1 #include "lookup.h"
2 #include "stdio_impl.h"
3 #include <ctype.h>
4 #include <errno.h>
5 #include <string.h>
6 #include <stdlib.h>
7 #include <netinet/in.h>
8
__get_resolv_conf(struct resolvconf * conf,char * search,size_t search_sz)9 int __get_resolv_conf(struct resolvconf *conf, char *search, size_t search_sz)
10 {
11 char line[256];
12 unsigned char _buf[256];
13 FILE *f, _f;
14 int nns = 0;
15
16 conf->ndots = 1;
17 conf->timeout = 5;
18 conf->attempts = 2;
19 if (search) *search = 0;
20
21 f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
22 if (!f) switch (errno) {
23 case ENOENT:
24 case ENOTDIR:
25 case EACCES:
26 goto no_resolv_conf;
27 default:
28 return -1;
29 }
30
31 while (fgets(line, sizeof line, f)) {
32 char *p, *z;
33 if (!strchr(line, '\n') && !feof(f)) {
34 /* Ignore lines that get truncated rather than
35 * potentially misinterpreting them. */
36 int c;
37 do c = getc(f);
38 while (c != '\n' && c != EOF);
39 continue;
40 }
41 if (!strncmp(line, "options", 7) && isspace(line[7])) {
42 p = strstr(line, "ndots:");
43 if (p && isdigit(p[6])) {
44 p += 6;
45 unsigned long x = strtoul(p, &z, 10);
46 if (z != p) conf->ndots = x > 15 ? 15 : x;
47 }
48 p = strstr(line, "attempts:");
49 if (p && isdigit(p[9])) {
50 p += 9;
51 unsigned long x = strtoul(p, &z, 10);
52 if (z != p) conf->attempts = x > 10 ? 10 : x;
53 }
54 p = strstr(line, "timeout:");
55 if (p && (isdigit(p[8]) || p[8]=='.')) {
56 p += 8;
57 unsigned long x = strtoul(p, &z, 10);
58 if (z != p) conf->timeout = x > 60 ? 60 : x;
59 }
60 continue;
61 }
62 if (!strncmp(line, "nameserver", 10) && isspace(line[10])) {
63 if (nns >= MAXNS) continue;
64 for (p=line+11; isspace(*p); p++);
65 for (z=p; *z && !isspace(*z); z++);
66 *z=0;
67 if (__lookup_ipliteral(conf->ns+nns, p, AF_UNSPEC) > 0)
68 nns++;
69 continue;
70 }
71
72 if (!search) continue;
73 if ((strncmp(line, "domain", 6) && strncmp(line, "search", 6))
74 || !isspace(line[6]))
75 continue;
76 for (p=line+7; isspace(*p); p++);
77 size_t l = strlen(p);
78 /* This can never happen anyway with chosen buffer sizes. */
79 if (l >= search_sz) continue;
80 memcpy(search, p, l+1);
81 }
82
83 __fclose_ca(f);
84
85 no_resolv_conf:
86 if (!nns) {
87 __lookup_ipliteral(conf->ns, "127.0.0.1", AF_UNSPEC);
88 nns = 1;
89 }
90
91 conf->nns = nns;
92
93 return 0;
94 }
95