wait_for_sysfs.c

   1 /*
   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.
   7  *
   8  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   9  *
  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.
  13  *
  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.
  18  *
  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.
  22  *
  23  */
  24
  25 #include <stdio.h>
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <errno.h>
  32 #include <sys/stat.h>
  33
  34 #include "logging.h"
  35 #include "udev_version.h"
  36 #include "libsysfs/sysfs/libsysfs.h"
  37
  38 #ifdef LOG
  39 unsigned char logname[LOGNAME_SIZE];
  40 void log_message(int level, const char *format, ...)
  41 {
  42         va_list args;
  43
  44         va_start(args, format);
  45         vsyslog(level, format, args);
  46         va_end(args);
  47 }
  48 #endif
  49
  50 #define WAIT_MAX_SECONDS                5
  51 #define WAIT_LOOP_PER_SECOND            20
  52
  53 /* wait for specific file to show up, normally the "dev"-file */
  54 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
  55 {
  56         static struct class_file {
  57                 char *subsystem;
  58                 char *file;
  59         } class_files[] = {
  60                 { .subsystem = "net",           .file = "ifindex" },
  61                 { .subsystem = "scsi_host",     .file = "unique_id" },
  62                 { .subsystem = "scsi_device",   .file = NULL },
  63                 { .subsystem = "pcmcia_socket", .file = "card_type" },
  64                 { .subsystem = "usb_host",      .file = NULL },
  65                 { .subsystem = "bluetooth",     .file = "address" },
  66                 { .subsystem = "i2c-adapter",   .file = NULL },
  67                 { .subsystem = "pci_bus",       .file = NULL },
  68                 { .subsystem = "ieee1394",      .file = NULL },
  69                 { .subsystem = "ieee1394_host", .file = NULL },
  70                 { .subsystem = "ieee1394_node", .file = NULL },
  71                 { NULL, NULL }
  72         };
  73         struct class_file *classfile;
  74         const char *file = "dev";
  75         int loop;
  76
  77         /* look if we want to look for another file instead of "dev" */
  78         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  79                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  80                         if (classfile->file == NULL) {
  81                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  82                                 return 0;
  83                         }
  84                         file = classfile->file;
  85                         break;
  86                 }
  87         }
  88         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
  89
  90         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
  91         while (--loop) {
  92                 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
  93                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
  94                         return 0;
  95                 }
  96
  97                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
  98         }
  99
 100         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 101         return -1;
 102 }
 103
 104 /* skip waiting for physical device */
 105 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 106 {
 107         /* List of devices without a "device" symlink
 108          * set .device to NULL to accept all devices in that subsystem */
 109         static struct class_device {
 110                 char *subsystem;
 111                 char *device;
 112         } class_device[] = {
 113                 { .subsystem = "block",         .device = "double" },
 114                 { .subsystem = "block",         .device = "nb" },
 115                 { .subsystem = "block",         .device = "ram" },
 116                 { .subsystem = "block",         .device = "loop" },
 117                 { .subsystem = "block",         .device = "fd" },
 118                 { .subsystem = "block",         .device = "md" },
 119                 { .subsystem = "block",         .device = "dos_cd" },
 120                 { .subsystem = "block",         .device = "rflash" },
 121                 { .subsystem = "block",         .device = "rom" },
 122                 { .subsystem = "block",         .device = "rrom" },
 123                 { .subsystem = "block",         .device = "flash" },
 124                 { .subsystem = "block",         .device = "msd" },
 125                 { .subsystem = "block",         .device = "sbpcd" },
 126                 { .subsystem = "block",         .device = "pcd" },
 127                 { .subsystem = "block",         .device = "pf" },
 128                 { .subsystem = "block",         .device = "scd" },
 129                 { .subsystem = "block",         .device = "ubd" },
 130                 { .subsystem = "input",         .device = "event" },
 131                 { .subsystem = "input",         .device = "mice" },
 132                 { .subsystem = "input",         .device = "mouse" },
 133                 { .subsystem = "input",         .device = "ts" },
 134                 { .subsystem = "vc",            .device = NULL },
 135                 { .subsystem = "tty",           .device = NULL },
 136                 { .subsystem = "cpuid",         .device = "cpu" },
 137                 { .subsystem = "graphics",      .device = "fb" },
 138                 { .subsystem = "mem",           .device = NULL },
 139                 { .subsystem = "misc",          .device = NULL },
 140                 { .subsystem = "msr",           .device = NULL },
 141                 { .subsystem = "netlink",       .device = NULL },
 142                 { .subsystem = "net",           .device = "sit" },
 143                 { .subsystem = "net",           .device = "ppp" },
 144                 { .subsystem = "net",           .device = "lo" },
 145                 { .subsystem = "net",           .device = "tap" },
 146                 { .subsystem = "sound",         .device = NULL },
 147                 { .subsystem = "printer",       .device = "lp" },
 148                 { .subsystem = "nvidia",        .device = NULL },
 149                 { .subsystem = "video4linux",   .device = "vbi" },
 150                 { .subsystem = "lirc",          .device = NULL },
 151                 { .subsystem = "firmware",      .device = NULL },
 152                 { .subsystem = "drm",           .device = NULL },
 153                 { .subsystem = "pci_bus",       .device = NULL },
 154                 { .subsystem = "ieee1394",      .device = NULL },
 155                 { .subsystem = "ieee1394_host", .device = NULL },
 156                 { .subsystem = "ieee1394_node", .device = NULL },
 157                 { NULL, NULL }
 158         };
 159         struct class_device *classdevice;
 160         int len;
 161
 162         /* look if we want to look for another file instead of "dev" */
 163         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 164                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 165                         /* if device is NULL, all devices in this class are ok */
 166                         if (classdevice->device == NULL)
 167                                 return 1;
 168
 169                         len = strlen(classdevice->device);
 170
 171                         /* see if device name matches */
 172                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 173                                 continue;
 174
 175                         /* exact match */
 176                         if (strlen(class_dev->name) == len)
 177                                 return 1;
 178
 179                         /* instance numbers are matching too */
 180                         if (isdigit(class_dev->name[len]))
 181                                 return 1;
 182                 }
 183         }
 184
 185         return 0;
 186 }
 187
 188 /* skip waiting for the bus */
 189 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 190 {
 191         static char *devices_without_bus[] = {
 192                 "scsi_host",
 193                 "i2c-adapter",
 194                 NULL
 195         };
 196         char **device;
 197
 198         for (device = devices_without_bus; *device != NULL; device++) {
 199                 int len = strlen(*device);
 200
 201                 if (strncmp(class_dev->classname, *device, len) == 0)
 202                         return 1;
 203         }
 204
 205         return 0;
 206 }
 207
 208 /* wait for the bus and for a bus specific file to show up */
 209 static int wait_for_bus_device(struct sysfs_device *device_dev)
 210 {
 211         static struct bus_file {
 212                 char *bus;
 213                 char *file;
 214         } bus_files[] = {
 215                 { .bus = "scsi",        .file = "vendor" },
 216                 { .bus = "usb",         .file = "idVendor" },
 217                 { .bus = "usb",         .file = "iInterface" },
 218                 { .bus = "usb",         .file = "bNumEndpoints" },
 219                 { .bus = "usb-serial",  .file = "detach_state" },
 220                 { .bus = "ide",         .file = "detach_state" },
 221                 { .bus = "pci",         .file = "vendor" },
 222                 { .bus = "platform",    .file = "detach_state" },
 223                 { .bus = "i2c",         .file = "detach_state" },
 224                 { NULL }
 225         };
 226         struct bus_file *busfile;
 227         int loop;
 228
 229         /* wait for the /bus-device link to the /device-device */
 230         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 231         while (--loop) {
 232                 if (sysfs_get_device_bus(device_dev) == 0)
 233                         break;
 234
 235                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 236         }
 237         if (loop == 0) {
 238                 dbg("error: getting /bus-device link");
 239                 return -1;
 240         }
 241         dbg("/bus-device link found for bus '%s'", device_dev->bus);
 242
 243         /* wait for a bus specific file to show up */
 244         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 245         while (--loop) {
 246                 int found = 0;
 247
 248                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 249                         if (strcmp(device_dev->bus, busfile->bus) == 0) {
 250                                 found = 1;
 251                                 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
 252                                 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
 253                                         dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
 254                                         return 0;
 255                                 }
 256                         }
 257                 }
 258                 if (found == 0) {
 259                         info("error: unknown bus, please report to "
 260                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
 261                         return -1;
 262                 }
 263                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 264         }
 265
 266         dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
 267         return -1;
 268 }
 269
 270 int main(int argc, char *argv[], char *envp[])
 271 {
 272         const char *devpath = "";
 273         const char *action;
 274         const char *subsystem;
 275         char sysfs_path[SYSFS_PATH_MAX];
 276         char filename[SYSFS_PATH_MAX];
 277         struct sysfs_class_device *class_dev;
 278         struct sysfs_class_device *class_dev_parent;
 279         struct sysfs_device *device_dev = NULL;
 280         int loop;
 281         int rc = 0;
 282
 283         init_logging("wait_for_sysfs");
 284
 285         if (argc != 2) {
 286                 dbg("error: subsystem");
 287                 return 1;
 288         }
 289         subsystem = argv[1];
 290
 291         devpath = getenv ("DEVPATH");
 292         if (!devpath) {
 293                 dbg("error: no DEVPATH");
 294                 return 1;
 295         }
 296
 297         action = getenv ("ACTION");
 298         if (!action) {
 299                 dbg("error: no ACTION");
 300                 return 1;
 301         }
 302
 303         /* we only wait on an add event */
 304         if (strcmp(action, "add") != 0)
 305                 return 0;
 306
 307         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 308                 dbg("error: no sysfs path");
 309                 return 2;
 310         }
 311
 312         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 313                 /* open the class device we are called for */
 314                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 315                 filename[SYSFS_PATH_MAX-1] = '\0';
 316
 317                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 318                 while (--loop) {
 319                         class_dev = sysfs_open_class_device_path(filename);
 320                         if (class_dev)
 321                                 break;
 322
 323                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 324                 }
 325                 if (class_dev == NULL) {
 326                         dbg("error: getting class_device");
 327                         rc = 3;
 328                         goto exit;
 329                 }
 330                 dbg("class_device opened '%s'", filename);
 331
 332                 if (wait_for_class_device_attributes(class_dev) != 0) {
 333                         rc = 4;
 334                         goto exit_class;
 335                 }
 336
 337                 /* skip devices without /device-link */
 338                 if (class_device_expect_no_device_link(class_dev)) {
 339                         dbg("no device symlink expected for '%s', ", class_dev->name);
 340                         goto exit_class;
 341                 }
 342
 343                 /* the symlink may be on the parent device */
 344                 class_dev_parent = sysfs_get_classdev_parent(class_dev);
 345                 if (class_dev_parent)
 346                         dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 347
 348                 /* wait for the symlink to the /device-device */
 349                 dbg("waiting for symlink to /device-device");
 350                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 351                 while (--loop) {
 352                         if (class_dev_parent)
 353                                 device_dev = sysfs_get_classdev_device(class_dev_parent);
 354                         else
 355                                 device_dev = sysfs_get_classdev_device(class_dev);
 356
 357                         if (device_dev)
 358                                 break;
 359
 360                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 361                 }
 362                 if (device_dev == NULL) {
 363                         dbg("error: getting /device-device");
 364                         rc = 5;
 365                         goto exit_class;
 366                 }
 367                 dbg("device symlink found pointing to '%s'", device_dev->path);
 368
 369                 /* wait for the bus value */
 370                 if (class_device_expect_no_bus(class_dev)) {
 371                         dbg("no bus device expected for '%s', ", class_dev->classname);
 372                 } else {
 373                         if (wait_for_bus_device(device_dev) != 0)
 374                                 rc = 6;
 375                 }
 376
 377 exit_class:
 378                 sysfs_close_class_device(class_dev);
 379
 380         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 381                 /* open the path we are called for */
 382                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 383                 filename[SYSFS_PATH_MAX-1] = '\0';
 384
 385                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 386                 while (--loop) {
 387                         device_dev = sysfs_open_device_path(filename);
 388                         if (device_dev)
 389                                 break;
 390
 391                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 392                 }
 393                 if (device_dev == NULL) {
 394                         dbg("error: getting /device-device");
 395                         rc = 7;
 396                         goto exit;
 397                 }
 398                 dbg("device_device opened '%s'", filename);
 399
 400                 /* wait for the bus value */
 401                 if (wait_for_bus_device(device_dev) != 0)
 402                         rc = 8;
 403
 404                 sysfs_close_device(device_dev);
 405
 406         } else {
 407                 dbg("unhandled sysfs path, no need to wait");
 408         }
 409
 410 exit:
 411         if (rc == 0)
 412                 dbg("result: waiting for sysfs successful '%s'", devpath);
 413         else
 414                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 415                      "properly (%d) or the sysfs-support of your device's driver needs to be fixed, "
 416                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 417                      UDEV_VERSION, devpath, rc);
 418
 419         return rc;
 420 }