[mirror_edk2.git] / StdLibPrivateInternalFiles / ReadMe.txt

                                     EADK\r
                  EDK II Standard Libraries and Applications\r
                                    ReadMe\r
                                 Version 1.02\r
                                 21 Dec. 2012\r
\r
\r
OVERVIEW\r
========\r
The EADK (uEfi Application Development Kit) provides a set of standards-based\r
libraries, along with utility and demonstration applications, intended to\r
ease development of UEFI applications based upon the EDK II Open-Source\r
distribution.\r
\r
At this time, applications developed with the EADK are intended to reside\r
on, and be loaded from, storage separate from the core firmware.  This is\r
primarily due to size and environmental requirements.\r
\r
This release of the EADK should only be used to produce UEFI Applications.  Due to the execution\r
environment built by the StdLib component, execution as a UEFI driver can cause system stability\r
issues.\r
\r
This document describes the EDK II specific aspects of installing, building,\r
and using the Standard C Library component of the EDK II Application\r
Development Kit, EADK.\r
\r
The EADK is comprised of three packages:\r
        AppPkg, StdLib, and StdLibPrivateInternalFiles.\r
\r
  AppPkg   This package contains applications which demonstrate use of the\r
           Standard C and Sockets Libraries.\r
           These applications reside in AppPkg/Applications.\r
\r
      Enquire  This is a program that determines many properties of the\r
               C compiler and the target machine that Enquire is run on.  The\r
               only changes required to port this 1990s era Unix program to\r
               EDK II were the addition of eight pragmas to enquire.c in\r
               order to disable some Microsoft VC++ specific warnings.\r
\r
      Hello    This is a very simple EDK II native application that doesn't use\r
               any features of the Standard C Library.\r
\r
      Main     This application is functionally identical to Hello, except that\r
               it uses the Standard C Library to provide a main() entry point.\r
\r
      Python   A port of the Python-2.7.2 interpreter for UEFI.  Building this\r
               application is disabled by default.\r
               See the PythonReadMe.txt file, in the Python directory,\r
               for information on configuring and building Python.\r
\r
      Sockets  A collection of applications demonstrating use of the\r
               EDK II Socket Libraries.  These applications include:\r
\r
               *   DataSink                     *   DataSource\r
               *   GetAddrInfo                  *   GetHostByAddr\r
               *   GetHostByDns                 *   GetHostByName\r
               *   GetNetByAddr                 *   GetNetByName\r
               *   GetServByName                *   GetServByPort\r
               *   OobRx                        *   OobTx\r
               *   RawIp4Rx                     *   RawIp4Tx\r
               *   RecvDgram                    *   SetHostName\r
               *   SetSockOpt                   *   TftpServer\r
               *   WebServer\r
\r
  StdLib   The StdLib package contains the standard header files as well as\r
           implementations of other standards-based libraries.\r
\r
           *   BsdSocketLib\r
                  Support routines above the sockets layer and C interface for\r
                  the UEFI socket library.\r
           *   Efi\r
                  Template contents for the target system's\r
                  \Efi\StdLib\etc directory.\r
           *   EfiSocketLib\r
                  UEFI socket implementation, may be linked into an\r
                  application or run as a driver.\r
           *   Include\r
                  Standard include files.\r
           *   LibC\r
                  C Standard Library implementation as per\r
                  ISO/IEC 9899:199409 (C95).\r
           *   PosixLib\r
                  Selected functions from the "Single Unix v4" specification.\r
           *   SocketDxe\r
                  UEFI sockets driver, includes EfiSocketLib.\r
           *   UseSocketDxe\r
                  Alternate linkage for applications that get built into the\r
                  firmware.  Cause application to use a common instance of the\r
                  sockets driver instead of including all of sockets into the\r
                  application.\r
\r
  StdLibPrivateInternalFiles  The contents of this package are for the\r
           exclusive use of the library implementations in StdLib.  Please do\r
           not use anything from this package in your application or else\r
           unexpected behavior may occur.\r
           This package may be removed in a future release.\r
\r
\r
RELEASE NOTES\r
=============\r
  Fixes and Additions\r
  -------------------\r
Beginning with release 1.01, applications built with the StdLib package\r
no longer have a dependency on the TimerLib.\r
\r
  Known Issues\r
  -----------------\r
This release of the EADK has some restrictions, as described below.\r
\r
    1.  The target machine must be running firmware which provides the\r
        UEFI 2.3 HII protocol.\r
\r
    2.  Applications must be launched from within the EFI Shell.\r
\r
    3.  Absolute file paths may optionally be prefixed by a volume specifier\r
        such as "FS0:".  The volume specifier is separated from the remainder\r
        of the path by a single colon ':'.  The volume specifier must be one of\r
        the Shell's mapped volume names as shown by the "map" command.\r
\r
    4.  Absolute file paths that don't begin with a volume specifier;\r
        e.g. paths that begin with "/", are relative to the currently selected\r
        volume.  When the EFI Shell first starts, there is NO selected volume.\r
\r
    5.  The tmpfile(), and related, functions require that the current volume\r
        have a temporary directory as specified in <paths.h>.  This directory\r
        is specified by macro _PATH_TMP as /Efi/StdLib/tmp.\r
\r
The Standard C Library provided by this package is a "hosted" implementation\r
conforming to the ISO/IEC 9899-1990 C Language Standard with Addendum 1. This\r
is commonly referred to as the "C 95" specification or ISO/IEC 9899:199409.\r
The following instructions assume that you have an existing EDK II or UDK 2010\r
source tree that has been configured to build with your tool chain.  For\r
convenience, it is assumed that your EDK II source tree is located at\r
C:\Source\Edk2.\r
\r
\r
EADK INSTALLATION\r
=================\r
The EADK is integrated within the EDK II source tree and is included with\r
current EDK II check-outs.  If they are missing from your tree, they may be\r
installed by extracting, downloading or copying them to the root of your EDK II\r
source tree.  The three package directories should be peers to the Conf,\r
MdePkg, Nt32Pkg, etc. directories.\r
\r
There are some boiler-plate declarations and definitions that need to be\r
included in your application's INF and DSC build files.  These are described\r
in the CONFIGURATION section, below.\r
\r
A subset of the Python 2.7.2 distribution is included as part of AppPkg.  If desired,\r
the full Python 2.7.2 distribution may be downloaded from python.org and used instead.\r
Delete or rename the existing Python-2.7.2 directory then extract the downloaded\r
Python-2.7.2.tgz file into the AppPkg\Applications\Python directory.  This will produce a\r
Python-2.7.2 directory containing the full Python distribution.  Python files that had to be\r
modified for EDK II are in the AppPkg\Applications\Python\PyMod-2.7.2 directory.  These\r
files need to be copied into the corresponding directories within the extracted Python-2.7.2\r
directory before Python can be built.\r
\r
\r
BUILDING\r
========\r
It is not necessary to build the libraries separately from the target\r
application(s). If the application references the libraries, as described in\r
USAGE, below; the required libraries will be built as needed.\r
To build the applications included in AppPkg, one would execute the following\r
commands within the "Visual Studio Command Prompt" window:\r
\r
    > cd C:\Source\Edk2\r
    > .\edksetup.bat\r
    > build -a X64 -p AppPkg\AppPkg.dsc\r
\r
This will produce the application executables: Enquire.efi, Hello.efi, and\r
Main.efi in the C:\Source\Edk2\Build\AppPkg\DEBUG_VS2008\X64 directory; with\r
the DEBUG_VS2008 component being replaced with the actual tool chain and build\r
type you have selected in Conf\Tools_def.txt. These executables can now be\r
loaded onto the target platform and executed.\r
\r
If you examine the AppPkg.dsc file, you will notice that the StdLib package is\r
referenced in order to resolve the library classes comprising the Standard\r
C Library.  This, plus referencing the StdLib package in your application's\r
.inf file is all that is needed to link your application to the standard\r
libraries.\r
\r
Unless explicitly stated as allowed, EADK components should not be added as\r
components of a DSC file which builds a platform's core firmware.  There are\r
incompatibilities in build flags and requirements that will conflict with the\r
requirements of the core firmware.  EADK components should be built using a\r
separate DSC file then, if absolutely necessary, included as binary components\r
of other DSC files.\r
\r
USAGE\r
=====\r
This implementation of the Standard C Library is comprised of 16 separate\r
libraries in addition to the standard header files. Nine of the libraries are\r
associated with use of one of the standard headers; thus, if the header is used\r
in an application, it must be linked with the associated library.  Three\r
libraries are used to provide the Console and File-system device abstractions.\r
The libraries and associated header files are described in the following table.\r
\r
 Library\r
  Class      Header File(s)    Notes\r
----------  ----------------  -------------------------------------------------\r
LibC        -- Use Always --  This library is always required.\r
LibCtype    ctype.h, wctype.h Character classification and mapping\r
LibLocale   locale.h          Localization types, macros, and functions\r
LibMath     math.h            Mathematical functions, types, and macros\r
LibStdio    stdio.h           Standard Input and Output functions, types, and\r
                              macros\r
LibStdLib   stdlib.h          General Utilities for numeric conversion, random\r
                              num., etc.\r
LibString   string.h          String copying, concatenation, comparison,\r
                              & search\r
LibSignal   signal.h          Functions and types for handling run-time\r
                              conditions\r
LibTime     time.h            Time and Date types, macros, and functions\r
LibUefi     sys/EfiSysCall.h  Provides the UEFI system interface and\r
                              "System Calls"\r
LibWchar    wchar.h           Extended multibyte and wide character utilities\r
LibNetUtil                    Network address and number manipulation utilities\r
DevConsole                    Automatically provided File I/O abstractions for\r
                              the UEFI Console device.  No need to list this\r
                              library class in your INF file(s).\r
DevShell    Add if desired    File I/O abstractions using UEFI shell\r
                              facilities.  Add this to the application's main\r
                              INF file if file-system access needed.\r
DevUtility  -- Do Not Use --  Utility functions used internally by the Device abstractions\r
LibGdtoa    -- Do Not Use --  This library is used internally and should not\r
                              need to be explicitly specified by an\r
                              application.  It must be defined as one of the\r
                              available library classes in the application's\r
                              DSC file.\r
\r
                         Table 1:  Standard Libraries\r
                         ============================\r
\r
The DevConsole and DevShell libraries provide device I/O functionality and are treated\r
specially.  DevConsole is automatically included so there is no need to reference it in your\r
application's DSC or INF files.  DevShell must be listed, in your application's INF file in the\r
[LibraryClasses] section, if your application does file I/O.\r
\r
These libraries must be fully described in the [LibraryClasses] section of the\r
application package's DSC file. Then, each individual application needs to\r
specify which libraries to link to by specifying the Library Class, from the\r
above table, in the [LibraryClasses] section of the application's INF file. The\r
AppPkg.dsc, StdLib.dsc, and Enquire.inf files provide good examples of this.\r
More details are in the CONFIGURATION section, below.\r
\r
In order to simplify this process, the [LibraryClasses] definitions, and others, are\r
specified in the StdLib.inc file.  If this file is included in the DSC file, usually at the\r
end, then other DSC file changes or additions are unnecessary.  This is further described in\r
the CONFIGURATION section, below.\r
\r
Within the source files of the application, use of the Standard headers and\r
library functions follow standard C programming practices as formalized by\r
ISO/IEC 9899:1990, with Addendum 1, (C 95) C language specification.\r
\r
\r
BUILD CONFIGURATION\r
===================\r
DSC Files\r
---------\r
\r
All EDK II packages which build applications that use the standard libraries\r
must include some "boilerplate" text in the package's .dsc file.  To make it\r
easier, and to reduce cut-and-paste errors, the "boilerplate" text has been\r
consolidated into a single file, StdLib/StdLib.inc, which can be included in\r
your .dsc file using the !include directive.  The provided AppPkg.dsc and\r
StdLib.dsc files do this on their last line.\r
\r
The "boilerplate" text can be included using a !include directive in the\r
package's .dsc file.  The provided AppPkg.dsc and StdLib.dsc files include\r
the following "boilerplate" text:\r
\r
  ##############################################################################\r
  #\r
  # Specify whether we are running in an emulation environment, or not.\r
  # Define EMULATE if we are, else keep the DEFINE commented out.\r
  #\r
  # DEFINE  EMULATE = 1\r
\r
  ##############################################################################\r
  #\r
  #  Include Boilerplate text required for building with the Standard Libraries.\r
  #\r
  ##############################################################################\r
  !include StdLib/StdLib.inc\r
\r
                      Figure 1: "Boilerplate" Inclusion\r
                      =================================\r
\r
The EMULATE macro must be defined if one desires to do source-level debugging within one of\r
the emulated environments such as NT32Pkg or UnixPkg.\r
\r
The final boilerplate line, in Figure 1, includes the StdLib.inc file.\r
Each section of StdLib/StdLib.inc is described below.\r
\r
If desired, all of the Socket applications, in AppPkg, can be built by including Sockets.inc:\r
\r
  !include AppPkg/Applications/Sockets/Sockets.inc\r
\r
              Figure 2: Socket Applications "Boilerplate" Inclusion\r
              =====================================================\r
\r
\r
Descriptions of the Library Classes comprising the Standard Libraries,\r
as shown in Figure 3: Library Class Descriptions, are provided.\r
\r
  [LibraryClasses]\r
    #\r
    # C Standard Libraries\r
    #\r
    LibC|StdLib/LibC/LibC.inf\r
    LibCType|StdLib/LibC/Ctype/Ctype.inf\r
    LibLocale|StdLib/LibC/Locale/Locale.inf\r
    LibMath|StdLib/LibC/Math/Math.inf\r
    LibSignal|StdLib/LibC/Signal/Signal.inf\r
    LibStdio|StdLib/LibC/Stdio/Stdio.inf\r
    LibStdLib|StdLib/LibC/StdLib/StdLib.inf\r
    LibString|StdLib/LibC/String/String.inf\r
    LibTime|StdLib/LibC/Time/Time.inf\r
    LibUefi|StdLib/LibC/Uefi/Uefi.inf\r
    LibWchar|StdLib/LibC/Wchar/Wchar.inf\r
\r
  # Common Utilities for Networking Libraries\r
    LibNetUtil|StdLib/LibC/NetUtil/NetUtil.inf\r
\r
  # Additional libraries for POSIX functionality.\r
    LibErr|StdLib/PosixLib/Err/LibErr.inf\r
    LibGen|StdLib/PosixLib/Gen/LibGen.inf\r
    LibGlob|StdLib/PosixLib/Glob/LibGlob.inf\r
    LibStringlist|StdLib/PosixLib/Stringlist/LibStringlist.inf\r
\r
  # Libraries for device abstractions within the Standard C Library\r
  # Applications should not directly access any functions defined in these libraries.\r
    LibGdtoa|StdLib/LibC/gdtoa/gdtoa.inf\r
    DevConsole|StdLib/LibC/Uefi/Devices/daConsole.inf\r
    DevShell|StdLib/LibC/Uefi/Devices/daShell.inf\r
    DevUtility|StdLib/LibC/Uefi/Devices/daUtility.inf\r
\r
  [LibraryClasses.ARM.UEFI_APPLICATION]\r
    NULL|ArmPkg/Library/CompilerIntrinsicsLib/CompilerIntrinsicsLib.inf\r
\r
                     Figure 3: Library Class Descriptions\r
                     ====================================\r
\r
\r
The directives in Figure 4: Package Component Descriptions will create\r
instances of the BaseLib and BaseMemoryLib library classes that are built\r
with Link-time-Code-Generation disabled.  This is necessary when using the\r
Microsoft tool chains in order to allow the library's functions to be\r
resolved during the second pass of the linker during Link-Time-Code-Generation\r
of the application.\r
\r
A DXE driver version of the Socket library is also built.\r
\r
  [Components]\r
  # BaseLib and BaseMemoryLib need to be built with the /GL- switch\r
  # when using the Microsoft tool chains.  This is required so that\r
  # the library functions can be resolved during the second pass of\r
  # the linker during link-time-code-generation.\r
  #\r
    MdePkg/Library/BaseLib/BaseLib.inf {\r
      <BuildOptions>\r
        MSFT:*_*_*_CC_FLAGS = /X /Zc:wchar_t /GL-\r
    }\r
    MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf {\r
      <BuildOptions>\r
        MSFT:*_*_*_CC_FLAGS = /X /Zc:wchar_t /GL-\r
    }\r
\r
  ##########\r
  #  Socket Layer\r
  ##########\r
    StdLib/SocketDxe/SocketDxe.inf\r
\r
                    Figure 4: Package Component Descriptions\r
                    ========================================\r
\r
\r
Each compiler assumes, by default, that it will be used with standard libraries\r
and headers provided by the compiler vendor.  Many of these assumptions are\r
incorrect for the UEFI environment.  By including a BuildOptions section, as\r
shown in Figure 5: Package Build Options, these assumptions can be\r
tailored for compatibility with UEFI and the EDK II Standard Libraries.\r
\r
Note that the set of BuildOptions used is determined by the state of the EMULATE macro.\r
\r
  [BuildOptions]\r
  !ifndef $(EMULATE)\r
    # These Build Options are used when building the Standard Libraries to be run\r
    # on real hardware.\r
    INTEL:*_*_IA32_CC_FLAGS  = /Qfreestanding\r
     MSFT:*_*_IA32_CC_FLAGS  = /X /Zc:wchar_t\r
      GCC:*_*_IA32_CC_FLAGS  = -nostdinc -nostdlib\r
\r
  !else\r
    # The Build Options, below, are only used when building the Standard Libraries\r
    # to be run under an emulation environment.\r
    # They disable optimization which facillitates debugging under the Emulation environment.\r
    INTEL:*_*_IA32_CC_FLAGS  = /Od\r
     MSFT:*_*_IA32_CC_FLAGS  = /Od\r
      GCC:*_*_IA32_CC_FLAGS  = -O0\r
\r
                        Figure 5: Package Build Options\r
                        ===============================\r
\r
\r
INF Files\r
=========\r
The INF files for most modules will not require special directives in order to\r
support the Standard Libraries.  The two sections which require attention: LibraryClasses\r
and BuildOptions, are described below.\r
\r
  [LibraryClasses]\r
    UefiLib\r
    LibC\r
    LibString\r
    LibStdio\r
    DevShell\r
\r
                      Figure 6: Module Library Classes\r
                      ================================\r
\r
\r
Modules of type UEFI_APPLICATION that perform file I/O must include library\r
class DevShell.  Including this library class will allow file operations to be\r
handled by the UEFI Shell.  Without this class, only Console I/O is supported.\r
\r
\r
An application's INF file might need to include a [BuildOptions] section\r
specifying additional compiler and linker flags necessary to allow the\r
application to be built. Usually, this section is not needed.  When building\r
code from external sources, though, it may be necessary to disable some\r
warnings or enable/disable some compiler features.\r
\r
 [BuildOptions]\r
  INTEL:*_*_*_CC_FLAGS          = /Qdiag-disable:181,186\r
   MSFT:*_*_*_CC_FLAGS          = /Oi- /wd4018 /wd4131\r
    GCC:*_*_IPF_SYMRENAME_FLAGS = --redefine-syms=Rename.txt\r
\r
                        Figure 7: Module Build Options\r
                        ==============================\r
\r
\r
TARGET-SYSTEM INSTALLATION\r
==========================\r
Applications that use file system features or the Socket library depend upon\r
the existence of a specific directory tree structure on the same volume that\r
the application was loaded from.  This tree structure is described below:\r
\r
    /EFI                      Root of the UEFI system area.\r
     |- /Tools                Directory containing applications.\r
     |- /Boot                 UEFI specified Boot directory.\r
     |- /StdLib               Root of the Standard Libraries sub-tree.\r
         |- /etc              Configuration files used by libraries.\r
         |- /tmp              Temporary files created by tmpfile(), etc.\r
\r
\r
The /Efi/StdLib/etc directory must be manually populated from the StdLib/Efi/etc source\r
directory.\r
\r
IMPLEMENTATION-Specific Features\r
================================\r
It is very strongly recommended that applications not use the long or\r
unsigned long types. The size of these types varies between compilers and is one\r
of the less portable aspects of C. Instead, one should use the UEFI defined\r
types whenever possible. Use of these types, listed below for reference,\r
ensures that the declared objects have unambiguous, explicitly declared, sizes\r
and characteristics.\r
\r
        UINT64   INT64     UINT32   INT32   UINT16   CHAR16\r
        INT16    BOOLEAN   UINT8    CHAR8   INT8\r
        UINTN    INTN                       PHYSICALADDRESS\r
\r
There are similar types declared in sys/types.h and related files.\r
\r
The types UINTN and INTN have the native width of the target processor\r
architecture. Thus, INTN on IA32 has a width of 32 bits while INTN on X64 and\r
IPF has a width of 64 bits.\r
\r
For maximum portability, data objects intended to hold addresses should be\r
declared with type intptr_t or uintptr_t. These types, declared in\r
sys/stdint.h, can be used to create objects capable of holding pointers. Note\r
that these types will generate different sized objects on different processor\r
architectures.  If a constant size across all processors and compilers is\r
needed, use type PHYSICAL_ADDRESS.\r
\r
Though not specifically required by the ISO/IEC 9899 standard, this\r
implementation of the Standard C Library provides the following system calls\r
which are declared in sys/EfiSysCall.h and/or unistd.h.\r
\r
          close   creat    chmod    dup      dup2\r
          fcntl   fstat    getcwd   ioctl    isatty\r
          lseek   lstat    mkdir    open     poll\r
          read    rename   rmdir    stat     unlink   write\r
\r
The open function will accept file names of "stdin:", "stdout:", and "stderr:"\r
which cause the respective streams specified in the UEFI System Table to be\r
opened.  Normally, these are associated with the console device.  When the\r
application is first started, these streams are automatically opened on File\r
Descriptors 0, 1, and 2 respectively.\r
\r
                            # # #\r