| /* Serial interface for a selectable event. |
| Copyright (C) 2016-2024 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "ser-event.h" |
| #include "serial.h" |
| #include "gdbsupport/filestuff.h" |
| |
| /* On POSIX hosts, a serial_event is basically an abstraction for the |
| classical self-pipe trick. |
| |
| On Windows, a serial_event is a wrapper around a native Windows |
| event object. Because we want to interface with gdb_select, which |
| takes file descriptors, we need to wrap that Windows event object |
| in a file descriptor. As _open_osfhandle can not be used with |
| event objects, we instead create a dummy file wrap that in a file |
| descriptor with _open_osfhandle, and pass that as selectable |
| descriptor to callers. As Windows' gdb_select converts file |
| descriptors back to Windows handles by calling serial->wait_handle, |
| nothing ever actually waits on that file descriptor. */ |
| |
| struct serial_event_state |
| { |
| #ifdef USE_WIN32API |
| /* The Windows event object, created with CreateEvent. */ |
| HANDLE event; |
| #else |
| /* The write side of the pipe. The read side is in |
| serial->fd. */ |
| int write_fd; |
| #endif |
| }; |
| |
| /* Open a new serial event. */ |
| |
| static void |
| serial_event_open (struct serial *scb, const char *name) |
| { |
| struct serial_event_state *state; |
| |
| state = XNEW (struct serial_event_state); |
| scb->state = state; |
| |
| #ifndef USE_WIN32API |
| { |
| int fds[2]; |
| |
| if (gdb_pipe_cloexec (fds) == -1) |
| internal_error ("creating serial event pipe failed."); |
| |
| fcntl (fds[0], F_SETFL, O_NONBLOCK); |
| fcntl (fds[1], F_SETFL, O_NONBLOCK); |
| |
| scb->fd = fds[0]; |
| state->write_fd = fds[1]; |
| } |
| #else |
| { |
| /* A dummy file object that can be wrapped in a file descriptor. |
| We don't need to store this handle because closing the file |
| descriptor automatically closes this. */ |
| HANDLE dummy_file; |
| |
| /* A manual-reset event. */ |
| state->event = CreateEvent (0, TRUE, FALSE, 0); |
| |
| /* The dummy file handle. Created just so we have something |
| wrappable in a file descriptor. */ |
| dummy_file = CreateFile ("nul", 0, 0, NULL, OPEN_EXISTING, 0, NULL); |
| scb->fd = _open_osfhandle ((intptr_t) dummy_file, 0); |
| } |
| #endif |
| } |
| |
| static void |
| serial_event_close (struct serial *scb) |
| { |
| struct serial_event_state *state = (struct serial_event_state *) scb->state; |
| |
| close (scb->fd); |
| #ifndef USE_WIN32API |
| close (state->write_fd); |
| #else |
| CloseHandle (state->event); |
| #endif |
| |
| scb->fd = -1; |
| |
| xfree (state); |
| scb->state = NULL; |
| } |
| |
| #ifdef USE_WIN32API |
| |
| /* Implementation of the wait_handle method. Returns the native |
| Windows event object handle. */ |
| |
| static void |
| serial_event_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except) |
| { |
| struct serial_event_state *state = (struct serial_event_state *) scb->state; |
| |
| *read = state->event; |
| } |
| |
| #endif |
| |
| /* The serial_ops for struct serial_event objects. Note we never |
| register this serial type with serial_add_interface, because this |
| is internal implementation detail never to be used by remote |
| targets for protocol transport. */ |
| |
| static const struct serial_ops serial_event_ops = |
| { |
| "event", |
| serial_event_open, |
| serial_event_close, |
| NULL, /* fdopen */ |
| NULL, /* readchar */ |
| NULL, /* write */ |
| NULL, /* flush_output */ |
| NULL, /* flush_input */ |
| NULL, /* send_break */ |
| NULL, /* go_raw */ |
| NULL, /* get_tty_state */ |
| NULL, /* copy_tty_state */ |
| NULL, /* set_tty_state */ |
| NULL, /* print_tty_state */ |
| NULL, /* setbaudrate */ |
| NULL, /* setstopbits */ |
| NULL, /* setparity */ |
| NULL, /* drain_output */ |
| NULL, /* async */ |
| NULL, /* read_prim */ |
| NULL, /* write_prim */ |
| NULL, /* avail */ |
| #ifdef USE_WIN32API |
| serial_event_wait_handle, |
| #endif |
| }; |
| |
| /* See ser-event.h. */ |
| |
| struct serial_event * |
| make_serial_event (void) |
| { |
| return (struct serial_event *) serial_open_ops (&serial_event_ops); |
| } |
| |
| /* See ser-event.h. */ |
| |
| int |
| serial_event_fd (struct serial_event *event) |
| { |
| struct serial *ser = (struct serial *) event; |
| |
| return ser->fd; |
| } |
| |
| /* See ser-event.h. */ |
| |
| void |
| serial_event_set (struct serial_event *event) |
| { |
| struct serial *ser = (struct serial *) event; |
| struct serial_event_state *state = (struct serial_event_state *) ser->state; |
| #ifndef USE_WIN32API |
| int r; |
| char c = '+'; /* Anything. */ |
| |
| do |
| { |
| r = write (state->write_fd, &c, 1); |
| } |
| while (r < 0 && errno == EINTR); |
| #else |
| SetEvent (state->event); |
| #endif |
| } |
| |
| /* See ser-event.h. */ |
| |
| void |
| serial_event_clear (struct serial_event *event) |
| { |
| struct serial *ser = (struct serial *) event; |
| #ifndef USE_WIN32API |
| int r; |
| |
| do |
| { |
| char c; |
| |
| r = read (ser->fd, &c, 1); |
| } |
| while (r > 0 || (r < 0 && errno == EINTR)); |
| #else |
| struct serial_event_state *state = (struct serial_event_state *) ser->state; |
| ResetEvent (state->event); |
| #endif |
| } |