The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_ttydisc.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Portions of this software were developed under sponsorship from Snow
    6  * B.V., the Netherlands.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD$");
   32 
   33 #include <sys/param.h>
   34 #include <sys/fcntl.h>
   35 #include <sys/filio.h>
   36 #include <sys/kernel.h>
   37 #include <sys/signal.h>
   38 #include <sys/sysctl.h>
   39 #include <sys/systm.h>
   40 #include <sys/tty.h>
   41 #include <sys/ttycom.h>
   42 #include <sys/ttydefaults.h>
   43 #include <sys/uio.h>
   44 #include <sys/vnode.h>
   45 
   46 /*
   47  * Standard TTYDISC `termios' line discipline.
   48  */
   49 
   50 /* Statistics. */
   51 static unsigned long tty_nin = 0;
   52 SYSCTL_ULONG(_kern, OID_AUTO, tty_nin, CTLFLAG_RD,
   53         &tty_nin, 0, "Total amount of bytes received");
   54 static unsigned long tty_nout = 0;
   55 SYSCTL_ULONG(_kern, OID_AUTO, tty_nout, CTLFLAG_RD,
   56         &tty_nout, 0, "Total amount of bytes transmitted");
   57 
   58 /* termios comparison macro's. */
   59 #define CMP_CC(v,c) (tp->t_termios.c_cc[v] != _POSIX_VDISABLE && \
   60                         tp->t_termios.c_cc[v] == (c))
   61 #define CMP_FLAG(field,opt) (tp->t_termios.c_ ## field ## flag & (opt))
   62 
   63 /* Characters that cannot be modified through c_cc. */
   64 #define CTAB    '\t'
   65 #define CNL     '\n'
   66 #define CCR     '\r'
   67 
   68 /* Character is a control character. */
   69 #define CTL_VALID(c)    ((c) == 0x7f || (unsigned char)(c) < 0x20)
   70 /* Control character should be processed on echo. */
   71 #define CTL_ECHO(c,q)   (!(q) && ((c) == CERASE2 || (c) == CTAB || \
   72     (c) == CNL || (c) == CCR))
   73 /* Control character should be printed using ^X notation. */
   74 #define CTL_PRINT(c,q)  ((c) == 0x7f || ((unsigned char)(c) < 0x20 && \
   75     ((q) || ((c) != CTAB && (c) != CNL))))
   76 /* Character is whitespace. */
   77 #define CTL_WHITE(c)    ((c) == ' ' || (c) == CTAB)
   78 /* Character is alphanumeric. */
   79 #define CTL_ALNUM(c)    (((c) >= '' && (c) <= '9') || \
   80     ((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
   81 
   82 #define TTY_STACKBUF    256
   83 
   84 void
   85 ttydisc_open(struct tty *tp)
   86 {
   87         ttydisc_optimize(tp);
   88 }
   89 
   90 void
   91 ttydisc_close(struct tty *tp)
   92 {
   93 
   94         /* Clean up our flags when leaving the discipline. */
   95         tp->t_flags &= ~(TF_STOPPED|TF_HIWAT|TF_ZOMBIE);
   96 
   97         /* POSIX states we should flush when close() is called. */
   98         ttyinq_flush(&tp->t_inq);
   99         ttyoutq_flush(&tp->t_outq);
  100 
  101         if (!tty_gone(tp)) {
  102                 ttydevsw_inwakeup(tp);
  103                 ttydevsw_outwakeup(tp);
  104         }
  105 
  106         if (ttyhook_hashook(tp, close))
  107                 ttyhook_close(tp);
  108 }
  109 
  110 static int
  111 ttydisc_read_canonical(struct tty *tp, struct uio *uio, int ioflag)
  112 {
  113         char breakc[4] = { CNL }; /* enough to hold \n, VEOF and VEOL. */
  114         int error;
  115         size_t clen, flen = 0, n = 1;
  116         unsigned char lastc = _POSIX_VDISABLE;
  117 
  118 #define BREAK_ADD(c) do { \
  119         if (tp->t_termios.c_cc[c] != _POSIX_VDISABLE)   \
  120                 breakc[n++] = tp->t_termios.c_cc[c];    \
  121 } while (0)
  122         /* Determine which characters we should trigger on. */
  123         BREAK_ADD(VEOF);
  124         BREAK_ADD(VEOL);
  125 #undef BREAK_ADD
  126         breakc[n] = '\0';
  127 
  128         do {
  129                 error = tty_wait_background(tp, curthread, SIGTTIN);
  130                 if (error)
  131                         return (error);
  132 
  133                 /*
  134                  * Quite a tricky case: unlike the old TTY
  135                  * implementation, this implementation copies data back
  136                  * to userspace in large chunks. Unfortunately, we can't
  137                  * calculate the line length on beforehand if it crosses
  138                  * ttyinq_block boundaries, because multiple reads could
  139                  * then make this code read beyond the newline.
  140                  *
  141                  * This is why we limit the read to:
  142                  * - The size the user has requested
  143                  * - The blocksize (done in tty_inq.c)
  144                  * - The amount of bytes until the newline
  145                  *
  146                  * This causes the line length to be recalculated after
  147                  * each block has been copied to userspace. This will
  148                  * cause the TTY layer to return data in chunks using
  149                  * the blocksize (except the first and last blocks).
  150                  */
  151                 clen = ttyinq_findchar(&tp->t_inq, breakc, uio->uio_resid,
  152                     &lastc);
  153 
  154                 /* No more data. */
  155                 if (clen == 0) {
  156                         if (tp->t_flags & TF_ZOMBIE)
  157                                 return (0);
  158                         else if (ioflag & IO_NDELAY)
  159                                 return (EWOULDBLOCK);
  160 
  161                         error = tty_wait(tp, &tp->t_inwait);
  162                         if (error)
  163                                 return (error);
  164                         continue;
  165                 }
  166 
  167                 /* Don't send the EOF char back to userspace. */
  168                 if (CMP_CC(VEOF, lastc))
  169                         flen = 1;
  170 
  171                 MPASS(flen <= clen);
  172 
  173                 /* Read and throw away the EOF character. */
  174                 error = ttyinq_read_uio(&tp->t_inq, tp, uio, clen, flen);
  175                 if (error)
  176                         return (error);
  177 
  178         } while (uio->uio_resid > 0 && lastc == _POSIX_VDISABLE);
  179 
  180         return (0);
  181 }
  182 
  183 static int
  184 ttydisc_read_raw_no_timer(struct tty *tp, struct uio *uio, int ioflag)
  185 {
  186         size_t vmin = tp->t_termios.c_cc[VMIN];
  187         ssize_t oresid = uio->uio_resid;
  188         int error;
  189 
  190         MPASS(tp->t_termios.c_cc[VTIME] == 0);
  191 
  192         /*
  193          * This routine implements the easy cases of read()s while in
  194          * non-canonical mode, namely case B and D, where we don't have
  195          * any timers at all.
  196          */
  197 
  198         for (;;) {
  199                 error = tty_wait_background(tp, curthread, SIGTTIN);
  200                 if (error)
  201                         return (error);
  202 
  203                 error = ttyinq_read_uio(&tp->t_inq, tp, uio,
  204                     uio->uio_resid, 0);
  205                 if (error)
  206                         return (error);
  207                 if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
  208                         return (0);
  209 
  210                 /* We have to wait for more. */
  211                 if (tp->t_flags & TF_ZOMBIE)
  212                         return (0);
  213                 else if (ioflag & IO_NDELAY)
  214                         return (EWOULDBLOCK);
  215 
  216                 error = tty_wait(tp, &tp->t_inwait);
  217                 if (error)
  218                         return (error);
  219         }
  220 }
  221 
  222 static int
  223 ttydisc_read_raw_read_timer(struct tty *tp, struct uio *uio, int ioflag,
  224     int oresid)
  225 {
  226         size_t vmin = MAX(tp->t_termios.c_cc[VMIN], 1);
  227         unsigned int vtime = tp->t_termios.c_cc[VTIME];
  228         struct timeval end, now, left;
  229         int error, hz;
  230 
  231         MPASS(tp->t_termios.c_cc[VTIME] != 0);
  232 
  233         /* Determine when the read should be expired. */
  234         end.tv_sec = vtime / 10;
  235         end.tv_usec = (vtime % 10) * 100000;
  236         getmicrotime(&now);
  237         timevaladd(&end, &now);
  238 
  239         for (;;) {
  240                 error = tty_wait_background(tp, curthread, SIGTTIN);
  241                 if (error)
  242                         return (error);
  243 
  244                 error = ttyinq_read_uio(&tp->t_inq, tp, uio,
  245                     uio->uio_resid, 0);
  246                 if (error)
  247                         return (error);
  248                 if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
  249                         return (0);
  250 
  251                 /* Calculate how long we should wait. */
  252                 getmicrotime(&now);
  253                 if (timevalcmp(&now, &end, >))
  254                         return (0);
  255                 left = end;
  256                 timevalsub(&left, &now);
  257                 hz = tvtohz(&left);
  258 
  259                 /*
  260                  * We have to wait for more. If the timer expires, we
  261                  * should return a 0-byte read.
  262                  */
  263                 if (tp->t_flags & TF_ZOMBIE)
  264                         return (0);
  265                 else if (ioflag & IO_NDELAY)
  266                         return (EWOULDBLOCK);
  267 
  268                 error = tty_timedwait(tp, &tp->t_inwait, hz);
  269                 if (error)
  270                         return (error == EWOULDBLOCK ? 0 : error);
  271         }
  272 
  273         return (0);
  274 }
  275 
  276 static int
  277 ttydisc_read_raw_interbyte_timer(struct tty *tp, struct uio *uio, int ioflag)
  278 {
  279         size_t vmin = tp->t_termios.c_cc[VMIN];
  280         ssize_t oresid = uio->uio_resid;
  281         int error;
  282 
  283         MPASS(tp->t_termios.c_cc[VMIN] != 0);
  284         MPASS(tp->t_termios.c_cc[VTIME] != 0);
  285 
  286         /*
  287          * When using the interbyte timer, the timer should be started
  288          * after the first byte has been received. We just call into the
  289          * generic read timer code after we've received the first byte.
  290          */
  291 
  292         for (;;) {
  293                 error = tty_wait_background(tp, curthread, SIGTTIN);
  294                 if (error)
  295                         return (error);
  296 
  297                 error = ttyinq_read_uio(&tp->t_inq, tp, uio,
  298                     uio->uio_resid, 0);
  299                 if (error)
  300                         return (error);
  301                 if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
  302                         return (0);
  303 
  304                 /*
  305                  * Not enough data, but we did receive some, which means
  306                  * we'll now start using the interbyte timer.
  307                  */
  308                 if (oresid != uio->uio_resid)
  309                         break;
  310 
  311                 /* We have to wait for more. */
  312                 if (tp->t_flags & TF_ZOMBIE)
  313                         return (0);
  314                 else if (ioflag & IO_NDELAY)
  315                         return (EWOULDBLOCK);
  316 
  317                 error = tty_wait(tp, &tp->t_inwait);
  318                 if (error)
  319                         return (error);
  320         }
  321 
  322         return ttydisc_read_raw_read_timer(tp, uio, ioflag, oresid);
  323 }
  324 
  325 int
  326 ttydisc_read(struct tty *tp, struct uio *uio, int ioflag)
  327 {
  328         int error;
  329 
  330         tty_lock_assert(tp, MA_OWNED);
  331 
  332         if (uio->uio_resid == 0)
  333                 return (0);
  334 
  335         if (CMP_FLAG(l, ICANON))
  336                 error = ttydisc_read_canonical(tp, uio, ioflag);
  337         else if (tp->t_termios.c_cc[VTIME] == 0)
  338                 error = ttydisc_read_raw_no_timer(tp, uio, ioflag);
  339         else if (tp->t_termios.c_cc[VMIN] == 0)
  340                 error = ttydisc_read_raw_read_timer(tp, uio, ioflag,
  341                     uio->uio_resid);
  342         else
  343                 error = ttydisc_read_raw_interbyte_timer(tp, uio, ioflag);
  344 
  345         if (ttyinq_bytesleft(&tp->t_inq) >= tp->t_inlow ||
  346             ttyinq_bytescanonicalized(&tp->t_inq) == 0) {
  347                 /* Unset the input watermark when we've got enough space. */
  348                 tty_hiwat_in_unblock(tp);
  349         }
  350 
  351         return (error);
  352 }
  353 
  354 static __inline unsigned int
  355 ttydisc_findchar(const char *obstart, unsigned int oblen)
  356 {
  357         const char *c = obstart;
  358 
  359         while (oblen--) {
  360                 if (CTL_VALID(*c))
  361                         break;
  362                 c++;
  363         }
  364 
  365         return (c - obstart);
  366 }
  367 
  368 static int
  369 ttydisc_write_oproc(struct tty *tp, char c)
  370 {
  371         unsigned int scnt, error;
  372 
  373         MPASS(CMP_FLAG(o, OPOST));
  374         MPASS(CTL_VALID(c));
  375 
  376 #define PRINT_NORMAL() ttyoutq_write_nofrag(&tp->t_outq, &c, 1)
  377         switch (c) {
  378         case CEOF:
  379                 /* End-of-text dropping. */
  380                 if (CMP_FLAG(o, ONOEOT))
  381                         return (0);
  382                 return PRINT_NORMAL();
  383 
  384         case CERASE2:
  385                 /* Handle backspace to fix tab expansion. */
  386                 if (PRINT_NORMAL() != 0)
  387                         return (-1);
  388                 if (tp->t_column > 0)
  389                         tp->t_column--;
  390                 return (0);
  391 
  392         case CTAB:
  393                 /* Tab expansion. */
  394                 scnt = 8 - (tp->t_column & 7);
  395                 if (CMP_FLAG(o, TAB3)) {
  396                         error = ttyoutq_write_nofrag(&tp->t_outq,
  397                             "        ", scnt);
  398                 } else {
  399                         error = PRINT_NORMAL();
  400                 }
  401                 if (error)
  402                         return (-1);
  403 
  404                 tp->t_column += scnt;
  405                 MPASS((tp->t_column % 8) == 0);
  406                 return (0);
  407 
  408         case CNL:
  409                 /* Newline conversion. */
  410                 if (CMP_FLAG(o, ONLCR)) {
  411                         /* Convert \n to \r\n. */
  412                         error = ttyoutq_write_nofrag(&tp->t_outq, "\r\n", 2);
  413                 } else {
  414                         error = PRINT_NORMAL();
  415                 }
  416                 if (error)
  417                         return (-1);
  418 
  419                 if (CMP_FLAG(o, ONLCR|ONLRET)) {
  420                         tp->t_column = tp->t_writepos = 0;
  421                         ttyinq_reprintpos_set(&tp->t_inq);
  422                 }
  423                 return (0);
  424 
  425         case CCR:
  426                 /* Carriage return to newline conversion. */
  427                 if (CMP_FLAG(o, OCRNL))
  428                         c = CNL;
  429                 /* Omit carriage returns on column 0. */
  430                 if (CMP_FLAG(o, ONOCR) && tp->t_column == 0)
  431                         return (0);
  432                 if (PRINT_NORMAL() != 0)
  433                         return (-1);
  434 
  435                 tp->t_column = tp->t_writepos = 0;
  436                 ttyinq_reprintpos_set(&tp->t_inq);
  437                 return (0);
  438         }
  439 
  440         /*
  441          * Invisible control character. Print it, but don't
  442          * increase the column count.
  443          */
  444         return PRINT_NORMAL();
  445 #undef PRINT_NORMAL
  446 }
  447 
  448 /*
  449  * Just like the old TTY implementation, we need to copy data in chunks
  450  * into a temporary buffer. One of the reasons why we need to do this,
  451  * is because output processing (only TAB3 though) may allow the buffer
  452  * to grow eight times.
  453  */
  454 int
  455 ttydisc_write(struct tty *tp, struct uio *uio, int ioflag)
  456 {
  457         char ob[TTY_STACKBUF];
  458         char *obstart;
  459         int error = 0;
  460         unsigned int oblen = 0;
  461 
  462         tty_lock_assert(tp, MA_OWNED);
  463 
  464         if (tp->t_flags & TF_ZOMBIE)
  465                 return (EIO);
  466 
  467         /*
  468          * We don't need to check whether the process is the foreground
  469          * process group or if we have a carrier. This is already done
  470          * in ttydev_write().
  471          */
  472 
  473         while (uio->uio_resid > 0) {
  474                 unsigned int nlen;
  475 
  476                 MPASS(oblen == 0);
  477 
  478                 /* Step 1: read data. */
  479                 obstart = ob;
  480                 nlen = MIN(uio->uio_resid, sizeof ob);
  481                 tty_unlock(tp);
  482                 error = uiomove(ob, nlen, uio);
  483                 tty_lock(tp);
  484                 if (error != 0)
  485                         break;
  486                 oblen = nlen;
  487 
  488                 if (tty_gone(tp)) {
  489                         error = ENXIO;
  490                         break;
  491                 }
  492 
  493                 MPASS(oblen > 0);
  494 
  495                 /* Step 2: process data. */
  496                 do {
  497                         unsigned int plen, wlen;
  498 
  499                         /* Search for special characters for post processing. */
  500                         if (CMP_FLAG(o, OPOST)) {
  501                                 plen = ttydisc_findchar(obstart, oblen);
  502                         } else {
  503                                 plen = oblen;
  504                         }
  505 
  506                         if (plen == 0) {
  507                                 /*
  508                                  * We're going to process a character
  509                                  * that needs processing
  510                                  */
  511                                 if (ttydisc_write_oproc(tp, *obstart) == 0) {
  512                                         obstart++;
  513                                         oblen--;
  514 
  515                                         tp->t_writepos = tp->t_column;
  516                                         ttyinq_reprintpos_set(&tp->t_inq);
  517                                         continue;
  518                                 }
  519                         } else {
  520                                 /* We're going to write regular data. */
  521                                 wlen = ttyoutq_write(&tp->t_outq, obstart, plen);
  522                                 obstart += wlen;
  523                                 oblen -= wlen;
  524                                 tp->t_column += wlen;
  525 
  526                                 tp->t_writepos = tp->t_column;
  527                                 ttyinq_reprintpos_set(&tp->t_inq);
  528 
  529                                 if (wlen == plen)
  530                                         continue;
  531                         }
  532 
  533                         /* Watermark reached. Try to sleep. */
  534                         tp->t_flags |= TF_HIWAT_OUT;
  535 
  536                         if (ioflag & IO_NDELAY) {
  537                                 error = EWOULDBLOCK;
  538                                 goto done;
  539                         }
  540 
  541                         /*
  542                          * The driver may write back the data
  543                          * synchronously. Be sure to check the high
  544                          * water mark before going to sleep.
  545                          */
  546                         ttydevsw_outwakeup(tp);
  547                         if ((tp->t_flags & TF_HIWAT_OUT) == 0)
  548                                 continue;
  549 
  550                         error = tty_wait(tp, &tp->t_outwait);
  551                         if (error)
  552                                 goto done;
  553 
  554                         if (tp->t_flags & TF_ZOMBIE) {
  555                                 error = EIO;
  556                                 goto done;
  557                         }
  558                 } while (oblen > 0);
  559         }
  560 
  561 done:
  562         if (!tty_gone(tp))
  563                 ttydevsw_outwakeup(tp);
  564 
  565         /*
  566          * Add the amount of bytes that we didn't process back to the
  567          * uio counters. We need to do this to make sure write() doesn't
  568          * count the bytes we didn't store in the queue.
  569          */
  570         uio->uio_resid += oblen;
  571         return (error);
  572 }
  573 
  574 void
  575 ttydisc_optimize(struct tty *tp)
  576 {
  577         tty_lock_assert(tp, MA_OWNED);
  578 
  579         if (ttyhook_hashook(tp, rint_bypass)) {
  580                 tp->t_flags |= TF_BYPASS;
  581         } else if (ttyhook_hashook(tp, rint)) {
  582                 tp->t_flags &= ~TF_BYPASS;
  583         } else if (!CMP_FLAG(i, ICRNL|IGNCR|IMAXBEL|INLCR|ISTRIP|IXON) &&
  584             (!CMP_FLAG(i, BRKINT) || CMP_FLAG(i, IGNBRK)) &&
  585             (!CMP_FLAG(i, PARMRK) ||
  586                 CMP_FLAG(i, IGNPAR|IGNBRK) == (IGNPAR|IGNBRK)) &&
  587             !CMP_FLAG(l, ECHO|ICANON|IEXTEN|ISIG|PENDIN)) {
  588                 tp->t_flags |= TF_BYPASS;
  589         } else {
  590                 tp->t_flags &= ~TF_BYPASS;
  591         }
  592 }
  593 
  594 void
  595 ttydisc_modem(struct tty *tp, int open)
  596 {
  597 
  598         tty_lock_assert(tp, MA_OWNED);
  599 
  600         if (open)
  601                 cv_broadcast(&tp->t_dcdwait);
  602 
  603         /*
  604          * Ignore modem status lines when CLOCAL is turned on, but don't
  605          * enter the zombie state when the TTY isn't opened, because
  606          * that would cause the TTY to be in zombie state after being
  607          * opened.
  608          */
  609         if (!tty_opened(tp) || CMP_FLAG(c, CLOCAL))
  610                 return;
  611 
  612         if (open == 0) {
  613                 /*
  614                  * Lost carrier.
  615                  */
  616                 tp->t_flags |= TF_ZOMBIE;
  617 
  618                 tty_signal_sessleader(tp, SIGHUP);
  619                 tty_flush(tp, FREAD|FWRITE);
  620         } else {
  621                 /*
  622                  * Carrier is back again.
  623                  */
  624 
  625                 /* XXX: what should we do here? */
  626         }
  627 }
  628 
  629 static int
  630 ttydisc_echo_force(struct tty *tp, char c, int quote)
  631 {
  632 
  633         if (CMP_FLAG(o, OPOST) && CTL_ECHO(c, quote)) {
  634                 /*
  635                  * Only perform postprocessing when OPOST is turned on
  636                  * and the character is an unquoted BS/TB/NL/CR.
  637                  */
  638                 return ttydisc_write_oproc(tp, c);
  639         } else if (CMP_FLAG(l, ECHOCTL) && CTL_PRINT(c, quote)) {
  640                 /*
  641                  * Only use ^X notation when ECHOCTL is turned on and
  642                  * we've got an quoted control character.
  643                  *
  644                  * Print backspaces when echoing an end-of-file.
  645                  */
  646                 char ob[4] = "^?\b\b";
  647 
  648                 /* Print ^X notation. */
  649                 if (c != 0x7f)
  650                         ob[1] = c + 'A' - 1;
  651 
  652                 if (!quote && CMP_CC(VEOF, c)) {
  653                         return ttyoutq_write_nofrag(&tp->t_outq, ob, 4);
  654                 } else {
  655                         tp->t_column += 2;
  656                         return ttyoutq_write_nofrag(&tp->t_outq, ob, 2);
  657                 }
  658         } else {
  659                 /* Can just be printed. */
  660                 tp->t_column++;
  661                 return ttyoutq_write_nofrag(&tp->t_outq, &c, 1);
  662         }
  663 }
  664 
  665 static int
  666 ttydisc_echo(struct tty *tp, char c, int quote)
  667 {
  668 
  669         /*
  670          * Only echo characters when ECHO is turned on, or ECHONL when
  671          * the character is an unquoted newline.
  672          */
  673         if (!CMP_FLAG(l, ECHO) &&
  674             (!CMP_FLAG(l, ECHONL) || c != CNL || quote))
  675                 return (0);
  676 
  677         return ttydisc_echo_force(tp, c, quote);
  678 }
  679 
  680 
  681 static void
  682 ttydisc_reprint_char(void *d, char c, int quote)
  683 {
  684         struct tty *tp = d;
  685 
  686         ttydisc_echo(tp, c, quote);
  687 }
  688 
  689 static void
  690 ttydisc_reprint(struct tty *tp)
  691 {
  692         cc_t c;
  693 
  694         /* Print  ^R\n, followed by the line. */
  695         c = tp->t_termios.c_cc[VREPRINT];
  696         if (c != _POSIX_VDISABLE)
  697                 ttydisc_echo(tp, c, 0);
  698         ttydisc_echo(tp, CNL, 0);
  699         ttyinq_reprintpos_reset(&tp->t_inq);
  700 
  701         ttyinq_line_iterate_from_linestart(&tp->t_inq, ttydisc_reprint_char, tp);
  702 }
  703 
  704 struct ttydisc_recalc_length {
  705         struct tty *tp;
  706         unsigned int curlen;
  707 };
  708 
  709 static void
  710 ttydisc_recalc_charlength(void *d, char c, int quote)
  711 {
  712         struct ttydisc_recalc_length *data = d;
  713         struct tty *tp = data->tp;
  714 
  715         if (CTL_PRINT(c, quote)) {
  716                 if (CMP_FLAG(l, ECHOCTL))
  717                         data->curlen += 2;
  718         } else if (c == CTAB) {
  719                 data->curlen += 8 - (data->curlen & 7);
  720         } else {
  721                 data->curlen++;
  722         }
  723 }
  724 
  725 static unsigned int
  726 ttydisc_recalc_linelength(struct tty *tp)
  727 {
  728         struct ttydisc_recalc_length data = { tp, tp->t_writepos };
  729 
  730         ttyinq_line_iterate_from_reprintpos(&tp->t_inq,
  731             ttydisc_recalc_charlength, &data);
  732         return (data.curlen);
  733 }
  734 
  735 static int
  736 ttydisc_rubchar(struct tty *tp)
  737 {
  738         char c;
  739         int quote;
  740         unsigned int prevpos, tablen;
  741 
  742         if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
  743                 return (-1);
  744         ttyinq_unputchar(&tp->t_inq);
  745 
  746         if (CMP_FLAG(l, ECHO)) {
  747                 /*
  748                  * Remove the character from the screen. This is even
  749                  * safe for characters that span multiple characters
  750                  * (tabs, quoted, etc).
  751                  */
  752                 if (tp->t_writepos >= tp->t_column) {
  753                         /* Retype the sentence. */
  754                         ttydisc_reprint(tp);
  755                 } else if (CMP_FLAG(l, ECHOE)) {
  756                         if (CTL_PRINT(c, quote)) {
  757                                 /* Remove ^X formatted chars. */
  758                                 if (CMP_FLAG(l, ECHOCTL)) {
  759                                         tp->t_column -= 2;
  760                                         ttyoutq_write_nofrag(&tp->t_outq,
  761                                             "\b\b  \b\b", 6);
  762                                 }
  763                         } else if (c == ' ') {
  764                                 /* Space character needs no rubbing. */
  765                                 tp->t_column -= 1;
  766                                 ttyoutq_write_nofrag(&tp->t_outq, "\b", 1);
  767                         } else if (c == CTAB) {
  768                                 /*
  769                                  * Making backspace work with tabs is
  770                                  * quite hard. Recalculate the length of
  771                                  * this character and remove it.
  772                                  *
  773                                  * Because terminal settings could be
  774                                  * changed while the line is being
  775                                  * inserted, the calculations don't have
  776                                  * to be correct. Make sure we keep the
  777                                  * tab length within proper bounds.
  778                                  */
  779                                 prevpos = ttydisc_recalc_linelength(tp);
  780                                 if (prevpos >= tp->t_column)
  781                                         tablen = 1;
  782                                 else
  783                                         tablen = tp->t_column - prevpos;
  784                                 if (tablen > 8)
  785                                         tablen = 8;
  786 
  787                                 tp->t_column = prevpos;
  788                                 ttyoutq_write_nofrag(&tp->t_outq,
  789                                     "\b\b\b\b\b\b\b\b", tablen);
  790                                 return (0);
  791                         } else {
  792                                 /*
  793                                  * Remove a regular character by
  794                                  * punching a space over it.
  795                                  */
  796                                 tp->t_column -= 1;
  797                                 ttyoutq_write_nofrag(&tp->t_outq, "\b \b", 3);
  798                         }
  799                 } else {
  800                         /* Don't print spaces. */
  801                         ttydisc_echo(tp, tp->t_termios.c_cc[VERASE], 0);
  802                 }
  803         }
  804 
  805         return (0);
  806 }
  807 
  808 static void
  809 ttydisc_rubword(struct tty *tp)
  810 {
  811         char c;
  812         int quote, alnum;
  813 
  814         /* Strip whitespace first. */
  815         for (;;) {
  816                 if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
  817                         return;
  818                 if (!CTL_WHITE(c))
  819                         break;
  820                 ttydisc_rubchar(tp);
  821         }
  822 
  823         /*
  824          * Record whether the last character from the previous iteration
  825          * was alphanumeric or not. We need this to implement ALTWERASE.
  826          */
  827         alnum = CTL_ALNUM(c);
  828         for (;;) {
  829                 ttydisc_rubchar(tp);
  830 
  831                 if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
  832                         return;
  833                 if (CTL_WHITE(c))
  834                         return;
  835                 if (CMP_FLAG(l, ALTWERASE) && CTL_ALNUM(c) != alnum)
  836                         return;
  837         }
  838 }
  839 
  840 int
  841 ttydisc_rint(struct tty *tp, char c, int flags)
  842 {
  843         int signal, quote = 0;
  844         char ob[3] = { 0xff, 0x00 };
  845         size_t ol;
  846 
  847         tty_lock_assert(tp, MA_OWNED);
  848 
  849         atomic_add_long(&tty_nin, 1);
  850 
  851         if (ttyhook_hashook(tp, rint))
  852                 return ttyhook_rint(tp, c, flags);
  853 
  854         if (tp->t_flags & TF_BYPASS)
  855                 goto processed;
  856 
  857         if (flags) {
  858                 if (flags & TRE_BREAK) {
  859                         if (CMP_FLAG(i, IGNBRK)) {
  860                                 /* Ignore break characters. */
  861                                 return (0);
  862                         } else if (CMP_FLAG(i, BRKINT)) {
  863                                 /* Generate SIGINT on break. */
  864                                 tty_flush(tp, FREAD|FWRITE);
  865                                 tty_signal_pgrp(tp, SIGINT);
  866                                 return (0);
  867                         } else {
  868                                 /* Just print it. */
  869                                 goto parmrk;
  870                         }
  871                 } else if (flags & TRE_FRAMING ||
  872                     (flags & TRE_PARITY && CMP_FLAG(i, INPCK))) {
  873                         if (CMP_FLAG(i, IGNPAR)) {
  874                                 /* Ignore bad characters. */
  875                                 return (0);
  876                         } else {
  877                                 /* Just print it. */
  878                                 goto parmrk;
  879                         }
  880                 }
  881         }
  882 
  883         /* Allow any character to perform a wakeup. */
  884         if (CMP_FLAG(i, IXANY))
  885                 tp->t_flags &= ~TF_STOPPED;
  886 
  887         /* Remove the top bit. */
  888         if (CMP_FLAG(i, ISTRIP))
  889                 c &= ~0x80;
  890 
  891         /* Skip input processing when we want to print it literally. */
  892         if (tp->t_flags & TF_LITERAL) {
  893                 tp->t_flags &= ~TF_LITERAL;
  894                 quote = 1;
  895                 goto processed;
  896         }
  897 
  898         /* Special control characters that are implementation dependent. */
  899         if (CMP_FLAG(l, IEXTEN)) {
  900                 /* Accept the next character as literal. */
  901                 if (CMP_CC(VLNEXT, c)) {
  902                         if (CMP_FLAG(l, ECHO)) {
  903                                 if (CMP_FLAG(l, ECHOE))
  904                                         ttyoutq_write_nofrag(&tp->t_outq, "^\b", 2);
  905                                 else
  906                                         ttydisc_echo(tp, c, 0);
  907                         }
  908                         tp->t_flags |= TF_LITERAL;
  909                         return (0);
  910                 }
  911         }
  912 
  913         /*
  914          * Handle signal processing.
  915          */
  916         if (CMP_FLAG(l, ISIG)) {
  917                 if (CMP_FLAG(l, ICANON|IEXTEN) == (ICANON|IEXTEN)) {
  918                         if (CMP_CC(VSTATUS, c)) {
  919                                 tty_signal_pgrp(tp, SIGINFO);
  920                                 return (0);
  921                         }
  922                 }
  923 
  924                 /*
  925                  * When compared to the old implementation, this
  926                  * implementation also flushes the output queue. POSIX
  927                  * is really brief about this, but does makes us assume
  928                  * we have to do so.
  929                  */
  930                 signal = 0;
  931                 if (CMP_CC(VINTR, c)) {
  932                         signal = SIGINT;
  933                 } else if (CMP_CC(VQUIT, c)) {
  934                         signal = SIGQUIT;
  935                 } else if (CMP_CC(VSUSP, c)) {
  936                         signal = SIGTSTP;
  937                 }
  938 
  939                 if (signal != 0) {
  940                         /*
  941                          * Echo the character before signalling the
  942                          * processes.
  943                          */
  944                         if (!CMP_FLAG(l, NOFLSH))
  945                                 tty_flush(tp, FREAD|FWRITE);
  946                         ttydisc_echo(tp, c, 0);
  947                         tty_signal_pgrp(tp, signal);
  948                         return (0);
  949                 }
  950         }
  951 
  952         /*
  953          * Handle start/stop characters.
  954          */
  955         if (CMP_FLAG(i, IXON)) {
  956                 if (CMP_CC(VSTOP, c)) {
  957                         /* Stop it if we aren't stopped yet. */
  958                         if ((tp->t_flags & TF_STOPPED) == 0) {
  959                                 tp->t_flags |= TF_STOPPED;
  960                                 return (0);
  961                         }
  962                         /*
  963                          * Fallthrough:
  964                          * When VSTART == VSTOP, we should make this key
  965                          * toggle it.
  966                          */
  967                         if (!CMP_CC(VSTART, c))
  968                                 return (0);
  969                 }
  970                 if (CMP_CC(VSTART, c)) {
  971                         tp->t_flags &= ~TF_STOPPED;
  972                         return (0);
  973                 }
  974         }
  975 
  976         /* Conversion of CR and NL. */
  977         switch (c) {
  978         case CCR:
  979                 if (CMP_FLAG(i, IGNCR))
  980                         return (0);
  981                 if (CMP_FLAG(i, ICRNL))
  982                         c = CNL;
  983                 break;
  984         case CNL:
  985                 if (CMP_FLAG(i, INLCR))
  986                         c = CCR;
  987                 break;
  988         }
  989 
  990         /* Canonical line editing. */
  991         if (CMP_FLAG(l, ICANON)) {
  992                 if (CMP_CC(VERASE, c) || CMP_CC(VERASE2, c)) {
  993                         ttydisc_rubchar(tp);
  994                         return (0);
  995                 } else if (CMP_CC(VKILL, c)) {
  996                         while (ttydisc_rubchar(tp) == 0);
  997                         return (0);
  998                 } else if (CMP_FLAG(l, IEXTEN)) {
  999                         if (CMP_CC(VWERASE, c)) {
 1000                                 ttydisc_rubword(tp);
 1001                                 return (0);
 1002                         } else if (CMP_CC(VREPRINT, c)) {
 1003                                 ttydisc_reprint(tp);
 1004                                 return (0);
 1005                         }
 1006                 }
 1007         }
 1008 
 1009 processed:
 1010         if (CMP_FLAG(i, PARMRK) && (unsigned char)c == 0xff) {
 1011                 /* Print 0xff 0xff. */
 1012                 ob[1] = 0xff;
 1013                 ol = 2;
 1014                 quote = 1;
 1015         } else {
 1016                 ob[0] = c;
 1017                 ol = 1;
 1018         }
 1019 
 1020         goto print;
 1021 
 1022 parmrk:
 1023         if (CMP_FLAG(i, PARMRK)) {
 1024                 /* Prepend 0xff 0x00 0x.. */
 1025                 ob[2] = c;
 1026                 ol = 3;
 1027                 quote = 1;
 1028         } else {
 1029                 ob[0] = c;
 1030                 ol = 1;
 1031         }
 1032 
 1033 print:
 1034         /* See if we can store this on the input queue. */
 1035         if (ttyinq_write_nofrag(&tp->t_inq, ob, ol, quote) != 0) {
 1036                 if (CMP_FLAG(i, IMAXBEL))
 1037                         ttyoutq_write_nofrag(&tp->t_outq, "\a", 1);
 1038 
 1039                 /*
 1040                  * Prevent a deadlock here. It may be possible that a
 1041                  * user has entered so much data, there is no data
 1042                  * available to read(), but the buffers are full anyway.
 1043                  *
 1044                  * Only enter the high watermark if the device driver
 1045                  * can actually transmit something.
 1046                  */
 1047                 if (ttyinq_bytescanonicalized(&tp->t_inq) == 0)
 1048                         return (0);
 1049 
 1050                 tty_hiwat_in_block(tp);
 1051                 return (-1);
 1052         }
 1053 
 1054         /*
 1055          * In raw mode, we canonicalize after receiving a single
 1056          * character. Otherwise, we canonicalize when we receive a
 1057          * newline, VEOL or VEOF, but only when it isn't quoted.
 1058          */
 1059         if (!CMP_FLAG(l, ICANON) ||
 1060             (!quote && (c == CNL || CMP_CC(VEOL, c) || CMP_CC(VEOF, c)))) {
 1061                 ttyinq_canonicalize(&tp->t_inq);
 1062         }
 1063 
 1064         ttydisc_echo(tp, c, quote);
 1065 
 1066         return (0);
 1067 }
 1068 
 1069 size_t
 1070 ttydisc_rint_simple(struct tty *tp, const void *buf, size_t len)
 1071 {
 1072         const char *cbuf;
 1073 
 1074         if (ttydisc_can_bypass(tp))
 1075                 return (ttydisc_rint_bypass(tp, buf, len));
 1076 
 1077         for (cbuf = buf; len-- > 0; cbuf++) {
 1078                 if (ttydisc_rint(tp, *cbuf, 0) != 0)
 1079                         break;
 1080         }
 1081 
 1082         return (cbuf - (const char *)buf);
 1083 }
 1084 
 1085 size_t
 1086 ttydisc_rint_bypass(struct tty *tp, const void *buf, size_t len)
 1087 {
 1088         size_t ret;
 1089 
 1090         tty_lock_assert(tp, MA_OWNED);
 1091 
 1092         MPASS(tp->t_flags & TF_BYPASS);
 1093 
 1094         atomic_add_long(&tty_nin, len);
 1095 
 1096         if (ttyhook_hashook(tp, rint_bypass))
 1097                 return ttyhook_rint_bypass(tp, buf, len);
 1098 
 1099         ret = ttyinq_write(&tp->t_inq, buf, len, 0);
 1100         ttyinq_canonicalize(&tp->t_inq);
 1101         if (ret < len)
 1102                 tty_hiwat_in_block(tp);
 1103 
 1104         return (ret);
 1105 }
 1106 
 1107 void
 1108 ttydisc_rint_done(struct tty *tp)
 1109 {
 1110 
 1111         tty_lock_assert(tp, MA_OWNED);
 1112 
 1113         if (ttyhook_hashook(tp, rint_done))
 1114                 ttyhook_rint_done(tp);
 1115 
 1116         /* Wake up readers. */
 1117         tty_wakeup(tp, FREAD);
 1118         /* Wake up driver for echo. */
 1119         ttydevsw_outwakeup(tp);
 1120 }
 1121 
 1122 size_t
 1123 ttydisc_rint_poll(struct tty *tp)
 1124 {
 1125         size_t l;
 1126 
 1127         tty_lock_assert(tp, MA_OWNED);
 1128 
 1129         if (ttyhook_hashook(tp, rint_poll))
 1130                 return ttyhook_rint_poll(tp);
 1131 
 1132         /*
 1133          * XXX: Still allow character input when there's no space in the
 1134          * buffers, but we haven't entered the high watermark. This is
 1135          * to allow backspace characters to be inserted when in
 1136          * canonical mode.
 1137          */
 1138         l = ttyinq_bytesleft(&tp->t_inq);
 1139         if (l == 0 && (tp->t_flags & TF_HIWAT_IN) == 0)
 1140                 return (1);
 1141 
 1142         return (l);
 1143 }
 1144 
 1145 static void
 1146 ttydisc_wakeup_watermark(struct tty *tp)
 1147 {
 1148         size_t c;
 1149 
 1150         c = ttyoutq_bytesleft(&tp->t_outq);
 1151         if (tp->t_flags & TF_HIWAT_OUT) {
 1152                 /* Only allow us to run when we're below the watermark. */
 1153                 if (c < tp->t_outlow)
 1154                         return;
 1155 
 1156                 /* Reset the watermark. */
 1157                 tp->t_flags &= ~TF_HIWAT_OUT;
 1158         } else {
 1159                 /* Only run when we have data at all. */
 1160                 if (c == 0)
 1161                         return;
 1162         }
 1163         tty_wakeup(tp, FWRITE);
 1164 }
 1165 
 1166 size_t
 1167 ttydisc_getc(struct tty *tp, void *buf, size_t len)
 1168 {
 1169 
 1170         tty_lock_assert(tp, MA_OWNED);
 1171 
 1172         if (tp->t_flags & TF_STOPPED)
 1173                 return (0);
 1174 
 1175         if (ttyhook_hashook(tp, getc_inject))
 1176                 return ttyhook_getc_inject(tp, buf, len);
 1177 
 1178         len = ttyoutq_read(&tp->t_outq, buf, len);
 1179 
 1180         if (ttyhook_hashook(tp, getc_capture))
 1181                 ttyhook_getc_capture(tp, buf, len);
 1182 
 1183         ttydisc_wakeup_watermark(tp);
 1184         atomic_add_long(&tty_nout, len);
 1185 
 1186         return (len);
 1187 }
 1188 
 1189 int
 1190 ttydisc_getc_uio(struct tty *tp, struct uio *uio)
 1191 {
 1192         int error = 0;
 1193         ssize_t obytes = uio->uio_resid;
 1194         size_t len;
 1195         char buf[TTY_STACKBUF];
 1196 
 1197         tty_lock_assert(tp, MA_OWNED);
 1198 
 1199         if (tp->t_flags & TF_STOPPED)
 1200                 return (0);
 1201 
 1202         /*
 1203          * When a TTY hook is attached, we cannot perform unbuffered
 1204          * copying to userspace. Just call ttydisc_getc() and
 1205          * temporarily store data in a shadow buffer.
 1206          */
 1207         if (ttyhook_hashook(tp, getc_capture) ||
 1208             ttyhook_hashook(tp, getc_inject)) {
 1209                 while (uio->uio_resid > 0) {
 1210                         /* Read to shadow buffer. */
 1211                         len = ttydisc_getc(tp, buf,
 1212                             MIN(uio->uio_resid, sizeof buf));
 1213                         if (len == 0)
 1214                                 break;
 1215 
 1216                         /* Copy to userspace. */
 1217                         tty_unlock(tp);
 1218                         error = uiomove(buf, len, uio);
 1219                         tty_lock(tp);
 1220 
 1221                         if (error != 0)
 1222                                 break;
 1223                 }
 1224         } else {
 1225                 error = ttyoutq_read_uio(&tp->t_outq, tp, uio);
 1226 
 1227                 ttydisc_wakeup_watermark(tp);
 1228                 atomic_add_long(&tty_nout, obytes - uio->uio_resid);
 1229         }
 1230 
 1231         return (error);
 1232 }
 1233 
 1234 size_t
 1235 ttydisc_getc_poll(struct tty *tp)
 1236 {
 1237 
 1238         tty_lock_assert(tp, MA_OWNED);
 1239 
 1240         if (tp->t_flags & TF_STOPPED)
 1241                 return (0);
 1242 
 1243         if (ttyhook_hashook(tp, getc_poll))
 1244                 return ttyhook_getc_poll(tp);
 1245 
 1246         return ttyoutq_bytesused(&tp->t_outq);
 1247 }
 1248 
 1249 /*
 1250  * XXX: not really related to the TTYDISC, but we'd better put
 1251  * tty_putchar() here, because we need to perform proper output
 1252  * processing.
 1253  */
 1254 
 1255 int
 1256 tty_putchar(struct tty *tp, char c)
 1257 {
 1258         tty_lock_assert(tp, MA_OWNED);
 1259 
 1260         if (tty_gone(tp))
 1261                 return (-1);
 1262 
 1263         ttydisc_echo_force(tp, c, 0);
 1264         tp->t_writepos = tp->t_column;
 1265         ttyinq_reprintpos_set(&tp->t_inq);
 1266 
 1267         ttydevsw_outwakeup(tp);
 1268         return (0);
 1269 }

Cache object: 01df14ac31dcc791070d67dd645cac72


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.