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 *serial;
  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 also see multipath devices; same dev nodes (hence id), but
 116          * different serial numbers */
 117         serial = udev_device_get_property_value(dev, "ID_SERIAL");
 118         if (serial && device_lookup_by_serial(udev->handler, serial))
 119                 return -1;
 120
 121         ddev = discover_device_create(udev->handler, name);
 122
 123         ddev->device_path = talloc_strdup(ddev, node);
 124
 125         prop = udev_device_get_property_value(dev, "ID_FS_UUID");
 126         if (prop)
 127                 ddev->uuid = talloc_strdup(ddev, prop);
 128         prop = udev_device_get_property_value(dev, "ID_FS_LABEL");
 129         if (prop)
 130                 ddev->label = talloc_strdup(ddev, prop);
 131         ddev->device->type = DEVICE_TYPE_DISK;
 132
 133         udev_setup_device_params(dev, ddev);
 134
 135         device_handler_discover(udev->handler, ddev);
 136
 137         return 0;
 138 }
 139
 140 static int udev_handle_dev_remove(struct pb_udev *udev, struct udev_device *dev)
 141 {
 142         struct discover_device *ddev;
 143         const char *name;
 144
 145         name = udev_device_get_sysname(dev);
 146         if (!name) {
 147                 pb_debug("udev_device_get_sysname failed\n");
 148                 return -1;
 149         }
 150
 151         ddev = device_lookup_by_id(udev->handler, name);
 152         if (!ddev)
 153                 return 0;
 154
 155         device_handler_remove(udev->handler, ddev);
 156
 157         return 0;
 158 }
 159
 160 static int udev_handle_dev_change(struct pb_udev *udev, struct udev_device *dev)
 161 {
 162         struct discover_device *ddev;
 163         const char *name, *node;
 164
 165         name = udev_device_get_sysname(dev);
 166         node = udev_device_get_devnode(dev);
 167
 168         /* we're only interested in CDROM change events at present */
 169         if (!udev_device_get_property_value(dev, "ID_CDROM"))
 170                 return 0;
 171
 172         /* handle CDROM eject requests */
 173         if (udev_device_get_property_value(dev, "DISK_EJECT_REQUEST")) {
 174                 bool eject = false;
 175
 176                 pb_debug("udev: eject request\n");
 177
 178                 /* If the device is mounted, cdrom_id's own eject request may
 179                  * have failed. So, we'll need to do our own here.
 180                  */
 181                 ddev = device_lookup_by_id(udev->handler, name);
 182                 if (ddev) {
 183                         eject = ddev->mounted;
 184                         udev_handle_dev_remove(udev, dev);
 185                 }
 186
 187                 if (eject)
 188                         cdrom_eject(node);
 189
 190                 return 0;
 191         }
 192
 193         if (udev_device_get_property_value(dev, "DISK_MEDIA_CHANGE")) {
 194                 if (cdrom_media_present(node))
 195                         return udev_handle_dev_add(udev, dev);
 196                 else
 197                         return udev_handle_dev_remove(udev, dev);
 198         }
 199
 200         return 0;
 201 }
 202
 203 static int udev_handle_dev_action(struct udev_device *dev, const char *action)
 204 {
 205         struct pb_udev *udev = udev_get_userdata(udev_device_get_udev(dev));
 206
 207 #ifdef DEBUG
 208         {
 209                 struct udev_list_entry *list;
 210                 const char *name;
 211
 212                 list = udev_device_get_properties_list_entry(dev);
 213                 name = udev_device_get_sysname(dev);
 214
 215                 pb_debug("%s: action %s, device %s\n", __func__, action, name);
 216                 pb_debug("%s properties:\n", __func__);
 217
 218                 for (; list; list = udev_list_entry_get_next(list))
 219                         pb_log("\t%-20s: %s\n", udev_list_entry_get_name(list),
 220                                         udev_list_entry_get_value(list));
 221         } while (0);
 222 #endif
 223
 224         if (!strcmp(action, "add"))
 225                 return udev_handle_dev_add(udev, dev);
 226
 227         else if (!strcmp(action, "remove"))
 228                 return udev_handle_dev_remove(udev, dev);
 229
 230         else if (!strcmp(action, "change"))
 231                 return udev_handle_dev_change(udev, dev);
 232
 233         return 0;
 234 }
 235
 236 static int udev_enumerate(struct udev *udev)
 237 {
 238         int result;
 239         struct udev_list_entry *list, *entry;
 240         struct udev_enumerate *enumerate;
 241
 242         enumerate = udev_enumerate_new(udev);
 243
 244         if (!enumerate) {
 245                 pb_log("udev_enumerate_new failed\n");
 246                 return -1;
 247         }
 248
 249         result = udev_enumerate_add_match_subsystem(enumerate, "block");
 250
 251         if (result) {
 252                 pb_log("udev_enumerate_add_match_subsystem failed\n");
 253                 goto fail;
 254         }
 255
 256         udev_enumerate_scan_devices(enumerate);
 257
 258         list = udev_enumerate_get_list_entry(enumerate);
 259
 260         if (!list) {
 261                 pb_log("udev_enumerate_get_list_entry failed\n");
 262                 goto fail;
 263         }
 264
 265         udev_list_entry_foreach(entry, list) {
 266                 const char *syspath;
 267                 struct udev_device *dev;
 268
 269                 syspath = udev_list_entry_get_name(entry);
 270                 dev = udev_device_new_from_syspath(udev, syspath);
 271
 272                 udev_handle_dev_action(dev, "add");
 273
 274                 udev_device_unref(dev);
 275         }
 276
 277         udev_enumerate_unref(enumerate);
 278         return 0;
 279
 280 fail:
 281         udev_enumerate_unref(enumerate);
 282         return -1;
 283 }
 284
 285 static int udev_setup_monitor(struct udev *udev, struct udev_monitor **monitor)
 286 {
 287         int result;
 288         struct udev_monitor *m;
 289
 290         *monitor = NULL;
 291         m = udev_monitor_new_from_netlink(udev, "udev");
 292
 293         if (!m) {
 294                 pb_log("udev_monitor_new_from_netlink failed\n");
 295                 goto out_err;
 296         }
 297
 298         result = udev_monitor_filter_add_match_subsystem_devtype(m, "block",
 299                 NULL);
 300
 301         if (result) {
 302                 pb_log("udev_monitor_filter_add_match_subsystem_devtype failed\n");
 303                 goto out_err;
 304         }
 305
 306         result = udev_monitor_enable_receiving(m);
 307
 308         if (result) {
 309                 pb_log("udev_monitor_enable_receiving failed\n");
 310                 goto out_err;
 311         }
 312
 313         *monitor = m;
 314         return 0;
 315
 316 out_err:
 317         udev_monitor_unref(m);
 318         return -1;
 319 }
 320
 321 /*
 322  * udev_process - waiter callback for monitor netlink.
 323  */
 324
 325 static int udev_process(void *arg)
 326 {
 327         struct udev_monitor *monitor = arg;
 328         struct udev_device *dev;
 329         const char *action;
 330         int result;
 331
 332         dev = udev_monitor_receive_device(monitor);
 333
 334         if (!dev) {
 335                 pb_log("udev_monitor_receive_device failed\n");
 336                 return -1;
 337         }
 338
 339         action = udev_device_get_action(dev);
 340
 341         if (!action) {
 342                 pb_log("udev_device_get_action failed\n");
 343                 goto fail;
 344         }
 345
 346         result = udev_handle_dev_action(dev, action);
 347
 348         udev_device_unref(dev);
 349         return result;
 350
 351 fail:
 352         udev_device_unref(dev);
 353         return -1;
 354 }
 355
 356 static void udev_log_fn(struct udev __attribute__((unused)) *udev,
 357         int __attribute__((unused)) priority, const char *file, int line,
 358         const char *fn, const char *format, va_list args)
 359 {
 360       pb_log("libudev: %s %s:%d: ", fn, file, line);
 361       vfprintf(pb_log_get_stream(), format, args);
 362 }
 363
 364 struct pb_udev *udev_init(struct waitset *waitset,
 365         struct device_handler *handler)
 366 {
 367         int result;
 368         struct pb_udev *udev = talloc(NULL, struct pb_udev);
 369
 370         talloc_set_destructor(udev, udev_destructor);
 371         udev->handler = handler;
 372
 373         udev->udev = udev_new();
 374
 375         if (!udev->udev) {
 376                 pb_log("udev_new failed\n");
 377                 goto fail_new;
 378         }
 379
 380         udev_set_userdata(udev->udev, udev);
 381
 382         udev_set_log_fn(udev->udev, udev_log_fn);
 383
 384         result = udev_enumerate(udev->udev);
 385
 386         if (result)
 387                 goto fail_enumerate;
 388
 389         result = udev_setup_monitor(udev->udev, &udev->monitor);
 390
 391         if (result)
 392                 goto fail_monitor;
 393
 394         waiter_register_io(waitset, udev_monitor_get_fd(udev->monitor), WAIT_IN,
 395                 udev_process, udev->monitor);
 396
 397         pb_debug("%s: waiting on udev\n", __func__);
 398
 399         return udev;
 400
 401 fail_monitor:
 402 fail_enumerate:
 403         udev_unref(udev->udev);
 404 fail_new:
 405         talloc_free(udev);
 406         return NULL;
 407 }
 408
 409 void udev_destroy(struct pb_udev *udev)
 410 {
 411         talloc_free(udev);
 412 }