Cygwin: pty: Avoid cutting the branch the pty master is sitting on.

- When Ctrl-C terminates a non-cygwin process on a pseudo console,
  pty master attaches to the pseudo console first, and send
  CTRL_C_EVENT. If the non-cygwin process closes the pseudo console
  before the pty master calls FreeConsole(), the pty master process
  will crash. With this patch, pty master process takes over the
  ownership of the pseudo console, and closes it by myself.

diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index 070e52e76723789db9f09ee456eaf1477a4d2ec3..f946bed77cffb0a666c7056a7f731abdafa585cc 100644 (file)
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1157,6 +1157,9 @@ ctrl_c_handler (DWORD type)
 
   tty_min *t = cygwin_shared->tty.get_cttyp ();
 
+  if (!t)
+    return TRUE;
+
   /* If process group leader is non-cygwin process or not exist,
      send signal to myself. */
   pinfo pi (t->getpgid ());

diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index abd62d72a93cf8332e13a6a073bac4f1d72f72e3..7646f09ccb8d62948cd8b1b35693981f0ab5029c 100644 (file)
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -2409,6 +2409,8 @@ class fhandler_pty_slave: public fhandler_pty_common
   static void cleanup_for_non_cygwin_app (handle_set_t *p, tty *ttyp,
                                          bool stdin_is_ptys);
   void setpgid_aux (pid_t pid);
+  static void close_pseudoconsole_if_necessary (tty *ttyp,
+                                               fhandler_termios *fh);
 };
 
 #define __ptsname(buf, unit) __small_sprintf ((buf), "/dev/pty%d", (unit))

diff --git a/winsup/cygwin/fhandler_termios.cc b/winsup/cygwin/fhandler_termios.cc
index f83770e664a9e0cc1d135238a57d39510c245475..09484203846b66edf691397d0183ff8d80992ac9 100644 (file)
--- a/winsup/cygwin/fhandler_termios.cc
+++ b/winsup/cygwin/fhandler_termios.cc
@@ -357,6 +357,7 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fhandler_termios *fh)
             which the target process is attaching before sending the
             CTRL_C_EVENT. After sending the event, reattach to the
             console to which the process was previously attached.  */
+         bool console_exists = fhandler_console::exists ();
          pinfo pinfo_resume = pinfo (myself->ppid);
          DWORD resume_pid = 0;
          if (pinfo_resume)
@@ -364,11 +365,12 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fhandler_termios *fh)
          else
            resume_pid = fhandler_pty_common::get_console_process_id
              (myself->dwProcessId, false);
-         if (resume_pid && fh && !fh->is_console ())
+         if ((!console_exists || resume_pid) && fh && !fh->is_console ())
            {
              FreeConsole ();
              AttachConsole (p->dwProcessId);
-             init_console_handler (true);
+             init_console_handler (::cygheap->ctty
+                                   && ::cygheap->ctty->is_console ());
            }
          if (fh && p == myself && being_debugged ())
            { /* Avoid deadlock in gdb on console. */
@@ -388,11 +390,19 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fhandler_termios *fh)
              GenerateConsoleCtrlEvent (CTRL_C_EVENT, 0);
              ctrl_c_event_sent = true;
            }
-         if (resume_pid && fh && !fh->is_console ())
+         if ((!console_exists || resume_pid) && fh && !fh->is_console ())
            {
+             /* If a process on pseudo console is killed by Ctrl-C,
+                this process may take over the ownership of the
+                pseudo console because this process attached to it
+                before sending CTRL_C_EVENT. In this case, closing
+                pseudo console is necessary. */
+             fhandler_pty_slave::close_pseudoconsole_if_necessary (ttyp, fh);
              FreeConsole ();
-             AttachConsole (resume_pid);
-             init_console_handler (true);
+             if (resume_pid && console_exists)
+               AttachConsole (resume_pid);
+             init_console_handler (::cygheap->ctty
+                                   && ::cygheap->ctty->is_console ());
            }
          need_discard_input = true;
        }

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index dde77ccf2277ed80d0791b2976e1851bd0ad64e3..7b099dcb931480cabe68a2443e90c8f7e2a65e1c 100644 (file)
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -537,7 +537,8 @@ fhandler_pty_master::accept_input ()
        resume_pid = pinfo_resume->dwProcessId;
       else
        resume_pid = get_console_process_id (myself->dwProcessId, false);
-      if (target_pid && resume_pid)
+      bool console_exists = fhandler_console::exists ();
+      if (target_pid && (resume_pid || !console_exists))
        {
          /* Slave attaches to a different console than master.
             Therefore reattach here. */
@@ -546,8 +547,9 @@ fhandler_pty_master::accept_input ()
          AttachConsole (target_pid);
          cp_to = GetConsoleCP ();
          FreeConsole ();
-         AttachConsole (resume_pid);
-         init_console_handler (true);
+         if (resume_pid && console_exists)
+           AttachConsole (resume_pid);
+         init_console_handler (false);
          release_attach_mutex ();
        }
       else
@@ -1029,12 +1031,12 @@ fhandler_pty_slave::close ()
   if (!ForceCloseHandle (get_handle_nat ()))
     termios_printf ("CloseHandle (get_handle_nat ()<%p>), %E",
        get_handle_nat ());
-  if ((unsigned) myself->ctty == FHDEV (DEV_PTYS_MAJOR, get_minor ()))
-    fhandler_console::free_console (); /* assumes that we are the last pty closer */
   fhandler_pty_common::close ();
   if (!ForceCloseHandle (output_mutex))
     termios_printf ("CloseHandle (output_mutex<%p>), %E", output_mutex);
-  get_ttyp ()->invisible_console_pid = 0;
+  if (get_ttyp ()->invisible_console_pid
+      && !pinfo (get_ttyp ()->invisible_console_pid))
+    get_ttyp ()->invisible_console_pid = 0;
   return 0;
 }
 
@@ -1122,7 +1124,7 @@ pcon_pid_alive (DWORD pid)
 inline static bool
 pcon_pid_self (DWORD pid)
 {
-  return (pid == myself->exec_dwProcessId);
+  return (pid == (myself->exec_dwProcessId ?: myself->dwProcessId));
 }
 
 void
@@ -1240,14 +1242,14 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
                                       0, TRUE, DUPLICATE_SAME_ACCESS);
                      FreeConsole ();
                      AttachConsole (get_ttyp ()->pcon_pid);
-                     init_console_handler (true);
+                     init_console_handler (false);
                      WaitForSingleObject (input_mutex, mutex_timeout);
                      transfer_input (tty::to_cyg, h_pcon_in, get_ttyp (),
                                      input_available_event);
                      ReleaseMutex (input_mutex);
                      FreeConsole ();
                      AttachConsole (resume_pid);
-                     init_console_handler (true);
+                     init_console_handler (false);
                      CloseHandle (h_pcon_in);
                    }
                  CloseHandle (pcon_owner);
@@ -2839,7 +2841,8 @@ fhandler_pty_master::pty_master_fwd_thread (const master_fwd_thread_param_t *p)
        resume_pid = pinfo_resume->dwProcessId;
       else
        resume_pid = get_console_process_id (myself->dwProcessId, false);
-      if (target_pid && resume_pid)
+      bool console_exists = fhandler_console::exists ();
+      if (target_pid && (resume_pid || !console_exists))
        {
          /* Slave attaches to a different console than master.
             Therefore reattach here. */
@@ -2848,8 +2851,9 @@ fhandler_pty_master::pty_master_fwd_thread (const master_fwd_thread_param_t *p)
          AttachConsole (target_pid);
          cp_from = GetConsoleOutputCP ();
          FreeConsole ();
-         AttachConsole (resume_pid);
-         init_console_handler (true);
+         if (resume_pid && console_exists)
+           AttachConsole (resume_pid);
+         init_console_handler (false);
          release_attach_mutex ();
        }
       else
@@ -3272,7 +3276,7 @@ fhandler_pty_slave::setup_pseudoconsole (bool nopcon)
       CloseHandle (pcon_owner);
       FreeConsole ();
       AttachConsole (get_ttyp ()->pcon_pid);
-      init_console_handler (true);
+      init_console_handler (false);
       goto skip_create;
     }
 
@@ -3396,7 +3400,7 @@ fhandler_pty_slave::setup_pseudoconsole (bool nopcon)
       /* Attach to pseudo console */
       FreeConsole ();
       AttachConsole (pi.dwProcessId);
-      init_console_handler (true);
+      init_console_handler (false);
 
       /* Terminate helper process */
       SetEvent (goodbye);
@@ -3531,6 +3535,8 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to)
       /* Search another process which attaches to the pseudo console */
       DWORD current_pid = myself->exec_dwProcessId ?: myself->dwProcessId;
       switch_to = get_console_process_id (current_pid, false, true, true);
+      if (!switch_to)
+       switch_to = get_console_process_id (current_pid, false, true, false);
     }
   if (ttyp->pcon_activated)
     {
@@ -3579,27 +3585,17 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to)
              ttyp->h_pcon_out = new_pcon_out;
              FreeConsole ();
              pinfo p (myself->ppid);
-             if (p)
-               {
-                 if (!AttachConsole (p->dwProcessId))
-                   AttachConsole (ATTACH_PARENT_PROCESS);
-               }
-             else
+             if (!p || !AttachConsole (p->dwProcessId))
                AttachConsole (ATTACH_PARENT_PROCESS);
-             init_console_handler (true);
+             init_console_handler (false);
            }
          else
            { /* Close pseudo console */
              FreeConsole ();
              pinfo p (myself->ppid);
-             if (p)
-               {
-                 if (!AttachConsole (p->dwProcessId))
-                   AttachConsole (ATTACH_PARENT_PROCESS);
-               }
-             else
+             if (!p || !AttachConsole (p->dwProcessId))
                AttachConsole (ATTACH_PARENT_PROCESS);
-             init_console_handler (true);
+             init_console_handler (false);
              /* Reconstruct pseudo console handler container here for close */
              HPCON_INTERNAL *hp =
                (HPCON_INTERNAL *) HeapAlloc (GetProcessHeap (), 0,
@@ -3621,14 +3617,9 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to)
        {
          FreeConsole ();
          pinfo p (myself->ppid);
-         if (p)
-           {
-             if (!AttachConsole (p->dwProcessId))
-               AttachConsole (ATTACH_PARENT_PROCESS);
-           }
-         else
+         if (!p || !AttachConsole (p->dwProcessId))
            AttachConsole (ATTACH_PARENT_PROCESS);
-         init_console_handler (true);
+         init_console_handler (false);
        }
     }
   else if (pcon_pid_self (ttyp->pcon_pid))
@@ -3795,7 +3786,7 @@ fhandler_pty_slave::create_invisible_console ()
       /* Detach from console device and create new invisible console. */
       FreeConsole();
       fhandler_console::need_invisible (true);
-      init_console_handler (true);
+      init_console_handler (false);
       get_ttyp ()->need_invisible_console = false;
       get_ttyp ()->invisible_console_pid = myself->pid;
     }
@@ -4102,7 +4093,7 @@ fhandler_pty_slave::setpgid_aux (pid_t pid)
          CloseHandle (pcon_owner);
          FreeConsole ();
          AttachConsole (get_ttyp ()->pcon_pid);
-         init_console_handler (true);
+         init_console_handler (false);
          attach_restore = true;
        }
       WaitForSingleObject (input_mutex, mutex_timeout);
@@ -4112,14 +4103,9 @@ fhandler_pty_slave::setpgid_aux (pid_t pid)
        {
          FreeConsole ();
          pinfo p (myself->ppid);
-         if (p)
-           {
-             if (!AttachConsole (p->dwProcessId))
-               AttachConsole (ATTACH_PARENT_PROCESS);
-           }
-         else
+         if (!p || !AttachConsole (p->dwProcessId))
            AttachConsole (ATTACH_PARENT_PROCESS);
-         init_console_handler (true);
+         init_console_handler (false);
        }
     }
   ReleaseMutex (pcon_mutex);
@@ -4135,3 +4121,16 @@ fhandler_pty_master::need_send_ctrl_c_event ()
   return !(to_be_read_from_pcon () && get_ttyp ()->pcon_activated
     && get_ttyp ()->pcon_input_state == tty::to_nat);
 }
+
+void
+fhandler_pty_slave::close_pseudoconsole_if_necessary (tty *ttyp,
+                                                     fhandler_termios *fh)
+{
+  if (fh->get_major () == DEV_PTYM_MAJOR && ttyp->pcon_activated)
+    {
+      fhandler_pty_master *ptym = (fhandler_pty_master *) fh;
+      WaitForSingleObject (ptym->pcon_mutex, INFINITE);
+      close_pseudoconsole (ttyp);
+      ReleaseMutex (ptym->pcon_mutex);
+    }
+}

diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index 4d7d273aee756f8bc4a8627b29d0d205f3d1a7fd..edfdffd7c28e2a4d0c5e9c153df1814a5222e0fd 100644 (file)
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -1392,7 +1392,8 @@ wait_sig (VOID *)
          sig_held = true;
          break;
        case __SIGSETPGRP:
-         init_console_handler (true);
+         init_console_handler (::cygheap->ctty
+                               && ::cygheap->ctty->is_console ());
          break;
        case __SIGTHREADEXIT:
          {