[apple/xnu.git] / bsd / hfs / hfs_link.c

/*
 * Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */


#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <vfs/vfs_support.h>
#include <libkern/libkern.h>

#include "hfs.h"
#include "hfs_catalog.h"
#include "hfs_format.h"
#include "hfs_endian.h"


/*
 * Create a new indirect link
 *
 * An indirect link is a reference to a data node.  The only useable
 * fields in the link are the link number, parentID, name and text
 * encoding.  All other catalog fields are ignored.
 */
static int
createindirectlink(struct hfsmount *hfsmp, u_int32_t linknum,
			u_int32_t linkparid, char *linkName, cnid_t *linkcnid)
{
	struct FndrFileInfo *fip;
	struct cat_desc desc;
	struct cat_attr attr;
	int result;

	/* Setup the descriptor */
	bzero(&desc, sizeof(desc));
	desc.cd_nameptr = linkName;
	desc.cd_namelen = strlen(linkName);
	desc.cd_parentcnid = linkparid;

	/* Setup the default attributes */
	bzero(&attr, sizeof(attr));
	
	/* links are matched to data nodes by link ID and to volumes by create date */
	attr.ca_rdev = linknum;  /* note: cat backend overloads ca_rdev to be the linknum when nlink = 0 */
	attr.ca_itime = HFSTOVCB(hfsmp)->vcbCrDate;
	attr.ca_mode = S_IFREG;

	fip = (struct FndrFileInfo *)&attr.ca_finderinfo;
	fip->fdType    = SWAP_BE32 (kHardLinkFileType);	/* 'hlnk' */
	fip->fdCreator = SWAP_BE32 (kHFSPlusCreator);	/* 'hfs+' */
	fip->fdFlags   = SWAP_BE16 (kHasBeenInited);

	/* Create the indirect link directly in the catalog */
	result = cat_create(hfsmp, &desc, &attr, NULL);

	if (linkcnid != NULL)
		*linkcnid = attr.ca_fileid;

	return (result);
}


/*
 * 2 locks are needed (dvp and vp)
 * also need catalog lock
 *
 * caller's responsibility:
 *		componentname cleanup
 *		unlocking dvp and vp
 */
static int
hfs_makelink(struct hfsmount *hfsmp, struct cnode *cp, struct cnode *dcp,
		struct componentname *cnp)
{
	struct proc *p = cnp->cn_proc;
	u_int32_t indnodeno = 0;
	char inodename[32];
	struct cat_desc to_desc;
	int newlink = 0;
	int retval;


	/* We don't allow link nodes in our Private Meta Data folder! */
	if (dcp->c_fileid == hfsmp->hfs_privdir_desc.cd_cnid)
		return (EPERM);

	if (hfs_freeblks(hfsmp, 0) == 0)
		return (ENOSPC);

	/* Lock catalog b-tree */
	retval = hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_EXCLUSIVE, p);
	if (retval)
		return retval;

	/*
	 * If this is a new hardlink then we need to create the data
	 * node (inode) and replace the original file with a link node.
	 */
	if (cp->c_nlink == 2 && (cp->c_flag & C_HARDLINK) == 0) {
		newlink = 1;
		bzero(&to_desc, sizeof(to_desc));
		to_desc.cd_parentcnid = hfsmp->hfs_privdir_desc.cd_cnid;
		to_desc.cd_cnid = cp->c_fileid;
		do {
			/* get a unique indirect node number */
			indnodeno = ((random() & 0x3fffffff) + 100);
			MAKE_INODE_NAME(inodename, indnodeno);

			/* move source file to data node directory */
			to_desc.cd_nameptr = inodename;
			to_desc.cd_namelen = strlen(inodename);
		
			retval = cat_rename(hfsmp, &cp->c_desc, &hfsmp->hfs_privdir_desc,
					&to_desc, NULL);

		} while (retval == EEXIST);
		if (retval)
			goto out;

		/* Replace source file with link node */
		retval = createindirectlink(hfsmp, indnodeno, cp->c_parentcnid,
				cp->c_desc.cd_nameptr, &cp->c_desc.cd_cnid);
		if (retval) {
			/* put it source file back */
			(void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
			goto out;
		}
		cp->c_rdev = indnodeno;
	} else {
		indnodeno = cp->c_rdev;
	}

	/*
	 * Create a catalog entry for the new link (parentID + name).
	 */
	retval = createindirectlink(hfsmp, indnodeno, dcp->c_fileid, cnp->cn_nameptr, NULL);
	if (retval && newlink) {
		/* Get rid of new link */
		(void) cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);

		/* Put the source file back */
		(void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
		goto out;
	}

	/*
	 * Finally, if this is a new hardlink then:
	 *  - update HFS Private Data dir
	 *  - mark the cnode as a hard link
	 */
	if (newlink) {
		hfsmp->hfs_privdir_attr.ca_entries++;
		(void)cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
			&hfsmp->hfs_privdir_attr, NULL, NULL);
		hfs_volupdate(hfsmp, VOL_MKFILE, 0);
		cp->c_flag |= (C_CHANGE | C_HARDLINK);
	}

out:
	/* Unlock catalog b-tree */
	(void) hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_RELEASE, p);

	return (retval);
}


/*
 * link vnode call
#% link		vp	U U U
#% link		tdvp	L U U
#
 vop_link {
     IN WILLRELE struct vnode *vp;
     IN struct vnode *targetPar_vp;
     IN struct componentname *cnp;

     */
int
hfs_link(ap)
	struct vop_link_args /* {
		struct vnode *a_vp;
		struct vnode *a_tdvp;
		struct componentname *a_cnp;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct vnode *tdvp = ap->a_tdvp;
	struct componentname *cnp = ap->a_cnp;
	struct proc *p = cnp->cn_proc;
	struct cnode *cp;
	struct cnode *tdcp;
	struct timeval tv;
	int error;

#if HFS_DIAGNOSTIC
	if ((cnp->cn_flags & HASBUF) == 0)
		panic("hfs_link: no name");
#endif
	if (tdvp->v_mount != vp->v_mount) {
		VOP_ABORTOP(tdvp, cnp);
		error = EXDEV;
		goto out2;
	}
	if (VTOVCB(tdvp)->vcbSigWord != kHFSPlusSigWord)
		return err_link(ap);	/* hfs disks don't support hard links */
	
	if (VTOHFS(vp)->hfs_private_metadata_dir == 0)
		return err_link(ap);	/* no private metadata dir, no links possible */

	if (tdvp != vp && (error = vn_lock(vp, LK_EXCLUSIVE, p))) {
		VOP_ABORTOP(tdvp, cnp);
		goto out2;
	}
	cp = VTOC(vp);
	tdcp = VTOC(tdvp);

	if (cp->c_nlink >= HFS_LINK_MAX) {
		VOP_ABORTOP(tdvp, cnp);
		error = EMLINK;
		goto out1;
	}
	if (cp->c_flags & (IMMUTABLE | APPEND)) {
		VOP_ABORTOP(tdvp, cnp);
		error = EPERM;
		goto out1;
	}
	if (vp->v_type == VBLK || vp->v_type == VCHR) {
		VOP_ABORTOP(tdvp, cnp);
		error = EINVAL;  /* cannot link to a special file */
		goto out1;
	}

	cp->c_nlink++;
	cp->c_flag |= C_CHANGE;
	tv = time;
	error = VOP_UPDATE(vp, &tv, &tv, 1);
	if (!error)
		error = hfs_makelink(VTOHFS(vp), cp, tdcp, cnp);
	if (error) {
		cp->c_nlink--;
		cp->c_flag |= C_CHANGE;
	} else {
		/* Update the target directory and volume stats */
		tdcp->c_nlink++;
		tdcp->c_entries++;
		tdcp->c_flag |= C_CHANGE | C_UPDATE;
		tv = time;
		(void) VOP_UPDATE(tdvp, &tv, &tv, 0);
		hfs_volupdate(VTOHFS(vp), VOL_MKFILE,
			(tdcp->c_cnid == kHFSRootFolderID));
	}
	FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
out1:
	if (tdvp != vp)
		VOP_UNLOCK(vp, 0, p);
out2:
	vput(tdvp);
	return (error);
}
Commit	Line	Data
1c79356b	1	/*
9bccf70c	2	* Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
1c79356b A	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
	11	*
	12	* This Original Code and all software distributed under the License are
	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22
1c79356b A	23
	24	#include <sys/systm.h>
	25	#include <sys/kernel.h>
	26	#include <sys/malloc.h>
9bccf70c	27	#include <sys/mount.h>
1c79356b A	28	#include <sys/namei.h>
	29	#include <sys/stat.h>
	30	#include <sys/vnode.h>
	31	#include <vfs/vfs_support.h>
	32	#include <libkern/libkern.h>
	33
	34	#include "hfs.h"
9bccf70c A	35	#include "hfs_catalog.h"
	36	#include "hfs_format.h"
	37	#include "hfs_endian.h"
1c79356b A	38
	39
	40	/*
	41	* Create a new indirect link
	42	*
9bccf70c A	43	* An indirect link is a reference to a data node. The only useable
	44	* fields in the link are the link number, parentID, name and text
	45	* encoding. All other catalog fields are ignored.
1c79356b A	46	*/
1c79356b A	47	static int
9bccf70c A	48	createindirectlink(struct hfsmount *hfsmp, u_int32_t linknum,
9bccf70c A	49	u_int32_t linkparid, char linkName, cnid_t linkcnid)
1c79356b	50	{
9bccf70c A	51	struct FndrFileInfo *fip;
	52	struct cat_desc desc;
	53	struct cat_attr attr;
1c79356b A	54	int result;
1c79356b A	55
9bccf70c A	56	/* Setup the descriptor */
	57	bzero(&desc, sizeof(desc));
	58	desc.cd_nameptr = linkName;
	59	desc.cd_namelen = strlen(linkName);
	60	desc.cd_parentcnid = linkparid;
1c79356b	61
9bccf70c A	62	/* Setup the default attributes */
	63	bzero(&attr, sizeof(attr));
	64
	65	/* links are matched to data nodes by link ID and to volumes by create date */
	66	attr.ca_rdev = linknum; /* note: cat backend overloads ca_rdev to be the linknum when nlink = 0 */
	67	attr.ca_itime = HFSTOVCB(hfsmp)->vcbCrDate;
	68	attr.ca_mode = S_IFREG;
1c79356b	69
9bccf70c A	70	fip = (struct FndrFileInfo *)&attr.ca_finderinfo;
	71	fip->fdType = SWAP_BE32 (kHardLinkFileType); /* 'hlnk' */
	72	fip->fdCreator = SWAP_BE32 (kHFSPlusCreator); /* 'hfs+' */
	73	fip->fdFlags = SWAP_BE16 (kHasBeenInited);
1c79356b	74
9bccf70c A	75	/* Create the indirect link directly in the catalog */
9bccf70c A	76	result = cat_create(hfsmp, &desc, &attr, NULL);
1c79356b	77
9bccf70c A	78	if (linkcnid != NULL)
9bccf70c A	79	*linkcnid = attr.ca_fileid;
1c79356b A	80
	81	return (result);
	82	}
	83
	84
	85	/*
9bccf70c	86	* 2 locks are needed (dvp and vp)
1c79356b A	87	* also need catalog lock
	88	*
	89	* caller's responsibility:
	90	* componentname cleanup
9bccf70c	91	* unlocking dvp and vp
1c79356b A	92	*/
1c79356b A	93	static int
9bccf70c A	94	hfs_makelink(struct hfsmount hfsmp, struct cnode cp, struct cnode *dcp,
9bccf70c A	95	struct componentname *cnp)
1c79356b A	96	{
1c79356b A	97	struct proc *p = cnp->cn_proc;
1c79356b A	98	u_int32_t indnodeno = 0;
1c79356b A	99	char inodename[32];
9bccf70c A	100	struct cat_desc to_desc;
9bccf70c A	101	int newlink = 0;
1c79356b A	102	int retval;
1c79356b A	103
1c79356b A	104
1c79356b A	105	/* We don't allow link nodes in our Private Meta Data folder! */
9bccf70c	106	if (dcp->c_fileid == hfsmp->hfs_privdir_desc.cd_cnid)
1c79356b A	107	return (EPERM);
1c79356b A	108
9bccf70c	109	if (hfs_freeblks(hfsmp, 0) == 0)
1c79356b A	110	return (ENOSPC);
1c79356b A	111
9bccf70c A	112	/* Lock catalog b-tree */
	113	retval = hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_EXCLUSIVE, p);
	114	if (retval)
1c79356b A	115	return retval;
	116
	117	/*
	118	* If this is a new hardlink then we need to create the data
	119	* node (inode) and replace the original file with a link node.
	120	*/
9bccf70c A	121	if (cp->c_nlink == 2 && (cp->c_flag & C_HARDLINK) == 0) {
	122	newlink = 1;
	123	bzero(&to_desc, sizeof(to_desc));
	124	to_desc.cd_parentcnid = hfsmp->hfs_privdir_desc.cd_cnid;
	125	to_desc.cd_cnid = cp->c_fileid;
1c79356b A	126	do {
	127	/* get a unique indirect node number */
	128	indnodeno = ((random() & 0x3fffffff) + 100);
	129	MAKE_INODE_NAME(inodename, indnodeno);
	130
	131	/* move source file to data node directory */
9bccf70c A	132	to_desc.cd_nameptr = inodename;
	133	to_desc.cd_namelen = strlen(inodename);
	134
	135	retval = cat_rename(hfsmp, &cp->c_desc, &hfsmp->hfs_privdir_desc,
	136	&to_desc, NULL);
1c79356b	137
9bccf70c A	138	} while (retval == EEXIST);
	139	if (retval)
	140	goto out;
1c79356b	141
9bccf70c A	142	/* Replace source file with link node */
	143	retval = createindirectlink(hfsmp, indnodeno, cp->c_parentcnid,
	144	cp->c_desc.cd_nameptr, &cp->c_desc.cd_cnid);
1c79356b A	145	if (retval) {
1c79356b A	146	/* put it source file back */
9bccf70c	147	(void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
1c79356b A	148	goto out;
1c79356b A	149	}
9bccf70c A	150	cp->c_rdev = indnodeno;
	151	} else {
	152	indnodeno = cp->c_rdev;
	153	}
1c79356b A	154
	155	/*
	156	* Create a catalog entry for the new link (parentID + name).
	157	*/
9bccf70c A	158	retval = createindirectlink(hfsmp, indnodeno, dcp->c_fileid, cnp->cn_nameptr, NULL);
	159	if (retval && newlink) {
	160	/* Get rid of new link */
	161	(void) cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);
	162
	163	/* Put the source file back */
	164	(void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
1c79356b A	165	goto out;
	166	}
	167
	168	/*
9bccf70c A	169	* Finally, if this is a new hardlink then:
	170	* - update HFS Private Data dir
	171	* - mark the cnode as a hard link
1c79356b	172	*/
9bccf70c A	173	if (newlink) {
	174	hfsmp->hfs_privdir_attr.ca_entries++;
	175	(void)cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
	176	&hfsmp->hfs_privdir_attr, NULL, NULL);
	177	hfs_volupdate(hfsmp, VOL_MKFILE, 0);
	178	cp->c_flag \|= (C_CHANGE \| C_HARDLINK);
1c79356b A	179	}
	180
	181	out:
9bccf70c A	182	/* Unlock catalog b-tree */
9bccf70c A	183	(void) hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_RELEASE, p);
1c79356b A	184
	185	return (retval);
	186	}
	187
	188
	189	/*
	190	* link vnode call
	191	#% link vp U U U
	192	#% link tdvp L U U
	193	#
	194	vop_link {
	195	IN WILLRELE struct vnode *vp;
	196	IN struct vnode *targetPar_vp;
	197	IN struct componentname *cnp;
	198
	199	*/
	200	int
	201	hfs_link(ap)
9bccf70c A	202	struct vop_link_args /* {
	203	struct vnode *a_vp;
	204	struct vnode *a_tdvp;
	205	struct componentname *a_cnp;
	206	} / ap;
1c79356b A	207	{
	208	struct vnode *vp = ap->a_vp;
	209	struct vnode *tdvp = ap->a_tdvp;
	210	struct componentname *cnp = ap->a_cnp;
	211	struct proc *p = cnp->cn_proc;
9bccf70c A	212	struct cnode *cp;
9bccf70c A	213	struct cnode *tdcp;
1c79356b A	214	struct timeval tv;
	215	int error;
	216
	217	#if HFS_DIAGNOSTIC
	218	if ((cnp->cn_flags & HASBUF) == 0)
	219	panic("hfs_link: no name");
	220	#endif
	221	if (tdvp->v_mount != vp->v_mount) {
	222	VOP_ABORTOP(tdvp, cnp);
	223	error = EXDEV;
	224	goto out2;
	225	}
	226	if (VTOVCB(tdvp)->vcbSigWord != kHFSPlusSigWord)
	227	return err_link(ap); /* hfs disks don't support hard links */
	228
	229	if (VTOHFS(vp)->hfs_private_metadata_dir == 0)
	230	return err_link(ap); /* no private metadata dir, no links possible */
	231
	232	if (tdvp != vp && (error = vn_lock(vp, LK_EXCLUSIVE, p))) {
	233	VOP_ABORTOP(tdvp, cnp);
	234	goto out2;
	235	}
9bccf70c A	236	cp = VTOC(vp);
	237	tdcp = VTOC(tdvp);
	238
	239	if (cp->c_nlink >= HFS_LINK_MAX) {
1c79356b A	240	VOP_ABORTOP(tdvp, cnp);
	241	error = EMLINK;
	242	goto out1;
	243	}
9bccf70c	244	if (cp->c_flags & (IMMUTABLE \| APPEND)) {
1c79356b A	245	VOP_ABORTOP(tdvp, cnp);
	246	error = EPERM;
	247	goto out1;
	248	}
	249	if (vp->v_type == VBLK \|\| vp->v_type == VCHR) {
	250	VOP_ABORTOP(tdvp, cnp);
	251	error = EINVAL; /* cannot link to a special file */
	252	goto out1;
	253	}
	254
9bccf70c A	255	cp->c_nlink++;
9bccf70c A	256	cp->c_flag \|= C_CHANGE;
1c79356b A	257	tv = time;
	258	error = VOP_UPDATE(vp, &tv, &tv, 1);
	259	if (!error)
9bccf70c	260	error = hfs_makelink(VTOHFS(vp), cp, tdcp, cnp);
1c79356b	261	if (error) {
9bccf70c A	262	cp->c_nlink--;
	263	cp->c_flag \|= C_CHANGE;
	264	} else {
	265	/* Update the target directory and volume stats */
	266	tdcp->c_nlink++;
	267	tdcp->c_entries++;
	268	tdcp->c_flag \|= C_CHANGE \| C_UPDATE;
	269	tv = time;
	270	(void) VOP_UPDATE(tdvp, &tv, &tv, 0);
	271	hfs_volupdate(VTOHFS(vp), VOL_MKFILE,
	272	(tdcp->c_cnid == kHFSRootFolderID));
1c79356b A	273	}
	274	FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
	275	out1:
	276	if (tdvp != vp)
	277	VOP_UNLOCK(vp, 0, p);
	278	out2:
	279	vput(tdvp);
	280	return (error);
	281	}