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