From bf9f0d6338e5043a1816ff9995261c6fd032a8fe Mon Sep 17 00:00:00 2001
From: ValKmjolnir <lhk101lhk101@qq.com>
Date: Wed, 12 Jun 2024 01:25:40 +0800
Subject: [PATCH] :sparkles: add subprocess.fork/kill

---
 src/nasal_codegen.h        |   4 +-
 src/nasal_import.cpp       |   9 ++-
 src/natives/subprocess.cpp | 112 +++++++++++++++++++++++++++++++++++++
 src/natives/subprocess.h   |   3 +
 std/dylib.nas              |   2 +-
 std/subprocess.nas         |  10 +++-
 6 files changed, 136 insertions(+), 4 deletions(-)

diff --git a/src/nasal_codegen.h b/src/nasal_codegen.h
index ab742c9..175fb06 100644
--- a/src/nasal_codegen.h
+++ b/src/nasal_codegen.h
@@ -62,7 +62,9 @@ private:
         // subprocess
         "__subprocess_popen",
         "__subprocess_pclose",
-        "__subprocess_read_stdout"
+        "__subprocess_read_stdout",
+        "__subprocess_fork",
+        "__subprocess_kill"
     };
 
     // file mapper for file -> index
diff --git a/src/nasal_import.cpp b/src/nasal_import.cpp
index 4093516..77a206e 100644
--- a/src/nasal_import.cpp
+++ b/src/nasal_import.cpp
@@ -9,8 +9,15 @@
 namespace nasal {
 
 linker::linker(): show_path_flag(false), this_file("") {
+    const auto env_get_path = getenv("PATH");
+    if (!env_get_path) {
+        err.warn("link", "cannot get env \"PATH\".");
+        envpath = {};
+        return;
+    }
+
     const auto seperator = util::is_windows()? ';':':';
-    const auto PATH = std::string(getenv("PATH"));
+    const auto PATH = std::string(env_get_path);
     usize last = 0, position = PATH.find(seperator, 0);
     while(position!=std::string::npos) {
         std::string dirpath = PATH.substr(last, position-last);
diff --git a/src/natives/subprocess.cpp b/src/natives/subprocess.cpp
index f6974e0..91a63a5 100644
--- a/src/natives/subprocess.cpp
+++ b/src/natives/subprocess.cpp
@@ -4,9 +4,17 @@
 #ifdef _MSC_VER
 #define popen _popen
 #define pclose _pclose
+#define perror _perror
+#endif
+
+#ifndef _MSC_VER
+#include <unistd.h>
+#include <sys/wait.h>
 #endif
 
 #include <cstdio>
+#include <cstdlib>
+#include <vector>
 
 namespace nasal {
 
@@ -59,10 +67,114 @@ var builtin_subprocess_read_stdout(context* ctx, gc* ngc) {
     return res;
 }
 
+var builtin_subprocess_fork(context* ctx, gc* ngc) {
+    auto cmd = ctx->localr[1];
+    if (!cmd.is_vec()) {
+        return nas_err("subprocess::fork", "expect a string as the command");
+    }
+
+#ifdef WIN32
+    // STARTUPINFO si;
+    // PROCESS_INFORMATION pi;
+
+    // // init STARTUPINFO
+    // ZeroMemory(&si, sizeof(si));
+    // si.cb = sizeof(si);
+    // si.dwFlags = STARTF_USESHOWWINDOW;
+    // si.wShowWindow = SW_SHOW;
+
+    // // init PROCESS_INFORMATION
+    // ZeroMemory(&pi, sizeof(pi));
+
+    // auto len = MultiByteToWideChar(CP_UTF8, 0, cmd.str().c_str(), -1, nullptr, 0);
+
+    // auto res = CreateProcess(
+    //     nullptr,
+    //     cmd.str().c_str(),
+    //     nullptr,
+    //     nullptr,
+    //     false,
+    //     0,
+    //     nullptr,
+    //     nullptr,
+    //     &si,
+    //     &pi
+    // );
+#else
+    // create argv
+    char** argv = new char*[cmd.vec().elems.size()+1];
+    for(const auto& v : cmd.vec().elems) {
+        if (!v.is_str()) {
+            return nas_err("subprocess::fork", "non-string arguments");
+        }
+    }
+    for(usize i = 0; i<cmd.vec().elems.size(); ++i) {
+        argv[i] = strdup(cmd.vec().elems[i].str().c_str());
+    }
+    argv[cmd.vec().elems.size()] = nullptr;
+
+    // use the same env of parent process
+    char** env = nullptr;
+    if (getenv("PATH")) {
+        env = new char*[2];
+        env[0] = strdup((std::string("PATH=") + getenv("PATH")).c_str());
+        env[1] = nullptr;
+    } else {
+        env = new char*[1];
+        env[0] = nullptr;
+    }
+
+    // create child process
+    auto pid = fork();
+    if (pid < 0) {
+        return nas_err("subprocess::fork", "failed to create sub-process");
+    }
+    // child process
+    if (pid==0) {
+        execve("nasal", argv, env);
+        _exit(-1);
+    }
+
+    // parent process
+    for(usize i = 0; argv[i]; ++i) {
+        delete argv[i];
+    }
+    delete[] argv;
+    for(usize i = 0; env[i]; ++i) {
+        delete env[i];
+    }
+    delete[] env;
+    return var::num(pid);
+#endif
+
+    return nil;
+}
+
+var builtin_subprocess_kill(context* ctx, gc* ngc) {
+#ifdef WIN32
+    // TODO
+#else
+    auto pid = ctx->localr[1];
+    if (!pid.is_num()) {
+        return nas_err("subprocess::kill", "need numeral pid");
+    }
+
+    int status;
+    pid_t result = waitpid(pid.num(), &status, WNOHANG);
+    // child process running
+    if (result==0) {
+        kill(pid.num(), SIGTERM);
+    }
+#endif
+    return nil;
+}
+
 nasal_builtin_table subprocess_native[] = {
     {"__subprocess_popen", builtin_subprocess_popen},
     {"__subprocess_pclose", builtin_subprocess_pclose},
     {"__subprocess_read_stdout", builtin_subprocess_read_stdout},
+    {"__subprocess_fork", builtin_subprocess_fork},
+    {"__subprocess_kill", builtin_subprocess_kill},
     {nullptr, nullptr}
 };
 
diff --git a/src/natives/subprocess.h b/src/natives/subprocess.h
index 23029a4..144b63d 100644
--- a/src/natives/subprocess.h
+++ b/src/natives/subprocess.h
@@ -11,6 +11,9 @@ void subprocess_destructor(void*);
 var builtin_subprocess_popen(context*, gc*);
 var builtin_subprocess_pclose(context*, gc*);
 var builtin_subprocess_read_stdout(context*, gc*);
+
+var builtin_subprocess_fork(context*, gc*);
+var builtin_subprocess_kill(context*, gc*);
 extern nasal_builtin_table subprocess_native[];
 
 }
\ No newline at end of file
diff --git a/std/dylib.nas b/std/dylib.nas
index a808653..a63b0a0 100644
--- a/std/dylib.nas
+++ b/std/dylib.nas
@@ -13,7 +13,7 @@ var dlopen = func(libname) {
     if (io.exists(libname))
         return __dlopen(libname);
     # find dynamic lib through PATH
-    var envpath = split(os.platform()=="windows"? ";":":",unix.getenv("PATH"));
+    var envpath = split(os.platform()=="windows"? ";":":", unix.getenv("PATH"));
     # first find ./module
     append(envpath, ".");
     var path = os.platform()=="windows"? "\\module\\":"/module/";
diff --git a/std/subprocess.nas b/std/subprocess.nas
index e82cf8b..c8b5abf 100644
--- a/std/subprocess.nas
+++ b/std/subprocess.nas
@@ -8,4 +8,12 @@ var pclose = func(subproc) {
 
 var read = func(subproc) {
     return __subprocess_read_stdout(subproc);
-}
\ No newline at end of file
+}
+
+var fork = func(vec) {
+    return __subprocess_fork(vec);
+}
+
+var kill = func(pid) {
+    return __subprocess_kill(pid);
+}