static int
devfs_symlink(struct vnop_symlink_args *ap)
/*struct vnop_symlink_args {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vnode_attr *a_vap;
char *a_target;
vfs_context_t a_context;
} */
{
int error;
devdirent_t *newent;
DEVFS_LOCK();
error = devfs_make_symlink(VTODN(ap->a_dvp), ap->a_cnp->cn_nameptr, ap->a_vap->va_mode, ap->a_target, &newent);
if (error == 0) {
error = devfs_dntovn(newent->de_dnp, ap->a_vpp, vfs_context_proc(ap->a_context));
}
DEVFS_UNLOCK();
return error;
}
/*
* Mknod vnode call
*/
static int
devfs_mknod(struct vnop_mknod_args *ap)
/* struct vnop_mknod_args {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vnode_attr *a_vap;
vfs_context_t a_context;
} */
{
struct componentname * cnp = ap->a_cnp;
vfs_context_t ctx = cnp->cn_context;
struct proc *p = vfs_context_proc(ctx);
devnode_t * dev_p;
devdirent_t * devent;
devnode_t * dir_p; /* devnode for parent directory */
struct vnode * dvp = ap->a_dvp;
int error = 0;
devnode_type_t typeinfo;
struct vnode_attr * vap = ap->a_vap;
struct vnode ** vpp = ap->a_vpp;
*vpp = NULL;
if (!(vap->va_type == VBLK) && !(vap->va_type == VCHR)) {
return (EINVAL); /* only support mknod of special files */
}
typeinfo.dev = vap->va_rdev;
DEVFS_LOCK();
dir_p = VTODN(dvp);
error = dev_add_entry(cnp->cn_nameptr, dir_p,
(vap->va_type == VBLK) ? DEV_BDEV : DEV_CDEV,
&typeinfo, NULL, NULL, &devent);
if (error) {
goto failure;
}
dev_p = devent->de_dnp;
error = devfs_dntovn(dev_p, vpp, p);
if (error)
goto failure;
dev_p->dn_uid = vap->va_uid;
dev_p->dn_gid = vap->va_gid;
dev_p->dn_mode = vap->va_mode;
VATTR_SET_SUPPORTED(vap, va_uid);
VATTR_SET_SUPPORTED(vap, va_gid);
VATTR_SET_SUPPORTED(vap, va_mode);
failure:
DEVFS_UNLOCK();
return (error);
}
/* return the address of the root vnode in *vpp */
static int
devfs_root(struct mount *mp, struct vnode **vpp, __unused vfs_context_t ctx)
{
struct devfsmount *devfs_mp_p = (struct devfsmount *)(mp->mnt_data);
int error;
DEVFS_LOCK();
/* last parameter to devfs_dntovn() is ignored */
error = devfs_dntovn(devfs_mp_p->plane_root->de_dnp, vpp, NULL);
DEVFS_UNLOCK();
return error;
}
static int
devfs_symlink(struct vnop_symlink_args *ap)
/*struct vnop_symlink_args {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vnode_attr *a_vap;
char *a_target;
vfs_context_t a_context;
} */
{
struct componentname * cnp = ap->a_cnp;
vfs_context_t ctx = cnp->cn_context;
struct proc *p = vfs_context_proc(ctx);
int error = 0;
devnode_t * dir_p;
devnode_type_t typeinfo;
devdirent_t * nm_p;
devnode_t * dev_p;
struct vnode_attr * vap = ap->a_vap;
struct vnode * * vpp = ap->a_vpp;
typeinfo.Slnk.name = ap->a_target;
typeinfo.Slnk.namelen = strlen(ap->a_target);
DEVFS_LOCK();
dir_p = VTODN(ap->a_dvp);
error = dev_add_entry(cnp->cn_nameptr, dir_p, DEV_SLNK,
&typeinfo, NULL, NULL, &nm_p);
if (error) {
goto failure;
}
dev_p = nm_p->de_dnp;
dev_p->dn_uid = dir_p->dn_uid;
dev_p->dn_gid = dir_p->dn_gid;
dev_p->dn_mode = vap->va_mode;
dn_copy_times(dev_p, dir_p);
error = devfs_dntovn(dev_p, vpp, p);
failure:
DEVFS_UNLOCK();
return error;
}
static int
devfs_mkdir(struct vnop_mkdir_args *ap)
/*struct vnop_mkdir_args {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
struct vnode_attr *a_vap;
vfs_context_t a_context;
} */
{
struct componentname * cnp = ap->a_cnp;
vfs_context_t ctx = cnp->cn_context;
struct proc *p = vfs_context_proc(ctx);
int error = 0;
devnode_t * dir_p;
devdirent_t * nm_p;
devnode_t * dev_p;
struct vnode_attr * vap = ap->a_vap;
struct vnode * * vpp = ap->a_vpp;
DEVFS_LOCK();
dir_p = VTODN(ap->a_dvp);
error = dev_add_entry(cnp->cn_nameptr, dir_p, DEV_DIR,
NULL, NULL, NULL, &nm_p);
if (error) {
goto failure;
}
dev_p = nm_p->de_dnp;
dev_p->dn_uid = dir_p->dn_uid;
dev_p->dn_gid = dir_p->dn_gid;
dev_p->dn_mode = vap->va_mode;
dn_copy_times(dev_p, dir_p);
error = devfs_dntovn(dev_p, vpp, p);
failure:
DEVFS_UNLOCK();
return error;
}
/*
* Convert a component of a pathname into a pointer to a locked node.
* This is a very central and rather complicated routine.
* If the file system is not maintained in a strict tree hierarchy,
* this can result in a deadlock situation (see comments in code below).
*
* The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
* whether the name is to be looked up, created, renamed, or deleted.
* When CREATE, RENAME, or DELETE is specified, information usable in
* creating, renaming, or deleting a directory entry may be calculated.
* If flag has LOCKPARENT or'ed into it and the target of the pathname
* exists, lookup returns both the target and its parent directory locked.
* When creating or renaming and LOCKPARENT is specified, the target may
* not be ".". When deleting and LOCKPARENT is specified, the target may
* be "."., but the caller must check to ensure it does an vrele and DNUNLOCK
* instead of two DNUNLOCKs.
*
* Overall outline of devfs_lookup:
*
* check accessibility of directory
* null terminate the component (lookup leaves the whole string alone)
* look for name in cache, if found, then if at end of path
* and deleting or creating, drop it, else return name
* search for name in directory, to found or notfound
* notfound:
* if creating, return locked directory,
* else return error
* found:
* if at end of path and deleting, return information to allow delete
* if at end of path and rewriting (RENAME and LOCKPARENT), lock target
* node and return info to allow rewrite
* if not at end, add name to cache; if at end and neither creating
* nor deleting, add name to cache
* On return to lookup, remove the null termination we put in at the start.
*
* NOTE: (LOOKUP | LOCKPARENT) currently returns the parent node unlocked.
*/
static int
devfs_lookup(struct vnop_lookup_args *ap)
/*struct vnop_lookup_args {
struct vnode * a_dvp; directory vnode ptr
struct vnode ** a_vpp; where to put the result
struct componentname * a_cnp; the name we want
vfs_context_t a_context;
};*/
{
struct componentname *cnp = ap->a_cnp;
vfs_context_t ctx = cnp->cn_context;
struct proc *p = vfs_context_proc(ctx);
struct vnode *dir_vnode = ap->a_dvp;
struct vnode **result_vnode = ap->a_vpp;
devnode_t * dir_node; /* the directory we are searching */
devnode_t * node = NULL; /* the node we are searching for */
devdirent_t * nodename;
int flags = cnp->cn_flags;
int op = cnp->cn_nameiop; /* LOOKUP, CREATE, RENAME, or DELETE */
int wantparent = flags & (LOCKPARENT|WANTPARENT);
int error = 0;
char heldchar; /* the char at the end of the name componet */
retry:
*result_vnode = NULL; /* safe not sorry */ /*XXX*/
/* okay to look at directory vnodes ourside devfs lock as they are not aliased */
dir_node = VTODN(dir_vnode);
/*
* Make sure that our node is a directory as well.
*/
if (dir_node->dn_type != DEV_DIR) {
return (ENOTDIR);
}
DEVFS_LOCK();
/*
* temporarily terminate string component
*/
heldchar = cnp->cn_nameptr[cnp->cn_namelen];
cnp->cn_nameptr[cnp->cn_namelen] = '\0';
nodename = dev_findname(dir_node, cnp->cn_nameptr);
/*
* restore saved character
*/
cnp->cn_nameptr[cnp->cn_namelen] = heldchar;
if (nodename) {
/* entry exists */
node = nodename->de_dnp;
/* Do potential vnode allocation here inside the lock
* to make sure that our device node has a non-NULL dn_vn
* associated with it. The device node might otherwise
* get deleted out from under us (see devfs_dn_free()).
*/
error = devfs_dntovn(node, result_vnode, p);
}
DEVFS_UNLOCK();
if (error) {
if (error == EAGAIN)
goto retry;
return error;
}
if (!nodename) {
/*
* we haven't called devfs_dntovn if we get here
* we have not taken a reference on the node.. no
* vnode_put is necessary on these error returns
*
* If it doesn't exist and we're not the last component,
* or we're at the last component, but we're not creating
* or renaming, return ENOENT.
*/
if (!(flags & ISLASTCN) || !(op == CREATE || op == RENAME)) {
return ENOENT;
}
/*
* We return with the directory locked, so that
* the parameters we set up above will still be
* valid if we actually decide to add a new entry.
* We return ni_vp == NULL to indicate that the entry
* does not currently exist; we leave a pointer to
* the (locked) directory vnode in namei_data->ni_dvp.
*
* NB - if the directory is unlocked, then this
* information cannot be used.
*/
return (EJUSTRETURN);
}
/*
* from this point forward, we need to vnode_put the reference
* picked up in devfs_dntovn if we decide to return an error
*/
/*
* If deleting, and at end of pathname, return
* parameters which can be used to remove file.
* If the wantparent flag isn't set, we return only
* the directory (in namei_data->ni_dvp), otherwise we go
* on and lock the node, being careful with ".".
*/
if (op == DELETE && (flags & ISLASTCN)) {
/*
* we are trying to delete '.'. What does this mean? XXX
*/
if (dir_node == node) {
if (*result_vnode) {
vnode_put(*result_vnode);
*result_vnode = NULL;
}
if ( ((error = vnode_get(dir_vnode)) == 0) ) {
*result_vnode = dir_vnode;
}
return (error);
}
return (0);
}
/*
* If rewriting (RENAME), return the vnode and the
* information required to rewrite the present directory
* Must get node of directory entry to verify it's a
* regular file, or empty directory.
*/
if (op == RENAME && wantparent && (flags & ISLASTCN)) {
/*
* Careful about locking second node.
* This can only occur if the target is ".".
*/
if (dir_node == node) {
error = EISDIR;
goto drop_ref;
}
return (0);
}
/*
* Step through the translation in the name. We do not unlock the
* directory because we may need it again if a symbolic link
* is relative to the current directory. Instead we save it
* unlocked as "saved_dir_node" XXX. We must get the target
* node before unlocking
* the directory to insure that the node will not be removed
* before we get it. We prevent deadlock by always fetching
* nodes from the root, moving down the directory tree. Thus
* when following backward pointers ".." we must unlock the
* parent directory before getting the requested directory.
* There is a potential race condition here if both the current
* and parent directories are removed before the lock for the
* node associated with ".." returns. We hope that this occurs
* infrequently since we cannot avoid this race condition without
* implementing a sophisticated deadlock detection algorithm.
* Note also that this simple deadlock detection scheme will not
* work if the file system has any hard links other than ".."
* that point backwards in the directory structure.
*/
if ((flags & ISDOTDOT) == 0 && dir_node == node) {
if (*result_vnode) {
vnode_put(*result_vnode);
*result_vnode = NULL;
}
if ( (error = vnode_get(dir_vnode)) ) {
return (error);
}
*result_vnode = dir_vnode;
}
return (0);
drop_ref:
if (*result_vnode) {
vnode_put(*result_vnode);
*result_vnode = NULL;
}
return (error);
}
