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