The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/i386/ibcs2/ibcs2_util.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: src/sys/i386/ibcs2/ibcs2_util.c,v 1.17.4.1 2005/01/31 23:26:03 imp Exp $");
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/namei.h>
   38 #include <sys/malloc.h>
   39 #include <sys/vnode.h>
   40 
   41 #include <i386/ibcs2/ibcs2_util.h>
   42 
   43 
   44 const char      ibcs2_emul_path[] = "/compat/ibcs2";
   45 
   46 /*
   47  * Search an alternate path before passing pathname arguments on
   48  * to system calls. Useful for keeping a separate '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 ibcs2_emul_find(td, sgp, prefix, path, pbuf, cflag)
   56         struct thread    *td;
   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, td);
  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, td);
  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 ibcs2_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, ibcs2_emul_path,
  135                        td);
  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, td->td_ucred, td)) != 0) {
  146                         goto done;
  147                 }
  148 
  149                 if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, td->td_ucred, td))
  150                     != 0) {
  151                         goto done;
  152                 }
  153 
  154                 if (vat.va_fsid == vatroot.va_fsid &&
  155                     vat.va_fileid == vatroot.va_fileid) {
  156                         error = ENOENT;
  157                         goto done;
  158                 }
  159 
  160         }
  161         if (sgp == NULL)
  162                 *pbuf = buf;
  163         else {
  164                 sz = &ptr[len] - buf;
  165                 if ((*pbuf = stackgap_alloc(sgp, sz + 1)) != NULL)
  166                         error = copyout(buf, *pbuf, sz);
  167                 else
  168                         error = ENAMETOOLONG;
  169                 free(buf, M_TEMP);
  170         }
  171 
  172 
  173 done:
  174         NDFREE(&nd, NDF_ONLY_PNBUF);
  175         vrele(nd.ni_vp);
  176         if (!cflag) {
  177                 NDFREE(&ndroot, NDF_ONLY_PNBUF);
  178                 vrele(ndroot.ni_vp);
  179         }
  180         return error;
  181 }

Cache object: c20d04023549320196ef003d2b90ebd4


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.