X-Git-Url: http://www.project-moonshot.org/gitweb/?p=trust_router.git;a=blobdiff_plain;f=tid%2Ftids.c;h=05693336c5d925a85739d695704eba600c146ad8;hp=202c62a15589da0928596ee0eae06ee12b2bcbf8;hb=6454056a45ff204133fd53f7f147e46ffb397d4f;hpb=5e8a6048b40aa6cf9ade2bf3f1a6834947fda308

diff --git a/tid/tids.c b/tid/tids.c
index 202c62a..0569333 100644
--- a/tid/tids.c
+++ b/tid/tids.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, JANET(UK)
+ * Copyright (c) 2012, 2015, JANET(UK)
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -34,262 +34,598 @@
 
 #include <stdlib.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <string.h>
 #include <stdio.h>
-#include <errno.h>
 #include <sys/socket.h>
-#include <netinet/in.h>
+#include <sys/wait.h>
 #include <jansson.h>
-
-#include <trust_router/tid.h>
+#include <talloc.h>
+#include <poll.h>
+#include <tid_internal.h>
 #include <gsscon.h>
+#include <tr_debug.h>
 #include <tr_msg.h>
+#include <tr_socket.h>
+#include <tr_gss.h>
+#include <tr_event.h>
 
-static int tids_listen (TIDS_INSTANCE *tids, int port) 
+/**
+ * Create a response with minimal fields filled in
+ *
+ * @param mem_ctx talloc context for the return value
+ * @param req request to respond to
+ * @return new response structure allocated in the mem_ctx context
+ */
+static TID_RESP *tids_create_response(TALLOC_CTX *mem_ctx, TID_REQ *req)
 {
-    int rc = 0;
-    int conn = -1;
-    struct sockaddr_storage addr;
-    struct sockaddr_in *saddr = (struct sockaddr_in *) &addr;
-    
-    saddr->sin_port = htons (port);
-    saddr->sin_family = AF_INET;
-    saddr->sin_addr.s_addr = INADDR_ANY;
-
-    if (0 > (conn = socket (AF_INET, SOCK_STREAM, 0)))
-      return conn;
-        
-    if (0 > (rc = bind (conn, (struct sockaddr *) saddr, sizeof(struct sockaddr_in))))
-      return rc;
-        
-    if (0 > (rc = listen(conn, 512)))
-      return rc;
+  TID_RESP *resp=NULL;
+  int success=0;
+
+  if (NULL == (resp = tid_resp_new(mem_ctx))) {
+    tr_crit("tids_create_response: Error allocating response structure.");
+    return NULL;
+  }
+  
+  resp->result = TID_SUCCESS; /* presume success */
+  if ((NULL == (resp->rp_realm = tr_dup_name(req->rp_realm))) ||
+      (NULL == (resp->realm = tr_dup_name(req->realm))) ||
+      (NULL == (resp->comm = tr_dup_name(req->comm)))) {
+    tr_crit("tids_create_response: Error allocating fields in response.");
+    goto cleanup;
+  }
+  if (req->orig_coi) {
+    if (NULL == (resp->orig_coi = tr_dup_name(req->orig_coi))) {
+      tr_crit("tids_create_response: Error allocating fields in response.");
+      goto cleanup;
+    }
+  }
+  if (req->request_id) {
+    if (NULL == (resp->request_id = tr_dup_name(req->request_id))) {
+      tr_crit("tids_create_response: Error allocating fields in response.");
+      goto cleanup;
+    }
+  }
+
+  success=1;
+
+cleanup:
+  if ((!success) && (resp!=NULL)) {
+    talloc_free(resp);
+    resp=NULL;
+  }
+  return resp;
+}
+
+static int tids_handle_request(TIDS_INSTANCE *tids, TID_REQ *req, TID_RESP *resp)
+{
+  int rc=-1;
+
+  /* Check that this is a valid TID Request.  If not, send an error return. */
+  if ((!req) ||
+      (!(req->rp_realm)) ||
+      (!(req->realm)) ||
+      (!(req->comm))) {
+    tr_notice("tids_handle_request(): Not a valid TID Request.");
+    tid_resp_set_result(resp, TID_ERROR);
+    tid_resp_set_err_msg(resp, tr_new_name("Bad request format"));
+    return -1;
+  }
+
+  tr_debug("tids_handle_request: adding self to req path.");
+  tid_req_add_path(req, tids->hostname, tids->tids_port);
+  
+  /* Call the caller's request handler */
+  /* TBD -- Handle different error returns/msgs */
+  if (0 > (rc = (*tids->req_handler)(tids, req, resp, tids->cookie))) {
+    /* set-up an error response */
+    tr_debug("tids_handle_request: req_handler returned error.");
+    tid_resp_set_result(resp, TID_ERROR);
+    if (!tid_resp_get_err_msg(resp))	/* Use msg set by handler, if any */
+      tid_resp_set_err_msg(resp, tr_new_name("Internal processing error"));
+  } else {
+    /* set-up a success response */
+    tr_debug("tids_handle_request: req_handler returned success.");
+    tid_resp_set_result(resp, TID_SUCCESS);
+    resp->err_msg = NULL;	/* No error msg on successful return */
+  }
     
-    fprintf (stdout, "TID Server listening on port %d\n", port);
-    return conn; 
+  return rc;
 }
 
-static int tids_auth_connection (int conn, gss_ctx_id_t *gssctx)
+/**
+ * Produces a JSON-encoded msg containing the TID response
+ *
+ * @param mem_ctx talloc context for the return value
+ * @param resp outgoing response
+ * @return JSON-encoded message containing the TID response
+ */
+static char *tids_encode_response(TALLOC_CTX *mem_ctx, TID_RESP *resp)
 {
+  TR_MSG mresp;
+  char *resp_buf = NULL;
+
+  /* Construct the response message */
+  mresp.msg_type = TID_RESPONSE;
+  tr_msg_set_resp(&mresp, resp);
+
+  /* Encode the message to JSON */
+  resp_buf = tr_msg_encode(mem_ctx, &mresp);
+  if (resp_buf == NULL) {
+    tr_err("tids_encode_response: Error encoding json response.");
+    return NULL;
+  }
+  tr_debug("tids_encode_response: Encoded response: %s", resp_buf);
+
+  /* Success */
+  return resp_buf;
+}
+
+/**
+ * Encode/send an error response
+ *
+ * Part of the public interface
+ *
+ * @param tids
+ * @param req
+ * @param err_msg
+ * @return
+ */
+int tids_send_err_response (TIDS_INSTANCE *tids, TID_REQ *req, const char *err_msg) {
+  TID_RESP *resp = NULL;
   int rc = 0;
-  int auth, autherr = 0;
 
-  if (rc = gsscon_passive_authenticate(conn, gssctx)) {
-    fprintf(stderr, "Error from gsscon_passive_authenticate(), rc = %d.\n", rc);
+  if ((!tids) || (!req) || (!err_msg)) {
+    tr_debug("tids_send_err_response: Invalid parameters.");
     return -1;
   }
 
-  if (rc = gsscon_authorize(*gssctx, &auth, &autherr)) {
-    fprintf(stderr, "Error from gsscon_authorize, rc = %d, autherr = %d.\n", 
-	    rc, autherr);
+  /* If we already sent a response, don't send another no matter what. */
+  if (req->resp_sent)
+    return 0;
+
+  if (NULL == (resp = tids_create_response(req, req))) {
+    tr_crit("tids_send_err_response: Can't create response.");
     return -1;
   }
 
-  if (auth)
-    fprintf(stdout, "Connection authenticated, conn = %d.\n", conn);
-  else
-    fprintf(stderr, "Authentication failed, conn %d.\n", conn);
+  /* mark this as an error response, and include the error message */
+  resp->result = TID_ERROR;
+  resp->err_msg = tr_new_name((char *)err_msg);
+  resp->error_path = req->path;
+
+  rc = tids_send_response(tids, req, resp);
 
-  return !auth;
+  tid_resp_free(resp);
+  return rc;
 }
 
-static int tids_read_request (TIDS_INSTANCE *tids, int conn, gss_ctx_id_t *gssctx, TR_MSG **mreq)
+/**
+ * Encode/send a response
+ *
+ * Part of the public interface
+ *
+ * @param tids not actually used, but kept for ABI compatibility
+ * @param req
+ * @param resp
+ * @return
+ */
+int tids_send_response (TIDS_INSTANCE *tids, TID_REQ *req, TID_RESP *resp)
 {
   int err;
-  char *buf;
-  size_t buflen = 0;
+  char *resp_buf;
 
-  if (err = gsscon_read_encrypted_token(conn, *gssctx, &buf, &buflen)) {
-    if (buf)
-      free(buf);
+  if ((!tids) || (!req) || (!resp)) {
+    tr_debug("tids_send_response: Invalid parameters.");
     return -1;
   }
 
-  fprintf(stdout, "tids_read_request():Request Received, %d bytes.\n", buflen);
+  /* Never send a second response if we already sent one. */
+  if (req->resp_sent)
+    return 0;
 
-  /* Parse request */
-  if (NULL == ((*mreq) = tr_msg_decode(buf, buflen))) {
-    printf("tids_read_request():Error decoding request.\n");
-    free (buf);
+  resp_buf = tids_encode_response(NULL, NULL);
+  if (resp_buf == NULL) {
+    tr_err("tids_send_response: Error encoding json response.");
+    tr_audit_req(req);
     return -1;
   }
 
-  /* If this isn't a TID Request, just drop it. */
-  if (TID_REQUEST != (*mreq)->msg_type) {
-    printf("tids_read_request(): Not a TID Request, dropped.\n");
+  tr_debug("tids_send_response: Encoded response: %s", resp_buf);
+
+  /* If external logging is enabled, fire off a message */
+  /* TODO Can be moved to end once segfault in gsscon_write_encrypted_token fixed */
+  tr_audit_resp(resp);
+
+  /* Send the response over the connection */
+  err = gsscon_write_encrypted_token (req->conn, req->gssctx, resp_buf,
+                                            strlen(resp_buf) + 1);
+  if (err) {
+    tr_notice("tids_send_response: Error sending response over connection.");
+    tr_audit_req(req);
     return -1;
   }
 
-  free (buf);
-  return buflen;
+  /* indicate that a response has been sent for this request */
+  req->resp_sent = 1;
+
+  free(resp_buf);
+
+  return 0;
 }
 
-static int tids_handle_request (TIDS_INSTANCE *tids, TR_MSG *mreq, TID_RESP **resp) 
+/**
+ * Callback to process a request and produce a response
+ *
+ * @param req_str JSON-encoded request
+ * @param data pointer to a TIDS_INSTANCE
+ * @return pointer to the response string or null to send no response
+ */
+static TR_MSG *tids_req_cb(TALLOC_CTX *mem_ctx, TR_MSG *mreq, void *data)
 {
-  int rc;
+  TALLOC_CTX *tmp_ctx = talloc_new(NULL);
+  TIDS_INSTANCE *tids = talloc_get_type_abort(data, TIDS_INSTANCE);
+  TID_REQ *req = NULL;
+  TID_RESP *resp = NULL;
+  TR_MSG *resp_msg = NULL; /* this is the return value */
+  int rc = 0;
 
-  /* Check that this is a valid TID Request.  If not, send an error return. */
-  if ((!mreq->tid_req) ||
-      (!mreq->tid_req->rp_realm) ||
-      (!mreq->tid_req->realm) ||
-      (!mreq->tid_req->comm)) {
-    printf("tids_handle_request():Not a valid TID Request.\n");
-    (*resp)->result = TID_ERROR;
-    (*resp)->err_msg = tr_new_name("Bad request format");
-    return -1;
+  /* If this isn't a TID Request, just drop it. */
+  if (mreq->msg_type != TID_REQUEST) {
+    tr_debug("tids_req_cb: Not a TID request, dropped.");
+    goto cleanup;
   }
 
-  /* Call the caller's request handler */
-  /* TBD -- Handle different error returns/msgs */
-  if (0 > (rc = (*tids->req_handler)(tids, mreq->tid_req, &(*resp), tids->cookie))) {
-    /* set-up an error response */
-    (*resp)->result = TID_ERROR;
-    if (!(*resp)->err_msg)	/* Use msg set by handler, if any */
-      (*resp)->err_msg = tr_new_name("Internal processing error");
+  /* Get a handle on the request itself. Don't free req - it belongs to mreq */
+  req = tr_msg_get_req(mreq);
+
+  /* Allocate a response message */
+  resp_msg = talloc(tmp_ctx, TR_MSG);
+  if (resp_msg == NULL) {
+    /* We cannot create a response message, so all we can really do is emit
+     * an error message and return. */
+    tr_crit("tids_req_cb: Error allocating response message.");
+    goto cleanup;
   }
-  else {
-    /* set-up a success response */
-    (*resp)->result = TID_SUCCESS;
-    (*resp)->err_msg = NULL;	/* No msg on successful return */
+
+  /* Allocate a response structure and populate common fields. Put it in the
+   * response message's talloc context. */
+  resp = tids_create_response(resp_msg, req);
+  if (resp == NULL) {
+    /* If we were unable to create a response, we cannot reply. Log an
+     * error if we can, then drop the request. */
+    tr_crit("tids_req_cb: Error creating response structure.");
+    resp_msg = NULL; /* the contents are in tmp_ctx, so they will still be cleaned up */
+    goto cleanup;
   }
-    
-  return rc;
+  /* Now officially assign the response to the message. */
+  tr_msg_set_resp(resp_msg, resp);
+
+  /* Handle the request and fill in resp */
+  rc = tids_handle_request(tids, req, resp);
+  if (rc < 0) {
+    tr_debug("tids_req_cb: Error from tids_handle_request(), rc = %d.", rc);
+    /* Fall through, to send the response, either way */
+  }
+
+  /* put the response message in the caller's context */
+  talloc_steal(mem_ctx, resp_msg);
+
+cleanup:
+  talloc_free(tmp_ctx);
+  return resp_msg;
 }
 
-int tids_send_response (TIDS_INSTANCE *tids, int conn, gss_ctx_id_t *gssctx, TID_RESP *resp)
+static int tids_destructor(void *object)
 {
-  int err;
-  TR_MSG mresp;
-  char *resp_buf;
+  TIDS_INSTANCE *tids = talloc_get_type_abort(object, TIDS_INSTANCE);
+  if (tids->pids)
+    g_array_unref(tids->pids);
+  return 0;
+}
 
-  mresp.msg_type = TID_RESPONSE;
-  mresp.tid_resp = resp;
-  
-  if (NULL == (resp_buf = tr_msg_encode(&mresp))) {
-    fprintf(stderr, "Error decoding json response.\n");
-    return -1;
+TIDS_INSTANCE *tids_new(TALLOC_CTX *mem_ctx)
+{
+  TIDS_INSTANCE *tids = talloc_zero(mem_ctx, TIDS_INSTANCE);
+  if (tids) {
+    tids->pids = g_array_new(FALSE, FALSE, sizeof(struct tid_process));
+    if (tids->pids == NULL) {
+      talloc_free(tids);
+      return NULL;
+    }
+    talloc_set_destructor((void *)tids, tids_destructor);
   }
+  return tids;
+}
 
-  printf("Encoded response:\n%s\n", resp_buf);
-  
-  /* Send the response over the connection */
-  if (err = gsscon_write_encrypted_token (conn, *gssctx, resp_buf, 
-					  strlen(resp_buf) + 1)) {
-    fprintf(stderr, "Error sending response over connection.\n");
-    return -1;
+/**
+ * Create a new TIDS instance
+ *
+ * Deprecated: exists for ABI compatibility, but tids_new() should be used instead
+ *
+ */
+TIDS_INSTANCE *tids_create(void)
+{
+  return tids_new(NULL);
+}
+
+/* Get a listener for tids requests, returns its socket fd. Accept
+ * connections with tids_accept() */
+nfds_t tids_get_listener(TIDS_INSTANCE *tids,
+                         TIDS_REQ_FUNC *req_handler,
+                         tids_auth_func *auth_handler,
+                         const char *hostname,
+                         unsigned int port,
+                         void *cookie,
+                         int *fd_out,
+                         size_t max_fd)
+{
+  nfds_t n_fd = 0;
+  nfds_t ii = 0;
+
+  tids->tids_port = port;
+  n_fd = tr_sock_listen_all(port, fd_out, max_fd);
+
+  if (n_fd == 0)
+    tr_err("tids_get_listener: Error opening port %d");
+  else {
+    /* opening port succeeded */
+    tr_info("tids_get_listener: Opened port %d.", port);
+    
+    /* make this socket non-blocking */
+    for (ii=0; ii<n_fd; ii++) {
+      if (0 != fcntl(fd_out[ii], F_SETFL, O_NONBLOCK)) {
+        tr_err("tids_get_listener: Error setting O_NONBLOCK.");
+        for (ii=0; ii<n_fd; ii++) {
+          close(fd_out[ii]);
+          fd_out[ii]=-1;
+        }
+        n_fd = 0;
+        break;
+      }
+    }
   }
 
-  free(resp_buf);
+  if (n_fd > 0) {
+    /* store the caller's request handler & cookie */
+    tids->req_handler = req_handler;
+    tids->auth_handler = auth_handler;
+    tids->hostname = hostname;
+    tids->cookie = cookie;
+  }
 
-  return 0;
+  return (int)n_fd;
+}
+
+/* Strings used to report results from the handler process. The
+ * TIDS_MAX_MESSAGE_LEN must be longer than the longest message, including
+ * null termination (i.e., strlen() + 1) */
+#define TIDS_MAX_MESSAGE_LEN (10)
+#define TIDS_SUCCESS_MESSAGE "OK"
+#define TIDS_ERROR_MESSAGE   "ERR"
+
+/**
+ * Process to handle an incoming TIDS request
+ *
+ * This should be run in the child process after a fork(). Handles
+ * the request, writes the result to result_fd, and terminates via exit().
+ * Never returns to the caller.
+ *
+ * @param tids TID server instance
+ * @param conn_fd file descriptor for the incoming connection
+ * @param result_fd writable file descriptor for the result, or 0 to disable reporting
+ */
+static void tids_handle_proc(TIDS_INSTANCE *tids, int conn_fd, int result_fd)
+{
+  const char *response_message = NULL;
+
+  switch(tr_gss_handle_connection(conn_fd,
+                                  "trustidentity", tids->hostname, /* acceptor name */
+                                  tids->auth_handler, tids->cookie, /* auth callback and cookie */
+                                  tids_req_cb, tids /* req callback and cookie */
+  )) {
+    case TR_GSS_SUCCESS:
+      response_message = TIDS_SUCCESS_MESSAGE;
+      break;
+
+    case TR_GSS_ERROR:
+    default:
+      response_message = TIDS_ERROR_MESSAGE;
+      break;
+  }
+
+  if (0 != result_fd) {
+    /* write strlen + 1 to include the null termination */
+    if (write(result_fd, response_message, strlen(response_message) + 1) < 0)
+      tr_err("tids_accept: child process unable to write to pipe");
+  }
+
+  close(result_fd);
+  close(conn_fd);
+  exit(0); /* exit to kill forked child process */
 }
 
-static void tids_handle_connection (TIDS_INSTANCE *tids, int conn)
+/* Accept and process a connection on a port opened with tids_get_listener() */
+int tids_accept(TIDS_INSTANCE *tids, int listen)
 {
-  TR_MSG *mreq = NULL;
-  TID_RESP *resp = NULL;
-  int rc = 0;
-  gss_ctx_id_t gssctx = GSS_C_NO_CONTEXT;
+  int conn=-1;
+  int pid=-1;
+  int pipe_fd[2];
+  struct tid_process tp = {0};
+
+  if (0 > (conn = tr_sock_accept(listen))) {
+    tr_err("tids_accept: Error accepting connection");
+    return 1;
+  }
 
-  if (tids_auth_connection(conn, &gssctx)) {
-    fprintf(stderr, "Error authorizing TID Server connection.\n");
-    close(conn);
-    return;
+  if (0 > pipe(pipe_fd)) {
+    perror("Error on pipe()");
+    return 1;
   }
+  /* pipe_fd[0] is for reading, pipe_fd[1] is for writing */
 
-  printf("Connection authorized!\n");
+  if (0 > (pid = fork())) {
+    perror("Error on fork()");
+    return 1;
+  }
 
-  while (1) {	/* continue until an error breaks us out */
+  if (pid == 0) {
+    /* Only the child process gets here */
+    close(pipe_fd[0]); /* close the read end of the pipe, the child only writes */
+    close(listen); /* close the child process's handle on the listen port */
 
-    if (0 > (rc = tids_read_request(tids, conn, &gssctx, &mreq))) {
-      fprintf(stderr, "Error from tids_read_request(), rc = %d.\n", rc);
-      return;
-    } else if (0 == rc) {
-      continue;
-    }
+    tids_handle_proc(tids, conn, pipe_fd[1]); /* never returns */
+  }
 
-    /* Allocate a response structure and populate common fields */
-    if ((NULL == (resp = calloc(sizeof(TID_RESP), 1)))) {
-      fprintf(stderr, "Error allocating response structure.\n");
-      return;
-    }
+  /* Only the parent process gets here */
+  close(pipe_fd[1]); /* close the write end of the pipe, the parent only listens */
+  close(conn); /* connection belongs to the child, so close parent's handle */
+
+  /* remember the PID of our child process */
+  tr_info("tids_accept: Spawned TID process %d to handle incoming connection.", pid);
+  tp.pid = pid;
+  tp.read_fd = pipe_fd[0];
+  g_array_append_val(tids->pids, tp);
 
-    /* TBD -- handle errors */
-    resp->result = TID_SUCCESS; /* presume success */
-    resp->rp_realm = tr_dup_name(mreq->tid_req->rp_realm);
-    resp->realm = tr_dup_name(mreq->tid_req->realm);
-    resp->comm = tr_dup_name(mreq->tid_req->comm);
-    if (mreq->tid_req->orig_coi)
-      resp->orig_coi = tr_dup_name(mreq->tid_req->orig_coi);
-
-    if (0 > (rc = tids_handle_request(tids, mreq, &resp))) {
-      fprintf(stderr, "Error from tids_handle_request(), rc = %d.\n", rc);
-      return;
+  /* clean up any processes that have completed */
+  tids_sweep_procs(tids);
+  return 0;
+}
+
+/**
+ * Clean up any finished TID request processes
+ *
+ * This is called by the main process after forking each TID request. If you want to be
+ * sure finished processes are cleaned up promptly even during a lull in TID requests,
+ * this can be called from the main thread of the main process. It is not thread-safe,
+ * so should not be used from sub-threads. It should not be called by child processes -
+ * this would probably be harmless but ineffective.
+ *
+ * @param tids
+ */
+void tids_sweep_procs(TIDS_INSTANCE *tids)
+{
+  guint ii;
+  struct tid_process tp = {0};
+  char result[TIDS_MAX_MESSAGE_LEN] = {0};
+  ssize_t result_len;
+  int status;
+  int wait_rc;
+
+  /* loop backwards over the array so we can remove elements as we go */
+  for (ii=tids->pids->len; ii > 0; ii--) {
+    /* ii-1 is the current index - get our own copy, we may destroy the list's copy */
+    tp = g_array_index(tids->pids, struct tid_process, ii-1);
+
+    wait_rc = waitpid(tp.pid, &status, WNOHANG);
+    if (wait_rc == 0)
+      continue; /* process still running */
+
+    if (wait_rc < 0) {
+      /* invalid options will probably keep being invalid, report that condition */
+      if(errno == EINVAL)
+        tr_crit("tids_sweep_procs: waitpid called with invalid options");
+
+      /* If we got ECHILD, that means the PID was invalid; we'll assume the process was
+       * terminated and we missed it. For all other errors, move on
+       * to the next PID to check. */
+      if (errno != ECHILD)
+        continue;
+
+      tr_warning("tid_sweep_procs: TID process %d disappeared", tp.pid);
     }
 
-    if (0 > (rc = tids_send_response(tids, conn, &gssctx, resp))) {
-      fprintf(stderr, "Error from tids_send_response(), rc = %d.\n", rc);
-      return;
+    /* remove the item (we still have a copy of the data) */
+    g_array_remove_index_fast(tids->pids, ii-1); /* disturbs only indices >= ii-1 which we've already handled */
+
+    /* Report exit status unless we got ECHILD above or somehow waitpid returned the wrong pid */
+    if (wait_rc == tp.pid) {
+      if (WIFEXITED(status)) {
+        tr_debug("tids_sweep_procs: TID process %d exited with status %d.", tp.pid, WTERMSIG(status));
+      } else if (WIFSIGNALED(status)) {
+        tr_debug("tids_sweep_procs: TID process %d terminated by signal %d.", tp.pid, WTERMSIG(status));
+      }
+    } else if (wait_rc > 0) {
+      tr_err("tids_sweep_procs: waitpid returned pid %d, expected %d", wait_rc, tp.pid);
     }
-  }  
 
-  return;
-}
+    /* read the pipe - if the TID request worked, it will have written status before terminating */
+    result_len = read(tp.read_fd, result, TIDS_MAX_MESSAGE_LEN);
+    close(tp.read_fd);
 
-TIDS_INSTANCE *tids_create (void)
-{
-  TIDS_INSTANCE *tids = NULL;
-  if (tids = malloc(sizeof(TIDS_INSTANCE)))
-    memset(tids, 0, sizeof(TIDS_INSTANCE));
-  return tids;
+    if ((result_len > 0) && (strcmp(result, TIDS_SUCCESS_MESSAGE) == 0)) {
+      tids->req_count++;
+      tr_info("tids_sweep_procs: TID process %d exited successfully.", tp.pid);
+    } else {
+      tids->error_count++;
+      tr_info("tids_sweep_procs: TID process %d exited with an error.", tp.pid);
+    }
+  }
 }
 
-int tids_start (TIDS_INSTANCE *tids, 
-		TIDS_REQ_FUNC *req_handler,
-		void *cookie)
+/* Process tids requests forever. Should not return except on error. */
+int tids_start (TIDS_INSTANCE *tids,
+                TIDS_REQ_FUNC *req_handler,
+                tids_auth_func *auth_handler,
+                const char *hostname,
+                unsigned int port,
+                void *cookie)
 {
-  int listen = -1;
-  int conn = -1;
-  pid_t pid;
-  int optval = 1;
+  int fd[TR_MAX_SOCKETS]={0};
+  nfds_t n_fd=0;
+  struct pollfd poll_fd[TR_MAX_SOCKETS]={{0}};
+  int ii=0;
 
-  if (0 > (listen = tids_listen(tids, TID_PORT)))
+  n_fd = tids_get_listener(tids, req_handler, auth_handler, hostname, port, cookie, fd, TR_MAX_SOCKETS);
+  if (n_fd <= 0) {
     perror ("Error from tids_listen()");
+    return 1;
+  }
 
-  setsockopt(listen, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
+  tr_info("Trust Path Query Server starting on host %s:%d.", hostname, port);
 
-  /* store the caller's request handler & cookie */
-  tids->req_handler = req_handler;
-  tids->cookie = cookie;
+  /* set up the poll structs */
+  for (ii=0; ii<n_fd; ii++) {
+    poll_fd[ii].fd=fd[ii];
+    poll_fd[ii].events=POLLIN;
+  }
 
   while(1) {	/* accept incoming conns until we are stopped */
+    /* clear out events from previous iteration */
+    for (ii=0; ii<n_fd; ii++)
+      poll_fd[ii].revents=0;
 
-    if (0 > (conn = accept(listen, NULL, NULL))) {
-      perror("Error from TIDS Server accept()");
+    /* wait indefinitely for a connection */
+    if (poll(poll_fd, n_fd, -1) < 0) {
+      perror("Error from poll()");
       return 1;
     }
 
-    if (0 > (pid = fork())) {
-      perror("Error on fork()");
-      return 1;
-    }
+    /* fork handlers for any sockets that have data */
+    for (ii=0; ii<n_fd; ii++) {
+      if (poll_fd[ii].revents == 0)
+        continue;
 
-    if (pid == 0) {
-      close(listen);
-      tids_handle_connection(tids, conn);
-      close(conn);
-      exit(0);
-    } else {
-      close(conn);
+      if ((poll_fd[ii].revents & POLLERR) || (poll_fd[ii].revents & POLLNVAL)) {
+        perror("Error polling fd");
+        continue;
+      }
+
+      if (poll_fd[ii].revents & POLLIN) {
+        if (tids_accept(tids, poll_fd[ii].fd))
+          tr_err("tids_start: error in tids_accept().");
+      }
     }
   }
 
-  return 1;	/* should never get here */
+  return 1;	/* should never get here, loops "forever" */
 }
 
 void tids_destroy (TIDS_INSTANCE *tids)
 {
-  free(tids);
-}
-
+  /* clean up logfiles */
+  tr_log_close();
 
+  if (tids)
+    free(tids);
+}