/*
* 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 <assert.h>
#include "putty.h"
#include "terminal.h"
#include "ldisc.h"
#define ECHOING (ldisc->localecho == FORCE_ON || \
(ldisc->localecho == AUTO && \
(backend_ldisc_option_state(ldisc->backend, LD_ECHO))))
#define EDITING (ldisc->localedit == FORCE_ON || \
(ldisc->localedit == AUTO && \
(backend_ldisc_option_state(ldisc->backend, LD_EDIT))))
static void c_write(Ldisc *ldisc, const void *buf, int len)
{
seat_stdout(ldisc->seat, 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, &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 bool char_start(Ldisc *ldisc, unsigned char c)
{
if (in_utf(ldisc->term))
return (c < 0x80 || c >= 0xC0);
else
return true;
}
static void bsb(Ldisc *ldisc, int n)
{
while (n--)
c_write(ldisc, "\010 \010", 3);
}
#define CTRL(x) (x^'@')
#define KCTRL(x) ((x^'@') | 0x100)
Ldisc *ldisc_create(Conf *conf, Terminal *term, Backend *backend, Seat *seat)
{
Ldisc *ldisc = snew(Ldisc);
ldisc->buf = NULL;
ldisc->buflen = 0;
ldisc->bufsiz = 0;
ldisc->quotenext = false;
ldisc->backend = backend;
ldisc->term = term;
ldisc->seat = seat;
ldisc_configure(ldisc, conf);
/* Link ourselves into the backend and the terminal */
if (term)
term->ldisc = ldisc;
if (backend)
backend_provide_ldisc(backend, ldisc);
return ldisc;
}
void ldisc_configure(Ldisc *ldisc, Conf *conf)
{
ldisc->telnet_keyboard = conf_get_bool(conf, CONF_telnet_keyboard);
ldisc->telnet_newline = conf_get_bool(conf, CONF_telnet_newline);
ldisc->protocol = conf_get_int(conf, CONF_protocol);
ldisc->localecho = conf_get_int(conf, CONF_localecho);
ldisc->localedit = conf_get_int(conf, CONF_localedit);
}
void ldisc_free(Ldisc *ldisc)
{
if (ldisc->term)
ldisc->term->ldisc = NULL;
if (ldisc->backend)
backend_provide_ldisc(ldisc->backend, NULL);
if (ldisc->buf)
sfree(ldisc->buf);
sfree(ldisc);
}
void ldisc_echoedit_update(Ldisc *ldisc)
{
seat_echoedit_update(ldisc->seat, ECHOING, EDITING);
}
void ldisc_send(Ldisc *ldisc, const void *vbuf, int len, bool interactive)
{
const char *buf = (const char *)vbuf;
int keyflag = 0;
assert(ldisc->term);
if (interactive) {
/*
* Interrupt a paste from the clipboard, if one was in
* progress when the user pressed a key. This is easier than
* buffering the current piece of data and saving it until the
* terminal has finished pasting, and has the potential side
* benefit of permitting a user to cancel an accidental huge
* paste.
*/
term_nopaste(ldisc->term);
}
/*
* 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--;
}
backend_special(ldisc->backend, SS_EL, 0);
/*
* We don't send IP, SUSP or ABORT if the user has
* configured telnet specials off! This breaks
* talkers otherwise.
*/
if (!ldisc->telnet_keyboard)
goto default_case;
if (c == CTRL('C'))
backend_special(ldisc->backend, SS_IP, 0);
if (c == CTRL('Z'))
backend_special(ldisc->backend, SS_SUSP, 0);
if (c == CTRL('\\'))
backend_special(ldisc->backend, SS_ABORT, 0);
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) {
backend_special(ldisc->backend, SS_EOF, 0);
} else {
backend_send(ldisc->backend, 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->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)
backend_send(ldisc->backend,
ldisc->buf, ldisc->buflen);
if (ldisc->protocol == PROT_RAW)
backend_send(ldisc->backend, "\r\n", 2);
else if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
backend_special(ldisc->backend, SS_EOL, 0);
else
backend_send(ldisc->backend, "\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:
sgrowarray(ldisc->buf, ldisc->bufsiz, ldisc->buflen);
ldisc->buf[ldisc->buflen++] = c;
if (ECHOING)
pwrite(ldisc, (unsigned char) c);
ldisc->quotenext = false;
break;
}
}
} else {
if (ldisc->buflen != 0) {
backend_send(ldisc->backend, 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->protocol == PROT_TELNET && len == 1) {
switch (buf[0]) {
case CTRL('M'):
if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
backend_special(ldisc->backend, SS_EOL, 0);
else
backend_send(ldisc->backend, "\r", 1);
break;
case CTRL('?'):
case CTRL('H'):
if (ldisc->telnet_keyboard) {
backend_special(ldisc->backend, SS_EC, 0);
break;
}
case CTRL('C'):
if (ldisc->telnet_keyboard) {
backend_special(ldisc->backend, SS_IP, 0);
break;
}
case CTRL('Z'):
if (ldisc->telnet_keyboard) {
backend_special(ldisc->backend, SS_SUSP, 0);
break;
}
default:
backend_send(ldisc->backend, buf, len);
break;
}
} else
backend_send(ldisc->backend, buf, len);
}
}
}