On Wed, May 31, 2023 at 11:05 AM Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> wrote:
>
> On Wed, May 31, 2023 at 10:54 AM HAGIO KAZUHITO(萩尾 一仁)
> <k-hagio-ab@xxxxxxx> wrote:
> >
> > On 2023/05/31 3:13, Hsin-Yi Wang wrote:
> > > When stdin is not a TTY, prompt ("crash> ") won't be displayed. If
> > > another process interact with crash with piped stdin/stdout, it will not
> > > get the prompt as a delimiter.
> > >
> > > Compared to other debugger like gdb, crash seems intended to give a
> > > prompt in this case in the beginning of process_command_line(). It
> > > checks if pc->flags does NOT have any of
> > > READLINE|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE, a
> > > prompt should be printed. The check will never be true since READLINE is
> > > set in setup_environment() unconditionally. It makes more sense to
> > > change the READLINE flag in the check to TTY instead.
> > >
> > > Additionally, when stdin is not TTY, repeat the command line from user
> > > after prompt, which can give more context.
> > >
> > > The prompt and command line can be opt out by using the silent (-s) flag.
> > >
> > > Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> >
> > Thanks, but I found a case that prints two prompts, after a fatal error:
> >
> > # cat ~/.crashrc
> > sys config <<-- any command that fails with error(FATAL)
> > sys
> > # echo quit | crash
> > ...
> > 2 crash> sys config
> > sys: kernel_config_data does not exist in this kernel
> > 1 crash> 2 crash> sys
> > KERNEL: /usr/lib/debug/lib/modules/4.18.0-305.el8.x86_64/vmlinux
> > ...
> >
> > where the crash has this:
> >
> > --- a/cmdline.c
> > +++ b/cmdline.c
> > @@ -66,7 +66,7 @@ process_command_line(void)
> >
> > if (!(pc->flags &
> > (TTY|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE)))
> > - fprintf(fp, "%s", pc->prompt);
> > + fprintf(fp, "1 %s", pc->prompt);
> > fflush(fp);
> >
> > /*
> > @@ -1487,7 +1487,7 @@ exec_input_file(void)
> > continue;
> >
> > if (!(pc->flags & SILENT)) {
> > - fprintf(fp, "%s%s", pc->prompt, buf);
> > + fprintf(fp, "2 %s%s", pc->prompt, buf);
Ah, I misread this as the fprintf in process_command_line. I'll take a
look at this issue to see how to avoid it. Sorry for the confusion.
>
> I don't think we need to print a prompt again here. It can be used as
> a delimiter when all the previous output are done and waiting for user
> input. If we print the prompt again. what it will read:
>
> crash 8.0.3++
> 1 crash>
> // suppose stdin has cmd1 after here.
> 2 crash> cmd1
> cmd1_output
> 1 crash>
> // supposes stdin has cmd2 after here.
> 2 crash> cmd2
> cmd2_output
>
> Without the 2nd prompt:
> crash 8.0.3++
> 1 crash>
> // suppose stdin has cmd1 after here.
> cmd1
> cmd1_output
> 1 crash>
> // suppose stdin has cmd2 after here.
> cmd2
> cmd2_output
>
> > fflush(fp);
> > }
> >
> > Can we avoid this?
> >
> > Thanks,
> > Kazu
> >
> > > ---
> > > v1:
> > > - The original discussion: https://listman.redhat.com/archives/crash-utility/2023-May/010710.html
> > > - Kazu: provide the idea to print the command line as well.
> > > ---
> > > cmdline.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/cmdline.c b/cmdline.c
> > > index ded6551..9821d86 100644
> > > --- a/cmdline.c
> > > +++ b/cmdline.c
> > > @@ -65,7 +65,7 @@ process_command_line(void)
> > > BZERO(pc->command_line, BUFSIZE);
> > >
> > > if (!(pc->flags &
> > > - (READLINE|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE)))
> > > + (TTY|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE)))
> > > fprintf(fp, "%s", pc->prompt);
> > > fflush(fp);
> > >
> > > @@ -139,6 +139,10 @@ process_command_line(void)
> > > } else {
> > > if (fgets(pc->command_line, BUFSIZE-1, stdin) == NULL)
> > > clean_exit(1);
> > > + if (!(pc->flags & SILENT)) {
> > > + fprintf(fp, "%s", pc->command_line);
> > > + fflush(fp);
> > > + }
> > > clean_line(pc->command_line);
> > > strcpy(pc->orig_line, pc->command_line);
> > > }
--
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