extattr_get_file(2): clarify RETURN VALUES

While some of the syscalls' behavior were documented and implied in the
RETURN VALUES section by earlier, e.g., the DESCRIPTION sections, as having
behavior of the other calls (`*_fd` vs `*_file` vs `*_link`), there was a lot
of implied return value behavior in the section prior to this change.

Explicitly document the syscall behavior per the current implementation in
sys/kern/vfs_extattr.c so others can better develop based on its explicit
documented behavior instead of having to digest the context of the manpage to
understand the appropriate behavior.

MFC after:	1 week
MFC with:	r368431, r368433, r368434
Sponsored by:	DellEMC Isilon
This commit is contained in:
Enji Cooper 2020-12-08 04:16:05 +00:00
parent f705523939
commit cf681016d4

View File

@ -169,21 +169,32 @@ For more information on named extended attributes, please see
.Xr extattr 9 .
.Sh RETURN VALUES
If successful, the
.Fn extattr_get_fd ,
.Fn extattr_get_file ,
.Fn extattr_get_link ,
.Fn extattr_list_fd ,
.Fn extattr_list_file ,
.Fn extattr_list_link ,
.Fn extattr_set_fd ,
.Fn extattr_set_file ,
and
.Fn extattr_list_file
.Fn extattr_set_link
calls return the number of bytes
that were read or written from the
.Fa data ,
respectively, or if
respectively.
If
.Fa data
was
.Dv NULL ,
then
.Fn extattr_get_file
.Fn extattr_get_fd ,
.Fn extattr_get_file ,
.Fn extattr_get_link ,
.Fn extattr_list_fd ,
.Fn extattr_list_file ,
and
.Fn extattr_list_file
.Fn extattr_list_link
return the number of bytes available to read.
If any of the calls are unsuccessful, the value \-1 is returned
and the global variable