udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   6  *
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stddef.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <time.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47 #include "udevd.h"
  48
  49 static struct udev_rules rules;
  50 static int udevd_sock = -1;
  51 static int uevent_netlink_sock = -1;
  52 static int inotify_fd = -1;
  53 static pid_t sid;
  54
  55 static int signal_pipe[2] = {-1, -1};
  56 static volatile int sigchilds_waiting;
  57 static volatile int udev_exit;
  58 static volatile int reload_config;
  59 static int run_exec_q;
  60 static int stop_exec_q;
  61 static int max_childs;
  62 static int max_childs_running;
  63 static char udev_log[32];
  64
  65 static LIST_HEAD(exec_list);
  66 static LIST_HEAD(running_list);
  67
  68
  69 #ifdef USE_LOG
  70 void log_message(int priority, const char *format, ...)
  71 {
  72         va_list args;
  73
  74         if (priority > udev_log_priority)
  75                 return;
  76
  77         va_start(args, format);
  78         vsyslog(priority, format, args);
  79         va_end(args);
  80 }
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct udevd_uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* reset to default */
 104         act.sa_handler = SIG_DFL;
 105         sigaction(SIGINT, &act, NULL);
 106         sigaction(SIGTERM, &act, NULL);
 107         sigaction(SIGCHLD, &act, NULL);
 108         sigaction(SIGHUP, &act, NULL);
 109
 110         /* trigger timeout to prevent hanging processes */
 111         alarm(UDEV_ALARM_TIMEOUT);
 112
 113         /* reconstruct event environment from message */
 114         for (i = 0; msg->envp[i]; i++)
 115                 putenv(msg->envp[i]);
 116
 117         udev = udev_device_init();
 118         if (udev == NULL)
 119                 return -1;
 120         strlcpy(udev->action, msg->action, sizeof(udev->action));
 121         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 122         udev->devt = msg->devt;
 123
 124         retval = udev_device_event(&rules, udev);
 125
 126         /* run programs collected by RUN-key*/
 127         if (retval == 0 && !udev->ignore_device && udev_run) {
 128                 struct name_entry *name_loop;
 129
 130                 dbg("executing run list");
 131                 list_for_each_entry(name_loop, &udev->run_list, node) {
 132                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 133                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 134                         else {
 135                                 char program[PATH_SIZE];
 136
 137                                 strlcpy(program, name_loop->name, sizeof(program));
 138                                 udev_rules_apply_format(udev, program, sizeof(program));
 139                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 140                                                 (udev_log_priority >= LOG_INFO)))
 141                                         retval = -1;
 142                         }
 143                 }
 144         }
 145
 146         udev_device_cleanup(udev);
 147         return retval;
 148 }
 149
 150 enum event_state {
 151         EVENT_QUEUED,
 152         EVENT_FINISHED,
 153         EVENT_FAILED,
 154 };
 155
 156 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 157 {
 158         char filename[PATH_SIZE];
 159         char filename_failed[PATH_SIZE];
 160         char target[PATH_SIZE];
 161         size_t start, end, i;
 162         struct udevd_uevent_msg *loop_msg;
 163
 164         /* add location of queue files */
 165         strlcpy(filename, udev_root, sizeof(filename));
 166         strlcat(filename, "/", sizeof(filename));
 167         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 168         end = strlcat(filename, msg->devpath, sizeof(filename));
 169         if (end > sizeof(filename))
 170                 end = sizeof(filename);
 171
 172         /* replace '/' to transform path into a filename */
 173         for (i = start+1; i < end; i++)
 174                 if (filename[i] == '/')
 175                         filename[i] = PATH_TO_NAME_CHAR;
 176
 177         /* add location of failed files */
 178         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 179         strlcat(filename_failed, "/", sizeof(filename_failed));
 180         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 181         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 182         if (end > sizeof(filename_failed))
 183                 end = sizeof(filename_failed);
 184
 185         /* replace '/' to transform path into a filename */
 186         for (i = start+1; i < end; i++)
 187                 if (filename_failed[i] == '/')
 188                         filename_failed[i] = PATH_TO_NAME_CHAR;
 189
 190         switch (state) {
 191         case EVENT_QUEUED:
 192                 unlink(filename_failed);
 193                 delete_path(filename_failed);
 194
 195                 strlcpy(target, sysfs_path, sizeof(target));
 196                 strlcat(target, msg->devpath, sizeof(target));
 197                 create_path(filename);
 198                 symlink(target, filename);
 199                 return;
 200         case EVENT_FINISHED:
 201         case EVENT_FAILED:
 202                 unlink(filename_failed);
 203                 delete_path(filename_failed);
 204
 205                 /* don't remove, if events for the same path are still pending */
 206                 list_for_each_entry(loop_msg, &running_list, node)
 207                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 208                                 return;
 209
 210                 list_for_each_entry(loop_msg, &exec_list, node)
 211                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 212                                 return;
 213
 214                 /* move failed events to the failed directory */
 215                 if (state == EVENT_FAILED) {
 216                         create_path(filename_failed);
 217                         rename(filename, filename_failed);
 218                 } else {
 219                         unlink(filename);
 220                 }
 221
 222                 /* clean up the queue directory */
 223                 delete_path(filename);
 224
 225                 return;
 226         }
 227 }
 228
 229 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 230 {
 231         list_del(&msg->node);
 232
 233         /* mark as failed, if add event returns non-zero */
 234         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 235                 export_event_state(msg, EVENT_FAILED);
 236         else
 237                 export_event_state(msg, EVENT_FINISHED);
 238
 239         free(msg);
 240 }
 241
 242 static void udev_event_run(struct udevd_uevent_msg *msg)
 243 {
 244         pid_t pid;
 245         int retval;
 246
 247         pid = fork();
 248         switch (pid) {
 249         case 0:
 250                 /* child */
 251                 close(uevent_netlink_sock);
 252                 close(udevd_sock);
 253                 if (inotify_fd >= 0)
 254                         close(inotify_fd);
 255                 close(signal_pipe[READ_END]);
 256                 close(signal_pipe[WRITE_END]);
 257                 logging_close();
 258
 259                 logging_init("udevd-event");
 260                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 261
 262                 retval = udev_event_process(msg);
 263                 info("seq %llu finished", msg->seqnum);
 264
 265                 logging_close();
 266                 if (retval)
 267                         exit(1);
 268                 exit(0);
 269         case -1:
 270                 err("fork of child failed: %s", strerror(errno));
 271                 msg_queue_delete(msg);
 272                 break;
 273         default:
 274                 /* get SIGCHLD in main loop */
 275                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 276                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 277                 msg->pid = pid;
 278         }
 279 }
 280
 281 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 282 {
 283         char filename[PATH_SIZE];
 284         int fd;
 285
 286         msg->queue_time = time(NULL);
 287
 288         strlcpy(filename, udev_root, sizeof(filename));
 289         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 290         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 291         if (fd >= 0) {
 292                 char str[32];
 293                 int len;
 294
 295                 len = sprintf(str, "%llu\n", msg->seqnum);
 296                 write(fd, str, len);
 297                 close(fd);
 298         }
 299
 300         export_event_state(msg, EVENT_QUEUED);
 301
 302         /* run all events with a timeout set immediately */
 303         if (msg->timeout != 0) {
 304                 list_add_tail(&msg->node, &running_list);
 305                 udev_event_run(msg);
 306                 return;
 307         }
 308
 309         list_add_tail(&msg->node, &exec_list);
 310         run_exec_q = 1;
 311 }
 312
 313 static int mem_size_mb(void)
 314 {
 315         int f;
 316         char buf[8192];
 317         long int len;
 318         const char *pos;
 319         long int memsize;
 320
 321         f = open("/proc/meminfo", O_RDONLY);
 322         if (f == -1)
 323                 return -1;
 324
 325         len = read(f, buf, sizeof(buf)-1);
 326         close(f);
 327
 328         if (len <= 0)
 329                 return -1;
 330         buf[len] = '\0';
 331
 332         pos = strstr(buf, "MemTotal: ");
 333         if (pos == NULL)
 334                 return -1;
 335
 336         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 337                 return -1;
 338
 339         return memsize / 1024;
 340 }
 341
 342 static int cpu_count(void)
 343 {
 344         int f;
 345         char buf[32768];
 346         int len;
 347         const char *pos;
 348         int count = 0;
 349
 350         f = open("/proc/stat", O_RDONLY);
 351         if (f == -1)
 352                 return -1;
 353
 354         len = read(f, buf, sizeof(buf)-1);
 355         close(f);
 356         if (len <= 0)
 357                 return -1;
 358         buf[len] = '\0';
 359
 360         pos = strstr(buf, "cpu");
 361         if (pos == NULL)
 362                 return -1;
 363
 364         while (pos != NULL) {
 365                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 366                         count++;
 367                 pos = strstr(&pos[3], "cpu");
 368         }
 369
 370         if (count == 0)
 371                 return -1;
 372         return count;
 373 }
 374
 375 static int running_processes(void)
 376 {
 377         int f;
 378         char buf[32768];
 379         int len;
 380         int running;
 381         const char *pos;
 382
 383         f = open("/proc/stat", O_RDONLY);
 384         if (f == -1)
 385                 return -1;
 386
 387         len = read(f, buf, sizeof(buf)-1);
 388         close(f);
 389         if (len <= 0)
 390                 return -1;
 391         buf[len] = '\0';
 392
 393         pos = strstr(buf, "procs_running ");
 394         if (pos == NULL)
 395                 return -1;
 396
 397         if (sscanf(pos, "procs_running %u", &running) != 1)
 398                 return -1;
 399
 400         return running;
 401 }
 402
 403 /* return the number of process es in our session, count only until limit */
 404 static int running_processes_in_session(pid_t session, int limit)
 405 {
 406         DIR *dir;
 407         struct dirent *dent;
 408         int running = 0;
 409
 410         dir = opendir("/proc");
 411         if (!dir)
 412                 return -1;
 413
 414         /* read process info from /proc */
 415         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 416                 int f;
 417                 char procdir[64];
 418                 char line[256];
 419                 const char *pos;
 420                 char state;
 421                 pid_t ppid, pgrp, sess;
 422                 int len;
 423
 424                 if (!isdigit(dent->d_name[0]))
 425                         continue;
 426
 427                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 428                 procdir[sizeof(procdir)-1] = '\0';
 429
 430                 f = open(procdir, O_RDONLY);
 431                 if (f == -1)
 432                         continue;
 433
 434                 len = read(f, line, sizeof(line)-1);
 435                 close(f);
 436
 437                 if (len <= 0)
 438                         continue;
 439                 else
 440                         line[len] = '\0';
 441
 442                 /* skip ugly program name */
 443                 pos = strrchr(line, ')') + 2;
 444                 if (pos == NULL)
 445                         continue;
 446
 447                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 448                         continue;
 449
 450                 /* count only processes in our session */
 451                 if (sess != session)
 452                         continue;
 453
 454                 /* count only running, no sleeping processes */
 455                 if (state != 'R')
 456                         continue;
 457
 458                 running++;
 459                 if (limit > 0 && running >= limit)
 460                         break;
 461         }
 462         closedir(dir);
 463
 464         return running;
 465 }
 466
 467 static int compare_devpath(const char *running, const char *waiting)
 468 {
 469         int i;
 470
 471         for (i = 0; i < PATH_SIZE; i++) {
 472                 /* identical device event found */
 473                 if (running[i] == '\0' && waiting[i] == '\0')
 474                         return 1;
 475
 476                 /* parent device event found */
 477                 if (running[i] == '\0' && waiting[i] == '/')
 478                         return 2;
 479
 480                 /* child device event found */
 481                 if (running[i] == '/' && waiting[i] == '\0')
 482                         return 3;
 483
 484                 /* no matching event */
 485                 if (running[i] != waiting[i])
 486                         break;
 487         }
 488
 489         return 0;
 490 }
 491
 492 /* returns still running task for the same device, its parent or its physical device */
 493 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 494 {
 495         struct udevd_uevent_msg *loop_msg;
 496         int childs_count = 0;
 497
 498         list_for_each_entry(loop_msg, &running_list, node) {
 499                 if (limit && childs_count++ > limit) {
 500                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 501                         return 1;
 502                 }
 503
 504                 /* return running parent/child device event */
 505                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 506                         dbg("%llu, child device event still running %llu (%s)",
 507                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 508                         return 2;
 509                 }
 510
 511                 /* return running physical device event */
 512                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 513                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 514                                 dbg("%llu, physical device event still running %llu (%s)",
 515                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 516                                 return 3;
 517                         }
 518         }
 519
 520         return 0;
 521 }
 522
 523 /* exec queue management routine executes the events and serializes events in the same sequence */
 524 static void msg_queue_manager(void)
 525 {
 526         struct udevd_uevent_msg *loop_msg;
 527         struct udevd_uevent_msg *tmp_msg;
 528         int running;
 529
 530         if (list_empty(&exec_list))
 531                 return;
 532
 533         running = running_processes();
 534         dbg("%d processes runnning on system", running);
 535         if (running < 0)
 536                 running = max_childs_running;
 537
 538         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 539                 /* check running processes in our session and possibly throttle */
 540                 if (running >= max_childs_running) {
 541                         running = running_processes_in_session(sid, max_childs_running+10);
 542                         dbg("at least %d processes running in session", running);
 543                         if (running >= max_childs_running) {
 544                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 545                                 return;
 546                         }
 547                 }
 548
 549                 /* don't run two processes for the same devpath and wait for the parent*/
 550                 if (running_with_devpath(loop_msg, max_childs)) {
 551                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 552                         continue;
 553                 }
 554
 555                 /* move event to run list */
 556                 list_move_tail(&loop_msg->node, &running_list);
 557                 udev_event_run(loop_msg);
 558                 running++;
 559                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 560         }
 561 }
 562
 563 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 564 {
 565         int bufpos;
 566         int i;
 567         struct udevd_uevent_msg *msg;
 568         int major = 0;
 569         int minor = 0;
 570
 571         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 572         if (msg == NULL)
 573                 return NULL;
 574         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 575
 576         /* copy environment buffer and reconstruct envp */
 577         memcpy(msg->envbuf, buf, buf_size);
 578         bufpos = 0;
 579         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 580                 int keylen;
 581                 char *key;
 582
 583                 key = &msg->envbuf[bufpos];
 584                 keylen = strlen(key);
 585                 msg->envp[i] = key;
 586                 bufpos += keylen + 1;
 587                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 588
 589                 /* remember some keys for further processing */
 590                 if (strncmp(key, "ACTION=", 7) == 0)
 591                         msg->action = &key[7];
 592                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 593                         msg->devpath = &key[8];
 594                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 595                         msg->subsystem = &key[10];
 596                 else if (strncmp(key, "DRIVER=", 7) == 0)
 597                         msg->driver = &key[7];
 598                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 599                         msg->seqnum = strtoull(&key[7], NULL, 10);
 600                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 601                         msg->physdevpath = &key[12];
 602                 else if (strncmp(key, "MAJOR=", 6) == 0)
 603                         major = strtoull(&key[6], NULL, 10);
 604                 else if (strncmp(key, "MINOR=", 6) == 0)
 605                         minor = strtoull(&key[6], NULL, 10);
 606                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 607                         msg->timeout = strtoull(&key[8], NULL, 10);
 608         }
 609         msg->devt = makedev(major, minor);
 610         msg->envp[i++] = "UDEVD_EVENT=1";
 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
 633         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 634         iov.iov_base = &ctrl_msg;
 635         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 636
 637         memset(&smsg, 0x00, sizeof(struct msghdr));
 638         smsg.msg_iov = &iov;
 639         smsg.msg_iovlen = 1;
 640         smsg.msg_control = cred_msg;
 641         smsg.msg_controllen = sizeof(cred_msg);
 642
 643         size = recvmsg(udevd_sock, &smsg, 0);
 644         if (size <  0) {
 645                 if (errno != EINTR)
 646                         err("unable to receive user udevd message: %s", strerror(errno));
 647                 return;
 648         }
 649         cmsg = CMSG_FIRSTHDR(&smsg);
 650         cred = (struct ucred *) CMSG_DATA(cmsg);
 651
 652         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 653                 err("no sender credentials received, message ignored");
 654                 return;
 655         }
 656
 657         if (cred->uid != 0) {
 658                 err("sender uid=%i, message ignored", cred->uid);
 659                 return;
 660         }
 661
 662         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 663                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 664                 return;
 665         }
 666
 667         switch (ctrl_msg.type) {
 668         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 669                 info("udevd message (STOP_EXEC_QUEUE) received");
 670                 stop_exec_q = 1;
 671                 break;
 672         case UDEVD_CTRL_START_EXEC_QUEUE:
 673                 info("udevd message (START_EXEC_QUEUE) received");
 674                 stop_exec_q = 0;
 675                 msg_queue_manager();
 676                 break;
 677         case UDEVD_CTRL_SET_LOG_LEVEL:
 678                 intval = (int *) ctrl_msg.buf;
 679                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 680                 udev_log_priority = *intval;
 681                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 682                 putenv(udev_log);
 683                 break;
 684         case UDEVD_CTRL_SET_MAX_CHILDS:
 685                 intval = (int *) ctrl_msg.buf;
 686                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 687                 max_childs = *intval;
 688                 break;
 689         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 690                 intval = (int *) ctrl_msg.buf;
 691                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 692                 max_childs_running = *intval;
 693                 break;
 694         case UDEVD_CTRL_RELOAD_RULES:
 695                 info("udevd message (RELOAD_RULES) received");
 696                 reload_config = 1;
 697                 break;
 698         default:
 699                 err("unknown control message type");
 700         }
 701 }
 702
 703 /* receive the kernel user event message and do some sanity checks */
 704 static struct udevd_uevent_msg *get_netlink_msg(void)
 705 {
 706         struct udevd_uevent_msg *msg;
 707         int bufpos;
 708         ssize_t size;
 709         static char buffer[UEVENT_BUFFER_SIZE+512];
 710         char *pos;
 711
 712         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 713         if (size <  0) {
 714                 if (errno != EINTR)
 715                         err("unable to receive kernel netlink message: %s", strerror(errno));
 716                 return NULL;
 717         }
 718
 719         if ((size_t)size > sizeof(buffer)-1)
 720                 size = sizeof(buffer)-1;
 721         buffer[size] = '\0';
 722         dbg("uevent_size=%zi", size);
 723
 724         /* start of event payload */
 725         bufpos = strlen(buffer)+1;
 726         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 727         if (msg == NULL)
 728                 return NULL;
 729
 730         /* validate message */
 731         pos = strchr(buffer, '@');
 732         if (pos == NULL) {
 733                 err("invalid uevent '%s'", buffer);
 734                 free(msg);
 735                 return NULL;
 736         }
 737         pos[0] = '\0';
 738
 739         if (msg->action == NULL) {
 740                 info("no ACTION in payload found, skip event '%s'", buffer);
 741                 free(msg);
 742                 return NULL;
 743         }
 744
 745         if (strcmp(msg->action, buffer) != 0) {
 746                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 747                 free(msg);
 748                 return NULL;
 749         }
 750
 751         return msg;
 752 }
 753
 754 static void asmlinkage sig_handler(int signum)
 755 {
 756         switch (signum) {
 757                 case SIGINT:
 758                 case SIGTERM:
 759                         udev_exit = 1;
 760                         break;
 761                 case SIGCHLD:
 762                         /* set flag, then write to pipe if needed */
 763                         sigchilds_waiting = 1;
 764                         break;
 765                 case SIGHUP:
 766                         reload_config = 1;
 767                         break;
 768         }
 769
 770         /* write to pipe, which will wakeup select() in our mainloop */
 771         write(signal_pipe[WRITE_END], "", 1);
 772 }
 773
 774 static void udev_done(int pid, int exitstatus)
 775 {
 776         /* find msg associated with pid and delete it */
 777         struct udevd_uevent_msg *msg;
 778
 779         list_for_each_entry(msg, &running_list, node) {
 780                 if (msg->pid == pid) {
 781                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 782                              exitstatus, time(NULL) - msg->queue_time);
 783                         msg->exitstatus = exitstatus;
 784                         msg_queue_delete(msg);
 785
 786                         /* there may be events waiting with the same devpath */
 787                         run_exec_q = 1;
 788                         return;
 789                 }
 790         }
 791 }
 792
 793 static void reap_sigchilds(void)
 794 {
 795         pid_t pid;
 796         int status;
 797
 798         while (1) {
 799                 pid = waitpid(-1, &status, WNOHANG);
 800                 if (pid <= 0)
 801                         break;
 802                 if (WIFEXITED(status))
 803                         status = WEXITSTATUS(status);
 804                 else if (WIFSIGNALED(status))
 805                         status = WTERMSIG(status) + 128;
 806                 else
 807                         status = 0;
 808                 udev_done(pid, status);
 809         }
 810 }
 811
 812 static int init_udevd_socket(void)
 813 {
 814         struct sockaddr_un saddr;
 815         socklen_t addrlen;
 816         const int feature_on = 1;
 817         int retval;
 818
 819         memset(&saddr, 0x00, sizeof(saddr));
 820         saddr.sun_family = AF_LOCAL;
 821         /* use abstract namespace for socket path */
 822         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 823         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 824
 825         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 826         if (udevd_sock == -1) {
 827                 err("error getting socket: %s", strerror(errno));
 828                 return -1;
 829         }
 830
 831         /* the bind takes care of ensuring only one copy running */
 832         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 833         if (retval < 0) {
 834                 err("bind failed: %s", strerror(errno));
 835                 close(udevd_sock);
 836                 udevd_sock = -1;
 837                 return -1;
 838         }
 839
 840         /* enable receiving of the sender credentials */
 841         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 842
 843         return 0;
 844 }
 845
 846 static int init_uevent_netlink_sock(void)
 847 {
 848         struct sockaddr_nl snl;
 849         const int buffersize = 16 * 1024 * 1024;
 850         int retval;
 851
 852         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 853         snl.nl_family = AF_NETLINK;
 854         snl.nl_pid = getpid();
 855         snl.nl_groups = 1;
 856
 857         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 858         if (uevent_netlink_sock == -1) {
 859                 err("error getting socket: %s", strerror(errno));
 860                 return -1;
 861         }
 862
 863         /* set receive buffersize */
 864         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 865
 866         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 867         if (retval < 0) {
 868                 err("bind failed: %s", strerror(errno));
 869                 close(uevent_netlink_sock);
 870                 uevent_netlink_sock = -1;
 871                 return -1;
 872         }
 873         return 0;
 874 }
 875
 876 static void export_initial_seqnum(void)
 877 {
 878         char filename[PATH_SIZE];
 879         int fd;
 880         char seqnum[32];
 881         ssize_t len = 0;
 882
 883         strlcpy(filename, sysfs_path, sizeof(filename));
 884         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 885         fd = open(filename, O_RDONLY);
 886         if (fd >= 0) {
 887                 len = read(fd, seqnum, sizeof(seqnum)-1);
 888                 close(fd);
 889         }
 890         if (len <= 0) {
 891                 strcpy(seqnum, "0\n");
 892                 len = 3;
 893         }
 894         strlcpy(filename, udev_root, sizeof(filename));
 895         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 896         create_path(filename);
 897         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 898         if (fd >= 0) {
 899                 write(fd, seqnum, len);
 900                 close(fd);
 901         }
 902 }
 903
 904 int main(int argc, char *argv[], char *envp[])
 905 {
 906         int retval;
 907         int fd;
 908         struct sigaction act;
 909         fd_set readfds;
 910         const char *value;
 911         int daemonize = 0;
 912         int i;
 913         int rc = 0;
 914         int maxfd;
 915
 916         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 917         fd = open("/dev/null", O_RDWR);
 918         if (fd >= 0) {
 919                 if (fd != STDIN_FILENO)
 920                         dup2(fd, STDIN_FILENO);
 921                 if (fd != STDOUT_FILENO)
 922                         dup2(fd, STDOUT_FILENO);
 923                 if (fd != STDERR_FILENO)
 924                         dup2(fd, STDERR_FILENO);
 925                 if (fd > STDERR_FILENO)
 926                         close(fd);
 927         }
 928
 929         logging_init("udevd");
 930         if (fd < 0)
 931                 err("fatal, could not open /dev/null: %s", strerror(errno));
 932
 933         udev_config_init();
 934         dbg("version %s", UDEV_VERSION);
 935
 936         if (getuid() != 0) {
 937                 err("need to be root, exit");
 938                 goto exit;
 939         }
 940
 941         /* parse commandline options */
 942         for (i = 1 ; i < argc; i++) {
 943                 char *arg = argv[i];
 944                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 945                         info("will daemonize");
 946                         daemonize = 1;
 947                 }
 948         }
 949
 950         /* init sockets to receive events */
 951         if (init_udevd_socket() < 0) {
 952                 if (errno == EADDRINUSE) {
 953                         err("another udevd running, exit");
 954                         rc = 1;
 955                 } else {
 956                         err("error initializing udevd socket: %s", strerror(errno));
 957                         rc = 2;
 958                 }
 959                 goto exit;
 960         }
 961
 962         if (init_uevent_netlink_sock() < 0) {
 963                 err("uevent socket not available");
 964                 rc = 3;
 965                 goto exit;
 966         }
 967
 968         /* parse the rules and keep it in memory */
 969         sysfs_init();
 970         udev_rules_init(&rules, 1);
 971
 972         export_initial_seqnum();
 973
 974         if (daemonize) {
 975                 pid_t pid;
 976
 977                 pid = fork();
 978                 switch (pid) {
 979                 case 0:
 980                         dbg("daemonized fork running");
 981                         break;
 982                 case -1:
 983                         err("fork of daemon failed: %s", strerror(errno));
 984                         rc = 4;
 985                         goto exit;
 986                 default:
 987                         dbg("child [%u] running, parent exits", pid);
 988                         goto exit;
 989                 }
 990         }
 991
 992         /* set scheduling priority for the daemon */
 993         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 994
 995         chdir("/");
 996         umask(022);
 997
 998         /* become session leader */
 999         sid = setsid();
1000         dbg("our session is %d", sid);
1001
1002         /* OOM_DISABLE == -17 */
1003         fd = open("/proc/self/oom_adj", O_RDWR);
1004         if (fd < 0)
1005                 err("error disabling OOM: %s", strerror(errno));
1006         else {
1007                 write(fd, "-17", 3);
1008                 close(fd);
1009         }
1010
1011         /* setup signal handler pipe */
1012         retval = pipe(signal_pipe);
1013         if (retval < 0) {
1014                 err("error getting pipes: %s", strerror(errno));
1015                 goto exit;
1016         }
1017
1018         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1019         if (retval < 0) {
1020                 err("error fcntl on read pipe: %s", strerror(errno));
1021                 goto exit;
1022         }
1023         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1024         if (retval < 0) {
1025                 err("error fcntl on read pipe: %s", strerror(errno));
1026                 goto exit;
1027         }
1028
1029         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1030         if (retval < 0) {
1031                 err("error fcntl on write pipe: %s", strerror(errno));
1032                 goto exit;
1033         }
1034         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1035         if (retval < 0) {
1036                 err("error fcntl on write pipe: %s", strerror(errno));
1037                 goto exit;
1038         }
1039
1040         /* set signal handlers */
1041         memset(&act, 0x00, sizeof(struct sigaction));
1042         act.sa_handler = (void (*)(int)) sig_handler;
1043         sigemptyset(&act.sa_mask);
1044         act.sa_flags = SA_RESTART;
1045         sigaction(SIGINT, &act, NULL);
1046         sigaction(SIGTERM, &act, NULL);
1047         sigaction(SIGCHLD, &act, NULL);
1048         sigaction(SIGHUP, &act, NULL);
1049
1050         /* watch rules directory */
1051         inotify_fd = inotify_init();
1052         if (inotify_fd >= 0)
1053                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1054         else if (errno == ENOSYS)
1055                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1056         else
1057                 err("inotify_init failed: %s", strerror(errno));
1058
1059         /* maximum limit of forked childs */
1060         value = getenv("UDEVD_MAX_CHILDS");
1061         if (value)
1062                 max_childs = strtoul(value, NULL, 10);
1063         else {
1064                 int memsize = mem_size_mb();
1065                 if (memsize > 0)
1066                         max_childs = 128 + (memsize / 4);
1067                 else
1068                         max_childs = UDEVD_MAX_CHILDS;
1069         }
1070         info("initialize max_childs to %u", max_childs);
1071
1072         /* start to throttle forking if maximum number of _running_ childs is reached */
1073         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1074         if (value)
1075                 max_childs_running = strtoull(value, NULL, 10);
1076         else {
1077                 int cpus = cpu_count();
1078                 if (cpus > 0)
1079                         max_childs_running = 8 + (8 * cpus);
1080                 else
1081                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1082         }
1083         info("initialize max_childs_running to %u", max_childs_running);
1084
1085         /* clear environment for forked event processes */
1086         clearenv();
1087
1088         /* export log_priority , as called programs may want to follow that setting */
1089         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1090         putenv(udev_log);
1091
1092         maxfd = udevd_sock;
1093         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1094         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1095         maxfd = UDEV_MAX(maxfd, inotify_fd);
1096
1097         while (!udev_exit) {
1098                 struct udevd_uevent_msg *msg;
1099                 int fdcount;
1100
1101                 FD_ZERO(&readfds);
1102                 FD_SET(signal_pipe[READ_END], &readfds);
1103                 FD_SET(udevd_sock, &readfds);
1104                 FD_SET(uevent_netlink_sock, &readfds);
1105                 if (inotify_fd >= 0)
1106                         FD_SET(inotify_fd, &readfds);
1107
1108                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1109                 if (fdcount < 0) {
1110                         if (errno != EINTR)
1111                                 err("error in select: %s", strerror(errno));
1112                         continue;
1113                 }
1114
1115                 /* get control message */
1116                 if (FD_ISSET(udevd_sock, &readfds))
1117                         get_ctrl_msg();
1118
1119                 /* get netlink message */
1120                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1121                         msg = get_netlink_msg();
1122                         if (msg)
1123                                 msg_queue_insert(msg);
1124                 }
1125
1126                 /* received a signal, clear our notification pipe */
1127                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1128                         char buf[256];
1129
1130                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1131                 }
1132
1133                 /* rules directory inotify watch */
1134                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1135                         int nbytes;
1136
1137                         /* discard all possible events, we can just reload the config */
1138                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1139                                 char *buf;
1140
1141                                 reload_config = 1;
1142                                 buf = malloc(nbytes);
1143                                 if (!buf) {
1144                                         err("error getting buffer for inotify, disable watching");
1145                                         close(inotify_fd);
1146                                         inotify_fd = -1;
1147                                 }
1148                                 read(inotify_fd, buf, nbytes);
1149                                 free(buf);
1150                         }
1151                 }
1152
1153                 /* rules changed, set by inotify or a signal*/
1154                 if (reload_config) {
1155                         reload_config = 0;
1156                         udev_rules_cleanup(&rules);
1157                         udev_rules_init(&rules, 1);
1158                 }
1159
1160                 /* forked child has returned */
1161                 if (sigchilds_waiting) {
1162                         sigchilds_waiting = 0;
1163                         reap_sigchilds();
1164                 }
1165
1166                 if (run_exec_q) {
1167                         run_exec_q = 0;
1168                         if (!stop_exec_q)
1169                                 msg_queue_manager();
1170                 }
1171         }
1172
1173 exit:
1174         udev_rules_cleanup(&rules);
1175         sysfs_cleanup();
1176
1177         if (signal_pipe[READ_END] >= 0)
1178                 close(signal_pipe[READ_END]);
1179         if (signal_pipe[WRITE_END] >= 0)
1180                 close(signal_pipe[WRITE_END]);
1181
1182         if (udevd_sock >= 0)
1183                 close(udevd_sock);
1184         if (inotify_fd >= 0)
1185                 close(inotify_fd);
1186         if (uevent_netlink_sock >= 0)
1187                 close(uevent_netlink_sock);
1188
1189         logging_close();
1190
1191         return rc;
1192 }