samba-tool: Add a gpo command for removing VGP Startup Scripts Group Policy
[samba.git] / libcli / dns / resolvconf.c
1 /*
2  *  Unix SMB/CIFS implementation.
3  *  Internal DNS query structures
4  *  Copyright (C) Volker Lendecke 2018
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 3 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19
20 #include "replace.h"
21 #include <stdio.h>
22 #include <errno.h>
23 #include "libcli/dns/resolvconf.h"
24 #include "lib/util/memory.h"
25
26 int parse_resolvconf_fp(
27         FILE *fp,
28         TALLOC_CTX *mem_ctx,
29         char ***pnameservers,
30         size_t *pnum_nameservers)
31 {
32         char *line = NULL;
33         size_t len = 0;
34         char **nameservers = NULL;
35         size_t num_nameservers = 0;
36         int ret = 0;
37
38         while (true) {
39                 char *saveptr = NULL, *option = NULL, *ns = NULL;
40                 char **tmp = NULL;
41                 ssize_t n = 0;
42
43                 n = getline(&line, &len, fp);
44                 if (n < 0) {
45                         if (!feof(fp)) {
46                                 /* real error */
47                                 ret = errno;
48                         }
49                         break;
50                 }
51                 if ((n > 0) && (line[n-1] == '\n')) {
52                         line[n-1] = '\0';
53                 }
54
55                 if ((line[0] == '#') || (line[0] == ';')) {
56                         continue;
57                 }
58
59                 option = strtok_r(line, " \t", &saveptr);
60                 if (option == NULL) {
61                         continue;
62                 }
63
64                 if (strcmp(option, "nameserver") != 0) {
65                         continue;
66                 }
67
68                 ns = strtok_r(NULL, " \t", &saveptr);
69                 if (ns == NULL) {
70                         continue;
71                 }
72
73                 tmp = talloc_realloc(
74                         mem_ctx,
75                         nameservers,
76                         char *,
77                         num_nameservers+1);
78                 if (tmp == NULL) {
79                         ret = ENOMEM;
80                         break;
81                 }
82                 nameservers = tmp;
83
84                 nameservers[num_nameservers] = talloc_strdup(nameservers, ns);
85                 if (nameservers[num_nameservers] == NULL) {
86                         ret = ENOMEM;
87                         break;
88                 }
89                 num_nameservers += 1;
90         }
91
92         SAFE_FREE(line);
93
94         if (ret == 0) {
95                 *pnameservers = nameservers;
96                 *pnum_nameservers = num_nameservers;
97         } else {
98                 TALLOC_FREE(nameservers);
99         }
100
101         return ret;
102 }
103
104 int parse_resolvconf(
105         const char *resolvconf,
106         TALLOC_CTX *mem_ctx,
107         char ***pnameservers,
108         size_t *pnum_nameservers)
109 {
110         FILE *fp;
111         int ret;
112
113         fp = fopen(resolvconf ? resolvconf : "/etc/resolv.conf", "r");
114         if (fp == NULL) {
115                 return errno;
116         }
117
118         ret = parse_resolvconf_fp(fp, mem_ctx, pnameservers, pnum_nameservers);
119
120         fclose(fp);
121
122         return ret;
123 }