/* * 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. */ /* * High-level VFS operations on pathnames. */ #include <types.h> #include <kern/errno.h> #include <kern/fcntl.h> #include <limits.h> #include <lib.h> #include <vfs.h> #include <vnode.h> /* Does most of the work for open(). */ int vfs_open(char *path, int openflags, mode_t mode, struct vnode **ret) { int how; int result; int canwrite; struct vnode *vn = NULL; how = openflags & O_ACCMODE; switch (how) { case O_RDONLY: canwrite=0; break; case O_WRONLY: case O_RDWR: canwrite=1; break; default: return EINVAL; } if (openflags & O_CREAT) { char name[NAME_MAX+1]; struct vnode *dir; int excl = (openflags & O_EXCL)!=0; result = vfs_lookparent(path, &dir, name, sizeof(name)); if (result) { return result; } result = VOP_CREAT(dir, name, excl, mode, &vn); VOP_DECREF(dir); } else { result = vfs_lookup(path, &vn); } if (result) { return result; } KASSERT(vn != NULL); result = VOP_EACHOPEN(vn, openflags); if (result) { VOP_DECREF(vn); return result; } if (openflags & O_TRUNC) { if (canwrite==0) { result = EINVAL; } else { result = VOP_TRUNCATE(vn, 0); } if (result) { VOP_DECREF(vn); return result; } } *ret = vn; return 0; } /* Does most of the work for close(). */ void vfs_close(struct vnode *vn) { /* * VOP_DECREF doesn't return an error. * * We assume that the file system makes every reasonable * effort to not fail. If it does fail - such as on a hard I/O * error or something - vnode.c prints a warning. The reason * we don't report errors up to or above this level is that * (1) most application software does not check for close * failing, and more importantly * (2) we're often called from places like process exit * where reporting the error is impossible and * meaningful recovery is entirely impractical. */ VOP_DECREF(vn); } /* Does most of the work for remove(). */ int vfs_remove(char *path) { struct vnode *dir; char name[NAME_MAX+1]; int result; result = vfs_lookparent(path, &dir, name, sizeof(name)); if (result) { return result; } result = VOP_REMOVE(dir, name); VOP_DECREF(dir); return result; } /* Does most of the work for rename(). */ int vfs_rename(char *oldpath, char *newpath) { struct vnode *olddir; char oldname[NAME_MAX+1]; struct vnode *newdir; char newname[NAME_MAX+1]; int result; result = vfs_lookparent(oldpath, &olddir, oldname, sizeof(oldname)); if (result) { return result; } result = vfs_lookparent(newpath, &newdir, newname, sizeof(newname)); if (result) { VOP_DECREF(olddir); return result; } if (olddir->vn_fs==NULL || newdir->vn_fs==NULL || olddir->vn_fs != newdir->vn_fs) { VOP_DECREF(newdir); VOP_DECREF(olddir); return EXDEV; } result = VOP_RENAME(olddir, oldname, newdir, newname); VOP_DECREF(newdir); VOP_DECREF(olddir); return result; } /* Does most of the work for link(). */ int vfs_link(char *oldpath, char *newpath) { struct vnode *oldfile; struct vnode *newdir; char newname[NAME_MAX+1]; int result; result = vfs_lookup(oldpath, &oldfile); if (result) { return result; } result = vfs_lookparent(newpath, &newdir, newname, sizeof(newname)); if (result) { VOP_DECREF(oldfile); return result; } if (oldfile->vn_fs==NULL || newdir->vn_fs==NULL || oldfile->vn_fs != newdir->vn_fs) { VOP_DECREF(newdir); VOP_DECREF(oldfile); return EXDEV; } result = VOP_LINK(newdir, newname, oldfile); VOP_DECREF(newdir); VOP_DECREF(oldfile); return result; } /* * Does most of the work for symlink(). * * Note, however, if you're implementing symlinks, that various * other parts of the VFS layer are missing crucial elements of * support for symlinks. */ int vfs_symlink(const char *contents, char *path) { struct vnode *newdir; char newname[NAME_MAX+1]; int result; result = vfs_lookparent(path, &newdir, newname, sizeof(newname)); if (result) { return result; } result = VOP_SYMLINK(newdir, newname, contents); VOP_DECREF(newdir); return result; } /* * Does most of the work for readlink(). * * Note, however, if you're implementing symlinks, that various * other parts of the VFS layer are missing crucial elements of * support for symlinks. */ int vfs_readlink(char *path, struct uio *uio) { struct vnode *vn; int result; result = vfs_lookup(path, &vn); if (result) { return result; } result = VOP_READLINK(vn, uio); VOP_DECREF(vn); return result; } /* * Does most of the work for mkdir. */ int vfs_mkdir(char *path, mode_t mode) { struct vnode *parent; char name[NAME_MAX+1]; int result; result = vfs_lookparent(path, &parent, name, sizeof(name)); if (result) { return result; } result = VOP_MKDIR(parent, name, mode); VOP_DECREF(parent); return result; } /* * Does most of the work for rmdir. */ int vfs_rmdir(char *path) { struct vnode *parent; char name[NAME_MAX+1]; int result; result = vfs_lookparent(path, &parent, name, sizeof(name)); if (result) { return result; } result = VOP_RMDIR(parent, name); VOP_DECREF(parent); return result; }