1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * Portions of this source code were derived from Berkeley 4.3 BSD
31  * under license from the Regents of the University of California.
32  */
33 
34 #include <sys/param.h>
35 #include <sys/isa_defs.h>
36 #include <sys/types.h>
37 #include <sys/sysmacros.h>
38 #include <sys/systm.h>
39 #include <sys/errno.h>
40 #include <sys/pathname.h>
41 #include <sys/vfs.h>
42 #include <sys/vnode.h>
43 #include <sys/file.h>
44 #include <sys/fcntl.h>
45 #include <sys/proc.h>
46 #include <sys/uio.h>
47 #include <sys/debug.h>
48 #include <c2/audit.h>
49 #include <fs/fs_subr.h>
50 
51 /*
52  * Create a symbolic link.  Similar to link or rename except target
53  * name is passed as string argument, not converted to vnode reference.
54  */
55 int
56 symlinkat(char *target, int dfd, char *linkname)
57 {
58 	vnode_t *startvp;
59 	vnode_t *dvp;
60 	struct vattr vattr;
61 	struct pathname lpn;
62 	char *tbuf;
63 	size_t tlen;
64 	int error;
65 	int estale_retry = 0;
66 	int auditing = AU_AUDITING();
67 
68 	if (linkname == NULL)
69 		return (set_errno(EFAULT));
70 	if ((error = fgetstartvp(dfd, linkname, &startvp)) != 0)
71 		return (set_errno(error));
72 
73 top:
74 	if (error = pn_get(linkname, UIO_USERSPACE, &lpn))
75 		goto out;
76 	if (auditing && startvp != NULL)
77 		audit_setfsat_path(2);
78 	if (error = lookuppnat(&lpn, NULL, NO_FOLLOW, &dvp, NULLVPP, startvp)) {
79 		pn_free(&lpn);
80 		if (error == ESTALE && fs_need_estale_retry(estale_retry++))
81 			goto top;
82 		goto out;
83 	}
84 	if (vn_is_readonly(dvp))
85 		error = EROFS;
86 	else if (pn_fixslash(&lpn))
87 		error = ENOTDIR;
88 	else {
89 		tbuf = kmem_alloc(MAXPATHLEN, KM_SLEEP);
90 		if ((error = copyinstr(target, tbuf, MAXPATHLEN, &tlen)) == 0) {
91 			vattr.va_type = VLNK;
92 			vattr.va_mode = 0777;
93 			vattr.va_mask = AT_TYPE|AT_MODE;
94 			error = VOP_SYMLINK(dvp, lpn.pn_path, &vattr,
95 			    tbuf, CRED(), NULL, 0);
96 			if (auditing)
97 				audit_symlink_create(dvp, lpn.pn_path,
98 				    tbuf, error);
99 		}
100 		kmem_free(tbuf, MAXPATHLEN);
101 	}
102 	pn_free(&lpn);
103 	VN_RELE(dvp);
104 	if (error == ESTALE && fs_need_estale_retry(estale_retry++))
105 		goto top;
106 out:
107 	if (startvp != NULL)
108 		VN_RELE(startvp);
109 	if (error)
110 		return (set_errno(error));
111 	return (0);
112 }
113 
114 int
115 symlink(char *target, char *linkname)
116 {
117 	return (symlinkat(target, AT_FDCWD, linkname));
118 }
119