4bc282eb72
The getfsstat(2) function expects a buffer and a count, and returns a count. The confusing part is that the count it takes is a byte count, while the return value is a count of the number of structures it has filled out. Spell this out.
127 lines
3.7 KiB
Groff
127 lines
3.7 KiB
Groff
.\" Copyright (c) 1989, 1991, 1993
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.\" documentation and/or other materials provided with the distribution.
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" without specific prior written permission.
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)getfsstat.2 8.3 (Berkeley) 5/25/95
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.\" $FreeBSD$
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.\"
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.Dd November 20, 2003
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.Dt GETFSSTAT 2
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.Os
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.Sh NAME
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.Nm getfsstat
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.Nd get list of all mounted file systems
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/ucred.h
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.In sys/mount.h
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.Ft int
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.Fn getfsstat "struct statfs *buf" "long bufsize" "int flags"
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.Sh DESCRIPTION
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The
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.Fn getfsstat
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system call
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returns information about all mounted file systems.
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The
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.Fa buf
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argument
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is a pointer to
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.Vt statfs
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structures, as described in
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.Xr statfs 2 .
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.Pp
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Fields that are undefined for a particular file system are set to -1.
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The buffer is filled with an array of
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.Fa fsstat
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structures, one for each mounted file system
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up to the byte count specified by
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.Fa bufsize .
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Note, the
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.Fa bufsize
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argument is the number of bytes that
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.Fa buf
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can hold, not the count of statfs structures it will hold.
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.Pp
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If
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.Fa buf
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is given as NULL,
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.Fn getfsstat
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returns just the number of mounted file systems.
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.Pp
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Normally
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.Fa flags
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should be specified as
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.Dv MNT_WAIT .
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If
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.Fa flags
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is set to
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.Dv MNT_NOWAIT ,
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.Fn getfsstat
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will return the information it has available without requesting
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an update from each file system.
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Thus, some of the information will be out of date, but
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.Fn getfsstat
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will not block waiting for information from a file system that is
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unable to respond.
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.Sh RETURN VALUES
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Upon successful completion, the number of
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.Fa fsstat
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structures is returned.
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Otherwise, -1 is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn getfsstat
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system call
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fails if one or more of the following are true:
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.Bl -tag -width Er
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.It Bq Er EFAULT
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The
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.Fa buf
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argument
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points to an invalid address.
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.It Bq Er EIO
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An
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.Tn I/O
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error occurred while reading from or writing to the file system.
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.El
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.Sh SEE ALSO
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.Xr statfs 2 ,
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.Xr fstab 5 ,
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.Xr mount 8
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.Sh HISTORY
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The
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.Fn getfsstat
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system call first appeared in
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.Bx 4.4 .
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