GETFSSTAT(2)

NAME
getfsstat - get list of all mounted filesystems

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

int
getfsstat(buf,bufsize,flags)
struct statfs *buf;
int bufsize;
int flags;

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

#define MNAMELEN 90       /* length of buffer for returned name */
struct statfs {
short   f_type;           /* type of filesystem (see below) */
short   f_flags;          /* copy of mount flags */
short   f_bsize;          /* fundamental file system block size */
short   f_iosize;         /* optimal transfer block size */
long    f_blocks;         /* total data blocks in file system */
long    f_bfree;          /* free blocks in fs */
long    f_bavail;         /* free blocks avail to non-superuser */
ino_t   f_files;          /* total file nodes in file system */
ino_t   f_ffree;          /* free file nodes in fs */
u_long  f_fsid[2];        /* file system id */
long    f_spare[4];       /* spare for later */
char    f_mntonname[MNAMELEN];    /* mount point */
char    f_mntfromname[MNAMELEN];  /* mounted filesystem */
};
/*
* File system types. - Only UFS is supported so the other types are not
* given.
*/
#define	MOUNT_NONE	0
#define	MOUNT_UFS	1	/* Fast Filesystem */

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 is currently unused. In 4.4BSD systems the usage is 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 Thus, some of the information will be out of date, but getfsstat() will not block waiting for information from a filesystem that is unable to respond.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.