Commit 56c594d8 authored by Pierre-Eric Pelloux-Prayer's avatar Pierre-Eric Pelloux-Prayer Committed by Christian König
Browse files

drm: add DRM_SET_CLIENT_NAME ioctl 

Giving the opportunity to userspace to associate a free-form
name with a drm_file struct is helpful for tracking and debugging.

This is similar to the existing DMA_BUF_SET_NAME ioctl.

Access to client_name is protected by a mutex, and the 'clients' debugfs
file has been updated to print it.

Userspace MR to use this ioctl:
   https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1428



If the string passed by userspace contains chars that would mess up output
when it's going to be printed (in dmesg, fdinfo, etc), -EINVAL is returned.

A 0-length string is a valid use, and clears the existing name.

Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarPierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003124506.470931-2-pierre-eric.pelloux-prayer@amd.com


Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
parent 82fe69e6

drivers/gpu/drm/drm_debugfs.c

+10 −4
Original line number Diff line number Diff line
@@ -78,12 +78,14 @@ static int drm_clients_info(struct seq_file *m, void *data) 
	kuid_t uid;



	seq_printf(m,

		   "%20s %5s %3s master a %5s %10s\n",

		   "%20s %5s %3s master a %5s %10s %*s\n",

		   "command",

		   "tgid",

		   "dev",

		   "uid",

		   "magic");

		   "magic",

		   DRM_CLIENT_NAME_MAX_LEN,

		   "name");



	/* dev->filelist is sorted youngest first, but we want to present

	 * oldest first (i.e. kernel, servers, clients), so walk backwardss.
@@ -94,19 +96,23 @@ static int drm_clients_info(struct seq_file *m, void *data) 
		struct task_struct *task;

		struct pid *pid;



		mutex_lock(&priv->client_name_lock);

		rcu_read_lock(); /* Locks priv->pid and pid_task()->comm! */

		pid = rcu_dereference(priv->pid);

		task = pid_task(pid, PIDTYPE_TGID);

		uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID;

		seq_printf(m, "%20s %5d %3d   %c    %c %5d %10u\n",

		seq_printf(m, "%20s %5d %3d   %c    %c %5d %10u %*s\n",

			   task ? task->comm : "<unknown>",

			   pid_vnr(pid),

			   priv->minor->index,

			   is_current_master ? 'y' : 'n',

			   priv->authenticated ? 'y' : 'n',

			   from_kuid_munged(seq_user_ns(m), uid),

			   priv->magic);

			   priv->magic,

			   DRM_CLIENT_NAME_MAX_LEN,

			   priv->client_name ? priv->client_name : "<unset>");

		rcu_read_unlock();

		mutex_unlock(&priv->client_name_lock);

	}

	mutex_unlock(&dev->filelist_mutex);

	return 0;

drivers/gpu/drm/drm_file.c

+5 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor) 


	spin_lock_init(&file->master_lookup_lock);

	mutex_init(&file->event_read_lock);

	mutex_init(&file->client_name_lock);



	if (drm_core_check_feature(dev, DRIVER_GEM))

		drm_gem_open(dev, file);
@@ -258,6 +259,10 @@ void drm_file_free(struct drm_file *file) 
	WARN_ON(!list_empty(&file->event_list));



	put_pid(rcu_access_pointer(file->pid));



	mutex_destroy(&file->client_name_lock);

	kfree(file->client_name);



	kfree(file);

}

drivers/gpu/drm/drm_ioctl.c

+51 −0
Original line number Diff line number Diff line
@@ -540,6 +540,55 @@ int drm_version(struct drm_device *dev, void *data, 
	return err;

}



/*

 * Check if the passed string contains control char or spaces or

 * anything that would mess up a formatted output.

 */

static int drm_validate_value_string(const char *value, size_t len)

{

	int i;



	for (i = 0; i < len; i++) {

		if (!isascii(value[i]) || !isgraph(value[i]))

			return -EINVAL;

	}

	return 0;

}



static int drm_set_client_name(struct drm_device *dev, void *data,

			       struct drm_file *file_priv)

{

	struct drm_set_client_name *name = data;

	size_t len = name->name_len;

	void __user *user_ptr;

	char *new_name;



	if (len > DRM_CLIENT_NAME_MAX_LEN) {

		return -EINVAL;

	} else if (len) {

		user_ptr = u64_to_user_ptr(name->name);



		new_name = memdup_user_nul(user_ptr, len);

		if (IS_ERR(new_name))

			return PTR_ERR(new_name);



		if (strlen(new_name) != len ||

		    drm_validate_value_string(new_name, len) < 0) {

			kfree(new_name);

			return -EINVAL;

		}

	} else {

		new_name = NULL;

	}



	mutex_lock(&file_priv->client_name_lock);

	kfree(file_priv->client_name);

	file_priv->client_name = new_name;

	mutex_unlock(&file_priv->client_name_lock);



	return 0;

}



static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)

{

	/* ROOT_ONLY is only for CAP_SYS_ADMIN */
@@ -610,6 +659,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = { 
	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_RENDER_ALLOW),

	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_RENDER_ALLOW),



	DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_NAME, drm_set_client_name, DRM_RENDER_ALLOW),



	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, 0),

	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, 0),

	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER),

include/drm/drm_file.h

+9 −0
Original line number Diff line number Diff line
@@ -388,6 +388,15 @@ struct drm_file { 
	 * Per-file buffer caches used by the PRIME buffer sharing code.

	 */

	struct drm_prime_file_private prime;



	/**

	 * @client_name:

	 *

	 * Userspace-provided name; useful for accounting and debugging.

	 */

	const char *client_name;

	/** @name_lock: Protects @client_name. */

	struct mutex client_name_lock;

};



/**

include/uapi/drm/drm.h

+17 −0
Original line number Diff line number Diff line
@@ -1024,6 +1024,13 @@ struct drm_crtc_queue_sequence { 
	__u64 user_data;	/* user data passed to event */

};



#define DRM_CLIENT_NAME_MAX_LEN		64

struct drm_set_client_name {

	__u64 name_len;

	__u64 name;

};





#if defined(__cplusplus)

}

#endif
@@ -1288,6 +1295,16 @@ extern "C" { 
 */

#define DRM_IOCTL_MODE_CLOSEFB		DRM_IOWR(0xD0, struct drm_mode_closefb)



/**

 * DRM_IOCTL_SET_CLIENT_NAME - Attach a name to a drm_file

 *

 * Having a name allows for easier tracking and debugging.

 * The length of the name (without null ending char) must be

 * <= DRM_CLIENT_NAME_MAX_LEN.

 * The call will fail if the name contains whitespaces or non-printable chars.

 */

#define DRM_IOCTL_SET_CLIENT_NAME	DRM_IOWR(0xD1, struct drm_set_client_name)



/*

 * Device specific ioctls should only be in their respective headers

 * The device specific ioctl range is from 0x40 to 0x9f.