Fix bug #13735 with network streams on MS-Windows.

Revert changes to w32proc.c done since 2012-11-30T09:23:15Z!eliz@gnu.org.

Do NOT merge to trunk!

 src/w32proc.c (new_child): Remove the loop that attempted to salvage
 slots of dead processes.
 (new_child, delete_child, find_child_pid): Don't insist on
 procinfo.hProcess be NULL for a process slot to be considered
 inactive, or be non-NULL to be considered active.
 (reader_thread): Don't set the FILE_AT_EOF flag of a file
 descriptor if the corresponding child was deleted and its
 char_avail handle is NULL.
 (reap_subprocess): Don't reset the FILE_AT_EOF flag.
 (sys_select): Don't pass a NULL process handle to
 WaitForMultipleObjects.

Fixes: debbugs:13735 debbugs:13546

2 files changed, 17 insertions, 65 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 06207f6690e..4325d35adee 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,17 @@
 2013-02-17  Eli Zaretskii  <eliz@gnu.org>
 
+        * w32proc.c (new_child): Remove the loop that attempted to salvage
+        slots of dead processes.
+        (new_child, delete_child, find_child_pid): Don't insist on
+        procinfo.hProcess be NULL for a process slot to be considered
+        inactive, or be non-NULL to be considered active.
+        (reader_thread): Don't set the FILE_AT_EOF flag of a file
+        descriptor if the corresponding child was deleted and its
+        char_avail handle is NULL.
+        (reap_subprocess): Don't reset the FILE_AT_EOF flag.  (Bug#13546)
+        (sys_select): Don't pass a NULL process handle to
+        WaitForMultipleObjects.  (Bug#13735)
+
         * xdisp.c (x_draw_vertical_border): For a window that is neither
         the leftmost nor the rightmost, redraw both the left and the right
         vertical borders.  (Bug#13723)
diff --git a/src/w32proc.c b/src/w32proc.c
index ca2096aaa9d..3b4522bf16b 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -795,51 +795,9 @@ new_child (void)
   DWORD id;
 
   for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
-    if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess == NULL)
+    if (!CHILD_ACTIVE (cp))
       goto Initialize;
   if (child_proc_count == MAX_CHILDREN)
-    {
-      int i = 0;
-      child_process *dead_cp = NULL;
-
-      DebPrint (("new_child: No vacant slots, looking for dead processes\n"));
-      for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
-        if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess)
-          {
-            DWORD status = 0;
-
-            if (!GetExitCodeProcess (cp->procinfo.hProcess, &status))
-              {
-                DebPrint (("new_child.GetExitCodeProcess: error %lu for PID %lu\n",
-                           GetLastError (), cp->procinfo.dwProcessId));
-                status = STILL_ACTIVE;
-              }
-            if (status != STILL_ACTIVE
-                || WaitForSingleObject (cp->procinfo.hProcess, 0) == WAIT_OBJECT_0)
-              {
-                DebPrint (("new_child: Freeing slot of dead process %d, fd %d\n",
-                           cp->procinfo.dwProcessId, cp->fd));
-                CloseHandle (cp->procinfo.hProcess);
-                cp->procinfo.hProcess = NULL;
-                CloseHandle (cp->procinfo.hThread);
-                cp->procinfo.hThread = NULL;
-                /* Free up to 2 dead slots at a time, so that if we
-                   have a lot of them, they will eventually all be
-                   freed when the tornado ends.  */
-                if (i == 0)
-                  dead_cp = cp;
-                else
-                  break;
-                i++;
-              }
-          }
-      if (dead_cp)
-        {
-          cp = dead_cp;
-          goto Initialize;
-        }
-    }
-  if (child_proc_count == MAX_CHILDREN)
     return NULL;
   cp = &child_procs[child_proc_count++];
 
@@ -894,7 +852,7 @@ delete_child (child_process *cp)
     if (fd_info[i].cp == cp)
       emacs_abort ();
 
-  if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess == NULL)
+  if (!CHILD_ACTIVE (cp))
     return;
 
   /* reap thread if necessary */
@@ -938,8 +896,7 @@ delete_child (child_process *cp)
   if (cp == child_procs + child_proc_count - 1)
     {
       for (i = child_proc_count-1; i >= 0; i--)
-        if (CHILD_ACTIVE (&child_procs[i])
-            || child_procs[i].procinfo.hProcess != NULL)
+        if (CHILD_ACTIVE (&child_procs[i]))
           {
             child_proc_count = i + 1;
             break;
@@ -956,8 +913,7 @@ find_child_pid (DWORD pid)
   child_process *cp;
 
   for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
-    if ((CHILD_ACTIVE (cp) || cp->procinfo.hProcess != NULL)
-        && pid == cp->pid)
+    if (CHILD_ACTIVE (cp) && pid == cp->pid)
       return cp;
   return NULL;
 }
@@ -990,17 +946,6 @@ reader_thread (void *arg)
       else
         rc = _sys_read_ahead (cp->fd);
 
-      if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess && cp->fd >= 0)
-        {
-          /* Somebody already called delete_child on this child, since
-             only delete_child zeroes out cp->char_avail.  This means
-             no one will read from cp->fd and will not set the
-             FILE_AT_EOF flag, therefore preventing sys_select from
-             noticing that the process died.  Set the flag here
-             instead.  */
-          fd_info[cp->fd].flags |= FILE_AT_EOF;
-        }
-
       /* The name char_avail is a misnomer - it really just means the
          read-ahead has completed, whether successfully or not. */
       if (!SetEvent (cp->char_avail))
@@ -1168,11 +1113,6 @@ reap_subprocess (child_process *cp)
      register_child has not been called. */
   if (cp->fd == -1)
     delete_child (cp);
-  else
-    {
-      /* Reset the flag set by reader_thread.  */
-      fd_info[cp->fd].flags &= ~FILE_AT_EOF;
-    }
 }
 
 /* Wait for any of our existing child processes to die
@@ -1957,7 +1897,7 @@ count_children:
     /* Some child_procs might be sockets; ignore them.  Also some
        children may have died already, but we haven't finished reading
        the process output; ignore them too.  */
-    if ((CHILD_ACTIVE (cp) || cp->procinfo.hProcess)
+    if (CHILD_ACTIVE (cp) && cp->procinfo.hProcess
         && (cp->fd < 0
             || (fd_info[cp->fd].flags & FILE_SEND_SIGCHLD) == 0
             || (fd_info[cp->fd].flags & FILE_AT_EOF) != 0)