh, int *fd, int *interest,
     struct timeval *tv)
{
    struct timeval now;
    if(zh==0 || fd==0 ||interest==0 || tv==0)
        return ZBADARGUMENTS;
    if (is_unrecoverable(zh))
        return ZINVALIDSTATE;
    gettimeofday(&now, 0);
    if(zh->next_deadline.tv_sec!=0 || zh->next_deadline.tv_usec!=0){
        int time_left = calculate_interval(&zh->next_deadline, &now);
        if (time_left > 10)
            LOG_WARN(("Exceeded deadline by %dms", time_left));
    }
    api_prolog(zh);
    *fd = zh->fd;
    *interest = 0;
    tv->tv_sec = 0;
    tv->tv_usec = 0;
    if (*fd == -1) {
        if (zh->connect_index == zh->addrs_count) {
            /* Wait a bit before trying again so that we don't spin */
            zh->connect_index = 0;
        }else {
            int rc;
            int on = 1;

            zh->fd = socket(zh->addrs[zh->connect_index].ss_family, SOCK_STREAM, 0);
            if (zh->fd < 0) {
                return api_epilog(zh,handle_socket_error_msg(zh,__LINE__,
                                                             ZSYSTEMERROR, "socket() call failed"));
            }
            setsockopt(zh->fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(int));
            fcntl(zh->fd, F_SETFL, O_NONBLOCK|fcntl(zh->fd, F_GETFL, 0));
#if defined(AF_INET6)
            if (zh->addrs[zh->connect_index].ss_family == AF_INET6) {
                rc = connect(zh->fd, (struct sockaddr*) &zh->addrs[zh->connect_index], sizeof(struct sockaddr_in6));
            } else {
#else
            {
#endif
                rc = connect(zh->fd, (struct sockaddr*) &zh->addrs[zh->connect_index], sizeof(struct sockaddr_in));
            }
            if (rc == -1) {
                /* we are handling the non-blocking connect according to
                 * the description in section 16.3 "Non-blocking connect"
                 * in UNIX Network Programming vol 1, 3rd edition */
                if (errno == EWOULDBLOCK || errno == EINPROGRESS)
                    zh->state = ZOO_CONNECTING_STATE;
                else
                    return api_epilog(zh,handle_socket_error_msg(zh,__LINE__,
                            ZCONNECTIONLOSS,"connect() call failed"));
            } else {
                if((rc=prime_connection(zh))!=0)
                    return api_epilog(zh,rc);

                LOG_INFO(("Initiated connection to server [%s]",
                        format_endpoint_info(&zh->addrs[zh->connect_index])));
            }
        }
        *fd = zh->fd;
        *tv = get_timeval(zh->recv_timeout/3);
        zh->last_recv = now;
        zh->last_send = now;
        zh->last_ping = now;
    }
    if (zh->fd != -1) {
        int idle_recv = calculate_interval(&zh->last_recv, &now);
        int idle_send = calculate_interval(&zh->last_send, &now);
        int recv_to = zh->recv_timeout*2/3 - idle_recv;
        int send_to = zh->recv_timeout/3;
        // have we exceeded the receive timeout threshold?
        if (recv_to <= 0) {
            // We gotta cut our losses and connect to someone else
            errno = ETIMEDOUT;
            *fd=-1;
            *interest=0;
            *tv = get_timeval(0);
            return api_epilog(zh,handle_socket_error_msg(zh,
                    __LINE__,ZOPERATIONTIMEOUT,
                    "connection timed out (exceeded timeout by %dms)",-recv_to));
        }
        // We only allow 1/3 of our timeout time to expire before sending
        // a PING
        if (zh->state==ZOO_CONNECTED_STATE) {
            send_to = zh->recv_timeout/3 - idle_send;
            if (send_to <= 0 && zh->sent_requests.head==0) {
//                LOG_DEBUG(("Sending PING to %s (exceeded idle by %dms)",
//                                format_current_endpoint_info(zh),-send_to));
                int rc=send_ping(zh);
                if (rc < 0){
                    LOG_ERROR(("failed to send PING request (zk retcode=%d)",rc));
                    return api_epilog(zh,rc);
                }
                send_to = zh->recv_timeout/3;
            }
        }
        // choose the lesser value as the timeout
        *tv = get_timeval(recv_to < send_to? recv_to:send_to);
        zh->next_deadline.tv_sec = now.tv_sec + tv->tv_sec;
        zh->next_deadline.tv_usec = now.tv_usec + tv->tv_usec;
        if (zh->next_deadline.tv_usec > 1000000) {
            zh->next_deadline.tv_sec += zh->next_deadline.tv_usec / 1000000;
            zh->next_deadline.tv_usec = zh->next_deadline.tv_usec % 1000000;
        }
        *interest = ZOOKEEPER_READ;
        /* we are interested in a write if we are connected and have something
         * to send, or we are waiting for a connect to finish. */
        if ((zh->to_send.head && (zh->state == ZOO_CONNECTED_STATE))
        || zh->state == ZOO_CONNECTING_STATE) {
            *interest |= ZOOKEEPER_WRITE;
        }
    }
    return api_epilog(zh,ZOK);
}

static int check_events(zhandle_t *zh, int events)
{
    if (zh->fd == -1)
        return ZINVALIDSTATE;
    if ((events&ZOOKEEPER_WRITE)&&(zh->state == ZOO_CONNECTING_STATE)) {
        int rc, error;
        socklen_t len = sizeof(error);
        rc = getsockopt(zh->fd, SOL_SOCKET, SO_ERROR, &error, &len);
        /* the description in section 16.4 "Non-blocking connect"
         * in UNIX Network Programming vol 1, 3rd edition, points out
         * that sometimes the error is in errno and sometimes in error */
        if (rc < 0 || error) {
            if (rc == 0)
                errno = error;
            return handle_socket_error_msg(zh, __LINE__,ZCONNECTIONLOSS,
                "server refused to accept the client");
        }
        if((rc=prime_connection(zh))!=0)
            return rc;
        LOG_INFO(("initiated connection to server [%s]",
                format_endpoint_info(&zh->addrs[zh->connect_index])));
        return ZOK;
    }
    if (zh->to_send.head && (events&ZOOKEEPER_WRITE)) {
        /* make the flush call non-blocking by specifying a 0 timeout */
        int rc=flush_send_queue(zh,0);
        if (rc < 0)
            return handle_socket_error_msg(zh,__LINE__,ZCONNECTIONLOSS,
                "failed while flushing send queue");
    }
    if (events&ZOOKEEPER_READ) {
        int rc;
        if (zh->input_buffer == 0) {
            zh->input_buffer = allocate_buffer(0,0);
        }

        rc = recv_buffer(zh->fd, zh->input_buffer);
        if (rc < 0) {
            return handle_socket_error_msg(zh, __LINE__,ZCONNECTIONLOSS,
                "failed while receiving a server response");
        }
        if (rc > 0) {
            gettimeofday(&zh->last_recv, 0);
            if (zh->input_buffer != &zh->primer_buffer) {
                queue_buffer(&zh->to_process, zh->input_buffer, 0);
            } else  {
                int64_t oldid,newid;
                //deserialize
                deserialize_prime_response(&zh->primer_storage, zh->primer_buffer.buffer);
                /* We are processing the primer_buffer, so we need to finish
                 * the connection handshake */
                oldid = zh->client_id.client_id;
                newid = zh->primer_storage.sessionId;
                if (oldid != 0 && oldid != newid) {
                    zh->state = ZOO_EXPIRED_SESSION_STATE;
                    errno = ESTALE;
                    return handle_socket_error_msg(zh,__LINE__,ZSESSIONEXPIRED,
                            "sessionId=%#llx has expired.",oldid);
                } else {
                    zh->recv_timeout = zh->primer_storage.timeOut;
                    zh->client_id.client_id = newid;
                 
                    memcpy(zh->client_id.passwd, &zh->primer_storage.passwd,
                           sizeof(zh->client_id.passwd));
                    zh->state = ZOO_CONNECTED_STATE;
                    LOG_INFO(("session establishment complete on server [%s], sessionId=%#llx, negotiated timeout=%d",
                              format_endpoint_info(&zh->addrs[zh->connect_index]),
                              newid, zh->recv_timeout));
                    /* we want the auth to be sent for, but since both call push to front
                       we need to call send_watch_set first */
                    send_set_watches(zh);
                    /* send the authentication packet now */
                    send_auth_info(zh);
                    LOG_DEBUG(("Calling a watcher for a ZOO_SESSION_EVENT and the state=ZOO_CONNECTED_STATE"));
                    zh->input_buffer = 0; // just in case the watcher calls zookeeper_process() again
                    PROCESS_SESSION_EVENT(zh, ZOO_CONNECTED_STATE);
                }
            }
            zh->input_buffer = 0;
        } else {
            // zookeeper_process was called but there was nothing to read
            // from the socket
            return ZNOTHING;
        }
    }
    return ZOK;
}

void api_prolog(zhandle_t* zh)
{
    inc_ref_counter(zh,1);
}

int api_epilog(zhandle_t *zh,int rc)
{
    if(inc_ref_counter(zh,-1)==0 && zh->close_requested!=0)
        zookeeper_close(zh);
    return rc;
}

static __attribute__((unused)) void print_completion_queue(zhandle_t *zh)
{
    completion_list_t* cptr;

    if(logLevel<ZOO_LOG_LEVEL_DEBUG) return;

    fprintf(LOGSTREAM,"Completion queue: ");
    if (zh->sent_requests.head==0) {
        fprintf(LOGSTREAM,"empty\n");
        return;
    }

    cptr=zh->sent_requests.head;
    while(cptr){
        fprintf(LOGSTREAM,"%d,",cptr->xid);
        cptr=cptr->next;
    }
    fprintf(LOGSTREAM,"end\n");
}

//#ifdef THREADED
// IO thread queues session events to be processed by the completion thread
static int queue_session_event(zhandle_t *zh, int state)
{
    int rc;
    struct WatcherEvent evt = { ZOO_SESSION_EVENT, state, "" };
    struct ReplyHeader hdr = { WATCHER_EVENT_XID, 0, 0 };
    struct oarchive *oa;
    completion_list_t *cptr;

    if ((oa=create_buffer_oarchive())==NULL) {
        LOG_ERROR(("out of memory"));
        goto error;
    }
    rc = serialize_ReplyHeader(oa, "hdr", &hdr);
    rc = rc<0?rc: serialize_WatcherEvent(oa, "event", &evt);
    if(rc<0){
        close_buffer_oarchive(&oa, 1);
        goto error;
    }
    cptr = create_completion_entry(WATCHER_EVENT_XID,-1,0,0,0);
    cptr->buffer = allocate_buffer(get_buffer(oa), get_buffer_len(oa));
    cptr->buffer->curr_offset = get_buffer_len(oa);
    if (!cptr->buffer) {
        free(cptr);
        close_buffer_oarchive(&oa, 1);
        goto error;
    }
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);
    cptr->c.watcher_result = collectWatchers(zh, ZOO_SESSION_EVENT, "");
    queue_completion(&zh->completions_to_process, cptr, 0);
    if (process_async(zh->outstanding_sync)) {
        process_completions(zh);
    }
    return ZOK;
error:
    errno=ENOMEM;
    return ZSYSTEMERROR;
}
//#endif

completion_list_t *dequeue_completion(completion_head_t *list)
{
    completion_list_t *cptr;
    lock_completion_list(list);
    cptr = list->head;
    if (cptr) {
        list->head = cptr->next;
        if (!list->head) {
            assert(list->last == cptr);
            list->last = 0;
        }
    }
    unlock_completion_list(list);
    return cptr;
}


/* handles async completion (both single- and multithreaded) */
void process_completions(zhandle_t *zh)
{
    completion_list_t *cptr;
    while ((cptr = dequeue_completion(&zh->completions_to_process)) != 0) {
        struct ReplyHeader hdr;
        buffer_list_t *bptr = cptr->buffer;
        struct iarchive *ia = create_buffer_iarchive(bptr->buffer,
                bptr->len);
        deserialize_ReplyHeader(ia, "hdr", &hdr);

        if (hdr.xid == WATCHER_EVENT_XID) {
            int type, state;
            struct WatcherEvent evt;
            deserialize_WatcherEvent(ia, "event", &evt);
            /* We are doing a notification, so there is no pending request */
            type = evt.type;
            state = evt.state;
            /* This is a notification so there aren't any pending requests */
            LOG_DEBUG(("Calling a watcher for node [%s], type = %d event=%s",
                       (evt.path==NULL?"NULL":evt.path), cptr->completion_type,
                       watcherEvent2String(type)));
            deliverWatchers(zh,type,state,evt.path, &cptr->c.watcher_result);
            deallocate_WatcherEvent(&evt);
        } else {
            int rc = hdr.err;
            switch (cptr->completion_type) {
            case COMPLETION_DATA:
                LOG_DEBUG(("Calling COMPLETION_DATA for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.data_result(rc, 0, 0, 0, cptr->data);
                } else {
                    struct GetDataResponse res;
                    deserialize_GetDataResponse(ia, "reply", &res);
                    cptr->c.data_result(rc, res.data.buff, res.data.len,
                            &res.stat, cptr->data);
                    deallocate_GetDataResponse(&res);
                }
                break;
            case COMPLETION_STAT:
                LOG_DEBUG(("Calling COMPLETION_STAT for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.stat_result(rc, 0, cptr->data);
                } else {
                    struct SetDataResponse res;
                    deserialize_SetDataResponse(ia, "reply", &res);
                    cptr->c.stat_result(rc, &res.stat, cptr->data);
                    deallocate_SetDataResponse(&res);
                }
                break;
            case COMPLETION_STRINGLIST:
                LOG_DEBUG(("Calling COMPLETION_STRINGLIST for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.strings_result(rc, 0, cptr->data);
                } else {
                    struct GetChildrenResponse res;
                    deserialize_GetChildrenResponse(ia, "reply", &res);
                    cptr->c.strings_result(rc, &res.children, cptr->data);
                    deallocate_GetChildrenResponse(&res);
                }
                break;
            case COMPLETION_STRINGLIST_STAT:
                LOG_DEBUG(("Calling COMPLETION_STRINGLIST_STAT for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.strings_stat_result(rc, 0, 0, cptr->data);
                } else {
                    struct GetChildren2Response res;
                    deserialize_GetChildren2Response(ia, "reply", &res);
                    cptr->c.strings_stat_result(rc, &res.children, &res.stat, cptr->data);
                    deallocate_GetChildren2Response(&res);
                }
                break;
            case COMPLETION_STRING:
                LOG_DEBUG(("Calling COMPLETION_STRING for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.string_result(rc, 0, cptr->data);
                } else {
                    struct CreateResponse res;
                    deserialize_CreateResponse(ia, "reply", &res);
                    cptr->c.string_result(rc, res.path, cptr->data);
                    deallocate_CreateResponse(&res);
                }
                break;
            case COMPLETION_ACLLIST:
                LOG_DEBUG(("Calling COMPLETION_ACLLIST for xid=%#x rc=%d",cptr->xid,rc));
                if (rc) {
                    cptr->c.acl_result(rc, 0, 0, cptr->data);
                } else {
                    struct GetACLResponse res;
                    deserialize_GetACLResponse(ia, "reply", &res);
                    cptr->c.acl_result(rc, &res.acl, &res.stat, cptr->data);
                    deallocate_GetACLResponse(&res);
                }
                break;
            case COMPLETION_VOID:
                LOG_DEBUG(("Calling COMPLETION_VOID for xid=%#x rc=%d",cptr->xid,rc));
                if (hdr.xid == PING_XID) {
                    // We want to skip the ping
                } else {
                    cptr->c.void_result(rc, cptr->data);
                }
                break;
            }
        }
        destroy_completion_entry(cptr);
        close_buffer_iarchive(&ia);
    }
}

static void isSocketReadable(zhandle_t* zh)
{
    struct pollfd fds;
    fds.fd = zh->fd;
    fds.events = POLLIN;
    if (poll(&fds,1,0)<=0) {
        // socket not readable -- no more responses to process
        zh->socket_readable.tv_sec=zh->socket_readable.tv_usec=0;
    }else{
        gettimeofday(&zh->socket_readable,0);
    }
}

static void checkResponseLatency(zhandle_t* zh)
{
    int delay;
    struct timeval now;

    if(zh->socket_readable.tv_sec==0)
        return;

    gettimeofday(&now,0);
    delay=calculate_interval(&zh->socket_readable, &now);
    if(delay>20)
        LOG_DEBUG(("The following server response has spent at least %dms sitting in the client socket recv buffer",delay));

    zh->socket_readable.tv_sec=zh->socket_readable.tv_usec=0;
}

int zookeeper_process(zhandle_t *zh, int events)
{
    buffer_list_t *bptr;
    int rc;

    if (zh==NULL)
        return ZBADARGUMENTS;
    if (is_unrecoverable(zh))
        return ZINVALIDSTATE;
    api_prolog(zh);
    IF_DEBUG(checkResponseLatency(zh));
    rc = check_events(zh, events);
    if (rc!=ZOK)
        return api_epilog(zh, rc);

    IF_DEBUG(isSocketReadable(zh));

    while (rc >= 0 && (bptr=dequeue_buffer(&zh->to_process))) {
        struct ReplyHeader hdr;
        struct iarchive *ia = create_buffer_iarchive(
                                    bptr->buffer, bptr->curr_offset);
        deserialize_ReplyHeader(ia, "hdr", &hdr);
        if (hdr.zxid > 0) {
            zh->last_zxid = hdr.zxid;
        } else {
            // fprintf(stderr, "Got %#x for %#x\n", hdr.zxid, hdr.xid);
        }

        if (hdr.xid == WATCHER_EVENT_XID) {
            struct WatcherEvent evt;
            int type = 0;
            char *path = NULL;
            completion_list_t *c = NULL;

            LOG_DEBUG(("Processing WATCHER_EVENT"));

            deserialize_WatcherEvent(ia, "event", &evt);
            type = evt.type;
            path = evt.path;
            /* We are doing a notification, so there is no pending request */
            c = create_completion_entry(WATCHER_EVENT_XID,-1,0,0,0);
            c->buffer = bptr;
            c->c.watcher_result = collectWatchers(zh, type, path);

            // We cannot free until now, otherwise path will become invalid
            deallocate_WatcherEvent(&evt);
            queue_completion(&zh->completions_to_process, c, 0);
        } else if (hdr.xid == SET_WATCHES_XID) {
            LOG_DEBUG(("Processing SET_WATCHES"));
            free_buffer(bptr);
        } else if (hdr.xid == AUTH_XID){
            LOG_DEBUG(("Processing AUTH_XID"));

            /* special handling for the AUTH response as it may come back
             * out-of-band */
            auth_completion_func(hdr.err,zh);
            free_buffer(bptr);
            /* authentication completion may change the connection state to
             * unrecoverable */
            if(is_unrecoverable(zh)){
                handle_error(zh, ZAUTHFAILED);
                close_buffer_iarchive(&ia);
                return api_epilog(zh, ZAUTHFAILED);
            }
        } else {
            int rc = hdr.err;
            /* Find the request corresponding to the response */
            completion_list_t *cptr = dequeue_completion(&zh->sent_requests);

            /* [ZOOKEEPER-804] Don't assert if zookeeper_close has been called. */
            if (zh->close_requested == 1) {
                if (cptr) {
                    destroy_completion_entry(cptr);
                    cptr = NULL;
                }
                return api_epilog(zh,ZINVALIDSTATE);
            }
            assert(cptr);
            /* The requests are going to come back in order */
            if (cptr->xid != hdr.xid) {
                LOG_DEBUG(("Processing unexpected or out-of-order response!"));

                // received unexpected (or out-of-order) response
                close_buffer_iarchive(&ia);
                free_buffer(bptr);
                // put the completion back on the queue (so it gets properly
                // signaled and deallocated) and disconnect from the server
                queue_completion(&zh->sent_requests,cptr,1);
                return handle_socket_error_msg(zh, __LINE__,ZRUNTIMEINCONSISTENCY,
                        "unexpected server response: expected %#x, but received %#x",
                        hdr.xid,cptr->xid);
            }

            activateWatcher(zh, cptr->watcher, rc);

            if (cptr->c.void_result != SYNCHRONOUS_MARKER) {
                if(hdr.xid == PING_XID){
                    int elapsed = 0;
                    struct timeval now;
                    gettimeofday(&now, 0);
                    elapsed = calculate_interval(&zh->last_ping, &now);
                    LOG_DEBUG(("Got ping response in %d ms", elapsed));

                    // Nothing to do with a ping response
                    free_buffer(bptr);
                    destroy_completion_entry(cptr);
                } else {
                    LOG_DEBUG(("Queueing asynchronous response"));

                    cptr->buffer = bptr;
                    queue_completion(&zh->completions_to_process, cptr, 0);
                }
            } else {
                struct sync_completion
                        *sc = (struct sync_completion*)cptr->data;
                sc->rc = rc;
                switch(cptr->completion_type) {
                case COMPLETION_DATA:
                    LOG_DEBUG(("Calling COMPLETION_DATA for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc==0) {
                        struct GetDataResponse res;
                        int len;
                        deserialize_GetDataResponse(ia, "reply", &res);
                        if (res.data.len <= sc->u.data.buff_len) {
                            len = res.data.len;
                        } else {
                            len = sc->u.data.buff_len;
                        }
                        sc->u.data.buff_len = len;
                        // check if len is negative
                        // just of NULL which is -1 int
                        if (len == -1) {
                            sc->u.data.buffer = NULL;
                        } else {
                            memcpy(sc->u.data.buffer, res.data.buff, len);
                        }
                        sc->u.data.stat = res.stat;
                        deallocate_GetDataResponse(&res);
                    }
                    break;
                case COMPLETION_STAT:
                    LOG_DEBUG(("Calling COMPLETION_STAT for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc == 0) {
                        struct SetDataResponse res;
                        deserialize_SetDataResponse(ia, "reply", &res);
                        sc->u.stat = res.stat;
                        deallocate_SetDataResponse(&res);
                    }
                    break;
                case COMPLETION_STRINGLIST:
                    LOG_DEBUG(("Calling COMPLETION_STRINGLIST for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc == 0) {
                        struct GetChildrenResponse res;
                        deserialize_GetChildrenResponse(ia, "reply", &res);
                        sc->u.strs2 = res.children;
                        /* We don't deallocate since we are passing it back */
                        // deallocate_GetChildrenResponse(&res);
                    }
                    break;
                case COMPLETION_STRINGLIST_STAT:
                    LOG_DEBUG(("Calling COMPLETION_STRINGLIST_STAT for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc == 0) {
                        struct GetChildren2Response res;
                        deserialize_GetChildren2Response(ia, "reply", &res);
                        sc->u.strs_stat.strs2 = res.children;
                        sc->u.strs_stat.stat2 = res.stat;
                        /* We don't deallocate since we are passing it back */
                        // deallocate_GetChildren2Response(&res);
                    }
                    break;
                case COMPLETION_STRING:
                    LOG_DEBUG(("Calling COMPLETION_STRING for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc == 0) {
                        struct CreateResponse res;
                        int len;
                        deserialize_CreateResponse(ia, "reply", &res);
                        len = strlen(res.path) + 1;
                        if (len > sc->u.str.str_len) {
                            len = sc->u.str.str_len;
                        }
                        if (len > 0) {
                            memcpy(sc->u.str.str, res.path, len - 1);
                            sc->u.str.str[len - 1] = '\0';
                        }
                        deallocate_CreateResponse(&res);
                    }
                    break;
                case COMPLETION_ACLLIST:
                    LOG_DEBUG(("Calling COMPLETION_ACLLIST for xid=%#x rc=%d",
                               cptr->xid, rc));
                    if (rc == 0) {
                        struct GetACLResponse res;
                        deserialize_GetACLResponse(ia, "reply", &res);
                        sc->u.acl.acl = res.acl;
                        sc->u.acl.stat = res.stat;
                        /* We don't deallocate since we are passing it back */
                        //deallocate_GetACLResponse(&res);
                    }
                    break;
                case COMPLETION_VOID:
                    LOG_DEBUG(("Calling COMPLETION_VOID for xid=%#x rc=%d",
                               cptr->xid, rc));
                    break;
                default:
                    LOG_DEBUG(("UNKNOWN response type xid=%#x rc=%d",
                               cptr->xid, rc));
                    break;
                }
                notify_sync_completion(sc);
                free_buffer(bptr);
                zh->outstanding_sync--;
                destroy_completion_entry(cptr);
            }
        }

        close_buffer_iarchive(&ia);

    }
    if (process_async(zh->outstanding_sync)) {
        process_completions(zh);
    }
    return api_epilog(zh,ZOK);}

int zoo_state(zhandle_t *zh)
{
    if(zh!=0)
        return zh->state;
    return 0;
}

static watcher_registration_t* create_watcher_registration(const char* path,
        result_checker_fn checker,watcher_fn watcher,void* ctx){
    watcher_registration_t* wo;
    if(watcher==0)
        return 0;
    wo=calloc(1,sizeof(watcher_registration_t));
    wo->path=strdup(path);
    wo->watcher=watcher;
    wo->context=ctx;
    wo->checker=checker;
    return wo;
}

static void destroy_watcher_registration(watcher_registration_t* wo){
    if(wo!=0){
        free((void*)wo->path);
        free(wo);
    }
}

static completion_list_t* create_completion_entry(int xid, int completion_type,
        const void *dc, const void *data,watcher_registration_t* wo)
{
    completion_list_t *c = calloc(1,sizeof(completion_list_t));
    if (!c) {
        LOG_ERROR(("out of memory"));
        return 0;
    }
    c->completion_type = completion_type;
    c->data = data;
    switch(c->completion_type) {
    case COMPLETION_VOID:
        c->c.void_result = (void_completion_t)dc;
        break;
    case COMPLETION_STRING:
        c->c.string_result = (string_completion_t)dc;
        break;
    case COMPLETION_DATA:
        c->c.data_result = (data_completion_t)dc;
        break;
    case COMPLETION_STAT:
        c->c.stat_result = (stat_completion_t)dc;
        break;
    case COMPLETION_STRINGLIST:
        c->c.strings_result = (strings_completion_t)dc;
        break;
    case COMPLETION_STRINGLIST_STAT:
        c->c.strings_stat_result = (strings_stat_completion_t)dc;
        break;
    case COMPLETION_ACLLIST:
        c->c.acl_result = (acl_completion_t)dc;
        break;
    }
    c->xid = xid;
    c->watcher = wo;

    return c;
}

static void destroy_completion_entry(completion_list_t* c){
    if(c!=0){
        destroy_watcher_registration(c->watcher);
        if(c->buffer!=0)
            free_buffer(c->buffer);
        free(c);
    }
}

static void queue_completion_nolock(completion_head_t *list, 
                                    completion_list_t *c,
                                    int add_to_front) 
{
    c->next = 0;
    /* appending a new entry to the back of the list */
    if (list->last) {
        assert(list->head);
        // List is not empty
        if (!add_to_front) {
            list->last->next = c;
            list->last = c;
        } else {
            c->next = list->head;
            list->head = c;
        }
    } else {
        // List is empty
        assert(!list->head);
        list->head = c;
        list->last = c;
    }
}

static void queue_completion(completion_head_t *list, completion_list_t *c,
        int add_to_front)
{

    lock_completion_list(list);
    queue_completion_nolock(list, c, add_to_front);
    unlock_completion_list(list);
}

static int add_completion(zhandle_t *zh, int xid, int completion_type,
        const void *dc, const void *data, int add_to_front,
        watcher_registration_t* wo)
{
    completion_list_t *c =create_completion_entry(xid, completion_type, dc,
            data,wo);
    int rc = 0;
    if (!c)
        return ZSYSTEMERROR;
    lock_completion_list(&zh->sent_requests);
    if (zh->close_requested != 1) {
        queue_completion_nolock(&zh->sent_requests, c, add_to_front);
        if (dc == SYNCHRONOUS_MARKER) {
            zh->outstanding_sync++;
        }
        rc = ZOK;
    } else {
        free(c);
        rc = ZINVALIDSTATE;
    }
    unlock_completion_list(&zh->sent_requests);
    return rc;
}

static int add_data_completion(zhandle_t *zh, int xid, data_completion_t dc,
        const void *data,watcher_registration_t* wo)
{
    return add_completion(zh, xid, COMPLETION_DATA, dc, data, 0,wo);
}

static int add_stat_completion(zhandle_t *zh, int xid, stat_completion_t dc,
        const void *data,watcher_registration_t* wo)
{
    return add_completion(zh, xid, COMPLETION_STAT, dc, data, 0,wo);
}

static int add_strings_completion(zhandle_t *zh, int xid,
        strings_completion_t dc, const void *data,watcher_registration_t* wo)
{
    return add_completion(zh, xid, COMPLETION_STRINGLIST, dc, data, 0,wo);
}

static int add_strings_stat_completion(zhandle_t *zh, int xid,
        strings_stat_completion_t dc, const void *data,watcher_registration_t* wo)
{
    return add_completion(zh, xid, COMPLETION_STRINGLIST_STAT, dc, data, 0,wo);
}

static int add_acl_completion(zhandle_t *zh, int xid, acl_completion_t dc,
        const void *data)
{
    return add_completion(zh, xid, COMPLETION_ACLLIST, dc, data, 0,0);
}

static int add_void_completion(zhandle_t *zh, int xid, void_completion_t dc,
        const void *data)
{
    return add_completion(zh, xid, COMPLETION_VOID, dc, data, 0,0);
}

static int add_string_completion(zhandle_t *zh, int xid,
        string_completion_t dc, const void *data)
{
    return add_completion(zh, xid, COMPLETION_STRING, dc, data, 0,0);
}

int zookeeper_close(zhandle_t *zh)
{
    int rc=ZOK;
    if (zh==0)
        return ZBADARGUMENTS;

    zh->close_requested=1;
    if (inc_ref_counter(zh,0)!=0) {
	/* Signal any syncronous completions before joining the threads */
        enter_critical(zh);
        free_completions(zh,1,ZCLOSING);
        leave_critical(zh);

        adaptor_finish(zh);
        return ZOK;
    }
    if(zh->state==ZOO_CONNECTED_STATE){
        struct oarchive *oa;
        struct RequestHeader h = { .xid = get_xid(), .type = CLOSE_OP};
        LOG_INFO(("Closing zookeeper sessionId=%#llx to [%s]\n",
                zh->client_id.client_id,format_current_endpoint_info(zh)));
        oa = create_buffer_oarchive();
        rc = serialize_RequestHeader(oa, "header", &h);
        rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
                get_buffer_len(oa));
        /* We queued the buffer, so don't free it */
        close_buffer_oarchive(&oa, 0);
        if (rc < 0) {
            rc = ZMARSHALLINGERROR;
            goto finish;
        }

        /* make sure the close request is sent; we set timeout to an arbitrary
         * (but reasonable) number of milliseconds since we want the call to block*/
        rc=adaptor_send_queue(zh, 3000);
    }else{
        LOG_INFO(("Freeing zookeeper resources for sessionId=%#llx\n",
                zh->client_id.client_id));
        rc = ZOK;
    }

finish:
    destroy(zh);
    adaptor_destroy(zh);
    free(zh);
    return rc;
}

static int isValidPath(const char* path, const int flags) {
    int len = 0;
    char lastc = '/';
    char c;
    int i = 0;

  if (path == 0)
    return 0;
  len = strlen(path);
  if (len == 0)
    return 0;
  if (path[0] != '/')
    return 0;
  if (len == 1) // done checking - it's the root
    return 1;
  if (path[len - 1] == '/' && !(flags & ZOO_SEQUENCE))
    return 0;

  i = 1;
  for (; i < len; lastc = path[i], i++) {
    c = path[i];

    if (c == 0) {
      return 0;
    } else if (c == '/' && lastc == '/') {
      return 0;
    } else if (c == '.' && lastc == '.') {
      if (path[i-2] == '/' && (((i + 1 == len) && !(flags & ZOO_SEQUENCE))
                               || path[i+1] == '/')) {
        return 0;
      }
    } else if (c == '.') {
      if ((path[i-1] == '/') && (((i + 1 == len) && !(flags & ZOO_SEQUENCE))
                                 || path[i+1] == '/')) {
        return 0;
      }
    } else if (c > 0x00 && c < 0x1f) {
      return 0;
    }
  }

  return 1;
}

int zoo_aget(zhandle_t *zh, const char *path, int watch, data_completion_t dc,
        const void *data)
{
    return zoo_awget(zh,path,watch?zh->watcher:0,zh->context,dc,data);
}

int zoo_awget(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        data_completion_t dc, const void *data)
{
    struct oarchive *oa;
    char *server_path = prepend_string(zh, path);
    struct RequestHeader h = { .xid = get_xid(), .type = GETDATA_OP};
    struct GetDataRequest req =  { (char*)server_path, watcher!=0 };
    int rc;

    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa=create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_GetDataRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_data_completion(zh, h.xid, dc, data,
        create_watcher_registration(server_path,data_result_checker,watcher,watcherCtx));
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_aset(zhandle_t *zh, const char *path, const char *buffer, int buflen,
        int version, stat_completion_t dc, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = SETDATA_OP};
    struct SetDataRequest req;
    int rc;
    char *server_path;
    server_path = prepend_string(zh, path);

    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    req.data.buff = (char*)buffer;
    req.data.len = buflen;
    req.version = version;
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_SetDataRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_stat_completion(zh, h.xid, dc, data,0);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_acreate(zhandle_t *zh, const char *path, const char *value,
        int valuelen, const struct ACL_vector *acl_entries, int flags,
        string_completion_t completion, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = CREATE_OP };
    struct CreateRequest req;
    int rc;
    char *server_path;

    server_path = prepend_string(zh, path);
    if (zh==0 || !isValidPath(server_path, flags)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    req.flags = flags;
    req.data.buff = (char*)value;
    req.data.len = valuelen;
    if (acl_entries == 0) {
        req.acl.count = 0;
        req.acl.data = 0;
    } else {
        req.acl = *acl_entries;
    }
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_CreateRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_string_completion(zh, h.xid, completion, data);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_adelete(zhandle_t *zh, const char *path, int version,
        void_completion_t completion, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = DELETE_OP};
    struct DeleteRequest req;
    int rc;
    char *server_path;

    server_path = prepend_string(zh, path);
    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    req.version = version;
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_DeleteRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_void_completion(zh, h.xid, completion, data);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_aexists(zhandle_t *zh, const char *path, int watch,
        stat_completion_t sc, const void *data)
{
    return zoo_awexists(zh,path,watch?zh->watcher:0,zh->context,sc,data);
}

int zoo_awexists(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        stat_completion_t completion, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = EXISTS_OP };
    char *server_path = prepend_string(zh, path);
    struct ExistsRequest req  = {(char*)server_path, watcher!=0 };
    int rc;

    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_ExistsRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_stat_completion(zh, h.xid, completion, data,
        create_watcher_registration(server_path,exists_result_checker,
                watcher,watcherCtx));
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

static int zoo_awget_children_(zhandle_t *zh, const char *path,
         watcher_fn watcher, void* watcherCtx,
         strings_completion_t sc,
         const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = GETCHILDREN_OP};
    char * server_path = prepend_string(zh, path);
    struct GetChildrenRequest req = {(char*)server_path, watcher!=0 };
    int rc;

    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_GetChildrenRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_strings_completion(zh, h.xid, sc, data,
            create_watcher_registration(server_path,child_result_checker,watcher,watcherCtx));
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_aget_children(zhandle_t *zh, const char *path, int watch,
        strings_completion_t dc, const void *data)
{
    return zoo_awget_children_(zh,path,watch?zh->watcher:0,zh->context,dc,data);
}

int zoo_awget_children(zhandle_t *zh, const char *path,
         watcher_fn watcher, void* watcherCtx,
         strings_completion_t dc,
         const void *data)
{
    return zoo_awget_children_(zh,path,watcher,watcherCtx,dc,data);
}

static int zoo_awget_children2_(zhandle_t *zh, const char *path,
         watcher_fn watcher, void* watcherCtx,
         strings_stat_completion_t ssc,
         const void *data)
{
    /* invariant: (sc == NULL) != (sc == NULL) */
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = GETCHILDREN2_OP};
    char * server_path = prepend_string(zh, path);
    struct GetChildren2Request req2 = {(char*)server_path, watcher!=0 };
    int rc;

    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_GetChildren2Request(oa, "req", &req2);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_strings_stat_completion(zh, h.xid, ssc, data,
            create_watcher_registration(server_path,child_result_checker,watcher,watcherCtx));
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_aget_children2(zhandle_t *zh, const char *path, int watch,
        strings_stat_completion_t dc, const void *data)
{
    return zoo_awget_children2_(zh,path,watch?zh->watcher:0,zh->context,dc,data);
}

int zoo_awget_children2(zhandle_t *zh, const char *path,
         watcher_fn watcher, void* watcherCtx,
         strings_stat_completion_t dc,
         const void *data)
{
    return zoo_awget_children2_(zh,path,watcher,watcherCtx,dc,data);
}

int zoo_async(zhandle_t *zh, const char *path,
        string_completion_t completion, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = SYNC_OP};
    struct SyncRequest req;
    int rc;
    char *server_path;

    server_path = prepend_string(zh, path);
    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_SyncRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_string_completion(zh, h.xid, completion, data);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}


int zoo_aget_acl(zhandle_t *zh, const char *path, acl_completion_t completion,
        const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = GETACL_OP};
    struct GetACLRequest req;
    int rc;
    char *server_path;

    server_path = prepend_string(zh, path);
    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_GetACLRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_acl_completion(zh, h.xid, completion, data);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

int zoo_aset_acl(zhandle_t *zh, const char *path, int version,
        struct ACL_vector *acl, void_completion_t completion, const void *data)
{
    struct oarchive *oa;
    struct RequestHeader h = { .xid = get_xid(), .type = SETACL_OP};
    struct SetACLRequest req;
    int rc;
    char *server_path;

    server_path = prepend_string(zh, path);
    if (zh==0 || !isValidPath(server_path, 0)) {
        free_duplicate_path(server_path, path);
        return ZBADARGUMENTS;
    }
    if (is_unrecoverable(zh)) {
        free_duplicate_path(server_path, path);
        return ZINVALIDSTATE;
    }
    oa = create_buffer_oarchive();
    req.path = (char*)server_path;
    req.acl = *acl;
    req.version = version;
    rc = serialize_RequestHeader(oa, "header", &h);
    rc = rc < 0 ? rc : serialize_SetACLRequest(oa, "req", &req);
    enter_critical(zh);
    rc = rc < 0 ? rc : add_void_completion(zh, h.xid, completion, data);
    rc = rc < 0 ? rc : queue_buffer_bytes(&zh->to_send, get_buffer(oa),
            get_buffer_len(oa));
    leave_critical(zh);
    free_duplicate_path(server_path, path);
    /* We queued the buffer, so don't free it */
    close_buffer_oarchive(&oa, 0);

    LOG_DEBUG(("Sending request xid=%#x for path [%s] to %s",h.xid,path,
            format_current_endpoint_info(zh)));
    /* make a best (non-blocking) effort to send the requests asap */
    adaptor_send_queue(zh, 0);
    return (rc < 0)?ZMARSHALLINGERROR:ZOK;
}

/* specify timeout of 0 to make the function non-blocking */
/* timeout is in milliseconds */
int flush_send_queue(zhandle_t*zh, int timeout)
{
    int rc= ZOK;
    struct timeval started;
    gettimeofday(&started,0);
    // we can't use dequeue_buffer() here because if (non-blocking) send_buffer()
    // returns EWOULDBLOCK we'd have to put the buffer back on the queue.
    // we use a recursive lock instead and only dequeue the buffer if a send was
    // successful
    lock_buffer_list(&zh->to_send);
    while (zh->to_send.head != 0&& zh->state == ZOO_CONNECTED_STATE) {
        if(timeout!=0){
            int elapsed;
            struct pollfd fds;
            struct timeval now;
            gettimeofday(&now,0);
            elapsed=calculate_interval(&started,&now);
            if (elapsed>timeout) {
                rc = ZOPERATIONTIMEOUT;
                break;
            }
            fds.fd = zh->fd;
            fds.events = POLLOUT;
            fds.revents = 0;
            rc = poll(&fds, 1, timeout-elapsed);
            if (rc<=0) {
                /* timed out or an error or POLLERR */
                rc = rc==0 ? ZOPERATIONTIMEOUT : ZSYSTEMERROR;
                break;
            }
        }

        rc = send_buffer(zh->fd, zh->to_send.head);
        if(rc==0 && timeout==0){
            /* send_buffer would block while sending this buffer */
            rc = ZOK;
            break;
        }
        if (rc < 0) {
            rc = ZCONNECTIONLOSS;
            break;
        }
        // if the buffer has been sent successfully, remove it from the queue
        if (rc > 0)
            remove_buffer(&zh->to_send);
        gettimeofday(&zh->last_send, 0);
        rc = ZOK;
    }
    unlock_buffer_list(&zh->to_send);
    return rc;
}

const char* zerror(int c)
{
    switch (c){
    case ZOK:
      return "ok";
    case ZSYSTEMERROR:
      return "system error";
    case ZRUNTIMEINCONSISTENCY:
      return "run time inconsistency";
    case ZDATAINCONSISTENCY:
      return "data inconsistency";
    case ZCONNECTIONLOSS:
      return "connection loss";
    case ZMARSHALLINGERROR:
      return "marshalling error";
    case ZUNIMPLEMENTED:
      return "unimplemented";
    case ZOPERATIONTIMEOUT:
      return "operation timeout";
    case ZBADARGUMENTS:
      return "bad arguments";
    case ZINVALIDSTATE:
      return "invalid zhandle state";
    case ZAPIERROR:
      return "api error";
    case ZNONODE:
      return "no node";
    case ZNOAUTH:
      return "not authenticated";
    case ZBADVERSION:
      return "bad version";
    case  ZNOCHILDRENFOREPHEMERALS:
      return "no children for ephemerals";
    case ZNODEEXISTS:
      return "node exists";
    case ZNOTEMPTY:
      return "not empty";
    case ZSESSIONEXPIRED:
      return "session expired";
    case ZINVALIDCALLBACK:
      return "invalid callback";
    case ZINVALIDACL:
      return "invalid acl";
    case ZAUTHFAILED:
      return "authentication failed";
    case ZCLOSING:
      return "zookeeper is closing";
    case ZNOTHING:
      return "(not error) no server responses to process";
    case ZSESSIONMOVED:
      return "session moved to another server, so operation is ignored";
    }
    if (c > 0) {
      return strerror(c);
    }
    return "unknown error";
}

int zoo_add_auth(zhandle_t *zh,const char* scheme,const char* cert,
        int certLen,void_completion_t completion, const void *data)
{
    struct buffer auth;
    auth_info *authinfo;
    if(scheme==NULL || zh==NULL)
        return ZBADARGUMENTS;

    if (is_unrecoverable(zh))
        return ZINVALIDSTATE;

    // [ZOOKEEPER-800] zoo_add_auth should return ZINVALIDSTATE if
    // the connection is closed. 
    if (zoo_state(zh) == 0) {
        return ZINVALIDSTATE;
    }

    if(cert!=NULL && certLen!=0){
        auth.buff=calloc(1,certLen);
        if(auth.buff==0) {
            return ZSYSTEMERROR;
        }
        memcpy(auth.buff,cert,certLen);
        auth.len=certLen;
    } else {
        auth.buff = 0;
        auth.len = 0;
    }

    zoo_lock_auth(zh);
    authinfo = (auth_info*) malloc(sizeof(auth_info));
    authinfo->scheme=strdup(scheme);
    authinfo->auth=auth;
    authinfo->completion=completion;
    authinfo->data=data;
    authinfo->next = NULL;
    add_last_auth(&zh->auth_h, authinfo);
    zoo_unlock_auth(zh);

    if(zh->state == ZOO_CONNECTED_STATE || zh->state == ZOO_ASSOCIATING_STATE)
        return send_last_auth_info(zh);

    return ZOK;
}

static const char* format_endpoint_info(const struct sockaddr_storage* ep)
{
    static char buf[128];
    char addrstr[128];
    void *inaddr;
    int port;
    if(ep==0)
        return "null";

#if defined(AF_INET6)
    if(ep->ss_family==AF_INET6){
        inaddr=&((struct sockaddr_in6*)ep)->sin6_addr;
        port=((struct sockaddr_in6*)ep)->sin6_port;
    } else {
#endif
        inaddr=&((struct sockaddr_in*)ep)->sin_addr;
        port=((struct sockaddr_in*)ep)->sin_port;
#if defined(AF_INET6)
    }
#endif
    inet_ntop(ep->ss_family,inaddr,addrstr,sizeof(addrstr)-1);
    sprintf(buf,"%s:%d",addrstr,ntohs(port));
    return buf;
}

static const char* format_current_endpoint_info(zhandle_t* zh)
{
    return format_endpoint_info(&zh->addrs[zh->connect_index]);
}

void zoo_deterministic_conn_order(int yesOrNo)
{
    disable_conn_permute=yesOrNo;
}

/* ****************************************************************************
 * sync API
 */
int zoo_create(zhandle_t *zh, const char *path, const char *value,
        int valuelen, const struct ACL_vector *acl, int flags,
        char *path_buffer, int path_buffer_len)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    sc->u.str.str = path_buffer;
    sc->u.str.str_len = path_buffer_len;
    rc=zoo_acreate(zh, path, value, valuelen, acl, flags, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_delete(zhandle_t *zh, const char *path, int version)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc=zoo_adelete(zh, path, version, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_exists(zhandle_t *zh, const char *path, int watch, struct Stat *stat)
{
    return zoo_wexists(zh,path,watch?zh->watcher:0,zh->context,stat);
}

int zoo_wexists(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx, struct Stat *stat)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc=zoo_awexists(zh,path,watcher,watcherCtx,SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0&& stat) {
            *stat = sc->u.stat;
        }
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_get(zhandle_t *zh, const char *path, int watch, char *buffer,
        int* buffer_len, struct Stat *stat)
{
    return zoo_wget(zh,path,watch?zh->watcher:0,zh->context,
            buffer,buffer_len,stat);
}

int zoo_wget(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        char *buffer, int* buffer_len, struct Stat *stat)
{
    struct sync_completion *sc;
    int rc=0;

    if(buffer_len==NULL)
        return ZBADARGUMENTS;
    if((sc=alloc_sync_completion())==NULL)
        return ZSYSTEMERROR;

    sc->u.data.buffer = buffer;
    sc->u.data.buff_len = *buffer_len;
    rc=zoo_awget(zh, path, watcher, watcherCtx, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0) {
            if(stat)
                *stat = sc->u.data.stat;
            *buffer_len = sc->u.data.buff_len;
        }
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_set(zhandle_t *zh, const char *path, const char *buffer, int buflen,
        int version)
{
  return zoo_set2(zh, path, buffer, buflen, version, 0);
}

int zoo_set2(zhandle_t *zh, const char *path, const char *buffer, int buflen,
        int version, struct Stat *stat)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc=zoo_aset(zh, path, buffer, buflen, version, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0 && stat) {
            *stat = sc->u.stat;
        }
    }
    free_sync_completion(sc);
    return rc;
}

static int zoo_wget_children_(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        struct String_vector *strings)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc= zoo_awget_children (zh, path, watcher, watcherCtx, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0) {
            if (strings) {
                *strings = sc->u.strs2;
            } else {
                deallocate_String_vector(&sc->u.strs2);
            }
        }
    }
    free_sync_completion(sc);
    return rc;
}

static int zoo_wget_children2_(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        struct String_vector *strings, struct Stat *stat)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc= zoo_awget_children2(zh, path, watcher, watcherCtx, SYNCHRONOUS_MARKER, sc);

    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0) {
            *stat = sc->u.strs_stat.stat2;
            if (strings) {
                *strings = sc->u.strs_stat.strs2;
            } else {
                deallocate_String_vector(&sc->u.strs_stat.strs2);
            }
        }
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_get_children(zhandle_t *zh, const char *path, int watch,
        struct String_vector *strings)
{
    return zoo_wget_children_(zh,path,watch?zh->watcher:0,zh->context,strings);
}

int zoo_wget_children(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        struct String_vector *strings)
{
    return zoo_wget_children_(zh,path,watcher,watcherCtx,strings);
}

int zoo_get_children2(zhandle_t *zh, const char *path, int watch,
        struct String_vector *strings, struct Stat *stat)
{
    return zoo_wget_children2_(zh,path,watch?zh->watcher:0,zh->context,strings,stat);
}

int zoo_wget_children2(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx,
        struct String_vector *strings, struct Stat *stat)
{
    return zoo_wget_children2_(zh,path,watcher,watcherCtx,strings,stat);
}

int zoo_get_acl(zhandle_t *zh, const char *path, struct ACL_vector *acl,
        struct Stat *stat)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc=zoo_aget_acl(zh, path, SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
        if (rc == 0&& stat) {
            *stat = sc->u.acl.stat;
        }
        if (rc == 0) {
            if (acl) {
                *acl = sc->u.acl.acl;
            } else {
                deallocate_ACL_vector(&sc->u.acl.acl);
            }
        }
    }
    free_sync_completion(sc);
    return rc;
}

int zoo_set_acl(zhandle_t *zh, const char *path, int version,
        const struct ACL_vector *acl)
{
    struct sync_completion *sc = alloc_sync_completion();
    int rc;
    if (!sc) {
        return ZSYSTEMERROR;
    }
    rc=zoo_aset_acl(zh, path, version, (struct ACL_vector*)acl,
            SYNCHRONOUS_MARKER, sc);
    if(rc==ZOK){
        wait_sync_completion(sc);
        rc = sc->rc;
    }
    free_sync_completion(sc);
    return rc;
}