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