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 <windows.h>
   9 #include <stdio.h>
  10 #include <ctype.h>
  11
  12 #include "putty.h"
  13
  14 #define ECHOING (cfg.localecho == LD_YES || \
  15                  (cfg.localecho == LD_BACKEND && \
  16                       (back->ldisc(LD_ECHO) || term_ldisc(LD_ECHO))))
  17 #define EDITING (cfg.localedit == LD_YES || \
  18                  (cfg.localedit == LD_BACKEND && \
  19                       (back->ldisc(LD_EDIT) || term_ldisc(LD_EDIT))))
  20
  21 static void c_write (char *buf, int len) {
  22     from_backend(0, buf, len);
  23 }
  24
  25 static char *term_buf = NULL;
  26 static int term_buflen = 0, term_bufsiz = 0, term_quotenext = 0;
  27
  28 static int plen(unsigned char c) {
  29     if ((c >= 32 && c <= 126) ||
  30         (c >= 160))
  31         return 1;
  32     else if (c < 128)
  33         return 2;                      /* ^x for some x */
  34     else
  35         return 4;                      /* <XY> for hex XY */
  36 }
  37
  38 static void pwrite(unsigned char c) {
  39     if ((c >= 32 && c <= 126) ||
  40         (c >= 160)) {
  41         c_write(&c, 1);
  42     } else if (c < 128) {
  43         char cc[2];
  44         cc[1] = (c == 127 ? '?' : c + 0x40);
  45         cc[0] = '^';
  46         c_write(cc, 2);
  47     } else {
  48         char cc[5];
  49         sprintf(cc, "<%02X>", c);
  50         c_write(cc, 4);
  51     }
  52 }
  53
  54 static void bsb(int n) {
  55     while (n--)
  56         c_write("\010 \010", 3);
  57 }
  58
  59 #define CTRL(x) (x^'@')
  60
  61 void ldisc_send(char *buf, int len) {
  62     /*
  63      * Called with len=0 when the options change. We must inform
  64      * the front end in case it needs to know.
  65      */
  66     if (len == 0) {
  67         void ldisc_update(int echo, int edit);
  68         ldisc_update(ECHOING, EDITING);
  69     }
  70     /*
  71      * Either perform local editing, or just send characters.
  72      */
  73     if (EDITING) {
  74         while (len--) {
  75             char c;
  76             c = *buf++;
  77             switch (term_quotenext ? ' ' : c) {
  78                 /*
  79                  * ^h/^?: delete one char and output one BSB
  80                  * ^w: delete, and output BSBs, to return to last
  81                  * space/nonspace boundary
  82                  * ^u: delete, and output BSBs, to return to BOL
  83                  * ^c: Do a ^u then send a telnet IP
  84                  * ^z: Do a ^u then send a telnet SUSP
  85                  * ^\: Do a ^u then send a telnet ABORT
  86                  * ^r: echo "^R\n" and redraw line
  87                  * ^v: quote next char
  88                  * ^d: if at BOL, end of file and close connection,
  89                  * else send line and reset to BOL
  90                  * ^m: send line-plus-\r\n and reset to BOL
  91                  */
  92               case CTRL('H'): case CTRL('?'):      /* backspace/delete */
  93                 if (term_buflen > 0) {
  94                     if (ECHOING)
  95                         bsb(plen(term_buf[term_buflen-1]));
  96                     term_buflen--;
  97                 }
  98                 break;
  99               case CTRL('W'):                  /* delete word */
 100                 while (term_buflen > 0) {
 101                     if (ECHOING)
 102                         bsb(plen(term_buf[term_buflen-1]));
 103                     term_buflen--;
 104                     if (term_buflen > 0 &&
 105                         isspace(term_buf[term_buflen-1]) &&
 106                         !isspace(term_buf[term_buflen]))
 107                         break;
 108                 }
 109                 break;
 110               case CTRL('U'):          /* delete line */
 111               case CTRL('C'):          /* Send IP */
 112               case CTRL('\\'):         /* Quit */
 113               case CTRL('Z'):          /* Suspend */
 114                 while (term_buflen > 0) {
 115                     if (ECHOING)
 116                         bsb(plen(term_buf[term_buflen-1]));
 117                     term_buflen--;
 118                 }
 119                 back->special (TS_EL);
 120                 if( c == CTRL('C') )  back->special (TS_IP);
 121                 if( c == CTRL('Z') )  back->special (TS_SUSP);
 122                 if( c == CTRL('\\') ) back->special (TS_ABORT);
 123                 break;
 124               case CTRL('R'):          /* redraw line */
 125                 if (ECHOING) {
 126                     int i;
 127                     c_write("^R\r\n", 4);
 128                     for (i = 0; i < term_buflen; i++)
 129                         pwrite(term_buf[i]);
 130                 }
 131                 break;
 132               case CTRL('V'):          /* quote next char */
 133                 term_quotenext = TRUE;
 134                 break;
 135               case CTRL('D'):          /* logout or send */
 136                 if (term_buflen == 0) {
 137                     back->special (TS_EOF);
 138                 } else {
 139                     back->send(term_buf, term_buflen);
 140                     term_buflen = 0;
 141                 }
 142                 break;
 143               case CTRL('M'):          /* send with newline */
 144                 if (term_buflen > 0)
 145                     back->send(term_buf, term_buflen);
 146                 if (cfg.protocol == PROT_RAW)
 147                     back->send("\r\n", 2);
 148                 else
 149                     back->send("\r", 1);
 150                 if (ECHOING)
 151                     c_write("\r\n", 2);
 152                 term_buflen = 0;
 153                 break;
 154               default:                     /* get to this label from ^V handler */
 155                 if (term_buflen >= term_bufsiz) {
 156                     term_bufsiz = term_buflen + 256;
 157                     term_buf = saferealloc(term_buf, term_bufsiz);
 158                 }
 159                 term_buf[term_buflen++] = c;
 160                 if (ECHOING)
 161                     pwrite(c);
 162                 term_quotenext = FALSE;
 163                 break;
 164             }
 165         }
 166     } else {
 167         if( term_buflen != 0 )
 168         {
 169             back->send(term_buf, term_buflen);
 170             while (term_buflen > 0) {
 171                 bsb(plen(term_buf[term_buflen-1]));
 172                 term_buflen--;
 173             }
 174         }
 175         if (len > 0) {
 176             if (ECHOING)
 177                 c_write(buf, len);
 178             back->send(buf, len);
 179         }
 180     }
 181 }