Hi,
here is another POSIX compatibility change I found while running
NetBSD system call tests:
The incompatibilities can be reproduced with the followding comands:
`mv / foo`
mv: rename / to foo: Is a directory
`man 2 rename` mentions EISDIR:
[EISDIR] to is a directory, but from is not a directory.
Which is mentioned similarly in POSIX. But it doesn't fit the current case.
`mkdir /`
mkdir: /: Is a directory
EISDIR is not mentioned in `man 2 mkdir`. Also not mentioned in POSIX.
I believe EBUSY would be good here.
`rmdir /`
rmdir: /: Is a directory
EISDIR is not mentioned in `man 2 rmdir`. Also not mentioned in POSIX.
unlink("/");
printf("%d\n", errno);
21 // EISDIR
Also neither mentioned in man nor POSIX.
Here is some POSIX references:
https://pubs.opengroup.org/onlinepubs/9699919799/
unlink (2):
[EBUSY]
The file named by the path argument cannot be unlinked because it is
being used by the system or another process and the implementation
considers this an error.
rename (2):
[EBUSY]
The directory named by old or new is currently in use by the system or
another process, and the implementation considers this an error.
rmdir (2):
[EBUSY]
The directory to be removed is currently in use by the system or
some process and the implementation considers this to be an error.
mkdir (2):
[EEXIST]
The named file exists.
Attached is a patch that will make mkdir return EEXIST, EBUSY for others.
I believe this corer case is quite essential as it is in namei because of
this (and because NetBSD and FreeBSD differ a lot in the vfs area) I hope
for some comments on this.
The patched code hasn't changed a lot since 44BSD. duh POSIX.
There already were discussions on EISDIR in the past: (from unlink POSIX)
> The standard developers reviewed TR 24715-2006 and noted that LSB-conforming
> implementations may return [EISDIR] instead of [EPERM] when unlinking a
> directory. A change to permit this behavior by changing the requirement for
> [EPERM] to [EPERM] or [EISDIR] was considered, but decided against since it
> would break existing strictly conforming and conforming applications.
> Applications written for portability to both POSIX.1-2017 and the LSB should
> be prepared to handle either error code.
duh.
thanks,
mbuhl
Index: sys/kern/vfs_lookup.c
===================================================================
RCS file: /cvs/src/sys/kern/vfs_lookup.c,v
retrieving revision 1.80
diff -u -p -r1.80 vfs_lookup.c
--- sys/kern/vfs_lookup.c 18 Jul 2019 18:06:17 -0000 1.80
+++ sys/kern/vfs_lookup.c 22 Jul 2019 16:10:14 -0000
@@ -440,7 +440,10 @@ vfs_lookup(struct nameidata *ndp)
*/
if (cnp->cn_nameptr[0] == '\0') {
if (ndp->ni_dvp == NULL && wantparent) {
- error = EISDIR;
+ if (cnp->cn_nameiop == CREATE)
+ error = EEXIST;
+ else
+ error = EBUSY;
goto bad;
}
ndp->ni_vp = dp;
Index: lib/libc/sys/rename.2
===================================================================
RCS file: /cvs/src/lib/libc/sys/rename.2,v
retrieving revision 1.22
diff -u -p -r1.22 rename.2
--- lib/libc/sys/rename.2 10 Sep 2015 17:55:21 -0000 1.22
+++ lib/libc/sys/rename.2 22 Jul 2019 16:45:16 -0000
@@ -123,6 +123,12 @@ characters, or an entire pathname (inclu
exceeded
.Dv PATH_MAX
bytes.
+.It Bq Er EBUSY
+The directory containing
+.Fa from
+or
+.Fa to
+is currently in use by the system.
.It Bq Er ENOENT
A component of the
.Fa from
