NetBSD/lib/libc/sys/statfs.2

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.\"	@(#)statfs.2	8.5 (Berkeley) 5/24/95
.\"
.Dd May 24, 1995
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs ,
.Nm fstatfs
.Nd get file system statistics
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn statfs "const char *path" "struct statfs *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Sh DESCRIPTION
.Fn statfs
returns information about a mounted file system.
.Fa path
is the path name of any file within the mounted file system.
.Fa buf
is a pointer to a
.Nm statfs
structure defined as follows:
.Bd -literal
typedef struct { int32_t val[2]; } fsid_t;	/* file system id type */

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

struct statfs {
    short   f_type;	/* type of file system (unused; zero) */
    u_short f_oflags;	/* deprecated 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 file system */
    long    f_flags;    /* copy of mount flags */
    long    f_syncwrites; /* count of sync writes since mount */
    long    f_asyncwrites; /* count of async writes since mount */
    long    f_spare[1]; /* spare for later */
    char    f_fstypename[MFSNAMELEN]; /* fs type name */
    char    f_mntonname[MNAMELEN];    /* directory on which mounted */
    char    f_mntfromname[MNAMELEN];  /* mounted file system */
};
.Ed
.Pp
The flags that may be returned include:
.Bl -tag -width MNT_SYNCHRONOUS
.It Dv MNT_RDONLY
The filesystem is mounted read-only;
Even the super-user may not write on it.
.It Dv MNT_NOEXEC
Files may not be executed from the filesystem.
.It Dv MNT_NOSUID
Setuid and setgid bits on files are not honored when they are executed.
.It Dv MNT_NODEV
Special files in the filesystem may not be opened.
.It Dv MNT_SYNCHRONOUS
All I/O to the filesystem is done synchronously.
.It Dv MNT_ASYNC
No filesystem I/O is done synchronously.
.It Dv MNT_UNION
Union with underlying filesystem.
.It Dv MNT_NOCOREDUMP
Don't write core dumps to this file system.
.It Dv MNT_NOATIME
Never update access times.
.It Dv MNT_SYMPERM
Recognize symbolic link permission.
.It Dv MNT_NODEVMTIME
Never update mod. times for device files.
.It Dv MNT_SOFTDEP
Use soft dependencies.
.It Dv MNT_LOCAL
The filesystem resides locally.
.It Dv MNT_QUOTA
The filesystem has quotas enabled on it.
.It Dv MNT_ROOTFS
Identifies the root filesystem.
.It Dv MNT_EXRDONLY
The filesystem is exported read-only.
.It Dv MNT_EXPORTED
The filesystem is exported for both reading and writing.
.It Dv MNT_DEFEXPORTED
The filesystem is exported for both reading and writing to any Internet host.
.It Dv MNT_EXPORTANON
The filesystem maps all remote accesses to the anonymous user.
.It Dv MNT_EXKERB
The filesystem is exported with Kerberos uid mapping.
.It Dv MNT_EXNORESPORT
Don't enforce reserved ports (NFS).
.It Dv MNT_EXPUBLIC
Public export (WebNFS).
.El
.Pp
Fields that are undefined for a particular file system are set to -1.
.Fn fstatfs
returns the same information about an open file referenced by descriptor
.Fa fd .
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn statfs
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa path
is not a directory.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds 
.Dv {NAME_MAX}
characters, or the length of
.Fa path
exceeds 
.Dv {PATH_MAX}
characters.
.It Bq Er ENOENT
The file referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
.Fa buf
or
.Fa path
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Pp
.Fn fstatfs
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa fd
is not a valid open file descriptor.
.It Bq Er EFAULT
.Fa buf
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Sh HISTORY
The
.Fn statfs
function first appeared in
.Bx 4.4 .