[PATCH v3 4/5] lib: membuff: fix readline not returning line in case of overflow

[Simon Glass]

Hi Svyatoslav,

On Tue, 21 Nov 2023 at 11:35, Svyatoslav Ryhel <clamor95 at gmail.com> wrote:
>
> From: Ion Agorria <ion at agorria.com>
>
> If line overflows readline it will not be returned, fix this behavior,
> make it optional and documented properly.
>
> Signed-off-by: Ion Agorria <ion at agorria.com>
> Signed-off-by: Svyatoslav Ryhel <clamor95 at gmail.com>
> Reviewed-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> ---
>  boot/bootmeth_extlinux.c | 2 +-
>  common/console.c         | 2 +-
>  include/membuff.h        | 5 +++--
>  lib/membuff.c            | 4 ++--
>  4 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/boot/bootmeth_extlinux.c b/boot/bootmeth_extlinux.c
> index aa2a4591eb..ae0ad1d53e 100644
> --- a/boot/bootmeth_extlinux.c
> +++ b/boot/bootmeth_extlinux.c
> @@ -82,7 +82,7 @@ static int extlinux_fill_info(struct bootflow *bflow)
>         log_debug("parsing bflow file size %x\n", bflow->size);
>         membuff_init(&mb, bflow->buf, bflow->size);
>         membuff_putraw(&mb, bflow->size, true, &data);
> -       while (len = membuff_readline(&mb, line, sizeof(line) - 1, ' '), len) {
> +       while (len = membuff_readline(&mb, line, sizeof(line) - 1, ' ', true), len) {
>                 char *tok, *p = line;
>
>                 tok = strsep(&p, " ");
> diff --git a/common/console.c b/common/console.c
> index 8a869b137e..cd56035171 100644
> --- a/common/console.c
> +++ b/common/console.c
> @@ -846,7 +846,7 @@ bool console_record_overflow(void)
>  int console_record_readline(char *str, int maxlen)
>  {
>         return membuff_readline((struct membuff *)&gd->console_out, str,
> -                               maxlen, '\0');
> +                               maxlen, '\0', false);
>  }
>
>  int console_record_avail(void)
> diff --git a/include/membuff.h b/include/membuff.h
> index 21051b0c54..4eba626ce1 100644
> --- a/include/membuff.h
> +++ b/include/membuff.h
> @@ -192,10 +192,11 @@ int membuff_free(struct membuff *mb);
>   * @mb: membuff to adjust
>   * @str: Place to put the line
>   * @maxlen: Maximum line length (excluding terminator)
> + * @must_fit: If true then str is empty if line doesn't fit
>   * Return: number of bytes read (including terminator) if a line has been
> - *        read, 0 if nothing was there
> + *        read, 0 if nothing was there or line didn't fit when must_fit is set
>   */
> -int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch);
> +int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch, bool must_fit);
>
>  /**
>   * membuff_extend_by() - expand a membuff
> diff --git a/lib/membuff.c b/lib/membuff.c
> index 36dc43a523..964e504d5b 100644
> --- a/lib/membuff.c
> +++ b/lib/membuff.c
> @@ -288,7 +288,7 @@ int membuff_free(struct membuff *mb)
>                         (mb->end - mb->start) - 1 - membuff_avail(mb);
>  }
>
> -int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch)
> +int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch, bool must_fit)

Shouldn't that be the normal case? I might have this wrong, but this
looks like a bug fix to me.
>  {
>         int len;  /* number of bytes read (!= string length) */
>         char *s, *end;
> @@ -310,7 +310,7 @@ int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch)
>         }
>
>         /* couldn't get the whole string */
> -       if (!ok) {
> +       if (!ok && must_fit) {
>                 if (maxlen)
>                         *orig = '\0';
>                 return 0;
> --
> 2.40.1
>