udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include "config.h"
  21
  22 #include <stddef.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <dirent.h>
  31 #include <fcntl.h>
  32 #include <syslog.h>
  33 #include <time.h>
  34 #include <getopt.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44 #ifdef HAVE_INOTIFY
  45 #include <sys/inotify.h>
  46 #endif
  47
  48 #include "udev.h"
  49 #include "udev_rules.h"
  50 #include "udev_selinux.h"
  51
  52 #define UDEVD_PRIORITY                  -4
  53 #define UDEV_PRIORITY                   -2
  54
  55 /* maximum limit of forked childs */
  56 #define UDEVD_MAX_CHILDS                256
  57
  58 static int debug;
  59
  60 static void log_fn(struct udev *udev, int priority,
  61                    const char *file, int line, const char *fn,
  62                    const char *format, va_list args)
  63 {
  64         if (debug) {
  65                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  66                 vfprintf(stderr, format, args);
  67         } else {
  68                 vsyslog(priority, format, args);
  69         }
  70 }
  71
  72 struct udevd_uevent_msg {
  73         struct udev *udev;
  74         struct list_head node;
  75         pid_t pid;
  76         int exitstatus;
  77         time_t queue_time;
  78         char *action;
  79         char *devpath;
  80         char *subsystem;
  81         char *driver;
  82         dev_t devt;
  83         unsigned long long seqnum;
  84         char *devpath_old;
  85         char *physdevpath;
  86         unsigned int timeout;
  87         char *envp[UEVENT_NUM_ENVP+1];
  88         char envbuf[];
  89 };
  90
  91 static int debug_trace;
  92 static struct udev_rules rules;
  93 static struct udev_ctrl *udev_ctrl;
  94 static int uevent_netlink_sock = -1;
  95 static int inotify_fd = -1;
  96
  97 static int signal_pipe[2] = {-1, -1};
  98 static volatile int sigchilds_waiting;
  99 static volatile int udev_exit;
 100 static volatile int reload_config;
 101 static int run_exec_q;
 102 static int stop_exec_q;
 103 static int max_childs;
 104 static char udev_log_env[32];
 105
 106 static LIST_HEAD(exec_list);
 107 static LIST_HEAD(running_list);
 108
 109 static void asmlinkage udev_event_sig_handler(int signum)
 110 {
 111         if (signum == SIGALRM)
 112                 exit(1);
 113 }
 114
 115 static int udev_event_process(struct udevd_uevent_msg *msg)
 116 {
 117         struct sigaction act;
 118         struct udevice *udevice;
 119         int i;
 120         int retval;
 121
 122         /* set signal handlers */
 123         memset(&act, 0x00, sizeof(act));
 124         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 125         sigemptyset (&act.sa_mask);
 126         act.sa_flags = 0;
 127         sigaction(SIGALRM, &act, NULL);
 128
 129         /* reset to default */
 130         act.sa_handler = SIG_DFL;
 131         sigaction(SIGINT, &act, NULL);
 132         sigaction(SIGTERM, &act, NULL);
 133         sigaction(SIGCHLD, &act, NULL);
 134         sigaction(SIGHUP, &act, NULL);
 135
 136         /* trigger timeout to prevent hanging processes */
 137         alarm(UDEV_EVENT_TIMEOUT);
 138
 139         /* reconstruct event environment from message */
 140         for (i = 0; msg->envp[i]; i++)
 141                 putenv(msg->envp[i]);
 142
 143         udevice = udev_device_init(msg->udev);
 144         if (udevice == NULL)
 145                 return -1;
 146         strlcpy(udevice->action, msg->action, sizeof(udevice->action));
 147         sysfs_device_set_values(udevice->udev, udevice->dev, msg->devpath, msg->subsystem, msg->driver);
 148         udevice->devpath_old = msg->devpath_old;
 149         udevice->devt = msg->devt;
 150
 151         retval = udev_device_event(&rules, udevice);
 152
 153         /* rules may change/disable the timeout */
 154         if (udevice->event_timeout >= 0)
 155                 alarm(udevice->event_timeout);
 156
 157         /* run programs collected by RUN-key*/
 158         if (retval == 0 && !udevice->ignore_device && udev_get_run(msg->udev))
 159                 retval = udev_rules_run(udevice);
 160
 161         udev_device_cleanup(udevice);
 162         return retval;
 163 }
 164
 165 enum event_state {
 166         EVENT_QUEUED,
 167         EVENT_FINISHED,
 168         EVENT_FAILED,
 169 };
 170
 171 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 172 {
 173         char filename[PATH_SIZE];
 174         char filename_failed[PATH_SIZE];
 175         size_t start;
 176
 177         /* location of queue file */
 178         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu", udev_get_dev_path(msg->udev), msg->seqnum);
 179
 180         /* location of failed file */
 181         strlcpy(filename_failed, udev_get_dev_path(msg->udev), sizeof(filename_failed));
 182         strlcat(filename_failed, "/", sizeof(filename_failed));
 183         start = strlcat(filename_failed, ".udev/failed/", sizeof(filename_failed));
 184         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 185         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 186
 187         switch (state) {
 188         case EVENT_QUEUED:
 189                 unlink(filename_failed);
 190                 delete_path(msg->udev, filename_failed);
 191                 create_path(msg->udev, filename);
 192                 selinux_setfscreatecon(msg->udev, filename, NULL, S_IFLNK);
 193                 symlink(msg->devpath, filename);
 194                 selinux_resetfscreatecon(msg->udev);
 195                 break;
 196         case EVENT_FINISHED:
 197                 if (msg->devpath_old != NULL) {
 198                         /* "move" event - rename failed file to current name, do not delete failed */
 199                         char filename_failed_old[PATH_SIZE];
 200
 201                         strlcpy(filename_failed_old, udev_get_dev_path(msg->udev), sizeof(filename_failed_old));
 202                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 203                         start = strlcat(filename_failed_old, ".udev/failed/", sizeof(filename_failed_old));
 204                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 205                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 206
 207                         if (rename(filename_failed_old, filename_failed) == 0)
 208                                 info(msg->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 209                                      msg->devpath_old, msg->devpath);
 210                 } else {
 211                         unlink(filename_failed);
 212                         delete_path(msg->udev, filename_failed);
 213                 }
 214
 215                 unlink(filename);
 216                 delete_path(msg->udev, filename);
 217                 break;
 218         case EVENT_FAILED:
 219                 /* move failed event to the failed directory */
 220                 create_path(msg->udev, filename_failed);
 221                 rename(filename, filename_failed);
 222
 223                 /* clean up possibly empty queue directory */
 224                 delete_path(msg->udev, filename);
 225                 break;
 226         }
 227
 228         return;
 229 }
 230
 231 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 232 {
 233         list_del(&msg->node);
 234
 235         /* mark as failed, if "add" event returns non-zero */
 236         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 237                 export_event_state(msg, EVENT_FAILED);
 238         else
 239                 export_event_state(msg, EVENT_FINISHED);
 240
 241         free(msg);
 242 }
 243
 244 static void udev_event_run(struct udevd_uevent_msg *msg)
 245 {
 246         pid_t pid;
 247         int retval;
 248
 249         pid = fork();
 250         switch (pid) {
 251         case 0:
 252                 /* child */
 253                 close(uevent_netlink_sock);
 254                 udev_ctrl_unref(udev_ctrl);
 255                 if (inotify_fd >= 0)
 256                         close(inotify_fd);
 257                 close(signal_pipe[READ_END]);
 258                 close(signal_pipe[WRITE_END]);
 259                 logging_close();
 260                 logging_init("udevd-event");
 261                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 262
 263                 retval = udev_event_process(msg);
 264                 info(msg->udev, "seq %llu finished with %i\n", msg->seqnum, retval);
 265
 266                 logging_close();
 267                 if (retval)
 268                         exit(1);
 269                 exit(0);
 270         case -1:
 271                 err(msg->udev, "fork of child failed: %s\n", strerror(errno));
 272                 msg_queue_delete(msg);
 273                 break;
 274         default:
 275                 /* get SIGCHLD in main loop */
 276                 info(msg->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 277                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 278                 msg->pid = pid;
 279         }
 280 }
 281
 282 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 283 {
 284         char filename[PATH_SIZE];
 285         int fd;
 286
 287         msg->queue_time = time(NULL);
 288
 289         export_event_state(msg, EVENT_QUEUED);
 290         info(msg->udev, "seq %llu queued, '%s' '%s'\n", msg->seqnum, msg->action, msg->subsystem);
 291
 292         strlcpy(filename, udev_get_dev_path(msg->udev), sizeof(filename));
 293         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 294         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 295         if (fd >= 0) {
 296                 char str[32];
 297                 int len;
 298
 299                 len = sprintf(str, "%llu\n", msg->seqnum);
 300                 write(fd, str, len);
 301                 close(fd);
 302         }
 303
 304         /* run one event after the other in debug mode */
 305         if (debug_trace) {
 306                 list_add_tail(&msg->node, &running_list);
 307                 udev_event_run(msg);
 308                 waitpid(msg->pid, NULL, 0);
 309                 msg_queue_delete(msg);
 310                 return;
 311         }
 312
 313         /* run all events with a timeout set immediately */
 314         if (msg->timeout != 0) {
 315                 list_add_tail(&msg->node, &running_list);
 316                 udev_event_run(msg);
 317                 return;
 318         }
 319
 320         list_add_tail(&msg->node, &exec_list);
 321         run_exec_q = 1;
 322 }
 323
 324 static int mem_size_mb(void)
 325 {
 326         FILE* f;
 327         char buf[4096];
 328         long int memsize = -1;
 329
 330         f = fopen("/proc/meminfo", "r");
 331         if (f == NULL)
 332                 return -1;
 333
 334         while (fgets(buf, sizeof(buf), f) != NULL) {
 335                 long int value;
 336
 337                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 338                         memsize = value / 1024;
 339                         break;
 340                 }
 341         }
 342
 343         fclose(f);
 344         return memsize;
 345 }
 346
 347 static int compare_devpath(const char *running, const char *waiting)
 348 {
 349         int i;
 350
 351         for (i = 0; i < PATH_SIZE; i++) {
 352                 /* identical device event found */
 353                 if (running[i] == '\0' && waiting[i] == '\0')
 354                         return 1;
 355
 356                 /* parent device event found */
 357                 if (running[i] == '\0' && waiting[i] == '/')
 358                         return 2;
 359
 360                 /* child device event found */
 361                 if (running[i] == '/' && waiting[i] == '\0')
 362                         return 3;
 363
 364                 /* no matching event */
 365                 if (running[i] != waiting[i])
 366                         break;
 367         }
 368
 369         return 0;
 370 }
 371
 372 /* lookup event for identical, parent, child, or physical device */
 373 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 374 {
 375         struct udevd_uevent_msg *loop_msg;
 376         int childs_count = 0;
 377
 378         /* check exec-queue which may still contain delayed events we depend on */
 379         list_for_each_entry(loop_msg, &exec_list, node) {
 380                 /* skip ourself and all later events */
 381                 if (loop_msg->seqnum >= msg->seqnum)
 382                         break;
 383
 384                 /* check our old name */
 385                 if (msg->devpath_old != NULL)
 386                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 387                                 return 2;
 388
 389                 /* check identical, parent, or child device event */
 390                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 391                         dbg(msg->udev, "%llu, device event still pending %llu (%s)\n",
 392                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 393                         return 3;
 394                 }
 395
 396                 /* check for our major:minor number */
 397                 if (msg->devt && loop_msg->devt == msg->devt &&
 398                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 399                         dbg(msg->udev, "%llu, device event still pending %llu (%d:%d)\n", msg->seqnum,
 400                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 401                         return 4;
 402                 }
 403
 404                 /* check physical device event (special case of parent) */
 405                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 406                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 407                                 dbg(msg->udev, "%llu, physical device event still pending %llu (%s)\n",
 408                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 409                                 return 5;
 410                         }
 411         }
 412
 413         /* check run queue for still running events */
 414         list_for_each_entry(loop_msg, &running_list, node) {
 415                 childs_count++;
 416
 417                 if (childs_count++ >= limit) {
 418                         info(msg->udev, "%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 419                         return 1;
 420                 }
 421
 422                 /* check our old name */
 423                 if (msg->devpath_old != NULL)
 424                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 425                                 return 2;
 426
 427                 /* check identical, parent, or child device event */
 428                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 429                         dbg(msg->udev, "%llu, device event still running %llu (%s)\n",
 430                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 431                         return 3;
 432                 }
 433
 434                 /* check for our major:minor number */
 435                 if (msg->devt && loop_msg->devt == msg->devt &&
 436                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 437                         dbg(msg->udev, "%llu, device event still running %llu (%d:%d)\n", msg->seqnum,
 438                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 439                         return 4;
 440                 }
 441
 442                 /* check physical device event (special case of parent) */
 443                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 444                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 445                                 dbg(msg->udev, "%llu, physical device event still running %llu (%s)\n",
 446                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 447                                 return 5;
 448                         }
 449         }
 450         return 0;
 451 }
 452
 453 /* serializes events for the identical and parent and child devices */
 454 static void msg_queue_manager(struct udev *udev)
 455 {
 456         struct udevd_uevent_msg *loop_msg;
 457         struct udevd_uevent_msg *tmp_msg;
 458
 459         if (list_empty(&exec_list))
 460                 return;
 461
 462         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 463                 /* serialize and wait for parent or child events */
 464                 if (devpath_busy(loop_msg, max_childs) != 0) {
 465                         dbg(udev, "delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
 466                         continue;
 467                 }
 468
 469                 /* move event to run list */
 470                 list_move_tail(&loop_msg->node, &running_list);
 471                 udev_event_run(loop_msg);
 472                 dbg(udev, "moved seq %llu to running list\n", loop_msg->seqnum);
 473         }
 474 }
 475
 476 static struct udevd_uevent_msg *get_msg_from_envbuf(struct udev *udev, const char *buf, int buf_size)
 477 {
 478         int bufpos;
 479         int i;
 480         struct udevd_uevent_msg *msg;
 481         char *physdevdriver_key = NULL;
 482         int maj = 0;
 483         int min = 0;
 484
 485         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 486         if (msg == NULL)
 487                 return NULL;
 488         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 489         msg->udev = udev;
 490
 491         /* copy environment buffer and reconstruct envp */
 492         memcpy(msg->envbuf, buf, buf_size);
 493         bufpos = 0;
 494         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 495                 int keylen;
 496                 char *key;
 497
 498                 key = &msg->envbuf[bufpos];
 499                 keylen = strlen(key);
 500                 msg->envp[i] = key;
 501                 bufpos += keylen + 1;
 502                 dbg(udev, "add '%s' to msg.envp[%i]\n", msg->envp[i], i);
 503
 504                 /* remember some keys for further processing */
 505                 if (strncmp(key, "ACTION=", 7) == 0)
 506                         msg->action = &key[7];
 507                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 508                         msg->devpath = &key[8];
 509                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 510                         msg->subsystem = &key[10];
 511                 else if (strncmp(key, "DRIVER=", 7) == 0)
 512                         msg->driver = &key[7];
 513                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 514                         msg->seqnum = strtoull(&key[7], NULL, 10);
 515                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 516                         msg->devpath_old = &key[12];
 517                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 518                         msg->physdevpath = &key[12];
 519                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 520                         physdevdriver_key = key;
 521                 else if (strncmp(key, "MAJOR=", 6) == 0)
 522                         maj = strtoull(&key[6], NULL, 10);
 523                 else if (strncmp(key, "MINOR=", 6) == 0)
 524                         min = strtoull(&key[6], NULL, 10);
 525                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 526                         msg->timeout = strtoull(&key[8], NULL, 10);
 527         }
 528         msg->devt = makedev(maj, min);
 529         msg->envp[i++] = "UDEVD_EVENT=1";
 530
 531         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 532                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 533                 msg->envp[i++] = &physdevdriver_key[7];
 534                 msg->driver = &physdevdriver_key[14];
 535         }
 536
 537         msg->envp[i] = NULL;
 538
 539         if (msg->devpath == NULL || msg->action == NULL) {
 540                 info(udev, "DEVPATH or ACTION missing, ignore message\n");
 541                 free(msg);
 542                 return NULL;
 543         }
 544         return msg;
 545 }
 546
 547 /* receive the udevd message from userspace */
 548 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 549 {
 550         struct udev *udev = udev_ctrl_get_udev(uctrl);
 551         struct udev_ctrl_msg *ctrl_msg;
 552         const char *str;
 553         int i;
 554
 555         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 556         if (ctrl_msg == NULL)
 557                 return;
 558
 559         i = udev_ctrl_get_set_log_level(ctrl_msg);
 560         if (i >= 0) {
 561                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 562                 udev_set_log_priority(udev, i);
 563                 sprintf(udev_log_env, "UDEV_LOG=%i", i);
 564                 putenv(udev_log_env);
 565         }
 566
 567         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 568                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 569                 stop_exec_q = 1;
 570         }
 571
 572         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 573                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 574                 stop_exec_q = 0;
 575                 msg_queue_manager(udev);
 576         }
 577
 578         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 579                 info(udev, "udevd message (RELOAD_RULES) received\n");
 580                 reload_config = 1;
 581         }
 582
 583         str = udev_ctrl_get_set_env(ctrl_msg);
 584         if (str != NULL) {
 585                 char *key = strdup(str);
 586                 char *val;
 587
 588                 val = strchr(str, '=');
 589                 if (val != NULL) {
 590                         val[0] = '\0';
 591                         val = &val[1];
 592                         if (val[0] == '\0') {
 593                                 info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 594                                 unsetenv(str);
 595                         } else {
 596                                 info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 597                                 setenv(key, val, 1);
 598                         }
 599                 } else {
 600                         err(udev, "wrong key format '%s'\n", key);
 601                 }
 602                 free(key);
 603         }
 604
 605         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 606         if (i >= 0) {
 607                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 608                 max_childs = i;
 609         }
 610
 611         udev_ctrl_msg_unref(ctrl_msg);
 612 }
 613
 614 /* receive the kernel user event message and do some sanity checks */
 615 static struct udevd_uevent_msg *get_netlink_msg(struct udev *udev)
 616 {
 617         struct udevd_uevent_msg *msg;
 618         int bufpos;
 619         ssize_t size;
 620         static char buffer[UEVENT_BUFFER_SIZE+512];
 621         char *pos;
 622
 623         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 624         if (size <  0) {
 625                 if (errno != EINTR)
 626                         err(udev, "unable to receive kernel netlink message: %s\n", strerror(errno));
 627                 return NULL;
 628         }
 629
 630         if ((size_t)size > sizeof(buffer)-1)
 631                 size = sizeof(buffer)-1;
 632         buffer[size] = '\0';
 633         dbg(udev, "uevent_size=%zi\n", size);
 634
 635         /* start of event payload */
 636         bufpos = strlen(buffer)+1;
 637         msg = get_msg_from_envbuf(udev, &buffer[bufpos], size-bufpos);
 638         if (msg == NULL)
 639                 return NULL;
 640
 641         /* validate message */
 642         pos = strchr(buffer, '@');
 643         if (pos == NULL) {
 644                 err(udev, "invalid uevent '%s'\n", buffer);
 645                 free(msg);
 646                 return NULL;
 647         }
 648         pos[0] = '\0';
 649
 650         if (msg->action == NULL) {
 651                 info(udev, "no ACTION in payload found, skip event '%s'\n", buffer);
 652                 free(msg);
 653                 return NULL;
 654         }
 655
 656         if (strcmp(msg->action, buffer) != 0) {
 657                 err(udev, "ACTION in payload does not match uevent, skip event '%s'\n", buffer);
 658                 free(msg);
 659                 return NULL;
 660         }
 661
 662         return msg;
 663 }
 664
 665 static void asmlinkage sig_handler(int signum)
 666 {
 667         switch (signum) {
 668                 case SIGINT:
 669                 case SIGTERM:
 670                         udev_exit = 1;
 671                         break;
 672                 case SIGCHLD:
 673                         /* set flag, then write to pipe if needed */
 674                         sigchilds_waiting = 1;
 675                         break;
 676                 case SIGHUP:
 677                         reload_config = 1;
 678                         break;
 679         }
 680
 681         /* write to pipe, which will wakeup select() in our mainloop */
 682         write(signal_pipe[WRITE_END], "", 1);
 683 }
 684
 685 static void udev_done(int pid, int exitstatus)
 686 {
 687         /* find msg associated with pid and delete it */
 688         struct udevd_uevent_msg *msg;
 689
 690         list_for_each_entry(msg, &running_list, node) {
 691                 if (msg->pid == pid) {
 692                         info(msg->udev, "seq %llu, pid [%d] exit with %i, %ld seconds old\n", msg->seqnum, msg->pid,
 693                              exitstatus, time(NULL) - msg->queue_time);
 694                         msg->exitstatus = exitstatus;
 695                         msg_queue_delete(msg);
 696
 697                         /* there may be events waiting with the same devpath */
 698                         run_exec_q = 1;
 699                         return;
 700                 }
 701         }
 702 }
 703
 704 static void reap_sigchilds(void)
 705 {
 706         pid_t pid;
 707         int status;
 708
 709         while (1) {
 710                 pid = waitpid(-1, &status, WNOHANG);
 711                 if (pid <= 0)
 712                         break;
 713                 if (WIFEXITED(status))
 714                         status = WEXITSTATUS(status);
 715                 else if (WIFSIGNALED(status))
 716                         status = WTERMSIG(status) + 128;
 717                 else
 718                         status = 0;
 719                 udev_done(pid, status);
 720         }
 721 }
 722
 723 static int init_uevent_netlink_sock(struct udev *udev)
 724 {
 725         struct sockaddr_nl snl;
 726         const int buffersize = 16 * 1024 * 1024;
 727         int retval;
 728
 729         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 730         snl.nl_family = AF_NETLINK;
 731         snl.nl_pid = getpid();
 732         snl.nl_groups = 1;
 733
 734         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 735         if (uevent_netlink_sock == -1) {
 736                 err(udev, "error getting socket: %s\n", strerror(errno));
 737                 return -1;
 738         }
 739
 740         /* set receive buffersize */
 741         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 742
 743         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 744         if (retval < 0) {
 745                 err(udev, "bind failed: %s\n", strerror(errno));
 746                 close(uevent_netlink_sock);
 747                 uevent_netlink_sock = -1;
 748                 return -1;
 749         }
 750         return 0;
 751 }
 752
 753 static void export_initial_seqnum(struct udev *udev)
 754 {
 755         char filename[PATH_SIZE];
 756         int fd;
 757         char seqnum[32];
 758         ssize_t len = 0;
 759
 760         strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 761         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 762         fd = open(filename, O_RDONLY);
 763         if (fd >= 0) {
 764                 len = read(fd, seqnum, sizeof(seqnum)-1);
 765                 close(fd);
 766         }
 767         if (len <= 0) {
 768                 strcpy(seqnum, "0\n");
 769                 len = 3;
 770         }
 771         strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 772         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 773         create_path(udev, filename);
 774         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 775         if (fd >= 0) {
 776                 write(fd, seqnum, len);
 777                 close(fd);
 778         }
 779 }
 780
 781 int main(int argc, char *argv[])
 782 {
 783         struct udev *udev;
 784         int retval;
 785         int fd;
 786         struct sigaction act;
 787         fd_set readfds;
 788         const char *value;
 789         int daemonize = 0;
 790         static const struct option options[] = {
 791                 { "daemon", 0, NULL, 'd' },
 792                 { "debug-trace", 0, NULL, 't' },
 793                 { "debug", 0, NULL, 'D' },
 794                 { "help", 0, NULL, 'h' },
 795                 { "version", 0, NULL, 'V' },
 796                 {}
 797         };
 798         int rc = 1;
 799         int maxfd;
 800
 801         udev = udev_new();
 802         if (udev == NULL)
 803                 goto exit;
 804
 805         logging_init("udevd");
 806         udev_set_log_fn(udev, log_fn);
 807
 808         selinux_init(udev);
 809         dbg(udev, "version %s\n", VERSION);
 810
 811         while (1) {
 812                 int option;
 813
 814                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 815                 if (option == -1)
 816                         break;
 817
 818                 switch (option) {
 819                 case 'd':
 820                         daemonize = 1;
 821                         break;
 822                 case 't':
 823                         debug_trace = 1;
 824                         break;
 825                 case 'D':
 826                         debug = 1;
 827                         if (udev_get_log_priority(udev) < LOG_INFO)
 828                                 udev_set_log_priority(udev, LOG_INFO);
 829                         break;
 830                 case 'h':
 831                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
 832                         goto exit;
 833                 case 'V':
 834                         printf("%s\n", VERSION);
 835                         goto exit;
 836                 default:
 837                         goto exit;
 838                 }
 839         }
 840
 841         if (getuid() != 0) {
 842                 fprintf(stderr, "root privileges required\n");
 843                 err(udev, "root privileges required\n");
 844                 goto exit;
 845         }
 846
 847         /* make sure std{in,out,err} fd's are in a sane state */
 848         fd = open("/dev/null", O_RDWR);
 849         if (fd < 0) {
 850                 fprintf(stderr, "cannot open /dev/null\n");
 851                 err(udev, "cannot open /dev/null\n");
 852         }
 853         if (fd > STDIN_FILENO)
 854                 dup2(fd, STDIN_FILENO);
 855         if (write(STDOUT_FILENO, 0, 0) < 0)
 856                 dup2(fd, STDOUT_FILENO);
 857         if (write(STDERR_FILENO, 0, 0) < 0)
 858                 dup2(fd, STDERR_FILENO);
 859
 860         /* init control socket, bind() ensures, that only one udevd instance is running */
 861         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 862         if (udev_ctrl == NULL) {
 863                 fprintf(stderr, "error initializing control socket");
 864                 err(udev, "error initializing udevd socket");
 865                 rc = 1;
 866                 goto exit;
 867         }
 868
 869         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 870                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 871                 err(udev, "error binding control socket, seems udevd is already running\n");
 872                 rc = 1;
 873                 goto exit;
 874         }
 875
 876         if (init_uevent_netlink_sock(udev) < 0) {
 877                 fprintf(stderr, "error initializing netlink socket\n");
 878                 err(udev, "error initializing netlink socket\n");
 879                 rc = 3;
 880                 goto exit;
 881         }
 882
 883         retval = pipe(signal_pipe);
 884         if (retval < 0) {
 885                 err(udev, "error getting pipes: %s\n", strerror(errno));
 886                 goto exit;
 887         }
 888
 889         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 890         if (retval < 0) {
 891                 err(udev, "error fcntl on read pipe: %s\n", strerror(errno));
 892                 goto exit;
 893         }
 894         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 895         if (retval < 0) {
 896                 err(udev, "error fcntl on read pipe: %s\n", strerror(errno));
 897                 goto exit;
 898         }
 899
 900         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 901         if (retval < 0) {
 902                 err(udev, "error fcntl on write pipe: %s\n", strerror(errno));
 903                 goto exit;
 904         }
 905         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 906         if (retval < 0) {
 907                 err(udev, "error fcntl on write pipe: %s\n", strerror(errno));
 908                 goto exit;
 909         }
 910
 911         /* parse the rules and keep them in memory */
 912         sysfs_init();
 913         udev_rules_init(udev, &rules, 1);
 914
 915         export_initial_seqnum(udev);
 916
 917         if (daemonize) {
 918                 pid_t pid;
 919
 920                 pid = fork();
 921                 switch (pid) {
 922                 case 0:
 923                         dbg(udev, "daemonized fork running\n");
 924                         break;
 925                 case -1:
 926                         err(udev, "fork of daemon failed: %s\n", strerror(errno));
 927                         rc = 4;
 928                         goto exit;
 929                 default:
 930                         dbg(udev, "child [%u] running, parent exits\n", pid);
 931                         rc = 0;
 932                         goto exit;
 933                 }
 934         }
 935
 936         /* redirect std{out,err} */
 937         if (!debug) {
 938                 dup2(fd, STDOUT_FILENO);
 939                 dup2(fd, STDERR_FILENO);
 940         }
 941         if (fd > STDERR_FILENO)
 942                 close(fd);
 943
 944         /* set scheduling priority for the daemon */
 945         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 946
 947         chdir("/");
 948         umask(022);
 949         setsid();
 950
 951         /* OOM_DISABLE == -17 */
 952         fd = open("/proc/self/oom_adj", O_RDWR);
 953         if (fd < 0)
 954                 err(udev, "error disabling OOM: %s\n", strerror(errno));
 955         else {
 956                 write(fd, "-17", 3);
 957                 close(fd);
 958         }
 959
 960         fd = open("/dev/kmsg", O_WRONLY);
 961         if (fd > 0) {
 962                 const char *str = "<6>udevd version " VERSION " started\n";
 963
 964                 write(fd, str, strlen(str));
 965                 close(fd);
 966         }
 967
 968         /* set signal handlers */
 969         memset(&act, 0x00, sizeof(struct sigaction));
 970         act.sa_handler = (void (*)(int)) sig_handler;
 971         sigemptyset(&act.sa_mask);
 972         act.sa_flags = SA_RESTART;
 973         sigaction(SIGINT, &act, NULL);
 974         sigaction(SIGTERM, &act, NULL);
 975         sigaction(SIGCHLD, &act, NULL);
 976         sigaction(SIGHUP, &act, NULL);
 977
 978         /* watch rules directory */
 979         inotify_fd = inotify_init();
 980         if (inotify_fd >= 0) {
 981                 if (udev_get_rules_path(udev) != NULL) {
 982                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 983                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 984                 } else {
 985                         char filename[PATH_MAX];
 986
 987                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 988                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 989                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 990                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 991
 992                         /* watch dynamic rules directory */
 993                         strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 994                         strlcat(filename, "/.udev/rules.d", sizeof(filename));
 995                         inotify_add_watch(inotify_fd, filename,
 996                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 997                 }
 998         } else if (errno == ENOSYS)
 999                 err(udev, "the kernel does not support inotify, udevd can't monitor rules file changes\n");
1000         else
1001                 err(udev, "inotify_init failed: %s\n", strerror(errno));
1002
1003         /* maximum limit of forked childs */
1004         value = getenv("UDEVD_MAX_CHILDS");
1005         if (value)
1006                 max_childs = strtoul(value, NULL, 10);
1007         else {
1008                 int memsize = mem_size_mb();
1009                 if (memsize > 0)
1010                         max_childs = 128 + (memsize / 4);
1011                 else
1012                         max_childs = UDEVD_MAX_CHILDS;
1013         }
1014         info(udev, "initialize max_childs to %u\n", max_childs);
1015
1016         /* clear environment for forked event processes */
1017         clearenv();
1018
1019         /* export log_priority , as called programs may want to follow that setting */
1020         sprintf(udev_log_env, "UDEV_LOG=%i", udev_get_log_priority(udev));
1021         putenv(udev_log_env);
1022         if (debug_trace)
1023                 putenv("DEBUG=1");
1024
1025         maxfd = udev_ctrl_get_fd(udev_ctrl);
1026         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1027         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1028         maxfd = UDEV_MAX(maxfd, inotify_fd);
1029
1030         while (!udev_exit) {
1031                 struct udevd_uevent_msg *msg;
1032                 int fdcount;
1033
1034                 FD_ZERO(&readfds);
1035                 FD_SET(signal_pipe[READ_END], &readfds);
1036                 FD_SET(udev_ctrl_get_fd(udev_ctrl), &readfds);
1037                 FD_SET(uevent_netlink_sock, &readfds);
1038                 if (inotify_fd >= 0)
1039                         FD_SET(inotify_fd, &readfds);
1040
1041                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1042                 if (fdcount < 0) {
1043                         if (errno != EINTR)
1044                                 err(udev, "error in select: %s\n", strerror(errno));
1045                         continue;
1046                 }
1047
1048                 /* get control message */
1049                 if (FD_ISSET(udev_ctrl_get_fd(udev_ctrl), &readfds))
1050                         handle_ctrl_msg(udev_ctrl);
1051
1052                 /* get netlink message */
1053                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1054                         msg = get_netlink_msg(udev);
1055                         if (msg)
1056                                 msg_queue_insert(msg);
1057                 }
1058
1059                 /* received a signal, clear our notification pipe */
1060                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1061                         char buf[256];
1062
1063                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1064                 }
1065
1066                 /* rules directory inotify watch */
1067                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1068                         int nbytes;
1069
1070                         /* discard all possible events, we can just reload the config */
1071                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1072                                 char *buf;
1073
1074                                 reload_config = 1;
1075                                 buf = malloc(nbytes);
1076                                 if (buf == NULL) {
1077                                         err(udev, "error getting buffer for inotify, disable watching\n");
1078                                         close(inotify_fd);
1079                                         inotify_fd = -1;
1080                                 }
1081                                 read(inotify_fd, buf, nbytes);
1082                                 free(buf);
1083                         }
1084                 }
1085
1086                 /* rules changed, set by inotify or a HUP signal */
1087                 if (reload_config) {
1088                         reload_config = 0;
1089                         udev_rules_cleanup(&rules);
1090                         udev_rules_init(udev, &rules, 1);
1091                 }
1092
1093                 /* forked child has returned */
1094                 if (sigchilds_waiting) {
1095                         sigchilds_waiting = 0;
1096                         reap_sigchilds();
1097                 }
1098
1099                 if (run_exec_q) {
1100                         run_exec_q = 0;
1101                         if (!stop_exec_q)
1102                                 msg_queue_manager(udev);
1103                 }
1104         }
1105         rc = 0;
1106
1107 exit:
1108         udev_rules_cleanup(&rules);
1109         sysfs_cleanup();
1110         selinux_exit(udev);
1111
1112         if (signal_pipe[READ_END] >= 0)
1113                 close(signal_pipe[READ_END]);
1114         if (signal_pipe[WRITE_END] >= 0)
1115                 close(signal_pipe[WRITE_END]);
1116
1117         udev_ctrl_unref(udev_ctrl);
1118         if (inotify_fd >= 0)
1119                 close(inotify_fd);
1120         if (uevent_netlink_sock >= 0)
1121                 close(uevent_netlink_sock);
1122
1123         logging_close();
1124         return rc;
1125 }