NAME¶

SYNOPSIS¶

int
kernel_mount(struct mntarg *ma, int flags);

int
kernel_vmount(int flags, ...);

struct mntarg *
mount_arg(struct mntarg *ma, const char *name, const void *val, int len);

struct mntarg *
mount_argb(struct mntarg *ma, int flag, const char *name);

struct mntarg *
mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...);

struct mntarg *
mount_argsu(struct mntarg *ma, const char *name, const void *val, int len);

DESCRIPTION¶

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 kernel_vmount() is a function similar to printf(9) which is used to mount a file system.

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¶

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);
}

When working with kernel_vmount(), varargs must come in pairs, e.g., {name, value}.

	error = kernel_vmount(
	    MNT_RDONLY,
	    "fstype", vfsname,
	    "fspath", "/",
	    "from", path,
	    NULL);

SEE ALSO¶

HISTORY¶

AUTHORS¶