[newlib-cygwin] Cygwin: processes: fix handling of native Windows processes

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=448cf5aa4b429d5a9cebf92a0da4ab4b5b6d23fe

commit 448cf5aa4b429d5a9cebf92a0da4ab4b5b6d23fe
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Sat Feb 2 12:23:39 2019 +0100

    Cygwin: processes: fix handling of native Windows processes
    
    Since commit b5e1003722cb14235c4f166be72c09acdffc62ea, native
    Windows processes not started by Cygwin processes don't have a
    Cygwin PID anymore.  This breaks ps -W and kill -f <WINPID>.
    
    Introduce MAX_PID (65536 for now).
    
    Cygwin processes as well as native Windows processes started
    from a Cygwin process get a PID < MAX_PID.  All other native
    Windows processes get a faked Cygwin PID >= MAX_PID.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/external.cc | 12 ++++++++----
 winsup/cygwin/pinfo.cc    |  2 +-
 winsup/cygwin/pinfo.h     |  2 ++
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/winsup/cygwin/external.cc b/winsup/cygwin/external.cc
index 3a9130e..ae30695 100644
--- a/winsup/cygwin/external.cc
+++ b/winsup/cygwin/external.cc
@@ -63,19 +63,23 @@ fillout_pinfo (pid_t pid, int winpid)
       _pinfo *p = pids[i];
       i++;
 
+      /* Native Windows process not started from Cygwin have no procinfo
+	 attached.  They don't have a real Cygwin PID either.  We fake a
+	 Cygwin PID beyond MAX_PID. */
       if (!p)
 	{
-	  if (!nextpid && thispid != (DWORD) pid)
+	  if (!nextpid && thispid + MAX_PID != (DWORD) pid)
 	    continue;
-	  ep.pid = cygwin_pid (thispid);
+	  ep.pid = thispid + MAX_PID;
 	  ep.dwProcessId = thispid;
 	  ep.process_state = PID_IN_USE;
 	  ep.ctty = -1;
 	  break;
 	}
-      else if (nextpid || p->pid == pid || (winpid && thispid == (DWORD) pid))
+      else if (nextpid || p->pid == pid)
 	{
-	  ep.ctty = (p->ctty < 0 || iscons_dev (p->ctty)) ? p->ctty : device::minor (p->ctty);
+	  ep.ctty = (p->ctty < 0 || iscons_dev (p->ctty))
+		    ? p->ctty : device::minor (p->ctty);
 	  ep.pid = p->pid;
 	  ep.ppid = p->ppid;
 	  ep.dwProcessId = p->dwProcessId;
diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index 98168c7..c902577 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -241,7 +241,7 @@ create_cygwin_pid ()
       do
 	{
 	  pid = ((uint32_t) InterlockedIncrement (&cygwin_shared->pid_src))
-		% 65536;
+		% MAX_PID;
 	}
       while (pid < 2);
       __small_swprintf (sym_name, L"cygpid.%u", pid);
diff --git a/winsup/cygwin/pinfo.h b/winsup/cygwin/pinfo.h
index 81e10d3..a1e5afe 100644
--- a/winsup/cygwin/pinfo.h
+++ b/winsup/cygwin/pinfo.h
@@ -211,6 +211,8 @@ private:
   DWORD status_exit (DWORD);
 };
 
+#define MAX_PID 65536
+
 #define ISSTATE(p, f)	(!!((p)->process_state & f))
 #define NOTSTATE(p, f)	(!((p)->process_state & f))