util/opendev.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*      $OpenBSD: opendev.c,v 1.7 2002/06/09 22:18:43 fgsch Exp $       */
  26
  27 /*
  28  * Copyright (c) 2000, Todd C. Miller.  All rights reserved.
  29  * Copyright (c) 1996, Jason Downs.  All rights reserved.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
  41  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  42  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  43  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
  44  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  45  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  46  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  47  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  */
  52
  53 #include <ctype.h>
  54 #include <errno.h>
  55 #include <fcntl.h>
  56 #include <limits.h>
  57 #include <paths.h>
  58 #include <stdio.h>
  59 #include <string.h>
  60
  61 #include "util.h"
  62
  63 int
  64 opendev(path, oflags, dflags, realpath)
  65         char *path;
  66         int oflags;
  67         int dflags;
  68         char **realpath;
  69 {
  70         int fd;
  71         char *slash, *prefix;
  72         static char namebuf[PATH_MAX];
  73
  74         /* Initial state */
  75         if (realpath)
  76                 *realpath = path;
  77         fd = -1;
  78         errno = ENOENT;
  79
  80         if (dflags & OPENDEV_BLCK)
  81                 prefix = "";                    /* block device */
  82         else
  83                 prefix = "r";                   /* character device */
  84
  85         if ((slash = strchr(path, '/')))
  86                 fd = open(path, oflags);
  87         else if (dflags & OPENDEV_PART) {
  88                 if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
  89                     _PATH_DEV, prefix, path) < sizeof(namebuf)) {
  90                         char *slice;
  91                         while ((slice = strrchr(namebuf, 's')) &&
  92                             isdigit(*(slice-1))) *slice = '\0';
  93                         fd = open(namebuf, oflags);
  94                         if (realpath)
  95                                 *realpath = namebuf;
  96                 } else
  97                         errno = ENAMETOOLONG;
  98         }
  99         if (!slash && fd == -1 && errno == ENOENT) {
 100                 if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
 101                     _PATH_DEV, prefix, path) < sizeof(namebuf)) {
 102                         fd = open(namebuf, oflags);
 103                         if (realpath)
 104                                 *realpath = namebuf;
 105                 } else
 106                         errno = ENAMETOOLONG;
 107         }
 108         return (fd);
 109 }