Up until now we've displayed our forms in the same app that populated it to the HII Database. But this is not a standard approach. Usually UEFI drivers populate HII Forms and another application loads them. As we are going to create more complicated forms that would have actual non-volatile settings, it is time to separate these two functionalities. For this we need to: - convert our HII Form UEFI application to the UEFI driver form - create an application that would be able to load populated HII Forms from the HII database # `DisplayHIIByGuid` Let's start with the second task. Create `DisplayHIIByGuid` UEFI Shell application. `UefiLessonsPkg/DisplayHIIByGuid/DisplayHIIByGuid.inf` ``` [Defines] INF_VERSION = 1.25 BASE_NAME = DisplayHIIByGuid FILE_GUID = 1597e1d0-7f62-4631-a166-703f03bd7223 MODULE_TYPE = UEFI_APPLICATION VERSION_STRING = 1.0 ENTRY_POINT = ShellCEntryLib [Sources] DisplayHIIByGuid.c [Packages] MdePkg/MdePkg.dec [LibraryClasses] UefiApplicationEntryPoint UefiLib ShellCEntryLib ``` `UefiLessonsPkg/DisplayHIIByGuid/DisplayHIIByGuid.c` ``` #include #include INTN EFIAPI ShellAppMain ( IN UINTN Argc, IN CHAR16 **Argv ) { return EFI_SUCCESS; } ``` Add new app to the `UefiLessonsPkg/UefiLessonsPkg.dsc` ``` [Components] ... UefiLessonsPkg/DisplayHIIByGuid/DisplayHIIByGuid.inf ``` Our application would take HII Package List GUID from the command argument and display HII Forms from that package. First we need to parse argument string to GUID value. For this task we can utilize `StrToGuid` function from the https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Library/BaseLib.h ``` /** Convert a Null-terminated Unicode GUID string to a value of type EFI_GUID. ... If String is not aligned in a 16-bit boundary, then ASSERT(). @param String Pointer to a Null-terminated Unicode string. @param Guid Pointer to the converted GUID. @retval RETURN_SUCCESS Guid is translated from String. @retval RETURN_INVALID_PARAMETER If String is NULL. If Data is NULL. @retval RETURN_UNSUPPORTED If String is not as the above format. **/ RETURN_STATUS EFIAPI StrToGuid ( IN CONST CHAR16 *String, OUT GUID *Guid ); ``` Use it like this: ``` if (Argc != 2) { Print(L"Usage:\n"); Print(L" DisplayHIIByGuid \n"); return EFI_INVALID_PARAMETER; } EFI_GUID PackageListGuid; EFI_STATUS Status = StrToGuid(Argv[1], &PackageListGuid); if (Status != RETURN_SUCCESS) { Print(L"Error! Can't convert argument to GUID\n"); return EFI_INVALID_PARAMETER; } ``` Now when we have Package List GUID we can get HII Handles for this GUID with the help of the `HiiGetHiiHandles` function https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Include/Library/HiiLib.h https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/UefiHiiLib/HiiLib.c ``` /** Retrieves the array of all the HII Handles or the HII handles of a specific package list GUID in the HII Database. This array is terminated with a NULL HII Handle. This function allocates the returned array using AllocatePool(). The caller is responsible for freeing the array with FreePool(). @param[in] PackageListGuid An optional parameter that is used to request HII Handles associated with a specific Package List GUID. If this parameter is NULL, then all the HII Handles in the HII Database are returned. If this parameter is not NULL, then zero or more HII Handles associated with PackageListGuid are returned. @retval NULL No HII handles were found in the HII database @retval NULL The array of HII Handles could not be retrieved @retval Other A pointer to the NULL terminated array of HII Handles **/ EFI_HII_HANDLE * EFIAPI HiiGetHiiHandles ( IN CONST EFI_GUID *PackageListGuid OPTIONAL ) ; ``` In our code we can use it as simple as: ``` EFI_HII_HANDLE* HiiHandles = HiiGetHiiHandles(&PackageListGuid); ... FreePool(HiiHandles); ``` Don't forget to include `#include ` to our `*.c` file and add this library to our `*.inf` file: ``` [Packages] ... MdeModulePkg/MdeModulePkg.dec [LibraryClasses] ... HiiLib ``` Now we have a pointer to the HII Handle array associated with our GUID. But before we call `SendForm` we need to calculate how many element this array has. For this copy `HiiHandles` data and loop over its elements until encounter NULL: ``` EFI_HII_HANDLE* HiiHandle = HiiHandles; UINTN HandleCount=0; while (*HiiHandle != NULL) { HiiHandle++; HandleCount++; } ``` Now we have everything we need. It is time to call `SendForm` function from the `EFI_FORM_BROWSER2_PROTOCOL`. Add this include to our `*.c` file `#include ` and this code to our `*.inf` file: ``` [Protocols] gEfiFormBrowser2ProtocolGuid ``` Actual code to call the protocol: ``` EFI_FORM_BROWSER2_PROTOCOL* FormBrowser2; Status = gBS->LocateProtocol(&gEfiFormBrowser2ProtocolGuid, NULL, (VOID**)&FormBrowser2); if (EFI_ERROR(Status)) { Print(L"Error! Can't locate gEfiFormBrowser2Protocol\n"); FreePool(HiiHandles); return Status; } Status = FormBrowser2->SendForm ( FormBrowser2, HiiHandles, HandleCount, NULL, 0, NULL, NULL ); if (EFI_ERROR(Status)) { Print(L"Error! SendForm returned %r\n", Status); } ``` Compile our application and copy it to the shared disk folder. Earlier we've created `ShowHII` program that shows all the package lists from HII database: ``` FS0:\> ShowHII.efi PackageList[0]: GUID=A487A478-51EF-48AA-8794-7BEE2A0562F1; size=0x1ADC Package[0]: type=STRINGS; size=0x1AC4 Package[1]: type=END; size=0x4 PackageList[1]: GUID=19618BCE-55AE-09C6-37E9-4CE04084C7A1; size=0x21E4 Package[0]: type=STRINGS; size=0x21CC Package[1]: type=END; size=0x4 PackageList[2]: GUID=2F30DA26-F51B-4B6F-85C4-31873C281BCA; size=0xA93 Package[0]: type=STRINGS; size=0xA7B Package[1]: type=END; size=0x4 PackageList[3]: GUID=F74D20EE-37E7-48FC-97F7-9B1047749C69; size=0x2EE9 Package[0]: type=IMAGES; size=0x2ED1 Package[1]: type=END; size=0x4 PackageList[4]: GUID=EBF8ED7C-0DD1-4787-84F1-F48D537DCACF; size=0x46C Package[0]: type=FORMS; size=0x82 Package[1]: type=FORMS; size=0x82 Package[2]: type=STRINGS; size=0x199 Package[3]: type=STRINGS; size=0x19B Package[4]: type=DEVICE_PATH; size=0x1C Package[5]: type=END; size=0x4 PackageList[5]: GUID=FE561596-E6BF-41A6-8376-C72B719874D0; size=0x93F Package[0]: type=FORMS; size=0xF5 Package[1]: type=STRINGS; size=0x40A Package[2]: type=STRINGS; size=0x40C Package[3]: type=DEVICE_PATH; size=0x1C Package[4]: type=END; size=0x4 PackageList[6]: GUID=2A46715F-3581-4A55-8E73-2B769AAA30C5; size=0x6B0 Package[0]: type=FORMS; size=0x143 Package[1]: type=STRINGS; size=0x539 Package[2]: type=DEVICE_PATH; size=0x1C Package[3]: type=END; size=0x4 PackageList[7]: GUID=99FDC8FD-849B-4EBA-AD13-FB9699C90A4D; size=0x6FE Package[0]: type=STRINGS; size=0x340 Package[1]: type=STRINGS; size=0x3A6 Package[2]: type=END; size=0x4 PackageList[8]: GUID=E38C1029-E38F-45B9-8F0D-E2E60BC9B262; size=0x15DA Package[0]: type=STRINGS; size=0xA88 Package[1]: type=STRINGS; size=0xB3A Package[2]: type=END; size=0x4 PackageList[9]: GUID=D9DCC5DF-4007-435E-9098-8970935504B2; size=0x855 Package[0]: type=FORMS; size=0x1F6 Package[1]: type=STRINGS; size=0x62B Package[2]: type=DEVICE_PATH; size=0x1C Package[3]: type=END; size=0x4 PackageList[10]: GUID=F5F219D3-7006-4648-AC8D-D61DFB7BC6AD; size=0x14EC Package[0]: type=SIMPLE_FONTS; size=0x14D4 Package[1]: type=END; size=0x4 PackageList[11]: GUID=4B47D616-A8D6-4552-9D44-CCAD2E0F4CF9; size=0x6AC8 Package[0]: type=FORMS; size=0x1030 Package[1]: type=STRINGS; size=0x3C99 Package[2]: type=STRINGS; size=0x1DCB Package[3]: type=DEVICE_PATH; size=0x1C Package[4]: type=END; size=0x4 PackageList[12]: GUID=F95A7CCC-4C55-4426-A7B4-DC8961950BAE; size=0x13909 Package[0]: type=STRINGS; size=0x138F1 Package[1]: type=END; size=0x4 PackageList[13]: GUID=DEC5DAA4-6781-4820-9C63-A7B0E4F1DB31; size=0x8677 Package[0]: type=STRINGS; size=0x865F Package[1]: type=END; size=0x4 PackageList[14]: GUID=4344558D-4EF9-4725-B1E4-3376E8D6974F; size=0x83BD Package[0]: type=STRINGS; size=0x83A5 Package[1]: type=END; size=0x4 PackageList[15]: GUID=0AF0B742-63EC-45BD-8DB6-71AD7F2FE8E8; size=0xCB04 Package[0]: type=STRINGS; size=0xCAEC Package[1]: type=END; size=0x4 PackageList[16]: GUID=25F200AA-D3CB-470A-BF51-E7D162D22E6F; size=0x1D3D7 Package[0]: type=STRINGS; size=0x1D3BF Package[1]: type=END; size=0x4 PackageList[17]: GUID=5F5F605D-1583-4A2D-A6B2-EB12DAB4A2B6; size=0x3048 Package[0]: type=STRINGS; size=0x3030 Package[1]: type=END; size=0x4 PackageList[18]: GUID=F3D301BB-F4A5-45A8-B0B7-FA999C6237AE; size=0x26B5 Package[0]: type=STRINGS; size=0x269D Package[1]: type=END; size=0x4 PackageList[19]: GUID=7C04A583-9E3E-4F1C-AD65-E05268D0B4D1; size=0x5CB Package[0]: type=STRINGS; size=0x5B3 Package[1]: type=END; size=0x4 ``` Now we can use our newly created `DisplayHIIByGuid` application to show forms from the HII Database. Try to execute the following commands: ``` FS0:\> DisplayHIIByGuid.efi EBF8ED7C-0DD1-4787-84F1-F48D537DCACF FS0:\> DisplayHIIByGuid.efi FE561596-E6BF-41A6-8376-C72B719874D0 FS0:\> DisplayHIIByGuid.efi 2A46715F-3581-4A55-8E73-2B769AAA30C5 FS0:\> DisplayHIIByGuid.efi D9DCC5DF-4007-435E-9098-8970935504B2 FS0:\> DisplayHIIByGuid.efi 4B47D616-A8D6-4552-9D44-CCAD2E0F4CF9 ``` These GUIDs corresponds to: - `EBF8ED7C-0DD1-4787-84F1-F48D537DCACF` https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Universal/DriverHealthManagerDxe/DriverHealthManagerDxe.inf - `FE561596-E6BF-41A6-8376-C72B719874D0` `EFI_FILE_EXPLORE_FORMSET_GUID` https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/FileExplorerLib/FormGuid.h - `2A46715F-3581-4A55-8E73-2B769AAA30C5` `RAM_DISK_FORM_SET_GUID` `gRamDiskFormSetGuid` https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Include/Guid/RamDiskHii.h https://github.com/tianocore/edk2/blob/master/MdeModulePkg/MdeModulePkg.dec - `D9DCC5DF-4007-435E-9098-8970935504B2` https://github.com/tianocore/edk2/blob/master/OvmfPkg/PlatformDxe/Platform.inf - `4B47D616-A8D6-4552-9D44-CCAD2E0F4CF9` `gIScsiConfigGuid` `ISCSI_CONFIG_GUID` https://github.com/tianocore/edk2/blob/master/NetworkPkg/Include/Guid/IScsiConfigHii.h https://github.com/tianocore/edk2/blob/master/NetworkPkg/NetworkPkg.dec For example we can get this output on the command `DisplayHIIByGuid.efi D9DCC5DF-4007-435E-9098-8970935504B2`: ![OVMF_Settings_Form.png](OVMF_Settings_Form.png?raw=true "OVMF Settings Form") # Formset `classguid` If you've tried `DisplayHIIByGuid.efi` on all of the package lists with forms, you could notice that one GUID doesn't work: ``` FS0:\> DisplayHIIByGuid.efi FE561596-E6BF-41A6-8376-C72B719874D0 Error! SendForm returned Not found ``` Once again this is the GUID: - `FE561596-E6BF-41A6-8376-C72B719874D0` `EFI_FILE_EXPLORE_FORMSET_GUID` https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/FileExplorerLib/FormGuid.h Let's look again at the `EFI_FORM_BROWSER2_PROTOCOL.SendForm()` description: ``` EFI_FORM_BROWSER2_PROTOCOL.SendForm() Summary: Initialize the browser to display the specified configuration forms. Prototype: typedef EFI_STATUS (EFIAPI *EFI_SEND_FORM2) ( IN CONST EFI_FORM_BROWSER2_PROTOCOL *This, IN EFI_HII_HANDLE *Handles, IN UINTN HandleCount, IN CONST EFI_GUID *FormsetGuid, OPTIONAL IN EFI_FORM_ID FormId, OPTIONAL IN CONST EFI_SCREEN_DESCRIPTOR *ScreenDimensions, OPTIONAL OUT EFI_BROWSER_ACTION_REQUEST *ActionRequest OPTIONAL ); Parameters: This A pointer to the EFI_FORM_BROWSER2_PROTOCOL instance. Handles A pointer to an array of HII handles to display. HandleCount The number of handles in the array specified by Handle. FormsetGuid This field points to the EFI_GUID which must match the Guid field or one of the elements of the ClassId field in the EFI_IFR_FORM_SET op-code. If FormsetGuid is NULL, then this function will display the form set class EFI_HII_PLATFORM_SETUP_FORMSET_GUID. FormId This field specifies the identifier of the form within the form set to render as the first displayable page. If this field has a value of 0x0000, then the Forms Browser will render the first enabled form in the form set. ScreenDimensions Points to recommended form dimensions, including any non-content area, in characters. ActionRequested Points to the action recommended by the form. Description: This function is the primary interface to the Forms Browser. The Forms Browser displays the forms specified by FormsetGuid and FormId from all of HII handles specified by Handles. If more than one form can be displayed, the Forms Browser will provide some means for the user to navigate between the forms in addition to that provided by cross-references in the forms themselves. ``` Up until now we've used `FormsetGuid = NULL` in all of the function calls. Which according to the descriptio means that `EFI_HII_PLATFORM_SETUP_FORMSET_GUID` is used. Also earlier we've investigated that if don't explicitly declare `classguid` for our formset, IFR will still has default value which is equal to the same `EFI_HII_PLATFORM_SETUP_FORMSET_GUID`. This is the reason why all of our `SendForm` calls have worked up until now. But if you look at the VFR code of the form from the problematic package list (https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/FileExplorerLib/FileExplorerVfr.vfr) you would see that this form uses different `classguid`: ``` formset guid = EFI_FILE_EXPLORE_FORMSET_GUID, title = STRING_TOKEN(STR_FILE_EXPLORER_TITLE), help = STRING_TOKEN(STR_NULL_STRING), classguid = EFI_FILE_EXPLORE_FORMSET_GUID, ``` In fact it is the same GUID that package list has. To correctly display formsets with `classguid` different from the default value (`EFI_HII_PLATFORM_SETUP_FORMSET_GUID`) we need to add a possibility to get this GUID from user. First we need to modify program description a little bit: ``` - if (Argc != 2) { + if ((Argc < 2) || (Argc > 3)) { Print(L"Usage:\n"); - Print(L" DisplayHIIByGuid \n"); + Print(L" DisplayHIIByGuid []\n"); return EFI_INVALID_PARAMETER; } ``` Then add new argument handling: ``` EFI_GUID FormsetClassGuid = EFI_HII_PLATFORM_SETUP_FORMSET_GUID; if (Argc == 3) { Status = StrToGuid(Argv[2], &FormsetClassGuid); if (Status != RETURN_SUCCESS) { Print(L"Error! Can't convert argument to GUID\n"); return EFI_INVALID_PARAMETER; } } ``` And finally `FormsetClassGuid` in our `SendForm` call: ``` Status = FormBrowser2->SendForm ( FormBrowser2, HiiHandles, HandleCount, - NULL, + &FormsetClassGuid, 0, NULL, NULL ); ``` Now you can verify that with a: ``` FS0:\> DisplayHIIByGuid.efi FE561596-E6BF-41A6-8376-C72B719874D0 FE561596-E6BF-41A6-8376-C72B719874D0 ``` We can correctly display the File Explorer form: ![FileExplorer](FileExplorer.png?raw=true "FileExplorer") # `HIIStaticFormDriver` Now let's create `HIIStaticFormDriver` UEFI driver that would be a copy of a `HIIStaticForm` UEFI application that we've created earlier, except that it would be a driver: ``` $ ./createNewDriver.sh HIIStaticFormDriver $ cp UefiLessonsPkg/HIIStaticForm/Form.vfr UefiLessonsPkg/HIIStaticFormDriver/ $ cp UefiLessonsPkg/HIIStaticForm/Strings.uni UefiLessonsPkg/HIIStaticFormDriver/ ``` Here is full code for the `HIIStaticFormDriver` `*.c` and `*.inf` files. You can compare it with a `HIIStaticForm` application code. `UefiLessonsPkg/HIIStaticFormDriver/HIIStaticFormDriver.inf`: ``` [Defines] INF_VERSION = 1.25 BASE_NAME = HIIStaticFormDriver FILE_GUID = 22514099-ad3b-45ec-b14b-112eb6446db2 MODULE_TYPE = UEFI_DRIVER VERSION_STRING = 1.0 ENTRY_POINT = HIIStaticFormDriverEntryPoint UNLOAD_IMAGE = HIIStaticFormDriverUnload [Sources] HIIStaticFormDriver.c Strings.uni Form.vfr [Packages] MdePkg/MdePkg.dec MdeModulePkg/MdeModulePkg.dec [LibraryClasses] UefiDriverEntryPoint UefiLib HiiLib ``` `UefiLessonsPkg/HIIStaticFormDriver/HIIStaticFormDriver.c`: ``` #include #include #include extern UINT8 FormBin[]; EFI_HII_HANDLE Handle; EFI_STATUS EFIAPI HIIStaticFormDriverUnload ( EFI_HANDLE ImageHandle ) { if (Handle != NULL) HiiRemovePackages(Handle); return EFI_SUCCESS; } EFI_STATUS EFIAPI HIIStaticFormDriverEntryPoint ( IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable ) { Handle = HiiAddPackages( &gEfiCallerIdGuid, NULL, HIIStaticFormDriverStrings, FormBin, NULL ); if (Handle == NULL) return EFI_OUT_OF_RESOURCES; return EFI_SUCCESS; } ``` Build `HIIStaticFormDriver`, run UEFI shell and load it: ``` FS0:\> load HIIStaticFormDriver.efi Image 'FS0:\HIIStaticFormDriver.efi' loaded at 688A000 - Success ``` You can see that our driver have populated new data to the HII Database: ``` FS0:\> ShowHII.efi ... PackageList[20]: GUID=22514099-AD3B-45EC-B14B-112EB6446DB2; size=0x28B Package[0]: type=FORMS; size=0x98 Package[1]: type=STRINGS; size=0x1DB Package[2]: type=END; size=0x4 ``` And with a help of our `DisplayHIIByGuid.efi` application you can see the populated HII data: ``` FS0:\> DisplayHIIByGuid.efi 22514099-AD3B-45EC-B14B-112EB6446DB2 ``` ![HII_static_form](HII_static_form.png?raw=true "HII Static Form")