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 <compat/linux/linux_util.h> 41 42 const char linux_emul_path[] = "/compat/linux"; 43 44 /* 45 * Search an alternate path before passing pathname arguments on 46 * to system calls. Useful for keeping a separate 'emulation tree'. 47 * 48 * If cflag is set, we check if an attempt can be made to create 49 * the named file, i.e. we check if the directory it should 50 * be in exists. 51 */ 52 int 53 linux_emul_find(p, sgp, prefix, path, pbuf, cflag) 54 struct proc *p; 55 caddr_t *sgp; /* Pointer to stackgap memory */ 56 const char *prefix; 57 char *path; 58 char **pbuf; 59 int cflag; 60 { 61 struct nameidata nd; 62 struct nameidata ndroot; 63 struct vattr vat; 64 struct vattr vatroot; 65 int error; 66 char *ptr, *buf, *cp; 67 size_t sz, len; 68 69 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 70 *pbuf = path; 71 72 for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++) 73 continue; 74 75 sz = MAXPATHLEN - (ptr - buf); 76 77 /* 78 * If sgp is not given then the path is already in kernel space 79 */ 80 if (sgp == NULL) 81 error = copystr(path, ptr, sz, &len); 82 else 83 error = copyinstr(path, ptr, sz, &len); 84 85 if (error) { 86 free(buf, M_TEMP); 87 return error; 88 } 89 90 if (*ptr != '/') { 91 free(buf, M_TEMP); 92 return EINVAL; 93 } 94 95 /* 96 * We know that there is a / somewhere in this pathname. 97 * Search backwards for it, to find the file's parent dir 98 * to see if it exists in the alternate tree. If it does, 99 * and we want to create a file (cflag is set). We don't 100 * need to worry about the root comparison in this case. 101 */ 102 103 if (cflag) { 104 for (cp = &ptr[len] - 1; *cp != '/'; cp--); 105 *cp = '\0'; 106 107 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 108 109 if ((error = namei(&nd)) != 0) { 110 free(buf, M_TEMP); 111 return error; 112 } 113 114 *cp = '/'; 115 } 116 else { 117 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 118 119 if ((error = namei(&nd)) != 0) { 120 free(buf, M_TEMP); 121 return error; 122 } 123 124 /* 125 * We now compare the vnode of the linux_root to the one 126 * vnode asked. If they resolve to be the same, then we 127 * ignore the match so that the real root gets used. 128 * This avoids the problem of traversing "../.." to find the 129 * root directory and never finding it, because "/" resolves 130 * to the emulation root directory. This is expensive :-( 131 */ 132 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path, 133 p); 134 135 if ((error = namei(&ndroot)) != 0) { 136 /* Cannot happen! */ 137 free(buf, M_TEMP); 138 NDFREE(&nd, NDF_ONLY_PNBUF); 139 vrele(nd.ni_vp); 140 return error; 141 } 142 143 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) { 144 goto bad; 145 } 146 147 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p)) 148 != 0) { 149 goto bad; 150 } 151 152 if (vat.va_fsid == vatroot.va_fsid && 153 vat.va_fileid == vatroot.va_fileid) { 154 error = ENOENT; 155 goto bad; 156 } 157 158 } 159 if (sgp == NULL) 160 *pbuf = buf; 161 else { 162 sz = &ptr[len] - buf; 163 *pbuf = stackgap_alloc(sgp, sz + 1); 164 if (*pbuf != NULL) 165 error = copyout(buf, *pbuf, sz); 166 else 167 error = ENAMETOOLONG; 168 free(buf, M_TEMP); 169 } 170 171 NDFREE(&nd, NDF_ONLY_PNBUF); 172 vrele(nd.ni_vp); 173 if (!cflag) { 174 NDFREE(&ndroot, NDF_ONLY_PNBUF); 175 vrele(ndroot.ni_vp); 176 } 177 return error; 178 179 bad: 180 NDFREE(&ndroot, NDF_ONLY_PNBUF); 181 vrele(ndroot.ni_vp); 182 NDFREE(&nd, NDF_ONLY_PNBUF); 183 vrele(nd.ni_vp); 184 free(buf, M_TEMP); 185 return error; 186 } 187