Re: [PATCH i-g-t 03/12] lib/igt_drm_fdinfo: Fix wrong name len assert

[Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>]

On Fri, Apr 05, 2024 at 01:00:47AM -0500, Lucas De Marchi wrote:
>When parsing engine name, at this point we have something like:
>
>	"drm-engine-render:	232409619162 ns"
>	            ^      ^
>	            |      |
>	          name     p
>
>We are copying the engine name to the final destination, but
>strlen(name) will actually contain the entire string. Since we already
>know the name length, calculated previously, just use it for copying the
>string.
>
>Since each name is 256-bytes long, the assert doesn't trigger easily,
>but it's better to be correct. And more efficient.

Agree,
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

>
>Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>---
> lib/igt_drm_fdinfo.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
>diff --git a/lib/igt_drm_fdinfo.c b/lib/igt_drm_fdinfo.c
>index 7a9ae94f0..9b1776775 100644
>--- a/lib/igt_drm_fdinfo.c
>+++ b/lib/igt_drm_fdinfo.c
>@@ -96,8 +96,9 @@ static int parse_engine(const char *name, struct drm_client_fdinfo *info,
>
> 		if (found < 0) {
> 			assert((info->num_engines + 1) < ARRAY_SIZE(info->names));
>-			assert((strlen(name) + 1) < sizeof(info->names[0]));
>-			strncpy(info->names[info->num_engines], name, name_len);
>+			assert(name_len  < sizeof(info->names[0]));
>+			memcpy(info->names[info->num_engines], name, name_len);
>+			info->names[info->num_engines][name_len] = '\0';
> 			found = info->num_engines;
> 		}
> 	}
>-- 
>2.44.0
>