2 * wait_for_sysfs.c - small program to delay the execution
3 * of /etc/hotplug.d/ programs, until sysfs
4 * is populated by the kernel. Depending on
5 * the type of device, we wait for all expected
6 * directories and then just exit.
8 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation version 2 of the License.
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 675 Mass Ave, Cambridge, MA 02139, USA.
35 #include "libsysfs/sysfs/libsysfs.h"
38 unsigned char logname[LOGNAME_SIZE];
39 void log_message(int level, const char *format, ...)
43 va_start(args, format);
44 vsyslog(level, format, args);
49 #define WAIT_MAX_SECONDS 5
50 #define WAIT_LOOP_PER_SECOND 20
52 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
54 static struct class_file {
58 { .subsystem = "net", .file = "ifindex" },
59 { .subsystem = "usb_host", .file = NULL },
60 { .subsystem = "pcmcia_socket", .file = NULL },
63 struct class_file *classfile;
64 const char *file = "dev";
67 /* look if we want to look for another file instead of "dev" */
68 for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
69 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
70 if (classfile->file == NULL) {
71 dbg("class '%s' has no file to wait for", class_dev->classname);
74 file = classfile->file;
78 dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
80 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
82 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
83 dbg("class '%s' specific file '%s' found", class_dev->classname, file);
88 dbg("error: getting bus '%s' specific file '%s'", class_dev->classname, file);
92 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
96 static char *devices_without_link[] = {
124 for (device = devices_without_link; *device != NULL; device++) {
125 int len = strlen(*device);
127 /* look if name matches */
128 if (strncmp(class_dev->name, *device, len) != 0)
132 if (strlen(class_dev->name) == len)
135 /* instance numbers are matching too */
136 if (isdigit(class_dev->name[len]))
143 static int wait_for_bus_device(struct sysfs_device *device_dev)
145 static struct bus_file {
149 { .bus = "scsi", .file = "vendor" },
150 { .bus = "usb", .file = "idVendor" },
151 { .bus = "usb", .file = "iInterface" },
152 { .bus = "usb-serial", .file = "detach_state" },
153 { .bus = "ide", .file = "detach_state" },
154 { .bus = "pci", .file = "vendor" },
157 struct bus_file *busfile;
160 /* wait for the /bus-device link to the /device-device */
161 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
163 if (sysfs_get_device_bus(device_dev) == 0)
166 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
169 dbg("error: getting /bus-device link");
172 dbg("/bus-device link found for bus '%s'", device_dev->bus);
174 /* wait for a bus specific file to show up */
175 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
177 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
178 if (strcmp(device_dev->bus, busfile->bus) == 0) {
179 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
180 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
181 dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
184 if (busfile->bus == NULL) {
185 info("error: unknown bus, update the build-in list '%s'", device_dev->bus);
192 dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
196 int main(int argc, char *argv[], char *envp[])
198 const char *devpath = "";
200 const char *subsystem;
201 char sysfs_path[SYSFS_PATH_MAX];
202 char filename[SYSFS_PATH_MAX];
203 struct sysfs_class_device *class_dev;
204 struct sysfs_class_device *class_dev_parent;
205 struct sysfs_device *device_dev = NULL;
210 dbg("error: subsystem");
215 devpath = getenv ("DEVPATH");
217 dbg("error: no DEVPATH");
221 action = getenv ("ACTION");
223 dbg("error: no ACTION");
227 if (strcmp(action, "add") != 0)
230 if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
231 dbg("error: no sysfs path");
235 if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
236 /* open the class device we are called for */
237 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
238 filename[SYSFS_PATH_MAX-1] = '\0';
240 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
242 class_dev = sysfs_open_class_device_path(filename);
246 if (class_dev == NULL) {
247 dbg("error: getting class_device");
251 dbg("class_device opened '%s'", filename);
253 wait_for_class_device_attributes(class_dev);
255 if (class_device_expect_no_device_link(class_dev)) {
256 dbg("no device symlink expected");
257 sysfs_close_class_device(class_dev);
261 /* the symlink may be on the parent device */
262 class_dev_parent = sysfs_get_classdev_parent(class_dev);
263 if (class_dev_parent)
264 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
266 /* wait for the symlink to the /device-device */
267 dbg("waiting for symlink to /device-device");
268 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
270 if (class_dev_parent)
271 device_dev = sysfs_get_classdev_device(class_dev_parent);
273 device_dev = sysfs_get_classdev_device(class_dev);
278 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
280 if (device_dev == NULL) {
281 dbg("error: getting /device-device");
282 sysfs_close_class_device(class_dev);
286 dbg("device symlink found pointing to '%s'", device_dev->path);
288 /* wait for the bus value */
289 if (wait_for_bus_device(device_dev) != 0)
291 sysfs_close_class_device(class_dev);
296 } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
297 /* open the path we are called for */
298 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
299 filename[SYSFS_PATH_MAX-1] = '\0';
301 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
303 device_dev = sysfs_open_device_path(filename);
307 if (device_dev == NULL) {
308 dbg("error: getting /device-device");
312 dbg("device_device opened '%s'", filename);
314 /* wait for the bus value */
315 if (wait_for_bus_device(device_dev) != 0)
318 sysfs_close_device(device_dev);
324 dbg("unhandled sysfs path, no need to wait");
329 info("result: waiting for sysfs successful '%s'", devpath);
331 info("result: waiting for sysfs failed '%s'", devpath);