fd293a4645647ca3550d6966d18e463613f7ca48
[project/procd.git] / udevtrigger.c
1 /*
2  * Copyright (C) 2004-2006 Kay Sievers <kay@vrfy.org>
3  * Copyright (C) 2006 Hannes Reinecke <hare@suse.de>
4  *
5  *      This program is free software; you can redistribute it and/or modify it
6  *      under the terms of the GNU General Public License as published by the
7  *      Free Software Foundation version 2 of the License.
8  *
9  *      This program is distributed in the hope that it will be useful, but
10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  *      General Public License for more details.
13  *
14  *      You should have received a copy of the GNU General Public License along
15  *      with this program; if not, write to the Free Software Foundation, Inc.,
16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
17  *
18  */
19
20 #include <stdlib.h>
21 #include <stddef.h>
22 #include <stdarg.h>
23 #include <stdio.h>
24 #include <stdbool.h>
25 #include <unistd.h>
26 #include <getopt.h>
27 #include <errno.h>
28 #include <dirent.h>
29 #include <fcntl.h>
30 #include <syslog.h>
31 #include <sys/stat.h>
32 #include <sys/types.h>
33 #include <string.h>
34
35 #define PATH_SIZE 512
36
37 #ifndef strlcpy
38 #define strlcpy(d,s,l) (strncpy(d,s,l), (d)[(l)-1] = '\0')
39 #endif
40
41 #ifndef strlcat
42 #define strlcat(d,s,l) strncat(d,s,(l)-strlen(d)-1)
43 #endif
44
45 static int verbose;
46 static int dry_run;
47
48 static void log_message(int priority, const char *format, ...)
49 {
50         va_list args;
51
52         va_start(args, format);
53         vsyslog(priority, format, args);
54         va_end(args);
55 }
56
57 #undef err
58 #define err(format, arg...)                         \
59     do {                                    \
60         log_message(LOG_ERR ,"%s: " format ,__FUNCTION__ ,## arg);  \
61     } while (0)
62
63 #undef info
64 #define info(format, arg...)                            \
65     do {                                    \
66         log_message(LOG_INFO ,"%s: " format ,__FUNCTION__ ,## arg); \
67     } while (0)
68
69 #ifdef DEBUG
70 #undef dbg
71 #define dbg(format, arg...)                         \
72     do {                                    \
73         log_message(LOG_DEBUG ,"%s: " format ,__FUNCTION__ ,## arg);    \
74     } while (0)
75 #else
76 #define dbg(...) do {} while(0)
77 #endif
78
79
80 static void trigger_uevent(const char *devpath)
81 {
82         char filename[PATH_SIZE];
83         int fd;
84
85         strlcpy(filename, "/sys", sizeof(filename));
86         strlcat(filename, devpath, sizeof(filename));
87         strlcat(filename, "/uevent", sizeof(filename));
88
89         if (verbose)
90                 printf("%s\n", devpath);
91
92         if (dry_run)
93                 return;
94
95         fd = open(filename, O_WRONLY);
96         if (fd < 0) {
97                 dbg("error on opening %s: %s\n", filename, strerror(errno));
98                 return;
99         }
100
101         if (write(fd, "add", 3) < 0)
102                 info("error on triggering %s: %s\n", filename, strerror(errno));
103
104         close(fd);
105 }
106
107 static int sysfs_resolve_link(char *devpath, size_t size)
108 {
109         char link_path[PATH_SIZE];
110         char link_target[PATH_SIZE];
111         int len;
112         int i;
113         int back;
114
115         strlcpy(link_path, "/sys", sizeof(link_path));
116         strlcat(link_path, devpath, sizeof(link_path));
117         len = readlink(link_path, link_target, sizeof(link_target));
118         if (len <= 0)
119                 return -1;
120         link_target[len] = '\0';
121         dbg("path link '%s' points to '%s'", devpath, link_target);
122
123         for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
124                 ;
125         dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back);
126         for (i = 0; i <= back; i++) {
127                 char *pos = strrchr(devpath, '/');
128
129                 if (pos == NULL)
130                         return -1;
131                 pos[0] = '\0';
132         }
133         dbg("after moving back '%s'", devpath);
134         strlcat(devpath, "/", size);
135         strlcat(devpath, &link_target[back * 3], size);
136         return 0;
137 }
138
139 static bool device_has_attribute(const char *path, const char *attr,
140                                  mode_t mode)
141 {
142         char filename[PATH_SIZE];
143         struct stat statbuf;
144
145         strlcpy(filename, path, sizeof(filename));
146         strlcat(filename, attr, sizeof(filename));
147
148         if (stat(filename, &statbuf) < 0)
149                 return false;
150
151         if (!(statbuf.st_mode & mode))
152                 return false;
153
154         return true;
155 }
156
157 static int device_list_insert(const char *path)
158 {
159         char devpath[PATH_SIZE];
160         struct stat statbuf;
161
162         dbg("add '%s'" , path);
163
164         /* we only have a device, if we have a dev and an uevent file */
165         if (!device_has_attribute(path, "/dev", S_IRUSR) ||
166             !device_has_attribute(path, "/uevent", S_IWUSR))
167                 return -1;
168
169         strlcpy(devpath, &path[4], sizeof(devpath));
170
171         /* resolve possible link to real target */
172         if (lstat(path, &statbuf) < 0)
173                 return -1;
174         if (S_ISLNK(statbuf.st_mode))
175                 if (sysfs_resolve_link(devpath, sizeof(devpath)) != 0)
176                         return -1;
177
178         trigger_uevent(devpath);
179         return 0;
180 }
181
182 static void scan_subdir(const char *dirname)
183 {
184         DIR *dir2;
185         struct dirent *dent2;
186
187         dir2 = opendir(dirname);
188         if (dir2 != NULL) {
189                 for (dent2 = readdir(dir2); dent2 != NULL; dent2 = readdir(dir2)) {
190                         char dirname2[PATH_SIZE];
191
192                         if (dent2->d_name[0] == '.')
193                                 continue;
194
195                         strlcpy(dirname2, dirname, sizeof(dirname2));
196                         strlcat(dirname2, "/", sizeof(dirname2));
197                         strlcat(dirname2, dent2->d_name, sizeof(dirname2));
198                         device_list_insert(dirname2);
199                 }
200                 closedir(dir2);
201         }
202 }
203
204 static void scan_subsystem(const char *subsys)
205 {
206         char base[PATH_SIZE];
207         DIR *dir;
208         struct dirent *dent;
209
210         strlcpy(base, "/sys/", sizeof(base));
211         strlcat(base, subsys, sizeof(base));
212
213         dir = opendir(base);
214         if (dir != NULL) {
215                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
216                         char dirname[PATH_SIZE];
217
218                         if (dent->d_name[0] == '.')
219                                 continue;
220
221                         strlcpy(dirname, base, sizeof(dirname));
222                         strlcat(dirname, "/", sizeof(dirname));
223                         strlcat(dirname, dent->d_name, sizeof(dirname));
224                         strlcat(dirname, "/devices", sizeof(dirname));
225
226                         /* look for devices */
227                         scan_subdir(dirname);
228                 }
229                 closedir(dir);
230         }
231 }
232
233 static void scan_block(void)
234 {
235         char base[PATH_SIZE];
236         DIR *dir;
237         struct dirent *dent;
238
239         strlcpy(base, "/sys/block", sizeof(base));
240
241         dir = opendir(base);
242         if (dir != NULL) {
243                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
244                         char dirname[PATH_SIZE];
245
246                         if (dent->d_name[0] == '.')
247                                 continue;
248
249                         strlcpy(dirname, base, sizeof(dirname));
250                         strlcat(dirname, "/", sizeof(dirname));
251                         strlcat(dirname, dent->d_name, sizeof(dirname));
252                         if (device_list_insert(dirname) != 0)
253                                 continue;
254
255                         /* look for partitions */
256                         scan_subdir(dirname);
257                 }
258                 closedir(dir);
259         }
260 }
261
262 static void scan_class(void)
263 {
264         char base[PATH_SIZE];
265         DIR *dir;
266         struct dirent *dent;
267
268         strlcpy(base, "/sys/class", sizeof(base));
269
270         dir = opendir(base);
271         if (dir != NULL) {
272                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
273                         char dirname[PATH_SIZE];
274
275                         if (dent->d_name[0] == '.')
276                                 continue;
277
278                         strlcpy(dirname, base, sizeof(dirname));
279                         strlcat(dirname, "/", sizeof(dirname));
280                         strlcat(dirname, dent->d_name, sizeof(dirname));
281
282                         scan_subdir(dirname);
283                 }
284                 closedir(dir);
285         }
286 }
287
288 int main(int argc, char *argv[], char *envp[])
289 {
290         char base[PATH_SIZE];
291         struct stat statbuf;
292         int option;
293
294         openlog("udevtrigger", LOG_PID | LOG_CONS, LOG_DAEMON);
295
296         while (1) {
297                 option = getopt(argc, argv, "vnh");
298                 if (option == -1)
299                         break;
300
301                 switch (option) {
302                 case 'v':
303                         verbose = 1;
304                         break;
305                 case 'n':
306                         dry_run = 1;
307                         break;
308                 case 'h':
309                         printf("Usage: udevtrigger OPTIONS\n"
310                                "  -v                     print the list of devices while running\n"
311                                "  -n                     do not actually trigger the events\n"
312                                "  -h                     print this text\n"
313                                "\n");
314                         goto exit;
315                 default:
316                         goto exit;
317                 }
318         }
319
320
321         /* if we have /sys/subsystem, forget all the old stuff */
322         scan_subsystem("bus");
323         scan_class();
324
325         /* scan "block" if it isn't a "class" */
326         strlcpy(base, "/sys/class/block", sizeof(base));
327         if (stat(base, &statbuf) != 0)
328                 scan_block();
329
330 exit:
331
332         closelog();
333         return 0;
334 }