Re: [Crash-utility] [PATCH v2] Output prompt when stdin is not a TTY

Date: Wed, 31 May 2023 14:01:36 +0800 From: Hsin-Yi Wang <hsinyi(a)chromium.org&gt; To: crash-utility(a)redhat.com, k-hagio-ab(a)nec.com Subject: [Crash-utility] [PATCH v2] Output prompt when stdin is not a TTY. Message-ID: <20230531060349.711886-1-hsinyi(a)chromium.org&gt; Content-Type: text/plain; charset="US-ASCII"; x-default=true 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. Besides this change, the prompt in process_command_line() should only be print when it's not in the middle of processing the input file recovering from a previous FATAL command, because the prompt will be displayed by the exec_input_file(). 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; --- v1: https://listman.redhat.com/archives/crash-utility/2023-May/010740.html v1->v2: 1. remove additional prompt when recovering from FATAL command from file. 2. fix a few space/tab indent. --- cmdline.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/cmdline.c b/cmdline.c index ded6551..b7f919a 100644 --- a/cmdline.c +++ b/cmdline.c @@ -64,8 +64,8 @@ process_command_line(void) fp = stdout; BZERO(pc->command_line, BUFSIZE); - if (!(pc->flags & - (READLINE|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE))) + if (!pc->ifile_in_progress && !(pc->flags & + (TTY|SILENT|CMDLINE_IFILE|RCHOME_IFILE|RCLOCAL_IFILE))) fprintf(fp, "%s", pc->prompt); fflush(fp); @@ -136,12 +136,16 @@ process_command_line(void) add_history(pc->command_line); check_special_handling(pc->command_line); - } else { - if (fgets(pc->command_line, BUFSIZE-1, stdin) == NULL) + } 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); - } + } /* * First clean out all linefeeds and leading/trailing spaces. -- 2.41.0.rc0.172.g3f132b7071-goog