https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=0f5046ef9f9d48aaaed283e019c20b2265121e69
commit 0f5046ef9f9d48aaaed283e019c20b2265121e69 Author: Takashi Yano <[email protected]> Date: Mon May 9 00:37:38 2022 +0900 Cygwin: pty: Avoid deadlock when pcon is started on console. - Previously, "env SHELL=cmd script" command in console caused deadlock when starting cmd.exe. This patch fixes the issue. Diff: --- winsup/cygwin/fhandler_tty.cc | 18 ++++++++++++------ winsup/cygwin/select.cc | 2 -- winsup/cygwin/tty.cc | 4 ++-- 3 files changed, 14 insertions(+), 10 deletions(-) diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc index b419cbdd0..31f399f99 100644 --- a/winsup/cygwin/fhandler_tty.cc +++ b/winsup/cygwin/fhandler_tty.cc @@ -248,9 +248,7 @@ atexit_func (void) ReleaseMutex (ptys->input_mutex); } WaitForSingleObject (ptys->pcon_mutex, INFINITE); - acquire_attach_mutex (mutex_timeout); ptys->close_pseudoconsole (ttyp, force_switch_to); - release_attach_mutex (); ReleaseMutex (ptys->pcon_mutex); break; } @@ -1176,9 +1174,7 @@ fhandler_pty_slave::reset_switch_to_pcon (void) return; bool need_restore_handles = get_ttyp ()->pcon_activated; WaitForSingleObject (pcon_mutex, INFINITE); - acquire_attach_mutex (mutex_timeout); close_pseudoconsole (get_ttyp ()); - release_attach_mutex (); ReleaseMutex (pcon_mutex); if (need_restore_handles) { @@ -3319,9 +3315,11 @@ fhandler_pty_slave::setup_pseudoconsole (bool nopcon) GetCurrentProcess (), &hpConOut, 0, TRUE, DUPLICATE_SAME_ACCESS); CloseHandle (pcon_owner); + acquire_attach_mutex (mutex_timeout); FreeConsole (); AttachConsole (get_ttyp ()->pcon_pid); init_console_handler (false); + release_attach_mutex (); goto skip_create; } @@ -3443,9 +3441,11 @@ fhandler_pty_slave::setup_pseudoconsole (bool nopcon) HeapFree (GetProcessHeap (), 0, si.lpAttributeList); /* Attach to pseudo console */ + acquire_attach_mutex (mutex_timeout); FreeConsole (); AttachConsole (pi.dwProcessId); init_console_handler (false); + release_attach_mutex (); /* Terminate helper process */ SetEvent (goodbye); @@ -3585,8 +3585,10 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to) } if (ttyp->pcon_activated) { + acquire_attach_mutex (mutex_timeout); ttyp->previous_code_page = GetConsoleCP (); ttyp->previous_output_code_page = GetConsoleOutputCP (); + release_attach_mutex (); if (pcon_pid_self (ttyp->pcon_pid)) { if (switch_to) @@ -3628,19 +3630,23 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to) ttyp->h_pcon_conhost_process = new_conhost_process; ttyp->h_pcon_in = new_pcon_in; ttyp->h_pcon_out = new_pcon_out; + acquire_attach_mutex (mutex_timeout); FreeConsole (); pinfo p (myself->ppid); if (!p || !AttachConsole (p->dwProcessId)) AttachConsole (ATTACH_PARENT_PROCESS); init_console_handler (false); + release_attach_mutex (); } else { /* Close pseudo console */ + acquire_attach_mutex (mutex_timeout); FreeConsole (); pinfo p (myself->ppid); if (!p || !AttachConsole (p->dwProcessId)) AttachConsole (ATTACH_PARENT_PROCESS); init_console_handler (false); + release_attach_mutex (); /* Reconstruct pseudo console handler container here for close */ HPCON_INTERNAL *hp = (HPCON_INTERNAL *) HeapAlloc (GetProcessHeap (), 0, @@ -3660,11 +3666,13 @@ fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to) } else { + acquire_attach_mutex (mutex_timeout); FreeConsole (); pinfo p (myself->ppid); if (!p || !AttachConsole (p->dwProcessId)) AttachConsole (ATTACH_PARENT_PROCESS); init_console_handler (false); + release_attach_mutex (); } } else if (pcon_pid_self (ttyp->pcon_pid)) @@ -4085,9 +4093,7 @@ fhandler_pty_slave::setup_for_non_cygwin_app (bool nopcon, PWCHAR envblock, if (disable_pcon || !term_has_pcon_cap (envblock)) nopcon = true; WaitForSingleObject (pcon_mutex, INFINITE); - acquire_attach_mutex (mutex_timeout); bool enable_pcon = setup_pseudoconsole (nopcon); - release_attach_mutex (); ReleaseMutex (pcon_mutex); /* For pcon enabled case, transfer_input() is called in master::write() */ if (!enable_pcon && get_ttyp ()->getpgid () == myself->pgid diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc index 29a89a0e4..a84d5a21c 100644 --- a/winsup/cygwin/select.cc +++ b/winsup/cygwin/select.cc @@ -1125,7 +1125,6 @@ peek_console (select_record *me, bool) { if (fh->bg_check (SIGTTIN, true) <= bg_eof) { - release_attach_mutex (); fh->release_input_mutex (); return me->read_ready = true; } @@ -1142,7 +1141,6 @@ peek_console (select_record *me, bool) && global_sigs[SIGWINCH].sa_handler != SIG_DFL) { set_sig_errno (EINTR); - release_attach_mutex (); fh->release_input_mutex (); return -1; } diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc index 44be3c8b4..f64c27719 100644 --- a/winsup/cygwin/tty.cc +++ b/winsup/cygwin/tty.cc @@ -335,6 +335,7 @@ tty_min::setpgid (int pid) { bool attach_restore = false; HANDLE from = ptys->get_handle_nat (); + WaitForSingleObject (ptys->input_mutex, mutex_timeout); acquire_attach_mutex (mutex_timeout); if (ttyp->pcon_activated && ttyp->pcon_pid && !ptys->get_console_process_id (ttyp->pcon_pid, true)) @@ -350,10 +351,8 @@ tty_min::setpgid (int pid) init_console_handler (false); attach_restore = true; } - WaitForSingleObject (ptys->input_mutex, mutex_timeout); fhandler_pty_slave::transfer_input (tty::to_cyg, from, ttyp, ptys->get_input_available_event ()); - ReleaseMutex (ptys->input_mutex); if (attach_restore) { FreeConsole (); @@ -363,6 +362,7 @@ tty_min::setpgid (int pid) init_console_handler (false); } release_attach_mutex (); + ReleaseMutex (ptys->input_mutex); } ReleaseMutex (ptys->pcon_mutex); }
