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         if (verbose) {
  80                 printf("[%d] ", (int) getpid());
  81                 va_start(args, format);
  82                 vprintf(format, args);
  83                 va_end(args);
  84                 printf("\n");
  85         } else {
  86                 va_start(args, format);
  87                 vsyslog(priority, format, args);
  88                 va_end(args);
  89         }
  90 }
  91
  92 #endif
  93
  94 static void asmlinkage udev_event_sig_handler(int signum)
  95 {
  96         if (signum == SIGALRM)
  97                 exit(1);
  98 }
  99
 100 static int udev_event_process(struct udevd_uevent_msg *msg)
 101 {
 102         struct sigaction act;
 103         struct udevice *udev;
 104         int i;
 105         int retval;
 106
 107         /* set signal handlers */
 108         memset(&act, 0x00, sizeof(act));
 109         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 110         sigemptyset (&act.sa_mask);
 111         act.sa_flags = 0;
 112         sigaction(SIGALRM, &act, NULL);
 113
 114         /* reset to default */
 115         act.sa_handler = SIG_DFL;
 116         sigaction(SIGINT, &act, NULL);
 117         sigaction(SIGTERM, &act, NULL);
 118         sigaction(SIGCHLD, &act, NULL);
 119         sigaction(SIGHUP, &act, NULL);
 120
 121         /* trigger timeout to prevent hanging processes */
 122         alarm(UDEV_ALARM_TIMEOUT);
 123
 124         /* reconstruct event environment from message */
 125         for (i = 0; msg->envp[i]; i++)
 126                 putenv(msg->envp[i]);
 127
 128         udev = udev_device_init(NULL);
 129         if (udev == NULL)
 130                 return -1;
 131         strlcpy(udev->action, msg->action, sizeof(udev->action));
 132         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 133         udev->devt = msg->devt;
 134
 135         retval = udev_device_event(&rules, udev);
 136
 137         /* run programs collected by RUN-key*/
 138         if (retval == 0 && !udev->ignore_device && udev_run) {
 139                 struct name_entry *name_loop;
 140
 141                 dbg("executing run list");
 142                 list_for_each_entry(name_loop, &udev->run_list, node) {
 143                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 144                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 145                         else {
 146                                 char program[PATH_SIZE];
 147
 148                                 strlcpy(program, name_loop->name, sizeof(program));
 149                                 udev_rules_apply_format(udev, program, sizeof(program));
 150                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 151                                                 (udev_log_priority >= LOG_INFO)) != 0)
 152                                         if (!name_loop->ignore_error)
 153                                                 retval = -1;
 154                         }
 155                 }
 156         }
 157
 158         udev_device_cleanup(udev);
 159         return retval;
 160 }
 161
 162 enum event_state {
 163         EVENT_QUEUED,
 164         EVENT_FINISHED,
 165         EVENT_FAILED,
 166 };
 167
 168 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 169 {
 170         char filename[PATH_SIZE];
 171         char filename_failed[PATH_SIZE];
 172         size_t start;
 173         struct udevd_uevent_msg *loop_msg;
 174         int fd;
 175
 176         /* add location of queue files */
 177         strlcpy(filename, udev_root, sizeof(filename));
 178         strlcat(filename, "/", sizeof(filename));
 179         start = strlcat(filename, EVENT_QUEUE_DIR"/", sizeof(filename));
 180         strlcat(filename, msg->devpath, sizeof(filename));
 181         path_encode(&filename[start], sizeof(filename) - start);
 182
 183         /* add location of failed files */
 184         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 185         strlcat(filename_failed, "/", sizeof(filename_failed));
 186         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 187         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 188         path_encode(&filename_failed[start], sizeof(filename) - start);
 189
 190         switch (state) {
 191         case EVENT_QUEUED:
 192                 unlink(filename_failed);
 193                 delete_path(filename_failed);
 194                 create_path(filename);
 195                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 196                 if (fd > 0)
 197                         close(fd);
 198                 return;
 199         case EVENT_FINISHED:
 200         case EVENT_FAILED:
 201                 unlink(filename_failed);
 202                 delete_path(filename_failed);
 203
 204                 /* don't remove, if events for the same path are still pending */
 205                 list_for_each_entry(loop_msg, &running_list, node)
 206                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 207                                 return;
 208
 209                 list_for_each_entry(loop_msg, &exec_list, node)
 210                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 211                                 return;
 212
 213                 /* move failed events to the failed directory */
 214                 if (state == EVENT_FAILED) {
 215                         create_path(filename_failed);
 216                         rename(filename, filename_failed);
 217                 } else {
 218                         unlink(filename);
 219                 }
 220
 221                 /* clean up the queue directory */
 222                 delete_path(filename);
 223
 224                 return;
 225         }
 226 }
 227
 228 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 229 {
 230         list_del(&msg->node);
 231
 232         /* mark as failed, if add event returns non-zero */
 233         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 234                 export_event_state(msg, EVENT_FAILED);
 235         else
 236                 export_event_state(msg, EVENT_FINISHED);
 237
 238         free(msg);
 239 }
 240
 241 static void udev_event_run(struct udevd_uevent_msg *msg)
 242 {
 243         pid_t pid;
 244         int retval;
 245
 246         pid = fork();
 247         switch (pid) {
 248         case 0:
 249                 /* child */
 250                 close(uevent_netlink_sock);
 251                 close(udevd_sock);
 252                 if (inotify_fd >= 0)
 253                         close(inotify_fd);
 254                 close(signal_pipe[READ_END]);
 255                 close(signal_pipe[WRITE_END]);
 256                 logging_close();
 257
 258                 logging_init("udevd-event");
 259                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 260
 261                 retval = udev_event_process(msg);
 262                 info("seq %llu finished with %i", msg->seqnum, retval);
 263
 264                 logging_close();
 265                 if (retval)
 266                         exit(1);
 267                 exit(0);
 268         case -1:
 269                 err("fork of child failed: %s", strerror(errno));
 270                 msg_queue_delete(msg);
 271                 break;
 272         default:
 273                 /* get SIGCHLD in main loop */
 274                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 275                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 276                 msg->pid = pid;
 277         }
 278 }
 279
 280 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 281 {
 282         char filename[PATH_SIZE];
 283         int fd;
 284
 285         msg->queue_time = time(NULL);
 286
 287         strlcpy(filename, udev_root, sizeof(filename));
 288         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 289         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 290         if (fd >= 0) {
 291                 char str[32];
 292                 int len;
 293
 294                 len = sprintf(str, "%llu\n", msg->seqnum);
 295                 write(fd, str, len);
 296                 close(fd);
 297         }
 298
 299         export_event_state(msg, EVENT_QUEUED);
 300
 301         /* run one event after the other in debug mode */
 302         if (debug_trace) {
 303                 list_add_tail(&msg->node, &running_list);
 304                 udev_event_run(msg);
 305                 waitpid(msg->pid, NULL, 0);
 306                 msg_queue_delete(msg);
 307                 return;
 308         }
 309
 310         /* run all events with a timeout set immediately */
 311         if (msg->timeout != 0) {
 312                 list_add_tail(&msg->node, &running_list);
 313                 udev_event_run(msg);
 314                 return;
 315         }
 316
 317         list_add_tail(&msg->node, &exec_list);
 318         run_exec_q = 1;
 319 }
 320
 321 static int mem_size_mb(void)
 322 {
 323         FILE* f;
 324         char buf[4096];
 325         long int memsize = -1;
 326
 327         f = fopen("/proc/meminfo", "r");
 328         if (f == NULL)
 329                 return -1;
 330
 331         while (fgets(buf, sizeof(buf), f) != NULL) {
 332                 long int value;
 333
 334                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 335                         memsize = value / 1024;
 336                         break;
 337                 }
 338         }
 339
 340         fclose(f);
 341         return memsize;
 342 }
 343
 344 static int cpu_count(void)
 345 {
 346         FILE* f;
 347         char buf[4096];
 348         int count = 0;
 349
 350         f = fopen("/proc/stat", "r");
 351         if (f == NULL)
 352                 return -1;
 353
 354         while (fgets(buf, sizeof(buf), f) != NULL) {
 355                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 356                         count++;
 357         }
 358
 359         fclose(f);
 360         if (count == 0)
 361                 return -1;
 362         return count;
 363 }
 364
 365 static int running_processes(void)
 366 {
 367         FILE* f;
 368         char buf[4096];
 369         int running = -1;
 370
 371         f = fopen("/proc/stat", "r");
 372         if (f == NULL)
 373                 return -1;
 374
 375         while (fgets(buf, sizeof(buf), f) != NULL) {
 376                 int value;
 377
 378                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 379                         running = value;
 380                         break;
 381                 }
 382         }
 383
 384         fclose(f);
 385         return running;
 386 }
 387
 388 /* return the number of process es in our session, count only until limit */
 389 static int running_processes_in_session(pid_t session, int limit)
 390 {
 391         DIR *dir;
 392         struct dirent *dent;
 393         int running = 0;
 394
 395         dir = opendir("/proc");
 396         if (!dir)
 397                 return -1;
 398
 399         /* read process info from /proc */
 400         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 401                 int f;
 402                 char procdir[64];
 403                 char line[256];
 404                 const char *pos;
 405                 char state;
 406                 pid_t ppid, pgrp, sess;
 407                 int len;
 408
 409                 if (!isdigit(dent->d_name[0]))
 410                         continue;
 411
 412                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 413                 procdir[sizeof(procdir)-1] = '\0';
 414
 415                 f = open(procdir, O_RDONLY);
 416                 if (f == -1)
 417                         continue;
 418
 419                 len = read(f, line, sizeof(line)-1);
 420                 close(f);
 421
 422                 if (len <= 0)
 423                         continue;
 424                 else
 425                         line[len] = '\0';
 426
 427                 /* skip ugly program name */
 428                 pos = strrchr(line, ')') + 2;
 429                 if (pos == NULL)
 430                         continue;
 431
 432                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 433                         continue;
 434
 435                 /* count only processes in our session */
 436                 if (sess != session)
 437                         continue;
 438
 439                 /* count only running, no sleeping processes */
 440                 if (state != 'R')
 441                         continue;
 442
 443                 running++;
 444                 if (limit > 0 && running >= limit)
 445                         break;
 446         }
 447         closedir(dir);
 448
 449         return running;
 450 }
 451
 452 static int compare_devpath(const char *running, const char *waiting)
 453 {
 454         int i;
 455
 456         for (i = 0; i < PATH_SIZE; i++) {
 457                 /* identical device event found */
 458                 if (running[i] == '\0' && waiting[i] == '\0')
 459                         return 1;
 460
 461                 /* parent device event found */
 462                 if (running[i] == '\0' && waiting[i] == '/')
 463                         return 2;
 464
 465                 /* child device event found */
 466                 if (running[i] == '/' && waiting[i] == '\0')
 467                         return 3;
 468
 469                 /* no matching event */
 470                 if (running[i] != waiting[i])
 471                         break;
 472         }
 473
 474         return 0;
 475 }
 476
 477 /* lookup event for identical, parent, child, or physical device */
 478 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 479 {
 480         struct udevd_uevent_msg *loop_msg;
 481         int childs_count = 0;
 482
 483         /* check exec-queue which may still contain delayed events we depend on */
 484         list_for_each_entry(loop_msg, &exec_list, node) {
 485                 /* skip ourself and all later events */
 486                 if (loop_msg->seqnum >= msg->seqnum)
 487                         break;
 488
 489                 /* check identical, parent, or child device event */
 490                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 491                         dbg("%llu, device event still pending %llu (%s)",
 492                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 493                         return 2;
 494                 }
 495
 496                 /* check physical device event (special case of parent) */
 497                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 498                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 499                                 dbg("%llu, physical device event still pending %llu (%s)",
 500                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 501                                 return 3;
 502                         }
 503         }
 504
 505         /* check runing-queue for still running events */
 506         list_for_each_entry(loop_msg, &running_list, node) {
 507                 if (limit && childs_count++ > limit) {
 508                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 509                         return 1;
 510                 }
 511
 512                 /* check identical, parent, or child device event */
 513                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 514                         dbg("%llu, device event still running %llu (%s)",
 515                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 516                         return 2;
 517                 }
 518
 519                 /* check physical device event (special case of parent) */
 520                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 521                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 522                                 dbg("%llu, physical device event still running %llu (%s)",
 523                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 524                                 return 3;
 525                         }
 526         }
 527         return 0;
 528 }
 529
 530 /* serializes events for the identical and parent and child devices */
 531 static void msg_queue_manager(void)
 532 {
 533         struct udevd_uevent_msg *loop_msg;
 534         struct udevd_uevent_msg *tmp_msg;
 535         int running;
 536
 537         if (list_empty(&exec_list))
 538                 return;
 539
 540         running = running_processes();
 541         dbg("%d processes runnning on system", running);
 542         if (running < 0)
 543                 running = max_childs_running;
 544
 545         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 546                 /* check running processes in our session and possibly throttle */
 547                 if (running >= max_childs_running) {
 548                         running = running_processes_in_session(sid, max_childs_running+10);
 549                         dbg("at least %d processes running in session", running);
 550                         if (running >= max_childs_running) {
 551                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 552                                 return;
 553                         }
 554                 }
 555
 556                 /* serialize and wait for parent or child events */
 557                 if (devpath_busy(loop_msg, max_childs) != 0) {
 558                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 559                         continue;
 560                 }
 561
 562                 /* move event to run list */
 563                 list_move_tail(&loop_msg->node, &running_list);
 564                 udev_event_run(loop_msg);
 565                 running++;
 566                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 567         }
 568 }
 569
 570 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 571 {
 572         int bufpos;
 573         int i;
 574         struct udevd_uevent_msg *msg;
 575         char *physdevdriver_key = NULL;
 576         int maj = 0;
 577         int min = 0;
 578
 579         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 580         if (msg == NULL)
 581                 return NULL;
 582         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 583
 584         /* copy environment buffer and reconstruct envp */
 585         memcpy(msg->envbuf, buf, buf_size);
 586         bufpos = 0;
 587         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 588                 int keylen;
 589                 char *key;
 590
 591                 key = &msg->envbuf[bufpos];
 592                 keylen = strlen(key);
 593                 msg->envp[i] = key;
 594                 bufpos += keylen + 1;
 595                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 596
 597                 /* remember some keys for further processing */
 598                 if (strncmp(key, "ACTION=", 7) == 0)
 599                         msg->action = &key[7];
 600                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 601                         msg->devpath = &key[8];
 602                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 603                         msg->subsystem = &key[10];
 604                 else if (strncmp(key, "DRIVER=", 7) == 0)
 605                         msg->driver = &key[7];
 606                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 607                         msg->seqnum = strtoull(&key[7], NULL, 10);
 608                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 609                         msg->physdevpath = &key[12];
 610                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 611                         physdevdriver_key = key;
 612                 else if (strncmp(key, "MAJOR=", 6) == 0)
 613                         maj = strtoull(&key[6], NULL, 10);
 614                 else if (strncmp(key, "MINOR=", 6) == 0)
 615                         min = strtoull(&key[6], NULL, 10);
 616                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 617                         msg->timeout = strtoull(&key[8], NULL, 10);
 618         }
 619         msg->devt = makedev(maj, min);
 620         msg->envp[i++] = "UDEVD_EVENT=1";
 621
 622         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 623                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 624                 msg->envp[i++] = &physdevdriver_key[7];
 625                 msg->driver = &physdevdriver_key[14];
 626         }
 627
 628         msg->envp[i] = NULL;
 629
 630         if (msg->devpath == NULL || msg->action == NULL) {
 631                 info("DEVPATH or ACTION missing, ignore message");
 632                 free(msg);
 633                 return NULL;
 634         }
 635         return msg;
 636 }
 637
 638 /* receive the udevd message from userspace */
 639 static void get_ctrl_msg(void)
 640 {
 641         struct udevd_ctrl_msg ctrl_msg;
 642         ssize_t size;
 643         struct msghdr smsg;
 644         struct cmsghdr *cmsg;
 645         struct iovec iov;
 646         struct ucred *cred;
 647         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 648         int *intval;
 649         char *pos;
 650
 651         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 652         iov.iov_base = &ctrl_msg;
 653         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 654
 655         memset(&smsg, 0x00, sizeof(struct msghdr));
 656         smsg.msg_iov = &iov;
 657         smsg.msg_iovlen = 1;
 658         smsg.msg_control = cred_msg;
 659         smsg.msg_controllen = sizeof(cred_msg);
 660
 661         size = recvmsg(udevd_sock, &smsg, 0);
 662         if (size <  0) {
 663                 if (errno != EINTR)
 664                         err("unable to receive user udevd message: %s", strerror(errno));
 665                 return;
 666         }
 667         cmsg = CMSG_FIRSTHDR(&smsg);
 668         cred = (struct ucred *) CMSG_DATA(cmsg);
 669
 670         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 671                 err("no sender credentials received, message ignored");
 672                 return;
 673         }
 674
 675         if (cred->uid != 0) {
 676                 err("sender uid=%i, message ignored", cred->uid);
 677                 return;
 678         }
 679
 680         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 681                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 682                 return;
 683         }
 684
 685         switch (ctrl_msg.type) {
 686         case UDEVD_CTRL_ENV:
 687                 pos = strchr(ctrl_msg.buf, '=');
 688                 if (pos == NULL) {
 689                         err("wrong key format '%s'", ctrl_msg.buf);
 690                         break;
 691                 }
 692                 pos[0] = '\0';
 693                 if (pos[1] == '\0') {
 694                         info("udevd message (ENV) received, unset '%s'", ctrl_msg.buf);
 695                         unsetenv(ctrl_msg.buf);
 696                 } else {
 697                         info("udevd message (ENV) received, set '%s=%s'", ctrl_msg.buf, &pos[1]);
 698                         setenv(ctrl_msg.buf, &pos[1], 1);
 699                 }
 700                 break;
 701         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 702                 info("udevd message (STOP_EXEC_QUEUE) received");
 703                 stop_exec_q = 1;
 704                 break;
 705         case UDEVD_CTRL_START_EXEC_QUEUE:
 706                 info("udevd message (START_EXEC_QUEUE) received");
 707                 stop_exec_q = 0;
 708                 msg_queue_manager();
 709                 break;
 710         case UDEVD_CTRL_SET_LOG_LEVEL:
 711                 intval = (int *) ctrl_msg.buf;
 712                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 713                 udev_log_priority = *intval;
 714                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 715                 putenv(udev_log);
 716                 break;
 717         case UDEVD_CTRL_SET_MAX_CHILDS:
 718                 intval = (int *) ctrl_msg.buf;
 719                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 720                 max_childs = *intval;
 721                 break;
 722         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 723                 intval = (int *) ctrl_msg.buf;
 724                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 725                 max_childs_running = *intval;
 726                 break;
 727         case UDEVD_CTRL_RELOAD_RULES:
 728                 info("udevd message (RELOAD_RULES) received");
 729                 reload_config = 1;
 730                 break;
 731         default:
 732                 err("unknown control message type");
 733         }
 734 }
 735
 736 /* receive the kernel user event message and do some sanity checks */
 737 static struct udevd_uevent_msg *get_netlink_msg(void)
 738 {
 739         struct udevd_uevent_msg *msg;
 740         int bufpos;
 741         ssize_t size;
 742         static char buffer[UEVENT_BUFFER_SIZE+512];
 743         char *pos;
 744
 745         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 746         if (size <  0) {
 747                 if (errno != EINTR)
 748                         err("unable to receive kernel netlink message: %s", strerror(errno));
 749                 return NULL;
 750         }
 751
 752         if ((size_t)size > sizeof(buffer)-1)
 753                 size = sizeof(buffer)-1;
 754         buffer[size] = '\0';
 755         dbg("uevent_size=%zi", size);
 756
 757         /* start of event payload */
 758         bufpos = strlen(buffer)+1;
 759         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 760         if (msg == NULL)
 761                 return NULL;
 762
 763         /* validate message */
 764         pos = strchr(buffer, '@');
 765         if (pos == NULL) {
 766                 err("invalid uevent '%s'", buffer);
 767                 free(msg);
 768                 return NULL;
 769         }
 770         pos[0] = '\0';
 771
 772         if (msg->action == NULL) {
 773                 info("no ACTION in payload found, skip event '%s'", buffer);
 774                 free(msg);
 775                 return NULL;
 776         }
 777
 778         if (strcmp(msg->action, buffer) != 0) {
 779                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 780                 free(msg);
 781                 return NULL;
 782         }
 783
 784         return msg;
 785 }
 786
 787 static void asmlinkage sig_handler(int signum)
 788 {
 789         switch (signum) {
 790                 case SIGINT:
 791                 case SIGTERM:
 792                         udev_exit = 1;
 793                         break;
 794                 case SIGCHLD:
 795                         /* set flag, then write to pipe if needed */
 796                         sigchilds_waiting = 1;
 797                         break;
 798                 case SIGHUP:
 799                         reload_config = 1;
 800                         break;
 801         }
 802
 803         /* write to pipe, which will wakeup select() in our mainloop */
 804         write(signal_pipe[WRITE_END], "", 1);
 805 }
 806
 807 static void udev_done(int pid, int exitstatus)
 808 {
 809         /* find msg associated with pid and delete it */
 810         struct udevd_uevent_msg *msg;
 811
 812         list_for_each_entry(msg, &running_list, node) {
 813                 if (msg->pid == pid) {
 814                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 815                              exitstatus, time(NULL) - msg->queue_time);
 816                         msg->exitstatus = exitstatus;
 817                         msg_queue_delete(msg);
 818
 819                         /* there may be events waiting with the same devpath */
 820                         run_exec_q = 1;
 821                         return;
 822                 }
 823         }
 824 }
 825
 826 static void reap_sigchilds(void)
 827 {
 828         pid_t pid;
 829         int status;
 830
 831         while (1) {
 832                 pid = waitpid(-1, &status, WNOHANG);
 833                 if (pid <= 0)
 834                         break;
 835                 if (WIFEXITED(status))
 836                         status = WEXITSTATUS(status);
 837                 else if (WIFSIGNALED(status))
 838                         status = WTERMSIG(status) + 128;
 839                 else
 840                         status = 0;
 841                 udev_done(pid, status);
 842         }
 843 }
 844
 845 static int init_udevd_socket(void)
 846 {
 847         struct sockaddr_un saddr;
 848         socklen_t addrlen;
 849         const int feature_on = 1;
 850         int retval;
 851
 852         memset(&saddr, 0x00, sizeof(saddr));
 853         saddr.sun_family = AF_LOCAL;
 854         /* use abstract namespace for socket path */
 855         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 856         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 857
 858         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 859         if (udevd_sock == -1) {
 860                 err("error getting socket: %s", strerror(errno));
 861                 return -1;
 862         }
 863
 864         /* the bind takes care of ensuring only one copy running */
 865         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 866         if (retval < 0) {
 867                 err("bind failed: %s", strerror(errno));
 868                 close(udevd_sock);
 869                 udevd_sock = -1;
 870                 return -1;
 871         }
 872
 873         /* enable receiving of the sender credentials */
 874         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 875
 876         return 0;
 877 }
 878
 879 static int init_uevent_netlink_sock(void)
 880 {
 881         struct sockaddr_nl snl;
 882         const int buffersize = 16 * 1024 * 1024;
 883         int retval;
 884
 885         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 886         snl.nl_family = AF_NETLINK;
 887         snl.nl_pid = getpid();
 888         snl.nl_groups = 1;
 889
 890         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 891         if (uevent_netlink_sock == -1) {
 892                 err("error getting socket: %s", strerror(errno));
 893                 return -1;
 894         }
 895
 896         /* set receive buffersize */
 897         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 898
 899         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 900         if (retval < 0) {
 901                 err("bind failed: %s", strerror(errno));
 902                 close(uevent_netlink_sock);
 903                 uevent_netlink_sock = -1;
 904                 return -1;
 905         }
 906         return 0;
 907 }
 908
 909 static void export_initial_seqnum(void)
 910 {
 911         char filename[PATH_SIZE];
 912         int fd;
 913         char seqnum[32];
 914         ssize_t len = 0;
 915
 916         strlcpy(filename, sysfs_path, sizeof(filename));
 917         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 918         fd = open(filename, O_RDONLY);
 919         if (fd >= 0) {
 920                 len = read(fd, seqnum, sizeof(seqnum)-1);
 921                 close(fd);
 922         }
 923         if (len <= 0) {
 924                 strcpy(seqnum, "0\n");
 925                 len = 3;
 926         }
 927         strlcpy(filename, udev_root, sizeof(filename));
 928         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 929         create_path(filename);
 930         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 931         if (fd >= 0) {
 932                 write(fd, seqnum, len);
 933                 close(fd);
 934         }
 935 }
 936
 937 int main(int argc, char *argv[], char *envp[])
 938 {
 939         int retval;
 940         int fd;
 941         struct sigaction act;
 942         fd_set readfds;
 943         const char *value;
 944         int daemonize = 0;
 945         int option;
 946         static const struct option options[] = {
 947                 { "daemon", 0, NULL, 'd' },
 948                 { "debug-trace", 0, NULL, 't' },
 949                 { "verbose", 0, NULL, 'v' },
 950                 { "help", 0, NULL, 'h' },
 951                 { "version", 0, NULL, 'V' },
 952                 {}
 953         };
 954         int rc = 1;
 955         int maxfd;
 956
 957         logging_init("udevd");
 958         udev_config_init();
 959         selinux_init();
 960         dbg("version %s", UDEV_VERSION);
 961
 962         while (1) {
 963                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 964                 if (option == -1)
 965                         break;
 966
 967                 switch (option) {
 968                 case 'd':
 969                         daemonize = 1;
 970                         break;
 971                 case 't':
 972                         debug_trace = 1;
 973                         break;
 974                 case 'v':
 975                         verbose = 1;
 976                         if (udev_log_priority < LOG_INFO)
 977                                 udev_log_priority = LOG_INFO;
 978                         break;
 979                 case 'h':
 980                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 981                         goto exit;
 982                 case 'V':
 983                         printf("%s\n", UDEV_VERSION);
 984                         goto exit;
 985                 default:
 986                         goto exit;
 987                 }
 988         }
 989
 990         if (getuid() != 0) {
 991                 fprintf(stderr, "root privileges required\n");
 992                 err("root privileges required");
 993                 goto exit;
 994         }
 995
 996         /* make sure std{in,out,err} fd's are in a sane state */
 997         fd = open("/dev/null", O_RDWR);
 998         if (fd < 0) {
 999                 fprintf(stderr, "cannot open /dev/null\n");
1000                 err("cannot open /dev/null");
1001         }
1002         if (fd > STDIN_FILENO)
1003                 dup2(fd, STDIN_FILENO);
1004         if (write(STDOUT_FILENO, 0, 0) < 0)
1005                 dup2(fd, STDOUT_FILENO);
1006         if (write(STDERR_FILENO, 0, 0) < 0)
1007                 dup2(fd, STDERR_FILENO);
1008
1009         /* init sockets to receive events */
1010         if (init_udevd_socket() < 0) {
1011                 if (errno == EADDRINUSE) {
1012                         fprintf(stderr, "another udev daemon already running\n");
1013                         err("another udev daemon already running");
1014                         rc = 1;
1015                 } else {
1016                         fprintf(stderr, "error initializing udevd socket\n");
1017                         err("error initializing udevd socket");
1018                         rc = 2;
1019                 }
1020                 goto exit;
1021         }
1022
1023         if (init_uevent_netlink_sock() < 0) {
1024                 fprintf(stderr, "error initializing netlink socket\n");
1025                 err("error initializing netlink socket");
1026                 rc = 3;
1027                 goto exit;
1028         }
1029
1030         /* setup signal handler pipe */
1031         retval = pipe(signal_pipe);
1032         if (retval < 0) {
1033                 err("error getting pipes: %s", strerror(errno));
1034                 goto exit;
1035         }
1036
1037         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1038         if (retval < 0) {
1039                 err("error fcntl on read pipe: %s", strerror(errno));
1040                 goto exit;
1041         }
1042         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1043         if (retval < 0) {
1044                 err("error fcntl on read pipe: %s", strerror(errno));
1045                 goto exit;
1046         }
1047
1048         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1049         if (retval < 0) {
1050                 err("error fcntl on write pipe: %s", strerror(errno));
1051                 goto exit;
1052         }
1053         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1054         if (retval < 0) {
1055                 err("error fcntl on write pipe: %s", strerror(errno));
1056                 goto exit;
1057         }
1058
1059         /* parse the rules and keep them in memory */
1060         sysfs_init();
1061         udev_rules_init(&rules, 1);
1062
1063         export_initial_seqnum();
1064
1065         if (daemonize) {
1066                 pid_t pid;
1067
1068                 pid = fork();
1069                 switch (pid) {
1070                 case 0:
1071                         dbg("daemonized fork running");
1072                         break;
1073                 case -1:
1074                         err("fork of daemon failed: %s", strerror(errno));
1075                         rc = 4;
1076                         goto exit;
1077                 default:
1078                         dbg("child [%u] running, parent exits", pid);
1079                         rc = 0;
1080                         goto exit;
1081                 }
1082         }
1083
1084         /* redirect std{out,err} fd's */
1085         if (!verbose)
1086                 dup2(fd, STDOUT_FILENO);
1087         dup2(fd, STDERR_FILENO);
1088         if (fd > STDERR_FILENO)
1089                 close(fd);
1090
1091         /* set scheduling priority for the daemon */
1092         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1093
1094         chdir("/");
1095         umask(022);
1096
1097         /* become session leader */
1098         sid = setsid();
1099         dbg("our session is %d", sid);
1100
1101         /* OOM_DISABLE == -17 */
1102         fd = open("/proc/self/oom_adj", O_RDWR);
1103         if (fd < 0)
1104                 err("error disabling OOM: %s", strerror(errno));
1105         else {
1106                 write(fd, "-17", 3);
1107                 close(fd);
1108         }
1109
1110         /* set signal handlers */
1111         memset(&act, 0x00, sizeof(struct sigaction));
1112         act.sa_handler = (void (*)(int)) sig_handler;
1113         sigemptyset(&act.sa_mask);
1114         act.sa_flags = SA_RESTART;
1115         sigaction(SIGINT, &act, NULL);
1116         sigaction(SIGTERM, &act, NULL);
1117         sigaction(SIGCHLD, &act, NULL);
1118         sigaction(SIGHUP, &act, NULL);
1119
1120         /* watch rules directory */
1121         inotify_fd = inotify_init();
1122         if (inotify_fd >= 0)
1123                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1124         else if (errno == ENOSYS)
1125                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1126         else
1127                 err("inotify_init failed: %s", strerror(errno));
1128
1129         /* maximum limit of forked childs */
1130         value = getenv("UDEVD_MAX_CHILDS");
1131         if (value)
1132                 max_childs = strtoul(value, NULL, 10);
1133         else {
1134                 int memsize = mem_size_mb();
1135                 if (memsize > 0)
1136                         max_childs = 128 + (memsize / 4);
1137                 else
1138                         max_childs = UDEVD_MAX_CHILDS;
1139         }
1140         info("initialize max_childs to %u", max_childs);
1141
1142         /* start to throttle forking if maximum number of _running_ childs is reached */
1143         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1144         if (value)
1145                 max_childs_running = strtoull(value, NULL, 10);
1146         else {
1147                 int cpus = cpu_count();
1148                 if (cpus > 0)
1149                         max_childs_running = 8 + (8 * cpus);
1150                 else
1151                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1152         }
1153         info("initialize max_childs_running to %u", max_childs_running);
1154
1155         /* clear environment for forked event processes */
1156         clearenv();
1157
1158         /* export log_priority , as called programs may want to follow that setting */
1159         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1160         putenv(udev_log);
1161         if (debug_trace)
1162                 putenv("DEBUG=1");
1163
1164         maxfd = udevd_sock;
1165         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1166         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1167         maxfd = UDEV_MAX(maxfd, inotify_fd);
1168
1169         while (!udev_exit) {
1170                 struct udevd_uevent_msg *msg;
1171                 int fdcount;
1172
1173                 FD_ZERO(&readfds);
1174                 FD_SET(signal_pipe[READ_END], &readfds);
1175                 FD_SET(udevd_sock, &readfds);
1176                 FD_SET(uevent_netlink_sock, &readfds);
1177                 if (inotify_fd >= 0)
1178                         FD_SET(inotify_fd, &readfds);
1179
1180                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1181                 if (fdcount < 0) {
1182                         if (errno != EINTR)
1183                                 err("error in select: %s", strerror(errno));
1184                         continue;
1185                 }
1186
1187                 /* get control message */
1188                 if (FD_ISSET(udevd_sock, &readfds))
1189                         get_ctrl_msg();
1190
1191                 /* get netlink message */
1192                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1193                         msg = get_netlink_msg();
1194                         if (msg)
1195                                 msg_queue_insert(msg);
1196                 }
1197
1198                 /* received a signal, clear our notification pipe */
1199                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1200                         char buf[256];
1201
1202                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1203                 }
1204
1205                 /* rules directory inotify watch */
1206                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1207                         int nbytes;
1208
1209                         /* discard all possible events, we can just reload the config */
1210                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1211                                 char *buf;
1212
1213                                 reload_config = 1;
1214                                 buf = malloc(nbytes);
1215                                 if (!buf) {
1216                                         err("error getting buffer for inotify, disable watching");
1217                                         close(inotify_fd);
1218                                         inotify_fd = -1;
1219                                 }
1220                                 read(inotify_fd, buf, nbytes);
1221                                 free(buf);
1222                         }
1223                 }
1224
1225                 /* rules changed, set by inotify or a HUP signal */
1226                 if (reload_config) {
1227                         reload_config = 0;
1228                         udev_rules_cleanup(&rules);
1229                         udev_rules_init(&rules, 1);
1230                 }
1231
1232                 /* forked child has returned */
1233                 if (sigchilds_waiting) {
1234                         sigchilds_waiting = 0;
1235                         reap_sigchilds();
1236                 }
1237
1238                 if (run_exec_q) {
1239                         run_exec_q = 0;
1240                         if (!stop_exec_q)
1241                                 msg_queue_manager();
1242                 }
1243         }
1244         rc = 0;
1245
1246 exit:
1247         udev_rules_cleanup(&rules);
1248         sysfs_cleanup();
1249         selinux_exit();
1250
1251         if (signal_pipe[READ_END] >= 0)
1252                 close(signal_pipe[READ_END]);
1253         if (signal_pipe[WRITE_END] >= 0)
1254                 close(signal_pipe[WRITE_END]);
1255
1256         if (udevd_sock >= 0)
1257                 close(udevd_sock);
1258         if (inotify_fd >= 0)
1259                 close(inotify_fd);
1260         if (uevent_netlink_sock >= 0)
1261                 close(uevent_netlink_sock);
1262
1263         logging_close();
1264
1265         return rc;
1266 }