3 /* rl_transport - RL specific functions for transport */
5 /* Copyright (c) 2004 Martin Quinson. All rights reserved. */
7 /* This program is free software; you can redistribute it and/or modify it
8 * under the terms of the license (GNU LGPL) which comes with this package. */
12 #include "gras/Transport/transport_private.h"
13 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(gras_trp);
15 /* check transport_private.h for an explanation of this variable */
16 gras_socket_t _gras_lastly_selected_socket = NULL;
21 * Returns the next socket to service because it receives a message.
23 * if timeout<0, we ought to implement the adaptative timeout (FIXME)
25 * if timeout=0, do not wait for new message, only handle the ones already there.
27 * if timeout>0 and no message there, wait at most that amount of time before giving up.
29 gras_socket_t gras_trp_select(double timeout) {
30 xbt_dynar_t sockets= ((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 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) {
51 VERB0("Returning _gras_lastly_selected_socket since there is more data on it");
52 return _gras_lastly_selected_socket;
55 /* Compute FD_SETSIZE on need */
58 fd_setsize = sysconf( _SC_OPEN_MAX );
60 # ifdef HAVE_GETDTABLESIZE
61 fd_setsize = getdtablesize();
63 fd_setsize = FD_SETSIZE;
64 # endif /* !USE_SYSCONF */
69 if (timeout > 0) { /* did we timeout already? */
71 DEBUG2("wakeup=%f now=%f",wakeup, now);
72 if (now == -1 || now >= wakeup) {
73 /* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
74 THROW1(timeout_error,0,
75 "Timeout (%f) elapsed with selecting for incomming connexions",
80 /* construct the set of socket to ear from */
83 xbt_dynar_foreach(sockets,cursor,sock_iter) {
84 if (!sock_iter->valid)
87 if (sock_iter->incoming) {
88 DEBUG1("Considering socket %d for select",sock_iter->sd);
89 #ifndef HAVE_WINSOCK_H
90 if (max_fds < sock_iter->sd)
91 max_fds = sock_iter->sd;
96 FD_SET(sock_iter->sd, &FDS);
98 DEBUG1("Not considering socket %d for select",sock_iter->sd);
105 DEBUG1("No socket to select onto. Sleep %f sec instead.",timeout);
106 gras_os_sleep(timeout);
107 THROW1(timeout_error,0,"No socket to select onto. Sleep %f sec instead",timeout);
109 DEBUG0("No socket to select onto. Return directly.");
110 THROW0(timeout_error,0, "No socket to select onto. Return directly.");
114 #ifndef HAVE_WINSOCK_H
115 /* we cannot have more than FD_SETSIZE sockets
116 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
117 if (++max_fds > fd_setsize && fd_setsize > 0) {
118 WARN1("too many open sockets (%d).",max_fds);
123 max_fds = fd_setsize;
127 /* set the timeout */
128 tout.tv_sec = (unsigned long)(wakeup - now);
129 tout.tv_usec = ((wakeup -now) - ((unsigned long)(wakeup - now))) * 1000000;
131 } else if (timeout == 0) {
136 /* we just do one loop around */
139 /* no timeout: good luck! */
143 DEBUG2("Selecting over %d socket(s); timeout=%f", max_fds-1,timeout);
144 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
145 DEBUG1("select returned %d", ready);
148 case EINTR: /* a signal we don't care about occured. we don't care */
149 /* if we cared, we would have set an handler */
151 case EINVAL: /* invalid value */
152 THROW3(system_error,EINVAL,"invalid select: nb fds: %d, timeout: %d.%d",
153 max_fds, (int)tout.tv_sec,(int) tout.tv_usec);
155 xbt_assert0(0,"Malloc error during the select");
157 THROW2(system_error,errno,"Error during select: %s (%d)",
158 strerror(errno),errno);
161 } else if (ready == 0) {
162 continue; /* this was a timeout */
165 xbt_dynar_foreach(sockets,cursor,sock_iter) {
166 if(!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
170 /* Got a socket to serve */
173 if ( sock_iter->accepting
174 && sock_iter->plugin->socket_accept) {
175 /* not a socket but an ear. accept on it and serve next socket */
176 gras_socket_t accepted=NULL;
178 /* release mutex before accept; it will change the sockets dynar, so we have to break the foreach asap */
179 xbt_dynar_cursor_unlock(sockets);
180 accepted = (sock_iter->plugin->socket_accept)(sock_iter);
182 DEBUG2("accepted=%p,&accepted=%p",accepted,&accepted);
183 accepted->meas = sock_iter->meas;
186 } else if (sock_iter->recv_ok) {
187 /* Make sure the socket is still alive by reading the first byte */
191 recvd = recv(sock_iter->sd, &lookahead, 1, MSG_PEEK);
193 WARN2("socket %d failed: %s", sock_iter->sd, strerror(errno));
194 /* done with this socket; remove it and break the foreach since it will change the dynar */
195 xbt_dynar_cursor_unlock(sockets);
196 gras_socket_close(sock_iter);
198 } else if (recvd == 0) {
199 /* Connection reset (=closed) by peer. */
200 DEBUG1("Connection %d reset by peer", sock_iter->sd);
201 sock_iter->valid=0; /* don't close it. User may keep references to it */
203 /* Got a suited socket ! */
205 _gras_lastly_selected_socket = sock_iter;
206 /* break sync dynar iteration */
207 xbt_dynar_cursor_unlock(sockets);
212 /* This is a file socket. Cannot recv() on it, but it must be alive */
214 _gras_lastly_selected_socket = sock_iter;
215 xbt_dynar_cursor_unlock(sockets);
219 /* if we're here, the socket we found wasn't really ready to be served */
220 if (ready == 0) { /* exausted all sockets given by select. Request new ones */
222 xbt_dynar_cursor_unlock(sockets);
229 /* No socket found. Maybe we had timeout=0 and nothing to do */
231 THROW0(timeout_error,0,"Timeout");
234 void gras_trp_sg_setup(gras_trp_plugin_t plug) {
235 THROW0(mismatch_error,0,"No SG transport on live platforms");