[Sapling] init zk-snarks params.

furszy · furszy · commit da60be287155 · 2020-08-02T23:03:37.000-03:00
diff --git a/src/sapling/util.cpp b/src/sapling/util.cpp
@@ -4,8 +4,110 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "sapling/util.h"
+#include "sync.h"
 #include <algorithm>
+#include <librustzcash.h>
 #include <stdexcept>
+#include <iostream>
+
+static boost::filesystem::path zc_paramsPathCached;
+static RecursiveMutex csPathCached;
+
+static boost::filesystem::path ZC_GetBaseParamsDir()
+{
+    // Copied from GetDefaultDataDir and adapter for zcash params.
+
+    namespace fs = boost::filesystem;
+    // Windows < Vista: C:\Documents and Settings\Username\Application Data\ZcashParams
+    // Windows >= Vista: C:\Users\Username\AppData\Roaming\ZcashParams
+    // Mac: ~/Library/Application Support/ZcashParams
+    // Unix: ~/.zcash-params
+#ifdef WIN32
+    // Windows
+    return GetSpecialFolderPath(CSIDL_APPDATA) / "ZcashParams";
+#else
+    fs::path pathRet;
+    char* pszHome = getenv("HOME");
+    if (pszHome == NULL || strlen(pszHome) == 0)
+        pathRet = fs::path("/");
+    else
+        pathRet = fs::path(pszHome);
+#ifdef MAC_OSX
+    // Mac
+    pathRet /= "Library/Application Support";
+    TryCreateDirectory(pathRet);
+    return pathRet / "ZcashParams";
+#else
+    // Unix
+    return pathRet / ".zcash-params";
+#endif
+#endif
+}
+
+const boost::filesystem::path &ZC_GetParamsDir()
+{
+    namespace fs = boost::filesystem;
+
+    LOCK(csPathCached); // Reuse the same lock as upstream.
+
+    fs::path &path = zc_paramsPathCached;
+
+    // This can be called during exceptions by LogPrintf(), so we cache the
+    // value so we don't have to do memory allocations after that.
+    if (!path.empty())
+        return path;
+
+    path = ZC_GetBaseParamsDir();
+
+    return path;
+}
+
+/**
+ * Ignores exceptions thrown by Boost's create_directory if the requested directory exists.
+ * Specifically handles case where path p exists, but it wasn't possible for the user to
+ * write to the parent directory.
+ */
+bool TryCreateDirectory(const boost::filesystem::path& p)
+{
+    try {
+        return boost::filesystem::create_directory(p);
+    } catch (const boost::filesystem::filesystem_error&) {
+        if (!boost::filesystem::exists(p) || !boost::filesystem::is_directory(p))
+            throw;
+    }
+
+    // create_directory didn't create the directory, it had to have existed already
+    return false;
+}
+
+void initZKSNARKS()
+{
+    boost::filesystem::path sapling_spend = ZC_GetParamsDir() / "sapling-spend.params";
+    boost::filesystem::path sapling_output = ZC_GetParamsDir() / "sapling-output.params";
+    boost::filesystem::path sprout_groth16 = ZC_GetParamsDir() / "sprout-groth16.params";
+
+    if (!(boost::filesystem::exists(sapling_spend) &&
+          boost::filesystem::exists(sapling_output) &&
+          boost::filesystem::exists(sprout_groth16)
+    )) {
+        throw std::runtime_error("Sapling params don't exist");
+    }
+
+    std::string sapling_spend_str = sapling_spend.string();
+    std::string sapling_output_str = sapling_output.string();
+    std::string sprout_groth16_str = sprout_groth16.string();
+
+    librustzcash_init_zksnark_params(
+            sapling_spend_str.c_str(),
+            "8270785a1a0d0bc77196f000ee6d221c9c9894f55307bd9357c3f0105d31ca63991ab91324160d8f53e2bbd3c2633a6eb8bdf5205d822e7f3f73edac51b2b70c",
+            sapling_output_str.c_str(),
+            "657e3d38dbb5cb5e7dd2970e8b03d69b4787dd907285b5a7f0790dcc8072f60bf593b32cc2d1c030e00ff5ae64bf84c5c3beb84ddc841d48264b4a171744d028",
+            sprout_groth16_str.c_str(),
+            "e9b238411bd6c0ec4791e9d04245ec350c9c5744f5610dfcce4365d5ca49dfefd5054e371842b3f88fa1b9d7e8e075249b3ebabd167fa8b0f3161292d36c180a"
+    );
+
+    std::cout << "### Sapling params initialized ###" << std::endl;
+}
 
 std::vector<unsigned char> convertIntToVectorLE(const uint64_t val_int) {
     std::vector<unsigned char> bytes;
diff --git a/src/sapling/util.h b/src/sapling/util.h
@@ -8,11 +8,20 @@
 
 #include "sapling/uint252.h"
 #include "uint256.h"
-#include <sodium.h>
 
+#include <sodium.h>
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
 #include <vector>
 #include <cstdint>
 
+// Init sapling library
+void initZKSNARKS();
+
+// Sapling network dir
+const boost::filesystem::path &ZC_GetParamsDir();
+bool TryCreateDirectory(const boost::filesystem::path& p);
+
 std::vector<unsigned char> convertIntToVectorLE(const uint64_t val_int);
 std::vector<bool> convertBytesVectorToVector(const std::vector<unsigned char>& bytes);
 uint64_t convertVectorToInt(const std::vector<bool>& v);
