lib/libutil/getdiskrawname.c

   1 /*      $NetBSD: getdiskrawname.c,v 1.5 2014/09/17 23:54:42 christos Exp $      */
   2
   3 /*-
   4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Christos Zoulas.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 #include <sys/cdefs.h>
  32 __RCSID("$NetBSD: getdiskrawname.c,v 1.5 2014/09/17 23:54:42 christos Exp $");
  33
  34 #include <sys/stat.h>
  35
  36 #include <stdio.h>
  37 #include <string.h>
  38 #include <errno.h>
  39 #include <util.h>
  40 #include <limits.h>
  41 #include <unistd.h>
  42
  43 static const char *
  44 resolve_link(char *buf, size_t bufsiz, const char *name)
  45 {
  46         const char *dp;
  47         size_t nlen;
  48         ssize_t dlen;
  49
  50         dlen = readlink(name, buf, bufsiz - 1);
  51         if (dlen == -1)
  52                 return name;
  53
  54         buf[dlen] = '\0';
  55
  56         if (buf[0] != '/') {
  57                 dp = strrchr(name, '/');
  58                 if (dp != NULL) {
  59                         nlen = dp - name + 1;
  60                         if (nlen + 1 > bufsiz)
  61                                 return NULL;
  62                         if (nlen + dlen + 1 > bufsiz)
  63                                 return NULL;
  64
  65                         memmove(buf + nlen, buf, (size_t)dlen + 1);
  66                         memcpy(buf, name, nlen);
  67                 }
  68         }
  69
  70         return buf;
  71 }
  72
  73 const char *
  74 getdiskrawname(char *buf, size_t bufsiz, const char *name)
  75 {
  76         const char *dp;
  77         struct stat st;
  78         char dest[PATH_MAX];
  79
  80         if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
  81                 errno = EINVAL;
  82                 return NULL;
  83         }
  84
  85         dp = strrchr(name, '/');
  86
  87         if (stat(name, &st) == -1)
  88                 return NULL;
  89
  90         if (!S_ISBLK(st.st_mode)) {
  91                 errno = EFTYPE;
  92                 return NULL;
  93         }
  94
  95         if (dp != NULL)
  96                 (void)snprintf(buf, bufsiz, "%.*s/r%s", (int)(dp - name), name, dp + 1);
  97         else
  98                 (void)snprintf(buf, bufsiz, "r%s", name);
  99
 100         return buf;
 101 }
 102
 103 const char *
 104 getdiskcookedname(char *buf, size_t bufsiz, const char *name)
 105 {
 106         const char *dp;
 107         struct stat st;
 108         char dest[PATH_MAX];
 109
 110         if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
 111                 errno = EINVAL;
 112                 return NULL;
 113         }
 114
 115         dp = strrchr(name, '/');
 116
 117         if ((dp != NULL && dp[1] != 'r') || (dp == NULL && name[0] != 'r')) {
 118                 errno = EINVAL;
 119                 return NULL;
 120         }
 121
 122         if (stat(name, &st) == -1)
 123                 return NULL;
 124
 125         if (!S_ISCHR(st.st_mode)) {
 126                 errno = EFTYPE;
 127                 return NULL;
 128         }
 129
 130         if (dp != NULL)
 131                 (void)snprintf(buf, bufsiz, "%.*s/%s", (int)(dp - name), name, dp + 2);
 132         else
 133                 (void)snprintf(buf, bufsiz, "%s", name + 1);
 134
 135         return buf;
 136 }