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 = "lirc",          .device = NULL },
 178                 { .subsystem = "firmware",      .device = NULL },
 179                 { .subsystem = "drm",           .device = NULL },
 180                 { .subsystem = "pci_bus",       .device = NULL },
 181                 { .subsystem = "ieee1394",      .device = NULL },
 182                 { .subsystem = "ieee1394_host", .device = NULL },
 183                 { .subsystem = "ieee1394_node", .device = NULL },
 184                 { .subsystem = "raw",           .device = NULL },
 185                 { .subsystem = "zaptel",        .device = NULL },
 186                 { NULL, NULL }
 187         };
 188         struct class_device *classdevice;
 189         int len;
 190
 191         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 192                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 193                         /* see if no device in this class is expected to have a device-link */
 194                         if (classdevice->device == NULL)
 195                                 return 1;
 196
 197                         len = strlen(classdevice->device);
 198
 199                         /* see if device name matches */
 200                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 201                                 continue;
 202
 203                         /* exact name match */
 204                         if (strlen(class_dev->name) == len)
 205                                 return 1;
 206
 207                         /* name match with instance number */
 208                         if (isdigit(class_dev->name[len]))
 209                                 return 1;
 210                 }
 211         }
 212
 213         return 0;
 214 }
 215
 216 /* skip waiting for the bus */
 217 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 218 {
 219         static char *devices_without_bus[] = {
 220                 "scsi_host",
 221                 "i2c-adapter",
 222                 NULL
 223         };
 224         char **device;
 225
 226         for (device = devices_without_bus; *device != NULL; device++) {
 227                 int len = strlen(*device);
 228
 229                 if (strncmp(class_dev->classname, *device, len) == 0)
 230                         return 1;
 231         }
 232
 233         return 0;
 234 }
 235
 236 /* wait for the bus and for a bus specific file to show up */
 237 int wait_for_bus_device(struct sysfs_device *devices_dev,
 238                         const char **error)
 239 {
 240         static struct bus_file {
 241                 char *bus;
 242                 char *file;
 243         } bus_files[] = {
 244                 { .bus = "scsi",        .file = "vendor" },
 245                 { .bus = "usb",         .file = "idVendor" },
 246                 { .bus = "usb",         .file = "iInterface" },
 247                 { .bus = "usb",         .file = "bNumEndpoints" },
 248                 { .bus = "usb-serial",  .file = "detach_state" },
 249                 { .bus = "ide",         .file = "detach_state" },
 250                 { .bus = "pci",         .file = "vendor" },
 251                 { .bus = "platform",    .file = "detach_state" },
 252                 { .bus = "i2c",         .file = "detach_state" },
 253                 { .bus = "ieee1394",    .file = "node_count" },
 254                 { .bus = "ieee1394",    .file = "nodeid" },
 255                 { .bus = "ieee1394",    .file = "address" },
 256                 { NULL, NULL }
 257         };
 258         struct bus_file *busfile;
 259         int loop;
 260
 261         /* wait for the bus device link to the devices device */
 262         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 263         while (--loop) {
 264                 if (sysfs_get_device_bus(devices_dev) == 0)
 265                         break;
 266
 267                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 268         }
 269         if (loop == 0) {
 270                 dbg("error: getting bus device link");
 271                 if (error)
 272                         *error = "no bus device link";
 273                 return -1;
 274         }
 275         dbg("bus device link found for bus '%s'", devices_dev->bus);
 276
 277         /* wait for a bus specific file to show up */
 278         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 279         while (--loop) {
 280                 int found_bus_type = 0;
 281
 282                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 283                         if (strcmp(devices_dev->bus, busfile->bus) == 0) {
 284                                 char filename[SYSFS_PATH_MAX];
 285                                 struct stat stats;
 286
 287                                 found_bus_type = 1;
 288                                 snprintf(filename, SYSFS_PATH_MAX-1, "%s/%s", devices_dev->path, busfile->file);
 289                                 dbg("looking at bus '%s' for specific file '%s'", devices_dev->bus, filename);
 290
 291                                 if (stat(filename, &stats) == 0) {
 292                                         dbg("bus '%s' specific file '%s' found", devices_dev->bus, busfile->file);
 293                                         return 0;
 294                                 }
 295                         }
 296                 }
 297                 if (found_bus_type == 0) {
 298                         if (error)
 299                                 *error = "unknown bus";
 300                         info("error: unknown bus, please report to "
 301                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
 302                         return -1;
 303                 }
 304                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 305         }
 306
 307         dbg("error: getting bus '%s' specific file '%s'", devices_dev->bus, busfile->file);
 308         if (error)
 309                 *error = "bus specific file unavailable";
 310         return -1;
 311 }
 312
 313
 314 struct sysfs_class_device *open_class_device_wait(const char *path)
 315 {
 316         struct sysfs_class_device *class_dev;
 317         int loop;
 318
 319         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 320         while (--loop) {
 321                 class_dev = sysfs_open_class_device_path(path);
 322                 if (class_dev)
 323                         break;
 324
 325                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 326         }
 327
 328         return (class_dev);
 329 }
 330
 331 int wait_for_class_device(struct sysfs_class_device *class_dev,
 332                           const char **error)
 333 {
 334         struct sysfs_class_device *class_dev_parent;
 335         struct sysfs_device *devices_dev = NULL;
 336         int loop;
 337
 338         if (wait_for_class_device_attributes(class_dev, error) != 0)
 339                 return -ENOENT;
 340
 341         /* skip devices without devices-link */
 342         if (class_device_expect_no_device_link(class_dev)) {
 343                 dbg("no device symlink expected for '%s', ", class_dev->name);
 344                 return -ENODEV;
 345         }
 346
 347         /* the symlink may be on the parent device */
 348         class_dev_parent = sysfs_get_classdev_parent(class_dev);
 349         if (class_dev_parent)
 350                 dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 351
 352         /* wait for the symlink to the devices device */
 353         dbg("waiting for symlink to devices device");
 354         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 355         while (--loop) {
 356                 if (class_dev_parent)
 357                         devices_dev = sysfs_get_classdev_device(class_dev_parent);
 358                 else
 359                         devices_dev = sysfs_get_classdev_device(class_dev);
 360
 361                 if (devices_dev)
 362                         break;
 363
 364                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 365         }
 366         if (!devices_dev) {
 367                 dbg(" error: no devices device symlink found");
 368                 if (error)
 369                         *error = "no device symlink";
 370                 return -ENODEV;
 371         }
 372         dbg("device symlink found pointing to '%s'", devices_dev->path);
 373
 374         /* wait for the bus value */
 375         if (class_device_expect_no_bus(class_dev)) {
 376                 dbg("no bus device expected for '%s', ", class_dev->classname);
 377                 return 0;
 378         } else {
 379                 return wait_for_bus_device(devices_dev, error);
 380         }
 381 }
 382
 383 struct sysfs_device *open_devices_device_wait(const char *path)
 384 {
 385         struct sysfs_device *devices_dev;
 386         int loop;
 387
 388         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 389         while (--loop) {
 390                 devices_dev = sysfs_open_device_path(path);
 391                 if (devices_dev)
 392                         break;
 393
 394                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 395         }
 396
 397         return(devices_dev);
 398 }