minix/drivers/tty/pty.c
Thomas Veerman b01e9ebfdb TTY: seperate hardware dependent parts + add new serial driver
.Split TTY in order to support both x86 and ARM.
.Add support for the TI 16750 UARTs on OMAP35x.
.Various other improvements:
  .Kernel messages are printed using generic terminal write
   functions. That is, they are no longer directly displayed
   on the console.
  .The console can now be displayed on any terminal. This
   is configured by the "console={tty00,tty01,ttyc2,ttyc3,ttyc4}"
   boot variable -- basically any valid /dev/tty* terminal.
  .Cutify kernel messages with colors. Configured by
   "kernelclr={1,2,3,4,5,6,7}" boot variable.
2012-10-30 11:33:29 +00:00

625 lines
16 KiB
C

/* pty.c - pseudo terminal driver Author: Kees J. Bot
* 30 Dec 1995
* PTYs can be seen as a bidirectional pipe with TTY
* input and output processing. For example a simple rlogin session:
*
* keyboard -> rlogin -> in.rld -> /dev/ptypX -> /dev/ttypX -> shell
* shell -> /dev/ttypX -> /dev/ptypX -> in.rld -> rlogin -> screen
*
* This file takes care of copying data between the tty/pty device pairs and
* the open/read/write/close calls on the pty devices. The TTY task takes
* care of the input and output processing (interrupt, backspace, raw I/O,
* etc.) using the pty_read() and pty_write() functions as the "keyboard" and
* "screen" functions of the ttypX devices.
* Be careful when reading this code, the terms "reading" and "writing" are
* used both for the tty and the pty end of the pseudo tty. Writes to one
* end are to be read at the other end and vice-versa.
*/
#include <minix/drivers.h>
#include <assert.h>
#include <termios.h>
#include <signal.h>
#include <minix/com.h>
#include <minix/callnr.h>
#include <sys/select.h>
#include "tty.h"
#if NR_PTYS > 0
/* PTY bookkeeping structure, one per pty/tty pair. */
typedef struct pty {
tty_t *tty; /* associated TTY structure */
char state; /* flags: busy, closed, ... */
/* Read call on /dev/ptypX. */
char rdsendreply; /* send a reply (instead of notify) */
int rdcaller; /* process making the call (usually FS) */
int rdproc; /* process that wants to read from the pty */
cp_grant_id_t rdgrant; /* grant for readers address space */
vir_bytes rdoffset; /* offset in above grant */
int rdleft; /* # bytes yet to be read */
int rdcum; /* # bytes written so far */
/* Write call to /dev/ptypX. */
char wrsendreply; /* send a reply (instead of notify) */
int wrcaller; /* process making the call (usually FS) */
int wrproc; /* process that wants to write to the pty */
cp_grant_id_t wrgrant; /* grant for writers address space */
vir_bytes wroffset; /* offset in above grant */
int wrleft; /* # bytes yet to be written */
int wrcum; /* # bytes written so far */
/* Output buffer. */
int ocount; /* # characters in the buffer */
char *ohead, *otail; /* head and tail of the circular buffer */
char obuf[2048]; /* buffer for bytes going to the pty reader */
/* select() data. */
int select_ops, /* Which operations do we want to know about? */
select_proc, /* Who wants to know about it? */
select_ready_ops; /* For callback. */
} pty_t;
#define PTY_ACTIVE 0x01 /* pty is open/active */
#define TTY_CLOSED 0x02 /* tty side has closed down */
#define PTY_CLOSED 0x04 /* pty side has closed down */
static pty_t pty_table[NR_PTYS]; /* PTY bookkeeping */
static int pty_write(tty_t *tp, int try);
static void pty_echo(tty_t *tp, int c);
static void pty_start(pty_t *pp);
static void pty_finish(pty_t *pp);
static int pty_read(tty_t *tp, int try);
static int pty_close(tty_t *tp, int try);
static int pty_icancel(tty_t *tp, int try);
static int pty_ocancel(tty_t *tp, int try);
static int pty_select(tty_t *tp, message *m);
/*===========================================================================*
* do_pty *
*===========================================================================*/
void do_pty(tty_t *tp, message *m_ptr)
{
/* Perform an open/close/read/write call on a /dev/ptypX device. */
pty_t *pp = tp->tty_priv;
int r;
switch (m_ptr->m_type) {
case DEV_READ_S:
/* Check, store information on the reader, do I/O. */
if (pp->state & TTY_CLOSED) {
r = 0;
break;
}
if (pp->rdleft != 0 || pp->rdcum != 0) {
r = EIO;
break;
}
if (m_ptr->COUNT <= 0) {
r = EINVAL;
break;
}
if (pp->rdgrant != GRANT_INVALID) {
r = ENOBUFS;
break;
}
pp->rdsendreply = TRUE;
pp->rdcaller = m_ptr->m_source;
pp->rdproc = m_ptr->USER_ENDPT;
pp->rdgrant = (cp_grant_id_t) m_ptr->IO_GRANT;
pp->rdoffset = 0;
pp->rdleft = m_ptr->COUNT;
pty_start(pp);
handle_events(tp);
if (pp->rdleft == 0) {
pp->rdgrant = GRANT_INVALID;
return; /* already done */
}
{
r = SUSPEND; /* do suspend */
pp->rdsendreply = FALSE;
}
break;
case DEV_WRITE_S:
/* Check, store information on the writer, do I/O. */
if (pp->state & TTY_CLOSED) {
r = EIO;
break;
}
if (pp->wrleft != 0 || pp->wrcum != 0) {
r = EIO;
break;
}
if (m_ptr->COUNT <= 0) {
r = EINVAL;
break;
}
if (pp->wrgrant != GRANT_INVALID) {
r = ENOBUFS;
break;
}
pp->wrsendreply = TRUE;
pp->wrcaller = m_ptr->m_source;
pp->wrproc = m_ptr->USER_ENDPT;
pp->wrgrant = (cp_grant_id_t) m_ptr->IO_GRANT;
pp->wroffset = 0;
pp->wrleft = m_ptr->COUNT;
handle_events(tp);
if (pp->wrleft == 0) {
pp->wrgrant = GRANT_INVALID;
return; /* already done */
}
{
pp->wrsendreply = FALSE; /* do suspend */
r = SUSPEND;
}
break;
case DEV_OPEN:
r = pp->state != 0 ? EIO : OK;
pp->state |= PTY_ACTIVE;
pp->rdcum = 0;
pp->wrcum = 0;
break;
case DEV_CLOSE:
r = OK;
if (pp->state & TTY_CLOSED) {
pp->state = 0;
} else {
pp->state |= PTY_CLOSED;
sigchar(tp, SIGHUP, 1);
}
break;
case DEV_SELECT:
r = pty_select(tp, m_ptr);
break;
case CANCEL:
r = EINTR;
if (m_ptr->USER_ENDPT == pp->rdproc) {
/* Cancel a read from a PTY. */
r = pp->rdcum > 0 ? pp->rdcum : EAGAIN;
pp->rdleft = pp->rdcum = 0;
pp->rdgrant = GRANT_INVALID;
}
if (m_ptr->USER_ENDPT == pp->wrproc) {
/* Cancel a write to a PTY. */
r = pp->wrcum > 0 ? pp->wrcum : EAGAIN;
pp->wrleft = pp->wrcum = 0;
pp->wrgrant = GRANT_INVALID;
}
break;
default:
r = EINVAL;
}
tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->USER_ENDPT, r);
}
/*===========================================================================*
* pty_write *
*===========================================================================*/
static int pty_write(tty_t *tp, int try)
{
/* (*dev_write)() routine for PTYs. Transfer bytes from the writer on
* /dev/ttypX to the output buffer.
*/
pty_t *pp = tp->tty_priv;
int count, ocount, s;
/* PTY closed down? */
if (pp->state & PTY_CLOSED) {
if (try) return 1;
if (tp->tty_outleft > 0) {
if(tp->tty_outrepcode == TTY_REVIVE) {
notify(tp->tty_outcaller);
tp->tty_outrevived = 1;
} else {
tty_reply(tp->tty_outrepcode, tp->tty_outcaller,
tp->tty_outproc, EIO);
tp->tty_outleft = tp->tty_outcum = 0;
}
}
return 0;
}
/* While there is something to do. */
for (;;) {
ocount = buflen(pp->obuf) - pp->ocount;
if (try) return (ocount > 0);
count = bufend(pp->obuf) - pp->ohead;
if (count > ocount) count = ocount;
if (count > tp->tty_outleft) count = tp->tty_outleft;
if (count == 0 || tp->tty_inhibited)
break;
/* Copy from user space to the PTY output buffer. */
if (tp->tty_outcaller == KERNEL) {
/* We're trying to print on kernel's behalf */
memcpy(pp->ohead, (void *) tp->tty_outgrant + tp->tty_outoffset,
count);
} else {
if ((s = sys_safecopyfrom(tp->tty_outcaller, tp->tty_outgrant,
tp->tty_outoffset, (vir_bytes) pp->ohead,
count)) != OK) {
break;
}
}
/* Perform output processing on the output buffer. */
out_process(tp, pp->obuf, pp->ohead, bufend(pp->obuf), &count, &ocount);
if (count == 0) break;
/* Assume echoing messed up by output. */
tp->tty_reprint = TRUE;
/* Bookkeeping. */
pp->ocount += ocount;
if ((pp->ohead += ocount) >= bufend(pp->obuf))
pp->ohead -= buflen(pp->obuf);
pty_start(pp);
tp->tty_outoffset += count;
tp->tty_outcum += count;
if ((tp->tty_outleft -= count) == 0) {
/* Output is finished, reply to the writer. */
if(tp->tty_outrepcode == TTY_REVIVE) {
notify(tp->tty_outcaller);
tp->tty_outrevived = 1;
} else {
tty_reply(tp->tty_outrepcode, tp->tty_outcaller,
tp->tty_outproc, tp->tty_outcum);
tp->tty_outcum = 0;
}
}
}
pty_finish(pp);
return 1;
}
/*===========================================================================*
* pty_echo *
*===========================================================================*/
static void pty_echo(tty_t *tp, int c)
{
/* Echo one character. (Like pty_write, but only one character, optionally.) */
pty_t *pp = tp->tty_priv;
int count, ocount;
ocount = buflen(pp->obuf) - pp->ocount;
if (ocount == 0) return; /* output buffer full */
count = 1;
*pp->ohead = c; /* add one character */
out_process(tp, pp->obuf, pp->ohead, bufend(pp->obuf), &count, &ocount);
if (count == 0) return;
pp->ocount += ocount;
if ((pp->ohead += ocount) >= bufend(pp->obuf)) pp->ohead -= buflen(pp->obuf);
pty_start(pp);
}
/*===========================================================================*
* pty_start *
*===========================================================================*/
static void pty_start(pty_t *pp)
{
/* Transfer bytes written to the output buffer to the PTY reader. */
int count;
/* While there are things to do. */
for (;;) {
int s;
count = bufend(pp->obuf) - pp->otail;
if (count > pp->ocount) count = pp->ocount;
if (count > pp->rdleft) count = pp->rdleft;
if (count == 0) break;
/* Copy from the output buffer to the readers address space. */
if((s = sys_safecopyto(pp->rdcaller, pp->rdgrant,
pp->rdoffset, (vir_bytes) pp->otail, count)) != OK) {
break;
}
pp->rdoffset += count;
/* Bookkeeping. */
pp->ocount -= count;
if ((pp->otail += count) == bufend(pp->obuf)) pp->otail = pp->obuf;
pp->rdcum += count;
pp->rdleft -= count;
}
}
/*===========================================================================*
* pty_finish *
*===========================================================================*/
static void pty_finish(pty_t *pp)
{
/* Finish the read request of a PTY reader if there is at least one byte
* transferred.
*/
if (pp->rdcum > 0) {
if (pp->rdsendreply) {
tty_reply(TASK_REPLY, pp->rdcaller, pp->rdproc, pp->rdcum);
pp->rdleft = pp->rdcum = 0;
}
else
notify(pp->rdcaller);
}
}
/*===========================================================================*
* pty_read *
*===========================================================================*/
static int pty_read(tty_t *tp, int try)
{
/* Offer bytes from the PTY writer for input on the TTY. (Do it one byte at
* a time, 99% of the writes will be for one byte, so no sense in being smart.)
*/
pty_t *pp = tp->tty_priv;
char c;
if (pp->state & PTY_CLOSED) {
if (try) return 1;
if (tp->tty_inleft > 0) {
if(tp->tty_inrepcode == TTY_REVIVE) {
notify(tp->tty_incaller);
tp->tty_inrevived = 1;
} else {
tty_reply(tp->tty_inrepcode, tp->tty_incaller,
tp->tty_inproc, tp->tty_incum);
tp->tty_inleft = tp->tty_incum = 0;
}
}
return 1;
}
if (try) {
if (pp->wrleft > 0)
return 1;
return 0;
}
while (pp->wrleft > 0) {
int s;
/* Transfer one character to 'c'. */
if ((s = sys_safecopyfrom(pp->wrcaller, pp->wrgrant, pp->wroffset,
(vir_bytes) &c, 1)) != OK) {
printf("pty: safecopy failed (error %d)\n", s);
break;
}
pp->wroffset++;
/* Input processing. */
if (in_process(tp, &c, 1, -1) == 0) break;
/* PTY writer bookkeeping. */
pp->wrcum++;
if (--pp->wrleft == 0) {
if (pp->wrsendreply) {
tty_reply(TASK_REPLY, pp->wrcaller, pp->wrproc,
pp->wrcum);
pp->wrcum = 0;
}
else
notify(pp->wrcaller);
}
}
return 0;
}
/*===========================================================================*
* pty_close *
*===========================================================================*/
static int pty_close(tty_t *tp, int UNUSED(try))
{
/* The tty side has closed, so shut down the pty side. */
pty_t *pp = tp->tty_priv;
if (!(pp->state & PTY_ACTIVE)) return 0;
if (pp->rdleft > 0) {
assert(!pp->rdsendreply);
notify(pp->rdcaller);
}
if (pp->wrleft > 0) {
assert(!pp->wrsendreply);
notify(pp->wrcaller);
}
if (pp->state & PTY_CLOSED) pp->state = 0; else pp->state |= TTY_CLOSED;
return 0;
}
/*===========================================================================*
* pty_icancel *
*===========================================================================*/
static int pty_icancel(tty_t *tp, int UNUSED(try))
{
/* Discard waiting input. */
pty_t *pp = tp->tty_priv;
if (pp->wrleft > 0) {
pp->wrcum += pp->wrleft;
pp->wrleft= 0;
notify(pp->wrcaller);
}
return 0;
}
/*===========================================================================*
* pty_ocancel *
*===========================================================================*/
static int pty_ocancel(tty_t *tp, int UNUSED(try))
{
/* Drain the output buffer. */
pty_t *pp = tp->tty_priv;
pp->ocount = 0;
pp->otail = pp->ohead;
return 0;
}
/*===========================================================================*
* pty_init *
*===========================================================================*/
void pty_init(tty_t *tp)
{
pty_t *pp;
int line;
/* Associate PTY and TTY structures. */
line = tp - &tty_table[NR_CONS + NR_RS_LINES];
pp = tp->tty_priv = &pty_table[line];
pp->tty = tp;
pp->select_ops = 0;
pp->rdgrant = GRANT_INVALID;
pp->wrgrant = GRANT_INVALID;
/* Set up output queue. */
pp->ohead = pp->otail = pp->obuf;
/* Fill in TTY function hooks. */
tp->tty_devread = pty_read;
tp->tty_devwrite = pty_write;
tp->tty_echo = pty_echo;
tp->tty_icancel = pty_icancel;
tp->tty_ocancel = pty_ocancel;
tp->tty_close = pty_close;
tp->tty_select_ops = 0;
}
/*===========================================================================*
* pty_status *
*===========================================================================*/
int pty_status(message *m_ptr)
{
int i, event_found;
pty_t *pp;
event_found = 0;
for (i= 0, pp = pty_table; i<NR_PTYS; i++, pp++) {
if ((((pp->state & TTY_CLOSED) && pp->rdleft > 0) ||
pp->rdcum > 0) &&
pp->rdcaller == m_ptr->m_source)
{
m_ptr->m_type = DEV_REVIVE;
m_ptr->REP_ENDPT = pp->rdproc;
m_ptr->REP_IO_GRANT = pp->rdgrant;
m_ptr->REP_STATUS = pp->rdcum;
pp->rdleft = pp->rdcum = 0;
pp->rdgrant = GRANT_INVALID;
event_found = 1;
break;
}
if ((((pp->state & TTY_CLOSED) && pp->wrleft > 0) ||
pp->wrcum > 0) &&
pp->wrcaller == m_ptr->m_source)
{
m_ptr->m_type = DEV_REVIVE;
m_ptr->REP_ENDPT = pp->wrproc;
m_ptr->REP_IO_GRANT = pp->wrgrant;
if (pp->wrcum == 0)
m_ptr->REP_STATUS = EIO;
else
m_ptr->REP_STATUS = pp->wrcum;
pp->wrleft = pp->wrcum = 0;
pp->wrgrant = GRANT_INVALID;
event_found = 1;
break;
}
if (pp->select_ready_ops && pp->select_proc == m_ptr->m_source) {
m_ptr->m_type = DEV_IO_READY;
m_ptr->DEV_MINOR = PTYPX_MINOR + i;
m_ptr->DEV_SEL_OPS = pp->select_ready_ops;
pp->select_ready_ops = 0;
event_found = 1;
break;
}
}
return event_found;
}
/*===========================================================================*
* select_try_pty *
*===========================================================================*/
static int select_try_pty(tty_t *tp, int ops)
{
pty_t *pp = tp->tty_priv;
int r = 0;
if (ops & SEL_WR) {
/* Write won't block on error. */
if (pp->state & TTY_CLOSED) r |= SEL_WR;
else if (pp->wrleft != 0 || pp->wrcum != 0) r |= SEL_WR;
else r |= SEL_WR;
}
if (ops & SEL_RD) {
/* Read won't block on error. */
if (pp->state & TTY_CLOSED) r |= SEL_RD;
else if (pp->rdleft != 0 || pp->rdcum != 0) r |= SEL_RD;
else if (pp->ocount > 0) r |= SEL_RD; /* Actual data. */
}
return r;
}
/*===========================================================================*
* select_retry_pty *
*===========================================================================*/
void select_retry_pty(tty_t *tp)
{
pty_t *pp = tp->tty_priv;
int r;
/* See if the pty side of a pty is ready to return a select. */
if (pp->select_ops && (r=select_try_pty(tp, pp->select_ops))) {
pp->select_ops &= ~r;
pp->select_ready_ops |= r;
notify(pp->select_proc);
}
}
/*===========================================================================*
* pty_select *
*===========================================================================*/
static int pty_select(tty_t *tp, message *m)
{
pty_t *pp = tp->tty_priv;
int ops, ready_ops = 0, watch;
ops = m->USER_ENDPT & (SEL_RD|SEL_WR|SEL_ERR);
watch = (m->USER_ENDPT & SEL_NOTIFY) ? 1 : 0;
ready_ops = select_try_pty(tp, ops);
if (!ready_ops && ops && watch) {
pp->select_ops |= ops;
pp->select_proc = m->m_source;
}
return ready_ops;
}
#endif /* NR_PTYS > 0 */