diff options
Diffstat (limited to 'gnu/libexec/uucp/libunix/serial.c')
| -rw-r--r-- | gnu/libexec/uucp/libunix/serial.c | 259 |
1 files changed, 190 insertions, 69 deletions
diff --git a/gnu/libexec/uucp/libunix/serial.c b/gnu/libexec/uucp/libunix/serial.c index ae0a943..a38e28c 100644 --- a/gnu/libexec/uucp/libunix/serial.c +++ b/gnu/libexec/uucp/libunix/serial.c @@ -1,7 +1,7 @@ /* serial.c The serial port communication routines for Unix. - Copyright (C) 1991, 1992, 1993, 1994 Ian Lance Taylor + Copyright (C) 1991, 1992, 1993, 1994, 1995 Ian Lance Taylor This file is part of the Taylor UUCP package. @@ -17,16 +17,16 @@ You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author of the program may be contacted at ian@airs.com or - c/o Cygnus Support, Building 200, 1 Kendall Square, Cambridge, MA 02139. + c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144. */ #include "uucp.h" #if USE_RCS_ID -const char serial_rcsid[] = "$Id: serial.c,v 1.4 1994/05/07 18:11:09 ache Exp $"; +const char serial_rcsid[] = "$Id: serial.c,v 1.65 1995/08/10 00:53:54 ian Rel $"; #endif #include "uudefs.h" @@ -82,7 +82,7 @@ const char serial_rcsid[] = "$Id: serial.c,v 1.4 1994/05/07 18:11:09 ache Exp $" #include <sys/ioctl.h> #endif -#if HAVE_BSD_TTY +#if HAVE_SELECT #if HAVE_SYS_TIME_H #include <sys/time.h> #endif @@ -92,7 +92,7 @@ const char serial_rcsid[] = "$Id: serial.c,v 1.4 1994/05/07 18:11:09 ache Exp $" #endif #if HAVE_TIME_H -#if ! HAVE_SYS_TIME_H || ! HAVE_BSD_TTY || TIME_WITH_SYS_TIME +#if ! HAVE_SYS_TIME_H || ! HAVE_SELECT || TIME_WITH_SYS_TIME #include <time.h> #endif #endif @@ -517,6 +517,9 @@ boolean fsysdep_stdin_init (qconn) struct sconnection *qconn; { + /* chmod /dev/tty to prevent other users from writing messages to + it. This is essentially `mesg n'. */ + (void) chmod ("/dev/tty", S_IRUSR | S_IWUSR); return fsserial_init (qconn, &sstdincmds, (const char *) NULL); } @@ -647,7 +650,7 @@ fsserial_lockfile (flok, qconn) strerror (errno)); return FALSE; } - zalc = zbufalc (sizeof "LK.123.123.123"); + zalc = zbufalc (sizeof "LK.1234567890.1234567890.1234567890"); sprintf (zalc, "LK.%03d.%03d.%03d", major (s.st_dev), major (s.st_rdev), minor (s.st_rdev)); z = zalc; @@ -860,7 +863,7 @@ fsserial_unlock (qconn) } qsysdep->o = -1; } - + if (! fsserial_lockfile (FALSE, qconn)) fret = FALSE; @@ -1748,7 +1751,7 @@ fsmodem_carrier (qconn, fcarrier) return FALSE; #ifdef TIOCNCAR - /* Tell the modem to ignore carrier. */ + /* Tell the modem to ignore carrier. */ if (ioctl (q->o, TIOCNCAR, 0) < 0) { ulog (LOG_ERROR, "ioctl (TIOCNCAR): %s", strerror (errno)); @@ -1782,19 +1785,19 @@ fsmodem_carrier (qconn, fcarrier) ulog (LOG_ERROR, "Can't set CLOCAL: %s", strerror (errno)); return FALSE; } - + #if HAVE_CLOCAL_BUG /* On SCO and AT&T UNIX PC you have to reopen the port. */ { int onew; - + onew = open (q->zdevice, O_RDWR); if (onew < 0) { ulog (LOG_ERROR, "open (%s): %s", q->zdevice, strerror (errno)); return FALSE; } - + if (fcntl (onew, F_SETFD, fcntl (onew, F_GETFD, 0) | FD_CLOEXEC) < 0) { @@ -1817,8 +1820,9 @@ fsmodem_carrier (qconn, fcarrier) /* Tell the port to use hardware flow control. There is no standard mechanism for controlling this. This implementation supports CRTSCTS on SunOS, RTS/CTSFLOW on 386(ish) unix, CTSCD on the 3b1, - and TXADDCD/TXDELCD on AIX. If you know how to do it on other - systems, please implement it and send me the patches. */ + CCTS_OFLOW/CRTS_IFLOW on BSDI, TXADDCD/TXDELCD on AIX, and IRTS on + NCR Tower. If you know how to do it on other systems, please + implement it and send me the patches. */ static boolean fsserial_hardflow (qconn, fhardflow) @@ -1841,12 +1845,16 @@ fsserial_hardflow (qconn, fhardflow) #ifndef CRTSFL #ifndef CRTSCTS #ifndef CTSCD +#ifndef CCTS_OFLOW +#ifndef IRTS #define HAVE_HARDFLOW 0 #endif #endif #endif #endif #endif +#endif +#endif #ifndef HAVE_HARDFLOW #define HAVE_HARDFLOW 1 @@ -1871,6 +1879,12 @@ fsserial_hardflow (qconn, fhardflow) #ifdef CTSCD q->snew.c_cflag |= CTSCD; #endif /* defined (CTSCD) */ +#ifdef CCTS_OFLOW + q->snew.c_cflag |= CCTS_OFLOW | CRTS_IFLOW; +#endif +#ifdef IRTS + q->snew.c_iflag |= IRTS; +#endif #endif /* HAVE_SYSV_TERMIO || HAVE_POSIX_TERMIOS */ if (! fsetterminfo (q->o, &q->snew)) { @@ -1898,6 +1912,12 @@ fsserial_hardflow (qconn, fhardflow) #ifdef CTSCD q->snew.c_cflag &=~ CTSCD; #endif /* defined (CTSCD) */ +#ifdef CCTS_OFLOW + q->snew.c_cflag &=~ (CCTS_OFLOW | CRTS_IFLOW); +#endif +#ifdef IRTS + q->snew.c_iflag &=~ IRTS; +#endif #endif /* HAVE_SYSV_TERMIO || HAVE_POSIX_TERMIOS */ if (! fsetterminfo (q->o, &q->snew)) { @@ -2001,7 +2021,7 @@ fsysdep_modem_end_dial (qconn, qdial) errors. */ { int onew; - + onew = open (q->zdevice, O_RDWR); if (onew >= 0) { @@ -2039,7 +2059,7 @@ fsysdep_modem_end_dial (qconn, qdial) #endif /* ! defined (TIOCWONLINE) */ } - return TRUE; + return TRUE; } /* Read data from a connection, with a timeout. This routine handles @@ -2562,7 +2582,10 @@ fsysdep_conn_io (qconn, zwrite, pcwrite, zread, pcread) write up to SINGLE_WRITE bytes if all data written, return if no data written - blocked write of up to SINGLE_WRITE bytes + if select works + select on the write descriptor with a ten second timeout + else + blocked write of one byte with a ten second alarm This algorithm should work whether the system supports unblocked writes on terminals or not. If the system supports @@ -2572,7 +2595,28 @@ fsysdep_conn_io (qconn, zwrite, pcwrite, zread, pcread) then the write may hang so long that incoming data is lost. This is actually possible at high baud rates on any system when a blocking write is done; there is no solution, except - hardware handshaking. */ + hardware handshaking. + + If we were not able to write any data, then we need to block + until we can write something. The code used to simply do a + blocking write. However, that fails when a bidirectional + protocol is permitted to push out enough bytes to fill the + entire pipe between the two communicating uucico processes. + They can both block on writing, because neither is reading. + + In this case, we use select. We could select on both the + read and write descriptor, but on some systems that would + lead to calling read on each byte, which would be very + inefficient. Instead, we select only on the write + descriptor. After the select succeeds or times out, we retry + the read. + + Of course, some systems don't have select, and on some + systems that have it it doesn't work on terminal devices. If + we can't use select, then we do a blocked write of a single + byte after setting an alarm. We only write a single byte to + avoid any confusion as to whether or not the byte was + actually written. */ /* If we are running on standard input, we switch the file descriptors by hand. */ @@ -2717,38 +2761,105 @@ fsysdep_conn_io (qconn, zwrite, pcwrite, zread, pcread) } else { - /* We didn't write any data. Do a blocking write. */ - - if (q->ord >= 0) - q->o = q->ord; +#if HAVE_SELECT + struct timeval stime; + int imask; + int c; + + /* We didn't write any data. Call select. We use a timeout + long enough for 1024 bytes to be sent. + secs/kbyte == (1024 bytes/kbyte * 10 bits/byte) / baud bits/sec + usecs/kbyte == (((1024 bytes/kbyte * 1000000 usecs/sec) + / baud bits/sec) + * 10 bits/byte) + */ + stime.tv_sec = (long) 10240 / q->ibaud; + stime.tv_usec = ((((long) 1024000000 / q->ibaud) * (long) 10) + % (long) 1000000); + + imask = 1 << q->o; + if (imask == 0) + ulog (LOG_FATAL, "fsysdep_conn_io: File descriptors too large"); - if (! fsblock (q, TRUE)) + /* If we've received a signal, don't continue. */ + if (FGOT_QUIT_SIGNAL ()) return FALSE; - cdo = cwrite; - if (cdo > SINGLE_WRITE) - cdo = SINGLE_WRITE; + DEBUG_MESSAGE0 (DEBUG_PORT, "fsysdep_conn_io: Calling select"); - DEBUG_MESSAGE1 (DEBUG_PORT, - "fsysdep_conn_io: Blocking write of %lu", - (unsigned long) cdo); + /* We don't bother to loop on EINTR. If we get a signal, we + just loop around and try the read and write again. */ + c = select (q->o + 1, (pointer) NULL, (pointer) &imask, + (pointer) NULL, &stime); + if (c < 0 && errno == EINTR) + { + /* We got interrupted by a signal. Log it. */ + ulog (LOG_ERROR, (const char *) NULL); + } + else if (c >= 0) + { + /* The select either discovered that we could write + something, or it timed out. Either way, we go around + the main read/write loop again. */ + } + else +#endif /* HAVE_SELECT */ + { + int ierr; - if (q->owr >= 0) - q->o = q->owr; + /* Either the select failed for some reason other than + EINTR, or the system does not support select at all. + Fall back on a timed write. We don't worry about why + the select might have failed, we just assume that it + will not succeed on this descriptor. */ + +#if HAVE_RESTARTABLE_SYSCALLS + /* If HAVE_RESTARTABLE_SYSCALLS, then receiving an alarm + signal in the middle of a write will not cause the + write to return EINTR, and the only way to interrupt + the write is to longjmp out of it (see sysh.unx). + That is unreliable, because it means that we won't + know whether the byte was actually written or not. + However, I believe that the only system on which we + need to do this longjmp is BSD 4.2, and that system + supports select, so we should never execute this + case. */ + ulog (LOG_FATAL, "fsysdep_conn_io: Unsupported case; see code"); +#endif + + if (q->ord >= 0) + q->o = q->ord; + + if (! fsblock (q, TRUE)) + return FALSE; + + DEBUG_MESSAGE0 (DEBUG_PORT, "fsysdep_conn_io: Blocking write"); + + if (q->owr >= 0) + q->o = q->owr; - /* Loop until we get something besides EINTR. */ - while (TRUE) - { /* If we've received a signal, don't continue. */ if (FGOT_QUIT_SIGNAL ()) return FALSE; + /* Start up an alarm to interrupt the write. Note that + we don't need to use the catch stuff, since we know + that HAVE_RESTARTABLE_SYSCALLS is 0. */ + usset_signal (SIGALRM, usalarm, TRUE, (boolean *) NULL); + alarm ((int) ((long) 10240 / q->ibaud) + 1); + + /* There is a race condition here: on a severely loaded + system, we could get the alarm before we start the + write call. This would not be a disaster; often the + write will succeed anyhow. */ #if HAVE_TLI if (q->ftli) { - cdid = t_snd (q->o, (char *) zwrite, cdo, 0); + cdid = t_snd (q->o, (char *) zwrite, 1, 0); if (cdid < 0 && t_errno != TSYSERR) { + usset_signal (SIGALRM, SIG_IGN, TRUE, (boolean *) NULL); + alarm (0); ulog (LOG_ERROR, "t_snd: %s", (t_errno >= 0 && t_errno < t_nerr ? t_errlist[t_errno] @@ -2758,44 +2869,54 @@ fsysdep_conn_io (qconn, zwrite, pcwrite, zread, pcread) } else #endif - cdid = write (q->o, zwrite, cdo); + cdid = write (q->o, zwrite, 1); - if (cdid >= 0) - break; - if (errno != EINTR) - break; + ierr = errno; - /* We got interrupted by a signal. Log it. */ - ulog (LOG_ERROR, (const char *) NULL); - } + /* Note that we don't really care whether the write + finished because the byte was written out or whether + it finished because the alarm was triggered. Either + way, we are going to loop around and try another + read. */ - if (cdid < 0) - { - ulog (LOG_ERROR, "write: %s", strerror (errno)); - return FALSE; - } + usset_signal (SIGALRM, SIG_IGN, TRUE, (boolean *) NULL); + alarm (0); - if (cdid == 0) - { - /* On some systems write will return 0 if carrier is - lost. If we fail to write anything ten times in a - row, we assume that this has happened. This is - hacked in like this because there seems to be no - reliable way to tell exactly why the write returned - 0. */ - ++czero; - if (czero >= 10) + if (cdid < 0) { - ulog (LOG_ERROR, "Line disconnected"); - return FALSE; + if (ierr == EINTR) + { + /* We got interrupted by a signal. Log it. */ + ulog (LOG_ERROR, (const char *) NULL); + } + else + { + ulog (LOG_ERROR, "write: %s", strerror (ierr)); + return FALSE; + } + } + else if (cdid == 0) + { + /* On some systems write will return 0 if carrier is + lost. If we fail to write anything ten times in + a row, we assume that this has happened. This is + hacked in like this because there seems to be no + reliable way to tell exactly why the write + returned 0. */ + ++czero; + if (czero >= 10) + { + ulog (LOG_ERROR, "Line disconnected"); + return FALSE; + } + } + else + { + cwrite -= cdid; + zwrite += cdid; + *pcwrite += cdid; + czero = 0; } - } - else - { - cwrite -= cdid; - zwrite += cdid; - *pcwrite += cdid; - czero = 0; } } } @@ -2937,7 +3058,7 @@ fsserial_set (qconn, tparity, tstrip, txonxoff) /* Not supported. */ break; } - + if (fdo) { if ((q->snew.c_cflag & iset) != iset @@ -2973,7 +3094,7 @@ fsserial_set (qconn, tparity, tstrip, txonxoff) } #endif -#else /* ! HAVE_BSD_TTY */ +#else /* ! HAVE_BSD_TTY */ fdo = FALSE; switch (tstrip) |
