Discover and enumerate EFI block devices

xtldr/CMakeLists.txt

@@ -12,6 +12,7 @@ list(APPEND XTLDR_SOURCE
     ${XTLDR_SOURCE_DIR}/console.c
     ${XTLDR_SOURCE_DIR}/efiutil.c
     ${XTLDR_SOURCE_DIR}/string.c
+    ${XTLDR_SOURCE_DIR}/volume.c
     ${XTLDR_SOURCE_DIR}/xtldr.c)
 
 # Add executable

xtldr/includes/xtbl.h

@@ -13,6 +13,12 @@
 #include <xtklib.h>
 
 
+#define XT_BOOT_DEVICE_UNKNOWN               0x00
+#define XT_BOOT_DEVICE_CDROM                 0x01
+#define XT_BOOT_DEVICE_FLOPPY                0x02
+#define XT_BOOT_DEVICE_HARDDISK              0x03
+#define XT_BOOT_DEVICE_RAMDISK               0x04
+
 /* EFI Image Handle */
 EXTERN EFI_HANDLE EfiImageHandle;
 
@@ -52,6 +58,9 @@ VOID
 BlEfiPrint(IN PUINT16 Format,
            IN ...);
 
+EFI_STATUS
+BlEnumerateEfiBlockDevices();
+
 EFI_STATUS
 BlStartXtLoader(IN EFI_HANDLE ImageHandle,
                 IN PEFI_SYSTEM_TABLE SystemTable);
@@ -61,6 +70,21 @@ BlStringPrint(IN VOID PutChar(IN USHORT Character),
               IN PUINT16 Format,
               IN VA_LIST Arguments);
 
+EFI_STATUS
+BlpDiscoverEfiBlockDevices(PLIST_ENTRY BlockDevices);
+
+PEFI_DEVICE_PATH_PROTOCOL
+BlpDuplicateDevicePath(PEFI_DEVICE_PATH_PROTOCOL DevicePath);
+
+EFI_STATUS
+BlpFindLastEfiBlockDeviceNode(PEFI_DEVICE_PATH_PROTOCOL DevicePath,
+                              PEFI_DEVICE_PATH_PROTOCOL *LastNode);
+
+BOOLEAN
+BlpFindParentEfiBlockDevice(IN PLIST_ENTRY BlockDevices,
+                            IN PEFI_BLOCK_DEVICE_DATA ChildNode,
+                            OUT PEFI_BLOCK_DEVICE_DATA ParentNode);
+
 VOID
 BlpStringFormat(IN VOID PutChar(IN USHORT Character),
                 IN PUINT16 Format,

xtldr/volume.c

@@ -0,0 +1,369 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtldr/volume.c
+ * DESCRIPTION:     XTLDR volume support
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#include <xtbl.h>
+
+
+/* List of available block devices */
+LIST_ENTRY BlBlockDevices;
+
+EFI_STATUS
+BlEnumerateEfiBlockDevices()
+{
+    PEFI_DEVICE_PATH_PROTOCOL LastNode = NULL;
+    PEFI_BLOCK_DEVICE_DATA ParentNode = NULL;
+    PEFI_BLOCK_DEVICE_DATA BlockDeviceData;
+    PEFI_BLOCK_DEVICE BlockDevice;
+    LIST_ENTRY BlockDevices;
+    PLIST_ENTRY ListEntry;
+    EFI_STATUS Status;
+    PEFI_ACPI_HID_DEVICE_PATH AcpiDevice;
+    PEFI_HARDDRIVE_DEVICE_PATH HDPath;
+    PEFI_BLOCK_IO_MEDIA Media;
+    PEFI_GUID PartitionGuid;
+    ULONG DriveNumber, PartitionNumber;
+    USHORT DriveType;
+    ULONG CDCount = 0, FDCount = 0, HDCount = 0, RDCount = 0;
+
+    /* Initialize list entries */
+    RtlInitializeListHead(&BlockDevices);
+    RtlInitializeListHead(&BlBlockDevices);
+
+    /* Discover EFI block devices and store them in linked list */
+    Status = BlpDiscoverEfiBlockDevices(&BlockDevices);
+    if(Status != STATUS_EFI_SUCCESS)
+    {
+        BlDbgPrint(L"ERROR: Failed to discover EFI block devices (status code: %lx)\n", Status);
+        return Status;
+    }
+
+    /* Identify all discovered devices */
+    ListEntry = BlockDevices.Flink;
+    while(ListEntry != &BlockDevices)
+    {
+        /* Take block device from the list */
+        BlockDeviceData = CONTAIN_RECORD(ListEntry, EFI_BLOCK_DEVICE_DATA, ListEntry);
+
+        /* Find last node */
+        Status = BlpFindLastEfiBlockDeviceNode(BlockDeviceData->DevicePath, &LastNode);
+        if(Status != STATUS_EFI_SUCCESS)
+        {
+            BlDbgPrint(L"WARNING: Block device last node not found\n");
+            ListEntry = ListEntry->Flink;
+            continue;
+        }
+
+        /* Set drive type to 'unknown' by default */
+        DriveType = XT_BOOT_DEVICE_UNKNOWN;
+
+        /* Check last node type */
+        if(LastNode->Type == EFI_ACPI_DEVICE_PATH && LastNode->SubType == EFI_ACPI_DP)
+        {
+            /* Check for Floppy EISA identifiers */
+            AcpiDevice = (PEFI_ACPI_HID_DEVICE_PATH)LastNode;
+            if(AcpiDevice->HID == 0x60441D0 || AcpiDevice->HID == 0x70041D0 || AcpiDevice->HID == 0x70141D1)
+            {
+                /* Floppy drive found */
+                Media = BlockDeviceData->BlockIo->Media;
+                DriveType = XT_BOOT_DEVICE_FLOPPY;
+                DriveNumber = FDCount++;
+                PartitionNumber = 0;
+
+                /* Print debug message */
+                BlDbgPrint(L"Found Floppy Disk (DiskNumber: %lu, MediaPresent: %u, RO: %u)\n",
+                           DriveNumber, Media->MediaPresent, Media->ReadOnly);
+            }
+        }
+        else if(LastNode->Type == EFI_MEDIA_DEVICE_PATH)
+        {
+            /* Media device path found */
+            if(LastNode->SubType == EFI_MEDIA_CDROM_DP)
+            {
+                /* Optical drive found */
+                Media = BlockDeviceData->BlockIo->Media;
+                DriveType = XT_BOOT_DEVICE_CDROM;
+                DriveNumber = CDCount++;
+                PartitionNumber = 0;
+
+                /* Print debug message */
+                BlDbgPrint(L"Found CD-ROM drive (DriveNumber: %lu, MediaPresent: %u, RemovableMedia: %u, RO: %u)\n",
+                           DriveNumber, Media->MediaPresent, Media->RemovableMedia, Media->ReadOnly);
+            }
+            else if(LastNode->SubType == EFI_MEDIA_HARDDRIVE_DP)
+            {
+                /* Hard disk partition found */
+                Media = BlockDeviceData->BlockIo->Media;
+                HDPath = (PEFI_HARDDRIVE_DEVICE_PATH)LastNode;
+                DriveType = XT_BOOT_DEVICE_HARDDISK;
+                DriveNumber = (HDPath->PartitionNumber == 1) ? HDCount++ : HDCount - 1;
+                PartitionNumber = HDPath->PartitionNumber;
+                PartitionGuid = (PEFI_GUID)HDPath->Signature;
+
+                /* Print debug message */
+                BlDbgPrint(L"Found Hard Disk partition (DiskNumber: %lu, PartNumber: %u, "
+                           L"MBRType: %u, GUID: {%g}, PartSize: %luB)\n",
+                           DriveNumber, PartitionNumber, HDPath->MBRType,
+                           PartitionGuid, HDPath->PartitionSize * Media->BlockSize);
+            }
+            else if(LastNode->SubType == EFI_MEDIA_RAMDISK_DP)
+            {
+                /* RAM disk found */
+                Media = BlockDeviceData->BlockIo->Media;
+                DriveType = XT_BOOT_DEVICE_RAMDISK;
+                DriveNumber = RDCount++;
+                PartitionNumber = 0;
+
+                /* Print debug message */
+                BlDbgPrint(L"Found RAM Disk (DiskNumber: %lu, MediaPresent: %u)\n",
+                           DriveNumber, Media->MediaPresent);
+            }
+
+            if(!BlpFindParentEfiBlockDevice(&BlockDevices, BlockDeviceData, ParentNode))
+            {
+                BlDbgPrint(L"WARNING: No parent device found, skipping orphaned media device path\n");
+                continue;
+            }
+        }
+
+        /* Make sure the device found has valid type set */
+        if(DriveType != XT_BOOT_DEVICE_UNKNOWN)
+        {
+            /* Allocate memory for block device */
+            Status = BlEfiMemoryAllocatePool(sizeof(EFI_BLOCK_DEVICE), (PVOID *)&BlockDevice);
+            if(Status != STATUS_EFI_SUCCESS)
+            {
+                BlDbgPrint(L"ERROR: Unable to allocate memory pool for block device (status code: %lx)\n", Status);
+                return STATUS_EFI_OUT_OF_RESOURCES;
+            }
+
+            /* Initialize block device */
+            BlockDevice->DevicePath = BlpDuplicateDevicePath(BlockDeviceData->DevicePath);
+            BlockDevice->DriveType = DriveType;
+            BlockDevice->DriveNumber = DriveNumber;
+            BlockDevice->PartitionNumber = PartitionNumber;
+            BlockDevice->PartitionGuid = PartitionGuid;
+
+            /* Add block device to global list */
+            RtlInsertTailList(&BlBlockDevices, &BlockDevice->ListEntry);
+        }
+
+        /* Get next entry from linked list */
+        ListEntry = ListEntry->Flink;
+    }
+
+    /* Return success */
+    return STATUS_EFI_SUCCESS;
+}
+
+EFI_STATUS
+BlpDiscoverEfiBlockDevices(OUT PLIST_ENTRY BlockDevices)
+{
+    EFI_GUID DevicePathGuid = EFI_DEVICE_PATH_PROTOCOL_GUID;
+    EFI_GUID IoGuid = EFI_BLOCK_IO_PROTOCOL_GUID;
+    PEFI_DEVICE_PATH_PROTOCOL DevicePath;
+    PEFI_BLOCK_DEVICE_DATA BlockDevice;
+    UINT_PTR HandlesCount, Index;
+    PEFI_HANDLE Handles = NULL;
+    PEFI_BLOCK_IO_PROTOCOL Io;
+    EFI_STATUS Status;
+
+    /* Locate handles which support the disk I/O interface */
+    Status = EfiSystemTable->BootServices->LocateHandleBuffer(ByProtocol, &IoGuid, NULL, &HandlesCount, &Handles);
+    if(Status != STATUS_EFI_SUCCESS)
+    {
+        /* Failed to locate handles */
+        BlDbgPrint(L"ERROR: Failed to locate block devices handles (status code: %lx)\n", Status);
+        return Status;
+    }
+
+    /* Iterate through all handles */
+    for(Index = 0; Index < HandlesCount; Index++)
+    {
+        /* Print debug message */
+        BlDbgPrint(L"Opening %lu block device from %lu discovered\n", Index + 1, HandlesCount);
+
+        /* Open I/O protocol for given handle */
+        Io = NULL;
+        Status = EfiSystemTable->BootServices->OpenProtocol(Handles[Index], &IoGuid, (PVOID *)&Io, EfiImageHandle,
+                                                            NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
+        if(Status != STATUS_EFI_SUCCESS || Io == NULL)
+        {
+            /* Failed to open I/O protocol, skip it */
+            BlDbgPrint(L"WARNING: Failed to open EFI Block I/O protocol (status code: %lx)\n", Status);
+            continue;
+        }
+
+        /* Check if this is iPXE stub */
+        if(Io->Media && Io->Media->BlockSize == 1 && Io->Media->MediaId == 0x69505845U)
+        {
+            /* Skip stub as it is non-functional */
+            BlDbgPrint(L"WARNING: iPXE stub block I/O protocol");
+            continue;
+        }
+
+        /* Check if DevicePath protocol is supported by this handle */
+        DevicePath = NULL;
+        Status = EfiSystemTable->BootServices->HandleProtocol(Handles[Index], &DevicePathGuid, (PVOID *)&DevicePath);
+        if(Status != STATUS_EFI_SUCCESS || DevicePath == NULL)
+        {
+            /* Device failed to handle DP protocol */
+            BlDbgPrint(L"WARNING: Unable to open DevicePath protocol (status code: %lx)\n", Status);
+            EfiSystemTable->BootServices->CloseProtocol(Handles[Index], &IoGuid, EfiImageHandle, NULL);
+            continue;
+        }
+
+        /* Allocate memory for block device */
+        Status = BlEfiMemoryAllocatePool(sizeof(*BlockDevice), (PVOID *)&BlockDevice);
+        if(Status != STATUS_EFI_SUCCESS)
+        {
+            /* Memory allocation failure */
+            BlDbgPrint(L"ERROR: Unable to allocate memory pool for block device (status code: %lx)\n", Status);
+            EfiSystemTable->BootServices->CloseProtocol(Handles[Index], &DevicePathGuid, EfiImageHandle, NULL);
+            EfiSystemTable->BootServices->CloseProtocol(Handles[Index], &IoGuid, EfiImageHandle, NULL);
+            return Status;
+        }
+
+        /* Store new block device into a linked list */
+        BlockDevice->BlockIo = Io;
+        BlockDevice->DevicePath = DevicePath;
+        RtlInsertTailList(BlockDevices, &BlockDevice->ListEntry);
+    }
+
+    /* Free handles buffer */
+    BlEfiMemoryFreePool(Handles);
+
+    /* Return success */
+    return STATUS_EFI_SUCCESS;
+}
+
+PEFI_DEVICE_PATH_PROTOCOL
+BlpDuplicateDevicePath(IN PEFI_DEVICE_PATH_PROTOCOL DevicePath)
+{
+    PEFI_DEVICE_PATH_PROTOCOL DevicePathNode;
+    PEFI_DEVICE_PATH_PROTOCOL DevicePathClone;
+    EFI_STATUS Status;
+    UINT Length = 0;
+
+    DevicePathNode = DevicePath;
+
+    /* Get the device path length */
+    while(TRUE)
+    {
+        Length += *(PUINT16)DevicePath->Length;
+        if(DevicePathNode->Type == EFI_END_DEVICE_PATH)
+        {
+            break;
+        }
+        DevicePathNode = (PEFI_DEVICE_PATH_PROTOCOL)((PUCHAR)DevicePathNode + *(PUINT16)DevicePath->Length);
+    }
+
+    /* Check length */
+    if(Length == 0)
+    {
+        /* Nothing to duplicate */
+        return NULL;
+    }
+
+    /* Allocate memory for the new device path */
+    Status = BlEfiMemoryAllocatePool(Length, (PVOID *)&DevicePathClone);
+    if(Status != STATUS_EFI_SUCCESS)
+    {
+        /* Failed to allocate memory */
+        BlDbgPrint(L"ERROR: Unable to allocate memory pool for device path duplicate\n");
+        return NULL;
+    }
+
+    /* Copy the device path */
+    RtlCopyMemory(DevicePathClone, DevicePath, Length);
+
+    /* Return the cloned object */
+    return DevicePathClone;
+}
+
+EFI_STATUS
+BlpFindLastEfiBlockDeviceNode(IN PEFI_DEVICE_PATH_PROTOCOL DevicePath,
+                              OUT PEFI_DEVICE_PATH_PROTOCOL *LastNode)
+{
+    PEFI_DEVICE_PATH_PROTOCOL EndNode, NextNode;
+
+    /* Make sure end is not reached yet */
+    if(DevicePath->Type == EFI_END_DEVICE_PATH)
+    {
+        /* End reached, nothing to do */
+        LastNode = NULL;
+        return STATUS_EFI_INVALID_PARAMETER;
+    }
+
+    /* Fast forward to the last node */
+    EndNode = DevicePath;
+    while(EndNode->Type != EFI_END_DEVICE_PATH)
+    {
+        NextNode = EndNode;
+        EndNode = (PEFI_DEVICE_PATH_PROTOCOL)((PUCHAR)EndNode + *(PUSHORT)EndNode->Length);
+    }
+
+    /* Store last node found */
+    *LastNode = NextNode;
+
+    /* Return success */
+    return STATUS_EFI_SUCCESS;
+}
+
+BOOLEAN
+BlpFindParentEfiBlockDevice(IN PLIST_ENTRY BlockDevices,
+                            IN PEFI_BLOCK_DEVICE_DATA ChildNode,
+                            OUT PEFI_BLOCK_DEVICE_DATA ParentNode)
+{
+    PEFI_DEVICE_PATH_PROTOCOL ChildDevicePath, ParentDevicePath;
+    PEFI_BLOCK_DEVICE_DATA BlockDeviceData;
+    UINT ChildLength, ParentLength;
+    PLIST_ENTRY ListEntry;
+
+    ListEntry = BlockDevices->Flink;
+    while(ListEntry != BlockDevices)
+    {
+        /* Take block device from the list */
+        BlockDeviceData = CONTAIN_RECORD(ListEntry, EFI_BLOCK_DEVICE_DATA, ListEntry);
+
+        ChildDevicePath = ChildNode->DevicePath;
+        ParentDevicePath = BlockDeviceData->DevicePath;
+
+        /* Iterate nodes */
+        while(TRUE)
+        {
+            /* Check if the parent device is a match */
+            if(ParentDevicePath->Type == EFI_END_DEVICE_PATH)
+            {
+                /* Parent device is a match */
+                ParentNode = BlockDeviceData;
+                return TRUE;
+            }
+
+            /* Get child and parent node lengths */
+            ChildLength = *(PUINT16)ChildDevicePath->Length;
+            ParentLength = *(PUINT16)ParentDevicePath->Length;
+
+            /* Check if lengths match */
+            if(ChildLength != ParentLength)
+            {
+                /* Lengths do not match, this is not a valid parent */
+                break;
+            }
+
+            /* Move to the next child and parent nodes */
+            ChildDevicePath = (PEFI_DEVICE_PATH_PROTOCOL)((PUCHAR)ChildDevicePath + ChildLength);
+            ParentDevicePath = (PEFI_DEVICE_PATH_PROTOCOL)((PUCHAR)ParentDevicePath + ParentLength);
+        }
+
+        /* Get next entry from linked list */
+        ListEntry = ListEntry->Flink;
+    }
+
+    /* Apparently not found a parent node */
+    return FALSE;
+}

xtldr/xtldr.c

@@ -60,6 +60,9 @@ BlStartXtLoader(IN EFI_HANDLE ImageHandle,
         BlDbgPrint(L"WARNING: Failed to disable watchdog timer\n");
     }
 
+    /* Discover and enumerate EFI block devices */
+    BlEnumerateEfiBlockDevices();
+
     /* Infinite bootloader loop */
     for(;;);