Messages in this thread | | | From | Andreas Gruenbacher <> | Subject | Re: Generic infrastructure for acls | Date | Sat, 2 Sep 2006 00:32:02 +0200 |
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On Friday, 01 September 2006 23:44, Andrew Morton wrote: > On Sat, 02 Sep 2006 00:14:22 +0200 > > Andreas Gruenbacher <agruen@suse.de> wrote: > > +generic_acl_list(struct inode *inode, struct generic_acl_operations > > *ops, + int type, char *list, size_t list_size) > > +{ > > + struct posix_acl *acl; > > + const char *name; > > + size_t size; > > + > > + acl = ops->getacl(inode, type); > > + if (!acl) > > + return 0; > > + posix_acl_release(acl); > > + > > + switch(type) { > > + case ACL_TYPE_ACCESS: > > + name = POSIX_ACL_XATTR_ACCESS; > > + break; > > + > > + case ACL_TYPE_DEFAULT: > > + name = POSIX_ACL_XATTR_DEFAULT; > > + break; > > + > > + default: > > + return 0; > > + } > > + size = strlen(name) + 1; > > + if (list && size <= list_size) > > + memcpy(list, name, size); > > + return size; > > +} > > That's a clumsy-looking interface.
We could get rid of the switch by passing in the type and the name, but otherwise that's pretty exactly what's needed, no matter if done in a fs-dependent or independent way.
> How is the caller to know that *list got filled in? By checking the generic_acl_list() return value against `list_size'?
The return value determines how many bytes have been used or would be needed in the buffer -- generic_listxattr() in fs/xattr.c has this code:
> for_each_xattr_handler(handlers, handler) { > size = handler->list(inode, buf, buffer_size, NULL, 0); > if (size > buffer_size) > return -ERANGE; > buf += size; > buffer_size -= size; > }
Andreas
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