Reference

fsctl(2)

control filesystems

NAME

fsctl – control filesystems

SYNOPSIS

#include <sys/attr.h>

#include <sys/ioctl.h>

int

fsctl(const char *path, unsigned long request, void *data, unsigned long options);

DESCRIPTION

The fsctl() function manipulates the filesystem controlling mounted volumes. In particular, many filesystem-specific operating characteristics of mounted filesystems may be controlled with fsctl() requests. fsctl() requests can also be used to extract filesystem-specific information for a mounted volumes.

path is the path name of any file within the mounted filesystem. An fsctl request has encoded in it whether the argument is an “in” parameter or “out” parameter, and the size of the argument data in bytes. Values for request are entirely filesystem-specific except for the following, defined in ⟨sys/fsctl.h⟩:

FSGETMOUNTINFOSIZE

Return size of mount info data.

Macros and defines used in specifying an fsctl request are the same as for ioctl() requests and are located in the file ⟨sys/ioccom.h⟩. options may specify special flags for the processing of the fsctl() call. The options are specified by or'ing the option values. The following option bits are defined:

FSOPT_NOFOLLOW

If this bit is set, fsctl() will not follow a symlink if it occurs as the last component of path.

FSOPT_NOFOLLOW_ANY

If this bit is set, fsctl() will not follow a symlink if it occurs as the last component of path. In addition an error is returned if a symlink is encountered before the last component of path.

FSOPT_UNIQUE

If this bit is set, the path lookup will fail if the target file has multiple hard links.

The options argument is passed to the filesystem, which may define and handle additional options bit values.

RETURN VALUES

If an error has occurred, a value of -1 is returned and errno is set to indicate the error.

ERRORS

fsctl() will fail if:

[ENOTDIR]

A component of the path prefix is not a directory.

[ENAMETOOLONG]

A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters.

[ENOENT]

The named file does not exist.

[EACCES]

Search permission is denied for a component of the path prefix.

[ELOOP]

Too many symbolic links were encountered in translating the pathname.

[EFAULT]

path or data points to an invalid address.

[EIO]

An I/O error occurred while reading from or writing to the file system.

[EINVAL]

request or data is not valid.

[ENOTCAPABLE]

if FSOPT_UNIQUE was passed and path has multiple hard links.

SEE ALSO

getattrlist(2), ioctl(2), setattrlist(2)

HISTORY

The fsctl() function call appeared in Mac OS X version 10.0.

History