STATFS(2) BSD System Calls Manual STATFS(2)
NAME
statfs, statfs64, fstatfs, fstatfs64 -- get file system statistics
SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
int
statfs(const char *path, struct statfs *buf);
int
statfs64(const char *path, struct statfs64 *buf);
int
fstatfs(int fd, struct statfs *buf);
int
fstatfs64(int fd, struct statfs64 *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 or statfs64 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 */
#define MFSTYPENAMELEN 16 /* length of fs type name including null */
#define MAXPATHLEN 1024
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 */
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 */
};
struct statfs64 {
uint32_t f_bsize; /* fundamental file system block size */
int32_t f_iosize; /* optimal transfer block size */
uint64_t f_blocks; /* total data blocks in file system */
uint64_t f_bfree; /* free blocks in fs */
uint64_t f_bavail; /* free blocks avail to non-superuser */
uint64_t f_files; /* total file nodes in file system */
uint64_t f_ffree; /* free file nodes in fs */
fsid_t f_fsid; /* file system id */
uid_t f_owner; /* user that mounted the filesystem */
uint32_t f_type; /* type of filesystem */
uint32_t f_flags; /* copy of mount exported flags */
uint32_t f_fssubtype; /* fs sub-type (flavor) */
char f_fstypename[MFSTYPENAMELEN]; /* fs type name */
char f_mntonname[MAXPATHLEN]; /* directory on which mounted */
char f_mntfromname[MAXPATHLEN]; /* mounted filesystem */
uint32_t f_reserved[8]; /* 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.
FLAGS
These are some of the flags that may be present in the f_flags field.
MNT_RDONLY A read-only filesystem
MNT_SYNCHRONOUS File system is written to synchronously
MNT_NOEXEC Can't exec from filesystem
MNT_NOSUID Setuid bits are not honored on this filesystem
MNT_NODEV Don't interpret special files
MNT_UNION Union with underlying filesysten
MNT_ASYNC File system written to asynchronously
MNT_EXPORTED File system is exported File system is stored locally
MNT_QUOTA Quotas are enabled on this file system
MNT_ROOTFS This file system is the root of the file system
MNT_DOVOLFS File system supports volfs
MNT_DONTBROWSE File system is not appropriate path to user data
MNT_UNKNOWNPERMISSIONS
VFS will ignore ownership information on filesystem objects
MNT_AUTOMOUNTED File system was mounted by automounter
MNT_JOURNALED File system is journaled
MNT_DEFWRITE File system should defer writes
MNT_MULTILABEL MAC support for individual labels
CAVEATS
In Mac OS X versions before 10.4, f_iosize is 4096. On these older systems, use MAXBSIZE instead.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global vari-able variable
able 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. The statfs64() and fstatfs64() first appeared in Max OS
X 10.5 (Leopard).
BSD February 11, 1994 BSD
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