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 verbose;
  49
  50 static struct udev_rules rules;
  51 static int udevd_sock = -1;
  52 static int uevent_netlink_sock = -1;
  53 static int inotify_fd = -1;
  54 static pid_t sid;
  55
  56 static int signal_pipe[2] = {-1, -1};
  57 static volatile int sigchilds_waiting;
  58 static volatile int udev_exit;
  59 static volatile int reload_config;
  60 static int run_exec_q;
  61 static int stop_exec_q;
  62 static int max_childs;
  63 static int max_childs_running;
  64 static char udev_log[32];
  65
  66 static LIST_HEAD(exec_list);
  67 static LIST_HEAD(running_list);
  68
  69
  70 #ifdef USE_LOG
  71 void log_message(int priority, const char *format, ...)
  72 {
  73         va_list args;
  74
  75         if (priority > udev_log_priority)
  76                 return;
  77
  78         va_start(args, format);
  79         vsyslog(priority, format, args);
  80         va_end(args);
  81
  82         if (verbose) {
  83                 va_start(args, format);
  84                 vprintf(format, args);
  85                 va_end(args);
  86                 printf("\n");
  87         }
  88 }
  89
  90 #endif
  91
  92 static void asmlinkage udev_event_sig_handler(int signum)
  93 {
  94         if (signum == SIGALRM)
  95                 exit(1);
  96 }
  97
  98 static int udev_event_process(struct udevd_uevent_msg *msg)
  99 {
 100         struct sigaction act;
 101         struct udevice *udev;
 102         int i;
 103         int retval;
 104
 105         /* set signal handlers */
 106         memset(&act, 0x00, sizeof(act));
 107         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 108         sigemptyset (&act.sa_mask);
 109         act.sa_flags = 0;
 110         sigaction(SIGALRM, &act, NULL);
 111
 112         /* reset to default */
 113         act.sa_handler = SIG_DFL;
 114         sigaction(SIGINT, &act, NULL);
 115         sigaction(SIGTERM, &act, NULL);
 116         sigaction(SIGCHLD, &act, NULL);
 117         sigaction(SIGHUP, &act, NULL);
 118
 119         /* trigger timeout to prevent hanging processes */
 120         alarm(UDEV_ALARM_TIMEOUT);
 121
 122         /* reconstruct event environment from message */
 123         for (i = 0; msg->envp[i]; i++)
 124                 putenv(msg->envp[i]);
 125
 126         udev = udev_device_init();
 127         if (udev == NULL)
 128                 return -1;
 129         strlcpy(udev->action, msg->action, sizeof(udev->action));
 130         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 131         udev->devt = msg->devt;
 132
 133         retval = udev_device_event(&rules, udev);
 134
 135         /* run programs collected by RUN-key*/
 136         if (retval == 0 && !udev->ignore_device && udev_run) {
 137                 struct name_entry *name_loop;
 138
 139                 dbg("executing run list");
 140                 list_for_each_entry(name_loop, &udev->run_list, node) {
 141                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 142                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 143                         else {
 144                                 char program[PATH_SIZE];
 145
 146                                 strlcpy(program, name_loop->name, sizeof(program));
 147                                 udev_rules_apply_format(udev, program, sizeof(program));
 148                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 149                                                 (udev_log_priority >= LOG_INFO)))
 150                                         retval = -1;
 151                         }
 152                 }
 153         }
 154
 155         udev_device_cleanup(udev);
 156         return retval;
 157 }
 158
 159 enum event_state {
 160         EVENT_QUEUED,
 161         EVENT_FINISHED,
 162         EVENT_FAILED,
 163 };
 164
 165 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 166 {
 167         char filename[PATH_SIZE];
 168         char filename_failed[PATH_SIZE];
 169         size_t start, end, i;
 170         struct udevd_uevent_msg *loop_msg;
 171         int fd;
 172
 173         /* add location of queue files */
 174         strlcpy(filename, udev_root, sizeof(filename));
 175         strlcat(filename, "/", sizeof(filename));
 176         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 177         end = strlcat(filename, msg->devpath, sizeof(filename));
 178         if (end > sizeof(filename))
 179                 end = sizeof(filename);
 180
 181         /* replace '/' to transform path into a filename */
 182         for (i = start+1; i < end; i++)
 183                 if (filename[i] == '/')
 184                         filename[i] = PATH_TO_NAME_CHAR;
 185
 186         /* add location of failed files */
 187         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 188         strlcat(filename_failed, "/", sizeof(filename_failed));
 189         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 190         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 191         if (end > sizeof(filename_failed))
 192                 end = sizeof(filename_failed);
 193
 194         /* replace '/' to transform path into a filename */
 195         for (i = start+1; i < end; i++)
 196                 if (filename_failed[i] == '/')
 197                         filename_failed[i] = PATH_TO_NAME_CHAR;
 198
 199         switch (state) {
 200         case EVENT_QUEUED:
 201                 unlink(filename_failed);
 202                 delete_path(filename_failed);
 203                 create_path(filename);
 204                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 205                 if (fd > 0)
 206                         close(fd);
 207                 return;
 208         case EVENT_FINISHED:
 209         case EVENT_FAILED:
 210                 unlink(filename_failed);
 211                 delete_path(filename_failed);
 212
 213                 /* don't remove, if events for the same path are still pending */
 214                 list_for_each_entry(loop_msg, &running_list, node)
 215                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 216                                 return;
 217
 218                 list_for_each_entry(loop_msg, &exec_list, node)
 219                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 220                                 return;
 221
 222                 /* move failed events to the failed directory */
 223                 if (state == EVENT_FAILED) {
 224                         create_path(filename_failed);
 225                         rename(filename, filename_failed);
 226                 } else {
 227                         unlink(filename);
 228                 }
 229
 230                 /* clean up the queue directory */
 231                 delete_path(filename);
 232
 233                 return;
 234         }
 235 }
 236
 237 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 238 {
 239         list_del(&msg->node);
 240
 241         /* mark as failed, if add event returns non-zero */
 242         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 243                 export_event_state(msg, EVENT_FAILED);
 244         else
 245                 export_event_state(msg, EVENT_FINISHED);
 246
 247         free(msg);
 248 }
 249
 250 static void udev_event_run(struct udevd_uevent_msg *msg)
 251 {
 252         pid_t pid;
 253         int retval;
 254
 255         pid = fork();
 256         switch (pid) {
 257         case 0:
 258                 /* child */
 259                 close(uevent_netlink_sock);
 260                 close(udevd_sock);
 261                 if (inotify_fd >= 0)
 262                         close(inotify_fd);
 263                 close(signal_pipe[READ_END]);
 264                 close(signal_pipe[WRITE_END]);
 265                 logging_close();
 266
 267                 logging_init("udevd-event");
 268                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 269
 270                 retval = udev_event_process(msg);
 271                 info("seq %llu finished", msg->seqnum);
 272
 273                 logging_close();
 274                 if (retval)
 275                         exit(1);
 276                 exit(0);
 277         case -1:
 278                 err("fork of child failed: %s", strerror(errno));
 279                 msg_queue_delete(msg);
 280                 break;
 281         default:
 282                 /* get SIGCHLD in main loop */
 283                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 284                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 285                 msg->pid = pid;
 286         }
 287 }
 288
 289 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 290 {
 291         char filename[PATH_SIZE];
 292         int fd;
 293
 294         msg->queue_time = time(NULL);
 295
 296         strlcpy(filename, udev_root, sizeof(filename));
 297         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 298         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 299         if (fd >= 0) {
 300                 char str[32];
 301                 int len;
 302
 303                 len = sprintf(str, "%llu\n", msg->seqnum);
 304                 write(fd, str, len);
 305                 close(fd);
 306         }
 307
 308         export_event_state(msg, EVENT_QUEUED);
 309
 310         /* run all events with a timeout set immediately */
 311         if (msg->timeout != 0) {
 312                 list_add_tail(&msg->node, &running_list);
 313                 udev_event_run(msg);
 314                 return;
 315         }
 316
 317         list_add_tail(&msg->node, &exec_list);
 318         run_exec_q = 1;
 319 }
 320
 321 static int mem_size_mb(void)
 322 {
 323         int f;
 324         char buf[8192];
 325         long int len;
 326         const char *pos;
 327         long int memsize;
 328
 329         f = open("/proc/meminfo", O_RDONLY);
 330         if (f == -1)
 331                 return -1;
 332
 333         len = read(f, buf, sizeof(buf)-1);
 334         close(f);
 335
 336         if (len <= 0)
 337                 return -1;
 338         buf[len] = '\0';
 339
 340         pos = strstr(buf, "MemTotal: ");
 341         if (pos == NULL)
 342                 return -1;
 343
 344         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 345                 return -1;
 346
 347         return memsize / 1024;
 348 }
 349
 350 static int cpu_count(void)
 351 {
 352         int f;
 353         char buf[32768];
 354         int len;
 355         const char *pos;
 356         int count = 0;
 357
 358         f = open("/proc/stat", O_RDONLY);
 359         if (f == -1)
 360                 return -1;
 361
 362         len = read(f, buf, sizeof(buf)-1);
 363         close(f);
 364         if (len <= 0)
 365                 return -1;
 366         buf[len] = '\0';
 367
 368         pos = strstr(buf, "cpu");
 369         if (pos == NULL)
 370                 return -1;
 371
 372         while (pos != NULL) {
 373                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 374                         count++;
 375                 pos = strstr(&pos[3], "cpu");
 376         }
 377
 378         if (count == 0)
 379                 return -1;
 380         return count;
 381 }
 382
 383 static int running_processes(void)
 384 {
 385         int f;
 386         char buf[32768];
 387         int len;
 388         int running;
 389         const char *pos;
 390
 391         f = open("/proc/stat", O_RDONLY);
 392         if (f == -1)
 393                 return -1;
 394
 395         len = read(f, buf, sizeof(buf)-1);
 396         close(f);
 397         if (len <= 0)
 398                 return -1;
 399         buf[len] = '\0';
 400
 401         pos = strstr(buf, "procs_running ");
 402         if (pos == NULL)
 403                 return -1;
 404
 405         if (sscanf(pos, "procs_running %u", &running) != 1)
 406                 return -1;
 407
 408         return running;
 409 }
 410
 411 /* return the number of process es in our session, count only until limit */
 412 static int running_processes_in_session(pid_t session, int limit)
 413 {
 414         DIR *dir;
 415         struct dirent *dent;
 416         int running = 0;
 417
 418         dir = opendir("/proc");
 419         if (!dir)
 420                 return -1;
 421
 422         /* read process info from /proc */
 423         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 424                 int f;
 425                 char procdir[64];
 426                 char line[256];
 427                 const char *pos;
 428                 char state;
 429                 pid_t ppid, pgrp, sess;
 430                 int len;
 431
 432                 if (!isdigit(dent->d_name[0]))
 433                         continue;
 434
 435                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 436                 procdir[sizeof(procdir)-1] = '\0';
 437
 438                 f = open(procdir, O_RDONLY);
 439                 if (f == -1)
 440                         continue;
 441
 442                 len = read(f, line, sizeof(line)-1);
 443                 close(f);
 444
 445                 if (len <= 0)
 446                         continue;
 447                 else
 448                         line[len] = '\0';
 449
 450                 /* skip ugly program name */
 451                 pos = strrchr(line, ')') + 2;
 452                 if (pos == NULL)
 453                         continue;
 454
 455                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 456                         continue;
 457
 458                 /* count only processes in our session */
 459                 if (sess != session)
 460                         continue;
 461
 462                 /* count only running, no sleeping processes */
 463                 if (state != 'R')
 464                         continue;
 465
 466                 running++;
 467                 if (limit > 0 && running >= limit)
 468                         break;
 469         }
 470         closedir(dir);
 471
 472         return running;
 473 }
 474
 475 static int compare_devpath(const char *running, const char *waiting)
 476 {
 477         int i;
 478
 479         for (i = 0; i < PATH_SIZE; i++) {
 480                 /* identical device event found */
 481                 if (running[i] == '\0' && waiting[i] == '\0')
 482                         return 1;
 483
 484                 /* parent device event found */
 485                 if (running[i] == '\0' && waiting[i] == '/')
 486                         return 2;
 487
 488                 /* child device event found */
 489                 if (running[i] == '/' && waiting[i] == '\0')
 490                         return 3;
 491
 492                 /* no matching event */
 493                 if (running[i] != waiting[i])
 494                         break;
 495         }
 496
 497         return 0;
 498 }
 499
 500 /* returns still running task for the same device, its parent or its physical device */
 501 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 502 {
 503         struct udevd_uevent_msg *loop_msg;
 504         int childs_count = 0;
 505
 506         list_for_each_entry(loop_msg, &running_list, node) {
 507                 if (limit && childs_count++ > limit) {
 508                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 509                         return 1;
 510                 }
 511
 512                 /* return running parent/child device event */
 513                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 514                         dbg("%llu, child device event still running %llu (%s)",
 515                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 516                         return 2;
 517                 }
 518
 519                 /* return running physical device event */
 520                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 521                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 522                                 dbg("%llu, physical device event still running %llu (%s)",
 523                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 524                                 return 3;
 525                         }
 526         }
 527
 528         return 0;
 529 }
 530
 531 /* exec queue management routine executes the events and serializes events in the same sequence */
 532 static void msg_queue_manager(void)
 533 {
 534         struct udevd_uevent_msg *loop_msg;
 535         struct udevd_uevent_msg *tmp_msg;
 536         int running;
 537
 538         if (list_empty(&exec_list))
 539                 return;
 540
 541         running = running_processes();
 542         dbg("%d processes runnning on system", running);
 543         if (running < 0)
 544                 running = max_childs_running;
 545
 546         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 547                 /* check running processes in our session and possibly throttle */
 548                 if (running >= max_childs_running) {
 549                         running = running_processes_in_session(sid, max_childs_running+10);
 550                         dbg("at least %d processes running in session", running);
 551                         if (running >= max_childs_running) {
 552                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 553                                 return;
 554                         }
 555                 }
 556
 557                 /* don't run two processes for the same devpath and wait for the parent*/
 558                 if (running_with_devpath(loop_msg, max_childs)) {
 559                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 560                         continue;
 561                 }
 562
 563                 /* move event to run list */
 564                 list_move_tail(&loop_msg->node, &running_list);
 565                 udev_event_run(loop_msg);
 566                 running++;
 567                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 568         }
 569 }
 570
 571 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 572 {
 573         int bufpos;
 574         int i;
 575         struct udevd_uevent_msg *msg;
 576         char *physdevdriver_key = NULL;
 577         int maj = 0;
 578         int min = 0;
 579
 580         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 581         if (msg == NULL)
 582                 return NULL;
 583         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 584
 585         /* copy environment buffer and reconstruct envp */
 586         memcpy(msg->envbuf, buf, buf_size);
 587         bufpos = 0;
 588         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 589                 int keylen;
 590                 char *key;
 591
 592                 key = &msg->envbuf[bufpos];
 593                 keylen = strlen(key);
 594                 msg->envp[i] = key;
 595                 bufpos += keylen + 1;
 596                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 597
 598                 /* remember some keys for further processing */
 599                 if (strncmp(key, "ACTION=", 7) == 0)
 600                         msg->action = &key[7];
 601                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 602                         msg->devpath = &key[8];
 603                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 604                         msg->subsystem = &key[10];
 605                 else if (strncmp(key, "DRIVER=", 7) == 0)
 606                         msg->driver = &key[7];
 607                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 608                         msg->seqnum = strtoull(&key[7], NULL, 10);
 609                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 610                         msg->physdevpath = &key[12];
 611                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 612                         physdevdriver_key = key;
 613                 else if (strncmp(key, "MAJOR=", 6) == 0)
 614                         maj = strtoull(&key[6], NULL, 10);
 615                 else if (strncmp(key, "MINOR=", 6) == 0)
 616                         min = strtoull(&key[6], NULL, 10);
 617                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 618                         msg->timeout = strtoull(&key[8], NULL, 10);
 619         }
 620         msg->devt = makedev(maj, min);
 621         msg->envp[i++] = "UDEVD_EVENT=1";
 622
 623         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 624                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 625                 msg->envp[i++] = &physdevdriver_key[7];
 626                 msg->driver = &physdevdriver_key[14];
 627         }
 628
 629         msg->envp[i] = NULL;
 630
 631         if (msg->devpath == NULL || msg->action == NULL) {
 632                 info("DEVPATH or ACTION missing, ignore message");
 633                 free(msg);
 634                 return NULL;
 635         }
 636         return msg;
 637 }
 638
 639 /* receive the udevd message from userspace */
 640 static void get_ctrl_msg(void)
 641 {
 642         struct udevd_ctrl_msg ctrl_msg;
 643         ssize_t size;
 644         struct msghdr smsg;
 645         struct cmsghdr *cmsg;
 646         struct iovec iov;
 647         struct ucred *cred;
 648         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 649         int *intval;
 650
 651         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 652         iov.iov_base = &ctrl_msg;
 653         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 654
 655         memset(&smsg, 0x00, sizeof(struct msghdr));
 656         smsg.msg_iov = &iov;
 657         smsg.msg_iovlen = 1;
 658         smsg.msg_control = cred_msg;
 659         smsg.msg_controllen = sizeof(cred_msg);
 660
 661         size = recvmsg(udevd_sock, &smsg, 0);
 662         if (size <  0) {
 663                 if (errno != EINTR)
 664                         err("unable to receive user udevd message: %s", strerror(errno));
 665                 return;
 666         }
 667         cmsg = CMSG_FIRSTHDR(&smsg);
 668         cred = (struct ucred *) CMSG_DATA(cmsg);
 669
 670         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 671                 err("no sender credentials received, message ignored");
 672                 return;
 673         }
 674
 675         if (cred->uid != 0) {
 676                 err("sender uid=%i, message ignored", cred->uid);
 677                 return;
 678         }
 679
 680         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 681                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 682                 return;
 683         }
 684
 685         switch (ctrl_msg.type) {
 686         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 687                 info("udevd message (STOP_EXEC_QUEUE) received");
 688                 stop_exec_q = 1;
 689                 break;
 690         case UDEVD_CTRL_START_EXEC_QUEUE:
 691                 info("udevd message (START_EXEC_QUEUE) received");
 692                 stop_exec_q = 0;
 693                 msg_queue_manager();
 694                 break;
 695         case UDEVD_CTRL_SET_LOG_LEVEL:
 696                 intval = (int *) ctrl_msg.buf;
 697                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 698                 udev_log_priority = *intval;
 699                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 700                 putenv(udev_log);
 701                 break;
 702         case UDEVD_CTRL_SET_MAX_CHILDS:
 703                 intval = (int *) ctrl_msg.buf;
 704                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 705                 max_childs = *intval;
 706                 break;
 707         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 708                 intval = (int *) ctrl_msg.buf;
 709                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 710                 max_childs_running = *intval;
 711                 break;
 712         case UDEVD_CTRL_RELOAD_RULES:
 713                 info("udevd message (RELOAD_RULES) received");
 714                 reload_config = 1;
 715                 break;
 716         default:
 717                 err("unknown control message type");
 718         }
 719 }
 720
 721 /* receive the kernel user event message and do some sanity checks */
 722 static struct udevd_uevent_msg *get_netlink_msg(void)
 723 {
 724         struct udevd_uevent_msg *msg;
 725         int bufpos;
 726         ssize_t size;
 727         static char buffer[UEVENT_BUFFER_SIZE+512];
 728         char *pos;
 729
 730         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 731         if (size <  0) {
 732                 if (errno != EINTR)
 733                         err("unable to receive kernel netlink message: %s", strerror(errno));
 734                 return NULL;
 735         }
 736
 737         if ((size_t)size > sizeof(buffer)-1)
 738                 size = sizeof(buffer)-1;
 739         buffer[size] = '\0';
 740         dbg("uevent_size=%zi", size);
 741
 742         /* start of event payload */
 743         bufpos = strlen(buffer)+1;
 744         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 745         if (msg == NULL)
 746                 return NULL;
 747
 748         /* validate message */
 749         pos = strchr(buffer, '@');
 750         if (pos == NULL) {
 751                 err("invalid uevent '%s'", buffer);
 752                 free(msg);
 753                 return NULL;
 754         }
 755         pos[0] = '\0';
 756
 757         if (msg->action == NULL) {
 758                 info("no ACTION in payload found, skip event '%s'", buffer);
 759                 free(msg);
 760                 return NULL;
 761         }
 762
 763         if (strcmp(msg->action, buffer) != 0) {
 764                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 765                 free(msg);
 766                 return NULL;
 767         }
 768
 769         return msg;
 770 }
 771
 772 static void asmlinkage sig_handler(int signum)
 773 {
 774         switch (signum) {
 775                 case SIGINT:
 776                 case SIGTERM:
 777                         udev_exit = 1;
 778                         break;
 779                 case SIGCHLD:
 780                         /* set flag, then write to pipe if needed */
 781                         sigchilds_waiting = 1;
 782                         break;
 783                 case SIGHUP:
 784                         reload_config = 1;
 785                         break;
 786         }
 787
 788         /* write to pipe, which will wakeup select() in our mainloop */
 789         write(signal_pipe[WRITE_END], "", 1);
 790 }
 791
 792 static void udev_done(int pid, int exitstatus)
 793 {
 794         /* find msg associated with pid and delete it */
 795         struct udevd_uevent_msg *msg;
 796
 797         list_for_each_entry(msg, &running_list, node) {
 798                 if (msg->pid == pid) {
 799                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 800                              exitstatus, time(NULL) - msg->queue_time);
 801                         msg->exitstatus = exitstatus;
 802                         msg_queue_delete(msg);
 803
 804                         /* there may be events waiting with the same devpath */
 805                         run_exec_q = 1;
 806                         return;
 807                 }
 808         }
 809 }
 810
 811 static void reap_sigchilds(void)
 812 {
 813         pid_t pid;
 814         int status;
 815
 816         while (1) {
 817                 pid = waitpid(-1, &status, WNOHANG);
 818                 if (pid <= 0)
 819                         break;
 820                 if (WIFEXITED(status))
 821                         status = WEXITSTATUS(status);
 822                 else if (WIFSIGNALED(status))
 823                         status = WTERMSIG(status) + 128;
 824                 else
 825                         status = 0;
 826                 udev_done(pid, status);
 827         }
 828 }
 829
 830 static int init_udevd_socket(void)
 831 {
 832         struct sockaddr_un saddr;
 833         socklen_t addrlen;
 834         const int feature_on = 1;
 835         int retval;
 836
 837         memset(&saddr, 0x00, sizeof(saddr));
 838         saddr.sun_family = AF_LOCAL;
 839         /* use abstract namespace for socket path */
 840         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 841         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 842
 843         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 844         if (udevd_sock == -1) {
 845                 err("error getting socket: %s", strerror(errno));
 846                 return -1;
 847         }
 848
 849         /* the bind takes care of ensuring only one copy running */
 850         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 851         if (retval < 0) {
 852                 err("bind failed: %s", strerror(errno));
 853                 close(udevd_sock);
 854                 udevd_sock = -1;
 855                 return -1;
 856         }
 857
 858         /* enable receiving of the sender credentials */
 859         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 860
 861         return 0;
 862 }
 863
 864 static int init_uevent_netlink_sock(void)
 865 {
 866         struct sockaddr_nl snl;
 867         const int buffersize = 16 * 1024 * 1024;
 868         int retval;
 869
 870         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 871         snl.nl_family = AF_NETLINK;
 872         snl.nl_pid = getpid();
 873         snl.nl_groups = 1;
 874
 875         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 876         if (uevent_netlink_sock == -1) {
 877                 err("error getting socket: %s", strerror(errno));
 878                 return -1;
 879         }
 880
 881         /* set receive buffersize */
 882         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 883
 884         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 885         if (retval < 0) {
 886                 err("bind failed: %s", strerror(errno));
 887                 close(uevent_netlink_sock);
 888                 uevent_netlink_sock = -1;
 889                 return -1;
 890         }
 891         return 0;
 892 }
 893
 894 static void export_initial_seqnum(void)
 895 {
 896         char filename[PATH_SIZE];
 897         int fd;
 898         char seqnum[32];
 899         ssize_t len = 0;
 900
 901         strlcpy(filename, sysfs_path, sizeof(filename));
 902         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 903         fd = open(filename, O_RDONLY);
 904         if (fd >= 0) {
 905                 len = read(fd, seqnum, sizeof(seqnum)-1);
 906                 close(fd);
 907         }
 908         if (len <= 0) {
 909                 strcpy(seqnum, "0\n");
 910                 len = 3;
 911         }
 912         strlcpy(filename, udev_root, sizeof(filename));
 913         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 914         create_path(filename);
 915         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 916         if (fd >= 0) {
 917                 write(fd, seqnum, len);
 918                 close(fd);
 919         }
 920 }
 921
 922 int main(int argc, char *argv[], char *envp[])
 923 {
 924         int retval;
 925         int fd;
 926         struct sigaction act;
 927         fd_set readfds;
 928         const char *value;
 929         int daemonize = 0;
 930         int option;
 931         static const struct option options[] = {
 932                 { "daemon", 0, NULL, 'd' },
 933                 { "verbose", 0, NULL, 'v' },
 934                 { "help", 0, NULL, 'h' },
 935                 {}
 936         };
 937         int rc = 1;
 938         int maxfd;
 939
 940         logging_init("udevd");
 941         udev_config_init();
 942         selinux_init();
 943         dbg("version %s", UDEV_VERSION);
 944
 945         /* parse commandline options */
 946         while (1) {
 947                 option = getopt_long(argc, argv, "dtvh", options, NULL);
 948                 if (option == -1)
 949                         break;
 950
 951                 switch (option) {
 952                 case 'd':
 953                         daemonize = 1;
 954                         break;
 955                 case 'v':
 956                         verbose = 1;
 957                         if (udev_log_priority < LOG_INFO)
 958                                 udev_log_priority = LOG_INFO;
 959                         break;
 960                 case 'h':
 961                         printf("Usage: udevd [--help] [--daemon] [--verbose]\n");
 962                         goto exit;
 963                 default:
 964                         goto exit;
 965                 }
 966         }
 967
 968         if (getuid() != 0) {
 969                 fprintf(stderr, "root privileges required\n");
 970                 err("root privileges required");
 971                 goto exit;
 972         }
 973
 974         /* init sockets to receive events */
 975         if (init_udevd_socket() < 0) {
 976                 if (errno == EADDRINUSE) {
 977                         fprintf(stderr, "another udev daemon already running\n");
 978                         err("another udev daemon already running");
 979                         rc = 1;
 980                 } else {
 981                         fprintf(stderr, "error initializing udevd socket\n");
 982                         err("error initializing udevd socket");
 983                         rc = 2;
 984                 }
 985                 goto exit;
 986         }
 987
 988         if (init_uevent_netlink_sock() < 0) {
 989                 fprintf(stderr, "error initializing netlink socket\n");
 990                 err("error initializing netlink socket");
 991                 rc = 3;
 992                 goto exit;
 993         }
 994
 995         /* parse the rules and keep them in memory */
 996         sysfs_init();
 997         udev_rules_init(&rules, 1);
 998
 999         export_initial_seqnum();
1000
1001         if (daemonize) {
1002                 pid_t pid;
1003
1004                 pid = fork();
1005                 switch (pid) {
1006                 case 0:
1007                         dbg("daemonized fork running");
1008                         break;
1009                 case -1:
1010                         err("fork of daemon failed: %s", strerror(errno));
1011                         rc = 4;
1012                         goto exit;
1013                 default:
1014                         dbg("child [%u] running, parent exits", pid);
1015                         rc = 0;
1016                         goto exit;
1017                 }
1018         }
1019
1020         /* redirect std fd's */
1021         fd = open("/dev/null", O_RDWR);
1022         if (fd >= 0) {
1023                 dup2(fd, STDIN_FILENO);
1024                 if (!verbose)
1025                         dup2(fd, STDOUT_FILENO);
1026                 dup2(fd, STDERR_FILENO);
1027                 if (fd > STDERR_FILENO)
1028                         close(fd);
1029         } else
1030                 err("error opening /dev/null: %s", strerror(errno));
1031
1032         /* set scheduling priority for the daemon */
1033         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1034
1035         chdir("/");
1036         umask(022);
1037
1038         /* become session leader */
1039         sid = setsid();
1040         dbg("our session is %d", sid);
1041
1042         /* OOM_DISABLE == -17 */
1043         fd = open("/proc/self/oom_adj", O_RDWR);
1044         if (fd < 0)
1045                 err("error disabling OOM: %s", strerror(errno));
1046         else {
1047                 write(fd, "-17", 3);
1048                 close(fd);
1049         }
1050
1051         /* setup signal handler pipe */
1052         retval = pipe(signal_pipe);
1053         if (retval < 0) {
1054                 err("error getting pipes: %s", strerror(errno));
1055                 goto exit;
1056         }
1057
1058         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1059         if (retval < 0) {
1060                 err("error fcntl on read pipe: %s", strerror(errno));
1061                 goto exit;
1062         }
1063         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1064         if (retval < 0) {
1065                 err("error fcntl on read pipe: %s", strerror(errno));
1066                 goto exit;
1067         }
1068
1069         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1070         if (retval < 0) {
1071                 err("error fcntl on write pipe: %s", strerror(errno));
1072                 goto exit;
1073         }
1074         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1075         if (retval < 0) {
1076                 err("error fcntl on write pipe: %s", strerror(errno));
1077                 goto exit;
1078         }
1079
1080         /* set signal handlers */
1081         memset(&act, 0x00, sizeof(struct sigaction));
1082         act.sa_handler = (void (*)(int)) sig_handler;
1083         sigemptyset(&act.sa_mask);
1084         act.sa_flags = SA_RESTART;
1085         sigaction(SIGINT, &act, NULL);
1086         sigaction(SIGTERM, &act, NULL);
1087         sigaction(SIGCHLD, &act, NULL);
1088         sigaction(SIGHUP, &act, NULL);
1089
1090         /* watch rules directory */
1091         inotify_fd = inotify_init();
1092         if (inotify_fd >= 0)
1093                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1094         else if (errno == ENOSYS)
1095                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1096         else
1097                 err("inotify_init failed: %s", strerror(errno));
1098
1099         /* maximum limit of forked childs */
1100         value = getenv("UDEVD_MAX_CHILDS");
1101         if (value)
1102                 max_childs = strtoul(value, NULL, 10);
1103         else {
1104                 int memsize = mem_size_mb();
1105                 if (memsize > 0)
1106                         max_childs = 128 + (memsize / 4);
1107                 else
1108                         max_childs = UDEVD_MAX_CHILDS;
1109         }
1110         info("initialize max_childs to %u", max_childs);
1111
1112         /* start to throttle forking if maximum number of _running_ childs is reached */
1113         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1114         if (value)
1115                 max_childs_running = strtoull(value, NULL, 10);
1116         else {
1117                 int cpus = cpu_count();
1118                 if (cpus > 0)
1119                         max_childs_running = 8 + (8 * cpus);
1120                 else
1121                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1122         }
1123         info("initialize max_childs_running to %u", max_childs_running);
1124
1125         /* clear environment for forked event processes */
1126         clearenv();
1127
1128         /* export log_priority , as called programs may want to follow that setting */
1129         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1130         putenv(udev_log);
1131
1132         maxfd = udevd_sock;
1133         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1134         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1135         maxfd = UDEV_MAX(maxfd, inotify_fd);
1136
1137         while (!udev_exit) {
1138                 struct udevd_uevent_msg *msg;
1139                 int fdcount;
1140
1141                 FD_ZERO(&readfds);
1142                 FD_SET(signal_pipe[READ_END], &readfds);
1143                 FD_SET(udevd_sock, &readfds);
1144                 FD_SET(uevent_netlink_sock, &readfds);
1145                 if (inotify_fd >= 0)
1146                         FD_SET(inotify_fd, &readfds);
1147
1148                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1149                 if (fdcount < 0) {
1150                         if (errno != EINTR)
1151                                 err("error in select: %s", strerror(errno));
1152                         continue;
1153                 }
1154
1155                 /* get control message */
1156                 if (FD_ISSET(udevd_sock, &readfds))
1157                         get_ctrl_msg();
1158
1159                 /* get netlink message */
1160                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1161                         msg = get_netlink_msg();
1162                         if (msg)
1163                                 msg_queue_insert(msg);
1164                 }
1165
1166                 /* received a signal, clear our notification pipe */
1167                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1168                         char buf[256];
1169
1170                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1171                 }
1172
1173                 /* rules directory inotify watch */
1174                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1175                         int nbytes;
1176
1177                         /* discard all possible events, we can just reload the config */
1178                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1179                                 char *buf;
1180
1181                                 reload_config = 1;
1182                                 buf = malloc(nbytes);
1183                                 if (!buf) {
1184                                         err("error getting buffer for inotify, disable watching");
1185                                         close(inotify_fd);
1186                                         inotify_fd = -1;
1187                                 }
1188                                 read(inotify_fd, buf, nbytes);
1189                                 free(buf);
1190                         }
1191                 }
1192
1193                 /* rules changed, set by inotify or a HUP signal */
1194                 if (reload_config) {
1195                         reload_config = 0;
1196                         udev_rules_cleanup(&rules);
1197                         udev_rules_init(&rules, 1);
1198                 }
1199
1200                 /* forked child has returned */
1201                 if (sigchilds_waiting) {
1202                         sigchilds_waiting = 0;
1203                         reap_sigchilds();
1204                 }
1205
1206                 if (run_exec_q) {
1207                         run_exec_q = 0;
1208                         if (!stop_exec_q)
1209                                 msg_queue_manager();
1210                 }
1211         }
1212         rc = 0;
1213
1214 exit:
1215         udev_rules_cleanup(&rules);
1216         sysfs_cleanup();
1217
1218         if (signal_pipe[READ_END] >= 0)
1219                 close(signal_pipe[READ_END]);
1220         if (signal_pipe[WRITE_END] >= 0)
1221                 close(signal_pipe[WRITE_END]);
1222
1223         if (udevd_sock >= 0)
1224                 close(udevd_sock);
1225         if (inotify_fd >= 0)
1226                 close(inotify_fd);
1227         if (uevent_netlink_sock >= 0)
1228                 close(uevent_netlink_sock);
1229
1230         logging_close();
1231
1232         return rc;
1233 }