linux-kernel - Re: [PATCH] kdb: Remove optional size arguments from strscpy() calls

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Message-ID: <CAFhGd8rH1PcjjRyKzaC9CgvFgA4_uEwvsCq-4v98bmVbqi=o2A@mail.gmail.com>
Date: Wed, 19 Mar 2025 14:11:04 -0700
From: Justin Stitt <justinstitt@...gle.com>
To: Thorsten Blum <thorsten.blum@...ux.dev>
Cc: Jason Wessel <jason.wessel@...driver.com>, Daniel Thompson <danielt@...nel.org>, 
	Douglas Anderson <dianders@...omium.org>, Arnd Bergmann <arnd@...db.de>, 
	Daniel Thompson <daniel.thompson@...aro.org>, kgdb-bugreport@...ts.sourceforge.net, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kdb: Remove optional size arguments from strscpy() calls

On Wed, Mar 19, 2025 at 9:35 AM Thorsten Blum <thorsten.blum@...ux.dev> wrote:
>
> If the destination buffer has a fixed length, strscpy() automatically
> determines the size of the destination buffer using sizeof() if the
> argument is omitted. This makes the explicit sizeof() unnecessary.
>
> Furthermore, CMD_BUFLEN is equal to sizeof(kdb_prompt_str) and can also
> be removed. Remove them to shorten and simplify the code.
>
> No functional changes intended.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
> ---
>  kernel/debug/kdb/kdb_io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
> index 6a77f1c779c4..9b11b10b120c 100644
> --- a/kernel/debug/kdb/kdb_io.c
> +++ b/kernel/debug/kdb/kdb_io.c
> @@ -334,7 +334,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
>                 *cp = '\0';
>                 p_tmp = strrchr(buffer, ' ');
>                 p_tmp = (p_tmp ? p_tmp + 1 : buffer);
> -               strscpy(tmpbuffer, p_tmp, sizeof(tmpbuffer));
> +               strscpy(tmpbuffer, p_tmp);
>                 *cp = tmp;
>
>                 len = strlen(tmpbuffer);
> @@ -452,7 +452,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
>  char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
>  {
>         if (prompt && kdb_prompt_str != prompt)
> -               strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
> +               strscpy(kdb_prompt_str, prompt);
>         kdb_printf("%s", kdb_prompt_str);
>         kdb_nextline = 1;       /* Prompt and input resets line number */
>         return kdb_read(buffer, bufsize);

This matches the pattern of replacements I've done in the past, all looks good.

Reviewed-by: Justin Stitt <justinstitt@...gle.com>

Justin