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 * $FreeBSD$ 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/malloc.h> 38 #include <sys/vnode.h> 39 40 #include <i386/linux/linux_util.h> 41 42 #include <vm/vm_zone.h> 43 44 const char linux_emul_path[] = "/compat/linux"; 45 46 /* 47 * Search an alternate path before passing pathname arguments on 48 * to system calls. Useful for keeping a seperate 'emulation tree'. 49 * 50 * If cflag is set, we check if an attempt can be made to create 51 * the named file, i.e. we check if the directory it should 52 * be in exists. 53 */ 54 int 55 linux_emul_find(p, sgp, prefix, path, pbuf, cflag) 56 struct proc *p; 57 caddr_t *sgp; /* Pointer to stackgap memory */ 58 const char *prefix; 59 char *path; 60 char **pbuf; 61 int cflag; 62 { 63 struct nameidata nd; 64 struct nameidata ndroot; 65 struct vattr vat; 66 struct vattr vatroot; 67 int error; 68 char *ptr, *buf, *cp; 69 size_t sz, len; 70 71 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 72 *pbuf = path; 73 74 for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++) 75 continue; 76 77 sz = MAXPATHLEN - (ptr - buf); 78 79 /* 80 * If sgp is not given then the path is already in kernel space 81 */ 82 if (sgp == NULL) 83 error = copystr(path, ptr, sz, &len); 84 else 85 error = copyinstr(path, ptr, sz, &len); 86 87 if (error) { 88 free(buf, M_TEMP); 89 return error; 90 } 91 92 if (*ptr != '/') { 93 free(buf, M_TEMP); 94 return EINVAL; 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 *cp = '\0'; 108 109 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 110 111 if ((error = namei(&nd)) != 0) { 112 free(buf, M_TEMP); 113 return error; 114 } 115 116 *cp = '/'; 117 } 118 else { 119 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 120 121 if ((error = namei(&nd)) != 0) { 122 free(buf, M_TEMP); 123 return error; 124 } 125 126 /* 127 * We now compare the vnode of the linux_root to the one 128 * vnode asked. If they resolve to be the same, then we 129 * ignore the match so that the real root gets used. 130 * This avoids the problem of traversing "../.." to find the 131 * root directory and never finding it, because "/" resolves 132 * to the emulation root directory. This is expensive :-( 133 */ 134 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path, 135 p); 136 137 if ((error = namei(&ndroot)) != 0) { 138 /* Cannot happen! */ 139 free(buf, M_TEMP); 140 NDFREE(&nd, NDF_ONLY_PNBUF); 141 vrele(nd.ni_vp); 142 return error; 143 } 144 145 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) { 146 goto bad; 147 } 148 149 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p)) 150 != 0) { 151 goto bad; 152 } 153 154 if (vat.va_fsid == vatroot.va_fsid && 155 vat.va_fileid == vatroot.va_fileid) { 156 error = ENOENT; 157 goto bad; 158 } 159 160 } 161 if (sgp == NULL) 162 *pbuf = buf; 163 else { 164 sz = &ptr[len] - buf; 165 *pbuf = stackgap_alloc(sgp, sz + 1); 166 error = copyout(buf, *pbuf, sz); 167 free(buf, M_TEMP); 168 } 169 170 NDFREE(&nd, NDF_ONLY_PNBUF); 171 vrele(nd.ni_vp); 172 if (!cflag) { 173 NDFREE(&ndroot, NDF_ONLY_PNBUF); 174 vrele(ndroot.ni_vp); 175 } 176 return error; 177 178 bad: 179 NDFREE(&ndroot, NDF_ONLY_PNBUF); 180 vrele(ndroot.ni_vp); 181 NDFREE(&nd, NDF_ONLY_PNBUF); 182 vrele(nd.ni_vp); 183 free(buf, M_TEMP); 184 return error; 185 } 186