Add `zen ui` command (#779)

Allows user to automate launching of zenserver dashboard, including when multiple instances are running. If multiple instances are running you can open all dashboards with `--all`, and also using the in-terminal chooser which also allows you to open a specific instance.

Also includes a fix to `zen exec` when using offset/stride/limit

1 files changed, 226 insertions, 0 deletions

diff --git a/src/zencore/process.cpp b/src/zencore/process.cpp
index 56849a10d..4a2668912 100644
--- a/src/zencore/process.cpp
+++ b/src/zencore/process.cpp
@@ -1001,6 +1001,232 @@ GetProcessExecutablePath(int Pid, std::error_code& OutEc)
 #endif	// ZEN_PLATFORM_LINUX
 }
 
+std::string
+GetProcessCommandLine(int Pid, std::error_code& OutEc)
+{
+#if ZEN_PLATFORM_WINDOWS
+	HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, static_cast<DWORD>(Pid));
+	if (!hProcess)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+	auto _ = MakeGuard([hProcess] { CloseHandle(hProcess); });
+
+	// NtQueryInformationProcess is an undocumented NT API; load it dynamically.
+	// Info class 60 = ProcessCommandLine, available since Windows 8.1.
+	using PFN_NtQIP = LONG(WINAPI*)(HANDLE, UINT, PVOID, ULONG, PULONG);
+	static const PFN_NtQIP s_NtQIP =
+		reinterpret_cast<PFN_NtQIP>(GetProcAddress(GetModuleHandleW(L"ntdll.dll"), "NtQueryInformationProcess"));
+	if (!s_NtQIP)
+	{
+		return {};
+	}
+
+	constexpr UINT ProcessCommandLineClass	= 60;
+	constexpr LONG StatusInfoLengthMismatch = static_cast<LONG>(0xC0000004L);
+
+	ULONG ReturnLength = 0;
+	LONG  Status	   = s_NtQIP(hProcess, ProcessCommandLineClass, nullptr, 0, &ReturnLength);
+	if (Status != StatusInfoLengthMismatch || ReturnLength == 0)
+	{
+		return {};
+	}
+
+	std::vector<char> Buf(ReturnLength);
+	Status = s_NtQIP(hProcess, ProcessCommandLineClass, Buf.data(), ReturnLength, &ReturnLength);
+	if (Status < 0)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+
+	// Output: UNICODE_STRING header immediately followed by the UTF-16 string data.
+	// The UNICODE_STRING.Buffer field points into our Buf.
+	struct LocalUnicodeString
+	{
+		USHORT Length;
+		USHORT MaximumLength;
+		WCHAR* Buffer;
+	};
+	if (ReturnLength < sizeof(LocalUnicodeString))
+	{
+		return {};
+	}
+	const auto* Us = reinterpret_cast<const LocalUnicodeString*>(Buf.data());
+	if (Us->Length == 0 || Us->Buffer == nullptr)
+	{
+		return {};
+	}
+
+	// Skip argv[0]: may be a quoted path ("C:\...\exe.exe") or a bare path
+	const WCHAR* p	 = Us->Buffer;
+	const WCHAR* End = Us->Buffer + Us->Length / sizeof(WCHAR);
+	if (p < End && *p == L'"')
+	{
+		++p;
+		while (p < End && *p != L'"')
+		{
+			++p;
+		}
+		if (p < End)
+		{
+			++p;  // skip closing quote
+		}
+	}
+	else
+	{
+		while (p < End && *p != L' ')
+		{
+			++p;
+		}
+	}
+	while (p < End && *p == L' ')
+	{
+		++p;
+	}
+	if (p >= End)
+	{
+		return {};
+	}
+
+	int Utf8Size = WideCharToMultiByte(CP_UTF8, 0, p, static_cast<int>(End - p), nullptr, 0, nullptr, nullptr);
+	if (Utf8Size <= 0)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+	std::string Result(Utf8Size, '\0');
+	WideCharToMultiByte(CP_UTF8, 0, p, static_cast<int>(End - p), Result.data(), Utf8Size, nullptr, nullptr);
+	return Result;
+
+#elif ZEN_PLATFORM_LINUX
+	std::string CmdlinePath = fmt::format("/proc/{}/cmdline", Pid);
+	FILE*		F			= fopen(CmdlinePath.c_str(), "rb");
+	if (!F)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+	auto FGuard = MakeGuard([F] { fclose(F); });
+
+	// /proc/{pid}/cmdline contains null-separated argv entries; read it all
+	std::string Raw;
+	char		Chunk[4096];
+	size_t		BytesRead;
+	while ((BytesRead = fread(Chunk, 1, sizeof(Chunk), F)) > 0)
+	{
+		Raw.append(Chunk, BytesRead);
+	}
+	if (Raw.empty())
+	{
+		return {};
+	}
+
+	// Skip argv[0] (first null-terminated entry)
+	const char* p	= Raw.data();
+	const char* End = Raw.data() + Raw.size();
+	while (p < End && *p != '\0')
+	{
+		++p;
+	}
+	if (p < End)
+	{
+		++p;  // skip null terminator of argv[0]
+	}
+
+	// Build result: remaining entries joined by spaces (inter-arg nulls → spaces)
+	std::string Result;
+	Result.reserve(static_cast<size_t>(End - p));
+	for (const char* q = p; q < End; ++q)
+	{
+		Result += (*q == '\0') ? ' ' : *q;
+	}
+	while (!Result.empty() && Result.back() == ' ')
+	{
+		Result.pop_back();
+	}
+	return Result;
+
+#elif ZEN_PLATFORM_MAC
+	int	   Mib[3]  = {CTL_KERN, KERN_PROCARGS2, Pid};
+	size_t BufSize = 0;
+	if (sysctl(Mib, 3, nullptr, &BufSize, nullptr, 0) != 0 || BufSize == 0)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+
+	std::vector<char> Buf(BufSize);
+	if (sysctl(Mib, 3, Buf.data(), &BufSize, nullptr, 0) != 0)
+	{
+		OutEc = MakeErrorCodeFromLastError();
+		return {};
+	}
+
+	// Layout: [int argc][exec_path\0][null padding][argv[0]\0][argv[1]\0]...[envp\0]...
+	if (BufSize < sizeof(int))
+	{
+		return {};
+	}
+	int Argc = 0;
+	memcpy(&Argc, Buf.data(), sizeof(int));
+	if (Argc <= 1)
+	{
+		return {};
+	}
+
+	const char* p	= Buf.data() + sizeof(int);
+	const char* End = Buf.data() + BufSize;
+
+	// Skip exec_path and any trailing null padding that follows it
+	while (p < End && *p != '\0')
+	{
+		++p;
+	}
+	while (p < End && *p == '\0')
+	{
+		++p;
+	}
+
+	// Skip argv[0]
+	while (p < End && *p != '\0')
+	{
+		++p;
+	}
+	if (p < End)
+	{
+		++p;
+	}
+
+	// Collect argv[1..Argc-1]
+	std::string Result;
+	for (int i = 1; i < Argc && p < End; ++i)
+	{
+		if (i > 1)
+		{
+			Result += ' ';
+		}
+		const char* ArgStart = p;
+		while (p < End && *p != '\0')
+		{
+			++p;
+		}
+		Result.append(ArgStart, p);
+		if (p < End)
+		{
+			++p;
+		}
+	}
+	return Result;
+
+#else
+	ZEN_UNUSED(Pid);
+	ZEN_UNUSED(OutEc);
+	return {};
+#endif
+}
+
 std::error_code
 FindProcess(const std::filesystem::path& ExecutableImage, ProcessHandle& OutHandle, bool IncludeSelf)
 {