1 files changed, 150 insertions, 0 deletions
diff --git a/emu/port/devdup.c b/emu/port/devdup.c
new file mode 100644
index 00000000..7796a8f9
--- /dev/null
+++ b/emu/port/devdup.c
@@ -0,0 +1,150 @@
+#include	"dat.h"
+#include	"fns.h"
+#include	"error.h"
+#include	"interp.h"
+
+/* Qid is (2*fd + (file is ctl))+1 */
+
+static int
+dupgen(Chan *c, char *name, Dirtab *tab, int ntab, int s, Dir *dp)
+{
+	Fgrp *fgrp = up->env->fgrp;
+	Chan *f;
+	static int perm[] = { 0400, 0200, 0600, 0 };
+	int p;
+	Qid q;
+
+	USED(name); USED(tab); USED(ntab);
+	if(s == DEVDOTDOT){
+		devdir(c, c->qid, ".", 0, eve, DMDIR|0555, dp);
+		return 1;
+	}
+	if(s == 0)
+		return 0;
+	s--;
+	if(s/2 > fgrp->maxfd)
+		return -1;
+	if((f=fgrp->fd[s/2]) == nil)
+		return 0;
+	if(s & 1){
+		p = 0400;
+		sprint(up->genbuf, "%dctl", s/2);
+	}else{
+		p = perm[f->mode&3];
+		sprint(up->genbuf, "%d", s/2);
+	}
+	mkqid(&q, s+1, 0, QTFILE);
+	devdir(c, q, up->genbuf, 0, eve, p, dp);
+	return 1;
+}
+
+static Chan*
+dupattach(char *spec)
+{
+	return devattach('d', spec);
+}
+
+static Walkqid*
+dupwalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	return devwalk(c, nc, name, nname, nil, 0, dupgen);
+}
+
+static int
+dupstat(Chan *c, uchar *db, int n)
+{
+	return devstat(c, db, n, nil, 0, dupgen);
+}
+
+static Chan*
+dupopen(Chan *c, int omode)
+{
+	Chan *f;
+	int fd, twicefd;
+
+	if(c->qid.type & QTDIR){
+		if(omode != 0)
+			error(Eisdir);
+		c->mode = 0;
+		c->flag |= COPEN;
+		c->offset = 0;
+		return c;
+	}
+	if(c->qid.type & QTAUTH)
+		error(Eperm);
+	twicefd = c->qid.path - 1;
+	fd = twicefd/2;
+	if((twicefd & 1)){
+		/* ctl file */
+		f = c;
+		f->mode = openmode(omode);
+		f->flag |= COPEN;
+		f->offset = 0;
+	}else{
+		/* fd file */
+		f = fdtochan(up->env->fgrp, fd, openmode(omode), 0, 1);
+		cclose(c);
+	}
+	if(omode & OCEXEC)
+		f->flag |= CCEXEC;
+	return f;
+}
+
+static void
+dupclose(Chan *c)
+{
+	USED(c);
+}
+
+static long
+dupread(Chan *c, void *va, long n, vlong offset)
+{
+	char *a = va;
+	char buf[256];
+	int fd, twicefd;
+
+	if(c->qid.type == QTDIR)
+		return devdirread(c, a, n, nil, 0, dupgen);
+	twicefd = c->qid.path - 1;
+	fd = twicefd/2;
+	if(twicefd & 1){
+		c = fdtochan(up->env->fgrp, fd, -1, 0, 1);
+		if(waserror()){
+			cclose(c);
+			nexterror();
+		}
+		progfdprint(c, fd, 0, buf, sizeof buf);
+		poperror();
+		cclose(c);
+		return readstr((ulong)offset, va, n, buf);
+	}
+	panic("dupread");
+	return 0;
+}
+
+static long
+dupwrite(Chan *c, void *a, long n, vlong o)
+{
+	USED(c); USED(a); USED(n); USED(o);
+	panic("dupwrite");
+	return 0;		/* not reached */
+}
+
+Dev dupdevtab = {
+	'd',
+	"dup",
+
+	devinit,
+	dupattach,
+	dupwalk,
+	dupstat,
+	dupopen,
+	devcreate,
+	dupclose,
+	dupread,
+	devbread,
+	dupwrite,
+	devbwrite,
+	devremove,
+	devwstat,
+};