What does the rmmount command do?

rmmount is a removable media mounter that is executed by Volume Management whenever a CD-ROM or floppy is inserted. The Volume Management daemon, vold, manages CD-ROM and floppy devices. Example: /usr/sbin/rmmount [ -D ].

Upon insertion, rmmount determines what type of file system (if any) is on the media. If a file system is present, rmmount mounts the file system in one of the following locations:

Mount Location			State of Media

/floppy/floppy0			symbolic link to mounted floppy in local floppy drive
/floppy/floppy_name		mounted named floppy
/floppy/unnamed_floppy		mounted unnamed floppy
/cdrom/cdrom0			symbolic link to mounted CD-ROM in local CD-ROM drive
/cdrom/CD-ROM_name		mounted named CD-ROM 
/cdrom/CD-ROM_name/partition	mounted named CD-ROM with partitioned file system
/cdrom/unnamed_cdrom		mounted unnamed CD-ROM

If the media is read-only (either CD-ROM or floppy with write-protect tab set), the file system is mounted read-only.

If a file system is not identified, rmmount does not mount a file system. See the System Administration Guide for more information on the location of CD-ROM and floppy media without file system. See volfs(7FS).

If a file system type has been determined, it is then checked to see that it is "clean". If the file system is "dirty", fsck -p (see fsck(1M)) is run in an attempt to clean it. If fsck fails, the file system is mounted read-only.

After the mount is complete, "actions" associated with the media type are executed. These actions allow for the notification to other programs that new media are available. These actions are shared objects and are described in the configuration file, /etc/rmmount.conf.

Actions are executed in the order in which they appear in the configuration file. The action function can return either 1 or 0. If it returns 0, no further actions will be executed. This allows the function to control which applications are executed.

In order to execute an action, rmmount performs a dlopen(3X) on the shared object and calls the action function defined within it. The definition of the interface to actions can be found in /usr/include/rmmount.h.

File systems mounted by rmmount are always mounted with the nosuid flag set, thereby disabling set-uid programs and access to block or character devices in that file system. Upon ejection, rmmount unmounts mounted file systems and executes actions associated with the media type. If a file system is "busy" (i.e., it contains the current working directory of a live process), the ejection will fail.