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  *
  10  *      This program is free software; you can redistribute it and/or modify it
  11  *      under the terms of the GNU General Public License as published by the
  12  *      Free Software Foundation version 2 of the License.
  13  *
  14  *      This program is distributed in the hope that it will be useful, but
  15  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *      General Public License for more details.
  18  *
  19  *      You should have received a copy of the GNU General Public License along
  20  *      with this program; if not, write to the Free Software Foundation, Inc.,
  21  *      675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  */
  24
  25 #include <stdio.h>
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <errno.h>
  32 #include <sys/stat.h>
  33
  34 #include "logging.h"
  35 #include "udev_version.h"
  36 #include "libsysfs/sysfs/libsysfs.h"
  37
  38 #ifdef LOG
  39 unsigned char logname[LOGNAME_SIZE];
  40 void log_message(int level, const char *format, ...)
  41 {
  42         va_list args;
  43
  44         va_start(args, format);
  45         vsyslog(level, format, args);
  46         va_end(args);
  47 }
  48 #endif
  49
  50 #define WAIT_MAX_SECONDS                10
  51 #define WAIT_LOOP_PER_SECOND            20
  52
  53 /* wait for specific file to show up, normally the "dev"-file */
  54 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
  55 {
  56         static struct class_file {
  57                 char *subsystem;
  58                 char *file;
  59         } class_files[] = {
  60                 { .subsystem = "net",           .file = "ifindex" },
  61                 { .subsystem = "scsi_host",     .file = "unique_id" },
  62                 { .subsystem = "scsi_device",   .file = NULL },
  63                 { .subsystem = "pcmcia_socket", .file = NULL }, /* all files are unreadable in empty slot :( */
  64                 { .subsystem = "usb_host",      .file = NULL },
  65                 { .subsystem = "bluetooth",     .file = "address" },
  66                 { .subsystem = "firmware",      .file = "data" },
  67                 { .subsystem = "i2c-adapter",   .file = NULL },
  68                 { .subsystem = "pci_bus",       .file = NULL },
  69                 { .subsystem = "ieee1394",      .file = NULL },
  70                 { .subsystem = "ieee1394_host", .file = NULL },
  71                 { .subsystem = "ieee1394_node", .file = NULL },
  72                 { NULL, NULL }
  73         };
  74         struct class_file *classfile;
  75         const char *file = "dev";
  76         int loop;
  77
  78         /* look if we want to look for another file instead of "dev" */
  79         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  80                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  81                         if (classfile->file == NULL) {
  82                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  83                                 return 0;
  84                         }
  85                         file = classfile->file;
  86                         break;
  87                 }
  88         }
  89         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
  90
  91         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
  92         while (--loop) {
  93                 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
  94                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
  95                         return 0;
  96                 }
  97
  98                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
  99         }
 100
 101         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 102         return -1;
 103 }
 104
 105 /* check if we need to wait for a physical device */
 106 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 107 {
 108         /* list of devices without a "device" symlink to the physical device
 109          * if device is set to NULL, no devices in that subsystem has a link */
 110         static struct class_device {
 111                 char *subsystem;
 112                 char *device;
 113         } class_device[] = {
 114                 { .subsystem = "block",         .device = "double" },
 115                 { .subsystem = "block",         .device = "nb" },
 116                 { .subsystem = "block",         .device = "ram" },
 117                 { .subsystem = "block",         .device = "loop" },
 118                 { .subsystem = "block",         .device = "fd" },
 119                 { .subsystem = "block",         .device = "md" },
 120                 { .subsystem = "block",         .device = "dos_cd" },
 121                 { .subsystem = "block",         .device = "rflash" },
 122                 { .subsystem = "block",         .device = "rom" },
 123                 { .subsystem = "block",         .device = "rrom" },
 124                 { .subsystem = "block",         .device = "flash" },
 125                 { .subsystem = "block",         .device = "msd" },
 126                 { .subsystem = "block",         .device = "sbpcd" },
 127                 { .subsystem = "block",         .device = "pcd" },
 128                 { .subsystem = "block",         .device = "pf" },
 129                 { .subsystem = "block",         .device = "scd" },
 130                 { .subsystem = "block",         .device = "ubd" },
 131                 { .subsystem = "input",         .device = "event" },
 132                 { .subsystem = "input",         .device = "mice" },
 133                 { .subsystem = "input",         .device = "mouse" },
 134                 { .subsystem = "input",         .device = "ts" },
 135                 { .subsystem = "vc",            .device = NULL },
 136                 { .subsystem = "tty",           .device = NULL },
 137                 { .subsystem = "cpuid",         .device = "cpu" },
 138                 { .subsystem = "graphics",      .device = "fb" },
 139                 { .subsystem = "mem",           .device = NULL },
 140                 { .subsystem = "misc",          .device = NULL },
 141                 { .subsystem = "msr",           .device = NULL },
 142                 { .subsystem = "netlink",       .device = NULL },
 143                 { .subsystem = "net",           .device = "sit" },
 144                 { .subsystem = "net",           .device = "ppp" },
 145                 { .subsystem = "net",           .device = "lo" },
 146                 { .subsystem = "net",           .device = "tap" },
 147                 { .subsystem = "net",           .device = "ipsec" },
 148                 { .subsystem = "net",           .device = "irda" },
 149                 { .subsystem = "sound",         .device = NULL },
 150                 { .subsystem = "printer",       .device = "lp" },
 151                 { .subsystem = "nvidia",        .device = NULL },
 152                 { .subsystem = "video4linux",   .device = "vbi" },
 153                 { .subsystem = "lirc",          .device = NULL },
 154                 { .subsystem = "firmware",      .device = NULL },
 155                 { .subsystem = "drm",           .device = NULL },
 156                 { .subsystem = "pci_bus",       .device = NULL },
 157                 { .subsystem = "ieee1394",      .device = NULL },
 158                 { .subsystem = "ieee1394_host", .device = NULL },
 159                 { .subsystem = "ieee1394_node", .device = NULL },
 160                 { .subsystem = "raw",           .device = NULL },
 161                 { NULL, NULL }
 162         };
 163         struct class_device *classdevice;
 164         int len;
 165
 166         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 167                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 168                         /* see if no device in this class is expected to have a device-link */
 169                         if (classdevice->device == NULL)
 170                                 return 1;
 171
 172                         len = strlen(classdevice->device);
 173
 174                         /* see if device name matches */
 175                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 176                                 continue;
 177
 178                         /* exact name match */
 179                         if (strlen(class_dev->name) == len)
 180                                 return 1;
 181
 182                         /* name match with instance number */
 183                         if (isdigit(class_dev->name[len]))
 184                                 return 1;
 185                 }
 186         }
 187
 188         return 0;
 189 }
 190
 191 /* skip waiting for the bus */
 192 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 193 {
 194         static char *devices_without_bus[] = {
 195                 "scsi_host",
 196                 "i2c-adapter",
 197                 NULL
 198         };
 199         char **device;
 200
 201         for (device = devices_without_bus; *device != NULL; device++) {
 202                 int len = strlen(*device);
 203
 204                 if (strncmp(class_dev->classname, *device, len) == 0)
 205                         return 1;
 206         }
 207
 208         return 0;
 209 }
 210
 211 /* wait for the bus and for a bus specific file to show up */
 212 static int wait_for_bus_device(struct sysfs_device *device_dev)
 213 {
 214         static struct bus_file {
 215                 char *bus;
 216                 char *file;
 217         } bus_files[] = {
 218                 { .bus = "scsi",        .file = "vendor" },
 219                 { .bus = "usb",         .file = "idVendor" },
 220                 { .bus = "usb",         .file = "iInterface" },
 221                 { .bus = "usb",         .file = "bNumEndpoints" },
 222                 { .bus = "usb-serial",  .file = "detach_state" },
 223                 { .bus = "ide",         .file = "detach_state" },
 224                 { .bus = "pci",         .file = "vendor" },
 225                 { .bus = "platform",    .file = "detach_state" },
 226                 { .bus = "i2c",         .file = "detach_state" },
 227                 { NULL }
 228         };
 229         struct bus_file *busfile;
 230         int loop;
 231
 232         /* wait for the /bus-device link to the /device-device */
 233         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 234         while (--loop) {
 235                 if (sysfs_get_device_bus(device_dev) == 0)
 236                         break;
 237
 238                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 239         }
 240         if (loop == 0) {
 241                 dbg("error: getting /bus-device link");
 242                 return -1;
 243         }
 244         dbg("/bus-device link found for bus '%s'", device_dev->bus);
 245
 246         /* wait for a bus specific file to show up */
 247         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 248         while (--loop) {
 249                 int found = 0;
 250
 251                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 252                         if (strcmp(device_dev->bus, busfile->bus) == 0) {
 253                                 found = 1;
 254                                 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
 255                                 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
 256                                         dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
 257                                         return 0;
 258                                 }
 259                         }
 260                 }
 261                 if (found == 0) {
 262                         info("error: unknown bus, please report to "
 263                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
 264                         return -1;
 265                 }
 266                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 267         }
 268
 269         dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
 270         return -1;
 271 }
 272
 273 int main(int argc, char *argv[], char *envp[])
 274 {
 275         const char *devpath = "";
 276         const char *action;
 277         const char *subsystem;
 278         char sysfs_path[SYSFS_PATH_MAX];
 279         char filename[SYSFS_PATH_MAX];
 280         struct sysfs_class_device *class_dev;
 281         struct sysfs_class_device *class_dev_parent;
 282         struct sysfs_device *device_dev = NULL;
 283         int loop;
 284         int rc = 0;
 285
 286         init_logging("wait_for_sysfs");
 287
 288         if (argc != 2) {
 289                 dbg("error: subsystem");
 290                 return 1;
 291         }
 292         subsystem = argv[1];
 293
 294         devpath = getenv ("DEVPATH");
 295         if (!devpath) {
 296                 dbg("error: no DEVPATH");
 297                 return 1;
 298         }
 299
 300         action = getenv ("ACTION");
 301         if (!action) {
 302                 dbg("error: no ACTION");
 303                 return 1;
 304         }
 305
 306         /* we only wait on an add event */
 307         if (strcmp(action, "add") != 0)
 308                 return 0;
 309
 310         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 311                 dbg("error: no sysfs path");
 312                 return 2;
 313         }
 314
 315         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 316                 /* open the class device we are called for */
 317                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 318                 filename[SYSFS_PATH_MAX-1] = '\0';
 319
 320                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 321                 while (--loop) {
 322                         class_dev = sysfs_open_class_device_path(filename);
 323                         if (class_dev)
 324                                 break;
 325
 326                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 327                 }
 328                 if (class_dev == NULL) {
 329                         dbg("error: getting class_device");
 330                         rc = 3;
 331                         goto exit;
 332                 }
 333                 dbg("class_device opened '%s'", filename);
 334
 335                 if (wait_for_class_device_attributes(class_dev) != 0) {
 336                         rc = 4;
 337                         goto exit_class;
 338                 }
 339
 340                 /* skip devices without /device-link */
 341                 if (class_device_expect_no_device_link(class_dev)) {
 342                         dbg("no device symlink expected for '%s', ", class_dev->name);
 343                         goto exit_class;
 344                 }
 345
 346                 /* the symlink may be on the parent device */
 347                 class_dev_parent = sysfs_get_classdev_parent(class_dev);
 348                 if (class_dev_parent)
 349                         dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 350
 351                 /* wait for the symlink to the /device-device */
 352                 dbg("waiting for symlink to /device-device");
 353                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 354                 while (--loop) {
 355                         if (class_dev_parent)
 356                                 device_dev = sysfs_get_classdev_device(class_dev_parent);
 357                         else
 358                                 device_dev = sysfs_get_classdev_device(class_dev);
 359
 360                         if (device_dev)
 361                                 break;
 362
 363                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 364                 }
 365                 if (device_dev == NULL) {
 366                         dbg("error: getting /device-device");
 367                         rc = 5;
 368                         goto exit_class;
 369                 }
 370                 dbg("device symlink found pointing to '%s'", device_dev->path);
 371
 372                 /* wait for the bus value */
 373                 if (class_device_expect_no_bus(class_dev)) {
 374                         dbg("no bus device expected for '%s', ", class_dev->classname);
 375                 } else {
 376                         if (wait_for_bus_device(device_dev) != 0)
 377                                 rc = 6;
 378                 }
 379
 380 exit_class:
 381                 sysfs_close_class_device(class_dev);
 382
 383         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 384                 /* open the path we are called for */
 385                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 386                 filename[SYSFS_PATH_MAX-1] = '\0';
 387
 388                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 389                 while (--loop) {
 390                         device_dev = sysfs_open_device_path(filename);
 391                         if (device_dev)
 392                                 break;
 393
 394                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 395                 }
 396                 if (device_dev == NULL) {
 397                         dbg("error: getting /device-device");
 398                         rc = 7;
 399                         goto exit;
 400                 }
 401                 dbg("device_device opened '%s'", filename);
 402
 403                 /* wait for the bus value */
 404                 if (wait_for_bus_device(device_dev) != 0)
 405                         rc = 8;
 406
 407                 sysfs_close_device(device_dev);
 408
 409         } else {
 410                 dbg("unhandled sysfs path, no need to wait");
 411         }
 412
 413 exit:
 414         if (rc == 0)
 415                 dbg("result: waiting for sysfs successful '%s'", devpath);
 416         else
 417                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 418                      "properly (%d) or the sysfs-support of your device's driver needs to be fixed, "
 419                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 420                      UDEV_VERSION, devpath, rc);
 421
 422         return rc;
 423 }