util/opendev.c

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