2 * wait_for_sysfs.c - small program to delay the execution
3 * of /etc/hotplug.d/ programs, until sysfs
4 * is fully 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 /* wait for specific file to show up, normally the "dev"-file */
53 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
55 static struct class_file {
59 { .subsystem = "net", .file = "ifindex" },
60 { .subsystem = "scsi_host", .file = "unique_id" },
61 { .subsystem = "scsi_device", .file = NULL },
62 { .subsystem = "pcmcia_socket", .file = "card_type" },
63 { .subsystem = "usb_host", .file = NULL },
66 struct class_file *classfile;
67 const char *file = "dev";
70 /* look if we want to look for another file instead of "dev" */
71 for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
72 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
73 if (classfile->file == NULL) {
74 dbg("class '%s' has no file to wait for", class_dev->classname);
77 file = classfile->file;
81 dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
83 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
85 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
86 dbg("class '%s' specific file '%s' found", class_dev->classname, file);
90 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
93 dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
97 /* skip waiting for physical device */
98 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
100 static char *devices_without_link[] = {
129 for (device = devices_without_link; *device != NULL; device++) {
130 int len = strlen(*device);
132 /* look if name matches */
133 if (strncmp(class_dev->name, *device, len) != 0)
137 if (strlen(class_dev->name) == len)
140 /* instance numbers are matching too */
141 if (isdigit(class_dev->name[len]))
148 /* skip waiting for the bus */
149 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
151 static char *devices_without_bus[] = {
157 for (device = devices_without_bus; *device != NULL; device++) {
158 int len = strlen(*device);
160 if (strncmp(class_dev->classname, *device, len) == 0)
167 /* wait for the bus and for a bus specific file to show up */
168 static int wait_for_bus_device(struct sysfs_device *device_dev)
170 static struct bus_file {
174 { .bus = "scsi", .file = "vendor" },
175 { .bus = "usb", .file = "idVendor" },
176 { .bus = "usb", .file = "iInterface" },
177 { .bus = "usb", .file = "bNumEndpoints" },
178 { .bus = "usb-serial", .file = "detach_state" },
179 { .bus = "ide", .file = "detach_state" },
180 { .bus = "pci", .file = "vendor" },
181 { .bus = "platform", .file = "detach_state" },
184 struct bus_file *busfile;
187 /* wait for the /bus-device link to the /device-device */
188 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
190 if (sysfs_get_device_bus(device_dev) == 0)
193 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
196 dbg("error: getting /bus-device link");
199 dbg("/bus-device link found for bus '%s'", device_dev->bus);
201 /* wait for a bus specific file to show up */
202 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
206 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
207 if (strcmp(device_dev->bus, busfile->bus) == 0) {
209 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
210 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
211 dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
217 info("error: unknown bus, please report to "
218 "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
221 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
224 dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
228 int main(int argc, char *argv[], char *envp[])
230 const char *devpath = "";
232 const char *subsystem;
233 char sysfs_path[SYSFS_PATH_MAX];
234 char filename[SYSFS_PATH_MAX];
235 struct sysfs_class_device *class_dev;
236 struct sysfs_class_device *class_dev_parent;
237 struct sysfs_device *device_dev = NULL;
241 init_logging("wait_for_sysfs");
244 dbg("error: subsystem");
249 devpath = getenv ("DEVPATH");
251 dbg("error: no DEVPATH");
255 action = getenv ("ACTION");
257 dbg("error: no ACTION");
261 /* we only wait on an add event */
262 if (strcmp(action, "add") != 0)
265 if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
266 dbg("error: no sysfs path");
270 if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
271 /* open the class device we are called for */
272 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
273 filename[SYSFS_PATH_MAX-1] = '\0';
275 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
277 class_dev = sysfs_open_class_device_path(filename);
281 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
283 if (class_dev == NULL) {
284 dbg("error: getting class_device");
288 dbg("class_device opened '%s'", filename);
290 if (wait_for_class_device_attributes(class_dev) != 0) {
295 /* skip devices without /device-link */
296 if (class_device_expect_no_device_link(class_dev)) {
297 dbg("no device symlink expected for '%s', ", class_dev->name);
301 /* the symlink may be on the parent device */
302 class_dev_parent = sysfs_get_classdev_parent(class_dev);
303 if (class_dev_parent)
304 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
306 /* wait for the symlink to the /device-device */
307 dbg("waiting for symlink to /device-device");
308 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
310 if (class_dev_parent)
311 device_dev = sysfs_get_classdev_device(class_dev_parent);
313 device_dev = sysfs_get_classdev_device(class_dev);
318 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
320 if (device_dev == NULL) {
321 dbg("error: getting /device-device");
325 dbg("device symlink found pointing to '%s'", device_dev->path);
327 /* wait for the bus value */
328 if (class_device_expect_no_bus(class_dev)) {
329 dbg("no bus device expected for '%s', ", class_dev->classname);
331 if (wait_for_bus_device(device_dev) != 0)
336 sysfs_close_class_device(class_dev);
338 } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
339 /* open the path we are called for */
340 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
341 filename[SYSFS_PATH_MAX-1] = '\0';
343 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
345 device_dev = sysfs_open_device_path(filename);
349 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
351 if (device_dev == NULL) {
352 dbg("error: getting /device-device");
356 dbg("device_device opened '%s'", filename);
358 /* wait for the bus value */
359 if (wait_for_bus_device(device_dev) != 0)
362 sysfs_close_device(device_dev);
365 dbg("unhandled sysfs path, no need to wait");
370 dbg("result: waiting for sysfs successful '%s'", devpath);
372 info("error: wait_for_sysfs needs an update to handle the device '%s' "
373 "properly, please report to <linux-hotplug-devel@lists.sourceforge.net>",