Date: Thu, 17 May 2001 22:17:26 -0700 From: Dima Dorfman <dima@unixfreak.org> To: audit@freebsd.org Subject: Patch to make snp(4) a module Message-ID: <20010518051726.D1FD83E0B@bazooka.unixfreak.org>
next in thread | raw e-mail | index | archive | help
Please review the attached patch to make snp(4) a module. Right now,
two things stop it from being one: it relies on hacks in the tty
subsystem which are compiled in just for it, and there is no kld code
in it.
The hacks in the tty subsystem look like this:
#ifdef DEV_SNP
if (ISSET(tp->t_state, TS_SNOOP) && tp->t_sc != NULL)
snpin((struct snoop *)tp->t_sc, cp, cc);
#endif
The patch solves this problem by using line disciplines to get the
information it needs. I don't know whether this is abuse or how bad
it is, but I sent this to -hackers a little while ago and no one
responsed (which means it's not interesting enough to say anything but
not ugly enough to warrant a bikeshed, either).
The second problem of not having kld code is solved in the obvious
manner (by adding the code).
Please review. Thanks in advance,
Dima Dorfman
dima@unixfreak.org
Index: kern/tty_snoop.c
===================================================================
RCS file: /st/src/FreeBSD/src/sys/kern/tty_snoop.c,v
retrieving revision 1.53
diff -u -r1.53 tty_snoop.c
--- kern/tty_snoop.c 2001/04/17 20:53:11 1.53
+++ kern/tty_snoop.c 2001/05/15 04:15:51
@@ -12,10 +12,9 @@
*
* Snoop stuff.
*
- * $FreeBSD: src/sys/kern/tty_snoop.c,v 1.53 2001/04/17 20:53:11 dd Exp $
+ * $FreeBSD$
*/
-#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filio.h>
@@ -29,6 +28,7 @@
#include <sys/kernel.h>
#include <sys/snoop.h>
#include <sys/vnode.h>
+#include <sys/conf.h>
static d_open_t snpopen;
static d_close_t snpclose;
@@ -61,9 +61,63 @@
static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data");
+#define ttytosnp(t) (struct snoop *)(t)->t_sc
static struct tty *snpdevtotty __P((dev_t dev));
static int snp_detach __P((struct snoop *snp));
+/*
+ * The number of the "snoop" line discipline. This gets determined at
+ * module load time.
+ */
+static int mylinedisc;
+
+static int
+dsnwrite(struct tty *tp, struct uio *uio, int flag)
+{
+ struct snoop *snp = ttytosnp(tp);
+ int error = 0;
+ char ibuf[1024];
+ int ilen;
+ struct iovec iov;
+ struct uio uio2;
+
+ while (uio->uio_resid) {
+ ilen = MIN(sizeof(ibuf), uio->uio_resid);
+ error = uiomove(ibuf, ilen, uio);
+ if (error)
+ break;
+ snpin(snp, ibuf, ilen);
+ /* Hackish, but I think it's 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_procp = uio->uio_procp;
+ error = ttwrite(tp, &uio2, flag);
+ if (error)
+ break;
+ }
+ return (error);
+}
+
+/*
+ * XXX should there be a global version of this?
+ */
+static int
+l_nullioctl(struct tty *tp, u_long cmd, char *data, int flags, struct proc *p)
+{
+
+ return (ENOIOCTL);
+}
+
+static struct linesw snpdisc = {
+ ttyopen, ttylclose, ttread, dsnwrite,
+ l_nullioctl, ttyinput, ttstart, ttymodem };
+
static struct tty *
snpdevtotty (dev)
dev_t dev;
@@ -98,7 +152,7 @@
tp = snp->snp_tty;
if ((tp->t_sc == snp) && (tp->t_state & TS_SNOOP) &&
- (tp->t_line == OTTYDISC || tp->t_line == NTTYDISC))
+ tp->t_line == mylinedisc)
goto tty_input;
printf("Snoop: attempt to write to bad tty.\n");
@@ -334,9 +388,10 @@
tp = snp->snp_tty;
if (tp && (tp->t_sc == snp) && (tp->t_state & TS_SNOOP) &&
- (tp->t_line == OTTYDISC || tp->t_line == NTTYDISC)) {
+ tp->t_line == mylinedisc) {
tp->t_sc = NULL;
tp->t_state &= ~TS_SNOOP;
+ tp->t_line = snp->snp_olddisc;
} else
printf("Snoop: bad attached tty data.\n");
@@ -409,12 +464,6 @@
if (!tp)
return (EINVAL);
- if ((tp->t_sc != (caddr_t)snp) && (tp->t_state & TS_SNOOP))
- return (EBUSY);
-
- if ((tp->t_line != OTTYDISC) && (tp->t_line != NTTYDISC))
- return (EBUSY);
-
s = spltty();
if (snp->snp_target == NODEV) {
@@ -425,6 +474,8 @@
tp->t_sc = (caddr_t)snp;
tp->t_state |= TS_SNOOP;
+ snp->snp_olddisc = tp->t_line;
+ tp->t_line = mylinedisc;
snp->snp_tty = tp;
snp->snp_target = tdev;
@@ -503,8 +554,6 @@
return (revents);
}
-static void snp_drvinit __P((void *unused));
-
static void
snp_clone(void *arg, char *name, int namelen, dev_t *dev)
{
@@ -519,13 +568,31 @@
return;
}
-static void
-snp_drvinit(unused)
- void *unused;
+static int
+snp_modevent(module_t mod, int type, void *data)
{
+ static eventhandler_tag eh_tag = NULL;
- EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000);
- cdevsw_add(&snp_cdevsw);
+ switch (type) {
+ case MOD_LOAD:
+ eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000);
+ mylinedisc = ldisc_register(LDISC_LOAD, &snpdisc);
+ cdevsw_add(&snp_cdevsw);
+ break;
+ case MOD_UNLOAD:
+ EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
+ ldisc_deregister(mylinedisc);
+ cdevsw_remove(&snp_cdevsw);
+ break;
+ default:
+ break;
+ }
+ return 0;
}
-SYSINIT(snpdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,snp_drvinit,NULL)
+static moduledata_t snp_mod = {
+ "snp",
+ snp_modevent,
+ NULL
+};
+DECLARE_MODULE(snp, snp_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE+CDEV_MAJOR);
Index: sys/snoop.h
===================================================================
RCS file: /st/src/FreeBSD/src/sys/sys/snoop.h,v
retrieving revision 1.14
diff -u -r1.14 snoop.h
--- sys/snoop.h 1999/12/29 04:24:47 1.14
+++ sys/snoop.h 2001/05/15 04:15:51
@@ -54,6 +54,7 @@
#define SNOOP_OFLOW 0x0010
#define SNOOP_DOWN 0x0020
struct selinfo snp_sel; /* Selection info */
+ int snp_olddisc; /* Old line discipline */
};
/* XXX several wrong storage classes and types here. */
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-audit" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010518051726.D1FD83E0B>