service.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2016 GNUnet e.V.
 
     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.
 
     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Affero General Public License for more details.
 
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_constants.h"
#include "gnunet_resolver_service.h"
#include "speedup.h"
 
#if HAVE_MALLINFO2
#include <malloc.h>
#include "gauger.h"
#endif
 
 
#define LOG(kind, ...) GNUNET_log_from (kind, "util-service", __VA_ARGS__)
 
#define LOG_STRERROR(kind, syscall) \
        GNUNET_log_from_strerror (kind, "util-service", syscall)
 
#define LOG_STRERROR_FILE(kind, syscall, filename) \
        GNUNET_log_from_strerror_file (kind, "util-service", syscall, filename)
 
 
struct ServiceListenContext
{
  struct ServiceListenContext *next;
 
  struct ServiceListenContext *prev;
 
  struct GNUNET_SERVICE_Handle *sh;
 
  struct GNUNET_NETWORK_Handle *listen_socket;
 
  struct GNUNET_SCHEDULER_Task *listen_task;
};
 
 
enum SuspendReason
{
  SUSPEND_STATE_NONE = 0,
 
  SUSPEND_STATE_APP = 1,
 
  SUSPEND_STATE_EMFILE = 2,
 
  SUSPEND_STATE_APP_AND_EMFILE = 3,
 
  SUSPEND_STATE_SHUTDOWN = 4
};
 
 
struct GNUNET_SERVICE_Handle
{
  const struct GNUNET_CONFIGURATION_Handle *cfg;
 
  const char *service_name;
 
  GNUNET_SERVICE_InitCallback service_init_cb;
 
  GNUNET_SERVICE_ConnectHandler connect_cb;
 
  GNUNET_SERVICE_DisconnectHandler disconnect_cb;
 
  void *cb_cls;
 
  struct ServiceListenContext *slc_head;
 
  struct ServiceListenContext *slc_tail;
 
  struct GNUNET_SERVICE_Client *clients_head;
 
  struct GNUNET_SERVICE_Client *clients_tail;
 
  struct GNUNET_MQ_MessageHandler *handlers;
 
  void *task_cls;
 
 
  struct GNUNET_STRINGS_IPv4NetworkPolicy *v4_denied;
 
  struct GNUNET_STRINGS_IPv6NetworkPolicy *v6_denied;
 
  struct GNUNET_STRINGS_IPv4NetworkPolicy *v4_allowed;
 
  struct GNUNET_STRINGS_IPv6NetworkPolicy *v6_allowed;
 
  int match_uid;
 
  int match_gid;
 
  enum SuspendReason suspend_state;
 
  enum GNUNET_SERVICE_Options options;
 
  int ready_confirm_fd;
 
  bool require_found;
};
 
 
struct GNUNET_SERVICE_Client
{
  struct GNUNET_SERVICE_Client *next;
 
  struct GNUNET_SERVICE_Client *prev;
 
  struct GNUNET_SERVICE_Handle *sh;
 
  struct GNUNET_NETWORK_Handle *sock;
 
  struct GNUNET_MQ_Handle *mq;
 
  struct GNUNET_MessageStreamTokenizer *mst;
 
  struct GNUNET_SCHEDULER_Task *warn_task;
 
  struct GNUNET_SCHEDULER_Task *drop_task;
 
  struct GNUNET_SCHEDULER_Task *recv_task;
 
  struct GNUNET_SCHEDULER_Task *send_task;
 
  const struct GNUNET_MessageHeader *msg;
 
  void *user_context;
 
  struct GNUNET_TIME_Absolute warn_start;
 
  size_t msg_pos;
 
  bool persist;
 
  bool is_monitor;
 
  bool needs_continue;
 
  uint16_t warn_type;
};
 
 
static enum GNUNET_GenericReturnValue
have_non_monitor_clients (struct GNUNET_SERVICE_Handle *sh)
{
  for (struct GNUNET_SERVICE_Client *client = sh->clients_head;
       NULL != client;
       client = client->next)
  {
    if (NULL != client->drop_task)
      continue;
    if (client->is_monitor)
      continue;
    return true;
  }
  return false;
}
 
 
static void
do_suspend (struct GNUNET_SERVICE_Handle *sh,
            enum SuspendReason sr)
{
  GNUNET_assert (0 == (sh->suspend_state & sr));
  sh->suspend_state |= sr;
  for (struct ServiceListenContext *slc = sh->slc_head;
       NULL != slc;
       slc = slc->next)
  {
    if (NULL != slc->listen_task)
    {
      GNUNET_SCHEDULER_cancel (slc->listen_task);
      slc->listen_task = NULL;
    }
  }
}
 
 
static void
service_shutdown (void *cls)
{
  struct GNUNET_SERVICE_Handle *sh = cls;
 
  switch (sh->options & GNUNET_SERVICE_OPTION_SHUTDOWN_BITMASK)
  {
  case GNUNET_SERVICE_OPTION_NONE:
    GNUNET_SERVICE_shutdown (sh);
    break;
  case GNUNET_SERVICE_OPTION_MANUAL_SHUTDOWN:
    /* This task should never be run if we are using
       the manual shutdown. */
    GNUNET_assert (0);
    break;
  case GNUNET_SERVICE_OPTION_SOFT_SHUTDOWN:
    if (0 == (sh->suspend_state & SUSPEND_STATE_SHUTDOWN))
      do_suspend (sh, SUSPEND_STATE_SHUTDOWN);
    if (! have_non_monitor_clients (sh))
      GNUNET_SERVICE_shutdown (sh);
    break;
  }
}
 
 
static bool
check_ipv4_listed (const struct GNUNET_STRINGS_IPv4NetworkPolicy *list,
                   const struct in_addr *add)
{
  for (unsigned int i = 0;
       0 != list[i].network.s_addr;
       i++)
  {
    if ( (add->s_addr & list[i].netmask.s_addr) ==
         (list[i].network.s_addr & list[i].netmask.s_addr) )
      return true;
  }
  return false;
}
 
 
static bool
check_ipv6_listed (const struct GNUNET_STRINGS_IPv6NetworkPolicy *list,
                   const struct in6_addr *ip)
{
  for (unsigned int i = 0;
       ! GNUNET_is_zero (&list[i].network);
       i++)
  {
    bool match = true;
    
    for (unsigned int j = 0; j < sizeof(struct in6_addr) / sizeof(int); j++)
      if (((((int *) ip)[j] & ((int *) &list[i].netmask)[j])) !=
          (((int *) &list[i].network)[j] & ((int *) &list[i].netmask)[j]))
      {
        match = false;
        break;
      }
    if (match)
      return true;
  }
  return false;
}
 
 
static void
do_send (void *cls)
{
  struct GNUNET_SERVICE_Client *client = cls;
  ssize_t ret;
  size_t left;
  const char *buf;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "service: sending message with type %u\n",
       ntohs (client->msg->type));
  client->send_task = NULL;
  buf = (const char *) client->msg;
  left = ntohs (client->msg->size) - client->msg_pos;
  ret = GNUNET_NETWORK_socket_send (client->sock,
                                    &buf[client->msg_pos],
                                    left);
  GNUNET_assert (ret <= (ssize_t) left);
  if (0 == ret)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG, "no data send");
    GNUNET_MQ_inject_error (client->mq, GNUNET_MQ_ERROR_WRITE);
    return;
  }
  if (-1 == ret)
  {
    if ((EAGAIN == errno) || (EINTR == errno))
    {
      /* ignore */
      ret = 0;
    }
    else
    {
      if (EPIPE != errno)
        GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "send");
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "socket send returned with error code %i",
           errno);
      GNUNET_MQ_inject_error (client->mq, GNUNET_MQ_ERROR_WRITE);
      return;
    }
  }
  if (0 == client->msg_pos)
  {
    GNUNET_MQ_impl_send_in_flight (client->mq);
  }
  client->msg_pos += ret;
  if (left > (size_t) ret)
  {
    GNUNET_assert (NULL == client->drop_task);
    client->send_task =
      GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      client->sock,
                                      &do_send,
                                      client);
    return;
  }
  GNUNET_MQ_impl_send_continue (client->mq);
}
 
 
static void
service_mq_send (struct GNUNET_MQ_Handle *mq,
                 const struct GNUNET_MessageHeader *msg,
                 void *impl_state)
{
  struct GNUNET_SERVICE_Client *client = impl_state;
 
  (void) mq;
  if (NULL != client->drop_task)
    return; /* we're going down right now, do not try to send */
  GNUNET_assert (NULL == client->send_task);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending message of type %u and size %u to client\n",
       ntohs (msg->type),
       ntohs (msg->size));
  client->msg = msg;
  client->msg_pos = 0;
  client->send_task = GNUNET_SCHEDULER_add_now (&do_send,
                                                client);
}
 
 
static void
service_mq_cancel (struct GNUNET_MQ_Handle *mq,
                   void *impl_state)
{
  struct GNUNET_SERVICE_Client *client = impl_state;
 
  (void) mq;
  GNUNET_assert (0 == client->msg_pos);
  client->msg = NULL;
  GNUNET_SCHEDULER_cancel (client->send_task);
  client->send_task = NULL;
}
 
 
static void
service_mq_error_handler (void *cls,
                          enum GNUNET_MQ_Error error)
{
  struct GNUNET_SERVICE_Client *client = cls;
  struct GNUNET_SERVICE_Handle *sh = client->sh;
 
  if ( (GNUNET_MQ_ERROR_NO_MATCH == error) &&
       (! sh->require_found) )
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "No handler for message of type %u found\n",
                (unsigned int) client->warn_type);
    GNUNET_SERVICE_client_continue (client);
    return;   /* ignore error */
  }
  GNUNET_SERVICE_client_drop (client);
}
 
 
static void
warn_no_client_continue (void *cls)
{
  struct GNUNET_SERVICE_Client *client = cls;
 
  GNUNET_break (
    0 !=
    client->warn_type); /* type should never be 0 here, as we don't use 0 */
  client->warn_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
                                                    &warn_no_client_continue,
                                                    client);
  LOG (
    GNUNET_ERROR_TYPE_WARNING,
    _ (
      "Processing code for message of type %u did not call `GNUNET_SERVICE_client_continue' after %s\n"),
    (unsigned int) client->warn_type,
    GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (
                                              client->warn_start),
                                            GNUNET_YES));
}
 
 
static int
service_client_mst_cb (void *cls,
                       const struct GNUNET_MessageHeader *message)
{
  struct GNUNET_SERVICE_Client *client = cls;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Received message of type %u and size %u from client\n",
       ntohs (message->type),
       ntohs (message->size));
  GNUNET_assert (! client->needs_continue);
  client->needs_continue = true;
  client->warn_type = ntohs (message->type);
  client->warn_start = GNUNET_TIME_absolute_get ();
  GNUNET_assert (NULL == client->warn_task);
  client->warn_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
                                                    &warn_no_client_continue,
                                                    client);
  GNUNET_MQ_inject_message (client->mq, message);
  if (NULL != client->drop_task)
    return GNUNET_SYSERR;
  return GNUNET_OK;
}
 
 
static void
service_client_recv (void *cls)
{
  struct GNUNET_SERVICE_Client *client = cls;
  enum GNUNET_GenericReturnValue ret;
 
  client->recv_task = NULL;
  ret = GNUNET_MST_read (client->mst,
                         client->sock,
                         GNUNET_NO,
                         GNUNET_YES);
  if (GNUNET_SYSERR == ret)
  {
    /* client closed connection (or IO error) */
    if (NULL == client->drop_task)
    {
      GNUNET_assert (! client->needs_continue);
      GNUNET_SERVICE_client_drop (client);
    }
    return;
  }
  if (GNUNET_NO == ret)
    return; /* more messages in buffer, wait for application
               to be done processing */
  GNUNET_assert (GNUNET_OK == ret);
  if (client->needs_continue)
    return;
  if (NULL != client->recv_task)
    return;
  /* MST needs more data, re-schedule read job */
  client->recv_task =
    GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                   client->sock,
                                   &service_client_recv,
                                   client);
}
 
 
static void
start_client (struct GNUNET_SERVICE_Handle *sh,
              struct GNUNET_NETWORK_Handle *csock)
{
  struct GNUNET_SERVICE_Client *client;
 
  client = GNUNET_new (struct GNUNET_SERVICE_Client);
  GNUNET_CONTAINER_DLL_insert (sh->clients_head,
                               sh->clients_tail,
                               client);
  client->sh = sh;
  client->sock = csock;
  client->mq = GNUNET_MQ_queue_for_callbacks (&service_mq_send,
                                              NULL,
                                              &service_mq_cancel,
                                              client,
                                              sh->handlers,
                                              &service_mq_error_handler,
                                              client);
  client->mst = GNUNET_MST_create (&service_client_mst_cb, client);
  if (NULL != sh->connect_cb)
    client->user_context = sh->connect_cb (sh->cb_cls, client, client->mq);
  GNUNET_MQ_set_handlers_closure (client->mq, client->user_context);
  client->recv_task =
    GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                   client->sock,
                                   &service_client_recv,
                                   client);
}
 
 
static void
accept_client (void *cls)
{
  struct ServiceListenContext *slc = cls;
  struct GNUNET_SERVICE_Handle *sh = slc->sh;
 
  slc->listen_task = NULL;
  while (1)
  {
    struct GNUNET_NETWORK_Handle *sock;
    const struct sockaddr_in *v4;
    const struct sockaddr_in6 *v6;
    struct sockaddr_storage sa;
    socklen_t addrlen;
    int ok;
 
    addrlen = sizeof(sa);
    sock = GNUNET_NETWORK_socket_accept (slc->listen_socket,
                                         (struct sockaddr *) &sa,
                                         &addrlen);
    if (NULL == sock)
    {
      if (EMFILE == errno)
        do_suspend (sh, SUSPEND_STATE_EMFILE);
      else if (EAGAIN != errno)
        GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                             "accept");
      break;
    }
    switch (sa.ss_family)
    {
    case AF_INET:
      GNUNET_assert (addrlen == sizeof(struct sockaddr_in));
      v4 = (const struct sockaddr_in *) &sa;
      ok = (((NULL == sh->v4_allowed) ||
             (check_ipv4_listed (sh->v4_allowed,
                                 &v4->sin_addr))) &&
            ((NULL == sh->v4_denied) ||
             (! check_ipv4_listed (sh->v4_denied,
                                   &v4->sin_addr))));
      break;
 
    case AF_INET6:
      GNUNET_assert (addrlen == sizeof(struct sockaddr_in6));
      v6 = (const struct sockaddr_in6 *) &sa;
      ok = (((NULL == sh->v6_allowed) ||
             (check_ipv6_listed (sh->v6_allowed,
                                 &v6->sin6_addr))) &&
            ((NULL == sh->v6_denied) ||
             (! check_ipv6_listed (sh->v6_denied,
                                   &v6->sin6_addr))));
      break;
 
    case AF_UNIX:
      ok = GNUNET_OK;     /* controlled using file-system ACL now */
      break;
 
    default:
      LOG (GNUNET_ERROR_TYPE_WARNING,
           _ ("Unknown address family %d\n"),
           sa.ss_family);
      return;
    }
    if (! ok)
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Service rejected incoming connection from %s due to policy.\n",
           GNUNET_a2s ((const struct sockaddr *) &sa, addrlen));
      GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
      continue;
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Service accepted incoming connection from %s.\n",
         GNUNET_a2s ((const struct sockaddr *) &sa, addrlen));
    start_client (slc->sh,
                  sock);
  }
  if (0 != sh->suspend_state)
    return;
  slc->listen_task =
    GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                   slc->listen_socket,
                                   &accept_client,
                                   slc);
}
 
 
static void
do_resume (struct GNUNET_SERVICE_Handle *sh,
           enum SuspendReason sr)
{
  GNUNET_assert ((SUSPEND_STATE_NONE == sr) || (0 != (sh->suspend_state & sr)));
  sh->suspend_state -= sr;
  if (SUSPEND_STATE_NONE != sh->suspend_state)
    return;
  for (struct ServiceListenContext *slc = sh->slc_head;
       NULL != slc;
       slc = slc->next)
  {
    GNUNET_assert (NULL == slc->listen_task);
    slc->listen_task =
      GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                     slc->listen_socket,
                                     &accept_client,
                                     slc);
  }
}
 
 
static void
service_main (void *cls)
{
  struct GNUNET_SERVICE_Handle *sh = cls;
 
  if (GNUNET_SERVICE_OPTION_MANUAL_SHUTDOWN !=
      (sh->options & GNUNET_SERVICE_OPTION_SHUTDOWN_BITMASK))
    GNUNET_SCHEDULER_add_shutdown (&service_shutdown, sh);
  do_resume (sh, SUSPEND_STATE_NONE);
 
  if (-1 != sh->ready_confirm_fd)
  {
    GNUNET_break (1 == write (sh->ready_confirm_fd, ".", 1));
    GNUNET_break (0 == close (sh->ready_confirm_fd));
    sh->ready_confirm_fd = -1;
  }
 
  if (NULL != sh->service_init_cb)
    sh->service_init_cb (sh->cb_cls, sh->cfg, sh);
}
 
 
static enum GNUNET_GenericReturnValue
process_acl4 (struct GNUNET_STRINGS_IPv4NetworkPolicy **ret,
              struct GNUNET_SERVICE_Handle *sh,
              const char *option)
{
  char *opt;
 
  if (! GNUNET_CONFIGURATION_have_value (sh->cfg, sh->service_name, option))
  {
    *ret = NULL;
    return GNUNET_OK;
  }
  GNUNET_break (GNUNET_OK ==
                GNUNET_CONFIGURATION_get_value_string (sh->cfg,
                                                       sh->service_name,
                                                       option,
                                                       &opt));
  if (NULL == (*ret = GNUNET_STRINGS_parse_ipv4_policy (opt)))
  {
    LOG (GNUNET_ERROR_TYPE_WARNING,
         _ ("Could not parse IPv4 network specification `%s' for `%s:%s'\n"),
         opt,
         sh->service_name,
         option);
    GNUNET_free (opt);
    return GNUNET_SYSERR;
  }
  GNUNET_free (opt);
  return GNUNET_OK;
}
 
 
static enum GNUNET_GenericReturnValue
process_acl6 (struct GNUNET_STRINGS_IPv6NetworkPolicy **ret,
              struct GNUNET_SERVICE_Handle *sh,
              const char *option)
{
  char *opt;
 
  if (! GNUNET_CONFIGURATION_have_value (sh->cfg, sh->service_name, option))
  {
    *ret = NULL;
    return GNUNET_OK;
  }
  GNUNET_break (GNUNET_OK ==
                GNUNET_CONFIGURATION_get_value_string (sh->cfg,
                                                       sh->service_name,
                                                       option,
                                                       &opt));
  if (NULL == (*ret = GNUNET_STRINGS_parse_ipv6_policy (opt)))
  {
    LOG (GNUNET_ERROR_TYPE_WARNING,
         _ ("Could not parse IPv6 network specification `%s' for `%s:%s'\n"),
         opt,
         sh->service_name,
         option);
    GNUNET_free (opt);
    return GNUNET_SYSERR;
  }
  GNUNET_free (opt);
  return GNUNET_OK;
}
 
 
static void
add_unixpath (struct sockaddr **saddrs,
              socklen_t *saddrlens,
              const char *unixpath)
{
#ifdef AF_UNIX
  struct sockaddr_un *un;
 
  un = GNUNET_new (struct sockaddr_un);
  un->sun_family = AF_UNIX;
  GNUNET_strlcpy (un->sun_path, unixpath, sizeof(un->sun_path));
#if HAVE_SOCKADDR_UN_SUN_LEN
  un->sun_len = (u_char) sizeof(struct sockaddr_un);
#endif
  *saddrs = (struct sockaddr *) un;
  *saddrlens = sizeof(struct sockaddr_un);
#else
  /* this function should never be called
   * unless AF_UNIX is defined! */
  GNUNET_assert (0);
#endif
}
 
 
static int
get_server_addresses (const char *service_name,
                      const struct GNUNET_CONFIGURATION_Handle *cfg,
                      struct sockaddr ***addrs,
                      socklen_t **addr_lens)
{
  int disablev6;
  struct GNUNET_NETWORK_Handle *desc;
  unsigned long long port;
  char *unixpath;
  struct addrinfo hints;
  struct addrinfo *res;
  struct addrinfo *pos;
  struct addrinfo *next;
  unsigned int i;
  int resi;
  int ret;
  struct sockaddr **saddrs;
  socklen_t *saddrlens;
  char *hostname;
 
  *addrs = NULL;
  *addr_lens = NULL;
  desc = NULL;
  disablev6 = GNUNET_NO;
  if ((GNUNET_NO == GNUNET_NETWORK_test_pf (PF_INET6)) ||
      (GNUNET_YES ==
       GNUNET_CONFIGURATION_get_value_yesno (cfg, service_name, "DISABLEV6")))
    disablev6 = GNUNET_YES;
 
  port = 0;
  if (GNUNET_CONFIGURATION_have_value (cfg, service_name, "PORT"))
  {
    if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (cfg,
                                                            service_name,
                                                            "PORT",
                                                            &port))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Require valid port number for service `%s' in configuration!\n"),
           service_name);
    }
    if (port > 65535)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Require valid port number for service `%s' in configuration!\n"),
           service_name);
      return GNUNET_SYSERR;
    }
  }
 
  if (GNUNET_CONFIGURATION_have_value (cfg, service_name, "BINDTO"))
  {
    GNUNET_break (GNUNET_OK ==
                  GNUNET_CONFIGURATION_get_value_string (cfg,
                                                         service_name,
                                                         "BINDTO",
                                                         &hostname));
  }
  else
    hostname = NULL;
 
  unixpath = NULL;
#ifdef AF_UNIX
  if ((GNUNET_YES ==
       GNUNET_CONFIGURATION_have_value (cfg, service_name, "UNIXPATH")) &&
      (GNUNET_OK == GNUNET_CONFIGURATION_get_value_filename (cfg,
                                                             service_name,
                                                             "UNIXPATH",
                                                             &unixpath)) &&
      (0 < strlen (unixpath)))
  {
    /* probe UNIX support */
    struct sockaddr_un s_un;
 
    if (strlen (unixpath) >= sizeof(s_un.sun_path))
    {
      LOG (GNUNET_ERROR_TYPE_WARNING,
           _ ("UNIXPATH `%s' too long, maximum length is %llu\n"),
           unixpath,
           (unsigned long long) sizeof(s_un.sun_path));
      unixpath = GNUNET_NETWORK_shorten_unixpath (unixpath);
      LOG (GNUNET_ERROR_TYPE_INFO, _ ("Using `%s' instead\n"), unixpath);
    }
    if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (unixpath))
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, "mkdir", unixpath);
  }
  if (NULL != unixpath)
  {
    desc = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0);
    if (NULL == desc)
    {
      if ((ENOBUFS == errno) || (ENOMEM == errno) || (ENFILE == errno) ||
          (EACCES == errno))
      {
        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "socket");
        GNUNET_free (hostname);
        GNUNET_free (unixpath);
        return GNUNET_SYSERR;
      }
      LOG (GNUNET_ERROR_TYPE_INFO,
           _ (
             "Disabling UNIX domain socket support for service `%s', failed to create UNIX domain socket: %s\n"),
           service_name,
           strerror (errno));
      GNUNET_free (unixpath);
      unixpath = NULL;
    }
    else
    {
      GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (desc));
      desc = NULL;
    }
  }
#endif
 
  if ((0 == port) && (NULL == unixpath))
  {
    LOG (GNUNET_ERROR_TYPE_ERROR,
         _ (
           "Have neither PORT nor UNIXPATH for service `%s', but one is required\n"),
         service_name);
    GNUNET_free (hostname);
    return GNUNET_SYSERR;
  }
  if (0 == port)
  {
    saddrs = GNUNET_new_array (2, struct sockaddr *);
    saddrlens = GNUNET_new_array (2, socklen_t);
    add_unixpath (saddrs, saddrlens, unixpath);
    GNUNET_free (unixpath);
    GNUNET_free (hostname);
    *addrs = saddrs;
    *addr_lens = saddrlens;
    return 1;
  }
 
  if (NULL != hostname)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Resolving `%s' since that is where `%s' will bind to.\n",
         hostname,
         service_name);
    memset (&hints, 0, sizeof(struct addrinfo));
    if (disablev6)
      hints.ai_family = AF_INET;
    hints.ai_protocol = IPPROTO_TCP;
    if ((0 != (ret = getaddrinfo (hostname, NULL, &hints, &res))) ||
        (NULL == res))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Failed to resolve `%s': %s\n"),
           hostname,
           gai_strerror (ret));
      GNUNET_free (hostname);
      GNUNET_free (unixpath);
      return GNUNET_SYSERR;
    }
    next = res;
    i = 0;
    while (NULL != (pos = next))
    {
      next = pos->ai_next;
      if ((disablev6) && (pos->ai_family == AF_INET6))
        continue;
      i++;
    }
    if (0 == i)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Failed to find %saddress for `%s'.\n"),
           disablev6 ? "IPv4 " : "",
           hostname);
      freeaddrinfo (res);
      GNUNET_free (hostname);
      GNUNET_free (unixpath);
      return GNUNET_SYSERR;
    }
    resi = i;
    if (NULL != unixpath)
      resi++;
    saddrs = GNUNET_new_array (resi + 1, struct sockaddr *);
    saddrlens = GNUNET_new_array (resi + 1, socklen_t);
    i = 0;
    if (NULL != unixpath)
    {
      add_unixpath (saddrs, saddrlens, unixpath);
      i++;
    }
    next = res;
    while (NULL != (pos = next))
    {
      next = pos->ai_next;
      if ((disablev6) && (AF_INET6 == pos->ai_family))
        continue;
      if ((IPPROTO_TCP != pos->ai_protocol) && (0 != pos->ai_protocol))
        continue;     /* not TCP */
      if ((SOCK_STREAM != pos->ai_socktype) && (0 != pos->ai_socktype))
        continue;     /* huh? */
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Service `%s' will bind to `%s'\n",
           service_name,
           GNUNET_a2s (pos->ai_addr, pos->ai_addrlen));
      if (AF_INET == pos->ai_family)
      {
        GNUNET_assert (sizeof(struct sockaddr_in) == pos->ai_addrlen);
        saddrlens[i] = pos->ai_addrlen;
        saddrs[i] = GNUNET_malloc (saddrlens[i]);
        GNUNET_memcpy (saddrs[i], pos->ai_addr, saddrlens[i]);
        ((struct sockaddr_in *) saddrs[i])->sin_port = htons (port);
      }
      else
      {
        GNUNET_assert (AF_INET6 == pos->ai_family);
        GNUNET_assert (sizeof(struct sockaddr_in6) == pos->ai_addrlen);
        saddrlens[i] = pos->ai_addrlen;
        saddrs[i] = GNUNET_malloc (saddrlens[i]);
        GNUNET_memcpy (saddrs[i], pos->ai_addr, saddrlens[i]);
        ((struct sockaddr_in6 *) saddrs[i])->sin6_port = htons (port);
      }
      i++;
    }
    GNUNET_free (hostname);
    freeaddrinfo (res);
    resi = i;
  }
  else
  {
    /* will bind against everything, just set port */
    if (disablev6)
    {
      /* V4-only */
      resi = 1;
      if (NULL != unixpath)
        resi++;
      i = 0;
      saddrs = GNUNET_new_array (resi + 1, struct sockaddr *);
      saddrlens = GNUNET_new_array (resi + 1, socklen_t);
      if (NULL != unixpath)
      {
        add_unixpath (saddrs, saddrlens, unixpath);
        i++;
      }
      saddrlens[i] = sizeof(struct sockaddr_in);
      saddrs[i] = GNUNET_malloc (saddrlens[i]);
#if HAVE_SOCKADDR_IN_SIN_LEN
      ((struct sockaddr_in *) saddrs[i])->sin_len = saddrlens[i];
#endif
      ((struct sockaddr_in *) saddrs[i])->sin_family = AF_INET;
      ((struct sockaddr_in *) saddrs[i])->sin_port = htons (port);
    }
    else
    {
      /* dual stack */
      resi = 2;
      if (NULL != unixpath)
        resi++;
      saddrs = GNUNET_new_array (resi + 1, struct sockaddr *);
      saddrlens = GNUNET_new_array (resi + 1, socklen_t);
      i = 0;
      if (NULL != unixpath)
      {
        add_unixpath (saddrs, saddrlens, unixpath);
        i++;
      }
      saddrlens[i] = sizeof(struct sockaddr_in6);
      saddrs[i] = GNUNET_malloc (saddrlens[i]);
#if HAVE_SOCKADDR_IN_SIN_LEN
      ((struct sockaddr_in6 *) saddrs[i])->sin6_len = saddrlens[0];
#endif
      ((struct sockaddr_in6 *) saddrs[i])->sin6_family = AF_INET6;
      ((struct sockaddr_in6 *) saddrs[i])->sin6_port = htons (port);
      i++;
      saddrlens[i] = sizeof(struct sockaddr_in);
      saddrs[i] = GNUNET_malloc (saddrlens[i]);
#if HAVE_SOCKADDR_IN_SIN_LEN
      ((struct sockaddr_in *) saddrs[i])->sin_len = saddrlens[1];
#endif
      ((struct sockaddr_in *) saddrs[i])->sin_family = AF_INET;
      ((struct sockaddr_in *) saddrs[i])->sin_port = htons (port);
    }
  }
  GNUNET_free (unixpath);
  *addrs = saddrs;
  *addr_lens = saddrlens;
  return resi;
}
 
 
static struct GNUNET_NETWORK_Handle *
open_listen_socket (const struct sockaddr *server_addr,
                    socklen_t socklen)
{
  struct GNUNET_NETWORK_Handle *sock;
  uint16_t port;
  int eno;
 
  switch (server_addr->sa_family)
  {
  case AF_INET:
    port = ntohs (((const struct sockaddr_in *) server_addr)->sin_port);
    break;
  case AF_INET6:
    port = ntohs (((const struct sockaddr_in6 *) server_addr)->sin6_port);
    break;
  case AF_UNIX:
    port = 0;
    break;
  default:
    GNUNET_break (0);
    port = 0;
    break;
  }
  sock = GNUNET_NETWORK_socket_create (server_addr->sa_family,
                                       SOCK_STREAM,
                                       0);
  if (NULL == sock)
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR,
                  "socket");
    errno = 0;
    return NULL;
  }
  /* bind the socket */
  if (GNUNET_OK !=
      GNUNET_NETWORK_socket_bind (sock,
                                  server_addr,
                                  socklen))
  {
    eno = errno;
    if (EADDRINUSE != errno)
    {
      /* we don't log 'EADDRINUSE' here since an IPv4 bind may
       * fail if we already took the port on IPv6; if both IPv4 and
       * IPv6 binds fail, then our caller will log using the
       * errno preserved in 'eno' */
      if (0 != port)
        LOG (GNUNET_ERROR_TYPE_ERROR,
             _ ("`%s' failed for port %d (%s).\n"),
             "bind",
             port,
             (AF_INET == server_addr->sa_family) ? "IPv4" : "IPv6");
      else
        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "bind");
      eno = 0;
    }
    else
    {
      if (0 != port)
        LOG (GNUNET_ERROR_TYPE_WARNING,
             _ ("`%s' failed for port %d (%s): address already in use\n"),
             "bind",
             port,
             (AF_INET == server_addr->sa_family) ? "IPv4" : "IPv6");
      else if (AF_UNIX == server_addr->sa_family)
      {
        LOG (GNUNET_ERROR_TYPE_WARNING,
             _ ("`%s' failed for `%s': address already in use\n"),
             "bind",
             GNUNET_a2s (server_addr, socklen));
      }
    }
    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
    errno = eno;
    return NULL;
  }
  if (GNUNET_OK != GNUNET_NETWORK_socket_listen (sock, 5))
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "listen");
    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
    errno = 0;
    return NULL;
  }
  if (0 != port)
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Server starts to listen on port %u.\n",
         port);
  return sock;
}
 
 
static enum GNUNET_GenericReturnValue
setup_service (struct GNUNET_SERVICE_Handle *sh)
{
  int tolerant;
  struct GNUNET_NETWORK_Handle **csocks = NULL;
  struct GNUNET_NETWORK_Handle **lsocks;
  const char *nfds;
  unsigned int cnt;
  int flags;
  char dummy[2];
 
  if (GNUNET_CONFIGURATION_have_value (sh->cfg,
                                       sh->service_name,
                                       "TOLERANT"))
  {
    if (GNUNET_SYSERR ==
        (tolerant = GNUNET_CONFIGURATION_get_value_yesno (sh->cfg,
                                                          sh->service_name,
                                                          "TOLERANT")))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Specified value for `%s' of service `%s' is invalid\n"),
           "TOLERANT",
           sh->service_name);
      return GNUNET_SYSERR;
    }
  }
  else
    tolerant = GNUNET_NO;
 
  lsocks = NULL;
  errno = 0;
  if ( (NULL != (nfds = getenv ("LISTEN_FDS"))) &&
       (1 == sscanf (nfds, "%u%1s", &cnt, dummy)) && (cnt > 0) &&
      (cnt < FD_SETSIZE) && (cnt + 4 < FD_SETSIZE))
  {
    lsocks = GNUNET_new_array (cnt + 1, struct GNUNET_NETWORK_Handle *);
    while (0 < cnt--)
    {
      flags = fcntl (3 + cnt, F_GETFD);
      if ((flags < 0) || (0 != (flags & FD_CLOEXEC)) ||
          (NULL == (lsocks[cnt] = GNUNET_NETWORK_socket_box_native (3 + cnt))))
      {
        LOG (GNUNET_ERROR_TYPE_ERROR,
             _ (
               "Could not access pre-bound socket %u, will try to bind myself\n"),
             (unsigned int) 3 + cnt);
        cnt++;
        while (NULL != lsocks[cnt])
          GNUNET_break (GNUNET_OK ==
                        GNUNET_NETWORK_socket_close (lsocks[cnt++]));
        GNUNET_free (lsocks);
        lsocks = NULL;
        break;
      }
    }
    unsetenv ("LISTEN_FDS");
  }
  if ( (0 != (GNUNET_SERVICE_OPTION_CLOSE_LSOCKS & sh->options)) &&
       (NULL != lsocks) )
  {
    csocks = lsocks;
    lsocks = NULL;
  }
 
  if (NULL != lsocks)
  {
    /* listen only on inherited sockets if we have any */
    for (struct GNUNET_NETWORK_Handle **ls = lsocks; NULL != *ls; ls++)
    {
      struct ServiceListenContext *slc;
 
      slc = GNUNET_new (struct ServiceListenContext);
      slc->sh = sh;
      slc->listen_socket = *ls;
      GNUNET_CONTAINER_DLL_insert (sh->slc_head,
                                   sh->slc_tail,
                                   slc);
    }
    GNUNET_free (lsocks);
  }
  else
  {
    struct sockaddr **addrs;
    socklen_t *addrlens;
    int num;
 
    num = get_server_addresses (sh->service_name, sh->cfg, &addrs, &addrlens);
    if (GNUNET_SYSERR == num)
      return GNUNET_SYSERR;
 
    for (int i = 0; i < num; i++)
    {
      struct ServiceListenContext *slc;
 
      slc = GNUNET_new (struct ServiceListenContext);
      slc->sh = sh;
      slc->listen_socket = open_listen_socket (addrs[i],
                                               addrlens[i]);
      GNUNET_free (addrs[i]);
      if (NULL == slc->listen_socket)
      {
        GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
        GNUNET_free (slc);
        continue;
      }
      GNUNET_CONTAINER_DLL_insert (sh->slc_head,
                                   sh->slc_tail,
                                   slc);
    }
    GNUNET_free (addrlens);
    GNUNET_free (addrs);
    if ((0 != num) && (NULL == sh->slc_head))
    {
      /* All attempts to bind failed, hard failure */
      GNUNET_log (
        GNUNET_ERROR_TYPE_ERROR,
        _ (
          "Could not bind to any of the ports I was supposed to, refusing to run!\n"));
      GNUNET_free (csocks);
      return GNUNET_SYSERR;
    }
  }
  if (NULL != csocks)
  {
    /* close inherited sockets to signal parent that we are ready */
    for (struct GNUNET_NETWORK_Handle **ls = csocks; NULL != *ls; ls++)
      GNUNET_NETWORK_socket_close (*ls);
    GNUNET_free (csocks);
  }
  sh->require_found = (GNUNET_NO == tolerant);
  sh->match_uid = GNUNET_CONFIGURATION_get_value_yesno (sh->cfg,
                                                        sh->service_name,
                                                        "UNIX_MATCH_UID");
  sh->match_gid = GNUNET_CONFIGURATION_get_value_yesno (sh->cfg,
                                                        sh->service_name,
                                                        "UNIX_MATCH_GID");
  process_acl4 (&sh->v4_denied, sh, "REJECT_FROM");
  process_acl4 (&sh->v4_allowed, sh, "ACCEPT_FROM");
  process_acl6 (&sh->v6_denied, sh, "REJECT_FROM6");
  process_acl6 (&sh->v6_allowed, sh, "ACCEPT_FROM6");
  return GNUNET_OK;
}
 
 
static char *
get_user_name (struct GNUNET_SERVICE_Handle *sh)
{
  char *un;
 
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (sh->cfg,
                                               sh->service_name,
                                               "USERNAME",
                                               &un))
    return NULL;
  return un;
}
 
 
static enum GNUNET_GenericReturnValue
set_user_id (struct GNUNET_SERVICE_Handle *sh)
{
  char *user;
  struct passwd *pws;
 
  if (NULL == (user = get_user_name (sh)))
    return GNUNET_OK; /* keep */
  errno = 0;
  pws = getpwnam (user);
  if (NULL == pws)
  {
    LOG (GNUNET_ERROR_TYPE_ERROR,
         _ ("Cannot obtain information about user `%s': %s\n"),
         user,
         errno == 0 ? _ ("No such user") : strerror (errno));
    GNUNET_free (user);
    return GNUNET_SYSERR;
  }
  if ((0 != setgid (pws->pw_gid)) || (0 != setegid (pws->pw_gid)) ||
#if HAVE_INITGROUPS
      (0 != initgroups (user, pws->pw_gid)) ||
#endif
      (0 != setuid (pws->pw_uid)) ||
      (0 != seteuid (pws->pw_uid)))
  {
    if ((0 != setregid (pws->pw_gid, pws->pw_gid)) ||
        (0 != setreuid (pws->pw_uid, pws->pw_uid)))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           _ ("Cannot change user/group to `%s': %s\n"),
           user,
           strerror (errno));
      GNUNET_free (user);
      return GNUNET_SYSERR;
    }
  }
 
  GNUNET_free (user);
  return GNUNET_OK;
}
 
 
static char *
get_pid_file_name (struct GNUNET_SERVICE_Handle *sh)
{
  char *pif;
 
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (sh->cfg,
                                               sh->service_name,
                                               "PIDFILE",
                                               &pif))
    return NULL;
  return pif;
}
 
 
static void
pid_file_delete (struct GNUNET_SERVICE_Handle *sh)
{
  char *pif = get_pid_file_name (sh);
 
  if (NULL == pif)
    return; /* no PID file */
  if (0 != unlink (pif))
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "unlink",
                       pif);
  GNUNET_free (pif);
}
 
 
static enum GNUNET_GenericReturnValue
detach_terminal (struct GNUNET_SERVICE_Handle *sh)
{
  pid_t pid;
  int nullfd;
  int filedes[2];
 
  if (0 != pipe (filedes))
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR,
                  "pipe");
    return GNUNET_SYSERR;
  }
  pid = fork ();
  if (pid < 0)
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR,
                  "fork");
    return GNUNET_SYSERR;
  }
  if (0 != pid)
  {
    /* Parent */
    char c;
 
    GNUNET_break (0 == close (filedes[1]));
    c = 'X';
    if (1 != read (filedes[0], &c, sizeof(char)))
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING,
                    "read");
    fflush (stdout);
    switch (c)
    {
    case '.':
      exit (0);
 
    case 'I':
      LOG (GNUNET_ERROR_TYPE_INFO,
           _ ("Service process failed to initialize\n"));
      break;
 
    case 'S':
      LOG (GNUNET_ERROR_TYPE_INFO,
           _ ("Service process could not initialize server function\n"));
      break;
 
    case 'X':
      LOG (GNUNET_ERROR_TYPE_INFO,
           _ ("Service process failed to report status\n"));
      break;
    }
    exit (1);  /* child reported error */
  }
  GNUNET_break (0 == close (0));
  GNUNET_break (0 == close (1));
  GNUNET_break (0 == close (filedes[0]));
  nullfd = open ("/dev/null", O_RDWR | O_APPEND);
  if (nullfd < 0)
    return GNUNET_SYSERR;
  /* set stdin/stdout to /dev/null */
  if ((dup2 (nullfd, 0) < 0) || (dup2 (nullfd, 1) < 0))
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "dup2");
    (void) close (nullfd);
    return GNUNET_SYSERR;
  }
  (void) close (nullfd);
  /* Detach from controlling terminal */
  pid = setsid ();
  if (-1 == pid)
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR,
                  "setsid");
  sh->ready_confirm_fd = filedes[1];
 
  return GNUNET_OK;
}
 
 
static void
teardown_service (struct GNUNET_SERVICE_Handle *sh)
{
  struct ServiceListenContext *slc;
 
  GNUNET_free (sh->v4_denied);
  GNUNET_free (sh->v6_denied);
  GNUNET_free (sh->v4_allowed);
  GNUNET_free (sh->v6_allowed);
  while (NULL != (slc = sh->slc_head))
  {
    GNUNET_CONTAINER_DLL_remove (sh->slc_head,
                                 sh->slc_tail,
                                 slc);
    if (NULL != slc->listen_task)
      GNUNET_SCHEDULER_cancel (slc->listen_task);
    GNUNET_break (GNUNET_OK ==
                  GNUNET_NETWORK_socket_close (slc->listen_socket));
    GNUNET_free (slc);
  }
}
 
 
static void
return_agpl (void *cls,
             const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_SERVICE_Client *client = cls;
  struct GNUNET_MQ_Handle *mq;
  struct GNUNET_MQ_Envelope *env;
  struct GNUNET_MessageHeader *res;
  size_t slen;
  const struct GNUNET_OS_ProjectData *pd = GNUNET_OS_project_data_get ();
 
  (void) msg;
  slen = strlen (pd->agpl_url) + 1;
  env = GNUNET_MQ_msg_extra (res,
                             GNUNET_MESSAGE_TYPE_RESPONSE_AGPL, slen);
  memcpy (&res[1],
          GNUNET_AGPL_URL,
          slen);
  mq = GNUNET_SERVICE_client_get_mq (client);
  GNUNET_MQ_send (mq, env);
  GNUNET_SERVICE_client_continue (client);
}
 
 
struct GNUNET_SERVICE_Handle *
GNUNET_SERVICE_start (const char *service_name,
                      const struct GNUNET_CONFIGURATION_Handle *cfg,
                      GNUNET_SERVICE_ConnectHandler connect_cb,
                      GNUNET_SERVICE_DisconnectHandler disconnect_cb,
                      void *cls,
                      const struct GNUNET_MQ_MessageHandler *handlers)
{
  struct GNUNET_SERVICE_Handle *sh;
 
  sh = GNUNET_new (struct GNUNET_SERVICE_Handle);
  sh->service_name = service_name;
  sh->cfg = cfg;
  sh->connect_cb = connect_cb;
  sh->disconnect_cb = disconnect_cb;
  sh->cb_cls = cls;
  sh->handlers = GNUNET_MQ_copy_handlers2 (handlers,
                                           &return_agpl,
                                           NULL);
  if (GNUNET_OK != setup_service (sh))
  {
    GNUNET_free (sh->handlers);
    GNUNET_free (sh);
    return NULL;
  }
  do_resume (sh,
             SUSPEND_STATE_NONE);
  return sh;
}
 
 
static void
finish_client_drop (void *cls)
{
  struct GNUNET_SERVICE_Client *c = cls;
  struct GNUNET_SERVICE_Handle *sh = c->sh;
 
  c->drop_task = NULL;
  GNUNET_CONTAINER_DLL_remove (sh->clients_head,
                               sh->clients_tail,
                               c);
  GNUNET_assert (NULL == c->send_task);
  GNUNET_assert (NULL == c->recv_task);
  GNUNET_assert (NULL == c->warn_task);
  GNUNET_MST_destroy (c->mst);
  GNUNET_MQ_destroy (c->mq);
  if (! c->persist)
  {
    GNUNET_break (GNUNET_OK ==
                  GNUNET_NETWORK_socket_close (c->sock));
    if ((0 != (SUSPEND_STATE_EMFILE & sh->suspend_state)) &&
        (0 == (SUSPEND_STATE_SHUTDOWN & sh->suspend_state)))
      do_resume (sh,
                 SUSPEND_STATE_EMFILE);
  }
  else
  {
    GNUNET_NETWORK_socket_free_memory_only_ (c->sock);
  }
  GNUNET_free (c);
  if ((0 != (SUSPEND_STATE_SHUTDOWN & sh->suspend_state)) &&
      (! have_non_monitor_clients (sh)))
    GNUNET_SERVICE_shutdown (sh);
}
 
 
void
GNUNET_SERVICE_stop (struct GNUNET_SERVICE_Handle *srv)
{
  struct GNUNET_SERVICE_Client *client;
 
  GNUNET_SERVICE_suspend (srv);
  while (NULL != (client = srv->clients_head))
  {
    if (NULL == client->drop_task)
      GNUNET_SERVICE_client_drop (client);
    GNUNET_SCHEDULER_cancel (client->drop_task);
    finish_client_drop (client);
  }
  teardown_service (srv);
  GNUNET_free (srv->handlers);
  GNUNET_free (srv);
}
 
 
int
GNUNET_SERVICE_run_ (int argc,
                     char *const *argv,
                     const char *service_name,
                     enum GNUNET_SERVICE_Options options,
                     GNUNET_SERVICE_InitCallback service_init_cb,
                     GNUNET_SERVICE_ConnectHandler connect_cb,
                     GNUNET_SERVICE_DisconnectHandler disconnect_cb,
                     void *cls,
                     const struct GNUNET_MQ_MessageHandler *handlers)
{
  struct GNUNET_SERVICE_Handle sh;
 
#if ENABLE_NLS
  char *path;
#endif
  char *cfg_filename;
  char *opt_cfg_filename;
  char *loglev;
  const char *xdg;
  char *logfile;
  int do_daemonize;
  unsigned long long skew_offset;
  unsigned long long skew_variance;
  long long clock_offset;
  struct GNUNET_CONFIGURATION_Handle *cfg;
  int ret;
  int err;
  const struct GNUNET_OS_ProjectData *pd = GNUNET_OS_project_data_get ();
  struct GNUNET_GETOPT_CommandLineOption service_options[] = {
    GNUNET_GETOPT_option_cfgfile (&opt_cfg_filename),
    GNUNET_GETOPT_option_flag ('d',
                               "daemonize",
                               gettext_noop (
                                 "do daemonize (detach from terminal)"),
                               &do_daemonize),
    GNUNET_GETOPT_option_help (NULL),
    GNUNET_GETOPT_option_loglevel (&loglev),
    GNUNET_GETOPT_option_logfile (&logfile),
    GNUNET_GETOPT_option_version (pd->version),
    GNUNET_GETOPT_OPTION_END
  };
 
  err = 1;
  memset (&sh, 0, sizeof(sh));
  xdg = getenv ("XDG_CONFIG_HOME");
  if (NULL != xdg)
    GNUNET_asprintf (&cfg_filename,
                     "%s%s%s",
                     xdg,
                     DIR_SEPARATOR_STR,
                     pd->config_file);
  else
    cfg_filename = GNUNET_strdup (pd->user_config_file);
  sh.ready_confirm_fd = -1;
  sh.options = options;
  sh.cfg = cfg = GNUNET_CONFIGURATION_create ();
  sh.service_init_cb = service_init_cb;
  sh.connect_cb = connect_cb;
  sh.disconnect_cb = disconnect_cb;
  sh.cb_cls = cls;
  sh.handlers = (NULL == pd->agpl_url)
                ? GNUNET_MQ_copy_handlers (handlers)
                : GNUNET_MQ_copy_handlers2 (handlers, &return_agpl, NULL);
  sh.service_name = service_name;
  /* setup subsystems */
  loglev = NULL;
  logfile = NULL;
  opt_cfg_filename = NULL;
  do_daemonize = 0;
#if ENABLE_NLS
  if (NULL != pd->gettext_domain)
  {
    setlocale (LC_ALL, "");
    path = (NULL == pd->gettext_path) ?
           GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LOCALEDIR) :
           GNUNET_strdup (pd->gettext_path);
    if (NULL != path)
    {
      bindtextdomain (pd->gettext_domain, path);
      GNUNET_free (path);
    }
    textdomain (pd->gettext_domain);
  }
#endif
  ret = GNUNET_GETOPT_run (service_name,
                           service_options,
                           argc,
                           argv);
  if (GNUNET_SYSERR == ret)
    goto shutdown;
  if (GNUNET_NO == ret)
  {
    err = 0;
    goto shutdown;
  }
  if (GNUNET_OK != GNUNET_log_setup (service_name,
                                     loglev,
                                     logfile))
  {
    GNUNET_break (0);
    goto shutdown;
  }
  if (NULL != opt_cfg_filename)
  {
    if ((GNUNET_YES != GNUNET_DISK_file_test (opt_cfg_filename)) ||
        (GNUNET_SYSERR == GNUNET_CONFIGURATION_load (cfg, opt_cfg_filename)))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  _ ("Malformed configuration file `%s', exit ...\n"),
                  opt_cfg_filename);
      goto shutdown;
    }
  }
  else
  {
    if (GNUNET_YES ==
        GNUNET_DISK_file_test (cfg_filename))
    {
      if (GNUNET_SYSERR ==
          GNUNET_CONFIGURATION_load (cfg,
                                     cfg_filename))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    _ ("Malformed configuration file `%s', exit ...\n"),
                    cfg_filename);
        goto shutdown;
      }
    }
    else
    {
      if (GNUNET_SYSERR ==
          GNUNET_CONFIGURATION_load (cfg,
                                     NULL))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    _ ("Malformed configuration, exit ...\n"));
        goto shutdown;
      }
    }
  }
  if (GNUNET_OK != setup_service (&sh))
    goto shutdown;
  if ( (1 == do_daemonize) &&
       (GNUNET_OK != detach_terminal (&sh)) )
  {
    GNUNET_break (0);
    goto shutdown;
  }
  if (GNUNET_OK != set_user_id (&sh))
    goto shutdown;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Service `%s' runs with configuration from `%s'\n",
       service_name,
       (NULL != opt_cfg_filename) ? opt_cfg_filename : cfg_filename);
  if ( (GNUNET_OK ==
        GNUNET_CONFIGURATION_get_value_number (sh.cfg,
                                               "TESTING",
                                               "SKEW_OFFSET",
                                               &skew_offset)) &&
       (GNUNET_OK ==
        GNUNET_CONFIGURATION_get_value_number (sh.cfg,
                                               "TESTING",
                                               "SKEW_VARIANCE",
                                               &skew_variance)) )
  {
    clock_offset = skew_offset - skew_variance;
    GNUNET_TIME_set_offset (clock_offset);
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Skewing clock by %lld ms\n",
         (long long) clock_offset);
  }
  GNUNET_RESOLVER_connect (sh.cfg);
 
  /* actually run service */
  err = 0;
  GNUNET_SCHEDULER_run (&service_main, &sh);
  /* shutdown */
  if (1 == do_daemonize)
    pid_file_delete (&sh);
 
shutdown:
  if (-1 != sh.ready_confirm_fd)
  {
    if (1 != write (sh.ready_confirm_fd, err ? "I" : "S", 1))
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "write");
    GNUNET_break (0 == close (sh.ready_confirm_fd));
  }
#if HAVE_MALLINFO2
  {
    char *counter;
 
    if ( (GNUNET_YES ==
          GNUNET_CONFIGURATION_have_value (sh.cfg,
                                           service_name,
                                           "GAUGER_HEAP")) &&
         (GNUNET_OK ==
          GNUNET_CONFIGURATION_get_value_string (sh.cfg,
                                                 service_name,
                                                 "GAUGER_HEAP",
                                                 &counter)))
    {
      struct mallinfo2 mi;
 
      mi = mallinfo2 ();
      GAUGER (service_name,
              counter,
              mi.usmblks,
              "blocks");
      GNUNET_free (counter);
    }
  }
#endif
  teardown_service (&sh);
  GNUNET_free (sh.handlers);
  GNUNET_SPEEDUP_stop_ ();
  GNUNET_CONFIGURATION_destroy (cfg);
  GNUNET_free (logfile);
  GNUNET_free (loglev);
  GNUNET_free (cfg_filename);
  GNUNET_free (opt_cfg_filename);
 
  return err ? GNUNET_SYSERR : 0;
}
 
 
struct ServiceHandleList
{
  /* DLL */
  struct ServiceHandleList *prev;
 
  /* DLL */
  struct ServiceHandleList *next;
 
  /* Handle to the service to launch */
  struct GNUNET_SERVICE_Handle *sh;
};
 
/* The service list */
static struct ServiceHandleList *hll_head;
 
/* The service list */
static struct ServiceHandleList *hll_tail;
 
 
int
GNUNET_SERVICE_register_ (const char *service_name,
                          enum GNUNET_SERVICE_Options options,
                          GNUNET_SERVICE_InitCallback service_init_cb,
                          GNUNET_SERVICE_ConnectHandler connect_cb,
                          GNUNET_SERVICE_DisconnectHandler disconnect_cb,
                          void *cls,
                          const struct GNUNET_MQ_MessageHandler *handlers)
{
  struct ServiceHandleList *hle;
  struct GNUNET_SERVICE_Handle *sh = GNUNET_new (struct GNUNET_SERVICE_Handle);
  const struct GNUNET_OS_ProjectData *pd = GNUNET_OS_project_data_get ();
 
  sh->ready_confirm_fd = -1;
  sh->options = options;
  sh->service_init_cb = service_init_cb;
  sh->connect_cb = connect_cb;
  sh->disconnect_cb = disconnect_cb;
  sh->cb_cls = cls;
  sh->handlers = (NULL == pd->agpl_url)
                ? GNUNET_MQ_copy_handlers (handlers)
                : GNUNET_MQ_copy_handlers2 (handlers, &return_agpl, NULL);
  sh->service_name = service_name;
  hle = GNUNET_new (struct ServiceHandleList);
  hle->sh = sh;
  GNUNET_CONTAINER_DLL_insert (hll_head,
                               hll_tail,
                               hle);
  return 0;
}
 
 
static void
do_registered_services_shutdown (void *cls)
{
  while (NULL != hll_head)
  {
    struct ServiceHandleList *shl = hll_head;
    struct GNUNET_SERVICE_Handle *sh = shl->sh;
 
    GNUNET_CONTAINER_DLL_remove (hll_head,
                                 hll_tail,
                                 shl);
    GNUNET_free (shl);
    if (-1 != sh->ready_confirm_fd)
    {
      if (1 != write (sh->ready_confirm_fd, "S", 1))
        LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING,
                      "write");
      GNUNET_break (0 ==
                    close (sh->ready_confirm_fd));
    }
    teardown_service (sh);
    GNUNET_free (sh->handlers);
    GNUNET_free (sh);
  }
}
 
 
static void
launch_registered_services (void *cls)
{
  struct GNUNET_CONFIGURATION_Handle *cfg = cls;
 
  for (struct ServiceHandleList *shl = hll_head;
       NULL != shl;
       shl = shl->next)
  {
    shl->sh->cfg = cfg;
    if (GNUNET_OK != setup_service (shl->sh))
      continue;
    if (GNUNET_OK != set_user_id (shl->sh))
      continue;
    GNUNET_SCHEDULER_add_now (&service_main,
                              shl->sh);
  }
  GNUNET_SCHEDULER_add_shutdown (&do_registered_services_shutdown,
                                 NULL);
}
 
 
void
GNUNET_SERVICE_main (int argc,
                     char *const *argv)
{
  char *cfg_filename;
  char *opt_cfg_filename;
  char *logfile;
  char *loglev;
  const char *xdg;
  int do_daemonize;
  int ret;
  struct GNUNET_CONFIGURATION_Handle *cfg;
  const struct GNUNET_OS_ProjectData *pd = GNUNET_OS_project_data_get ();
  struct GNUNET_GETOPT_CommandLineOption service_options[] = {
    GNUNET_GETOPT_option_cfgfile (&opt_cfg_filename),
    GNUNET_GETOPT_option_flag ('d',
                               "daemonize",
                               gettext_noop (
                                 "do daemonize (detach from terminal)"),
                               &do_daemonize),
    GNUNET_GETOPT_option_help (NULL),
    GNUNET_GETOPT_option_loglevel (&loglev),
    GNUNET_GETOPT_option_logfile (&logfile),
    GNUNET_GETOPT_option_version (pd->version),
    GNUNET_GETOPT_OPTION_END
  };
  
  xdg = getenv ("XDG_CONFIG_HOME");
  if (NULL != xdg)
    GNUNET_asprintf (&cfg_filename,
                     "%s%s%s",
                     xdg,
                     DIR_SEPARATOR_STR,
                     pd->config_file);
  else
    cfg_filename = GNUNET_strdup (pd->user_config_file);
  cfg = GNUNET_CONFIGURATION_create ();
  // FIXME we need to set this up for each service!
  ret = GNUNET_GETOPT_run ("libgnunet",
                           service_options,
                           argc,
                           argv);
  if (GNUNET_SYSERR == ret)
    goto shutdown;
  if (GNUNET_NO == ret)
  {
    goto shutdown;
  }
  // FIXME we need to set this up for each service!
  // NOTE: that was not the idea. What are you proposing? -CG
  if (GNUNET_OK !=
      GNUNET_log_setup ("libgnunet",
                        loglev,
                        logfile))
  {
    GNUNET_break (0);
    goto shutdown;
  }
  if (NULL != opt_cfg_filename)
  {
    if ( (GNUNET_YES !=
          GNUNET_DISK_file_test (opt_cfg_filename)) ||
         (GNUNET_SYSERR ==
          GNUNET_CONFIGURATION_load (cfg,
                                     opt_cfg_filename)) )
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  _ ("Malformed configuration file `%s', exit ...\n"),
                  opt_cfg_filename);
      goto shutdown;
    }
  }
  else
  {
    if (GNUNET_YES ==
        GNUNET_DISK_file_test (cfg_filename))
    {
      if (GNUNET_SYSERR ==
          GNUNET_CONFIGURATION_load (cfg,
                                     cfg_filename))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    _ ("Malformed configuration file `%s', exit ...\n"),
                    cfg_filename);
        GNUNET_free (cfg_filename);
        return;
      }
    }
    else
    {
      if (GNUNET_SYSERR ==
          GNUNET_CONFIGURATION_load (cfg,
                                     NULL))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    _ ("Malformed configuration, exit ...\n"));
        GNUNET_free (cfg_filename);
        return;
      }
    }
  }
  GNUNET_RESOLVER_connect (cfg);
 
  GNUNET_SCHEDULER_run (&launch_registered_services,
                        cfg);
shutdown:
  GNUNET_SPEEDUP_stop_ ();
  GNUNET_CONFIGURATION_destroy (cfg);
  GNUNET_free (logfile);
  GNUNET_free (loglev);
  GNUNET_free (cfg_filename);
  GNUNET_free (opt_cfg_filename);
}
 
 
void
GNUNET_SERVICE_suspend (struct GNUNET_SERVICE_Handle *sh)
{
  do_suspend (sh,
              SUSPEND_STATE_APP);
}
 
 
void
GNUNET_SERVICE_resume (struct GNUNET_SERVICE_Handle *sh)
{
  do_resume (sh,
             SUSPEND_STATE_APP);
}
 
 
static void
resume_client_receive (void *cls)
{
  struct GNUNET_SERVICE_Client *c = cls;
  int ret;
 
  c->recv_task = NULL;
  /* first, check if there is still something in the buffer */
  ret = GNUNET_MST_next (c->mst,
                         GNUNET_YES);
  if (GNUNET_SYSERR == ret)
  {
    if (NULL == c->drop_task)
      GNUNET_SERVICE_client_drop (c);
    return;
  }
  if (GNUNET_NO == ret)
    return; /* done processing, wait for more later */
  GNUNET_assert (GNUNET_OK == ret);
  if (c->needs_continue)
    return; /* #GNUNET_MST_next() did give a message to the client */
  /* need to receive more data from the network first */
  if (NULL != c->recv_task)
    return;
  c->recv_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                                c->sock,
                                                &service_client_recv,
                                                c);
}
 
 
void
GNUNET_SERVICE_client_continue (struct GNUNET_SERVICE_Client *c)
{
  GNUNET_assert (NULL == c->drop_task);
  GNUNET_assert (c->needs_continue);
  GNUNET_assert (NULL == c->recv_task);
  c->needs_continue = false;
  if (NULL != c->warn_task)
  {
    GNUNET_SCHEDULER_cancel (c->warn_task);
    c->warn_task = NULL;
  }
  c->recv_task = GNUNET_SCHEDULER_add_now (&resume_client_receive,
                                           c);
}
 
 
void
GNUNET_SERVICE_client_disable_continue_warning (struct GNUNET_SERVICE_Client *c)
{
  GNUNET_break (NULL != c->warn_task);
  if (NULL != c->warn_task)
  {
    GNUNET_SCHEDULER_cancel (c->warn_task);
    c->warn_task = NULL;
  }
}
 
 
void
GNUNET_SERVICE_client_drop (struct GNUNET_SERVICE_Client *c)
{
  struct GNUNET_SERVICE_Handle *sh = c->sh;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Client dropped: %p (MQ: %p)\n",
              c,
              c->mq);
#if EXECINFO
  {
    void *backtrace_array[MAX_TRACE_DEPTH];
    int num_backtrace_strings = backtrace (backtrace_array,
                                           MAX_TRACE_DEPTH);
    char **backtrace_strings =
      backtrace_symbols (backtrace_array,
                         t->num_backtrace_strings);
    for (unsigned int i = 0; i < num_backtrace_strings; i++)
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "client drop trace %u: %s\n",
           i,
           backtrace_strings[i]);
  }
#endif
  GNUNET_assert (NULL == c->drop_task);
  if (NULL != sh->disconnect_cb)
    sh->disconnect_cb (sh->cb_cls,
                       c,
                       c->user_context);
  if (NULL != c->warn_task)
  {
    GNUNET_SCHEDULER_cancel (c->warn_task);
    c->warn_task = NULL;
  }
  if (NULL != c->recv_task)
  {
    GNUNET_SCHEDULER_cancel (c->recv_task);
    c->recv_task = NULL;
  }
  if (NULL != c->send_task)
  {
    GNUNET_SCHEDULER_cancel (c->send_task);
    c->send_task = NULL;
  }
  c->drop_task = GNUNET_SCHEDULER_add_now (&finish_client_drop,
                                           c);
}
 
 
void
GNUNET_SERVICE_shutdown (struct GNUNET_SERVICE_Handle *sh)
{
  if (0 == (sh->suspend_state & SUSPEND_STATE_SHUTDOWN))
    do_suspend (sh,
                SUSPEND_STATE_SHUTDOWN);
  for (struct GNUNET_SERVICE_Client *client = sh->clients_head;
       NULL != client;
       client = client->next)
  {
    if (NULL == client->drop_task)
      GNUNET_SERVICE_client_drop (client);
  }
}
 
 
void
GNUNET_SERVICE_client_mark_monitor (struct GNUNET_SERVICE_Client *c)
{
  c->is_monitor = true;
  if (((0 != (SUSPEND_STATE_SHUTDOWN & c->sh->suspend_state)) &&
       (! have_non_monitor_clients (c->sh))))
    GNUNET_SERVICE_shutdown (c->sh);
}
 
 
void
GNUNET_SERVICE_client_persist (struct GNUNET_SERVICE_Client *c)
{
  c->persist = true;
}
 
 
struct GNUNET_MQ_Handle *
GNUNET_SERVICE_client_get_mq (struct GNUNET_SERVICE_Client *c)
{
  return c->mq;
}
 
 
/* end of service.c */