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 {
  23     from_backend(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))
  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)) {
  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
  63 void ldisc_send(char *buf, int len)
  64 {
  65     /*
  66      * Called with len=0 when the options change. We must inform
  67      * the front end in case it needs to know.
  68      */
  69     if (len == 0) {
  70         void ldisc_update(int echo, int edit);
  71         ldisc_update(ECHOING, EDITING);
  72     }
  73     /*
  74      * Either perform local editing, or just send characters.
  75      */
  76     if (EDITING) {
  77         while (len--) {
  78             char c;
  79             c = *buf++;
  80             switch (term_quotenext ? ' ' : c) {
  81                 /*
  82                  * ^h/^?: delete one char and output one BSB
  83                  * ^w: delete, and output BSBs, to return to last
  84                  * space/nonspace boundary
  85                  * ^u: delete, and output BSBs, to return to BOL
  86                  * ^c: Do a ^u then send a telnet IP
  87                  * ^z: Do a ^u then send a telnet SUSP
  88                  * ^\: Do a ^u then send a telnet ABORT
  89                  * ^r: echo "^R\n" and redraw line
  90                  * ^v: quote next char
  91                  * ^d: if at BOL, end of file and close connection,
  92                  * else send line and reset to BOL
  93                  * ^m: send line-plus-\r\n and reset to BOL
  94                  */
  95               case CTRL('H'):
  96               case CTRL('?'):          /* backspace/delete */
  97                 if (term_buflen > 0) {
  98                     if (ECHOING)
  99                         bsb(plen(term_buf[term_buflen - 1]));
 100                     term_buflen--;
 101                 }
 102                 break;
 103               case CTRL('W'):          /* delete word */
 104                 while (term_buflen > 0) {
 105                     if (ECHOING)
 106                         bsb(plen(term_buf[term_buflen - 1]));
 107                     term_buflen--;
 108                     if (term_buflen > 0 &&
 109                         isspace(term_buf[term_buflen - 1]) &&
 110                         !isspace(term_buf[term_buflen]))
 111                         break;
 112                 }
 113                 break;
 114               case CTRL('U'):          /* delete line */
 115               case CTRL('C'):          /* Send IP */
 116               case CTRL('\\'):         /* Quit */
 117               case CTRL('Z'):          /* Suspend */
 118                 while (term_buflen > 0) {
 119                     if (ECHOING)
 120                         bsb(plen(term_buf[term_buflen - 1]));
 121                     term_buflen--;
 122                 }
 123                 back->special(TS_EL);
 124                 if (c == CTRL('C'))
 125                     back->special(TS_IP);
 126                 if (c == CTRL('Z'))
 127                     back->special(TS_SUSP);
 128                 if (c == CTRL('\\'))
 129                     back->special(TS_ABORT);
 130                 break;
 131               case CTRL('R'):          /* redraw line */
 132                 if (ECHOING) {
 133                     int i;
 134                     c_write("^R\r\n", 4);
 135                     for (i = 0; i < term_buflen; i++)
 136                         pwrite(term_buf[i]);
 137                 }
 138                 break;
 139               case CTRL('V'):          /* quote next char */
 140                 term_quotenext = TRUE;
 141                 break;
 142               case CTRL('D'):          /* logout or send */
 143                 if (term_buflen == 0) {
 144                     back->special(TS_EOF);
 145                 } else {
 146                     back->send(term_buf, term_buflen);
 147                     term_buflen = 0;
 148                 }
 149                 break;
 150               case CTRL('M'):          /* send with newline */
 151                 if (term_buflen > 0)
 152                     back->send(term_buf, term_buflen);
 153                 if (cfg.protocol == PROT_RAW)
 154                     back->send("\r\n", 2);
 155                 else
 156                     back->send("\r", 1);
 157                 if (ECHOING)
 158                     c_write("\r\n", 2);
 159                 term_buflen = 0;
 160                 break;
 161               default:                 /* get to this label from ^V handler */
 162                 if (term_buflen >= term_bufsiz) {
 163                     term_bufsiz = term_buflen + 256;
 164                     term_buf = saferealloc(term_buf, term_bufsiz);
 165                 }
 166                 term_buf[term_buflen++] = c;
 167                 if (ECHOING)
 168                     pwrite(c);
 169                 term_quotenext = FALSE;
 170                 break;
 171             }
 172         }
 173     } else {
 174         if (term_buflen != 0) {
 175             back->send(term_buf, term_buflen);
 176             while (term_buflen > 0) {
 177                 bsb(plen(term_buf[term_buflen - 1]));
 178                 term_buflen--;
 179             }
 180         }
 181         if (len > 0) {
 182             if (ECHOING)
 183                 c_write(buf, len);
 184             back->send(buf, len);
 185         }
 186     }
 187 }