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/*
* ldisc.c: PuTTY line discipline. Sits between the input coming
* from keypresses in the window, and the output channel leading to
* the back end. Implements echo and/or local line editing,
* depending on what's currently configured.
*/
#include <stdio.h>
#include <ctype.h>
#include "putty.h"
#include "terminal.h"
#include "ldisc.h"
#define ECHOING (ldisc->cfg->localecho == FORCE_ON || \
(ldisc->cfg->localecho == AUTO && \
(ldisc->back->ldisc(ldisc->backhandle, LD_ECHO) || \
term_ldisc(ldisc->term, LD_ECHO))))
#define EDITING (ldisc->cfg->localedit == FORCE_ON || \
(ldisc->cfg->localedit == AUTO && \
(ldisc->back->ldisc(ldisc->backhandle, LD_EDIT) || \
term_ldisc(ldisc->term, LD_EDIT))))
static void c_write(Ldisc ldisc, char *buf, int len)
{
from_backend(ldisc->frontend, 0, buf, len);
}
static int plen(Ldisc ldisc, unsigned char c)
{
if ((c >= 32 && c <= 126) || (c >= 160 && !in_utf(ldisc->term)))
return 1;
else if (c < 128)
return 2; /* ^x for some x */
else if (in_utf(ldisc->term) && c >= 0xC0)
return 1; /* UTF-8 introducer character
* (FIXME: combining / wide chars) */
else if (in_utf(ldisc->term) && c >= 0x80 && c < 0xC0)
return 0; /* UTF-8 followup character */
else
return 4; /* <XY> hex representation */
}
static void pwrite(Ldisc ldisc, unsigned char c)
{
if ((c >= 32 && c <= 126) ||
(!in_utf(ldisc->term) && c >= 0xA0) ||
(in_utf(ldisc->term) && c >= 0x80)) {
c_write(ldisc, (char *)&c, 1);
} else if (c < 128) {
char cc[2];
cc[1] = (c == 127 ? '?' : c + 0x40);
cc[0] = '^';
c_write(ldisc, cc, 2);
} else {
char cc[5];
sprintf(cc, "<%02X>", c);
c_write(ldisc, cc, 4);
}
}
static int char_start(Ldisc ldisc, unsigned char c)
{
if (in_utf(ldisc->term))
return (c < 0x80 || c >= 0xC0);
else
return 1;
}
static void bsb(Ldisc ldisc, int n)
{
while (n--)
c_write(ldisc, "\010 \010", 3);
}
#define CTRL(x) (x^'@')
#define KCTRL(x) ((x^'@') | 0x100)
void *ldisc_create(Config *mycfg, Terminal *term,
Backend *back, void *backhandle,
void *frontend)
{
Ldisc ldisc = snew(struct ldisc_tag);
ldisc->buf = NULL;
ldisc->buflen = 0;
ldisc->bufsiz = 0;
ldisc->quotenext = 0;
ldisc->cfg = mycfg;
ldisc->back = back;
ldisc->backhandle = backhandle;
ldisc->term = term;
ldisc->frontend = frontend;
/* Link ourselves into the backend and the terminal */
if (term)
term->ldisc = ldisc;
if (back)
back->provide_ldisc(backhandle, ldisc);
return ldisc;
}
void ldisc_free(void *handle)
{
Ldisc ldisc = (Ldisc) handle;
if (ldisc->term)
ldisc->term->ldisc = NULL;
if (ldisc->back)
ldisc->back->provide_ldisc(ldisc->backhandle, NULL);
if (ldisc->buf)
sfree(ldisc->buf);
sfree(ldisc);
}
void ldisc_send(void *handle, char *buf, int len, int interactive)
{
Ldisc ldisc = (Ldisc) handle;
int keyflag = 0;
/*
* Called with len=0 when the options change. We must inform
* the front end in case it needs to know.
*/
if (len == 0) {
ldisc_update(ldisc->frontend, ECHOING, EDITING);
return;
}
/*
* Notify the front end that something was pressed, in case
* it's depending on finding out (e.g. keypress termination for
* Close On Exit).
*/
frontend_keypress(ldisc->frontend);
/*
* Less than zero means null terminated special string.
*/
if (len < 0) {
len = strlen(buf);
keyflag = KCTRL('@');
}
/*
* Either perform local editing, or just send characters.
*/
if (EDITING) {
while (len--) {
int c;
c = (unsigned char)(*buf++) + keyflag;
if (!interactive && c == '\r')
c += KCTRL('@');
switch (ldisc->quotenext ? ' ' : c) {
/*
* ^h/^?: delete, and output BSBs, to return to
* last character boundary (in UTF-8 mode this may
* be more than one byte)
* ^w: delete, and output BSBs, to return to last
* space/nonspace boundary
* ^u: delete, and output BSBs, to return to BOL
* ^c: Do a ^u then send a telnet IP
* ^z: Do a ^u then send a telnet SUSP
* ^\: Do a ^u then send a telnet ABORT
* ^r: echo "^R\n" and redraw line
* ^v: quote next char
* ^d: if at BOL, end of file and close connection,
* else send line and reset to BOL
* ^m: send line-plus-\r\n and reset to BOL
*/
case KCTRL('H'):
case KCTRL('?'): /* backspace/delete */
if (ldisc->buflen > 0) {
do {
if (ECHOING)
bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
ldisc->buflen--;
} while (!char_start(ldisc, ldisc->buf[ldisc->buflen]));
}
break;
case CTRL('W'): /* delete word */
while (ldisc->buflen > 0) {
if (ECHOING)
bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
ldisc->buflen--;
if (ldisc->buflen > 0 &&
isspace((unsigned char)ldisc->buf[ldisc->buflen-1]) &&
!isspace((unsigned char)ldisc->buf[ldisc->buflen]))
break;
}
break;
case CTRL('U'): /* delete line */
case CTRL('C'): /* Send IP */
case CTRL('\\'): /* Quit */
case CTRL('Z'): /* Suspend */
while (ldisc->buflen > 0) {
if (ECHOING)
bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
ldisc->buflen--;
}
ldisc->back->special(ldisc->backhandle, TS_EL);
/*
* We don't send IP, SUSP or ABORT if the user has
* configured telnet specials off! This breaks
* talkers otherwise.
*/
if (!ldisc->cfg->telnet_keyboard)
goto default_case;
if (c == CTRL('C'))
ldisc->back->special(ldisc->backhandle, TS_IP);
if (c == CTRL('Z'))
ldisc->back->special(ldisc->backhandle, TS_SUSP);
if (c == CTRL('\\'))
ldisc->back->special(ldisc->backhandle, TS_ABORT);
break;
case CTRL('R'): /* redraw line */
if (ECHOING) {
int i;
c_write(ldisc, "^R\r\n", 4);
for (i = 0; i < ldisc->buflen; i++)
pwrite(ldisc, ldisc->buf[i]);
}
break;
case CTRL('V'): /* quote next char */
ldisc->quotenext = TRUE;
break;
case CTRL('D'): /* logout or send */
if (ldisc->buflen == 0) {
ldisc->back->special(ldisc->backhandle, TS_EOF);
} else {
ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
ldisc->buflen = 0;
}
break;
/*
* This particularly hideous bit of code from RDB
* allows ordinary ^M^J to do the same thing as
* magic-^M when in Raw protocol. The line `case
* KCTRL('M'):' is _inside_ the if block. Thus:
*
* - receiving regular ^M goes straight to the
* default clause and inserts as a literal ^M.
* - receiving regular ^J _not_ directly after a
* literal ^M (or not in Raw protocol) fails the
* if condition, leaps to the bottom of the if,
* and falls through into the default clause
* again.
* - receiving regular ^J just after a literal ^M
* in Raw protocol passes the if condition,
* deletes the literal ^M, and falls through
* into the magic-^M code
* - receiving a magic-^M empties the line buffer,
* signals end-of-line in one of the various
* entertaining ways, and _doesn't_ fall out of
* the bottom of the if and through to the
* default clause because of the break.
*/
case CTRL('J'):
if (ldisc->cfg->protocol == PROT_RAW &&
ldisc->buflen > 0 && ldisc->buf[ldisc->buflen - 1] == '\r') {
if (ECHOING)
bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
ldisc->buflen--;
/* FALLTHROUGH */
case KCTRL('M'): /* send with newline */
if (ldisc->buflen > 0)
ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
if (ldisc->cfg->protocol == PROT_RAW)
ldisc->back->send(ldisc->backhandle, "\r\n", 2);
else if (ldisc->cfg->protocol == PROT_TELNET && ldisc->cfg->telnet_newline)
ldisc->back->special(ldisc->backhandle, TS_EOL);
else
ldisc->back->send(ldisc->backhandle, "\r", 1);
if (ECHOING)
c_write(ldisc, "\r\n", 2);
ldisc->buflen = 0;
break;
}
/* FALLTHROUGH */
default: /* get to this label from ^V handler */
default_case:
if (ldisc->buflen >= ldisc->bufsiz) {
ldisc->bufsiz = ldisc->buflen + 256;
ldisc->buf = sresize(ldisc->buf, ldisc->bufsiz, char);
}
ldisc->buf[ldisc->buflen++] = c;
if (ECHOING)
pwrite(ldisc, (unsigned char) c);
ldisc->quotenext = FALSE;
break;
}
}
} else {
if (ldisc->buflen != 0) {
ldisc->back->send(ldisc->backhandle, ldisc->buf, ldisc->buflen);
while (ldisc->buflen > 0) {
bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
ldisc->buflen--;
}
}
if (len > 0) {
if (ECHOING)
c_write(ldisc, buf, len);
if (keyflag && ldisc->cfg->protocol == PROT_TELNET && len == 1) {
switch (buf[0]) {
case CTRL('M'):
if (ldisc->cfg->protocol == PROT_TELNET && ldisc->cfg->telnet_newline)
ldisc->back->special(ldisc->backhandle, TS_EOL);
else
ldisc->back->send(ldisc->backhandle, "\r", 1);
break;
case CTRL('?'):
case CTRL('H'):
if (ldisc->cfg->telnet_keyboard) {
ldisc->back->special(ldisc->backhandle, TS_EC);
break;
}
case CTRL('C'):
if (ldisc->cfg->telnet_keyboard) {
ldisc->back->special(ldisc->backhandle, TS_IP);
break;
}
case CTRL('Z'):
if (ldisc->cfg->telnet_keyboard) {
ldisc->back->special(ldisc->backhandle, TS_SUSP);
break;
}
default:
ldisc->back->send(ldisc->backhandle, buf, len);
break;
}
} else
ldisc->back->send(ldisc->backhandle, buf, len);
}
}
}
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