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  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
  10  *
  11  *      This program is free software; you can redistribute it and/or modify it
  12  *      under the terms of the GNU General Public License as published by the
  13  *      Free Software Foundation version 2 of the License.
  14  *
  15  *      This program is distributed in the hope that it will be useful, but
  16  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *      General Public License for more details.
  19  *
  20  *      You should have received a copy of the GNU General Public License along
  21  *      with this program; if not, write to the Free Software Foundation, Inc.,
  22  *      675 Mass Ave, Cambridge, MA 02139, USA.
  23  *
  24  */
  25
  26 #include <stdio.h>
  27 #include <stddef.h>
  28 #include <stdlib.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <ctype.h>
  32 #include <errno.h>
  33 #include <sys/stat.h>
  34
  35 #include "logging.h"
  36 #include "udev_version.h"
  37 #include "libsysfs/sysfs/libsysfs.h"
  38
  39 #ifndef FILENAME_MAX
  40 #define FILENAME_MAX    4096
  41 #endif
  42
  43 #ifdef LOG
  44 unsigned char logname[LOGNAME_SIZE];
  45 void log_message(int level, const char *format, ...)
  46 {
  47         va_list args;
  48
  49         va_start(args, format);
  50         vsyslog(level, format, args);
  51         va_end(args);
  52 }
  53 #endif
  54
  55 #define WAIT_MAX_SECONDS                5
  56 #define WAIT_LOOP_PER_SECOND            20
  57
  58 /* wait for specific file to show up, normally the "dev"-file */
  59 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev,
  60                                             const char **error)
  61 {
  62         static struct class_file {
  63                 char *subsystem;
  64                 char *file;
  65         } class_files[] = {
  66                 { .subsystem = "net",           .file = "ifindex" },
  67                 { .subsystem = "scsi_host",     .file = "unique_id" },
  68                 { .subsystem = "scsi_device",   .file = NULL },
  69                 { .subsystem = "pcmcia_socket", .file = "card_type" },
  70                 { .subsystem = "usb_host",      .file = NULL },
  71                 { .subsystem = "bluetooth",     .file = "address" },
  72                 { .subsystem = "firmware",      .file = "data" },
  73                 { .subsystem = "i2c-adapter",   .file = NULL },
  74                 { .subsystem = "pci_bus",       .file = NULL },
  75                 { .subsystem = "ieee1394",      .file = NULL },
  76                 { .subsystem = "ieee1394_host", .file = NULL },
  77                 { .subsystem = "ieee1394_node", .file = NULL },
  78                 { NULL, NULL }
  79         };
  80         struct class_file *classfile;
  81         char *file = "dev";
  82         char filename[FILENAME_MAX];
  83         int loop;
  84
  85         /* look if we want to look for another file instead of "dev" */
  86         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  87                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  88                         if (classfile->file == NULL) {
  89                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  90                                 return 0;
  91                         }
  92                         file = classfile->file;
  93                         break;
  94                 }
  95         }
  96
  97         strcpy(filename, class_dev->path);
  98         strcat(filename, "/");
  99         strcat(filename, file);
 100         dbg("looking at class '%s' for specific file '%s' with full name %s", class_dev->classname, class_dev->path, filename);
 101
 102         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 103         while (--loop) {
 104                 struct stat stats;
 105
 106                 if (stat(class_dev->path, &stats) == -1) {
 107                         dbg("'%s' now disappeared (probably remove has beaten us)", class_dev->path);
 108                         return -ENODEV;
 109                 }
 110
 111                 if (stat(filename, &stats) == 0) {
 112                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
 113                         return 0;
 114                 }
 115
 116                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 117         }
 118
 119         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 120         *error = "class specific file unavailable";
 121         return -ENOENT;
 122 }
 123
 124 /* check if we need to wait for a physical device */
 125 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 126 {
 127         /* list of devices without a "device" symlink to the physical device
 128          * if device is set to NULL, no devices in that subsystem has a link */
 129         static struct class_device {
 130                 char *subsystem;
 131                 char *device;
 132         } class_device[] = {
 133                 { .subsystem = "block",         .device = "double" },
 134                 { .subsystem = "block",         .device = "nb" },
 135                 { .subsystem = "block",         .device = "ram" },
 136                 { .subsystem = "block",         .device = "loop" },
 137                 { .subsystem = "block",         .device = "fd" },
 138                 { .subsystem = "block",         .device = "md" },
 139                 { .subsystem = "block",         .device = "dos_cd" },
 140                 { .subsystem = "block",         .device = "rflash" },
 141                 { .subsystem = "block",         .device = "rom" },
 142                 { .subsystem = "block",         .device = "rrom" },
 143                 { .subsystem = "block",         .device = "flash" },
 144                 { .subsystem = "block",         .device = "msd" },
 145                 { .subsystem = "block",         .device = "sbpcd" },
 146                 { .subsystem = "block",         .device = "pcd" },
 147                 { .subsystem = "block",         .device = "pf" },
 148                 { .subsystem = "block",         .device = "scd" },
 149                 { .subsystem = "block",         .device = "ubd" },
 150                 { .subsystem = "input",         .device = "event" },
 151                 { .subsystem = "input",         .device = "mice" },
 152                 { .subsystem = "input",         .device = "mouse" },
 153                 { .subsystem = "input",         .device = "ts" },
 154                 { .subsystem = "vc",            .device = NULL },
 155                 { .subsystem = "tty",           .device = NULL },
 156                 { .subsystem = "cpuid",         .device = "cpu" },
 157                 { .subsystem = "graphics",      .device = "fb" },
 158                 { .subsystem = "mem",           .device = NULL },
 159                 { .subsystem = "misc",          .device = NULL },
 160                 { .subsystem = "msr",           .device = NULL },
 161                 { .subsystem = "netlink",       .device = NULL },
 162                 { .subsystem = "net",           .device = "sit" },
 163                 { .subsystem = "net",           .device = "lo" },
 164                 { .subsystem = "net",           .device = "tap" },
 165                 { .subsystem = "net",           .device = "ipsec" },
 166                 { .subsystem = "net",           .device = "dummy" },
 167                 { .subsystem = "net",           .device = "irda" },
 168                 { .subsystem = "net",           .device = "ppp" },
 169                 { .subsystem = "ppp",           .device = NULL },
 170                 { .subsystem = "sound",         .device = NULL },
 171                 { .subsystem = "printer",       .device = "lp" },
 172                 { .subsystem = "nvidia",        .device = NULL },
 173                 { .subsystem = "video4linux",   .device = "vbi" },
 174                 { .subsystem = "lirc",          .device = NULL },
 175                 { .subsystem = "firmware",      .device = NULL },
 176                 { .subsystem = "drm",           .device = NULL },
 177                 { .subsystem = "pci_bus",       .device = NULL },
 178                 { .subsystem = "ieee1394",      .device = NULL },
 179                 { .subsystem = "ieee1394_host", .device = NULL },
 180                 { .subsystem = "ieee1394_node", .device = NULL },
 181                 { .subsystem = "raw",           .device = NULL },
 182                 { NULL, NULL }
 183         };
 184         struct class_device *classdevice;
 185         int len;
 186
 187         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 188                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 189                         /* see if no device in this class is expected to have a device-link */
 190                         if (classdevice->device == NULL)
 191                                 return 1;
 192
 193                         len = strlen(classdevice->device);
 194
 195                         /* see if device name matches */
 196                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 197                                 continue;
 198
 199                         /* exact name match */
 200                         if (strlen(class_dev->name) == len)
 201                                 return 1;
 202
 203                         /* name match with instance number */
 204                         if (isdigit(class_dev->name[len]))
 205                                 return 1;
 206                 }
 207         }
 208
 209         return 0;
 210 }
 211
 212 /* skip waiting for the bus */
 213 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 214 {
 215         static char *devices_without_bus[] = {
 216                 "scsi_host",
 217                 "i2c-adapter",
 218                 NULL
 219         };
 220         char **device;
 221
 222         for (device = devices_without_bus; *device != NULL; device++) {
 223                 int len = strlen(*device);
 224
 225                 if (strncmp(class_dev->classname, *device, len) == 0)
 226                         return 1;
 227         }
 228
 229         return 0;
 230 }
 231
 232 /* wait for the bus and for a bus specific file to show up */
 233 static int wait_for_bus_device(struct sysfs_device *devices_dev,
 234                                const char **error)
 235 {
 236         static struct bus_file {
 237                 char *bus;
 238                 char *file;
 239         } bus_files[] = {
 240                 { .bus = "scsi",        .file = "vendor" },
 241                 { .bus = "usb",         .file = "idVendor" },
 242                 { .bus = "usb",         .file = "iInterface" },
 243                 { .bus = "usb",         .file = "bNumEndpoints" },
 244                 { .bus = "usb-serial",  .file = "detach_state" },
 245                 { .bus = "ide",         .file = "detach_state" },
 246                 { .bus = "pci",         .file = "vendor" },
 247                 { .bus = "platform",    .file = "detach_state" },
 248                 { .bus = "i2c",         .file = "detach_state" },
 249                 { NULL }
 250         };
 251         struct bus_file *busfile;
 252         int loop;
 253
 254         /* wait for the bus device link to the devices device */
 255         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 256         while (--loop) {
 257                 if (sysfs_get_device_bus(devices_dev) == 0)
 258                         break;
 259
 260                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 261         }
 262         if (loop == 0) {
 263                 dbg("error: getting bus device link");
 264                 *error = "no bus device link";
 265                 return -1;
 266         }
 267         dbg("bus device link found for bus '%s'", devices_dev->bus);
 268
 269         /* wait for a bus specific file to show up */
 270         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 271         while (--loop) {
 272                 int found = 0;
 273
 274                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 275                         if (strcmp(devices_dev->bus, busfile->bus) == 0) {
 276                                 found = 1;
 277                                 dbg("looking at bus '%s' for specific file '%s'", devices_dev->bus, busfile->file);
 278                                 if (sysfs_get_device_attr(devices_dev, busfile->file) != NULL) {
 279                                         dbg("bus '%s' specific file '%s' found", devices_dev->bus, busfile->file);
 280                                         return 0;
 281                                 }
 282                         }
 283                 }
 284                 if (found == 0) {
 285                         *error = "unknown bus";
 286                         info("error: unknown bus, please report to "
 287                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
 288                         return -1;
 289                 }
 290                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 291         }
 292
 293         dbg("error: getting bus '%s' specific file '%s'", devices_dev->bus, busfile->file);
 294         *error = "bus specific file unavailable";
 295         return -1;
 296 }
 297
 298
 299 static struct sysfs_class_device *open_class_device(const char *path)
 300 {
 301         struct sysfs_class_device *class_dev;
 302         int loop;
 303
 304         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 305         while (--loop) {
 306                 class_dev = sysfs_open_class_device_path(path);
 307                 if (class_dev)
 308                         break;
 309
 310                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 311         }
 312
 313         return (class_dev);
 314 }
 315
 316 static int wait_for_class_device(struct sysfs_class_device *class_dev,
 317                                  const char **error)
 318 {
 319         struct sysfs_class_device *class_dev_parent;
 320         struct sysfs_device *devices_dev = NULL;
 321         int loop;
 322
 323         if (wait_for_class_device_attributes(class_dev, error) != 0)
 324                 return -ENOENT;
 325
 326         /* skip devices without devices-link */
 327         if (class_device_expect_no_device_link(class_dev)) {
 328                 dbg("no device symlink expected for '%s', ", class_dev->name);
 329                 return -ENODEV;
 330         }
 331
 332         /* the symlink may be on the parent device */
 333         class_dev_parent = sysfs_get_classdev_parent(class_dev);
 334         if (class_dev_parent)
 335                 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 336
 337         /* wait for the symlink to the devices device */
 338         dbg("waiting for symlink to devices device");
 339         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 340         while (--loop) {
 341                 if (class_dev_parent)
 342                         devices_dev = sysfs_get_classdev_device(class_dev_parent);
 343                 else
 344                         devices_dev = sysfs_get_classdev_device(class_dev);
 345
 346                 if (devices_dev)
 347                         break;
 348
 349                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 350         }
 351         if (!devices_dev) {
 352                 dbg(" error: no devices device symlink found");
 353                 *error = "no device symlink";
 354                 return -ENODEV;
 355         }
 356         dbg("device symlink found pointing to '%s'", devices_dev->path);
 357
 358         /* wait for the bus value */
 359         if (class_device_expect_no_bus(class_dev)) {
 360                 dbg("no bus device expected for '%s', ", class_dev->classname);
 361                 return 0;
 362         } else {
 363                 return wait_for_bus_device(devices_dev, error);
 364         }
 365 }
 366
 367 static struct sysfs_device *open_devices_device(const char *path)
 368 {
 369         struct sysfs_device *devices_dev;
 370         int loop;
 371
 372         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 373         while (--loop) {
 374                 devices_dev = sysfs_open_device_path(path);
 375                 if (devices_dev)
 376                         break;
 377
 378                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 379         }
 380
 381         return(devices_dev);
 382 }
 383
 384 int main(int argc, char *argv[], char *envp[])
 385 {
 386         const char *devpath = "";
 387         const char *action;
 388         const char *subsystem;
 389         char sysfs_path[SYSFS_PATH_MAX];
 390         char filename[SYSFS_PATH_MAX];
 391         struct sysfs_class_device *class_dev;
 392         struct sysfs_device *devices_dev;
 393         int rc = 0;
 394         const char *error = NULL;
 395
 396         logging_init("wait_for_sysfs");
 397
 398         if (argc != 2) {
 399                 dbg("error: subsystem");
 400                 return 1;
 401         }
 402         subsystem = argv[1];
 403
 404         devpath = getenv ("DEVPATH");
 405         if (!devpath) {
 406                 dbg("error: no DEVPATH");
 407                 rc = 1;
 408                 goto exit;
 409         }
 410
 411         action = getenv ("ACTION");
 412         if (!action) {
 413                 dbg("error: no ACTION");
 414                 rc = 1;
 415                 goto exit;
 416         }
 417
 418         /* we only wait on an add event */
 419         if (strcmp(action, "add") != 0) {
 420                 dbg("no add ACTION");
 421                 goto exit;
 422         }
 423
 424         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 425                 dbg("error: no sysfs path");
 426                 rc = 2;
 427                 goto exit;
 428         }
 429
 430         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 431                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 432                 filename[SYSFS_PATH_MAX-1] = '\0';
 433
 434                 /* open the class device we are called for */
 435                 class_dev = open_class_device(filename);
 436                 if (!class_dev) {
 437                         dbg("error: class device unavailable (probably remove has beaten us)");
 438                         goto exit;
 439                 }
 440                 dbg("class device opened '%s'", filename);
 441
 442                 /* wait for the class device with possible physical device and bus */
 443                 wait_for_class_device(class_dev, &error);
 444
 445                 sysfs_close_class_device(class_dev);
 446
 447         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 448                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 449                 filename[SYSFS_PATH_MAX-1] = '\0';
 450
 451                 /* open the path we are called for */
 452                 devices_dev = open_devices_device(filename);
 453                 if (!devices_dev) {
 454                         dbg("error: devices device unavailable (probably remove has beaten us)");
 455                         goto exit;
 456                 }
 457                 dbg("devices device opened '%s'", filename);
 458
 459                 /* wait for the bus value */
 460                 wait_for_bus_device(devices_dev, &error);
 461
 462                 sysfs_close_device(devices_dev);
 463
 464         } else {
 465                 dbg("unhandled sysfs path, no need to wait");
 466         }
 467
 468 exit:
 469         if (error) {
 470                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 471                      "properly (%s) or the sysfs-support of your device's driver needs to be fixed, "
 472                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 473                      UDEV_VERSION, devpath, error);
 474                 rc =3;
 475         } else {
 476                 dbg("result: waiting for sysfs successful '%s'", devpath);
 477         }
 478
 479         logging_close();
 480         exit(rc);
 481 }