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