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