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 <stddef.h>
  20 #include <signal.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <ctype.h>
  27 #include <dirent.h>
  28 #include <fcntl.h>
  29 #include <syslog.h>
  30 #include <time.h>
  31 #include <getopt.h>
  32 #include <sys/select.h>
  33 #include <sys/wait.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <sys/un.h>
  37 #include <sys/stat.h>
  38 #include <sys/ioctl.h>
  39 #include <linux/types.h>
  40 #include <linux/netlink.h>
  41 #ifdef HAVE_INOTIFY
  42 #include <sys/inotify.h>
  43 #endif
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47
  48 #define UDEVD_PRIORITY                  -4
  49 #define UDEV_PRIORITY                   -2
  50
  51 /* maximum limit of forked childs */
  52 #define UDEVD_MAX_CHILDS                256
  53
  54 static int debug;
  55
  56 static void log_fn(struct udev *udev, int priority,
  57                    const char *file, int line, const char *fn,
  58                    const char *format, va_list args)
  59 {
  60         if (debug) {
  61                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  62                 vfprintf(stderr, format, args);
  63         } else {
  64                 vsyslog(priority, format, args);
  65         }
  66 }
  67
  68 struct udevd_uevent_msg {
  69         struct udev *udev;
  70         struct list_head node;
  71         pid_t pid;
  72         int exitstatus;
  73         time_t queue_time;
  74         char *action;
  75         char *devpath;
  76         char *subsystem;
  77         char *driver;
  78         dev_t devt;
  79         unsigned long long seqnum;
  80         char *devpath_old;
  81         char *physdevpath;
  82         unsigned int timeout;
  83         char *envp[UEVENT_NUM_ENVP+1];
  84         char envbuf[];
  85 };
  86
  87 static int debug_trace;
  88 static struct udev_rules rules;
  89 static struct udev_ctrl *udev_ctrl;
  90 static int uevent_netlink_sock = -1;
  91 static int inotify_fd = -1;
  92
  93 static int signal_pipe[2] = {-1, -1};
  94 static volatile int sigchilds_waiting;
  95 static volatile int udev_exit;
  96 static volatile int reload_config;
  97 static int run_exec_q;
  98 static int stop_exec_q;
  99 static int max_childs;
 100 static char udev_log_env[32];
 101
 102 static LIST_HEAD(exec_list);
 103 static LIST_HEAD(running_list);
 104
 105 static void asmlinkage udev_event_sig_handler(int signum)
 106 {
 107         if (signum == SIGALRM)
 108                 exit(1);
 109 }
 110
 111 static int udev_event_process(struct udevd_uevent_msg *msg)
 112 {
 113         struct sigaction act;
 114         struct udevice *udevice;
 115         int i;
 116         int retval;
 117
 118         /* set signal handlers */
 119         memset(&act, 0x00, sizeof(act));
 120         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 121         sigemptyset (&act.sa_mask);
 122         act.sa_flags = 0;
 123         sigaction(SIGALRM, &act, NULL);
 124
 125         /* reset to default */
 126         act.sa_handler = SIG_DFL;
 127         sigaction(SIGINT, &act, NULL);
 128         sigaction(SIGTERM, &act, NULL);
 129         sigaction(SIGCHLD, &act, NULL);
 130         sigaction(SIGHUP, &act, NULL);
 131
 132         /* trigger timeout to prevent hanging processes */
 133         alarm(UDEV_EVENT_TIMEOUT);
 134
 135         /* reconstruct event environment from message */
 136         for (i = 0; msg->envp[i]; i++)
 137                 putenv(msg->envp[i]);
 138
 139         udevice = udev_device_init(msg->udev);
 140         if (udevice == NULL)
 141                 return -1;
 142         util_strlcpy(udevice->action, msg->action, sizeof(udevice->action));
 143         sysfs_device_set_values(udevice->udev, udevice->dev, msg->devpath, msg->subsystem, msg->driver);
 144         udevice->devpath_old = msg->devpath_old;
 145         udevice->devt = msg->devt;
 146
 147         retval = udev_device_event(&rules, udevice);
 148
 149         /* rules may change/disable the timeout */
 150         if (udevice->event_timeout >= 0)
 151                 alarm(udevice->event_timeout);
 152
 153         /* run programs collected by RUN-key*/
 154         if (retval == 0 && !udevice->ignore_device && udev_get_run(msg->udev))
 155                 retval = udev_rules_run(udevice);
 156
 157         udev_device_cleanup(udevice);
 158         return retval;
 159 }
 160
 161 enum event_state {
 162         EVENT_QUEUED,
 163         EVENT_FINISHED,
 164         EVENT_FAILED,
 165 };
 166
 167 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 168 {
 169         char filename[UTIL_PATH_SIZE];
 170         char filename_failed[UTIL_PATH_SIZE];
 171         size_t start;
 172
 173         /* location of queue file */
 174         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu", udev_get_dev_path(msg->udev), msg->seqnum);
 175
 176         /* location of failed file */
 177         util_strlcpy(filename_failed, udev_get_dev_path(msg->udev), sizeof(filename_failed));
 178         util_strlcat(filename_failed, "/", sizeof(filename_failed));
 179         start = util_strlcat(filename_failed, ".udev/failed/", sizeof(filename_failed));
 180         util_strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 181         util_path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 182
 183         switch (state) {
 184         case EVENT_QUEUED:
 185                 unlink(filename_failed);
 186                 delete_path(msg->udev, filename_failed);
 187                 create_path(msg->udev, filename);
 188                 udev_selinux_setfscreatecon(msg->udev, filename, S_IFLNK);
 189                 symlink(msg->devpath, filename);
 190                 udev_selinux_resetfscreatecon(msg->udev);
 191                 break;
 192         case EVENT_FINISHED:
 193                 if (msg->devpath_old != NULL) {
 194                         /* "move" event - rename failed file to current name, do not delete failed */
 195                         char filename_failed_old[UTIL_PATH_SIZE];
 196
 197                         util_strlcpy(filename_failed_old, udev_get_dev_path(msg->udev), sizeof(filename_failed_old));
 198                         util_strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 199                         start = util_strlcat(filename_failed_old, ".udev/failed/", sizeof(filename_failed_old));
 200                         util_strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 201                         util_path_encode(&filename_failed_old[start], sizeof(filename) - start);
 202
 203                         if (rename(filename_failed_old, filename_failed) == 0)
 204                                 info(msg->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 205                                      msg->devpath_old, msg->devpath);
 206                 } else {
 207                         unlink(filename_failed);
 208                         delete_path(msg->udev, filename_failed);
 209                 }
 210
 211                 unlink(filename);
 212                 delete_path(msg->udev, filename);
 213                 break;
 214         case EVENT_FAILED:
 215                 /* move failed event to the failed directory */
 216                 create_path(msg->udev, filename_failed);
 217                 rename(filename, filename_failed);
 218
 219                 /* clean up possibly empty queue directory */
 220                 delete_path(msg->udev, filename);
 221                 break;
 222         }
 223
 224         return;
 225 }
 226
 227 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 228 {
 229         list_del(&msg->node);
 230
 231         /* mark as failed, if "add" event returns non-zero */
 232         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 233                 export_event_state(msg, EVENT_FAILED);
 234         else
 235                 export_event_state(msg, EVENT_FINISHED);
 236
 237         free(msg);
 238 }
 239
 240 static void udev_event_run(struct udevd_uevent_msg *msg)
 241 {
 242         pid_t pid;
 243         int retval;
 244
 245         pid = fork();
 246         switch (pid) {
 247         case 0:
 248                 /* child */
 249                 close(uevent_netlink_sock);
 250                 udev_ctrl_unref(udev_ctrl);
 251                 if (inotify_fd >= 0)
 252                         close(inotify_fd);
 253                 close(signal_pipe[READ_END]);
 254                 close(signal_pipe[WRITE_END]);
 255                 logging_close();
 256                 logging_init("udevd-event");
 257                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 258
 259                 retval = udev_event_process(msg);
 260                 info(msg->udev, "seq %llu finished with %i\n", msg->seqnum, retval);
 261
 262                 logging_close();
 263                 if (retval)
 264                         exit(1);
 265                 exit(0);
 266         case -1:
 267                 err(msg->udev, "fork of child failed: %m\n");
 268                 msg_queue_delete(msg);
 269                 break;
 270         default:
 271                 /* get SIGCHLD in main loop */
 272                 info(msg->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 273                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 274                 msg->pid = pid;
 275         }
 276 }
 277
 278 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 279 {
 280         char filename[UTIL_PATH_SIZE];
 281         int fd;
 282
 283         msg->queue_time = time(NULL);
 284
 285         export_event_state(msg, EVENT_QUEUED);
 286         info(msg->udev, "seq %llu queued, '%s' '%s'\n", msg->seqnum, msg->action, msg->subsystem);
 287
 288         util_strlcpy(filename, udev_get_dev_path(msg->udev), sizeof(filename));
 289         util_strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 290         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 291         if (fd >= 0) {
 292                 char str[32];
 293                 int len;
 294
 295                 len = sprintf(str, "%llu\n", msg->seqnum);
 296                 write(fd, str, len);
 297                 close(fd);
 298         }
 299
 300         /* run one event after the other in debug mode */
 301         if (debug_trace) {
 302                 list_add_tail(&msg->node, &running_list);
 303                 udev_event_run(msg);
 304                 waitpid(msg->pid, NULL, 0);
 305                 msg_queue_delete(msg);
 306                 return;
 307         }
 308
 309         /* run all events with a timeout set immediately */
 310         if (msg->timeout != 0) {
 311                 list_add_tail(&msg->node, &running_list);
 312                 udev_event_run(msg);
 313                 return;
 314         }
 315
 316         list_add_tail(&msg->node, &exec_list);
 317         run_exec_q = 1;
 318 }
 319
 320 static int mem_size_mb(void)
 321 {
 322         FILE* f;
 323         char buf[4096];
 324         long int memsize = -1;
 325
 326         f = fopen("/proc/meminfo", "r");
 327         if (f == NULL)
 328                 return -1;
 329
 330         while (fgets(buf, sizeof(buf), f) != NULL) {
 331                 long int value;
 332
 333                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 334                         memsize = value / 1024;
 335                         break;
 336                 }
 337         }
 338
 339         fclose(f);
 340         return memsize;
 341 }
 342
 343 static int compare_devpath(const char *running, const char *waiting)
 344 {
 345         int i;
 346
 347         for (i = 0; i < UTIL_PATH_SIZE; i++) {
 348                 /* identical device event found */
 349                 if (running[i] == '\0' && waiting[i] == '\0')
 350                         return 1;
 351
 352                 /* parent device event found */
 353                 if (running[i] == '\0' && waiting[i] == '/')
 354                         return 2;
 355
 356                 /* child device event found */
 357                 if (running[i] == '/' && waiting[i] == '\0')
 358                         return 3;
 359
 360                 /* no matching event */
 361                 if (running[i] != waiting[i])
 362                         break;
 363         }
 364
 365         return 0;
 366 }
 367
 368 /* lookup event for identical, parent, child, or physical device */
 369 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 370 {
 371         struct udevd_uevent_msg *loop_msg;
 372         int childs_count = 0;
 373
 374         /* check exec-queue which may still contain delayed events we depend on */
 375         list_for_each_entry(loop_msg, &exec_list, node) {
 376                 /* skip ourself and all later events */
 377                 if (loop_msg->seqnum >= msg->seqnum)
 378                         break;
 379
 380                 /* check our old name */
 381                 if (msg->devpath_old != NULL)
 382                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 383                                 return 2;
 384
 385                 /* check identical, parent, or child device event */
 386                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 387                         dbg(msg->udev, "%llu, device event still pending %llu (%s)\n",
 388                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 389                         return 3;
 390                 }
 391
 392                 /* check for our major:minor number */
 393                 if (msg->devt && loop_msg->devt == msg->devt &&
 394                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 395                         dbg(msg->udev, "%llu, device event still pending %llu (%d:%d)\n", msg->seqnum,
 396                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 397                         return 4;
 398                 }
 399
 400                 /* check physical device event (special case of parent) */
 401                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 402                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 403                                 dbg(msg->udev, "%llu, physical device event still pending %llu (%s)\n",
 404                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 405                                 return 5;
 406                         }
 407         }
 408
 409         /* check run queue for still running events */
 410         list_for_each_entry(loop_msg, &running_list, node) {
 411                 childs_count++;
 412
 413                 if (childs_count++ >= limit) {
 414                         info(msg->udev, "%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 415                         return 1;
 416                 }
 417
 418                 /* check our old name */
 419                 if (msg->devpath_old != NULL)
 420                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 421                                 return 2;
 422
 423                 /* check identical, parent, or child device event */
 424                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 425                         dbg(msg->udev, "%llu, device event still running %llu (%s)\n",
 426                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 427                         return 3;
 428                 }
 429
 430                 /* check for our major:minor number */
 431                 if (msg->devt && loop_msg->devt == msg->devt &&
 432                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 433                         dbg(msg->udev, "%llu, device event still running %llu (%d:%d)\n", msg->seqnum,
 434                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 435                         return 4;
 436                 }
 437
 438                 /* check physical device event (special case of parent) */
 439                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 440                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 441                                 dbg(msg->udev, "%llu, physical device event still running %llu (%s)\n",
 442                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 443                                 return 5;
 444                         }
 445         }
 446         return 0;
 447 }
 448
 449 /* serializes events for the identical and parent and child devices */
 450 static void msg_queue_manager(struct udev *udev)
 451 {
 452         struct udevd_uevent_msg *loop_msg;
 453         struct udevd_uevent_msg *tmp_msg;
 454
 455         if (list_empty(&exec_list))
 456                 return;
 457
 458         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 459                 /* serialize and wait for parent or child events */
 460                 if (devpath_busy(loop_msg, max_childs) != 0) {
 461                         dbg(udev, "delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
 462                         continue;
 463                 }
 464
 465                 /* move event to run list */
 466                 list_move_tail(&loop_msg->node, &running_list);
 467                 udev_event_run(loop_msg);
 468                 dbg(udev, "moved seq %llu to running list\n", loop_msg->seqnum);
 469         }
 470 }
 471
 472 static struct udevd_uevent_msg *get_msg_from_envbuf(struct udev *udev, const char *buf, int buf_size)
 473 {
 474         int bufpos;
 475         int i;
 476         struct udevd_uevent_msg *msg;
 477         char *physdevdriver_key = NULL;
 478         int maj = 0;
 479         int min = 0;
 480
 481         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 482         if (msg == NULL)
 483                 return NULL;
 484         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 485         msg->udev = udev;
 486
 487         /* copy environment buffer and reconstruct envp */
 488         memcpy(msg->envbuf, buf, buf_size);
 489         bufpos = 0;
 490         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 491                 int keylen;
 492                 char *key;
 493
 494                 key = &msg->envbuf[bufpos];
 495                 keylen = strlen(key);
 496                 msg->envp[i] = key;
 497                 bufpos += keylen + 1;
 498                 dbg(udev, "add '%s' to msg.envp[%i]\n", msg->envp[i], i);
 499
 500                 /* remember some keys for further processing */
 501                 if (strncmp(key, "ACTION=", 7) == 0)
 502                         msg->action = &key[7];
 503                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 504                         msg->devpath = &key[8];
 505                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 506                         msg->subsystem = &key[10];
 507                 else if (strncmp(key, "DRIVER=", 7) == 0)
 508                         msg->driver = &key[7];
 509                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 510                         msg->seqnum = strtoull(&key[7], NULL, 10);
 511                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 512                         msg->devpath_old = &key[12];
 513                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 514                         msg->physdevpath = &key[12];
 515                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 516                         physdevdriver_key = key;
 517                 else if (strncmp(key, "MAJOR=", 6) == 0)
 518                         maj = strtoull(&key[6], NULL, 10);
 519                 else if (strncmp(key, "MINOR=", 6) == 0)
 520                         min = strtoull(&key[6], NULL, 10);
 521                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 522                         msg->timeout = strtoull(&key[8], NULL, 10);
 523         }
 524         msg->devt = makedev(maj, min);
 525         msg->envp[i++] = "UDEVD_EVENT=1";
 526
 527         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 528                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 529                 msg->envp[i++] = &physdevdriver_key[7];
 530                 msg->driver = &physdevdriver_key[14];
 531         }
 532
 533         msg->envp[i] = NULL;
 534
 535         if (msg->devpath == NULL || msg->action == NULL) {
 536                 info(udev, "DEVPATH or ACTION missing, ignore message\n");
 537                 free(msg);
 538                 return NULL;
 539         }
 540         return msg;
 541 }
 542
 543 /* receive the udevd message from userspace */
 544 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 545 {
 546         struct udev *udev = udev_ctrl_get_udev(uctrl);
 547         struct udev_ctrl_msg *ctrl_msg;
 548         const char *str;
 549         int i;
 550
 551         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 552         if (ctrl_msg == NULL)
 553                 return;
 554
 555         i = udev_ctrl_get_set_log_level(ctrl_msg);
 556         if (i >= 0) {
 557                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 558                 udev_set_log_priority(udev, i);
 559                 sprintf(udev_log_env, "UDEV_LOG=%i", i);
 560                 putenv(udev_log_env);
 561         }
 562
 563         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 564                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 565                 stop_exec_q = 1;
 566         }
 567
 568         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 569                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 570                 stop_exec_q = 0;
 571                 msg_queue_manager(udev);
 572         }
 573
 574         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 575                 info(udev, "udevd message (RELOAD_RULES) received\n");
 576                 reload_config = 1;
 577         }
 578
 579         str = udev_ctrl_get_set_env(ctrl_msg);
 580         if (str != NULL) {
 581                 char *key = strdup(str);
 582                 char *val;
 583
 584                 val = strchr(str, '=');
 585                 if (val != NULL) {
 586                         val[0] = '\0';
 587                         val = &val[1];
 588                         if (val[0] == '\0') {
 589                                 info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 590                                 unsetenv(str);
 591                         } else {
 592                                 info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 593                                 setenv(key, val, 1);
 594                         }
 595                 } else {
 596                         err(udev, "wrong key format '%s'\n", key);
 597                 }
 598                 free(key);
 599         }
 600
 601         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 602         if (i >= 0) {
 603                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 604                 max_childs = i;
 605         }
 606
 607         udev_ctrl_msg_unref(ctrl_msg);
 608 }
 609
 610 /* receive the kernel user event message and do some sanity checks */
 611 static struct udevd_uevent_msg *get_netlink_msg(struct udev *udev)
 612 {
 613         struct udevd_uevent_msg *msg;
 614         int bufpos;
 615         ssize_t size;
 616         static char buffer[UEVENT_BUFFER_SIZE+512];
 617         char *pos;
 618
 619         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 620         if (size <  0) {
 621                 if (errno != EINTR)
 622                         err(udev, "unable to receive kernel netlink message: %m\n");
 623                 return NULL;
 624         }
 625
 626         if ((size_t)size > sizeof(buffer)-1)
 627                 size = sizeof(buffer)-1;
 628         buffer[size] = '\0';
 629         dbg(udev, "uevent_size=%zi\n", size);
 630
 631         /* start of event payload */
 632         bufpos = strlen(buffer)+1;
 633         msg = get_msg_from_envbuf(udev, &buffer[bufpos], size-bufpos);
 634         if (msg == NULL)
 635                 return NULL;
 636
 637         /* validate message */
 638         pos = strchr(buffer, '@');
 639         if (pos == NULL) {
 640                 err(udev, "invalid uevent '%s'\n", buffer);
 641                 free(msg);
 642                 return NULL;
 643         }
 644         pos[0] = '\0';
 645
 646         if (msg->action == NULL) {
 647                 info(udev, "no ACTION in payload found, skip event '%s'\n", buffer);
 648                 free(msg);
 649                 return NULL;
 650         }
 651
 652         if (strcmp(msg->action, buffer) != 0) {
 653                 err(udev, "ACTION in payload does not match uevent, skip event '%s'\n", buffer);
 654                 free(msg);
 655                 return NULL;
 656         }
 657
 658         return msg;
 659 }
 660
 661 static void asmlinkage sig_handler(int signum)
 662 {
 663         switch (signum) {
 664                 case SIGINT:
 665                 case SIGTERM:
 666                         udev_exit = 1;
 667                         break;
 668                 case SIGCHLD:
 669                         /* set flag, then write to pipe if needed */
 670                         sigchilds_waiting = 1;
 671                         break;
 672                 case SIGHUP:
 673                         reload_config = 1;
 674                         break;
 675         }
 676
 677         /* write to pipe, which will wakeup select() in our mainloop */
 678         write(signal_pipe[WRITE_END], "", 1);
 679 }
 680
 681 static void udev_done(int pid, int exitstatus)
 682 {
 683         /* find msg associated with pid and delete it */
 684         struct udevd_uevent_msg *msg;
 685
 686         list_for_each_entry(msg, &running_list, node) {
 687                 if (msg->pid == pid) {
 688                         info(msg->udev, "seq %llu, pid [%d] exit with %i, %ld seconds old\n", msg->seqnum, msg->pid,
 689                              exitstatus, time(NULL) - msg->queue_time);
 690                         msg->exitstatus = exitstatus;
 691                         msg_queue_delete(msg);
 692
 693                         /* there may be events waiting with the same devpath */
 694                         run_exec_q = 1;
 695                         return;
 696                 }
 697         }
 698 }
 699
 700 static void reap_sigchilds(void)
 701 {
 702         pid_t pid;
 703         int status;
 704
 705         while (1) {
 706                 pid = waitpid(-1, &status, WNOHANG);
 707                 if (pid <= 0)
 708                         break;
 709                 if (WIFEXITED(status))
 710                         status = WEXITSTATUS(status);
 711                 else if (WIFSIGNALED(status))
 712                         status = WTERMSIG(status) + 128;
 713                 else
 714                         status = 0;
 715                 udev_done(pid, status);
 716         }
 717 }
 718
 719 static int init_uevent_netlink_sock(struct udev *udev)
 720 {
 721         struct sockaddr_nl snl;
 722         const int buffersize = 16 * 1024 * 1024;
 723         int retval;
 724
 725         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 726         snl.nl_family = AF_NETLINK;
 727         snl.nl_pid = getpid();
 728         snl.nl_groups = 1;
 729
 730         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 731         if (uevent_netlink_sock == -1) {
 732                 err(udev, "error getting socket: %m\n");
 733                 return -1;
 734         }
 735
 736         /* set receive buffersize */
 737         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 738
 739         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 740         if (retval < 0) {
 741                 err(udev, "bind failed: %m\n");
 742                 close(uevent_netlink_sock);
 743                 uevent_netlink_sock = -1;
 744                 return -1;
 745         }
 746         return 0;
 747 }
 748
 749 static void export_initial_seqnum(struct udev *udev)
 750 {
 751         char filename[UTIL_PATH_SIZE];
 752         int fd;
 753         char seqnum[32];
 754         ssize_t len = 0;
 755
 756         util_strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 757         util_strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 758         fd = open(filename, O_RDONLY);
 759         if (fd >= 0) {
 760                 len = read(fd, seqnum, sizeof(seqnum)-1);
 761                 close(fd);
 762         }
 763         if (len <= 0) {
 764                 strcpy(seqnum, "0\n");
 765                 len = 3;
 766         }
 767         util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 768         util_strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 769         create_path(udev, filename);
 770         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 771         if (fd >= 0) {
 772                 write(fd, seqnum, len);
 773                 close(fd);
 774         }
 775 }
 776
 777 int main(int argc, char *argv[])
 778 {
 779         struct udev *udev;
 780         int retval;
 781         int fd;
 782         struct sigaction act;
 783         fd_set readfds;
 784         const char *value;
 785         int daemonize = 0;
 786         static const struct option options[] = {
 787                 { "daemon", no_argument, NULL, 'd' },
 788                 { "debug-trace", no_argument, NULL, 't' },
 789                 { "debug", no_argument, NULL, 'D' },
 790                 { "help", no_argument, NULL, 'h' },
 791                 { "version", no_argument, NULL, 'V' },
 792                 {}
 793         };
 794         int rc = 1;
 795         int maxfd;
 796
 797         udev = udev_new();
 798         if (udev == NULL)
 799                 goto exit;
 800
 801         logging_init("udevd");
 802         udev_set_log_fn(udev, log_fn);
 803         dbg(udev, "version %s\n", VERSION);
 804
 805         while (1) {
 806                 int option;
 807
 808                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 809                 if (option == -1)
 810                         break;
 811
 812                 switch (option) {
 813                 case 'd':
 814                         daemonize = 1;
 815                         break;
 816                 case 't':
 817                         debug_trace = 1;
 818                         break;
 819                 case 'D':
 820                         debug = 1;
 821                         if (udev_get_log_priority(udev) < LOG_INFO)
 822                                 udev_set_log_priority(udev, LOG_INFO);
 823                         break;
 824                 case 'h':
 825                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
 826                         goto exit;
 827                 case 'V':
 828                         printf("%s\n", VERSION);
 829                         goto exit;
 830                 default:
 831                         goto exit;
 832                 }
 833         }
 834
 835         if (getuid() != 0) {
 836                 fprintf(stderr, "root privileges required\n");
 837                 err(udev, "root privileges required\n");
 838                 goto exit;
 839         }
 840
 841         /* make sure std{in,out,err} fd's are in a sane state */
 842         fd = open("/dev/null", O_RDWR);
 843         if (fd < 0) {
 844                 fprintf(stderr, "cannot open /dev/null\n");
 845                 err(udev, "cannot open /dev/null\n");
 846         }
 847         if (fd > STDIN_FILENO)
 848                 dup2(fd, STDIN_FILENO);
 849         if (write(STDOUT_FILENO, 0, 0) < 0)
 850                 dup2(fd, STDOUT_FILENO);
 851         if (write(STDERR_FILENO, 0, 0) < 0)
 852                 dup2(fd, STDERR_FILENO);
 853
 854         /* init control socket, bind() ensures, that only one udevd instance is running */
 855         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 856         if (udev_ctrl == NULL) {
 857                 fprintf(stderr, "error initializing control socket");
 858                 err(udev, "error initializing udevd socket");
 859                 rc = 1;
 860                 goto exit;
 861         }
 862
 863         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 864                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 865                 err(udev, "error binding control socket, seems udevd is already running\n");
 866                 rc = 1;
 867                 goto exit;
 868         }
 869
 870         if (init_uevent_netlink_sock(udev) < 0) {
 871                 fprintf(stderr, "error initializing netlink socket\n");
 872                 err(udev, "error initializing netlink socket\n");
 873                 rc = 3;
 874                 goto exit;
 875         }
 876
 877         retval = pipe(signal_pipe);
 878         if (retval < 0) {
 879                 err(udev, "error getting pipes: %m\n");
 880                 goto exit;
 881         }
 882
 883         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 884         if (retval < 0) {
 885                 err(udev, "error fcntl on read pipe: %m\n");
 886                 goto exit;
 887         }
 888         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 889         if (retval < 0) {
 890                 err(udev, "error fcntl on read pipe: %m\n");
 891                 goto exit;
 892         }
 893
 894         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 895         if (retval < 0) {
 896                 err(udev, "error fcntl on write pipe: %m\n");
 897                 goto exit;
 898         }
 899         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 900         if (retval < 0) {
 901                 err(udev, "error fcntl on write pipe: %m\n");
 902                 goto exit;
 903         }
 904
 905         /* parse the rules and keep them in memory */
 906         sysfs_init();
 907         udev_rules_init(udev, &rules, 1);
 908
 909         export_initial_seqnum(udev);
 910
 911         if (daemonize) {
 912                 pid_t pid;
 913
 914                 pid = fork();
 915                 switch (pid) {
 916                 case 0:
 917                         dbg(udev, "daemonized fork running\n");
 918                         break;
 919                 case -1:
 920                         err(udev, "fork of daemon failed: %m\n");
 921                         rc = 4;
 922                         goto exit;
 923                 default:
 924                         dbg(udev, "child [%u] running, parent exits\n", pid);
 925                         rc = 0;
 926                         goto exit;
 927                 }
 928         }
 929
 930         /* redirect std{out,err} */
 931         if (!debug) {
 932                 dup2(fd, STDOUT_FILENO);
 933                 dup2(fd, STDERR_FILENO);
 934         }
 935         if (fd > STDERR_FILENO)
 936                 close(fd);
 937
 938         /* set scheduling priority for the daemon */
 939         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 940
 941         chdir("/");
 942         umask(022);
 943         setsid();
 944
 945         /* OOM_DISABLE == -17 */
 946         fd = open("/proc/self/oom_adj", O_RDWR);
 947         if (fd < 0)
 948                 err(udev, "error disabling OOM: %m\n");
 949         else {
 950                 write(fd, "-17", 3);
 951                 close(fd);
 952         }
 953
 954         fd = open("/dev/kmsg", O_WRONLY);
 955         if (fd > 0) {
 956                 const char *ver_str = "<6>udev: starting version " VERSION "\n";
 957                 char path[UTIL_PATH_SIZE];
 958                 struct stat statbuf;
 959
 960                 write(fd, ver_str, strlen(ver_str));
 961                 util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 962                 util_strlcat(path, "/class/mem/null", sizeof(path));
 963                 if (lstat(path, &statbuf) == 0) {
 964                         if (S_ISDIR(statbuf.st_mode)) {
 965                                 const char *depr_str = "<6>udev: deprecated sysfs layout "
 966                                                        "(CONFIG_SYSFS_DEPRECATED) is unsupported\n";
 967
 968                                 write(fd, depr_str, strlen(depr_str));
 969                         }
 970                 }
 971                 close(fd);
 972         }
 973
 974         /* set signal handlers */
 975         memset(&act, 0x00, sizeof(struct sigaction));
 976         act.sa_handler = (void (*)(int)) sig_handler;
 977         sigemptyset(&act.sa_mask);
 978         act.sa_flags = SA_RESTART;
 979         sigaction(SIGINT, &act, NULL);
 980         sigaction(SIGTERM, &act, NULL);
 981         sigaction(SIGCHLD, &act, NULL);
 982         sigaction(SIGHUP, &act, NULL);
 983
 984         /* watch rules directory */
 985         inotify_fd = inotify_init();
 986         if (inotify_fd >= 0) {
 987                 if (udev_get_rules_path(udev) != NULL) {
 988                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 989                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 990                 } else {
 991                         char filename[PATH_MAX];
 992
 993                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 994                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 995                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 996                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 997
 998                         /* watch dynamic rules directory */
 999                         util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
1000                         util_strlcat(filename, "/.udev/rules.d", sizeof(filename));
1001                         inotify_add_watch(inotify_fd, filename,
1002                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1003                 }
1004         } else if (errno == ENOSYS)
1005                 err(udev, "the kernel does not support inotify, udevd can't monitor rules file changes\n");
1006         else
1007                 err(udev, "inotify_init failed: %m\n");
1008
1009         /* maximum limit of forked childs */
1010         value = getenv("UDEVD_MAX_CHILDS");
1011         if (value)
1012                 max_childs = strtoul(value, NULL, 10);
1013         else {
1014                 int memsize = mem_size_mb();
1015                 if (memsize > 0)
1016                         max_childs = 128 + (memsize / 4);
1017                 else
1018                         max_childs = UDEVD_MAX_CHILDS;
1019         }
1020         info(udev, "initialize max_childs to %u\n", max_childs);
1021
1022         /* clear environment for forked event processes */
1023         clearenv();
1024
1025         /* export log_priority , as called programs may want to follow that setting */
1026         sprintf(udev_log_env, "UDEV_LOG=%i", udev_get_log_priority(udev));
1027         putenv(udev_log_env);
1028         if (debug_trace)
1029                 putenv("DEBUG=1");
1030
1031         maxfd = udev_ctrl_get_fd(udev_ctrl);
1032         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1033         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1034         maxfd = UDEV_MAX(maxfd, inotify_fd);
1035
1036         while (!udev_exit) {
1037                 struct udevd_uevent_msg *msg;
1038                 int fdcount;
1039
1040                 FD_ZERO(&readfds);
1041                 FD_SET(signal_pipe[READ_END], &readfds);
1042                 FD_SET(udev_ctrl_get_fd(udev_ctrl), &readfds);
1043                 FD_SET(uevent_netlink_sock, &readfds);
1044                 if (inotify_fd >= 0)
1045                         FD_SET(inotify_fd, &readfds);
1046
1047                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1048                 if (fdcount < 0) {
1049                         if (errno != EINTR)
1050                                 err(udev, "error in select: %m\n");
1051                         continue;
1052                 }
1053
1054                 /* get control message */
1055                 if (FD_ISSET(udev_ctrl_get_fd(udev_ctrl), &readfds))
1056                         handle_ctrl_msg(udev_ctrl);
1057
1058                 /* get netlink message */
1059                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1060                         msg = get_netlink_msg(udev);
1061                         if (msg)
1062                                 msg_queue_insert(msg);
1063                 }
1064
1065                 /* received a signal, clear our notification pipe */
1066                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1067                         char buf[256];
1068
1069                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1070                 }
1071
1072                 /* rules directory inotify watch */
1073                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1074                         int nbytes;
1075
1076                         /* discard all possible events, we can just reload the config */
1077                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1078                                 char *buf;
1079
1080                                 reload_config = 1;
1081                                 buf = malloc(nbytes);
1082                                 if (buf == NULL) {
1083                                         err(udev, "error getting buffer for inotify, disable watching\n");
1084                                         close(inotify_fd);
1085                                         inotify_fd = -1;
1086                                 }
1087                                 read(inotify_fd, buf, nbytes);
1088                                 free(buf);
1089                         }
1090                 }
1091
1092                 /* rules changed, set by inotify or a HUP signal */
1093                 if (reload_config) {
1094                         reload_config = 0;
1095                         udev_rules_cleanup(&rules);
1096                         udev_rules_init(udev, &rules, 1);
1097                 }
1098
1099                 /* forked child has returned */
1100                 if (sigchilds_waiting) {
1101                         sigchilds_waiting = 0;
1102                         reap_sigchilds();
1103                 }
1104
1105                 if (run_exec_q) {
1106                         run_exec_q = 0;
1107                         if (!stop_exec_q)
1108                                 msg_queue_manager(udev);
1109                 }
1110         }
1111         rc = 0;
1112
1113 exit:
1114         udev_rules_cleanup(&rules);
1115         sysfs_cleanup();
1116
1117         if (signal_pipe[READ_END] >= 0)
1118                 close(signal_pipe[READ_END]);
1119         if (signal_pipe[WRITE_END] >= 0)
1120                 close(signal_pipe[WRITE_END]);
1121
1122         udev_ctrl_unref(udev_ctrl);
1123         if (inotify_fd >= 0)
1124                 close(inotify_fd);
1125         if (uevent_netlink_sock >= 0)
1126                 close(uevent_netlink_sock);
1127
1128         logging_close();
1129         return rc;
1130 }