Imported Upstream version 0.9.2upstream/0.9.2

1 files changed, 1840 insertions, 0 deletions

diff --git a/src/util/service.c b/src/util/service.c
new file mode 100644
index 0000000..243e7da
--- /dev/null
+++ b/src/util/service.c
@@ -0,0 +1,1840 @@
+/*
+     This file is part of GNUnet.
+     (C) 2009 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, 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
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file util/service.c
+ * @brief functions related to starting services
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_configuration_lib.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_directories.h"
+#include "gnunet_disk_lib.h"
+#include "gnunet_getopt_lib.h"
+#include "gnunet_os_lib.h"
+#include "gnunet_protocols.h"
+#include "gnunet_resolver_service.h"
+#include "gnunet_server_lib.h"
+#include "gnunet_service_lib.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
+
+#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util", syscall, filename)
+
+#define DEBUG_SERVICE GNUNET_EXTRA_LOGGING
+
+/* ******************* access control ******************** */
+
+/**
+ * @brief IPV4 network in CIDR notation.
+ */
+struct IPv4NetworkSet
+{
+  struct in_addr network;
+  struct in_addr netmask;
+};
+
+/**
+ * @brief network in CIDR notation for IPV6.
+ */
+struct IPv6NetworkSet
+{
+  struct in6_addr network;
+  struct in6_addr netmask;
+};
+
+
+/**
+ * Parse a network specification. The argument specifies
+ * a list of networks. The format is
+ * <tt>[network/netmask;]*</tt> (no whitespace, must be terminated
+ * with a semicolon). The network must be given in dotted-decimal
+ * notation. The netmask can be given in CIDR notation (/16) or
+ * in dotted-decimal (/255.255.0.0).
+ * <p>
+ * @param routeList a string specifying the forbidden networks
+ * @return the converted list, NULL if the synatx is flawed
+ */
+static struct IPv4NetworkSet *
+parse_ipv4_specification (const char *routeList)
+{
+  unsigned int count;
+  unsigned int i;
+  unsigned int j;
+  unsigned int len;
+  int cnt;
+  unsigned int pos;
+  unsigned int temps[8];
+  int slash;
+  struct IPv4NetworkSet *result;
+
+  if (routeList == NULL)
+    return NULL;
+  len = strlen (routeList);
+  if (len == 0)
+    return NULL;
+  count = 0;
+  for (i = 0; i < len; i++)
+    if (routeList[i] == ';')
+      count++;
+  result = GNUNET_malloc (sizeof (struct IPv4NetworkSet) * (count + 1));
+  /* add termination */
+  memset (result, 0, sizeof (struct IPv4NetworkSet) * (count + 1));
+  i = 0;
+  pos = 0;
+  while (i < count)
+  {
+    cnt =
+        sscanf (&routeList[pos], "%u.%u.%u.%u/%u.%u.%u.%u;", &temps[0],
+                &temps[1], &temps[2], &temps[3], &temps[4], &temps[5],
+                &temps[6], &temps[7]);
+    if (cnt == 8)
+    {
+      for (j = 0; j < 8; j++)
+        if (temps[j] > 0xFF)
+        {
+          LOG (GNUNET_ERROR_TYPE_ERROR, _("Invalid format for IP: `%s'\n"),
+               &routeList[pos]);
+          GNUNET_free (result);
+          return NULL;
+        }
+      result[i].network.s_addr =
+          htonl ((temps[0] << 24) + (temps[1] << 16) + (temps[2] << 8) +
+                 temps[3]);
+      result[i].netmask.s_addr =
+          htonl ((temps[4] << 24) + (temps[5] << 16) + (temps[6] << 8) +
+                 temps[7]);
+      while (routeList[pos] != ';')
+        pos++;
+      pos++;
+      i++;
+      continue;
+    }
+    /* try second notation */
+    cnt =
+        sscanf (&routeList[pos], "%u.%u.%u.%u/%u;", &temps[0], &temps[1],
+                &temps[2], &temps[3], &slash);
+    if (cnt == 5)
+    {
+      for (j = 0; j < 4; j++)
+        if (temps[j] > 0xFF)
+        {
+          LOG (GNUNET_ERROR_TYPE_ERROR, _("Invalid format for IP: `%s'\n"),
+               &routeList[pos]);
+          GNUNET_free (result);
+          return NULL;
+        }
+      result[i].network.s_addr =
+          htonl ((temps[0] << 24) + (temps[1] << 16) + (temps[2] << 8) +
+                 temps[3]);
+      if ((slash <= 32) && (slash >= 0))
+      {
+        result[i].netmask.s_addr = 0;
+        while (slash > 0)
+        {
+          result[i].netmask.s_addr =
+              (result[i].netmask.s_addr >> 1) + 0x80000000;
+          slash--;
+        }
+        result[i].netmask.s_addr = htonl (result[i].netmask.s_addr);
+        while (routeList[pos] != ';')
+          pos++;
+        pos++;
+        i++;
+        continue;
+      }
+      else
+      {
+        LOG (GNUNET_ERROR_TYPE_ERROR,
+             _("Invalid network notation ('/%d' is not legal in IPv4 CIDR)."),
+             slash);
+        GNUNET_free (result);
+        return NULL;            /* error */
+      }
+    }
+    /* try third notation */
+    slash = 32;
+    cnt =
+        sscanf (&routeList[pos], "%u.%u.%u.%u;", &temps[0], &temps[1],
+                &temps[2], &temps[3]);
+    if (cnt == 4)
+    {
+      for (j = 0; j < 4; j++)
+        if (temps[j] > 0xFF)
+        {
+          LOG (GNUNET_ERROR_TYPE_ERROR, _("Invalid format for IP: `%s'\n"),
+               &routeList[pos]);
+          GNUNET_free (result);
+          return NULL;
+        }
+      result[i].network.s_addr =
+          htonl ((temps[0] << 24) + (temps[1] << 16) + (temps[2] << 8) +
+                 temps[3]);
+      result[i].netmask.s_addr = 0;
+      while (slash > 0)
+      {
+        result[i].netmask.s_addr = (result[i].netmask.s_addr >> 1) + 0x80000000;
+        slash--;
+      }
+      result[i].netmask.s_addr = htonl (result[i].netmask.s_addr);
+      while (routeList[pos] != ';')
+        pos++;
+      pos++;
+      i++;
+      continue;
+    }
+    LOG (GNUNET_ERROR_TYPE_ERROR, _("Invalid format for IP: `%s'\n"),
+         &routeList[pos]);
+    GNUNET_free (result);
+    return NULL;                /* error */
+  }
+  if (pos < strlen (routeList))
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR, _("Invalid format for IP: `%s'\n"),
+         &routeList[pos]);
+    GNUNET_free (result);
+    return NULL;                /* oops */
+  }
+  return result;                /* ok */
+}
+
+
+/**
+ * Parse a network specification. The argument specifies
+ * a list of networks. The format is
+ * <tt>[network/netmask;]*</tt> (no whitespace, must be terminated
+ * with a semicolon). The network must be given in colon-hex
+ * notation.  The netmask must be given in CIDR notation (/16) or
+ * can be omitted to specify a single host.
+ * <p>
+ * @param routeListX a string specifying the forbidden networks
+ * @return the converted list, NULL if the synatx is flawed
+ */
+static struct IPv6NetworkSet *
+parse_ipv6_specification (const char *routeListX)
+{
+  unsigned int count;
+  unsigned int i;
+  unsigned int len;
+  unsigned int pos;
+  int start;
+  int slash;
+  int ret;
+  char *routeList;
+  struct IPv6NetworkSet *result;
+  unsigned int bits;
+  unsigned int off;
+  int save;
+
+  if (routeListX == NULL)
+    return NULL;
+  len = strlen (routeListX);
+  if (len == 0)
+    return NULL;
+  routeList = GNUNET_strdup (routeListX);
+  count = 0;
+  for (i = 0; i < len; i++)
+    if (routeList[i] == ';')
+      count++;
+  if (routeList[len - 1] != ';')
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _("Invalid network notation (does not end with ';': `%s')\n"),
+         routeList);
+    GNUNET_free (routeList);
+    return NULL;
+  }
+
+  result = GNUNET_malloc (sizeof (struct IPv6NetworkSet) * (count + 1));
+  memset (result, 0, sizeof (struct IPv6NetworkSet) * (count + 1));
+  i = 0;
+  pos = 0;
+  while (i < count)
+  {
+    start = pos;
+    while (routeList[pos] != ';')
+      pos++;
+    slash = pos;
+    while ((slash >= start) && (routeList[slash] != '/'))
+      slash--;
+    if (slash < start)
+    {
+      memset (&result[i].netmask, 0xFF, sizeof (struct in6_addr));
+      slash = pos;
+    }
+    else
+    {
+      routeList[pos] = '\0';
+      ret = inet_pton (AF_INET6, &routeList[slash + 1], &result[i].netmask);
+      if (ret <= 0)
+      {
+        save = errno;
+        if ((1 != SSCANF (&routeList[slash + 1], "%u", &bits)) || (bits >= 128))
+        {
+          if (ret == 0)
+            LOG (GNUNET_ERROR_TYPE_ERROR, _("Wrong format `%s' for netmask\n"),
+                 &routeList[slash + 1]);
+          else
+          {
+            errno = save;
+            LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "inet_pton");
+          }
+          GNUNET_free (result);
+          GNUNET_free (routeList);
+          return NULL;
+        }
+        off = 0;
+        while (bits > 8)
+        {
+          result[i].netmask.s6_addr[off++] = 0xFF;
+          bits -= 8;
+        }
+        while (bits > 0)
+        {
+          result[i].netmask.s6_addr[off] =
+              (result[i].netmask.s6_addr[off] >> 1) + 0x80;
+          bits--;
+        }
+      }
+    }
+    routeList[slash] = '\0';
+    ret = inet_pton (AF_INET6, &routeList[start], &result[i].network);
+    if (ret <= 0)
+    {
+      if (ret == 0)
+        LOG (GNUNET_ERROR_TYPE_ERROR, _("Wrong format `%s' for network\n"),
+             &routeList[slash + 1]);
+      else
+        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "inet_pton");
+      GNUNET_free (result);
+      GNUNET_free (routeList);
+      return NULL;
+    }
+    pos++;
+    i++;
+  }
+  GNUNET_free (routeList);
+  return result;
+}
+
+
+/**
+ * Check if the given IP address is in the list of IP addresses.
+ *
+ * @param list a list of networks
+ * @param add the IP to check (in network byte order)
+ * @return GNUNET_NO if the IP is not in the list, GNUNET_YES if it it is
+ */
+static int
+check_ipv4_listed (const struct IPv4NetworkSet *list, const struct in_addr *add)
+{
+  int i;
+
+  i = 0;
+  if (list == NULL)
+    return GNUNET_NO;
+
+  while ((list[i].network.s_addr != 0) || (list[i].netmask.s_addr != 0))
+  {
+    if ((add->s_addr & list[i].netmask.s_addr) ==
+        (list[i].network.s_addr & list[i].netmask.s_addr))
+      return GNUNET_YES;
+    i++;
+  }
+  return GNUNET_NO;
+}
+
+/**
+ * Check if the given IP address is in the list of IP addresses.
+ *
+ * @param list a list of networks
+ * @param ip the IP to check (in network byte order)
+ * @return GNUNET_NO if the IP is not in the list, GNUNET_YES if it it is
+ */
+static int
+check_ipv6_listed (const struct IPv6NetworkSet *list, const struct in6_addr *ip)
+{
+  unsigned int i;
+  unsigned int j;
+  struct in6_addr zero;
+
+  if (list == NULL)
+    return GNUNET_NO;
+
+  memset (&zero, 0, sizeof (struct in6_addr));
+  i = 0;
+NEXT:
+  while (memcmp (&zero, &list[i].network, sizeof (struct in6_addr)) != 0)
+  {
+    for (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]))
+      {
+        i++;
+        goto NEXT;
+      }
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+
+/* ****************** service struct ****************** */
+
+
+/**
+ * Context for "service_task".
+ */
+struct GNUNET_SERVICE_Context
+{
+  /**
+   * Our configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Handle for the server.
+   */
+  struct GNUNET_SERVER_Handle *server;
+
+  /**
+   * NULL-terminated array of addresses to bind to, NULL if we got pre-bound
+   * listen sockets.
+   */
+  struct sockaddr **addrs;
+
+  /**
+   * Name of our service.
+   */
+  const char *serviceName;
+
+  /**
+   * Main service-specific task to run.
+   */
+  GNUNET_SERVICE_Main task;
+
+  /**
+   * Closure for task.
+   */
+  void *task_cls;
+
+  /**
+   * IPv4 addresses that are not allowed to connect.
+   */
+  struct IPv4NetworkSet *v4_denied;
+
+  /**
+   * IPv6 addresses that are not allowed to connect.
+   */
+  struct IPv6NetworkSet *v6_denied;
+
+  /**
+   * IPv4 addresses that are allowed to connect (if not
+   * set, all are allowed).
+   */
+  struct IPv4NetworkSet *v4_allowed;
+
+  /**
+   * IPv6 addresses that are allowed to connect (if not
+   * set, all are allowed).
+   */
+  struct IPv6NetworkSet *v6_allowed;
+
+  /**
+   * My (default) message handlers.  Adjusted copy
+   * of "defhandlers".
+   */
+  struct GNUNET_SERVER_MessageHandler *my_handlers;
+
+  /**
+   * Array of the lengths of the entries in addrs.
+   */
+  socklen_t *addrlens;
+
+  /**
+   * NULL-terminated array of listen sockets we should take over.
+   */
+  struct GNUNET_NETWORK_Handle **lsocks;
+
+  /**
+   * Idle timeout for server.
+   */
+  struct GNUNET_TIME_Relative timeout;
+
+  /**
+   * Overall success/failure of the service start.
+   */
+  int ret;
+
+  /**
+   * If we are daemonizing, this FD is set to the
+   * pipe to the parent.  Send '.' if we started
+   * ok, '!' if not.  -1 if we are not daemonizing.
+   */
+  int ready_confirm_fd;
+
+  /**
+   * Do we close connections if we receive messages
+   * for which we have no handler?
+   */
+  int require_found;
+
+  /**
+   * Do we require a matching UID for UNIX domain socket connections?
+   * GNUNET_NO means that the UID does not have to match (however,
+   * "match_gid" may still impose other access control checks).
+   */
+  int match_uid;
+
+  /**
+   * Do we require a matching GID for UNIX domain socket connections?
+   * Ignored if "match_uid" is GNUNET_YES.  Note that this is about
+   * checking that the client's UID is in our group OR that the
+   * client's GID is our GID.  If both "match_gid" and "match_uid" are
+   * "GNUNET_NO", all users on the local system have access.
+   */
+  int match_gid;
+
+  /**
+   * Our options.
+   */
+  enum GNUNET_SERVICE_Options options;
+
+};
+
+
+/* ****************** message handlers ****************** */
+
+static size_t
+write_test (void *cls, size_t size, void *buf)
+{
+  struct GNUNET_SERVER_Client *client = cls;
+  struct GNUNET_MessageHeader *msg;
+
+  if (size < sizeof (struct GNUNET_MessageHeader))
+  {
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return 0;                   /* client disconnected */
+  }
+  msg = (struct GNUNET_MessageHeader *) buf;
+  msg->type = htons (GNUNET_MESSAGE_TYPE_TEST);
+  msg->size = htons (sizeof (struct GNUNET_MessageHeader));
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  return sizeof (struct GNUNET_MessageHeader);
+}
+
+/**
+ * Handler for TEST message.
+ *
+ * @param cls closure (refers to service)
+ * @param client identification of the client
+ * @param message the actual message
+ */
+static void
+handle_test (void *cls, struct GNUNET_SERVER_Client *client,
+             const struct GNUNET_MessageHeader *message)
+{
+  /* simply bounce message back to acknowledge */
+  if (NULL ==
+      GNUNET_SERVER_notify_transmit_ready (client,
+                                           sizeof (struct GNUNET_MessageHeader),
+                                           GNUNET_TIME_UNIT_FOREVER_REL,
+                                           &write_test, client))
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+}
+
+
+/**
+ * Default handlers for all services.  Will be copied and the
+ * "callback_cls" fields will be replaced with the specific service
+ * struct.
+ */
+static const struct GNUNET_SERVER_MessageHandler defhandlers[] = {
+  {&handle_test, NULL, GNUNET_MESSAGE_TYPE_TEST,
+   sizeof (struct GNUNET_MessageHeader)},
+  {NULL, NULL, 0, 0}
+};
+
+
+
+/* ****************** service core routines ************** */
+
+
+/**
+ * Check if access to the service is allowed from the given address.
+ *
+ * @param cls closure
+ * @param uc credentials, if available, otherwise NULL
+ * @param addr address
+ * @param addrlen length of address
+ * @return GNUNET_YES to allow, GNUNET_NO to deny, GNUNET_SYSERR
+ *   for unknown address family (will be denied).
+ */
+static int
+check_access (void *cls, const struct GNUNET_CONNECTION_Credentials *uc,
+              const struct sockaddr *addr, socklen_t addrlen)
+{
+  struct GNUNET_SERVICE_Context *sctx = cls;
+  const struct sockaddr_in *i4;
+  const struct sockaddr_in6 *i6;
+  int ret;
+
+  switch (addr->sa_family)
+  {
+  case AF_INET:
+    GNUNET_assert (addrlen == sizeof (struct sockaddr_in));
+    i4 = (const struct sockaddr_in *) addr;
+    ret = ((sctx->v4_allowed == NULL) ||
+           (check_ipv4_listed (sctx->v4_allowed, &i4->sin_addr))) &&
+        ((sctx->v4_denied == NULL) ||
+         (!check_ipv4_listed (sctx->v4_denied, &i4->sin_addr)));
+    break;
+  case AF_INET6:
+    GNUNET_assert (addrlen == sizeof (struct sockaddr_in6));
+    i6 = (const struct sockaddr_in6 *) addr;
+    ret = ((sctx->v6_allowed == NULL) ||
+           (check_ipv6_listed (sctx->v6_allowed, &i6->sin6_addr))) &&
+        ((sctx->v6_denied == NULL) ||
+         (!check_ipv6_listed (sctx->v6_denied, &i6->sin6_addr)));
+    break;
+#ifndef WINDOWS
+  case AF_UNIX:
+    ret = GNUNET_OK;            /* always OK for now */
+    if (sctx->match_uid == GNUNET_YES) 
+    {
+      /* UID match required */
+      ret = (uc != NULL) && (uc->uid == geteuid ());
+    }
+    else if (sctx->match_gid == GNUNET_YES) 
+    {
+      /* group match required */
+      if (uc == NULL) 
+      {
+	/* no credentials, group match not possible */
+	ret = GNUNET_NO;
+      }
+      else
+      {
+	struct group *grp;
+	unsigned int i;
+
+	if (uc->gid != getegid())
+	{
+	  /* default group did not match, but maybe the user is in our group, let's check */
+	  grp = getgrgid (getegid ());
+	  if (NULL == grp)
+	  {
+	    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "getgrgid");
+	    return GNUNET_NO;
+	  }
+	  ret = GNUNET_NO;
+	  for (i=0; NULL != grp->gr_mem[i]; i++)
+	  {
+	    struct passwd *nam = getpwnam (grp->gr_mem[i]);
+	    if (NULL == nam)
+	      continue; /* name in group that is not in user DB !? */
+	    if (nam->pw_uid == uc->uid)
+	    {
+	      /* yes, uid is in our group, allow! */
+	      ret = GNUNET_YES;
+	      break;
+	    }
+	  }
+	}
+      }
+    }
+    if (GNUNET_NO == ret)
+      LOG (GNUNET_ERROR_TYPE_WARNING, _("Access denied to UID %d / GID %d\n"),
+           (uc == NULL) ? -1 : uc->uid, (uc == NULL) ? -1 : uc->gid);
+    break;
+#endif
+  default:
+    LOG (GNUNET_ERROR_TYPE_WARNING, _("Unknown address family %d\n"),
+         addr->sa_family);
+    return GNUNET_SYSERR;
+  }
+  if (ret != GNUNET_OK)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+         _("Access from `%s' denied to service `%s'\n"), GNUNET_a2s (addr,
+                                                                     addrlen),
+         sctx->serviceName);
+  }
+  return ret;
+}
+
+
+/**
+ * Get the name of the file where we will
+ * write the PID of the service.
+ */
+static char *
+get_pid_file_name (struct GNUNET_SERVICE_Context *sctx)
+{
+
+  char *pif;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_filename (sctx->cfg, sctx->serviceName,
+                                               "PIDFILE", &pif))
+    return NULL;
+  return pif;
+}
+
+
+/**
+ * Parse an IPv4 access control list.
+ */
+static int
+process_acl4 (struct IPv4NetworkSet **ret, struct GNUNET_SERVICE_Context *sctx,
+              const char *option)
+{
+  char *opt;
+
+  if (!GNUNET_CONFIGURATION_have_value (sctx->cfg, sctx->serviceName, option))
+    return GNUNET_OK;
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CONFIGURATION_get_value_string (sctx->cfg,
+                                                       sctx->serviceName,
+                                                       option, &opt));
+  if (NULL == (*ret = parse_ipv4_specification (opt)))
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+         _("Could not parse IPv4 network specification `%s' for `%s:%s'\n"),
+         opt, sctx->serviceName, option);
+    GNUNET_free (opt);
+    return GNUNET_SYSERR;
+  }
+  GNUNET_free (opt);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Parse an IPv4 access control list.
+ */
+static int
+process_acl6 (struct IPv6NetworkSet **ret, struct GNUNET_SERVICE_Context *sctx,
+              const char *option)
+{
+  char *opt;
+
+  if (!GNUNET_CONFIGURATION_have_value (sctx->cfg, sctx->serviceName, option))
+    return GNUNET_OK;
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CONFIGURATION_get_value_string (sctx->cfg,
+                                                       sctx->serviceName,
+                                                       option, &opt));
+  if (NULL == (*ret = parse_ipv6_specification (opt)))
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+         _("Could not parse IPv6 network specification `%s' for `%s:%s'\n"),
+         opt, sctx->serviceName, option);
+    GNUNET_free (opt);
+    return GNUNET_SYSERR;
+  }
+  GNUNET_free (opt);
+  return GNUNET_OK;
+}
+
+/**
+ * Add the given UNIX domain path as an address to the
+ * list (as the first entry).
+ *
+ * @param saddrs array to update
+ * @param saddrlens where to store the address length
+ * @param unixpath path to add
+ */
+static void
+add_unixpath (struct sockaddr **saddrs, socklen_t * saddrlens,
+              const char *unixpath)
+{
+#ifdef AF_UNIX
+  struct sockaddr_un *un;
+  size_t slen;
+
+  un = GNUNET_malloc (sizeof (struct sockaddr_un));
+  un->sun_family = AF_UNIX;
+  slen = strlen (unixpath) + 1;
+  if (slen >= sizeof (un->sun_path))
+    slen = sizeof (un->sun_path) - 1;
+  memcpy (un->sun_path, unixpath, slen);
+  un->sun_path[slen] = '\0';
+  slen = sizeof (struct sockaddr_un);
+#if LINUX
+  un->sun_path[0] = '\0';
+#endif
+#if HAVE_SOCKADDR_IN_SIN_LEN
+  un->sun_len = (u_char) slen;
+#endif
+  *saddrs = (struct sockaddr *) un;
+  *saddrlens = slen;
+#else
+  /* this function should never be called
+   * unless AF_UNIX is defined! */
+  GNUNET_assert (0);
+#endif
+}
+
+
+/**
+ * Get the list of addresses that a server for the given service
+ * should bind to.
+ *
+ * @param serviceName name of the service
+ * @param cfg configuration (which specifies the addresses)
+ * @param addrs set (call by reference) to an array of pointers to the
+ *              addresses the server should bind to and listen on; the
+ *              array will be NULL-terminated (on success)
+ * @param addr_lens set (call by reference) to an array of the lengths
+ *              of the respective 'struct sockaddr' struct in the 'addrs'
+ *              array (on success)
+ * @return number of addresses found on success,
+ *              GNUNET_SYSERR if the configuration
+ *              did not specify reasonable finding information or
+ *              if it specified a hostname that could not be resolved;
+ *              GNUNET_NO if the number of addresses configured is
+ *              zero (in this case, '*addrs' and '*addr_lens' will be
+ *              set to NULL).
+ */
+int
+GNUNET_SERVICE_get_server_addresses (const char *serviceName,
+                                     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;
+  if (GNUNET_CONFIGURATION_have_value (cfg, serviceName, "DISABLEV6"))
+  {
+    if (GNUNET_SYSERR ==
+        (disablev6 =
+         GNUNET_CONFIGURATION_get_value_yesno (cfg, serviceName, "DISABLEV6")))
+      return GNUNET_SYSERR;
+  }
+  else
+    disablev6 = GNUNET_NO;
+
+  if (!disablev6)
+  {
+    /* probe IPv6 support */
+    desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_STREAM, 0);
+    if (NULL == desc)
+    {
+      if ((errno == ENOBUFS) || (errno == ENOMEM) || (errno == ENFILE) ||
+          (errno == EACCES))
+      {
+        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "socket");
+        return GNUNET_SYSERR;
+      }
+      LOG (GNUNET_ERROR_TYPE_INFO,
+           _
+           ("Disabling IPv6 support for service `%s', failed to create IPv6 socket: %s\n"),
+           serviceName, STRERROR (errno));
+      disablev6 = GNUNET_YES;
+    }
+    else
+    {
+      GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (desc));
+      desc = NULL;
+    }
+  }
+
+  port = 0;
+  if (GNUNET_CONFIGURATION_have_value (cfg, serviceName, "PORT"))
+  {
+    GNUNET_break (GNUNET_OK ==
+                  GNUNET_CONFIGURATION_get_value_number (cfg, serviceName,
+                                                         "PORT", &port));
+    if (port > 65535)
+    {
+      LOG (GNUNET_ERROR_TYPE_ERROR,
+           _("Require valid port number for service `%s' in configuration!\n"),
+           serviceName);
+      return GNUNET_SYSERR;
+    }
+  }
+
+  if (GNUNET_CONFIGURATION_have_value (cfg, serviceName, "BINDTO"))
+  {
+    GNUNET_break (GNUNET_OK ==
+                  GNUNET_CONFIGURATION_get_value_string (cfg, serviceName,
+                                                         "BINDTO", &hostname));
+  }
+  else
+    hostname = NULL;
+
+  unixpath = NULL;
+#ifdef AF_UNIX
+  if ((GNUNET_YES ==
+       GNUNET_CONFIGURATION_have_value (cfg, serviceName, "UNIXPATH")) &&
+      (GNUNET_OK ==
+       GNUNET_CONFIGURATION_get_value_string (cfg, serviceName, "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,
+           sizeof (s_un.sun_path));
+      GNUNET_free_non_null (hostname);
+      GNUNET_free (unixpath);
+      return GNUNET_SYSERR;
+    }
+
+    desc = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0);
+    if (NULL == desc)
+    {
+      if ((errno == ENOBUFS) || (errno == ENOMEM) || (errno == ENFILE) ||
+          (errno == EACCES))
+      {
+        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "socket");
+        GNUNET_free_non_null (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"),
+           serviceName, STRERROR (errno));
+      GNUNET_free (unixpath);
+      unixpath = NULL;
+    }
+    else
+    {
+      GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (desc));
+      desc = NULL;
+    }
+  }
+#endif
+
+  if ((port == 0) && (unixpath == NULL))
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _
+         ("Have neither PORT nor UNIXPATH for service `%s', but one is required\n"),
+         serviceName);
+    GNUNET_free_non_null (hostname);
+    return GNUNET_SYSERR;
+  }
+  if (port == 0)
+  {
+    saddrs = GNUNET_malloc (2 * sizeof (struct sockaddr *));
+    saddrlens = GNUNET_malloc (2 * sizeof (socklen_t));
+    add_unixpath (saddrs, saddrlens, unixpath);
+    GNUNET_free_non_null (unixpath);
+    GNUNET_free_non_null (hostname);
+    *addrs = saddrs;
+    *addr_lens = saddrlens;
+    return 1;
+  }
+
+  if (hostname != NULL)
+  {
+#if DEBUG_SERVICE
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Resolving `%s' since that is where `%s' will bind to.\n", hostname,
+         serviceName);
+#endif
+    memset (&hints, 0, sizeof (struct addrinfo));
+    if (disablev6)
+      hints.ai_family = AF_INET;
+    if ((0 != (ret = getaddrinfo (hostname, NULL, &hints, &res))) ||
+        (res == NULL))
+    {
+      LOG (GNUNET_ERROR_TYPE_ERROR, _("Failed to resolve `%s': %s\n"), hostname,
+           gai_strerror (ret));
+      GNUNET_free (hostname);
+      GNUNET_free_non_null (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_non_null (unixpath);
+      return GNUNET_SYSERR;
+    }
+    resi = i;
+    if (NULL != unixpath)
+      resi++;
+    saddrs = GNUNET_malloc ((resi + 1) * sizeof (struct sockaddr *));
+    saddrlens = GNUNET_malloc ((resi + 1) * sizeof (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) && (pos->ai_family == AF_INET6))
+        continue;
+      if ((pos->ai_protocol != IPPROTO_TCP) && (pos->ai_protocol != 0))
+        continue;               /* not TCP */
+      if ((pos->ai_socktype != SOCK_STREAM) && (pos->ai_socktype != 0))
+        continue;               /* huh? */
+#if DEBUG_SERVICE
+      LOG (GNUNET_ERROR_TYPE_DEBUG, "Service `%s' will bind to `%s'\n",
+           serviceName, GNUNET_a2s (pos->ai_addr, pos->ai_addrlen));
+#endif
+      if (pos->ai_family == AF_INET)
+      {
+        GNUNET_assert (pos->ai_addrlen == sizeof (struct sockaddr_in));
+        saddrlens[i] = pos->ai_addrlen;
+        saddrs[i] = GNUNET_malloc (saddrlens[i]);
+        memcpy (saddrs[i], pos->ai_addr, saddrlens[i]);
+        ((struct sockaddr_in *) saddrs[i])->sin_port = htons (port);
+      }
+      else
+      {
+        GNUNET_assert (pos->ai_family == AF_INET6);
+        GNUNET_assert (pos->ai_addrlen == sizeof (struct sockaddr_in6));
+        saddrlens[i] = pos->ai_addrlen;
+        saddrs[i] = GNUNET_malloc (saddrlens[i]);
+        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_malloc ((resi + 1) * sizeof (struct sockaddr *));
+      saddrlens = GNUNET_malloc ((resi + 1) * sizeof (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_malloc ((resi + 1) * sizeof (struct sockaddr *));
+      saddrlens = GNUNET_malloc ((resi + 1) * sizeof (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_non_null (unixpath);
+  *addrs = saddrs;
+  *addr_lens = saddrlens;
+  return resi;
+}
+
+
+#ifdef MINGW
+/**
+ * @return GNUNET_YES if ok, GNUNET_NO if not ok (must bind yourself),
+ * and GNUNET_SYSERR on error.
+ */
+static int
+receive_sockets_from_parent (struct GNUNET_SERVICE_Context *sctx)
+{
+  const char *env_buf;
+  int fail;
+  uint64_t count, i;
+  HANDLE lsocks_pipe;
+
+  env_buf = getenv ("GNUNET_OS_READ_LSOCKS");
+  if ((env_buf == NULL) || (strlen (env_buf) <= 0))
+  {
+    return GNUNET_NO;
+  }
+  /* Using W32 API directly here, because this pipe will
+   * never be used outside of this function, and it's just too much of a bother
+   * to create a GNUnet API that boxes a HANDLE (the way it is done with socks)
+   */
+  lsocks_pipe = (HANDLE) strtoul (env_buf, NULL, 10);
+  if (lsocks_pipe == 0 || lsocks_pipe == INVALID_HANDLE_VALUE)
+    return GNUNET_NO;
+
+  fail = 1;
+  do
+  {
+    int ret;
+    int fail2;
+    DWORD rd;
+
+    ret = ReadFile (lsocks_pipe, &count, sizeof (count), &rd, NULL);
+    if (ret == 0 || rd != sizeof (count) || count == 0)
+      break;
+    sctx->lsocks =
+        GNUNET_malloc (sizeof (struct GNUNET_NETWORK_Handle *) * (count + 1));
+
+    fail2 = 1;
+    for (i = 0; i < count; i++)
+    {
+      WSAPROTOCOL_INFOA pi;
+      uint64_t size;
+      SOCKET s;
+      ret = ReadFile (lsocks_pipe, &size, sizeof (size), &rd, NULL);
+      if (ret == 0 || rd != sizeof (size) || size != sizeof (pi))
+        break;
+      ret = ReadFile (lsocks_pipe, &pi, sizeof (pi), &rd, NULL);
+      if (ret == 0 || rd != sizeof (pi))
+        break;
+      s = WSASocketA (pi.iAddressFamily, pi.iSocketType, pi.iProtocol, &pi, 0, WSA_FLAG_OVERLAPPED);
+      sctx->lsocks[i] = GNUNET_NETWORK_socket_box_native (s);
+      if (sctx->lsocks[i] == NULL)
+        break;
+      else if (i == count - 1)
+        fail2 = 0;
+    }
+    if (fail2)
+      break;
+    sctx->lsocks[count] = NULL;
+    fail = 0;
+  }
+  while (fail);
+
+  CloseHandle (lsocks_pipe);
+
+  if (fail)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _("Could not access a pre-bound socket, will try to bind myself\n"));
+    for (i = 0; i < count && sctx->lsocks[i] != NULL; i++)
+      GNUNET_break (0 == GNUNET_NETWORK_socket_close (sctx->lsocks[i]));
+    GNUNET_free_non_null (sctx->lsocks);
+    sctx->lsocks = NULL;
+    return GNUNET_NO;
+  }
+
+  return GNUNET_YES;
+}
+#endif
+
+
+/**
+ * Setup addr, addrlen, idle_timeout
+ * based on configuration!
+ *
+ * Configuration may specify:
+ * - PORT (where to bind to for TCP)
+ * - UNIXPATH (where to bind to for UNIX domain sockets)
+ * - TIMEOUT (after how many ms does an inactive service timeout);
+ * - DISABLEV6 (disable support for IPv6, otherwise we use dual-stack)
+ * - BINDTO (hostname or IP address to bind to, otherwise we take everything)
+ * - ACCEPT_FROM  (only allow connections from specified IPv4 subnets)
+ * - ACCEPT_FROM6 (only allow connections from specified IPv6 subnets)
+ * - REJECT_FROM  (disallow allow connections from specified IPv4 subnets)
+ * - REJECT_FROM6 (disallow allow connections from specified IPv6 subnets)
+ *
+ * @return GNUNET_OK if configuration succeeded
+ */
+static int
+setup_service (struct GNUNET_SERVICE_Context *sctx)
+{
+  struct GNUNET_TIME_Relative idleout;
+  int tolerant;
+
+#ifndef MINGW
+  const char *lpid;
+  unsigned int pid;
+  const char *nfds;
+  unsigned int cnt;
+  int flags;
+#endif
+
+  if (GNUNET_CONFIGURATION_have_value (sctx->cfg, sctx->serviceName, "TIMEOUT"))
+  {
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_time (sctx->cfg, sctx->serviceName,
+                                             "TIMEOUT", &idleout))
+    {
+      LOG (GNUNET_ERROR_TYPE_ERROR,
+           _("Specified value for `%s' of service `%s' is invalid\n"),
+           "TIMEOUT", sctx->serviceName);
+      return GNUNET_SYSERR;
+    }
+    sctx->timeout = idleout;
+  }
+  else
+    sctx->timeout = GNUNET_TIME_UNIT_FOREVER_REL;
+
+  if (GNUNET_CONFIGURATION_have_value
+      (sctx->cfg, sctx->serviceName, "TOLERANT"))
+  {
+    if (GNUNET_SYSERR ==
+        (tolerant =
+         GNUNET_CONFIGURATION_get_value_yesno (sctx->cfg, sctx->serviceName,
+                                               "TOLERANT")))
+    {
+      LOG (GNUNET_ERROR_TYPE_ERROR,
+           _("Specified value for `%s' of service `%s' is invalid\n"),
+           "TOLERANT", sctx->serviceName);
+      return GNUNET_SYSERR;
+    }
+  }
+  else
+    tolerant = GNUNET_NO;
+
+#ifndef MINGW
+  errno = 0;
+  if ((NULL != (lpid = getenv ("LISTEN_PID"))) &&
+      (1 == sscanf (lpid, "%u", &pid)) && (getpid () == (pid_t) pid) &&
+      (NULL != (nfds = getenv ("LISTEN_FDS"))) &&
+      (1 == sscanf (nfds, "%u", &cnt)) && (cnt > 0) && (cnt < FD_SETSIZE) &&
+      (cnt + 4 < FD_SETSIZE))
+  {
+    sctx->lsocks =
+        GNUNET_malloc (sizeof (struct GNUNET_NETWORK_Handle *) * (cnt + 1));
+    while (0 < cnt--)
+    {
+      flags = fcntl (3 + cnt, F_GETFD);
+      if ((flags < 0) || (0 != (flags & FD_CLOEXEC)) ||
+          (NULL ==
+           (sctx->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 (sctx->lsocks[cnt] != NULL)
+          GNUNET_break (0 == GNUNET_NETWORK_socket_close (sctx->lsocks[cnt++]));
+        GNUNET_free (sctx->lsocks);
+        sctx->lsocks = NULL;
+        break;
+      }
+    }
+    unsetenv ("LISTEN_PID");
+    unsetenv ("LISTEN_FDS");
+  }
+#else
+  if (getenv ("GNUNET_OS_READ_LSOCKS") != NULL)
+  {
+    receive_sockets_from_parent (sctx);
+    putenv ("GNUNET_OS_READ_LSOCKS=");
+  }
+#endif
+
+  if ((sctx->lsocks == NULL) &&
+      (GNUNET_SYSERR ==
+       GNUNET_SERVICE_get_server_addresses (sctx->serviceName, sctx->cfg,
+                                            &sctx->addrs, &sctx->addrlens)))
+    return GNUNET_SYSERR;
+  sctx->require_found = tolerant ? GNUNET_NO : GNUNET_YES;
+  sctx->match_uid =
+      GNUNET_CONFIGURATION_get_value_yesno (sctx->cfg, sctx->serviceName,
+                                            "UNIX_MATCH_UID");
+  sctx->match_gid =
+      GNUNET_CONFIGURATION_get_value_yesno (sctx->cfg, sctx->serviceName,
+                                            "UNIX_MATCH_GID");
+  process_acl4 (&sctx->v4_denied, sctx, "REJECT_FROM");
+  process_acl4 (&sctx->v4_allowed, sctx, "ACCEPT_FROM");
+  process_acl6 (&sctx->v6_denied, sctx, "REJECT_FROM6");
+  process_acl6 (&sctx->v6_allowed, sctx, "ACCEPT_FROM6");
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Get the name of the user that'll be used
+ * to provide the service.
+ */
+static char *
+get_user_name (struct GNUNET_SERVICE_Context *sctx)
+{
+
+  char *un;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_filename (sctx->cfg, sctx->serviceName,
+                                               "USERNAME", &un))
+    return NULL;
+  return un;
+}
+
+/**
+ * Write PID file.
+ */
+static int
+write_pid_file (struct GNUNET_SERVICE_Context *sctx, pid_t pid)
+{
+  FILE *pidfd;
+  char *pif;
+  char *user;
+  char *rdir;
+  int len;
+
+  if (NULL == (pif = get_pid_file_name (sctx)))
+    return GNUNET_OK;           /* no file desired */
+  user = get_user_name (sctx);
+  rdir = GNUNET_strdup (pif);
+  len = strlen (rdir);
+  while ((len > 0) && (rdir[len] != DIR_SEPARATOR))
+    len--;
+  rdir[len] = '\0';
+  if (0 != ACCESS (rdir, F_OK))
+  {
+    /* we get to create a directory -- and claim it
+     * as ours! */
+    GNUNET_DISK_directory_create (rdir);
+    if ((user != NULL) && (0 < strlen (user)))
+      GNUNET_DISK_file_change_owner (rdir, user);
+  }
+  if (0 != ACCESS (rdir, W_OK | X_OK))
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "access", rdir);
+    GNUNET_free (rdir);
+    GNUNET_free_non_null (user);
+    GNUNET_free (pif);
+    return GNUNET_SYSERR;
+  }
+  GNUNET_free (rdir);
+  pidfd = FOPEN (pif, "w");
+  if (pidfd == NULL)
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "fopen", pif);
+    GNUNET_free (pif);
+    GNUNET_free_non_null (user);
+    return GNUNET_SYSERR;
+  }
+  if (0 > FPRINTF (pidfd, "%u", pid))
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "fprintf", pif);
+  GNUNET_break (0 == FCLOSE (pidfd));
+  if ((user != NULL) && (0 < strlen (user)))
+    GNUNET_DISK_file_change_owner (pif, user);
+  GNUNET_free_non_null (user);
+  GNUNET_free (pif);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Task run during shutdown.
+ *
+ * @param cls unused
+ * @param tc unused
+ */
+static void
+shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_SERVER_Handle *server = cls;
+
+  GNUNET_SERVER_destroy (server);
+}
+
+
+/**
+ * Initial task for the service.
+ */
+static void
+service_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_SERVICE_Context *sctx = cls;
+  unsigned int i;
+
+  GNUNET_RESOLVER_connect (sctx->cfg);
+  if (sctx->lsocks != NULL)
+    sctx->server =
+        GNUNET_SERVER_create_with_sockets (&check_access, sctx, sctx->lsocks,
+                                           sctx->timeout, sctx->require_found);
+  else
+    sctx->server =
+        GNUNET_SERVER_create (&check_access, sctx, sctx->addrs, sctx->addrlens,
+                              sctx->timeout, sctx->require_found);
+  if (sctx->server == NULL)
+  {
+    if (sctx->addrs != NULL)
+    {
+      i = 0;
+      while (sctx->addrs[i] != NULL)
+      {
+        LOG (GNUNET_ERROR_TYPE_INFO, _("Failed to start `%s' at `%s'\n"),
+             sctx->serviceName, GNUNET_a2s (sctx->addrs[i], sctx->addrlens[i]));
+        i++;
+      }
+    }
+    sctx->ret = GNUNET_SYSERR;
+    return;
+  }
+  if (0 == (sctx->options & GNUNET_SERVICE_OPTION_MANUAL_SHUTDOWN))
+  {
+    /* install a task that will kill the server
+     * process if the scheduler ever gets a shutdown signal */
+    GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
+                                  sctx->server);
+  }
+  sctx->my_handlers = GNUNET_malloc (sizeof (defhandlers));
+  memcpy (sctx->my_handlers, defhandlers, sizeof (defhandlers));
+  i = 0;
+  while ((sctx->my_handlers[i].callback != NULL))
+    sctx->my_handlers[i++].callback_cls = sctx;
+  GNUNET_SERVER_add_handlers (sctx->server, sctx->my_handlers);
+  if (sctx->ready_confirm_fd != -1)
+  {
+    GNUNET_break (1 == WRITE (sctx->ready_confirm_fd, ".", 1));
+    GNUNET_break (0 == CLOSE (sctx->ready_confirm_fd));
+    sctx->ready_confirm_fd = -1;
+    write_pid_file (sctx, getpid ());
+  }
+  if (sctx->addrs != NULL)
+  {
+    i = 0;
+    while (sctx->addrs[i] != NULL)
+    {
+      LOG (GNUNET_ERROR_TYPE_INFO, _("Service `%s' runs at %s\n"),
+           sctx->serviceName, GNUNET_a2s (sctx->addrs[i], sctx->addrlens[i]));
+      i++;
+    }
+  }
+  sctx->task (sctx->task_cls, sctx->server, sctx->cfg);
+}
+
+
+/**
+ * Detach from terminal.
+ */
+static int
+detach_terminal (struct GNUNET_SERVICE_Context *sctx)
+{
+#ifndef MINGW
+  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 (pid != 0)
+  {
+    /* 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 (pid == -1)
+    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "setsid");
+  sctx->ready_confirm_fd = filedes[1];
+#else
+  /* FIXME: we probably need to do something else
+   * elsewhere in order to fork the process itself... */
+  FreeConsole ();
+#endif
+  return GNUNET_OK;
+}
+
+
+/**
+ * Set user ID.
+ */
+static int
+set_user_id (struct GNUNET_SERVICE_Context *sctx)
+{
+  char *user;
+
+  if (NULL == (user = get_user_name (sctx)))
+    return GNUNET_OK;           /* keep */
+#ifndef MINGW
+  struct passwd *pws;
+
+  errno = 0;
+  pws = getpwnam (user);
+  if (pws == NULL)
+  {
+    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;
+    }
+  }
+#endif
+  GNUNET_free (user);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Delete the PID file that was created by our parent.
+ */
+static void
+pid_file_delete (struct GNUNET_SERVICE_Context *sctx)
+{
+  char *pif = get_pid_file_name (sctx);
+
+  if (pif == NULL)
+    return;                     /* no PID file */
+  if (0 != UNLINK (pif))
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "unlink", pif);
+  GNUNET_free (pif);
+}
+
+
+/**
+ * Run a standard GNUnet service startup sequence (initialize loggers
+ * and configuration, parse options).
+ *
+ * @param argc number of command line arguments
+ * @param argv command line arguments
+ * @param serviceName our service name
+ * @param opt service options
+ * @param task main task of the service
+ * @param task_cls closure for task
+ * @return GNUNET_SYSERR on error, GNUNET_OK
+ *         if we shutdown nicely
+ */
+int
+GNUNET_SERVICE_run (int argc, char *const *argv, const char *serviceName,
+                    enum GNUNET_SERVICE_Options opt, GNUNET_SERVICE_Main task,
+                    void *task_cls)
+{
+#define HANDLE_ERROR do { GNUNET_break (0); goto shutdown; } while (0)
+
+  int err;
+  char *cfg_fn;
+  char *loglev;
+  char *logfile;
+  int do_daemonize;
+  unsigned int i;
+  unsigned long long skew_offset;
+  unsigned long long skew_variance;
+  long long clock_offset;
+  struct GNUNET_SERVICE_Context sctx;
+  struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  struct GNUNET_GETOPT_CommandLineOption service_options[] = {
+    GNUNET_GETOPT_OPTION_CFG_FILE (&cfg_fn),
+    {'d', "daemonize", NULL,
+     gettext_noop ("do daemonize (detach from terminal)"), 0,
+     GNUNET_GETOPT_set_one, &do_daemonize},
+    GNUNET_GETOPT_OPTION_HELP (serviceName),
+    GNUNET_GETOPT_OPTION_LOGLEVEL (&loglev),
+    GNUNET_GETOPT_OPTION_LOGFILE (&logfile),
+    GNUNET_GETOPT_OPTION_VERSION (PACKAGE_VERSION),
+    GNUNET_GETOPT_OPTION_END
+  };
+  err = 1;
+  do_daemonize = 0;
+  logfile = NULL;
+  loglev = NULL;
+  cfg_fn = GNUNET_strdup (GNUNET_DEFAULT_USER_CONFIG_FILE);
+  memset (&sctx, 0, sizeof (sctx));
+  sctx.options = opt;
+  sctx.ready_confirm_fd = -1;
+  sctx.ret = GNUNET_OK;
+  sctx.timeout = GNUNET_TIME_UNIT_FOREVER_REL;
+  sctx.task = task;
+  sctx.task_cls = task_cls;
+  sctx.serviceName = serviceName;
+  sctx.cfg = cfg = GNUNET_CONFIGURATION_create ();
+  /* setup subsystems */
+  if (GNUNET_SYSERR ==
+      GNUNET_GETOPT_run (serviceName, service_options, argc, argv))
+    goto shutdown;
+  if (GNUNET_OK != GNUNET_log_setup (serviceName, loglev, logfile))
+    HANDLE_ERROR;
+  if (GNUNET_OK != GNUNET_CONFIGURATION_load (cfg, cfg_fn))
+    goto shutdown;
+  if (GNUNET_OK != setup_service (&sctx))
+    goto shutdown;
+  if ((do_daemonize == 1) && (GNUNET_OK != detach_terminal (&sctx)))
+    HANDLE_ERROR;
+  if (GNUNET_OK != set_user_id (&sctx))
+    goto shutdown;
+#if DEBUG_SERVICE
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Service `%s' runs with configuration from `%s'\n", serviceName, cfg_fn);
+#endif
+  if ((GNUNET_OK ==
+       GNUNET_CONFIGURATION_get_value_number (sctx.cfg, "TESTING",
+                                              "SKEW_OFFSET", &skew_offset)) &&
+      (GNUNET_OK ==
+       GNUNET_CONFIGURATION_get_value_number (sctx.cfg, "TESTING",
+                                              "SKEW_VARIANCE", &skew_variance)))
+  {
+    clock_offset = skew_offset - skew_variance;
+    GNUNET_TIME_set_offset (clock_offset);
+#if DEBUG_SERVICE
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Skewing clock by %dll ms\n", clock_offset);
+#endif
+  }
+  /* actually run service */
+  err = 0;
+  GNUNET_SCHEDULER_run (&service_task, &sctx);
+
+  /* shutdown */
+  if ((do_daemonize == 1) && (sctx.server != NULL))
+    pid_file_delete (&sctx);
+  GNUNET_free_non_null (sctx.my_handlers);
+
+shutdown:
+  if (sctx.ready_confirm_fd != -1)
+  {
+    if (1 != WRITE (sctx.ready_confirm_fd, err ? "I" : "S", 1))
+      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "write");
+    GNUNET_break (0 == CLOSE (sctx.ready_confirm_fd));
+  }
+
+  GNUNET_CONFIGURATION_destroy (cfg);
+  i = 0;
+  if (sctx.addrs != NULL)
+    while (sctx.addrs[i] != NULL)
+      GNUNET_free (sctx.addrs[i++]);
+  GNUNET_free_non_null (sctx.addrs);
+  GNUNET_free_non_null (sctx.addrlens);
+  GNUNET_free_non_null (logfile);
+  GNUNET_free_non_null (loglev);
+  GNUNET_free (cfg_fn);
+  GNUNET_free_non_null (sctx.v4_denied);
+  GNUNET_free_non_null (sctx.v6_denied);
+  GNUNET_free_non_null (sctx.v4_allowed);
+  GNUNET_free_non_null (sctx.v6_allowed);
+
+  return err ? GNUNET_SYSERR : sctx.ret;
+}
+
+
+/**
+ * Run a service startup sequence within an existing
+ * initialized system.
+ *
+ * @param serviceName our service name
+ * @param cfg configuration to use
+ * @return NULL on error, service handle
+ */
+struct GNUNET_SERVICE_Context *
+GNUNET_SERVICE_start (const char *serviceName,
+                      const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  int i;
+  struct GNUNET_SERVICE_Context *sctx;
+
+  sctx = GNUNET_malloc (sizeof (struct GNUNET_SERVICE_Context));
+  sctx->ready_confirm_fd = -1;  /* no daemonizing */
+  sctx->ret = GNUNET_OK;
+  sctx->timeout = GNUNET_TIME_UNIT_FOREVER_REL;
+  sctx->serviceName = serviceName;
+  sctx->cfg = cfg;
+
+  /* setup subsystems */
+  if (GNUNET_OK != setup_service (sctx))
+  {
+    GNUNET_SERVICE_stop (sctx);
+    return NULL;
+  }
+  if (sctx->lsocks != NULL)
+    sctx->server =
+        GNUNET_SERVER_create_with_sockets (&check_access, sctx, sctx->lsocks,
+                                           sctx->timeout, sctx->require_found);
+  else
+    sctx->server =
+        GNUNET_SERVER_create (&check_access, sctx, sctx->addrs, sctx->addrlens,
+                              sctx->timeout, sctx->require_found);
+
+  if (NULL == sctx->server)
+  {
+    GNUNET_SERVICE_stop (sctx);
+    return NULL;
+  }
+  sctx->my_handlers = GNUNET_malloc (sizeof (defhandlers));
+  memcpy (sctx->my_handlers, defhandlers, sizeof (defhandlers));
+  i = 0;
+  while ((sctx->my_handlers[i].callback != NULL))
+    sctx->my_handlers[i++].callback_cls = sctx;
+  GNUNET_SERVER_add_handlers (sctx->server, sctx->my_handlers);
+  return sctx;
+}
+
+/**
+ * Obtain the server used by a service.  Note that the server must NOT
+ * be destroyed by the caller.
+ *
+ * @param ctx the service context returned from the start function
+ * @return handle to the server for this service, NULL if there is none
+ */
+struct GNUNET_SERVER_Handle *
+GNUNET_SERVICE_get_server (struct GNUNET_SERVICE_Context *ctx)
+{
+  return ctx->server;
+}
+
+
+/**
+ * Stop a service that was started with "GNUNET_SERVICE_start".
+ *
+ * @param sctx the service context returned from the start function
+ */
+void
+GNUNET_SERVICE_stop (struct GNUNET_SERVICE_Context *sctx)
+{
+  unsigned int i;
+
+  if (NULL != sctx->server)
+    GNUNET_SERVER_destroy (sctx->server);
+  GNUNET_free_non_null (sctx->my_handlers);
+  if (sctx->addrs != NULL)
+  {
+    i = 0;
+    while (sctx->addrs[i] != NULL)
+      GNUNET_free (sctx->addrs[i++]);
+    GNUNET_free (sctx->addrs);
+  }
+  GNUNET_free_non_null (sctx->addrlens);
+  GNUNET_free_non_null (sctx->v4_denied);
+  GNUNET_free_non_null (sctx->v6_denied);
+  GNUNET_free_non_null (sctx->v4_allowed);
+  GNUNET_free_non_null (sctx->v6_allowed);
+  GNUNET_free (sctx);
+}
+
+
+/* end of service.c */