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Diffstat (limited to 'lib/libc/sys/mount.2')
| -rw-r--r-- | lib/libc/sys/mount.2 | 324 |
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diff --git a/lib/libc/sys/mount.2 b/lib/libc/sys/mount.2 new file mode 100644 index 0000000..d4959ed --- /dev/null +++ b/lib/libc/sys/mount.2 @@ -0,0 +1,324 @@ +.\" Copyright (c) 1980, 1989, 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. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. 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. +.\" +.\" @(#)mount.2 8.3 (Berkeley) 5/24/95 +.\" $FreeBSD$ +.\" +.Dd May 24, 1995 +.Dt MOUNT 2 +.Os BSD 4 +.Sh NAME +.Nm mount , +.Nm unmount +.Nd mount or dismount a filesystem +.Sh SYNOPSIS +.Fd #include <sys/param.h> +.Fd #include <sys/mount.h> +.Ft int +.Fn mount "const char *type" "const char *dir" "int flags" "void *data" +.Ft int +.Fn unmount "const char *dir" "int flags" +.Sh DESCRIPTION +The +.Fn mount +function grafts +a filesystem object onto the system file tree +at the point +.Ar dir . +The argument +.Ar data +describes the filesystem object to be mounted. +The argument +.Ar type +tells the kernel how to interpret +.Ar data +(See +.Ar type +below). +The contents of the filesystem +become available through the new mount point +.Ar dir . +Any files in +.Ar dir +at the time +of a successful mount are swept under the carpet so to speak, and +are unavailable until the filesystem is unmounted. +.Pp +The following +.Ar flags +may be specified to +suppress default semantics which affect filesystem access. +.Bl -tag -width MNT_SYNCHRONOUS +.It Dv MNT_RDONLY +The filesystem should be treated as read-only; +Even the super-user may not write on it. +Specifying MNT_UPDATE without this option will upgrade +a read-only filesystem to read/write. +.It Dv MNT_NOEXEC +Do not allow files to be executed from the filesystem. +.It Dv MNT_NOSUID +Do not honor setuid or setgid bits on files when executing them. +.It Dv MNT_NOATIME +Disable update of file access times. +.It Dv MNT_NODEV +Do not interpret special files on the filesystem. +.It Dv MNT_SUIDDIR +Directories with the SUID bit set chown new files to their own owner. +.It Dv MNT_SYNCHRONOUS +All I/O to the filesystem should be done synchronously. +.It Dv MNT_ASYNC +All I/O to the filesystem should be done asynchronously. +.It Dv MNT_FORCE +Force a read-write mount even if the filesystem appears to be unclean. +Dangerous. +.It Dv MNT_NOCLUSTERR +Disable read clustering. +.It Dv MNT_NOCLUSTERW +Disable write clustering. +.El +.Pp +The flag +.Dv MNT_UPDATE +indicates that the mount command is being applied +to an already mounted filesystem. +This allows the mount flags to be changed without requiring +that the filesystem be unmounted and remounted. +Some filesystems may not allow all flags to be changed. +For example, +many filesystems will not allow a change from read-write to read-only. +.Pp +The flag +.Dv MNT_RELOAD +causes the vfs subsystem to update its data structures pertaining to +the specified already mounted filesystem. +.Pp +The +.Fa type +argument names the filesystem. +The types of filesystems known to the system can be obtained with +.Xr lsvfs 1 . +.Pp +.Fa Data +is a pointer to a structure that contains the type +specific arguments to mount. +The format for these argument structures is described in the +manual page for each filesystem. +By convention filesystem manual pages are named +by prefixing ``mount_'' to the name of the filesystem as returned by +.Xr lsvfs 1 . +Thus the +.Nm NFS +filesystem is described by the +.Xr mount_nfs 8 +manual page. +.Pp +The +.Fn unmount +function call disassociates the filesystem from the specified +mount point +.Fa dir . +.Pp +The +.Fa flags +argument may specify +.Dv MNT_FORCE +to specify that the filesystem should be forcibly unmounted or made read-only +(if MNT_UPDATE and MNT_RDONLY are also specified) +even if files are still active. +Active special devices continue to work, +but any further accesses to any other active files result in errors +even if the filesystem is later remounted. +.Pp +The +.Dv MNT_SUIDDIR +option requires the SUIDDIR option to have been compiled into the kernel +to have any effect. +See the +.Xr mount 8 +and +.Xr chmod 2 +pages for more information. +.Sh RETURN VALUES +The +.Fn mount +returns the value 0 if the mount was successful, otherwise -1 is returned +and the variable +.Va errno +is set to indicate the error. +.Pp +The +.Fn unmount +function returns the value 0 if the umount succeeded; otherwise -1 is returned +and the variable +.Va errno +is set to indicate the error. +.Sh ERRORS +The +.Fn mount +function will fail when one of the following occurs: +.Bl -tag -width [ENOTBLK] +.It Bq Er EPERM +The caller is not the super-user. +.It Bq Er ENAMETOOLONG +A component of a pathname exceeded 255 characters, +or the entire length of a path name exceeded 1023 characters. +.It Bq Er ELOOP +Too many symbolic links were encountered in translating a pathname. +.It Bq Er ENOENT +A component of +.Fa dir +does not exist. +.It Bq Er ENOTDIR +A component of +.Ar name +is not a directory, +or a path prefix of +.Ar special +is not a directory. +.It Bq Er EBUSY +Another process currently holds a reference to +.Fa dir . +.It Bq Er EFAULT +.Fa Dir +points outside the process's allocated address space. +.El +.Pp +The following errors can occur for a +.Em ufs +filesystem mount: +.Bl -tag -width [ENOTBLK] +.It Bq Er ENODEV +A component of ufs_args +.Ar fspec +does not exist. +.It Bq Er ENOTBLK +.Ar Fspec +is not a block device. +.It Bq Er ENXIO +The major device number of +.Ar fspec +is out of range (this indicates no device driver exists +for the associated hardware). +.It Bq Er EBUSY +.Ar Fspec +is already mounted. +.It Bq Er EMFILE +No space remains in the mount table. +.It Bq Er EINVAL +The super block for the filesystem had a bad magic +number or an out of range block size. +.It Bq Er ENOMEM +Not enough memory was available to read the cylinder +group information for the filesystem. +.It Bq Er EIO +An I/O error occurred while reading the super block or +cylinder group information. +.It Bq Er EFAULT +.Ar Fspec +points outside the process's allocated address space. +.El +.Pp +The following errors can occur for a +.Em nfs +filesystem mount: +.Bl -tag -width [ENOTBLK] +.It Bq Er ETIMEDOUT +.Em Nfs +timed out trying to contact the server. +.It Bq Er EFAULT +Some part of the information described by nfs_args +points outside the process's allocated address space. +.El +.Pp +The following errors can occur for a +.Em mfs +filesystem mount: +.Bl -tag -width [ENOTBLK] +.It Bq Er EMFILE +No space remains in the mount table. +.It Bq Er EINVAL +The super block for the filesystem had a bad magic +number or an out of range block size. +.It Bq Er ENOMEM +Not enough memory was available to read the cylinder +group information for the filesystem. +.It Bq Er EIO +A paging error occurred while reading the super block or +cylinder group information. +.It Bq Er EFAULT +.Em Name +points outside the process's allocated address space. +.El +.Pp +The +.Fn unmount +function may fail with one of the following errors: +.Bl -tag -width [ENOTBLK] +.It Bq Er EPERM +The caller is not the super-user. +.It Bq Er ENOTDIR +A component of the path is not a directory. +.It Bq Er ENAMETOOLONG +A component of a pathname exceeded 255 characters, +or an entire path name exceeded 1023 characters. +.It Bq Er ELOOP +Too many symbolic links were encountered in translating the pathname. +.It Bq Er EINVAL +The requested directory is not in the mount table. +.It Bq Er EBUSY +A process is holding a reference to a file located +on the filesystem. +.It Bq Er EIO +An I/O error occurred while writing cached filesystem information. +.It Bq Er EFAULT +.Fa Dir +points outside the process's allocated address space. +.El +.Pp +A +.Em ufs +or +.Em mfs +mount can also fail if the maximum number of filesystems are currently +mounted. +.Sh SEE ALSO +.Xr lsvfs 1 , +.Xr mfs 8 , +.Xr mount 8 , +.Xr umount 8 +.Sh BUGS +Some of the error codes need translation to more obvious messages. +.Sh HISTORY +.Fn Mount +and +.Fn unmount +function calls appeared in +.At v6 . |
