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aff33962 | 1 | /* dnsmasq is Copyright (c) 2000-2015 Simon Kelley |
193de4ab SK |
2 | |
3 | This program is free software; you can redistribute it and/or modify | |
4 | it under the terms of the GNU General Public License as published by | |
5 | the Free Software Foundation; version 2 dated June, 1991, or | |
6 | (at your option) version 3 dated 29 June, 2007. | |
7 | ||
8 | This program is distributed in the hope that it will be useful, | |
9 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | GNU General Public License for more details. | |
12 | ||
13 | You should have received a copy of the GNU General Public License | |
14 | along with this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | ||
17 | #include "dnsmasq.h" | |
0491805d | 18 | #ifdef HAVE_INOTIFY |
193de4ab | 19 | |
d310ab7e MA |
20 | #include <sys/inotify.h> |
21 | ||
193de4ab SK |
22 | /* the strategy is to set a inotify on the directories containing |
23 | resolv files, for any files in the directory which are close-write | |
24 | or moved into the directory. | |
25 | ||
26 | When either of those happen, we look to see if the file involved | |
27 | is actually a resolv-file, and if so, call poll-resolv with | |
28 | the "force" argument, to ensure it's read. | |
29 | ||
30 | This adds one new error condition: the directories containing | |
31 | all specified resolv-files must exist at start-up, even if the actual | |
32 | files don't. | |
33 | */ | |
34 | ||
35 | static char *inotify_buffer; | |
36 | #define INOTIFY_SZ (sizeof(struct inotify_event) + NAME_MAX + 1) | |
37 | ||
38 | void inotify_dnsmasq_init() | |
39 | { | |
40 | struct resolvc *res; | |
41 | ||
42 | inotify_buffer = safe_malloc(INOTIFY_SZ); | |
857973e6 SK |
43 | daemon->inotifyfd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC); |
44 | ||
193de4ab SK |
45 | if (daemon->inotifyfd == -1) |
46 | die(_("failed to create inotify: %s"), NULL, EC_MISC); | |
857973e6 | 47 | |
193de4ab SK |
48 | for (res = daemon->resolv_files; res; res = res->next) |
49 | { | |
857973e6 | 50 | char *d = NULL, *path; |
193de4ab | 51 | |
857973e6 SK |
52 | if (!(path = realpath(res->name, NULL))) |
53 | { | |
54 | /* realpath will fail if the file doesn't exist, but | |
55 | dnsmasq copes with missing files, so fall back | |
56 | and assume that symlinks are not in use in that case. */ | |
57 | if (errno == ENOENT) | |
58 | path = res->name; | |
59 | else | |
60 | die(_("cannot cannonicalise resolv-file %s: %s"), res->name, EC_MISC); | |
61 | } | |
193de4ab | 62 | |
857973e6 SK |
63 | if ((d = strrchr(path, '/'))) |
64 | { | |
65 | *d = 0; /* make path just directory */ | |
66 | res->wd = inotify_add_watch(daemon->inotifyfd, path, IN_CLOSE_WRITE | IN_MOVED_TO); | |
5f4dc5c6 | 67 | |
857973e6 SK |
68 | res->file = d+1; /* pointer to filename */ |
69 | *d = '/'; | |
70 | ||
71 | if (res->wd == -1 && errno == ENOENT) | |
72 | die(_("directory %s for resolv-file is missing, cannot poll"), res->name, EC_MISC); | |
73 | ||
74 | if (res->wd == -1) | |
75 | die(_("failed to create inotify for %s: %s"), res->name, EC_MISC); | |
76 | } | |
193de4ab SK |
77 | } |
78 | } | |
79 | ||
70d1873d SK |
80 | |
81 | /* initialisation for dynamic-dir. Set inotify watch for each directory, and read pre-existing files */ | |
82 | void set_dynamic_inotify(int flag, int total_size, struct crec **rhash, int revhashsz) | |
193de4ab | 83 | { |
70d1873d | 84 | struct hostsfile *ah; |
193de4ab | 85 | |
70d1873d | 86 | for (ah = daemon->dynamic_dirs; ah; ah = ah->next) |
193de4ab | 87 | { |
70d1873d SK |
88 | DIR *dir_stream = NULL; |
89 | struct dirent *ent; | |
90 | struct stat buf; | |
91 | ||
92 | if (!(ah->flags & flag)) | |
93 | continue; | |
94 | ||
95 | if (stat(ah->fname, &buf) == -1 || !(S_ISDIR(buf.st_mode))) | |
193de4ab | 96 | { |
70d1873d SK |
97 | my_syslog(LOG_ERR, _("bad dynamic directory %s: %s"), |
98 | ah->fname, strerror(errno)); | |
99 | continue; | |
193de4ab | 100 | } |
70d1873d | 101 | |
5f4dc5c6 SK |
102 | if (!(ah->flags & AH_WD_DONE)) |
103 | { | |
104 | ah->wd = inotify_add_watch(daemon->inotifyfd, ah->fname, IN_CLOSE_WRITE | IN_MOVED_TO); | |
105 | ah->flags |= AH_WD_DONE; | |
106 | } | |
107 | /* Read contents of dir _after_ calling add_watch, in the ho[e of avoiding | |
108 | a race which misses files being added as we start */ | |
109 | if (ah->wd == -1 || !(dir_stream = opendir(ah->fname))) | |
110 | { | |
70d1873d SK |
111 | my_syslog(LOG_ERR, _("failed to create inotify for %s: %s"), |
112 | ah->fname, strerror(errno)); | |
5f4dc5c6 SK |
113 | continue; |
114 | } | |
115 | ||
116 | while ((ent = readdir(dir_stream))) | |
117 | { | |
118 | size_t lendir = strlen(ah->fname); | |
119 | size_t lenfile = strlen(ent->d_name); | |
120 | char *path; | |
121 | ||
122 | /* ignore emacs backups and dotfiles */ | |
123 | if (lenfile == 0 || | |
124 | ent->d_name[lenfile - 1] == '~' || | |
125 | (ent->d_name[0] == '#' && ent->d_name[lenfile - 1] == '#') || | |
126 | ent->d_name[0] == '.') | |
127 | continue; | |
128 | ||
129 | if ((path = whine_malloc(lendir + lenfile + 2))) | |
130 | { | |
131 | strcpy(path, ah->fname); | |
132 | strcat(path, "/"); | |
133 | strcat(path, ent->d_name); | |
134 | ||
135 | /* ignore non-regular files */ | |
136 | if (stat(path, &buf) != -1 && S_ISREG(buf.st_mode)) | |
70d1873d SK |
137 | { |
138 | if (ah->flags & AH_HOSTS) | |
139 | total_size = read_hostsfile(path, ah->index, total_size, rhash, revhashsz); | |
140 | #ifdef HAVE_DHCP | |
141 | else if (ah->flags & (AH_DHCP_HST | AH_DHCP_OPT)) | |
142 | option_read_dynfile(path, ah->flags); | |
143 | #endif | |
144 | } | |
145 | ||
5f4dc5c6 SK |
146 | free(path); |
147 | } | |
148 | } | |
149 | } | |
150 | } | |
151 | ||
70d1873d | 152 | int inotify_check(time_t now) |
5f4dc5c6 | 153 | { |
70d1873d | 154 | int hit = 0; |
5f4dc5c6 SK |
155 | struct hostsfile *ah; |
156 | ||
70d1873d SK |
157 | while (1) |
158 | { | |
159 | int rc; | |
160 | char *p; | |
161 | struct resolvc *res; | |
162 | struct inotify_event *in; | |
163 | ||
164 | while ((rc = read(daemon->inotifyfd, inotify_buffer, INOTIFY_SZ)) == -1 && errno == EINTR); | |
165 | ||
166 | if (rc <= 0) | |
167 | break; | |
168 | ||
169 | for (p = inotify_buffer; rc - (p - inotify_buffer) >= (int)sizeof(struct inotify_event); p += sizeof(struct inotify_event) + in->len) | |
170 | { | |
171 | in = (struct inotify_event*)p; | |
172 | ||
173 | for (res = daemon->resolv_files; res; res = res->next) | |
174 | if (res->wd == in->wd && in->len != 0 && strcmp(res->file, in->name) == 0) | |
175 | hit = 1; | |
176 | ||
177 | /* ignore emacs backups and dotfiles */ | |
178 | if (in->len == 0 || | |
179 | in->name[in->len - 1] == '~' || | |
180 | (in->name[0] == '#' && in->name[in->len - 1] == '#') || | |
181 | in->name[0] == '.') | |
182 | continue; | |
183 | ||
184 | for (ah = daemon->dynamic_dirs; ah; ah = ah->next) | |
185 | if (ah->wd == in->wd) | |
5f4dc5c6 | 186 | { |
70d1873d SK |
187 | size_t lendir = strlen(ah->fname); |
188 | char *path; | |
189 | ||
190 | if ((path = whine_malloc(lendir + in->len + 2))) | |
191 | { | |
192 | strcpy(path, ah->fname); | |
193 | strcat(path, "/"); | |
194 | strcat(path, in->name); | |
195 | ||
196 | if (ah->flags & AH_HOSTS) | |
2941d3ac SK |
197 | { |
198 | read_hostsfile(path, ah->index, 0, NULL, 0); | |
199 | #ifdef HAVE_DHCP | |
200 | if (daemon->dhcp || daemon->doing_dhcp6) | |
201 | { | |
202 | /* Propogate the consequences of loading a new dhcp-host */ | |
203 | dhcp_update_configs(daemon->dhcp_conf); | |
204 | lease_update_from_configs(); | |
205 | lease_update_file(now); | |
206 | lease_update_dns(1); | |
207 | } | |
208 | #endif | |
209 | } | |
70d1873d SK |
210 | #ifdef HAVE_DHCP |
211 | else if (ah->flags & AH_DHCP_HST) | |
212 | { | |
213 | if (option_read_dynfile(path, AH_DHCP_HST)) | |
214 | { | |
215 | /* Propogate the consequences of loading a new dhcp-host */ | |
216 | dhcp_update_configs(daemon->dhcp_conf); | |
217 | lease_update_from_configs(); | |
218 | lease_update_file(now); | |
219 | lease_update_dns(1); | |
220 | } | |
221 | } | |
222 | else if (ah->flags & AH_DHCP_OPT) | |
223 | option_read_dynfile(path, AH_DHCP_OPT); | |
224 | #endif | |
225 | ||
226 | free(path); | |
227 | } | |
5f4dc5c6 | 228 | } |
70d1873d SK |
229 | } |
230 | } | |
231 | return hit; | |
5f4dc5c6 SK |
232 | } |
233 | ||
0491805d | 234 | #endif /* INOTIFY */ |
193de4ab | 235 |