GETFSSTAT(2)

NAME
getfsstat - get list of all mounted filesystems

SYNOPSIS
#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>
int
getfsstat(struct statfs *buf, long bufsize, int flags);

DESCRIPTION
Getfsstat() returns information about all mounted filesystems. Buf is a pointer to statfs structures defined as follows:

    typedef quad fsid_t;
    #define MNAMELEN 32	/* length of buffer for returned name */
    struct statfs {
        short   f_type;	/* type of filesystem (see below) */
        short   f_flags;	/* copy of mount flags */
        long    f_bsize;	/* fundamental filesystem block size */
        long    f_iosize;	/* optimal transfer block size */
        long    f_blocks;	/* total data blocks in filesystem */
        long    f_bfree;	/* free blocks in fs */
        long    f_bavail;	/* free blocks avail to non-superuser */
        long    f_files;	/* total file nodes in filesystem */
        long    f_ffree;	/* free file nodes in fs */
        fsid_t  f_fsid;	/* filesystem id */
        long    f_spare[6];	/* spare for later */
        char    f_mntonname[MNAMELEN]; /* directory on which mounted */
        char    f_mntfromname[MNAMELEN]; /* mounted filesystem */
    };
    /*
     * File system types.
     */
    #define	MOUNT_UFS	1
    #define	MOUNT_NFS	2
    #define	MOUNT_PC	3

Fields that are undefined for a particular filesystem are set to -1. The buffer is filled with an array of fsstat structures, one for each mounted filesystem up to the size specified by bufsize.

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

Normally flags should be specified as MNT_WAIT. If flags is set to MNT_NOWAIT, getfsstat() will return the information it has available without requesting an update from each filesystem. Thus, some of the information will be out of date, but getfsstat() will not block waiting for information from a filesystem that is unable to respond.

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

ERRORS
Getfsstat() fails if one or more of the following are true:

EFAULT
    Buf points to an invalid address.

EIO An I/O error occurred while reading from or writing to the filesystem.

SEE ALSO
statfs(2), fstab(5), mount(8)

HISTORY
The getfsstat function first appeared in 4.4BSD.