system: add helper for fetching total system memory
What the developer wrote
Authored by Lőrinc
system: add helper for fetching total system memory
Added a minimal system helper to query total physical RAM on [Linux/macOS/Windows](https://stackoverflow.com/a/2513561) (on other platforms we just return an empty optional).
The added test checks if the value is roughly correct by checking if the CI platforms are returning any value and if the value is at least 1 GiB and not more than 10 TiB.
The max value is only validated on 64 bits, since it's not unreasonable for 32 bits to have max memory, but on 64 bits it's likely an error.
https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/ns-sysinfoapi-memorystatusex
> ullTotalPhys The amount of actual physical memory, in bytes.
https://man7.org/linux/man-pages/man3/sysconf.3.html:
> _SC_PHYS_PAGES The number of pages of physical memory. Note that it is possible for the product of this value and the value of _SC_PAGESIZE to overflow.
> _SC_PAGESIZE Size of a page in bytes. Must not be less than 1.
See https://godbolt.org/z/ec81Tjvrj for further details
What changed, and why it matters
This commit adds a simple helper function that asks the operating system how much total physical memory (RAM) the computer has. It supports Linux, macOS, and Windows, and returns no value on other platforms. It also adds a test to make sure the reported number looks reasonable. There is no security issue visible in this change.
No security action needed. This is a benign utility addition. Normal code-review approval is sufficient.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch introduces GetTotalRAM() in src/common/system.cpp/.h. On Windows it uses GlobalMemoryStatusEx(MEMORYSTATUSEX.ullTotalPhys); on Linux/macOS it uses sysconf(_SC_PHYS_PAGES) * sysconf(_SC_PAGESIZE). The result is clamped to size_t max and returned as std::optional
Changed components
src/common/system.cppsrc/common/system.hsrc/test/system_tests.cppInspect captured patch +40 / −4
diff --git a/src/common/system.cpp b/src/common/system.cpp
index 7af792db..cf032adf 100644
--- a/src/common/system.cpp
+++ b/src/common/system.cpp
@@ -11,19 +11,25 @@
#include <util/string.h>
#include <util/time.h>
-#ifndef WIN32
-#include <sys/stat.h>
-#else
-#include <compat/compat.h>
+#ifdef WIN32
#include <codecvt>
+#include <compat/compat.h>
+#include <windows.h>
+#else
+#include <sys/stat.h>
+#include <unistd.h>
#endif
#ifdef HAVE_MALLOPT_ARENA_MAX
#include <malloc.h>
#endif
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
#include <cstdlib>
#include <locale>
+#include <optional>
#include <stdexcept>
#include <string>
#include <thread>
@@ -105,6 +111,17 @@ int GetNumCores()
return std::thread::hardware_concurrency();
}
+std::optional<size_t> GetTotalRAM()
+{
+ auto clamp{[](uint64_t v) { return size_t(std::min(v, uint64_t{std::numeric_limits<size_t>::max()})); }};
+#ifdef WIN32
+ if (MEMORYSTATUSEX m{}; (m.dwLength = sizeof(m), GlobalMemoryStatusEx(&m))) return clamp(m.ullTotalPhys);
+#elif defined(__linux__) || defined(__APPLE__)
+ if (long p{sysconf(_SC_PHYS_PAGES)}, s{sysconf(_SC_PAGESIZE)}; p > 0 && s > 0) return clamp(1ULL * p * s);
+#endif
+ return std::nullopt;
+}
+
// Obtain the application startup time (used for uptime calculation)
int64_t GetStartupTime()
{
diff --git a/src/common/system.h b/src/common/system.h
index a4b56be9..2184f1d4 100644
--- a/src/common/system.h
+++ b/src/common/system.h
@@ -9,6 +9,7 @@
#include <bitcoin-build-config.h> // IWYU pragma: keep
#include <cstdint>
+#include <optional>
#include <string>
// Application startup time (used for uptime calculation)
@@ -29,4 +30,9 @@ void runCommand(const std::string& strCommand);
*/
int GetNumCores();
+/**
+ * Return the total RAM available on the current system, if detectable.
+ */
+std::optional<size_t> GetTotalRAM();
+
#endif // BITCOIN_COMMON_SYSTEM_H
diff --git a/src/test/system_tests.cpp b/src/test/system_tests.cpp
index dec4d418..53db3200 100644
--- a/src/test/system_tests.cpp
+++ b/src/test/system_tests.cpp
@@ -8,6 +8,8 @@
#include <common/run_command.h>
#include <univalue.h>
+#include <common/system.h>
+
#ifdef ENABLE_EXTERNAL_SIGNER
#include <util/subprocess.h>
#endif // ENABLE_EXTERNAL_SIGNER
@@ -16,6 +18,17 @@
BOOST_FIXTURE_TEST_SUITE(system_tests, BasicTestingSetup)
+BOOST_AUTO_TEST_CASE(total_ram)
+{
+ BOOST_CHECK_GE(GetTotalRAM(), 1000_MiB);
+
+ if constexpr (SIZE_MAX == UINT64_MAX) {
+ // Upper bound check only on 64-bit: 32-bit systems can reasonably have max memory,
+ // but extremely large values on 64-bit likely indicate detection errors
+ BOOST_CHECK_LT(GetTotalRAM(), 10'000'000_MiB); // >10 TiB memory is unlikely
+ }
+}
+
#ifdef ENABLE_EXTERNAL_SIGNER
BOOST_AUTO_TEST_CASE(run_command)
Why this scored 15/100
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