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 <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static int debug_trace;
  49 static int debug;
  50
  51 static struct udev_rules rules;
  52 static int udevd_sock = -1;
  53 static int uevent_netlink_sock = -1;
  54 static int inotify_fd = -1;
  55 static pid_t sid;
  56
  57 static int signal_pipe[2] = {-1, -1};
  58 static volatile int sigchilds_waiting;
  59 static volatile int udev_exit;
  60 static volatile int reload_config;
  61 static int run_exec_q;
  62 static int stop_exec_q;
  63 static int max_childs;
  64 static int max_childs_running;
  65 static char udev_log[32];
  66
  67 static LIST_HEAD(exec_list);
  68 static LIST_HEAD(running_list);
  69
  70
  71 #ifdef USE_LOG
  72 void log_message(int priority, const char *format, ...)
  73 {
  74         va_list args;
  75
  76         if (priority > udev_log_priority)
  77                 return;
  78
  79         va_start(args, format);
  80         if (debug) {
  81                 printf("[%d] ", (int) getpid());
  82                 vprintf(format, args);
  83         } else
  84                 vsyslog(priority, format, args);
  85         va_end(args);
  86 }
  87
  88 #endif
  89
  90 static void asmlinkage udev_event_sig_handler(int signum)
  91 {
  92         if (signum == SIGALRM)
  93                 exit(1);
  94 }
  95
  96 static int udev_event_process(struct udevd_uevent_msg *msg)
  97 {
  98         struct sigaction act;
  99         struct udevice *udev;
 100         int i;
 101         int retval;
 102
 103         /* set signal handlers */
 104         memset(&act, 0x00, sizeof(act));
 105         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 106         sigemptyset (&act.sa_mask);
 107         act.sa_flags = 0;
 108         sigaction(SIGALRM, &act, NULL);
 109
 110         /* reset to default */
 111         act.sa_handler = SIG_DFL;
 112         sigaction(SIGINT, &act, NULL);
 113         sigaction(SIGTERM, &act, NULL);
 114         sigaction(SIGCHLD, &act, NULL);
 115         sigaction(SIGHUP, &act, NULL);
 116
 117         /* trigger timeout to prevent hanging processes */
 118         alarm(UDEV_EVENT_TIMEOUT);
 119
 120         /* reconstruct event environment from message */
 121         for (i = 0; msg->envp[i]; i++)
 122                 putenv(msg->envp[i]);
 123
 124         udev = udev_device_init(NULL);
 125         if (udev == NULL)
 126                 return -1;
 127         strlcpy(udev->action, msg->action, sizeof(udev->action));
 128         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 129         udev->devpath_old = msg->devpath_old;
 130         udev->devt = msg->devt;
 131
 132         retval = udev_device_event(&rules, udev);
 133
 134         /* rules may change/disable the timeout */
 135         if (udev->event_timeout >= 0)
 136                 alarm(udev->event_timeout);
 137
 138         /* run programs collected by RUN-key*/
 139         if (retval == 0 && !udev->ignore_device && udev_run)
 140                 retval = udev_rules_run(udev);
 141
 142         udev_device_cleanup(udev);
 143         return retval;
 144 }
 145
 146 enum event_state {
 147         EVENT_QUEUED,
 148         EVENT_FINISHED,
 149         EVENT_FAILED,
 150 };
 151
 152 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 153 {
 154         char filename[PATH_SIZE];
 155         char filename_failed[PATH_SIZE];
 156         size_t start;
 157
 158         /* location of queue file */
 159         snprintf(filename, sizeof(filename), "%s/"EVENT_QUEUE_DIR"/%llu", udev_root, msg->seqnum);
 160
 161         /* location of failed file */
 162         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 163         strlcat(filename_failed, "/", sizeof(filename_failed));
 164         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 165         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 166         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 167
 168         switch (state) {
 169         case EVENT_QUEUED:
 170                 unlink(filename_failed);
 171                 delete_path(filename_failed);
 172
 173                 create_path(filename);
 174                 selinux_setfscreatecon(filename, NULL, S_IFLNK);
 175                 symlink(msg->devpath, filename);
 176                 selinux_resetfscreatecon();
 177                 break;
 178         case EVENT_FINISHED:
 179                 if (msg->devpath_old != NULL) {
 180                         /* "move" event - rename failed file to current name, do not delete failed */
 181                         char filename_failed_old[PATH_SIZE];
 182
 183                         strlcpy(filename_failed_old, udev_root, sizeof(filename_failed_old));
 184                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 185                         start = strlcat(filename_failed_old, EVENT_FAILED_DIR"/", sizeof(filename_failed_old));
 186                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 187                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 188
 189                         if (rename(filename_failed_old, filename_failed) == 0)
 190                                 info("renamed devpath, moved failed state of '%s' to %s'\n",
 191                                      msg->devpath_old, msg->devpath);
 192                 } else {
 193                         unlink(filename_failed);
 194                         delete_path(filename_failed);
 195                 }
 196
 197                 unlink(filename);
 198                 delete_path(filename);
 199                 break;
 200         case EVENT_FAILED:
 201                 /* move failed event to the failed directory */
 202                 create_path(filename_failed);
 203                 rename(filename, filename_failed);
 204
 205                 /* clean up possibly empty queue directory */
 206                 delete_path(filename);
 207                 break;
 208         }
 209
 210         return;
 211 }
 212
 213 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 214 {
 215         list_del(&msg->node);
 216
 217         /* mark as failed, if "add" event returns non-zero */
 218         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 219                 export_event_state(msg, EVENT_FAILED);
 220         else
 221                 export_event_state(msg, EVENT_FINISHED);
 222
 223         free(msg);
 224 }
 225
 226 static void udev_event_run(struct udevd_uevent_msg *msg)
 227 {
 228         pid_t pid;
 229         int retval;
 230
 231         pid = fork();
 232         switch (pid) {
 233         case 0:
 234                 /* child */
 235                 close(uevent_netlink_sock);
 236                 close(udevd_sock);
 237                 if (inotify_fd >= 0)
 238                         close(inotify_fd);
 239                 close(signal_pipe[READ_END]);
 240                 close(signal_pipe[WRITE_END]);
 241                 logging_close();
 242
 243                 logging_init("udevd-event");
 244                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 245
 246                 retval = udev_event_process(msg);
 247                 info("seq %llu finished with %i\n", msg->seqnum, retval);
 248
 249                 logging_close();
 250                 if (retval)
 251                         exit(1);
 252                 exit(0);
 253         case -1:
 254                 err("fork of child failed: %s\n", strerror(errno));
 255                 msg_queue_delete(msg);
 256                 break;
 257         default:
 258                 /* get SIGCHLD in main loop */
 259                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 260                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 261                 msg->pid = pid;
 262         }
 263 }
 264
 265 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 266 {
 267         char filename[PATH_SIZE];
 268         int fd;
 269
 270         msg->queue_time = time(NULL);
 271
 272         strlcpy(filename, udev_root, sizeof(filename));
 273         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 274         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 275         if (fd >= 0) {
 276                 char str[32];
 277                 int len;
 278
 279                 len = sprintf(str, "%llu\n", msg->seqnum);
 280                 write(fd, str, len);
 281                 close(fd);
 282         }
 283
 284         export_event_state(msg, EVENT_QUEUED);
 285         info("seq %llu queued, '%s' '%s'\n", msg->seqnum, msg->action, msg->subsystem);
 286
 287         /* run one event after the other in debug mode */
 288         if (debug_trace) {
 289                 list_add_tail(&msg->node, &running_list);
 290                 udev_event_run(msg);
 291                 waitpid(msg->pid, NULL, 0);
 292                 msg_queue_delete(msg);
 293                 return;
 294         }
 295
 296         /* run all events with a timeout set immediately */
 297         if (msg->timeout != 0) {
 298                 list_add_tail(&msg->node, &running_list);
 299                 udev_event_run(msg);
 300                 return;
 301         }
 302
 303         list_add_tail(&msg->node, &exec_list);
 304         run_exec_q = 1;
 305 }
 306
 307 static int mem_size_mb(void)
 308 {
 309         FILE* f;
 310         char buf[4096];
 311         long int memsize = -1;
 312
 313         f = fopen("/proc/meminfo", "r");
 314         if (f == NULL)
 315                 return -1;
 316
 317         while (fgets(buf, sizeof(buf), f) != NULL) {
 318                 long int value;
 319
 320                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 321                         memsize = value / 1024;
 322                         break;
 323                 }
 324         }
 325
 326         fclose(f);
 327         return memsize;
 328 }
 329
 330 static int cpu_count(void)
 331 {
 332         FILE* f;
 333         char buf[4096];
 334         int count = 0;
 335
 336         f = fopen("/proc/stat", "r");
 337         if (f == NULL)
 338                 return -1;
 339
 340         while (fgets(buf, sizeof(buf), f) != NULL) {
 341                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 342                         count++;
 343         }
 344
 345         fclose(f);
 346         if (count == 0)
 347                 return -1;
 348         return count;
 349 }
 350
 351 static int running_processes(void)
 352 {
 353         FILE* f;
 354         char buf[4096];
 355         int running = -1;
 356
 357         f = fopen("/proc/stat", "r");
 358         if (f == NULL)
 359                 return -1;
 360
 361         while (fgets(buf, sizeof(buf), f) != NULL) {
 362                 int value;
 363
 364                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 365                         running = value;
 366                         break;
 367                 }
 368         }
 369
 370         fclose(f);
 371         return running;
 372 }
 373
 374 /* return the number of process es in our session, count only until limit */
 375 static int running_processes_in_session(pid_t session, int limit)
 376 {
 377         DIR *dir;
 378         struct dirent *dent;
 379         int running = 0;
 380
 381         dir = opendir("/proc");
 382         if (!dir)
 383                 return -1;
 384
 385         /* read process info from /proc */
 386         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 387                 int f;
 388                 char procdir[64];
 389                 char line[256];
 390                 const char *pos;
 391                 char state;
 392                 pid_t ppid, pgrp, sess;
 393                 int len;
 394
 395                 if (!isdigit(dent->d_name[0]))
 396                         continue;
 397
 398                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 399                 procdir[sizeof(procdir)-1] = '\0';
 400
 401                 f = open(procdir, O_RDONLY);
 402                 if (f == -1)
 403                         continue;
 404
 405                 len = read(f, line, sizeof(line)-1);
 406                 close(f);
 407
 408                 if (len <= 0)
 409                         continue;
 410                 else
 411                         line[len] = '\0';
 412
 413                 /* skip ugly program name */
 414                 pos = strrchr(line, ')') + 2;
 415                 if (pos == NULL)
 416                         continue;
 417
 418                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 419                         continue;
 420
 421                 /* count only processes in our session */
 422                 if (sess != session)
 423                         continue;
 424
 425                 /* count only running, no sleeping processes */
 426                 if (state != 'R')
 427                         continue;
 428
 429                 running++;
 430                 if (limit > 0 && running >= limit)
 431                         break;
 432         }
 433         closedir(dir);
 434
 435         return running;
 436 }
 437
 438 static int compare_devpath(const char *running, const char *waiting)
 439 {
 440         int i;
 441
 442         for (i = 0; i < PATH_SIZE; i++) {
 443                 /* identical device event found */
 444                 if (running[i] == '\0' && waiting[i] == '\0')
 445                         return 1;
 446
 447                 /* parent device event found */
 448                 if (running[i] == '\0' && waiting[i] == '/')
 449                         return 2;
 450
 451                 /* child device event found */
 452                 if (running[i] == '/' && waiting[i] == '\0')
 453                         return 3;
 454
 455                 /* no matching event */
 456                 if (running[i] != waiting[i])
 457                         break;
 458         }
 459
 460         return 0;
 461 }
 462
 463 /* lookup event for identical, parent, child, or physical device */
 464 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 465 {
 466         struct udevd_uevent_msg *loop_msg;
 467         int childs_count = 0;
 468
 469         /* check exec-queue which may still contain delayed events we depend on */
 470         list_for_each_entry(loop_msg, &exec_list, node) {
 471                 /* skip ourself and all later events */
 472                 if (loop_msg->seqnum >= msg->seqnum)
 473                         break;
 474
 475                 /* check our old name */
 476                 if (msg->devpath_old != NULL)
 477                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 478                                 return 2;
 479
 480                 /* check identical, parent, or child device event */
 481                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 482                         dbg("%llu, device event still pending %llu (%s)\n",
 483                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 484                         return 3;
 485                 }
 486
 487                 /* check for our major:minor number */
 488                 if (msg->devt && loop_msg->devt == msg->devt &&
 489                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 490                         dbg("%llu, device event still pending %llu (%d:%d)\n", msg->seqnum,
 491                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 492                         return 4;
 493                 }
 494
 495                 /* check physical device event (special case of parent) */
 496                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 497                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 498                                 dbg("%llu, physical device event still pending %llu (%s)\n",
 499                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 500                                 return 5;
 501                         }
 502         }
 503
 504         /* check run queue for still running events */
 505         list_for_each_entry(loop_msg, &running_list, node) {
 506                 if (limit && childs_count++ > limit) {
 507                         dbg("%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 508                         return 1;
 509                 }
 510
 511                 /* check our old name */
 512                 if (msg->devpath_old != NULL)
 513                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 514                                 return 2;
 515
 516                 /* check identical, parent, or child device event */
 517                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 518                         dbg("%llu, device event still running %llu (%s)\n",
 519                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 520                         return 3;
 521                 }
 522
 523                 /* check for our major:minor number */
 524                 if (msg->devt && loop_msg->devt == msg->devt &&
 525                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 526                         dbg("%llu, device event still running %llu (%d:%d)\n", msg->seqnum,
 527                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 528                         return 4;
 529                 }
 530
 531                 /* check physical device event (special case of parent) */
 532                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 533                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 534                                 dbg("%llu, physical device event still running %llu (%s)\n",
 535                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 536                                 return 5;
 537                         }
 538         }
 539         return 0;
 540 }
 541
 542 /* serializes events for the identical and parent and child devices */
 543 static void msg_queue_manager(void)
 544 {
 545         struct udevd_uevent_msg *loop_msg;
 546         struct udevd_uevent_msg *tmp_msg;
 547         int running;
 548
 549         if (list_empty(&exec_list))
 550                 return;
 551
 552         running = running_processes();
 553         dbg("%d processes runnning on system\n", running);
 554         if (running < 0)
 555                 running = max_childs_running;
 556
 557         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 558                 /* check running processes in our session and possibly throttle */
 559                 if (running >= max_childs_running) {
 560                         running = running_processes_in_session(sid, max_childs_running+10);
 561                         dbg("at least %d processes running in session\n", running);
 562                         if (running >= max_childs_running) {
 563                                 dbg("delay seq %llu, too many processes already running\n", loop_msg->seqnum);
 564                                 return;
 565                         }
 566                 }
 567
 568                 /* serialize and wait for parent or child events */
 569                 if (devpath_busy(loop_msg, max_childs) != 0) {
 570                         dbg("delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
 571                         continue;
 572                 }
 573
 574                 /* move event to run list */
 575                 list_move_tail(&loop_msg->node, &running_list);
 576                 udev_event_run(loop_msg);
 577                 running++;
 578                 dbg("moved seq %llu to running list\n", loop_msg->seqnum);
 579         }
 580 }
 581
 582 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 583 {
 584         int bufpos;
 585         int i;
 586         struct udevd_uevent_msg *msg;
 587         char *physdevdriver_key = NULL;
 588         int maj = 0;
 589         int min = 0;
 590
 591         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 592         if (msg == NULL)
 593                 return NULL;
 594         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 595
 596         /* copy environment buffer and reconstruct envp */
 597         memcpy(msg->envbuf, buf, buf_size);
 598         bufpos = 0;
 599         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 600                 int keylen;
 601                 char *key;
 602
 603                 key = &msg->envbuf[bufpos];
 604                 keylen = strlen(key);
 605                 msg->envp[i] = key;
 606                 bufpos += keylen + 1;
 607                 dbg("add '%s' to msg.envp[%i]\n", msg->envp[i], i);
 608
 609                 /* remember some keys for further processing */
 610                 if (strncmp(key, "ACTION=", 7) == 0)
 611                         msg->action = &key[7];
 612                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 613                         msg->devpath = &key[8];
 614                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 615                         msg->subsystem = &key[10];
 616                 else if (strncmp(key, "DRIVER=", 7) == 0)
 617                         msg->driver = &key[7];
 618                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 619                         msg->seqnum = strtoull(&key[7], NULL, 10);
 620                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 621                         msg->devpath_old = &key[12];
 622                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 623                         msg->physdevpath = &key[12];
 624                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 625                         physdevdriver_key = key;
 626                 else if (strncmp(key, "MAJOR=", 6) == 0)
 627                         maj = strtoull(&key[6], NULL, 10);
 628                 else if (strncmp(key, "MINOR=", 6) == 0)
 629                         min = strtoull(&key[6], NULL, 10);
 630                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 631                         msg->timeout = strtoull(&key[8], NULL, 10);
 632         }
 633         msg->devt = makedev(maj, min);
 634         msg->envp[i++] = "UDEVD_EVENT=1";
 635
 636         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 637                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 638                 msg->envp[i++] = &physdevdriver_key[7];
 639                 msg->driver = &physdevdriver_key[14];
 640         }
 641
 642         msg->envp[i] = NULL;
 643
 644         if (msg->devpath == NULL || msg->action == NULL) {
 645                 info("DEVPATH or ACTION missing, ignore message\n");
 646                 free(msg);
 647                 return NULL;
 648         }
 649         return msg;
 650 }
 651
 652 /* receive the udevd message from userspace */
 653 static void get_ctrl_msg(void)
 654 {
 655         struct udevd_ctrl_msg ctrl_msg;
 656         ssize_t size;
 657         struct msghdr smsg;
 658         struct cmsghdr *cmsg;
 659         struct iovec iov;
 660         struct ucred *cred;
 661         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 662         int *intval;
 663         char *pos;
 664
 665         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 666         iov.iov_base = &ctrl_msg;
 667         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 668
 669         memset(&smsg, 0x00, sizeof(struct msghdr));
 670         smsg.msg_iov = &iov;
 671         smsg.msg_iovlen = 1;
 672         smsg.msg_control = cred_msg;
 673         smsg.msg_controllen = sizeof(cred_msg);
 674
 675         size = recvmsg(udevd_sock, &smsg, 0);
 676         if (size <  0) {
 677                 if (errno != EINTR)
 678                         err("unable to receive user udevd message: %s\n", strerror(errno));
 679                 return;
 680         }
 681         cmsg = CMSG_FIRSTHDR(&smsg);
 682         cred = (struct ucred *) CMSG_DATA(cmsg);
 683
 684         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 685                 err("no sender credentials received, message ignored\n");
 686                 return;
 687         }
 688
 689         if (cred->uid != 0) {
 690                 err("sender uid=%i, message ignored\n", cred->uid);
 691                 return;
 692         }
 693
 694         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 695                 err("message magic '%s' doesn't match, ignore it\n", ctrl_msg.magic);
 696                 return;
 697         }
 698
 699         switch (ctrl_msg.type) {
 700         case UDEVD_CTRL_ENV:
 701                 pos = strchr(ctrl_msg.buf, '=');
 702                 if (pos == NULL) {
 703                         err("wrong key format '%s'\n", ctrl_msg.buf);
 704                         break;
 705                 }
 706                 pos[0] = '\0';
 707                 if (pos[1] == '\0') {
 708                         info("udevd message (ENV) received, unset '%s'\n", ctrl_msg.buf);
 709                         unsetenv(ctrl_msg.buf);
 710                 } else {
 711                         info("udevd message (ENV) received, set '%s=%s'\n", ctrl_msg.buf, &pos[1]);
 712                         setenv(ctrl_msg.buf, &pos[1], 1);
 713                 }
 714                 break;
 715         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 716                 info("udevd message (STOP_EXEC_QUEUE) received\n");
 717                 stop_exec_q = 1;
 718                 break;
 719         case UDEVD_CTRL_START_EXEC_QUEUE:
 720                 info("udevd message (START_EXEC_QUEUE) received\n");
 721                 stop_exec_q = 0;
 722                 msg_queue_manager();
 723                 break;
 724         case UDEVD_CTRL_SET_LOG_LEVEL:
 725                 intval = (int *) ctrl_msg.buf;
 726                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i\n", *intval);
 727                 udev_log_priority = *intval;
 728                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 729                 putenv(udev_log);
 730                 break;
 731         case UDEVD_CTRL_SET_MAX_CHILDS:
 732                 intval = (int *) ctrl_msg.buf;
 733                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i\n", *intval);
 734                 max_childs = *intval;
 735                 break;
 736         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 737                 intval = (int *) ctrl_msg.buf;
 738                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i\n", *intval);
 739                 max_childs_running = *intval;
 740                 break;
 741         case UDEVD_CTRL_RELOAD_RULES:
 742                 info("udevd message (RELOAD_RULES) received\n");
 743                 reload_config = 1;
 744                 break;
 745         default:
 746                 err("unknown control message type\n");
 747         }
 748 }
 749
 750 /* receive the kernel user event message and do some sanity checks */
 751 static struct udevd_uevent_msg *get_netlink_msg(void)
 752 {
 753         struct udevd_uevent_msg *msg;
 754         int bufpos;
 755         ssize_t size;
 756         static char buffer[UEVENT_BUFFER_SIZE+512];
 757         char *pos;
 758
 759         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 760         if (size <  0) {
 761                 if (errno != EINTR)
 762                         err("unable to receive kernel netlink message: %s\n", strerror(errno));
 763                 return NULL;
 764         }
 765
 766         if ((size_t)size > sizeof(buffer)-1)
 767                 size = sizeof(buffer)-1;
 768         buffer[size] = '\0';
 769         dbg("uevent_size=%zi\n", size);
 770
 771         /* start of event payload */
 772         bufpos = strlen(buffer)+1;
 773         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 774         if (msg == NULL)
 775                 return NULL;
 776
 777         /* validate message */
 778         pos = strchr(buffer, '@');
 779         if (pos == NULL) {
 780                 err("invalid uevent '%s'\n", buffer);
 781                 free(msg);
 782                 return NULL;
 783         }
 784         pos[0] = '\0';
 785
 786         if (msg->action == NULL) {
 787                 info("no ACTION in payload found, skip event '%s'\n", buffer);
 788                 free(msg);
 789                 return NULL;
 790         }
 791
 792         if (strcmp(msg->action, buffer) != 0) {
 793                 err("ACTION in payload does not match uevent, skip event '%s'\n", buffer);
 794                 free(msg);
 795                 return NULL;
 796         }
 797
 798         return msg;
 799 }
 800
 801 static void asmlinkage sig_handler(int signum)
 802 {
 803         switch (signum) {
 804                 case SIGINT:
 805                 case SIGTERM:
 806                         udev_exit = 1;
 807                         break;
 808                 case SIGCHLD:
 809                         /* set flag, then write to pipe if needed */
 810                         sigchilds_waiting = 1;
 811                         break;
 812                 case SIGHUP:
 813                         reload_config = 1;
 814                         break;
 815         }
 816
 817         /* write to pipe, which will wakeup select() in our mainloop */
 818         write(signal_pipe[WRITE_END], "", 1);
 819 }
 820
 821 static void udev_done(int pid, int exitstatus)
 822 {
 823         /* find msg associated with pid and delete it */
 824         struct udevd_uevent_msg *msg;
 825
 826         list_for_each_entry(msg, &running_list, node) {
 827                 if (msg->pid == pid) {
 828                         info("seq %llu, pid [%d] exit with %i, %ld seconds old\n", msg->seqnum, msg->pid,
 829                              exitstatus, time(NULL) - msg->queue_time);
 830                         msg->exitstatus = exitstatus;
 831                         msg_queue_delete(msg);
 832
 833                         /* there may be events waiting with the same devpath */
 834                         run_exec_q = 1;
 835                         return;
 836                 }
 837         }
 838 }
 839
 840 static void reap_sigchilds(void)
 841 {
 842         pid_t pid;
 843         int status;
 844
 845         while (1) {
 846                 pid = waitpid(-1, &status, WNOHANG);
 847                 if (pid <= 0)
 848                         break;
 849                 if (WIFEXITED(status))
 850                         status = WEXITSTATUS(status);
 851                 else if (WIFSIGNALED(status))
 852                         status = WTERMSIG(status) + 128;
 853                 else
 854                         status = 0;
 855                 udev_done(pid, status);
 856         }
 857 }
 858
 859 static int init_udevd_socket(void)
 860 {
 861         struct sockaddr_un saddr;
 862         socklen_t addrlen;
 863         const int feature_on = 1;
 864         int retval;
 865
 866         memset(&saddr, 0x00, sizeof(saddr));
 867         saddr.sun_family = AF_LOCAL;
 868         /* use abstract namespace for socket path */
 869         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 870         addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(&saddr.sun_path[1]);
 871
 872         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 873         if (udevd_sock == -1) {
 874                 err("error getting socket: %s\n", strerror(errno));
 875                 return -1;
 876         }
 877
 878         /* the bind takes care of ensuring only one copy running */
 879         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 880         if (retval < 0) {
 881                 err("bind failed: %s\n", strerror(errno));
 882                 close(udevd_sock);
 883                 udevd_sock = -1;
 884                 return -1;
 885         }
 886
 887         /* enable receiving of the sender credentials */
 888         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 889
 890         return 0;
 891 }
 892
 893 static int init_uevent_netlink_sock(void)
 894 {
 895         struct sockaddr_nl snl;
 896         const int buffersize = 16 * 1024 * 1024;
 897         int retval;
 898
 899         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 900         snl.nl_family = AF_NETLINK;
 901         snl.nl_pid = getpid();
 902         snl.nl_groups = 1;
 903
 904         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 905         if (uevent_netlink_sock == -1) {
 906                 err("error getting socket: %s\n", strerror(errno));
 907                 return -1;
 908         }
 909
 910         /* set receive buffersize */
 911         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 912
 913         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 914         if (retval < 0) {
 915                 err("bind failed: %s\n", strerror(errno));
 916                 close(uevent_netlink_sock);
 917                 uevent_netlink_sock = -1;
 918                 return -1;
 919         }
 920         return 0;
 921 }
 922
 923 static void export_initial_seqnum(void)
 924 {
 925         char filename[PATH_SIZE];
 926         int fd;
 927         char seqnum[32];
 928         ssize_t len = 0;
 929
 930         strlcpy(filename, sysfs_path, sizeof(filename));
 931         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 932         fd = open(filename, O_RDONLY);
 933         if (fd >= 0) {
 934                 len = read(fd, seqnum, sizeof(seqnum)-1);
 935                 close(fd);
 936         }
 937         if (len <= 0) {
 938                 strcpy(seqnum, "0\n");
 939                 len = 3;
 940         }
 941         strlcpy(filename, udev_root, sizeof(filename));
 942         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 943         create_path(filename);
 944         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 945         if (fd >= 0) {
 946                 write(fd, seqnum, len);
 947                 close(fd);
 948         }
 949 }
 950
 951 int main(int argc, char *argv[], char *envp[])
 952 {
 953         int retval;
 954         int fd;
 955         struct sigaction act;
 956         fd_set readfds;
 957         const char *value;
 958         int daemonize = 0;
 959         int option;
 960         static const struct option options[] = {
 961                 { "daemon", 0, NULL, 'd' },
 962                 { "debug-trace", 0, NULL, 't' },
 963                 { "debug", 0, NULL, 'D' },
 964                 { "help", 0, NULL, 'h' },
 965                 { "version", 0, NULL, 'V' },
 966                 {}
 967         };
 968         int rc = 1;
 969         int maxfd;
 970
 971         logging_init("udevd");
 972         udev_config_init();
 973         selinux_init();
 974         dbg("version %s\n", UDEV_VERSION);
 975
 976         while (1) {
 977                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 978                 if (option == -1)
 979                         break;
 980
 981                 switch (option) {
 982                 case 'd':
 983                         daemonize = 1;
 984                         break;
 985                 case 't':
 986                         debug_trace = 1;
 987                         break;
 988                 case 'D':
 989                         debug = 1;
 990                         if (udev_log_priority < LOG_INFO)
 991                                 udev_log_priority = LOG_INFO;
 992                         break;
 993                 case 'h':
 994                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
 995                         goto exit;
 996                 case 'V':
 997                         printf("%s\n", UDEV_VERSION);
 998                         goto exit;
 999                 default:
1000                         goto exit;
1001                 }
1002         }
1003
1004         if (getuid() != 0) {
1005                 fprintf(stderr, "root privileges required\n");
1006                 err("root privileges required\n");
1007                 goto exit;
1008         }
1009
1010         /* make sure std{in,out,err} fd's are in a sane state */
1011         fd = open("/dev/null", O_RDWR);
1012         if (fd < 0) {
1013                 fprintf(stderr, "cannot open /dev/null\n");
1014                 err("cannot open /dev/null\n");
1015         }
1016         if (fd > STDIN_FILENO)
1017                 dup2(fd, STDIN_FILENO);
1018         if (write(STDOUT_FILENO, 0, 0) < 0)
1019                 dup2(fd, STDOUT_FILENO);
1020         if (write(STDERR_FILENO, 0, 0) < 0)
1021                 dup2(fd, STDERR_FILENO);
1022
1023         /* init sockets to receive events */
1024         if (init_udevd_socket() < 0) {
1025                 if (errno == EADDRINUSE) {
1026                         fprintf(stderr, "another udev daemon already running\n");
1027                         err("another udev daemon already running\n");
1028                         rc = 1;
1029                 } else {
1030                         fprintf(stderr, "error initializing udevd socket\n");
1031                         err("error initializing udevd socket\n");
1032                         rc = 2;
1033                 }
1034                 goto exit;
1035         }
1036
1037         if (init_uevent_netlink_sock() < 0) {
1038                 fprintf(stderr, "error initializing netlink socket\n");
1039                 err("error initializing netlink socket\n");
1040                 rc = 3;
1041                 goto exit;
1042         }
1043
1044         /* setup signal handler pipe */
1045         retval = pipe(signal_pipe);
1046         if (retval < 0) {
1047                 err("error getting pipes: %s\n", strerror(errno));
1048                 goto exit;
1049         }
1050
1051         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1052         if (retval < 0) {
1053                 err("error fcntl on read pipe: %s\n", strerror(errno));
1054                 goto exit;
1055         }
1056         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1057         if (retval < 0) {
1058                 err("error fcntl on read pipe: %s\n", strerror(errno));
1059                 goto exit;
1060         }
1061
1062         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1063         if (retval < 0) {
1064                 err("error fcntl on write pipe: %s\n", strerror(errno));
1065                 goto exit;
1066         }
1067         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1068         if (retval < 0) {
1069                 err("error fcntl on write pipe: %s\n", strerror(errno));
1070                 goto exit;
1071         }
1072
1073         /* parse the rules and keep them in memory */
1074         sysfs_init();
1075         udev_rules_init(&rules, 1);
1076
1077         export_initial_seqnum();
1078
1079         if (daemonize) {
1080                 pid_t pid;
1081
1082                 pid = fork();
1083                 switch (pid) {
1084                 case 0:
1085                         dbg("daemonized fork running\n");
1086                         break;
1087                 case -1:
1088                         err("fork of daemon failed: %s\n", strerror(errno));
1089                         rc = 4;
1090                         goto exit;
1091                 default:
1092                         dbg("child [%u] running, parent exits\n", pid);
1093                         rc = 0;
1094                         goto exit;
1095                 }
1096         }
1097
1098         /* redirect std{out,err} fd's */
1099         if (!debug)
1100                 dup2(fd, STDOUT_FILENO);
1101         dup2(fd, STDERR_FILENO);
1102         if (fd > STDERR_FILENO)
1103                 close(fd);
1104
1105         /* set scheduling priority for the daemon */
1106         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1107
1108         chdir("/");
1109         umask(022);
1110
1111         /* become session leader */
1112         sid = setsid();
1113         dbg("our session is %d\n", sid);
1114
1115         /* OOM_DISABLE == -17 */
1116         fd = open("/proc/self/oom_adj", O_RDWR);
1117         if (fd < 0)
1118                 err("error disabling OOM: %s\n", strerror(errno));
1119         else {
1120                 write(fd, "-17", 3);
1121                 close(fd);
1122         }
1123
1124         fd = open("/dev/kmsg", O_WRONLY);
1125         if (fd > 0) {
1126                 const char *str = "<6>udevd version " UDEV_VERSION " started\n";
1127
1128                 write(fd, str, strlen(str));
1129                 close(fd);
1130         }
1131
1132         /* set signal handlers */
1133         memset(&act, 0x00, sizeof(struct sigaction));
1134         act.sa_handler = (void (*)(int)) sig_handler;
1135         sigemptyset(&act.sa_mask);
1136         act.sa_flags = SA_RESTART;
1137         sigaction(SIGINT, &act, NULL);
1138         sigaction(SIGTERM, &act, NULL);
1139         sigaction(SIGCHLD, &act, NULL);
1140         sigaction(SIGHUP, &act, NULL);
1141
1142         /* watch rules directory */
1143         inotify_fd = inotify_init();
1144         if (inotify_fd >= 0) {
1145                 char filename[PATH_MAX];
1146
1147                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1148
1149                 /* watch dynamic rules directory */
1150                 strlcpy(filename, udev_root, sizeof(filename));
1151                 strlcat(filename, "/"RULES_DYN_DIR, sizeof(filename));
1152                 inotify_add_watch(inotify_fd, filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1153         } else if (errno == ENOSYS)
1154                 err("the kernel does not support inotify, udevd can't monitor rules file changes\n");
1155         else
1156                 err("inotify_init failed: %s\n", strerror(errno));
1157
1158         /* maximum limit of forked childs */
1159         value = getenv("UDEVD_MAX_CHILDS");
1160         if (value)
1161                 max_childs = strtoul(value, NULL, 10);
1162         else {
1163                 int memsize = mem_size_mb();
1164                 if (memsize > 0)
1165                         max_childs = 128 + (memsize / 4);
1166                 else
1167                         max_childs = UDEVD_MAX_CHILDS;
1168         }
1169         info("initialize max_childs to %u\n", max_childs);
1170
1171         /* start to throttle forking if maximum number of _running_ childs is reached */
1172         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1173         if (value)
1174                 max_childs_running = strtoull(value, NULL, 10);
1175         else {
1176                 int cpus = cpu_count();
1177                 if (cpus > 0)
1178                         max_childs_running = 8 + (8 * cpus);
1179                 else
1180                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1181         }
1182         info("initialize max_childs_running to %u\n", max_childs_running);
1183
1184         /* clear environment for forked event processes */
1185         clearenv();
1186
1187         /* export log_priority , as called programs may want to follow that setting */
1188         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1189         putenv(udev_log);
1190         if (debug_trace)
1191                 putenv("DEBUG=1");
1192
1193         maxfd = udevd_sock;
1194         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1195         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1196         maxfd = UDEV_MAX(maxfd, inotify_fd);
1197
1198         while (!udev_exit) {
1199                 struct udevd_uevent_msg *msg;
1200                 int fdcount;
1201
1202                 FD_ZERO(&readfds);
1203                 FD_SET(signal_pipe[READ_END], &readfds);
1204                 FD_SET(udevd_sock, &readfds);
1205                 FD_SET(uevent_netlink_sock, &readfds);
1206                 if (inotify_fd >= 0)
1207                         FD_SET(inotify_fd, &readfds);
1208
1209                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1210                 if (fdcount < 0) {
1211                         if (errno != EINTR)
1212                                 err("error in select: %s\n", strerror(errno));
1213                         continue;
1214                 }
1215
1216                 /* get control message */
1217                 if (FD_ISSET(udevd_sock, &readfds))
1218                         get_ctrl_msg();
1219
1220                 /* get netlink message */
1221                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1222                         msg = get_netlink_msg();
1223                         if (msg)
1224                                 msg_queue_insert(msg);
1225                 }
1226
1227                 /* received a signal, clear our notification pipe */
1228                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1229                         char buf[256];
1230
1231                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1232                 }
1233
1234                 /* rules directory inotify watch */
1235                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1236                         int nbytes;
1237
1238                         /* discard all possible events, we can just reload the config */
1239                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1240                                 char *buf;
1241
1242                                 reload_config = 1;
1243                                 buf = malloc(nbytes);
1244                                 if (buf == NULL) {
1245                                         err("error getting buffer for inotify, disable watching\n");
1246                                         close(inotify_fd);
1247                                         inotify_fd = -1;
1248                                 }
1249                                 read(inotify_fd, buf, nbytes);
1250                                 free(buf);
1251                         }
1252                 }
1253
1254                 /* rules changed, set by inotify or a HUP signal */
1255                 if (reload_config) {
1256                         reload_config = 0;
1257                         udev_rules_cleanup(&rules);
1258                         udev_rules_init(&rules, 1);
1259                 }
1260
1261                 /* forked child has returned */
1262                 if (sigchilds_waiting) {
1263                         sigchilds_waiting = 0;
1264                         reap_sigchilds();
1265                 }
1266
1267                 if (run_exec_q) {
1268                         run_exec_q = 0;
1269                         if (!stop_exec_q)
1270                                 msg_queue_manager();
1271                 }
1272         }
1273         rc = 0;
1274
1275 exit:
1276         udev_rules_cleanup(&rules);
1277         sysfs_cleanup();
1278         selinux_exit();
1279
1280         if (signal_pipe[READ_END] >= 0)
1281                 close(signal_pipe[READ_END]);
1282         if (signal_pipe[WRITE_END] >= 0)
1283                 close(signal_pipe[WRITE_END]);
1284
1285         if (udevd_sock >= 0)
1286                 close(udevd_sock);
1287         if (inotify_fd >= 0)
1288                 close(inotify_fd);
1289         if (uevent_netlink_sock >= 0)
1290                 close(uevent_netlink_sock);
1291
1292         logging_close();
1293
1294         return rc;
1295 }