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 = "block",         .device = "dm-" },
 151                 { .subsystem = "input",         .device = "event" },
 152                 { .subsystem = "input",         .device = "mice" },
 153                 { .subsystem = "input",         .device = "mouse" },
 154                 { .subsystem = "input",         .device = "ts" },
 155                 { .subsystem = "vc",            .device = NULL },
 156                 { .subsystem = "tty",           .device = NULL },
 157                 { .subsystem = "cpuid",         .device = "cpu" },
 158                 { .subsystem = "graphics",      .device = "fb" },
 159                 { .subsystem = "mem",           .device = NULL },
 160                 { .subsystem = "misc",          .device = NULL },
 161                 { .subsystem = "msr",           .device = NULL },
 162                 { .subsystem = "netlink",       .device = NULL },
 163                 { .subsystem = "net",           .device = "sit" },
 164                 { .subsystem = "net",           .device = "lo" },
 165                 { .subsystem = "net",           .device = "tap" },
 166                 { .subsystem = "net",           .device = "ipsec" },
 167                 { .subsystem = "net",           .device = "dummy" },
 168                 { .subsystem = "net",           .device = "irda" },
 169                 { .subsystem = "net",           .device = "ppp" },
 170                 { .subsystem = "ppp",           .device = NULL },
 171                 { .subsystem = "sound",         .device = NULL },
 172                 { .subsystem = "printer",       .device = "lp" },
 173                 { .subsystem = "nvidia",        .device = NULL },
 174                 { .subsystem = "video4linux",   .device = "vbi" },
 175                 { .subsystem = "lirc",          .device = NULL },
 176                 { .subsystem = "firmware",      .device = NULL },
 177                 { .subsystem = "drm",           .device = NULL },
 178                 { .subsystem = "pci_bus",       .device = NULL },
 179                 { .subsystem = "ieee1394",      .device = NULL },
 180                 { .subsystem = "ieee1394_host", .device = NULL },
 181                 { .subsystem = "ieee1394_node", .device = NULL },
 182                 { .subsystem = "raw",           .device = NULL },
 183                 { NULL, NULL }
 184         };
 185         struct class_device *classdevice;
 186         int len;
 187
 188         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 189                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 190                         /* see if no device in this class is expected to have a device-link */
 191                         if (classdevice->device == NULL)
 192                                 return 1;
 193
 194                         len = strlen(classdevice->device);
 195
 196                         /* see if device name matches */
 197                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 198                                 continue;
 199
 200                         /* exact name match */
 201                         if (strlen(class_dev->name) == len)
 202                                 return 1;
 203
 204                         /* name match with instance number */
 205                         if (isdigit(class_dev->name[len]))
 206                                 return 1;
 207                 }
 208         }
 209
 210         return 0;
 211 }
 212
 213 /* skip waiting for the bus */
 214 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 215 {
 216         static char *devices_without_bus[] = {
 217                 "scsi_host",
 218                 "i2c-adapter",
 219                 NULL
 220         };
 221         char **device;
 222
 223         for (device = devices_without_bus; *device != NULL; device++) {
 224                 int len = strlen(*device);
 225
 226                 if (strncmp(class_dev->classname, *device, len) == 0)
 227                         return 1;
 228         }
 229
 230         return 0;
 231 }
 232
 233 /* wait for the bus and for a bus specific file to show up */
 234 static int wait_for_bus_device(struct sysfs_device *devices_dev,
 235                                const char **error)
 236 {
 237         static struct bus_file {
 238                 char *bus;
 239                 char *file;
 240         } bus_files[] = {
 241                 { .bus = "scsi",        .file = "vendor" },
 242                 { .bus = "usb",         .file = "idVendor" },
 243                 { .bus = "usb",         .file = "iInterface" },
 244                 { .bus = "usb",         .file = "bNumEndpoints" },
 245                 { .bus = "usb-serial",  .file = "detach_state" },
 246                 { .bus = "ide",         .file = "detach_state" },
 247                 { .bus = "pci",         .file = "vendor" },
 248                 { .bus = "platform",    .file = "detach_state" },
 249                 { .bus = "i2c",         .file = "detach_state" },
 250                 { NULL }
 251         };
 252         struct bus_file *busfile;
 253         int loop;
 254
 255         /* wait for the bus device link to the devices device */
 256         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 257         while (--loop) {
 258                 if (sysfs_get_device_bus(devices_dev) == 0)
 259                         break;
 260
 261                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 262         }
 263         if (loop == 0) {
 264                 dbg("error: getting bus device link");
 265                 *error = "no bus device link";
 266                 return -1;
 267         }
 268         dbg("bus device link found for bus '%s'", devices_dev->bus);
 269
 270         /* wait for a bus specific file to show up */
 271         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 272         while (--loop) {
 273                 int found = 0;
 274
 275                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 276                         if (strcmp(devices_dev->bus, busfile->bus) == 0) {
 277                                 found = 1;
 278                                 dbg("looking at bus '%s' for specific file '%s'", devices_dev->bus, busfile->file);
 279                                 if (sysfs_get_device_attr(devices_dev, busfile->file) != NULL) {
 280                                         dbg("bus '%s' specific file '%s' found", devices_dev->bus, busfile->file);
 281                                         return 0;
 282                                 }
 283                         }
 284                 }
 285                 if (found == 0) {
 286                         *error = "unknown bus";
 287                         info("error: unknown bus, please report to "
 288                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
 289                         return -1;
 290                 }
 291                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 292         }
 293
 294         dbg("error: getting bus '%s' specific file '%s'", devices_dev->bus, busfile->file);
 295         *error = "bus specific file unavailable";
 296         return -1;
 297 }
 298
 299
 300 static struct sysfs_class_device *open_class_device(const char *path)
 301 {
 302         struct sysfs_class_device *class_dev;
 303         int loop;
 304
 305         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 306         while (--loop) {
 307                 class_dev = sysfs_open_class_device_path(path);
 308                 if (class_dev)
 309                         break;
 310
 311                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 312         }
 313
 314         return (class_dev);
 315 }
 316
 317 static int wait_for_class_device(struct sysfs_class_device *class_dev,
 318                                  const char **error)
 319 {
 320         struct sysfs_class_device *class_dev_parent;
 321         struct sysfs_device *devices_dev = NULL;
 322         int loop;
 323
 324         if (wait_for_class_device_attributes(class_dev, error) != 0)
 325                 return -ENOENT;
 326
 327         /* skip devices without devices-link */
 328         if (class_device_expect_no_device_link(class_dev)) {
 329                 dbg("no device symlink expected for '%s', ", class_dev->name);
 330                 return -ENODEV;
 331         }
 332
 333         /* the symlink may be on the parent device */
 334         class_dev_parent = sysfs_get_classdev_parent(class_dev);
 335         if (class_dev_parent)
 336                 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 337
 338         /* wait for the symlink to the devices device */
 339         dbg("waiting for symlink to devices device");
 340         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 341         while (--loop) {
 342                 if (class_dev_parent)
 343                         devices_dev = sysfs_get_classdev_device(class_dev_parent);
 344                 else
 345                         devices_dev = sysfs_get_classdev_device(class_dev);
 346
 347                 if (devices_dev)
 348                         break;
 349
 350                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 351         }
 352         if (!devices_dev) {
 353                 dbg(" error: no devices device symlink found");
 354                 *error = "no device symlink";
 355                 return -ENODEV;
 356         }
 357         dbg("device symlink found pointing to '%s'", devices_dev->path);
 358
 359         /* wait for the bus value */
 360         if (class_device_expect_no_bus(class_dev)) {
 361                 dbg("no bus device expected for '%s', ", class_dev->classname);
 362                 return 0;
 363         } else {
 364                 return wait_for_bus_device(devices_dev, error);
 365         }
 366 }
 367
 368 static struct sysfs_device *open_devices_device(const char *path)
 369 {
 370         struct sysfs_device *devices_dev;
 371         int loop;
 372
 373         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 374         while (--loop) {
 375                 devices_dev = sysfs_open_device_path(path);
 376                 if (devices_dev)
 377                         break;
 378
 379                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 380         }
 381
 382         return(devices_dev);
 383 }
 384
 385 int main(int argc, char *argv[], char *envp[])
 386 {
 387         const char *devpath = "";
 388         const char *action;
 389         const char *subsystem;
 390         char sysfs_mnt_path[SYSFS_PATH_MAX];
 391         char filename[SYSFS_PATH_MAX];
 392         struct sysfs_class_device *class_dev;
 393         struct sysfs_device *devices_dev;
 394         int rc = 0;
 395         const char *error = NULL;
 396
 397         logging_init("wait_for_sysfs");
 398
 399         if (argc != 2) {
 400                 dbg("error: subsystem");
 401                 return 1;
 402         }
 403         subsystem = argv[1];
 404
 405         devpath = getenv ("DEVPATH");
 406         if (!devpath) {
 407                 dbg("error: no DEVPATH");
 408                 rc = 1;
 409                 goto exit;
 410         }
 411
 412         action = getenv ("ACTION");
 413         if (!action) {
 414                 dbg("error: no ACTION");
 415                 rc = 1;
 416                 goto exit;
 417         }
 418
 419         /* we only wait on an add event */
 420         if (strcmp(action, "add") != 0) {
 421                 dbg("no add ACTION");
 422                 goto exit;
 423         }
 424
 425         if (sysfs_get_mnt_path(sysfs_mnt_path, SYSFS_PATH_MAX) != 0) {
 426                 dbg("error: no sysfs path");
 427                 rc = 2;
 428                 goto exit;
 429         }
 430
 431         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 432                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_mnt_path, devpath);
 433                 filename[SYSFS_PATH_MAX-1] = '\0';
 434
 435                 /* open the class device we are called for */
 436                 class_dev = open_class_device(filename);
 437                 if (!class_dev) {
 438                         dbg("error: class device unavailable (probably remove has beaten us)");
 439                         goto exit;
 440                 }
 441                 dbg("class device opened '%s'", filename);
 442
 443                 /* wait for the class device with possible physical device and bus */
 444                 wait_for_class_device(class_dev, &error);
 445
 446                 sysfs_close_class_device(class_dev);
 447
 448         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 449                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_mnt_path, devpath);
 450                 filename[SYSFS_PATH_MAX-1] = '\0';
 451
 452                 /* open the path we are called for */
 453                 devices_dev = open_devices_device(filename);
 454                 if (!devices_dev) {
 455                         dbg("error: devices device unavailable (probably remove has beaten us)");
 456                         goto exit;
 457                 }
 458                 dbg("devices device opened '%s'", filename);
 459
 460                 /* wait for the bus value */
 461                 wait_for_bus_device(devices_dev, &error);
 462
 463                 sysfs_close_device(devices_dev);
 464
 465         } else {
 466                 dbg("unhandled sysfs path, no need to wait");
 467         }
 468
 469 exit:
 470         if (error) {
 471                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 472                      "properly (%s) or the sysfs-support of your device's driver needs to be fixed, "
 473                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 474                      UDEV_VERSION, devpath, error);
 475                 rc =3;
 476         } else {
 477                 dbg("result: waiting for sysfs successful '%s'", devpath);
 478         }
 479
 480         logging_close();
 481         exit(rc);
 482 }