OvmfPkg: introduce QemuFwCfgSimpleParserLib

We already parse some boolean and integer values from named fw_cfg files (usually into PCDs), and we're going to cover more. Add a dedicated library for centralizing the parsing logic. Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Per Sundstrom <per_sundstrom@yahoo.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2681 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20200424075353.8489-2-lersek@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
2020-04-24 09:53:47 +02:00
parent 64ab457d1f
commit 611c7f1101
7 changed files with 560 additions and 0 deletions
--- a/OvmfPkg/Include/Library/QemuFwCfgSimpleParserLib.h
+++ b/OvmfPkg/Include/Library/QemuFwCfgSimpleParserLib.h
@ -0,0 +1,128 @@
+/** @file
+  Parse the contents of named fw_cfg files as simple (scalar) data types.
+
+  Copyright (C) 2020, Red Hat, Inc.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef QEMU_FW_CFG_SIMPLE_PARSER_LIB_H_
+#define QEMU_FW_CFG_SIMPLE_PARSER_LIB_H_
+
+#include <Base.h>
+
+/**
+  Look up FileName with QemuFwCfgFindFile() from QemuFwCfgLib. Read the fw_cfg
+  file into a small array with automatic storage duration. Parse the array as
+  the textual representation of a BOOLEAN.
+
+  @param[in] FileName  The name of the fw_cfg file to look up and parse.
+
+  @param[out] Value    On success, Value is TRUE if the contents of the fw_cfg
+                       file case-insensitively match "true", "yes", "y",
+                       "enable", "enabled", "1".
+
+                       On success, Value is FALSE if the contents of the fw_cfg
+                       file case-insensitively match "false", "no", "n",
+                       "disable", "disabled", "0".
+
+                       On failure, Value is not changed.
+
+  @retval RETURN_SUCCESS         Parsing successful. Value has been set.
+
+  @retval RETURN_UNSUPPORTED     Firmware configuration is unavailable.
+
+  @retval RETURN_PROTOCOL_ERROR  Parsing failed. Value has not been changed.
+
+  @return                        Error codes propagated from
+                                 QemuFwCfgFindFile(). Value has not been
+                                 changed.
+**/
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseBool (
+  IN  CONST CHAR8 *FileName,
+  OUT BOOLEAN     *Value
+  );
+
+/**
+  Look up FileName with QemuFwCfgFindFile() from QemuFwCfgLib. Read the fw_cfg
+  file into a small array with automatic storage duration. Parse the array as
+  the textual representation of a UINT8.
+
+  @param[in] FileName    The name of the fw_cfg file to look up and parse.
+
+  @param[in] ParseAsHex  If TRUE, call BaseLib's AsciiStrHexToUint64S() for
+                         parsing the fw_cfg file.
+
+                         If FALSE, call BaseLib's AsciiStrDecimalToUint64S()
+                         for parsing the fw_cfg file.
+
+  @param[out] Value      On success, Value has been parsed with the BaseLib
+                         function determined by ParseAsHex, and also
+                         range-checked for [0, MAX_UINT8].
+
+                         On failure, Value is not changed.
+
+  @retval RETURN_SUCCESS         Parsing successful. Value has been set.
+
+  @retval RETURN_UNSUPPORTED     Firmware configuration is unavailable.
+
+  @retval RETURN_PROTOCOL_ERROR  Parsing failed. Value has not been changed.
+
+  @retval RETURN_PROTOCOL_ERROR  Parsing succeeded, but the result does not fit
+                                 in the [0, MAX_UINT8] range. Value has not
+                                 been changed.
+
+  @return                        Error codes propagated from
+                                 QemuFwCfgFindFile() and from the BaseLib
+                                 function selected by ParseAsHex. Value has not
+                                 been changed.
+**/
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint8 (
+  IN  CONST CHAR8 *FileName,
+  IN  BOOLEAN     ParseAsHex,
+  OUT UINT8       *Value
+  );
+
+//
+// The following functions behave identically to QemuFwCfgParseUint8(),
+// only their range checks use MAX_UINT16, MAX_UINT32, MAX_UINT64, MAX_UINTN,
+// respectively.
+//
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint16 (
+  IN  CONST CHAR8 *FileName,
+  IN  BOOLEAN     ParseAsHex,
+  OUT UINT16      *Value
+  );
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint32 (
+  IN  CONST CHAR8 *FileName,
+  IN  BOOLEAN     ParseAsHex,
+  OUT UINT32      *Value
+  );
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint64 (
+  IN  CONST CHAR8 *FileName,
+  IN  BOOLEAN     ParseAsHex,
+  OUT UINT64      *Value
+  );
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUintn (
+  IN  CONST CHAR8 *FileName,
+  IN  BOOLEAN     ParseAsHex,
+  OUT UINTN       *Value
+  );
+
+#endif // QEMU_FW_CFG_SIMPLE_PARSER_LIB_H_