1 /* $NetBSD: compat_util.c,v 1.14 1999/04/27 15:42:37 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1994 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas and Frank van der Linden. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/namei.h> 42 #include <sys/proc.h> 43 #include <sys/file.h> 44 #include <sys/stat.h> 45 #include <sys/filedesc.h> 46 #include <sys/exec.h> 47 #include <sys/ioctl.h> 48 #include <sys/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/vnode.h> 51 #include <sys/syslog.h> 52 #include <sys/mount.h> 53 54 #include <vm/vm_param.h> 55 56 #include <compat/common/compat_util.h> 57 58 /* 59 * Search an alternate path before passing pathname arguments on 60 * to system calls. Useful for keeping a separate 'emulation tree'. 61 * 62 * If cflag is set, we check if an attempt can be made to create 63 * the named file, i.e. we check if the directory it should 64 * be in exists. 65 * 66 * In case of success, emul_find returns 0: 67 * If sgp is provided, the path is in user space, and pbuf gets 68 * allocated in user space (in the stackgap). Otherwise the path 69 * is already in kernel space and a kernel buffer gets allocated 70 * and returned in pbuf, that must be freed by the user. 71 * In case of error, the error number is returned and *pbuf = path. 72 */ 73 int 74 emul_find(p, sgp, prefix, path, pbuf, cflag) 75 struct proc *p; 76 caddr_t *sgp; /* Pointer to stackgap memory */ 77 const char *prefix; 78 const char *path; 79 const char **pbuf; 80 int cflag; 81 { 82 struct nameidata nd; 83 struct nameidata ndroot; 84 struct vattr vat; 85 struct vattr vatroot; 86 int error; 87 char *ptr, *buf, *cp; 88 const char *pr; 89 size_t sz, len; 90 91 buf = (char *)malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 92 *pbuf = path; 93 94 for (ptr = buf, pr = prefix; (*ptr = *pr) != '\0'; ptr++, pr++) 95 continue; 96 97 sz = MAXPATHLEN - (ptr - buf); 98 99 /* 100 * If sgp is not given then the path is already in kernel space 101 */ 102 if (sgp == NULL) 103 error = copystr(path, ptr, sz, &len); 104 else 105 error = copyinstr(path, ptr, sz, &len); 106 107 if (error) 108 goto bad; 109 110 if (*ptr != '/') { 111 error = EINVAL; 112 goto bad; 113 } 114 115 /* 116 * We provide an escape method, so that the user can 117 * always specify the real root. If the path is prefixed 118 * by /../ we kill the alternate search 119 */ 120 if (ptr[1] == '.' && ptr[2] == '.' && ptr[3] == '/') { 121 len -= 3; 122 (void)memcpy(buf, &ptr[3], len); 123 ptr = buf; 124 goto good; 125 } 126 127 /* 128 * We know that there is a / somewhere in this pathname. 129 * Search backwards for it, to find the file's parent dir 130 * to see if it exists in the alternate tree. If it does, 131 * and we want to create a file (cflag is set). We don't 132 * need to worry about the root comparison in this case. 133 */ 134 135 if (cflag) { 136 for (cp = &ptr[len] - 1; *cp != '/'; cp--) 137 ; 138 *cp = '\0'; 139 140 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 141 142 if ((error = namei(&nd)) != 0) 143 goto bad; 144 145 *cp = '/'; 146 } 147 else { 148 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 149 150 if ((error = namei(&nd)) != 0) 151 goto bad; 152 153 /* 154 * We now compare the vnode of the emulation root to the one 155 * vnode asked. If they resolve to be the same, then we 156 * ignore the match so that the real root gets used. 157 * This avoids the problem of traversing "../.." to find the 158 * root directory and never finding it, because "/" resolves 159 * to the emulation root directory. This is expensive :-( 160 */ 161 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, p); 162 163 if ((error = namei(&ndroot)) != 0) 164 goto bad2; 165 166 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) 167 goto bad3; 168 169 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p)) 170 != 0) 171 goto bad3; 172 173 if (vat.va_fsid == vatroot.va_fsid && 174 vat.va_fileid == vatroot.va_fileid) { 175 error = ENOENT; 176 goto bad3; 177 } 178 } 179 180 vrele(nd.ni_vp); 181 if (!cflag) 182 vrele(ndroot.ni_vp); 183 184 good: 185 if (sgp == NULL) 186 *pbuf = buf; 187 else { 188 sz = &ptr[len] - buf; 189 *pbuf = stackgap_alloc(sgp, sz + 1); 190 if ((error = copyout(buf, (void *)*pbuf, sz)) != 0) { 191 *pbuf = path; 192 return error; 193 } 194 free(buf, M_TEMP); 195 } 196 return 0; 197 198 bad3: 199 vrele(ndroot.ni_vp); 200 bad2: 201 vrele(nd.ni_vp); 202 bad: 203 free(buf, M_TEMP); 204 return error; 205 } 206 207 /* 208 * Translate one set of flags to another, based on the entries in 209 * the given table. If 'leftover' is specified, it is filled in 210 * with any flags which could not be translated. 211 */ 212 unsigned long 213 emul_flags_translate(const struct emul_flags_xtab *tab, 214 unsigned long in, unsigned long *leftover) 215 { 216 unsigned long out; 217 218 for (out = 0; tab->omask != 0; tab++) { 219 if ((in & tab->omask) == tab->oval) { 220 in &= ~tab->omask; 221 out |= tab->nval; 222 } 223 } 224 if (leftover != NULL) 225 *leftover = in; 226 return (out); 227 } 228 229 caddr_t 230 stackgap_init(e) 231 struct emul *e; 232 { 233 234 #define szsigcode ((caddr_t)(e->e_esigcode - e->e_sigcode)) 235 return STACKGAPBASE; 236 #undef szsigcode 237 } 238 239 240 void * 241 stackgap_alloc(sgp, sz) 242 caddr_t *sgp; 243 size_t sz; 244 { 245 void *p = (void *) *sgp; 246 247 *sgp += ALIGN(sz); 248 return p; 249 } 250 251 void 252 compat_offseterr(vp, msg) 253 struct vnode *vp; 254 char *msg; 255 { 256 struct mount *mp; 257 258 mp = vp->v_mount; 259 260 log(LOG_ERR, "%s: dir offset too large on fs %s (mounted from %s)\n", 261 msg, mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname); 262 uprintf("%s: dir offset too large for emulated program\n", msg); 263 } 264