Split mkfifo().
[dragonfly.git] / sys / emulation / linux / linux_util.c
CommitLineData
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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 * $FreeBSD: src/sys/compat/linux/linux_util.c,v 1.12.2.2 2001/11/05 19:08:23 marcel Exp $
136178b3 31 * $DragonFly: src/sys/emulation/linux/linux_util.c,v 1.8 2003/11/13 04:04:42 daver Exp $
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32 */
33
34#include <sys/param.h>
35#include <sys/systm.h>
984263bc 36#include <sys/proc.h>
dadab5e9 37#include <sys/namei.h>
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38#include <sys/malloc.h>
39#include <sys/vnode.h>
40
1f2de5d4 41#include "linux_util.h"
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42
43const char linux_emul_path[] = "/compat/linux";
44
45/*
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46 * Search for an alternate path before passing pathname arguments on
47 * to system calls.
984263bc 48 *
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49 * Only signal an error if something really bad happens. In most cases
50 * we can just return the untranslated path, eg. name lookup failures.
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51 */
52int
136178b3 53linux_copyin_path(char *uname, char **kname, int flags)
984263bc 54{
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55 struct thread *td = curthread;
56 struct nameidata nd, ndroot;
57 struct vattr vat, vatroot;
58 char *buf, *cp;
59 int error, length, dummy;
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60
61 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
136178b3 62 *kname = buf;
984263bc 63
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64 /*
65 * Don't bother trying to translate if the path is relative.
984263bc 66 */
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67 if (fubyte(uname) != '/')
68 goto dont_translate;
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69
70 /*
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71 * The path is absolute. Prepend the buffer with the emulation
72 * path and copy in.
984263bc 73 */
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74 length = strlen(linux_emul_path);
75 bcopy(linux_emul_path, buf, length);
76 error = copyinstr(uname, buf + length, MAXPATHLEN - length, &dummy);
77 if (error) {
78 linux_free_path(kname);
79 return (error);
80 }
984263bc 81
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82 switch (flags) {
83 case LINUX_PATH_CREATE:
84 /*
85 * Check to see if the parent directory exists in the
86 * emulation tree. Walk the string backwards to find
87 * the last '/'.
88 */
89 cp = buf + strlen(buf);
90 while (*--cp != '/');
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91 *cp = '\0';
92
2b69e610 93 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE, buf, td);
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94 error = namei(&nd);
95 if (error)
96 goto dont_translate;
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97
98 *cp = '/';
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99 return (0);
100 case LINUX_PATH_EXISTS:
2b69e610 101 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE, buf, td);
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102 error = namei(&nd);
103 if (error)
104 goto dont_translate;
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105
106 /*
107 * We now compare the vnode of the linux_root to the one
108 * vnode asked. If they resolve to be the same, then we
109 * ignore the match so that the real root gets used.
110 * This avoids the problem of traversing "../.." to find the
111 * root directory and never finding it, because "/" resolves
112 * to the emulation root directory. This is expensive :-(
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113 *
114 * The next three function calls should not return errors.
115 * If they do something is seriously wrong, eg. the
116 * emulation subtree does not exist. Cross our fingers
117 * and return the untranslated path if something happens.
984263bc 118 */
2b69e610 119 NDINIT(&ndroot, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE,
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120 linux_emul_path, td);
121 error = namei(&ndroot);
122 if (error)
123 goto dont_translate;
124
125 error = VOP_GETATTR(nd.ni_vp, &vat, td);
126 if (error)
127 goto dont_translate;
128
129 error = VOP_GETATTR(ndroot.ni_vp, &vatroot, td);
130 if (error)
131 goto dont_translate;
984263bc 132
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133 if (vat.va_fsid == vatroot.va_fsid &&
134 vat.va_fileid == vatroot.va_fileid)
135 goto dont_translate;
984263bc 136
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137 return (0);
138 default:
139 linux_free_path(kname);
140 return (EINVAL);
141 }
142
143dont_translate:
984263bc 144
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145 error = copyinstr(uname, buf, MAXPATHLEN, &dummy);
146 if (error)
147 linux_free_path(kname);
148 return (error);
149}
984263bc 150
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151/*
152 * Smaller version of the above for translating in kernel buffers. Only
153 * used in exec_linux_imgact_try(). Only check is path exists.
154 */
155int
156linux_translate_path(char *path, int size)
157{
158 struct thread *td = curthread;
159 struct nameidata nd;
160 char *buf;
161 int error, length, dummy;
984263bc 162
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163 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
164 length = strlen(linux_emul_path);
165 bcopy(linux_emul_path, buf, length);
166 error = copystr(path, buf + length, MAXPATHLEN - length, &dummy);
167 if (error)
168 goto cleanup;
169
170 /*
171 * If this errors, then the path probably doesn't exists.
172 */
173 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE, buf, td);
174 error = namei(&nd);
175 if (error) {
176 error = 0;
177 goto cleanup;
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178 }
179
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180 /*
181 * The alternate path does exist. Return it in the buffer if
182 * it fits.
183 */
184 if (strlen(buf) + 1 <= size)
185 error = copystr(buf, path, size, &dummy);
186
187cleanup:
984263bc 188
984263bc 189 free(buf, M_TEMP);
136178b3 190 return (error);
984263bc 191}