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