git.distorted.org.uk Git - u/mdw/putty/blob - ldisc.c

   1 /*
   2  * ldisc.c: PuTTY line discipline. Sits between the input coming
   3  * from keypresses in the window, and the output channel leading to
   4  * the back end. Implements echo and/or local line editing,
   5  * depending on what's currently configured.
   6  */
   7
   8 #include <stdio.h>
   9 #include <ctype.h>
  10
  11 #include "putty.h"
  12 #include "terminal.h"
  13 #include "ldisc.h"
  14
  15 #define ECHOING (ldisc->cfg->localecho == LD_YES || \
  16                  (ldisc->cfg->localecho == LD_BACKEND && \
  17                       (ldisc->back->ldisc(ldisc->backhandle, LD_ECHO) || \
  18                            term_ldisc(ldisc->term, LD_ECHO))))
  19 #define EDITING (ldisc->cfg->localedit == LD_YES || \
  20                  (ldisc->cfg->localedit == LD_BACKEND && \
  21                       (ldisc->back->ldisc(ldisc->backhandle, LD_EDIT) || \
  22                            term_ldisc(ldisc->term, LD_EDIT))))
  23
  24 static void c_write(Ldisc ldisc, char *buf, int len)
  25 {
  26     from_backend(ldisc->term, 0, buf, len);
  27 }
  28
  29 static int plen(Ldisc ldisc, unsigned char c)
  30 {
  31     if ((c >= 32 && c <= 126) || (c >= 160 && !in_utf(ldisc->term)))
  32         return 1;
  33     else if (c < 128)
  34         return 2;                      /* ^x for some x */
  35     else
  36         return 4;                      /* <XY> for hex XY */
  37 }
  38
  39 static void pwrite(Ldisc ldisc, unsigned char c)
  40 {
  41     if ((c >= 32 && c <= 126) || (c >= 160 && !in_utf(ldisc->term))) {
  42         c_write(ldisc, (char *)&c, 1);
  43     } else if (c < 128) {
  44         char cc[2];
  45         cc[1] = (c == 127 ? '?' : c + 0x40);
  46         cc[0] = '^';
  47         c_write(ldisc, cc, 2);
  48     } else {
  49         char cc[5];
  50         sprintf(cc, "<%02X>", c);
  51         c_write(ldisc, cc, 4);
  52     }
  53 }
  54
  55 static void bsb(Ldisc ldisc, int n)
  56 {
  57     while (n--)
  58         c_write(ldisc, "\010 \010", 3);
  59 }
  60
  61 #define CTRL(x) (x^'@')
  62 #define KCTRL(x) ((x^'@') | 0x100)
  63
  64 void *ldisc_create(Config *mycfg, Terminal *term,
  65                    Backend *back, void *backhandle,
  66                    void *frontend)
  67 {
  68     Ldisc ldisc = smalloc(sizeof(*ldisc));
  69
  70     ldisc->buf = NULL;
  71     ldisc->buflen = 0;
  72     ldisc->bufsiz = 0;
  73     ldisc->quotenext = 0;
  74
  75     ldisc->cfg = mycfg;
  76     ldisc->back = back;
  77     ldisc->backhandle = backhandle;
  78     ldisc->term = term;
  79     ldisc->frontend = frontend;
  80
  81     /* Link ourselves into the backend and the terminal */
  82     if (term)
  83         term->ldisc = ldisc;
  84     if (back)
  85         back->provide_ldisc(backhandle, ldisc);
  86
  87     return ldisc;
  88 }
  89
  90 void ldisc_free(void *handle)
  91 {
  92     Ldisc ldisc = (Ldisc) handle;
  93
  94     if (ldisc->term)
  95         ldisc->term->ldisc = NULL;
  96     if (ldisc->back)
  97         ldisc->back->provide_ldisc(ldisc->backhandle, NULL);
  98     if (ldisc->buf)
  99         sfree(ldisc->buf);
 100     sfree(ldisc);
 101 }
 102
 103 void ldisc_send(void *handle, char *buf, int len, int interactive)
 104 {
 105     Ldisc ldisc = (Ldisc) handle;
 106     int keyflag = 0;
 107     /*
 108      * Called with len=0 when the options change. We must inform
 109      * the front end in case it needs to know.
 110      */
 111     if (len == 0) {
 112         ldisc_update(ldisc->frontend, ECHOING, EDITING);
 113         return;
 114     }
 115     /*
 116      * Notify the front end that something was pressed, in case
 117      * it's depending on finding out (e.g. keypress termination for
 118      * Close On Exit).
 119      */
 120     frontend_keypress(ldisc->frontend);
 121
 122     /*
 123      * Less than zero means null terminated special string.
 124      */
 125     if (len < 0) {
 126         len = strlen(buf);
 127         keyflag = KCTRL('@');
 128     }
 129     /*
 130      * Either perform local editing, or just send characters.
 131      */
 132     if (EDITING) {
 133         while (len--) {
 134             int c;
 135             c = *buf++ + keyflag;
 136             if (!interactive && c == '\r')
 137                 c += KCTRL('@');
 138             switch (ldisc->quotenext ? ' ' : c) {
 139                 /*
 140                  * ^h/^?: delete one char and output one BSB
 141                  * ^w: delete, and output BSBs, to return to last
 142                  * space/nonspace boundary
 143                  * ^u: delete, and output BSBs, to return to BOL
 144                  * ^c: Do a ^u then send a telnet IP
 145                  * ^z: Do a ^u then send a telnet SUSP
 146                  * ^\: Do a ^u then send a telnet ABORT
 147                  * ^r: echo "^R\n" and redraw line
 148                  * ^v: quote next char
 149                  * ^d: if at BOL, end of file and close connection,
 150                  * else send line and reset to BOL
 151                  * ^m: send line-plus-\r\n and reset to BOL
 152                  */
 153               case KCTRL('H'):
 154               case KCTRL('?'):         /* backspace/delete */
 155                 if (ldisc->buflen > 0) {
 156                     if (ECHOING)
 157                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 158                     ldisc->buflen--;
 159                 }
 160                 break;
 161               case CTRL('W'):          /* delete word */
 162                 while (ldisc->buflen > 0) {
 163                     if (ECHOING)
 164                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 165                     ldisc->buflen--;
 166                     if (ldisc->buflen > 0 &&
 167                         isspace(ldisc->buf[ldisc->buflen - 1]) &&
 168                         !isspace(ldisc->buf[ldisc->buflen]))
 169                         break;
 170                 }
 171                 break;
 172               case CTRL('U'):          /* delete line */
 173               case CTRL('C'):          /* Send IP */
 174               case CTRL('\\'):         /* Quit */
 175               case CTRL('Z'):          /* Suspend */
 176                 while (ldisc->buflen > 0) {
 177                     if (ECHOING)
 178                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 179                     ldisc->buflen--;
 180                 }
 181                 ldisc->back->special(ldisc->backhandle, TS_EL);
 182                 /*
 183                  * We don't send IP, SUSP or ABORT if the user has
 184                  * configured telnet specials off! This breaks
 185                  * talkers otherwise.
 186                  */
 187                 if (!ldisc->cfg->telnet_keyboard)
 188                     goto default_case;
 189                 if (c == CTRL('C'))
 190                     ldisc->back->special(ldisc->backhandle, TS_IP);
 191                 if (c == CTRL('Z'))
 192                     ldisc->back->special(ldisc->backhandle, TS_SUSP);
 193                 if (c == CTRL('\\'))
 194                     ldisc->back->special(ldisc->backhandle, TS_ABORT);
 195                 break;
 196               case CTRL('R'):          /* redraw line */
 197                 if (ECHOING) {
 198                     int i;
 199                     c_write(ldisc, "^R\r\n", 4);
 200                     for (i = 0; i < ldisc->buflen; i++)
 201                         pwrite(ldisc, ldisc->buf[i]);
 202                 }
 203                 break;
 204               case CTRL('V'):          /* quote next char */
 205                 ldisc->quotenext = TRUE;
 206                 break;
 207               case CTRL('D'):          /* logout or send */
 208                 if (ldisc->buflen == 0) {
 209                     ldisc->back->special(ldisc->backhandle, TS_EOF);
 210                 } else {
 211                     ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 212                     ldisc->buflen = 0;
 213                 }
 214                 break;
 215                 /*
 216                  * This particularly hideous bit of code from RDB
 217                  * allows ordinary ^M^J to do the same thing as
 218                  * magic-^M when in Raw protocol. The line `case
 219                  * KCTRL('M'):' is _inside_ the if block. Thus:
 220                  *
 221                  *  - receiving regular ^M goes straight to the
 222                  *    default clause and inserts as a literal ^M.
 223                  *  - receiving regular ^J _not_ directly after a
 224                  *    literal ^M (or not in Raw protocol) fails the
 225                  *    if condition, leaps to the bottom of the if,
 226                  *    and falls through into the default clause
 227                  *    again.
 228                  *  - receiving regular ^J just after a literal ^M
 229                  *    in Raw protocol passes the if condition,
 230                  *    deletes the literal ^M, and falls through
 231                  *    into the magic-^M code
 232                  *  - receiving a magic-^M empties the line buffer,
 233                  *    signals end-of-line in one of the various
 234                  *    entertaining ways, and _doesn't_ fall out of
 235                  *    the bottom of the if and through to the
 236                  *    default clause because of the break.
 237                  */
 238               case CTRL('J'):
 239                 if (ldisc->cfg->protocol == PROT_RAW &&
 240                     ldisc->buflen > 0 && ldisc->buf[ldisc->buflen - 1] == '\r') {
 241                     if (ECHOING)
 242                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 243                     ldisc->buflen--;
 244                     /* FALLTHROUGH */
 245               case KCTRL('M'):         /* send with newline */
 246                     if (ldisc->buflen > 0)
 247                         ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 248                     if (ldisc->cfg->protocol == PROT_RAW)
 249                         ldisc->back->send(ldisc->backhandle, "\r\n", 2);
 250                     else if (ldisc->cfg->protocol == PROT_TELNET && ldisc->cfg->telnet_newline)
 251                         ldisc->back->special(ldisc->backhandle, TS_EOL);
 252                     else
 253                         ldisc->back->send(ldisc->backhandle, "\r", 1);
 254                     if (ECHOING)
 255                         c_write(ldisc, "\r\n", 2);
 256                     ldisc->buflen = 0;
 257                     break;
 258                 }
 259                 /* FALLTHROUGH */
 260               default:                 /* get to this label from ^V handler */
 261                 default_case:
 262                 if (ldisc->buflen >= ldisc->bufsiz) {
 263                     ldisc->bufsiz = ldisc->buflen + 256;
 264                     ldisc->buf = srealloc(ldisc->buf, ldisc->bufsiz);
 265                 }
 266                 ldisc->buf[ldisc->buflen++] = c;
 267                 if (ECHOING)
 268                     pwrite(ldisc, (unsigned char) c);
 269                 ldisc->quotenext = FALSE;
 270                 break;
 271             }
 272         }
 273     } else {
 274         if (ldisc->buflen != 0) {
 275             ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 276             while (ldisc->buflen > 0) {
 277                 bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 278                 ldisc->buflen--;
 279             }
 280         }
 281         if (len > 0) {
 282             if (ECHOING)
 283                 c_write(ldisc, buf, len);
 284             if (keyflag && ldisc->cfg->protocol == PROT_TELNET && len == 1) {
 285                 switch (buf[0]) {
 286                   case CTRL('M'):
 287                     if (ldisc->cfg->protocol == PROT_TELNET && ldisc->cfg->telnet_newline)
 288                         ldisc->back->special(ldisc->backhandle, TS_EOL);
 289                     else
 290                         ldisc->back->send(ldisc->backhandle, "\r", 1);
 291                     break;
 292                   case CTRL('?'):
 293                   case CTRL('H'):
 294                     if (ldisc->cfg->telnet_keyboard) {
 295                         ldisc->back->special(ldisc->backhandle, TS_EC);
 296                         break;
 297                     }
 298                   case CTRL('C'):
 299                     if (ldisc->cfg->telnet_keyboard) {
 300                         ldisc->back->special(ldisc->backhandle, TS_IP);
 301                         break;
 302                     }
 303                   case CTRL('Z'):
 304                     if (ldisc->cfg->telnet_keyboard) {
 305                         ldisc->back->special(ldisc->backhandle, TS_SUSP);
 306                         break;
 307                     }
 308
 309                   default:
 310                     ldisc->back->send(ldisc->backhandle, buf, len);
 311                     break;
 312                 }
 313             } else
 314                 ldisc->back->send(ldisc->backhandle, buf, len);
 315         }
 316     }
 317 }