statfs(2) - Manual pages

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 quad fsid_t;

#define MFSNAMELEN	16	/* length of fs type name, including null */
#define	MNAMELEN	90	/* length of buffer for returned name */

struct statfs {
	short	f_type;			/* filesystem type number */
	short	f_flags;		/* copy of mount flags */
	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 */
	long	f_spare[4];		/* 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 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.
[EINVAL]: path contains a character with the high-order bit set.
[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.