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         int f;
 322         char buf[8192];
 323         long int len;
 324         const char *pos;
 325         long int memsize;
 326
 327         f = open("/proc/meminfo", O_RDONLY);
 328         if (f == -1)
 329                 return -1;
 330
 331         len = read(f, buf, sizeof(buf)-1);
 332         close(f);
 333
 334         if (len <= 0)
 335                 return -1;
 336         buf[len] = '\0';
 337
 338         pos = strstr(buf, "MemTotal: ");
 339         if (pos == NULL)
 340                 return -1;
 341
 342         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 343                 return -1;
 344
 345         return memsize / 1024;
 346 }
 347
 348 static int cpu_count(void)
 349 {
 350         int f;
 351         char buf[65536];
 352         int len;
 353         const char *pos;
 354         int count = 0;
 355
 356         f = open("/proc/stat", O_RDONLY);
 357         if (f == -1)
 358                 return -1;
 359
 360         len = read(f, buf, sizeof(buf)-1);
 361         close(f);
 362         if (len <= 0)
 363                 return -1;
 364         buf[len] = '\0';
 365
 366         pos = strstr(buf, "cpu");
 367         if (pos == NULL)
 368                 return -1;
 369
 370         while (pos != NULL) {
 371                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 372                         count++;
 373                 pos = strstr(&pos[3], "cpu");
 374         }
 375
 376         if (count == 0)
 377                 return -1;
 378         return count;
 379 }
 380
 381 static int running_processes(void)
 382 {
 383         int f;
 384         char buf[32768];
 385         int len;
 386         int running;
 387         const char *pos;
 388
 389         f = open("/proc/stat", O_RDONLY);
 390         if (f == -1)
 391                 return -1;
 392
 393         len = read(f, buf, sizeof(buf)-1);
 394         close(f);
 395         if (len <= 0)
 396                 return -1;
 397         buf[len] = '\0';
 398
 399         pos = strstr(buf, "procs_running ");
 400         if (pos == NULL)
 401                 return -1;
 402
 403         if (sscanf(pos, "procs_running %u", &running) != 1)
 404                 return -1;
 405
 406         return running;
 407 }
 408
 409 /* return the number of process es in our session, count only until limit */
 410 static int running_processes_in_session(pid_t session, int limit)
 411 {
 412         DIR *dir;
 413         struct dirent *dent;
 414         int running = 0;
 415
 416         dir = opendir("/proc");
 417         if (!dir)
 418                 return -1;
 419
 420         /* read process info from /proc */
 421         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 422                 int f;
 423                 char procdir[64];
 424                 char line[256];
 425                 const char *pos;
 426                 char state;
 427                 pid_t ppid, pgrp, sess;
 428                 int len;
 429
 430                 if (!isdigit(dent->d_name[0]))
 431                         continue;
 432
 433                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 434                 procdir[sizeof(procdir)-1] = '\0';
 435
 436                 f = open(procdir, O_RDONLY);
 437                 if (f == -1)
 438                         continue;
 439
 440                 len = read(f, line, sizeof(line)-1);
 441                 close(f);
 442
 443                 if (len <= 0)
 444                         continue;
 445                 else
 446                         line[len] = '\0';
 447
 448                 /* skip ugly program name */
 449                 pos = strrchr(line, ')') + 2;
 450                 if (pos == NULL)
 451                         continue;
 452
 453                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 454                         continue;
 455
 456                 /* count only processes in our session */
 457                 if (sess != session)
 458                         continue;
 459
 460                 /* count only running, no sleeping processes */
 461                 if (state != 'R')
 462                         continue;
 463
 464                 running++;
 465                 if (limit > 0 && running >= limit)
 466                         break;
 467         }
 468         closedir(dir);
 469
 470         return running;
 471 }
 472
 473 static int compare_devpath(const char *running, const char *waiting)
 474 {
 475         int i;
 476
 477         for (i = 0; i < PATH_SIZE; i++) {
 478                 /* identical device event found */
 479                 if (running[i] == '\0' && waiting[i] == '\0')
 480                         return 1;
 481
 482                 /* parent device event found */
 483                 if (running[i] == '\0' && waiting[i] == '/')
 484                         return 2;
 485
 486                 /* child device event found */
 487                 if (running[i] == '/' && waiting[i] == '\0')
 488                         return 3;
 489
 490                 /* no matching event */
 491                 if (running[i] != waiting[i])
 492                         break;
 493         }
 494
 495         return 0;
 496 }
 497
 498 /* lookup event for identical, parent, child, or physical device */
 499 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 500 {
 501         struct udevd_uevent_msg *loop_msg;
 502         int childs_count = 0;
 503
 504         /* check exec-queue which may still contain delayed events we depend on */
 505         list_for_each_entry(loop_msg, &exec_list, node) {
 506                 /* skip ourself and all later events */
 507                 if (loop_msg->seqnum >= msg->seqnum)
 508                         break;
 509
 510                 /* check identical, parent, or child device event */
 511                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 512                         dbg("%llu, device event still pending %llu (%s)",
 513                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 514                         return 2;
 515                 }
 516
 517                 /* check physical device event (special case of parent) */
 518                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 519                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 520                                 dbg("%llu, physical device event still pending %llu (%s)",
 521                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 522                                 return 3;
 523                         }
 524         }
 525
 526         /* check runing-queue for still running events */
 527         list_for_each_entry(loop_msg, &running_list, node) {
 528                 if (limit && childs_count++ > limit) {
 529                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 530                         return 1;
 531                 }
 532
 533                 /* check identical, parent, or child device event */
 534                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 535                         dbg("%llu, device event still running %llu (%s)",
 536                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 537                         return 2;
 538                 }
 539
 540                 /* check physical device event (special case of parent) */
 541                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 542                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 543                                 dbg("%llu, physical device event still running %llu (%s)",
 544                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 545                                 return 3;
 546                         }
 547         }
 548         return 0;
 549 }
 550
 551 /* serializes events for the identical and parent and child devices */
 552 static void msg_queue_manager(void)
 553 {
 554         struct udevd_uevent_msg *loop_msg;
 555         struct udevd_uevent_msg *tmp_msg;
 556         int running;
 557
 558         if (list_empty(&exec_list))
 559                 return;
 560
 561         running = running_processes();
 562         dbg("%d processes runnning on system", running);
 563         if (running < 0)
 564                 running = max_childs_running;
 565
 566         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 567                 /* check running processes in our session and possibly throttle */
 568                 if (running >= max_childs_running) {
 569                         running = running_processes_in_session(sid, max_childs_running+10);
 570                         dbg("at least %d processes running in session", running);
 571                         if (running >= max_childs_running) {
 572                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 573                                 return;
 574                         }
 575                 }
 576
 577                 /* serialize and wait for parent or child events */
 578                 if (devpath_busy(loop_msg, max_childs) != 0) {
 579                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 580                         continue;
 581                 }
 582
 583                 /* move event to run list */
 584                 list_move_tail(&loop_msg->node, &running_list);
 585                 udev_event_run(loop_msg);
 586                 running++;
 587                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 588         }
 589 }
 590
 591 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 592 {
 593         int bufpos;
 594         int i;
 595         struct udevd_uevent_msg *msg;
 596         char *physdevdriver_key = NULL;
 597         int maj = 0;
 598         int min = 0;
 599
 600         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 601         if (msg == NULL)
 602                 return NULL;
 603         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 604
 605         /* copy environment buffer and reconstruct envp */
 606         memcpy(msg->envbuf, buf, buf_size);
 607         bufpos = 0;
 608         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 609                 int keylen;
 610                 char *key;
 611
 612                 key = &msg->envbuf[bufpos];
 613                 keylen = strlen(key);
 614                 msg->envp[i] = key;
 615                 bufpos += keylen + 1;
 616                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 617
 618                 /* remember some keys for further processing */
 619                 if (strncmp(key, "ACTION=", 7) == 0)
 620                         msg->action = &key[7];
 621                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 622                         msg->devpath = &key[8];
 623                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 624                         msg->subsystem = &key[10];
 625                 else if (strncmp(key, "DRIVER=", 7) == 0)
 626                         msg->driver = &key[7];
 627                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 628                         msg->seqnum = strtoull(&key[7], NULL, 10);
 629                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 630                         msg->physdevpath = &key[12];
 631                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 632                         physdevdriver_key = key;
 633                 else if (strncmp(key, "MAJOR=", 6) == 0)
 634                         maj = strtoull(&key[6], NULL, 10);
 635                 else if (strncmp(key, "MINOR=", 6) == 0)
 636                         min = strtoull(&key[6], NULL, 10);
 637                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 638                         msg->timeout = strtoull(&key[8], NULL, 10);
 639         }
 640         msg->devt = makedev(maj, min);
 641         msg->envp[i++] = "UDEVD_EVENT=1";
 642
 643         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 644                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 645                 msg->envp[i++] = &physdevdriver_key[7];
 646                 msg->driver = &physdevdriver_key[14];
 647         }
 648
 649         msg->envp[i] = NULL;
 650
 651         if (msg->devpath == NULL || msg->action == NULL) {
 652                 info("DEVPATH or ACTION missing, ignore message");
 653                 free(msg);
 654                 return NULL;
 655         }
 656         return msg;
 657 }
 658
 659 /* receive the udevd message from userspace */
 660 static void get_ctrl_msg(void)
 661 {
 662         struct udevd_ctrl_msg ctrl_msg;
 663         ssize_t size;
 664         struct msghdr smsg;
 665         struct cmsghdr *cmsg;
 666         struct iovec iov;
 667         struct ucred *cred;
 668         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 669         int *intval;
 670
 671         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 672         iov.iov_base = &ctrl_msg;
 673         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 674
 675         memset(&smsg, 0x00, sizeof(struct msghdr));
 676         smsg.msg_iov = &iov;
 677         smsg.msg_iovlen = 1;
 678         smsg.msg_control = cred_msg;
 679         smsg.msg_controllen = sizeof(cred_msg);
 680
 681         size = recvmsg(udevd_sock, &smsg, 0);
 682         if (size <  0) {
 683                 if (errno != EINTR)
 684                         err("unable to receive user udevd message: %s", strerror(errno));
 685                 return;
 686         }
 687         cmsg = CMSG_FIRSTHDR(&smsg);
 688         cred = (struct ucred *) CMSG_DATA(cmsg);
 689
 690         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 691                 err("no sender credentials received, message ignored");
 692                 return;
 693         }
 694
 695         if (cred->uid != 0) {
 696                 err("sender uid=%i, message ignored", cred->uid);
 697                 return;
 698         }
 699
 700         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 701                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 702                 return;
 703         }
 704
 705         switch (ctrl_msg.type) {
 706         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 707                 info("udevd message (STOP_EXEC_QUEUE) received");
 708                 stop_exec_q = 1;
 709                 break;
 710         case UDEVD_CTRL_START_EXEC_QUEUE:
 711                 info("udevd message (START_EXEC_QUEUE) received");
 712                 stop_exec_q = 0;
 713                 msg_queue_manager();
 714                 break;
 715         case UDEVD_CTRL_SET_LOG_LEVEL:
 716                 intval = (int *) ctrl_msg.buf;
 717                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 718                 udev_log_priority = *intval;
 719                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 720                 putenv(udev_log);
 721                 break;
 722         case UDEVD_CTRL_SET_MAX_CHILDS:
 723                 intval = (int *) ctrl_msg.buf;
 724                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 725                 max_childs = *intval;
 726                 break;
 727         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 728                 intval = (int *) ctrl_msg.buf;
 729                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 730                 max_childs_running = *intval;
 731                 break;
 732         case UDEVD_CTRL_RELOAD_RULES:
 733                 info("udevd message (RELOAD_RULES) received");
 734                 reload_config = 1;
 735                 break;
 736         default:
 737                 err("unknown control message type");
 738         }
 739 }
 740
 741 /* receive the kernel user event message and do some sanity checks */
 742 static struct udevd_uevent_msg *get_netlink_msg(void)
 743 {
 744         struct udevd_uevent_msg *msg;
 745         int bufpos;
 746         ssize_t size;
 747         static char buffer[UEVENT_BUFFER_SIZE+512];
 748         char *pos;
 749
 750         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 751         if (size <  0) {
 752                 if (errno != EINTR)
 753                         err("unable to receive kernel netlink message: %s", strerror(errno));
 754                 return NULL;
 755         }
 756
 757         if ((size_t)size > sizeof(buffer)-1)
 758                 size = sizeof(buffer)-1;
 759         buffer[size] = '\0';
 760         dbg("uevent_size=%zi", size);
 761
 762         /* start of event payload */
 763         bufpos = strlen(buffer)+1;
 764         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 765         if (msg == NULL)
 766                 return NULL;
 767
 768         /* validate message */
 769         pos = strchr(buffer, '@');
 770         if (pos == NULL) {
 771                 err("invalid uevent '%s'", buffer);
 772                 free(msg);
 773                 return NULL;
 774         }
 775         pos[0] = '\0';
 776
 777         if (msg->action == NULL) {
 778                 info("no ACTION in payload found, skip event '%s'", buffer);
 779                 free(msg);
 780                 return NULL;
 781         }
 782
 783         if (strcmp(msg->action, buffer) != 0) {
 784                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 785                 free(msg);
 786                 return NULL;
 787         }
 788
 789         return msg;
 790 }
 791
 792 static void asmlinkage sig_handler(int signum)
 793 {
 794         switch (signum) {
 795                 case SIGINT:
 796                 case SIGTERM:
 797                         udev_exit = 1;
 798                         break;
 799                 case SIGCHLD:
 800                         /* set flag, then write to pipe if needed */
 801                         sigchilds_waiting = 1;
 802                         break;
 803                 case SIGHUP:
 804                         reload_config = 1;
 805                         break;
 806         }
 807
 808         /* write to pipe, which will wakeup select() in our mainloop */
 809         write(signal_pipe[WRITE_END], "", 1);
 810 }
 811
 812 static void udev_done(int pid, int exitstatus)
 813 {
 814         /* find msg associated with pid and delete it */
 815         struct udevd_uevent_msg *msg;
 816
 817         list_for_each_entry(msg, &running_list, node) {
 818                 if (msg->pid == pid) {
 819                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 820                              exitstatus, time(NULL) - msg->queue_time);
 821                         msg->exitstatus = exitstatus;
 822                         msg_queue_delete(msg);
 823
 824                         /* there may be events waiting with the same devpath */
 825                         run_exec_q = 1;
 826                         return;
 827                 }
 828         }
 829 }
 830
 831 static void reap_sigchilds(void)
 832 {
 833         pid_t pid;
 834         int status;
 835
 836         while (1) {
 837                 pid = waitpid(-1, &status, WNOHANG);
 838                 if (pid <= 0)
 839                         break;
 840                 if (WIFEXITED(status))
 841                         status = WEXITSTATUS(status);
 842                 else if (WIFSIGNALED(status))
 843                         status = WTERMSIG(status) + 128;
 844                 else
 845                         status = 0;
 846                 udev_done(pid, status);
 847         }
 848 }
 849
 850 static int init_udevd_socket(void)
 851 {
 852         struct sockaddr_un saddr;
 853         socklen_t addrlen;
 854         const int feature_on = 1;
 855         int retval;
 856
 857         memset(&saddr, 0x00, sizeof(saddr));
 858         saddr.sun_family = AF_LOCAL;
 859         /* use abstract namespace for socket path */
 860         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 861         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 862
 863         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 864         if (udevd_sock == -1) {
 865                 err("error getting socket: %s", strerror(errno));
 866                 return -1;
 867         }
 868
 869         /* the bind takes care of ensuring only one copy running */
 870         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 871         if (retval < 0) {
 872                 err("bind failed: %s", strerror(errno));
 873                 close(udevd_sock);
 874                 udevd_sock = -1;
 875                 return -1;
 876         }
 877
 878         /* enable receiving of the sender credentials */
 879         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 880
 881         return 0;
 882 }
 883
 884 static int init_uevent_netlink_sock(void)
 885 {
 886         struct sockaddr_nl snl;
 887         const int buffersize = 16 * 1024 * 1024;
 888         int retval;
 889
 890         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 891         snl.nl_family = AF_NETLINK;
 892         snl.nl_pid = getpid();
 893         snl.nl_groups = 1;
 894
 895         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 896         if (uevent_netlink_sock == -1) {
 897                 err("error getting socket: %s", strerror(errno));
 898                 return -1;
 899         }
 900
 901         /* set receive buffersize */
 902         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 903
 904         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 905         if (retval < 0) {
 906                 err("bind failed: %s", strerror(errno));
 907                 close(uevent_netlink_sock);
 908                 uevent_netlink_sock = -1;
 909                 return -1;
 910         }
 911         return 0;
 912 }
 913
 914 static void export_initial_seqnum(void)
 915 {
 916         char filename[PATH_SIZE];
 917         int fd;
 918         char seqnum[32];
 919         ssize_t len = 0;
 920
 921         strlcpy(filename, sysfs_path, sizeof(filename));
 922         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 923         fd = open(filename, O_RDONLY);
 924         if (fd >= 0) {
 925                 len = read(fd, seqnum, sizeof(seqnum)-1);
 926                 close(fd);
 927         }
 928         if (len <= 0) {
 929                 strcpy(seqnum, "0\n");
 930                 len = 3;
 931         }
 932         strlcpy(filename, udev_root, sizeof(filename));
 933         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 934         create_path(filename);
 935         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 936         if (fd >= 0) {
 937                 write(fd, seqnum, len);
 938                 close(fd);
 939         }
 940 }
 941
 942 int main(int argc, char *argv[], char *envp[])
 943 {
 944         int retval;
 945         int fd;
 946         struct sigaction act;
 947         fd_set readfds;
 948         const char *value;
 949         int daemonize = 0;
 950         int option;
 951         static const struct option options[] = {
 952                 { "daemon", 0, NULL, 'd' },
 953                 { "debug-trace", 0, NULL, 't' },
 954                 { "verbose", 0, NULL, 'v' },
 955                 { "help", 0, NULL, 'h' },
 956                 { "version", 0, NULL, 'V' },
 957                 {}
 958         };
 959         int rc = 1;
 960         int maxfd;
 961
 962         logging_init("udevd");
 963         udev_config_init();
 964         selinux_init();
 965         dbg("version %s", UDEV_VERSION);
 966
 967         /* parse commandline options */
 968         while (1) {
 969                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 970                 if (option == -1)
 971                         break;
 972
 973                 switch (option) {
 974                 case 'd':
 975                         daemonize = 1;
 976                         break;
 977                 case 't':
 978                         debug_trace = 1;
 979                         break;
 980                 case 'v':
 981                         verbose = 1;
 982                         if (udev_log_priority < LOG_INFO)
 983                                 udev_log_priority = LOG_INFO;
 984                         break;
 985                 case 'h':
 986                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 987                         goto exit;
 988                 case 'V':
 989                         printf("%s\n", UDEV_VERSION);
 990                         goto exit;
 991                 default:
 992                         goto exit;
 993                 }
 994         }
 995
 996         if (getuid() != 0) {
 997                 fprintf(stderr, "root privileges required\n");
 998                 err("root privileges required");
 999                 goto exit;
1000         }
1001
1002         /* make sure std{in,out,err} fd's are in a sane state */
1003         fd = open("/dev/null", O_RDWR);
1004         if (fd < 0) {
1005                 fprintf(stderr, "cannot open /dev/null\n");
1006                 err("cannot open /dev/null");
1007         }
1008         if (fd > STDIN_FILENO)
1009                 dup2(fd, STDIN_FILENO);
1010         if (write(STDOUT_FILENO, 0, 0) < 0)
1011                 dup2(fd, STDOUT_FILENO);
1012         if (write(STDERR_FILENO, 0, 0) < 0)
1013                 dup2(fd, STDERR_FILENO);
1014
1015         /* init sockets to receive events */
1016         if (init_udevd_socket() < 0) {
1017                 if (errno == EADDRINUSE) {
1018                         fprintf(stderr, "another udev daemon already running\n");
1019                         err("another udev daemon already running");
1020                         rc = 1;
1021                 } else {
1022                         fprintf(stderr, "error initializing udevd socket\n");
1023                         err("error initializing udevd socket");
1024                         rc = 2;
1025                 }
1026                 goto exit;
1027         }
1028
1029         if (init_uevent_netlink_sock() < 0) {
1030                 fprintf(stderr, "error initializing netlink socket\n");
1031                 err("error initializing netlink socket");
1032                 rc = 3;
1033                 goto exit;
1034         }
1035
1036         /* setup signal handler pipe */
1037         retval = pipe(signal_pipe);
1038         if (retval < 0) {
1039                 err("error getting pipes: %s", strerror(errno));
1040                 goto exit;
1041         }
1042
1043         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1044         if (retval < 0) {
1045                 err("error fcntl on read pipe: %s", strerror(errno));
1046                 goto exit;
1047         }
1048         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1049         if (retval < 0) {
1050                 err("error fcntl on read pipe: %s", strerror(errno));
1051                 goto exit;
1052         }
1053
1054         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1055         if (retval < 0) {
1056                 err("error fcntl on write pipe: %s", strerror(errno));
1057                 goto exit;
1058         }
1059         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1060         if (retval < 0) {
1061                 err("error fcntl on write pipe: %s", strerror(errno));
1062                 goto exit;
1063         }
1064
1065         /* parse the rules and keep them in memory */
1066         sysfs_init();
1067         udev_rules_init(&rules, 1);
1068
1069         export_initial_seqnum();
1070
1071         if (daemonize) {
1072                 pid_t pid;
1073
1074                 pid = fork();
1075                 switch (pid) {
1076                 case 0:
1077                         dbg("daemonized fork running");
1078                         break;
1079                 case -1:
1080                         err("fork of daemon failed: %s", strerror(errno));
1081                         rc = 4;
1082                         goto exit;
1083                 default:
1084                         dbg("child [%u] running, parent exits", pid);
1085                         rc = 0;
1086                         goto exit;
1087                 }
1088         }
1089
1090         /* redirect std{out,err} fd's */
1091         if (!verbose)
1092                 dup2(fd, STDOUT_FILENO);
1093         dup2(fd, STDERR_FILENO);
1094         if (fd > STDERR_FILENO)
1095                 close(fd);
1096
1097         /* set scheduling priority for the daemon */
1098         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1099
1100         chdir("/");
1101         umask(022);
1102
1103         /* become session leader */
1104         sid = setsid();
1105         dbg("our session is %d", sid);
1106
1107         /* OOM_DISABLE == -17 */
1108         fd = open("/proc/self/oom_adj", O_RDWR);
1109         if (fd < 0)
1110                 err("error disabling OOM: %s", strerror(errno));
1111         else {
1112                 write(fd, "-17", 3);
1113                 close(fd);
1114         }
1115
1116         /* set signal handlers */
1117         memset(&act, 0x00, sizeof(struct sigaction));
1118         act.sa_handler = (void (*)(int)) sig_handler;
1119         sigemptyset(&act.sa_mask);
1120         act.sa_flags = SA_RESTART;
1121         sigaction(SIGINT, &act, NULL);
1122         sigaction(SIGTERM, &act, NULL);
1123         sigaction(SIGCHLD, &act, NULL);
1124         sigaction(SIGHUP, &act, NULL);
1125
1126         /* watch rules directory */
1127         inotify_fd = inotify_init();
1128         if (inotify_fd >= 0)
1129                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1130         else if (errno == ENOSYS)
1131                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1132         else
1133                 err("inotify_init failed: %s", strerror(errno));
1134
1135         /* maximum limit of forked childs */
1136         value = getenv("UDEVD_MAX_CHILDS");
1137         if (value)
1138                 max_childs = strtoul(value, NULL, 10);
1139         else {
1140                 int memsize = mem_size_mb();
1141                 if (memsize > 0)
1142                         max_childs = 128 + (memsize / 4);
1143                 else
1144                         max_childs = UDEVD_MAX_CHILDS;
1145         }
1146         info("initialize max_childs to %u", max_childs);
1147
1148         /* start to throttle forking if maximum number of _running_ childs is reached */
1149         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1150         if (value)
1151                 max_childs_running = strtoull(value, NULL, 10);
1152         else {
1153                 int cpus = cpu_count();
1154                 if (cpus > 0)
1155                         max_childs_running = 8 + (8 * cpus);
1156                 else
1157                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1158         }
1159         info("initialize max_childs_running to %u", max_childs_running);
1160
1161         /* clear environment for forked event processes */
1162         clearenv();
1163
1164         /* export log_priority , as called programs may want to follow that setting */
1165         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1166         putenv(udev_log);
1167         if (debug_trace)
1168                 putenv("DEBUG=1");
1169
1170         maxfd = udevd_sock;
1171         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1172         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1173         maxfd = UDEV_MAX(maxfd, inotify_fd);
1174
1175         while (!udev_exit) {
1176                 struct udevd_uevent_msg *msg;
1177                 int fdcount;
1178
1179                 FD_ZERO(&readfds);
1180                 FD_SET(signal_pipe[READ_END], &readfds);
1181                 FD_SET(udevd_sock, &readfds);
1182                 FD_SET(uevent_netlink_sock, &readfds);
1183                 if (inotify_fd >= 0)
1184                         FD_SET(inotify_fd, &readfds);
1185
1186                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1187                 if (fdcount < 0) {
1188                         if (errno != EINTR)
1189                                 err("error in select: %s", strerror(errno));
1190                         continue;
1191                 }
1192
1193                 /* get control message */
1194                 if (FD_ISSET(udevd_sock, &readfds))
1195                         get_ctrl_msg();
1196
1197                 /* get netlink message */
1198                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1199                         msg = get_netlink_msg();
1200                         if (msg)
1201                                 msg_queue_insert(msg);
1202                 }
1203
1204                 /* received a signal, clear our notification pipe */
1205                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1206                         char buf[256];
1207
1208                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1209                 }
1210
1211                 /* rules directory inotify watch */
1212                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1213                         int nbytes;
1214
1215                         /* discard all possible events, we can just reload the config */
1216                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1217                                 char *buf;
1218
1219                                 reload_config = 1;
1220                                 buf = malloc(nbytes);
1221                                 if (!buf) {
1222                                         err("error getting buffer for inotify, disable watching");
1223                                         close(inotify_fd);
1224                                         inotify_fd = -1;
1225                                 }
1226                                 read(inotify_fd, buf, nbytes);
1227                                 free(buf);
1228                         }
1229                 }
1230
1231                 /* rules changed, set by inotify or a HUP signal */
1232                 if (reload_config) {
1233                         reload_config = 0;
1234                         udev_rules_cleanup(&rules);
1235                         udev_rules_init(&rules, 1);
1236                 }
1237
1238                 /* forked child has returned */
1239                 if (sigchilds_waiting) {
1240                         sigchilds_waiting = 0;
1241                         reap_sigchilds();
1242                 }
1243
1244                 if (run_exec_q) {
1245                         run_exec_q = 0;
1246                         if (!stop_exec_q)
1247                                 msg_queue_manager();
1248                 }
1249         }
1250         rc = 0;
1251
1252 exit:
1253         udev_rules_cleanup(&rules);
1254         sysfs_cleanup();
1255         selinux_exit();
1256
1257         if (signal_pipe[READ_END] >= 0)
1258                 close(signal_pipe[READ_END]);
1259         if (signal_pipe[WRITE_END] >= 0)
1260                 close(signal_pipe[WRITE_END]);
1261
1262         if (udevd_sock >= 0)
1263                 close(udevd_sock);
1264         if (inotify_fd >= 0)
1265                 close(inotify_fd);
1266         if (uevent_netlink_sock >= 0)
1267                 close(uevent_netlink_sock);
1268
1269         logging_close();
1270
1271         return rc;
1272 }