1 /***
2   This file is part of avahi.
3 
4   avahi is free software; you can redistribute it and/or modify it
5   under the terms of the GNU Lesser General Public License as
6   published by the Free Software Foundation; either version 2.1 of the
7   License, or (at your option) any later version.
8 
9   avahi is distributed in the hope that it will be useful, but WITHOUT
10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11   or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
12   Public License for more details.
13 
14   You should have received a copy of the GNU Lesser General Public
15   License along with avahi; if not, write to the Free Software
16   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
17   USA.
18 ***/
19 
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23 
24 #include <stdlib.h>
25 #include <assert.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <ctype.h>
29 #include <sys/utsname.h>
30 #include <stdio.h>
31 
32 #include "avahi-common/avahi-malloc.h"
33 
34 #include "log.h"
35 #include "domain-util.h"
36 #include "util.h"
37 
strip_bad_chars(char * s)38 static void strip_bad_chars(char *s) {
39     char *p, *d;
40 
41     s[strcspn(s, ".")] = 0;
42 
43     for (p = s, d = s; *p; p++)
44         if ((*p >= 'a' && *p <= 'z') ||
45             (*p >= 'A' && *p <= 'Z') ||
46             (*p >= '0' && *p <= '9') ||
47             *p == '-')
48             *(d++) = *p;
49 
50     *d = 0;
51 }
52 
53 #ifdef __linux__
load_lsb_distrib_id(char * ret_s,size_t size)54 static int load_lsb_distrib_id(char *ret_s, size_t size) {
55     FILE *f;
56 
57     assert(ret_s);
58     assert(size > 0);
59 
60     if (!(f = fopen("/etc/lsb-release", "r")))
61         return -1;
62 
63     while (!feof(f)) {
64         char ln[256], *p;
65 
66         if (!fgets(ln, sizeof(ln), f))
67             break;
68 
69         if (strncmp(ln, "DISTRIB_ID=", 11))
70             continue;
71 
72         p = ln + 11;
73         p += strspn(p, "\"");
74         p[strcspn(p, "\"")] = 0;
75 
76         snprintf(ret_s, size, "%s", p);
77 
78         fclose(f);
79         return 0;
80     }
81 
82     fclose(f);
83     return -1;
84 }
85 #endif
86 
avahi_get_host_name(char * ret_s,size_t size)87 char *avahi_get_host_name(char *ret_s, size_t size) {
88     assert(ret_s);
89     assert(size > 0);
90 
91     if (gethostname(ret_s, size) >= 0) {
92         ret_s[size-1] = 0;
93         strip_bad_chars(ret_s);
94     } else
95         *ret_s = 0;
96 
97     if (strcmp(ret_s, "localhost") == 0 || strncmp(ret_s, "localhost.", 10) == 0) {
98         *ret_s = 0;
99         avahi_log_warn("System host name is set to 'localhost'. This is not a suitable mDNS host name, looking for alternatives.");
100     }
101 
102     if (*ret_s == 0) {
103         /* No hostname was set, so let's take the OS name */
104 
105 #ifdef __linux__
106 
107         /* Try LSB distribution name first */
108         if (load_lsb_distrib_id(ret_s, size) >= 0) {
109             strip_bad_chars(ret_s);
110             avahi_strdown(ret_s);
111         }
112 
113         if (*ret_s == 0)
114 #endif
115 
116         {
117             /* Try uname() second */
118             struct utsname utsname;
119 
120             if (uname(&utsname) >= 0) {
121                 snprintf(ret_s, size, "%s", utsname.sysname);
122                 strip_bad_chars(ret_s);
123                 avahi_strdown(ret_s);
124             }
125 
126             /* Give up */
127             if (*ret_s == 0)
128                 snprintf(ret_s, size, "unnamed");
129         }
130     }
131 
132     if (size >= AVAHI_LABEL_MAX)
133 	ret_s[AVAHI_LABEL_MAX-1] = 0;
134 
135     return ret_s;
136 }
137 
avahi_get_host_name_strdup(void)138 char *avahi_get_host_name_strdup(void) {
139     char t[AVAHI_DOMAIN_NAME_MAX];
140 
141     if (!(avahi_get_host_name(t, sizeof(t))))
142         return NULL;
143 
144     return avahi_strdup(t);
145 }
146 
avahi_binary_domain_cmp(const char * a,const char * b)147 int avahi_binary_domain_cmp(const char *a, const char *b) {
148     assert(a);
149     assert(b);
150 
151     if (a == b)
152         return 0;
153 
154     for (;;) {
155         char ca[AVAHI_LABEL_MAX], cb[AVAHI_LABEL_MAX], *p;
156         int r;
157 
158         p = avahi_unescape_label(&a, ca, sizeof(ca));
159         assert(p);
160         p = avahi_unescape_label(&b, cb, sizeof(cb));
161         assert(p);
162 
163         if ((r = strcmp(ca, cb)))
164             return r;
165 
166         if (!*a && !*b)
167             return 0;
168     }
169 }
170 
avahi_domain_ends_with(const char * domain,const char * suffix)171 int avahi_domain_ends_with(const char *domain, const char *suffix) {
172     assert(domain);
173     assert(suffix);
174 
175     for (;;) {
176         char dummy[AVAHI_LABEL_MAX], *r;
177 
178         if (*domain == 0)
179             return 0;
180 
181         if (avahi_domain_equal(domain, suffix))
182             return 1;
183 
184         r = avahi_unescape_label(&domain, dummy, sizeof(dummy));
185         assert(r);
186     }
187 }
188 
189