STATVFS(2) System Calls STATVFS(2)

NAME

statvfs, fstatvfs - get file system information

SYNOPSIS

#include <sys/types.h>
#include <sys/statvfs.h>

int statvfs(const char *restrict path, struct statvfs *restrict buf);


int fstatvfs(int fildes, struct statvfs *buf);

DESCRIPTION

The statvfs() function returns a "generic superblock" describing a file
system; it can be used to acquire information about mounted file
systems. The buf argument is a pointer to a structure (described below)
that is filled by the function.


The path argument should name a file that resides on that file system.
The file system type is known to the operating system. Read, write, or
execute permission for the named file is not required, but all
directories listed in the path name leading to the file must be
searchable.


The statvfs structure pointed to by buf includes the following members:

u_long f_bsize; /* preferred file system block size */
u_long f_frsize; /* fundamental filesystem block
(size if supported) */
fsblkcnt_t f_blocks; /* total # of blocks on file system
in units of f_frsize */
fsblkcnt_t f_bfree; /* total # of free blocks */
fsblkcnt_t f_bavail; /* # of free blocks avail to
non-privileged user */
fsfilcnt_t f_files; /* total # of file nodes (inodes) */
fsfilcnt_t f_ffree; /* total # of free file nodes */
fsfilcnt_t f_favail; /* # of inodes avail to
non-privileged user*/
u_long f_fsid; /* file system id (dev for now) */
char f_basetype[FSTYPSZ]; /* target fs type name,
null-terminated */
u_long f_flag; /* bit mask of flags */
u_long f_namemax; /* maximum file name length */
char f_fstr[32]; /* file system specific string */
u_long f_filler[16]; /* reserved for future expansion */


The f_basetype member contains a null-terminated FSType name of the
mounted target.


The following values can be returned in the f_flag field:

ST_RDONLY 0x01 /* read-only file system */
ST_NOSUID 0x02 /* does not support setuid/setgid semantics */
ST_NOTRUNC 0x04 /* does not truncate file names longer than
NAME_MAX */


The fstatvfs() function is similar to statvfs(), except that the file
named by path in statvfs() is instead identified by an open file
descriptor fildes obtained from a successful open(2), creat(2), dup(2),
fcntl(2), or pipe(2) function call.

RETURN VALUES

Upon successful completion, 0 is returned. Otherwise, -1 is returned and
errno is set to indicate the error.

ERRORS

The statvfs() and fstatvfs() functions will fail if:

EOVERFLOW
One of the values to be returned cannot be represented
correctly in the structure pointed to by buf.


The statvfs() function will fail if:

EACCES
Search permission is denied on a component of the path
prefix.


EFAULT
The path or buf argument points to an illegal address.


EINTR
A signal was caught during the execution of the statvfs()
function.


EIO
An I/O error occurred while reading the file system.


ELOOP
Too many symbolic links were encountered in translating
path.


ENAMETOOLONG
The length of a path component exceeds NAME_MAX
characters, or the length of path exceeds PATH_MAX
characters.


ENOENT
Either a component of the path prefix or the file
referred to by path does not exist.


ENOLINK
The path argument points to a remote machine and the link
to that machine is no longer active.


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


The fstatvfs() function will fail if:

EBADF
The fildes argument is not an open file descriptor.


EFAULT
The buf argument points to an illegal address.


EINTR
A signal was caught during the execution of the fstatvfs()
function.


EIO
An I/O error occurred while reading the file system.

USAGE

The statvfs() and fstatvfs() functions have transitional interfaces for
64-bit file offsets. See lf64(7).

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

SEE ALSO

chmod(2), chown(2), creat(2), dup(2), fcntl(2), link(2), mknod(2),
open(2), pipe(2), read(2), time(2), unlink(2), utime(2), write(2),
attributes(7), lf64(7), standards(7)

BUGS

The values returned for f_files, f_ffree, and f_favail may not be valid
for NFS mounted file systems.

October 3, 2020 STATVFS(2)