From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Date: Wed, 03 Jul 2019 17:07:38 +0000 Subject: Re: [PATCH 8/9] usb: Add USB subsystem notifications [ver #5] Message-Id: <20190703170738.GA24672@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <156173690158.15137.3985163001079120218.stgit@warthog.procyon.org.uk> <156173698939.15137.11150923486478934112.stgit@warthog.procyon.org.uk> In-Reply-To: <156173698939.15137.11150923486478934112.stgit@warthog.procyon.org.uk> To: David Howells Cc: viro@zeniv.linux.org.uk, Casey Schaufler , Stephen Smalley , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org On Fri, Jun 28, 2019 at 04:49:49PM +0100, David Howells wrote: > Add a USB subsystem notification mechanism whereby notifications about > hardware events such as device connection, disconnection, reset and I/O > errors, can be reported to a monitoring process asynchronously. > > Firstly, an event queue needs to be created: > > fd = open("/dev/event_queue", O_RDWR); > ioctl(fd, IOC_WATCH_QUEUE_SET_SIZE, page_size << n); > > then a notification can be set up to report USB notifications via that > queue: > > struct watch_notification_filter filter = { > .nr_filters = 1, > .filters = { > [0] = { > .type = WATCH_TYPE_USB_NOTIFY, > .subtype_filter[0] = UINT_MAX; > }, > }, > }; > ioctl(fd, IOC_WATCH_QUEUE_SET_FILTER, &filter); > notify_devices(fd, 12); > > After that, records will be placed into the queue when events occur on a > USB device or bus. Records are of the following format: > > struct usb_notification { > struct watch_notification watch; > __u32 error; > __u32 reserved; > __u8 name_len; > __u8 name[0]; > } *n; > > Where: > > n->watch.type will be WATCH_TYPE_USB_NOTIFY > > n->watch.subtype will be the type of notification, such as > NOTIFY_USB_DEVICE_ADD. > > n->watch.info & WATCH_INFO_LENGTH will indicate the length of the > record. > > n->watch.info & WATCH_INFO_ID will be the second argument to > device_notify(), shifted. > > n->error and n->reserved are intended to convey information such as > error codes, but are currently not used > > n->name_len and n->name convey the USB device name as an > unterminated string. This may be truncated - it is currently > limited to a maximum 63 chars. > > Note that it is permissible for event records to be of variable length - > or, at least, the length may be dependent on the subtype. > > Signed-off-by: David Howells > cc: Greg Kroah-Hartman > cc: linux-usb@vger.kernel.org Reviewed-by: Greg Kroah-Hartman From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH 8/9] usb: Add USB subsystem notifications [ver #5] Date: Wed, 3 Jul 2019 19:07:38 +0200 Message-ID: <20190703170738.GA24672@kroah.com> References: <156173690158.15137.3985163001079120218.stgit@warthog.procyon.org.uk> <156173698939.15137.11150923486478934112.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <156173698939.15137.11150923486478934112.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: David Howells Cc: viro@zeniv.linux.org.uk, Casey Schaufler , Stephen Smalley , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-api@vger.kernel.org On Fri, Jun 28, 2019 at 04:49:49PM +0100, David Howells wrote: > Add a USB subsystem notification mechanism whereby notifications about > hardware events such as device connection, disconnection, reset and I/O > errors, can be reported to a monitoring process asynchronously. > > Firstly, an event queue needs to be created: > > fd = open("/dev/event_queue", O_RDWR); > ioctl(fd, IOC_WATCH_QUEUE_SET_SIZE, page_size << n); > > then a notification can be set up to report USB notifications via that > queue: > > struct watch_notification_filter filter = { > .nr_filters = 1, > .filters = { > [0] = { > .type = WATCH_TYPE_USB_NOTIFY, > .subtype_filter[0] = UINT_MAX; > }, > }, > }; > ioctl(fd, IOC_WATCH_QUEUE_SET_FILTER, &filter); > notify_devices(fd, 12); > > After that, records will be placed into the queue when events occur on a > USB device or bus. Records are of the following format: > > struct usb_notification { > struct watch_notification watch; > __u32 error; > __u32 reserved; > __u8 name_len; > __u8 name[0]; > } *n; > > Where: > > n->watch.type will be WATCH_TYPE_USB_NOTIFY > > n->watch.subtype will be the type of notification, such as > NOTIFY_USB_DEVICE_ADD. > > n->watch.info & WATCH_INFO_LENGTH will indicate the length of the > record. > > n->watch.info & WATCH_INFO_ID will be the second argument to > device_notify(), shifted. > > n->error and n->reserved are intended to convey information such as > error codes, but are currently not used > > n->name_len and n->name convey the USB device name as an > unterminated string. This may be truncated - it is currently > limited to a maximum 63 chars. > > Note that it is permissible for event records to be of variable length - > or, at least, the length may be dependent on the subtype. > > Signed-off-by: David Howells > cc: Greg Kroah-Hartman > cc: linux-usb@vger.kernel.org Reviewed-by: Greg Kroah-Hartman