From 9657ce4219c732070987c6feb513f7d606a94c54 Mon Sep 17 00:00:00 2001
From: Kittywhiskers Van Gogh <63189531+kittywhiskers@users.noreply.github.com>
Date: Mon, 1 Feb 2021 13:35:28 +0100
Subject: [PATCH] merge #21052: Replace fs::unique_path with
 GetUniquePath(path) calls

---
 src/Makefile.am            |  2 ++
 src/test/fs_tests.cpp      | 18 +++++++++++++++++-
 src/test/util_tests.cpp    |  3 ++-
 src/util/getuniquepath.cpp | 10 ++++++++++
 src/util/getuniquepath.h   | 19 +++++++++++++++++++
 src/util/system.cpp        |  3 ++-
 6 files changed, 52 insertions(+), 3 deletions(-)
 create mode 100644 src/util/getuniquepath.cpp
 create mode 100644 src/util/getuniquepath.h

diff --git a/src/Makefile.am b/src/Makefile.am
index 065258d2e8d72e..519c3be9205152 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -269,6 +269,7 @@ BITCOIN_CORE_H = \
   util/fees.h \
   util/system.h \
   util/asmap.h \
+  util/getuniquepath.h \
   util/macros.h \
   util/memory.h \
   util/moneystr.h \
@@ -610,6 +611,7 @@ libdash_util_a_SOURCES = \
   util/error.cpp \
   util/fees.cpp \
   util/sock.cpp \
+  util/getuniquepath.cpp \
   util/system.cpp \
   util/asmap.cpp \
   util/moneystr.cpp \
diff --git a/src/test/fs_tests.cpp b/src/test/fs_tests.cpp
index 6e9aed48d5640c..302ae4055f7f6b 100644
--- a/src/test/fs_tests.cpp
+++ b/src/test/fs_tests.cpp
@@ -4,6 +4,7 @@
 //
 #include <fs.h>
 #include <test/test_dash.h>
+#include <util/getuniquepath.h>
 
 #include <boost/test/unit_test.hpp>
 
@@ -51,6 +52,21 @@ BOOST_AUTO_TEST_CASE(fsbridge_fstream)
         file >> input_buffer;
         BOOST_CHECK_EQUAL(input_buffer, "bitcoin");
     }
+    {
+        fs::path p1 = GetUniquePath(tmpfolder);
+        fs::path p2 = GetUniquePath(tmpfolder);
+        fs::path p3 = GetUniquePath(tmpfolder);
+
+        // Ensure that the parent path is always the same.
+        BOOST_CHECK_EQUAL(tmpfolder, p1.parent_path());
+        BOOST_CHECK_EQUAL(tmpfolder, p2.parent_path());
+        BOOST_CHECK_EQUAL(tmpfolder, p3.parent_path());
+
+        // Ensure that generated paths are actually different.
+        BOOST_CHECK(p1 != p2);
+        BOOST_CHECK(p2 != p3);
+        BOOST_CHECK(p1 != p3);
+    }
 }
 
-BOOST_AUTO_TEST_SUITE_END()
+BOOST_AUTO_TEST_SUITE_END()
\ No newline at end of file
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 3ca78f6d546327..57b5135b91b1f6 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -7,6 +7,7 @@
 #include <clientversion.h>
 #include <primitives/transaction.h>
 #include <sync.h>
+#include <util/getuniquepath.h>
 #include <util/strencodings.h>
 #include <util/string.h>
 #include <util/moneystr.h>
@@ -1175,7 +1176,7 @@ BOOST_AUTO_TEST_CASE(test_DirIsWritable)
     BOOST_CHECK_EQUAL(DirIsWritable(tmpdirname), true);
 
     // Should not be able to write to a non-existent dir.
-    tmpdirname = tmpdirname / fs::unique_path();
+    tmpdirname = GetUniquePath(tmpdirname);
     BOOST_CHECK_EQUAL(DirIsWritable(tmpdirname), false);
 
     fs::create_directory(tmpdirname);
diff --git a/src/util/getuniquepath.cpp b/src/util/getuniquepath.cpp
new file mode 100644
index 00000000000000..9839d2f6246e57
--- /dev/null
+++ b/src/util/getuniquepath.cpp
@@ -0,0 +1,10 @@
+#include <random.h>
+#include <fs.h>
+#include <util/strencodings.h>
+
+fs::path GetUniquePath(const fs::path& base)
+{
+    FastRandomContext rnd;
+    fs::path tmpFile = base / HexStr(rnd.randbytes(8));
+    return tmpFile;
+}
\ No newline at end of file
diff --git a/src/util/getuniquepath.h b/src/util/getuniquepath.h
new file mode 100644
index 00000000000000..e0c6147876b6d8
--- /dev/null
+++ b/src/util/getuniquepath.h
@@ -0,0 +1,19 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_GETUNIQUEPATH_H
+#define BITCOIN_UTIL_GETUNIQUEPATH_H
+
+#include <fs.h>
+
+/**
+ * Helper function for getting a unique path
+ *
+ * @param[in] base  Base path
+ * @returns base joined with a random 8-character long string.
+ * @post Returned path is unique with high probability.
+ */
+fs::path GetUniquePath(const fs::path& base);
+
+#endif // BITCOIN_UTIL_GETUNIQUEPATH_H
\ No newline at end of file
diff --git a/src/util/system.cpp b/src/util/system.cpp
index 46dc8c6d368298..455eb2dfe9114c 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -12,6 +12,7 @@
 #include <random.h>
 #include <serialize.h>
 #include <stacktraces.h>
+#include <util/getuniquepath.h>
 #include <util/strencodings.h>
 
 #include <stdarg.h>
@@ -190,7 +191,7 @@ void ReleaseDirectoryLocks()
 
 bool DirIsWritable(const fs::path& directory)
 {
-    fs::path tmpFile = directory / fs::unique_path();
+    fs::path tmpFile = GetUniquePath(directory);
 
     FILE* file = fsbridge::fopen(tmpFile, "a");
     if (!file) return false;