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freebsd/sys/dev/snp/snp.c
Seigo Tanimura 512824f8f7 - Implement selwakeuppri() which allows raising the priority of a
thread being waken up.  The thread waken up can run at a priority as
  high as after tsleep().

- Replace selwakeup()s with selwakeuppri()s and pass appropriate
  priorities.

- Add cv_broadcastpri() which raises the priority of the broadcast
  threads.  Used by selwakeuppri() if collision occurs.

Not objected in:	-arch, -current
2003-11-09 09:17:26 +00:00

661 lines
14 KiB
C

/*
* Copyright (c) 1995 Ugen J.S.Antsilevich
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
* Obviously, it would be nice if you gave credit where credit is due
* but requiring it would be too onerous.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* Snoop stuff.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filio.h>
#include <sys/malloc.h>
#include <sys/tty.h>
#include <sys/conf.h>
#include <sys/poll.h>
#include <sys/kernel.h>
#include <sys/queue.h>
#include <sys/snoop.h>
#include <sys/vnode.h>
static l_close_t snplclose;
static l_write_t snplwrite;
static d_open_t snpopen;
static d_close_t snpclose;
static d_read_t snpread;
static d_write_t snpwrite;
static d_ioctl_t snpioctl;
static d_poll_t snppoll;
#define CDEV_MAJOR 53
static struct cdevsw snp_cdevsw = {
.d_open = snpopen,
.d_close = snpclose,
.d_read = snpread,
.d_write = snpwrite,
.d_ioctl = snpioctl,
.d_poll = snppoll,
.d_name = "snp",
.d_maj = CDEV_MAJOR,
};
static struct linesw snpdisc = {
ttyopen, snplclose, ttread, snplwrite,
l_nullioctl, ttyinput, ttstart, ttymodem
};
/*
* This is the main snoop per-device structure.
*/
struct snoop {
LIST_ENTRY(snoop) snp_list; /* List glue. */
int snp_unit; /* Device number. */
dev_t snp_target; /* Target tty device. */
struct tty *snp_tty; /* Target tty pointer. */
u_long snp_len; /* Possible length. */
u_long snp_base; /* Data base. */
u_long snp_blen; /* Used length. */
caddr_t snp_buf; /* Allocation pointer. */
int snp_flags; /* Flags. */
struct selinfo snp_sel; /* Select info. */
int snp_olddisc; /* Old line discipline. */
};
/*
* Possible flags.
*/
#define SNOOP_ASYNC 0x0002
#define SNOOP_OPEN 0x0004
#define SNOOP_RWAIT 0x0008
#define SNOOP_OFLOW 0x0010
#define SNOOP_DOWN 0x0020
/*
* Other constants.
*/
#define SNOOP_MINLEN (4*1024) /* This should be power of 2.
* 4K tested to be the minimum
* for which on normal tty
* usage there is no need to
* allocate more.
*/
#define SNOOP_MAXLEN (64*1024) /* This one also,64K enough
* If we grow more,something
* really bad in this world..
*/
static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data");
/*
* The number of the "snoop" line discipline. This gets determined at
* module load time.
*/
static int snooplinedisc;
static udev_t snpbasedev = NOUDEV;
static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist);
static struct tty *snpdevtotty(dev_t dev);
static void snp_clone(void *arg, char *name,
int namelen, dev_t *dev);
static int snp_detach(struct snoop *snp);
static int snp_down(struct snoop *snp);
static int snp_in(struct snoop *snp, char *buf, int n);
static int snp_modevent(module_t mod, int what, void *arg);
static int
snplclose(tp, flag)
struct tty *tp;
int flag;
{
struct snoop *snp;
int error;
snp = tp->t_sc;
error = snp_down(snp);
if (error != 0)
return (error);
error = ttylclose(tp, flag);
return (error);
}
static int
snplwrite(tp, uio, flag)
struct tty *tp;
struct uio *uio;
int flag;
{
struct iovec iov;
struct uio uio2;
struct snoop *snp;
int error, ilen;
char *ibuf;
error = 0;
ibuf = NULL;
snp = tp->t_sc;
while (uio->uio_resid > 0) {
ilen = imin(512, uio->uio_resid);
ibuf = malloc(ilen, M_SNP, M_WAITOK);
error = uiomove(ibuf, ilen, uio);
if (error != 0)
break;
snp_in(snp, ibuf, ilen);
/* Hackish, but probably the least of all evils. */
iov.iov_base = ibuf;
iov.iov_len = ilen;
uio2.uio_iov = &iov;
uio2.uio_iovcnt = 1;
uio2.uio_offset = 0;
uio2.uio_resid = ilen;
uio2.uio_segflg = UIO_SYSSPACE;
uio2.uio_rw = UIO_WRITE;
uio2.uio_td = uio->uio_td;
error = ttwrite(tp, &uio2, flag);
if (error != 0)
break;
free(ibuf, M_SNP);
ibuf = NULL;
}
if (ibuf != NULL)
free(ibuf, M_SNP);
return (error);
}
static struct tty *
snpdevtotty(dev)
dev_t dev;
{
struct cdevsw *cdp;
cdp = devsw(dev);
if (cdp == NULL || (cdp->d_flags & D_TTY) == 0)
return (NULL);
return (dev->si_tty);
}
#define SNP_INPUT_BUF 5 /* This is even too much, the maximal
* interactive mode write is 3 bytes
* length for function keys...
*/
static int
snpwrite(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
struct snoop *snp;
struct tty *tp;
int error, i, len;
unsigned char c[SNP_INPUT_BUF];
snp = dev->si_drv1;
tp = snp->snp_tty;
if (tp == NULL)
return (EIO);
if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) &&
tp->t_line == snooplinedisc)
goto tty_input;
printf("snp%d: attempt to write to bad tty\n", snp->snp_unit);
return (EIO);
tty_input:
if (!(tp->t_state & TS_ISOPEN))
return (EIO);
while (uio->uio_resid > 0) {
len = imin(uio->uio_resid, SNP_INPUT_BUF);
if ((error = uiomove(c, len, uio)) != 0)
return (error);
for (i=0; i < len; i++) {
if (ttyinput(c[i], tp))
return (EIO);
}
}
return (0);
}
static int
snpread(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
struct snoop *snp;
int error, len, n, nblen, s;
caddr_t from;
char *nbuf;
snp = dev->si_drv1;
KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen,
("snoop buffer error"));
if (snp->snp_tty == NULL)
return (EIO);
snp->snp_flags &= ~SNOOP_RWAIT;
do {
if (snp->snp_len == 0) {
if (flag & IO_NDELAY)
return (EWOULDBLOCK);
snp->snp_flags |= SNOOP_RWAIT;
error = tsleep(snp, (PZERO + 1) | PCATCH,
"snprd", 0);
if (error != 0)
return (error);
}
} while (snp->snp_len == 0);
n = snp->snp_len;
error = 0;
while (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) {
len = min((unsigned)uio->uio_resid, snp->snp_len);
from = (caddr_t)(snp->snp_buf + snp->snp_base);
if (len == 0)
break;
error = uiomove(from, len, uio);
snp->snp_base += len;
snp->snp_len -= len;
}
if ((snp->snp_flags & SNOOP_OFLOW) && (n < snp->snp_len)) {
snp->snp_flags &= ~SNOOP_OFLOW;
}
s = spltty();
nblen = snp->snp_blen;
if (((nblen / 2) >= SNOOP_MINLEN) && (nblen / 2) >= snp->snp_len) {
while (nblen / 2 >= snp->snp_len && nblen / 2 >= SNOOP_MINLEN)
nblen = nblen / 2;
if ((nbuf = malloc(nblen, M_SNP, M_NOWAIT)) != NULL) {
bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len);
free(snp->snp_buf, M_SNP);
snp->snp_buf = nbuf;
snp->snp_blen = nblen;
snp->snp_base = 0;
}
}
splx(s);
return (error);
}
static int
snp_in(snp, buf, n)
struct snoop *snp;
char *buf;
int n;
{
int s_free, s_tail;
int s, len, nblen;
caddr_t from, to;
char *nbuf;
KASSERT(n >= 0, ("negative snoop char count"));
if (n == 0)
return (0);
if (snp->snp_flags & SNOOP_DOWN) {
printf("snp%d: more data to down interface\n", snp->snp_unit);
return (0);
}
if (snp->snp_flags & SNOOP_OFLOW) {
printf("snp%d: buffer overflow\n", snp->snp_unit);
/*
* On overflow we just repeat the standart close
* procedure...yes , this is waste of space but.. Then next
* read from device will fail if one would recall he is
* snooping and retry...
*/
return (snp_down(snp));
}
s_tail = snp->snp_blen - (snp->snp_len + snp->snp_base);
s_free = snp->snp_blen - snp->snp_len;
if (n > s_free) {
s = spltty();
nblen = snp->snp_blen;
while ((n > s_free) && ((nblen * 2) <= SNOOP_MAXLEN)) {
nblen = snp->snp_blen * 2;
s_free = nblen - (snp->snp_len + snp->snp_base);
}
if ((n <= s_free) && (nbuf = malloc(nblen, M_SNP, M_NOWAIT))) {
bcopy(snp->snp_buf + snp->snp_base, nbuf, snp->snp_len);
free(snp->snp_buf, M_SNP);
snp->snp_buf = nbuf;
snp->snp_blen = nblen;
snp->snp_base = 0;
} else {
snp->snp_flags |= SNOOP_OFLOW;
if (snp->snp_flags & SNOOP_RWAIT) {
snp->snp_flags &= ~SNOOP_RWAIT;
wakeup(snp);
}
splx(s);
return (0);
}
splx(s);
}
if (n > s_tail) {
from = (caddr_t)(snp->snp_buf + snp->snp_base);
to = (caddr_t)(snp->snp_buf);
len = snp->snp_len;
bcopy(from, to, len);
snp->snp_base = 0;
}
to = (caddr_t)(snp->snp_buf + snp->snp_base + snp->snp_len);
bcopy(buf, to, n);
snp->snp_len += n;
if (snp->snp_flags & SNOOP_RWAIT) {
snp->snp_flags &= ~SNOOP_RWAIT;
wakeup(snp);
}
selwakeuppri(&snp->snp_sel, PZERO + 1);
return (n);
}
static int
snpopen(dev, flag, mode, td)
dev_t dev;
int flag, mode;
struct thread *td;
{
struct snoop *snp;
if (dev->si_drv1 == NULL) {
if (!(dev->si_flags & SI_NAMED))
make_dev(&snp_cdevsw, minor(dev), UID_ROOT, GID_WHEEL,
0600, "snp%d", dev2unit(dev));
dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP,
M_WAITOK | M_ZERO);
snp->snp_unit = dev2unit(dev);
} else
return (EBUSY);
/*
* We intentionally do not OR flags with SNOOP_OPEN, but set them so
* all previous settings (especially SNOOP_OFLOW) will be cleared.
*/
snp->snp_flags = SNOOP_OPEN;
snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK);
snp->snp_blen = SNOOP_MINLEN;
snp->snp_base = 0;
snp->snp_len = 0;
/*
* snp_tty == NULL is for inactive snoop devices.
*/
snp->snp_tty = NULL;
snp->snp_target = NODEV;
LIST_INSERT_HEAD(&snp_sclist, snp, snp_list);
return (0);
}
static int
snp_detach(snp)
struct snoop *snp;
{
struct tty *tp;
snp->snp_base = 0;
snp->snp_len = 0;
/*
* If line disc. changed we do not touch this pointer, SLIP/PPP will
* change it anyway.
*/
tp = snp->snp_tty;
if (tp == NULL)
goto detach_notty;
if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) &&
tp->t_line == snooplinedisc) {
tp->t_sc = NULL;
tp->t_state &= ~TS_SNOOP;
tp->t_line = snp->snp_olddisc;
} else
printf("snp%d: bad attached tty data\n", snp->snp_unit);
snp->snp_tty = NULL;
snp->snp_target = NODEV;
detach_notty:
selwakeuppri(&snp->snp_sel, PZERO + 1);
if ((snp->snp_flags & SNOOP_OPEN) == 0)
free(snp, M_SNP);
return (0);
}
static int
snpclose(dev, flags, fmt, td)
dev_t dev;
int flags;
int fmt;
struct thread *td;
{
struct snoop *snp;
snp = dev->si_drv1;
snp->snp_blen = 0;
LIST_REMOVE(snp, snp_list);
free(snp->snp_buf, M_SNP);
snp->snp_flags &= ~SNOOP_OPEN;
dev->si_drv1 = NULL;
return (snp_detach(snp));
}
static int
snp_down(snp)
struct snoop *snp;
{
if (snp->snp_blen != SNOOP_MINLEN) {
free(snp->snp_buf, M_SNP);
snp->snp_buf = malloc(SNOOP_MINLEN, M_SNP, M_WAITOK);
snp->snp_blen = SNOOP_MINLEN;
}
snp->snp_flags |= SNOOP_DOWN;
return (snp_detach(snp));
}
static int
snpioctl(dev, cmd, data, flags, td)
dev_t dev;
u_long cmd;
caddr_t data;
int flags;
struct thread *td;
{
struct snoop *snp;
struct tty *tp, *tpo;
dev_t tdev;
int s;
snp = dev->si_drv1;
switch (cmd) {
case SNPSTTY:
tdev = udev2dev(*((udev_t *)data), 0);
if (tdev == NODEV)
return (snp_down(snp));
tp = snpdevtotty(tdev);
if (!tp)
return (EINVAL);
if (tp->t_state & TS_SNOOP)
return (EBUSY);
s = spltty();
if (snp->snp_target == NODEV) {
tpo = snp->snp_tty;
if (tpo)
tpo->t_state &= ~TS_SNOOP;
}
tp->t_sc = (caddr_t)snp;
tp->t_state |= TS_SNOOP;
snp->snp_olddisc = tp->t_line;
tp->t_line = snooplinedisc;
snp->snp_tty = tp;
snp->snp_target = tdev;
/*
* Clean overflow and down flags -
* we'll have a chance to get them in the future :)))
*/
snp->snp_flags &= ~SNOOP_OFLOW;
snp->snp_flags &= ~SNOOP_DOWN;
splx(s);
break;
case SNPGTTY:
/*
* We keep snp_target field specially to make
* SNPGTTY happy, else we can't know what is device
* major/minor for tty.
*/
*((udev_t *)data) = dev2udev(snp->snp_target);
break;
case FIONBIO:
break;
case FIOASYNC:
if (*(int *)data)
snp->snp_flags |= SNOOP_ASYNC;
else
snp->snp_flags &= ~SNOOP_ASYNC;
break;
case FIONREAD:
s = spltty();
if (snp->snp_tty != NULL)
*(int *)data = snp->snp_len;
else
if (snp->snp_flags & SNOOP_DOWN) {
if (snp->snp_flags & SNOOP_OFLOW)
*(int *)data = SNP_OFLOW;
else
*(int *)data = SNP_TTYCLOSE;
} else {
*(int *)data = SNP_DETACH;
}
splx(s);
break;
default:
return (ENOTTY);
}
return (0);
}
static int
snppoll(dev, events, td)
dev_t dev;
int events;
struct thread *td;
{
struct snoop *snp;
int revents;
snp = dev->si_drv1;
revents = 0;
/*
* If snoop is down, we don't want to poll() forever so we return 1.
* Caller should see if we down via FIONREAD ioctl(). The last should
* return -1 to indicate down state.
*/
if (events & (POLLIN | POLLRDNORM)) {
if (snp->snp_flags & SNOOP_DOWN || snp->snp_len > 0)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(td, &snp->snp_sel);
}
return (revents);
}
static void
snp_clone(arg, name, namelen, dev)
void *arg;
char *name;
int namelen;
dev_t *dev;
{
int u;
if (*dev != NODEV)
return;
if (dev_stdclone(name, NULL, "snp", &u) != 1)
return;
*dev = make_dev(&snp_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600,
"snp%d", u);
if (snpbasedev == NOUDEV)
snpbasedev = (*dev)->si_udev;
else {
(*dev)->si_flags |= SI_CHEAPCLONE;
dev_depends(udev2dev(snpbasedev, 0), *dev);
}
}
static int
snp_modevent(mod, type, data)
module_t mod;
int type;
void *data;
{
static eventhandler_tag eh_tag;
switch (type) {
case MOD_LOAD:
/* XXX error checking. */
eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000);
snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc);
break;
case MOD_UNLOAD:
if (!LIST_EMPTY(&snp_sclist))
return (EBUSY);
EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
if (snpbasedev != NOUDEV)
destroy_dev(udev2dev(snpbasedev, 0));
ldisc_deregister(snooplinedisc);
break;
default:
break;
}
return (0);
}
static moduledata_t snp_mod = {
"snp",
snp_modevent,
NULL
};
DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR);