common: add subproc.h wrapper, disabled on android/ios

CMakeLists.txt

@@ -84,6 +84,14 @@ else()
     set(LLAMA_TOOLS_INSTALL_DEFAULT ${LLAMA_STANDALONE})
 endif()
 
+# subprocess spawning isn't a supported/sandbox-friendly operation on mobile OSes or in WASM
+if (CMAKE_SYSTEM_NAME STREQUAL "iOS" OR CMAKE_SYSTEM_NAME STREQUAL "Android" OR ANDROID
+        OR CMAKE_SYSTEM_NAME STREQUAL "Emscripten" OR EMSCRIPTEN)
+    set(LLAMA_SUBPROCESS_DEFAULT OFF)
+else()
+    set(LLAMA_SUBPROCESS_DEFAULT ON)
+endif()
+
 #
 # option list
 #
@@ -117,6 +125,7 @@ option(LLAMA_TESTS_INSTALL "llama: install tests" ON)
 
 # 3rd party libs
 option(LLAMA_OPENSSL    "llama: use openssl to support HTTPS" ON)
+option(LLAMA_SUBPROCESS "llama-common: use subprocess, required by server tools and server router mode" ${LLAMA_SUBPROCESS_DEFAULT})
 option(LLAMA_LLGUIDANCE "llama-common: include LLGuidance library for structured output in common utils" OFF)
 
 

common/CMakeLists.txt

@@ -100,6 +100,8 @@ add_library(${TARGET}
     sampling.h
     speculative.cpp
     speculative.h
+    subproc.cpp
+    subproc.h
     trie.cpp
     trie.h
     unicode.cpp
@@ -127,6 +129,10 @@ set_target_properties(${TARGET} PROPERTIES
 target_include_directories(${TARGET} PUBLIC . ../vendor)
 target_compile_features   (${TARGET} PUBLIC cxx_std_17)
 
+if (LLAMA_SUBPROCESS)
+    target_compile_definitions(${TARGET} PUBLIC LLAMA_SUBPROCESS)
+endif()
+
 if (BUILD_SHARED_LIBS)
     set_target_properties(${TARGET} PROPERTIES POSITION_INDEPENDENT_CODE ON)
 

common/subproc.cpp

@@ -0,0 +1,143 @@
+#include "subproc.h"
+
+bool common_subproc::is_supported() {
+#ifdef LLAMA_SUBPROCESS
+    return true;
+#else
+    return false;
+#endif
+}
+
+#ifdef LLAMA_SUBPROCESS
+
+static std::vector<char *> to_cstr_vec(const std::vector<std::string> & v) {
+    std::vector<char *> r;
+    r.reserve(v.size() + 1);
+    for (const auto & s : v) {
+        r.push_back(const_cast<char *>(s.c_str()));
+    }
+    r.push_back(nullptr);
+    return r;
+}
+
+common_subproc::~common_subproc() {
+    if (is_created) {
+        subprocess_destroy(&proc);
+        is_created = false;
+    }
+}
+
+bool common_subproc::create(
+        const std::vector<std::string> & args,
+        int options,
+        const std::vector<std::string> & env,
+        const char * cwd) {
+    auto argv = to_cstr_vec(args);
+
+    int result;
+    if (env.empty() && cwd == nullptr) {
+        result = subprocess_create(argv.data(), options, &proc);
+    } else {
+        auto envp = to_cstr_vec(env);
+        result = subprocess_create_ex(argv.data(), options, env.empty() ? nullptr : envp.data(), cwd, &proc);
+    }
+
+    is_created = result == 0;
+    return is_created;
+}
+
+bool common_subproc::has_handle() const {
+    if (!is_created) {
+        return false;
+    }
+#if defined(_WIN32)
+    return proc.hProcess != nullptr;
+#else
+    return proc.child > 0;
+#endif
+}
+
+bool common_subproc::alive() {
+    return is_created && subprocess_alive(&proc);
+}
+
+FILE * common_subproc::stdin_file() {
+    return is_created ? subprocess_stdin(&proc) : nullptr;
+}
+
+FILE * common_subproc::stdout_file() {
+    return is_created ? subprocess_stdout(&proc) : nullptr;
+}
+
+FILE * common_subproc::stderr_file() {
+    return is_created ? subprocess_stderr(&proc) : nullptr;
+}
+
+void common_subproc::close_stdin() {
+    if (is_created && proc.stdin_file) {
+        fclose(proc.stdin_file);
+        proc.stdin_file = nullptr;
+    }
+}
+
+void common_subproc::terminate() {
+    if (has_handle()) {
+        subprocess_terminate(&proc);
+    }
+}
+
+int common_subproc::join() {
+    int exit_code = -1;
+    if (is_created) {
+        subprocess_join(&proc, &exit_code);
+        subprocess_destroy(&proc);
+        is_created = false;
+    }
+    return exit_code;
+}
+
+#else // !LLAMA_SUBPROCESS
+
+common_subproc::~common_subproc() = default;
+
+bool common_subproc::create(
+        const std::vector<std::string> &,
+        int,
+        const std::vector<std::string> &,
+        const char *) {
+    (void)(proc);
+    (void)(is_created);
+    return false;
+}
+
+bool common_subproc::has_handle() const {
+    return false;
+}
+
+bool common_subproc::alive() {
+    return false;
+}
+
+FILE * common_subproc::stdin_file() {
+    return nullptr;
+}
+
+FILE * common_subproc::stdout_file() {
+    return nullptr;
+}
+
+FILE * common_subproc::stderr_file() {
+    return nullptr;
+}
+
+void common_subproc::close_stdin() {
+}
+
+void common_subproc::terminate() {
+}
+
+int common_subproc::join() {
+    return -1;
+}
+
+#endif // LLAMA_SUBPROCESS

common/subproc.h

@@ -0,0 +1,59 @@
+#pragma once
+
+#include <atomic>
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#ifdef LLAMA_SUBPROCESS
+#include <sheredom/subprocess.h>
+#else
+// dummy values to allow compilation when subprocess is disabled
+struct subprocess_s {};
+static constexpr int subprocess_option_no_window = 0;
+static constexpr int subprocess_option_combined_stdout_stderr = 0;
+static constexpr int subprocess_option_inherit_environment = 0;
+static constexpr int subprocess_option_search_user_path = 0;
+#endif
+
+// RAII-style wrapper around https://github.com/sheredom/subprocess.h,
+// exposing method calls instead of free functions operating on subprocess_s.
+struct common_subproc {
+    common_subproc() = default;
+    ~common_subproc();
+
+    common_subproc(const common_subproc &) = delete;
+    common_subproc & operator=(const common_subproc &) = delete;
+
+    // spawn a child process; if env is non-empty it replaces the child's environment
+    // (do not combine with subprocess_option_inherit_environment)
+    bool create(
+            const std::vector<std::string> & args,
+            int options,
+            const std::vector<std::string> & env = {},
+            const char * cwd = nullptr);
+
+    bool alive();
+
+    // true if LLAMA_SUBPROCESS was enabled at build time; when false, create() always fails
+    static bool is_supported();
+
+    FILE * stdin_file();
+    FILE * stdout_file();
+    FILE * stderr_file();
+
+    // close stdin and detach it from the process, so a later join()/destroy() won't double-close it;
+    // use this after writing all input to signal EOF to the child while it's still running
+    void close_stdin();
+
+    void terminate();
+
+    // wait for the process to exit, release the underlying handle and return its exit code
+    int join();
+
+private:
+    subprocess_s proc {};
+    std::atomic<bool> is_created{false};
+
+    bool has_handle() const;
+};

tests/test-jinja.cpp

@@ -4,7 +4,7 @@
 #include <cstdlib>
 
 #include <nlohmann/json.hpp>
-#include <sheredom/subprocess.h>
+#include "subproc.h"
 
 #include "jinja/runtime.h"
 #include "jinja/parser.h"
@@ -2135,46 +2135,43 @@ static void test_template_py(testing & t, const std::string & name, const std::s
         const char * python_executable = "python3";
 #endif
 
-        const char * command_line[] = {python_executable, "-c", py_script.c_str(), NULL};
+        std::vector<std::string> args = {python_executable, "-c", py_script, };
 
-        struct subprocess_s subprocess;
+        common_subproc subprocess;
         int options = subprocess_option_combined_stdout_stderr
                     | subprocess_option_no_window
                     | subprocess_option_inherit_environment
                     | subprocess_option_search_user_path;
-        int result = subprocess_create(command_line, options, &subprocess);
 
-        if (result != 0) {
-            t.log("Failed to create subprocess, error code: " + std::to_string(result));
+        if (!subprocess.create(args, options)) {
+            t.log("Failed to create subprocess");
             t.assert_true("subprocess creation", false);
             return;
         }
-        FILE * p_stdin = subprocess_stdin(&subprocess);
+        FILE * p_stdin = subprocess.stdin_file();
 
         // Write input
         std::string input = merged.dump();
         auto written = fwrite(input.c_str(), 1, input.size(), p_stdin);
         if (written != input.size()) {
             t.log("Failed to write complete input to subprocess stdin");
             t.assert_true("subprocess stdin write", false);
-            subprocess_destroy(&subprocess);
+            subprocess.close_stdin();
+            subprocess.join();
             return;
         }
         fflush(p_stdin);
-        fclose(p_stdin); // Close stdin to signal EOF to the Python process
-        subprocess.stdin_file = nullptr;
+        subprocess.close_stdin(); // Close stdin to signal EOF to the Python process
 
         // Read output
         std::string output;
         char buffer[1024];
-        FILE * p_stdout = subprocess_stdout(&subprocess);
+        FILE * p_stdout = subprocess.stdout_file();
         while (fgets(buffer, sizeof(buffer), p_stdout)) {
             output += buffer;
         }
 
-        int process_return;
-        subprocess_join(&subprocess, &process_return);
-        subprocess_destroy(&subprocess);
+        int process_return = subprocess.join();
 
         if (process_return != 0) {
             t.log("Python script failed with exit code: " + std::to_string(process_return));

tools/mtmd/CMakeLists.txt

@@ -1,8 +1,15 @@
 # mtmd
 
-set(MTMD_VIDEO ON CACHE BOOL "enable video support in mtmd (requires ffmpeg binary in PATH)")
+set(MTMD_VIDEO_HELP "enable video support in mtmd (requires ffmpeg binary in PATH)")
+
+set(MTMD_VIDEO ON CACHE BOOL "${MTMD_VIDEO_HELP}")
 # TODO: add MTMD_VIDEO_METHOD in the future to select between ffmpeg and other backends
 
+if (MTMD_VIDEO AND NOT LLAMA_SUBPROCESS)
+    message(STATUS "Disabling MTMD_VIDEO because LLAMA_SUBPROCESS is OFF")
+    set(MTMD_VIDEO OFF CACHE BOOL "${MTMD_VIDEO_HELP}" FORCE)
+endif()
+
 find_package(Threads REQUIRED)
 
 add_library(mtmd

tools/server/server-mcp.cpp

@@ -1,6 +1,6 @@
 #include "server-mcp.h"
 
-#include <sheredom/subprocess.h>
+#include "subproc.h"
 
 #include <atomic>
 #include <chrono>
@@ -341,7 +341,7 @@ json server_mcp_transport::call_tool(const std::string & tool_name,
 //
 
 struct server_mcp_stdio::process_handle {
-    subprocess_s sp;
+    common_subproc sp;
     FILE * in  = nullptr; // child stdin
     FILE * out = nullptr; // child stdout
     FILE * err = nullptr; // child stderr
@@ -483,30 +483,15 @@ bool server_mcp_stdio::start() {
         envp_s = mcp_build_env(config.env);
     }
 
-    auto to_ptrs = [](std::vector<std::string> & v) {
-        std::vector<const char *> p;
-        p.reserve(v.size() + 1);
-        for (auto & s : v) {
-            p.push_back(s.c_str());
-        }
-        p.push_back(nullptr);
-        return p;
-    };
-    auto argv = to_ptrs(argv_s);
-    auto envp = to_ptrs(envp_s);
-
     auto handle = std::make_unique<process_handle>();
-    int rc = subprocess_create_ex(argv.data(), options,
-                                  config.env.empty() ? nullptr : envp.data(),
-                                  config.cwd.empty() ? nullptr : config.cwd.c_str(),
-                                  &handle->sp);
-    if (rc != 0) {
+    bool ok = handle->sp.create(argv_s, options, envp_s, config.cwd.empty() ? nullptr : config.cwd.c_str());
+    if (!ok) {
         SRV_WRN("MCP '%s': failed to spawn '%s'\n", config.name.c_str(), config.command.c_str());
         return false;
     }
-    handle->in  = subprocess_stdin(&handle->sp);
-    handle->out = subprocess_stdout(&handle->sp);
-    handle->err = subprocess_stderr(&handle->sp);
+    handle->in  = handle->sp.stdin_file();
+    handle->out = handle->sp.stdout_file();
+    handle->err = handle->sp.stderr_file();
 
     proc = std::move(handle);
     running.store(true);
@@ -654,14 +639,13 @@ void server_mcp_stdio::join_pumps() {
     to_server.close_write();   // wake the writer if it waits for a message
     from_server.close_write(); // wake any caller waiting for a reply
 
-    subprocess_terminate(&proc->sp); // child death unblocks the blocked fread/fwrite
+    proc->sp.terminate(); // child death unblocks the blocked fread/fwrite
 
     if (writer.joinable()) writer.join();
     if (reader.joinable()) reader.join();
     if (errlog.joinable()) errlog.join();
 
-    subprocess_join(&proc->sp, nullptr); // reap the child: destroy() never waits, so the pid would stay a zombie for the process lifetime
-    subprocess_destroy(&proc->sp); // safe now: no thread touches the FILE* anymore
+    proc->sp.join(); // reap the child: never waiting would leave the pid a zombie for the process lifetime
     proc.reset();
 }