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auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/14 01:12:43 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, stefanha@redhat.com, vgoyal@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Christophe de Dinechin (dinechin@redhat.com) wrote: > > On 2020-08-27 at 17:36 CEST, Dr. David Alan Gilbert (git) wrote... > > From: "Dr. David Alan Gilbert" > > > > Map xattr names coming from the server, i.e. the host filesystem; > > currently this is only from listxattr. > > > > Signed-off-by: Dr. David Alan Gilbert > > --- > > tools/virtiofsd/passthrough_ll.c | 88 ++++++++++++++++++++++++++++++++ > > 1 file changed, 88 insertions(+) > > > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > > index 9b9c8f3ab1..7cd99186f7 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -2188,6 +2188,42 @@ static int xattr_map_client(const char *client_name, char **out_name) > > abort(); > > } > > > > +/* > > + * For use with listxattr where the server fs gives us a name and we may need > > + * to sanitize this for the client. > > + * Returns a pointer to the result in *out_name > > + * This is always the original string or the current string with some prefix > > + * removed; no reallocation is done. > > + * Returns 0 on success > > + * Can return -ENODATA to indicate the name should be dropped from the list. > > + */ > > +static int xattr_map_server(const char *server_name, const char **out_name) > > > +{ > > + const XattrMapEntry *cur_entry; > > + for (cur_entry = xattr_map_list; ; cur_entry++) { > > + if ((cur_entry->flags & XATTR_MAP_FLAG_SERVER) && > > + (!strncmp(cur_entry->prepend, > > + server_name, > > + strlen(cur_entry->prepend)))) { > > Might be slightly clearer (and possibly faster) as > > strstart(cur_entry->prepend, server_name, &end) I think this is actually, strstart(server_name, cur_entry->prepend, &end) because I think strstart writes the offset into the 1st string into &end expecting the 2nd string to be the thing to test for. Agreed? > > + if (cur_entry->flags & XATTR_MAP_FLAG_END_BAD) { > > + return -ENODATA; > > + } > > + if (cur_entry->flags & XATTR_MAP_FLAG_END_OK) { > > + *out_name = server_name; > > + return 0; > > + } > > + if (cur_entry->flags & XATTR_MAP_FLAG_PREFIX) { > > + /* Remove prefix */ > > + *out_name = server_name + strlen(cur_entry->prepend); > > With the above, that would be > > *out_name = end; OK. > > > + return 0; > > + } > > + } > > + } > > + > > + /* Shouldn't get here - rules should have an END_* */ > > You probably want to point the finger back to parse_xattrmap() in the comment? Done. > > + abort(); > > > +} > > + > > static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, > > size_t size) > > { > > @@ -2342,8 +2378,60 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) > > if (ret == 0) { > > goto out; > > } > > + > > + if (lo->xattrmap) { > > If you put the "XattrMapEntry" pointer in lo, then you would probably test that. Done > > > + /* > > + * Map the names back, some attributes might be dropped, > > + * some shortened, but not increased, so we shouldn't > > + * run out of room. > > + */ > > + size_t out_index, in_index; > > + out_index = 0; > > + in_index = 0; > > + while (in_index < ret) { > > + const char *map_out; > > + char *in_ptr = value + in_index; > > + /* Length of current attribute name */ > > + size_t in_len = strlen(value + in_index) + 1; > > + > > + int mapret = xattr_map_server(in_ptr, &map_out); > > + if (mapret != -ENODATA && mapret != 0) { > > + /* Shouldn't happen */ > > + saverr = -mapret; > > + goto out; > > + } > > + if (mapret == 0) { > > + /* Either unchanged, or truncated */ > > + size_t out_len; > > + if (map_out != in_ptr) { > > + /* +1 copies the NIL */ > > + out_len = strlen(map_out) + 1; > > + } else { > > + /* No change */ > > + out_len = in_len; > > + } > > + /* > > + * Move result along, may still be needed for an unchanged > > + * entry if a previous entry was changed. > > + */ > > + memmove(value + out_index, map_out, out_len); > > + > > + out_index += out_len; > > + } > > + in_index += in_len; > > + } > > + ret = out_index; > > + if (ret == 0) { > > + goto out; > > + } > > + } > > fuse_reply_buf(req, value, ret); > > } else { > > + /* > > + * xattrmap only ever shortens the result, > > + * so we don't need to do anything clever with the > > + * allocation length here. > > + */ > > I don't understand the comment above. We are in the !lo->xattrmap) case, no? No, we're in the else for if (size) { for the case where the caller is trying not to actually get a list of the attributes, but to get a guess of the size of storage needed. Dave > > fuse_reply_xattr(req, ret); > > } > > out_free: > > > -- > Cheers, > Christophe de Dinechin (IRC c3d) -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK