1 /* $OpenBSD: compat_util.c,v 1.10 2004/08/01 06:22:28 mickey Exp $ */
2 /* $NetBSD: compat_util.c,v 1.4 1996/03/14 19:31:45 christos Exp $ */
3
4 /*
5 * Copyright (c) 1994 Christos Zoulas
6 * Copyright (c) 1995 Frank van der Linden
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. The name of the author may not be used to endorse or promote products
18 * derived from this software without specific prior written permission
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 */
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/namei.h>
36 #include <sys/proc.h>
37 #include <sys/file.h>
38 #include <sys/stat.h>
39 #include <sys/filedesc.h>
40 #include <sys/ioctl.h>
41 #include <sys/kernel.h>
42 #include <sys/malloc.h>
43 #include <sys/vnode.h>
44
45 #include <compat/common/compat_util.h>
46
47 /*
48 * Search an alternate path before passing pathname arguments on
49 * to system calls. Useful for keeping a separate 'emulation tree'.
50 *
51 * If cflag is set, we check if an attempt can be made to create
52 * the named file, i.e. we check if the directory it should
53 * be in exists.
54 */
55 int
56 emul_find(p, sgp, prefix, path, pbuf, cflag)
57 struct proc *p;
58 caddr_t *sgp; /* Pointer to stackgap memory */
59 const char *prefix;
60 char *path;
61 char **pbuf;
62 int cflag;
63 {
64 struct nameidata nd;
65 struct nameidata ndroot;
66 struct vattr vat;
67 struct vattr vatroot;
68 int error;
69 char *ptr, *buf, *cp;
70 const char *pr;
71 size_t sz, len;
72
73 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
74 *pbuf = path;
75
76 for (ptr = buf, pr = prefix; (*ptr = *pr) != '\0'; ptr++, pr++)
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 goto bad;
91
92 if (*ptr != '/') {
93 error = EINVAL;
94 goto bad;
95 }
96
97 /*
98 * We know that there is a / somewhere in this pathname.
99 * Search backwards for it, to find the file's parent dir
100 * to see if it exists in the alternate tree. If it does,
101 * and we want to create a file (cflag is set). We don't
102 * need to worry about the root comparison in this case.
103 */
104
105 if (cflag) {
106 for (cp = &ptr[len] - 1; *cp != '/'; cp--)
107 ;
108 *cp = '\0';
109
110 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
111
112 if ((error = namei(&nd)) != 0)
113 goto bad;
114
115 *cp = '/';
116 }
117 else {
118 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
119
120 if ((error = namei(&nd)) != 0)
121 goto bad;
122
123 /*
124 * We now compare the vnode of the emulation root to the one
125 * vnode asked. If they resolve to be the same, then we
126 * ignore the match so that the real root gets used.
127 * This avoids the problem of traversing "../.." to find the
128 * root directory and never finding it, because "/" resolves
129 * to the emulation root directory. This is expensive :-(
130 */
131 /* XXX: prototype should have const here for NDINIT */
132 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, p);
133
134 if ((error = namei(&ndroot)) != 0)
135 goto bad2;
136
137 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0)
138 goto bad3;
139
140 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p))
141 != 0)
142 goto bad3;
143
144 if (vat.va_fsid == vatroot.va_fsid &&
145 vat.va_fileid == vatroot.va_fileid) {
146 error = ENOENT;
147 goto bad3;
148 }
149 }
150 if (sgp == NULL)
151 *pbuf = buf;
152 else {
153 sz = &ptr[len] - buf;
154 *pbuf = stackgap_alloc(sgp, sz + 1);
155 if (*pbuf == NULL) {
156 error = ENAMETOOLONG;
157 goto bad;
158 }
159 if ((error = copyout(buf, *pbuf, sz)) != 0) {
160 *pbuf = path;
161 goto bad;
162 }
163 free(buf, M_TEMP);
164 }
165
166 vrele(nd.ni_vp);
167 if (!cflag)
168 vrele(ndroot.ni_vp);
169 return error;
170
171 bad3:
172 vrele(ndroot.ni_vp);
173 bad2:
174 vrele(nd.ni_vp);
175 bad:
176 free(buf, M_TEMP);
177 return error;
178 }
179
180 /*
181 * Translate one set of flags to another, based on the entries in
182 * the given table. If 'leftover' is specified, it is filled in
183 * with any flags which could not be translated.
184 */
185 unsigned long
186 emul_flags_translate(tab, in, leftover)
187 const struct emul_flags_xtab *tab;
188 unsigned long in;
189 unsigned long *leftover;
190 {
191 unsigned long out;
192
193 for (out = 0; tab->omask != 0; tab++) {
194 if ((in & tab->omask) == tab->oval) {
195 in &= ~tab->omask;
196 out |= tab->nval;
197 }
198 }
199 if (leftover != NULL)
200 *leftover = in;
201 return (out);
202 }
203
204 caddr_t
205 stackgap_init(e)
206 struct emul *e;
207 {
208 return STACKGAPBASE;
209 }
210
211 void *
212 stackgap_alloc(sgp, sz)
213 caddr_t *sgp;
214 size_t sz;
215 {
216 void *n = (void *) *sgp;
217 caddr_t nsgp;
218
219 sz = ALIGN(sz);
220 nsgp = *sgp + sz;
221 #ifdef MACHINE_STACK_GROWS_UP
222 if (nsgp > ((caddr_t)PS_STRINGS) + STACKGAPLEN)
223 return NULL;
224 #else
225 if (nsgp > ((caddr_t)PS_STRINGS))
226 return NULL;
227 #endif
228 *sgp = nsgp;
229 return n;
230 }