udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include "config.h"
  21
  22 #include <stddef.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <dirent.h>
  31 #include <fcntl.h>
  32 #include <syslog.h>
  33 #include <time.h>
  34 #include <getopt.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44 #ifdef HAVE_INOTIFY
  45 #include <sys/inotify.h>
  46 #endif
  47
  48 #include "udev.h"
  49 #include "udev_rules.h"
  50 #include "udevd.h"
  51 #include "udev_selinux.h"
  52
  53 static int debug_trace;
  54 static int debug;
  55
  56 static struct udev_rules rules;
  57 static int udevd_sock = -1;
  58 static int uevent_netlink_sock = -1;
  59 static int inotify_fd = -1;
  60 static pid_t sid;
  61
  62 static int signal_pipe[2] = {-1, -1};
  63 static volatile int sigchilds_waiting;
  64 static volatile int udev_exit;
  65 static volatile int reload_config;
  66 static int run_exec_q;
  67 static int stop_exec_q;
  68 static int max_childs;
  69 static int max_childs_running;
  70 static char udev_log[32];
  71
  72 static LIST_HEAD(exec_list);
  73 static LIST_HEAD(running_list);
  74
  75
  76 #ifdef USE_LOG
  77 void log_message(int priority, const char *format, ...)
  78 {
  79         va_list args;
  80
  81         if (priority > udev_log_priority)
  82                 return;
  83
  84         va_start(args, format);
  85         if (debug) {
  86                 printf("[%d] ", (int) getpid());
  87                 vprintf(format, args);
  88         } else
  89                 vsyslog(priority, format, args);
  90         va_end(args);
  91 }
  92
  93 #endif
  94
  95 static void asmlinkage udev_event_sig_handler(int signum)
  96 {
  97         if (signum == SIGALRM)
  98                 exit(1);
  99 }
 100
 101 static int udev_event_process(struct udevd_uevent_msg *msg)
 102 {
 103         struct sigaction act;
 104         struct udevice *udev;
 105         int i;
 106         int retval;
 107
 108         /* set signal handlers */
 109         memset(&act, 0x00, sizeof(act));
 110         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 111         sigemptyset (&act.sa_mask);
 112         act.sa_flags = 0;
 113         sigaction(SIGALRM, &act, NULL);
 114
 115         /* reset to default */
 116         act.sa_handler = SIG_DFL;
 117         sigaction(SIGINT, &act, NULL);
 118         sigaction(SIGTERM, &act, NULL);
 119         sigaction(SIGCHLD, &act, NULL);
 120         sigaction(SIGHUP, &act, NULL);
 121
 122         /* trigger timeout to prevent hanging processes */
 123         alarm(UDEV_EVENT_TIMEOUT);
 124
 125         /* reconstruct event environment from message */
 126         for (i = 0; msg->envp[i]; i++)
 127                 putenv(msg->envp[i]);
 128
 129         udev = udev_device_init(NULL);
 130         if (udev == NULL)
 131                 return -1;
 132         strlcpy(udev->action, msg->action, sizeof(udev->action));
 133         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 134         udev->devpath_old = msg->devpath_old;
 135         udev->devt = msg->devt;
 136
 137         retval = udev_device_event(&rules, udev);
 138
 139         /* rules may change/disable the timeout */
 140         if (udev->event_timeout >= 0)
 141                 alarm(udev->event_timeout);
 142
 143         /* run programs collected by RUN-key*/
 144         if (retval == 0 && !udev->ignore_device && udev_run)
 145                 retval = udev_rules_run(udev);
 146
 147         udev_device_cleanup(udev);
 148         return retval;
 149 }
 150
 151 enum event_state {
 152         EVENT_QUEUED,
 153         EVENT_FINISHED,
 154         EVENT_FAILED,
 155 };
 156
 157 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 158 {
 159         char filename[PATH_SIZE];
 160         char filename_failed[PATH_SIZE];
 161         size_t start;
 162
 163         /* location of queue file */
 164         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu", udev_root, msg->seqnum);
 165
 166         /* location of failed file */
 167         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 168         strlcat(filename_failed, "/", sizeof(filename_failed));
 169         start = strlcat(filename_failed, ".udev/failed/", sizeof(filename_failed));
 170         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 171         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 172
 173         switch (state) {
 174         case EVENT_QUEUED:
 175                 unlink(filename_failed);
 176                 delete_path(filename_failed);
 177
 178                 create_path(filename);
 179                 selinux_setfscreatecon(filename, NULL, S_IFLNK);
 180                 symlink(msg->devpath, filename);
 181                 selinux_resetfscreatecon();
 182                 break;
 183         case EVENT_FINISHED:
 184                 if (msg->devpath_old != NULL) {
 185                         /* "move" event - rename failed file to current name, do not delete failed */
 186                         char filename_failed_old[PATH_SIZE];
 187
 188                         strlcpy(filename_failed_old, udev_root, sizeof(filename_failed_old));
 189                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 190                         start = strlcat(filename_failed_old, ".udev/failed/", sizeof(filename_failed_old));
 191                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 192                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 193
 194                         if (rename(filename_failed_old, filename_failed) == 0)
 195                                 info("renamed devpath, moved failed state of '%s' to %s'\n",
 196                                      msg->devpath_old, msg->devpath);
 197                 } else {
 198                         unlink(filename_failed);
 199                         delete_path(filename_failed);
 200                 }
 201
 202                 unlink(filename);
 203                 delete_path(filename);
 204                 break;
 205         case EVENT_FAILED:
 206                 /* move failed event to the failed directory */
 207                 create_path(filename_failed);
 208                 rename(filename, filename_failed);
 209
 210                 /* clean up possibly empty queue directory */
 211                 delete_path(filename);
 212                 break;
 213         }
 214
 215         return;
 216 }
 217
 218 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 219 {
 220         list_del(&msg->node);
 221
 222         /* mark as failed, if "add" event returns non-zero */
 223         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 224                 export_event_state(msg, EVENT_FAILED);
 225         else
 226                 export_event_state(msg, EVENT_FINISHED);
 227
 228         free(msg);
 229 }
 230
 231 static void udev_event_run(struct udevd_uevent_msg *msg)
 232 {
 233         pid_t pid;
 234         int retval;
 235
 236         pid = fork();
 237         switch (pid) {
 238         case 0:
 239                 /* child */
 240                 close(uevent_netlink_sock);
 241                 close(udevd_sock);
 242                 if (inotify_fd >= 0)
 243                         close(inotify_fd);
 244                 close(signal_pipe[READ_END]);
 245                 close(signal_pipe[WRITE_END]);
 246                 logging_close();
 247
 248                 logging_init("udevd-event");
 249                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 250
 251                 retval = udev_event_process(msg);
 252                 info("seq %llu finished with %i\n", msg->seqnum, retval);
 253
 254                 logging_close();
 255                 if (retval)
 256                         exit(1);
 257                 exit(0);
 258         case -1:
 259                 err("fork of child failed: %s\n", strerror(errno));
 260                 msg_queue_delete(msg);
 261                 break;
 262         default:
 263                 /* get SIGCHLD in main loop */
 264                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 265                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 266                 msg->pid = pid;
 267         }
 268 }
 269
 270 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 271 {
 272         char filename[PATH_SIZE];
 273         int fd;
 274
 275         msg->queue_time = time(NULL);
 276
 277         export_event_state(msg, EVENT_QUEUED);
 278         info("seq %llu queued, '%s' '%s'\n", msg->seqnum, msg->action, msg->subsystem);
 279
 280         strlcpy(filename, udev_root, sizeof(filename));
 281         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 282         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 283         if (fd >= 0) {
 284                 char str[32];
 285                 int len;
 286
 287                 len = sprintf(str, "%llu\n", msg->seqnum);
 288                 write(fd, str, len);
 289                 close(fd);
 290         }
 291
 292         /* run one event after the other in debug mode */
 293         if (debug_trace) {
 294                 list_add_tail(&msg->node, &running_list);
 295                 udev_event_run(msg);
 296                 waitpid(msg->pid, NULL, 0);
 297                 msg_queue_delete(msg);
 298                 return;
 299         }
 300
 301         /* run all events with a timeout set immediately */
 302         if (msg->timeout != 0) {
 303                 list_add_tail(&msg->node, &running_list);
 304                 udev_event_run(msg);
 305                 return;
 306         }
 307
 308         list_add_tail(&msg->node, &exec_list);
 309         run_exec_q = 1;
 310 }
 311
 312 static int mem_size_mb(void)
 313 {
 314         FILE* f;
 315         char buf[4096];
 316         long int memsize = -1;
 317
 318         f = fopen("/proc/meminfo", "r");
 319         if (f == NULL)
 320                 return -1;
 321
 322         while (fgets(buf, sizeof(buf), f) != NULL) {
 323                 long int value;
 324
 325                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 326                         memsize = value / 1024;
 327                         break;
 328                 }
 329         }
 330
 331         fclose(f);
 332         return memsize;
 333 }
 334
 335 static int cpu_count(void)
 336 {
 337         FILE* f;
 338         char buf[4096];
 339         int count = 0;
 340
 341         f = fopen("/proc/stat", "r");
 342         if (f == NULL)
 343                 return -1;
 344
 345         while (fgets(buf, sizeof(buf), f) != NULL) {
 346                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 347                         count++;
 348         }
 349
 350         fclose(f);
 351         if (count == 0)
 352                 return -1;
 353         return count;
 354 }
 355
 356 static int running_processes(void)
 357 {
 358         FILE* f;
 359         char buf[4096];
 360         int running = -1;
 361
 362         f = fopen("/proc/stat", "r");
 363         if (f == NULL)
 364                 return -1;
 365
 366         while (fgets(buf, sizeof(buf), f) != NULL) {
 367                 int value;
 368
 369                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 370                         running = value;
 371                         break;
 372                 }
 373         }
 374
 375         fclose(f);
 376         return running;
 377 }
 378
 379 /* return the number of process es in our session, count only until limit */
 380 static int running_processes_in_session(pid_t session, int limit)
 381 {
 382         DIR *dir;
 383         struct dirent *dent;
 384         int running = 0;
 385
 386         dir = opendir("/proc");
 387         if (!dir)
 388                 return -1;
 389
 390         /* read process info from /proc */
 391         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 392                 int f;
 393                 char procdir[64];
 394                 char line[256];
 395                 const char *pos;
 396                 char state;
 397                 pid_t ppid, pgrp, sess;
 398                 int len;
 399
 400                 if (!isdigit(dent->d_name[0]))
 401                         continue;
 402
 403                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 404                 procdir[sizeof(procdir)-1] = '\0';
 405
 406                 f = open(procdir, O_RDONLY);
 407                 if (f == -1)
 408                         continue;
 409
 410                 len = read(f, line, sizeof(line)-1);
 411                 close(f);
 412
 413                 if (len <= 0)
 414                         continue;
 415                 else
 416                         line[len] = '\0';
 417
 418                 /* skip ugly program name */
 419                 pos = strrchr(line, ')') + 2;
 420                 if (pos == NULL)
 421                         continue;
 422
 423                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 424                         continue;
 425
 426                 /* count only processes in our session */
 427                 if (sess != session)
 428                         continue;
 429
 430                 /* count only running, no sleeping processes */
 431                 if (state != 'R')
 432                         continue;
 433
 434                 running++;
 435                 if (limit > 0 && running >= limit)
 436                         break;
 437         }
 438         closedir(dir);
 439
 440         return running;
 441 }
 442
 443 static int compare_devpath(const char *running, const char *waiting)
 444 {
 445         int i;
 446
 447         for (i = 0; i < PATH_SIZE; i++) {
 448                 /* identical device event found */
 449                 if (running[i] == '\0' && waiting[i] == '\0')
 450                         return 1;
 451
 452                 /* parent device event found */
 453                 if (running[i] == '\0' && waiting[i] == '/')
 454                         return 2;
 455
 456                 /* child device event found */
 457                 if (running[i] == '/' && waiting[i] == '\0')
 458                         return 3;
 459
 460                 /* no matching event */
 461                 if (running[i] != waiting[i])
 462                         break;
 463         }
 464
 465         return 0;
 466 }
 467
 468 /* lookup event for identical, parent, child, or physical device */
 469 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 470 {
 471         struct udevd_uevent_msg *loop_msg;
 472         int childs_count = 0;
 473
 474         /* check exec-queue which may still contain delayed events we depend on */
 475         list_for_each_entry(loop_msg, &exec_list, node) {
 476                 /* skip ourself and all later events */
 477                 if (loop_msg->seqnum >= msg->seqnum)
 478                         break;
 479
 480                 /* check our old name */
 481                 if (msg->devpath_old != NULL)
 482                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 483                                 return 2;
 484
 485                 /* check identical, parent, or child device event */
 486                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 487                         dbg("%llu, device event still pending %llu (%s)\n",
 488                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 489                         return 3;
 490                 }
 491
 492                 /* check for our major:minor number */
 493                 if (msg->devt && loop_msg->devt == msg->devt &&
 494                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 495                         dbg("%llu, device event still pending %llu (%d:%d)\n", msg->seqnum,
 496                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 497                         return 4;
 498                 }
 499
 500                 /* check physical device event (special case of parent) */
 501                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 502                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 503                                 dbg("%llu, physical device event still pending %llu (%s)\n",
 504                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 505                                 return 5;
 506                         }
 507         }
 508
 509         /* check run queue for still running events */
 510         list_for_each_entry(loop_msg, &running_list, node) {
 511                 if (limit && childs_count++ > limit) {
 512                         dbg("%llu, maximum number (%i) of childs reached\n", msg->seqnum, childs_count);
 513                         return 1;
 514                 }
 515
 516                 /* check our old name */
 517                 if (msg->devpath_old != NULL)
 518                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 519                                 return 2;
 520
 521                 /* check identical, parent, or child device event */
 522                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 523                         dbg("%llu, device event still running %llu (%s)\n",
 524                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 525                         return 3;
 526                 }
 527
 528                 /* check for our major:minor number */
 529                 if (msg->devt && loop_msg->devt == msg->devt &&
 530                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 531                         dbg("%llu, device event still running %llu (%d:%d)\n", msg->seqnum,
 532                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 533                         return 4;
 534                 }
 535
 536                 /* check physical device event (special case of parent) */
 537                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 538                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 539                                 dbg("%llu, physical device event still running %llu (%s)\n",
 540                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 541                                 return 5;
 542                         }
 543         }
 544         return 0;
 545 }
 546
 547 /* serializes events for the identical and parent and child devices */
 548 static void msg_queue_manager(void)
 549 {
 550         struct udevd_uevent_msg *loop_msg;
 551         struct udevd_uevent_msg *tmp_msg;
 552         int running;
 553
 554         if (list_empty(&exec_list))
 555                 return;
 556
 557         running = running_processes();
 558         dbg("%d processes runnning on system\n", running);
 559         if (running < 0)
 560                 running = max_childs_running;
 561
 562         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 563                 /* check running processes in our session and possibly throttle */
 564                 if (running >= max_childs_running) {
 565                         running = running_processes_in_session(sid, max_childs_running+10);
 566                         dbg("at least %d processes running in session\n", running);
 567                         if (running >= max_childs_running) {
 568                                 dbg("delay seq %llu, too many processes already running\n", loop_msg->seqnum);
 569                                 return;
 570                         }
 571                 }
 572
 573                 /* serialize and wait for parent or child events */
 574                 if (devpath_busy(loop_msg, max_childs) != 0) {
 575                         dbg("delay seq %llu (%s)\n", loop_msg->seqnum, loop_msg->devpath);
 576                         continue;
 577                 }
 578
 579                 /* move event to run list */
 580                 list_move_tail(&loop_msg->node, &running_list);
 581                 udev_event_run(loop_msg);
 582                 running++;
 583                 dbg("moved seq %llu to running list\n", loop_msg->seqnum);
 584         }
 585 }
 586
 587 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 588 {
 589         int bufpos;
 590         int i;
 591         struct udevd_uevent_msg *msg;
 592         char *physdevdriver_key = NULL;
 593         int maj = 0;
 594         int min = 0;
 595
 596         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 597         if (msg == NULL)
 598                 return NULL;
 599         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 600
 601         /* copy environment buffer and reconstruct envp */
 602         memcpy(msg->envbuf, buf, buf_size);
 603         bufpos = 0;
 604         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 605                 int keylen;
 606                 char *key;
 607
 608                 key = &msg->envbuf[bufpos];
 609                 keylen = strlen(key);
 610                 msg->envp[i] = key;
 611                 bufpos += keylen + 1;
 612                 dbg("add '%s' to msg.envp[%i]\n", msg->envp[i], i);
 613
 614                 /* remember some keys for further processing */
 615                 if (strncmp(key, "ACTION=", 7) == 0)
 616                         msg->action = &key[7];
 617                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 618                         msg->devpath = &key[8];
 619                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 620                         msg->subsystem = &key[10];
 621                 else if (strncmp(key, "DRIVER=", 7) == 0)
 622                         msg->driver = &key[7];
 623                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 624                         msg->seqnum = strtoull(&key[7], NULL, 10);
 625                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 626                         msg->devpath_old = &key[12];
 627                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 628                         msg->physdevpath = &key[12];
 629                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 630                         physdevdriver_key = key;
 631                 else if (strncmp(key, "MAJOR=", 6) == 0)
 632                         maj = strtoull(&key[6], NULL, 10);
 633                 else if (strncmp(key, "MINOR=", 6) == 0)
 634                         min = strtoull(&key[6], NULL, 10);
 635                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 636                         msg->timeout = strtoull(&key[8], NULL, 10);
 637         }
 638         msg->devt = makedev(maj, min);
 639         msg->envp[i++] = "UDEVD_EVENT=1";
 640
 641         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 642                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 643                 msg->envp[i++] = &physdevdriver_key[7];
 644                 msg->driver = &physdevdriver_key[14];
 645         }
 646
 647         msg->envp[i] = NULL;
 648
 649         if (msg->devpath == NULL || msg->action == NULL) {
 650                 info("DEVPATH or ACTION missing, ignore message\n");
 651                 free(msg);
 652                 return NULL;
 653         }
 654         return msg;
 655 }
 656
 657 /* receive the udevd message from userspace */
 658 static void get_ctrl_msg(void)
 659 {
 660         struct udevd_ctrl_msg ctrl_msg;
 661         ssize_t size;
 662         struct msghdr smsg;
 663         struct cmsghdr *cmsg;
 664         struct iovec iov;
 665         struct ucred *cred;
 666         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 667         int *intval;
 668         char *pos;
 669
 670         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 671         iov.iov_base = &ctrl_msg;
 672         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 673
 674         memset(&smsg, 0x00, sizeof(struct msghdr));
 675         smsg.msg_iov = &iov;
 676         smsg.msg_iovlen = 1;
 677         smsg.msg_control = cred_msg;
 678         smsg.msg_controllen = sizeof(cred_msg);
 679
 680         size = recvmsg(udevd_sock, &smsg, 0);
 681         if (size <  0) {
 682                 if (errno != EINTR)
 683                         err("unable to receive user udevd message: %s\n", strerror(errno));
 684                 return;
 685         }
 686         cmsg = CMSG_FIRSTHDR(&smsg);
 687         cred = (struct ucred *) CMSG_DATA(cmsg);
 688
 689         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 690                 err("no sender credentials received, message ignored\n");
 691                 return;
 692         }
 693
 694         if (cred->uid != 0) {
 695                 err("sender uid=%i, message ignored\n", cred->uid);
 696                 return;
 697         }
 698
 699         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 700                 err("message magic '%s' doesn't match, ignore it\n", ctrl_msg.magic);
 701                 return;
 702         }
 703
 704         switch (ctrl_msg.type) {
 705         case UDEVD_CTRL_ENV:
 706                 pos = strchr(ctrl_msg.buf, '=');
 707                 if (pos == NULL) {
 708                         err("wrong key format '%s'\n", ctrl_msg.buf);
 709                         break;
 710                 }
 711                 pos[0] = '\0';
 712                 if (pos[1] == '\0') {
 713                         info("udevd message (ENV) received, unset '%s'\n", ctrl_msg.buf);
 714                         unsetenv(ctrl_msg.buf);
 715                 } else {
 716                         info("udevd message (ENV) received, set '%s=%s'\n", ctrl_msg.buf, &pos[1]);
 717                         setenv(ctrl_msg.buf, &pos[1], 1);
 718                 }
 719                 break;
 720         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 721                 info("udevd message (STOP_EXEC_QUEUE) received\n");
 722                 stop_exec_q = 1;
 723                 break;
 724         case UDEVD_CTRL_START_EXEC_QUEUE:
 725                 info("udevd message (START_EXEC_QUEUE) received\n");
 726                 stop_exec_q = 0;
 727                 msg_queue_manager();
 728                 break;
 729         case UDEVD_CTRL_SET_LOG_LEVEL:
 730                 intval = (int *) ctrl_msg.buf;
 731                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i\n", *intval);
 732                 udev_log_priority = *intval;
 733                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 734                 putenv(udev_log);
 735                 break;
 736         case UDEVD_CTRL_SET_MAX_CHILDS:
 737                 intval = (int *) ctrl_msg.buf;
 738                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i\n", *intval);
 739                 max_childs = *intval;
 740                 break;
 741         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 742                 intval = (int *) ctrl_msg.buf;
 743                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i\n", *intval);
 744                 max_childs_running = *intval;
 745                 break;
 746         case UDEVD_CTRL_RELOAD_RULES:
 747                 info("udevd message (RELOAD_RULES) received\n");
 748                 reload_config = 1;
 749                 break;
 750         default:
 751                 err("unknown control message type\n");
 752         }
 753 }
 754
 755 /* receive the kernel user event message and do some sanity checks */
 756 static struct udevd_uevent_msg *get_netlink_msg(void)
 757 {
 758         struct udevd_uevent_msg *msg;
 759         int bufpos;
 760         ssize_t size;
 761         static char buffer[UEVENT_BUFFER_SIZE+512];
 762         char *pos;
 763
 764         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 765         if (size <  0) {
 766                 if (errno != EINTR)
 767                         err("unable to receive kernel netlink message: %s\n", strerror(errno));
 768                 return NULL;
 769         }
 770
 771         if ((size_t)size > sizeof(buffer)-1)
 772                 size = sizeof(buffer)-1;
 773         buffer[size] = '\0';
 774         dbg("uevent_size=%zi\n", size);
 775
 776         /* start of event payload */
 777         bufpos = strlen(buffer)+1;
 778         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 779         if (msg == NULL)
 780                 return NULL;
 781
 782         /* validate message */
 783         pos = strchr(buffer, '@');
 784         if (pos == NULL) {
 785                 err("invalid uevent '%s'\n", buffer);
 786                 free(msg);
 787                 return NULL;
 788         }
 789         pos[0] = '\0';
 790
 791         if (msg->action == NULL) {
 792                 info("no ACTION in payload found, skip event '%s'\n", buffer);
 793                 free(msg);
 794                 return NULL;
 795         }
 796
 797         if (strcmp(msg->action, buffer) != 0) {
 798                 err("ACTION in payload does not match uevent, skip event '%s'\n", buffer);
 799                 free(msg);
 800                 return NULL;
 801         }
 802
 803         return msg;
 804 }
 805
 806 static void asmlinkage sig_handler(int signum)
 807 {
 808         switch (signum) {
 809                 case SIGINT:
 810                 case SIGTERM:
 811                         udev_exit = 1;
 812                         break;
 813                 case SIGCHLD:
 814                         /* set flag, then write to pipe if needed */
 815                         sigchilds_waiting = 1;
 816                         break;
 817                 case SIGHUP:
 818                         reload_config = 1;
 819                         break;
 820         }
 821
 822         /* write to pipe, which will wakeup select() in our mainloop */
 823         write(signal_pipe[WRITE_END], "", 1);
 824 }
 825
 826 static void udev_done(int pid, int exitstatus)
 827 {
 828         /* find msg associated with pid and delete it */
 829         struct udevd_uevent_msg *msg;
 830
 831         list_for_each_entry(msg, &running_list, node) {
 832                 if (msg->pid == pid) {
 833                         info("seq %llu, pid [%d] exit with %i, %ld seconds old\n", msg->seqnum, msg->pid,
 834                              exitstatus, time(NULL) - msg->queue_time);
 835                         msg->exitstatus = exitstatus;
 836                         msg_queue_delete(msg);
 837
 838                         /* there may be events waiting with the same devpath */
 839                         run_exec_q = 1;
 840                         return;
 841                 }
 842         }
 843 }
 844
 845 static void reap_sigchilds(void)
 846 {
 847         pid_t pid;
 848         int status;
 849
 850         while (1) {
 851                 pid = waitpid(-1, &status, WNOHANG);
 852                 if (pid <= 0)
 853                         break;
 854                 if (WIFEXITED(status))
 855                         status = WEXITSTATUS(status);
 856                 else if (WIFSIGNALED(status))
 857                         status = WTERMSIG(status) + 128;
 858                 else
 859                         status = 0;
 860                 udev_done(pid, status);
 861         }
 862 }
 863
 864 static int init_udevd_socket(void)
 865 {
 866         struct sockaddr_un saddr;
 867         socklen_t addrlen;
 868         const int feature_on = 1;
 869         int retval;
 870
 871         memset(&saddr, 0x00, sizeof(saddr));
 872         saddr.sun_family = AF_LOCAL;
 873         /* use abstract namespace for socket path */
 874         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 875         addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(&saddr.sun_path[1]);
 876
 877         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 878         if (udevd_sock == -1) {
 879                 err("error getting socket: %s\n", strerror(errno));
 880                 return -1;
 881         }
 882
 883         /* the bind takes care of ensuring only one copy running */
 884         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 885         if (retval < 0) {
 886                 err("bind failed: %s\n", strerror(errno));
 887                 close(udevd_sock);
 888                 udevd_sock = -1;
 889                 return -1;
 890         }
 891
 892         /* enable receiving of the sender credentials */
 893         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 894
 895         return 0;
 896 }
 897
 898 static int init_uevent_netlink_sock(void)
 899 {
 900         struct sockaddr_nl snl;
 901         const int buffersize = 16 * 1024 * 1024;
 902         int retval;
 903
 904         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 905         snl.nl_family = AF_NETLINK;
 906         snl.nl_pid = getpid();
 907         snl.nl_groups = 1;
 908
 909         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 910         if (uevent_netlink_sock == -1) {
 911                 err("error getting socket: %s\n", strerror(errno));
 912                 return -1;
 913         }
 914
 915         /* set receive buffersize */
 916         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 917
 918         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 919         if (retval < 0) {
 920                 err("bind failed: %s\n", strerror(errno));
 921                 close(uevent_netlink_sock);
 922                 uevent_netlink_sock = -1;
 923                 return -1;
 924         }
 925         return 0;
 926 }
 927
 928 static void export_initial_seqnum(void)
 929 {
 930         char filename[PATH_SIZE];
 931         int fd;
 932         char seqnum[32];
 933         ssize_t len = 0;
 934
 935         strlcpy(filename, sysfs_path, sizeof(filename));
 936         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 937         fd = open(filename, O_RDONLY);
 938         if (fd >= 0) {
 939                 len = read(fd, seqnum, sizeof(seqnum)-1);
 940                 close(fd);
 941         }
 942         if (len <= 0) {
 943                 strcpy(seqnum, "0\n");
 944                 len = 3;
 945         }
 946         strlcpy(filename, udev_root, sizeof(filename));
 947         strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 948         create_path(filename);
 949         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 950         if (fd >= 0) {
 951                 write(fd, seqnum, len);
 952                 close(fd);
 953         }
 954 }
 955
 956 int main(int argc, char *argv[], char *envp[])
 957 {
 958         int retval;
 959         int fd;
 960         struct sigaction act;
 961         fd_set readfds;
 962         const char *value;
 963         int daemonize = 0;
 964         int option;
 965         static const struct option options[] = {
 966                 { "daemon", 0, NULL, 'd' },
 967                 { "debug-trace", 0, NULL, 't' },
 968                 { "debug", 0, NULL, 'D' },
 969                 { "help", 0, NULL, 'h' },
 970                 { "version", 0, NULL, 'V' },
 971                 {}
 972         };
 973         int rc = 1;
 974         int maxfd;
 975
 976         logging_init("udevd");
 977         udev_config_init();
 978         selinux_init();
 979         dbg("version %s\n", VERSION);
 980
 981         while (1) {
 982                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 983                 if (option == -1)
 984                         break;
 985
 986                 switch (option) {
 987                 case 'd':
 988                         daemonize = 1;
 989                         break;
 990                 case 't':
 991                         debug_trace = 1;
 992                         break;
 993                 case 'D':
 994                         debug = 1;
 995                         if (udev_log_priority < LOG_INFO)
 996                                 udev_log_priority = LOG_INFO;
 997                         break;
 998                 case 'h':
 999                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
1000                         goto exit;
1001                 case 'V':
1002                         printf("%s\n", VERSION);
1003                         goto exit;
1004                 default:
1005                         goto exit;
1006                 }
1007         }
1008
1009         if (getuid() != 0) {
1010                 fprintf(stderr, "root privileges required\n");
1011                 err("root privileges required\n");
1012                 goto exit;
1013         }
1014
1015         /* make sure std{in,out,err} fd's are in a sane state */
1016         fd = open("/dev/null", O_RDWR);
1017         if (fd < 0) {
1018                 fprintf(stderr, "cannot open /dev/null\n");
1019                 err("cannot open /dev/null\n");
1020         }
1021         if (fd > STDIN_FILENO)
1022                 dup2(fd, STDIN_FILENO);
1023         if (write(STDOUT_FILENO, 0, 0) < 0)
1024                 dup2(fd, STDOUT_FILENO);
1025         if (write(STDERR_FILENO, 0, 0) < 0)
1026                 dup2(fd, STDERR_FILENO);
1027
1028         /* init sockets to receive events */
1029         if (init_udevd_socket() < 0) {
1030                 if (errno == EADDRINUSE) {
1031                         fprintf(stderr, "another udev daemon already running\n");
1032                         err("another udev daemon already running\n");
1033                         rc = 1;
1034                 } else {
1035                         fprintf(stderr, "error initializing udevd socket\n");
1036                         err("error initializing udevd socket\n");
1037                         rc = 2;
1038                 }
1039                 goto exit;
1040         }
1041
1042         if (init_uevent_netlink_sock() < 0) {
1043                 fprintf(stderr, "error initializing netlink socket\n");
1044                 err("error initializing netlink socket\n");
1045                 rc = 3;
1046                 goto exit;
1047         }
1048
1049         /* setup signal handler pipe */
1050         retval = pipe(signal_pipe);
1051         if (retval < 0) {
1052                 err("error getting pipes: %s\n", strerror(errno));
1053                 goto exit;
1054         }
1055
1056         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1057         if (retval < 0) {
1058                 err("error fcntl on read pipe: %s\n", strerror(errno));
1059                 goto exit;
1060         }
1061         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1062         if (retval < 0) {
1063                 err("error fcntl on read pipe: %s\n", strerror(errno));
1064                 goto exit;
1065         }
1066
1067         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1068         if (retval < 0) {
1069                 err("error fcntl on write pipe: %s\n", strerror(errno));
1070                 goto exit;
1071         }
1072         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1073         if (retval < 0) {
1074                 err("error fcntl on write pipe: %s\n", strerror(errno));
1075                 goto exit;
1076         }
1077
1078         /* parse the rules and keep them in memory */
1079         sysfs_init();
1080         udev_rules_init(&rules, 1);
1081
1082         export_initial_seqnum();
1083
1084         if (daemonize) {
1085                 pid_t pid;
1086
1087                 pid = fork();
1088                 switch (pid) {
1089                 case 0:
1090                         dbg("daemonized fork running\n");
1091                         break;
1092                 case -1:
1093                         err("fork of daemon failed: %s\n", strerror(errno));
1094                         rc = 4;
1095                         goto exit;
1096                 default:
1097                         dbg("child [%u] running, parent exits\n", pid);
1098                         rc = 0;
1099                         goto exit;
1100                 }
1101         }
1102
1103         /* redirect std{out,err} fd's */
1104         if (!debug)
1105                 dup2(fd, STDOUT_FILENO);
1106         dup2(fd, STDERR_FILENO);
1107         if (fd > STDERR_FILENO)
1108                 close(fd);
1109
1110         /* set scheduling priority for the daemon */
1111         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1112
1113         chdir("/");
1114         umask(022);
1115
1116         /* become session leader */
1117         sid = setsid();
1118         dbg("our session is %d\n", sid);
1119
1120         /* OOM_DISABLE == -17 */
1121         fd = open("/proc/self/oom_adj", O_RDWR);
1122         if (fd < 0)
1123                 err("error disabling OOM: %s\n", strerror(errno));
1124         else {
1125                 write(fd, "-17", 3);
1126                 close(fd);
1127         }
1128
1129         fd = open("/dev/kmsg", O_WRONLY);
1130         if (fd > 0) {
1131                 const char *str = "<6>udevd version " VERSION " started\n";
1132
1133                 write(fd, str, strlen(str));
1134                 close(fd);
1135         }
1136
1137         /* set signal handlers */
1138         memset(&act, 0x00, sizeof(struct sigaction));
1139         act.sa_handler = (void (*)(int)) sig_handler;
1140         sigemptyset(&act.sa_mask);
1141         act.sa_flags = SA_RESTART;
1142         sigaction(SIGINT, &act, NULL);
1143         sigaction(SIGTERM, &act, NULL);
1144         sigaction(SIGCHLD, &act, NULL);
1145         sigaction(SIGHUP, &act, NULL);
1146
1147         /* watch rules directory */
1148         inotify_fd = inotify_init();
1149         if (inotify_fd >= 0) {
1150                 if (udev_rules_dir[0] != '\0') {
1151                         inotify_add_watch(inotify_fd, udev_rules_dir,
1152                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1153                 } else {
1154                         char filename[PATH_MAX];
1155
1156                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
1157                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1158                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
1159                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1160
1161                         /* watch dynamic rules directory */
1162                         strlcpy(filename, udev_root, sizeof(filename));
1163                         strlcat(filename, "/.udev/rules.d", sizeof(filename));
1164                         inotify_add_watch(inotify_fd, filename,
1165                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1166                 }
1167         } else if (errno == ENOSYS)
1168                 err("the kernel does not support inotify, udevd can't monitor rules file changes\n");
1169         else
1170                 err("inotify_init failed: %s\n", strerror(errno));
1171
1172         /* maximum limit of forked childs */
1173         value = getenv("UDEVD_MAX_CHILDS");
1174         if (value)
1175                 max_childs = strtoul(value, NULL, 10);
1176         else {
1177                 int memsize = mem_size_mb();
1178                 if (memsize > 0)
1179                         max_childs = 128 + (memsize / 4);
1180                 else
1181                         max_childs = UDEVD_MAX_CHILDS;
1182         }
1183         info("initialize max_childs to %u\n", max_childs);
1184
1185         /* start to throttle forking if maximum number of _running_ childs is reached */
1186         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1187         if (value)
1188                 max_childs_running = strtoull(value, NULL, 10);
1189         else {
1190                 int cpus = cpu_count();
1191                 if (cpus > 0)
1192                         max_childs_running = 8 + (8 * cpus);
1193                 else
1194                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1195         }
1196         info("initialize max_childs_running to %u\n", max_childs_running);
1197
1198         /* clear environment for forked event processes */
1199         clearenv();
1200
1201         /* export log_priority , as called programs may want to follow that setting */
1202         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1203         putenv(udev_log);
1204         if (debug_trace)
1205                 putenv("DEBUG=1");
1206
1207         maxfd = udevd_sock;
1208         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1209         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1210         maxfd = UDEV_MAX(maxfd, inotify_fd);
1211
1212         while (!udev_exit) {
1213                 struct udevd_uevent_msg *msg;
1214                 int fdcount;
1215
1216                 FD_ZERO(&readfds);
1217                 FD_SET(signal_pipe[READ_END], &readfds);
1218                 FD_SET(udevd_sock, &readfds);
1219                 FD_SET(uevent_netlink_sock, &readfds);
1220                 if (inotify_fd >= 0)
1221                         FD_SET(inotify_fd, &readfds);
1222
1223                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1224                 if (fdcount < 0) {
1225                         if (errno != EINTR)
1226                                 err("error in select: %s\n", strerror(errno));
1227                         continue;
1228                 }
1229
1230                 /* get control message */
1231                 if (FD_ISSET(udevd_sock, &readfds))
1232                         get_ctrl_msg();
1233
1234                 /* get netlink message */
1235                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1236                         msg = get_netlink_msg();
1237                         if (msg)
1238                                 msg_queue_insert(msg);
1239                 }
1240
1241                 /* received a signal, clear our notification pipe */
1242                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1243                         char buf[256];
1244
1245                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1246                 }
1247
1248                 /* rules directory inotify watch */
1249                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1250                         int nbytes;
1251
1252                         /* discard all possible events, we can just reload the config */
1253                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1254                                 char *buf;
1255
1256                                 reload_config = 1;
1257                                 buf = malloc(nbytes);
1258                                 if (buf == NULL) {
1259                                         err("error getting buffer for inotify, disable watching\n");
1260                                         close(inotify_fd);
1261                                         inotify_fd = -1;
1262                                 }
1263                                 read(inotify_fd, buf, nbytes);
1264                                 free(buf);
1265                         }
1266                 }
1267
1268                 /* rules changed, set by inotify or a HUP signal */
1269                 if (reload_config) {
1270                         reload_config = 0;
1271                         udev_rules_cleanup(&rules);
1272                         udev_rules_init(&rules, 1);
1273                 }
1274
1275                 /* forked child has returned */
1276                 if (sigchilds_waiting) {
1277                         sigchilds_waiting = 0;
1278                         reap_sigchilds();
1279                 }
1280
1281                 if (run_exec_q) {
1282                         run_exec_q = 0;
1283                         if (!stop_exec_q)
1284                                 msg_queue_manager();
1285                 }
1286         }
1287         rc = 0;
1288
1289 exit:
1290         udev_rules_cleanup(&rules);
1291         sysfs_cleanup();
1292         selinux_exit();
1293
1294         if (signal_pipe[READ_END] >= 0)
1295                 close(signal_pipe[READ_END]);
1296         if (signal_pipe[WRITE_END] >= 0)
1297                 close(signal_pipe[WRITE_END]);
1298
1299         if (udevd_sock >= 0)
1300                 close(udevd_sock);
1301         if (inotify_fd >= 0)
1302                 close(inotify_fd);
1303         if (uevent_netlink_sock >= 0)
1304                 close(uevent_netlink_sock);
1305
1306         logging_close();
1307
1308         return rc;
1309 }