21bfcc9f8c
established. This way, automatic scripts are possible that might control the SLIP connection. It's unacceptable for a daemon that's being controlled by a variety of signals to not leave its PID somewhere. The file name contains the terminal path name component of the associated tty device, so it should be unique even with multiple parallel slattach's running. The file will be unlinked at regular exit. Also found a minor bug in the option handling by compiling with -Wall.
475 lines
14 KiB
C
475 lines
14 KiB
C
/*
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* Copyright (c) 1988 Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Rick Adams.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char copyright[] =
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"@(#) Copyright (c) 1988 Regents of the University of California.\n\
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All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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/*static char sccsid[] = "from: @(#)slattach.c 4.6 (Berkeley) 6/1/90";*/
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static char rcsid[] = "$Id";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <termios.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <net/if.h>
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#include <net/slip.h>
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#include <net/if_slvar.h>
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#include <netdb.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <paths.h>
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#include <syslog.h>
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#include <signal.h>
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#include <strings.h>
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#define DEFAULT_BAUD 9600
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void sighup_handler(); /* SIGHUP handler */
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void sigint_handler(); /* SIGINT handler */
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void sigterm_handler(); /* SIGTERM handler */
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void exit_handler(int ret); /* run exit_cmd iff specified upon exit. */
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void setup_line(int cflag); /* configure terminal settings */
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void slip_discipline(); /* switch to slip line discipline */
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void configure_network(); /* configure slip interface */
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void acquire_line(); /* get tty device as controling terminal */
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int fd = -1;
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char *dev = (char *)0; /* path name of the tty (e.g. /dev/tty01) */
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int flow_control = 0; /* non-zero to enable hardware flow control. */
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int modem_control = HUPCL; /* !CLOCAL+HUPCL iff we watch carrier. */
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int comstate; /* TIOCMGET current state of serial driver */
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int redial_on_startup = 0; /* iff non-zero execute redial_cmd on startup */
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int speed = DEFAULT_BAUD; /* baud rate of tty */
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int slflags = 0; /* compression flags */
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int unit = -1; /* slip device unit number */
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int foreground = 0; /* act as demon if zero, else don't fork. */
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int exiting = 0; /* allready running exit_handler */
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struct termios tty; /* tty configuration/state */
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char tty_path[32]; /* path name of the tty (e.g. /dev/tty01) */
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char pidfilename[40]; /* e.g. /var/run/slattach.tty01.pid */
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char *redial_cmd = 0; /* command to exec upon shutdown. */
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char *config_cmd = 0; /* command to exec if slip unit changes. */
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char *exit_cmd = 0; /* command to exec before exiting. */
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static char usage_str[] = "\
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usage: %s [-acfhlnz] [-e command] [-r command] [-s speed] [-u command] device\n\
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-a -- autoenable VJ compression\n\
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-c -- enable VJ compression\n\
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-e ECMD -- run ECMD before exiting\n\
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-f -- run in foreground (don't detach from controlling tty)\n\
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-h -- turn on cts/rts style flow control\n\
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-l -- disable modem control (CLOCAL) and ignore carrier detect\n\
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-n -- throw out ICMP packets\n\
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-r RCMD -- run RCMD upon loss of carrier\n\
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-s # -- set baud rate (default 9600)\n\
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-u UCMD -- run 'UCMD <old sl#> <new sl#>' before switch to slip discipline\n\
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-z -- run RCMD upon startup irrespective of carrier\n";
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int main(int argc, char **argv)
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{
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int option;
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extern char *optarg;
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extern int optind;
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char *cp;
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while ((option = getopt(argc, argv, "ace:fhlnr:s:u:z")) != EOF) {
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switch (option) {
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case 'a':
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slflags |= IFF_LINK2;
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slflags &= ~IFF_LINK0;
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break;
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case 'c':
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slflags |= IFF_LINK0;
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slflags &= ~IFF_LINK2;
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break;
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case 'e':
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exit_cmd = (char*) strdup (optarg);
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break;
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case 'f':
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foreground = 1;
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break;
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case 'h':
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flow_control |= CRTSCTS;
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break;
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case 'l':
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modem_control = CLOCAL; /* clear HUPCL too */
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break;
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case 'n':
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slflags |= IFF_LINK1;
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break;
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case 'r':
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redial_cmd = (char*) strdup (optarg);
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break;
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case 's':
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speed = atoi(optarg);
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break;
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case 'u':
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config_cmd = (char*) strdup (optarg);
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break;
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case 'z':
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redial_on_startup = 1;
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break;
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default:
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fprintf(stderr, "%s: Invalid option -- '%c'\n",
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argv[0], option);
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case '?':
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fprintf(stderr, usage_str, argv[0]);
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exit_handler(1);
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}
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}
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if (optind == argc - 1)
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dev = argv[optind];
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if (optind < (argc - 1)) {
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fprintf(stderr, "%s: Too many args, first='%s'\n",
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argv[0], argv[optind]);
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}
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if (optind > (argc - 1)) {
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fprintf(stderr, "%s: Not enough args\n", argv[0]);
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}
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if (dev == (char *)0) {
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fprintf(stderr, usage_str, argv[0]);
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exit_handler(2);
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}
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if (strncmp(_PATH_DEV, dev, sizeof(_PATH_DEV) - 1)) {
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strcpy(tty_path, _PATH_DEV);
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strcat(tty_path, "/");
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strncat(tty_path, dev, 10);
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dev = tty_path;
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}
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cp = strrchr(dev, '/'); /* always succeeds */
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cp++; /* trailing tty pathname component */
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sprintf(pidfilename, "%sslattach.%s.pid", _PATH_VARRUN, cp);
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printf("%s\n",pidfilename);
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if (!foreground)
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daemon(0,0); /* fork, setsid, chdir /, and close std*. */
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/* daemon() closed stderr, so log errors from here on. */
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openlog("slattach",LOG_CONS|LOG_PID,LOG_DAEMON);
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acquire_line(); /* get tty device as controling terminal */
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setup_line(0); /* configure for slip line discipline */
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slip_discipline(); /* switch to slip line discipline */
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/* upon INT log a timestamp and exit. */
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if ((int)signal(SIGINT,sigint_handler) < 0)
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syslog(LOG_NOTICE,"cannot install SIGINT handler: %m");
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/* upon TERM log a timestamp and exit. */
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if ((int)signal(SIGTERM,sigterm_handler) < 0)
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syslog(LOG_NOTICE,"cannot install SIGTERM handler: %m");
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/* upon HUP redial and reconnect. */
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if ((int)signal(SIGHUP,sighup_handler) < 0)
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syslog(LOG_NOTICE,"cannot install SIGHUP handler: %m");
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if (redial_on_startup)
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sighup_handler();
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else if (!(modem_control & CLOCAL)) {
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if (ioctl(fd, TIOCMGET, &comstate) < 0)
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syslog(LOG_NOTICE,"cannot get carrier state: %m");
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if (!(comstate & TIOCM_CD)) { /* check for carrier */
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/* force a redial if no carrier */
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kill (getpid(), SIGHUP);
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} else
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configure_network();
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}
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else
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configure_network(); /* configure the network if needed. */
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for (;;) {
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sigset_t mask;
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sigemptyset(&mask);
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sigsuspend(&mask);
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}
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}
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/* Close all FDs, fork, reopen tty port as 0-2, and make it the
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controlling terminal for our process group. */
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void acquire_line()
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{
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int ttydisc = TTYDISC;
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FILE *pidfile;
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ioctl(fd, TIOCSETD, &ttydisc); /* reset to tty discipline */
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(void)close(STDIN_FILENO); /* close FDs before forking. */
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(void)close(STDOUT_FILENO);
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(void)close(STDERR_FILENO);
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if (fd > 2)
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(void)close(fd);
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signal(SIGHUP, SIG_IGN); /* ignore HUP signal when parent dies. */
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daemon(0,0); /* fork, setsid, chdir /, and close std*. */
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while (getppid () != 1)
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sleep (1); /* Wait for parent to die. */
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/* create PID file */
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if((pidfile = fopen(pidfilename, "w")) == NULL) {
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syslog(LOG_NOTICE,"cannot create PID file: %m");
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} else {
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fprintf(pidfile, "%ld\n", getpid());
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fclose(pidfile);
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}
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if ((int)signal(SIGHUP,sighup_handler) < 0) /* Re-enable HUP signal */
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syslog(LOG_NOTICE,"cannot install SIGHUP handler: %m");
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if ((fd = open(dev, O_RDWR | O_NONBLOCK, 0)) < 0) {
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syslog(LOG_ERR, "open(%s) fd=%d: %m", dev, fd);
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exit_handler(1);
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}
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(void)dup2(fd, STDIN_FILENO);
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(void)dup2(fd, STDOUT_FILENO);
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(void)dup2(fd, STDERR_FILENO);
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if (fd > 2)
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(void)close (fd);
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fd = STDIN_FILENO;
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/* acquire the serial line as a controling terminal. */
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if (ioctl(fd, TIOCSCTTY, 0) < 0)
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syslog(LOG_NOTICE,"ioctl(TIOCSCTTY) failed: %m");
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/* Make us the foreground process group associated with the
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slip line which is our controlling terminal. */
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if (tcsetpgrp(fd, getpid()) < 0)
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syslog(LOG_NOTICE,"tcsetpgrp failed: %m");
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}
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/* Set the tty flags and set DTR. */
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/* Call as setup_line(CLOCAL) to force clocal assertion. */
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void setup_line(int cflag)
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{
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tty.c_lflag = tty.c_iflag = tty.c_oflag = 0;
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tty.c_cflag = CREAD | CS8 | flow_control | modem_control | cflag;
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tty.c_ispeed = tty.c_ospeed = speed;
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/* set the line speed and flow control */
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if (tcsetattr(fd, TCSAFLUSH, &tty) < 0) {
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syslog(LOG_ERR, "tcsetattr(TCSAFLUSH): %m");
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exit_handler(1);
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}
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/* set data terminal ready */
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if (ioctl(fd, TIOCSDTR) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCSDTR): %m");
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exit_handler(1);
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}
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}
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/* Put the line in slip discipline. */
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void slip_discipline()
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{
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struct ifreq ifr;
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int slipdisc = SLIPDISC;
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int s, tmp_unit = -1;
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/* Switch to slip line discipline. */
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if (ioctl(fd, TIOCSETD, &slipdisc) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCSETD): %m");
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exit_handler(1);
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}
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/* find out what unit number we were assigned */
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if (ioctl(fd, SLIOCGUNIT, (caddr_t)&tmp_unit) < 0) {
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syslog(LOG_ERR, "ioctl(SLIOCGUNIT): %m");
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exit_handler(1);
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}
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if (tmp_unit < 0) {
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syslog(LOG_ERR, "bad unit (%d) from ioctl(SLIOCGUNIT)",tmp_unit);
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exit_handler(1);
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}
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/* open a socket as the handle to the interface */
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s = socket(AF_INET, SOCK_DGRAM, 0);
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if (s < 0) {
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syslog(LOG_ERR, "socket: %m");
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exit_handler(1);
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}
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sprintf(ifr.ifr_name, "sl%d", tmp_unit);
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/* get the flags for the interface */
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if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
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syslog(LOG_ERR, "ioctl (SIOCGIFFLAGS): %m");
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exit_handler(1);
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}
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/* Assert any compression or no-icmp flags. */
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#define SLMASK (~(IFF_LINK0 | IFF_LINK1 | IFF_LINK2))
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ifr.ifr_flags &= SLMASK;
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ifr.ifr_flags |= slflags;
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if (ioctl(s, SIOCSIFFLAGS, (caddr_t)&ifr) < 0) {
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syslog(LOG_ERR, "ioctl (SIOCSIFFLAGS): %m");
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exit_handler(1);
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}
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close(s);
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}
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/* configure the interface, eg. by passing the unit number to a script. */
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void configure_network()
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{
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int new_unit;
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/* find out what unit number we were assigned */
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if (ioctl(fd, SLIOCGUNIT, (caddr_t)&new_unit) < 0) {
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syslog(LOG_ERR, "ioctl(SLIOCGUNIT): %m");
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exit_handler(1);
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}
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/* don't compare unit numbers if this is the first time to attach. */
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if (unit < 0)
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unit = new_unit;
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/* iff the unit number changes either invoke config_cmd or punt. */
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if (config_cmd) {
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char *s;
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s = (char*) malloc(strlen(config_cmd) + 32);
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sprintf (s, "%s %d %d", config_cmd, unit, new_unit);
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syslog(LOG_NOTICE, "Configuring %s (sl%d):", dev, unit);
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syslog(LOG_NOTICE, " '%s'", s);
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system(s);
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free (s);
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unit = new_unit;
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} else {
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if (new_unit != unit) {
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syslog(LOG_ERR, "slip unit changed from sl%d to sl%d, but no -u CMD was specified!");
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exit_handler(1);
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}
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syslog(LOG_NOTICE,"sl%d connected to %s at %d baud",unit,dev,speed);
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}
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}
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/* signup_handler() is invoked when carrier drops, eg. before redial. */
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void sighup_handler()
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{
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if(exiting) return;
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again:
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/* invoke a shell for redial_cmd or punt. */
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if (redial_cmd) {
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acquire_line();
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setup_line(CLOCAL);
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syslog(LOG_NOTICE,"SIGHUP on %s (sl%d); running %s",
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dev,unit,redial_cmd);
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if (system(redial_cmd))
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goto again;
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/* Now check again for carrier (dial command is done): */
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if (!(modem_control & CLOCAL)) {
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tty.c_cflag &= ~CLOCAL;
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if (tcsetattr(fd, TCSAFLUSH, &tty) < 0) {
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syslog(LOG_ERR, "tcsetattr(TCSAFLUSH): %m");
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exit_handler(1);
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}
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ioctl(fd, TIOCMGET, &comstate);
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if (!(comstate & TIOCM_CD)) { /* check for carrier */
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/* force a redial if no carrier */
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goto again;
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}
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}
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} else {
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/* If modem control, just wait for carrier before attaching.
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If no modem control, just fall through immediately. */
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if (!(modem_control & CLOCAL)) {
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int carrier = 0;
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syslog(LOG_NOTICE, "Waiting for carrier on %s (sl%d)",
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dev, unit);
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/* Now wait for carrier before attaching line. */
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/* We must poll since CLOCAL prevents signal. */
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while (! carrier) {
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sleep(2);
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ioctl(fd, TIOCMGET, &comstate);
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if (comstate & TIOCM_CD)
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carrier = 1;
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}
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syslog(LOG_NOTICE, "Carrier now present on %s (sl%d)",
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dev, unit);
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}
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}
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setup_line(0);
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slip_discipline();
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configure_network();
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}
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/* Signal handler for SIGINT. We just log and exit. */
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void sigint_handler()
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{
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if(exiting) return;
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syslog(LOG_NOTICE,"SIGINT on %s (sl%d); exiting",dev,unit);
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exit_handler(0);
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}
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/* Signal handler for SIGTERM. We just log and exit. */
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void sigterm_handler()
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{
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if(exiting) return;
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syslog(LOG_NOTICE,"SIGTERM on %s (sl%d); exiting",dev,unit);
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exit_handler(0);
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}
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/* Run config_cmd if specified before exiting. */
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void exit_handler(int ret)
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{
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if(exiting) return;
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exiting = 1;
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/*
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* First close the slip line in case exit_cmd wants it (like to hang
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* up a modem or something).
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*/
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if (fd != -1)
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close(fd);
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/* Remove the PID file */
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(void)unlink(pidfilename);
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/* invoke a shell for exit_cmd. */
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if (exit_cmd) {
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syslog(LOG_NOTICE,"exiting after running %s", exit_cmd);
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system(exit_cmd);
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}
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exit(ret);
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}
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/* local variables: */
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/* c-indent-level: 8 */
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/* c-argdecl-indent: 0 */
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/* c-label-offset: -8 */
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/* c-continued-statement-offset: 8 */
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/* c-brace-offset: 0 */
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/* comment-column: 32 */
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/* end: */
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