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->localecho == FORCE_ON || \
  16                  (ldisc->localecho == AUTO && \
  17                       (ldisc->back->ldisc(ldisc->backhandle, LD_ECHO) || \
  18                            term_ldisc(ldisc->term, LD_ECHO))))
  19 #define EDITING (ldisc->localedit == FORCE_ON || \
  20                  (ldisc->localedit == AUTO && \
  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->frontend, 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 if (in_utf(ldisc->term) && c >= 0xC0)
  36         return 1;                      /* UTF-8 introducer character
  37                                         * (FIXME: combining / wide chars) */
  38     else if (in_utf(ldisc->term) && c >= 0x80 && c < 0xC0)
  39         return 0;                      /* UTF-8 followup character */
  40     else
  41         return 4;                      /* <XY> hex representation */
  42 }
  43
  44 static void pwrite(Ldisc ldisc, unsigned char c)
  45 {
  46     if ((c >= 32 && c <= 126) ||
  47         (!in_utf(ldisc->term) && c >= 0xA0) ||
  48         (in_utf(ldisc->term) && c >= 0x80)) {
  49         c_write(ldisc, (char *)&c, 1);
  50     } else if (c < 128) {
  51         char cc[2];
  52         cc[1] = (c == 127 ? '?' : c + 0x40);
  53         cc[0] = '^';
  54         c_write(ldisc, cc, 2);
  55     } else {
  56         char cc[5];
  57         sprintf(cc, "<%02X>", c);
  58         c_write(ldisc, cc, 4);
  59     }
  60 }
  61
  62 static int char_start(Ldisc ldisc, unsigned char c)
  63 {
  64     if (in_utf(ldisc->term))
  65         return (c < 0x80 || c >= 0xC0);
  66     else
  67         return 1;
  68 }
  69
  70 static void bsb(Ldisc ldisc, int n)
  71 {
  72     while (n--)
  73         c_write(ldisc, "\010 \010", 3);
  74 }
  75
  76 #define CTRL(x) (x^'@')
  77 #define KCTRL(x) ((x^'@') | 0x100)
  78
  79 void *ldisc_create(Conf *conf, Terminal *term,
  80                    Backend *back, void *backhandle,
  81                    void *frontend)
  82 {
  83     Ldisc ldisc = snew(struct ldisc_tag);
  84
  85     ldisc->buf = NULL;
  86     ldisc->buflen = 0;
  87     ldisc->bufsiz = 0;
  88     ldisc->quotenext = 0;
  89
  90     ldisc->back = back;
  91     ldisc->backhandle = backhandle;
  92     ldisc->term = term;
  93     ldisc->frontend = frontend;
  94
  95     ldisc_configure(ldisc, conf);
  96
  97     /* Link ourselves into the backend and the terminal */
  98     if (term)
  99         term->ldisc = ldisc;
 100     if (back)
 101         back->provide_ldisc(backhandle, ldisc);
 102
 103     return ldisc;
 104 }
 105
 106 void ldisc_configure(void *handle, Conf *conf)
 107 {
 108     Ldisc ldisc = (Ldisc) handle;
 109
 110     ldisc->telnet_keyboard = conf_get_int(conf, CONF_telnet_keyboard);
 111     ldisc->telnet_newline = conf_get_int(conf, CONF_telnet_newline);
 112     ldisc->protocol = conf_get_int(conf, CONF_protocol);
 113     ldisc->localecho = conf_get_int(conf, CONF_localecho);
 114     ldisc->localedit = conf_get_int(conf, CONF_localedit);
 115 }
 116
 117 void ldisc_free(void *handle)
 118 {
 119     Ldisc ldisc = (Ldisc) handle;
 120
 121     if (ldisc->term)
 122         ldisc->term->ldisc = NULL;
 123     if (ldisc->back)
 124         ldisc->back->provide_ldisc(ldisc->backhandle, NULL);
 125     if (ldisc->buf)
 126         sfree(ldisc->buf);
 127     sfree(ldisc);
 128 }
 129
 130 void ldisc_send(void *handle, char *buf, int len, int interactive)
 131 {
 132     Ldisc ldisc = (Ldisc) handle;
 133     int keyflag = 0;
 134     /*
 135      * Called with len=0 when the options change. We must inform
 136      * the front end in case it needs to know.
 137      */
 138     if (len == 0) {
 139         ldisc_update(ldisc->frontend, ECHOING, EDITING);
 140         return;
 141     }
 142     /*
 143      * Notify the front end that something was pressed, in case
 144      * it's depending on finding out (e.g. keypress termination for
 145      * Close On Exit).
 146      */
 147     frontend_keypress(ldisc->frontend);
 148
 149     /*
 150      * Less than zero means null terminated special string.
 151      */
 152     if (len < 0) {
 153         len = strlen(buf);
 154         keyflag = KCTRL('@');
 155     }
 156     /*
 157      * Either perform local editing, or just send characters.
 158      */
 159     if (EDITING) {
 160         while (len--) {
 161             int c;
 162             c = (unsigned char)(*buf++) + keyflag;
 163             if (!interactive && c == '\r')
 164                 c += KCTRL('@');
 165             switch (ldisc->quotenext ? ' ' : c) {
 166                 /*
 167                  * ^h/^?: delete, and output BSBs, to return to
 168                  * last character boundary (in UTF-8 mode this may
 169                  * be more than one byte)
 170                  * ^w: delete, and output BSBs, to return to last
 171                  * space/nonspace boundary
 172                  * ^u: delete, and output BSBs, to return to BOL
 173                  * ^c: Do a ^u then send a telnet IP
 174                  * ^z: Do a ^u then send a telnet SUSP
 175                  * ^\: Do a ^u then send a telnet ABORT
 176                  * ^r: echo "^R\n" and redraw line
 177                  * ^v: quote next char
 178                  * ^d: if at BOL, end of file and close connection,
 179                  * else send line and reset to BOL
 180                  * ^m: send line-plus-\r\n and reset to BOL
 181                  */
 182               case KCTRL('H'):
 183               case KCTRL('?'):         /* backspace/delete */
 184                 if (ldisc->buflen > 0) {
 185                     do {
 186                         if (ECHOING)
 187                             bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 188                         ldisc->buflen--;
 189                     } while (!char_start(ldisc, ldisc->buf[ldisc->buflen]));
 190                 }
 191                 break;
 192               case CTRL('W'):          /* delete word */
 193                 while (ldisc->buflen > 0) {
 194                     if (ECHOING)
 195                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 196                     ldisc->buflen--;
 197                     if (ldisc->buflen > 0 &&
 198                         isspace((unsigned char)ldisc->buf[ldisc->buflen-1]) &&
 199                         !isspace((unsigned char)ldisc->buf[ldisc->buflen]))
 200                         break;
 201                 }
 202                 break;
 203               case CTRL('U'):          /* delete line */
 204               case CTRL('C'):          /* Send IP */
 205               case CTRL('\\'):         /* Quit */
 206               case CTRL('Z'):          /* Suspend */
 207                 while (ldisc->buflen > 0) {
 208                     if (ECHOING)
 209                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 210                     ldisc->buflen--;
 211                 }
 212                 ldisc->back->special(ldisc->backhandle, TS_EL);
 213                 /*
 214                  * We don't send IP, SUSP or ABORT if the user has
 215                  * configured telnet specials off! This breaks
 216                  * talkers otherwise.
 217                  */
 218                 if (!ldisc->telnet_keyboard)
 219                     goto default_case;
 220                 if (c == CTRL('C'))
 221                     ldisc->back->special(ldisc->backhandle, TS_IP);
 222                 if (c == CTRL('Z'))
 223                     ldisc->back->special(ldisc->backhandle, TS_SUSP);
 224                 if (c == CTRL('\\'))
 225                     ldisc->back->special(ldisc->backhandle, TS_ABORT);
 226                 break;
 227               case CTRL('R'):          /* redraw line */
 228                 if (ECHOING) {
 229                     int i;
 230                     c_write(ldisc, "^R\r\n", 4);
 231                     for (i = 0; i < ldisc->buflen; i++)
 232                         pwrite(ldisc, ldisc->buf[i]);
 233                 }
 234                 break;
 235               case CTRL('V'):          /* quote next char */
 236                 ldisc->quotenext = TRUE;
 237                 break;
 238               case CTRL('D'):          /* logout or send */
 239                 if (ldisc->buflen == 0) {
 240                     ldisc->back->special(ldisc->backhandle, TS_EOF);
 241                 } else {
 242                     ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 243                     ldisc->buflen = 0;
 244                 }
 245                 break;
 246                 /*
 247                  * This particularly hideous bit of code from RDB
 248                  * allows ordinary ^M^J to do the same thing as
 249                  * magic-^M when in Raw protocol. The line `case
 250                  * KCTRL('M'):' is _inside_ the if block. Thus:
 251                  *
 252                  *  - receiving regular ^M goes straight to the
 253                  *    default clause and inserts as a literal ^M.
 254                  *  - receiving regular ^J _not_ directly after a
 255                  *    literal ^M (or not in Raw protocol) fails the
 256                  *    if condition, leaps to the bottom of the if,
 257                  *    and falls through into the default clause
 258                  *    again.
 259                  *  - receiving regular ^J just after a literal ^M
 260                  *    in Raw protocol passes the if condition,
 261                  *    deletes the literal ^M, and falls through
 262                  *    into the magic-^M code
 263                  *  - receiving a magic-^M empties the line buffer,
 264                  *    signals end-of-line in one of the various
 265                  *    entertaining ways, and _doesn't_ fall out of
 266                  *    the bottom of the if and through to the
 267                  *    default clause because of the break.
 268                  */
 269               case CTRL('J'):
 270                 if (ldisc->protocol == PROT_RAW &&
 271                     ldisc->buflen > 0 && ldisc->buf[ldisc->buflen - 1] == '\r') {
 272                     if (ECHOING)
 273                         bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 274                     ldisc->buflen--;
 275                     /* FALLTHROUGH */
 276               case KCTRL('M'):         /* send with newline */
 277                     if (ldisc->buflen > 0)
 278                         ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 279                     if (ldisc->protocol == PROT_RAW)
 280                         ldisc->back->send(ldisc->backhandle, "\r\n", 2);
 281                     else if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
 282                         ldisc->back->special(ldisc->backhandle, TS_EOL);
 283                     else
 284                         ldisc->back->send(ldisc->backhandle, "\r", 1);
 285                     if (ECHOING)
 286                         c_write(ldisc, "\r\n", 2);
 287                     ldisc->buflen = 0;
 288                     break;
 289                 }
 290                 /* FALLTHROUGH */
 291               default:                 /* get to this label from ^V handler */
 292                 default_case:
 293                 if (ldisc->buflen >= ldisc->bufsiz) {
 294                     ldisc->bufsiz = ldisc->buflen + 256;
 295                     ldisc->buf = sresize(ldisc->buf, ldisc->bufsiz, char);
 296                 }
 297                 ldisc->buf[ldisc->buflen++] = c;
 298                 if (ECHOING)
 299                     pwrite(ldisc, (unsigned char) c);
 300                 ldisc->quotenext = FALSE;
 301                 break;
 302             }
 303         }
 304     } else {
 305         if (ldisc->buflen != 0) {
 306             ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
 307             while (ldisc->buflen > 0) {
 308                 bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
 309                 ldisc->buflen--;
 310             }
 311         }
 312         if (len > 0) {
 313             if (ECHOING)
 314                 c_write(ldisc, buf, len);
 315             if (keyflag && ldisc->protocol == PROT_TELNET && len == 1) {
 316                 switch (buf[0]) {
 317                   case CTRL('M'):
 318                     if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
 319                         ldisc->back->special(ldisc->backhandle, TS_EOL);
 320                     else
 321                         ldisc->back->send(ldisc->backhandle, "\r", 1);
 322                     break;
 323                   case CTRL('?'):
 324                   case CTRL('H'):
 325                     if (ldisc->telnet_keyboard) {
 326                         ldisc->back->special(ldisc->backhandle, TS_EC);
 327                         break;
 328                     }
 329                   case CTRL('C'):
 330                     if (ldisc->telnet_keyboard) {
 331                         ldisc->back->special(ldisc->backhandle, TS_IP);
 332                         break;
 333                     }
 334                   case CTRL('Z'):
 335                     if (ldisc->telnet_keyboard) {
 336                         ldisc->back->special(ldisc->backhandle, TS_SUSP);
 337                         break;
 338                     }
 339
 340                   default:
 341                     ldisc->back->send(ldisc->backhandle, buf, len);
 342                     break;
 343                 }
 344             } else
 345                 ldisc->back->send(ldisc->backhandle, buf, len);
 346         }
 347     }
 348 }