VOP_CREATE(9)

NAME

     VOP_CREATE, VOP_MKNOD, VOP_MKDIR, VOP_SYMLINK -- create a file, socket,
     fifo, device, directory or symlink

SYNOPSIS

     #include <sys/param.h>
     #include <sys/vnode.h>
     #include <sys/namei.h>

     int
     VOP_CREATE(struct vnode *dvp, struct vnode **vpp,
	 struct componentname *cnp, struct vattr *vap);

     int
     VOP_MKNOD(struct vnode *dvp, struct vnode **vpp,
	 struct componentname *cnp, struct vattr *vap);

     int
     VOP_MKDIR(struct vnode *dvp, struct vnode **vpp,
	 struct componentname *cnp, struct vattr *vap);

     int
     VOP_SYMLINK(struct vnode *dvp, struct vnode **vpp,
	 struct componentname *cnp, struct vattr *vap, char *target);

DESCRIPTION

     These entry points create a new file, socket, fifo, device, directory or
     symlink in a given directory.

     The arguments are:

     dvp     the locked vnode of the directory

     vpp     the address of a variable where the resulting locked vnode should
	     be stored

     cnp     the pathname component created

     vap     the attributes that the new object should be created with

     target  the pathname of the target of the symlink

     These entry points are called after VOP_LOOKUP(9) when an object is being
     created.

LOCKS

     The directory, dvp will be locked on entry and must remain locked on
     return.  If the call is successful, the new object will be returned
     locked.

RETURN VALUES

     If successful, the vnode for the new object is placed in *vpp and zero is
     returned.	Otherwise, an appropriate error is returned.

PSEUDOCODE

     int
     vop_create(struct vnode *dvp,
		struct vnode **vpp,
		struct componentname *cnp
		struct vattr *vap)
     {
	 int mode = MAKEIMODE(vap->va_type, vap->va_mode);
	 struct vnode *vp;
	 int error;

	 *vpp = NULL;
	 if ((mode & IFMT) == 0)
	     mode |= IFREG;

	 error = SOMEFS_VALLOC(dvp, mode, cnp->cn_cred, &vp);
	 if (error)
	     return error;

	 /*
	  * Update the permissions for the new vnode, including
	  * copying the group from the directory.
	  */
	 ...;

     #ifdef QUOTA
	 /*
	  * Possibly check quota information.
	  */
	 ...;
     #endif

	 /*
	  * Enter new vnode in directory, taking care that the vnode
	  * hits the disk before the directory contents are changed.
	  */
	 error = ...;

	 if (error)
	     goto bad;

	 *vpp = vp;

	 return 0;

     bad:
	 /*
	  * Write error occurred trying to update the inode
	  * or the directory so must deallocate the inode.
	  */
	 vput(vp);

	 /*
	  * Deallocate file system resources for vp.
	  */
	 ...;

	 return error;
     }

ERRORS

     [ENOSPC]		The file system is full.

     [EDQUOT]		The user's file system space or inode quota would be
			exceeded.

SEE ALSO

     VOP_LOOKUP(9)

HISTORY

     The function VOP_CREATE appeared in 4.3BSD.

SEE ALSO

     vnode(9)

AUTHORS

     This man page was written by Doug Rabson.