More robust process functions.

src/process.cpp

@@ -7,14 +7,17 @@ Process::Process(const std::string &command, const std::string &path,
                  std::function<void(const char* bytes, size_t n)> read_stdout,
                  std::function<void(const char* bytes, size_t n)> read_stderr,
                  bool open_stdin, size_t buffer_size):
-                 read_stdout(read_stdout), read_stderr(read_stderr), open_stdin(open_stdin), buffer_size(buffer_size) {
-  id=open(command, path);
-  if(id>0)
+                 closed(true), read_stdout(read_stdout), read_stderr(read_stderr), open_stdin(open_stdin), buffer_size(buffer_size) {
+  open(command, path);
   async_read();
 }
 
 Process::~Process() {
-  close_all();
+  close_fds();
+}
+
+Process::id_type Process::get_id() {
+  return data.id;
 }
 
 bool Process::write(const std::string &data) {

src/process.hpp

@@ -6,6 +6,7 @@
 #include <vector>
 #include <mutex>
 #include <thread>
+#include <mutex>
 #ifdef _WIN32
 #include <windows.h>
 #else
@@ -26,6 +27,16 @@ public:
   typedef pid_t id_type;
   typedef int fd_type;
 #endif
+private:
+  class Data {
+  public:
+    Data();
+    id_type id;
+#ifdef _WIN32
+    HANDLE handle;
+#endif
+  };
+public:
   Process(const std::string &command, const std::string &path=std::string(),
           std::function<void(const char *bytes, size_t n)> read_stdout=nullptr,
           std::function<void(const char *bytes, size_t n)> read_stderr=nullptr,
@@ -34,7 +45,7 @@ public:
   ~Process();
   
   ///Get the process id of the started process.
-  id_type get_id() {return id;}
+  id_type get_id();
   ///Wait until process is finished, and return exit status.
   int get_exit_status();
   ///Write to stdin.
@@ -44,10 +55,15 @@ public:
   ///Close stdin. If the process takes parameters from stdin, use this to notify that all parameters have been sent.
   void close_stdin();
   
+  ///Kill the process.
+  void kill(bool force=false);
   ///Kill a given process id.
   static void kill(id_type id, bool force=false);
   
 private:
+  Data data;
+  bool closed;
+  std::mutex close_mutex;
   std::function<void(const char* bytes, size_t n)> read_stdout;
   std::function<void(const char* bytes, size_t n)> read_stderr;
   std::thread stdout_thread, stderr_thread;
@@ -58,9 +74,8 @@ private:
   std::unique_ptr<fd_type> stdout_fd, stderr_fd, stdin_fd;
   
   id_type open(const std::string &command, const std::string &path);
-  id_type id;
   void async_read();
-  void close_all();
+  void close_fds();
 };
 
 #endif  // TINY_PROCESS_LIBRARY_HPP_

src/process_unix.cpp

@@ -6,6 +6,8 @@
 #include <iostream> //TODO: remove
 using namespace std; //TODO: remove
 
+Process::Data::Data(): id(-1) {}
+
 Process::id_type Process::open(const std::string &command, const std::string &path) {
   if(open_stdin)
     stdin_fd=std::unique_ptr<fd_type>(new fd_type);
@@ -78,10 +80,14 @@ Process::id_type Process::open(const std::string &command, const std::string &pa
   if(stdout_fd) *stdout_fd = stdout_p[0];
   if(stderr_fd) *stderr_fd = stderr_p[0];
 
+  closed=false;
+  data.id=pid;
   return pid;
 }
 
 void Process::async_read() {
+  if(data.id<=0)
+    return;
   if(stdout_fd) {
     stdout_thread=std::thread([this](){
       char buffer[buffer_size];
@@ -101,17 +107,20 @@ void Process::async_read() {
 }
 
 int Process::get_exit_status() {
-  if(id<=0)
+  if(data.id<=0)
     return -1;
   int exit_status;
-  waitpid(id, &exit_status, 0);
+  waitpid(data.id, &exit_status, 0);
+  close_mutex.lock();
+  closed=true;
+  close_mutex.unlock();
   
-  close_all();
+  close_fds();
   
   return exit_status;
 }
 
-void Process::close_all() {
+void Process::close_fds() {
   if(stdout_thread.joinable())
     stdout_thread.join();
   if(stderr_thread.joinable())
@@ -154,6 +163,17 @@ void Process::close_stdin() {
   stdin_mutex.unlock();
 }
 
+void Process::kill(bool force) {
+  close_mutex.lock();
+  if(data.id>0 && !closed) {
+    if(force)
+      ::kill(-data.id, SIGTERM);
+    else
+      ::kill(-data.id, SIGINT);
+  }
+  close_mutex.unlock();
+}
+
 void Process::kill(id_type id, bool force) {
   if(id<=0)
     return;

src/process_win.cpp

@@ -5,6 +5,8 @@
 #include <iostream> //TODO: remove
 using namespace std; //TODO: remove
 
+Process::Data::Data(): id(0), handle(NULL) {}
+
 //Based on the example at https://msdn.microsoft.com/en-us/library/windows/desktop/ms682499(v=vs.85).aspx.
 //Note: on Windows it seems impossible to specify which pipes to use.
 //Thus, if read_stdout==nullptr, read_stderr==nullptr and open_stdin==false, the stdout, stderr and stdin are sent to the parent process instead.
@@ -138,10 +140,15 @@ Process::id_type Process::open(const std::string &command, const std::string &pa
   if(stdout_fd) *stdout_fd=g_hChildStd_OUT_Rd;
   if(stderr_fd) *stderr_fd=g_hChildStd_ERR_Rd;
   
+  closed=false;
+  data.id=process_info.dwProcessId;
+  data.handle=process_info.hProcess;
   return process_info.dwProcessId;
 }
 
 void Process::async_read() {
+  if(data.id==0)
+    return;
   if(stdout_fd) {
     stdout_thread=std::thread([this](){
       DWORD n;
@@ -169,24 +176,23 @@ void Process::async_read() {
 }
 
 int Process::get_exit_status() {
-  if(id==0)
+  if(data.id==0)
     return -1;
   DWORD exit_status;
-  HANDLE process_handle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, id);
-  if(process_handle) {
-    WaitForSingleObject(process_handle, INFINITE);
-    GetExitCodeProcess(process_handle, &exit_status);
-    CloseHandle(process_handle);
-  }
-  else
+  WaitForSingleObject(data.handle, INFINITE);
+  if(!GetExitCodeProcess(data.handle, &exit_status))
     exit_status=-1;
+  close_mutex.lock();
+  CloseHandle(data.handle);
+  closed=true;
+  close_mutex.unlock();
   
-  close_all();
+  close_fds();
   
   return static_cast<int>(exit_status);
 }
 
-void Process::close_all() {
+void Process::close_fds() {
   if(stdout_thread.joinable())
     stdout_thread.join();
   if(stderr_thread.joinable())
@@ -231,6 +237,29 @@ void Process::close_stdin() {
   stdin_mutex.unlock();
 }
 
+//Based on http://stackoverflow.com/a/1173396
+void Process::kill(bool force) {
+  close_mutex.lock();
+  if(data.id>0 && !closed) {
+    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+    if(snapshot) {
+      PROCESSENTRY32 process;
+      ZeroMemory(&process, sizeof(process));
+      process.dwSize = sizeof(process);
+      if(Process32First(snapshot, &process)) {
+        do {
+          if(process.th32ParentProcessID==data.id) {
+            HANDLE process_handle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, process.th32ProcessID);
+            if(process_handle) TerminateProcess(process_handle, 2);
+          }
+        } while (Process32Next(snapshot, &process));
+      }
+    }
+    TerminateProcess(data.handle, 2);
+  }
+  close_mutex.unlock();
+}
+
 //Based on http://stackoverflow.com/a/1173396
 void Process::kill(id_type id, bool force) {
   if(id==0)

src/terminal.cc

@@ -166,14 +166,14 @@ void Terminal::async_process(const std::string &command, const boost::filesystem
 void Terminal::kill_last_async_process(bool force) {
   processes_mutex.lock();
   if(processes.size()>0)
-    Process::kill(processes.back()->get_id(), force);
+    processes.back()->kill(force);
   processes_mutex.unlock();
 }
 
 void Terminal::kill_async_processes(bool force) {
   processes_mutex.lock();
   for(auto &process: processes)
-    Process::kill(process->get_id(), force);
+    process->kill(force);
   processes_mutex.unlock();
 }