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Diffstat (limited to 'sbin/mount_ifs/getmntopts.3')
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diff --git a/sbin/mount_ifs/getmntopts.3 b/sbin/mount_ifs/getmntopts.3 new file mode 100644 index 0000000..642c57a --- /dev/null +++ b/sbin/mount_ifs/getmntopts.3 @@ -0,0 +1,163 @@ +.\" Copyright (c) 1994 +.\" 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. +.\" +.\" @(#)getmntopts.3 8.1 (Berkeley) 3/27/94 +.\" +.Dd March 27, 1994 +.Dt GETMNTOPTS 3 +.Os BSD 4.4 +.Sh NAME +.Nm getmntopts +.Nd scan mount options +.Sh SYNOPSIS +.Fd #include <mntopts.h> +.Ft void +.Fn getmntopts "char *options" "struct mntopt *mopts" "int *flagp" +.Sh DESCRIPTION +The +.Nm getmntopts +function takes a comma separated option list and a list +of valid option names, and computes the bitmask +corresponding to the requested set of options. +.Pp +The string +.Dv options +is broken down into a sequence of comma separated tokens. +Each token is looked up in the table described by +.Dv mopts +and the bits in +the word referenced by +.Dv flagp +are updated. +The flag word is not initialized by +.Nm getmntopt . +The table, +.Dv mopts , +has the following format: +.Bd -literal +struct mntopt { + char *m_option; /* option name */ + int m_inverse; /* is this a negative option, eg "dev" */ + int m_flag; /* bit to set, eg MNT_RDONLY */ +}; +.Ed +.Pp +The members of this structure are: +.Bl -tag -width m_inverse +.It Fa m_option +the option name, +for example +.Dq suid . +.It Fa m_inverse +tells +.Nm getmntopts +that the name has the inverse meaning of the +bit. +For example, +.Dq suid +is the string, whereas the +mount flag is +.Dv MNT_NOSUID . +In this case, the sense of the string and the flag +are inverted, so the +.Dv m_inverse +flag should be set. +.It Fa m_flag +the value of the bit to be set or cleared in +the flag word when the option is recognized. +The bit is set when the option is discovered, +but cleared if the option name was preceded +by the letters +.Dq no . +The +.Dv m_inverse +flag causes these two operations to be reversed. +.El +.Pp +Each of the user visible +.Dv MNT_ +flags has a corresponding +.Dv MOPT_ +macro which defines an appropriate +.Li "struct mntopt" +entry. +To simplify the program interface and ensure consistency across all +programs, a general purpose macro, +.Dv MOPT_STDOPTS , +is defined which +contains an entry for all the generic VFS options. +In addition, the macros +.Dv MOPT_FORCE +and +.Dv MOPT_UPDATE +exist to enable the +.Dv MNT_FORCE +and +.Dv MNT_UPDATE +flags to be set. +Finally, the table must be terminated by an entry with a NULL +first element. +.Sh EXAMPLES +Most commands will use the standard option set. +Local filesystems which support the +.Dv MNT_UPDATE +flag, would also have an +.Dv MOPT_UPDATE +entry. +This can be declared and used as follows: +.Bd -literal +#include "mntopts.h" + +struct mntopt mopts[] = { + MOPT_STDOPTS, + MOPT_UPDATE, + { NULL } +}; + + ... + mntflags = 0; + ... + getmntopts(options, mopts, &mntflags) + ... +.Ed +.Sh DIAGNOSTICS +The +.Nm getmntopts +function displays an error message and exits if an +unrecognized option is encountered. +.Sh SEE ALSO +.Xr err 3 , +.Xr mount 8 +.Sh HISTORY +The +.Fn getmntopts +function appeared in +.Bx 4.4 . |
