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) gras_libdata_by_id(gras_trp_libdata_id))->sockets;
32 double wakeup = gras_os_time() + timeout;
34 /* nextToService used to make sure socket with high number do not starve */
35 /* static int nextToService = 0; */
36 struct timeval tout, *p_tout;
38 int max_fds = 0; /* first arg of select: number of existing sockets */
39 /* but accept() of winsock returns sockets bigger than the limit, so don't bother
40 with this tiny optimisation on BillWare */
42 int ready; /* return of select: number of socket ready to be serviced */
43 static int fd_setsize = -1; /* FD_SETSIZE not always defined. Get this portably */
45 gras_socket_t sock_iter; /* iterating over all sockets */
46 unsigned int cursor; /* iterating over all sockets */
48 /* Check whether there is more data to read from the socket we selected last time.
49 This can happen with tcp buffered sockets since we try to get as much data as we can for them */
50 if (_gras_lastly_selected_socket && _gras_lastly_selected_socket->moredata) {
52 ("Returning _gras_lastly_selected_socket since there is more data on it");
53 return _gras_lastly_selected_socket;
56 /* Compute FD_SETSIZE on need */
59 fd_setsize = sysconf(_SC_OPEN_MAX);
61 # ifdef HAVE_GETDTABLESIZE
62 fd_setsize = getdtablesize();
64 fd_setsize = FD_SETSIZE;
65 # endif /* !USE_SYSCONF */
70 if (timeout > 0) { /* did we timeout already? */
72 DEBUG2("wakeup=%f now=%f", wakeup, now);
73 if (now == -1 || now >= wakeup) {
74 /* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
75 THROW1(timeout_error, 0,
76 "Timeout (%f) elapsed with selecting for incomming connexions",
81 /* construct the set of socket to ear from */
84 xbt_dynar_foreach(sockets, cursor, sock_iter) {
85 if (!sock_iter->valid)
88 if (sock_iter->incoming) {
89 DEBUG1("Considering socket %d for select", sock_iter->sd);
90 #ifndef HAVE_WINSOCK_H
91 if (max_fds < sock_iter->sd)
92 max_fds = sock_iter->sd;
97 FD_SET(sock_iter->sd, &FDS);
99 DEBUG1("Not considering socket %d for select", sock_iter->sd);
106 DEBUG1("No socket to select onto. Sleep %f sec instead.", timeout);
107 gras_os_sleep(timeout);
108 THROW1(timeout_error, 0,
109 "No socket to select onto. Sleep %f sec instead", timeout);
111 DEBUG0("No socket to select onto. Return directly.");
112 THROW0(timeout_error, 0,
113 "No socket to select onto. Return directly.");
116 #ifndef HAVE_WINSOCK_H
117 /* we cannot have more than FD_SETSIZE sockets
118 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
119 if (++max_fds > fd_setsize && fd_setsize > 0) {
120 WARN1("too many open sockets (%d).", max_fds);
125 max_fds = fd_setsize;
128 tout.tv_sec = tout.tv_usec = 0;
130 /* set the timeout */
131 tout.tv_sec = (unsigned long) (wakeup - now);
133 ((wakeup - now) - ((unsigned long) (wakeup - now))) * 1000000;
135 } else if (timeout == 0) {
140 /* we just do one loop around */
143 /* no timeout: good luck! */
147 DEBUG2("Selecting over %d socket(s); timeout=%f", max_fds - 1, timeout);
148 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
149 DEBUG1("select returned %d", ready);
152 case EINTR: /* a signal we don't care about occured. we don't care */
153 /* if we cared, we would have set an handler */
155 case EINVAL: /* invalid value */
156 THROW3(system_error, EINVAL,
157 "invalid select: nb fds: %d, timeout: %d.%d", max_fds,
158 (int) tout.tv_sec, (int) tout.tv_usec);
160 xbt_die("Malloc error during the select");
162 THROW2(system_error, errno, "Error during select: %s (%d)",
163 strerror(errno), errno);
166 } else if (ready == 0) {
167 continue; /* this was a timeout */
170 xbt_dynar_foreach(sockets, cursor, sock_iter) {
171 if (!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
175 /* Got a socket to serve */
178 if (sock_iter->accepting && sock_iter->plugin->socket_accept) {
179 /* not a socket but an ear. accept on it and serve next socket */
180 gras_socket_t accepted = NULL;
182 /* release mutex before accept; it will change the sockets dynar, so we have to break the foreach asap */
183 xbt_dynar_cursor_unlock(sockets);
184 accepted = (sock_iter->plugin->socket_accept) (sock_iter);
186 DEBUG2("accepted=%p,&accepted=%p", accepted, &accepted);
187 accepted->meas = sock_iter->meas;
191 /* Make sure the socket is still alive by reading the first byte */
194 if (sock_iter->recvd) {
195 /* Socket wasn't used since last time! Don't bother checking whether it's still alive */
198 recvd = read(sock_iter->sd, &sock_iter->recvd_val, 1);
202 WARN2("socket %d failed: %s", sock_iter->sd, strerror(errno));
203 /* done with this socket; remove it and break the foreach since it will change the dynar */
204 xbt_dynar_cursor_unlock(sockets);
205 gras_socket_close(sock_iter);
207 } else if (recvd == 0) {
208 /* Connection reset (=closed) by peer. */
209 DEBUG1("Connection %d reset by peer", sock_iter->sd);
210 sock_iter->valid = 0; /* don't close it. User may keep references to it */
212 /* Got a suited socket ! */
214 sock_iter->recvd = 1;
215 DEBUG3("Filled little buffer (%c %x %d)", sock_iter->recvd_val,
216 sock_iter->recvd_val, recvd);
217 _gras_lastly_selected_socket = sock_iter;
218 /* break sync dynar iteration */
219 xbt_dynar_cursor_unlock(sockets);
224 /* if we're here, the socket we found wasn't really ready to be served */
225 if (ready == 0) { /* exausted all sockets given by select. Request new ones */
227 xbt_dynar_cursor_unlock(sockets);
234 /* No socket found. Maybe we had timeout=0 and nothing to do */
236 THROW0(timeout_error, 0, "Timeout");
239 void gras_trp_sg_setup(gras_trp_plugin_t plug)
241 THROW0(mismatch_error, 0, "No SG transport on live platforms");