NAME

getfsstat — get list of all mounted file systems

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>

int
getfsstat(struct statfs *buf, long bufsize, int mode);

DESCRIPTION

The getfsstat() system call returns information about all mounted file systems. The buf argument is a pointer to statfs structures, as described in statfs(2).

Fields that are undefined for a particular file system are set to -1. The buffer is filled with an array of statfs structures, one for each mounted file system up to the byte count specified by bufsize. Note, the bufsize argument is the number of bytes that buf can hold, not the count of statfs structures it will hold.

If buf is given as NULL, getfsstat() returns just the number of mounted file systems.

Normally mode should be specified as MNT_WAIT. If mode is set to MNT_NOWAIT, getfsstat() will return the information it has available without requesting an update from each file system. Thus, some of the information will be out of date, but getfsstat() will not block waiting for information from a file system that is unable to respond. It will also skip any file system that is in the process of being unmounted, even if the unmount would eventually fail.

RETURN VALUES

Upon successful completion, the number of statfs structures is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS

The getfsstat() system call fails if one or more of the following are true:

[EFAULT]: The buf argument points to an invalid address.
[EINVAL]: mode is set to a value other than MNT_WAIT or MNT_NOWAIT.
[EIO]: An I/O error occurred while reading from or writing to the file system.
[EINTEGRITY]: Corrupted data was detected while reading from the file system.

HISTORY

The getfsstat() system call first appeared in 4.4BSD.