BSD 4.4 Lite Kernel Sources

1 files changed, 246 insertions, 0 deletions

diff --git a/sys/kern/vfs_init.c b/sys/kern/vfs_init.c
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+/*
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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	8.3 (Berkeley) 1/4/94
+ */
+
+
+#include <sys/param.h>
+#include <sys/mount.h>
+#include <sys/time.h>
+#include <sys/vnode.h>
+#include <sys/stat.h>
+#include <sys/namei.h>
+#include <sys/ucred.h>
+#include <sys/buf.h>
+#include <sys/errno.h>
+#include <sys/malloc.h>
+
+/*
+ * Sigh, such primitive tools are these...
+ */
+#if 0
+#define DODEBUG(A) A
+#else
+#define DODEBUG(A)
+#endif
+
+extern struct vnodeopv_desc *vfs_opv_descs[];
+				/* a list of lists of vnodeops defns */
+extern struct vnodeop_desc *vfs_op_descs[];
+				/* and the operations they perform */
+/*
+ * 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.
+ */
+int vfs_opv_numops;
+
+typedef (*PFI)();   /* the standard Pointer to a Function returning an Int */
+
+/*
+ * A miscellaneous routine.
+ * A generic "default" routine that just returns an error.
+ */
+int
+vn_default_error()
+{
+
+	return (EOPNOTSUPP);
+}
+
+/*
+ * 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.
+ */
+void
+vfs_opv_init()
+{
+	int i, j, k;
+	int (***opv_desc_vector_p)();
+	int (**opv_desc_vector)();
+	struct vnodeopv_entry_desc *opve_descp;
+
+	/*
+	 * Allocate the dynamic vectors and fill them in.
+	 */
+	for (i=0; vfs_opv_descs[i]; i++) {
+		opv_desc_vector_p = vfs_opv_descs[i]->opv_desc_vector_p;
+		/*
+		 * Allocate and init the vector, if it needs it.
+		 * Also handle backwards compatibility.
+		 */
+		if (*opv_desc_vector_p == NULL) {
+			/* XXX - shouldn't be M_VNODE */
+			MALLOC(*opv_desc_vector_p, PFI*,
+			       vfs_opv_numops*sizeof(PFI), M_VNODE, M_WAITOK);
+			bzero (*opv_desc_vector_p, vfs_opv_numops*sizeof(PFI));
+			DODEBUG(printf("vector at %x allocated\n",
+			    opv_desc_vector_p));
+		}
+		opv_desc_vector = *opv_desc_vector_p;
+		for (j=0; vfs_opv_descs[i]->opv_desc_ops[j].opve_op; j++) {
+			opve_descp = &(vfs_opv_descs[i]->opv_desc_ops[j]);
+
+			/*
+			 * Sanity check:  is this operation listed
+			 * in the list of operations?  We check this
+			 * by seeing if its offest 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;
+		}
+	}
+	/*
+	 * Finally, go back and replace unfilled routines
+	 * with their default.  (Sigh, an O(n^3) algorithm.  I
+	 * could make it better, but that'd be work, and n is small.)
+	 */
+	for (i = 0; vfs_opv_descs[i]; i++) {
+		opv_desc_vector = *(vfs_opv_descs[i]->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 default routine.");
+		}
+		for (k = 0; k<vfs_opv_numops; k++)
+			if (opv_desc_vector[k] == NULL)
+				opv_desc_vector[k] = 
+					opv_desc_vector[VOFFSET(vop_default)];
+	}
+}
+
+/*
+ * Initialize known vnode operations vectors.
+ */
+void
+vfs_op_init()
+{
+	int i;
+
+	DODEBUG(printf("Vnode_interface_init.\n"));
+	/*
+	 * Set all vnode vectors to a well known value.
+	 */
+	for (i = 0; vfs_opv_descs[i]; i++)
+		*(vfs_opv_descs[i]->opv_desc_vector_p) = NULL;
+	/*
+	 * Figure out how many ops there are by counting the table,
+	 * and assign each its offset.
+	 */
+	for (vfs_opv_numops = 0, i = 0; vfs_op_descs[i]; i++) {
+		vfs_op_descs[i]->vdesc_offset = vfs_opv_numops;
+		vfs_opv_numops++;
+	}
+	DODEBUG(printf ("vfs_opv_numops=%d\n", vfs_opv_numops));
+}
+
+/*
+ * Routines having to do with the management of the vnode table.
+ */
+extern struct vnodeops dead_vnodeops;
+extern struct vnodeops spec_vnodeops;
+extern void vclean();
+struct vattr va_null;
+
+/*
+ * Initialize the vnode structures and initialize each file system type.
+ */
+vfsinit()
+{
+	struct vfsops **vfsp;
+
+	/*
+	 * Initialize the vnode table
+	 */
+	vntblinit();
+	/*
+	 * Initialize the vnode name cache
+	 */
+	nchinit();
+	/*
+	 * Build vnode operation vectors.
+	 */
+	vfs_op_init();
+	vfs_opv_init();   /* finish the job */
+	/*
+	 * Initialize each file system type.
+	 */
+	vattr_null(&va_null);
+	for (vfsp = &vfssw[0]; vfsp <= &vfssw[MOUNT_MAXTYPE]; vfsp++) {
+		if (*vfsp == NULL)
+			continue;
+		(*(*vfsp)->vfs_init)();
+	}
+}