Re: [Crash-utility] [PATCH] Output prompt when stdin is not a TTY.

On Wed, May 31, 2023 at 11:05 AM Hsin-Yi Wang <hsinyi(a)chromium.org&gt; wrote: > > On Wed, May 31, 2023 at 10:54 AM HAGIO KAZUHITO(萩尾　一仁) > <k-hagio-ab(a)nec.com&gt; 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(a)chromium.org&gt; > > > > 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); > > > }