Re: [PATCH 2/2] help.c: use SHELL_PATH instead of hard-coded "/bin/sh"

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 8, 2015, 07:52 UTC
Message-ID: <xmqq61acsz7k.fsf@gitster.dls.corp.google.com>
In-Reply-To: <0ebc0373b21c75fa88adb5aefd098e9@74d39fa044aa309eaea14b9f57fe79c>

"Kyle J. McKay" <mackyle@gmail.com> writes:

Show 18 quoted lines

> If the user has set SHELL_PATH in the Makefile then we
> should respect that value and use it.
>
> Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
> ---
>  builtin/help.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/builtin/help.c b/builtin/help.c
> index 6133fe49..2ae8a1e9 100644
> --- a/builtin/help.c
> +++ b/builtin/help.c
> @@ -171,7 +171,7 @@ static void exec_man_cmd(const char *cmd, const char *page)
>  {
>  	struct strbuf shell_cmd = STRBUF_INIT;
>  	strbuf_addf(&shell_cmd, "%s %s", cmd, page);
> -	execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
> +	execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);

It is a common convention to make the first argument the command name without its path, and this change breaks that convention.

Does it matter, or would it break something? I recall that some implementations of shell (e.g. "bash") change their behaviour depending on how they are invoked (e.g. "ln -s bash /bin/sh" makes it run in posix mode) but I do not know if they do so by paying attention to their argv[0]. There might be other fallouts I do not think of offhand here.

I do not have an objection to what these patches want to do, though.

Thanks.

>  	warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
>  }
>  
> ---