From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: libsndio: Increase the sioctl_desc->display string size
To: Alexandre Ratchov <alex@caoua.org>
Cc: tech@openbsd.org
Date: Mon, 15 Dec 2025 09:41:08 -0700

Are there any other library ABI cranks in the pipeline?

Alexandre Ratchov <alex@caoua.org> wrote:

> Now that the display string contains the product name usb audio
> interfaces, more than 12-bytes may be needed.
> 
> This requires a major library version bump. This is the opportunity to
> increase other strings and add padding for future uses. FWIW this
> change increases the sioctl_desc structure from 80B to 128B.
> 
> OK?
> 
> Index: include/sndio.h
> ===================================================================
> RCS file: /cvs/src/include/sndio.h,v
> diff -u -p -r1.15 sndio.h
> --- include/sndio.h	24 May 2024 15:10:26 -0000	1.15
> +++ include/sndio.h	15 Dec 2025 13:28:46 -0000
> @@ -27,17 +27,9 @@
>  
>  /*
>   * limits
> - *
> - * For now SIOCTL_DISPLAYMAX is 12 byte only. It nicely fits in the
> - * padding of the sioctl_desc structure: this allows any binary linked
> - * to the library version with no sioctl_desc->display to work with
> - * this library version. Currently, any string reported by the lower
> - * layers fits in the 12-byte buffer. Once larger strings start
> - * being used (or the ABI changes for any other reason) increase
> - * SIOCTL_DISPLAYMAX and properly pad the sioctl_desc structure.
>   */
> -#define SIOCTL_NAMEMAX		12	/* max name length */
> -#define SIOCTL_DISPLAYMAX	12	/* max display string length */
> +#define SIOCTL_NAMEMAX		16	/* max name length */
> +#define SIOCTL_DISPLAYMAX	32	/* max display string length */
>  
>  /*
>   * private ``handle'' structure
> @@ -119,11 +111,12 @@ struct sioctl_desc {
>  #define SIOCTL_LIST		5	/* switch, element of a list */
>  #define SIOCTL_SEL		6	/* element of a selector */
>  	unsigned int type;		/* one of above */
> +	unsigned int maxval;		/* max value */
> +	int __pad[3];			/* for future use */
>  	char func[SIOCTL_NAMEMAX];	/* function name, ex. "level" */
>  	char group[SIOCTL_NAMEMAX];	/* group this control belongs to */
>  	struct sioctl_node node0;	/* affected node */
>  	struct sioctl_node node1;	/* dito for SIOCTL_{VEC,LIST,SEL} */
> -	unsigned int maxval;		/* max value */
>  	char display[SIOCTL_DISPLAYMAX];	/* free-format hint */
>  };
>  
> Index: lib/libsndio/shlib_version
> ===================================================================
> RCS file: /cvs/src/lib/libsndio/shlib_version,v
> diff -u -p -r1.15 shlib_version
> --- lib/libsndio/shlib_version	16 Jul 2025 15:33:05 -0000	1.15
> +++ lib/libsndio/shlib_version	15 Dec 2025 13:28:46 -0000
> @@ -1,2 +1,2 @@
> -major=8
> +major=9
>  minor=0
>