[PATCH] common/command.c: Avoid NULL pointer use in cmd_auto_complete

[Simon Glass]

Hi Adam,

On 2026-05-14T14:06:41, Adam Lackorzynski <adam at l4re.org> wrote:
> common/command.c: Avoid NULL pointer use in cmd_auto_complete
>
> Avoid putting a potential NULL pointer to strcmp, which would lead to a
> load at address 0.
>
> Signed-off-by: Adam Lackorzynski <adam at l4re.org>
>
> common/command.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

> diff --git a/common/command.c b/common/command.c
> @@ -373,7 +373,7 @@ int cmd_auto_complete(const char *const prompt, char *buf, int *np, int *colp)
>       const char *ps_prompt = CONFIG_SYS_PROMPT;
>  #endif
>
> -     if (strcmp(prompt, ps_prompt) != 0)
> +     if (ps_prompt && strcmp(prompt, ps_prompt) != 0)
>               return 0;       /* not in normal console */

This avoids the deref but isn't quite right. uboot_cli_readline() in
common/cli_hush.c falls back to CONFIG_SYS_PROMPT (or
CONFIG_SYS_PROMPT_HUSH_PS2 for promptmode 2) when PS1 is unset, so
prompt here is never NULL. With your change, a NULL PS1 makes the
comparison succeed unconditionally and promptmode 2 gets treated as
the normal console.

Please can you fall back to the default when env_get() returns NULL,
mirroring the readline path:

    const char *ps_prompt;

    if (IS_ENABLED(CONFIG_CMDLINE_PS_SUPPORT)) {
        ps_prompt = env_get('PS1');

        if (!ps_prompt)
                ps_prompt = CONFIG_SYS_PROMPT;
    } else {
        ps_prompt = CONFIG_SYS_PROMPT;
    }

What do you think?

Regards,
Simon