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 {
  61         static struct class_file {
  62                 char *subsystem;
  63                 char *file;
  64         } class_files[] = {
  65                 { .subsystem = "net",           .file = "ifindex" },
  66                 { .subsystem = "scsi_host",     .file = "unique_id" },
  67                 { .subsystem = "scsi_device",   .file = NULL },
  68                 { .subsystem = "pcmcia_socket", .file = "card_type" },
  69                 { .subsystem = "usb_host",      .file = NULL },
  70                 { .subsystem = "bluetooth",     .file = "address" },
  71                 { .subsystem = "firmware",      .file = "data" },
  72                 { .subsystem = "i2c-adapter",   .file = NULL },
  73                 { .subsystem = "pci_bus",       .file = NULL },
  74                 { .subsystem = "ieee1394",      .file = NULL },
  75                 { .subsystem = "ieee1394_host", .file = NULL },
  76                 { .subsystem = "ieee1394_node", .file = NULL },
  77                 { NULL, NULL }
  78         };
  79         struct class_file *classfile;
  80         const char *file = "dev";
  81         char filename[FILENAME_MAX];
  82         int loop;
  83
  84         /* look if we want to look for another file instead of "dev" */
  85         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  86                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  87                         if (classfile->file == NULL) {
  88                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  89                                 return 0;
  90                         }
  91                         file = classfile->file;
  92                         break;
  93                 }
  94         }
  95
  96         strcpy(filename, class_dev->path);
  97         strcat(filename, "/");
  98         strcat(filename, file);
  99         dbg("looking at class '%s' for specific file '%s' with full name %s", class_dev->classname, class_dev->path, filename);
 100
 101         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 102         while (--loop) {
 103                 struct stat stats;
 104
 105                 if (stat(class_dev->path, &stats) == -1) {
 106                         dbg("oops, the directory '%s' just disappeared.", class_dev->path);
 107                         return -ENODEV;
 108                 }
 109
 110                 if (stat(filename, &stats) == 0) {
 111                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
 112                         return 0;
 113                 }
 114
 115                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 116         }
 117
 118         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 119         return -ENOENT;
 120 }
 121
 122 /* check if we need to wait for a physical device */
 123 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 124 {
 125         /* list of devices without a "device" symlink to the physical device
 126          * if device is set to NULL, no devices in that subsystem has a link */
 127         static struct class_device {
 128                 char *subsystem;
 129                 char *device;
 130         } class_device[] = {
 131                 { .subsystem = "block",         .device = "double" },
 132                 { .subsystem = "block",         .device = "nb" },
 133                 { .subsystem = "block",         .device = "ram" },
 134                 { .subsystem = "block",         .device = "loop" },
 135                 { .subsystem = "block",         .device = "fd" },
 136                 { .subsystem = "block",         .device = "md" },
 137                 { .subsystem = "block",         .device = "dos_cd" },
 138                 { .subsystem = "block",         .device = "rflash" },
 139                 { .subsystem = "block",         .device = "rom" },
 140                 { .subsystem = "block",         .device = "rrom" },
 141                 { .subsystem = "block",         .device = "flash" },
 142                 { .subsystem = "block",         .device = "msd" },
 143                 { .subsystem = "block",         .device = "sbpcd" },
 144                 { .subsystem = "block",         .device = "pcd" },
 145                 { .subsystem = "block",         .device = "pf" },
 146                 { .subsystem = "block",         .device = "scd" },
 147                 { .subsystem = "block",         .device = "ubd" },
 148                 { .subsystem = "input",         .device = "event" },
 149                 { .subsystem = "input",         .device = "mice" },
 150                 { .subsystem = "input",         .device = "mouse" },
 151                 { .subsystem = "input",         .device = "ts" },
 152                 { .subsystem = "vc",            .device = NULL },
 153                 { .subsystem = "tty",           .device = NULL },
 154                 { .subsystem = "cpuid",         .device = "cpu" },
 155                 { .subsystem = "graphics",      .device = "fb" },
 156                 { .subsystem = "mem",           .device = NULL },
 157                 { .subsystem = "misc",          .device = NULL },
 158                 { .subsystem = "msr",           .device = NULL },
 159                 { .subsystem = "netlink",       .device = NULL },
 160                 { .subsystem = "net",           .device = "sit" },
 161                 { .subsystem = "net",           .device = "ppp" },
 162                 { .subsystem = "net",           .device = "lo" },
 163                 { .subsystem = "net",           .device = "tap" },
 164                 { .subsystem = "net",           .device = "ipsec" },
 165                 { .subsystem = "net",           .device = "irda" },
 166                 { .subsystem = "sound",         .device = NULL },
 167                 { .subsystem = "printer",       .device = "lp" },
 168                 { .subsystem = "nvidia",        .device = NULL },
 169                 { .subsystem = "video4linux",   .device = "vbi" },
 170                 { .subsystem = "lirc",          .device = NULL },
 171                 { .subsystem = "firmware",      .device = NULL },
 172                 { .subsystem = "drm",           .device = NULL },
 173                 { .subsystem = "pci_bus",       .device = NULL },
 174                 { .subsystem = "ieee1394",      .device = NULL },
 175                 { .subsystem = "ieee1394_host", .device = NULL },
 176                 { .subsystem = "ieee1394_node", .device = NULL },
 177                 { .subsystem = "raw",           .device = NULL },
 178                 { NULL, NULL }
 179         };
 180         struct class_device *classdevice;
 181         int len;
 182
 183         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 184                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 185                         /* see if no device in this class is expected to have a device-link */
 186                         if (classdevice->device == NULL)
 187                                 return 1;
 188
 189                         len = strlen(classdevice->device);
 190
 191                         /* see if device name matches */
 192                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 193                                 continue;
 194
 195                         /* exact name match */
 196                         if (strlen(class_dev->name) == len)
 197                                 return 1;
 198
 199                         /* name match with instance number */
 200                         if (isdigit(class_dev->name[len]))
 201                                 return 1;
 202                 }
 203         }
 204
 205         return 0;
 206 }
 207
 208 /* skip waiting for the bus */
 209 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 210 {
 211         static char *devices_without_bus[] = {
 212                 "scsi_host",
 213                 "i2c-adapter",
 214                 NULL
 215         };
 216         char **device;
 217
 218         for (device = devices_without_bus; *device != NULL; device++) {
 219                 int len = strlen(*device);
 220
 221                 if (strncmp(class_dev->classname, *device, len) == 0)
 222                         return 1;
 223         }
 224
 225         return 0;
 226 }
 227
 228 /* wait for the bus and for a bus specific file to show up */
 229 static int wait_for_bus_device(struct sysfs_device *device_dev)
 230 {
 231         static struct bus_file {
 232                 char *bus;
 233                 char *file;
 234         } bus_files[] = {
 235                 { .bus = "scsi",        .file = "vendor" },
 236                 { .bus = "usb",         .file = "idVendor" },
 237                 { .bus = "usb",         .file = "iInterface" },
 238                 { .bus = "usb",         .file = "bNumEndpoints" },
 239                 { .bus = "usb-serial",  .file = "detach_state" },
 240                 { .bus = "ide",         .file = "detach_state" },
 241                 { .bus = "pci",         .file = "vendor" },
 242                 { .bus = "platform",    .file = "detach_state" },
 243                 { .bus = "i2c",         .file = "detach_state" },
 244                 { NULL }
 245         };
 246         struct bus_file *busfile;
 247         int loop;
 248
 249         /* wait for the /bus-device link to the /device-device */
 250         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 251         while (--loop) {
 252                 if (sysfs_get_device_bus(device_dev) == 0)
 253                         break;
 254
 255                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 256         }
 257         if (loop == 0) {
 258                 dbg("error: getting /bus-device link");
 259                 return -1;
 260         }
 261         dbg("/bus-device link found for bus '%s'", device_dev->bus);
 262
 263         /* wait for a bus specific file to show up */
 264         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 265         while (--loop) {
 266                 int found = 0;
 267
 268                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 269                         if (strcmp(device_dev->bus, busfile->bus) == 0) {
 270                                 found = 1;
 271                                 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
 272                                 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
 273                                         dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
 274                                         return 0;
 275                                 }
 276                         }
 277                 }
 278                 if (found == 0) {
 279                         info("error: unknown bus, please report to "
 280                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
 281                         return -1;
 282                 }
 283                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 284         }
 285
 286         dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
 287         return -1;
 288 }
 289
 290 int main(int argc, char *argv[], char *envp[])
 291 {
 292         const char *devpath = "";
 293         const char *action;
 294         const char *subsystem;
 295         char sysfs_path[SYSFS_PATH_MAX];
 296         char filename[SYSFS_PATH_MAX];
 297         struct sysfs_class_device *class_dev;
 298         struct sysfs_class_device *class_dev_parent;
 299         struct sysfs_device *device_dev = NULL;
 300         int loop;
 301         int retval;
 302         int rc = 0;
 303
 304         init_logging("wait_for_sysfs");
 305
 306         if (argc != 2) {
 307                 dbg("error: subsystem");
 308                 return 1;
 309         }
 310         subsystem = argv[1];
 311
 312         devpath = getenv ("DEVPATH");
 313         if (!devpath) {
 314                 dbg("error: no DEVPATH");
 315                 return 1;
 316         }
 317
 318         action = getenv ("ACTION");
 319         if (!action) {
 320                 dbg("error: no ACTION");
 321                 return 1;
 322         }
 323
 324         /* we only wait on an add event */
 325         if (strcmp(action, "add") != 0)
 326                 return 0;
 327
 328         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 329                 dbg("error: no sysfs path");
 330                 return 2;
 331         }
 332
 333         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 334                 /* open the class device we are called for */
 335                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 336                 filename[SYSFS_PATH_MAX-1] = '\0';
 337
 338                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 339                 while (--loop) {
 340                         class_dev = sysfs_open_class_device_path(filename);
 341                         if (class_dev)
 342                                 break;
 343
 344                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 345                 }
 346                 if (class_dev == NULL) {
 347                         dbg("error: getting class_device");
 348                         rc = 3;
 349                         goto exit;
 350                 }
 351                 dbg("class_device opened '%s'", filename);
 352
 353                 retval = wait_for_class_device_attributes(class_dev);
 354                 if (retval == -ENODEV)
 355                         goto exit_class;
 356                 if (retval != 0) {
 357                         rc = 4;
 358                         goto exit_class;
 359                 }
 360
 361                 /* skip devices without /device-link */
 362                 if (class_device_expect_no_device_link(class_dev)) {
 363                         dbg("no device symlink expected for '%s', ", class_dev->name);
 364                         goto exit_class;
 365                 }
 366
 367                 /* the symlink may be on the parent device */
 368                 class_dev_parent = sysfs_get_classdev_parent(class_dev);
 369                 if (class_dev_parent)
 370                         dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 371
 372                 /* wait for the symlink to the /device-device */
 373                 dbg("waiting for symlink to /device-device");
 374                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 375                 while (--loop) {
 376                         if (class_dev_parent)
 377                                 device_dev = sysfs_get_classdev_device(class_dev_parent);
 378                         else
 379                                 device_dev = sysfs_get_classdev_device(class_dev);
 380
 381                         if (device_dev)
 382                                 break;
 383
 384                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 385                 }
 386                 if (device_dev == NULL) {
 387                         dbg("error: getting /device-device");
 388                         rc = 5;
 389                         goto exit_class;
 390                 }
 391                 dbg("device symlink found pointing to '%s'", device_dev->path);
 392
 393                 /* wait for the bus value */
 394                 if (class_device_expect_no_bus(class_dev)) {
 395                         dbg("no bus device expected for '%s', ", class_dev->classname);
 396                 } else {
 397                         if (wait_for_bus_device(device_dev) != 0)
 398                                 rc = 6;
 399                 }
 400
 401 exit_class:
 402                 sysfs_close_class_device(class_dev);
 403
 404         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 405                 /* open the path we are called for */
 406                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 407                 filename[SYSFS_PATH_MAX-1] = '\0';
 408
 409                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 410                 while (--loop) {
 411                         device_dev = sysfs_open_device_path(filename);
 412                         if (device_dev)
 413                                 break;
 414
 415                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 416                 }
 417                 if (device_dev == NULL) {
 418                         dbg("error: getting /device-device");
 419                         rc = 7;
 420                         goto exit;
 421                 }
 422                 dbg("device_device opened '%s'", filename);
 423
 424                 /* wait for the bus value */
 425                 if (wait_for_bus_device(device_dev) != 0)
 426                         rc = 8;
 427
 428                 sysfs_close_device(device_dev);
 429
 430         } else {
 431                 dbg("unhandled sysfs path, no need to wait");
 432         }
 433
 434 exit:
 435         if (rc == 0)
 436                 dbg("result: waiting for sysfs successful '%s'", devpath);
 437         else
 438                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 439                      "properly (%d) or the sysfs-support of your device's driver needs to be fixed, "
 440                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 441                      UDEV_VERSION, devpath, rc);
 442
 443         return rc;
 444 }