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;
93 FD_SET(sock_iter->sd, &FDS);
95 DEBUG1("Not considering socket %d for select",sock_iter->sd);
101 DEBUG1("No socket to select onto. Sleep %f sec instead.",timeout);
102 gras_os_sleep(timeout);
103 THROW1(timeout_error,0,"No socket to select onto. Sleep %f sec instead",timeout);
105 DEBUG0("No socket to select onto. Return directly.");
106 THROW0(timeout_error,0, "No socket to select onto. Return directly.");
110 #ifndef HAVE_WINSOCK_H
111 /* we cannot have more than FD_SETSIZE sockets
112 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
113 if (++max_fds > fd_setsize && fd_setsize > 0) {
114 WARN1("too many open sockets (%d).",max_fds);
119 max_fds = fd_setsize;
123 /* set the timeout */
124 tout.tv_sec = (unsigned long)(wakeup - now);
125 tout.tv_usec = ((wakeup -now) - ((unsigned long)(wakeup - now))) * 1000000;
127 } else if (timeout == 0) {
132 /* we just do one loop around */
135 /* no timeout: good luck! */
139 DEBUG2("Selecting over %d socket(s); timeout=%f", max_fds-1,timeout);
140 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
141 DEBUG1("select returned %d", ready);
144 case EINTR: /* a signal we don't care about occured. we don't care */
145 /* if we cared, we would have set an handler */
147 case EINVAL: /* invalid value */
148 THROW3(system_error,EINVAL,"invalid select: nb fds: %d, timeout: %d.%d",
149 max_fds, (int)tout.tv_sec,(int) tout.tv_usec);
151 xbt_assert0(0,"Malloc error during the select");
153 THROW2(system_error,errno,"Error during select: %s (%d)",
154 strerror(errno),errno);
157 } else if (ready == 0) {
158 continue; /* this was a timeout */
161 xbt_dynar_foreach(sockets,cursor,sock_iter) {
162 if(!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
166 /* Got a socket to serve */
169 if ( sock_iter->accepting
170 && sock_iter->plugin->socket_accept) {
171 /* not a socket but an ear. accept on it and serve next socket */
172 gras_socket_t accepted=NULL;
174 accepted = (sock_iter->plugin->socket_accept)(sock_iter);
175 DEBUG2("accepted=%p,&accepted=%p",accepted,&accepted);
176 accepted->meas = sock_iter->meas;
178 } else if (sock_iter->recv_ok) {
179 /* Make sure the socket is still alive by reading the first byte */
183 recvd = recv(sock_iter->sd, &lookahead, 1, MSG_PEEK);
185 WARN2("socket %d failed: %s", sock_iter->sd, strerror(errno));
186 /* done with this socket */
187 gras_socket_close(sock_iter);
189 } else if (recvd == 0) {
190 /* Connection reset (=closed) by peer. */
191 DEBUG1("Connection %d reset by peer", sock_iter->sd);
192 sock_iter->valid=0; /* don't close it. User may keep references to it */
194 /* Got a suited socket ! */
196 _gras_lastly_selected_socket = sock_iter;
201 /* This is a file socket. Cannot recv() on it, but it must be alive */
203 _gras_lastly_selected_socket = sock_iter;
208 /* if we're here, the socket we found wasn't really ready to be served */
209 if (ready == 0) /* exausted all sockets given by select. Request new ones */
215 /* No socket found. Maybe we had timeout=0 and nothing to do */
217 THROW0(timeout_error,0,"Timeout");
220 void gras_trp_sg_setup(gras_trp_plugin_t plug) {
221 THROW0(mismatch_error,0,"No SG transport on live platforms");