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Pedro Alves d9de1fe3d5 Fix PR20494 - User input stops being echoed in CLI
This patch fixes a problem that problem triggers if you start an
inferior, e.g., with the "start" command, in a UI created with the
new-ui command, and then run a foreground execution command in the
main UI.  Once the program stops for the latter command, typing in the
main UI no longer echoes back to the user.

The problem revolves around this:

- gdb_has_a_terminal computes its result lazily, on first call.

  that is what saves gdb's initial main UI terminal state (the UI
  associated with stdin):

          our_terminal_info.ttystate = serial_get_tty_state (stdin_serial);

  This is the state that target_terminal_ours() restores.

- In this scenario, the gdb_has_a_terminal function happens to be
  first ever called from within the target_terminal_init call in
  startup_inferior:

      (top-gdb) bt
      #0  gdb_has_a_terminal () at src/gdb/inflow.c:157
      #1  0x000000000079db22 in child_terminal_init_with_pgrp () at src/gdb/inflow.c:217
       [...]
      #4  0x000000000065bacb in target_terminal_init () at src/gdb/target.c:456
      #5  0x00000000004676d2 in startup_inferior () at src/gdb/fork-child.c:531
       [...]
      #7  0x000000000046b168 in linux_nat_create_inferior () at src/gdb/linux-nat.c:1112
       [...]
      #9  0x00000000005f20c9 in start_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:657

If the command to start the inferior is issued on the main UI, then
readline will have deprepped the terminal when we reach the above, and
the problem doesn't appear.

If however the command is issued on a non-main UI, then when we reach
that gdb_has_a_terminal call, the main UI's terminal state is still
set to whatever readline has sets it to in rl_prep_terminal, which
happens to have echo disabled.  Later, when the following synchronous
execution command finishes, we'll call target_terminal_ours to restore
gdb's the main UI's terminal settings, and that restores the terminal
state with echo disabled...

Conceptually, the fix is to move the gdb_has_a_terminal call earlier,
to someplace during GDB initialization, before readline/ncurses have
had a chance to change terminal settings.  Turns out that
"set_initial_gdb_ttystate" is exactly such a place.

I say conceptually, because the fix actually inlines the
gdb_has_a_terminal part that saves the terminal state in
set_initial_gdb_ttystate and then simplifies gdb_has_a_terminal, since
there's no point in making gdb_has_a_terminal do lazy computation.

gdb/ChangeLog:
2016-08-23  Pedro Alves  <palves@redhat.com>

	PR gdb/20494
	* inflow.c (our_terminal_info, initial_gdb_ttystate): Update
	comments.
	(enum gdb_has_a_terminal_flag_enum, gdb_has_a_terminal_flag):
	Delete.
	(set_initial_gdb_ttystate): Record our_terminal_info here too,
	instead of ...
	(gdb_has_a_terminal): ... here.  Reimplement in terms of
	initial_gdb_ttystate.  Make static.
	* terminal.h (gdb_has_a_terminal): Delete declaration.
	(set_initial_gdb_ttystate): Add comment.
	* top.c (show_interactive_mode): Use input_interactive_p instead
	of gdb_has_a_terminal.

gdb/testsuite/ChangeLog:
2016-08-23  Pedro Alves  <palves@redhat.com>

	PR gdb/20494
	* gdb.base/new-ui-echo.c: New file.
	* gdb.base/new-ui-echo.exp: New file.
2016-08-23 16:03:28 +01:00
bfd Fix seg-fault in ARM linker when trying to parse a binary file. 2016-08-23 09:46:36 +01:00
binutils Place .shstrtab section after .symtab and .strtab, thus restoring monotonically increasing section offsets. 2016-08-19 09:16:30 +01:00
config
cpu
elfcpp
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gas ARM: Issue a warning when the MRRC and MRRC2 instructions are used with the same destination registers. 2016-08-19 12:58:49 +01:00
gdb Fix PR20494 - User input stops being echoed in CLI 2016-08-23 16:03:28 +01:00
gold Fix extraneous complaints about missing expected TLS relocation (i386). 2016-08-17 10:53:31 -07:00
gprof Better fix for PR 20499, including preventing strlen from being called on an uninitialised name field. 2016-08-23 15:41:01 +01:00
include 2016-08-04 Thomas Preud'homme <thomas.preudhomme@arm.com> 2016-08-04 15:36:52 +01:00
intl
ld Fix duplicate FAILs from ld testsuite 2016-08-23 12:23:05 +09:30
libdecnumber
libiberty Synchronize libiberty sources with FSF GCC mainline version. 2016-08-02 13:26:28 +01:00
opcodes [AArch64] Add V8_2_INSN macro 2016-08-23 09:03:19 +01:00
readline
sim sim: m68hc11: use standard STATIC_INLINE helper 2016-08-16 06:12:39 -07:00
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ChangeLog Enable the configuration of GDB for the NDS32 target. 2016-07-20 09:06:39 +01:00
compile
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configure Enable the configuration of GDB for the NDS32 target. 2016-07-20 09:06:39 +01:00
configure.ac Enable the configuration of GDB for the NDS32 target. 2016-07-20 09:06:39 +01:00
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