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phunix/minix/drivers/tty/tty/tty.c
David van Moolenbroek 391516dd77 tty/pty: unbreak stty(1) 
Change-Id: I3f857dcbb89e18c7db3a72f4bd6809beb7904bc0
2014-08-28 16:29:27 +00:00

1609 lines
46 KiB
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/* This file contains the terminal driver, both for the IBM console and regular
* ASCII terminals. It handles only the device-independent part of a TTY, the
* device dependent parts are in console.c, rs232.c, etc. This file contains
* two main entry points, tty_task() and tty_wakeup(), and several minor entry
* points for use by the device-dependent code.
*
* The device-independent part accepts "keyboard" input from the device-
* dependent part, performs input processing (special key interpretation),
* and sends the input to a process reading from the TTY. Output to a TTY
* is sent to the device-dependent code for output processing and "screen"
* display. Input processing is done by the device by calling 'in_process'
* on the input characters, output processing may be done by the device itself
* or by calling 'out_process'. The TTY takes care of input queuing, the
* device does the output queuing. If a device receives an external signal,
* like an interrupt, then it causes tty_wakeup() to be run by the CLOCK task
* to, you guessed it, wake up the TTY to check if input or output can
* continue.
*
* Changes:
* Jan 20, 2004 moved TTY driver to user-space (Jorrit N. Herder)
* Sep 20, 2004 local timer management/ sync alarms (Jorrit N. Herder)
* Jul 13, 2004 support for function key observers (Jorrit N. Herder)
*/
#include <assert.h>
#include <minix/drivers.h>
#include <minix/driver.h>
#include <termios.h>
#include <sys/kbdio.h>
#include <sys/ttycom.h>
#include <sys/ttydefaults.h>
#include <sys/fcntl.h>
#include <signal.h>
#include <minix/keymap.h>
#include "tty.h"
#include <sys/time.h>
#include <sys/select.h>
unsigned long rs_irq_set = 0;
/* Address of a tty structure. */
#define tty_addr(line) (&tty_table[line])
/* Macros for magic tty types. */
#define isconsole(tp) ((tp) < tty_addr(NR_CONS))
/* Macros for magic tty structure pointers. */
#define FIRST_TTY tty_addr(0)
#define END_TTY tty_addr(sizeof(tty_table) / sizeof(tty_table[0]))
/* A device exists if at least its 'devread' function is defined. */
#define tty_active(tp) ((tp)->tty_devread != NULL)
/* RS232 lines or pseudo terminals can be completely configured out. */
#if NR_RS_LINES == 0
#define rs_init(tp) ((void) 0)
#endif
struct kmessages kmess;
static void tty_timed_out(minix_timer_t *tp);
static void settimer(tty_t *tty_ptr, int enable);
static void in_transfer(tty_t *tp);
static int tty_echo(tty_t *tp, int ch);
static void rawecho(tty_t *tp, int ch);
static int back_over(tty_t *tp);
static void reprint(tty_t *tp);
static void dev_ioctl(tty_t *tp);
static void setattr(tty_t *tp);
static void tty_icancel(tty_t *tp);
static void tty_init(void);
static void do_new_kmess(void);
static void set_console_line(char term[CONS_ARG]);
static void set_kernel_color(char color[CONS_ARG]);
static void set_color(tty_t *tp, int color);
static void reset_color(tty_t *tp);
static int do_open(devminor_t minor, int access, endpoint_t user_endpt);
static int do_close(devminor_t minor);
static ssize_t do_read(devminor_t minor, u64_t position, endpoint_t endpt,
cp_grant_id_t grant, size_t size, int flags, cdev_id_t id);
static ssize_t do_write(devminor_t minor, u64_t position, endpoint_t endpt,
cp_grant_id_t grant, size_t size, int flags, cdev_id_t id);
static int do_ioctl(devminor_t minor, unsigned long request, endpoint_t endpt,
cp_grant_id_t grant, int flags, endpoint_t user_endpt, cdev_id_t id);
static int do_cancel(devminor_t minor, endpoint_t endpt, cdev_id_t id);
static int do_select(devminor_t minor, unsigned int ops, endpoint_t endpt);
static struct chardriver tty_tab = {
.cdr_open = do_open,
.cdr_close = do_close,
.cdr_read = do_read,
.cdr_write = do_write,
.cdr_ioctl = do_ioctl,
.cdr_cancel = do_cancel,
.cdr_select = do_select
};
/* Default attributes. */
static struct termios termios_defaults = {
.c_iflag = TTYDEF_IFLAG,
.c_oflag = TTYDEF_OFLAG,
.c_cflag = TTYDEF_CFLAG,
.c_lflag = TTYDEF_LFLAG,
.c_ispeed = TTYDEF_SPEED,
.c_ospeed = TTYDEF_SPEED,
.c_cc = {
[VEOF] = CEOF,
[VEOL] = CEOL,
[VERASE] = CERASE,
[VINTR] = CINTR,
[VKILL] = CKILL,
[VMIN] = CMIN,
[VQUIT] = CQUIT,
[VTIME] = CTIME,
[VSUSP] = CSUSP,
[VSTART] = CSTART,
[VSTOP] = CSTOP,
[VREPRINT] = CREPRINT,
[VLNEXT] = CLNEXT,
[VDISCARD] = CDISCARD,
[VSTATUS] = CSTATUS
}
};
static struct winsize winsize_defaults; /* = all zeroes */
/* Global variables for the TTY task (declared extern in tty.h). */
tty_t tty_table[NR_CONS+NR_RS_LINES];
int ccurrent; /* currently active console */
struct machine machine; /* kernel environment variables */
u32_t system_hz;
u32_t consoleline = CONS_MINOR;
u32_t kernel_msg_color = 0;
static const char lined[TTLINEDNAMELEN] = "termios"; /* line discipline */
/* SEF functions and variables. */
static void sef_local_startup(void);
static int sef_cb_init_fresh(int type, sef_init_info_t *info);
static void sef_cb_signal_handler(int signo);
extern struct minix_kerninfo *_minix_kerninfo;
/*===========================================================================*
* tty_task *
*===========================================================================*/
int main(void)
{
/* Main routine of the terminal task. */
message tty_mess; /* buffer for all incoming messages */
int ipc_status;
int line;
int r;
register tty_t *tp;
/* SEF local startup. */
sef_local_startup();
while (TRUE) {
/* Check for and handle any events on any of the ttys. */
for (tp = FIRST_TTY; tp < END_TTY; tp++) {
if (tp->tty_events) handle_events(tp);
}
/* Get a request message. */
r= driver_receive(ANY, &tty_mess, &ipc_status);
if (r != 0)
panic("driver_receive failed with: %d", r);
/* First handle all kernel notification types that the TTY supports.
* - An alarm went off, expire all timers and handle the events.
* - A hardware interrupt also is an invitation to check for events.
* - A new kernel message is available for printing.
* - Reset the console on system shutdown.
* Then see if this message is different from a normal device driver
* request and should be handled separately. These extra functions
* do not operate on a device, in constrast to the driver requests.
*/
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(tty_mess.m_source)) {
case CLOCK:
/* run watchdogs of expired timers */
expire_timers(tty_mess.m_notify.timestamp);
break;
case HARDWARE:
/* hardware interrupt notification */
#if NR_RS_LINES > 0
/* serial I/O */
if (tty_mess.m_notify.interrupts & rs_irq_set)
rs_interrupt(&tty_mess);
#endif
/* run watchdogs of expired timers */
expire_timers(tty_mess.m_notify.timestamp);
break;
default:
/* do nothing */
break;
}
/* done, get new message */
continue;
}
switch (tty_mess.m_type) {
case TTY_FKEY_CONTROL: /* (un)register a fkey observer */
do_fkey_ctl(&tty_mess);
continue;
case TTY_INPUT_UP:
case TTY_INPUT_EVENT:
do_input(&tty_mess);
continue;
default: /* should be a driver request */
; /* do nothing; end switch */
}
if (!IS_CDEV_RQ(tty_mess.m_type)) {
chardriver_process(&tty_tab, &tty_mess, ipc_status);
continue;
}
/* Only device requests should get to this point.
* All requests have a minor device number.
*/
if (OK != chardriver_get_minor(&tty_mess, &line))
continue;
if (line == VIDEO_MINOR) {
do_video(&tty_mess, ipc_status);
continue;
}
/* Execute the requested device driver function. */
chardriver_process(&tty_tab, &tty_mess, ipc_status);
}
return 0;
}
static void
set_color(tty_t *tp, int color)
{
char buf[8];
buf[0] = '\033';
snprintf(&buf[1], sizeof(buf) - 1, "[1;%dm", color);
do_write(tp->tty_minor, 0, KERNEL, (cp_grant_id_t) buf, sizeof(buf),
CDEV_NONBLOCK, 0);
}
static void
reset_color(tty_t *tp)
{
char buf[8];
#define SGR_COLOR_RESET 39
buf[0] = '\033';
snprintf(&buf[1], sizeof(buf) - 1, "[0;%dm", SGR_COLOR_RESET);
do_write(tp->tty_minor, 0, KERNEL, (cp_grant_id_t) buf, sizeof(buf),
CDEV_NONBLOCK, 0);
}
tty_t *
line2tty(devminor_t line)
{
/* Convert a terminal line to tty_table pointer */
tty_t* tp;
/* /dev/log goes to /dev/console, and both may be redirected. */
if (line == CONS_MINOR || line == LOG_MINOR)
line = consoleline;
if (line == VIDEO_MINOR) {
return(NULL);
} else if ((line - CONS_MINOR) < NR_CONS) {
tp = tty_addr(line - CONS_MINOR);
} else if ((line - RS232_MINOR) < NR_RS_LINES) {
tp = tty_addr(line - RS232_MINOR + NR_CONS);
} else {
tp = NULL;
}
if (tp != NULL && !tty_active(tp))
tp = NULL;
return(tp);
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
static void sef_local_startup()
{
/* Register init callbacks. */
sef_setcb_init_fresh(sef_cb_init_fresh);
sef_setcb_init_restart(sef_cb_init_fresh);
/* No live update support for now. */
/* Register signal callbacks. */
sef_setcb_signal_handler(sef_cb_signal_handler);
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
static int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
{
/* Initialize the tty driver. */
int r;
char val[CONS_ARG];
/* Get kernel environment (protected_mode, pc_at and ega are needed). */
if (OK != (r=sys_getmachine(&machine))) {
panic("Couldn't obtain kernel environment: %d", r);
}
if (env_get_param("console", val, sizeof(val)) == OK) {
set_console_line(val);
}
if ((r = env_get_param("kernelclr", val, sizeof(val))) == OK) {
set_kernel_color(val);
}
/* Initialize the TTY driver. */
tty_init();
/* Final one-time keyboard initialization. */
kb_init_once();
/* Register for diagnostics notifications. */
sys_diagctl_register();
return(OK);
}
static void
set_console_line(char term[CONS_ARG])
{
/* Parse 'term' and redirect console output there. */
int i;
/* Console */
if (!strncmp(term, "console", CONS_ARG - 1)) {
consoleline = CONS_MINOR+0;
}
/* The other console terminals */
for (i = 1; i < NR_CONS; i++) {
char cons[6];
strlcpy(cons, "ttyc0", sizeof(cons));
cons[4] += i;
if (!strncmp(term, cons,
CONS_ARG < sizeof(cons) ? CONS_ARG-1 : sizeof(cons) - 1))
consoleline = CONS_MINOR + i;
}
/* Serial lines */
assert(NR_RS_LINES <= 9);/* below assumes this is the case */
for (i = 0; i < NR_RS_LINES; i++) {
char sercons[6];
strlcpy(sercons, "tty00", sizeof(sercons));
sercons[4] += i;
if (!strncmp(term, sercons,
CONS_ARG < sizeof(sercons) ? CONS_ARG-1:sizeof(sercons)-1))
consoleline = RS232_MINOR + i;
}
}
static void
set_kernel_color(char color[CONS_ARG])
{
int def_color;
#define SGR_COLOR_START 30
#define SGR_COLOR_END 37
def_color = atoi(color);
if ((SGR_COLOR_START + def_color) >= SGR_COLOR_START &&
(SGR_COLOR_START + def_color) <= SGR_COLOR_END) {
kernel_msg_color = def_color + SGR_COLOR_START;
}
}
static void
do_new_kmess(void)
{
/* Kernel wants to print a new message */
struct kmessages *kmess_ptr; /* kmessages structure */
char kernel_buf_copy[_KMESS_BUF_SIZE];
static int prev_next = 0;
int next, bytes, copy, restore = 0;
tty_t *tp, rtp;
assert(_minix_kerninfo);
kmess_ptr = _minix_kerninfo->kmessages;
/* The kernel buffer is circular; print only the new part. Determine
* how many new bytes there are with the help of current and
* previous 'next' index. This works fine if less than _KMESS_BUF_SIZE
* bytes is new data; else we miss % _KMESS_BUF_SIZE here. Obtain
* 'next' only once, since we are operating on shared memory here.
* Check for size being positive; the buffer might as well be emptied!
*/
next = kmess_ptr->km_next;
bytes = ((next + _KMESS_BUF_SIZE) - prev_next) % _KMESS_BUF_SIZE;
if (bytes > 0) {
/* Copy from current position toward end of buffer */
copy = MIN(_KMESS_BUF_SIZE - prev_next, bytes);
memcpy(kernel_buf_copy, &kmess_ptr->km_buf[prev_next], copy);
/* Copy remainder from start of buffer */
if (copy < bytes) {
memcpy(&kernel_buf_copy[copy], &kmess_ptr->km_buf[0],
bytes - copy);
}
tp = line2tty(consoleline);
if (tp == NULL)
panic("Don't know where to send kernel messages");
if (tp->tty_outleft > 0) {
/* Terminal is already printing */
rtp = *tp; /* Make backup */
tp->tty_outleft = 0; /* So do_write is happy */
restore = 1;
}
if (kernel_msg_color != 0)
set_color(tp, kernel_msg_color);
do_write(tp->tty_minor, 0, KERNEL,
(cp_grant_id_t) kernel_buf_copy, bytes,
CDEV_NONBLOCK, 0);
if (kernel_msg_color != 0)
reset_color(tp);
if (restore) {
*tp = rtp;
}
}
/* Store 'next' pointer so that we can determine what part of the
* kernel messages buffer to print next time a notification arrives.
*/
prev_next = next;
}
/*===========================================================================*
* sef_cb_signal_handler *
*===========================================================================*/
static void sef_cb_signal_handler(int signo)
{
/* Check for known signals, ignore anything else. */
switch(signo) {
/* There is a pending message from the kernel. */
case SIGKMESS:
do_new_kmess();
break;
/* Switch to primary console on termination. */
case SIGTERM:
cons_stop();
break;
}
}
/*===========================================================================*
* do_read *
*===========================================================================*/
static ssize_t do_read(devminor_t minor, u64_t UNUSED(position),
endpoint_t endpt, cp_grant_id_t grant, size_t size, int flags,
cdev_id_t id)
{
/* A process wants to read from a terminal. */
tty_t *tp;
int r;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
/* Check if there is already a process hanging in a read, check if the
* parameters are correct, do I/O.
*/
if (tp->tty_incaller != NONE || tp->tty_inleft > 0)
return EIO;
if (size <= 0)
return EINVAL;
/* Copy information from the message to the tty struct. */
tp->tty_incaller = endpt;
tp->tty_inid = id;
tp->tty_ingrant = grant;
assert(tp->tty_incum == 0);
tp->tty_inleft = size;
if (!(tp->tty_termios.c_lflag & ICANON) && tp->tty_termios.c_cc[VTIME] > 0) {
if (tp->tty_termios.c_cc[VMIN] == 0) {
/* MIN & TIME specify a read timer that finishes the
* read in TIME/10 seconds if no bytes are available.
*/
settimer(tp, TRUE);
tp->tty_min = 1;
} else {
/* MIN & TIME specify an inter-byte timer that may
* have to be cancelled if there are no bytes yet.
*/
if (tp->tty_eotct == 0) {
settimer(tp, FALSE);
tp->tty_min = tp->tty_termios.c_cc[VMIN];
}
}
}
/* Anything waiting in the input buffer? Clear it out... */
in_transfer(tp);
/* ...then go back for more. */
handle_events(tp);
if (tp->tty_inleft == 0)
return EDONTREPLY; /* already done */
/* There were no bytes in the input queue available. */
if (flags & CDEV_NONBLOCK) {
tty_icancel(tp);
r = tp->tty_incum > 0 ? tp->tty_incum : EAGAIN;
tp->tty_inleft = tp->tty_incum = 0;
tp->tty_incaller = NONE;
return r;
}
if (tp->tty_select_ops)
select_retry(tp);
return EDONTREPLY; /* suspend the caller */
}
/*===========================================================================*
* do_write *
*===========================================================================*/
static ssize_t do_write(devminor_t minor, u64_t UNUSED(position),
endpoint_t endpt, cp_grant_id_t grant, size_t size, int flags,
cdev_id_t id)
{
/* A process wants to write on a terminal. */
tty_t *tp;
int r;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
/* Check if there is already a process hanging in a write, check if the
* parameters are correct, do I/O.
*/
if (tp->tty_outcaller != NONE || tp->tty_outleft > 0)
return EIO;
if (size <= 0)
return EINVAL;
/* Copy message parameters to the tty structure. */
tp->tty_outcaller = endpt;
tp->tty_outid = id;
tp->tty_outgrant = grant;
assert(tp->tty_outcum == 0);
tp->tty_outleft = size;
/* Try to write. */
handle_events(tp);
if (tp->tty_outleft == 0)
return EDONTREPLY; /* already done */
/* None or not all the bytes could be written. */
if (flags & CDEV_NONBLOCK) {
r = tp->tty_outcum > 0 ? tp->tty_outcum : EAGAIN;
tp->tty_outleft = tp->tty_outcum = 0;
tp->tty_outcaller = NONE;
return r;
}
if (tp->tty_select_ops)
select_retry(tp);
return EDONTREPLY; /* suspend the caller */
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
static int do_ioctl(devminor_t minor, unsigned long request, endpoint_t endpt,
cp_grant_id_t grant, int flags, endpoint_t user_endpt, cdev_id_t id)
{
/* Perform an IOCTL on this terminal. POSIX termios calls are handled
* by the IOCTL system call.
*/
kio_bell_t bell;
clock_t ticks;
tty_t *tp;
int i, r;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
r = OK;
switch (request) {
case TIOCGETA:
/* Get the termios attributes. */
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) &tp->tty_termios,
sizeof(struct termios));
break;
case TIOCSETAW:
case TIOCSETAF:
case TIOCDRAIN:
if (tp->tty_outleft > 0) {
if (flags & CDEV_NONBLOCK)
return EAGAIN;
/* Wait for all ongoing output processing to finish. */
tp->tty_iocaller = endpt;
tp->tty_ioid = id;
tp->tty_ioreq = request;
tp->tty_iogrant = grant;
return EDONTREPLY; /* suspend the caller */
}
if (request == TIOCDRAIN) break;
if (request == TIOCSETAF) tty_icancel(tp);
/*FALL THROUGH*/
case TIOCSETA:
/* Set the termios attributes. */
r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &tp->tty_termios,
sizeof(struct termios));
if (r != OK) break;
setattr(tp);
break;
case TIOCFLUSH:
r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &i, sizeof(i));
if (r != OK) break;
if(i & FREAD) { tty_icancel(tp); }
if(i & FWRITE) { (*tp->tty_ocancel)(tp, 0); }
break;
case TIOCSTART:
tp->tty_inhibited = 0;
tp->tty_events = 1;
break;
case TIOCSTOP:
tp->tty_inhibited = 1;
tp->tty_events = 1;
break;
case TIOCSBRK: /* tcsendbreak - turn break on */
if (tp->tty_break_on != NULL) (*tp->tty_break_on)(tp,0);
break;
case TIOCCBRK: /* tcsendbreak - turn break off */
if (tp->tty_break_off != NULL) (*tp->tty_break_off)(tp,0);
break;
case TIOCGWINSZ:
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) &tp->tty_winsize,
sizeof(struct winsize));
break;
case TIOCSWINSZ:
r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &tp->tty_winsize,
sizeof(struct winsize));
sigchar(tp, SIGWINCH, 0);
break;
case KIOCBELL:
/* Sound bell (only /dev/console). */
if (!isconsole(tp))
break;
r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &bell, sizeof(bell));
if (r != OK)
break;
ticks = bell.kb_duration.tv_usec * system_hz / 1000000;
ticks += bell.kb_duration.tv_sec * system_hz;
if (!ticks)
ticks++;
beep_x(bell.kb_pitch, ticks);
break;
case TIOCGETD: /* get line discipline */
i = TTYDISC;
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) &i, sizeof(i));
break;
case TIOCSETD: /* set line discipline */
printf("TTY: TIOCSETD: can't set any other line discipline.\n");
r = ENOTTY;
break;
case TIOCGLINED: /* get line discipline as string */
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) lined, sizeof(lined));
break;
case TIOCGQSIZE: /* get input/output queue sizes */
i = TTY_IN_BYTES; /* best we can do.. */
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) &i, sizeof(i));
break;
case KIOCSMAP:
/* Load a new keymap (only /dev/console). */
if (isconsole(tp)) r = kbd_loadmap(endpt, grant);
break;
case TIOCSFON:
/* Load a font into an EGA or VGA card (hs@hck.hr) */
if (isconsole(tp)) r = con_loadfont(endpt, grant);
break;
case TIOCSCTTY:
/* Process sets this tty as its controlling tty */
tp->tty_pgrp = user_endpt;
break;
/* These Posix functions are allowed to fail if _POSIX_JOB_CONTROL is
* not defined.
*/
case TIOCGPGRP:
case TIOCSPGRP:
default:
r = ENOTTY;
}
return r;
}
/*===========================================================================*
* do_open *
*===========================================================================*/
static int do_open(devminor_t minor, int access, endpoint_t user_endpt)
{
/* A tty line has been opened. Make it the callers controlling tty if
* CDEV_NOCTTY is *not* set and it is not the log device. CDEV_CTTY is returned
* if the tty is made the controlling tty, otherwise OK or an error code.
*/
tty_t *tp;
int r = OK;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
if (minor == LOG_MINOR && isconsole(tp)) {
/* The log device is a write-only diagnostics device. */
if (access & CDEV_R_BIT) return EACCES;
} else {
if (!(access & CDEV_NOCTTY)) {
tp->tty_pgrp = user_endpt;
r = CDEV_CTTY;
}
tp->tty_openct++;
if (tp->tty_openct == 1) {
/* Tell the device that the tty is opened */
(*tp->tty_open)(tp, 0);
}
}
return r;
}
/*===========================================================================*
* do_close *
*===========================================================================*/
static int do_close(devminor_t minor)
{
/* A tty line has been closed. Clean up the line if it is the last close. */
tty_t *tp;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
if ((minor != LOG_MINOR || !isconsole(tp)) && --tp->tty_openct == 0) {
tp->tty_pgrp = 0;
tty_icancel(tp);
(*tp->tty_ocancel)(tp, 0);
(*tp->tty_close)(tp, 0);
tp->tty_termios = termios_defaults;
tp->tty_winsize = winsize_defaults;
setattr(tp);
}
return OK;
}
/*===========================================================================*
* do_cancel *
*===========================================================================*/
static int do_cancel(devminor_t minor, endpoint_t endpt, cdev_id_t id)
{
/* A signal has been sent to a process that is hanging trying to read or write.
* The pending read or write must be finished off immediately.
*/
tty_t *tp;
int r;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
/* Check the parameters carefully, to avoid cancelling twice. */
r = EDONTREPLY;
if (tp->tty_inleft != 0 && endpt == tp->tty_incaller && id == tp->tty_inid) {
/* Process was reading when killed. Clean up input. */
tty_icancel(tp);
r = tp->tty_incum > 0 ? tp->tty_incum : EAGAIN;
tp->tty_inleft = tp->tty_incum = 0;
tp->tty_incaller = NONE;
} else if (tp->tty_outleft != 0 && endpt == tp->tty_outcaller &&
id == tp->tty_outid) {
/* Process was writing when killed. Clean up output. */
r = tp->tty_outcum > 0 ? tp->tty_outcum : EAGAIN;
tp->tty_outleft = tp->tty_outcum = 0;
tp->tty_outcaller = NONE;
} else if (tp->tty_ioreq != 0 && endpt == tp->tty_iocaller &&
id == tp->tty_ioid) {
/* Process was waiting for output to drain. */
r = EINTR;
tp->tty_ioreq = 0;
tp->tty_iocaller = NONE;
}
if (r != EDONTREPLY)
tp->tty_events = 1;
/* Only reply if we found a matching request. */
return r;
}
int select_try(struct tty *tp, int ops)
{
int ready_ops = 0;
/* Special case. If line is hung up, no operations will block.
* (and it can be seen as an exceptional condition.)
*/
if (tp->tty_termios.c_ospeed == B0) {
ready_ops |= ops;
}
if (ops & CDEV_OP_RD) {
/* will i/o not block on read? */
if (tp->tty_inleft > 0) {
ready_ops |= CDEV_OP_RD; /* EIO - no blocking */
} else if (tp->tty_incount > 0) {
/* Is a regular read possible? tty_incount
* says there is data. But a read will only succeed
* in canonical mode if a newline has been seen.
*/
if (!(tp->tty_termios.c_lflag & ICANON) ||
tp->tty_eotct > 0) {
ready_ops |= CDEV_OP_RD;
}
}
}
if (ops & CDEV_OP_WR) {
if (tp->tty_outleft > 0) ready_ops |= CDEV_OP_WR;
else if ((*tp->tty_devwrite)(tp, 1)) ready_ops |= CDEV_OP_WR;
}
return ready_ops;
}
int select_retry(struct tty *tp)
{
int ops;
if (tp->tty_select_ops && (ops = select_try(tp, tp->tty_select_ops))) {
chardriver_reply_select(tp->tty_select_proc,
tp->tty_select_minor, ops);
tp->tty_select_ops &= ~ops;
}
return OK;
}
/*===========================================================================*
* do_select *
*===========================================================================*/
static int do_select(devminor_t minor, unsigned int ops, endpoint_t endpt)
{
tty_t *tp;
int ready_ops, watch;
if ((tp = line2tty(minor)) == NULL)
return ENXIO;
watch = (ops & CDEV_NOTIFY);
ops &= (CDEV_OP_RD | CDEV_OP_WR | CDEV_OP_ERR);
ready_ops = select_try(tp, ops);
ops &= ~ready_ops;
if (ops && watch) {
/* Translated minor numbers are a problem with late select replies. We
* have to save the minor number used to do the select, since otherwise
* VFS won't be able to make sense of those late replies. We do not
* support selecting on two different minors for the same object.
*/
if (tp->tty_select_ops != 0 && tp->tty_select_minor != minor) {
printf("TTY: select on one object with two minors (%d, %d)\n",
tp->tty_select_minor, minor);
return EBADF;
}
tp->tty_select_ops |= ops;
tp->tty_select_proc = endpt;
tp->tty_select_minor = minor;
}
return ready_ops;
}
/*===========================================================================*
* handle_events *
*===========================================================================*/
void handle_events(tp)
tty_t *tp; /* TTY to check for events. */
{
/* Handle any events pending on a TTY. These events are usually device
* interrupts.
*
* Two kinds of events are prominent:
* - a character has been received from the console or an RS232 line.
* - an RS232 line has completed a write request (on behalf of a user).
* The interrupt handler may delay the interrupt message at its discretion
* to avoid swamping the TTY task. Messages may be overwritten when the
* lines are fast or when there are races between different lines, input
* and output, because MINIX only provides single buffering for interrupt
* messages. This is handled by explicitly checking each line for fresh input
* and completed output on each interrupt.
*/
do {
tp->tty_events = 0;
/* Read input and perform input processing. */
(*tp->tty_devread)(tp, 0);
/* Perform output processing and write output. */
(*tp->tty_devwrite)(tp, 0);
/* Ioctl waiting for some event? */
if (tp->tty_ioreq != 0) dev_ioctl(tp);
} while (tp->tty_events);
/* Transfer characters from the input queue to a waiting process. */
in_transfer(tp);
/* Reply if enough bytes are available. */
if (tp->tty_incum >= tp->tty_min && tp->tty_inleft > 0) {
chardriver_reply_task(tp->tty_incaller, tp->tty_inid, tp->tty_incum);
tp->tty_inleft = tp->tty_incum = 0;
tp->tty_incaller = NONE;
}
if (tp->tty_select_ops)
{
select_retry(tp);
}
}
/*===========================================================================*
* in_transfer *
*===========================================================================*/
static void in_transfer(tp)
register tty_t *tp; /* pointer to terminal to read from */
{
/* Transfer bytes from the input queue to a process reading from a terminal. */
int ch;
int count;
char buf[64], *bp;
/* Force read to succeed if the line is hung up, looks like EOF to reader. */
if (tp->tty_termios.c_ospeed == B0) tp->tty_min = 0;
/* Anything to do? */
if (tp->tty_inleft == 0 || tp->tty_eotct < tp->tty_min) return;
bp = buf;
while (tp->tty_inleft > 0 && tp->tty_eotct > 0) {
ch = *tp->tty_intail;
if (!(ch & IN_EOF)) {
/* One character to be delivered to the user. */
*bp = ch & IN_CHAR;
tp->tty_inleft--;
if (++bp == bufend(buf)) {
/* Temp buffer full, copy to user space. */
sys_safecopyto(tp->tty_incaller,
tp->tty_ingrant, tp->tty_incum,
(vir_bytes) buf, (vir_bytes) buflen(buf));
tp->tty_incum += buflen(buf);
bp = buf;
}
}
/* Remove the character from the input queue. */
if (++tp->tty_intail == bufend(tp->tty_inbuf))
tp->tty_intail = tp->tty_inbuf;
tp->tty_incount--;
if (ch & IN_EOT) {
tp->tty_eotct--;
/* Don't read past a line break in canonical mode. */
if (tp->tty_termios.c_lflag & ICANON) tp->tty_inleft = 0;
}
}
if (bp > buf) {
/* Leftover characters in the buffer. */
count = bp - buf;
sys_safecopyto(tp->tty_incaller, tp->tty_ingrant, tp->tty_incum,
(vir_bytes) buf, (vir_bytes) count);
tp->tty_incum += count;
}
/* Usually reply to the reader, possibly even if incum == 0 (EOF). */
if (tp->tty_inleft == 0) {
chardriver_reply_task(tp->tty_incaller, tp->tty_inid, tp->tty_incum);
tp->tty_inleft = tp->tty_incum = 0;
tp->tty_incaller = NONE;
}
}
/*===========================================================================*
* in_process *
*===========================================================================*/
int in_process(tp, buf, count)
register tty_t *tp; /* terminal on which character has arrived */
char *buf; /* buffer with input characters */
int count; /* number of input characters */
{
/* Characters have just been typed in. Process, save, and echo them. Return
* the number of characters processed.
*/
int ch, sig, ct;
int timeset = FALSE;
for (ct = 0; ct < count; ct++) {
/* Take one character. */
ch = *buf++ & BYTE;
/* Strip to seven bits? */
if (tp->tty_termios.c_iflag & ISTRIP) ch &= 0x7F;
/* Input extensions? */
if (tp->tty_termios.c_lflag & IEXTEN) {
/* Previous character was a character escape? */
if (tp->tty_escaped) {
tp->tty_escaped = NOT_ESCAPED;
ch |= IN_ESC; /* protect character */
}
/* LNEXT (^V) to escape the next character? */
if (ch == tp->tty_termios.c_cc[VLNEXT]) {
tp->tty_escaped = ESCAPED;
rawecho(tp, '^');
rawecho(tp, '\b');
continue; /* do not store the escape */
}
/* REPRINT (^R) to reprint echoed characters? */
if (ch == tp->tty_termios.c_cc[VREPRINT]) {
reprint(tp);
continue;
}
}
/* _POSIX_VDISABLE is a normal character value, so better escape it. */
if (ch == _POSIX_VDISABLE) ch |= IN_ESC;
/* Map CR to LF, ignore CR, or map LF to CR. */
if (ch == '\r') {
if (tp->tty_termios.c_iflag & IGNCR) continue;
if (tp->tty_termios.c_iflag & ICRNL) ch = '\n';
} else
if (ch == '\n') {
if (tp->tty_termios.c_iflag & INLCR) ch = '\r';
}
/* Canonical mode? */
if (tp->tty_termios.c_lflag & ICANON) {
/* Erase processing (rub out of last character). */
if (ch == tp->tty_termios.c_cc[VERASE]) {
(void) back_over(tp);
if (!(tp->tty_termios.c_lflag & ECHOE)) {
(void) tty_echo(tp, ch);
}
continue;
}
/* Kill processing (remove current line). */
if (ch == tp->tty_termios.c_cc[VKILL]) {
while (back_over(tp)) {}
if (!(tp->tty_termios.c_lflag & ECHOE)) {
(void) tty_echo(tp, ch);
if (tp->tty_termios.c_lflag & ECHOK)
rawecho(tp, '\n');
}
continue;
}
/* EOF (^D) means end-of-file, an invisible "line break". */
if (ch == tp->tty_termios.c_cc[VEOF]) ch |= IN_EOT | IN_EOF;
/* The line may be returned to the user after an LF. */
if (ch == '\n') ch |= IN_EOT;
/* Same thing with EOL, whatever it may be. */
if (ch == tp->tty_termios.c_cc[VEOL]) ch |= IN_EOT;
}
/* Start/stop input control? */
if (tp->tty_termios.c_iflag & IXON) {
/* Output stops on STOP (^S). */
if (ch == tp->tty_termios.c_cc[VSTOP]) {
tp->tty_inhibited = STOPPED;
tp->tty_events = 1;
continue;
}
/* Output restarts on START (^Q) or any character if IXANY. */
if (tp->tty_inhibited) {
if (ch == tp->tty_termios.c_cc[VSTART]
|| (tp->tty_termios.c_iflag & IXANY)) {
tp->tty_inhibited = RUNNING;
tp->tty_events = 1;
if (ch == tp->tty_termios.c_cc[VSTART])
continue;
}
}
}
if (tp->tty_termios.c_lflag & ISIG) {
/* Check for INTR, QUIT and STATUS characters. */
int sig = -1;
if (ch == tp->tty_termios.c_cc[VINTR])
sig = SIGINT;
else if(ch == tp->tty_termios.c_cc[VQUIT])
sig = SIGQUIT;
else if(ch == tp->tty_termios.c_cc[VSTATUS])
sig = SIGINFO;
if(sig >= 0) {
sigchar(tp, sig, 1);
(void) tty_echo(tp, ch);
continue;
}
}
/* Is there space in the input buffer? */
if (tp->tty_incount == buflen(tp->tty_inbuf)) {
/* No space; discard in canonical mode, keep in raw mode. */
if (tp->tty_termios.c_lflag & ICANON) continue;
break;
}
if (!(tp->tty_termios.c_lflag & ICANON)) {
/* In raw mode all characters are "line breaks". */
ch |= IN_EOT;
/* Start an inter-byte timer? */
if (!timeset && tp->tty_termios.c_cc[VMIN] > 0
&& tp->tty_termios.c_cc[VTIME] > 0) {
settimer(tp, TRUE);
timeset = TRUE;
}
}
/* Perform the intricate function of echoing. */
if (tp->tty_termios.c_lflag & (ECHO|ECHONL)) ch = tty_echo(tp, ch);
/* Save the character in the input queue. */
*tp->tty_inhead++ = ch;
if (tp->tty_inhead == bufend(tp->tty_inbuf))
tp->tty_inhead = tp->tty_inbuf;
tp->tty_incount++;
if (ch & IN_EOT) tp->tty_eotct++;
/* Try to finish input if the queue threatens to overflow. */
if (tp->tty_incount == buflen(tp->tty_inbuf)) in_transfer(tp);
}
return ct;
}
/*===========================================================================*
* echo *
*===========================================================================*/
static int tty_echo(tp, ch)
register tty_t *tp; /* terminal on which to echo */
register int ch; /* pointer to character to echo */
{
/* Echo the character if echoing is on. Some control characters are echoed
* with their normal effect, other control characters are echoed as "^X",
* normal characters are echoed normally. EOF (^D) is echoed, but immediately
* backspaced over. Return the character with the echoed length added to its
* attributes.
*/
int len, rp;
ch &= ~IN_LEN;
if (!(tp->tty_termios.c_lflag & ECHO)) {
if (ch == ('\n' | IN_EOT) && (tp->tty_termios.c_lflag
& (ICANON|ECHONL)) == (ICANON|ECHONL))
(*tp->tty_echo)(tp, '\n');
return(ch);
}
/* "Reprint" tells if the echo output has been messed up by other output. */
rp = tp->tty_incount == 0 ? FALSE : tp->tty_reprint;
if ((ch & IN_CHAR) < ' ') {
switch (ch & (IN_ESC|IN_EOF|IN_EOT|IN_CHAR)) {
case '\t':
len = 0;
do {
(*tp->tty_echo)(tp, ' ');
len++;
} while (len < TAB_SIZE && (tp->tty_position & TAB_MASK) != 0);
break;
case '\r' | IN_EOT:
case '\n' | IN_EOT:
(*tp->tty_echo)(tp, ch & IN_CHAR);
len = 0;
break;
default:
(*tp->tty_echo)(tp, '^');
(*tp->tty_echo)(tp, '@' + (ch & IN_CHAR));
len = 2;
}
} else
if ((ch & IN_CHAR) == '\177') {
/* A DEL prints as "^?". */
(*tp->tty_echo)(tp, '^');
(*tp->tty_echo)(tp, '?');
len = 2;
} else {
(*tp->tty_echo)(tp, ch & IN_CHAR);
len = 1;
}
if (ch & IN_EOF) while (len > 0) { (*tp->tty_echo)(tp, '\b'); len--; }
tp->tty_reprint = rp;
return(ch | (len << IN_LSHIFT));
}
/*===========================================================================*
* rawecho *
*===========================================================================*/
static void rawecho(tp, ch)
register tty_t *tp;
int ch;
{
/* Echo without interpretation if ECHO is set. */
int rp = tp->tty_reprint;
if (tp->tty_termios.c_lflag & ECHO) (*tp->tty_echo)(tp, ch);
tp->tty_reprint = rp;
}
/*===========================================================================*
* back_over *
*===========================================================================*/
static int back_over(tp)
register tty_t *tp;
{
/* Backspace to previous character on screen and erase it. */
u16_t *head;
int len;
if (tp->tty_incount == 0) return(0); /* queue empty */
head = tp->tty_inhead;
if (head == tp->tty_inbuf) head = bufend(tp->tty_inbuf);
if (*--head & IN_EOT) return(0); /* can't erase "line breaks" */
if (tp->tty_reprint) reprint(tp); /* reprint if messed up */
tp->tty_inhead = head;
tp->tty_incount--;
if (tp->tty_termios.c_lflag & ECHOE) {
len = (*head & IN_LEN) >> IN_LSHIFT;
while (len > 0) {
rawecho(tp, '\b');
rawecho(tp, ' ');
rawecho(tp, '\b');
len--;
}
}
return(1); /* one character erased */
}
/*===========================================================================*
* reprint *
*===========================================================================*/
static void reprint(tp)
register tty_t *tp; /* pointer to tty struct */
{
/* Restore what has been echoed to screen before if the user input has been
* messed up by output, or if REPRINT (^R) is typed.
*/
int count;
u16_t *head;
tp->tty_reprint = FALSE;
/* Find the last line break in the input. */
head = tp->tty_inhead;
count = tp->tty_incount;
while (count > 0) {
if (head == tp->tty_inbuf) head = bufend(tp->tty_inbuf);
if (head[-1] & IN_EOT) break;
head--;
count--;
}
if (count == tp->tty_incount) return; /* no reason to reprint */
/* Show REPRINT (^R) and move to a new line. */
(void) tty_echo(tp, tp->tty_termios.c_cc[VREPRINT] | IN_ESC);
rawecho(tp, '\r');
rawecho(tp, '\n');
/* Reprint from the last break onwards. */
do {
if (head == bufend(tp->tty_inbuf)) head = tp->tty_inbuf;
*head = tty_echo(tp, *head);
head++;
count++;
} while (count < tp->tty_incount);
}
/*===========================================================================*
* out_process *
*===========================================================================*/
void out_process(tp, bstart, bpos, bend, icount, ocount)
tty_t *tp;
char *bstart, *bpos, *bend; /* start/pos/end of circular buffer */
int *icount; /* # input chars / input chars used */
int *ocount; /* max output chars / output chars used */
{
/* Perform output processing on a circular buffer. *icount is the number of
* bytes to process, and the number of bytes actually processed on return.
* *ocount is the space available on input and the space used on output.
* (Naturally *icount < *ocount.) The column position is updated modulo
* the TAB size, because we really only need it for tabs.
*/
int tablen;
int ict = *icount;
int oct = *ocount;
int pos = tp->tty_position;
while (ict > 0) {
switch (*bpos) {
case '\7':
break;
case '\b':
pos--;
break;
case '\r':
pos = 0;
break;
case '\n':
if ((tp->tty_termios.c_oflag & (OPOST|ONLCR))
== (OPOST|ONLCR)) {
/* Map LF to CR+LF if there is space. Note that the
* next character in the buffer is overwritten, so
* we stop at this point.
*/
if (oct >= 2) {
*bpos = '\r';
if (++bpos == bend) bpos = bstart;
*bpos = '\n';
pos = 0;
ict--;
oct -= 2;
}
goto out_done; /* no space or buffer got changed */
}
break;
case '\t':
/* Best guess for the tab length. */
tablen = TAB_SIZE - (pos & TAB_MASK);
if ((tp->tty_termios.c_oflag & (OPOST|OXTABS))
== (OPOST|OXTABS)) {
/* Tabs must be expanded. */
if (oct >= tablen) {
pos += tablen;
ict--;
oct -= tablen;
do {
*bpos = ' ';
if (++bpos == bend) bpos = bstart;
} while (--tablen != 0);
}
goto out_done;
}
/* Tabs are output directly. */
pos += tablen;
break;
default:
/* Assume any other character prints as one character. */
pos++;
}
if (++bpos == bend) bpos = bstart;
ict--;
oct--;
}
out_done:
tp->tty_position = pos & TAB_MASK;
*icount -= ict; /* [io]ct are the number of chars not used */
*ocount -= oct; /* *[io]count are the number of chars that are used */
}
/*===========================================================================*
* dev_ioctl *
*===========================================================================*/
static void dev_ioctl(tp)
tty_t *tp;
{
/* The ioctl's TCSETSW, TCSETSF and TIOCDRAIN wait for output to finish to make
* sure that an attribute change doesn't affect the processing of current
* output. Once output finishes the ioctl is executed as in do_ioctl().
*/
int result = EINVAL;
if (tp->tty_outleft > 0) return; /* output not finished */
if (tp->tty_ioreq != TIOCDRAIN) {
if (tp->tty_ioreq == TIOCSETAF) tty_icancel(tp);
result = sys_safecopyfrom(tp->tty_iocaller, tp->tty_iogrant, 0,
(vir_bytes) &tp->tty_termios,
(vir_bytes) sizeof(tp->tty_termios));
if (result == OK) setattr(tp);
}
tp->tty_ioreq = 0;
chardriver_reply_task(tp->tty_iocaller, tp->tty_ioid, result);
tp->tty_iocaller = NONE;
}
/*===========================================================================*
* setattr *
*===========================================================================*/
static void setattr(tp)
tty_t *tp;
{
/* Apply the new line attributes (raw/canonical, line speed, etc.) */
u16_t *inp;
int count;
if (!(tp->tty_termios.c_lflag & ICANON)) {
/* Raw mode; put a "line break" on all characters in the input queue.
* It is undefined what happens to the input queue when ICANON is
* switched off, a process should use TCSAFLUSH to flush the queue.
* Keeping the queue to preserve typeahead is the Right Thing, however
* when a process does use TCSANOW to switch to raw mode.
*/
count = tp->tty_eotct = tp->tty_incount;
inp = tp->tty_intail;
while (count > 0) {
*inp |= IN_EOT;
if (++inp == bufend(tp->tty_inbuf)) inp = tp->tty_inbuf;
--count;
}
}
/* Inspect MIN and TIME. */
settimer(tp, FALSE);
if (tp->tty_termios.c_lflag & ICANON) {
/* No MIN & TIME in canonical mode. */
tp->tty_min = 1;
} else {
/* In raw mode MIN is the number of chars wanted, and TIME how long
* to wait for them. With interesting exceptions if either is zero.
*/
tp->tty_min = tp->tty_termios.c_cc[VMIN];
if (tp->tty_min == 0 && tp->tty_termios.c_cc[VTIME] > 0)
tp->tty_min = 1;
}
if (!(tp->tty_termios.c_iflag & IXON)) {
/* No start/stop output control, so don't leave output inhibited. */
tp->tty_inhibited = RUNNING;
tp->tty_events = 1;
}
/* Setting the output speed to zero hangs up the phone. */
if (tp->tty_termios.c_ospeed == B0) sigchar(tp, SIGHUP, 1);
/* Set new line speed, character size, etc at the device level. */
(*tp->tty_ioctl)(tp, 0);
}
/*===========================================================================*
* sigchar *
*===========================================================================*/
void sigchar(tp, sig, mayflush)
register tty_t *tp;
int sig; /* SIGINT, SIGQUIT, SIGKILL or SIGHUP */
int mayflush;
{
/* Process a SIGINT, SIGQUIT or SIGKILL char from the keyboard or SIGHUP from
* a tty close, "stty 0", or a real RS-232 hangup. PM will send the signal to
* the process group (INT, QUIT), all processes (KILL), or the session leader
* (HUP).
*/
int status;
if (tp->tty_pgrp != 0) {
if (OK != (status = sys_kill(tp->tty_pgrp, sig))) {
panic("Error; call to sys_kill failed: %d", status);
}
}
if (mayflush && !(tp->tty_termios.c_lflag & NOFLSH)) {
tp->tty_incount = tp->tty_eotct = 0; /* kill earlier input */
tp->tty_intail = tp->tty_inhead;
(*tp->tty_ocancel)(tp, 0); /* kill all output */
tp->tty_inhibited = RUNNING;
tp->tty_events = 1;
}
}
/*===========================================================================*
* tty_icancel *
*===========================================================================*/
static void tty_icancel(tp)
register tty_t *tp;
{
/* Discard all pending input, tty buffer or device. */
tp->tty_incount = tp->tty_eotct = 0;
tp->tty_intail = tp->tty_inhead;
(*tp->tty_icancel)(tp, 0);
}
/*===========================================================================*
* tty_devnop *
*===========================================================================*/
static int tty_devnop(tty_t *UNUSED(tp), int UNUSED(try))
{
/* Some functions need not be implemented at the device level. */
return 0;
}
/*===========================================================================*
* tty_init *
*===========================================================================*/
static void tty_init()
{
/* Initialize tty structure and call device initialization routines. */
register tty_t *tp;
int s;
system_hz = sys_hz();
/* Initialize the terminal lines. */
memset(tty_table, '\0' , sizeof(tty_table));
for (tp = FIRST_TTY,s=0; tp < END_TTY; tp++,s++) {
tp->tty_index = s;
init_timer(&tp->tty_tmr);
tp->tty_intail = tp->tty_inhead = tp->tty_inbuf;
tp->tty_min = 1;
tp->tty_incaller = tp->tty_outcaller = tp->tty_iocaller = NONE;
tp->tty_termios = termios_defaults;
tp->tty_icancel = tp->tty_ocancel = tp->tty_ioctl = tp->tty_close =
tp->tty_open = tty_devnop;
if (tp < tty_addr(NR_CONS)) {
scr_init(tp);
/* Initialize the keyboard driver. */
kb_init(tp);
tp->tty_minor = CONS_MINOR + s;
} else {
rs_init(tp);
tp->tty_minor = RS232_MINOR + s-NR_CONS;
}
}
}
/*===========================================================================*
* tty_timed_out *
*===========================================================================*/
static void tty_timed_out(minix_timer_t *tp)
{
/* This timer has expired. Set the events flag, to force processing. */
tty_t *tty_ptr;
tty_ptr = &tty_table[tmr_arg(tp)->ta_int];
tty_ptr->tty_min = 0; /* force read to succeed */
tty_ptr->tty_events = 1;
}
/*===========================================================================*
* settimer *
*===========================================================================*/
static void settimer(tty_ptr, enable)
tty_t *tty_ptr; /* line to set or unset a timer on */
int enable; /* set timer if true, otherwise unset */
{
clock_t ticks;
if (enable) {
ticks = tty_ptr->tty_termios.c_cc[VTIME] * (system_hz/10);
/* Set a new timer for enabling the TTY events flags. */
set_timer(&tty_ptr->tty_tmr, ticks, tty_timed_out, tty_ptr->tty_index);
} else {
/* Remove the timer from the active and expired lists. */
cancel_timer(&tty_ptr->tty_tmr);
}
}
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