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 "logging.h"
  32 #include "udev_version.h"
  33 #include "udev_sysfs.h"
  34 #include "libsysfs/sysfs/libsysfs.h"
  35
  36 /* list of subsystem specific files
  37  * NULL if there is no file to wait for
  38  */
  39 static struct subsystem_file {
  40         char *subsystem;
  41         char *file;
  42 } subsystem_files[] = {
  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         { NULL, NULL }
  56 };
  57
  58 int subsystem_expect_no_dev(const char *subsystem)
  59 {
  60         struct subsystem_file *file;
  61
  62         for (file = subsystem_files; file->subsystem != NULL; file++)
  63                 if (strcmp(subsystem, file->subsystem) == 0)
  64                         return 1;
  65
  66         return 0;
  67 }
  68
  69 /* get subsystem specific files, returns "dev" if no other found */
  70 static char *get_subsystem_specific_file(const char *subsystem)
  71 {
  72         struct subsystem_file *file;
  73
  74         /* look if we want to look for another file instead of "dev" */
  75         for (file = subsystem_files; file->subsystem != NULL; file++)
  76                 if (strcmp(subsystem, file->subsystem) == 0)
  77                         return file->file;
  78
  79         return "dev";
  80 }
  81
  82 /* wait for class pecific file to show up */
  83 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev,
  84                                             const char **error)
  85 {
  86         const char *file;
  87         char filename[SYSFS_PATH_MAX];
  88         int loop;
  89
  90         file = get_subsystem_specific_file(class_dev->classname);
  91         if (file == NULL) {
  92                 dbg("class '%s' has no file to wait for", class_dev->classname);
  93                 return 0;
  94         }
  95
  96         snprintf(filename, SYSFS_PATH_MAX-1, "%s/%s", class_dev->path, file);
  97         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, filename);
  98
  99         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 100         while (--loop) {
 101                 struct stat stats;
 102
 103                 if (stat(class_dev->path, &stats) == -1) {
 104                         dbg("'%s' now disappeared (probably remove has beaten us)", class_dev->path);
 105                         return -ENODEV;
 106                 }
 107
 108                 if (stat(filename, &stats) == 0) {
 109                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
 110                         return 0;
 111                 }
 112
 113                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 114         }
 115
 116         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 117         if (error)
 118                 *error = "class specific file unavailable";
 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 = "block",         .device = "dm-" },
 149                 { .subsystem = "input",         .device = "event" },
 150                 { .subsystem = "input",         .device = "mice" },
 151                 { .subsystem = "input",         .device = "mouse" },
 152                 { .subsystem = "input",         .device = "ts" },
 153                 { .subsystem = "vc",            .device = NULL },
 154                 { .subsystem = "tty",           .device = NULL },
 155                 { .subsystem = "cpuid",         .device = "cpu" },
 156                 { .subsystem = "graphics",      .device = "fb" },
 157                 { .subsystem = "mem",           .device = NULL },
 158                 { .subsystem = "misc",          .device = NULL },
 159                 { .subsystem = "msr",           .device = NULL },
 160                 { .subsystem = "netlink",       .device = NULL },
 161                 { .subsystem = "net",           .device = "sit" },
 162                 { .subsystem = "net",           .device = "lo" },
 163                 { .subsystem = "net",           .device = "tap" },
 164                 { .subsystem = "net",           .device = "ipsec" },
 165                 { .subsystem = "net",           .device = "dummy" },
 166                 { .subsystem = "net",           .device = "irda" },
 167                 { .subsystem = "net",           .device = "ppp" },
 168                 { .subsystem = "net",           .device = "tun" },
 169                 { .subsystem = "net",           .device = "pan" },
 170                 { .subsystem = "net",           .device = "bnep" },
 171                 { .subsystem = "net",           .device = "vmnet" },
 172                 { .subsystem = "ppp",           .device = NULL },
 173                 { .subsystem = "sound",         .device = NULL },
 174                 { .subsystem = "printer",       .device = "lp" },
 175                 { .subsystem = "nvidia",        .device = NULL },
 176                 { .subsystem = "video4linux",   .device = "vbi" },
 177                 { .subsystem = "dvb",           .device = NULL },
 178                 { .subsystem = "lirc",          .device = NULL },
 179                 { .subsystem = "firmware",      .device = NULL },
 180                 { .subsystem = "drm",           .device = NULL },
 181                 { .subsystem = "pci_bus",       .device = NULL },
 182                 { .subsystem = "ieee1394",      .device = NULL },
 183                 { .subsystem = "ieee1394_host", .device = NULL },
 184                 { .subsystem = "ieee1394_node", .device = NULL },
 185                 { .subsystem = "raw",           .device = NULL },
 186                 { .subsystem = "zaptel",        .device = NULL },
 187                 { .subsystem = "tiglusb",       .device = NULL },
 188                 { .subsystem = "ppdev",         .device = NULL },
 189                 { .subsystem = "ticables",      .device = NULL },
 190                 { .subsystem = "snsc",          .device = NULL },
 191                 { .subsystem = "staliomem",     .device = NULL },
 192                 { .subsystem = "tape",          .device = NULL },
 193                 { .subsystem = "ip2",           .device = NULL },
 194                 { .subsystem = "tpqic02",       .device = NULL },
 195                 { .subsystem = "dsp56k",        .device = NULL },
 196                 { .subsystem = "zft",           .device = NULL },
 197                 { .subsystem = "adb",           .device = NULL },
 198                 { .subsystem = "cosa",          .device = NULL },
 199                 { .subsystem = "pg",            .device = NULL },
 200                 { .subsystem = "pt",            .device = NULL },
 201                 { .subsystem = "capi",          .device = NULL },
 202                 { NULL, NULL }
 203         };
 204         struct class_device *classdevice;
 205         int len;
 206
 207         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 208                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 209                         /* see if no device in this class is expected to have a device-link */
 210                         if (classdevice->device == NULL)
 211                                 return 1;
 212
 213                         len = strlen(classdevice->device);
 214
 215                         /* see if device name matches */
 216                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 217                                 continue;
 218
 219                         /* exact name match */
 220                         if (strlen(class_dev->name) == len)
 221                                 return 1;
 222
 223                         /* name match with instance number */
 224                         if (isdigit(class_dev->name[len]))
 225                                 return 1;
 226                 }
 227         }
 228
 229         return 0;
 230 }
 231
 232 /* skip waiting for the bus */
 233 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 234 {
 235         static char *devices_without_bus[] = {
 236                 "scsi_host",
 237                 "i2c-adapter",
 238                 NULL
 239         };
 240         char **device;
 241
 242         for (device = devices_without_bus; *device != NULL; device++) {
 243                 int len = strlen(*device);
 244
 245                 if (strncmp(class_dev->classname, *device, len) == 0)
 246                         return 1;
 247         }
 248
 249         return 0;
 250 }
 251
 252 /* wait for the bus and for a bus specific file to show up */
 253 int wait_for_bus_device(struct sysfs_device *devices_dev,
 254                         const char **error)
 255 {
 256         static struct bus_file {
 257                 char *bus;
 258                 char *file;
 259         } bus_files[] = {
 260                 { .bus = "scsi",        .file = "vendor" },
 261                 { .bus = "usb",         .file = "idVendor" },
 262                 { .bus = "usb",         .file = "iInterface" },
 263                 { .bus = "usb",         .file = "bNumEndpoints" },
 264                 { .bus = "usb-serial",  .file = "detach_state" },
 265                 { .bus = "ide",         .file = "detach_state" },
 266                 { .bus = "pci",         .file = "vendor" },
 267                 { .bus = "platform",    .file = "detach_state" },
 268                 { .bus = "i2c",         .file = "detach_state" },
 269                 { .bus = "ieee1394",    .file = "node_count" },
 270                 { .bus = "ieee1394",    .file = "nodeid" },
 271                 { .bus = "ieee1394",    .file = "address" },
 272                 { NULL, NULL }
 273         };
 274         struct bus_file *busfile;
 275         int loop;
 276
 277         /* wait for the bus device link to the devices device */
 278         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 279         while (--loop) {
 280                 if (sysfs_get_device_bus(devices_dev) == 0)
 281                         break;
 282
 283                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 284         }
 285         if (loop == 0) {
 286                 dbg("error: getting bus device link");
 287                 if (error)
 288                         *error = "no bus device link";
 289                 return -1;
 290         }
 291         dbg("bus device link found for bus '%s'", devices_dev->bus);
 292
 293         /* wait for a bus specific file to show up */
 294         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 295         while (--loop) {
 296                 int found_bus_type = 0;
 297
 298                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 299                         if (strcmp(devices_dev->bus, busfile->bus) == 0) {
 300                                 char filename[SYSFS_PATH_MAX];
 301                                 struct stat stats;
 302
 303                                 found_bus_type = 1;
 304                                 snprintf(filename, SYSFS_PATH_MAX-1, "%s/%s", devices_dev->path, busfile->file);
 305                                 dbg("looking at bus '%s' for specific file '%s'", devices_dev->bus, filename);
 306
 307                                 if (stat(filename, &stats) == 0) {
 308                                         dbg("bus '%s' specific file '%s' found", devices_dev->bus, busfile->file);
 309                                         return 0;
 310                                 }
 311                         }
 312                 }
 313                 if (found_bus_type == 0) {
 314                         if (error)
 315                                 *error = "unknown bus";
 316                         info("error: unknown bus, please report to "
 317                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
 318                         return -1;
 319                 }
 320                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 321         }
 322
 323         dbg("error: getting bus '%s' specific file '%s'", devices_dev->bus, busfile->file);
 324         if (error)
 325                 *error = "bus specific file unavailable";
 326         return -1;
 327 }
 328
 329
 330 struct sysfs_class_device *open_class_device_wait(const char *path)
 331 {
 332         struct sysfs_class_device *class_dev;
 333         int loop;
 334
 335         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 336         while (--loop) {
 337                 class_dev = sysfs_open_class_device_path(path);
 338                 if (class_dev)
 339                         break;
 340
 341                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 342         }
 343
 344         return (class_dev);
 345 }
 346
 347 int wait_for_class_device(struct sysfs_class_device *class_dev,
 348                           const char **error)
 349 {
 350         struct sysfs_class_device *class_dev_parent;
 351         struct sysfs_device *devices_dev = NULL;
 352         int loop;
 353
 354         if (wait_for_class_device_attributes(class_dev, error) != 0)
 355                 return -ENOENT;
 356
 357         /* skip devices without devices-link */
 358         if (class_device_expect_no_device_link(class_dev)) {
 359                 dbg("no device symlink expected for '%s', ", class_dev->name);
 360                 return -ENODEV;
 361         }
 362
 363         /* the symlink may be on the parent device */
 364         class_dev_parent = sysfs_get_classdev_parent(class_dev);
 365         if (class_dev_parent)
 366                 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 367
 368         /* wait for the symlink to the devices device */
 369         dbg("waiting for symlink to devices device");
 370         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 371         while (--loop) {
 372                 if (class_dev_parent)
 373                         devices_dev = sysfs_get_classdev_device(class_dev_parent);
 374                 else
 375                         devices_dev = sysfs_get_classdev_device(class_dev);
 376
 377                 if (devices_dev)
 378                         break;
 379
 380                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 381         }
 382         if (!devices_dev) {
 383                 dbg(" error: no devices device symlink found");
 384                 if (error)
 385                         *error = "no device symlink";
 386                 return -ENODEV;
 387         }
 388         dbg("device symlink found pointing to '%s'", devices_dev->path);
 389
 390         /* wait for the bus value */
 391         if (class_device_expect_no_bus(class_dev)) {
 392                 dbg("no bus device expected for '%s', ", class_dev->classname);
 393                 return 0;
 394         } else {
 395                 return wait_for_bus_device(devices_dev, error);
 396         }
 397 }
 398
 399 struct sysfs_device *open_devices_device_wait(const char *path)
 400 {
 401         struct sysfs_device *devices_dev;
 402         int loop;
 403
 404         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 405         while (--loop) {
 406                 devices_dev = sysfs_open_device_path(path);
 407                 if (devices_dev)
 408                         break;
 409
 410                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 411         }
 412
 413         return(devices_dev);
 414 }