EDK2写UEFI代码，使用UnicodeSPrint 函数拼接字符串pci bus dev fun >> txt并用ShellProtocol->Execute函数执行

以下是示例代码：

#include <Uefi.h>
#include <Library/UefiLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/Shell.h>
#include <Library/BaseLib.h>
#include <Library/PrintLib.h>

EFI_STATUS
EFIAPI
UefiMain(
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS Status;
  EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL* PciRootBridgeIo;
  UINTN Segment, Bus, Device, Function;

  // Retrieve the PCI Root Bridge IO Protocol
  Status = gBS->LocateProtocol(&gEfiPciRootBridgeIoProtocolGuid, NULL, (VOID**)&PciRootBridgeIo);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to locate PCI Root Bridge IO Protocol: %r\n", Status);
    return Status;
  }

  // Get the PCI bus, device, and function numbers of a device
  Status = PciRootBridgeIo->Pci.Read(PciRootBridgeIo, EfiPciWidthUint16, 0, 0, 0, &Segment);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to read PCI configuration space: %r\n", Status);
    return Status;
  }
  Status = PciRootBridgeIo->Pci.Read(PciRootBridgeIo, EfiPciWidthUint16, 0, 0, 1, &Bus);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to read PCI configuration space: %r\n", Status);
    return Status;
  }
  Status = PciRootBridgeIo->Pci.Read(PciRootBridgeIo, EfiPciWidthUint16, 0, 0, 2, &Device);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to read PCI configuration space: %r\n", Status);
    return Status;
  }
  Status = PciRootBridgeIo->Pci.Read(PciRootBridgeIo, EfiPciWidthUint16, 0, 0, 3, &Function);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to read PCI configuration space: %r\n", Status);
    return Status;
  }

  // Convert the PCI bus, device, and function numbers to a string
  CHAR16 Buffer[32];
  UnicodeSPrint(Buffer, sizeof(Buffer), L"%04x:%02x:%02x.%x", Segment, Bus, Device, Function);

  // Execute the "echo" command with the string as an argument
  CHAR16 Command[64];
  UnicodeSPrint(Command, sizeof(Command), L"echo %s", Buffer);
  Status = ShellExecute(&gEfiShellProtocolGuid, Command, NULL, NULL);
  if (EFI_ERROR(Status)) {
    Print(L"Failed to execute command: %r\n", Status);
    return Status;
  }

  return EFI_SUCCESS;
}

这个代码使用了UnicodeSPrint函数将PCI总线，设备和功能号拼接成一个字符串，然后使用ShellProtocol->Execute函数执行一个“echo”命令，并将字符串作为参数传递给该命令。在实际使用中，您需要替换PCI设备的总线，设备和功能号，并根据需要更改Shell命令。