GETFSSTAT(2)

NAME
getfsstat - get list of all mounted filesystems

LIBRARY
libc

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 struct fsid { int32_t val[2]; } fsid_t;	/* file system id type */
    /*
     * file system statistics
     */
    #define MFSNAMELEN 16	/* length of fs type name, including null */
    #define MNAMELEN   90	/* length of buffer for returned name */
    struct statfs {
        long    f_spare2;		/* placeholder */
        long    f_bsize;		/* fundamental file system block size */
        long    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 */
        long    f_files;		/* total file nodes in file system */
        long    f_ffree;		/* free file nodes in fs */
        fsid_t  f_fsid;		/* file system id */
        uid_t   f_owner;		/* user that mounted the filesystem */
        int     f_type;		/* type of filesystem (see below) */
        int     f_flags;		/* copy of mount flags */
        long    f_spare[2];		/* spare for later */
        char    f_fstypename[MFSNAMELEN];/* fs type name */
        char    f_mntonname[MNAMELEN];/* directory on which mounted */
        char    f_mntfromname[MNAMELEN];/* mounted filesystem */
    };

The flags that may be returned include:

MNT_RDONLY
    The filesystem is mounted read-only; Even the super-user may not write on it.

MNT_NOEXEC
    Files may not be executed from the filesystem.

MNT_NOSUID
    Setuid and setgid bits on files are not honored when they are executed.

MNT_NODEV
    Special files in the filesystem may not be opened.

MNT_SYNCHRONOUS
    All I/O to the filesystem is done synchronously.

MNT_ASYNCHRONOUS
    No filesystem I/O is done synchronously.

MNT_LOCAL
    The filesystem resides locally.

MNT_QUOTA
    The filesystem has quotas enabled on it.

MNT_ROOTFS
    Identifies the root filesystem.

MNT_EXRDONLY
    The filesystem is exported read-only.

MNT_EXPORTED
    The filesystem is exported for both reading and writing.

MNT_DEFEXPORTED
    The filesystem is exported for both reading and writing to any Internet host.

MNT_EXPORTANON
    The filesystem maps all remote accesses to the anonymous user.

MNT_EXKERB
    The filesystem is exported with Kerberos uid mapping.

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.