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                 { .subsystem = "pci_bus",       .file = NULL },
  67                 { .subsystem = "ieee1394",      .file = NULL },
  68                 { .subsystem = "ieee1394_host", .file = NULL },
  69                 { .subsystem = "ieee1394_node", .file = NULL },
  70                 { NULL, NULL }
  71         };
  72         struct class_file *classfile;
  73         const char *file = "dev";
  74         int loop;
  75
  76         /* look if we want to look for another file instead of "dev" */
  77         for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
  78                 if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
  79                         if (classfile->file == NULL) {
  80                                 dbg("class '%s' has no file to wait for", class_dev->classname);
  81                                 return 0;
  82                         }
  83                         file = classfile->file;
  84                         break;
  85                 }
  86         }
  87         dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
  88
  89         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
  90         while (--loop) {
  91                 if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
  92                         dbg("class '%s' specific file '%s' found", class_dev->classname, file);
  93                         return 0;
  94                 }
  95
  96                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
  97         }
  98
  99         dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
 100         return -1;
 101 }
 102
 103 /* skip waiting for physical device */
 104 static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
 105 {
 106         /* List of devices without a "device" symlink
 107          * set .device to NULL to accept all devices in that subsystem */
 108         static struct class_device {
 109                 char *subsystem;
 110                 char *device;
 111         } class_device[] = {
 112                 { .subsystem = "block",         .device = "double" },
 113                 { .subsystem = "block",         .device = "nb" },
 114                 { .subsystem = "block",         .device = "ram" },
 115                 { .subsystem = "block",         .device = "loop" },
 116                 { .subsystem = "block",         .device = "fd" },
 117                 { .subsystem = "block",         .device = "md" },
 118                 { .subsystem = "block",         .device = "dos_cd" },
 119                 { .subsystem = "block",         .device = "rflash" },
 120                 { .subsystem = "block",         .device = "rom" },
 121                 { .subsystem = "block",         .device = "rrom" },
 122                 { .subsystem = "block",         .device = "flash" },
 123                 { .subsystem = "block",         .device = "msd" },
 124                 { .subsystem = "block",         .device = "sbpcd" },
 125                 { .subsystem = "block",         .device = "pcd" },
 126                 { .subsystem = "block",         .device = "pf" },
 127                 { .subsystem = "block",         .device = "scd" },
 128                 { .subsystem = "block",         .device = "ubd" },
 129                 { .subsystem = "input",         .device = "event" },
 130                 { .subsystem = "input",         .device = "mice" },
 131                 { .subsystem = "input",         .device = "mouse" },
 132                 { .subsystem = "input",         .device = "ts" },
 133                 { .subsystem = "vc",            .device = NULL },
 134                 { .subsystem = "tty",           .device = NULL },
 135                 { .subsystem = "cpuid",         .device = "cpu" },
 136                 { .subsystem = "graphics",      .device = "fb" },
 137                 { .subsystem = "mem",           .device = NULL },
 138                 { .subsystem = "misc",          .device = NULL },
 139                 { .subsystem = "msr",           .device = NULL },
 140                 { .subsystem = "netlink",       .device = NULL },
 141                 { .subsystem = "net",           .device = NULL },
 142                 { .subsystem = "sound",         .device = NULL },
 143                 { .subsystem = "printer",       .device = "lp" },
 144                 { .subsystem = "nvidia",        .device = NULL },
 145                 { .subsystem = "video4linux",   .device = NULL },
 146                 { .subsystem = "lirc",          .device = NULL },
 147                 { .subsystem = "firmware",      .device = NULL },
 148                 { .subsystem = "drm",           .device = NULL },
 149                 { .subsystem = "pci_bus",       .device = NULL },
 150                 { .subsystem = "ieee1394",      .device = NULL },
 151                 { .subsystem = "ieee1394_host", .device = NULL },
 152                 { .subsystem = "ieee1394_node", .device = NULL },
 153                 { NULL, NULL }
 154         };
 155         struct class_device *classdevice;
 156         int len;
 157
 158         /* look if we want to look for another file instead of "dev" */
 159         for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
 160                 if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
 161                         /* if device is NULL, all devices in this class are ok */
 162                         if (classdevice->device == NULL)
 163                                 return 1;
 164
 165                         len = strlen(classdevice->device);
 166
 167                         /* see if device name matches */
 168                         if (strncmp(class_dev->name, classdevice->device, len) != 0)
 169                                 continue;
 170
 171                         /* exact match */
 172                         if (strlen(class_dev->name) == len)
 173                                 return 1;
 174
 175                         /* instance numbers are matching too */
 176                         if (isdigit(class_dev->name[len]))
 177                                 return 1;
 178                 }
 179         }
 180
 181         return 0;
 182 }
 183
 184 /* skip waiting for the bus */
 185 static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
 186 {
 187         static char *devices_without_bus[] = {
 188                 "scsi_host",
 189                 "i2c-adapter",
 190                 NULL
 191         };
 192         char **device;
 193
 194         for (device = devices_without_bus; *device != NULL; device++) {
 195                 int len = strlen(*device);
 196
 197                 if (strncmp(class_dev->classname, *device, len) == 0)
 198                         return 1;
 199         }
 200
 201         return 0;
 202 }
 203
 204 /* wait for the bus and for a bus specific file to show up */
 205 static int wait_for_bus_device(struct sysfs_device *device_dev)
 206 {
 207         static struct bus_file {
 208                 char *bus;
 209                 char *file;
 210         } bus_files[] = {
 211                 { .bus = "scsi",        .file = "vendor" },
 212                 { .bus = "usb",         .file = "idVendor" },
 213                 { .bus = "usb",         .file = "iInterface" },
 214                 { .bus = "usb",         .file = "bNumEndpoints" },
 215                 { .bus = "usb-serial",  .file = "detach_state" },
 216                 { .bus = "ide",         .file = "detach_state" },
 217                 { .bus = "pci",         .file = "vendor" },
 218                 { .bus = "platform",    .file = "detach_state" },
 219                 { .bus = "i2c",         .file = "detach_state" },
 220                 { NULL }
 221         };
 222         struct bus_file *busfile;
 223         int loop;
 224
 225         /* wait for the /bus-device link to the /device-device */
 226         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 227         while (--loop) {
 228                 if (sysfs_get_device_bus(device_dev) == 0)
 229                         break;
 230
 231                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 232         }
 233         if (loop == 0) {
 234                 dbg("error: getting /bus-device link");
 235                 return -1;
 236         }
 237         dbg("/bus-device link found for bus '%s'", device_dev->bus);
 238
 239         /* wait for a bus specific file to show up */
 240         loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 241         while (--loop) {
 242                 int found = 0;
 243
 244                 for (busfile = bus_files; busfile->bus != NULL; busfile++) {
 245                         if (strcmp(device_dev->bus, busfile->bus) == 0) {
 246                                 found = 1;
 247                                 dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
 248                                 if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
 249                                         dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
 250                                         return 0;
 251                                 }
 252                         }
 253                 }
 254                 if (found == 0) {
 255                         info("error: unknown bus, please report to "
 256                              "<linux-hotplug-devel@lists.sourceforge.net> '%s'", device_dev->bus);
 257                         return -1;
 258                 }
 259                 usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 260         }
 261
 262         dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
 263         return -1;
 264 }
 265
 266 int main(int argc, char *argv[], char *envp[])
 267 {
 268         const char *devpath = "";
 269         const char *action;
 270         const char *subsystem;
 271         char sysfs_path[SYSFS_PATH_MAX];
 272         char filename[SYSFS_PATH_MAX];
 273         struct sysfs_class_device *class_dev;
 274         struct sysfs_class_device *class_dev_parent;
 275         struct sysfs_device *device_dev = NULL;
 276         int loop;
 277         int rc = 0;
 278
 279         init_logging("wait_for_sysfs");
 280
 281         if (argc != 2) {
 282                 dbg("error: subsystem");
 283                 return 1;
 284         }
 285         subsystem = argv[1];
 286
 287         devpath = getenv ("DEVPATH");
 288         if (!devpath) {
 289                 dbg("error: no DEVPATH");
 290                 return 1;
 291         }
 292
 293         action = getenv ("ACTION");
 294         if (!action) {
 295                 dbg("error: no ACTION");
 296                 return 1;
 297         }
 298
 299         /* we only wait on an add event */
 300         if (strcmp(action, "add") != 0)
 301                 return 0;
 302
 303         if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
 304                 dbg("error: no sysfs path");
 305                 return 2;
 306         }
 307
 308         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
 309                 /* open the class device we are called for */
 310                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 311                 filename[SYSFS_PATH_MAX-1] = '\0';
 312
 313                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 314                 while (--loop) {
 315                         class_dev = sysfs_open_class_device_path(filename);
 316                         if (class_dev)
 317                                 break;
 318
 319                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 320                 }
 321                 if (class_dev == NULL) {
 322                         dbg("error: getting class_device");
 323                         rc = 3;
 324                         goto exit;
 325                 }
 326                 dbg("class_device opened '%s'", filename);
 327
 328                 if (wait_for_class_device_attributes(class_dev) != 0) {
 329                         rc = 4;
 330                         goto exit_class;
 331                 }
 332
 333                 /* skip devices without /device-link */
 334                 if (class_device_expect_no_device_link(class_dev)) {
 335                         dbg("no device symlink expected for '%s', ", class_dev->name);
 336                         goto exit_class;
 337                 }
 338
 339                 /* the symlink may be on the parent device */
 340                 class_dev_parent = sysfs_get_classdev_parent(class_dev);
 341                 if (class_dev_parent)
 342                         dbg("looking at parent device for device link '%s'", class_dev_parent->path);
 343
 344                 /* wait for the symlink to the /device-device */
 345                 dbg("waiting for symlink to /device-device");
 346                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 347                 while (--loop) {
 348                         if (class_dev_parent)
 349                                 device_dev = sysfs_get_classdev_device(class_dev_parent);
 350                         else
 351                                 device_dev = sysfs_get_classdev_device(class_dev);
 352
 353                         if (device_dev)
 354                                 break;
 355
 356                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 357                 }
 358                 if (device_dev == NULL) {
 359                         dbg("error: getting /device-device");
 360                         rc = 5;
 361                         goto exit_class;
 362                 }
 363                 dbg("device symlink found pointing to '%s'", device_dev->path);
 364
 365                 /* wait for the bus value */
 366                 if (class_device_expect_no_bus(class_dev)) {
 367                         dbg("no bus device expected for '%s', ", class_dev->classname);
 368                 } else {
 369                         if (wait_for_bus_device(device_dev) != 0)
 370                                 rc = 6;
 371                 }
 372
 373 exit_class:
 374                 sysfs_close_class_device(class_dev);
 375
 376         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 377                 /* open the path we are called for */
 378                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
 379                 filename[SYSFS_PATH_MAX-1] = '\0';
 380
 381                 loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
 382                 while (--loop) {
 383                         device_dev = sysfs_open_device_path(filename);
 384                         if (device_dev)
 385                                 break;
 386
 387                         usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
 388                 }
 389                 if (device_dev == NULL) {
 390                         dbg("error: getting /device-device");
 391                         rc = 7;
 392                         goto exit;
 393                 }
 394                 dbg("device_device opened '%s'", filename);
 395
 396                 /* wait for the bus value */
 397                 if (wait_for_bus_device(device_dev) != 0)
 398                         rc = 8;
 399
 400                 sysfs_close_device(device_dev);
 401
 402         } else {
 403                 dbg("unhandled sysfs path, no need to wait");
 404         }
 405
 406 exit:
 407         if (rc == 0)
 408                 dbg("result: waiting for sysfs successful '%s'", devpath);
 409         else
 410                 info("error: wait_for_sysfs needs an update to handle the device '%s' "
 411                      "properly, please report to <linux-hotplug-devel@lists.sourceforge.net>",
 412                      devpath);
 413
 414         return rc;
 415 }