On Sat, Mar 19, 2022 at 10:11:41AM +0100, Heinrich Schuchardt wrote: > efi_dp_find_obj() should not return any handle with a partially matching > device path
If so, please describe so explicitly in the function's description. See below. > but the handle with the maximum matching device path. > > Signed-off-by: Heinrich Schuchardt <[email protected]> > --- > v2: > new patch > --- > include/efi_loader.h | 4 +- > lib/efi_loader/efi_device_path.c | 110 +++++++++++++++++-------------- > 2 files changed, 63 insertions(+), 51 deletions(-) > > diff --git a/include/efi_loader.h b/include/efi_loader.h > index 1ffcdfc485..6271d40125 100644 > --- a/include/efi_loader.h > +++ b/include/efi_loader.h > @@ -730,8 +730,8 @@ struct efi_device_path *efi_dp_shorten(struct > efi_device_path *dp); > struct efi_device_path *efi_dp_next(const struct efi_device_path *dp); > int efi_dp_match(const struct efi_device_path *a, > const struct efi_device_path *b); > -struct efi_object *efi_dp_find_obj(struct efi_device_path *dp, > - struct efi_device_path **rem); > +efi_handle_t efi_dp_find_obj(struct efi_device_path *dp, > + struct efi_device_path **rem); > /* get size of the first device path instance excluding end node */ > efi_uintn_t efi_dp_instance_size(const struct efi_device_path *dp); > /* size of multi-instance device path excluding end node */ > diff --git a/lib/efi_loader/efi_device_path.c > b/lib/efi_loader/efi_device_path.c > index ddd5f132ec..aeb5264820 100644 > --- a/lib/efi_loader/efi_device_path.c > +++ b/lib/efi_loader/efi_device_path.c > @@ -159,69 +159,81 @@ struct efi_device_path *efi_dp_shorten(struct > efi_device_path *dp) > return dp; > } > > -static struct efi_object *find_obj(struct efi_device_path *dp, bool > short_path, > - struct efi_device_path **rem) > +/** > + * find_handle() - find handle by device path > + * > + * If @rem is provided, the handle with the longest partial match is > returned. > + * > + * @dp: device path to search > + * @short_path: use short form device path for matching > + * @rem: pointer to receive remaining device path > + * Return: matching handle > + */ > +static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path, > + struct efi_device_path **rem) > { > - struct efi_object *efiobj; > - efi_uintn_t dp_size = efi_dp_instance_size(dp); > + efi_handle_t handle, best_handle = NULL; > + efi_uintn_t len, best_len = 0; > + > + len = efi_dp_instance_size(dp); > > - list_for_each_entry(efiobj, &efi_obj_list, link) { > + list_for_each_entry(handle, &efi_obj_list, link) { > struct efi_handler *handler; > - struct efi_device_path *obj_dp; > + struct efi_device_path *dp_current; > + efi_uintn_t len_current; > efi_status_t ret; > > - ret = efi_search_protocol(efiobj, > - &efi_guid_device_path, &handler); > + ret = efi_search_protocol(handle, &efi_guid_device_path, > + &handler); > if (ret != EFI_SUCCESS) > continue; > - obj_dp = handler->protocol_interface; > - > - do { > - if (efi_dp_match(dp, obj_dp) == 0) { > - if (rem) { > - /* > - * Allow partial matches, but inform > - * the caller. > - */ > - *rem = ((void *)dp) + > - efi_dp_instance_size(obj_dp); > - return efiobj; > - } else { > - /* Only return on exact matches */ > - if (efi_dp_instance_size(obj_dp) == > - dp_size) > - return efiobj; > - } > - } > - > - obj_dp = efi_dp_shorten(efi_dp_next(obj_dp)); > - } while (short_path && obj_dp); > + dp_current = handler->protocol_interface; > + if (short_path) { > + dp_current = efi_dp_shorten(dp_current); > + if (!dp_current) > + continue; > + } > + len_current = efi_dp_instance_size(dp_current); > + if (rem) { > + if (len_current < len) > + continue; > + } else { > + if (len_current != len) > + continue; > + } > + if (memcmp(dp_current, dp, len)) > + continue; > + if (!rem) > + return handle; > + if (len_current > best_len) { > + best_len = len_current; > + best_handle = handle; > + *rem = (void*)((u8 *)dp + len_current); > + } > } > - > - return NULL; > + return best_handle; > } > > -/* > - * Find an efiobj from device-path, if 'rem' is not NULL, returns the > - * remaining part of the device path after the matched object. > +/** > + * efi_dp_find_obj() - find handle by device path > + * > + * If @rem is provided, the handle with the longest partial match is > returned. What if @rem == NULL. > + * > + * @dp: device path to search > + * @rem: pointer to receive remaining device path > + * Return: matching handle > */ > -struct efi_object *efi_dp_find_obj(struct efi_device_path *dp, > - struct efi_device_path **rem) > +efi_handle_t efi_dp_find_obj(struct efi_device_path *dp, > + struct efi_device_path **rem) The return type was also changed. Why not change the function name to, say, efi_dp_find_handle() "object" is an internal representation. -Takahiro Akashi > { > - struct efi_object *efiobj; > - > - /* Search for an exact match first */ > - efiobj = find_obj(dp, false, NULL); > - > - /* Then for a fuzzy match */ > - if (!efiobj) > - efiobj = find_obj(dp, false, rem); > + efi_handle_t handle; > > - /* And now for a fuzzy short match */ > - if (!efiobj) > - efiobj = find_obj(dp, true, rem); > + handle = find_handle(dp, false, rem); > + if (!handle) > + /* Match short form device path */ > + handle = find_handle(dp, true, rem); > > - return efiobj; > + return handle; > } > > /* > -- > 2.34.1 >
