/* * 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 relating to pathname translation */ #include <types.h> #include <kern/errno.h> #include <limits.h> #include <lib.h> #include <synch.h> #include <vfs.h> #include <fs.h> #include <vnode.h> static struct vnode *bootfs_vnode = NULL; /* * Helper function for actually changing bootfs_vnode. */ static void change_bootfs(struct vnode *newvn) { struct vnode *oldvn; oldvn = bootfs_vnode; bootfs_vnode = newvn; if (oldvn != NULL) { VOP_DECREF(oldvn); } } /* * Set bootfs_vnode. * * Bootfs_vnode is the vnode used for beginning path translation of * pathnames starting with /. * * It is also incidentally the system's first current directory. */ int vfs_setbootfs(const char *fsname) { char tmp[NAME_MAX+1]; char *s; int result; struct vnode *newguy; vfs_biglock_acquire(); snprintf(tmp, sizeof(tmp)-1, "%s", fsname); s = strchr(tmp, ':'); if (s) { /* If there's a colon, it must be at the end */ if (strlen(s)>0) { vfs_biglock_release(); return EINVAL; } } else { strcat(tmp, ":"); } result = vfs_chdir(tmp); if (result) { vfs_biglock_release(); return result; } result = vfs_getcurdir(&newguy); if (result) { vfs_biglock_release(); return result; } change_bootfs(newguy); vfs_biglock_release(); return 0; } /* * Clear the bootfs vnode (preparatory to system shutdown). */ void vfs_clearbootfs(void) { vfs_biglock_acquire(); change_bootfs(NULL); vfs_biglock_release(); } /* * Common code to pull the device name, if any, off the front of a * path and choose the vnode to begin the name lookup relative to. */ static int getdevice(char *path, char **subpath, struct vnode **startvn) { int slash=-1, colon=-1, i; struct vnode *vn; int result; KASSERT(vfs_biglock_do_i_hold()); /* * Locate the first colon or slash. */ for (i=0; path[i]; i++) { if (path[i]==':') { colon = i; break; } if (path[i]=='/') { slash = i; break; } } if (colon < 0 && slash != 0) { /* * No colon before a slash, so no device name * specified, and the slash isn't leading or is also * absent, so this is a relative path or just a bare * filename. Start from the current directory, and * use the whole thing as the subpath. */ *subpath = path; return vfs_getcurdir(startvn); } if (colon>0) { /* device:path - get root of device's filesystem */ path[colon]=0; while (path[colon+1]=='/') { /* device:/path - skip slash, treat as device:path */ colon++; } *subpath = &path[colon+1]; result = vfs_getroot(path, startvn); if (result) { return result; } return 0; } /* * We have either /path or :path. * * /path is a path relative to the root of the "boot filesystem". * :path is a path relative to the root of the current filesystem. */ KASSERT(colon==0 || slash==0); if (path[0]=='/') { if (bootfs_vnode==NULL) { return ENOENT; } VOP_INCREF(bootfs_vnode); *startvn = bootfs_vnode; } else { KASSERT(path[0]==':'); result = vfs_getcurdir(&vn); if (result) { return result; } /* * The current directory may not be a device, so it * must have a fs. */ KASSERT(vn->vn_fs!=NULL); *startvn = FSOP_GETROOT(vn->vn_fs); VOP_DECREF(vn); } while (path[1]=='/') { /* ///... or :/... */ path++; } *subpath = path+1; return 0; } /* * Name-to-vnode translation. * (In BSD, both of these are subsumed by namei().) */ int vfs_lookparent(char *path, struct vnode **retval, char *buf, size_t buflen) { struct vnode *startvn; int result; vfs_biglock_acquire(); result = getdevice(path, &path, &startvn); if (result) { vfs_biglock_release(); return result; } if (strlen(path)==0) { /* * It does not make sense to use just a device name in * a context where "lookparent" is the desired * operation. */ result = EINVAL; } else { result = VOP_LOOKPARENT(startvn, path, retval, buf, buflen); } VOP_DECREF(startvn); vfs_biglock_release(); return result; } int vfs_lookup(char *path, struct vnode **retval) { struct vnode *startvn; int result; vfs_biglock_acquire(); result = getdevice(path, &path, &startvn); if (result) { vfs_biglock_release(); return result; } if (strlen(path)==0) { *retval = startvn; vfs_biglock_release(); return 0; } result = VOP_LOOKUP(startvn, path, retval); VOP_DECREF(startvn); vfs_biglock_release(); return result; }