NAME

statvfs, fstatvfs − get file system information

SYNOPSIS

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

int statvfs (const char ∗path, struct statvfs ∗buf);

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

DESCRIPTION

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

path 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:

ulongf_bsize;/∗ preferred file system block size ∗/
ulongf_frsize;/∗ fundamental filesystem block size
(if supported) ∗/
ulongf_blocks;/∗ total # of blocks on file system
in units of f_frsize ∗/
ulongf_bfree;/∗ total # of free blocks ∗/
ulongf_bavail;/∗ # of free blocks avail to
              non-superuser ∗/
ulongf_files;/∗ total # of file nodes (inodes) ∗/
ulongf_ffree;/∗ total # of free file nodes ∗/
ulongf_favail;/∗ # of inodes avail to
              non-superuser∗/
fsid_tf_fsid;/∗ file system id (dev for now) ∗/
charf_basetype[FSTYPSZ]; /∗  target fs type name,
              null-terminated ∗/
ulongf_flag;/∗ bit mask of flags ∗/
ulongf_namemax;/∗ maximum file name length ∗/
charf_fstr[32];/∗ file system specific string ∗/
ulongf_filler[16];/∗ reserved for future expansion ∗/

f_basetype contains a null-terminated FSType name of the mounted target (for example, s5 mounted over rfs will contain s5). 

The following flags can be returned in the f_flag field:

ST_RDONLY0x01/∗ read-only file system ∗/
ST_NOSUID0x02/∗ does not support setuid/setgid
              semantics ∗/
ST_NOTRUNC0x04/∗ does not truncate file names
              longer than {NAME_MAX}∗/

fstatvfs 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, creat, dup, fcntl, or pipe system call. 

statvfs fails if one or more of the following are true:

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

EFAULT path or buf points outside the process’s allocated address space. 

EINTR A signal was caught during statvfs execution. 

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

ELOOP Too many symbolic links were encountered in translating path.

EMULTIHOP Components of path require hopping to multiple remote machines and file system type does not allow it. 

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 path 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. 

fstatvfs fails if one or more of the following are true:

EFAULT buf points to an invalid address. 

EBADF fildes is not an open file descriptor. 

EINTR A signal was caught during fstatvfs execution. 

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

DIAGNOSTICS

Upon successful completion a value of 0 is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

SEE ALSO

chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2), read(2), time(2), unlink(2), utime(2), write(2).