mount_argf9
Functions provided as part of the kernel mount interface
Part of free_mntarg(9).
Usage
void
int
struct mntarg
*
struct mntarg
*
struct mntarg
*
struct mntarg
*
Overview
The 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 mount(8) utility. When an error occurs, the process will stop. This will not cause a panic(9).
The header of the structure is stored in 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.
The free_mntarg() function is used to free or clear the mntarg structure.
The kernel_mount() function pulls information from the structure to perform the mount request on a given file system. Additionally, the kernel_mount() function always calls the free_mntarg() function. If ma contains any error code generated during the construction, that code will be called and the file system mount will not be attempted.
The 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, strlen(3) is used. This argument will be referenced until either free_mntarg() or kernel_mount() is called.
The mount_argb() function is used to add boolean arguments to the structure. The flag is the boolean value and name must start with "no", otherwise a panic will occur.
The mount_argf() function adds printf(9) style arguments to the current structure.
The mount_argsu() function will add arguments to the structure from a userland string.
Examples
An example of the *_cmount() function:
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);
}
History
- FreeBSD 16.0-CURRENT (2026-10-27) to FreeBSD 14.0-RELEASE: the text shown here
- FreeBSD 13.5-RELEASE to FreeBSD 13.3-RELEASE
- FreeBSD 13.2-RELEASE to FreeBSD 13.0-RELEASE
- FreeBSD 12.4-RELEASE
- FreeBSD 12.3-RELEASE
- FreeBSD 12.2-RELEASE
- FreeBSD 12.1-RELEASE
- FreeBSD 12.0-RELEASE
- FreeBSD 11.4-RELEASE
- FreeBSD 11.3-RELEASE
- FreeBSD 11.2-RELEASE
- FreeBSD 11.1-RELEASE
- FreeBSD 11.0-RELEASE
- FreeBSD 10.4-RELEASE
- FreeBSD 10.3-RELEASE
- FreeBSD 10.2-RELEASE
- FreeBSD 10.1-RELEASE
- FreeBSD 10.0-RELEASE
- FreeBSD 9.3-RELEASE
- FreeBSD 9.2-RELEASE
- FreeBSD 9.1-RELEASE
- FreeBSD 9.0-RELEASE
- FreeBSD 8.4-RELEASE
- FreeBSD 8.3-RELEASE
- FreeBSD 8.2-RELEASE
- FreeBSD 8.1-RELEASE
- FreeBSD 8.0-RELEASE
- FreeBSD 7.4-RELEASE
- FreeBSD 7.3-RELEASE
- FreeBSD 7.2-RELEASE
- FreeBSD 7.1-RELEASE
- FreeBSD 7.0-RELEASE
- FreeBSD 6.4-RELEASE
- FreeBSD 6.3-RELEASE to FreeBSD 6.0-RELEASE