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