freebsd-src/lib/libsys/getfsstat.2

.\" Copyright (c) 1989, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd March 30, 2020
.Dt GETFSSTAT 2
.Os
.Sh NAME
.Nm getfsstat
.Nd get list of all mounted file systems
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/param.h
.In sys/ucred.h
.In sys/mount.h
.Ft int
.Fn getfsstat "struct statfs *buf" "long bufsize" "int mode"
.Sh DESCRIPTION
The
.Fn getfsstat
system call
returns information about all mounted file systems.
The
.Fa buf
argument
is a pointer to
.Vt statfs
structures, as described in
.Xr statfs 2 .
.Pp
Fields that are undefined for a particular file system are set to -1.
The buffer is filled with an array of
.Fa statfs
structures, one for each mounted file system
up to the byte count specified by
.Fa bufsize .
Note, the
.Fa bufsize
argument is the number of bytes that
.Fa buf
can hold, not the count of statfs structures it will hold.
.Pp
If
.Fa buf
is given as NULL,
.Fn getfsstat
returns just the number of mounted file systems.
.Pp
Normally
.Fa mode
should be specified as
.Dv MNT_WAIT .
If
.Fa mode
is set to
.Dv MNT_NOWAIT ,
.Fn getfsstat
will return the information it has available without requesting
an update from each file system.
Thus, some of the information will be out of date, but
.Fn getfsstat
will not block waiting for information from a file system that is
unable to respond.
It will also skip any file system that is in the process of being
unmounted, even if the unmount would eventually fail.
.Sh RETURN VALUES
Upon successful completion, the number of
.Fa statfs
structures is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn getfsstat
system call
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EFAULT
The
.Fa buf
argument
points to an invalid address.
.It Bq Er EINVAL
.Fa mode
is set to a value other than
.Dv MNT_WAIT
or
.Dv MNT_NOWAIT .
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er EINTEGRITY
Corrupted data was detected while reading from the file system.
.El
.Sh SEE ALSO
.Xr statfs 2 ,
.Xr fstab 5 ,
.Xr mount 8
.Sh HISTORY
The
.Fn getfsstat
system call first appeared in
.Bx 4.4 .
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" Copyright (c) 1989, 1991, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" modification, are permitted provided that the following conditions`
			`.\" are met:`
			`.\" 1. Redistributions of source code must retain the above copyright`
			`.\" notice, this list of conditions and the following disclaimer.`
			`.\" 2. Redistributions in binary form must reproduce the above copyright`
			`.\" notice, this list of conditions and the following disclaimer in the`
			`.\" documentation and/or other materials provided with the distribution.`
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96 2017-02-28 23:42:47 +00:00			`.\" 3. Neither the name of the University nor the names of its contributors`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" may be used to endorse or promote products derived from this software`
			`.\" without specific prior written permission.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
			`.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE`
			`.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`.\" SUCH DAMAGE.`
			`.\"`
Document EINTEGRITY errors for many system calls. EINTEGRITY was previously documented as a UFS-specific error for mount(2). This documents EINTEGRITY as a filesystem-independent error that may be reported by the backing store of a filesystem. While here, document EIO as a filesystem-independent error for both mount(2) and posix_fadvise(2). EIO was previously only documented for UFS for mount(2). Reviewed by: mckusick Suggested by: mckusick MFC after: 2 weeks Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D24168 2020-03-30 21:44:00 +00:00			`.Dd March 30, 2020`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Dt GETFSSTAT 2`
			`.Os`
			`.Sh NAME`
			`.Nm getfsstat`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`.Nd get list of all mounted file systems`
Introduce ".Lb" macro to libc manpages. More libraries manpages updates following. 2000-04-21 09:42:15 +00:00			`.Sh LIBRARY`
			`.Lb libc`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In sys/param.h`
			`.In sys/ucred.h`
			`.In sys/mount.h`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Ft int`
Rename the 'flags' argument to getfsstat() to 'mode' and validate it. This argument is not a bitmask of flags, but only accepts a single value. Fail with EINVAL if an invalid value is passed to 'flag'. Rename the 'flags' argument to getmntinfo(3) to 'mode' as well to match. This is a followup to r308088. Reviewed by: kib MFC after: 1 month 2016-12-27 20:21:11 +00:00			`.Fn getfsstat "struct statfs *buf" "long bufsize" "int mode"`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh DESCRIPTION`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`The`
			`.Fn getfsstat`
			`system call`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`returns information about all mounted file systems.`
mdoc(7) police: "The .Fa argument.". 2002-12-19 09:40:28 +00:00			`The`
			`.Fa buf`
			`argument`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`is a pointer to`
Add or correct section number in .Xr. Use .Vt or .Fn instead of .Xr when needed 2003-06-08 10:01:52 +00:00			`.Vt statfs`
Replace out of date struct statfs definition with a reference to statfs(2). Approved by: re 2003-11-21 01:30:28 +00:00			`structures, as described in`
			`.Xr statfs 2 .`
Merge from Lite2 onto mainline - - add undelete() and undelete.2 (requires libc minor bump some time) - man page updates 1997-03-11 11:35:56 +00:00			`.Pp`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`Fields that are undefined for a particular file system are set to -1.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`The buffer is filled with an array of`
We operate on 'statfs' structures, not on 'fsstat' structures. MFC after: 3 days 2006-08-15 18:17:03 +00:00			`.Fa statfs`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`structures, one for each mounted file system`
Clarify getfsstat(2) usage. 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. 2004-07-16 01:18:13 +00:00			`up to the byte count specified by`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Fa bufsize .`
Clarify getfsstat(2) usage. 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. 2004-07-16 01:18:13 +00:00			`Note, the`
			`.Fa bufsize`
			`argument is the number of bytes that`
			`.Fa buf`
			`can hold, not the count of statfs structures it will hold.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Pp`
			`If`
			`.Fa buf`
			`is given as NULL,`
			`.Fn getfsstat`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`returns just the number of mounted file systems.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Pp`
			`Normally`
Rename the 'flags' argument to getfsstat() to 'mode' and validate it. This argument is not a bitmask of flags, but only accepts a single value. Fail with EINVAL if an invalid value is passed to 'flag'. Rename the 'flags' argument to getmntinfo(3) to 'mode' as well to match. This is a followup to r308088. Reviewed by: kib MFC after: 1 month 2016-12-27 20:21:11 +00:00			`.Fa mode`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`should be specified as`
			`.Dv MNT_WAIT .`
			`If`
Rename the 'flags' argument to getfsstat() to 'mode' and validate it. This argument is not a bitmask of flags, but only accepts a single value. Fail with EINVAL if an invalid value is passed to 'flag'. Rename the 'flags' argument to getmntinfo(3) to 'mode' as well to match. This is a followup to r308088. Reviewed by: kib MFC after: 1 month 2016-12-27 20:21:11 +00:00			`.Fa mode`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`is set to`
			`.Dv MNT_NOWAIT ,`
			`.Fn getfsstat`
			`will return the information it has available without requesting`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`an update from each file system.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`Thus, some of the information will be out of date, but`
			`.Fn getfsstat`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`will not block waiting for information from a file system that is`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`unable to respond.`
Document that getfsstat(2) called with MNT_NOWAIT skips file systems that are in the process of being unmounted. Reviewed by: des@ (earlier version) MFC after: 1 month 2016-11-06 19:37:22 +00:00			`It will also skip any file system that is in the process of being`
			`unmounted, even if the unmount would eventually fail.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh RETURN VALUES`
			`Upon successful completion, the number of`
We operate on 'statfs' structures, not on 'fsstat' structures. MFC after: 3 days 2006-08-15 18:17:03 +00:00			`.Fa statfs`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`structures is returned.`
			`Otherwise, -1 is returned and the global variable`
			`.Va errno`
			`is set to indicate the error.`
			`.Sh ERRORS`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`The`
			`.Fn getfsstat`
			`system call`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`fails if one or more of the following are true:`
			`.Bl -tag -width Er`
mdoc(7) police: Er macro usage cleanup. 2000-11-22 16:02:00 +00:00			`.It Bq Er EFAULT`
mdoc(7) police: "The .Fa argument.". 2002-12-19 09:40:28 +00:00			`The`
			`.Fa buf`
			`argument`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`points to an invalid address.`
Rename the 'flags' argument to getfsstat() to 'mode' and validate it. This argument is not a bitmask of flags, but only accepts a single value. Fail with EINVAL if an invalid value is passed to 'flag'. Rename the 'flags' argument to getmntinfo(3) to 'mode' as well to match. This is a followup to r308088. Reviewed by: kib MFC after: 1 month 2016-12-27 20:21:11 +00:00			`.It Bq Er EINVAL`
			`.Fa mode`
			`is set to a value other than`
			`.Dv MNT_WAIT`
			`or`
			`.Dv MNT_NOWAIT .`
mdoc(7) police: Er macro usage cleanup. 2000-11-22 16:02:00 +00:00			`.It Bq Er EIO`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`An`
			`.Tn I/O`
Uniformly refer to a file system as "file system". Approved by: re 2002-12-12 17:26:04 +00:00			`error occurred while reading from or writing to the file system.`
Document EINTEGRITY errors for many system calls. EINTEGRITY was previously documented as a UFS-specific error for mount(2). This documents EINTEGRITY as a filesystem-independent error that may be reported by the backing store of a filesystem. While here, document EIO as a filesystem-independent error for both mount(2) and posix_fadvise(2). EIO was previously only documented for UFS for mount(2). Reviewed by: mckusick Suggested by: mckusick MFC after: 2 weeks Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D24168 2020-03-30 21:44:00 +00:00			`.It Bq Er EINTEGRITY`
			`Corrupted data was detected while reading from the file system.`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.El`
			`.Sh SEE ALSO`
			`.Xr statfs 2 ,`
			`.Xr fstab 5 ,`
			`.Xr mount 8`
			`.Sh HISTORY`
			`The`
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages. 1996-08-22 23:31:07 +00:00			`.Fn getfsstat`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`system call first appeared in`
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages. 1996-08-22 23:31:07 +00:00			`.Bx 4.4 .`