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      * Less than zero means null terminated special string.
  78      */
  79     if (len < 0) {
  80         len = strlen(buf);
  81         keyflag = KCTRL('@');
  82     }
  83     /*
  84      * Either perform local editing, or just send characters.
  85      */
  86     if (EDITING) {
  87         while (len--) {
  88             int c;
  89             c = *buf++ + keyflag;
  90             if (!interactive && c == '\r')
  91                 c += KCTRL('@');
  92             switch (term_quotenext ? ' ' : c) {
  93                 /*
  94                  * ^h/^?: delete one char and output one BSB
  95                  * ^w: delete, and output BSBs, to return to last
  96                  * space/nonspace boundary
  97                  * ^u: delete, and output BSBs, to return to BOL
  98                  * ^c: Do a ^u then send a telnet IP
  99                  * ^z: Do a ^u then send a telnet SUSP
 100                  * ^\: Do a ^u then send a telnet ABORT
 101                  * ^r: echo "^R\n" and redraw line
 102                  * ^v: quote next char
 103                  * ^d: if at BOL, end of file and close connection,
 104                  * else send line and reset to BOL
 105                  * ^m: send line-plus-\r\n and reset to BOL
 106                  */
 107               case KCTRL('H'):
 108               case KCTRL('?'):         /* backspace/delete */
 109                 if (term_buflen > 0) {
 110                     if (ECHOING)
 111                         bsb(plen(term_buf[term_buflen - 1]));
 112                     term_buflen--;
 113                 }
 114                 break;
 115               case CTRL('W'):          /* delete word */
 116                 while (term_buflen > 0) {
 117                     if (ECHOING)
 118                         bsb(plen(term_buf[term_buflen - 1]));
 119                     term_buflen--;
 120                     if (term_buflen > 0 &&
 121                         isspace(term_buf[term_buflen - 1]) &&
 122                         !isspace(term_buf[term_buflen]))
 123                         break;
 124                 }
 125                 break;
 126               case CTRL('U'):          /* delete line */
 127               case CTRL('C'):          /* Send IP */
 128               case CTRL('\\'):         /* Quit */
 129               case CTRL('Z'):          /* Suspend */
 130                 while (term_buflen > 0) {
 131                     if (ECHOING)
 132                         bsb(plen(term_buf[term_buflen - 1]));
 133                     term_buflen--;
 134                 }
 135                 back->special(TS_EL);
 136                 /*
 137                  * We don't send IP, SUSP or ABORT if the user has
 138                  * configured telnet specials off! This breaks
 139                  * talkers otherwise.
 140                  */
 141                 if (!cfg.telnet_keyboard)
 142                     goto default_case;
 143                 if (c == CTRL('C'))
 144                     back->special(TS_IP);
 145                 if (c == CTRL('Z'))
 146                     back->special(TS_SUSP);
 147                 if (c == CTRL('\\'))
 148                     back->special(TS_ABORT);
 149                 break;
 150               case CTRL('R'):          /* redraw line */
 151                 if (ECHOING) {
 152                     int i;
 153                     c_write("^R\r\n", 4);
 154                     for (i = 0; i < term_buflen; i++)
 155                         pwrite(term_buf[i]);
 156                 }
 157                 break;
 158               case CTRL('V'):          /* quote next char */
 159                 term_quotenext = TRUE;
 160                 break;
 161               case CTRL('D'):          /* logout or send */
 162                 if (term_buflen == 0) {
 163                     back->special(TS_EOF);
 164                 } else {
 165                     back->send(term_buf, term_buflen);
 166                     term_buflen = 0;
 167                 }
 168                 break;
 169                 /*
 170                  * This particularly hideous bit of code from RDB
 171                  * allows ordinary ^M^J to do the same thing as
 172                  * magic-^M when in Raw protocol. The line `case
 173                  * KCTRL('M'):' is _inside_ the if block. Thus:
 174                  *
 175                  *  - receiving regular ^M goes straight to the
 176                  *    default clause and inserts as a literal ^M.
 177                  *  - receiving regular ^J _not_ directly after a
 178                  *    literal ^M (or not in Raw protocol) fails the
 179                  *    if condition, leaps to the bottom of the if,
 180                  *    and falls through into the default clause
 181                  *    again.
 182                  *  - receiving regular ^J just after a literal ^M
 183                  *    in Raw protocol passes the if condition,
 184                  *    deletes the literal ^M, and falls through
 185                  *    into the magic-^M code
 186                  *  - receiving a magic-^M empties the line buffer,
 187                  *    signals end-of-line in one of the various
 188                  *    entertaining ways, and _doesn't_ fall out of
 189                  *    the bottom of the if and through to the
 190                  *    default clause because of the break.
 191                  */
 192               case CTRL('J'):
 193                 if (cfg.protocol == PROT_RAW &&
 194                     term_buflen > 0 && term_buf[term_buflen - 1] == '\r') {
 195                     if (ECHOING)
 196                         bsb(plen(term_buf[term_buflen - 1]));
 197                     term_buflen--;
 198                     /* FALLTHROUGH */
 199               case KCTRL('M'):         /* send with newline */
 200                     if (term_buflen > 0)
 201                         back->send(term_buf, term_buflen);
 202                     if (cfg.protocol == PROT_RAW)
 203                         back->send("\r\n", 2);
 204                     else if (cfg.protocol == PROT_TELNET && cfg.telnet_newline)
 205                         back->special(TS_EOL);
 206                     else
 207                         back->send("\r", 1);
 208                     if (ECHOING)
 209                         c_write("\r\n", 2);
 210                     term_buflen = 0;
 211                     break;
 212                 }
 213                 /* FALLTHROUGH */
 214               default:                 /* get to this label from ^V handler */
 215                 default_case:
 216                 if (term_buflen >= term_bufsiz) {
 217                     term_bufsiz = term_buflen + 256;
 218                     term_buf = saferealloc(term_buf, term_bufsiz);
 219                 }
 220                 term_buf[term_buflen++] = c;
 221                 if (ECHOING)
 222                     pwrite((unsigned char) c);
 223                 term_quotenext = FALSE;
 224                 break;
 225             }
 226         }
 227     } else {
 228         if (term_buflen != 0) {
 229             back->send(term_buf, term_buflen);
 230             while (term_buflen > 0) {
 231                 bsb(plen(term_buf[term_buflen - 1]));
 232                 term_buflen--;
 233             }
 234         }
 235         if (len > 0) {
 236             if (ECHOING)
 237                 c_write(buf, len);
 238             if (keyflag && cfg.protocol == PROT_TELNET && len == 1) {
 239                 switch (buf[0]) {
 240                   case CTRL('M'):
 241                     if (cfg.protocol == PROT_TELNET && cfg.telnet_newline)
 242                         back->special(TS_EOL);
 243                     else
 244                         back->send("\r", 1);
 245                     break;
 246                   case CTRL('?'):
 247                   case CTRL('H'):
 248                     if (cfg.telnet_keyboard) {
 249                         back->special(TS_EC);
 250                         break;
 251                     }
 252                   case CTRL('C'):
 253                     if (cfg.telnet_keyboard) {
 254                         back->special(TS_IP);
 255                         break;
 256                     }
 257                   case CTRL('Z'):
 258                     if (cfg.telnet_keyboard) {
 259                         back->special(TS_SUSP);
 260                         break;
 261                     }
 262
 263                   default:
 264                     back->send(buf, len);
 265                     break;
 266                 }
 267             } else
 268                 back->send(buf, len);
 269         }
 270     }
 271 }