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         if (verbose) {
  81                 printf("[%d] ", (int) getpid());
  82                 vprintf(format, args);
  83                 printf("\n");
  84         } else
  85                 vsyslog(priority, format, args);
  86         va_end(args);
  87 }
  88
  89 #endif
  90
  91 static void asmlinkage udev_event_sig_handler(int signum)
  92 {
  93         if (signum == SIGALRM)
  94                 exit(1);
  95 }
  96
  97 static int udev_event_process(struct udevd_uevent_msg *msg)
  98 {
  99         struct sigaction act;
 100         struct udevice *udev;
 101         int i;
 102         int retval;
 103
 104         /* set signal handlers */
 105         memset(&act, 0x00, sizeof(act));
 106         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 107         sigemptyset (&act.sa_mask);
 108         act.sa_flags = 0;
 109         sigaction(SIGALRM, &act, NULL);
 110
 111         /* reset to default */
 112         act.sa_handler = SIG_DFL;
 113         sigaction(SIGINT, &act, NULL);
 114         sigaction(SIGTERM, &act, NULL);
 115         sigaction(SIGCHLD, &act, NULL);
 116         sigaction(SIGHUP, &act, NULL);
 117
 118         /* trigger timeout to prevent hanging processes */
 119         alarm(UDEV_ALARM_TIMEOUT);
 120
 121         /* reconstruct event environment from message */
 122         for (i = 0; msg->envp[i]; i++)
 123                 putenv(msg->envp[i]);
 124
 125         udev = udev_device_init(NULL);
 126         if (udev == NULL)
 127                 return -1;
 128         strlcpy(udev->action, msg->action, sizeof(udev->action));
 129         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 130         udev->devpath_old = msg->devpath_old;
 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                 retval = udev_rules_run(udev);
 138
 139         udev_device_cleanup(udev);
 140         return retval;
 141 }
 142
 143 enum event_state {
 144         EVENT_QUEUED,
 145         EVENT_FINISHED,
 146         EVENT_FAILED,
 147 };
 148
 149 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 150 {
 151         char filename[PATH_SIZE];
 152         char filename_failed[PATH_SIZE];
 153         size_t start;
 154
 155         /* location of queue file */
 156         snprintf(filename, sizeof(filename), "%s/"EVENT_QUEUE_DIR"/%llu", udev_root, msg->seqnum);
 157
 158         /* location of failed file */
 159         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 160         strlcat(filename_failed, "/", sizeof(filename_failed));
 161         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 162         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 163         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 164
 165         switch (state) {
 166         case EVENT_QUEUED:
 167                 unlink(filename_failed);
 168                 delete_path(filename_failed);
 169
 170                 create_path(filename);
 171                 selinux_setfscreatecon(filename, NULL, S_IFLNK);
 172                 symlink(msg->devpath, filename);
 173                 selinux_resetfscreatecon();
 174                 break;
 175         case EVENT_FINISHED:
 176                 if (msg->devpath_old != NULL) {
 177                         /* "move" event - rename failed file to current name, do not delete failed */
 178                         char filename_failed_old[PATH_SIZE];
 179
 180                         strlcpy(filename_failed_old, udev_root, sizeof(filename_failed_old));
 181                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 182                         start = strlcat(filename_failed_old, EVENT_FAILED_DIR"/", sizeof(filename_failed_old));
 183                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 184                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 185
 186                         if (rename(filename_failed_old, filename_failed) == 0)
 187                                 info("renamed devpath, moved failed state of '%s' to %s'",
 188                                      msg->devpath_old, msg->devpath);
 189                 } else {
 190                         unlink(filename_failed);
 191                         delete_path(filename_failed);
 192                 }
 193
 194                 unlink(filename);
 195                 delete_path(filename);
 196                 break;
 197         case EVENT_FAILED:
 198                 /* move failed event to the failed directory */
 199                 create_path(filename_failed);
 200                 rename(filename, filename_failed);
 201
 202                 /* clean up possibly empty queue directory */
 203                 delete_path(filename);
 204                 break;
 205         }
 206
 207         return;
 208 }
 209
 210 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 211 {
 212         list_del(&msg->node);
 213
 214         /* mark as failed, if "add" event returns non-zero */
 215         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 216                 export_event_state(msg, EVENT_FAILED);
 217         else
 218                 export_event_state(msg, EVENT_FINISHED);
 219
 220         free(msg);
 221 }
 222
 223 static void udev_event_run(struct udevd_uevent_msg *msg)
 224 {
 225         pid_t pid;
 226         int retval;
 227
 228         pid = fork();
 229         switch (pid) {
 230         case 0:
 231                 /* child */
 232                 close(uevent_netlink_sock);
 233                 close(udevd_sock);
 234                 if (inotify_fd >= 0)
 235                         close(inotify_fd);
 236                 close(signal_pipe[READ_END]);
 237                 close(signal_pipe[WRITE_END]);
 238                 logging_close();
 239
 240                 logging_init("udevd-event");
 241                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 242
 243                 retval = udev_event_process(msg);
 244                 info("seq %llu finished with %i", msg->seqnum, retval);
 245
 246                 logging_close();
 247                 if (retval)
 248                         exit(1);
 249                 exit(0);
 250         case -1:
 251                 err("fork of child failed: %s", strerror(errno));
 252                 msg_queue_delete(msg);
 253                 break;
 254         default:
 255                 /* get SIGCHLD in main loop */
 256                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 257                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 258                 msg->pid = pid;
 259         }
 260 }
 261
 262 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 263 {
 264         char filename[PATH_SIZE];
 265         int fd;
 266
 267         msg->queue_time = time(NULL);
 268
 269         strlcpy(filename, udev_root, sizeof(filename));
 270         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 271         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 272         if (fd >= 0) {
 273                 char str[32];
 274                 int len;
 275
 276                 len = sprintf(str, "%llu\n", msg->seqnum);
 277                 write(fd, str, len);
 278                 close(fd);
 279         }
 280
 281         export_event_state(msg, EVENT_QUEUED);
 282         info("seq %llu queued, '%s' '%s'", msg->seqnum, msg->action, msg->subsystem);
 283
 284         /* run one event after the other in debug mode */
 285         if (debug_trace) {
 286                 list_add_tail(&msg->node, &running_list);
 287                 udev_event_run(msg);
 288                 waitpid(msg->pid, NULL, 0);
 289                 msg_queue_delete(msg);
 290                 return;
 291         }
 292
 293         /* run all events with a timeout set immediately */
 294         if (msg->timeout != 0) {
 295                 list_add_tail(&msg->node, &running_list);
 296                 udev_event_run(msg);
 297                 return;
 298         }
 299
 300         list_add_tail(&msg->node, &exec_list);
 301         run_exec_q = 1;
 302 }
 303
 304 static int mem_size_mb(void)
 305 {
 306         FILE* f;
 307         char buf[4096];
 308         long int memsize = -1;
 309
 310         f = fopen("/proc/meminfo", "r");
 311         if (f == NULL)
 312                 return -1;
 313
 314         while (fgets(buf, sizeof(buf), f) != NULL) {
 315                 long int value;
 316
 317                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 318                         memsize = value / 1024;
 319                         break;
 320                 }
 321         }
 322
 323         fclose(f);
 324         return memsize;
 325 }
 326
 327 static int cpu_count(void)
 328 {
 329         FILE* f;
 330         char buf[4096];
 331         int count = 0;
 332
 333         f = fopen("/proc/stat", "r");
 334         if (f == NULL)
 335                 return -1;
 336
 337         while (fgets(buf, sizeof(buf), f) != NULL) {
 338                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 339                         count++;
 340         }
 341
 342         fclose(f);
 343         if (count == 0)
 344                 return -1;
 345         return count;
 346 }
 347
 348 static int running_processes(void)
 349 {
 350         FILE* f;
 351         char buf[4096];
 352         int running = -1;
 353
 354         f = fopen("/proc/stat", "r");
 355         if (f == NULL)
 356                 return -1;
 357
 358         while (fgets(buf, sizeof(buf), f) != NULL) {
 359                 int value;
 360
 361                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 362                         running = value;
 363                         break;
 364                 }
 365         }
 366
 367         fclose(f);
 368         return running;
 369 }
 370
 371 /* return the number of process es in our session, count only until limit */
 372 static int running_processes_in_session(pid_t session, int limit)
 373 {
 374         DIR *dir;
 375         struct dirent *dent;
 376         int running = 0;
 377
 378         dir = opendir("/proc");
 379         if (!dir)
 380                 return -1;
 381
 382         /* read process info from /proc */
 383         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 384                 int f;
 385                 char procdir[64];
 386                 char line[256];
 387                 const char *pos;
 388                 char state;
 389                 pid_t ppid, pgrp, sess;
 390                 int len;
 391
 392                 if (!isdigit(dent->d_name[0]))
 393                         continue;
 394
 395                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 396                 procdir[sizeof(procdir)-1] = '\0';
 397
 398                 f = open(procdir, O_RDONLY);
 399                 if (f == -1)
 400                         continue;
 401
 402                 len = read(f, line, sizeof(line)-1);
 403                 close(f);
 404
 405                 if (len <= 0)
 406                         continue;
 407                 else
 408                         line[len] = '\0';
 409
 410                 /* skip ugly program name */
 411                 pos = strrchr(line, ')') + 2;
 412                 if (pos == NULL)
 413                         continue;
 414
 415                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 416                         continue;
 417
 418                 /* count only processes in our session */
 419                 if (sess != session)
 420                         continue;
 421
 422                 /* count only running, no sleeping processes */
 423                 if (state != 'R')
 424                         continue;
 425
 426                 running++;
 427                 if (limit > 0 && running >= limit)
 428                         break;
 429         }
 430         closedir(dir);
 431
 432         return running;
 433 }
 434
 435 static int compare_devpath(const char *running, const char *waiting)
 436 {
 437         int i;
 438
 439         for (i = 0; i < PATH_SIZE; i++) {
 440                 /* identical device event found */
 441                 if (running[i] == '\0' && waiting[i] == '\0')
 442                         return 1;
 443
 444                 /* parent device event found */
 445                 if (running[i] == '\0' && waiting[i] == '/')
 446                         return 2;
 447
 448                 /* child device event found */
 449                 if (running[i] == '/' && waiting[i] == '\0')
 450                         return 3;
 451
 452                 /* no matching event */
 453                 if (running[i] != waiting[i])
 454                         break;
 455         }
 456
 457         return 0;
 458 }
 459
 460 /* lookup event for identical, parent, child, or physical device */
 461 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 462 {
 463         struct udevd_uevent_msg *loop_msg;
 464         int childs_count = 0;
 465
 466         /* check exec-queue which may still contain delayed events we depend on */
 467         list_for_each_entry(loop_msg, &exec_list, node) {
 468                 /* skip ourself and all later events */
 469                 if (loop_msg->seqnum >= msg->seqnum)
 470                         break;
 471
 472                 /* check our old name */
 473                 if (msg->devpath_old != NULL)
 474                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 475                                 return 2;
 476
 477                 /* check identical, parent, or child device event */
 478                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 479                         dbg("%llu, device event still pending %llu (%s)",
 480                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 481                         return 3;
 482                 }
 483
 484                 /* check for our major:minor number */
 485                 if (msg->devt && loop_msg->devt == msg->devt &&
 486                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 487                         dbg("%llu, device event still pending %llu (%d:%d)", msg->seqnum,
 488                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 489                         return 4;
 490                 }
 491
 492                 /* check physical device event (special case of parent) */
 493                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 494                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 495                                 dbg("%llu, physical device event still pending %llu (%s)",
 496                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 497                                 return 5;
 498                         }
 499         }
 500
 501         /* check run queue for still running events */
 502         list_for_each_entry(loop_msg, &running_list, node) {
 503                 if (limit && childs_count++ > limit) {
 504                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 505                         return 1;
 506                 }
 507
 508                 /* check our old name */
 509                 if (msg->devpath_old != NULL)
 510                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 511                                 return 2;
 512
 513                 /* check identical, parent, or child device event */
 514                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 515                         dbg("%llu, device event still running %llu (%s)",
 516                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 517                         return 3;
 518                 }
 519
 520                 /* check for our major:minor number */
 521                 if (msg->devt && loop_msg->devt == msg->devt &&
 522                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 523                         dbg("%llu, device event still running %llu (%d:%d)", msg->seqnum,
 524                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 525                         return 4;
 526                 }
 527
 528                 /* check physical device event (special case of parent) */
 529                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 530                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 531                                 dbg("%llu, physical device event still running %llu (%s)",
 532                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 533                                 return 5;
 534                         }
 535         }
 536         return 0;
 537 }
 538
 539 /* serializes events for the identical and parent and child devices */
 540 static void msg_queue_manager(void)
 541 {
 542         struct udevd_uevent_msg *loop_msg;
 543         struct udevd_uevent_msg *tmp_msg;
 544         int running;
 545
 546         if (list_empty(&exec_list))
 547                 return;
 548
 549         running = running_processes();
 550         dbg("%d processes runnning on system", running);
 551         if (running < 0)
 552                 running = max_childs_running;
 553
 554         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 555                 /* check running processes in our session and possibly throttle */
 556                 if (running >= max_childs_running) {
 557                         running = running_processes_in_session(sid, max_childs_running+10);
 558                         dbg("at least %d processes running in session", running);
 559                         if (running >= max_childs_running) {
 560                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 561                                 return;
 562                         }
 563                 }
 564
 565                 /* serialize and wait for parent or child events */
 566                 if (devpath_busy(loop_msg, max_childs) != 0) {
 567                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 568                         continue;
 569                 }
 570
 571                 /* move event to run list */
 572                 list_move_tail(&loop_msg->node, &running_list);
 573                 udev_event_run(loop_msg);
 574                 running++;
 575                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 576         }
 577 }
 578
 579 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 580 {
 581         int bufpos;
 582         int i;
 583         struct udevd_uevent_msg *msg;
 584         char *physdevdriver_key = NULL;
 585         int maj = 0;
 586         int min = 0;
 587
 588         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 589         if (msg == NULL)
 590                 return NULL;
 591         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 592
 593         /* copy environment buffer and reconstruct envp */
 594         memcpy(msg->envbuf, buf, buf_size);
 595         bufpos = 0;
 596         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 597                 int keylen;
 598                 char *key;
 599
 600                 key = &msg->envbuf[bufpos];
 601                 keylen = strlen(key);
 602                 msg->envp[i] = key;
 603                 bufpos += keylen + 1;
 604                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 605
 606                 /* remember some keys for further processing */
 607                 if (strncmp(key, "ACTION=", 7) == 0)
 608                         msg->action = &key[7];
 609                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 610                         msg->devpath = &key[8];
 611                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 612                         msg->subsystem = &key[10];
 613                 else if (strncmp(key, "DRIVER=", 7) == 0)
 614                         msg->driver = &key[7];
 615                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 616                         msg->seqnum = strtoull(&key[7], NULL, 10);
 617                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 618                         msg->devpath_old = &key[12];
 619                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 620                         msg->physdevpath = &key[12];
 621                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 622                         physdevdriver_key = key;
 623                 else if (strncmp(key, "MAJOR=", 6) == 0)
 624                         maj = strtoull(&key[6], NULL, 10);
 625                 else if (strncmp(key, "MINOR=", 6) == 0)
 626                         min = strtoull(&key[6], NULL, 10);
 627                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 628                         msg->timeout = strtoull(&key[8], NULL, 10);
 629         }
 630         msg->devt = makedev(maj, min);
 631         msg->envp[i++] = "UDEVD_EVENT=1";
 632
 633         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 634                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 635                 msg->envp[i++] = &physdevdriver_key[7];
 636                 msg->driver = &physdevdriver_key[14];
 637         }
 638
 639         msg->envp[i] = NULL;
 640
 641         if (msg->devpath == NULL || msg->action == NULL) {
 642                 info("DEVPATH or ACTION missing, ignore message");
 643                 free(msg);
 644                 return NULL;
 645         }
 646         return msg;
 647 }
 648
 649 /* receive the udevd message from userspace */
 650 static void get_ctrl_msg(void)
 651 {
 652         struct udevd_ctrl_msg ctrl_msg;
 653         ssize_t size;
 654         struct msghdr smsg;
 655         struct cmsghdr *cmsg;
 656         struct iovec iov;
 657         struct ucred *cred;
 658         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 659         int *intval;
 660         char *pos;
 661
 662         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 663         iov.iov_base = &ctrl_msg;
 664         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 665
 666         memset(&smsg, 0x00, sizeof(struct msghdr));
 667         smsg.msg_iov = &iov;
 668         smsg.msg_iovlen = 1;
 669         smsg.msg_control = cred_msg;
 670         smsg.msg_controllen = sizeof(cred_msg);
 671
 672         size = recvmsg(udevd_sock, &smsg, 0);
 673         if (size <  0) {
 674                 if (errno != EINTR)
 675                         err("unable to receive user udevd message: %s", strerror(errno));
 676                 return;
 677         }
 678         cmsg = CMSG_FIRSTHDR(&smsg);
 679         cred = (struct ucred *) CMSG_DATA(cmsg);
 680
 681         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 682                 err("no sender credentials received, message ignored");
 683                 return;
 684         }
 685
 686         if (cred->uid != 0) {
 687                 err("sender uid=%i, message ignored", cred->uid);
 688                 return;
 689         }
 690
 691         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 692                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 693                 return;
 694         }
 695
 696         switch (ctrl_msg.type) {
 697         case UDEVD_CTRL_ENV:
 698                 pos = strchr(ctrl_msg.buf, '=');
 699                 if (pos == NULL) {
 700                         err("wrong key format '%s'", ctrl_msg.buf);
 701                         break;
 702                 }
 703                 pos[0] = '\0';
 704                 if (pos[1] == '\0') {
 705                         info("udevd message (ENV) received, unset '%s'", ctrl_msg.buf);
 706                         unsetenv(ctrl_msg.buf);
 707                 } else {
 708                         info("udevd message (ENV) received, set '%s=%s'", ctrl_msg.buf, &pos[1]);
 709                         setenv(ctrl_msg.buf, &pos[1], 1);
 710                 }
 711                 break;
 712         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 713                 info("udevd message (STOP_EXEC_QUEUE) received");
 714                 stop_exec_q = 1;
 715                 break;
 716         case UDEVD_CTRL_START_EXEC_QUEUE:
 717                 info("udevd message (START_EXEC_QUEUE) received");
 718                 stop_exec_q = 0;
 719                 msg_queue_manager();
 720                 break;
 721         case UDEVD_CTRL_SET_LOG_LEVEL:
 722                 intval = (int *) ctrl_msg.buf;
 723                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 724                 udev_log_priority = *intval;
 725                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 726                 putenv(udev_log);
 727                 break;
 728         case UDEVD_CTRL_SET_MAX_CHILDS:
 729                 intval = (int *) ctrl_msg.buf;
 730                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 731                 max_childs = *intval;
 732                 break;
 733         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 734                 intval = (int *) ctrl_msg.buf;
 735                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 736                 max_childs_running = *intval;
 737                 break;
 738         case UDEVD_CTRL_RELOAD_RULES:
 739                 info("udevd message (RELOAD_RULES) received");
 740                 reload_config = 1;
 741                 break;
 742         default:
 743                 err("unknown control message type");
 744         }
 745 }
 746
 747 /* receive the kernel user event message and do some sanity checks */
 748 static struct udevd_uevent_msg *get_netlink_msg(void)
 749 {
 750         struct udevd_uevent_msg *msg;
 751         int bufpos;
 752         ssize_t size;
 753         static char buffer[UEVENT_BUFFER_SIZE+512];
 754         char *pos;
 755
 756         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 757         if (size <  0) {
 758                 if (errno != EINTR)
 759                         err("unable to receive kernel netlink message: %s", strerror(errno));
 760                 return NULL;
 761         }
 762
 763         if ((size_t)size > sizeof(buffer)-1)
 764                 size = sizeof(buffer)-1;
 765         buffer[size] = '\0';
 766         dbg("uevent_size=%zi", size);
 767
 768         /* start of event payload */
 769         bufpos = strlen(buffer)+1;
 770         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 771         if (msg == NULL)
 772                 return NULL;
 773
 774         /* validate message */
 775         pos = strchr(buffer, '@');
 776         if (pos == NULL) {
 777                 err("invalid uevent '%s'", buffer);
 778                 free(msg);
 779                 return NULL;
 780         }
 781         pos[0] = '\0';
 782
 783         if (msg->action == NULL) {
 784                 info("no ACTION in payload found, skip event '%s'", buffer);
 785                 free(msg);
 786                 return NULL;
 787         }
 788
 789         if (strcmp(msg->action, buffer) != 0) {
 790                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 791                 free(msg);
 792                 return NULL;
 793         }
 794
 795         return msg;
 796 }
 797
 798 static void asmlinkage sig_handler(int signum)
 799 {
 800         switch (signum) {
 801                 case SIGINT:
 802                 case SIGTERM:
 803                         udev_exit = 1;
 804                         break;
 805                 case SIGCHLD:
 806                         /* set flag, then write to pipe if needed */
 807                         sigchilds_waiting = 1;
 808                         break;
 809                 case SIGHUP:
 810                         reload_config = 1;
 811                         break;
 812         }
 813
 814         /* write to pipe, which will wakeup select() in our mainloop */
 815         write(signal_pipe[WRITE_END], "", 1);
 816 }
 817
 818 static void udev_done(int pid, int exitstatus)
 819 {
 820         /* find msg associated with pid and delete it */
 821         struct udevd_uevent_msg *msg;
 822
 823         list_for_each_entry(msg, &running_list, node) {
 824                 if (msg->pid == pid) {
 825                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 826                              exitstatus, time(NULL) - msg->queue_time);
 827                         msg->exitstatus = exitstatus;
 828                         msg_queue_delete(msg);
 829
 830                         /* there may be events waiting with the same devpath */
 831                         run_exec_q = 1;
 832                         return;
 833                 }
 834         }
 835 }
 836
 837 static void reap_sigchilds(void)
 838 {
 839         pid_t pid;
 840         int status;
 841
 842         while (1) {
 843                 pid = waitpid(-1, &status, WNOHANG);
 844                 if (pid <= 0)
 845                         break;
 846                 if (WIFEXITED(status))
 847                         status = WEXITSTATUS(status);
 848                 else if (WIFSIGNALED(status))
 849                         status = WTERMSIG(status) + 128;
 850                 else
 851                         status = 0;
 852                 udev_done(pid, status);
 853         }
 854 }
 855
 856 static int init_udevd_socket(void)
 857 {
 858         struct sockaddr_un saddr;
 859         socklen_t addrlen;
 860         const int feature_on = 1;
 861         int retval;
 862
 863         memset(&saddr, 0x00, sizeof(saddr));
 864         saddr.sun_family = AF_LOCAL;
 865         /* use abstract namespace for socket path */
 866         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 867         addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(&saddr.sun_path[1]);
 868
 869         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 870         if (udevd_sock == -1) {
 871                 err("error getting socket: %s", strerror(errno));
 872                 return -1;
 873         }
 874
 875         /* the bind takes care of ensuring only one copy running */
 876         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 877         if (retval < 0) {
 878                 err("bind failed: %s", strerror(errno));
 879                 close(udevd_sock);
 880                 udevd_sock = -1;
 881                 return -1;
 882         }
 883
 884         /* enable receiving of the sender credentials */
 885         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 886
 887         return 0;
 888 }
 889
 890 static int init_uevent_netlink_sock(void)
 891 {
 892         struct sockaddr_nl snl;
 893         const int buffersize = 16 * 1024 * 1024;
 894         int retval;
 895
 896         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 897         snl.nl_family = AF_NETLINK;
 898         snl.nl_pid = getpid();
 899         snl.nl_groups = 1;
 900
 901         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 902         if (uevent_netlink_sock == -1) {
 903                 err("error getting socket: %s", strerror(errno));
 904                 return -1;
 905         }
 906
 907         /* set receive buffersize */
 908         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 909
 910         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 911         if (retval < 0) {
 912                 err("bind failed: %s", strerror(errno));
 913                 close(uevent_netlink_sock);
 914                 uevent_netlink_sock = -1;
 915                 return -1;
 916         }
 917         return 0;
 918 }
 919
 920 static void export_initial_seqnum(void)
 921 {
 922         char filename[PATH_SIZE];
 923         int fd;
 924         char seqnum[32];
 925         ssize_t len = 0;
 926
 927         strlcpy(filename, sysfs_path, sizeof(filename));
 928         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 929         fd = open(filename, O_RDONLY);
 930         if (fd >= 0) {
 931                 len = read(fd, seqnum, sizeof(seqnum)-1);
 932                 close(fd);
 933         }
 934         if (len <= 0) {
 935                 strcpy(seqnum, "0\n");
 936                 len = 3;
 937         }
 938         strlcpy(filename, udev_root, sizeof(filename));
 939         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 940         create_path(filename);
 941         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 942         if (fd >= 0) {
 943                 write(fd, seqnum, len);
 944                 close(fd);
 945         }
 946 }
 947
 948 int main(int argc, char *argv[], char *envp[])
 949 {
 950         int retval;
 951         int fd;
 952         struct sigaction act;
 953         fd_set readfds;
 954         const char *value;
 955         int daemonize = 0;
 956         int option;
 957         static const struct option options[] = {
 958                 { "daemon", 0, NULL, 'd' },
 959                 { "debug-trace", 0, NULL, 't' },
 960                 { "verbose", 0, NULL, 'v' },
 961                 { "help", 0, NULL, 'h' },
 962                 { "version", 0, NULL, 'V' },
 963                 {}
 964         };
 965         int rc = 1;
 966         int maxfd;
 967
 968         logging_init("udevd");
 969         udev_config_init();
 970         selinux_init();
 971         dbg("version %s", UDEV_VERSION);
 972
 973         while (1) {
 974                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 975                 if (option == -1)
 976                         break;
 977
 978                 switch (option) {
 979                 case 'd':
 980                         daemonize = 1;
 981                         break;
 982                 case 't':
 983                         debug_trace = 1;
 984                         break;
 985                 case 'v':
 986                         verbose = 1;
 987                         if (udev_log_priority < LOG_INFO)
 988                                 udev_log_priority = LOG_INFO;
 989                         break;
 990                 case 'h':
 991                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 992                         goto exit;
 993                 case 'V':
 994                         printf("%s\n", UDEV_VERSION);
 995                         goto exit;
 996                 default:
 997                         goto exit;
 998                 }
 999         }
1000
1001         if (getuid() != 0) {
1002                 fprintf(stderr, "root privileges required\n");
1003                 err("root privileges required");
1004                 goto exit;
1005         }
1006
1007         /* make sure std{in,out,err} fd's are in a sane state */
1008         fd = open("/dev/null", O_RDWR);
1009         if (fd < 0) {
1010                 fprintf(stderr, "cannot open /dev/null\n");
1011                 err("cannot open /dev/null");
1012         }
1013         if (fd > STDIN_FILENO)
1014                 dup2(fd, STDIN_FILENO);
1015         if (write(STDOUT_FILENO, 0, 0) < 0)
1016                 dup2(fd, STDOUT_FILENO);
1017         if (write(STDERR_FILENO, 0, 0) < 0)
1018                 dup2(fd, STDERR_FILENO);
1019
1020         /* init sockets to receive events */
1021         if (init_udevd_socket() < 0) {
1022                 if (errno == EADDRINUSE) {
1023                         fprintf(stderr, "another udev daemon already running\n");
1024                         err("another udev daemon already running");
1025                         rc = 1;
1026                 } else {
1027                         fprintf(stderr, "error initializing udevd socket\n");
1028                         err("error initializing udevd socket");
1029                         rc = 2;
1030                 }
1031                 goto exit;
1032         }
1033
1034         if (init_uevent_netlink_sock() < 0) {
1035                 fprintf(stderr, "error initializing netlink socket\n");
1036                 err("error initializing netlink socket");
1037                 rc = 3;
1038                 goto exit;
1039         }
1040
1041         /* setup signal handler pipe */
1042         retval = pipe(signal_pipe);
1043         if (retval < 0) {
1044                 err("error getting pipes: %s", strerror(errno));
1045                 goto exit;
1046         }
1047
1048         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1049         if (retval < 0) {
1050                 err("error fcntl on read pipe: %s", strerror(errno));
1051                 goto exit;
1052         }
1053         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1054         if (retval < 0) {
1055                 err("error fcntl on read pipe: %s", strerror(errno));
1056                 goto exit;
1057         }
1058
1059         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1060         if (retval < 0) {
1061                 err("error fcntl on write pipe: %s", strerror(errno));
1062                 goto exit;
1063         }
1064         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1065         if (retval < 0) {
1066                 err("error fcntl on write pipe: %s", strerror(errno));
1067                 goto exit;
1068         }
1069
1070         /* parse the rules and keep them in memory */
1071         sysfs_init();
1072         udev_rules_init(&rules, 1);
1073
1074         export_initial_seqnum();
1075
1076         if (daemonize) {
1077                 pid_t pid;
1078
1079                 pid = fork();
1080                 switch (pid) {
1081                 case 0:
1082                         dbg("daemonized fork running");
1083                         break;
1084                 case -1:
1085                         err("fork of daemon failed: %s", strerror(errno));
1086                         rc = 4;
1087                         goto exit;
1088                 default:
1089                         dbg("child [%u] running, parent exits", pid);
1090                         rc = 0;
1091                         goto exit;
1092                 }
1093         }
1094
1095         /* redirect std{out,err} fd's */
1096         if (!verbose)
1097                 dup2(fd, STDOUT_FILENO);
1098         dup2(fd, STDERR_FILENO);
1099         if (fd > STDERR_FILENO)
1100                 close(fd);
1101
1102         /* set scheduling priority for the daemon */
1103         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1104
1105         chdir("/");
1106         umask(022);
1107
1108         /* become session leader */
1109         sid = setsid();
1110         dbg("our session is %d", sid);
1111
1112         /* OOM_DISABLE == -17 */
1113         fd = open("/proc/self/oom_adj", O_RDWR);
1114         if (fd < 0)
1115                 err("error disabling OOM: %s", strerror(errno));
1116         else {
1117                 write(fd, "-17", 3);
1118                 close(fd);
1119         }
1120
1121         fd = open("/dev/kmsg", O_WRONLY);
1122         if (fd > 0) {
1123                 const char *str = "<6>udevd version " UDEV_VERSION " started\n";
1124
1125                 write(fd, str, strlen(str));
1126                 close(fd);
1127         }
1128
1129         /* set signal handlers */
1130         memset(&act, 0x00, sizeof(struct sigaction));
1131         act.sa_handler = (void (*)(int)) sig_handler;
1132         sigemptyset(&act.sa_mask);
1133         act.sa_flags = SA_RESTART;
1134         sigaction(SIGINT, &act, NULL);
1135         sigaction(SIGTERM, &act, NULL);
1136         sigaction(SIGCHLD, &act, NULL);
1137         sigaction(SIGHUP, &act, NULL);
1138
1139         /* watch rules directory */
1140         inotify_fd = inotify_init();
1141         if (inotify_fd >= 0) {
1142                 char filename[PATH_MAX];
1143
1144                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1145
1146                 /* watch dynamic rules directory */
1147                 strlcpy(filename, udev_root, sizeof(filename));
1148                 strlcat(filename, "/"RULES_DYN_DIR, sizeof(filename));
1149                 inotify_add_watch(inotify_fd, filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1150         } else if (errno == ENOSYS)
1151                 err("the kernel does not support inotify, udevd can't monitor rules file changes");
1152         else
1153                 err("inotify_init failed: %s", strerror(errno));
1154
1155         /* maximum limit of forked childs */
1156         value = getenv("UDEVD_MAX_CHILDS");
1157         if (value)
1158                 max_childs = strtoul(value, NULL, 10);
1159         else {
1160                 int memsize = mem_size_mb();
1161                 if (memsize > 0)
1162                         max_childs = 128 + (memsize / 4);
1163                 else
1164                         max_childs = UDEVD_MAX_CHILDS;
1165         }
1166         info("initialize max_childs to %u", max_childs);
1167
1168         /* start to throttle forking if maximum number of _running_ childs is reached */
1169         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1170         if (value)
1171                 max_childs_running = strtoull(value, NULL, 10);
1172         else {
1173                 int cpus = cpu_count();
1174                 if (cpus > 0)
1175                         max_childs_running = 8 + (8 * cpus);
1176                 else
1177                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1178         }
1179         info("initialize max_childs_running to %u", max_childs_running);
1180
1181         /* clear environment for forked event processes */
1182         clearenv();
1183
1184         /* export log_priority , as called programs may want to follow that setting */
1185         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1186         putenv(udev_log);
1187         if (debug_trace)
1188                 putenv("DEBUG=1");
1189
1190         maxfd = udevd_sock;
1191         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1192         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1193         maxfd = UDEV_MAX(maxfd, inotify_fd);
1194
1195         while (!udev_exit) {
1196                 struct udevd_uevent_msg *msg;
1197                 int fdcount;
1198
1199                 FD_ZERO(&readfds);
1200                 FD_SET(signal_pipe[READ_END], &readfds);
1201                 FD_SET(udevd_sock, &readfds);
1202                 FD_SET(uevent_netlink_sock, &readfds);
1203                 if (inotify_fd >= 0)
1204                         FD_SET(inotify_fd, &readfds);
1205
1206                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1207                 if (fdcount < 0) {
1208                         if (errno != EINTR)
1209                                 err("error in select: %s", strerror(errno));
1210                         continue;
1211                 }
1212
1213                 /* get control message */
1214                 if (FD_ISSET(udevd_sock, &readfds))
1215                         get_ctrl_msg();
1216
1217                 /* get netlink message */
1218                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1219                         msg = get_netlink_msg();
1220                         if (msg)
1221                                 msg_queue_insert(msg);
1222                 }
1223
1224                 /* received a signal, clear our notification pipe */
1225                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1226                         char buf[256];
1227
1228                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1229                 }
1230
1231                 /* rules directory inotify watch */
1232                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1233                         int nbytes;
1234
1235                         /* discard all possible events, we can just reload the config */
1236                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1237                                 char *buf;
1238
1239                                 reload_config = 1;
1240                                 buf = malloc(nbytes);
1241                                 if (buf == NULL) {
1242                                         err("error getting buffer for inotify, disable watching");
1243                                         close(inotify_fd);
1244                                         inotify_fd = -1;
1245                                 }
1246                                 read(inotify_fd, buf, nbytes);
1247                                 free(buf);
1248                         }
1249                 }
1250
1251                 /* rules changed, set by inotify or a HUP signal */
1252                 if (reload_config) {
1253                         reload_config = 0;
1254                         udev_rules_cleanup(&rules);
1255                         udev_rules_init(&rules, 1);
1256                 }
1257
1258                 /* forked child has returned */
1259                 if (sigchilds_waiting) {
1260                         sigchilds_waiting = 0;
1261                         reap_sigchilds();
1262                 }
1263
1264                 if (run_exec_q) {
1265                         run_exec_q = 0;
1266                         if (!stop_exec_q)
1267                                 msg_queue_manager();
1268                 }
1269         }
1270         rc = 0;
1271
1272 exit:
1273         udev_rules_cleanup(&rules);
1274         sysfs_cleanup();
1275         selinux_exit();
1276
1277         if (signal_pipe[READ_END] >= 0)
1278                 close(signal_pipe[READ_END]);
1279         if (signal_pipe[WRITE_END] >= 0)
1280                 close(signal_pipe[WRITE_END]);
1281
1282         if (udevd_sock >= 0)
1283                 close(udevd_sock);
1284         if (inotify_fd >= 0)
1285                 close(inotify_fd);
1286         if (uevent_netlink_sock >= 0)
1287                 close(uevent_netlink_sock);
1288
1289         logging_close();
1290
1291         return rc;
1292 }