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(td, sgp, path, pbuf, cflag) 54 struct thread *td; 55 caddr_t *sgp; /* Pointer to stackgap memory */ 56 char *path; 57 char **pbuf; 58 int cflag; 59 { 60 char *newpath; 61 size_t sz; 62 int error; 63 64 error = linux_emul_convpath(td, path, (sgp == NULL) ? UIO_SYSSPACE : 65 UIO_USERSPACE, &newpath, cflag); 66 if (newpath == NULL) 67 return (error); 68 69 if (sgp == NULL) { 70 *pbuf = newpath; 71 return (error); 72 } 73 74 sz = strlen(newpath); 75 *pbuf = stackgap_alloc(sgp, sz + 1); 76 if (*pbuf != NULL) 77 error = copyout(newpath, *pbuf, sz + 1); 78 else 79 error = ENAMETOOLONG; 80 free(newpath, M_TEMP); 81 82 return (error); 83 } 84 85 int 86 linux_emul_convpath(td, path, pathseg, pbuf, cflag) 87 struct thread *td; 88 char *path; 89 enum uio_seg pathseg; 90 char **pbuf; 91 int cflag; 92 { 93 struct nameidata nd; 94 struct nameidata ndroot; 95 struct vattr vat; 96 struct vattr vatroot; 97 int error; 98 const char *prefix; 99 char *ptr, *buf, *cp; 100 size_t len, sz; 101 102 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 103 *pbuf = buf; 104 105 prefix = linux_emul_path; 106 for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++) 107 continue; 108 sz = MAXPATHLEN - (ptr - buf); 109 110 if (pathseg == UIO_SYSSPACE) 111 error = copystr(path, ptr, sz, &len); 112 else 113 error = copyinstr(path, ptr, sz, &len); 114 115 if (error) { 116 *pbuf = NULL; 117 free(buf, M_TEMP); 118 return error; 119 } 120 121 if (*ptr != '/') { 122 error = EINVAL; 123 goto keeporig; 124 } 125 126 /* 127 * We know that there is a / somewhere in this pathname. 128 * Search backwards for it, to find the file's parent dir 129 * to see if it exists in the alternate tree. If it does, 130 * and we want to create a file (cflag is set). We don't 131 * need to worry about the root comparison in this case. 132 */ 133 134 if (cflag) { 135 for (cp = &ptr[len] - 1; *cp != '/'; cp--); 136 *cp = '\0'; 137 138 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 139 error = namei(&nd); 140 *cp = '/'; 141 if (error != 0) 142 goto keeporig; 143 } 144 else { 145 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 146 147 if ((error = namei(&nd)) != 0) 148 goto keeporig; 149 150 /* 151 * We now compare the vnode of the linux_root to the one 152 * vnode asked. If they resolve to be the same, then we 153 * ignore the match so that the real root gets used. 154 * This avoids the problem of traversing "../.." to find the 155 * root directory and never finding it, because "/" resolves 156 * to the emulation root directory. This is expensive :-( 157 */ 158 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path, 159 td); 160 161 if ((error = namei(&ndroot)) != 0) { 162 /* Cannot happen! */ 163 NDFREE(&nd, NDF_ONLY_PNBUF); 164 vrele(nd.ni_vp); 165 goto keeporig; 166 } 167 168 if ((error = VOP_GETATTR(nd.ni_vp, &vat, td->td_ucred, td)) != 0) { 169 goto bad; 170 } 171 172 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, td->td_ucred, td)) 173 != 0) { 174 goto bad; 175 } 176 177 if (vat.va_fsid == vatroot.va_fsid && 178 vat.va_fileid == vatroot.va_fileid) { 179 error = ENOENT; 180 goto bad; 181 } 182 183 } 184 185 NDFREE(&nd, NDF_ONLY_PNBUF); 186 vrele(nd.ni_vp); 187 if (!cflag) { 188 NDFREE(&ndroot, NDF_ONLY_PNBUF); 189 vrele(ndroot.ni_vp); 190 } 191 return error; 192 193 bad: 194 NDFREE(&ndroot, NDF_ONLY_PNBUF); 195 vrele(ndroot.ni_vp); 196 NDFREE(&nd, NDF_ONLY_PNBUF); 197 vrele(nd.ni_vp); 198 keeporig: 199 /* Keep the original path; copy it back to the start of the buffer. */ 200 bcopy(ptr, buf, len); 201 return error; 202 } 203