loader/util: fully implement zstd bic variant

Implement both compression and decompression utilities and simplify loader logic

libraries/libstratosphere/source/util/util_compression.cpp

@@ -15,6 +15,9 @@
  */
 #include <stratosphere.hpp>
 #include "lz4.h"
+#define ZSTD_STATIC_LINKING_ONLY
+#define ZSTD_ZBIC_SUPPORT 1
+#include "zstd.h"
 
 namespace ams::util {
 
@@ -27,6 +30,23 @@ namespace ams::util {
         /* This is just a thin wrapper around LZ4. */
         return LZ4_compress_default(reinterpret_cast<const char *>(src), reinterpret_cast<char *>(dst), static_cast<int>(src_size), static_cast<int>(dst_size));
     }
+    
+    size_t CompressZstd(void *dst, size_t dst_size, const void *src, size_t src_size) {
+        /* Basic size checks. */
+        AMS_ABORT_UNLESS(dst_size <= std::numeric_limits<int>::max());
+        AMS_ABORT_UNLESS(src_size <= std::numeric_limits<int>::max());
+        
+        /* Additionally, we must check the compression boundary. */ 
+        auto bound = ZSTD_compressBound(src_size);
+        AMS_ABORT_UNLESS(!ZSTD_isError(bound));
+        AMS_ABORT_UNLESS(dst_size >= bound);
+
+        /* Use Zstd default level. */
+        int compressionLevel = 3;
+        
+        /* This is just a wrapper around Zstd. */
+        return ZSTD_compress(dst, dst_size, src, src_size, compressionLevel);
+    }
 
     /* Decompression utilities. */
     int DecompressLZ4(void *dst, size_t dst_size, const void *src, size_t src_size) {
@@ -37,5 +57,54 @@ namespace ams::util {
         /* This is just a thin wrapper around LZ4. */
         return LZ4_decompress_safe(reinterpret_cast<const char *>(src), reinterpret_cast<char *>(dst), static_cast<int>(src_size), static_cast<int>(dst_size));
     }
+    
+    size_t DecompressZstd(void *dst, size_t dst_size, const void *src, size_t src_size) {
+        /* Basic size checks. */
+        AMS_ABORT_UNLESS(dst_size <= std::numeric_limits<int>::max());
+        AMS_ABORT_UNLESS(src_size <= std::numeric_limits<int>::max());
+        
+        /* Additionally, we must check the decompression boundary. */ 
+        auto bound = ZSTD_decompressBound(src, src_size);
+        AMS_ABORT_UNLESS(!ZSTD_isError(bound));
+        AMS_ABORT_UNLESS(dst_size >= bound);
+        
+        /* This is just a wrapper around Zstd. */
+        return ZSTD_decompress(dst, dst_size, src, src_size);
+    }
+    
+    bool DecompressZstdForLoader(void* workspace, size_t workspace_size, void *dst, size_t dst_size, size_t expected_dec_size, const void *src, size_t src_size) {
+        /* Check decompression margin. */
+        auto margin = ZSTD_decompressionMargin(src, src_size);
+        if (ZSTD_isError(margin)) {
+            return false;
+        }
+        
+        /* Don't overflow from margin. */
+        if (!util::CanAddWithoutOverflow(margin, expected_dec_size)) {
+            return false;
+        }
+        
+        /* Make sure we fit in the destination buffer. */
+        if (margin + expected_dec_size > dst_size) {
+            return false;
+        }
+        
+        /* This is a runtime assert in Loader code. We replicate it here. */
+        AMS_ABORT_UNLESS(ZSTD_estimateDCtxSize() == workspace_size);
+        
+        /* Decompress using a static decompression context. */
+        auto dctx = ZSTD_initStaticDCtx(workspace, workspace_size);
+        size_t dec_size = ZSTD_decompressDCtx(dctx, dst, dst_size, src, src_size);
+
+        if (ZSTD_isError(dec_size)) {
+            return false;
+        }
+        
+        if (dec_size != expected_dec_size) {
+            return false;
+        }
+        
+        return true;
+    }
 
 }

libraries/libstratosphere/source/util/zstd_errors.h

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#ifndef ZSTD_ERRORS_H_398273423
+#define ZSTD_ERRORS_H_398273423
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+/* =====   ZSTDERRORLIB_API : control library symbols visibility   ===== */
+#ifndef ZSTDERRORLIB_VISIBLE
+   /* Backwards compatibility with old macro name */
+#  ifdef ZSTDERRORLIB_VISIBILITY
+#    define ZSTDERRORLIB_VISIBLE ZSTDERRORLIB_VISIBILITY
+#  elif defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__)
+#    define ZSTDERRORLIB_VISIBLE __attribute__ ((visibility ("default")))
+#  else
+#    define ZSTDERRORLIB_VISIBLE
+#  endif
+#endif
+
+#ifndef ZSTDERRORLIB_HIDDEN
+#  if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__)
+#    define ZSTDERRORLIB_HIDDEN __attribute__ ((visibility ("hidden")))
+#  else
+#    define ZSTDERRORLIB_HIDDEN
+#  endif
+#endif
+
+#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
+#  define ZSTDERRORLIB_API __declspec(dllexport) ZSTDERRORLIB_VISIBLE
+#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
+#  define ZSTDERRORLIB_API __declspec(dllimport) ZSTDERRORLIB_VISIBLE /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
+#else
+#  define ZSTDERRORLIB_API ZSTDERRORLIB_VISIBLE
+#endif
+
+/*-*********************************************
+ *  Error codes list
+ *-*********************************************
+ *  Error codes _values_ are pinned down since v1.3.1 only.
+ *  Therefore, don't rely on values if you may link to any version < v1.3.1.
+ *
+ *  Only values < 100 are considered stable.
+ *
+ *  note 1 : this API shall be used with static linking only.
+ *           dynamic linking is not yet officially supported.
+ *  note 2 : Prefer relying on the enum than on its value whenever possible
+ *           This is the only supported way to use the error list < v1.3.1
+ *  note 3 : ZSTD_isError() is always correct, whatever the library version.
+ **********************************************/
+typedef enum {
+  ZSTD_error_no_error = 0,
+  ZSTD_error_GENERIC  = 1,
+  ZSTD_error_prefix_unknown                = 10,
+  ZSTD_error_version_unsupported           = 12,
+  ZSTD_error_frameParameter_unsupported    = 14,
+  ZSTD_error_frameParameter_windowTooLarge = 16,
+  ZSTD_error_corruption_detected = 20,
+  ZSTD_error_checksum_wrong      = 22,
+  ZSTD_error_literals_headerWrong = 24,
+  ZSTD_error_dictionary_corrupted      = 30,
+  ZSTD_error_dictionary_wrong          = 32,
+  ZSTD_error_dictionaryCreation_failed = 34,
+  ZSTD_error_parameter_unsupported   = 40,
+  ZSTD_error_parameter_combination_unsupported = 41,
+  ZSTD_error_parameter_outOfBound    = 42,
+  ZSTD_error_tableLog_tooLarge       = 44,
+  ZSTD_error_maxSymbolValue_tooLarge = 46,
+  ZSTD_error_maxSymbolValue_tooSmall = 48,
+  ZSTD_error_cannotProduce_uncompressedBlock = 49,
+  ZSTD_error_stabilityCondition_notRespected = 50,
+  ZSTD_error_stage_wrong       = 60,
+  ZSTD_error_init_missing      = 62,
+  ZSTD_error_memory_allocation = 64,
+  ZSTD_error_workSpace_tooSmall= 66,
+  ZSTD_error_dstSize_tooSmall = 70,
+  ZSTD_error_srcSize_wrong    = 72,
+  ZSTD_error_dstBuffer_null   = 74,
+  ZSTD_error_noForwardProgress_destFull = 80,
+  ZSTD_error_noForwardProgress_inputEmpty = 82,
+  /* following error codes are __NOT STABLE__, they can be removed or changed in future versions */
+  ZSTD_error_frameIndex_tooLarge = 100,
+  ZSTD_error_seekableIO          = 102,
+  ZSTD_error_dstBuffer_wrong     = 104,
+  ZSTD_error_srcBuffer_wrong     = 105,
+  ZSTD_error_sequenceProducer_failed = 106,
+  ZSTD_error_externalSequences_invalid = 107,
+  ZSTD_error_maxCode = 120  /* never EVER use this value directly, it can change in future versions! Use ZSTD_isError() instead */
+} ZSTD_ErrorCode;
+
+ZSTDERRORLIB_API const char* ZSTD_getErrorString(ZSTD_ErrorCode code);   /**< Same as ZSTD_getErrorName, but using a `ZSTD_ErrorCode` enum argument */
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* ZSTD_ERRORS_H_398273423 */