The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e671cd59d74cec9f53e110ce887128d1eeadb7f2

commit e671cd59d74cec9f53e110ce887128d1eeadb7f2
Author: Pedro Alves <palves@redhat.com>
Date:   Tue Jan 30 14:23:51 2018 +0000

    Per-inferior target_terminal state, fix PR gdb/13211, more
    
    In my multi-target branch I ran into problems with GDB's terminal
    handling that exist in master as well, with multi-inferior debugging.
    
    This patch adds a testcase for said problems
    (gdb.multi/multi-term-settings.exp), fixes the problems, fixes PR
    gdb/13211 as well (and adds a testcase for that too,
    gdb.base/interrupt-daemon.exp).
    
    The basis of the problem I ran into is the following.  Consider a
    scenario where you have:
    
     - inferior 1 - started with "attach", process is running on some
       other terminal.
    
     - inferior 2 - started with "run", process is sharing gdb's terminal.
    
    In this scenario, when you stop/resume both inferiors, you want GDB to
    save/restore the terminal settings of inferior 2, the one that is
    sharing GDB's terminal.  I.e., you want inferior 2 to "own" the
    terminal (in target_terminal::is_ours/target_terminal::is_inferior
    sense).
    
    Unfortunately, that's not what you get currently.  Because GDB doesn't
    know whether an attached inferior is actually sharing GDB's terminal,
    it tries to save/restore its settings anyway, ignoring errors.  In
    this case, this is pointless, because inferior 1 is running on a
    different terminal, but GDB doesn't know better.
    
    And then, because it is only possible to have the terminal settings of
    a single inferior be in effect at a time, or make one inferior/pgrp be
    the terminal's foreground pgrp (aka, only one inferior can "own" the
    terminal, ignoring fork children here), if GDB happens to try to
    restore the terminal settings of inferior 1 first, then GDB never
    restores the terminal settings of inferior 2.
    
    This patch fixes that and a few things more along the way:
    
     - Moves enum target_terminal::terminal_state out of the
       target_terminal class (it's currently private) and makes it a
       scoped enum so that it can be easily used elsewhere.
    
     - Replaces the inflow.c:terminal_is_ours boolean with a
       target_terminal_state variable.  This allows distinguishing is_ours
       and is_ours_for_output states.  This allows finally making
       child_terminal_ours_1 do something with its "output_only"
       parameter.
    
     - Makes each inferior have its own copy of the
       is_ours/is_ours_for_output/is_inferior state.
    
     - Adds a way for GDB to tell whether the inferior is sharing GDB's
       terminal.  Works best on Linux and Solaris; the fallback works just
       as well as currently.
    
     - With that, we can remove the inf->attach_flag tests from
       child_terminal_inferior/child_terminal_ours.
    
     - Currently target_ops.to_ours is responsible for both saving the
       current inferior's terminal state, and restoring gdb's state.
       Because each inferior has its own terminal state (possibly handled
       by different targets in a multi-target world, even), we need to
       split the inferior-saving part from the gdb-restoring part.  The
       patch adds a new target_ops.to_save_inferior target method for
       that.
    
     - Adds a new target_terminal::save_inferior() function, so that
       sequences like:
    
         scoped_restore_terminal_state save_state;
         target_terminal::ours_for_output ();
    
       ... restore back inferiors that were
       target_terminal_state::is_inferior before back to is_inferior, and
       leaves inferiors that were is_ours alone.
    
     - Along the way, this adds a default implementation of
       target_pass_ctrlc to inflow.c (for inf-child.c), that handles
       passing the Ctrl-C to a process running on GDB's terminal or to
       some other process otherwise.
    
     - Similarly, adds a new target default implementation of
       target_interrupt, for the "interrupt" command.  The current
       implementation of this hook in inf-ptrace.c kills the whole process
       group, but that's incorrect/undesirable because we may not be
       attached to all processes in the process group.  And also, it's
       incorrect because inferior_process_group() doesn't really return
       the inferior's real process group id if the inferior is not a
       process group leader...  This is the cause of PR gdb/13211 [1],
       which this patch fixes.  While at it, that target method's "ptid"
       parameter is eliminated, because it's not really used.
    
     - A new test is included that exercises and fixes PR gdb/13211, and
       also fixes a GDB issue reported on stackoverflow that I ran into
       while working on this [2].  The problem is similar to PR gdb/13211,
       except that it also triggers with Ctrl-C.  When debugging a daemon
       (i.e., a process that disconnects from the controlling terminal and
       is not a process group leader, then Ctrl-C doesn't work, you just
       can't interrupt the inferior at all, resulting in a hung debug
       session.  The problem is that since the inferior is no longer
       associated with gdb's session / controlling terminal, then trying
       to put the inferior in the foreground fails.  And so Ctrl-C never
       reaches the inferior directly.  pass_signal is only used when the
       inferior is attached, but that is not the case here.  This is fixed
       by the new child_pass_ctrlc.  Without the fix, the new
       interrupt-daemon.exp testcase fails with timeout waiting for a
       SIGINT that never arrives.
    
    [1] PR gdb/13211 - Async / Process group and interrupt not working
    https://sourceware.org/bugzilla/show_bug.cgi?id=13211
    
    [2] GDB not reacting Ctrl-C when after fork() and setsid()
    https://stackoverflow.com/questions/46101292/gdb-not-reacting-ctrl-c-when-after-fork-and-setsid
    
    Note this patch does _not_ fix:
    
     - PR gdb/14559 - The 'interrupt' command does not work if sigwait is in use
       https://sourceware.org/bugzilla/show_bug.cgi?id=14559
    
     - PR gdb/9425 - When using "sigwait" GDB doesn't trap SIGINT. Ctrl+C terminates program when should break gdb.
       https://sourceware.org/bugzilla/show_bug.cgi?id=9425
    
    The only way to fix that that I know of (without changing the kernel)
    is to make GDB put inferiors in a separate session (create a
    pseudo-tty master/slave pair, make the inferior run with the slave as
    its terminal, and have gdb pump output/input on the master end).
    
    gdb/ChangeLog:
    2018-01-30  Pedro Alves  <palves@redhat.com>
    
    	PR gdb/13211
    	* config.in, configure: Regenerate.
    	* configure.ac: Check for getpgid.
    	* go32-nat.c (go32_pass_ctrlc): New.
    	(go32_target): Install it.
    	* inf-child.c (inf_child_target): Install
    	child_terminal_save_inferior, child_pass_ctrlc and
    	child_interrupt.
    	* inf-ptrace.c (inf_ptrace_interrupt): Delete.
    	(inf_ptrace_target): No longer install it.
    	* infcmd.c (interrupt_target_1): Adjust.
    	* inferior.h (child_terminal_save_inferior, child_pass_ctrlc)
    	(child_interrupt): Declare.
    	(inferior::terminal_state): New.
    	* inflow.c (struct terminal_info): Update comments.
    	(inferior_process_group): Delete.
    	(terminal_is_ours): Delete.
    	(gdb_tty_state): New.
    	(child_terminal_init): Adjust.
    	(is_gdb_terminal, sharing_input_terminal_1)
    	(sharing_input_terminal): New functions.
    	(child_terminal_inferior): Adjust.  Use sharing_input_terminal.
    	Set the process's actual process group in the foreground if
    	possible.  Handle is_ours_for_output/is_ours distinction.  Don't
    	mark terminal as the inferior's if not sharing GDB's terminal.
    	Don't check attach_flag.
    	(child_terminal_ours_for_output, child_terminal_ours): Adjust to
    	pass down a target_terminal_state.
    	(child_terminal_save_inferior): New, factored out from ...
    	(child_terminal_ours_1): ... this.  Handle
    	target_terminal_state::is_ours_for_output.
    	(child_interrupt, child_pass_ctrlc): New.
    	(inflow_inferior_exit): Clear the inferior's terminal_state.
    	(copy_terminal_info): Copy the inferior's terminal state.
    	(_initialize_inflow): Remove reference to terminal_is_ours.
    	* inflow.h (inferior_process_group): Delete.
    	* nto-procfs.c (nto_handle_sigint, procfs_interrupt): Adjust.
    	* procfs.c (procfs_target): Don't install procfs_interrupt.
    	(procfs_interrupt): Delete.
    	* remote.c (remote_serial_quit_handler): Adjust.
    	(remote_interrupt): Remove ptid parameter.  Adjust.
    	* target-delegates.c: Regenerate.
    	* target.c: Include "terminal.h".
    	(target_terminal::terminal_state): Rename to ...
    	(target_terminal::m_terminal_state): ... this.
    	(target_terminal::init): Adjust.
    	(target_terminal::inferior): Adjust to per-inferior
    	terminal_state.
    	(target_terminal::restore_inferior, target_terminal_is_ours_kind): New.
    	(target_terminal::ours, target_terminal::ours_for_output): Use
    	target_terminal_is_ours_kind.
    	(target_interrupt): Remove ptid parameter.  Adjust.
    	(default_target_pass_ctrlc): Adjust.
    	* target.h (target_ops::to_terminal_save_inferior): New field.
    	(target_ops::to_interrupt): Remove ptid_t parameter.
    	(target_interrupt): Remove ptid_t parameter.  Update comment.
    	(target_pass_ctrlc): Update comment.
    	* target/target.h (target_terminal_state): New scoped enum,
    	factored out of ...
    	(target_terminal::terminal_state): ... here.
    	(target_terminal::inferior): Update comments.
    	(target_terminal::restore_inferior): New.
    	(target_terminal::is_inferior, target_terminal::is_ours)
    	(target_terminal::is_ours_for_output): Adjust.
    	(target_terminal::scoped_restore_terminal_state): Adjust to
    	rename, and call restore_inferior() instead of inferior().
    	(target_terminal::scoped_restore_terminal_state::m_state): Change
    	type.
    	(target_terminal::terminal_state): Rename to ...
    	(target_terminal::m_terminal_state): ... this and change type.
    
    gdb/gdbserver/ChangeLog:
    2018-01-30  Pedro Alves  <palves@redhat.com>
    
    	PR gdb/13211
    	* target.c (target_terminal::terminal_state): Rename to ...
    	(target_terminal::m_terminal_state): ... this.
    
    gdb/testsuite/ChangeLog:
    2018-01-30  Pedro Alves  <palves@redhat.com>
    
    	PR gdb/13211
    	* gdb.base/interrupt-daemon.c: New.
    	* gdb.base/interrupt-daemon.exp: New.
    	* gdb.multi/multi-term-settings.c: New.
    	* gdb.multi/multi-term-settings.exp: New.

The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f6cfb42730ed37bfb32cb27ef627df930f437f08

commit f6cfb42730ed37bfb32cb27ef627df930f437f08
Author: Pedro Alves <palves@redhat.com>
Date:   Wed Jan 31 13:45:06 2018 +0000

    gdb: Fix remote-sim/MinGW/Darwin builds
    
    The recent commit e671cd59 ("Per-inferior target_terminal state, fix
    PR gdb/13211, more") missed adjusting a few targets to the new
    target_ops->to_interrupt interface, breaking the build for those
    targets.  This fixes it.
    
    Note: remote-sim doesn't really support async execution, so I don't
    think gdbsim_interrupt is ever reached via target_interrupt.  (It is
    reached via gdbsim_cntrl_c though).
    
    The inflow.c changes are a bit ugly, but they're just doing what other
    parts of the file already do to handle the same missing functions.
    Targets that don't have 'kill', like mingw have their own
    target_ops->to_interrupt implementation, so it's fine to make
    child_interrupt be a nop.
    
    gdb/ChangeLog:
    2018-01-31  Pedro Alves  <palves@redhat.com>
    
    	* darwin-nat.c (darwin_interrupt): Remove ptid_t parameter.
    	* inflow.c (child_terminal_save_inferior): Wrap reference to
    	tcgetpgrp in HAVE_TERMIOS_H.
    	(child_interrupt, child_pass_ctrlc): Wrap references to signal in
    	_WIN32.
    	* remote-sim.c (gdbsim_interrupt): Remove ptid_t parameter and
    	always iterate over all inferiors.
    	(gdbsim_cntrl_c): Adjust.
    	* windows-nat.c (windows_interrupt): Remove 'ptid_t' parameter.

The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=3045b47554503c6f154e446662204e295fc769a1

commit 3045b47554503c6f154e446662204e295fc769a1
Author: Pedro Alves <palves@redhat.com>
Date:   Wed Jan 31 13:50:34 2018 +0000

    gdb: Fix remote-sim/MinGW/Darwin builds
    
    (Add missing ChangeLog entry)
    
    The recent commit e671cd59 ("Per-inferior target_terminal state, fix
    PR gdb/13211, more") missed adjusting a few targets to the new
    target_ops->to_interrupt interface, breaking the build for those
    targets.  This fixes it.
    
    Note: remote-sim doesn't really support async execution, so I don't
    think gdbsim_interrupt is ever reached via target_interrupt.  (It is
    reached via gdbsim_cntrl_c though).
    
    The inflow.c changes are a bit ugly, but they're just doing what other
    parts of the file already do to handle the same missing functions.
    Targets that don't have 'kill', like mingw have their own
    target_ops->to_interrupt implementation, so it's fine to make
    child_interrupt be a nop.
    
    gdb/ChangeLog:
    2018-01-31  Pedro Alves  <palves@redhat.com>
    
    	* darwin-nat.c (darwin_interrupt): Remove ptid_t parameter.
    	* inflow.c (child_terminal_save_inferior): Wrap reference to
    	tcgetpgrp in HAVE_TERMIOS_H.
    	(child_interrupt, child_pass_ctrlc): Wrap references to signal in
    	_WIN32.
    	* remote-sim.c (gdbsim_interrupt): Remove ptid_t parameter and
    	always iterate over all inferiors.
    	(gdbsim_cntrl_c): Adjust.
    	* windows-nat.c (windows_interrupt): Remove 'ptid_t' parameter.

I think this was fixed a while ago.