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diff --git a/share/man/man9/kernel_mount.9 b/share/man/man9/kernel_mount.9 new file mode 100644 index 0000000..10fb353 --- /dev/null +++ b/share/man/man9/kernel_mount.9 @@ -0,0 +1,211 @@ +.\" +.\" Copyright (c) 2004 Tom Rhodes +.\" 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. +.\" +.\" $FreeBSD$ +.\" +.Dd December 13, 2004 +.Dt KERNEL_MOUNT 9 +.Os +.Sh NAME +.Nm free_mntarg , +.Nm kernel_mount , +.Nm kernel_vmount , +.Nm mount_arg , +.Nm mount_argb , +.Nm mount_argf , +.Nm mount_argsu +.Nd "functions provided as part of the kernel mount interface" +.Sh SYNOPSIS +.Ft void +.Fn free_mntarg "struct mntarg *ma" +.Ft int +.Fn kernel_mount "struct mntarg *ma" "int flags" +.Ft int +.Fn kernel_vmount "int flags" ... +.Ft "struct mntarg *" +.Fo mount_arg +.Fa "struct mntarg *ma" "const char *name" "const void *val" "int len" +.Fc +.Ft "struct mntarg *" +.Fn mount_argb "struct mntarg *ma" "int flag" "const char *name" +.Ft "struct mntarg *" +.Fn mount_argf "struct mntarg *ma" "const char *name" "const char *fmt" ... +.Ft "struct mntarg *" +.Fo mount_argsu +.Fa "struct mntarg *ma" "const char *name" "const void *val" "int len" +.Fc +.Sh DESCRIPTION +The +.Fn kernel_mount +family of functions are provided as an API for building a list +of mount arguments which will be used to mount file systems +from inside the kernel. +By accumulating a list of arguments, the API takes shape and +provides the information necessary for the kernel to control +the +.Xr mount 8 +utility. +When an error occurs, the process will stop. +This will not cause a +.Xr panic 9 . +.Pp +The header of the structure is stored in +.Pa src/sys/kern/vfs_mount.c +which permits automatic structure creation to +ease the mount process. +Memory allocation must always be freed when the entire +process is complete, it is an error otherwise. +.Pp +The +.Fn free_mntarg +function is used to free or clear the +.Vt mntarg +structure. +.Pp +The +.Fn kernel_mount +function pulls information from the structure to perform +the mount request on a given file system. +Additionally, the +.Fn kernel_mount +function always calls the +.Fn free_mntarg +function. +If +.Fa ma +contains any error code generated during the construction, +that code will be called and the file system mount will +not be attempted. +.Pp +The +.Fn kernel_vmount +is a function similar to +.Xr printf 9 +which is used to mount a file system. +.Pp +The +.Fn mount_arg +function takes a plain argument and crafts parts of +the structure with regards to various mount options. +If the length is a value less than 0, +.Xr strlen 3 +is used. +This argument will be referenced until either +.Fn free_mntarg +or +.Fn kernel_mount +is called. +.Pp +The +.Fn mount_argb +function is used to add boolean arguments to +the structure. +The +.Fa flag +is the boolean value and +.Fa name +must start with +.Qq Li no , +otherwise a panic will occur. +.Pp +The +.Fn mount_argf +function adds +.Xr printf 9 +style arguments to the current structure. +.Pp +The +.Fn mount_argsu +function will add arguments to the structure from a +userland string. +.Sh EXAMPLES +An example of the +.Fn *_cmount +function: +.Bd -literal +static int +msdosfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td) +{ + struct msdosfs_args args; + int error; + + if (data == NULL) + return (EINVAL); + error = copyin(data, &args, sizeof(args)); + if (error) + return (error); + + ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN); + ma = mount_arg(ma, "export", &args.export, sizeof(args.export)); + ma = mount_argf(ma, "uid", "%d", args.uid); + ma = mount_argf(ma, "gid", "%d", args.gid); + ma = mount_argf(ma, "mask", "%d", args.mask); + ma = mount_argf(ma, "dirmask", "%d", args.dirmask); + + ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname"); + ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname"); + ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95"); + ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv"); + + ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN); + ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN); + ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN); + + error = kernel_mount(ma, flags); + + return (error); +} +.Ed +.Pp +When working with +.Fn kernel_vmount , +.Fa varargs +must come in pairs, e.g., +.Brq Va name , value . +.Bd -literal + error = kernel_vmount( + MNT_RDONLY, + "fstype", vfsname, + "fspath", "/", + "from", path, + NULL); +.Ed +.Sh SEE ALSO +.Xr VFS 9 , +.Xr VFS_MOUNT 9 , +.Sh HISTORY +The +.Fn kernel_mount +family of functions and this manual page first +appeared in +.Fx 6.0 . +.Sh AUTHORS +.An -nosplit +The +.Fn kernel_mount +family of functions and API was developed by +.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org . +This manual page was written by +.An Tom Rhodes Aq Mt trhodes@FreeBSD.org . |
