udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static int debug_trace;
  49 static int verbose;
  50
  51 static struct udev_rules rules;
  52 static int udevd_sock = -1;
  53 static int uevent_netlink_sock = -1;
  54 static int inotify_fd = -1;
  55 static pid_t sid;
  56
  57 static int signal_pipe[2] = {-1, -1};
  58 static volatile int sigchilds_waiting;
  59 static volatile int udev_exit;
  60 static volatile int reload_config;
  61 static int run_exec_q;
  62 static int stop_exec_q;
  63 static int max_childs;
  64 static int max_childs_running;
  65 static char udev_log[32];
  66
  67 static LIST_HEAD(exec_list);
  68 static LIST_HEAD(running_list);
  69
  70
  71 #ifdef USE_LOG
  72 void log_message(int priority, const char *format, ...)
  73 {
  74         va_list args;
  75
  76         if (priority > udev_log_priority)
  77                 return;
  78
  79         va_start(args, format);
  80         vsyslog(priority, format, args);
  81         va_end(args);
  82
  83         if (verbose) {
  84                 va_start(args, format);
  85                 vprintf(format, args);
  86                 va_end(args);
  87                 printf("\n");
  88         }
  89 }
  90
  91 #endif
  92
  93 static void asmlinkage udev_event_sig_handler(int signum)
  94 {
  95         if (signum == SIGALRM)
  96                 exit(1);
  97 }
  98
  99 static int udev_event_process(struct udevd_uevent_msg *msg)
 100 {
 101         struct sigaction act;
 102         struct udevice *udev;
 103         int i;
 104         int retval;
 105
 106         /* set signal handlers */
 107         memset(&act, 0x00, sizeof(act));
 108         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 109         sigemptyset (&act.sa_mask);
 110         act.sa_flags = 0;
 111         sigaction(SIGALRM, &act, NULL);
 112
 113         /* reset to default */
 114         act.sa_handler = SIG_DFL;
 115         sigaction(SIGINT, &act, NULL);
 116         sigaction(SIGTERM, &act, NULL);
 117         sigaction(SIGCHLD, &act, NULL);
 118         sigaction(SIGHUP, &act, NULL);
 119
 120         /* trigger timeout to prevent hanging processes */
 121         alarm(UDEV_ALARM_TIMEOUT);
 122
 123         /* reconstruct event environment from message */
 124         for (i = 0; msg->envp[i]; i++)
 125                 putenv(msg->envp[i]);
 126
 127         udev = udev_device_init();
 128         if (udev == NULL)
 129                 return -1;
 130         strlcpy(udev->action, msg->action, sizeof(udev->action));
 131         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 132         udev->devt = msg->devt;
 133
 134         retval = udev_device_event(&rules, udev);
 135
 136         /* run programs collected by RUN-key*/
 137         if (retval == 0 && !udev->ignore_device && udev_run) {
 138                 struct name_entry *name_loop;
 139
 140                 dbg("executing run list");
 141                 list_for_each_entry(name_loop, &udev->run_list, node) {
 142                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 143                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 144                         else {
 145                                 char program[PATH_SIZE];
 146
 147                                 strlcpy(program, name_loop->name, sizeof(program));
 148                                 udev_rules_apply_format(udev, program, sizeof(program));
 149                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 150                                                 (udev_log_priority >= LOG_INFO)))
 151                                         retval = -1;
 152                         }
 153                 }
 154         }
 155
 156         udev_device_cleanup(udev);
 157         return retval;
 158 }
 159
 160 enum event_state {
 161         EVENT_QUEUED,
 162         EVENT_FINISHED,
 163         EVENT_FAILED,
 164 };
 165
 166 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 167 {
 168         char filename[PATH_SIZE];
 169         char filename_failed[PATH_SIZE];
 170         size_t start, end, i;
 171         struct udevd_uevent_msg *loop_msg;
 172         int fd;
 173
 174         /* add location of queue files */
 175         strlcpy(filename, udev_root, sizeof(filename));
 176         strlcat(filename, "/", sizeof(filename));
 177         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 178         end = strlcat(filename, msg->devpath, sizeof(filename));
 179         if (end > sizeof(filename))
 180                 end = sizeof(filename);
 181
 182         /* replace '/' to transform path into a filename */
 183         for (i = start+1; i < end; i++)
 184                 if (filename[i] == '/')
 185                         filename[i] = PATH_TO_NAME_CHAR;
 186
 187         /* add location of failed files */
 188         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 189         strlcat(filename_failed, "/", sizeof(filename_failed));
 190         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 191         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 192         if (end > sizeof(filename_failed))
 193                 end = sizeof(filename_failed);
 194
 195         /* replace '/' to transform path into a filename */
 196         for (i = start+1; i < end; i++)
 197                 if (filename_failed[i] == '/')
 198                         filename_failed[i] = PATH_TO_NAME_CHAR;
 199
 200         switch (state) {
 201         case EVENT_QUEUED:
 202                 unlink(filename_failed);
 203                 delete_path(filename_failed);
 204                 create_path(filename);
 205                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 206                 if (fd > 0)
 207                         close(fd);
 208                 return;
 209         case EVENT_FINISHED:
 210         case EVENT_FAILED:
 211                 unlink(filename_failed);
 212                 delete_path(filename_failed);
 213
 214                 /* don't remove, if events for the same path are still pending */
 215                 list_for_each_entry(loop_msg, &running_list, node)
 216                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 217                                 return;
 218
 219                 list_for_each_entry(loop_msg, &exec_list, node)
 220                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 221                                 return;
 222
 223                 /* move failed events to the failed directory */
 224                 if (state == EVENT_FAILED) {
 225                         create_path(filename_failed);
 226                         rename(filename, filename_failed);
 227                 } else {
 228                         unlink(filename);
 229                 }
 230
 231                 /* clean up the queue directory */
 232                 delete_path(filename);
 233
 234                 return;
 235         }
 236 }
 237
 238 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 239 {
 240         list_del(&msg->node);
 241
 242         /* mark as failed, if add event returns non-zero */
 243         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 244                 export_event_state(msg, EVENT_FAILED);
 245         else
 246                 export_event_state(msg, EVENT_FINISHED);
 247
 248         free(msg);
 249 }
 250
 251 static void udev_event_run(struct udevd_uevent_msg *msg)
 252 {
 253         pid_t pid;
 254         int retval;
 255
 256         pid = fork();
 257         switch (pid) {
 258         case 0:
 259                 /* child */
 260                 close(uevent_netlink_sock);
 261                 close(udevd_sock);
 262                 if (inotify_fd >= 0)
 263                         close(inotify_fd);
 264                 close(signal_pipe[READ_END]);
 265                 close(signal_pipe[WRITE_END]);
 266                 logging_close();
 267
 268                 logging_init("udevd-event");
 269                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 270
 271                 retval = udev_event_process(msg);
 272                 info("seq %llu finished", msg->seqnum);
 273
 274                 logging_close();
 275                 if (retval)
 276                         exit(1);
 277                 exit(0);
 278         case -1:
 279                 err("fork of child failed: %s", strerror(errno));
 280                 msg_queue_delete(msg);
 281                 break;
 282         default:
 283                 /* get SIGCHLD in main loop */
 284                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 285                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 286                 msg->pid = pid;
 287         }
 288 }
 289
 290 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 291 {
 292         char filename[PATH_SIZE];
 293         int fd;
 294
 295         msg->queue_time = time(NULL);
 296
 297         strlcpy(filename, udev_root, sizeof(filename));
 298         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 299         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 300         if (fd >= 0) {
 301                 char str[32];
 302                 int len;
 303
 304                 len = sprintf(str, "%llu\n", msg->seqnum);
 305                 write(fd, str, len);
 306                 close(fd);
 307         }
 308
 309         export_event_state(msg, EVENT_QUEUED);
 310
 311         /* run one event after the other in debug mode */
 312         if (debug_trace) {
 313                 list_add_tail(&msg->node, &running_list);
 314                 udev_event_run(msg);
 315                 waitpid(msg->pid, NULL, 0);
 316                 msg_queue_delete(msg);
 317                 return;
 318         }
 319
 320         /* run all events with a timeout set immediately */
 321         if (msg->timeout != 0) {
 322                 list_add_tail(&msg->node, &running_list);
 323                 udev_event_run(msg);
 324                 return;
 325         }
 326
 327         list_add_tail(&msg->node, &exec_list);
 328         run_exec_q = 1;
 329 }
 330
 331 static int mem_size_mb(void)
 332 {
 333         int f;
 334         char buf[8192];
 335         long int len;
 336         const char *pos;
 337         long int memsize;
 338
 339         f = open("/proc/meminfo", O_RDONLY);
 340         if (f == -1)
 341                 return -1;
 342
 343         len = read(f, buf, sizeof(buf)-1);
 344         close(f);
 345
 346         if (len <= 0)
 347                 return -1;
 348         buf[len] = '\0';
 349
 350         pos = strstr(buf, "MemTotal: ");
 351         if (pos == NULL)
 352                 return -1;
 353
 354         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 355                 return -1;
 356
 357         return memsize / 1024;
 358 }
 359
 360 static int cpu_count(void)
 361 {
 362         int f;
 363         char buf[32768];
 364         int len;
 365         const char *pos;
 366         int count = 0;
 367
 368         f = open("/proc/stat", O_RDONLY);
 369         if (f == -1)
 370                 return -1;
 371
 372         len = read(f, buf, sizeof(buf)-1);
 373         close(f);
 374         if (len <= 0)
 375                 return -1;
 376         buf[len] = '\0';
 377
 378         pos = strstr(buf, "cpu");
 379         if (pos == NULL)
 380                 return -1;
 381
 382         while (pos != NULL) {
 383                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 384                         count++;
 385                 pos = strstr(&pos[3], "cpu");
 386         }
 387
 388         if (count == 0)
 389                 return -1;
 390         return count;
 391 }
 392
 393 static int running_processes(void)
 394 {
 395         int f;
 396         char buf[32768];
 397         int len;
 398         int running;
 399         const char *pos;
 400
 401         f = open("/proc/stat", O_RDONLY);
 402         if (f == -1)
 403                 return -1;
 404
 405         len = read(f, buf, sizeof(buf)-1);
 406         close(f);
 407         if (len <= 0)
 408                 return -1;
 409         buf[len] = '\0';
 410
 411         pos = strstr(buf, "procs_running ");
 412         if (pos == NULL)
 413                 return -1;
 414
 415         if (sscanf(pos, "procs_running %u", &running) != 1)
 416                 return -1;
 417
 418         return running;
 419 }
 420
 421 /* return the number of process es in our session, count only until limit */
 422 static int running_processes_in_session(pid_t session, int limit)
 423 {
 424         DIR *dir;
 425         struct dirent *dent;
 426         int running = 0;
 427
 428         dir = opendir("/proc");
 429         if (!dir)
 430                 return -1;
 431
 432         /* read process info from /proc */
 433         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 434                 int f;
 435                 char procdir[64];
 436                 char line[256];
 437                 const char *pos;
 438                 char state;
 439                 pid_t ppid, pgrp, sess;
 440                 int len;
 441
 442                 if (!isdigit(dent->d_name[0]))
 443                         continue;
 444
 445                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 446                 procdir[sizeof(procdir)-1] = '\0';
 447
 448                 f = open(procdir, O_RDONLY);
 449                 if (f == -1)
 450                         continue;
 451
 452                 len = read(f, line, sizeof(line)-1);
 453                 close(f);
 454
 455                 if (len <= 0)
 456                         continue;
 457                 else
 458                         line[len] = '\0';
 459
 460                 /* skip ugly program name */
 461                 pos = strrchr(line, ')') + 2;
 462                 if (pos == NULL)
 463                         continue;
 464
 465                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 466                         continue;
 467
 468                 /* count only processes in our session */
 469                 if (sess != session)
 470                         continue;
 471
 472                 /* count only running, no sleeping processes */
 473                 if (state != 'R')
 474                         continue;
 475
 476                 running++;
 477                 if (limit > 0 && running >= limit)
 478                         break;
 479         }
 480         closedir(dir);
 481
 482         return running;
 483 }
 484
 485 static int compare_devpath(const char *running, const char *waiting)
 486 {
 487         int i;
 488
 489         for (i = 0; i < PATH_SIZE; i++) {
 490                 /* identical device event found */
 491                 if (running[i] == '\0' && waiting[i] == '\0')
 492                         return 1;
 493
 494                 /* parent device event found */
 495                 if (running[i] == '\0' && waiting[i] == '/')
 496                         return 2;
 497
 498                 /* child device event found */
 499                 if (running[i] == '/' && waiting[i] == '\0')
 500                         return 3;
 501
 502                 /* no matching event */
 503                 if (running[i] != waiting[i])
 504                         break;
 505         }
 506
 507         return 0;
 508 }
 509
 510 /* returns still running task for the same device, its parent or its physical device */
 511 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 512 {
 513         struct udevd_uevent_msg *loop_msg;
 514         int childs_count = 0;
 515
 516         list_for_each_entry(loop_msg, &running_list, node) {
 517                 if (limit && childs_count++ > limit) {
 518                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 519                         return 1;
 520                 }
 521
 522                 /* return running parent/child device event */
 523                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 524                         dbg("%llu, child device event still running %llu (%s)",
 525                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 526                         return 2;
 527                 }
 528
 529                 /* return running physical device event */
 530                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 531                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 532                                 dbg("%llu, physical device event still running %llu (%s)",
 533                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 534                                 return 3;
 535                         }
 536         }
 537
 538         return 0;
 539 }
 540
 541 /* exec queue management routine executes the events and serializes events in the same sequence */
 542 static void msg_queue_manager(void)
 543 {
 544         struct udevd_uevent_msg *loop_msg;
 545         struct udevd_uevent_msg *tmp_msg;
 546         int running;
 547
 548         if (list_empty(&exec_list))
 549                 return;
 550
 551         running = running_processes();
 552         dbg("%d processes runnning on system", running);
 553         if (running < 0)
 554                 running = max_childs_running;
 555
 556         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 557                 /* check running processes in our session and possibly throttle */
 558                 if (running >= max_childs_running) {
 559                         running = running_processes_in_session(sid, max_childs_running+10);
 560                         dbg("at least %d processes running in session", running);
 561                         if (running >= max_childs_running) {
 562                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 563                                 return;
 564                         }
 565                 }
 566
 567                 /* don't run two processes for the same devpath and wait for the parent*/
 568                 if (running_with_devpath(loop_msg, max_childs)) {
 569                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 570                         continue;
 571                 }
 572
 573                 /* move event to run list */
 574                 list_move_tail(&loop_msg->node, &running_list);
 575                 udev_event_run(loop_msg);
 576                 running++;
 577                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 578         }
 579 }
 580
 581 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 582 {
 583         int bufpos;
 584         int i;
 585         struct udevd_uevent_msg *msg;
 586         char *physdevdriver_key = NULL;
 587         int maj = 0;
 588         int min = 0;
 589
 590         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 591         if (msg == NULL)
 592                 return NULL;
 593         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 594
 595         /* copy environment buffer and reconstruct envp */
 596         memcpy(msg->envbuf, buf, buf_size);
 597         bufpos = 0;
 598         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 599                 int keylen;
 600                 char *key;
 601
 602                 key = &msg->envbuf[bufpos];
 603                 keylen = strlen(key);
 604                 msg->envp[i] = key;
 605                 bufpos += keylen + 1;
 606                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 607
 608                 /* remember some keys for further processing */
 609                 if (strncmp(key, "ACTION=", 7) == 0)
 610                         msg->action = &key[7];
 611                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 612                         msg->devpath = &key[8];
 613                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 614                         msg->subsystem = &key[10];
 615                 else if (strncmp(key, "DRIVER=", 7) == 0)
 616                         msg->driver = &key[7];
 617                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 618                         msg->seqnum = strtoull(&key[7], NULL, 10);
 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
 661         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 662         iov.iov_base = &ctrl_msg;
 663         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 664
 665         memset(&smsg, 0x00, sizeof(struct msghdr));
 666         smsg.msg_iov = &iov;
 667         smsg.msg_iovlen = 1;
 668         smsg.msg_control = cred_msg;
 669         smsg.msg_controllen = sizeof(cred_msg);
 670
 671         size = recvmsg(udevd_sock, &smsg, 0);
 672         if (size <  0) {
 673                 if (errno != EINTR)
 674                         err("unable to receive user udevd message: %s", strerror(errno));
 675                 return;
 676         }
 677         cmsg = CMSG_FIRSTHDR(&smsg);
 678         cred = (struct ucred *) CMSG_DATA(cmsg);
 679
 680         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 681                 err("no sender credentials received, message ignored");
 682                 return;
 683         }
 684
 685         if (cred->uid != 0) {
 686                 err("sender uid=%i, message ignored", cred->uid);
 687                 return;
 688         }
 689
 690         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 691                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 692                 return;
 693         }
 694
 695         switch (ctrl_msg.type) {
 696         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 697                 info("udevd message (STOP_EXEC_QUEUE) received");
 698                 stop_exec_q = 1;
 699                 break;
 700         case UDEVD_CTRL_START_EXEC_QUEUE:
 701                 info("udevd message (START_EXEC_QUEUE) received");
 702                 stop_exec_q = 0;
 703                 msg_queue_manager();
 704                 break;
 705         case UDEVD_CTRL_SET_LOG_LEVEL:
 706                 intval = (int *) ctrl_msg.buf;
 707                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 708                 udev_log_priority = *intval;
 709                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 710                 putenv(udev_log);
 711                 break;
 712         case UDEVD_CTRL_SET_MAX_CHILDS:
 713                 intval = (int *) ctrl_msg.buf;
 714                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 715                 max_childs = *intval;
 716                 break;
 717         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 718                 intval = (int *) ctrl_msg.buf;
 719                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 720                 max_childs_running = *intval;
 721                 break;
 722         case UDEVD_CTRL_RELOAD_RULES:
 723                 info("udevd message (RELOAD_RULES) received");
 724                 reload_config = 1;
 725                 break;
 726         default:
 727                 err("unknown control message type");
 728         }
 729 }
 730
 731 /* receive the kernel user event message and do some sanity checks */
 732 static struct udevd_uevent_msg *get_netlink_msg(void)
 733 {
 734         struct udevd_uevent_msg *msg;
 735         int bufpos;
 736         ssize_t size;
 737         static char buffer[UEVENT_BUFFER_SIZE+512];
 738         char *pos;
 739
 740         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 741         if (size <  0) {
 742                 if (errno != EINTR)
 743                         err("unable to receive kernel netlink message: %s", strerror(errno));
 744                 return NULL;
 745         }
 746
 747         if ((size_t)size > sizeof(buffer)-1)
 748                 size = sizeof(buffer)-1;
 749         buffer[size] = '\0';
 750         dbg("uevent_size=%zi", size);
 751
 752         /* start of event payload */
 753         bufpos = strlen(buffer)+1;
 754         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 755         if (msg == NULL)
 756                 return NULL;
 757
 758         /* validate message */
 759         pos = strchr(buffer, '@');
 760         if (pos == NULL) {
 761                 err("invalid uevent '%s'", buffer);
 762                 free(msg);
 763                 return NULL;
 764         }
 765         pos[0] = '\0';
 766
 767         if (msg->action == NULL) {
 768                 info("no ACTION in payload found, skip event '%s'", buffer);
 769                 free(msg);
 770                 return NULL;
 771         }
 772
 773         if (strcmp(msg->action, buffer) != 0) {
 774                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 775                 free(msg);
 776                 return NULL;
 777         }
 778
 779         return msg;
 780 }
 781
 782 static void asmlinkage sig_handler(int signum)
 783 {
 784         switch (signum) {
 785                 case SIGINT:
 786                 case SIGTERM:
 787                         udev_exit = 1;
 788                         break;
 789                 case SIGCHLD:
 790                         /* set flag, then write to pipe if needed */
 791                         sigchilds_waiting = 1;
 792                         break;
 793                 case SIGHUP:
 794                         reload_config = 1;
 795                         break;
 796         }
 797
 798         /* write to pipe, which will wakeup select() in our mainloop */
 799         write(signal_pipe[WRITE_END], "", 1);
 800 }
 801
 802 static void udev_done(int pid, int exitstatus)
 803 {
 804         /* find msg associated with pid and delete it */
 805         struct udevd_uevent_msg *msg;
 806
 807         list_for_each_entry(msg, &running_list, node) {
 808                 if (msg->pid == pid) {
 809                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 810                              exitstatus, time(NULL) - msg->queue_time);
 811                         msg->exitstatus = exitstatus;
 812                         msg_queue_delete(msg);
 813
 814                         /* there may be events waiting with the same devpath */
 815                         run_exec_q = 1;
 816                         return;
 817                 }
 818         }
 819 }
 820
 821 static void reap_sigchilds(void)
 822 {
 823         pid_t pid;
 824         int status;
 825
 826         while (1) {
 827                 pid = waitpid(-1, &status, WNOHANG);
 828                 if (pid <= 0)
 829                         break;
 830                 if (WIFEXITED(status))
 831                         status = WEXITSTATUS(status);
 832                 else if (WIFSIGNALED(status))
 833                         status = WTERMSIG(status) + 128;
 834                 else
 835                         status = 0;
 836                 udev_done(pid, status);
 837         }
 838 }
 839
 840 static int init_udevd_socket(void)
 841 {
 842         struct sockaddr_un saddr;
 843         socklen_t addrlen;
 844         const int feature_on = 1;
 845         int retval;
 846
 847         memset(&saddr, 0x00, sizeof(saddr));
 848         saddr.sun_family = AF_LOCAL;
 849         /* use abstract namespace for socket path */
 850         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 851         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 852
 853         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 854         if (udevd_sock == -1) {
 855                 err("error getting socket: %s", strerror(errno));
 856                 return -1;
 857         }
 858
 859         /* the bind takes care of ensuring only one copy running */
 860         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 861         if (retval < 0) {
 862                 err("bind failed: %s", strerror(errno));
 863                 close(udevd_sock);
 864                 udevd_sock = -1;
 865                 return -1;
 866         }
 867
 868         /* enable receiving of the sender credentials */
 869         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 870
 871         return 0;
 872 }
 873
 874 static int init_uevent_netlink_sock(void)
 875 {
 876         struct sockaddr_nl snl;
 877         const int buffersize = 16 * 1024 * 1024;
 878         int retval;
 879
 880         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 881         snl.nl_family = AF_NETLINK;
 882         snl.nl_pid = getpid();
 883         snl.nl_groups = 1;
 884
 885         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 886         if (uevent_netlink_sock == -1) {
 887                 err("error getting socket: %s", strerror(errno));
 888                 return -1;
 889         }
 890
 891         /* set receive buffersize */
 892         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 893
 894         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 895         if (retval < 0) {
 896                 err("bind failed: %s", strerror(errno));
 897                 close(uevent_netlink_sock);
 898                 uevent_netlink_sock = -1;
 899                 return -1;
 900         }
 901         return 0;
 902 }
 903
 904 static void export_initial_seqnum(void)
 905 {
 906         char filename[PATH_SIZE];
 907         int fd;
 908         char seqnum[32];
 909         ssize_t len = 0;
 910
 911         strlcpy(filename, sysfs_path, sizeof(filename));
 912         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 913         fd = open(filename, O_RDONLY);
 914         if (fd >= 0) {
 915                 len = read(fd, seqnum, sizeof(seqnum)-1);
 916                 close(fd);
 917         }
 918         if (len <= 0) {
 919                 strcpy(seqnum, "0\n");
 920                 len = 3;
 921         }
 922         strlcpy(filename, udev_root, sizeof(filename));
 923         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 924         create_path(filename);
 925         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 926         if (fd >= 0) {
 927                 write(fd, seqnum, len);
 928                 close(fd);
 929         }
 930 }
 931
 932 int main(int argc, char *argv[], char *envp[])
 933 {
 934         int retval;
 935         int fd;
 936         struct sigaction act;
 937         fd_set readfds;
 938         const char *value;
 939         int daemonize = 0;
 940         int option;
 941         static const struct option options[] = {
 942                 { "daemon", 0, NULL, 'd' },
 943                 { "debug-trace", 0, NULL, 't' },
 944                 { "verbose", 0, NULL, 'v' },
 945                 { "help", 0, NULL, 'h' },
 946                 { "version", 0, NULL, 'V' },
 947                 {}
 948         };
 949         int rc = 1;
 950         int maxfd;
 951
 952         logging_init("udevd");
 953         udev_config_init();
 954         selinux_init();
 955         dbg("version %s", UDEV_VERSION);
 956
 957         /* parse commandline options */
 958         while (1) {
 959                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 960                 if (option == -1)
 961                         break;
 962
 963                 switch (option) {
 964                 case 'd':
 965                         daemonize = 1;
 966                         break;
 967                 case 't':
 968                         debug_trace = 1;
 969                         break;
 970                 case 'v':
 971                         verbose = 1;
 972                         if (udev_log_priority < LOG_INFO)
 973                                 udev_log_priority = LOG_INFO;
 974                         break;
 975                 case 'h':
 976                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 977                         goto exit;
 978                 case 'V':
 979                         printf("%s\n", UDEV_VERSION);
 980                         goto exit;
 981                 default:
 982                         goto exit;
 983                 }
 984         }
 985
 986         if (getuid() != 0) {
 987                 fprintf(stderr, "root privileges required\n");
 988                 err("root privileges required");
 989                 goto exit;
 990         }
 991
 992         /* make sure std{in,out,err} fd's are in a sane state */
 993         fd = open("/dev/null", O_RDWR);
 994         if (fd < 0) {
 995                 fprintf(stderr, "cannot open /dev/null\n");
 996                 err("cannot open /dev/null");
 997         }
 998         if (fd > STDIN_FILENO)
 999                 dup2(fd, STDIN_FILENO);
1000         if (write(STDOUT_FILENO, 0, 0) < 0)
1001                 dup2(fd, STDOUT_FILENO);
1002         if (write(STDERR_FILENO, 0, 0) < 0)
1003                 dup2(fd, STDERR_FILENO);
1004
1005         /* init sockets to receive events */
1006         if (init_udevd_socket() < 0) {
1007                 if (errno == EADDRINUSE) {
1008                         fprintf(stderr, "another udev daemon already running\n");
1009                         err("another udev daemon already running");
1010                         rc = 1;
1011                 } else {
1012                         fprintf(stderr, "error initializing udevd socket\n");
1013                         err("error initializing udevd socket");
1014                         rc = 2;
1015                 }
1016                 goto exit;
1017         }
1018
1019         if (init_uevent_netlink_sock() < 0) {
1020                 fprintf(stderr, "error initializing netlink socket\n");
1021                 err("error initializing netlink socket");
1022                 rc = 3;
1023                 goto exit;
1024         }
1025
1026         /* setup signal handler pipe */
1027         retval = pipe(signal_pipe);
1028         if (retval < 0) {
1029                 err("error getting pipes: %s", strerror(errno));
1030                 goto exit;
1031         }
1032
1033         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1034         if (retval < 0) {
1035                 err("error fcntl on read pipe: %s", strerror(errno));
1036                 goto exit;
1037         }
1038         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1039         if (retval < 0) {
1040                 err("error fcntl on read pipe: %s", strerror(errno));
1041                 goto exit;
1042         }
1043
1044         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1045         if (retval < 0) {
1046                 err("error fcntl on write pipe: %s", strerror(errno));
1047                 goto exit;
1048         }
1049         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1050         if (retval < 0) {
1051                 err("error fcntl on write pipe: %s", strerror(errno));
1052                 goto exit;
1053         }
1054
1055         /* parse the rules and keep them in memory */
1056         sysfs_init();
1057         udev_rules_init(&rules, 1);
1058
1059         export_initial_seqnum();
1060
1061         if (daemonize) {
1062                 pid_t pid;
1063
1064                 pid = fork();
1065                 switch (pid) {
1066                 case 0:
1067                         dbg("daemonized fork running");
1068                         break;
1069                 case -1:
1070                         err("fork of daemon failed: %s", strerror(errno));
1071                         rc = 4;
1072                         goto exit;
1073                 default:
1074                         dbg("child [%u] running, parent exits", pid);
1075                         rc = 0;
1076                         goto exit;
1077                 }
1078         }
1079
1080         /* redirect std{out,err} fd's */
1081         if (!verbose)
1082                 dup2(fd, STDOUT_FILENO);
1083         dup2(fd, STDERR_FILENO);
1084         if (fd > STDERR_FILENO)
1085                 close(fd);
1086
1087         /* set scheduling priority for the daemon */
1088         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1089
1090         chdir("/");
1091         umask(022);
1092
1093         /* become session leader */
1094         sid = setsid();
1095         dbg("our session is %d", sid);
1096
1097         /* OOM_DISABLE == -17 */
1098         fd = open("/proc/self/oom_adj", O_RDWR);
1099         if (fd < 0)
1100                 err("error disabling OOM: %s", strerror(errno));
1101         else {
1102                 write(fd, "-17", 3);
1103                 close(fd);
1104         }
1105
1106         /* set signal handlers */
1107         memset(&act, 0x00, sizeof(struct sigaction));
1108         act.sa_handler = (void (*)(int)) sig_handler;
1109         sigemptyset(&act.sa_mask);
1110         act.sa_flags = SA_RESTART;
1111         sigaction(SIGINT, &act, NULL);
1112         sigaction(SIGTERM, &act, NULL);
1113         sigaction(SIGCHLD, &act, NULL);
1114         sigaction(SIGHUP, &act, NULL);
1115
1116         /* watch rules directory */
1117         inotify_fd = inotify_init();
1118         if (inotify_fd >= 0)
1119                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1120         else if (errno == ENOSYS)
1121                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1122         else
1123                 err("inotify_init failed: %s", strerror(errno));
1124
1125         /* maximum limit of forked childs */
1126         value = getenv("UDEVD_MAX_CHILDS");
1127         if (value)
1128                 max_childs = strtoul(value, NULL, 10);
1129         else {
1130                 int memsize = mem_size_mb();
1131                 if (memsize > 0)
1132                         max_childs = 128 + (memsize / 4);
1133                 else
1134                         max_childs = UDEVD_MAX_CHILDS;
1135         }
1136         info("initialize max_childs to %u", max_childs);
1137
1138         /* start to throttle forking if maximum number of _running_ childs is reached */
1139         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1140         if (value)
1141                 max_childs_running = strtoull(value, NULL, 10);
1142         else {
1143                 int cpus = cpu_count();
1144                 if (cpus > 0)
1145                         max_childs_running = 8 + (8 * cpus);
1146                 else
1147                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1148         }
1149         info("initialize max_childs_running to %u", max_childs_running);
1150
1151         /* clear environment for forked event processes */
1152         clearenv();
1153
1154         /* export log_priority , as called programs may want to follow that setting */
1155         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1156         putenv(udev_log);
1157         if (debug_trace)
1158                 putenv("DEBUG=1");
1159
1160         maxfd = udevd_sock;
1161         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1162         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1163         maxfd = UDEV_MAX(maxfd, inotify_fd);
1164
1165         while (!udev_exit) {
1166                 struct udevd_uevent_msg *msg;
1167                 int fdcount;
1168
1169                 FD_ZERO(&readfds);
1170                 FD_SET(signal_pipe[READ_END], &readfds);
1171                 FD_SET(udevd_sock, &readfds);
1172                 FD_SET(uevent_netlink_sock, &readfds);
1173                 if (inotify_fd >= 0)
1174                         FD_SET(inotify_fd, &readfds);
1175
1176                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1177                 if (fdcount < 0) {
1178                         if (errno != EINTR)
1179                                 err("error in select: %s", strerror(errno));
1180                         continue;
1181                 }
1182
1183                 /* get control message */
1184                 if (FD_ISSET(udevd_sock, &readfds))
1185                         get_ctrl_msg();
1186
1187                 /* get netlink message */
1188                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1189                         msg = get_netlink_msg();
1190                         if (msg)
1191                                 msg_queue_insert(msg);
1192                 }
1193
1194                 /* received a signal, clear our notification pipe */
1195                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1196                         char buf[256];
1197
1198                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1199                 }
1200
1201                 /* rules directory inotify watch */
1202                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1203                         int nbytes;
1204
1205                         /* discard all possible events, we can just reload the config */
1206                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1207                                 char *buf;
1208
1209                                 reload_config = 1;
1210                                 buf = malloc(nbytes);
1211                                 if (!buf) {
1212                                         err("error getting buffer for inotify, disable watching");
1213                                         close(inotify_fd);
1214                                         inotify_fd = -1;
1215                                 }
1216                                 read(inotify_fd, buf, nbytes);
1217                                 free(buf);
1218                         }
1219                 }
1220
1221                 /* rules changed, set by inotify or a HUP signal */
1222                 if (reload_config) {
1223                         reload_config = 0;
1224                         udev_rules_cleanup(&rules);
1225                         udev_rules_init(&rules, 1);
1226                 }
1227
1228                 /* forked child has returned */
1229                 if (sigchilds_waiting) {
1230                         sigchilds_waiting = 0;
1231                         reap_sigchilds();
1232                 }
1233
1234                 if (run_exec_q) {
1235                         run_exec_q = 0;
1236                         if (!stop_exec_q)
1237                                 msg_queue_manager();
1238                 }
1239         }
1240         rc = 0;
1241
1242 exit:
1243         udev_rules_cleanup(&rules);
1244         sysfs_cleanup();
1245
1246         if (signal_pipe[READ_END] >= 0)
1247                 close(signal_pipe[READ_END]);
1248         if (signal_pipe[WRITE_END] >= 0)
1249                 close(signal_pipe[WRITE_END]);
1250
1251         if (udevd_sock >= 0)
1252                 close(udevd_sock);
1253         if (inotify_fd >= 0)
1254                 close(inotify_fd);
1255         if (uevent_netlink_sock >= 0)
1256                 close(uevent_netlink_sock);
1257
1258         logging_close();
1259
1260         return rc;
1261 }