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