util/opendev.c

   1 /*
   2  * Copyright (c) 2000, Todd C. Miller.  All rights reserved.
   3  * Copyright (c) 1996, Jason Downs.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
  15  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  17  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
  18  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  20  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  21  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <ctype.h>
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <limits.h>
  31 #include <paths.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34
  35 #include "util.h"
  36
  37 int
  38 opendev(path, oflags, dflags, realpath)
  39         char *path;
  40         int oflags;
  41         int dflags;
  42         char **realpath;
  43 {
  44         int fd;
  45         char *slash, *prefix;
  46         static char namebuf[PATH_MAX];
  47
  48         /* Initial state */
  49         if (realpath)
  50                 *realpath = path;
  51         fd = -1;
  52         errno = ENOENT;
  53
  54         if (dflags & OPENDEV_BLCK)
  55                 prefix = "";                    /* block device */
  56         else
  57                 prefix = "r";                   /* character device */
  58
  59         if ((slash = strchr(path, '/')))
  60                 fd = open(path, oflags);
  61         else if (dflags & OPENDEV_PART) {
  62                 if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
  63                     _PATH_DEV, prefix, path) < sizeof(namebuf)) {
  64                         char *slice;
  65                         while ((slice = strrchr(namebuf, 's')) &&
  66                             isdigit(*(slice-1))) *slice = '\0';
  67                         fd = open(namebuf, oflags);
  68                         if (realpath)
  69                                 *realpath = namebuf;
  70                 } else
  71                         errno = ENAMETOOLONG;
  72         }
  73         if (!slash && fd == -1 && errno == ENOENT) {
  74                 if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
  75                     _PATH_DEV, prefix, path) < sizeof(namebuf)) {
  76                         fd = open(namebuf, oflags);
  77                         if (realpath)
  78                                 *realpath = namebuf;
  79                 } else
  80                         errno = ENAMETOOLONG;
  81         }
  82         return (fd);
  83 }