+
+/*
+ * start_charshunt - create a child process to run the character shunt.
+ */
+static int
+start_charshunt(ifd, ofd)
+ int ifd, ofd;
+{
+ int cpid;
+
+ cpid = fork();
+ if (cpid == -1) {
+ error("Can't fork process for character shunt: %m");
+ return 0;
+ }
+ if (cpid == 0) {
+ /* child */
+ close(pty_slave);
+ setuid(uid);
+ if (getuid() != uid)
+ fatal("setuid failed");
+ setgid(getgid());
+ if (!nodetach)
+ log_to_fd = -1;
+ charshunt(ifd, ofd, record_file);
+ exit(0);
+ }
+ charshunt_pid = cpid;
+ close(pty_master);
+ pty_master = -1;
+ ttyfd = pty_slave;
+ record_child(cpid, "pppd (charshunt)", charshunt_done, NULL);
+ return 1;
+}
+
+static void
+charshunt_done(arg)
+ void *arg;
+{
+ charshunt_pid = 0;
+}
+
+/*
+ * charshunt - the character shunt, which passes characters between
+ * the pty master side and the serial port (or stdin/stdout).
+ * This runs as the user (not as root).
+ * (We assume ofd >= ifd which is true the way this gets called. :-).
+ */
+static void
+charshunt(ifd, ofd, record_file)
+ int ifd, ofd;
+ char *record_file;
+{
+ int n, nfds;
+ fd_set ready, writey;
+ u_char *ibufp, *obufp;
+ int nibuf, nobuf;
+ int flags;
+ int pty_readable, stdin_readable;
+ struct timeval lasttime;
+ FILE *recordf = NULL;
+
+ /*
+ * Reset signal handlers.
+ */
+ signal(SIGHUP, SIG_IGN); /* Hangup */
+ signal(SIGINT, SIG_DFL); /* Interrupt */
+ signal(SIGTERM, SIG_DFL); /* Terminate */
+ signal(SIGCHLD, SIG_DFL);
+ signal(SIGUSR1, SIG_DFL);
+ signal(SIGUSR2, SIG_DFL);
+ signal(SIGABRT, SIG_DFL);
+ signal(SIGALRM, SIG_DFL);
+ signal(SIGFPE, SIG_DFL);
+ signal(SIGILL, SIG_DFL);
+ signal(SIGPIPE, SIG_DFL);
+ signal(SIGQUIT, SIG_DFL);
+ signal(SIGSEGV, SIG_DFL);
+#ifdef SIGBUS
+ signal(SIGBUS, SIG_DFL);
+#endif
+#ifdef SIGEMT
+ signal(SIGEMT, SIG_DFL);
+#endif
+#ifdef SIGPOLL
+ signal(SIGPOLL, SIG_DFL);
+#endif
+#ifdef SIGPROF
+ signal(SIGPROF, SIG_DFL);
+#endif
+#ifdef SIGSYS
+ signal(SIGSYS, SIG_DFL);
+#endif
+#ifdef SIGTRAP
+ signal(SIGTRAP, SIG_DFL);
+#endif
+#ifdef SIGVTALRM
+ signal(SIGVTALRM, SIG_DFL);
+#endif
+#ifdef SIGXCPU
+ signal(SIGXCPU, SIG_DFL);
+#endif
+#ifdef SIGXFSZ
+ signal(SIGXFSZ, SIG_DFL);
+#endif
+
+ /*
+ * Open the record file if required.
+ */
+ if (record_file != NULL) {
+ recordf = fopen(record_file, "a");
+ if (recordf == NULL)
+ error("Couldn't create record file %s: %m", record_file);
+ }
+
+ /* set all the fds to non-blocking mode */
+ flags = fcntl(pty_master, F_GETFL);
+ if (flags == -1
+ || fcntl(pty_master, F_SETFL, flags | O_NONBLOCK) == -1)
+ warn("couldn't set pty master to nonblock: %m");
+ flags = fcntl(ifd, F_GETFL);
+ if (flags == -1
+ || fcntl(ifd, F_SETFL, flags | O_NONBLOCK) == -1)
+ warn("couldn't set %s to nonblock: %m", (ifd==0? "stdin": "tty"));
+ if (ofd != ifd) {
+ flags = fcntl(ofd, F_GETFL);
+ if (flags == -1
+ || fcntl(ofd, F_SETFL, flags | O_NONBLOCK) == -1)
+ warn("couldn't set stdout to nonblock: %m");
+ }
+
+ nibuf = nobuf = 0;
+ ibufp = obufp = NULL;
+ pty_readable = stdin_readable = 1;
+ nfds = (ofd > pty_master? ofd: pty_master) + 1;
+ if (recordf != NULL) {
+ gettimeofday(&lasttime, NULL);
+ putc(7, recordf); /* put start marker */
+ putc(lasttime.tv_sec >> 24, recordf);
+ putc(lasttime.tv_sec >> 16, recordf);
+ putc(lasttime.tv_sec >> 8, recordf);
+ putc(lasttime.tv_sec, recordf);
+ lasttime.tv_usec = 0;
+ }
+
+ while (nibuf != 0 || nobuf != 0 || pty_readable || stdin_readable) {
+ FD_ZERO(&ready);
+ FD_ZERO(&writey);
+ if (nibuf != 0)
+ FD_SET(pty_master, &writey);
+ else if (stdin_readable)
+ FD_SET(ifd, &ready);
+ if (nobuf != 0)
+ FD_SET(ofd, &writey);
+ else if (pty_readable)
+ FD_SET(pty_master, &ready);
+ if (select(nfds, &ready, &writey, NULL, NULL) < 0) {
+ if (errno != EINTR)
+ fatal("select");
+ continue;
+ }
+ if (FD_ISSET(ifd, &ready)) {
+ ibufp = inpacket_buf;
+ nibuf = read(ifd, ibufp, sizeof(inpacket_buf));
+ if (nibuf < 0 && errno == EIO)
+ nibuf = 0;
+ if (nibuf < 0) {
+ if (!(errno == EINTR || errno == EAGAIN)) {
+ error("Error reading standard input: %m");
+ break;
+ }
+ nibuf = 0;
+ } else if (nibuf == 0) {
+ /* end of file from stdin */
+ stdin_readable = 0;
+ /* do a 0-length write, hopefully this will generate
+ an EOF (hangup) on the slave side. */
+ write(pty_master, inpacket_buf, 0);
+ if (recordf)
+ if (!record_write(recordf, 4, NULL, 0, &lasttime))
+ recordf = NULL;
+ } else {
+ FD_SET(pty_master, &writey);
+ if (recordf)
+ if (!record_write(recordf, 2, ibufp, nibuf, &lasttime))
+ recordf = NULL;
+ }
+ }
+ if (FD_ISSET(pty_master, &ready)) {
+ obufp = outpacket_buf;
+ nobuf = read(pty_master, obufp, sizeof(outpacket_buf));
+ if (nobuf < 0 && errno == EIO)
+ nobuf = 0;
+ if (nobuf < 0) {
+ if (!(errno == EINTR || errno == EAGAIN)) {
+ error("Error reading pseudo-tty master: %m");
+ break;
+ }
+ nobuf = 0;
+ } else if (nobuf == 0) {
+ /* end of file from the pty - slave side has closed */
+ pty_readable = 0;
+ stdin_readable = 0; /* pty is not writable now */
+ nibuf = 0;
+ close(ofd);
+ if (recordf)
+ if (!record_write(recordf, 3, NULL, 0, &lasttime))
+ recordf = NULL;
+ } else {
+ FD_SET(ofd, &writey);
+ if (recordf)
+ if (!record_write(recordf, 1, obufp, nobuf, &lasttime))
+ recordf = NULL;
+ }
+ }
+ if (FD_ISSET(ofd, &writey)) {
+ n = write(ofd, obufp, nobuf);
+ if (n < 0) {
+ if (errno != EIO) {
+ error("Error writing standard output: %m");
+ break;
+ }
+ pty_readable = 0;
+ nobuf = 0;
+ } else {
+ obufp += n;
+ nobuf -= n;
+ }
+ }
+ if (FD_ISSET(pty_master, &writey)) {
+ n = write(pty_master, ibufp, nibuf);
+ if (n < 0) {
+ if (errno != EIO) {
+ error("Error writing pseudo-tty master: %m");
+ break;
+ }
+ stdin_readable = 0;
+ nibuf = 0;
+ } else {
+ ibufp += n;
+ nibuf -= n;
+ }
+ }
+ }
+ exit(0);
+}
+
+static int
+record_write(f, code, buf, nb, tp)
+ FILE *f;
+ int code;
+ u_char *buf;
+ int nb;
+ struct timeval *tp;
+{
+ struct timeval now;
+ int diff;
+
+ gettimeofday(&now, NULL);
+ now.tv_usec /= 100000; /* actually 1/10 s, not usec now */
+ diff = (now.tv_sec - tp->tv_sec) * 10 + (now.tv_usec - tp->tv_usec);
+ if (diff > 0) {
+ if (diff > 255) {
+ putc(5, f);
+ putc(diff >> 24, f);
+ putc(diff >> 16, f);
+ putc(diff >> 8, f);
+ putc(diff, f);
+ } else {
+ putc(6, f);
+ putc(diff, f);
+ }
+ *tp = now;
+ }
+ putc(code, f);
+ if (buf != NULL) {
+ putc(nb >> 8, f);
+ putc(nb, f);
+ fwrite(buf, nb, 1, f);
+ }
+ fflush(f);
+ if (ferror(f)) {
+ error("Error writing record file: %m");
+ return 0;
+ }
+ return 1;
+}