mntoptparse_t
getmntopts(
const char *options
, const struct mntopt *mopts
, int *flagp
, int *altflagp
)
const
char
*
getmntoptstr(
mntoptparse_t mp
, const char *opt
)
long
getmntoptnum(
mntoptparse_t mp
, const char *opt
)
void
freemntopts(
mntoptparse_t mp
)
)
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.
The string
options
is broken down into a sequence of comma separated tokens.
Each token is looked up in the table described by
mopts
and the bits in
the word referenced by either
flagp
or
altflagp
(depending on the
m_altloc
field of the option's table entry)
are updated.
The flag words are not initialized by
getmntopts().
The table,
mopts,
has the following format:
struct mntopt {
const char *m_option; /* option name */
int m_inverse; /* negative option, e.g., "dev" */
int m_flag; /* bit to set, e.g., MNT_RDONLY */
int m_altloc; /* use altflagp rather than flagp */
};
The members of this structure are:
m_option
m_inverse
)
that the name has the inverse meaning of the bit.
For example,
``suid''
is the string, whereas the mount flag is
MNT_NOSUID
.
In this case, the sense of the string and the flag
are inverted, so the
m_inverse
flag should be set.
m_flag
m_inverse
flag causes these two operations to be reversed.
m_altloc
Each of the user visible
MNT_
flags has a corresponding
MOPT_
macro which defines an appropriate
struct mntopt
entry.
To simplify the program interface and ensure consistency across all
programs, a general purpose macro,
MOPT_STDOPTS
,
is defined which contains an entry for all the generic VFS options.
In addition, the macros
MOPT_FORCE
and
MOPT_UPDATE
exist to enable the
MNT_FORCE
and
MNT_UPDATE
flags to be set.
Finally, the table must be terminated by an entry with a
NULL
first element.
The
getmntoptstr()
function returns the string value of the named option, if such a value
was set it the option string.
The
getmntoptnum()
returns the long value of the named option, if such a value was set it the
option string.
It prints an error message and exits if the value was not
set, or could not be converted from a string to a long.
The
freemntopts()
frees the storage used by
getmntopts(
).
MNT_UPDATE
flag, would also have an
MOPT_UPDATE
entry.
This can be declared and used as follows:
#include <mntopts.h>
static const struct mntopt mopts[] = {
MOPT_STDOPTS,
MOPT_UPDATE,
{ NULL }
};
long val;
mntflags = mntaltflags = 0;
mntoptparse_t mp;
if ((mp = getmntopts(options, mopts, &mntflags, &mntaltflags)) == NULL)
err(1, NULL);
val = getmntoptnum(mp, "rsize");
freemntopts(mp);
)
returns
NULL
if an error occurred.
Note that some bits may already have been set in
flagp
and
altflagp
even if
NULL
is returned.
getmntoptstr(
)
returns
NULL
if the option does not have an argument, or the option string.
getmntoptnum(
)
returns -1 if an error occurred.
)
function displays an error message and exits if an
unrecognized option is encountered.
By default
getmnt_silent
is zero.
)
function appeared in
4.4BSD.
It was moved to the utilities library and enhanced to retrieve option
values in
NetBSD2.0.