git.ozlabs.org Git - petitboot/blob - discover/udev.c

   1
   2 #define _GNU_SOURCE
   3
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <libudev.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <sys/socket.h>
  12 #include <sys/types.h>
  13 #include <sys/un.h>
  14
  15 #include <log/log.h>
  16 #include <types/types.h>
  17 #include <talloc/talloc.h>
  18 #include <waiter/waiter.h>
  19 #include <system/system.h>
  20
  21 #include "event.h"
  22 #include "udev.h"
  23 #include "pb-discover.h"
  24 #include "device-handler.h"
  25 #include "cdrom.h"
  26
  27 struct pb_udev {
  28         struct udev *udev;
  29         struct udev_monitor *monitor;
  30         struct device_handler *handler;
  31 };
  32
  33 static int udev_destructor(void *p)
  34 {
  35         struct pb_udev *udev = p;
  36
  37         udev_monitor_unref(udev->monitor);
  38         udev->monitor = NULL;
  39
  40         udev_unref(udev->udev);
  41         udev->udev = NULL;
  42
  43         return 0;
  44 }
  45
  46 static void udev_setup_device_params(struct udev_device *udev,
  47                 struct discover_device *dev)
  48 {
  49         struct udev_list_entry *list, *entry;
  50
  51         list = udev_device_get_properties_list_entry(udev);
  52         if (!list)
  53                 return;
  54
  55         udev_list_entry_foreach(entry, list)
  56                 discover_device_set_param(dev,
  57                                 udev_list_entry_get_name(entry),
  58                                 udev_list_entry_get_value(entry));
  59 }
  60
  61 static int udev_handle_dev_add(struct pb_udev *udev, struct udev_device *dev)
  62 {
  63         struct discover_device *ddev;
  64         const char *typestr;
  65         const char *uuid;
  66         const char *path;
  67         const char *name;
  68         const char *node;
  69         const char *prop;
  70         bool cdrom;
  71
  72         name = udev_device_get_sysname(dev);
  73         if (!name) {
  74                 pb_debug("udev_device_get_sysname failed\n");
  75                 return -1;
  76         }
  77
  78         typestr = udev_device_get_devtype(dev);
  79         if (!typestr) {
  80                 pb_debug("udev_device_get_devtype failed\n");
  81                 return -1;
  82         }
  83
  84         if (!(!strcmp(typestr, "disk") || !strcmp(typestr, "partition"))) {
  85                 pb_debug("SKIP %s: invalid type %s\n", name, typestr);
  86                 return 0;
  87         }
  88
  89         node = udev_device_get_devnode(dev);
  90         path = udev_device_get_devpath(dev);
  91         if (path && (strstr(path, "virtual/block/loop")
  92                         || strstr(path, "virtual/block/ram"))) {
  93                 pb_debug("SKIP: %s: ignored (path=%s)\n", name, path);
  94                 return 0;
  95         }
  96
  97         cdrom = node && !!udev_device_get_property_value(dev, "ID_CDROM");
  98         if (cdrom) {
  99                 /* CDROMs require a little initialisation, to get
 100                  * petitboot-compatible tray behaviour */
 101                 cdrom_init(node);
 102                 if (!cdrom_media_present(node)) {
 103                         pb_debug("SKIP: %s: no media present\n", name);
 104                         return 0;
 105                 }
 106         }
 107
 108         /* We have enough info to create the device and start discovery */
 109         ddev = device_lookup_by_id(udev->handler, name);
 110         if (ddev) {
 111                 pb_debug("device %s is already present?\n", name);
 112                 return -1;
 113         }
 114
 115         /* We may see multipath devices; they'll have the same uuid as an
 116          * existing device, so only parse the first. */
 117         uuid = udev_device_get_property_value(dev, "ID_FS_UUID");
 118         if (uuid) {
 119                 ddev = device_lookup_by_uuid(udev->handler, uuid);
 120                 if (ddev) {
 121                         pb_log("SKIP: %s UUID [%s] already present (as %s)\n",
 122                                         name, uuid, ddev->device->id);
 123                         return -1;
 124                 }
 125         }
 126
 127         ddev = discover_device_create(udev->handler, name);
 128
 129         ddev->device_path = talloc_strdup(ddev, node);
 130
 131         if (uuid)
 132                 ddev->uuid = talloc_strdup(ddev, uuid);
 133         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 134         if (prop)
 135                 ddev->label = talloc_strdup(ddev, prop);
 136         ddev->device->type = DEVICE_TYPE_DISK;
 137
 138         udev_setup_device_params(dev, ddev);
 139
 140         device_handler_discover(udev->handler, ddev);
 141
 142         return 0;
 143 }
 144
 145 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 146 {
 147         struct discover_device *ddev;
 148         const char *name;
 149
 150         name = udev_device_get_sysname(dev);
 151         if (!name) {
 152                 pb_debug("udev_device_get_sysname failed\n");
 153                 return -1;
 154         }
 155
 156         ddev = device_lookup_by_id(udev->handler, name);
 157         if (!ddev)
 158                 return 0;
 159
 160         device_handler_remove(udev->handler, ddev);
 161
 162         return 0;
 163 }
 164
 165 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 166 {
 167         struct discover_device *ddev;
 168         const char *name, *node;
 169
 170         name = udev_device_get_sysname(dev);
 171         node = udev_device_get_devnode(dev);
 172
 173         /* we're only interested in CDROM change events at present */
 174         if (!udev_device_get_property_value(dev, "ID_CDROM"))
 175                 return 0;
 176
 177         /* handle CDROM eject requests */
 178         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 179                 bool eject = false;
 180
 181                 pb_debug("udev: eject request\n");
 182
 183                 /* If the device is mounted, cdrom_id's own eject request may
 184                  * have failed. So, we'll need to do our own here.
 185                  */
 186                 ddev = device_lookup_by_id(udev->handler, name);
 187                 if (ddev) {
 188                         eject = ddev->mounted;
 189                         udev_handle_dev_remove(udev, dev);
 190                 }
 191
 192                 if (eject)
 193                         cdrom_eject(node);
 194
 195                 return 0;
 196         }
 197
 198         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 199                 if (cdrom_media_present(node))
 200                         return udev_handle_dev_add(udev, dev);
 201                 else
 202                         return udev_handle_dev_remove(udev, dev);
 203         }
 204
 205         return 0;
 206 }
 207
 208 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 209 {
 210         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 211
 212 #ifdef DEBUG
 213         {
 214                 struct udev_list_entry *list;
 215                 const char *name;
 216
 217                 list = udev_device_get_properties_list_entry(dev);
 218                 name = udev_device_get_sysname(dev);
 219
 220                 pb_debug("%s: action %s, device %s\n", __func__, action, name);
 221                 pb_debug("%s properties:\n", __func__);
 222
 223                 for (; list; list = udev_list_entry_get_next(list))
 224                         pb_log("\t%-20s: %s\n", udev_list_entry_get_name(list),
 225                                         udev_list_entry_get_value(list));
 226         } while (0);
 227 #endif
 228
 229         if (!strcmp(action, "add"))
 230                 return udev_handle_dev_add(udev, dev);
 231
 232         else if (!strcmp(action, "remove"))
 233                 return udev_handle_dev_remove(udev, dev);
 234
 235         else if (!strcmp(action, "change"))
 236                 return udev_handle_dev_change(udev, dev);
 237
 238         return 0;
 239 }
 240
 241 static int udev_enumerate(struct udev *udev)
 242 {
 243         int result;
 244         struct udev_list_entry *list, *entry;
 245         struct udev_enumerate *enumerate;
 246
 247         enumerate = udev_enumerate_new(udev);
 248
 249         if (!enumerate) {
 250                 pb_log("udev_enumerate_new failed\n");
 251                 return -1;
 252         }
 253
 254         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 255
 256         if (result) {
 257                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 258                 goto fail;
 259         }
 260
 261         udev_enumerate_scan_devices(enumerate);
 262
 263         list = udev_enumerate_get_list_entry(enumerate);
 264
 265         if (!list) {
 266                 pb_log("udev_enumerate_get_list_entry failed\n");
 267                 goto fail;
 268         }
 269
 270         udev_list_entry_foreach(entry, list) {
 271                 const char *syspath;
 272                 struct udev_device *dev;
 273
 274                 syspath = udev_list_entry_get_name(entry);
 275                 dev = udev_device_new_from_syspath(udev, syspath);
 276
 277                 udev_handle_dev_action(dev, "add");
 278
 279                 udev_device_unref(dev);
 280         }
 281
 282         udev_enumerate_unref(enumerate);
 283         return 0;
 284
 285 fail:
 286         udev_enumerate_unref(enumerate);
 287         return -1;
 288 }
 289
 290 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 291 {
 292         int result;
 293         struct udev_monitor *m;
 294
 295         *monitor = NULL;
 296         m = udev_monitor_new_from_netlink(udev, "udev");
 297
 298         if (!m) {
 299                 pb_log("udev_monitor_new_from_netlink failed\n");
 300                 goto out_err;
 301         }
 302
 303         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 304                 NULL);
 305
 306         if (result) {
 307                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 308                 goto out_err;
 309         }
 310
 311         result = udev_monitor_enable_receiving(m);
 312
 313         if (result) {
 314                 pb_log("udev_monitor_enable_receiving failed\n");
 315                 goto out_err;
 316         }
 317
 318         *monitor = m;
 319         return 0;
 320
 321 out_err:
 322         udev_monitor_unref(m);
 323         return -1;
 324 }
 325
 326 /*
 327  * udev_process - waiter callback for monitor netlink.
 328  */
 329
 330 static int udev_process(void *arg)
 331 {
 332         struct udev_monitor *monitor = arg;
 333         struct udev_device *dev;
 334         const char *action;
 335         int result;
 336
 337         dev = udev_monitor_receive_device(monitor);
 338
 339         if (!dev) {
 340                 pb_log("udev_monitor_receive_device failed\n");
 341                 return -1;
 342         }
 343
 344         action = udev_device_get_action(dev);
 345
 346         if (!action) {
 347                 pb_log("udev_device_get_action failed\n");
 348                 goto fail;
 349         }
 350
 351         result = udev_handle_dev_action(dev, action);
 352
 353         udev_device_unref(dev);
 354         return result;
 355
 356 fail:
 357         udev_device_unref(dev);
 358         return -1;
 359 }
 360
 361 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 362         int __attribute__((unused)) priority, const char *file, int line,
 363         const char *fn, const char *format, va_list args)
 364 {
 365       pb_log("libudev: %s %s:%d: ", fn, file, line);
 366       vfprintf(pb_log_get_stream(), format, args);
 367 }
 368
 369 struct pb_udev *udev_init(struct waitset *waitset,
 370         struct device_handler *handler)
 371 {
 372         int result;
 373         struct pb_udev *udev = talloc(NULL, struct pb_udev);
 374
 375         talloc_set_destructor(udev, udev_destructor);
 376         udev->handler = handler;
 377
 378         udev->udev = udev_new();
 379
 380         if (!udev->udev) {
 381                 pb_log("udev_new failed\n");
 382                 goto fail_new;
 383         }
 384
 385         udev_set_userdata(udev->udev, udev);
 386
 387         udev_set_log_fn(udev->udev, udev_log_fn);
 388
 389         result = udev_enumerate(udev->udev);
 390
 391         if (result)
 392                 goto fail_enumerate;
 393
 394         result = udev_setup_monitor(udev->udev, &udev->monitor);
 395
 396         if (result)
 397                 goto fail_monitor;
 398
 399         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 400                 udev_process, udev->monitor);
 401
 402         pb_debug("%s: waiting on udev\n", __func__);
 403
 404         return udev;
 405
 406 fail_monitor:
 407 fail_enumerate:
 408         udev_unref(udev->udev);
 409 fail_new:
 410         talloc_free(udev);
 411         return NULL;
 412 }
 413
 414 void udev_destroy(struct pb_udev *udev)
 415 {
 416         talloc_free(udev);
 417 }