common: Windows 'spawn' support for tx and block notifications

src/common/CMakeLists.txt

@@ -34,13 +34,13 @@ set(common_sources
   dns_utils.cpp
   download.cpp
   error.cpp
-  exec.cpp
   expect.cpp
   util.cpp
   i18n.cpp
   notify.cpp
   password.cpp
   perf_timer.cpp
+  spawn.cpp
   threadpool.cpp
   updates.cpp
   aligned.c)
@@ -60,7 +60,6 @@ set(common_private_headers
   dns_utils.h
   download.h
   error.h
-  exec.h
   expect.h
   http_connection.h
   int-util.h
@@ -74,6 +73,7 @@ set(common_private_headers
   i18n.h
   password.h
   perf_timer.h
+  spawn.h
   stack_trace.h
   threadpool.h
   updates.h

src/common/notify.cpp

@@ -29,12 +29,17 @@
 #include <boost/algorithm/string.hpp>
 #include "misc_log_ex.h"
 #include "file_io_utils.h"
-#include "exec.h"
+#include "spawn.h"
 #include "notify.h"
 
 namespace tools
 {
 
+/*
+  TODO: 
+  - Improve tokenization to handle paths containing whitespaces, quotes, etc.
+  - Windows unicode support (implies implementing unicode command line parsing code)
+*/
 Notify::Notify(const char *spec)
 {
   CHECK_AND_ASSERT_THROW_MES(spec, "Null spec");
@@ -51,11 +56,7 @@ int Notify::notify(const char *parameter)
   for (std::string &s: margs)
     boost::replace_all(s, "%s", parameter);
 
-  char **cargs = (char**)alloca(sizeof(char*) * (margs.size() + 1));
-  for (size_t n = 0; n < margs.size(); ++n)
-    cargs[n] = (char*)margs[n].c_str();
-  cargs[margs.size()] = NULL;
-  return tools::exec(filename.c_str(), cargs, false);
+  return tools::spawn(filename.c_str(), margs, false);
 }
 
 }

src/common/spawn.cpp

@@ -29,16 +29,68 @@
 #include <errno.h>
 #include <unistd.h>
 #include <sys/types.h>
+#ifdef _WIN32
+#include <boost/algorithm/string/join.hpp>
+#include <boost/scope_exit.hpp>
+#include <windows.h>
+#else
 #include <sys/wait.h>
+#endif
 
 #include "misc_log_ex.h"
-#include "exec.h"
+#include "spawn.h"
 
 namespace tools
 {
 
-int exec(const char *filename, char * const argv[], bool wait)
+int spawn(const char *filename, const std::vector<std::string>& args, bool wait)
 {
+#ifdef _WIN32
+  std::string joined = boost::algorithm::join(args, " ");
+  char *commandLine = !joined.empty() ? &joined[0] : nullptr;
+  STARTUPINFOA si = {};
+  si.cb = sizeof(si);
+  PROCESS_INFORMATION pi;
+  if (!CreateProcessA(filename, commandLine, nullptr, nullptr, false, 0, nullptr, nullptr, &si, &pi))
+  {
+    MERROR("CreateProcess failed. Error code " << GetLastError());
+    return -1;
+  }
+  
+  BOOST_SCOPE_EXIT(&pi)
+  {
+    CloseHandle(pi.hThread);
+    CloseHandle(pi.hProcess);
+  }
+  BOOST_SCOPE_EXIT_END
+
+  if (!wait)
+  {
+    return 0;
+  }
+
+  DWORD result = WaitForSingleObject(pi.hProcess, INFINITE);
+  if (result != WAIT_OBJECT_0)
+  {
+    MERROR("WaitForSingleObject failed. Result " << result << ", error code " << GetLastError());
+    return -1;
+  }
+
+  DWORD exitCode;
+  if (!GetExitCodeProcess(pi.hProcess, &exitCode))
+  {
+    MERROR("GetExitCodeProcess failed. Error code " << GetLastError());
+    return -1;
+  }
+
+  MINFO("Child exited with " << exitCode);
+  return static_cast<int>(exitCode);
+#else
+  char **argv = (char**)alloca(sizeof(char*) * (args.size() + 1));
+  for (size_t n = 0; n < args.size(); ++n)
+    argv[n] = (char*)args[n].c_str();
+  argv[args.size()] = NULL;
+
   pid_t pid = fork();
   if (pid < 0)
   {
@@ -83,6 +135,7 @@ int exec(const char *filename, char * const argv[], bool wait)
   }
   MERROR("Secret passage found");
   return -1;
+#endif
 }
 
 }

src/common/spawn.h

@@ -31,6 +31,6 @@
 namespace tools
 {
 
-int exec(const char *filename, char * const argv[], bool wait);
+int spawn(const char *filename, const std::vector<std::string>& args, bool wait);
 
 }