udev_sysfs.c

   1 /*
   2  * udev_sysfs.c  - sysfs linux kernel specific knowledge
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   6  *
   7  *      This program is free software; you can redistribute it and/or modify it
   8  *      under the terms of the GNU General Public License as published by the
   9  *      Free Software Foundation version 2 of the License.
  10  *
  11  *      This program is distributed in the hope that it will be useful, but
  12  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *      General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU General Public License along
  17  *      with this program; if not, write to the Free Software Foundation, Inc.,
  18  *      675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #include <stdio.h>
  23 #include <stddef.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <errno.h>
  29 #include <sys/stat.h>
  30
  31 #include "libsysfs/sysfs/libsysfs.h"
  32 #include "udev_version.h"
  33 #include "udev_sysfs.h"
  34 #include "udev_utils.h"
  35 #include "logging.h"
  36
  37 /* list of subsystem specific files, NULL if there is no file to wait for */
  38 static const struct subsystem_file {
  39         const char *subsystem;
  40         const char *file;
  41 } subsystem_files[] = {
  42         { .subsystem = "class",         .file = NULL },
  43         { .subsystem = "net",           .file = "ifindex" },
  44         { .subsystem = "scsi_host",     .file = "unique_id" },
  45         { .subsystem = "scsi_device",   .file = NULL },
  46         { .subsystem = "pcmcia_socket", .file = "card_type" },
  47         { .subsystem = "usb_host",      .file = NULL },
  48         { .subsystem = "bluetooth",     .file = "address" },
  49         { .subsystem = "firmware",      .file = "data" },
  50         { .subsystem = "i2c-adapter",   .file = NULL },
  51         { .subsystem = "pci_bus",       .file = NULL },
  52         { .subsystem = "ieee1394",      .file = NULL },
  53         { .subsystem = "ieee1394_host", .file = NULL },
  54         { .subsystem = "ieee1394_node", .file = NULL },
  55         { .subsystem = "fc_transport",  .file = "port_id" },
  56         { .subsystem = "fc_host",       .file = "port_id" },
  57         { .subsystem = "spi_transport", .file = "width" },
  58         { .subsystem = "spi_host",      .file = "width" },
  59         { NULL, NULL }
  60 };
  61
  62 int subsystem_expect_no_dev(const char *subsystem)
  63 {
  64         const struct subsystem_file *file;
  65
  66         for (file = subsystem_files; file->subsystem != NULL; file++)
  67                 if (strcmp(subsystem, file->subsystem) == 0)
  68                         return 1;
  69
  70         return 0;
  71 }
  72
  73 /* get subsystem specific files, returns "dev" if no other found */
  74 static const char *get_subsystem_specific_file(const char *subsystem)
  75 {
  76         const struct subsystem_file *file;
  77
  78         /* look if we want to look for another file instead of "dev" */
  79         for (file = subsystem_files; file->subsystem != NULL; file++)
  80                 if (strcmp(subsystem, file->subsystem) == 0)
  81                         return file->file;
  82
  83         return "dev";
  84 }
  85
  86 /* wait for class pecific file to show up */
  87 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev,
  88                                             const char **error)
  89 {
  90         const char *file;
  91         char filename[SYSFS_PATH_MAX];
  92         int loop;
  93
  94         file = get_subsystem_specific_file(class_dev->classname);
  95         if (file == NULL) {
  96                 dbg("class '%s' has no file to wait for", class_dev->classname);
  97                 return 0;
  98         }
  99
 100         snprintf(filename, SYSFS_PATH_MAX-1, "%s/%s", class_dev->path, file);
 101         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, filename);
 102
 103         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 104         while (--loop) {
 105                 struct stat stats;
 106
 107                 if (stat(class_dev->path, &stats) == -1) {
 108                         dbg("'%s' now disappeared (probably remove has beaten us)", class_dev->path);
 109                         return -ENODEV;
 110                 }
 111
 112                 if (stat(filename, &stats) == 0) {
 113                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
 114                         return 0;
 115                 }
 116
 117                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 118         }
 119
 120         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 121         if (error)
 122                 *error = "class specific file unavailable";
 123         return -ENOENT;
 124 }
 125
 126 /* check if we need to wait for a physical device */
 127 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 128 {
 129         /* list of devices without a "device" symlink to the physical device
 130          * if device is set to NULL, no devices in that subsystem has a link */
 131         static const struct class_device {
 132                 const char *subsystem;
 133                 const char *device;
 134         } class_device[] = {
 135                 { .subsystem = "block",         .device = "double" },
 136                 { .subsystem = "block",         .device = "nb" },
 137                 { .subsystem = "block",         .device = "ram" },
 138                 { .subsystem = "block",         .device = "loop" },
 139                 { .subsystem = "block",         .device = "fd" },
 140                 { .subsystem = "block",         .device = "md" },
 141                 { .subsystem = "block",         .device = "dos_cd" },
 142                 { .subsystem = "block",         .device = "rflash" },
 143                 { .subsystem = "block",         .device = "rom" },
 144                 { .subsystem = "block",         .device = "rrom" },
 145                 { .subsystem = "block",         .device = "flash" },
 146                 { .subsystem = "block",         .device = "msd" },
 147                 { .subsystem = "block",         .device = "sbpcd" },
 148                 { .subsystem = "block",         .device = "pcd" },
 149                 { .subsystem = "block",         .device = "pf" },
 150                 { .subsystem = "block",         .device = "scd" },
 151                 { .subsystem = "block",         .device = "ubd" },
 152                 { .subsystem = "block",         .device = "dm-" },
 153                 { .subsystem = "block",         .device = "bcrypt" },
 154                 { .subsystem = "input",         .device = "event" },
 155                 { .subsystem = "input",         .device = "mice" },
 156                 { .subsystem = "input",         .device = "mouse" },
 157                 { .subsystem = "input",         .device = "ts" },
 158                 { .subsystem = "vc",            .device = NULL },
 159                 { .subsystem = "tty",           .device = NULL },
 160                 { .subsystem = "cpuid",         .device = "cpu" },
 161                 { .subsystem = "graphics",      .device = "fb" },
 162                 { .subsystem = "mem",           .device = NULL },
 163                 { .subsystem = "misc",          .device = NULL },
 164                 { .subsystem = "msr",           .device = NULL },
 165                 { .subsystem = "netlink",       .device = NULL },
 166                 { .subsystem = "net",           .device = "sit" },
 167                 { .subsystem = "net",           .device = "lo" },
 168                 { .subsystem = "net",           .device = "tap" },
 169                 { .subsystem = "net",           .device = "ipsec" },
 170                 { .subsystem = "net",           .device = "dummy" },
 171                 { .subsystem = "net",           .device = "irda" },
 172                 { .subsystem = "net",           .device = "ppp" },
 173                 { .subsystem = "net",           .device = "tun" },
 174                 { .subsystem = "net",           .device = "pan" },
 175                 { .subsystem = "net",           .device = "bnep" },
 176                 { .subsystem = "net",           .device = "vmnet" },
 177                 { .subsystem = "net",           .device = "ippp" },
 178                 { .subsystem = "net",           .device = "nlv" },
 179                 { .subsystem = "net",           .device = "atml" },
 180                 { .subsystem = "ppp",           .device = NULL },
 181                 { .subsystem = "sound",         .device = NULL },
 182                 { .subsystem = "printer",       .device = "lp" },
 183                 { .subsystem = "ppdev",         .device = NULL },
 184                 { .subsystem = "nvidia",        .device = NULL },
 185                 { .subsystem = "video4linux",   .device = "vbi" },
 186                 { .subsystem = "dvb",           .device = NULL },
 187                 { .subsystem = "lirc",          .device = NULL },
 188                 { .subsystem = "firmware",      .device = NULL },
 189                 { .subsystem = "drm",           .device = NULL },
 190                 { .subsystem = "pci_bus",       .device = NULL },
 191                 { .subsystem = "ieee1394",      .device = NULL },
 192                 { .subsystem = "ieee1394_host", .device = NULL },
 193                 { .subsystem = "ieee1394_node", .device = NULL },
 194                 { .subsystem = "raw",           .device = NULL },
 195                 { .subsystem = "zaptel",        .device = NULL },
 196                 { .subsystem = "tiglusb",       .device = NULL },
 197                 { .subsystem = "ppdev",         .device = NULL },
 198                 { .subsystem = "ticables",      .device = NULL },
 199                 { .subsystem = "snsc",          .device = NULL },
 200                 { .subsystem = "staliomem",     .device = NULL },
 201                 { .subsystem = "tape",          .device = NULL },
 202                 { .subsystem = "ip2",           .device = NULL },
 203                 { .subsystem = "tpqic02",       .device = NULL },
 204                 { .subsystem = "dsp56k",        .device = NULL },
 205                 { .subsystem = "zft",           .device = NULL },
 206                 { .subsystem = "adb",           .device = NULL },
 207                 { .subsystem = "cosa",          .device = NULL },
 208                 { .subsystem = "pg",            .device = NULL },
 209                 { .subsystem = "pt",            .device = NULL },
 210                 { .subsystem = "capi",          .device = NULL },
 211                 { NULL, NULL }
 212         };
 213         const struct class_device *classdevice;
 214         int len;
 215
 216         /* the kernel may tell us what to wait for */
 217         if (kernel_release_satisfactory(2,6,10) > 0)
 218                 if (getenv("PHYSDEVPATH") == NULL) {
 219                         dbg("the kernel says, that there is no physical device for '%s'", class_dev->path);
 220                         return 1;
 221                 }
 222
 223         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 224                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 225                         /* see if no device in this class is expected to have a device-link */
 226                         if (classdevice->device == NULL)
 227                                 return 1;
 228
 229                         len = strlen(classdevice->device);
 230
 231                         /* see if device name matches */
 232                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 233                                 continue;
 234
 235                         /* exact name match */
 236                         if (strlen(class_dev->name) == len)
 237                                 return 1;
 238
 239                         /* name match with instance number */
 240                         if (isdigit(class_dev->name[len]))
 241                                 return 1;
 242                 }
 243         }
 244
 245         return 0;
 246 }
 247
 248 /* skip waiting for the bus of the devices device */
 249 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 250 {
 251         static const char *devices_without_bus[] = {
 252                 "scsi_host",
 253                 "i2c-adapter",
 254                 "i2c-dev",
 255                 NULL
 256         };
 257         const char **device;
 258
 259         for (device = devices_without_bus; *device != NULL; device++) {
 260                 int len = strlen(*device);
 261
 262                 if (strncmp(class_dev->classname, *device, len) == 0)
 263                         return 1;
 264         }
 265
 266         return 0;
 267 }
 268
 269 /* wait for a devices device specific file to show up */
 270 int wait_for_devices_device(struct sysfs_device *devices_dev,
 271                         const char **error)
 272 {
 273         static const struct device_file {
 274                 const char *bus;
 275                 const char *file;
 276         } device_files[] = {
 277                 { .bus = "scsi",        .file = "vendor" },
 278                 { .bus = "usb",         .file = "idVendor" },
 279                 { .bus = "usb",         .file = "iInterface" },
 280                 { .bus = "usb",         .file = "bNumEndpoints" },
 281                 { .bus = "usb-serial",  .file = "detach_state" },
 282                 { .bus = "ide",         .file = "detach_state" },
 283                 { .bus = "pci",         .file = "vendor" },
 284                 { .bus = "platform",    .file = "detach_state" },
 285                 { .bus = "pcmcia",      .file = "detach_state" },
 286                 { .bus = "i2c",         .file = "detach_state" },
 287                 { .bus = "ieee1394",    .file = "node_count" },
 288                 { .bus = "ieee1394",    .file = "nodeid" },
 289                 { .bus = "ieee1394",    .file = "address" },
 290                 { .bus = "bttv-sub",    .file = NULL },
 291                 { .bus = "pnp",         .file = "detach_state" },
 292                 { .bus = "eisa",        .file = "detach_state" },
 293                 { .bus = "pseudo",      .file = "detach_state" },
 294                 { .bus = "mmc",         .file = "detach_state" },
 295                 { .bus = "macio",       .file = "detach_state" },
 296                 { .bus = "of_platform", .file = "detach_state" },
 297                 { .bus = "vio",         .file = "detach_state" },
 298                 { .bus = "ecard",       .file = "detach_state" },
 299                 { .bus = "sa1111-rab",  .file = "detach_state" },
 300                 { .bus = "amba",        .file = "detach_state" },
 301                 { .bus = "locomo-bus",  .file = "detach_state" },
 302                 { .bus = "logicmodule", .file = "detach_state" },
 303                 { .bus = "parisc",      .file = "detach_state" },
 304                 { .bus = "ocp",         .file = "detach_state" },
 305                 { .bus = "dio",         .file = "detach_state" },
 306                 { .bus = "MCA",         .file = "detach_state" },
 307                 { .bus = "wl",          .file = "detach_state" },
 308                 { .bus = "ccwgroup",    .file = "detach_state" },
 309                 { .bus = "css",         .file = "detach_state" },
 310                 { .bus = "ccw",         .file = "detach_state" },
 311                 { .bus = "iucv",        .file = "detach_state" },
 312                 { NULL, NULL }
 313         };
 314         const struct device_file *devicefile;
 315         int loop;
 316
 317         /* the kernel may tell us what to wait for */
 318         if (kernel_release_satisfactory(2,6,10) > 0)
 319                 if (getenv("PHYSDEVBUS") == NULL) {
 320                         dbg("the kernel says, that there is no bus for '%s'", devices_dev->path);
 321                         return 0;
 322                 }
 323
 324         /* wait for the bus device link to the devices device */
 325         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 326         while (--loop) {
 327                 if (sysfs_get_device_bus(devices_dev) == 0)
 328                         break;
 329
 330                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 331         }
 332         if (loop == 0) {
 333                 dbg("error: getting bus device link");
 334                 if (error)
 335                         *error = "no bus device link";
 336                 return -1;
 337         }
 338         dbg("bus device link found for bus '%s'", devices_dev->bus);
 339
 340         /* wait for a bus device specific file to show up */
 341         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 342         while (--loop) {
 343                 int found_bus_type = 0;
 344
 345                 for (devicefile = device_files; devicefile->bus != NULL; devicefile++) {
 346                         if (strcmp(devices_dev->bus, devicefile->bus) == 0) {
 347                                 char filename[SYSFS_PATH_MAX];
 348                                 struct stat stats;
 349
 350                                 if (devicefile->file == NULL) {
 351                                         dbg("bus '%s' has no file to wait for", devices_dev->bus);
 352                                         return 0;
 353                                 }
 354
 355                                 found_bus_type = 1;
 356                                 snprintf(filename, SYSFS_PATH_MAX-1, "%s/%s", devices_dev->path, devicefile->file);
 357                                 dbg("looking at bus '%s' device for specific file '%s'", devices_dev->bus, filename);
 358
 359                                 if (stat(filename, &stats) == 0) {
 360                                         dbg("bus '%s' device specific file '%s' found", devices_dev->bus, devicefile->file);
 361                                         return 0;
 362                                 }
 363                         }
 364                 }
 365                 if (found_bus_type == 0) {
 366                         if (error)
 367                                 *error = "unknown bus";
 368                         info("error: unknown bus, please report to "
 369                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
 370                         return -1;
 371                 }
 372                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 373         }
 374
 375         dbg("error: getting '%s' device specific file '%s'", devices_dev->bus, devicefile->file);
 376         if (error)
 377                 *error = "bus device specific file unavailable";
 378         return -1;
 379 }
 380
 381
 382 struct sysfs_class_device *wait_class_device_open(const char *path)
 383 {
 384         struct sysfs_class_device *class_dev = NULL;
 385         int loop;
 386
 387         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 388         while (--loop) {
 389                 class_dev = sysfs_open_class_device_path(path);
 390                 if (class_dev)
 391                         break;
 392
 393                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 394         }
 395
 396         return class_dev;
 397 }
 398
 399 int wait_for_class_device(struct sysfs_class_device *class_dev,
 400                           const char **error)
 401 {
 402         struct sysfs_class_device *class_dev_parent;
 403         struct sysfs_device *devices_dev = NULL;
 404         int loop;
 405
 406         if (wait_for_class_device_attributes(class_dev, error) != 0)
 407                 return -ENOENT;
 408
 409         /* skip devices without devices-link */
 410         if (class_device_expect_no_device_link(class_dev)) {
 411                 dbg("no device symlink expected for '%s', ", class_dev->name);
 412                 return 0;
 413         }
 414
 415         /* the symlink may be on the parent device */
 416         class_dev_parent = sysfs_get_classdev_parent(class_dev);
 417         if (class_dev_parent)
 418                 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 419
 420         /* wait for the symlink to the devices device */
 421         dbg("waiting for symlink to devices device");
 422         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 423         while (--loop) {
 424                 if (class_dev_parent)
 425                         devices_dev = sysfs_get_classdev_device(class_dev_parent);
 426                 else
 427                         devices_dev = sysfs_get_classdev_device(class_dev);
 428
 429                 if (devices_dev)
 430                         break;
 431
 432                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 433         }
 434         if (!devices_dev) {
 435                 dbg(" error: no devices device symlink found");
 436                 if (error)
 437                         *error = "no device symlink";
 438                 return -ENODEV;
 439         }
 440         dbg("device symlink found pointing to '%s'", devices_dev->path);
 441
 442         /* wait for the devices device */
 443         if (class_device_expect_no_bus(class_dev)) {
 444                 dbg("no bus device expected for '%s', ", class_dev->classname);
 445                 return 0;
 446         }
 447
 448         return wait_for_devices_device(devices_dev, error);
 449 }
 450
 451 struct sysfs_device *wait_devices_device_open(const char *path)
 452 {
 453         struct sysfs_device *devices_dev = NULL;
 454         int loop;
 455
 456         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 457         while (--loop) {
 458                 devices_dev = sysfs_open_device_path(path);
 459                 if (devices_dev)
 460                         break;
 461
 462                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 463         }
 464
 465         return devices_dev;
 466 }