udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static int debug_trace;
  49 static int verbose;
  50
  51 static struct udev_rules rules;
  52 static int udevd_sock = -1;
  53 static int uevent_netlink_sock = -1;
  54 static int inotify_fd = -1;
  55 static pid_t sid;
  56
  57 static int signal_pipe[2] = {-1, -1};
  58 static volatile int sigchilds_waiting;
  59 static volatile int udev_exit;
  60 static volatile int reload_config;
  61 static int run_exec_q;
  62 static int stop_exec_q;
  63 static int max_childs;
  64 static int max_childs_running;
  65 static char udev_log[32];
  66
  67 static LIST_HEAD(exec_list);
  68 static LIST_HEAD(running_list);
  69
  70
  71 #ifdef USE_LOG
  72 void log_message(int priority, const char *format, ...)
  73 {
  74         va_list args;
  75
  76         if (priority > udev_log_priority)
  77                 return;
  78
  79         va_start(args, format);
  80         vsyslog(priority, format, args);
  81         va_end(args);
  82
  83         if (verbose) {
  84                 va_start(args, format);
  85                 vprintf(format, args);
  86                 va_end(args);
  87                 printf("\n");
  88         }
  89 }
  90
  91 #endif
  92
  93 static void asmlinkage udev_event_sig_handler(int signum)
  94 {
  95         if (signum == SIGALRM)
  96                 exit(1);
  97 }
  98
  99 static int udev_event_process(struct udevd_uevent_msg *msg)
 100 {
 101         struct sigaction act;
 102         struct udevice *udev;
 103         int i;
 104         int retval;
 105
 106         /* set signal handlers */
 107         memset(&act, 0x00, sizeof(act));
 108         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 109         sigemptyset (&act.sa_mask);
 110         act.sa_flags = 0;
 111         sigaction(SIGALRM, &act, NULL);
 112
 113         /* reset to default */
 114         act.sa_handler = SIG_DFL;
 115         sigaction(SIGINT, &act, NULL);
 116         sigaction(SIGTERM, &act, NULL);
 117         sigaction(SIGCHLD, &act, NULL);
 118         sigaction(SIGHUP, &act, NULL);
 119
 120         /* trigger timeout to prevent hanging processes */
 121         alarm(UDEV_ALARM_TIMEOUT);
 122
 123         /* reconstruct event environment from message */
 124         for (i = 0; msg->envp[i]; i++)
 125                 putenv(msg->envp[i]);
 126
 127         udev = udev_device_init(NULL);
 128         if (udev == NULL)
 129                 return -1;
 130         strlcpy(udev->action, msg->action, sizeof(udev->action));
 131         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 132         udev->devt = msg->devt;
 133
 134         retval = udev_device_event(&rules, udev);
 135
 136         /* run programs collected by RUN-key*/
 137         if (retval == 0 && !udev->ignore_device && udev_run) {
 138                 struct name_entry *name_loop;
 139
 140                 dbg("executing run list");
 141                 list_for_each_entry(name_loop, &udev->run_list, node) {
 142                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 143                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 144                         else {
 145                                 char program[PATH_SIZE];
 146
 147                                 strlcpy(program, name_loop->name, sizeof(program));
 148                                 udev_rules_apply_format(udev, program, sizeof(program));
 149                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 150                                                 (udev_log_priority >= LOG_INFO)))
 151                                         retval = -1;
 152                         }
 153                 }
 154         }
 155
 156         udev_device_cleanup(udev);
 157         return retval;
 158 }
 159
 160 enum event_state {
 161         EVENT_QUEUED,
 162         EVENT_FINISHED,
 163         EVENT_FAILED,
 164 };
 165
 166 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 167 {
 168         char filename[PATH_SIZE];
 169         char filename_failed[PATH_SIZE];
 170         size_t start;
 171         struct udevd_uevent_msg *loop_msg;
 172         int fd;
 173
 174         /* add location of queue files */
 175         strlcpy(filename, udev_root, sizeof(filename));
 176         strlcat(filename, "/", sizeof(filename));
 177         start = strlcat(filename, EVENT_QUEUE_DIR"/", sizeof(filename));
 178         strlcat(filename, msg->devpath, sizeof(filename));
 179         path_encode(&filename[start], sizeof(filename) - start);
 180
 181         /* add location of failed files */
 182         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 183         strlcat(filename_failed, "/", sizeof(filename_failed));
 184         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 185         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 186         path_encode(&filename_failed[start], sizeof(filename) - start);
 187
 188         switch (state) {
 189         case EVENT_QUEUED:
 190                 unlink(filename_failed);
 191                 delete_path(filename_failed);
 192                 create_path(filename);
 193                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 194                 if (fd > 0)
 195                         close(fd);
 196                 return;
 197         case EVENT_FINISHED:
 198         case EVENT_FAILED:
 199                 unlink(filename_failed);
 200                 delete_path(filename_failed);
 201
 202                 /* don't remove, if events for the same path are still pending */
 203                 list_for_each_entry(loop_msg, &running_list, node)
 204                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 205                                 return;
 206
 207                 list_for_each_entry(loop_msg, &exec_list, node)
 208                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 209                                 return;
 210
 211                 /* move failed events to the failed directory */
 212                 if (state == EVENT_FAILED) {
 213                         create_path(filename_failed);
 214                         rename(filename, filename_failed);
 215                 } else {
 216                         unlink(filename);
 217                 }
 218
 219                 /* clean up the queue directory */
 220                 delete_path(filename);
 221
 222                 return;
 223         }
 224 }
 225
 226 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 227 {
 228         list_del(&msg->node);
 229
 230         /* mark as failed, if add event returns non-zero */
 231         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 232                 export_event_state(msg, EVENT_FAILED);
 233         else
 234                 export_event_state(msg, EVENT_FINISHED);
 235
 236         free(msg);
 237 }
 238
 239 static void udev_event_run(struct udevd_uevent_msg *msg)
 240 {
 241         pid_t pid;
 242         int retval;
 243
 244         pid = fork();
 245         switch (pid) {
 246         case 0:
 247                 /* child */
 248                 close(uevent_netlink_sock);
 249                 close(udevd_sock);
 250                 if (inotify_fd >= 0)
 251                         close(inotify_fd);
 252                 close(signal_pipe[READ_END]);
 253                 close(signal_pipe[WRITE_END]);
 254                 logging_close();
 255
 256                 logging_init("udevd-event");
 257                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 258
 259                 retval = udev_event_process(msg);
 260                 info("seq %llu finished", msg->seqnum);
 261
 262                 logging_close();
 263                 if (retval)
 264                         exit(1);
 265                 exit(0);
 266         case -1:
 267                 err("fork of child failed: %s", strerror(errno));
 268                 msg_queue_delete(msg);
 269                 break;
 270         default:
 271                 /* get SIGCHLD in main loop */
 272                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 273                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 274                 msg->pid = pid;
 275         }
 276 }
 277
 278 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 279 {
 280         char filename[PATH_SIZE];
 281         int fd;
 282
 283         msg->queue_time = time(NULL);
 284
 285         strlcpy(filename, udev_root, sizeof(filename));
 286         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 287         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 288         if (fd >= 0) {
 289                 char str[32];
 290                 int len;
 291
 292                 len = sprintf(str, "%llu\n", msg->seqnum);
 293                 write(fd, str, len);
 294                 close(fd);
 295         }
 296
 297         export_event_state(msg, EVENT_QUEUED);
 298
 299         /* run one event after the other in debug mode */
 300         if (debug_trace) {
 301                 list_add_tail(&msg->node, &running_list);
 302                 udev_event_run(msg);
 303                 waitpid(msg->pid, NULL, 0);
 304                 msg_queue_delete(msg);
 305                 return;
 306         }
 307
 308         /* run all events with a timeout set immediately */
 309         if (msg->timeout != 0) {
 310                 list_add_tail(&msg->node, &running_list);
 311                 udev_event_run(msg);
 312                 return;
 313         }
 314
 315         list_add_tail(&msg->node, &exec_list);
 316         run_exec_q = 1;
 317 }
 318
 319 static int mem_size_mb(void)
 320 {
 321         FILE* f;
 322         char buf[4096];
 323         long int memsize = -1;
 324
 325         f = fopen("/proc/meminfo", "r");
 326         if (f == NULL)
 327                 return -1;
 328
 329         while (fgets(buf, sizeof(buf), f) != NULL) {
 330                 long int value;
 331
 332                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 333                         memsize = value / 1024;
 334                         break;
 335                 }
 336         }
 337
 338         fclose(f);
 339         return memsize;
 340 }
 341
 342 static int cpu_count(void)
 343 {
 344         FILE* f;
 345         char buf[4096];
 346         int count = 0;
 347
 348         f = fopen("/proc/stat", "r");
 349         if (f == NULL)
 350                 return -1;
 351
 352         while (fgets(buf, sizeof(buf), f) != NULL) {
 353                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 354                         count++;
 355         }
 356
 357         fclose(f);
 358         if (count == 0)
 359                 return -1;
 360         return count;
 361 }
 362
 363 static int running_processes(void)
 364 {
 365         FILE* f;
 366         char buf[4096];
 367         int running = -1;
 368
 369         f = fopen("/proc/stat", "r");
 370         if (f == NULL)
 371                 return -1;
 372
 373         while (fgets(buf, sizeof(buf), f) != NULL) {
 374                 int value;
 375
 376                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 377                         running = value;
 378                         break;
 379                 }
 380         }
 381
 382         fclose(f);
 383         return running;
 384 }
 385
 386 /* return the number of process es in our session, count only until limit */
 387 static int running_processes_in_session(pid_t session, int limit)
 388 {
 389         DIR *dir;
 390         struct dirent *dent;
 391         int running = 0;
 392
 393         dir = opendir("/proc");
 394         if (!dir)
 395                 return -1;
 396
 397         /* read process info from /proc */
 398         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 399                 int f;
 400                 char procdir[64];
 401                 char line[256];
 402                 const char *pos;
 403                 char state;
 404                 pid_t ppid, pgrp, sess;
 405                 int len;
 406
 407                 if (!isdigit(dent->d_name[0]))
 408                         continue;
 409
 410                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 411                 procdir[sizeof(procdir)-1] = '\0';
 412
 413                 f = open(procdir, O_RDONLY);
 414                 if (f == -1)
 415                         continue;
 416
 417                 len = read(f, line, sizeof(line)-1);
 418                 close(f);
 419
 420                 if (len <= 0)
 421                         continue;
 422                 else
 423                         line[len] = '\0';
 424
 425                 /* skip ugly program name */
 426                 pos = strrchr(line, ')') + 2;
 427                 if (pos == NULL)
 428                         continue;
 429
 430                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 431                         continue;
 432
 433                 /* count only processes in our session */
 434                 if (sess != session)
 435                         continue;
 436
 437                 /* count only running, no sleeping processes */
 438                 if (state != 'R')
 439                         continue;
 440
 441                 running++;
 442                 if (limit > 0 && running >= limit)
 443                         break;
 444         }
 445         closedir(dir);
 446
 447         return running;
 448 }
 449
 450 static int compare_devpath(const char *running, const char *waiting)
 451 {
 452         int i;
 453
 454         for (i = 0; i < PATH_SIZE; i++) {
 455                 /* identical device event found */
 456                 if (running[i] == '\0' && waiting[i] == '\0')
 457                         return 1;
 458
 459                 /* parent device event found */
 460                 if (running[i] == '\0' && waiting[i] == '/')
 461                         return 2;
 462
 463                 /* child device event found */
 464                 if (running[i] == '/' && waiting[i] == '\0')
 465                         return 3;
 466
 467                 /* no matching event */
 468                 if (running[i] != waiting[i])
 469                         break;
 470         }
 471
 472         return 0;
 473 }
 474
 475 /* lookup event for identical, parent, child, or physical device */
 476 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 477 {
 478         struct udevd_uevent_msg *loop_msg;
 479         int childs_count = 0;
 480
 481         /* check exec-queue which may still contain delayed events we depend on */
 482         list_for_each_entry(loop_msg, &exec_list, node) {
 483                 /* skip ourself and all later events */
 484                 if (loop_msg->seqnum >= msg->seqnum)
 485                         break;
 486
 487                 /* check identical, parent, or child device event */
 488                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 489                         dbg("%llu, device event still pending %llu (%s)",
 490                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 491                         return 2;
 492                 }
 493
 494                 /* check physical device event (special case of parent) */
 495                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 496                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 497                                 dbg("%llu, physical device event still pending %llu (%s)",
 498                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 499                                 return 3;
 500                         }
 501         }
 502
 503         /* check runing-queue for still running events */
 504         list_for_each_entry(loop_msg, &running_list, node) {
 505                 if (limit && childs_count++ > limit) {
 506                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 507                         return 1;
 508                 }
 509
 510                 /* check identical, parent, or child device event */
 511                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 512                         dbg("%llu, device event still running %llu (%s)",
 513                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 514                         return 2;
 515                 }
 516
 517                 /* check physical device event (special case of parent) */
 518                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 519                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 520                                 dbg("%llu, physical device event still running %llu (%s)",
 521                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 522                                 return 3;
 523                         }
 524         }
 525         return 0;
 526 }
 527
 528 /* serializes events for the identical and parent and child devices */
 529 static void msg_queue_manager(void)
 530 {
 531         struct udevd_uevent_msg *loop_msg;
 532         struct udevd_uevent_msg *tmp_msg;
 533         int running;
 534
 535         if (list_empty(&exec_list))
 536                 return;
 537
 538         running = running_processes();
 539         dbg("%d processes runnning on system", running);
 540         if (running < 0)
 541                 running = max_childs_running;
 542
 543         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 544                 /* check running processes in our session and possibly throttle */
 545                 if (running >= max_childs_running) {
 546                         running = running_processes_in_session(sid, max_childs_running+10);
 547                         dbg("at least %d processes running in session", running);
 548                         if (running >= max_childs_running) {
 549                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 550                                 return;
 551                         }
 552                 }
 553
 554                 /* serialize and wait for parent or child events */
 555                 if (devpath_busy(loop_msg, max_childs) != 0) {
 556                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 557                         continue;
 558                 }
 559
 560                 /* move event to run list */
 561                 list_move_tail(&loop_msg->node, &running_list);
 562                 udev_event_run(loop_msg);
 563                 running++;
 564                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 565         }
 566 }
 567
 568 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 569 {
 570         int bufpos;
 571         int i;
 572         struct udevd_uevent_msg *msg;
 573         char *physdevdriver_key = NULL;
 574         int maj = 0;
 575         int min = 0;
 576
 577         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 578         if (msg == NULL)
 579                 return NULL;
 580         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 581
 582         /* copy environment buffer and reconstruct envp */
 583         memcpy(msg->envbuf, buf, buf_size);
 584         bufpos = 0;
 585         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 586                 int keylen;
 587                 char *key;
 588
 589                 key = &msg->envbuf[bufpos];
 590                 keylen = strlen(key);
 591                 msg->envp[i] = key;
 592                 bufpos += keylen + 1;
 593                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 594
 595                 /* remember some keys for further processing */
 596                 if (strncmp(key, "ACTION=", 7) == 0)
 597                         msg->action = &key[7];
 598                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 599                         msg->devpath = &key[8];
 600                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 601                         msg->subsystem = &key[10];
 602                 else if (strncmp(key, "DRIVER=", 7) == 0)
 603                         msg->driver = &key[7];
 604                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 605                         msg->seqnum = strtoull(&key[7], NULL, 10);
 606                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 607                         msg->physdevpath = &key[12];
 608                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 609                         physdevdriver_key = key;
 610                 else if (strncmp(key, "MAJOR=", 6) == 0)
 611                         maj = strtoull(&key[6], NULL, 10);
 612                 else if (strncmp(key, "MINOR=", 6) == 0)
 613                         min = strtoull(&key[6], NULL, 10);
 614                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 615                         msg->timeout = strtoull(&key[8], NULL, 10);
 616         }
 617         msg->devt = makedev(maj, min);
 618         msg->envp[i++] = "UDEVD_EVENT=1";
 619
 620         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 621                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 622                 msg->envp[i++] = &physdevdriver_key[7];
 623                 msg->driver = &physdevdriver_key[14];
 624         }
 625
 626         msg->envp[i] = NULL;
 627
 628         if (msg->devpath == NULL || msg->action == NULL) {
 629                 info("DEVPATH or ACTION missing, ignore message");
 630                 free(msg);
 631                 return NULL;
 632         }
 633         return msg;
 634 }
 635
 636 /* receive the udevd message from userspace */
 637 static void get_ctrl_msg(void)
 638 {
 639         struct udevd_ctrl_msg ctrl_msg;
 640         ssize_t size;
 641         struct msghdr smsg;
 642         struct cmsghdr *cmsg;
 643         struct iovec iov;
 644         struct ucred *cred;
 645         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 646         int *intval;
 647         char *pos;
 648
 649         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 650         iov.iov_base = &ctrl_msg;
 651         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 652
 653         memset(&smsg, 0x00, sizeof(struct msghdr));
 654         smsg.msg_iov = &iov;
 655         smsg.msg_iovlen = 1;
 656         smsg.msg_control = cred_msg;
 657         smsg.msg_controllen = sizeof(cred_msg);
 658
 659         size = recvmsg(udevd_sock, &smsg, 0);
 660         if (size <  0) {
 661                 if (errno != EINTR)
 662                         err("unable to receive user udevd message: %s", strerror(errno));
 663                 return;
 664         }
 665         cmsg = CMSG_FIRSTHDR(&smsg);
 666         cred = (struct ucred *) CMSG_DATA(cmsg);
 667
 668         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 669                 err("no sender credentials received, message ignored");
 670                 return;
 671         }
 672
 673         if (cred->uid != 0) {
 674                 err("sender uid=%i, message ignored", cred->uid);
 675                 return;
 676         }
 677
 678         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 679                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 680                 return;
 681         }
 682
 683         switch (ctrl_msg.type) {
 684         case UDEVD_CTRL_ENV:
 685                 pos = strchr(ctrl_msg.buf, '=');
 686                 if (pos == NULL) {
 687                         err("wrong key format '%s'", ctrl_msg.buf);
 688                         break;
 689                 }
 690                 pos[0] = '\0';
 691                 if (pos[1] == '\0') {
 692                         info("udevd message (ENV) received, unset '%s'", ctrl_msg.buf);
 693                         unsetenv(ctrl_msg.buf);
 694                 } else {
 695                         info("udevd message (ENV) received, set '%s=%s'", ctrl_msg.buf, &pos[1]);
 696                         setenv(ctrl_msg.buf, &pos[1], 1);
 697                 }
 698                 break;
 699         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 700                 info("udevd message (STOP_EXEC_QUEUE) received");
 701                 stop_exec_q = 1;
 702                 break;
 703         case UDEVD_CTRL_START_EXEC_QUEUE:
 704                 info("udevd message (START_EXEC_QUEUE) received");
 705                 stop_exec_q = 0;
 706                 msg_queue_manager();
 707                 break;
 708         case UDEVD_CTRL_SET_LOG_LEVEL:
 709                 intval = (int *) ctrl_msg.buf;
 710                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 711                 udev_log_priority = *intval;
 712                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 713                 putenv(udev_log);
 714                 break;
 715         case UDEVD_CTRL_SET_MAX_CHILDS:
 716                 intval = (int *) ctrl_msg.buf;
 717                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 718                 max_childs = *intval;
 719                 break;
 720         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 721                 intval = (int *) ctrl_msg.buf;
 722                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 723                 max_childs_running = *intval;
 724                 break;
 725         case UDEVD_CTRL_RELOAD_RULES:
 726                 info("udevd message (RELOAD_RULES) received");
 727                 reload_config = 1;
 728                 break;
 729         default:
 730                 err("unknown control message type");
 731         }
 732 }
 733
 734 /* receive the kernel user event message and do some sanity checks */
 735 static struct udevd_uevent_msg *get_netlink_msg(void)
 736 {
 737         struct udevd_uevent_msg *msg;
 738         int bufpos;
 739         ssize_t size;
 740         static char buffer[UEVENT_BUFFER_SIZE+512];
 741         char *pos;
 742
 743         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 744         if (size <  0) {
 745                 if (errno != EINTR)
 746                         err("unable to receive kernel netlink message: %s", strerror(errno));
 747                 return NULL;
 748         }
 749
 750         if ((size_t)size > sizeof(buffer)-1)
 751                 size = sizeof(buffer)-1;
 752         buffer[size] = '\0';
 753         dbg("uevent_size=%zi", size);
 754
 755         /* start of event payload */
 756         bufpos = strlen(buffer)+1;
 757         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 758         if (msg == NULL)
 759                 return NULL;
 760
 761         /* validate message */
 762         pos = strchr(buffer, '@');
 763         if (pos == NULL) {
 764                 err("invalid uevent '%s'", buffer);
 765                 free(msg);
 766                 return NULL;
 767         }
 768         pos[0] = '\0';
 769
 770         if (msg->action == NULL) {
 771                 info("no ACTION in payload found, skip event '%s'", buffer);
 772                 free(msg);
 773                 return NULL;
 774         }
 775
 776         if (strcmp(msg->action, buffer) != 0) {
 777                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 778                 free(msg);
 779                 return NULL;
 780         }
 781
 782         return msg;
 783 }
 784
 785 static void asmlinkage sig_handler(int signum)
 786 {
 787         switch (signum) {
 788                 case SIGINT:
 789                 case SIGTERM:
 790                         udev_exit = 1;
 791                         break;
 792                 case SIGCHLD:
 793                         /* set flag, then write to pipe if needed */
 794                         sigchilds_waiting = 1;
 795                         break;
 796                 case SIGHUP:
 797                         reload_config = 1;
 798                         break;
 799         }
 800
 801         /* write to pipe, which will wakeup select() in our mainloop */
 802         write(signal_pipe[WRITE_END], "", 1);
 803 }
 804
 805 static void udev_done(int pid, int exitstatus)
 806 {
 807         /* find msg associated with pid and delete it */
 808         struct udevd_uevent_msg *msg;
 809
 810         list_for_each_entry(msg, &running_list, node) {
 811                 if (msg->pid == pid) {
 812                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 813                              exitstatus, time(NULL) - msg->queue_time);
 814                         msg->exitstatus = exitstatus;
 815                         msg_queue_delete(msg);
 816
 817                         /* there may be events waiting with the same devpath */
 818                         run_exec_q = 1;
 819                         return;
 820                 }
 821         }
 822 }
 823
 824 static void reap_sigchilds(void)
 825 {
 826         pid_t pid;
 827         int status;
 828
 829         while (1) {
 830                 pid = waitpid(-1, &status, WNOHANG);
 831                 if (pid <= 0)
 832                         break;
 833                 if (WIFEXITED(status))
 834                         status = WEXITSTATUS(status);
 835                 else if (WIFSIGNALED(status))
 836                         status = WTERMSIG(status) + 128;
 837                 else
 838                         status = 0;
 839                 udev_done(pid, status);
 840         }
 841 }
 842
 843 static int init_udevd_socket(void)
 844 {
 845         struct sockaddr_un saddr;
 846         socklen_t addrlen;
 847         const int feature_on = 1;
 848         int retval;
 849
 850         memset(&saddr, 0x00, sizeof(saddr));
 851         saddr.sun_family = AF_LOCAL;
 852         /* use abstract namespace for socket path */
 853         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 854         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 855
 856         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 857         if (udevd_sock == -1) {
 858                 err("error getting socket: %s", strerror(errno));
 859                 return -1;
 860         }
 861
 862         /* the bind takes care of ensuring only one copy running */
 863         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 864         if (retval < 0) {
 865                 err("bind failed: %s", strerror(errno));
 866                 close(udevd_sock);
 867                 udevd_sock = -1;
 868                 return -1;
 869         }
 870
 871         /* enable receiving of the sender credentials */
 872         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 873
 874         return 0;
 875 }
 876
 877 static int init_uevent_netlink_sock(void)
 878 {
 879         struct sockaddr_nl snl;
 880         const int buffersize = 16 * 1024 * 1024;
 881         int retval;
 882
 883         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 884         snl.nl_family = AF_NETLINK;
 885         snl.nl_pid = getpid();
 886         snl.nl_groups = 1;
 887
 888         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 889         if (uevent_netlink_sock == -1) {
 890                 err("error getting socket: %s", strerror(errno));
 891                 return -1;
 892         }
 893
 894         /* set receive buffersize */
 895         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 896
 897         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 898         if (retval < 0) {
 899                 err("bind failed: %s", strerror(errno));
 900                 close(uevent_netlink_sock);
 901                 uevent_netlink_sock = -1;
 902                 return -1;
 903         }
 904         return 0;
 905 }
 906
 907 static void export_initial_seqnum(void)
 908 {
 909         char filename[PATH_SIZE];
 910         int fd;
 911         char seqnum[32];
 912         ssize_t len = 0;
 913
 914         strlcpy(filename, sysfs_path, sizeof(filename));
 915         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 916         fd = open(filename, O_RDONLY);
 917         if (fd >= 0) {
 918                 len = read(fd, seqnum, sizeof(seqnum)-1);
 919                 close(fd);
 920         }
 921         if (len <= 0) {
 922                 strcpy(seqnum, "0\n");
 923                 len = 3;
 924         }
 925         strlcpy(filename, udev_root, sizeof(filename));
 926         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 927         create_path(filename);
 928         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 929         if (fd >= 0) {
 930                 write(fd, seqnum, len);
 931                 close(fd);
 932         }
 933 }
 934
 935 int main(int argc, char *argv[], char *envp[])
 936 {
 937         int retval;
 938         int fd;
 939         struct sigaction act;
 940         fd_set readfds;
 941         const char *value;
 942         int daemonize = 0;
 943         int option;
 944         static const struct option options[] = {
 945                 { "daemon", 0, NULL, 'd' },
 946                 { "debug-trace", 0, NULL, 't' },
 947                 { "verbose", 0, NULL, 'v' },
 948                 { "help", 0, NULL, 'h' },
 949                 { "version", 0, NULL, 'V' },
 950                 {}
 951         };
 952         int rc = 1;
 953         int maxfd;
 954
 955         logging_init("udevd");
 956         udev_config_init();
 957         selinux_init();
 958         dbg("version %s", UDEV_VERSION);
 959
 960         /* parse commandline options */
 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 }