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 int fd_setsize; /* 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 */
57 fd_setsize = sysconf( _SC_OPEN_MAX );
59 # ifdef HAVE_GETDTABLESIZE
60 fd_setsize = getdtablesize();
62 fd_setsize = FD_SETSIZE;
63 # endif /* !USE_SYSCONF */
67 if (timeout > 0) { /* did we timeout already? */
69 DEBUG2("wakeup=%f now=%f",wakeup, now);
70 if (now == -1 || now >= wakeup) {
71 /* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
72 THROW1(timeout_error,0,
73 "Timeout (%f) elapsed with selecting for incomming connexions",
78 /* construct the set of socket to ear from */
81 xbt_dynar_foreach(sockets,cursor,sock_iter) {
82 if (!sock_iter->valid)
85 if (sock_iter->incoming) {
86 DEBUG1("Considering socket %d for select",sock_iter->sd);
87 #ifndef HAVE_WINSOCK_H
88 if (max_fds < sock_iter->sd)
89 max_fds = sock_iter->sd;
91 FD_SET(sock_iter->sd, &FDS);
93 DEBUG1("Not considering socket %d for select",sock_iter->sd);
99 DEBUG1("No socket to select onto. Sleep %f sec instead.",timeout);
100 gras_os_sleep(timeout);
101 THROW1(timeout_error,0,"No socket to select onto. Sleep %f sec instead",timeout);
103 DEBUG0("No socket to select onto. Return directly.");
104 THROW0(timeout_error,0, "No socket to select onto. Return directly.");
108 #ifndef HAVE_WINSOCK_H
109 /* we cannot have more than FD_SETSIZE sockets
110 ... but with WINSOCK which returns sockets higher than the limit (killing this optim) */
111 if (++max_fds > fd_setsize && fd_setsize > 0) {
112 WARN1("too many open sockets (%d).",max_fds);
117 max_fds = fd_setsize;
121 /* set the timeout */
122 tout.tv_sec = (unsigned long)(wakeup - now);
123 tout.tv_usec = ((wakeup -now) - ((unsigned long)(wakeup - now))) * 1000000;
125 } else if (timeout == 0) {
130 /* we just do one loop around */
133 /* no timeout: good luck! */
137 DEBUG2("Selecting over %d socket(s); timeout=%f", max_fds-1,timeout);
138 ready = select(max_fds, &FDS, NULL, NULL, p_tout);
139 DEBUG1("select returned %d", ready);
142 case EINTR: /* a signal we don't care about occured. we don't care */
143 /* if we cared, we would have set an handler */
145 case EINVAL: /* invalid value */
146 THROW3(system_error,EINVAL,"invalid select: nb fds: %d, timeout: %d.%d",
147 max_fds, (int)tout.tv_sec,(int) tout.tv_usec);
149 xbt_assert0(0,"Malloc error during the select");
151 THROW2(system_error,errno,"Error during select: %s (%d)",
152 strerror(errno),errno);
155 } else if (ready == 0) {
156 continue; /* this was a timeout */
159 xbt_dynar_foreach(sockets,cursor,sock_iter) {
160 if(!FD_ISSET(sock_iter->sd, &FDS)) { /* this socket is not ready */
164 /* Got a socket to serve */
167 if ( sock_iter->accepting
168 && sock_iter->plugin->socket_accept) {
169 /* not a socket but an ear. accept on it and serve next socket */
170 gras_socket_t accepted=NULL;
172 accepted = (sock_iter->plugin->socket_accept)(sock_iter);
173 DEBUG2("accepted=%p,&accepted=%p",accepted,&accepted);
174 accepted->meas = sock_iter->meas;
176 } else if (sock_iter->recv_ok) {
177 /* Make sure the socket is still alive by reading the first byte */
181 recvd = recv(sock_iter->sd, &lookahead, 1, MSG_PEEK);
183 WARN2("socket %d failed: %s", sock_iter->sd, strerror(errno));
184 /* done with this socket */
185 gras_socket_close(sock_iter);
187 } else if (recvd == 0) {
188 /* Connection reset (=closed) by peer. */
189 DEBUG1("Connection %d reset by peer", sock_iter->sd);
190 sock_iter->valid=0; /* don't close it. User may keep references to it */
192 /* Got a suited socket ! */
194 _gras_lastly_selected_socket = sock_iter;
199 /* This is a file socket. Cannot recv() on it, but it must be alive */
201 _gras_lastly_selected_socket = sock_iter;
206 /* if we're here, the socket we found wasn't really ready to be served */
207 if (ready == 0) /* exausted all sockets given by select. Request new ones */
213 /* No socket found. Maybe we had timeout=0 and nothing to do */
215 THROW0(timeout_error,0,"Timeout");
218 void gras_trp_sg_setup(gras_trp_plugin_t plug) {
219 THROW0(mismatch_error,0,"No SG transport on live platforms");