STATFS(2)

NAME
statfs - get file system statistics

SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
int
statfs(const char *path, struct statfs *buf);
int
fstatfs(int fd, struct statfs *buf);

DESCRIPTION
Statfs() returns information about a mounted file system. Path is the path name of any file within the mounted filesystem. Buf is a pointer to a statfs() structure 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];	  /* mount point */
    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 file system are set to -1. Fstatfs() returns the same information about an open file referenced by descriptor fd.

RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

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

[ENOTDIR]
    A component of the path prefix of Path is not a directory.

[ENAMETOOLONG]
    The length of a component of path exceeds 255 characters, or the length of path exceeds 1023 characters.

[ENOENT]
    The file referred to by path does not exist.

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

[ELOOP]
    Too many symbolic links were encountered in translating path.

[EFAULT]
    Buf or path points to an invalid address.

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

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

[EBADF]
    Fd is not a valid open file descriptor.

[EFAULT]
    Buf points to an invalid address.

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

HISTORY
The statfs() function first appeared in 4.4BSD.