[Bug gdb/17694] New: Terminal isn't properly restored after the change to rl_callback functions

[Bug gdb/17694] New: Terminal isn't properly restored after the change to rl_callback functions

[terry.guo at arm dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17694

            Bug ID: 17694
           Summary: Terminal isn't properly restored after the change to
                    rl_callback functions
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: critical
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: terry.guo at arm dot com

Hi there,

I am working on Ubuntu 12.04 64bit and using gdb trunk for arm-none-eabi
target. 

Before this change:

commit cbd6f6bf80881be4628622e369baafb337589578
Author: Pedro Alves <palves@redhat.com>
Date:   Thu Oct 23 17:13:35 2014 +0100

    PR python/17372 - Python hangs when displaying help()

    This is more of a readline/terminal issue than a Python one.

My command "arm-none-eabi-gdb -x gdb.cmd coremark.axf" works fine and I can get
back to a normal terminal. Now with above change, after the execution of same
command, the terminal is abnormal, I can't see what I typed, but I can see the
results of typed command. Looks to me the echo feature of terminal isn't
properly restored. I have to use shell 'reset' command to reset the terminal.

However everything works fine if I source my script gdb.cmd in gdb terminal
manually. 

This is an embedded project running on a small SOC board. I am sorry that I
can't provide a test case. But I compared how those gdb_rl_callback_handler_*
functions are called in above two different calling methods. Hope this can help
you to understand the issue. Please let me know if further information is
needed.

First thing: before above change, the readline rl_callback_handler* functions
are never called in my case. I just insert printf function into those functions
and never see the output. So I assume they are not called.

Now with above change, I insert three printf functions into new
gdb_rl_callback_handler_* functions. With command "arm-none-eabi-gdb -x gdb.cmd
coremark.axf", I got:

arm-none-eabi-gdb -x g.cmd  coremark.axf
GNU gdb (GDB) 7.8.1.20141210-cvs
<<snip it for the sake of simplicity>>
Semihosting disabled.
Breakpoint 1 at 0xa8
Note: automatically using hardware breakpoints for read-only addresses.

Breakpoint 1, 0x000000a8 in _start ()
------I am in gdb_rl_callback_handler_reinstall function and the condition is
true
------I am in gdb_rl_callback_handler_install function
Semihosting enabled.
Breakpoint 2 at 0x6258
<<snip it for the sake of simplicity>>
Correct operation validated. See readme.txt for run and reporting rules.

Breakpoint 2, 0x00006258 in _exit ()

Program received signal SIGQUIT, Quit.
0x0000626c in _kill ()

Now the command is finished and I am in terminal, but I can't see what I typed.

But if I manually source the gdb.cmd in gdb terminal, I got:

arm-none-eabi-gdb   coremark.axf
GNU gdb (GDB) 7.8.1.20141210-cvs
<<<snip it>>>
Reading symbols from coremark.axf...(no debugging symbols found)...done.
------I am in gdb_rl_callback_handler_remove function
------I am in gdb_rl_callback_handler_install function
(gdb) source g.cmd 
0x0000626c in _kill ()
Semihosting disabled.
Breakpoint 1 at 0xa8
Note: automatically using hardware breakpoints for read-only addresses.

Breakpoint 1, 0x000000a8 in _start ()
Semihosting enabled.
Breakpoint 2 at 0x6258
<<snip it>>
Breakpoint 2, 0x00006258 in _exit ()

Program received signal SIGQUIT, Quit.
0x0000626c in _kill ()

Now the command is finished and I am in terminal. Everything is fine.

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[Bug gdb/17694] Terminal isn't properly restored after the change to rl_callback functions

[terry.guo at arm dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17694

Terry Guo <terry.guo at arm dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |palves at redhat dot com

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