diff options
Diffstat (limited to 'OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParser.c')
| -rw-r--r-- | OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParser.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParser.c b/OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParser.c new file mode 100644 index 0000000000..5ca22fcf0d --- /dev/null +++ b/OvmfPkg/Library/QemuFwCfgSimpleParserLib/QemuFwCfgSimpleParser.c @@ -0,0 +1,398 @@ +/** @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
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/QemuFwCfgLib.h>
+#include <Library/QemuFwCfgSimpleParserLib.h>
+
+//
+// Size of the longest valid UINT64 string, including the terminating NUL.
+//
+#define UINT64_STRING_MAX_SIZE \
+ MAX (sizeof "18446744073709551615", sizeof "0xFFFFFFFFFFFFFFFF")
+
+//
+// Size of the longest valid BOOL string (see the "mTrueString" and
+// "mFalseString" arrays below), including the terminating NUL.
+//
+#define BOOL_STRING_MAX_SIZE (sizeof "disabled")
+
+//
+// Length of "\r\n", not including the terminating NUL.
+//
+#define CRLF_LENGTH (sizeof "\r\n" - 1)
+
+//
+// Words recognized as representing TRUE or FALSE.
+//
+STATIC CONST CHAR8 * CONST mTrueString[] = {
+ "true", "yes", "y", "enable", "enabled", "1"
+};
+STATIC CONST CHAR8 * CONST mFalseString[] = {
+ "false", "no", "n", "disable", "disabled", "0"
+};
+
+//
+// Helper functions.
+//
+
+/**
+ Look up FileName with QemuFwCfgFindFile() from QemuFwCfgLib. Read the fw_cfg
+ file into the caller-provided CHAR8 array. NUL-terminate the array.
+
+ @param[in] FileName The name of the fw_cfg file to look up and read.
+
+ @param[in,out] BufferSize On input, number of bytes available in Buffer.
+
+ On output, the number of bytes that have been
+ stored to Buffer.
+
+ On error, BufferSize is indeterminate.
+
+ @param[out] Buffer The buffer to read the fw_cfg file into. If the
+ fw_cfg file contents are not NUL-terminated, then
+ a NUL character is placed into Buffer after the
+ fw_cfg file contents.
+
+ On error, Buffer is indeterminate.
+
+ @retval RETURN_SUCCESS Buffer has been populated with the fw_cfg file
+ contents. Buffer is NUL-terminated regardless
+ of whether the fw_cfg file itself was
+ NUL-terminated.
+
+ @retval RETURN_UNSUPPORTED Firmware configuration is unavailable.
+
+ @retval RETURN_PROTOCOL_ERROR The fw_cfg file does not fit into Buffer.
+ (This is considered a QEMU configuration
+ error; BufferSize is considered authoritative
+ for the contents of the fw_cfg file identified
+ by FileName.)
+
+ @retval RETURN_PROTOCOL_ERROR The fw_cfg file contents are not themselves
+ NUL-terminated, and an extra NUL byte does not
+ fit into Buffer. (Again a QEMU configuration
+ error.)
+
+ @return Error codes propagated from
+ QemuFwCfgFindFile().
+**/
+STATIC
+RETURN_STATUS
+QemuFwCfgGetAsString (
+ IN CONST CHAR8 *FileName,
+ IN OUT UINTN *BufferSize,
+ OUT CHAR8 *Buffer
+ )
+{
+ RETURN_STATUS Status;
+ FIRMWARE_CONFIG_ITEM FwCfgItem;
+ UINTN FwCfgSize;
+
+ if (!QemuFwCfgIsAvailable ()) {
+ return RETURN_UNSUPPORTED;
+ }
+
+ Status = QemuFwCfgFindFile (FileName, &FwCfgItem, &FwCfgSize);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ if (FwCfgSize > *BufferSize) {
+ return RETURN_PROTOCOL_ERROR;
+ }
+
+ QemuFwCfgSelectItem (FwCfgItem);
+ QemuFwCfgReadBytes (FwCfgSize, Buffer);
+
+ //
+ // If Buffer is already NUL-terminated due to fw_cfg contents, we're done.
+ //
+ if (FwCfgSize > 0 && Buffer[FwCfgSize - 1] == '\0') {
+ *BufferSize = FwCfgSize;
+ return RETURN_SUCCESS;
+ }
+ //
+ // Otherwise, append a NUL byte to Buffer (if we have room for it).
+ //
+ if (FwCfgSize == *BufferSize) {
+ return RETURN_PROTOCOL_ERROR;
+ }
+ Buffer[FwCfgSize] = '\0';
+ *BufferSize = FwCfgSize + 1;
+ return RETURN_SUCCESS;
+}
+
+/**
+ Remove a trailing \r\n or \n sequence from a string.
+
+ @param[in,out] BufferSize On input, the number of bytes in Buffer, including
+ the terminating NUL.
+
+ On output, the adjusted string size (including the
+ terminating NUL), after stripping the \r\n or \n
+ suffix.
+
+ @param[in,out] Buffer The NUL-terminated string to trim.
+**/
+STATIC
+VOID
+StripNewline (
+ IN OUT UINTN *BufferSize,
+ IN OUT CHAR8 *Buffer
+ )
+{
+ UINTN InSize, OutSize;
+
+ InSize = *BufferSize;
+ OutSize = InSize;
+
+ if (InSize >= 3 &&
+ Buffer[InSize - 3] == '\r' && Buffer[InSize - 2] == '\n') {
+ OutSize = InSize - 2;
+ } else if (InSize >= 2 && Buffer[InSize - 2] == '\n') {
+ OutSize = InSize - 1;
+ }
+
+ if (OutSize < InSize) {
+ Buffer[OutSize - 1] = '\0';
+ *BufferSize = OutSize;
+ }
+}
+
+/**
+ Read the fw_cfg file identified by FileName as a string into a small array
+ with automatic storage duration, using QemuFwCfgGetAsString(). Parse the
+ string as a UINT64. Perform a range-check on the parsed value.
+
+ @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[in] Limit The inclusive upper bound on the parsed UINT64 value.
+
+ @param[out] Value On success, Value has been parsed with the BaseLib
+ function determined by ParseAsHex, and has been
+ range-checked against [0, Limit].
+
+ 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, Limit] 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.
+**/
+STATIC
+RETURN_STATUS
+QemuFwCfgParseUint64WithLimit (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ IN UINT64 Limit,
+ OUT UINT64 *Value
+ )
+{
+ UINTN Uint64StringSize;
+ CHAR8 Uint64String[UINT64_STRING_MAX_SIZE + CRLF_LENGTH];
+ RETURN_STATUS Status;
+ CHAR8 *EndPointer;
+ UINT64 Uint64;
+
+ Uint64StringSize = sizeof Uint64String;
+ Status = QemuFwCfgGetAsString (FileName, &Uint64StringSize, Uint64String);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+
+ StripNewline (&Uint64StringSize, Uint64String);
+
+ if (ParseAsHex) {
+ Status = AsciiStrHexToUint64S (Uint64String, &EndPointer, &Uint64);
+ } else {
+ Status = AsciiStrDecimalToUint64S (Uint64String, &EndPointer, &Uint64);
+ }
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+
+ //
+ // Report a wire protocol error if the subject sequence is empty, or trailing
+ // garbage is present, or Limit is not honored.
+ //
+ if (EndPointer == Uint64String || *EndPointer != '\0' || Uint64 > Limit) {
+ return RETURN_PROTOCOL_ERROR;
+ }
+
+ *Value = Uint64;
+ return RETURN_SUCCESS;
+}
+
+//
+// Public functions.
+//
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgSimpleParserInit (
+ VOID
+ )
+{
+ //
+ // Do nothing, just participate in constructor dependency ordering.
+ //
+ return RETURN_SUCCESS;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseBool (
+ IN CONST CHAR8 *FileName,
+ OUT BOOLEAN *Value
+ )
+{
+ UINTN BoolStringSize;
+ CHAR8 BoolString[BOOL_STRING_MAX_SIZE + CRLF_LENGTH];
+ RETURN_STATUS Status;
+ UINTN Idx;
+
+ BoolStringSize = sizeof BoolString;
+ Status = QemuFwCfgGetAsString (FileName, &BoolStringSize, BoolString);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+
+ StripNewline (&BoolStringSize, BoolString);
+
+ for (Idx = 0; Idx < ARRAY_SIZE (mTrueString); ++Idx) {
+ if (AsciiStriCmp (BoolString, mTrueString[Idx]) == 0) {
+ *Value = TRUE;
+ return RETURN_SUCCESS;
+ }
+ }
+
+ for (Idx = 0; Idx < ARRAY_SIZE (mFalseString); ++Idx) {
+ if (AsciiStriCmp (BoolString, mFalseString[Idx]) == 0) {
+ *Value = FALSE;
+ return RETURN_SUCCESS;
+ }
+ }
+
+ return RETURN_PROTOCOL_ERROR;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint8 (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ OUT UINT8 *Value
+ )
+{
+ RETURN_STATUS Status;
+ UINT64 Uint64;
+
+ Status = QemuFwCfgParseUint64WithLimit (FileName, ParseAsHex, MAX_UINT8,
+ &Uint64);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ *Value = (UINT8)Uint64;
+ return RETURN_SUCCESS;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint16 (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ OUT UINT16 *Value
+ )
+{
+ RETURN_STATUS Status;
+ UINT64 Uint64;
+
+ Status = QemuFwCfgParseUint64WithLimit (FileName, ParseAsHex, MAX_UINT16,
+ &Uint64);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ *Value = (UINT16)Uint64;
+ return RETURN_SUCCESS;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint32 (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ OUT UINT32 *Value
+ )
+{
+ RETURN_STATUS Status;
+ UINT64 Uint64;
+
+ Status = QemuFwCfgParseUint64WithLimit (FileName, ParseAsHex, MAX_UINT32,
+ &Uint64);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ *Value = (UINT32)Uint64;
+ return RETURN_SUCCESS;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUint64 (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ OUT UINT64 *Value
+ )
+{
+ RETURN_STATUS Status;
+ UINT64 Uint64;
+
+ Status = QemuFwCfgParseUint64WithLimit (FileName, ParseAsHex, MAX_UINT64,
+ &Uint64);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ *Value = Uint64;
+ return RETURN_SUCCESS;
+}
+
+RETURN_STATUS
+EFIAPI
+QemuFwCfgParseUintn (
+ IN CONST CHAR8 *FileName,
+ IN BOOLEAN ParseAsHex,
+ OUT UINTN *Value
+ )
+{
+ RETURN_STATUS Status;
+ UINT64 Uint64;
+
+ Status = QemuFwCfgParseUint64WithLimit (FileName, ParseAsHex, MAX_UINTN,
+ &Uint64);
+ if (RETURN_ERROR (Status)) {
+ return Status;
+ }
+ *Value = (UINTN)Uint64;
+ return RETURN_SUCCESS;
+}
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