[PATCH] libbb: make '--help' handling more consistent

[Denys Vlasenko]

Applied, thank you

On Sun, May 1, 2022 at 10:46 AM Ron Yorston <rmy at pobox.com> wrote:
>
> Running an applet with '--help' as its only argument is treated
> as a special case.  If additional arguments follow '--help' the
> behaviour is inconsistent:
>
> - applets which call single_argv() print help and do nothing else;
>
> - applets which call getopt() report "unrecognized option '--help'"
>   and print help anyway;
>
> - expr says "expr: syntax error" and doesn't print help;
>
> - printenv silently ignores '--help', prints any other variables
>   and doesn't print help;
>
> - realpath says "--help: No such file or directory", prints the path
>   of any other files and doesn't print help.
>
> If the first argument is '--help' ignore any other arguments and print
> help.  This is more consistent and most likely what the user wanted.
>
> See also commit 6bdfbc4cb (libbb: fix '--help' handling in
> FEATURE_SH_NOFORK=y).
>
> function                                             old     new   delta
> show_usage_if_dash_dash_help                          75      69      -6
> ------------------------------------------------------------------------------
> (add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-6)               Total: -6 bytes
>
> Signed-off-by: Ron Yorston <rmy at pobox.com>
> ---
>  libbb/appletlib.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/libbb/appletlib.c b/libbb/appletlib.c
> index 841b3b873..d56b5b409 100644
> --- a/libbb/appletlib.c
> +++ b/libbb/appletlib.c
> @@ -258,7 +258,6 @@ void lbb_prepare(const char *applet
>         /* Redundant for busybox (run_applet_and_exit covers that case)
>          * but needed for "individual applet" mode */
>         if (argv[1]
> -        && !argv[2]
>          && strcmp(argv[1], "--help") == 0
>          && !is_prefixed_with(applet, "busybox")
>         ) {
> @@ -940,8 +939,8 @@ void FAST_FUNC show_usage_if_dash_dash_help(int applet_no, char **argv)
>          && applet_no != APPLET_NO_echo
>  #  endif
>         ) {
> -               if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
> -                       /* Make "foo --help" exit with 0: */
> +               if (argv[1] && strcmp(argv[1], "--help") == 0) {
> +                       /* Make "foo --help [...]" exit with 0: */
>                         xfunc_error_retval = 0;
>                         bb_show_usage();
>                 }
> --
> 2.35.1
>
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