usr/src/lib/libc/port/gen/fattach.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  * Attach a STREAMS or door based file descriptor to an object in the file
  34  * system name space.
  35  */
  36
  37 #pragma weak _fattach = fattach
  38
  39 #include "lint.h"
  40 #include <sys/types.h>
  41 #include <errno.h>
  42 #include <stdio.h>
  43 #include <stropts.h>
  44 #include <sys/door.h>
  45 #include <sys/fs/namenode.h>
  46 #include <sys/mount.h>
  47 #include <unistd.h>
  48 #include <string.h>
  49 #include "libc.h"
  50
  51 int
  52 fattach(int fildes, const char *path)
  53 {
  54         struct namefd  namefdp;
  55         struct door_info dinfo;
  56         int     s;
  57         char buf[MAXPATHLEN];
  58
  59         /* Only STREAMS and doors allowed to be mounted */
  60         if ((s = isastream(fildes)) == 1 || __door_info(fildes, &dinfo) == 0) {
  61                 namefdp.fd = fildes;
  62                 if (path == NULL || *path == '\0') {
  63                         errno = ENOENT;
  64                         return (-1);
  65                 } else if (*path != '/') {
  66                         /*
  67                          * The mount point must be an absolute path.
  68                          */
  69                         if (getcwd(buf, sizeof (buf)) == NULL) {
  70                                 /* errno already set */
  71                                 return (-1);
  72                         }
  73                         /*
  74                          * The kernel will truncate the path if it would have
  75                          * turned into something more than MAXPATHLEN bytes.
  76                          * So we do the same here.
  77                          */
  78                         if (strlcat(buf, "/",  sizeof (buf)) >= sizeof (buf) ||
  79                             strlcat(buf, path, sizeof (buf)) >= sizeof (buf)) {
  80                                 errno = ENAMETOOLONG;
  81                                 return (-1);
  82                         }
  83                         path = buf;
  84                 }
  85                 return (mount(NULL, path, MS_DATA|MS_NOMNTTAB,
  86                     (const char *)"namefs", (char *)&namefdp,
  87                     sizeof (struct namefd), NULL, 0));
  88         } else if (s == 0) {
  89                 /* Not a STREAM */
  90                 errno = EINVAL;
  91                 return (-1);
  92         } else {
  93                 /* errno already set */
  94                 return (-1);
  95         }
  96 }