udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2008 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
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "config.h"
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <dirent.h>
  30 #include <fcntl.h>
  31 #include <syslog.h>
  32 #include <time.h>
  33 #include <getopt.h>
  34 #include <sys/select.h>
  35 #include <sys/wait.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38 #include <sys/un.h>
  39 #include <sys/stat.h>
  40 #include <sys/ioctl.h>
  41 #include <linux/types.h>
  42 #include <linux/netlink.h>
  43 #ifdef HAVE_INOTIFY
  44 #include <sys/inotify.h>
  45 #endif
  46
  47 #include "udev.h"
  48 #include "udev_rules.h"
  49
  50 #define UDEVD_PRIORITY                  -4
  51 #define UDEV_PRIORITY                   -2
  52
  53 /* maximum limit of forked childs */
  54 #define UDEVD_MAX_CHILDS                256
  55
  56 static int debug;
  57
  58 static void log_fn(struct udev *udev, int priority,
  59                    const char *file, int line, const char *fn,
  60                    const char *format, va_list args)
  61 {
  62         if (debug) {
  63                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  64                 vfprintf(stderr, format, args);
  65         } else {
  66                 vsyslog(priority, format, args);
  67         }
  68 }
  69
  70 struct udevd_uevent_msg {
  71         struct udev *udev;
  72         struct list_head node;
  73         pid_t pid;
  74         int exitstatus;
  75         time_t queue_time;
  76         char *action;
  77         char *devpath;
  78         char *subsystem;
  79         char *driver;
  80         dev_t devt;
  81         unsigned long long seqnum;
  82         char *devpath_old;
  83         char *physdevpath;
  84         unsigned int timeout;
  85         char *envp[UEVENT_NUM_ENVP+1];
  86         char envbuf[];
  87 };
  88
  89 static int debug_trace;
  90 static struct udev_rules rules;
  91 static struct udev_ctrl *udev_ctrl;
  92 static int uevent_netlink_sock = -1;
  93 static int inotify_fd = -1;
  94
  95 static int signal_pipe[2] = {-1, -1};
  96 static volatile int sigchilds_waiting;
  97 static volatile int udev_exit;
  98 static volatile int reload_config;
  99 static int run_exec_q;
 100 static int stop_exec_q;
 101 static int max_childs;
 102 static char udev_log_env[32];
 103
 104 static LIST_HEAD(exec_list);
 105 static LIST_HEAD(running_list);
 106
 107 static void asmlinkage udev_event_sig_handler(int signum)
 108 {
 109         if (signum == SIGALRM)
 110                 exit(1);
 111 }
 112
 113 static int udev_event_process(struct udevd_uevent_msg *msg)
 114 {
 115         struct sigaction act;
 116         struct udevice *udevice;
 117         int i;
 118         int retval;
 119
 120         /* set signal handlers */
 121         memset(&act, 0x00, sizeof(act));
 122         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 123         sigemptyset (&act.sa_mask);
 124         act.sa_flags = 0;
 125         sigaction(SIGALRM, &act, NULL);
 126
 127         /* reset to default */
 128         act.sa_handler = SIG_DFL;
 129         sigaction(SIGINT, &act, NULL);
 130         sigaction(SIGTERM, &act, NULL);
 131         sigaction(SIGCHLD, &act, NULL);
 132         sigaction(SIGHUP, &act, NULL);
 133
 134         /* trigger timeout to prevent hanging processes */
 135         alarm(UDEV_EVENT_TIMEOUT);
 136
 137         /* reconstruct event environment from message */
 138         for (i = 0; msg->envp[i]; i++)
 139                 putenv(msg->envp[i]);
 140
 141         udevice = udev_device_init(msg->udev);
 142         if (udevice == NULL)
 143                 return -1;
 144         strlcpy(udevice->action, msg->action, sizeof(udevice->action));
 145         sysfs_device_set_values(udevice->udev, udevice->dev, msg->devpath, msg->subsystem, msg->driver);
 146         udevice->devpath_old = msg->devpath_old;
 147         udevice->devt = msg->devt;
 148
 149         retval = udev_device_event(&rules, udevice);
 150
 151         /* rules may change/disable the timeout */
 152         if (udevice->event_timeout >= 0)
 153                 alarm(udevice->event_timeout);
 154
 155         /* run programs collected by RUN-key*/
 156         if (retval == 0 && !udevice->ignore_device && udev_get_run(msg->udev))
 157                 retval = udev_rules_run(udevice);
 158
 159         udev_device_cleanup(udevice);
 160         return retval;
 161 }
 162
 163 enum event_state {
 164         EVENT_QUEUED,
 165         EVENT_FINISHED,
 166         EVENT_FAILED,
 167 };
 168
 169 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 170 {
 171         char filename[PATH_SIZE];
 172         char filename_failed[PATH_SIZE];
 173         size_t start;
 174
 175         /* location of queue file */
 176         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu", udev_get_dev_path(msg->udev), msg->seqnum);
 177
 178         /* location of failed file */
 179         strlcpy(filename_failed, udev_get_dev_path(msg->udev), sizeof(filename_failed));
 180         strlcat(filename_failed, "/", sizeof(filename_failed));
 181         start = strlcat(filename_failed, ".udev/failed/", sizeof(filename_failed));
 182         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 183         util_path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 184
 185         switch (state) {
 186         case EVENT_QUEUED:
 187                 unlink(filename_failed);
 188                 delete_path(msg->udev, filename_failed);
 189                 create_path(msg->udev, filename);
 190                 udev_selinux_setfscreatecon(msg->udev, filename, S_IFLNK);
 191                 symlink(msg->devpath, filename);
 192                 udev_selinux_resetfscreatecon(msg->udev);
 193                 break;
 194         case EVENT_FINISHED:
 195                 if (msg->devpath_old != NULL) {
 196                         /* "move" event - rename failed file to current name, do not delete failed */
 197                         char filename_failed_old[PATH_SIZE];
 198
 199                         strlcpy(filename_failed_old, udev_get_dev_path(msg->udev), sizeof(filename_failed_old));
 200                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 201                         start = strlcat(filename_failed_old, ".udev/failed/", sizeof(filename_failed_old));
 202                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 203                         util_path_encode(&filename_failed_old[start], sizeof(filename) - start);
 204
 205                         if (rename(filename_failed_old, filename_failed) == 0)
 206                                 info(msg->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 207                                      msg->devpath_old, msg->devpath);
 208                 } else {
 209                         unlink(filename_failed);
 210                         delete_path(msg->udev, filename_failed);
 211                 }
 212
 213                 unlink(filename);
 214                 delete_path(msg->udev, filename);
 215                 break;
 216         case EVENT_FAILED:
 217                 /* move failed event to the failed directory */
 218                 create_path(msg->udev, filename_failed);
 219                 rename(filename, filename_failed);
 220
 221                 /* clean up possibly empty queue directory */
 222                 delete_path(msg->udev, filename);
 223                 break;
 224         }
 225
 226         return;
 227 }
 228
 229 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 230 {
 231         list_del(&msg->node);
 232
 233         /* mark as failed, if "add" event returns non-zero */
 234         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 235                 export_event_state(msg, EVENT_FAILED);
 236         else
 237                 export_event_state(msg, EVENT_FINISHED);
 238
 239         free(msg);
 240 }
 241
 242 static void udev_event_run(struct udevd_uevent_msg *msg)
 243 {
 244         pid_t pid;
 245         int retval;
 246
 247         pid = fork();
 248         switch (pid) {
 249         case 0:
 250                 /* child */
 251                 close(uevent_netlink_sock);
 252                 udev_ctrl_unref(udev_ctrl);
 253                 if (inotify_fd >= 0)
 254                         close(inotify_fd);
 255                 close(signal_pipe[READ_END]);
 256                 close(signal_pipe[WRITE_END]);
 257                 logging_close();
 258                 logging_init("udevd-event");
 259                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 260
 261                 retval = udev_event_process(msg);
 262                 info(msg->udev, "seq %llu finished with %i\n", msg->seqnum, retval);
 263
 264                 logging_close();
 265                 if (retval)
 266                         exit(1);
 267                 exit(0);
 268         case -1:
 269                 err(msg->udev, "fork of child failed: %s\n", strerror(errno));
 270                 msg_queue_delete(msg);
 271                 break;
 272         default:
 273                 /* get SIGCHLD in main loop */
 274                 info(msg->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 275                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 276                 msg->pid = pid;
 277         }
 278 }
 279
 280 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 281 {
 282         char filename[PATH_SIZE];
 283         int fd;
 284
 285         msg->queue_time = time(NULL);
 286
 287         export_event_state(msg, EVENT_QUEUED);
 288         info(msg->udev, "seq %llu queued, '%s' '%s'\n", msg->seqnum, msg->action, msg->subsystem);
 289
 290         strlcpy(filename, udev_get_dev_path(msg->udev), sizeof(filename));
 291         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 292         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 293         if (fd >= 0) {
 294                 char str[32];
 295                 int len;
 296
 297                 len = sprintf(str, "%llu\n", msg->seqnum);
 298                 write(fd, str, len);
 299                 close(fd);
 300         }
 301
 302         /* run one event after the other in debug mode */
 303         if (debug_trace) {
 304                 list_add_tail(&msg->node, &running_list);
 305                 udev_event_run(msg);
 306                 waitpid(msg->pid, NULL, 0);
 307                 msg_queue_delete(msg);
 308                 return;
 309         }
 310
 311         /* run all events with a timeout set immediately */
 312         if (msg->timeout != 0) {
 313                 list_add_tail(&msg->node, &running_list);
 314                 udev_event_run(msg);
 315                 return;
 316         }
 317
 318         list_add_tail(&msg->node, &exec_list);
 319         run_exec_q = 1;
 320 }
 321
 322 static int mem_size_mb(void)
 323 {
 324         FILE* f;
 325         char buf[4096];
 326         long int memsize = -1;
 327
 328         f = fopen("/proc/meminfo", "r");
 329         if (f == NULL)
 330                 return -1;
 331
 332         while (fgets(buf, sizeof(buf), f) != NULL) {
 333                 long int value;
 334
 335                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 336                         memsize = value / 1024;
 337                         break;
 338                 }
 339         }
 340
 341         fclose(f);
 342         return memsize;
 343 }
 344
 345 static int compare_devpath(const char *running, const char *waiting)
 346 {
 347         int i;
 348
 349         for (i = 0; i < PATH_SIZE; i++) {
 350                 /* identical device event found */
 351                 if (running[i] == '\0' && waiting[i] == '\0')
 352                         return 1;
 353
 354                 /* parent device event found */
 355                 if (running[i] == '\0' && waiting[i] == '/')
 356                         return 2;
 357
 358                 /* child device event found */
 359                 if (running[i] == '/' && waiting[i] == '\0')
 360                         return 3;
 361
 362                 /* no matching event */
 363                 if (running[i] != waiting[i])
 364                         break;
 365         }
 366
 367         return 0;
 368 }
 369
 370 /* lookup event for identical, parent, child, or physical device */
 371 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 372 {
 373         struct udevd_uevent_msg *loop_msg;
 374         int childs_count = 0;
 375
 376         /* check exec-queue which may still contain delayed events we depend on */
 377         list_for_each_entry(loop_msg, &exec_list, node) {
 378                 /* skip ourself and all later events */
 379                 if (loop_msg->seqnum >= msg->seqnum)
 380                         break;
 381
 382                 /* check our old name */
 383                 if (msg->devpath_old != NULL)
 384                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 385                                 return 2;
 386
 387                 /* check identical, parent, or child device event */
 388                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 389                         dbg(msg->udev, "%llu, device event still pending %llu (%s)\n",
 390                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 391                         return 3;
 392                 }
 393
 394                 /* check for our major:minor number */
 395                 if (msg->devt && loop_msg->devt == msg->devt &&
 396                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 397                         dbg(msg->udev, "%llu, device event still pending %llu (%d:%d)\n", msg->seqnum,
 398                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 399                         return 4;
 400                 }
 401
 402                 /* check physical device event (special case of parent) */
 403                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 404                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 405                                 dbg(msg->udev, "%llu, physical device event still pending %llu (%s)\n",
 406                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 407                                 return 5;
 408                         }
 409         }
 410
 411         /* check run queue for still running events */
 412         list_for_each_entry(loop_msg, &running_list, node) {
 413                 childs_count++;
 414
 415                 if (childs_count++ >= limit) {
 416                         info(msg->udev, "%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 417                         return 1;
 418                 }
 419
 420                 /* check our old name */
 421                 if (msg->devpath_old != NULL)
 422                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 423                                 return 2;
 424
 425                 /* check identical, parent, or child device event */
 426                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 427                         dbg(msg->udev, "%llu, device event still running %llu (%s)\n",
 428                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 429                         return 3;
 430                 }
 431
 432                 /* check for our major:minor number */
 433                 if (msg->devt && loop_msg->devt == msg->devt &&
 434                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 435                         dbg(msg->udev, "%llu, device event still running %llu (%d:%d)\n", msg->seqnum,
 436                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 437                         return 4;
 438                 }
 439
 440                 /* check physical device event (special case of parent) */
 441                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 442                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 443                                 dbg(msg->udev, "%llu, physical device event still running %llu (%s)\n",
 444                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 445                                 return 5;
 446                         }
 447         }
 448         return 0;
 449 }
 450
 451 /* serializes events for the identical and parent and child devices */
 452 static void msg_queue_manager(struct udev *udev)
 453 {
 454         struct udevd_uevent_msg *loop_msg;
 455         struct udevd_uevent_msg *tmp_msg;
 456
 457         if (list_empty(&exec_list))
 458                 return;
 459
 460         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 461                 /* serialize and wait for parent or child events */
 462                 if (devpath_busy(loop_msg, max_childs) != 0) {
 463                         dbg(udev, "delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
 464                         continue;
 465                 }
 466
 467                 /* move event to run list */
 468                 list_move_tail(&loop_msg->node, &running_list);
 469                 udev_event_run(loop_msg);
 470                 dbg(udev, "moved seq %llu to running list\n", loop_msg->seqnum);
 471         }
 472 }
 473
 474 static struct udevd_uevent_msg *get_msg_from_envbuf(struct udev *udev, const char *buf, int buf_size)
 475 {
 476         int bufpos;
 477         int i;
 478         struct udevd_uevent_msg *msg;
 479         char *physdevdriver_key = NULL;
 480         int maj = 0;
 481         int min = 0;
 482
 483         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 484         if (msg == NULL)
 485                 return NULL;
 486         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 487         msg->udev = udev;
 488
 489         /* copy environment buffer and reconstruct envp */
 490         memcpy(msg->envbuf, buf, buf_size);
 491         bufpos = 0;
 492         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 493                 int keylen;
 494                 char *key;
 495
 496                 key = &msg->envbuf[bufpos];
 497                 keylen = strlen(key);
 498                 msg->envp[i] = key;
 499                 bufpos += keylen + 1;
 500                 dbg(udev, "add '%s' to msg.envp[%i]\n", msg->envp[i], i);
 501
 502                 /* remember some keys for further processing */
 503                 if (strncmp(key, "ACTION=", 7) == 0)
 504                         msg->action = &key[7];
 505                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 506                         msg->devpath = &key[8];
 507                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 508                         msg->subsystem = &key[10];
 509                 else if (strncmp(key, "DRIVER=", 7) == 0)
 510                         msg->driver = &key[7];
 511                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 512                         msg->seqnum = strtoull(&key[7], NULL, 10);
 513                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 514                         msg->devpath_old = &key[12];
 515                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 516                         msg->physdevpath = &key[12];
 517                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 518                         physdevdriver_key = key;
 519                 else if (strncmp(key, "MAJOR=", 6) == 0)
 520                         maj = strtoull(&key[6], NULL, 10);
 521                 else if (strncmp(key, "MINOR=", 6) == 0)
 522                         min = strtoull(&key[6], NULL, 10);
 523                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 524                         msg->timeout = strtoull(&key[8], NULL, 10);
 525         }
 526         msg->devt = makedev(maj, min);
 527         msg->envp[i++] = "UDEVD_EVENT=1";
 528
 529         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 530                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 531                 msg->envp[i++] = &physdevdriver_key[7];
 532                 msg->driver = &physdevdriver_key[14];
 533         }
 534
 535         msg->envp[i] = NULL;
 536
 537         if (msg->devpath == NULL || msg->action == NULL) {
 538                 info(udev, "DEVPATH or ACTION missing, ignore message\n");
 539                 free(msg);
 540                 return NULL;
 541         }
 542         return msg;
 543 }
 544
 545 /* receive the udevd message from userspace */
 546 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 547 {
 548         struct udev *udev = udev_ctrl_get_udev(uctrl);
 549         struct udev_ctrl_msg *ctrl_msg;
 550         const char *str;
 551         int i;
 552
 553         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 554         if (ctrl_msg == NULL)
 555                 return;
 556
 557         i = udev_ctrl_get_set_log_level(ctrl_msg);
 558         if (i >= 0) {
 559                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 560                 udev_set_log_priority(udev, i);
 561                 sprintf(udev_log_env, "UDEV_LOG=%i", i);
 562                 putenv(udev_log_env);
 563         }
 564
 565         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 566                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 567                 stop_exec_q = 1;
 568         }
 569
 570         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 571                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 572                 stop_exec_q = 0;
 573                 msg_queue_manager(udev);
 574         }
 575
 576         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 577                 info(udev, "udevd message (RELOAD_RULES) received\n");
 578                 reload_config = 1;
 579         }
 580
 581         str = udev_ctrl_get_set_env(ctrl_msg);
 582         if (str != NULL) {
 583                 char *key = strdup(str);
 584                 char *val;
 585
 586                 val = strchr(str, '=');
 587                 if (val != NULL) {
 588                         val[0] = '\0';
 589                         val = &val[1];
 590                         if (val[0] == '\0') {
 591                                 info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 592                                 unsetenv(str);
 593                         } else {
 594                                 info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 595                                 setenv(key, val, 1);
 596                         }
 597                 } else {
 598                         err(udev, "wrong key format '%s'\n", key);
 599                 }
 600                 free(key);
 601         }
 602
 603         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 604         if (i >= 0) {
 605                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 606                 max_childs = i;
 607         }
 608
 609         udev_ctrl_msg_unref(ctrl_msg);
 610 }
 611
 612 /* receive the kernel user event message and do some sanity checks */
 613 static struct udevd_uevent_msg *get_netlink_msg(struct udev *udev)
 614 {
 615         struct udevd_uevent_msg *msg;
 616         int bufpos;
 617         ssize_t size;
 618         static char buffer[UEVENT_BUFFER_SIZE+512];
 619         char *pos;
 620
 621         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 622         if (size <  0) {
 623                 if (errno != EINTR)
 624                         err(udev, "unable to receive kernel netlink message: %s\n", strerror(errno));
 625                 return NULL;
 626         }
 627
 628         if ((size_t)size > sizeof(buffer)-1)
 629                 size = sizeof(buffer)-1;
 630         buffer[size] = '\0';
 631         dbg(udev, "uevent_size=%zi\n", size);
 632
 633         /* start of event payload */
 634         bufpos = strlen(buffer)+1;
 635         msg = get_msg_from_envbuf(udev, &buffer[bufpos], size-bufpos);
 636         if (msg == NULL)
 637                 return NULL;
 638
 639         /* validate message */
 640         pos = strchr(buffer, '@');
 641         if (pos == NULL) {
 642                 err(udev, "invalid uevent '%s'\n", buffer);
 643                 free(msg);
 644                 return NULL;
 645         }
 646         pos[0] = '\0';
 647
 648         if (msg->action == NULL) {
 649                 info(udev, "no ACTION in payload found, skip event '%s'\n", buffer);
 650                 free(msg);
 651                 return NULL;
 652         }
 653
 654         if (strcmp(msg->action, buffer) != 0) {
 655                 err(udev, "ACTION in payload does not match uevent, skip event '%s'\n", buffer);
 656                 free(msg);
 657                 return NULL;
 658         }
 659
 660         return msg;
 661 }
 662
 663 static void asmlinkage sig_handler(int signum)
 664 {
 665         switch (signum) {
 666                 case SIGINT:
 667                 case SIGTERM:
 668                         udev_exit = 1;
 669                         break;
 670                 case SIGCHLD:
 671                         /* set flag, then write to pipe if needed */
 672                         sigchilds_waiting = 1;
 673                         break;
 674                 case SIGHUP:
 675                         reload_config = 1;
 676                         break;
 677         }
 678
 679         /* write to pipe, which will wakeup select() in our mainloop */
 680         write(signal_pipe[WRITE_END], "", 1);
 681 }
 682
 683 static void udev_done(int pid, int exitstatus)
 684 {
 685         /* find msg associated with pid and delete it */
 686         struct udevd_uevent_msg *msg;
 687
 688         list_for_each_entry(msg, &running_list, node) {
 689                 if (msg->pid == pid) {
 690                         info(msg->udev, "seq %llu, pid [%d] exit with %i, %ld seconds old\n", msg->seqnum, msg->pid,
 691                              exitstatus, time(NULL) - msg->queue_time);
 692                         msg->exitstatus = exitstatus;
 693                         msg_queue_delete(msg);
 694
 695                         /* there may be events waiting with the same devpath */
 696                         run_exec_q = 1;
 697                         return;
 698                 }
 699         }
 700 }
 701
 702 static void reap_sigchilds(void)
 703 {
 704         pid_t pid;
 705         int status;
 706
 707         while (1) {
 708                 pid = waitpid(-1, &status, WNOHANG);
 709                 if (pid <= 0)
 710                         break;
 711                 if (WIFEXITED(status))
 712                         status = WEXITSTATUS(status);
 713                 else if (WIFSIGNALED(status))
 714                         status = WTERMSIG(status) + 128;
 715                 else
 716                         status = 0;
 717                 udev_done(pid, status);
 718         }
 719 }
 720
 721 static int init_uevent_netlink_sock(struct udev *udev)
 722 {
 723         struct sockaddr_nl snl;
 724         const int buffersize = 16 * 1024 * 1024;
 725         int retval;
 726
 727         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 728         snl.nl_family = AF_NETLINK;
 729         snl.nl_pid = getpid();
 730         snl.nl_groups = 1;
 731
 732         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 733         if (uevent_netlink_sock == -1) {
 734                 err(udev, "error getting socket: %s\n", strerror(errno));
 735                 return -1;
 736         }
 737
 738         /* set receive buffersize */
 739         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 740
 741         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 742         if (retval < 0) {
 743                 err(udev, "bind failed: %s\n", strerror(errno));
 744                 close(uevent_netlink_sock);
 745                 uevent_netlink_sock = -1;
 746                 return -1;
 747         }
 748         return 0;
 749 }
 750
 751 static void export_initial_seqnum(struct udev *udev)
 752 {
 753         char filename[PATH_SIZE];
 754         int fd;
 755         char seqnum[32];
 756         ssize_t len = 0;
 757
 758         strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 759         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 760         fd = open(filename, O_RDONLY);
 761         if (fd >= 0) {
 762                 len = read(fd, seqnum, sizeof(seqnum)-1);
 763                 close(fd);
 764         }
 765         if (len <= 0) {
 766                 strcpy(seqnum, "0\n");
 767                 len = 3;
 768         }
 769         strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 770         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 771         create_path(udev, filename);
 772         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 773         if (fd >= 0) {
 774                 write(fd, seqnum, len);
 775                 close(fd);
 776         }
 777 }
 778
 779 int main(int argc, char *argv[])
 780 {
 781         struct udev *udev;
 782         int retval;
 783         int fd;
 784         struct sigaction act;
 785         fd_set readfds;
 786         const char *value;
 787         int daemonize = 0;
 788         static const struct option options[] = {
 789                 { "daemon", 0, NULL, 'd' },
 790                 { "debug-trace", 0, NULL, 't' },
 791                 { "debug", 0, NULL, 'D' },
 792                 { "help", 0, NULL, 'h' },
 793                 { "version", 0, NULL, 'V' },
 794                 {}
 795         };
 796         int rc = 1;
 797         int maxfd;
 798
 799         udev = udev_new();
 800         if (udev == NULL)
 801                 goto exit;
 802
 803         logging_init("udevd");
 804         udev_set_log_fn(udev, log_fn);
 805         dbg(udev, "version %s\n", VERSION);
 806
 807         while (1) {
 808                 int option;
 809
 810                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 811                 if (option == -1)
 812                         break;
 813
 814                 switch (option) {
 815                 case 'd':
 816                         daemonize = 1;
 817                         break;
 818                 case 't':
 819                         debug_trace = 1;
 820                         break;
 821                 case 'D':
 822                         debug = 1;
 823                         if (udev_get_log_priority(udev) < LOG_INFO)
 824                                 udev_set_log_priority(udev, LOG_INFO);
 825                         break;
 826                 case 'h':
 827                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
 828                         goto exit;
 829                 case 'V':
 830                         printf("%s\n", VERSION);
 831                         goto exit;
 832                 default:
 833                         goto exit;
 834                 }
 835         }
 836
 837         if (getuid() != 0) {
 838                 fprintf(stderr, "root privileges required\n");
 839                 err(udev, "root privileges required\n");
 840                 goto exit;
 841         }
 842
 843         /* make sure std{in,out,err} fd's are in a sane state */
 844         fd = open("/dev/null", O_RDWR);
 845         if (fd < 0) {
 846                 fprintf(stderr, "cannot open /dev/null\n");
 847                 err(udev, "cannot open /dev/null\n");
 848         }
 849         if (fd > STDIN_FILENO)
 850                 dup2(fd, STDIN_FILENO);
 851         if (write(STDOUT_FILENO, 0, 0) < 0)
 852                 dup2(fd, STDOUT_FILENO);
 853         if (write(STDERR_FILENO, 0, 0) < 0)
 854                 dup2(fd, STDERR_FILENO);
 855
 856         /* init control socket, bind() ensures, that only one udevd instance is running */
 857         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 858         if (udev_ctrl == NULL) {
 859                 fprintf(stderr, "error initializing control socket");
 860                 err(udev, "error initializing udevd socket");
 861                 rc = 1;
 862                 goto exit;
 863         }
 864
 865         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 866                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 867                 err(udev, "error binding control socket, seems udevd is already running\n");
 868                 rc = 1;
 869                 goto exit;
 870         }
 871
 872         if (init_uevent_netlink_sock(udev) < 0) {
 873                 fprintf(stderr, "error initializing netlink socket\n");
 874                 err(udev, "error initializing netlink socket\n");
 875                 rc = 3;
 876                 goto exit;
 877         }
 878
 879         retval = pipe(signal_pipe);
 880         if (retval < 0) {
 881                 err(udev, "error getting pipes: %s\n", strerror(errno));
 882                 goto exit;
 883         }
 884
 885         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 886         if (retval < 0) {
 887                 err(udev, "error fcntl on read pipe: %s\n", strerror(errno));
 888                 goto exit;
 889         }
 890         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 891         if (retval < 0) {
 892                 err(udev, "error fcntl on read pipe: %s\n", strerror(errno));
 893                 goto exit;
 894         }
 895
 896         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 897         if (retval < 0) {
 898                 err(udev, "error fcntl on write pipe: %s\n", strerror(errno));
 899                 goto exit;
 900         }
 901         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 902         if (retval < 0) {
 903                 err(udev, "error fcntl on write pipe: %s\n", strerror(errno));
 904                 goto exit;
 905         }
 906
 907         /* parse the rules and keep them in memory */
 908         sysfs_init();
 909         udev_rules_init(udev, &rules, 1);
 910
 911         export_initial_seqnum(udev);
 912
 913         if (daemonize) {
 914                 pid_t pid;
 915
 916                 pid = fork();
 917                 switch (pid) {
 918                 case 0:
 919                         dbg(udev, "daemonized fork running\n");
 920                         break;
 921                 case -1:
 922                         err(udev, "fork of daemon failed: %s\n", strerror(errno));
 923                         rc = 4;
 924                         goto exit;
 925                 default:
 926                         dbg(udev, "child [%u] running, parent exits\n", pid);
 927                         rc = 0;
 928                         goto exit;
 929                 }
 930         }
 931
 932         /* redirect std{out,err} */
 933         if (!debug) {
 934                 dup2(fd, STDOUT_FILENO);
 935                 dup2(fd, STDERR_FILENO);
 936         }
 937         if (fd > STDERR_FILENO)
 938                 close(fd);
 939
 940         /* set scheduling priority for the daemon */
 941         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 942
 943         chdir("/");
 944         umask(022);
 945         setsid();
 946
 947         /* OOM_DISABLE == -17 */
 948         fd = open("/proc/self/oom_adj", O_RDWR);
 949         if (fd < 0)
 950                 err(udev, "error disabling OOM: %s\n", strerror(errno));
 951         else {
 952                 write(fd, "-17", 3);
 953                 close(fd);
 954         }
 955
 956         fd = open("/dev/kmsg", O_WRONLY);
 957         if (fd > 0) {
 958                 const char *str = "<6>udevd version " VERSION " started\n";
 959
 960                 write(fd, str, strlen(str));
 961                 close(fd);
 962         }
 963
 964         /* set signal handlers */
 965         memset(&act, 0x00, sizeof(struct sigaction));
 966         act.sa_handler = (void (*)(int)) sig_handler;
 967         sigemptyset(&act.sa_mask);
 968         act.sa_flags = SA_RESTART;
 969         sigaction(SIGINT, &act, NULL);
 970         sigaction(SIGTERM, &act, NULL);
 971         sigaction(SIGCHLD, &act, NULL);
 972         sigaction(SIGHUP, &act, NULL);
 973
 974         /* watch rules directory */
 975         inotify_fd = inotify_init();
 976         if (inotify_fd >= 0) {
 977                 if (udev_get_rules_path(udev) != NULL) {
 978                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 979                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 980                 } else {
 981                         char filename[PATH_MAX];
 982
 983                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 984                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 985                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 986                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 987
 988                         /* watch dynamic rules directory */
 989                         strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 990                         strlcat(filename, "/.udev/rules.d", sizeof(filename));
 991                         inotify_add_watch(inotify_fd, filename,
 992                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 993                 }
 994         } else if (errno == ENOSYS)
 995                 err(udev, "the kernel does not support inotify, udevd can't monitor rules file changes\n");
 996         else
 997                 err(udev, "inotify_init failed: %s\n", strerror(errno));
 998
 999         /* maximum limit of forked childs */
1000         value = getenv("UDEVD_MAX_CHILDS");
1001         if (value)
1002                 max_childs = strtoul(value, NULL, 10);
1003         else {
1004                 int memsize = mem_size_mb();
1005                 if (memsize > 0)
1006                         max_childs = 128 + (memsize / 4);
1007                 else
1008                         max_childs = UDEVD_MAX_CHILDS;
1009         }
1010         info(udev, "initialize max_childs to %u\n", max_childs);
1011
1012         /* clear environment for forked event processes */
1013         clearenv();
1014
1015         /* export log_priority , as called programs may want to follow that setting */
1016         sprintf(udev_log_env, "UDEV_LOG=%i", udev_get_log_priority(udev));
1017         putenv(udev_log_env);
1018         if (debug_trace)
1019                 putenv("DEBUG=1");
1020
1021         maxfd = udev_ctrl_get_fd(udev_ctrl);
1022         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1023         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1024         maxfd = UDEV_MAX(maxfd, inotify_fd);
1025
1026         while (!udev_exit) {
1027                 struct udevd_uevent_msg *msg;
1028                 int fdcount;
1029
1030                 FD_ZERO(&readfds);
1031                 FD_SET(signal_pipe[READ_END], &readfds);
1032                 FD_SET(udev_ctrl_get_fd(udev_ctrl), &readfds);
1033                 FD_SET(uevent_netlink_sock, &readfds);
1034                 if (inotify_fd >= 0)
1035                         FD_SET(inotify_fd, &readfds);
1036
1037                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1038                 if (fdcount < 0) {
1039                         if (errno != EINTR)
1040                                 err(udev, "error in select: %s\n", strerror(errno));
1041                         continue;
1042                 }
1043
1044                 /* get control message */
1045                 if (FD_ISSET(udev_ctrl_get_fd(udev_ctrl), &readfds))
1046                         handle_ctrl_msg(udev_ctrl);
1047
1048                 /* get netlink message */
1049                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1050                         msg = get_netlink_msg(udev);
1051                         if (msg)
1052                                 msg_queue_insert(msg);
1053                 }
1054
1055                 /* received a signal, clear our notification pipe */
1056                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1057                         char buf[256];
1058
1059                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1060                 }
1061
1062                 /* rules directory inotify watch */
1063                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1064                         int nbytes;
1065
1066                         /* discard all possible events, we can just reload the config */
1067                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1068                                 char *buf;
1069
1070                                 reload_config = 1;
1071                                 buf = malloc(nbytes);
1072                                 if (buf == NULL) {
1073                                         err(udev, "error getting buffer for inotify, disable watching\n");
1074                                         close(inotify_fd);
1075                                         inotify_fd = -1;
1076                                 }
1077                                 read(inotify_fd, buf, nbytes);
1078                                 free(buf);
1079                         }
1080                 }
1081
1082                 /* rules changed, set by inotify or a HUP signal */
1083                 if (reload_config) {
1084                         reload_config = 0;
1085                         udev_rules_cleanup(&rules);
1086                         udev_rules_init(udev, &rules, 1);
1087                 }
1088
1089                 /* forked child has returned */
1090                 if (sigchilds_waiting) {
1091                         sigchilds_waiting = 0;
1092                         reap_sigchilds();
1093                 }
1094
1095                 if (run_exec_q) {
1096                         run_exec_q = 0;
1097                         if (!stop_exec_q)
1098                                 msg_queue_manager(udev);
1099                 }
1100         }
1101         rc = 0;
1102
1103 exit:
1104         udev_rules_cleanup(&rules);
1105         sysfs_cleanup();
1106
1107         if (signal_pipe[READ_END] >= 0)
1108                 close(signal_pipe[READ_END]);
1109         if (signal_pipe[WRITE_END] >= 0)
1110                 close(signal_pipe[WRITE_END]);
1111
1112         udev_ctrl_unref(udev_ctrl);
1113         if (inotify_fd >= 0)
1114                 close(inotify_fd);
1115         if (uevent_netlink_sock >= 0)
1116                 close(uevent_netlink_sock);
1117
1118         logging_close();
1119         return rc;
1120 }