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 "libsysfs/sysfs/libsysfs.h"
  36
  37 #ifdef LOG
  38 unsigned char logname[LOGNAME_SIZE];
  39 void log_message(int level, const char *format, ...)
  40 {
  41         va_list args;
  42
  43         va_start(args, format);
  44         vsyslog(level, format, args);
  45         va_end(args);
  46 }
  47 #endif
  48
  49 #define WAIT_MAX_SECONDS                5
  50 #define WAIT_LOOP_PER_SECOND            20
  51
  52 /* wait for specific file to show up, normally the "dev"-file */
  53 static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
  54 {
  55         static struct class_file {
  56                 char *subsystem;
  57                 char *file;
  58         } class_files[] = {
  59                 { .subsystem = "net",           .file = "ifindex" },
  60                 { .subsystem = "scsi_host",     .file = "unique_id" },
  61                 { .subsystem = "scsi_device",   .file = NULL },
  62                 { .subsystem = "pcmcia_socket", .file = "card_type" },
  63                 { .subsystem = "usb_host",      .file = NULL },
  64                 { .subsystem = "bluetooth",     .file = "address" },
  65                 { .subsystem = "i2c-adapter",   .file = NULL },
  66                 { NULL, NULL }
  67         };
  68         struct class_file *classfile;
  69         const char *file = "dev";
  70         int loop;
  71
  72         /* look if we want to look for another file instead of "dev" */
  73         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  74                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  75                         if (classfile->file == NULL) {
  76                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  77                                 return 0;
  78                         }
  79                         file = classfile->file;
  80                         break;
  81                 }
  82         }
  83         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
  84
  85         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
  86         while (--loop) {
  87                 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
  88                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
  89                         return 0;
  90                 }
  91
  92                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
  93         }
  94
  95         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
  96         return -1;
  97 }
  98
  99 /* skip waiting for physical device */
 100 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 101 {
 102         /* List of devices without a "device" symlink
 103          * set .device to NULL to accept all devices in that subsystem */
 104         static struct class_device {
 105                 char *subsystem;
 106                 char *device;
 107         } class_device[] = {
 108                 { .subsystem = "block",         .device = "double" },
 109                 { .subsystem = "block",         .device = "nb" },
 110                 { .subsystem = "block",         .device = "ram" },
 111                 { .subsystem = "block",         .device = "loop" },
 112                 { .subsystem = "block",         .device = "fd" },
 113                 { .subsystem = "block",         .device = "md" },
 114                 { .subsystem = "block",         .device = "dos_cd" },
 115                 { .subsystem = "block",         .device = "rflash" },
 116                 { .subsystem = "block",         .device = "rom" },
 117                 { .subsystem = "block",         .device = "rrom" },
 118                 { .subsystem = "block",         .device = "flash" },
 119                 { .subsystem = "block",         .device = "msd" },
 120                 { .subsystem = "block",         .device = "sbpcd" },
 121                 { .subsystem = "block",         .device = "pcd" },
 122                 { .subsystem = "block",         .device = "pf" },
 123                 { .subsystem = "block",         .device = "scd" },
 124                 { .subsystem = "block",         .device = "ubd" },
 125                 { .subsystem = "input",         .device = "event" },
 126                 { .subsystem = "input",         .device = "mice" },
 127                 { .subsystem = "input",         .device = "mouse" },
 128                 { .subsystem = "input",         .device = "ts" },
 129                 { .subsystem = "vc",            .device = "vcs" },
 130                 { .subsystem = "vc",            .device = "vcsa" },
 131                 { .subsystem = "tty",           .device = NULL },
 132                 { .subsystem = "cpuid",         .device = "cpu" },
 133                 { .subsystem = "graphics",      .device = "fb" },
 134                 { .subsystem = "mem",           .device = NULL },
 135                 { .subsystem = "misc",          .device = NULL },
 136                 { .subsystem = "msr",           .device = NULL },
 137                 { .subsystem = "netlink",       .device = NULL },
 138                 { .subsystem = "sound",         .device = NULL },
 139                 { .subsystem = "snd",           .device = NULL },
 140                 { .subsystem = "printer",       .device = "lp" },
 141                 { NULL, NULL }
 142         };
 143         struct class_device *classdevice;
 144         int len;
 145
 146         /* look if we want to look for another file instead of "dev" */
 147         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 148                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 149                         /* if device is NULL, all devices in this class are ok */
 150                         if (classdevice->device == NULL)
 151                                 return 1;
 152
 153                         len = strlen(classdevice->device);
 154
 155                         /* see if device name matches */
 156                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 157                                 continue;
 158
 159                         /* exact match */
 160                         if (strlen(class_dev->name) == len)
 161                                 return 1;
 162
 163                         /* instance numbers are matching too */
 164                         if (isdigit(class_dev->name[len]))
 165                                 return 1;
 166                 }
 167         }
 168
 169         return 0;
 170 }
 171
 172 /* skip waiting for the bus */
 173 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 174 {
 175         static char *devices_without_bus[] = {
 176                 "scsi_host",
 177                 "i2c-adapter",
 178                 NULL
 179         };
 180         char **device;
 181
 182         for (device = devices_without_bus; *device != NULL; device++) {
 183                 int len = strlen(*device);
 184
 185                 if (strncmp(class_dev->classname, *device, len) == 0)
 186                         return 1;
 187         }
 188
 189         return 0;
 190 }
 191
 192 /* wait for the bus and for a bus specific file to show up */
 193 static int wait_for_bus_device(struct sysfs_device *device_dev)
 194 {
 195         static struct bus_file {
 196                 char *bus;
 197                 char *file;
 198         } bus_files[] = {
 199                 { .bus = "scsi",        .file = "vendor" },
 200                 { .bus = "usb",         .file = "idVendor" },
 201                 { .bus = "usb",         .file = "iInterface" },
 202                 { .bus = "usb",         .file = "bNumEndpoints" },
 203                 { .bus = "usb-serial",  .file = "detach_state" },
 204                 { .bus = "ide",         .file = "detach_state" },
 205                 { .bus = "pci",         .file = "vendor" },
 206                 { .bus = "platform",    .file = "detach_state" },
 207                 { .bus = "i2c",         .file = "detach_state" },
 208                 { NULL }
 209         };
 210         struct bus_file *busfile;
 211         int loop;
 212
 213         /* wait for the /bus-device link to the /device-device */
 214         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 215         while (--loop) {
 216                 if (sysfs_get_device_bus(device_dev) == 0)
 217                         break;
 218
 219                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 220         }
 221         if (loop == 0) {
 222                 dbg("error: getting /bus-device link");
 223                 return -1;
 224         }
 225         dbg("/bus-device link found for bus '%s'", device_dev->bus);
 226
 227         /* wait for a bus specific file to show up */
 228         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 229         while (--loop) {
 230                 int found = 0;
 231
 232                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 233                         if (strcmp(device_dev->bus, busfile->bus) == 0) {
 234                                 found = 1;
 235                                 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
 236                                 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
 237                                         dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
 238                                         return 0;
 239                                 }
 240                         }
 241                 }
 242                 if (found == 0) {
 243                         info("error: unknown bus, please report to "
 244                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
 245                         return -1;
 246                 }
 247                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 248         }
 249
 250         dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
 251         return -1;
 252 }
 253
 254 int main(int argc, char *argv[], char *envp[])
 255 {
 256         const char *devpath = "";
 257         const char *action;
 258         const char *subsystem;
 259         char sysfs_path[SYSFS_PATH_MAX];
 260         char filename[SYSFS_PATH_MAX];
 261         struct sysfs_class_device *class_dev;
 262         struct sysfs_class_device *class_dev_parent;
 263         struct sysfs_device *device_dev = NULL;
 264         int loop;
 265         int rc = 0;
 266
 267         init_logging("wait_for_sysfs");
 268
 269         if (argc != 2) {
 270                 dbg("error: subsystem");
 271                 return 1;
 272         }
 273         subsystem = argv[1];
 274
 275         devpath = getenv ("DEVPATH");
 276         if (!devpath) {
 277                 dbg("error: no DEVPATH");
 278                 return 1;
 279         }
 280
 281         action = getenv ("ACTION");
 282         if (!action) {
 283                 dbg("error: no ACTION");
 284                 return 1;
 285         }
 286
 287         /* we only wait on an add event */
 288         if (strcmp(action, "add") != 0)
 289                 return 0;
 290
 291         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 292                 dbg("error: no sysfs path");
 293                 return 2;
 294         }
 295
 296         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 297                 /* open the class device we are called for */
 298                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 299                 filename[SYSFS_PATH_MAX-1] = '\0';
 300
 301                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 302                 while (--loop) {
 303                         class_dev = sysfs_open_class_device_path(filename);
 304                         if (class_dev)
 305                                 break;
 306
 307                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 308                 }
 309                 if (class_dev == NULL) {
 310                         dbg("error: getting class_device");
 311                         rc = 3;
 312                         goto exit;
 313                 }
 314                 dbg("class_device opened '%s'", filename);
 315
 316                 if (wait_for_class_device_attributes(class_dev) != 0) {
 317                         rc = 4;
 318                         goto exit_class;
 319                 }
 320
 321                 /* skip devices without /device-link */
 322                 if (class_device_expect_no_device_link(class_dev)) {
 323                         dbg("no device symlink expected for '%s', ", class_dev->name);
 324                         goto exit_class;
 325                 }
 326
 327                 /* the symlink may be on the parent device */
 328                 class_dev_parent = sysfs_get_classdev_parent(class_dev);
 329                 if (class_dev_parent)
 330                         dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 331
 332                 /* wait for the symlink to the /device-device */
 333                 dbg("waiting for symlink to /device-device");
 334                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 335                 while (--loop) {
 336                         if (class_dev_parent)
 337                                 device_dev = sysfs_get_classdev_device(class_dev_parent);
 338                         else
 339                                 device_dev = sysfs_get_classdev_device(class_dev);
 340
 341                         if (device_dev)
 342                                 break;
 343
 344                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 345                 }
 346                 if (device_dev == NULL) {
 347                         dbg("error: getting /device-device");
 348                         rc = 5;
 349                         goto exit_class;
 350                 }
 351                 dbg("device symlink found pointing to '%s'", device_dev->path);
 352
 353                 /* wait for the bus value */
 354                 if (class_device_expect_no_bus(class_dev)) {
 355                         dbg("no bus device expected for '%s', ", class_dev->classname);
 356                 } else {
 357                         if (wait_for_bus_device(device_dev) != 0)
 358                                 rc = 6;
 359                 }
 360
 361 exit_class:
 362                 sysfs_close_class_device(class_dev);
 363
 364         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 365                 /* open the path we are called for */
 366                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 367                 filename[SYSFS_PATH_MAX-1] = '\0';
 368
 369                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 370                 while (--loop) {
 371                         device_dev = sysfs_open_device_path(filename);
 372                         if (device_dev)
 373                                 break;
 374
 375                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 376                 }
 377                 if (device_dev == NULL) {
 378                         dbg("error: getting /device-device");
 379                         rc = 7;
 380                         goto exit;
 381                 }
 382                 dbg("device_device opened '%s'", filename);
 383
 384                 /* wait for the bus value */
 385                 if (wait_for_bus_device(device_dev) != 0)
 386                         rc = 8;
 387
 388                 sysfs_close_device(device_dev);
 389
 390         } else {
 391                 dbg("unhandled sysfs path, no need to wait");
 392         }
 393
 394 exit:
 395         if (rc == 0)
 396                 dbg("result: waiting for sysfs successful '%s'", devpath);
 397         else
 398                 info("error: wait_for_sysfs needs an update to handle the device '%s' "
 399                      "properly, please report to <linux-hotplug-devel@lists.sourceforge.net>",
 400                      devpath);
 401
 402         return rc;
 403 }