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 file system. Buf is a pointer to a statfs structure defined as follows:

    typedef struct { int32_t val[2]; } fsid_t;
    #define MFSNAMELEN   15 /* length of fs type name, not inc. nul */
    #define MNAMELEN     90	/* length of buffer for returned name */
    struct statfs {
        short   f_otype;	/* type of file system (reserved: zero) */
        short   f_oflags;	/* copy of mount flags (reserved: zero) */
        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 (super-user only) */
        uid_t   f_owner;	/* user that mounted the file system */
        short   f_reserved1;	/* reserved for future use */
        short   f_type;	/* type of file system (reserved) */
        long    f_flags;	/* copy of mount flags (reserved) */
        long    f_reserved2[2];	/* reserved for future use */
        char    f_fstypename[MFSNAMELEN]; /* fs type name */
        char    f_mntonname[MNAMELEN];    /* directory on which mounted */
        char    f_mntfromname[MNAMELEN];  /* mounted file system */
        char    f_reserved3;	/* reserved for future use */
        long    f_reserved4[4];	/* reserved for future use */
    };

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 {NAME_MAX} characters, or the length of path exceeds {PATH_MAX} 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.