Re: [PATCH v3 12/18] rtla: Enforce exact match for time unit suffixes

[Tomas Glozar]

čt 15. 1. 2026 v 18:28 odesílatel Wander Lairson Costa
<wander@xxxxxxxxxx> napsal:
>
> The parse_ns_duration() function currently uses prefix matching for
> detecting time units. This approach is problematic as it silently
> accepts malformed strings such as "100nsx" or "100us_invalid" by
> ignoring the trailing characters, leading to potential configuration
> errors.
>
> Switch to using strcmp() for suffix comparison to enforce exact matches.
> This ensures that the parser strictly validates the time unit and
> rejects any input containing invalid trailing characters, thereby
> improving the robustness of the configuration parsing.
>

Why not use your strncmp_static() helper to protect from overrun?

> Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
> ---
>  tools/tracing/rtla/src/utils.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c
> index 486d96e8290fb..b029fe5970c31 100644
> --- a/tools/tracing/rtla/src/utils.c
> +++ b/tools/tracing/rtla/src/utils.c
> @@ -211,15 +211,15 @@ long parse_ns_duration(char *val)
>         t = strtol(val, &end, 10);
>
>         if (end) {
> -               if (!strncmp(end, "ns", 2)) {
> +               if (strcmp(end, "ns") == 0) {
>                         return t;
> -               } else if (!strncmp(end, "us", 2)) {
> +               } else if (strcmp(end, "us") == 0) {
>                         t *= 1000;
>                         return t;
> -               } else if (!strncmp(end, "ms", 2)) {
> +               } else if (strcmp(end, "ms") == 0) {
>                         t *= 1000 * 1000;
>                         return t;
> -               } else if (!strncmp(end, "s", 1)) {
> +               } else if (strcmp(end, "s") == 0) {
>                         t *= 1000 * 1000 * 1000;
>                         return t;
>                 }
> --
> 2.52.0
>

Tomas