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);
18 * Returns the next socket to service because it receives a message.
20 * if timeout<0, we ought to implement the adaptative timeout (FIXME)
22 * if timeout=0, do not wait for new message, only handle the ones already there.
24 * if timeout>0 and no message there, wait at most that amount of time before giving up.
26 gras_socket_t gras_trp_select(double timeout) {
27 xbt_dynar_t sockets= ((gras_trp_procdata_t) gras_libdata_by_id(gras_trp_libdata_id))->sockets;
29 double wakeup = gras_os_time() + timeout;
31 /* nextToService used to make sure socket with high number do not starve */
32 /* static int nextToService = 0; */
33 struct timeval tout, *p_tout;
35 int max_fds=0; /* first arg of select: number of existing sockets */
36 /* but accept() of winsock returns sockets bigger than the limit, so don't bother
37 with this tiny optimisation on BillWare */
39 int ready; /* return of select: number of socket ready to be serviced */
40 int fd_setsize; /* FD_SETSIZE not always defined. Get this portably */
42 gras_socket_t sock_iter; /* iterating over all sockets */
43 int cursor; /* iterating over all sockets */
45 /* Check whether there is more data to read from the socket we selected last time.
46 This can happen with tcp buffered sockets since we try to get as much data as we can for them */
47 static gras_socket_t _lastly_selected_socket = NULL;
48 if (_lastly_selected_socket && _lastly_selected_socket->moredata) {
49 VERB0("Returning _lastly_selected_socket since there is more data on it");
50 return _lastly_selected_socket;
53 /* Compute FD_SETSIZE */
55 fd_setsize = sysconf( _SC_OPEN_MAX );
57 # ifdef HAVE_GETDTABLESIZE
58 fd_setsize = getdtablesize();
60 fd_setsize = FD_SETSIZE;
61 # endif /* !USE_SYSCONF */
65 if (timeout > 0) { /* did we timeout already? */
67 DEBUG2("wakeup=%f now=%f",wakeup, now);
68 if (now == -1 || now >= wakeup) {
69 /* didn't find anything; no need to update _lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
70 THROW1(timeout_error,0,
71 "Timeout (%f) elapsed with selecting for incomming connexions",
76 /* construct the set of socket to ear from */
79 xbt_dynar_foreach(sockets,cursor,sock_iter) {
80 if (!sock_iter->valid)
83 if (sock_iter->incoming) {
84 DEBUG1("Considering socket %d for select",sock_iter->sd);
85 #ifndef HAVE_WINSOCK_H
86 if (max_fds < sock_iter->sd)
87 max_fds = sock_iter->sd;
89 FD_SET(sock_iter->sd, &FDS);
91 DEBUG1("Not considering socket %d for select",sock_iter->sd);
97 DEBUG1("No socket to select onto. Sleep %f sec instead.",timeout);
98 gras_os_sleep(timeout);
99 THROW1(timeout_error,0,"No socket to select onto. Sleep %f sec instead",timeout);
101 DEBUG0("No socket to select onto. Return directly.");
102 THROW0(timeout_error,0, "No socket to select onto. Return directly.");
106 #ifndef HAVE_WINSOCK_H
107 /* we cannot have more than FD_SETSIZE sockets
108 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
109 if (++max_fds > fd_setsize && fd_setsize > 0) {
110 WARN1("too many open sockets (%d).",max_fds);
115 max_fds = fd_setsize;
119 /* set the timeout */
120 tout.tv_sec = (unsigned long)(wakeup - now);
121 tout.tv_usec = ((wakeup -now) - ((unsigned long)(wakeup - now))) * 1000000;
123 } else if (timeout == 0) {
128 /* we just do one loop around */
131 /* no timeout: good luck! */
135 DEBUG2("Selecting over %d socket(s); timeout=%f", max_fds-1,timeout);
136 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
137 DEBUG1("select returned %d", ready);
140 case EINTR: /* a signal we don't care about occured. we don't care */
141 /* if we cared, we would have set an handler */
143 case EINVAL: /* invalid value */
144 THROW3(system_error,EINVAL,"invalid select: nb fds: %d, timeout: %d.%d",
145 max_fds, (int)tout.tv_sec,(int) tout.tv_usec);
147 xbt_assert0(0,"Malloc error during the select");
149 THROW2(system_error,errno,"Error during select: %s (%d)",
150 strerror(errno),errno);
153 } else if (ready == 0) {
154 continue; /* this was a timeout */
157 xbt_dynar_foreach(sockets,cursor,sock_iter) {
158 if(!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
162 /* Got a socket to serve */
165 if ( sock_iter->accepting
166 && sock_iter->plugin->socket_accept) {
167 /* not a socket but an ear. accept on it and serve next socket */
168 gras_socket_t accepted=NULL;
170 accepted = (sock_iter->plugin->socket_accept)(sock_iter);
171 DEBUG2("accepted=%p,&accepted=%p",accepted,&accepted);
172 accepted->meas = sock_iter->meas;
174 } else if (sock_iter->recv_ok) {
175 /* Make sure the socket is still alive by reading the first byte */
179 recvd = recv(sock_iter->sd, &lookahead, 1, MSG_PEEK);
181 WARN2("socket %d failed: %s", sock_iter->sd, strerror(errno));
182 /* done with this socket */
183 gras_socket_close(sock_iter);
185 } else if (recvd == 0) {
186 /* Connection reset (=closed) by peer. */
187 DEBUG1("Connection %d reset by peer", sock_iter->sd);
188 sock_iter->valid=0; /* don't close it. User may keep references to it */
190 /* Got a suited socket ! */
192 _lastly_selected_socket = sock_iter;
197 /* This is a file socket. Cannot recv() on it, but it must be alive */
199 _lastly_selected_socket = sock_iter;
204 /* if we're here, the socket we found wasn't really ready to be served */
205 if (ready == 0) /* exausted all sockets given by select. Request new ones */
211 /* No socket found. Maybe we had timeout=0 and nothing to do */
213 THROW0(timeout_error,0,"Timeout");
216 void gras_trp_sg_setup(gras_trp_plugin_t plug) {
217 THROW0(mismatch_error,0,"No SG transport on live platforms");