1 /* $NetBSD: compat_util.c,v 1.7 1997/10/10 01:47:00 fvdl Exp $ */ 2 3 /* 4 * Copyright (c) 1994 Christos Zoulas 5 * Copyright (c) 1995 Frank van der Linden 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 */ 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/namei.h> 35 #include <sys/proc.h> 36 #include <sys/file.h> 37 #include <sys/stat.h> 38 #include <sys/filedesc.h> 39 #include <sys/exec.h> 40 #include <sys/ioctl.h> 41 #include <sys/kernel.h> 42 #include <sys/malloc.h> 43 #include <sys/vnode.h> 44 #include <sys/syslog.h> 45 #include <sys/mount.h> 46 47 #include <vm/vm_param.h> 48 49 #include <compat/common/compat_util.h> 50 51 /* 52 * Search an alternate path before passing pathname arguments on 53 * to system calls. Useful for keeping a separate 'emulation tree'. 54 * 55 * If cflag is set, we check if an attempt can be made to create 56 * the named file, i.e. we check if the directory it should 57 * be in exists. 58 */ 59 int 60 emul_find(p, sgp, prefix, path, pbuf, cflag) 61 struct proc *p; 62 caddr_t *sgp; /* Pointer to stackgap memory */ 63 const char *prefix; 64 char *path; 65 char **pbuf; 66 int cflag; 67 { 68 struct nameidata nd; 69 struct nameidata ndroot; 70 struct vattr vat; 71 struct vattr vatroot; 72 int error; 73 char *ptr, *buf, *cp; 74 const char *pr; 75 size_t sz, len; 76 77 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 78 *pbuf = path; 79 80 for (ptr = buf, pr = prefix; (*ptr = *pr) != '\0'; ptr++, pr++) 81 continue; 82 83 sz = MAXPATHLEN - (ptr - buf); 84 85 /* 86 * If sgp is not given then the path is already in kernel space 87 */ 88 if (sgp == NULL) 89 error = copystr(path, ptr, sz, &len); 90 else 91 error = copyinstr(path, ptr, sz, &len); 92 93 if (error) 94 goto bad; 95 96 if (*ptr != '/') { 97 error = EINVAL; 98 goto bad; 99 } 100 101 /* 102 * We know that there is a / somewhere in this pathname. 103 * Search backwards for it, to find the file's parent dir 104 * to see if it exists in the alternate tree. If it does, 105 * and we want to create a file (cflag is set). We don't 106 * need to worry about the root comparison in this case. 107 */ 108 109 if (cflag) { 110 for (cp = &ptr[len] - 1; *cp != '/'; cp--) 111 ; 112 *cp = '\0'; 113 114 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 115 116 if ((error = namei(&nd)) != 0) 117 goto bad; 118 119 *cp = '/'; 120 } 121 else { 122 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p); 123 124 if ((error = namei(&nd)) != 0) 125 goto bad; 126 127 /* 128 * We now compare the vnode of the emulation root to the one 129 * vnode asked. If they resolve to be the same, then we 130 * ignore the match so that the real root gets used. 131 * This avoids the problem of traversing "../.." to find the 132 * root directory and never finding it, because "/" resolves 133 * to the emulation root directory. This is expensive :-( 134 */ 135 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, p); 136 137 if ((error = namei(&ndroot)) != 0) 138 goto bad2; 139 140 if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) 141 goto bad3; 142 143 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p)) 144 != 0) 145 goto bad3; 146 147 if (vat.va_fsid == vatroot.va_fsid && 148 vat.va_fileid == vatroot.va_fileid) { 149 error = ENOENT; 150 goto bad3; 151 } 152 } 153 if (sgp == NULL) 154 *pbuf = buf; 155 else { 156 sz = &ptr[len] - buf; 157 *pbuf = stackgap_alloc(sgp, sz + 1); 158 error = copyout(buf, *pbuf, sz); 159 free(buf, M_TEMP); 160 } 161 162 vrele(nd.ni_vp); 163 if (!cflag) 164 vrele(ndroot.ni_vp); 165 return error; 166 167 bad3: 168 vrele(ndroot.ni_vp); 169 bad2: 170 vrele(nd.ni_vp); 171 bad: 172 free(buf, M_TEMP); 173 return error; 174 } 175 176 caddr_t 177 stackgap_init(e) 178 struct emul *e; 179 { 180 181 #define szsigcode ((caddr_t)(e->e_esigcode - e->e_sigcode)) 182 return STACKGAPBASE; 183 #undef szsigcode 184 } 185 186 187 void * 188 stackgap_alloc(sgp, sz) 189 caddr_t *sgp; 190 size_t sz; 191 { 192 void *p = (void *) *sgp; 193 194 *sgp += ALIGN(sz); 195 return p; 196 } 197 198 void 199 compat_offseterr(vp, msg) 200 struct vnode *vp; 201 char *msg; 202 { 203 struct mount *mp; 204 205 mp = vp->v_mount; 206 207 log(LOG_ERR, "%s: dir offset too large on fs %s (mounted from %s)\n", 208 msg, mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname); 209 uprintf("%s: dir offset too large for emulated program\n", msg); 210 } 211