File Systems & Mount Control

Mount and Unmount File Systems

mount

Supported functionality in SCML:

// Create a new mount
mount(
    source, target, filesystemtype,
    mountflags = 0,
    data
);

// Move the existing mount point
mount(
    source, target, filesystemtype,
    mountflags = MS_MOVE,
    data
);

// Create a bind mount
mount(
    source, target, filesystemtype,
    mountflags = MS_BIND | MS_REC,
    data
);

Partially supported mount flags:

• MS_REC is only effective when used in conjunction with MS_BIND
• MS_REMOUNT can be used, but the set options have no actual effect.
• MS_DIRSYNC can be set but have no actual effect.
• MS_LAZYTIME can be set but have no actual effect.
• MS_MANDLOCK can be set but have no actual effect.
• MS_NOATIME can be set but have no actual effect.
• MS_NODEV can be set but have no actual effect.
• MS_NODIRATIME can be set but have no actual effect.
• MS_NOEXEC can be set but have no actual effect.
• MS_NOSUID can be set but have no actual effect.
• MS_RDONLY can be set but have no actual effect.
• MS_RELATIME can be set but have no actual effect.
• MS_SILENT can be set but have no actual effect.
• MS_STRICTATIME can be set but have no actual effect.
• MS_SYNCHRONOUS can be set but have no actual effect.

Unsupported mount flags:

• MS_SHARED
• MS_SLAVE
• MS_UNBINDABLE

For more information, see the man page.

umount and umount2

Supported functionality in SCML:

// Unmount a mounted file system
umount(target);

// Unmount a mounted file system with enhanced behavior control
umount2(target, flags = UMOUNT_NOFOLLOW);

Silently-ignored flags:

• MNT_FORCE
• MNT_DETACH
• MNT_EXPIRE

For more information, see the man page.

Event Notifications

inotify_init and inotify_init1

Supported functionality in SCML:

// Create an inotify instance
inotify_init();

// Create an inotify instance with enhanced behavior control
inotify_init1(flags = IN_CLOEXEC | IN_NONBLOCK);

For more information, see the man page.

inotify_add_watch

Supported functionality in SCML:

inotify_events = IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE |
                 IN_CLOSE_NOWRITE | IN_OPEN | IN_CREATE | IN_DELETE |
                 IN_DELETE_SELF | IN_CLOSE;

inotify_controls = IN_ONLYDIR | IN_DONT_FOLLOW | IN_MASK_CREATE |
                   IN_MASK_ADD | IN_ISDIR;

// Add a watch to an initialized inotify instance
inotify_add_watch(fd, pathname, mask = <inotify_events> | <inotify_controls>);

Unsupported event flags:

• IN_MOVED_FROM and IN_MOVED_TO - Move events are not generated
• IN_MOVE_SELF - Self move events are not generated
• IN_UNMOUNT - Unmount events are not generated
• IN_Q_OVERFLOW - Queue overflow events are not generated (events are silently dropped when queue is full)
• IN_ALL_EVENTS - Only includes actually supported events

Unsupported control flags:

• IN_EXCL_UNLINK - Events on unlinked files are not excluded
• IN_ONESHOT - Watches are not automatically removed after the first event

For more information, see the man page.