From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7868) id C9B743858C78; Tue, 1 Mar 2022 10:43:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C9B743858C78 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable From: Takashi Yano To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin] Cygwin: pty: Avoid cutting the branch the pty master is sitting on. X-Act-Checkin: newlib-cygwin X-Git-Author: Takashi Yano X-Git-Refname: refs/heads/master X-Git-Oldrev: 644e8bba07cdb6ca47ebafc766b52951860721d4 X-Git-Newrev: fbfea31dd9b9ecc4ffb160d91bb046688c3544b9 Message-Id: <20220301104332.C9B743858C78@sourceware.org> Date: Tue, 1 Mar 2022 10:43:32 +0000 (GMT) X-BeenThere: cygwin-cvs@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component git logs List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Mar 2022 10:43:32 -0000 https://sourceware.org/git/gitweb.cgi?p=3Dnewlib-cygwin.git;h=3Dfbfea31dd9b= 9ecc4ffb160d91bb046688c3544b9 commit fbfea31dd9b9ecc4ffb160d91bb046688c3544b9 Author: Takashi Yano Date: Tue Mar 1 11:34:16 2022 +0900 Cygwin: pty: Avoid cutting the branch the pty master is sitting on. =20 - 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: --- winsup/cygwin/exceptions.cc | 3 ++ winsup/cygwin/fhandler.h | 2 + winsup/cygwin/fhandler_termios.cc | 20 ++++++--- winsup/cygwin/fhandler_tty.cc | 87 +++++++++++++++++++----------------= ---- winsup/cygwin/sigproc.cc | 3 +- 5 files changed, 65 insertions(+), 50 deletions(-) diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc index 070e52e76..f946bed77 100644 --- a/winsup/cygwin/exceptions.cc +++ b/winsup/cygwin/exceptions.cc @@ -1157,6 +1157,9 @@ ctrl_c_handler (DWORD type) =20 tty_min *t =3D cygwin_shared->tty.get_cttyp (); =20 + 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 abd62d72a..7646f09cc 100644 --- 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); }; =20 #define __ptsname(buf, unit) __small_sprintf ((buf), "/dev/pty%d", (unit)) diff --git a/winsup/cygwin/fhandler_termios.cc b/winsup/cygwin/fhandler_ter= mios.cc index f83770e66..094842038 100644 --- a/winsup/cygwin/fhandler_termios.cc +++ b/winsup/cygwin/fhandler_termios.cc @@ -357,6 +357,7 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fhan= dler_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 =3D fhandler_console::exists (); pinfo pinfo_resume =3D pinfo (myself->ppid); DWORD resume_pid =3D 0; if (pinfo_resume) @@ -364,11 +365,12 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fh= andler_termios *fh) else resume_pid =3D 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 =3D=3D myself && being_debugged ()) { /* Avoid deadlock in gdb on console. */ @@ -388,11 +390,19 @@ fhandler_termios::process_sigs (char c, tty* ttyp, fh= andler_termios *fh) GenerateConsoleCtrlEvent (CTRL_C_EVENT, 0); ctrl_c_event_sent =3D 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 =3D true; } diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc index dde77ccf2..7b099dcb9 100644 --- a/winsup/cygwin/fhandler_tty.cc +++ b/winsup/cygwin/fhandler_tty.cc @@ -537,7 +537,8 @@ fhandler_pty_master::accept_input () resume_pid =3D pinfo_resume->dwProcessId; else resume_pid =3D get_console_process_id (myself->dwProcessId, false); - if (target_pid && resume_pid) + bool console_exists =3D 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 =3D 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 =3D=3D 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 =3D 0; + if (get_ttyp ()->invisible_console_pid + && !pinfo (get_ttyp ()->invisible_console_pid)) + get_ttyp ()->invisible_console_pid =3D 0; return 0; } =20 @@ -1122,7 +1124,7 @@ pcon_pid_alive (DWORD pid) inline static bool pcon_pid_self (DWORD pid) { - return (pid =3D=3D myself->exec_dwProcessId); + return (pid =3D=3D (myself->exec_dwProcessId ?: myself->dwProcessId)); } =20 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 mas= ter_fwd_thread_param_t *p) resume_pid =3D pinfo_resume->dwProcessId; else resume_pid =3D get_console_process_id (myself->dwProcessId, false); - if (target_pid && resume_pid) + bool console_exists =3D 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 mas= ter_fwd_thread_param_t *p) AttachConsole (target_pid); cp_from =3D 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; } =20 @@ -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); =20 /* Terminate helper process */ SetEvent (goodbye); @@ -3531,6 +3535,8 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, D= WORD force_switch_to) /* Search another process which attaches to the pseudo console */ DWORD current_pid =3D myself->exec_dwProcessId ?: myself->dwProcessI= d; switch_to =3D get_console_process_id (current_pid, false, true, true= ); + if (!switch_to) + switch_to =3D 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 =3D 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 =3D (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 =3D false; get_ttyp ()->invisible_console_pid =3D 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 =3D 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 =3D=3D tty::to_nat); } + +void +fhandler_pty_slave::close_pseudoconsole_if_necessary (tty *ttyp, + fhandler_termios *fh) +{ + if (fh->get_major () =3D=3D DEV_PTYM_MAJOR && ttyp->pcon_activated) + { + fhandler_pty_master *ptym =3D (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 4d7d273ae..edfdffd7c 100644 --- a/winsup/cygwin/sigproc.cc +++ b/winsup/cygwin/sigproc.cc @@ -1392,7 +1392,8 @@ wait_sig (VOID *) sig_held =3D true; break; case __SIGSETPGRP: - init_console_handler (true); + init_console_handler (::cygheap->ctty + && ::cygheap->ctty->is_console ()); break; case __SIGTHREADEXIT: {