From 442c1a6790e52baa0c081f310d4d9e9b6f1ff638 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 1 May 2017 14:02:49 +0200
Subject: Try to detect MSYS2 processes

---
 butl/buildfile   |  9 ++++++++-
 butl/process.cxx | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/butl/buildfile b/butl/buildfile
index 25354c8..53fa588 100644
--- a/butl/buildfile
+++ b/butl/buildfile
@@ -77,7 +77,14 @@ lib{butl}: cxx.export.poptions = "-I$out_root" "-I$src_root"
 liba{butl}: cxx.export.poptions += -DLIBBUTL_STATIC
 libs{butl}: cxx.export.poptions += -DLIBBUTL_SHARED
 
-if ($cxx.target.class != "windows")
+if ($cxx.target.class == "windows")
+{
+  if ($cxx.target.system == "mingw32")
+    cxx.libs += -lpsapi
+  else
+    cxx.libs += psapi.lib
+}
+else
   cxx.libs += -lpthread
 
 # Install into the butl/ subdirectory of, say, /usr/include/.
diff --git a/butl/process.cxx b/butl/process.cxx
index db529a6..940560c 100644
--- a/butl/process.cxx
+++ b/butl/process.cxx
@@ -12,6 +12,8 @@
 #else
 #  include <butl/win32-utility>
 
+#  include <psapi.h>     // EnumProcessModules(), etc
+
 #  include <io.h>        // _get_osfhandle(), _close()
 #  include <stdlib.h>    // _MAX_PATH
 #  include <sys/types.h> // stat
@@ -43,6 +45,8 @@
 #include <butl/fdstream>        // fdnull()
 #include <butl/process-details>
 
+#include <iostream>
+
 using namespace std;
 
 #ifdef _WIN32
@@ -1166,7 +1170,9 @@ namespace butl
       // be in the returned list if it has failed to initialize). With this
       // improvement we could then wait longer and try harder.
       //
-      for (size_t ret (0); ret != 20; ++ret)
+      optional<bool> msys; // Absent if we don't know.
+
+      for (size_t ret (0); ret != 5; ++ret)
       {
         if (!CreateProcess (
               batch != nullptr ? batch : pp.effect_string (),
@@ -1183,13 +1189,54 @@ namespace butl
 
         auto_handle (pi.hThread).reset (); // Close.
 
-        // Wait a bit (50ms) and check if the process has terminated. If it is
+        // Detect if this is an MSYS2 process by checking if the process has
+        // loaded msys-2.0.dll.
+        //
+        size_t wait (200);
+
+        if (!msys)
+        {
+          // Wait a bit for the process to load its DLLs.
+          //
+          if (WaitForSingleObject (pi.hProcess, 50) == WAIT_TIMEOUT)
+          {
+            wait -= 50;
+
+            DWORD mn;
+            HMODULE ms[32]; // Normally it is one of the first.
+
+            if (EnumProcessModules (pi.hProcess, ms, sizeof (ms), &mn))
+            {
+              for (DWORD i (0); !msys && i != mn / sizeof (HMODULE); ++i)
+              {
+                char p[_MAX_PATH + 1];
+                if (GetModuleFileNameExA (pi.hProcess, ms[i], p, sizeof (p)))
+                {
+                  size_t n (strlen (p));
+                  if (n >= 12 && casecmp (p + n - 12, "msys-2.0.dll") == 0)
+                    msys = true;
+                }
+              }
+
+              if (!msys)
+                msys = false;
+            }
+            // EnumProcessModules() failed (presumably because the process has
+            // already exited), fall through.
+          }
+          // Process exited, fall through.
+        }
+
+        if (msys && !*msys)
+          break;
+
+        // Wait a bit longer and check if the process has terminated. If it is
         // still running then we assume all is good. Otherwise, retry if this
         // is the DLL initialization error.
         //
         DWORD s;
-        if (WaitForSingleObject (pi.hProcess, 50) != WAIT_OBJECT_0 ||
-            !GetExitCodeProcess (pi.hProcess, &s)                  ||
+        if (WaitForSingleObject (pi.hProcess, wait) != WAIT_OBJECT_0 ||
+            !GetExitCodeProcess (pi.hProcess, &s)                    ||
             s != STATUS_DLL_INIT_FAILED)
           break;
       }
-- 
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