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bd284db1 SJR |
1 | /* |
2 | * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org> | |
3 | * Copyright (C) 2009 Canonical Ltd. | |
4 | * | |
5 | * This program is free software: you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation, either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
17 | */ | |
18 | ||
19 | #include <sys/types.h> | |
20 | #include <errno.h> | |
21 | #include <fcntl.h> | |
22 | #include <stdio.h> | |
23 | #include <dirent.h> | |
24 | #include <stddef.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <unistd.h> | |
28 | #ifdef HAVE_INOTIFY | |
29 | #include <sys/inotify.h> | |
30 | #endif | |
31 | ||
32 | #include "udev.h" | |
33 | ||
34 | int inotify_fd = -1; | |
35 | ||
36 | /* inotify descriptor, will be shared with rules directory; | |
37 | * set to cloexec since we need our children to be able to add | |
38 | * watches for us | |
39 | */ | |
40 | void udev_watch_init(struct udev *udev) | |
41 | { | |
42 | inotify_fd = inotify_init(); | |
43 | if (inotify_fd >= 0) { | |
44 | int flags; | |
45 | ||
46 | flags = fcntl(inotify_fd, F_GETFD); | |
47 | if (flags < 0) | |
48 | flags = FD_CLOEXEC; | |
49 | else | |
50 | flags |= FD_CLOEXEC; | |
51 | fcntl(inotify_fd, F_SETFD, flags); | |
52 | } else if (errno == ENOSYS) | |
53 | info(udev, "unable to use inotify, udevd will not monitor rule files changes\n"); | |
54 | else | |
55 | err(udev, "inotify_init failed: %m\n"); | |
56 | } | |
57 | ||
58 | /* move any old watches directory out of the way, and then restore | |
59 | * the watches | |
60 | */ | |
61 | void udev_watch_restore(struct udev *udev) | |
62 | { | |
63 | char filename[UTIL_PATH_SIZE], oldname[UTIL_PATH_SIZE]; | |
64 | ||
65 | if (inotify_fd < 0) | |
66 | return; | |
67 | ||
68 | util_strlcpy(oldname, udev_get_dev_path(udev), sizeof(oldname)); | |
69 | util_strlcat(oldname, "/.udev/watch.old", sizeof(oldname)); | |
70 | ||
71 | util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename)); | |
72 | util_strlcat(filename, "/.udev/watch", sizeof(filename)); | |
73 | ||
74 | if (rename(filename, oldname) == 0) { | |
75 | DIR *dir; | |
76 | struct dirent *ent; | |
77 | ||
78 | dir = opendir(oldname); | |
79 | if (dir == NULL) { | |
80 | err(udev, "unable to open old watches dir '%s', old watches will not be restored: %m", oldname); | |
81 | return; | |
82 | } | |
83 | ||
84 | while ((ent = readdir(dir)) != NULL) { | |
85 | char path[UTIL_PATH_SIZE]; | |
86 | char buf[UTIL_PATH_SIZE]; | |
87 | ssize_t len; | |
88 | struct udev_device *dev; | |
89 | ||
90 | if (ent->d_name[0] < '0' || ent->d_name[0] > '9') | |
91 | continue; | |
92 | ||
93 | util_strlcpy(path, oldname, sizeof(path)); | |
94 | util_strlcat(path, "/", sizeof(path)); | |
95 | util_strlcat(path, ent->d_name, sizeof(path)); | |
96 | ||
97 | len = readlink(path, buf, sizeof(buf)); | |
98 | if (len <= 0) { | |
99 | unlink(path); | |
100 | continue; | |
101 | } | |
102 | ||
103 | buf[len] = '\0'; | |
104 | dbg(udev, "old watch to '%s' found\n", buf); | |
bd284db1 SJR |
105 | dev = udev_device_new_from_syspath(udev, buf); |
106 | if (dev == NULL) { | |
107 | unlink(path); | |
108 | continue; | |
109 | } | |
110 | ||
bd284db1 SJR |
111 | info(udev, "restoring old watch on '%s'\n", udev_device_get_devnode(dev)); |
112 | udev_watch_begin(udev, dev); | |
113 | ||
114 | udev_device_unref(dev); | |
bd284db1 SJR |
115 | unlink(path); |
116 | } | |
117 | ||
118 | closedir(dir); | |
119 | rmdir(oldname); | |
120 | ||
121 | } else if (errno != ENOENT) { | |
122 | err(udev, "unable to move watches dir '%s', old watches will not be restored: %m", filename); | |
123 | } | |
124 | } | |
125 | ||
126 | static const char *udev_watch_filename(struct udev *udev, int wd) | |
127 | { | |
128 | static char filename[UTIL_PATH_SIZE]; | |
129 | char str[32]; | |
130 | ||
131 | sprintf(str, "%d", wd); | |
132 | util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename)); | |
133 | util_strlcat(filename, "/.udev/watch/", sizeof(filename)); | |
134 | util_strlcat(filename, str, sizeof(filename)); | |
135 | ||
136 | return filename; | |
137 | } | |
138 | ||
139 | void udev_watch_begin(struct udev *udev, struct udev_device *dev) | |
140 | { | |
141 | const char *filename; | |
142 | int wd; | |
143 | ||
144 | if (inotify_fd < 0) | |
145 | return; | |
146 | ||
4aca304e | 147 | wd = inotify_add_watch(inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE); |
bd284db1 SJR |
148 | if (wd < 0) { |
149 | err(udev, "inotify_add_watch(%d, %s, %o) failed: %m\n", | |
150 | inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE); | |
151 | } | |
152 | ||
153 | filename = udev_watch_filename(udev, wd); | |
154 | util_create_path(udev, filename); | |
155 | unlink(filename); | |
156 | symlink(udev_device_get_syspath(dev), filename); | |
157 | } | |
158 | ||
159 | void udev_watch_clear(struct udev *udev, struct udev_device *dev) | |
160 | { | |
161 | static char filename[UTIL_PATH_SIZE]; | |
162 | DIR *dir; | |
163 | struct dirent *ent; | |
164 | ||
165 | util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename)); | |
166 | util_strlcat(filename, "/.udev/watch", sizeof(filename)); | |
167 | ||
168 | dir = opendir(filename); | |
169 | if (dir == NULL) | |
170 | return; | |
171 | ||
172 | while ((ent = readdir(dir)) != NULL) { | |
173 | char path[UTIL_PATH_SIZE]; | |
174 | char buf[UTIL_PATH_SIZE]; | |
175 | ssize_t len; | |
176 | ||
177 | if (ent->d_name[0] < '0' || ent->d_name[0] > '9') | |
178 | continue; | |
179 | ||
180 | util_strlcpy(path, filename, sizeof(path)); | |
181 | util_strlcat(path, "/", sizeof(path)); | |
182 | util_strlcat(path, ent->d_name, sizeof(path)); | |
183 | ||
184 | len = readlink(path, buf, sizeof(buf)); | |
185 | if (len <= 0) | |
186 | continue; | |
187 | ||
188 | buf[len] = '\0'; | |
189 | if (strcmp(buf, udev_device_get_syspath(dev))) | |
190 | continue; | |
191 | ||
192 | /* this is the watch we're looking for */ | |
193 | info(udev, "clearing existing watch on '%s'\n", udev_device_get_devnode(dev)); | |
194 | udev_watch_end(udev, atoi(ent->d_name)); | |
195 | } | |
196 | ||
197 | closedir(dir); | |
198 | } | |
199 | ||
200 | void udev_watch_end(struct udev *udev, int wd) | |
201 | { | |
202 | const char *filename; | |
203 | ||
204 | if (inotify_fd < 0 || wd < 0) | |
205 | return; | |
206 | ||
207 | inotify_rm_watch(inotify_fd, wd); | |
208 | ||
209 | filename = udev_watch_filename(udev, wd); | |
210 | unlink(filename); | |
211 | } | |
212 | ||
213 | const char *udev_watch_lookup(struct udev *udev, int wd) | |
214 | { | |
215 | const char *filename; | |
216 | static char buf[UTIL_PATH_SIZE]; | |
217 | ssize_t len; | |
218 | ||
219 | if (inotify_fd < 0 || wd < 0) | |
220 | return NULL; | |
221 | ||
222 | filename = udev_watch_filename(udev, wd); | |
223 | len = readlink(filename, buf, sizeof(buf)); | |
224 | if (len > 0) { | |
225 | buf[len] = '\0'; | |
226 | ||
227 | return buf; | |
228 | } | |
229 | ||
230 | return NULL; | |
231 | } |