1 /*
2 * Copyright (c) 1994 Christos Zoulas
3 * Copyright (c) 1995 Frank van der Linden
4 * Copyright (c) 1995 Scott Bartram
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * from: svr4_util.c,v 1.5 1995/01/22 23:44:50 christos Exp
30 */
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/namei.h>
35 #include <sys/malloc.h>
36 #include <sys/vnode.h>
37
38 #include <i386/ibcs2/ibcs2_util.h>
39
40 const char ibcs2_emul_path[] = "/compat/ibcs2";
41
42 /*
43 * Search an alternate path before passing pathname arguments on
44 * to system calls. Useful for keeping a seperate 'emulation tree'.
45 *
46 * If cflag is set, we check if an attempt can be made to create
47 * the named file, i.e. we check if the directory it should
48 * be in exists.
49 */
50 int
51 ibcs2_emul_find(p, sgp, prefix, path, pbuf, cflag)
52 struct proc *p;
53 caddr_t *sgp; /* Pointer to stackgap memory */
54 const char *prefix;
55 char *path;
56 char **pbuf;
57 int cflag;
58 {
59 struct nameidata nd;
60 struct nameidata ndroot;
61 struct vattr vat;
62 struct vattr vatroot;
63 int error;
64 char *ptr, *buf, *cp;
65 size_t sz, len;
66
67 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
68 *pbuf = path;
69
70 for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++)
71 continue;
72
73 sz = MAXPATHLEN - (ptr - buf);
74
75 /*
76 * If sgp is not given then the path is already in kernel space
77 */
78 if (sgp == NULL)
79 error = copystr(path, ptr, sz, &len);
80 else
81 error = copyinstr(path, ptr, sz, &len);
82
83 if (error) {
84 free(buf, M_TEMP);
85 return error;
86 }
87
88 if (*ptr != '/') {
89 free(buf, M_TEMP);
90 return EINVAL;
91 }
92
93 /*
94 * We know that there is a / somewhere in this pathname.
95 * Search backwards for it, to find the file's parent dir
96 * to see if it exists in the alternate tree. If it does,
97 * and we want to create a file (cflag is set). We don't
98 * need to worry about the root comparison in this case.
99 */
100
101 if (cflag) {
102 for (cp = &ptr[len] - 1; *cp != '/'; cp--);
103 *cp = '\0';
104
105 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
106
107 if ((error = namei(&nd)) != 0) {
108 free(buf, M_TEMP);
109 return error;
110 }
111
112 *cp = '/';
113 }
114 else {
115 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
116
117 if ((error = namei(&nd)) != 0) {
118 free(buf, M_TEMP);
119 return error;
120 }
121
122 /*
123 * We now compare the vnode of the ibcs2_root to the one
124 * vnode asked. If they resolve to be the same, then we
125 * ignore the match so that the real root gets used.
126 * This avoids the problem of traversing "../.." to find the
127 * root directory and never finding it, because "/" resolves
128 * to the emulation root directory. This is expensive :-(
129 */
130 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, ibcs2_emul_path,
131 p);
132
133 if ((error = namei(&ndroot)) != 0) {
134 /* Cannot happen! */
135 free(buf, M_TEMP);
136 vrele(nd.ni_vp);
137 return error;
138 }
139
140 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) {
141 goto done;
142 }
143
144 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p))
145 != 0) {
146 goto done;
147 }
148
149 if (vat.va_fsid == vatroot.va_fsid &&
150 vat.va_fileid == vatroot.va_fileid) {
151 error = ENOENT;
152 goto done;
153 }
154
155 }
156 if (sgp == NULL)
157 *pbuf = buf;
158 else {
159 sz = &ptr[len] - buf;
160 *pbuf = stackgap_alloc(sgp, sz + 1);
161 error = copyout(buf, *pbuf, sz);
162 free(buf, M_TEMP);
163 }
164
165
166 done:
167 vrele(nd.ni_vp);
168 if (!cflag)
169 vrele(ndroot.ni_vp);
170 return error;
171 }
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