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/proc.h>
36 #include <sys/file.h>
37 #include <sys/stat.h>
38 #include <sys/filedesc.h>
39 #include <sys/ioctl.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/vnode.h>
43
44 #include <i386/ibcs2/ibcs2_util.h>
45
46 const char ibcs2_emul_path[] = "/compat/ibcs2";
47
48 /*
49 * Search an alternate path before passing pathname arguments on
50 * to system calls. Useful for keeping a seperate 'emulation tree'.
51 *
52 * If cflag is set, we check if an attempt can be made to create
53 * the named file, i.e. we check if the directory it should
54 * be in exists.
55 */
56 int
57 ibcs2_emul_find(p, sgp, prefix, path, pbuf, cflag)
58 struct proc *p;
59 caddr_t *sgp; /* Pointer to stackgap memory */
60 const char *prefix;
61 char *path;
62 char **pbuf;
63 int cflag;
64 {
65 struct nameidata nd;
66 struct nameidata ndroot;
67 struct vattr vat;
68 struct vattr vatroot;
69 int error;
70 char *ptr, *buf, *cp;
71 size_t sz, len;
72
73 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
74 *pbuf = path;
75
76 for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++)
77 continue;
78
79 sz = MAXPATHLEN - (ptr - buf);
80
81 /*
82 * If sgp is not given then the path is already in kernel space
83 */
84 if (sgp == NULL)
85 error = copystr(path, ptr, sz, &len);
86 else
87 error = copyinstr(path, ptr, sz, &len);
88
89 if (error) {
90 free(buf, M_TEMP);
91 return error;
92 }
93
94 if (*ptr != '/') {
95 free(buf, M_TEMP);
96 return EINVAL;
97 }
98
99 /*
100 * We know that there is a / somewhere in this pathname.
101 * Search backwards for it, to find the file's parent dir
102 * to see if it exists in the alternate tree. If it does,
103 * and we want to create a file (cflag is set). We don't
104 * need to worry about the root comparison in this case.
105 */
106
107 if (cflag) {
108 for (cp = &ptr[len] - 1; *cp != '/'; cp--);
109 *cp = '\0';
110
111 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
112
113 if ((error = namei(&nd)) != 0) {
114 free(buf, M_TEMP);
115 return error;
116 }
117
118 *cp = '/';
119 }
120 else {
121 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
122
123 if ((error = namei(&nd)) != 0) {
124 free(buf, M_TEMP);
125 return error;
126 }
127
128 /*
129 * We now compare the vnode of the ibcs2_root to the one
130 * vnode asked. If they resolve to be the same, then we
131 * ignore the match so that the real root gets used.
132 * This avoids the problem of traversing "../.." to find the
133 * root directory and never finding it, because "/" resolves
134 * to the emulation root directory. This is expensive :-(
135 */
136 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, ibcs2_emul_path,
137 p);
138
139 if ((error = namei(&ndroot)) != 0) {
140 /* Cannot happen! */
141 free(buf, M_TEMP);
142 vrele(nd.ni_vp);
143 return error;
144 }
145
146 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) {
147 goto done;
148 }
149
150 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p))
151 != 0) {
152 goto done;
153 }
154
155 if (vat.va_fsid == vatroot.va_fsid &&
156 vat.va_fileid == vatroot.va_fileid) {
157 error = ENOENT;
158 goto done;
159 }
160
161 }
162 if (sgp == NULL)
163 *pbuf = buf;
164 else {
165 sz = &ptr[len] - buf;
166 *pbuf = stackgap_alloc(sgp, sz + 1);
167 error = copyout(buf, *pbuf, sz);
168 free(buf, M_TEMP);
169 }
170
171
172 done:
173 vrele(nd.ni_vp);
174 if (!cflag)
175 vrele(ndroot.ni_vp);
176 return error;
177 }
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