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