Previously, opening /dev/ptmx fails without setting errno when it is opened too many times. With this patch, return EMFILE in that situation.
Addresses: https://cygwin.com/pipermail/cygwin/2025-March/257786.html Fixes: 09738c30627c ("Cygwin: pty: setup new pty on opening the master, not in constructor") Reported-by: Christian Franke <christian.fra...@t-online.de> Signed-off-by: Takashi Yano <takashi.y...@nifty.ne.jp> (cherry picked from commit 7fc7d8b1d4e323a531ab2e71581263a0675072d8) --- winsup/cygwin/fhandler/pty.cc | 3 +++ winsup/cygwin/release/3.6.1 | 3 +++ winsup/cygwin/tty.cc | 2 +- 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/winsup/cygwin/fhandler/pty.cc b/winsup/cygwin/fhandler/pty.cc index e61a1c89b..3128b92da 100644 --- a/winsup/cygwin/fhandler/pty.cc +++ b/winsup/cygwin/fhandler/pty.cc @@ -1933,7 +1933,10 @@ int fhandler_pty_master::open (int flags, mode_t) { if (!setup ()) + { + set_errno (EMFILE); return 0; + } set_open_status (); dwProcessId = GetCurrentProcessId (); return 1; diff --git a/winsup/cygwin/release/3.6.1 b/winsup/cygwin/release/3.6.1 index 254cfdd9c..491d7dcb9 100644 --- a/winsup/cygwin/release/3.6.1 +++ b/winsup/cygwin/release/3.6.1 @@ -27,3 +27,6 @@ Fixes: - Accommodate a change in Windows exception handling affecting software generated exceptions. Addresses: https://cygwin.com/pipermail/cygwin/2025-March/257808.html + +- Return EMFILE when opening /dev/ptmx too many times. + Addresses: https://cygwin.com/pipermail/cygwin/2025-March/257786.html diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc index 2cd4ae6ed..a4b716721 100644 --- a/winsup/cygwin/tty.cc +++ b/winsup/cygwin/tty.cc @@ -147,7 +147,7 @@ tty_list::allocate (HANDLE& r, HANDLE& w) termios_printf ("pty%d allocated", freetty); else { - system_printf ("No pty allocated"); + termios_printf ("No pty allocated"); r = w = NULL; } -- 2.45.1
