[Bug cli/21218] Regression: GDB dumps core when escaping newline in multi line command

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=21218

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6e5d74e74756fafe59e8198c4cc462cf7c57e12c

commit 6e5d74e74756fafe59e8198c4cc462cf7c57e12c
Author: Pedro Alves <palves@redhat.com>
Date:   Wed Mar 8 11:41:35 2017 +0000

    Fix PR 21218: GDB dumps core when escaping newline in multi-line command

    With commit 3b12939dfc2399 ("Replace the sync_execution global with a
    new enum prompt_state tristate"), GDB started aborting if you try
    splitting an input line with a continuation char (backslash) while in
    a multi-line command:

     (gdb) commands
     Type commands for breakpoint(s) 1, one per line.
     End with a line saying just "end".
     >print \

     (gdb) 1      # note "(gdb)" incorrectly printed here.
     >end

     readline: readline_callback_read_char() called with no handler!
     $

    That abort is actually a symptom of an old problem introduced when
    gdb_readline_wrapper was rewritten to use asynchronous readline, back
    in 2007.  Note how the "(gdb)" prompt is printed above in the "(gdb)
    1" line.  Clearly it shouldn't be there, but it already was before the
    commit mentioned above.  Fixing that also fixes the readline abort
    shown above.

    The problem starts when command_line_input passes a NULL prompt to
    gdb_readline_wrapper when it finds previous incomplete input due to a
    backslash, trying to fetch more input without printing another ">"
    secondary prompt.  That itself should not be a problem, because
    passing NULL to gdb_readline_wrapper has the same meaning as passing a
    pointer to empty string, since gdb_readline_wrapper exposes the same
    interface as 'readline(char *)'.  However, gdb_readline_wrapper passes
    the prompt argument directly to display_gdb_prompt, and for the
    latter, a NULL prompt argument has a different meaning - it requests
    printing the primary prompt.

    Before commit 782a7b8ef9c096 (which rewrote gdb_readline_wrapper to
    use asynchronous readline), GDB behaved like this:

     (gdb) commands
     [....]
     >print \
     1
     >end
     (gdb)

    The above is what this commit restores GDB back to.

    New test included.

    gdb/ChangeLog:
    2017-03-08  Pedro Alves  <palves@redhat.com>

        PR cli/21218
        * top.c (gdb_readline_wrapper): Avoid passing NULL to
        display_gdb_prompt.
        (command_line_input): Add comment.

    gdb/testsuite/ChangeLog:
    2017-03-08  Pedro Alves  <palves@redhat.com>
            Jan Kratochvil  <jan.kratochvil@redhat.com>

        PR cli/21218
        * gdb.base/commands.exp (backslash_in_multi_line_command_test):
        New proc.
        (top level): Call it.

-- 
You are receiving this mail because:
You are on the CC list for the bug.