[PATCH 2/4] drm: Add dispatcher and driver identification for DRM

[Dmitry V. Levin]

On Tue, Jun 09, 2015 at 01:26:42PM +0200, Patrik Jakobsson wrote:
[...]
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -121,6 +121,7 @@ strace_SOURCES =	\
>  	utime.c		\
>  	utimes.c	\
>  	v4l2.c		\
> +	drm.c		\
>  	vsprintf.c	\
>  	wait.c		\
>  	xattr.c

Starting with v4.7-166-g7ae73a9, we keep strace_SOURCES list sorted.

> --- /dev/null
> +++ b/drm.c
[...]
> +#include "defs.h"
> +
> +#include <sys/types.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <linux/limits.h>
> +#include <stdint.h>
> +#include <sys/ioctl.h>
> +#include <linux/types.h>
> +#include <drm.h>

No need to include header files already included by "defs.h".
Most likely no need to include <linux/limits.h> or <linux/types.h>.

> +#define DRM_MAX_NAME_LEN 128
> +
> +inline int drm_is_priv(const unsigned int num)
> +{
> +	return (_IOC_NR(num) >= DRM_COMMAND_BASE &&
> +		_IOC_NR(num) < DRM_COMMAND_END);
> +}
> +
> +static int drm_get_driver_name(struct tcb *tcp, char *name, size_t bufsize)
> +{
> +	char path[PATH_MAX];
> +	char link[PATH_MAX];
> +	int ret;
> +
> +	ret = getfdpath(tcp, tcp->u_arg[0], path, PATH_MAX - 1);
> +	if (!ret)
> +		return ret;
> +
> +	snprintf(link, PATH_MAX, "/sys/class/drm/%s/device/driver",
> +		 basename(path));
> +
> +	ret = readlink(link, path, PATH_MAX - 1);
> +	if (ret < 0)
> +		return ret;
> +
> +	path[ret] = '\0';
> +	strncpy(name, basename(path), bufsize);
> +
> +	return 0;
> +}
> +
> +int drm_is_driver(struct tcb *tcp, const char *name)
> +{
> +	char drv[DRM_MAX_NAME_LEN];
> +	int ret;
> +
> +	ret = drm_get_driver_name(tcp, drv, DRM_MAX_NAME_LEN);
> +	if (ret)
> +		return 0;
> +
> +	return strcmp(name, drv) == 0;
> +}

This interface will result to several getfdpath() calls per
ioctl_decode().  If the only purpose of drm_is_driver() is to help finding
the most appropriate function, let's create a table of pairs
{driver name, function} and pass this table to a function that will do a
single getfdpath() call, calculate the driver name, and choose the right
function from the table.

[...]
> @@ -284,6 +294,7 @@ ioctl_decode(struct tcb *tcp, unsigned int code, long arg)
>   *   d	sys/des.h			(possible overlap)
>   *   d	vax/dkio.h			(possible overlap)
>   *   d	vaxuba/rxreg.h			(possible overlap)
> + *   d  drm/drm.h
>   *   f	sys/filio.h
>   *   g	sunwindow/win_ioctl.h		-no overlap-
>   *   g	sunwindowdev/winioctl.c		!no manifest constant! -no overlap-

This is a history, no need to patch it.


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