20060303

1 files changed, 248 insertions, 0 deletions

diff --git a/os/port/devcap.c b/os/port/devcap.c
new file mode 100644
index 00000000..64232c57
--- /dev/null
+++ b/os/port/devcap.c
@@ -0,0 +1,248 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"error.h"
+#include	"mp.h"
+#include	"libsec.h"
+
+/*
+ * Copyright © 2003 Vita Nuova Holdings Limited.  All rights reserved.
+ */
+
+enum {
+	Captimeout = 15,	/* seconds until expiry */
+	Capidletime = 60	/* idle seconds before capwatch exits */
+};
+
+typedef struct Caps Caps;
+struct Caps
+{
+	uchar	hash[SHA1dlen];
+	ulong	time;
+	Caps*	next;
+};
+
+struct {
+	QLock	l;
+	Caps*	caps;
+	int	kpstarted;
+} allcaps;
+
+enum {
+	Qdir,
+	Qhash,
+	Quse
+};
+
+static Dirtab capdir[] =
+{
+	".",			{Qdir, 0, QTDIR},	0,	DMDIR|0555,
+	"capuse",		{Quse, 0},			0,	0222,
+	"caphash",	{Qhash, 0},		0,	0200,
+};
+
+static int ncapdir = nelem(capdir);
+
+static void
+capwatch(void *a)
+{
+	Caps *c, **l;
+	int idletime;
+
+	USED(a);
+	idletime = 0;
+	for(;;){
+		tsleep(&up->sleep, return0, nil, 30*1000);
+		qlock(&allcaps.l);
+		for(l = &allcaps.caps; (c = *l) != nil;)
+			if(++c->time > Captimeout){
+				*l = c->next;
+				free(c);
+			}else
+				l = &c->next;
+		if(allcaps.caps == nil){
+			if(++idletime > Capidletime){
+				allcaps.kpstarted = 0;
+				qunlock(&allcaps.l);
+				pexit("", 0);
+			}
+		}else
+			idletime = 0;
+		qunlock(&allcaps.l);
+	}
+}
+
+static Chan *
+capattach(char *spec)
+{
+	return devattach(L'¤', spec);
+}
+
+static Walkqid*
+capwalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	return devwalk(c, nc, name, nname, capdir, nelem(capdir), devgen);
+}
+
+static int
+capstat(Chan *c, uchar *db, int n)
+{
+	return devstat(c, db, n, capdir, nelem(capdir), devgen);
+}
+
+static Chan*
+capopen(Chan *c, int omode)
+{
+	if(c->qid.type & QTDIR) {
+		if(omode != OREAD)
+			error(Eisdir);
+		c->mode = omode;
+		c->flag |= COPEN;
+		c->offset = 0;
+		return c;
+	}
+
+	if(c->qid.path == Qhash && !iseve())
+		error(Eperm);
+
+	c->mode = openmode(omode);
+	c->flag |= COPEN;
+	c->offset = 0;
+	return c;
+}
+
+static void
+capclose(Chan *c)
+{
+	USED(c);
+}
+
+static long
+capread(Chan *c, void *va, long n, vlong vl)
+{
+	USED(vl);
+	switch((ulong)c->qid.path){
+	case Qdir:
+		return devdirread(c, va, n, capdir, ncapdir, devgen);
+
+	default:
+		error(Eperm);
+		break;
+	}
+	return n;
+}
+
+static int
+capwritehash(uchar *a, int l)
+{
+	Caps *c;
+
+	if(l != SHA1dlen)
+		return -1;
+	c = malloc(sizeof(*c));
+	if(c == nil)
+		return -1;
+	memmove(c->hash, a, l);
+	c->time = 0;
+	qlock(&allcaps.l);
+	c->next = allcaps.caps;
+	allcaps.caps = c;
+	if(!allcaps.kpstarted){
+		allcaps.kpstarted = 1;
+		kproc("capwatch", capwatch, 0, 0);
+	}
+	qunlock(&allcaps.l);
+	return 0;
+}
+
+static int
+capwriteuse(uchar *a, int len)
+{
+	int n;
+	uchar digest[SHA1dlen];
+	char buf[128], *p, *users[3];
+	Caps *c, **l;
+
+	if(len >= sizeof(buf)-1)
+		return -1;
+	memmove(buf, a, len);
+	buf[len] = 0;
+	p = strrchr(buf, '@');
+	if(p == nil)
+		return -1;
+	*p++ = 0;
+	len = strlen(p);
+	n = strlen(buf);
+	if(len == 0 || n == 0)
+		return -1;
+	hmac_sha1((uchar*)buf, n, (uchar*)p, len, digest, nil);
+	n = getfields(buf, users, nelem(users), 0, "@");
+	if(n == 1)
+		users[1] = users[0];
+	else if(n != 2)
+		return -1;
+	if(*users[0] == 0 || *users[1] == 0)
+		return -1;
+	qlock(&allcaps.l);
+	for(l = &allcaps.caps; (c = *l) != nil; l = &c->next)
+		if(memcmp(c->hash, digest, sizeof(c->hash)) == 0){
+			*l = c->next;
+			qunlock(&allcaps.l);
+			free(c);
+			if(n == 2 && strcmp(up->env->user, users[0]) != 0)
+				return -1;
+			kstrdup(&up->env->user, users[1]);
+			return 0;
+		}
+	qunlock(&allcaps.l);
+	return -1;
+}
+
+static long	 
+capwrite(Chan* c, void* buf, long n, vlong offset)
+{
+	USED(offset);
+	switch((ulong)c->qid.path){
+	case Qhash:
+		if(capwritehash(buf, n) < 0)
+			error(Ebadarg);
+		return n;
+	case Quse:
+		if(capwriteuse(buf, n) < 0)
+			error("invalid capability");
+		return n;
+	}
+	error(Ebadarg);
+	return 0;
+}
+
+static void
+capremove(Chan *c)
+{
+	if(c->qid.path != Qhash || !iseve())
+		error(Eperm);
+	ncapdir = nelem(capdir)-1;
+}
+
+Dev capdevtab = {
+	L'¤',
+	"cap",
+
+	devreset,
+	devinit,
+	devshutdown,
+	capattach,
+	capwalk,
+	capstat,
+	capopen,
+	devcreate,
+	capclose,
+	capread,
+	devbread,
+	capwrite,
+	devbwrite,
+	capremove,
+	devwstat
+};