1 /* $NetBSD: devname.c,v 1.23 2019/02/18 20:27:20 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 Simon Burge.
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
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: devname.c,v 1.23 2019/02/18 20:27:20 christos Exp $");
34
35 #include "namespace.h"
36 #include "reentrant.h"
37 #include <sys/stat.h>
38
39 #include <cdbr.h>
40 #include <errno.h>
41 #include <fts.h>
42 #include <limits.h>
43 #include <paths.h>
44 #include <stdio.h>
45 #include <string.h>
46 #include <stdlib.h>
47
48 #ifdef __weak_alias
49 __weak_alias(devname_r,_devname_r)
50 #endif
51
52 static once_t db_opened = ONCE_INITIALIZER;
53 static struct cdbr *db;
54 static devmajor_t pts;
55
56 static void
devname_dbopen(void)57 devname_dbopen(void)
58 {
59 db = cdbr_open(_PATH_DEVCDB, CDBR_DEFAULT);
60 pts = getdevmajor("pts", S_IFCHR);
61 }
62
63 __CTASSERT(sizeof(dev_t) == 8);
64
65 static int
devname_dblookup(dev_t dev,mode_t type,char * path,size_t len)66 devname_dblookup(dev_t dev, mode_t type, char *path, size_t len)
67 {
68 const void *data;
69 size_t datalen;
70 uint8_t key[10];
71
72 le64enc(key, dev);
73 le16enc(key + 8, type);
74 if (cdbr_find(db, key, sizeof(key), &data, &datalen) != 0)
75 return ENOENT;
76 if (datalen <= sizeof(key))
77 return ENOENT;
78 if (memcmp(key, data, sizeof(key)) != 0)
79 return ENOENT;
80 data = (const char *)data + sizeof(key);
81 datalen -= sizeof(key);
82 if (memchr(data, '\0', datalen) != (const char *)data + datalen - 1)
83 return ENOENT;
84 if (datalen > len)
85 return ERANGE;
86 memcpy(path, data, datalen);
87 return 0;
88 }
89
90 static int
devname_ptslookup(dev_t dev,mode_t type,char * path,size_t len)91 devname_ptslookup(dev_t dev, mode_t type, char *path, size_t len)
92 {
93 int rv;
94
95 if (type != S_IFCHR || pts == NODEVMAJOR || major(dev) != pts)
96 return ENOENT;
97
98 rv = snprintf(path, len, "%s%d", &_PATH_DEV_PTS[sizeof(_PATH_DEV) - 1],
99 minor(dev));
100 if (rv < 0 || (size_t)rv >= len)
101 return ERANGE;
102 return 0;
103 }
104
105 static int
devname_fts(dev_t dev,mode_t type,char * path,size_t len)106 devname_fts(dev_t dev, mode_t type, char *path, size_t len)
107 {
108 FTS *ftsp;
109 FTSENT *fe;
110 static const char path_dev[] = _PATH_DEV;
111 static char * const dirs[2] = { __UNCONST(path_dev), NULL };
112 const size_t len_dev = strlen(path_dev);
113 int rv;
114
115 if ((ftsp = fts_open(dirs, FTS_NOCHDIR | FTS_PHYSICAL, NULL)) == NULL)
116 return ENOENT;
117
118 rv = ENOENT;
119 while ((fe = fts_read(ftsp)) != NULL) {
120 if (fe->fts_info != FTS_DEFAULT)
121 continue;
122 if (fe->fts_statp->st_rdev != dev)
123 continue;
124 if ((type & S_IFMT) != (fe->fts_statp->st_mode & S_IFMT))
125 continue;
126 if (strncmp(fe->fts_path, path_dev, len_dev))
127 continue;
128 if (strlcpy(path, fe->fts_path + len_dev, len) < len) {
129 rv = 0;
130 break;
131 }
132 }
133
134 fts_close(ftsp);
135 return rv;
136 }
137
138 int
devname_r(dev_t dev,mode_t type,char * path,size_t len)139 devname_r(dev_t dev, mode_t type, char *path, size_t len)
140 {
141 int rv;
142
143 thr_once(&db_opened, devname_dbopen);
144
145 if (db != NULL) {
146 rv = devname_dblookup(dev, type, path, len);
147 if (rv == 0 || rv == ERANGE)
148 return rv;
149 }
150
151 rv = devname_ptslookup(dev, type, path, len);
152 if (rv == 0 || rv == ERANGE)
153 return rv;
154
155 if (db != NULL)
156 return ENOENT;
157 rv = devname_fts(dev, type, path, len);
158 return rv;
159 }
160
161 char *
devname(dev_t dev,mode_t type)162 devname(dev_t dev, mode_t type)
163 {
164 static char path[PATH_MAX];
165
166 return devname_r(dev, type, path, sizeof(path)) == 0 ? path : NULL;
167 }
168