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This pulls out the implementation of an event pipe used to implement target async support in both linux-low.cc (gdbserver) and linux-nat.c (gdb). This will be used to replace the existing event pipe in linux-low.cc and linux-nat.c in future commits. Co-Authored-By: Lancelot SIX <lsix@lancelotsix.com>gdb-12-branch
John Baldwin
5 years ago
6 changed files with 190 additions and 3 deletions
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/* Event pipe for GDB, the GNU debugger.
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Copyright (C) 2021 Free Software Foundation, Inc. |
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This file is part of GDB. |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "gdbsupport/common-defs.h" |
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#include "gdbsupport/event-pipe.h" |
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#include "gdbsupport/filestuff.h" |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <unistd.h> |
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event_pipe::~event_pipe () |
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{ |
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if (is_open ()) |
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close (); |
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} |
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/* See event-pipe.h. */ |
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bool |
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event_pipe::open () |
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{ |
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if (is_open ()) |
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return false; |
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if (gdb_pipe_cloexec (m_fds) == -1) |
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return false; |
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if (fcntl (m_fds[0], F_SETFL, O_NONBLOCK) == -1 |
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|| fcntl (m_fds[1], F_SETFL, O_NONBLOCK) == -1) |
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{ |
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close (); |
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return false; |
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} |
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return true; |
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} |
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/* See event-pipe.h. */ |
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void |
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event_pipe::close () |
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{ |
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::close (m_fds[0]); |
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::close (m_fds[1]); |
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m_fds[0] = -1; |
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m_fds[1] = -1; |
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} |
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/* See event-pipe.h. */ |
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void |
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event_pipe::flush () |
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{ |
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int ret; |
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char buf; |
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do |
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{ |
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ret = read (m_fds[0], &buf, 1); |
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} |
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while (ret >= 0 || (ret == -1 && errno == EINTR)); |
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} |
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/* See event-pipe.h. */ |
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void |
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event_pipe::mark () |
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{ |
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int ret; |
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/* It doesn't really matter what the pipe contains, as long we end
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up with something in it. Might as well flush the previous |
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left-overs. */ |
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flush (); |
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do |
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{ |
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ret = write (m_fds[1], "+", 1); |
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} |
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while (ret == -1 && errno == EINTR); |
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/* Ignore EAGAIN. If the pipe is full, the event loop will already
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be awakened anyway. */ |
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} |
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@ -0,0 +1,60 @@ |
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/* Event pipe for GDB, the GNU debugger.
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Copyright (C) 2021 Free Software Foundation, Inc. |
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This file is part of GDB. |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef COMMON_EVENT_PIPE_H |
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#define COMMON_EVENT_PIPE_H |
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/* An event pipe used as a waitable file in the event loop in place of
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some other event associated with a signal. The handler for the |
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signal marks the event pipe to force a wakeup in the event loop. |
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This uses the well-known self-pipe trick. */ |
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class event_pipe |
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{ |
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public: |
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event_pipe() = default; |
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~event_pipe(); |
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DISABLE_COPY_AND_ASSIGN (event_pipe); |
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/* Create a new pipe. */ |
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bool open (); |
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/* Close the pipe. */ |
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void close (); |
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/* True if the event pipe has been opened. */ |
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bool is_open () const |
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{ return m_fds[0] != -1; } |
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/* The file descriptor of the waitable file to use in the event
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loop. */ |
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int event_fd () const |
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{ return m_fds[0]; } |
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/* Flush the event pipe. */ |
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void flush (); |
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/* Put something in the pipe, so the event loop wakes up. */ |
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void mark (); |
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private: |
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int m_fds[2] = { -1, -1 }; |
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}; |
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#endif /* COMMON_EVENT_PIPE_H */ |
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