Initial Spring 2016 commit.

kern/vfs/vfscwd.c

@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * 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 UNIVERSITY 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 UNIVERSITY 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 operations involving the current directory.
+ */
+
+#include <types.h>
+#include <kern/errno.h>
+#include <stat.h>
+#include <lib.h>
+#include <uio.h>
+#include <proc.h>
+#include <current.h>
+#include <vfs.h>
+#include <fs.h>
+#include <vnode.h>
+
+/*
+ * Get current directory as a vnode.
+ */
+int
+vfs_getcurdir(struct vnode **ret)
+{
+	int rv = 0;
+
+	spinlock_acquire(&curproc->p_lock);
+	if (curproc->p_cwd!=NULL) {
+		VOP_INCREF(curproc->p_cwd);
+		*ret = curproc->p_cwd;
+	}
+	else {
+		rv = ENOENT;
+	}
+	spinlock_release(&curproc->p_lock);
+
+	return rv;
+}
+
+/*
+ * Set current directory as a vnode.
+ * The passed vnode must in fact be a directory.
+ */
+int
+vfs_setcurdir(struct vnode *dir)
+{
+	struct vnode *old;
+	mode_t vtype;
+	int result;
+
+	result = VOP_GETTYPE(dir, &vtype);
+	if (result) {
+		return result;
+	}
+	if (vtype != S_IFDIR) {
+		return ENOTDIR;
+	}
+
+	VOP_INCREF(dir);
+
+	spinlock_acquire(&curproc->p_lock);
+	old = curproc->p_cwd;
+	curproc->p_cwd = dir;
+	spinlock_release(&curproc->p_lock);
+
+	if (old!=NULL) {
+		VOP_DECREF(old);
+	}
+
+	return 0;
+}
+
+/*
+ * Set current directory to "none".
+ */
+int
+vfs_clearcurdir(void)
+{
+	struct vnode *old;
+
+	spinlock_acquire(&curproc->p_lock);
+	old = curproc->p_cwd;
+	curproc->p_cwd = NULL;
+	spinlock_release(&curproc->p_lock);
+
+	if (old!=NULL) {
+		VOP_DECREF(old);
+	}
+
+	return 0;
+}
+
+/*
+ * Set current directory, as a pathname. Use vfs_lookup to translate
+ * it to a vnode.
+ */
+int
+vfs_chdir(char *path)
+{
+	struct vnode *vn;
+	int result;
+
+	result = vfs_lookup(path, &vn);
+	if (result) {
+		return result;
+	}
+	result = vfs_setcurdir(vn);
+	VOP_DECREF(vn);
+	return result;
+}
+
+/*
+ * Get current directory, as a pathname.
+ * Use VOP_NAMEFILE to get the pathname and FSOP_GETVOLNAME to get the
+ * volume name.
+ */
+int
+vfs_getcwd(struct uio *uio)
+{
+	struct vnode *cwd;
+	int result;
+	const char *name;
+	char colon=':';
+
+	KASSERT(uio->uio_rw==UIO_READ);
+
+	result = vfs_getcurdir(&cwd);
+	if (result) {
+		return result;
+	}
+
+	/* The current dir must be a directory, and thus it is not a device. */
+	KASSERT(cwd->vn_fs != NULL);
+
+	name = FSOP_GETVOLNAME(cwd->vn_fs);
+	if (name==NULL) {
+		vfs_biglock_acquire();
+		name = vfs_getdevname(cwd->vn_fs);
+		vfs_biglock_release();
+	}
+	KASSERT(name != NULL);
+
+	result = uiomove((char *)name, strlen(name), uio);
+	if (result) {
+		goto out;
+	}
+	result = uiomove(&colon, 1, uio);
+	if (result) {
+		goto out;
+	}
+
+	result = VOP_NAMEFILE(cwd, uio);
+
+ out:
+
+	VOP_DECREF(cwd);
+	return result;
+}