/* $NetBSD: vfs_init.c,v 1.68 2026/03/27 23:43:13 yamt Exp $ */ /*- * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, * NASA Ames Research Center. * * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed * to Berkeley by John Heidemann of the UCLA Ficus project. * * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)vfs_init.c 8.5 (Berkeley) 5/11/95 */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: vfs_init.c,v 1.68 2026/03/27 23:43:13 yamt Exp $"); #include <sys/param.h> #include <sys/types.h> #include <sys/buf.h> #include <sys/dirhash.h> #include <sys/errno.h> #include <sys/kauth.h> #include <sys/kmem.h> #include <sys/module.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/sdt.h> #include <sys/stat.h> #include <sys/sysctl.h> #include <sys/systm.h> #include <sys/time.h> #include <sys/ucred.h> #include <sys/vnode.h> #include <sys/vnode_impl.h> #include <miscfs/deadfs/deadfs.h> #include <miscfs/fifofs/fifo.h> #include <miscfs/specfs/specdev.h> /* * Sigh, such primitive tools are these... */ #if 0 #define DODEBUG(A) A #else #define DODEBUG(A) __nothing #endif SDT_PROVIDER_DEFINE(vfs); /* * These vnodeopv_descs are listed here because they are not * associated with any particular file system, and thus cannot * be initialized by vfs_attach(). */ const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = { &dead_vnodeop_opv_desc, &fifo_vnodeop_opv_desc, &spec_vnodeop_opv_desc, NULL, }; struct vfs_list_head vfs_list = /* vfs list */ LIST_HEAD_INITIALIZER(vfs_list); static kauth_listener_t mount_listener; /* * This code doesn't work if the defn is **vnodop_defns with cc. * The problem is because of the compiler sometimes putting in an * extra level of indirection for arrays. It's an interesting * "feature" of C. */ typedef int (*PFI)(void *); /* * A miscellaneous routine. * A generic "default" routine that just returns an error. */ /*ARGSUSED*/ int vn_default_error(void *v) { return SET_ERROR(EOPNOTSUPP); } static struct sysctllog *vfs_sysctllog; /* * Top level filesystem related information gathering. */ static void sysctl_vfs_setup(void) { sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "generic", SYSCTL_DESCR("Non-specific vfs related information"), NULL, 0, NULL, 0, CTL_VFS, VFS_GENERIC, CTL_EOL); sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRING, "fstypes", SYSCTL_DESCR("List of file systems present"), sysctl_vfs_generic_fstypes, 0, NULL, 0, CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL); sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "magiclinks", SYSCTL_DESCR("Whether \"magic\" symlinks are expanded"), NULL, 0, &vfs_magiclinks, 0, CTL_VFS, VFS_GENERIC, VFS_MAGICLINKS, CTL_EOL); sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "timestamp_precision", SYSCTL_DESCR("File timestamp precision"), NULL, 0, &vfs_timestamp_precision, 0, CTL_VFS, VFS_GENERIC, VFS_TIMESTAMP_PRECISION, CTL_EOL); } /* * vfs_init.c * * Allocate and fill in operations vectors. * * An undocumented feature of this approach to defining operations is that * there can be multiple entries in vfs_opv_descs for the same operations * vector. This allows third parties to extend the set of operations * supported by another layer in a binary compatibile way. For example, * assume that NFS needed to be modified to support Ficus. NFS has an entry * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) * listing those new operations Ficus adds to NFS, all without modifying the * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but * that is a(whole)nother story.) This is a feature. */ /* * Init the vector, if it needs it. * Also handle backwards compatibility. */ static void vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc) { int (**opv_desc_vector)(void *); const struct vnodeopv_entry_desc *opve_descp; opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); for (opve_descp = vfs_opv_desc->opv_desc_ops; opve_descp->opve_op; opve_descp++) { /* * Sanity check: is this operation listed * in the list of operations? We check this * by seeing if its offset is zero. Since * the default routine should always be listed * first, it should be the only one with a zero * offset. Any other operation with a zero * offset is probably not listed in * vfs_op_descs, and so is probably an error. * * A panic here means the layer programmer * has committed the all-too common bug * of adding a new operation to the layer's * list of vnode operations but * not adding the operation to the system-wide * list of supported operations. */ if (opve_descp->opve_op->vdesc_offset == 0 && opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) { printf("operation %s not listed in %s.\n", opve_descp->opve_op->vdesc_name, "vfs_op_descs"); panic("vfs_opv_init: bad operation"); } /* * Fill in this entry. */ opv_desc_vector[opve_descp->opve_op->vdesc_offset] = opve_descp->opve_impl; } } static void vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc) { int j; int (**opv_desc_vector)(void *); opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); /* * Force every operations vector to have a default routine. */ if (opv_desc_vector[VOFFSET(vop_default)] == NULL) panic("vfs_opv_init: operation vector without vop_default"); for (j = 0; j < VNODE_OPS_COUNT; j++) { if (opv_desc_vector[j] == NULL) { opv_desc_vector[j] = opv_desc_vector[VOFFSET(vop_default)]; } } } void vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp) { int (**opv_desc_vector)(void *); int i; /* * Allocate the vectors. */ for (i = 0; vopvdpp[i] != NULL; i++) { opv_desc_vector = kmem_alloc(VNODE_OPS_COUNT * sizeof(PFI), KM_SLEEP); memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI)); *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector; DODEBUG(printf("vector at %p allocated\n", opv_desc_vector_p)); } /* * ...and fill them in. */ for (i = 0; vopvdpp[i] != NULL; i++) vfs_opv_init_explicit(vopvdpp[i]); /* * Finally, go back and replace unfilled routines * with their default. */ for (i = 0; vopvdpp[i] != NULL; i++) vfs_opv_init_default(vopvdpp[i]); } void vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp) { int i; /* * Free the vectors allocated in vfs_opv_init(). */ for (i = 0; vopvdpp[i] != NULL; i++) { kmem_free(*(vopvdpp[i]->opv_desc_vector_p), VNODE_OPS_COUNT * sizeof(PFI)); *(vopvdpp[i]->opv_desc_vector_p) = NULL; } } #ifdef DEBUG static void vfs_op_check(void) { int i; DODEBUG(printf("Vnode_interface_init.\n")); /* * Check offset of each op. */ for (i = 0; vfs_op_descs[i]; i++) { if (vfs_op_descs[i]->vdesc_offset != i) panic("vfs_op_check: vfs_op_desc[] offset mismatch"); } if (i != VNODE_OPS_COUNT) { panic("vfs_op_check: vnode ops count mismatch (%d != %d)", i, VNODE_OPS_COUNT); } DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT)); } #endif /* DEBUG */ /* * Common routine to check if an unprivileged mount is allowed. * * We export just this part (i.e., without the access control) so that if a * secmodel wants to implement finer grained user mounts it can do so without * copying too much code. More elaborate policies (i.e., specific users allowed * to also create devices and/or introduce set-id binaries, or export * file-systems) will require a different implementation. * * This routine is intended to be called from listener context, and as such * does not take credentials as an argument. */ int usermount_common_policy(struct mount *mp, u_long flags) { /* No exporting if unprivileged. */ if (flags & MNT_EXPORTED) return SET_ERROR(EPERM); /* Must have 'nosuid' and 'nodev'. */ if ((flags & MNT_NODEV) == 0 || (flags & MNT_NOSUID) == 0) return SET_ERROR(EPERM); /* Retain 'noexec'. */ if ((mp->mnt_flag & MNT_NOEXEC) && (flags & MNT_NOEXEC) == 0) return SET_ERROR(EPERM); return 0; } static int mount_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, void *arg0, void *arg1, void *arg2, void *arg3) { int result; enum kauth_system_req req; result = KAUTH_RESULT_DEFER; req = (enum kauth_system_req)(uintptr_t)(uintptr_t)arg0; if (action != KAUTH_SYSTEM_MOUNT) return result; if (req == KAUTH_REQ_SYSTEM_MOUNT_GET) result = KAUTH_RESULT_ALLOW; else if (req == KAUTH_REQ_SYSTEM_MOUNT_DEVICE) { vnode_t *devvp = arg2; accmode_t accmode = (accmode_t)(unsigned long)arg3; int error; error = VOP_ACCESS(devvp, accmode, cred); if (!error) result = KAUTH_RESULT_ALLOW; } return result; } /* * Initialize the vnode structures and initialize each file system type. */ void vfsinit(void) { /* * Attach sysctl nodes */ sysctl_vfs_setup(); /* * Initialize the vnode table */ vntblinit(); /* * Initialize the vnode name cache */ nchinit(); #ifdef DEBUG /* * Check the list of vnode operations. */ vfs_op_check(); #endif /* * Initialize the special vnode operations. */ vfs_opv_init(vfs_special_vnodeopv_descs); /* * Initialise generic dirhash. */ dirhash_init(); /* * Initialise VFS hooks. */ vfs_hooks_init(); mount_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, mount_listener_cb, NULL); /* * Establish each file system which was statically * included in the kernel. */ module_init_class(MODULE_CLASS_VFS); /* * Initialize EVFILT_FS for kqueue. */ vfs_evfilt_fs_init(); } /* * Drop a reference to a file system type. */ void vfs_delref(struct vfsops *vfs) { mutex_enter(&vfs_list_lock); vfs->vfs_refcount--; mutex_exit(&vfs_list_lock); } /* * Establish a file system and initialize it. */ int vfs_attach(struct vfsops *vfs) { struct vfsops *v; int error = 0; mutex_enter(&vfs_list_lock); /* * Make sure this file system doesn't already exist. */ LIST_FOREACH(v, &vfs_list, vfs_list) { long fstype; if (strcmp(vfs->vfs_name, v->vfs_name) == 0) { error = SET_ERROR(EEXIST); goto out; } fstype = makefstype(vfs->vfs_name); if (fstype == makefstype(v->vfs_name)) { printf("failed to attach file system '%s' " "because it shares the same fstype (%ld) " "with %s\n", vfs->vfs_name, fstype, v->vfs_name); error = SET_ERROR(EEXIST); goto out; } } /* * Initialize the vnode operations for this file system. */ vfs_opv_init(vfs->vfs_opv_descs); /* * Now initialize the file system itself. */ (*vfs->vfs_init)(); /* * ...and link it into the kernel's list. */ LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list); /* * Sanity: make sure the reference count is 0. */ vfs->vfs_refcount = 0; out: mutex_exit(&vfs_list_lock); return error; } /* * Remove a file system from the kernel. */ int vfs_detach(struct vfsops *vfs) { struct vfsops *v; int error = 0; mutex_enter(&vfs_list_lock); /* * Make sure no one is using the filesystem. */ if (vfs->vfs_refcount != 0) { error = SET_ERROR(EBUSY); goto out; } /* * ...and remove it from the kernel's list. */ LIST_FOREACH(v, &vfs_list, vfs_list) { if (v == vfs) { LIST_REMOVE(v, vfs_list); break; } } if (v == NULL) { error = SET_ERROR(ESRCH); goto out; } /* * Now run the file system-specific cleanups. */ (*vfs->vfs_done)(); /* * Free the vnode operations vector. */ vfs_opv_free(vfs->vfs_opv_descs); out: mutex_exit(&vfs_list_lock); return error; } void vfs_reinit(void) { struct vfsops *vfs; mutex_enter(&vfs_list_lock); LIST_FOREACH(vfs, &vfs_list, vfs_list) { if (vfs->vfs_reinit) { vfs->vfs_refcount++; mutex_exit(&vfs_list_lock); (*vfs->vfs_reinit)(); mutex_enter(&vfs_list_lock); vfs->vfs_refcount--; } } mutex_exit(&vfs_list_lock); }
