378 lines
9.3 KiB
C
378 lines
9.3 KiB
C
/* Serial port emulation using sockets.
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Copyright (C) 1998-2022 Free Software Foundation, Inc.
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Contributed by Cygnus Solutions.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* FIXME: will obviously need to evolve.
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- connectionless sockets might be more appropriate. */
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/* This must come before any other includes. */
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#include "defs.h"
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#include <errno.h>
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#include <netdb.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <sys/select.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include "sim-main.h"
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#include "sim-assert.h"
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#include "sim-options.h"
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#include "dv-sockser.h"
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#ifndef HAVE_SOCKLEN_T
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typedef int socklen_t;
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#endif
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/* Compromise between eating cpu and properly busy-waiting.
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One could have an option to set this but for now that seems
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like featuritis. */
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#define DEFAULT_TIMEOUT 1000 /* microseconds */
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/* FIXME: These should allocated at run time and kept with other simulator
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state (duh...). Later. */
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const char * sockser_addr = NULL;
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/* Timeout in microseconds during status flag computation.
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Setting this to zero achieves proper busy wait semantics but eats cpu. */
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static unsigned int sockser_timeout = DEFAULT_TIMEOUT;
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static int sockser_listen_fd = -1;
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static int sockser_fd = -1;
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/* FIXME: use tree properties when they're ready. */
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typedef enum {
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OPTION_ADDR = OPTION_START
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} SOCKSER_OPTIONS;
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static DECLARE_OPTION_HANDLER (sockser_option_handler);
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static const OPTION sockser_options[] =
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{
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{ { "sockser-addr", required_argument, NULL, OPTION_ADDR },
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'\0', "SOCKET ADDRESS", "Set serial emulation socket address",
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sockser_option_handler, NULL },
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{ { NULL, no_argument, NULL, 0 }, '\0', NULL, NULL, NULL, NULL }
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};
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static SIM_RC
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sockser_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
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char *arg, int is_command)
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{
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switch (opt)
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{
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case OPTION_ADDR :
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sockser_addr = arg;
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break;
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}
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return SIM_RC_OK;
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}
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static SIM_RC
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dv_sockser_init (SIM_DESC sd)
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{
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struct hostent *hostent;
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struct sockaddr_in sockaddr;
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char hostname[100];
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const char *port_str;
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int tmp,port;
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if (STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT
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|| sockser_addr == NULL)
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return SIM_RC_OK;
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if (*sockser_addr == '/')
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{
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/* support for these can come later */
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sim_io_eprintf (sd, "sockser init: unix domain sockets not supported: `%s'\n",
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sockser_addr);
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return SIM_RC_FAIL;
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}
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port_str = strchr (sockser_addr, ':');
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if (!port_str)
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{
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sim_io_eprintf (sd, "sockser init: missing port number: `%s'\n",
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sockser_addr);
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return SIM_RC_FAIL;
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}
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tmp = port_str - sockser_addr;
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if (tmp >= sizeof hostname)
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tmp = sizeof (hostname) - 1;
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strncpy (hostname, sockser_addr, tmp);
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hostname[tmp] = '\000';
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port = atoi (port_str + 1);
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hostent = gethostbyname (hostname);
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if (! hostent)
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{
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sim_io_eprintf (sd, "sockser init: unknown host: %s\n",
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hostname);
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return SIM_RC_FAIL;
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}
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sockser_listen_fd = socket (PF_INET, SOCK_STREAM, 0);
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if (sockser_listen_fd == -1)
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{
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sim_io_eprintf (sd, "sockser init: unable to get socket: %s\n",
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strerror (errno));
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return SIM_RC_FAIL;
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}
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sockaddr.sin_family = PF_INET;
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sockaddr.sin_port = htons (port);
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memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
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sizeof (struct in_addr));
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tmp = 1;
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if (setsockopt (sockser_listen_fd, SOL_SOCKET, SO_REUSEADDR, (void*)& tmp, sizeof (tmp)) < 0)
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{
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sim_io_eprintf (sd, "sockser init: unable to set SO_REUSEADDR: %s\n",
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strerror (errno));
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}
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if (bind (sockser_listen_fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr)) < 0)
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{
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sim_io_eprintf (sd, "sockser init: unable to bind socket address: %s\n",
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strerror (errno));
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close (sockser_listen_fd);
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sockser_listen_fd = -1;
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return SIM_RC_FAIL;
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}
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if (listen (sockser_listen_fd, 1) < 0)
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{
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sim_io_eprintf (sd, "sockser init: unable to set up listener: %s\n",
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strerror (errno));
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close (sockser_listen_fd);
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sockser_listen_fd = -1;
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return SIM_RC_OK;
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}
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/* Handle writes to missing client -> SIGPIPE.
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??? Need a central signal management module. */
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#ifdef SIGPIPE
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{
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RETSIGTYPE (*orig) ();
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orig = signal (SIGPIPE, SIG_IGN);
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/* If a handler is already set up, don't mess with it. */
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if (orig != SIG_DFL && orig != SIG_IGN)
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signal (SIGPIPE, orig);
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}
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#endif
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return SIM_RC_OK;
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}
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static void
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dv_sockser_uninstall (SIM_DESC sd)
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{
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if (sockser_listen_fd != -1)
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{
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close (sockser_listen_fd);
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sockser_listen_fd = -1;
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}
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if (sockser_fd != -1)
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{
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close (sockser_fd);
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sockser_fd = -1;
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}
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}
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/* Provide a prototype to silence -Wmissing-prototypes. */
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extern MODULE_INIT_FN sim_install_dv_sockser;
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SIM_RC
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sim_install_dv_sockser (SIM_DESC sd)
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{
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SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
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if (sim_add_option_table (sd, NULL, sockser_options) != SIM_RC_OK)
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return SIM_RC_FAIL;
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sim_module_add_init_fn (sd, dv_sockser_init);
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sim_module_add_uninstall_fn (sd, dv_sockser_uninstall);
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return SIM_RC_OK;
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}
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static int
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connected_p (SIM_DESC sd)
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{
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int numfds,flags;
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struct timeval tv;
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fd_set readfds;
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struct sockaddr sockaddr;
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socklen_t addrlen;
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if (sockser_listen_fd == -1)
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return 0;
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if (sockser_fd >= 0)
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{
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/* FIXME: has client gone away? */
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return 1;
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}
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/* Not connected. Connect with a client if there is one. */
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FD_ZERO (&readfds);
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FD_SET (sockser_listen_fd, &readfds);
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/* ??? One can certainly argue this should be done differently,
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but for now this is sufficient. */
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tv.tv_sec = 0;
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tv.tv_usec = sockser_timeout;
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numfds = select (sockser_listen_fd + 1, &readfds, 0, 0, &tv);
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if (numfds <= 0)
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return 0;
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addrlen = sizeof (sockaddr);
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sockser_fd = accept (sockser_listen_fd, &sockaddr, &addrlen);
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if (sockser_fd == -1)
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return 0;
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/* Set non-blocking i/o. */
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#if defined(F_GETFL) && defined(O_NONBLOCK)
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flags = fcntl (sockser_fd, F_GETFL);
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flags |= O_NONBLOCK;
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if (fcntl (sockser_fd, F_SETFL, flags) == -1)
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{
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sim_io_eprintf (sd, "unable to set nonblocking i/o");
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close (sockser_fd);
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sockser_fd = -1;
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return 0;
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}
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#endif
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return 1;
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}
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int
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dv_sockser_status (SIM_DESC sd)
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{
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int numrfds,numwfds,status;
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struct timeval tv;
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fd_set readfds,writefds;
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/* status to return if the socket isn't set up, or select fails */
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status = DV_SOCKSER_INPUT_EMPTY | DV_SOCKSER_OUTPUT_EMPTY |
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DV_SOCKSER_DISCONNECTED;
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if (! connected_p (sd))
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return status;
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FD_ZERO (&readfds);
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FD_ZERO (&writefds);
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FD_SET (sockser_fd, &readfds);
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FD_SET (sockser_fd, &writefds);
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/* ??? One can certainly argue this should be done differently,
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but for now this is sufficient. The read is done separately
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from the write to enforce the delay which we heuristically set to
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once every SOCKSER_TIMEOUT_FREQ tries.
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No, this isn't great for SMP situations, blah blah blah. */
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{
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static int n;
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#define SOCKSER_TIMEOUT_FREQ 42
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if (++n == SOCKSER_TIMEOUT_FREQ)
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n = 0;
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if (n == 0)
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{
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tv.tv_sec = 0;
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tv.tv_usec = sockser_timeout;
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numrfds = select (sockser_fd + 1, &readfds, 0, 0, &tv);
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tv.tv_sec = 0;
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tv.tv_usec = 0;
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numwfds = select (sockser_fd + 1, 0, &writefds, 0, &tv);
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}
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else /* do both selects at once */
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{
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tv.tv_sec = 0;
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tv.tv_usec = 0;
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numrfds = numwfds = select (sockser_fd + 1, &readfds, &writefds, 0, &tv);
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}
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}
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status = 0;
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if (numrfds <= 0 || ! FD_ISSET (sockser_fd, &readfds))
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status |= DV_SOCKSER_INPUT_EMPTY;
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if (numwfds <= 0 || FD_ISSET (sockser_fd, &writefds))
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status |= DV_SOCKSER_OUTPUT_EMPTY;
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return status;
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}
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int
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dv_sockser_write_buffer (SIM_DESC sd, const unsigned char *buffer,
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unsigned nr_bytes)
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{
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int n;
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if (! connected_p (sd))
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return -1;
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n = write (sockser_fd, buffer, nr_bytes);
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if (n == -1)
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{
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if (errno == EPIPE)
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{
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close (sockser_fd);
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sockser_fd = -1;
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}
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return -1;
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}
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if (n != nr_bytes)
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return -1;
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return nr_bytes;
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}
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int
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dv_sockser_write (SIM_DESC sd, unsigned char c)
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{
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return dv_sockser_write_buffer (sd, &c, 1);
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}
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int
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dv_sockser_read (SIM_DESC sd)
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{
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unsigned char c;
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int n;
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if (! connected_p (sd))
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return -1;
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n = read (sockser_fd, &c, 1);
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/* ??? We're assuming semantics that may not be correct for all hosts.
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In particular (from cvssrc/src/server.c), this assumes that we are using
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BSD or POSIX nonblocking I/O. System V nonblocking I/O returns zero if
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there is nothing to read. */
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if (n == 0)
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{
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close (sockser_fd);
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sockser_fd = -1;
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return -1;
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}
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if (n != 1)
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return -1;
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return c;
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}
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