.\" .\" Copyright (C) 2007 Chad David . 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(s), this list of conditions and the following disclaimer as .\" the first lines of this file unmodified other than the possible .\" addition of one or more copyright notices. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice(s), this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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 May 19, 2024 .Dt VFS_GETOPT 9 .Os .Sh NAME .Nm vfs_getopt , .Nm vfs_getopts , .Nm vfs_flagopt , .Nm vfs_scanopt , .Nm vfs_copyopt , .Nm vfs_filteropt , .Nm vfs_setopt , .Nm vfs_setopt_part , .Nm vfs_setopts .Nd "manipulate mount options and their values" .Sh SYNOPSIS .In sys/param.h .In sys/mount.h .Ft int .Fo vfs_getopt .Fa "struct vfsoptlist *opts" "const char *name" "void **buf" "int *len" .Fc .Ft "char *" .Fn vfs_getopts "struct vfsoptlist *opts" "const char *name" "int *error" .Ft int .Fo vfs_flagopt .Fa "struct vfsoptlist *opts" "const char *name" "uint64_t *flags" "uint64_t flag" .Fc .Ft int .Fo vfs_scanopt .Fa "struct vfsoptlist *opts" "const char *name" "const char *fmt" ... .Fc .Ft int .Fo vfs_copyopt .Fa "struct vfsoptlist *opts" "const char *name" "void *dest" "int len" .Fc .Ft int .Fo vfs_filteropt .Fa "struct vfsoptlist *opts" "const char **legal" .Fc .Ft int .Fo vfs_setopt .Fa "struct vfsoptlist *opts" "const char *name" "void *value" "int len" .Fc .Ft int .Fo vfs_setopt_part .Fa "struct vfsoptlist *opts" "const char *name" "void *value" "int len" .Fc .Ft int .Fo vfs_setopts .Fa "struct vfsoptlist *opts" "const char *name" "const char *value" .Fc .Sh DESCRIPTION The .Fn vfs_getopt function sets .Fa buf to point to the value of the named mount option, and sets .Fa len to the length of the value if it is not .Dv NULL . The .Fa buf argument will point to the actual value, and does not need to be freed or released (and probably should not be modified). .Pp The .Fn vfs_getopts function returns the value of the specified option if it is a string (i.e., .Dv NUL terminated). .Pp The .Fn vfs_flagopt function determines if an option exists. If the option does exist, and .Fa flags is not .Dv NULL , .Fa flag is added to those already set in .Fa flags . If the option does not exist, and .Fa flags is not .Dv NULL , .Fa flag is removed from those already set in .Fa flags . An example of typical usage is: .Bd -literal if (vfs_flagopt(mp->mnt_optnew, "wormlike", NULL, 0)) vfs_flagopt(mp->mnt_optnew, "appendok", &(mp->flags), F_APPENDOK); .Ed .Pp The .Fn vfs_scanopt function performs a .Xr vsscanf 3 with the option's value, using the given format, into the specified variable arguments. The value must be a string (i.e., .Dv NUL terminated). .Pp The .Fn vfs_copyopt function creates a copy of the option's value. The .Fa len argument must match the length of the option's value exactly (i.e., a larger buffer will still cause .Fn vfs_copyout to fail with .Er EINVAL ) . .Pp The .Fn vfs_filteropt function ensures that no unknown options were specified. A option is valid if its name matches one of the names in the list of legal names. An option may be prefixed with 'no', and still be considered valid. .Pp The .Fn vfs_setopt and .Fn vfs_setopt_part functions copy new data into the option's value. In .Fn vfs_setopt , the .Fa len argument must match the length of the option's value exactly (i.e., a larger buffer will still cause .Fn vfs_copyout to fail with .Er EINVAL ) . .Pp The .Fn vfs_setopts function copies a new string into the option's value. The string, including .Dv NUL byte, must be no longer than the option's length. .Sh RETURN VALUES The .Fn vfs_getopt function returns 0 if the option was found; otherwise, .Er ENOENT is returned. .Pp The .Fn vfs_getopts function returns the specified option if it is found, and is .Dv NUL terminated. If the option was found, but is not .Dv NUL terminated, .Fa error is set to .Er EINVAL and .Dv NULL is returned. If the option was not found, .Fa error is set to 0, and .Dv NULL is returned. .Pp The .Fn vfs_flagopt function returns 1 if the option was found, and 0 if it was not. .Pp The .Fn vfs_scanopt function returns 0 if the option was not found, or was not .Dv NUL terminated; otherwise, the return value of .Xr vsscanf 3 is returned. If .Xr vsscanf 3 returns 0, it will be returned unchanged; therefore, a return value of 0 does not always mean the option does not exist, or is not a valid string. .Pp The .Fn vfs_copyopt and .Fn vfs_setopt functions return 0 if the copy was successful, .Er EINVAL if the option was found but the lengths did not match, and .Er ENOENT if the option was not found. .Pp The .Fn vfs_filteropt function returns 0 if all of the options are legal; otherwise, .Er EINVAL is returned. .Pp The .Fn vfs_setopts function returns 0 if the copy was successful, .Er EINVAL if the option was found but the string was too long, and .Er ENOENT if the option was not found. .Sh AUTHORS .An -nosplit This manual page was written by .An Chad David Aq Mt davidc@FreeBSD.org and .An Ruslan Ermilov Aq Mt ru@FreeBSD.org .