code: 9ferno

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fix bug in direntry mode conversion

Dir.mode is a u32
Sys_dir.mode is a WORD

When converting a ~0 value from Dir.mode to Sys_dir.mode, it is not
sign extended.

The default value for Dir.mode (specified by nulldir) is ~0.

When checking for mode's default value in Sys_dir, it should be checked
for 16rFFFFFFFF along with ~0.

--- a/appl/cmd/disk/kfs.b

+++ b/appl/cmd/disk/kfs.b

@@ -1787,8 +1787,10 @@

 	# 'type' or'ed with the old directory mode;

 	# else neither are defaults, use the new mode but check

 	# it agrees with 'type'.

-

-	if(dir.qid.qtype == 16rFF && dir.mode == ~0){

+	# checking for the default value of 16rFFFFFFFF also as the

+	# conversion from Dir.mode (u32) to Sys_Dir.mode(intptr)

+	# loses the top 4 bytes and ~0 will not match in those circumstances

+	if(dir.qid.qtype == 16rFF && (dir.mode == ~0||big dir.mode == big 16rFFFFFFFF)){

 		dir.mode = d.mode & 8r777;

 		if(d.mode & DLOCK)

 			dir.mode |= DMEXCL;

@@ -1800,8 +1802,9 @@

 	else if(dir.qid.qtype == 16rFF){

 		# nothing to do

 	}

-	else if(dir.mode == ~0)

+	else if(dir.mode == ~0||big dir.mode == big 16rFFFFFFFF){

 		dir.mode = (dir.qid.qtype<<24)|(d.mode & 8r777);

+	}

 	else if(dir.qid.qtype != ((dir.mode>>24) & 16rFF)){

 		d.put();

 		return ferr(f, Eqidmode, file, p1);

--- a/os/port/inferno.c

+++ b/os/port/inferno.c

@@ -385,6 +385,13 @@

 	sd->qid.path = d->qid.path;

 	sd->qid.vers = d->qid.vers;

 	sd->qid.qtype = d->qid.type;

+	/* this is not proper. I should not

+		be checking just for ~0 but also for 16rffffffff

+		while checking for the default value of ~0 */

+	/*if(d->mode == ~0)

+		sd->mode = ~0;

+	else

+		sd->mode = d->mode;*/

 	sd->mode = d->mode;

 	sd->atime = d->atime;

 	sd->mtime = d->mtime;