arm_api.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2009, 2010, 2012, 2013, 2016, 2019 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_arm_service.h"
#include "gnunet_protocols.h"
#include "arm.h"
 
#define LOG(kind, ...) GNUNET_log_from (kind, "arm-api", __VA_ARGS__)
 
 
struct GNUNET_ARM_Operation
{
  struct GNUNET_ARM_Operation *next;
 
  struct GNUNET_ARM_Operation *prev;
 
  struct GNUNET_ARM_Handle *h;
 
  GNUNET_ARM_ResultCallback result_cont;
 
  GNUNET_ARM_ServiceListCallback list_cont;
 
  void *cont_cls;
 
  struct GNUNET_SCHEDULER_Task *async;
 
  uint64_t id;
 
  enum GNUNET_ARM_Result starting_ret;
 
  struct GNUNET_DISK_FileHandle *rfd;
 
  int is_arm_stop;
};
 
 
struct GNUNET_ARM_Handle
{
  struct GNUNET_MQ_Handle *mq;
 
  const struct GNUNET_CONFIGURATION_Handle *cfg;
 
  struct GNUNET_ARM_Operation *operation_pending_head;
 
  struct GNUNET_ARM_Operation *operation_pending_tail;
 
  GNUNET_ARM_ConnectionStatusCallback conn_status;
 
  void *conn_status_cls;
 
  struct GNUNET_ARM_Operation *thm;
 
  struct GNUNET_SCHEDULER_Task *reconnect_task;
 
  struct GNUNET_TIME_Relative retry_backoff;
 
  uint64_t request_id_counter;
 
  int currently_up;
};
 
 
static enum GNUNET_GenericReturnValue
reconnect_arm (struct GNUNET_ARM_Handle *h);
 
 
static void
reconnect_arm_task (void *cls)
{
  struct GNUNET_ARM_Handle *h = cls;
 
  h->reconnect_task = NULL;
  reconnect_arm (h);
}
 
 
static void
reconnect_arm_later (struct GNUNET_ARM_Handle *h)
{
  struct GNUNET_ARM_Operation *op;
 
  if (NULL != h->mq)
  {
    GNUNET_MQ_destroy (h->mq);
    h->mq = NULL;
  }
  h->currently_up = GNUNET_NO;
  GNUNET_assert (NULL == h->reconnect_task);
  h->reconnect_task =
    GNUNET_SCHEDULER_add_delayed (h->retry_backoff,
                                  &reconnect_arm_task,
                                  h);
  while (NULL != (op = h->operation_pending_head))
  {
    if (NULL != op->result_cont)
      op->result_cont (op->cont_cls,
                       GNUNET_ARM_REQUEST_DISCONNECTED,
                       0);
    if (NULL != op->list_cont)
      op->list_cont (op->cont_cls,
                     GNUNET_ARM_REQUEST_DISCONNECTED,
                     0,
                     NULL);
    GNUNET_ARM_operation_cancel (op);
  }
  GNUNET_assert (NULL == h->operation_pending_head);
  h->retry_backoff = GNUNET_TIME_STD_BACKOFF (h->retry_backoff);
  if (NULL != h->conn_status)
    h->conn_status (h->conn_status_cls,
                    GNUNET_NO);
}
 
 
static struct GNUNET_ARM_Operation *
find_op_by_id (struct GNUNET_ARM_Handle *h,
               uint64_t id)
{
  for (struct GNUNET_ARM_Operation *result = h->operation_pending_head;
       NULL != result;
       result = result->next)
    if (id == result->id)
      return result;
  return NULL;
}
 
 
static void
handle_arm_result (void *cls,
                   const struct GNUNET_ARM_ResultMessage *res)
{
  struct GNUNET_ARM_Handle *h = cls;
  struct GNUNET_ARM_Operation *op;
  uint64_t id;
  enum GNUNET_ARM_Result result;
  GNUNET_ARM_ResultCallback result_cont;
  void *result_cont_cls;
 
  id = GNUNET_ntohll (res->arm_msg.request_id);
  op = find_op_by_id (h,
                      id);
  if (NULL == op)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Message with unknown id %llu\n",
         (unsigned long long) id);
    return;
  }
 
  result = (enum GNUNET_ARM_Result) ntohl (res->result);
  if ( (GNUNET_YES == op->is_arm_stop) &&
       (GNUNET_ARM_RESULT_STOPPING == result) )
  {
    /* special case: if we are stopping 'gnunet-service-arm', we do not just
       wait for the result message, but also wait for the service to close
       the connection (and then we have to close our client handle as well);
       this is done by installing a different receive handler, waiting for
       the connection to go down */if (NULL != h->thm)
    {
      GNUNET_break (0);
      op->result_cont (h->thm->cont_cls,
                       GNUNET_ARM_REQUEST_SENT_OK,
                       GNUNET_ARM_RESULT_IS_NOT_KNOWN);
      GNUNET_free (h->thm);
    }
    GNUNET_CONTAINER_DLL_remove (h->operation_pending_head,
                                 h->operation_pending_tail,
                                 op);
    h->thm = op;
    return;
  }
  result_cont = op->result_cont;
  result_cont_cls = op->cont_cls;
  GNUNET_ARM_operation_cancel (op);
  if (NULL != result_cont)
    result_cont (result_cont_cls,
                 GNUNET_ARM_REQUEST_SENT_OK,
                 result);
}
 
 
static const char *
pool_get (const char *pool_start,
          size_t pool_size,
          size_t str_index)
{
  const char *str_start;
  const char *end;
 
  if (str_index >= pool_size)
    return NULL;
  str_start = pool_start + str_index;
  end = memchr (str_start, 0, pool_size - str_index);
  if (NULL == end)
    return NULL;
  return str_start;
}
 
 
static enum GNUNET_GenericReturnValue
check_arm_list_result (void *cls,
                       const struct GNUNET_ARM_ListResultMessage *lres)
{
  uint16_t rcount = ntohs (lres->count);
  uint16_t msize = ntohs (lres->arm_msg.header.size) - sizeof(*lres);
  struct GNUNET_ARM_ServiceInfoMessage *ssm;
  size_t pool_size;
  char *pool_start;
 
  (void) cls;
  if ((rcount * sizeof (struct GNUNET_ARM_ServiceInfoMessage) > msize))
  {
    GNUNET_break_op (0);
    return GNUNET_NO;
  }
  ssm = (struct GNUNET_ARM_ServiceInfoMessage *) &lres[1];
  pool_start = (char *) (ssm + rcount);
  pool_size = msize - (rcount * sizeof (struct GNUNET_ARM_ServiceInfoMessage));
  for (unsigned int i = 0; i < rcount; i++)
  {
    uint16_t name_index = ntohs (ssm->name_index);
    uint16_t binary_index = ntohs (ssm->binary_index);
    if (NULL == pool_get (pool_start,
                          pool_size,
                          name_index))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    if (NULL == pool_get (pool_start,
                          pool_size,
                          binary_index))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    ssm++;
  }
  return GNUNET_OK;
}
 
 
static void
handle_arm_list_result (void *cls,
                        const struct GNUNET_ARM_ListResultMessage *lres)
{
  struct GNUNET_ARM_Handle *h = cls;
  uint16_t rcount = ntohs (lres->count);
  uint16_t msize = ntohs (lres->arm_msg.header.size) - sizeof(*lres);
  struct GNUNET_ARM_ServiceInfo list[rcount];
  struct GNUNET_ARM_ServiceInfoMessage *ssm;
  struct GNUNET_ARM_Operation *op;
  uint64_t id;
  size_t pool_size;
  char *pool_start;
 
  id = GNUNET_ntohll (lres->arm_msg.request_id);
  op = find_op_by_id (h, id);
  if (NULL == op)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Message with unknown id %llu\n",
         (unsigned long long) id);
    return;
  }
 
  GNUNET_assert ((rcount * sizeof (struct GNUNET_ARM_ServiceInfoMessage) <=
                  msize));
 
  ssm = (struct GNUNET_ARM_ServiceInfoMessage *) &lres[1];
  pool_start = (char *) (ssm + rcount);
  pool_size = msize - (rcount * sizeof (struct GNUNET_ARM_ServiceInfoMessage));
 
  for (unsigned int i = 0; i < rcount; i++)
  {
    uint16_t name_index = ntohs (ssm->name_index);
    uint16_t binary_index = ntohs (ssm->binary_index);
    const char *name;
    const char *binary;
 
    name = pool_get (pool_start, pool_size, name_index);
    binary = pool_get (pool_start, pool_size, binary_index);
    GNUNET_assert (NULL != name);
    GNUNET_assert (NULL != binary);
    list[i] = (struct GNUNET_ARM_ServiceInfo) {
      .name = name,
      .binary = binary,
      .status = ntohl (ssm->status),
      .last_started_at = GNUNET_TIME_absolute_ntoh (ssm->last_started_at),
      .restart_at = GNUNET_TIME_absolute_ntoh (ssm->restart_at),
      .last_exit_status = ntohs (ssm->last_exit_status),
    };
    ssm++;
  }
  if (NULL != op->list_cont)
    op->list_cont (op->cont_cls,
                   GNUNET_ARM_REQUEST_SENT_OK,
                   rcount,
                   list);
  GNUNET_ARM_operation_cancel (op);
}
 
 
static void
handle_confirm (void *cls,
                const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_ARM_Handle *h = cls;
 
  (void) msg;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Got confirmation from ARM that we are up!\n");
  if (GNUNET_NO == h->currently_up)
  {
    h->currently_up = GNUNET_YES;
    if (NULL != h->conn_status)
      h->conn_status (h->conn_status_cls, GNUNET_YES);
  }
}
 
 
static void
mq_error_handler (void *cls,
                  enum GNUNET_MQ_Error error)
{
  struct GNUNET_ARM_Handle *h = cls;
  struct GNUNET_ARM_Operation *op;
 
  (void) error;
  h->currently_up = GNUNET_NO;
  if (NULL != (op = h->thm))
  {
    h->thm = NULL;
    op->result_cont (op->cont_cls,
                     GNUNET_ARM_REQUEST_SENT_OK,
                     GNUNET_ARM_RESULT_STOPPED);
    GNUNET_free (op);
  }
  reconnect_arm_later (h);
}
 
 
static enum GNUNET_GenericReturnValue
reconnect_arm (struct GNUNET_ARM_Handle *h)
{
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_fixed_size (arm_result,
                             GNUNET_MESSAGE_TYPE_ARM_RESULT,
                             struct GNUNET_ARM_ResultMessage,
                             h),
    GNUNET_MQ_hd_var_size (arm_list_result,
                           GNUNET_MESSAGE_TYPE_ARM_LIST_RESULT,
                           struct GNUNET_ARM_ListResultMessage,
                           h),
    GNUNET_MQ_hd_fixed_size (confirm,
                             GNUNET_MESSAGE_TYPE_ARM_TEST,
                             struct GNUNET_MessageHeader,
                             h),
    GNUNET_MQ_handler_end ()
  };
  struct GNUNET_MessageHeader *test;
  struct GNUNET_MQ_Envelope *env;
 
  if (NULL != h->mq)
    return GNUNET_OK;
  GNUNET_assert (GNUNET_NO == h->currently_up);
  h->mq = GNUNET_CLIENT_connect (h->cfg,
                                 "arm",
                                 handlers,
                                 &mq_error_handler,
                                 h);
  if (NULL == h->mq)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "GNUNET_CLIENT_connect returned NULL\n");
    if (NULL != h->conn_status)
      h->conn_status (h->conn_status_cls,
                      GNUNET_SYSERR);
    return GNUNET_SYSERR;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending TEST message to ARM\n");
  env = GNUNET_MQ_msg (test,
                       GNUNET_MESSAGE_TYPE_ARM_TEST);
  GNUNET_MQ_send (h->mq, env);
  return GNUNET_OK;
}
 
 
struct GNUNET_ARM_Handle *
GNUNET_ARM_connect (
  const struct GNUNET_CONFIGURATION_Handle *cfg,
  GNUNET_ARM_ConnectionStatusCallback conn_status,
  void *conn_status_cls)
{
  struct GNUNET_ARM_Handle *h;
 
  h = GNUNET_new (struct GNUNET_ARM_Handle);
  h->cfg = cfg;
  h->conn_status = conn_status;
  h->conn_status_cls = conn_status_cls;
  if (GNUNET_OK != reconnect_arm (h))
  {
    GNUNET_free (h);
    return NULL;
  }
  return h;
}
 
 
void
GNUNET_ARM_disconnect (struct GNUNET_ARM_Handle *h)
{
  struct GNUNET_ARM_Operation *op;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from ARM service\n");
  while (NULL != (op = h->operation_pending_head))
  {
    GNUNET_CONTAINER_DLL_remove (h->operation_pending_head,
                                 h->operation_pending_tail,
                                 op);
    if (NULL != op->result_cont)
      op->result_cont (op->cont_cls,
                       GNUNET_ARM_REQUEST_DISCONNECTED,
                       0);
    if (NULL != op->list_cont)
      op->list_cont (op->cont_cls,
                     GNUNET_ARM_REQUEST_DISCONNECTED,
                     0,
                     NULL);
    if (NULL != op->async)
    {
      GNUNET_SCHEDULER_cancel (op->async);
      op->async = NULL;
    }
    GNUNET_free (op);
  }
  if (NULL != h->mq)
  {
    GNUNET_MQ_destroy (h->mq);
    h->mq = NULL;
  }
  if (NULL != h->reconnect_task)
  {
    GNUNET_SCHEDULER_cancel (h->reconnect_task);
    h->reconnect_task = NULL;
  }
  GNUNET_free (h);
}
 
 
static enum GNUNET_ARM_Result
start_arm_service (struct GNUNET_ARM_Handle *h,
                   enum GNUNET_OS_InheritStdioFlags std_inheritance,
                   struct GNUNET_DISK_FileHandle *sigfd)
{
  struct GNUNET_OS_Process *proc;
  char *cbinary;
  char *binary;
  char *quotedbinary;
  char *config;
  char *loprefix;
  char *lopostfix;
  int ld[2];
  int *lsocks;
 
  if (NULL == sigfd)
  {
    lsocks = NULL;
  }
  else
  {
    ld[0] = sigfd->fd;
    ld[1] = -1;
    lsocks = ld;
  }
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (h->cfg,
                                             "arm",
                                             "PREFIX",
                                             &loprefix))
    loprefix = GNUNET_strdup ("");
  else
    loprefix = GNUNET_CONFIGURATION_expand_dollar (h->cfg, loprefix);
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (h->cfg,
                                             "arm",
                                             "OPTIONS",
                                             &lopostfix))
    lopostfix = GNUNET_strdup ("");
  else
    lopostfix = GNUNET_CONFIGURATION_expand_dollar (h->cfg,
                                                    lopostfix);
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (h->cfg,
                                             "arm",
                                             "BINARY",
                                             &cbinary))
  {
    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
                               "arm",
                               "BINARY");
    GNUNET_free (loprefix);
    GNUNET_free (lopostfix);
    return GNUNET_ARM_RESULT_IS_NOT_KNOWN;
  }
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (h->cfg,
                                               "arm",
                                               "CONFIG",
                                               &config))
    config = NULL;
  binary = GNUNET_OS_get_libexec_binary_path (cbinary);
  GNUNET_asprintf (&quotedbinary,
                   "\"%s\"",
                   binary);
  GNUNET_free (cbinary);
  if ( (GNUNET_YES ==
        GNUNET_CONFIGURATION_have_value (h->cfg,
                                         "TESTING",
                                         "WEAKRANDOM")) &&
       (GNUNET_YES ==
        GNUNET_CONFIGURATION_get_value_yesno (h->cfg,
                                              "TESTING",
                                              "WEAKRANDOM")) &&
       (GNUNET_NO ==
        GNUNET_CONFIGURATION_have_value (h->cfg,
                                         "TESTING",
                                         "HOSTFILE")) )
  {
    /* Means we are ONLY running locally */
    /* we're clearly running a test, don't daemonize */
    if (NULL == config)
      proc = GNUNET_OS_start_process_s (std_inheritance,
                                        lsocks,
                                        loprefix,
                                        quotedbinary,
                                        /* no daemonization! */
                                        lopostfix,
                                        NULL);
    else
      proc = GNUNET_OS_start_process_s (std_inheritance,
                                        lsocks,
                                        loprefix,
                                        quotedbinary,
                                        "-c",
                                        config,
                                        /* no daemonization! */
                                        lopostfix,
                                        NULL);
  }
  else
  {
    if (NULL == config)
      proc = GNUNET_OS_start_process_s (std_inheritance,
                                        lsocks,
                                        loprefix,
                                        quotedbinary,
                                        "-d",  /* do daemonize */
                                        lopostfix,
                                        NULL);
    else
      proc = GNUNET_OS_start_process_s (std_inheritance,
                                        lsocks,
                                        loprefix,
                                        quotedbinary,
                                        "-c",
                                        config,
                                        "-d",  /* do daemonize */
                                        lopostfix,
                                        NULL);
  }
  GNUNET_free (binary);
  GNUNET_free (quotedbinary);
  if (NULL != config)
    GNUNET_free (config);
  GNUNET_free (loprefix);
  GNUNET_free (lopostfix);
  if (NULL == proc)
    return GNUNET_ARM_RESULT_START_FAILED;
  GNUNET_OS_process_destroy (proc);
  return GNUNET_ARM_RESULT_STARTING;
}
 
 
void
GNUNET_ARM_operation_cancel (struct GNUNET_ARM_Operation *op)
{
  struct GNUNET_ARM_Handle *h = op->h;
 
  if (NULL != op->async)
  {
    GNUNET_SCHEDULER_cancel (op->async);
    op->async = NULL;
  }
  if (NULL != op->rfd)
  {
    GNUNET_DISK_file_close (op->rfd);
    op->rfd = NULL;
  }
  if (h->thm == op)
  {
    op->result_cont = NULL;
    return;
  }
  GNUNET_CONTAINER_DLL_remove (h->operation_pending_head,
                               h->operation_pending_tail,
                               op);
  GNUNET_free (op);
}
 
 
static struct GNUNET_ARM_Operation *
change_service (struct GNUNET_ARM_Handle *h,
                const char *service_name,
                GNUNET_ARM_ResultCallback cb,
                void *cb_cls,
                uint16_t type)
{
  struct GNUNET_ARM_Operation *op;
  size_t slen;
  struct GNUNET_MQ_Envelope *env;
  struct GNUNET_ARM_Message *msg;
 
  slen = strlen (service_name) + 1;
  if (slen + sizeof(struct GNUNET_ARM_Message) >= GNUNET_MAX_MESSAGE_SIZE)
  {
    GNUNET_break (0);
    return NULL;
  }
  if (0 == h->request_id_counter)
    h->request_id_counter++;
  op = GNUNET_new (struct GNUNET_ARM_Operation);
  op->h = h;
  op->result_cont = cb;
  op->cont_cls = cb_cls;
  op->id = h->request_id_counter++;
  GNUNET_CONTAINER_DLL_insert_tail (h->operation_pending_head,
                                    h->operation_pending_tail,
                                    op);
  env = GNUNET_MQ_msg_extra (msg,
                             slen,
                             type);
  msg->reserved = htonl (0);
  msg->request_id = GNUNET_htonll (op->id);
  GNUNET_memcpy (&msg[1],
                 service_name,
                 slen);
  GNUNET_MQ_send (h->mq, env);
  return op;
}
 
 
static void
notify_running (void *cls)
{
  struct GNUNET_ARM_Operation *op = cls;
  struct GNUNET_ARM_Handle *h = op->h;
 
  op->async = NULL;
  GNUNET_CONTAINER_DLL_remove (h->operation_pending_head,
                               h->operation_pending_tail,
                               op);
  if (NULL != op->result_cont)
    op->result_cont (op->cont_cls,
                     GNUNET_ARM_REQUEST_SENT_OK,
                     GNUNET_ARM_RESULT_IS_STARTED_ALREADY);
  if ( (GNUNET_YES == h->currently_up) &&
       (NULL != h->conn_status) )
    h->conn_status (h->conn_status_cls,
                    GNUNET_YES);
  GNUNET_free (op);
}
 
 
static void
notify_starting (void *cls)
{
  struct GNUNET_ARM_Operation *op = cls;
  struct GNUNET_ARM_Handle *h = op->h;
 
  op->async = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Notifying client that we started the ARM service\n");
  GNUNET_CONTAINER_DLL_remove (h->operation_pending_head,
                               h->operation_pending_tail,
                               op);
  if (NULL != op->result_cont)
    op->result_cont (op->cont_cls,
                     GNUNET_ARM_REQUEST_SENT_OK,
                     op->starting_ret);
  GNUNET_DISK_file_close (op->rfd);
  GNUNET_free (op);
}
 
 
struct GNUNET_ARM_Operation *
GNUNET_ARM_request_service_start (
  struct GNUNET_ARM_Handle *h,
  const char *service_name,
  enum GNUNET_OS_InheritStdioFlags
  std_inheritance,
  GNUNET_ARM_ResultCallback cont,
  void *cont_cls)
{
  struct GNUNET_ARM_Operation *op;
  enum GNUNET_ARM_Result ret;
  struct GNUNET_DISK_PipeHandle *sig;
  struct GNUNET_DISK_FileHandle *wsig;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Starting service `%s'\n",
       service_name);
  if (0 != strcasecmp ("arm",
                       service_name))
    return change_service (h,
                           service_name,
                           cont,
                           cont_cls,
                           GNUNET_MESSAGE_TYPE_ARM_START);
 
  /* Possible cases:
   * 1) We're connected to ARM already. Invoke the callback immediately.
   * 2) We're not connected to ARM.
   *    Cancel any reconnection attempts temporarily, then perform
   *    a service test.
   */
  if (GNUNET_YES == h->currently_up)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "ARM is already running\n");
    op = GNUNET_new (struct GNUNET_ARM_Operation);
    op->h = h;
    op->result_cont = cont;
    op->cont_cls = cont_cls;
    GNUNET_CONTAINER_DLL_insert_tail (h->operation_pending_head,
                                      h->operation_pending_tail,
                                      op);
    op->async = GNUNET_SCHEDULER_add_now (&notify_running, op);
    return op;
  }
  /* This is an inherently uncertain choice, as it is of course
     theoretically possible that ARM is up and we just did not
     yet complete the MQ handshake.  However, given that users
     are unlikely to hammer 'gnunet-arm -s' on a busy system,
     the above check should catch 99.99% of the cases where ARM
     is already running. */
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Starting ARM service\n");
  if (NULL == (sig = GNUNET_DISK_pipe (GNUNET_DISK_PF_NONE)))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                         "pipe");
    ret = GNUNET_ARM_RESULT_START_FAILED;
  }
  else
  {
    wsig = GNUNET_DISK_pipe_detach_end (sig,
                                        GNUNET_DISK_PIPE_END_WRITE);
    ret = start_arm_service (h,
                             std_inheritance,
                             wsig);
    GNUNET_DISK_file_close (wsig);
    if (GNUNET_ARM_RESULT_STARTING == ret)
      reconnect_arm (h);
  }
  op = GNUNET_new (struct GNUNET_ARM_Operation);
  op->h = h;
  op->result_cont = cont;
  op->cont_cls = cont_cls;
  GNUNET_CONTAINER_DLL_insert_tail (h->operation_pending_head,
                                    h->operation_pending_tail,
                                    op);
  op->starting_ret = ret;
  if (NULL != sig)
  {
    op->rfd = GNUNET_DISK_pipe_detach_end (sig,
                                           GNUNET_DISK_PIPE_END_READ);
    /* Wait at most a minute for gnunet-service-arm to be up, as beyond
       that something clearly just went wrong */
    op->async = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_MINUTES,
                                                op->rfd,
                                                &notify_starting,
                                                op);
    GNUNET_DISK_pipe_close (sig);
  }
  else
  {
    op->async = GNUNET_SCHEDULER_add_now (&notify_starting,
                                          op);
  }
  return op;
}
 
 
struct GNUNET_ARM_Operation *
GNUNET_ARM_request_service_stop (
  struct GNUNET_ARM_Handle *h,
  const char *service_name,
  GNUNET_ARM_ResultCallback cont,
  void *cont_cls)
{
  struct GNUNET_ARM_Operation *op;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Stopping service `%s'\n",
       service_name);
  op = change_service (h,
                       service_name,
                       cont,
                       cont_cls,
                       GNUNET_MESSAGE_TYPE_ARM_STOP);
  if (NULL == op)
    return NULL;
  /* If the service is ARM, set a flag as we will use MQ errors
     to detect that the process is really gone. */
  if (0 == strcasecmp (service_name,
                       "arm"))
    op->is_arm_stop = GNUNET_YES;
  return op;
}
 
 
struct GNUNET_ARM_Operation *
GNUNET_ARM_request_service_list (
  struct GNUNET_ARM_Handle *h,
  GNUNET_ARM_ServiceListCallback cont,
  void *cont_cls)
{
  struct GNUNET_ARM_Operation *op;
  struct GNUNET_MQ_Envelope *env;
  struct GNUNET_ARM_Message *msg;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Requesting LIST from ARM service\n");
  if (0 == h->request_id_counter)
    h->request_id_counter++;
  op = GNUNET_new (struct GNUNET_ARM_Operation);
  op->h = h;
  op->list_cont = cont;
  op->cont_cls = cont_cls;
  op->id = h->request_id_counter++;
  GNUNET_CONTAINER_DLL_insert_tail (h->operation_pending_head,
                                    h->operation_pending_tail,
                                    op);
  env = GNUNET_MQ_msg (msg,
                       GNUNET_MESSAGE_TYPE_ARM_LIST);
  msg->reserved = htonl (0);
  msg->request_id = GNUNET_htonll (op->id);
  GNUNET_MQ_send (h->mq, env);
  return op;
}
 
 
/* end of arm_api.c */