1 /* rl_transport - RL specific functions for transport */
3 /* Copyright (c) 2004, 2005, 2006, 2007, 2009, 2010. The SimGrid Team.
4 * All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include "gras/Transport/transport_private.h"
12 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(gras_trp);
14 /* check transport_private.h for an explanation of this variable */
15 gras_socket_t _gras_lastly_selected_socket = NULL;
20 * Returns the next socket to service because it receives a message.
22 * if timeout<0, we ought to implement the adaptative timeout (FIXME)
25 * if timeout>0 and no message there, wait at most that amount of time before giving up.
27 gras_socket_t gras_trp_select(double timeout)
30 ((gras_trp_procdata_t)
31 gras_libdata_by_id(gras_trp_libdata_id))->sockets;
33 double wakeup = gras_os_time() + timeout;
35 /* nextToService used to make sure socket with high number do not starve */
36 /* static int nextToService = 0; */
37 struct timeval tout, *p_tout;
39 int max_fds = 0; /* first arg of select: number of existing sockets */
40 /* but accept() of winsock returns sockets bigger than the limit, so don't bother
41 with this tiny optimisation on BillWare */
43 int ready; /* return of select: number of socket ready to be serviced */
44 static int fd_setsize = -1; /* FD_SETSIZE not always defined. Get this portably */
46 gras_socket_t sock_iter; /* iterating over all sockets */
47 unsigned int cursor; /* iterating over all sockets */
49 /* Check whether there is more data to read from the socket we selected last time.
50 This can happen with tcp buffered sockets since we try to get as much data as we can for them */
51 if (_gras_lastly_selected_socket
52 && _gras_lastly_selected_socket->moredata) {
54 ("Returning _gras_lastly_selected_socket since there is more data on it");
55 return _gras_lastly_selected_socket;
58 /* Compute FD_SETSIZE on need */
61 fd_setsize = sysconf(_SC_OPEN_MAX);
63 # ifdef HAVE_GETDTABLESIZE
64 fd_setsize = getdtablesize();
66 fd_setsize = FD_SETSIZE;
67 # endif /* !USE_SYSCONF */
72 if (timeout > 0) { /* did we timeout already? */
74 XBT_DEBUG("wakeup=%f now=%f", wakeup, now);
75 if (now == -1 || now >= wakeup) {
76 /* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
77 THROWF(timeout_error, 0,
78 "Timeout (%f) elapsed with selecting for incomming connexions",
83 /* construct the set of socket to ear from */
86 xbt_dynar_foreach(sockets, cursor, sock_iter) {
87 if (!sock_iter->valid)
90 if (sock_iter->incoming) {
91 XBT_DEBUG("Considering socket %d for select", sock_iter->sd);
92 #ifndef HAVE_WINSOCK_H
93 if (max_fds < sock_iter->sd)
94 max_fds = sock_iter->sd;
99 FD_SET(sock_iter->sd, &FDS);
101 XBT_DEBUG("Not considering socket %d for select", sock_iter->sd);
108 XBT_DEBUG("No socket to select onto. Sleep %f sec instead.", timeout);
109 gras_os_sleep(timeout);
110 THROWF(timeout_error, 0,
111 "No socket to select onto. Sleep %f sec instead", timeout);
113 XBT_DEBUG("No socket to select onto. Return directly.");
114 THROWF(timeout_error, 0,
115 "No socket to select onto. Return directly.");
118 #ifndef HAVE_WINSOCK_H
119 /* we cannot have more than FD_SETSIZE sockets
120 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
121 if (++max_fds > fd_setsize && fd_setsize > 0) {
122 XBT_WARN("too many open sockets (%d).", max_fds);
127 max_fds = fd_setsize;
130 tout.tv_sec = tout.tv_usec = 0;
132 /* set the timeout */
133 tout.tv_sec = (unsigned long) (wakeup - now);
135 ((wakeup - now) - ((unsigned long) (wakeup - now))) * 1000000;
137 } else if (timeout == 0) {
142 /* we just do one loop around */
145 /* no timeout: good luck! */
149 XBT_DEBUG("Selecting over %d socket(s); timeout=%f", max_fds - 1,
151 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
152 XBT_DEBUG("select returned %d", ready);
155 case EINTR: /* a signal we don't care about occured. we don't care */
156 /* if we cared, we would have set an handler */
158 case EINVAL: /* invalid value */
159 THROWF(system_error, EINVAL,
160 "invalid select: nb fds: %d, timeout: %d.%d", max_fds,
161 (int) tout.tv_sec, (int) tout.tv_usec);
163 xbt_die("Malloc error during the select");
165 THROWF(system_error, errno, "Error during select: %s (%d)",
166 strerror(errno), errno);
169 } else if (ready == 0) {
170 continue; /* this was a timeout */
173 xbt_dynar_foreach(sockets, cursor, sock_iter) {
174 if (!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
178 /* Got a socket to serve */
181 if (sock_iter->accepting && sock_iter->plugin->socket_accept) {
182 /* not a socket but an ear. accept on it and serve next socket */
183 gras_socket_t accepted = NULL;
185 /* release mutex before accept; it will change the sockets dynar, so we have to break the foreach asap */
186 xbt_dynar_cursor_unlock(sockets);
187 accepted = (sock_iter->plugin->socket_accept) (sock_iter);
189 XBT_DEBUG("accepted=%p,&accepted=%p", accepted, &accepted);
190 accepted->meas = sock_iter->meas;
194 /* Make sure the socket is still alive by reading the first byte */
197 if (sock_iter->recvd) {
198 /* Socket wasn't used since last time! Don't bother checking whether it's still alive */
201 recvd = read(sock_iter->sd, &sock_iter->recvd_val, 1);
205 XBT_WARN("socket %d failed: %s", sock_iter->sd, strerror(errno));
206 /* done with this socket; remove it and break the foreach since it will change the dynar */
207 xbt_dynar_cursor_unlock(sockets);
208 gras_socket_close(sock_iter);
210 } else if (recvd == 0) {
211 /* Connection reset (=closed) by peer. */
212 XBT_DEBUG("Connection %d reset by peer", sock_iter->sd);
213 sock_iter->valid = 0; /* don't close it. User may keep references to it */
215 /* Got a suited socket ! */
217 sock_iter->recvd = 1;
218 XBT_DEBUG("Filled little buffer (%c %x %d)", sock_iter->recvd_val,
219 sock_iter->recvd_val, recvd);
220 _gras_lastly_selected_socket = sock_iter;
221 /* break sync dynar iteration */
222 xbt_dynar_cursor_unlock(sockets);
227 /* if we're here, the socket we found wasn't really ready to be served */
228 if (ready == 0) { /* exausted all sockets given by select. Request new ones */
230 xbt_dynar_cursor_unlock(sockets);
237 /* No socket found. Maybe we had timeout=0 and nothing to do */
238 XBT_DEBUG("TIMEOUT");
239 THROWF(timeout_error, 0, "Timeout");
242 void gras_trp_sg_setup(gras_trp_plugin_t plug)
244 THROWF(mismatch_error, 0, "No SG transport on live platforms");