resmgrd - resource manager daemon

resmgrd [-f configfile] [-s socket] [-p pidfile] [-kd]

resmgrd is a resource manager that allows applications to access and lock device files. It supports hot-plugging, i.e. devices can be added to a resource class as they become available, and can be removed when unplugged.

Devices are grouped in so-called resource classes. Each device in a resource class has an associated flag that defines whether applications are permitted to open it for reading and writing, or for reading only. The devices in a resource class can be defined in the static configuration file, but they can also be added and removed dynamically by a hotplugging daemon.

For most purposes, having a single resource class will be enough, but you can have several if you want.

Access control to device files happens at the resource class level as well. Users can be granted the right to access devices from a certain resource class. Again, access control can be defined statically in the configuration file, or dynamically.

Applications communicate with resmgrd through an AF_LOCAL socket. When the client wants to access a device file, it asks the resource manager to do so. If permitted by the access control lists, the resource manager will open the device file and pass the open file descriptor back to the client via the AF_LOCAL socket.

Additionally, applications can use the resource manager to lock and unlock a device file. This happens via traditional UUCP-style lock files in /var/lock. The main purpose of this is to allow applications using serial devices to continue using UUCP-style locks.

All other operations, such as adding devices to a resource class, or granting a user access to a class, are restricted to the administrator.

resmgr.conf(5), resmgr(1).

Olaf Kirch <okir@lst.de>