Merge bitcoin/bitcoin#27636: kernel: Remove util/system from kernel library, interface_ui from validation.

7d3b35004b039f2bd606bb46a540de7babdbc41e refactor: Move system from util to common library (TheCharlatan)
7eee356c0a7fefd70c8de21689efa335f52a69ba refactor: Split util::AnyPtr into its own file (TheCharlatan)
44de325d95447498036479c3112ba741caf45bf6 refactor: Split util::insert into its own file (TheCharlatan)
9ec5da36b62276ae22e348f26f88aaf646357d6d refactor: Move ScheduleBatchPriority to its own file (TheCharlatan)
f871c69191dfe1331861ebcdbadb6bd47e45c8b1 kernel: Add warning method to notifications (TheCharlatan)
4452707edec91c7d7991f486dd41ef3edb4f7fbf kernel: Add progress method to notifications (TheCharlatan)
84d71457e7250ab25c0a11d1ad1c7657197ffd90 kernel: Add headerTip method to notifications (TheCharlatan)
447761c8228d58f948aae7e73ed079c028cacb97 kernel: Add notification interface (TheCharlatan)

Pull request description:

  This pull request is part of the `libbitcoinkernel` project https://github.com/bitcoin/bitcoin/issues/27587 https://github.com/bitcoin/bitcoin/projects/18 and more specifically its "Step 2: Decouple most non-consensus code from libbitcoinkernel".

  ---

  It removes the kernel library's dependency on `util/system` and `interface_ui`. `util/system` contains networking and shell-related code that should not be part of the kernel library. The following pull requests prepared `util/system` for this final step: https://github.com/bitcoin/bitcoin/pull/27419 https://github.com/bitcoin/bitcoin/pull/27254 https://github.com/bitcoin/bitcoin/pull/27238.

  `interface_ui` defines functions for a more general node interface and has a dependency on `boost/signals2`. After applying the patches from this pull request, the kernel's reliance on boost is down to `boost::multiindex`.

  The approach implemented here introduces some indirection, which makes the code a bit harder to read. Any suggestions for improving or reworking this pull request to make it more concise, or even reworking it into a more proper interface, are appreciated.

ACKs for top commit:
  MarcoFalke:
    re-ACK 7d3b35004b039f2bd606bb46a540de7babdbc41e (no change) 🎋
  stickies-v:
    Code Review ACK 7d3b35004b039f2bd606bb46a540de7babdbc41e
  hebasto:
    re-ACK 7d3b35004b039f2bd606bb46a540de7babdbc41e, only last two commits dropped since my [recent](https://github.com/bitcoin/bitcoin/pull/27636#pullrequestreview-1435394620) review.

Tree-SHA512: c8cfc698dc9d78e20191c444708f2d957501229abe95e5806106d1126fb9c5fbcee686fb55645658c0107ce71f10646f37a2fdf7fde16bbf22cbf1ac885dd08d

2 files changed, 145 insertions, 0 deletions

diff --git a/src/common/system.cpp b/src/common/system.cpp
new file mode 100644
index 0000000000..1d1c5fa56a
--- /dev/null
+++ b/src/common/system.cpp
@@ -0,0 +1,107 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <common/system.h>
+
+#include <logging.h>
+#include <util/string.h>
+#include <util/time.h>
+
+#ifndef WIN32
+#include <sys/stat.h>
+#else
+#include <codecvt>
+#endif
+
+#ifdef HAVE_MALLOPT_ARENA_MAX
+#include <malloc.h>
+#endif
+
+#include <cstdlib>
+#include <locale>
+#include <stdexcept>
+#include <string>
+#include <thread>
+
+// Application startup time (used for uptime calculation)
+const int64_t nStartupTime = GetTime();
+
+#ifndef WIN32
+std::string ShellEscape(const std::string& arg)
+{
+    std::string escaped = arg;
+    ReplaceAll(escaped, "'", "'\"'\"'");
+    return "'" + escaped + "'";
+}
+#endif
+
+#if HAVE_SYSTEM
+void runCommand(const std::string& strCommand)
+{
+    if (strCommand.empty()) return;
+#ifndef WIN32
+    int nErr = ::system(strCommand.c_str());
+#else
+    int nErr = ::_wsystem(std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t>().from_bytes(strCommand).c_str());
+#endif
+    if (nErr)
+        LogPrintf("runCommand error: system(%s) returned %d\n", strCommand, nErr);
+}
+#endif
+
+void SetupEnvironment()
+{
+#ifdef HAVE_MALLOPT_ARENA_MAX
+    // glibc-specific: On 32-bit systems set the number of arenas to 1.
+    // By default, since glibc 2.10, the C library will create up to two heap
+    // arenas per core. This is known to cause excessive virtual address space
+    // usage in our usage. Work around it by setting the maximum number of
+    // arenas to 1.
+    if (sizeof(void*) == 4) {
+        mallopt(M_ARENA_MAX, 1);
+    }
+#endif
+    // On most POSIX systems (e.g. Linux, but not BSD) the environment's locale
+    // may be invalid, in which case the "C.UTF-8" locale is used as fallback.
+#if !defined(WIN32) && !defined(MAC_OSX) && !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
+    try {
+        std::locale(""); // Raises a runtime error if current locale is invalid
+    } catch (const std::runtime_error&) {
+        setenv("LC_ALL", "C.UTF-8", 1);
+    }
+#elif defined(WIN32)
+    // Set the default input/output charset is utf-8
+    SetConsoleCP(CP_UTF8);
+    SetConsoleOutputCP(CP_UTF8);
+#endif
+
+#ifndef WIN32
+    constexpr mode_t private_umask = 0077;
+    umask(private_umask);
+#endif
+}
+
+bool SetupNetworking()
+{
+#ifdef WIN32
+    // Initialize Windows Sockets
+    WSADATA wsadata;
+    int ret = WSAStartup(MAKEWORD(2,2), &wsadata);
+    if (ret != NO_ERROR || LOBYTE(wsadata.wVersion ) != 2 || HIBYTE(wsadata.wVersion) != 2)
+        return false;
+#endif
+    return true;
+}
+
+int GetNumCores()
+{
+    return std::thread::hardware_concurrency();
+}
+
+// Obtain the application startup time (used for uptime calculation)
+int64_t GetStartupTime()
+{
+    return nStartupTime;
+}
diff --git a/src/common/system.h b/src/common/system.h
new file mode 100644
index 0000000000..40206aaa01
--- /dev/null
+++ b/src/common/system.h
@@ -0,0 +1,38 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2022 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_COMMON_SYSTEM_H
+#define BITCOIN_COMMON_SYSTEM_H
+
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#include <compat/assumptions.h>
+#include <compat/compat.h>
+
+#include <set>
+#include <stdint.h>
+#include <string>
+
+// Application startup time (used for uptime calculation)
+int64_t GetStartupTime();
+
+void SetupEnvironment();
+bool SetupNetworking();
+#ifndef WIN32
+std::string ShellEscape(const std::string& arg);
+#endif
+#if HAVE_SYSTEM
+void runCommand(const std::string& strCommand);
+#endif
+
+/**
+ * Return the number of cores available on the current system.
+ * @note This does count virtual cores, such as those provided by HyperThreading.
+ */
+int GetNumCores();
+
+#endif // BITCOIN_COMMON_SYSTEM_H