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 <sys/select.h>
  33 #include <sys/wait.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <sys/un.h>
  37 #include <sys/stat.h>
  38 #include <sys/ioctl.h>
  39 #include <linux/types.h>
  40 #include <linux/netlink.h>
  41
  42 #include "udev.h"
  43 #include "udev_rules.h"
  44 #include "udevd.h"
  45 #include "udev_selinux.h"
  46
  47 static struct udev_rules rules;
  48 static int udevd_sock = -1;
  49 static int uevent_netlink_sock = -1;
  50 static int inotify_fd = -1;
  51 static pid_t sid;
  52
  53 static int signal_pipe[2] = {-1, -1};
  54 static volatile int sigchilds_waiting;
  55 static volatile int udev_exit;
  56 static volatile int reload_config;
  57 static int run_exec_q;
  58 static int stop_exec_q;
  59 static int max_childs;
  60 static int max_childs_running;
  61 static char udev_log[32];
  62
  63 static LIST_HEAD(exec_list);
  64 static LIST_HEAD(running_list);
  65
  66
  67 #ifdef USE_LOG
  68 void log_message(int priority, const char *format, ...)
  69 {
  70         va_list args;
  71
  72         if (priority > udev_log_priority)
  73                 return;
  74
  75         va_start(args, format);
  76         vsyslog(priority, format, args);
  77         va_end(args);
  78 }
  79 #endif
  80
  81 static void asmlinkage udev_event_sig_handler(int signum)
  82 {
  83         if (signum == SIGALRM)
  84                 exit(1);
  85 }
  86
  87 static int udev_event_process(struct udevd_uevent_msg *msg)
  88 {
  89         struct sigaction act;
  90         struct udevice *udev;
  91         int i;
  92         int retval;
  93
  94         /* set signal handlers */
  95         memset(&act, 0x00, sizeof(act));
  96         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  97         sigemptyset (&act.sa_mask);
  98         act.sa_flags = 0;
  99         sigaction(SIGALRM, &act, NULL);
 100
 101         /* reset to default */
 102         act.sa_handler = SIG_DFL;
 103         sigaction(SIGINT, &act, NULL);
 104         sigaction(SIGTERM, &act, NULL);
 105         sigaction(SIGCHLD, &act, NULL);
 106         sigaction(SIGHUP, &act, NULL);
 107
 108         /* trigger timeout to prevent hanging processes */
 109         alarm(UDEV_ALARM_TIMEOUT);
 110
 111         /* reconstruct event environment from message */
 112         for (i = 0; msg->envp[i]; i++)
 113                 putenv(msg->envp[i]);
 114
 115         udev = udev_device_init();
 116         if (udev == NULL)
 117                 return -1;
 118         strlcpy(udev->action, msg->action, sizeof(udev->action));
 119         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 120         udev->devt = msg->devt;
 121
 122         retval = udev_device_event(&rules, udev);
 123
 124         /* run programs collected by RUN-key*/
 125         if (retval == 0 && !udev->ignore_device && udev_run) {
 126                 struct name_entry *name_loop;
 127
 128                 dbg("executing run list");
 129                 list_for_each_entry(name_loop, &udev->run_list, node) {
 130                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 131                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 132                         else {
 133                                 char program[PATH_SIZE];
 134
 135                                 strlcpy(program, name_loop->name, sizeof(program));
 136                                 udev_rules_apply_format(udev, program, sizeof(program));
 137                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 138                                                 (udev_log_priority >= LOG_INFO)))
 139                                         retval = -1;
 140                         }
 141                 }
 142         }
 143
 144         udev_device_cleanup(udev);
 145         return retval;
 146 }
 147
 148 enum event_state {
 149         EVENT_QUEUED,
 150         EVENT_FINISHED,
 151         EVENT_FAILED,
 152 };
 153
 154 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 155 {
 156         char filename[PATH_SIZE];
 157         char filename_failed[PATH_SIZE];
 158         size_t start, end, i;
 159         struct udevd_uevent_msg *loop_msg;
 160         int fd;
 161
 162         /* add location of queue files */
 163         strlcpy(filename, udev_root, sizeof(filename));
 164         strlcat(filename, "/", sizeof(filename));
 165         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 166         end = strlcat(filename, msg->devpath, sizeof(filename));
 167         if (end > sizeof(filename))
 168                 end = sizeof(filename);
 169
 170         /* replace '/' to transform path into a filename */
 171         for (i = start+1; i < end; i++)
 172                 if (filename[i] == '/')
 173                         filename[i] = PATH_TO_NAME_CHAR;
 174
 175         /* add location of failed files */
 176         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 177         strlcat(filename_failed, "/", sizeof(filename_failed));
 178         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 179         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 180         if (end > sizeof(filename_failed))
 181                 end = sizeof(filename_failed);
 182
 183         /* replace '/' to transform path into a filename */
 184         for (i = start+1; i < end; i++)
 185                 if (filename_failed[i] == '/')
 186                         filename_failed[i] = PATH_TO_NAME_CHAR;
 187
 188         switch (state) {
 189         case EVENT_QUEUED:
 190                 unlink(filename_failed);
 191                 delete_path(filename_failed);
 192                 create_path(filename);
 193                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 194                 if (fd > 0)
 195                         close(fd);
 196                 return;
 197         case EVENT_FINISHED:
 198         case EVENT_FAILED:
 199                 unlink(filename_failed);
 200                 delete_path(filename_failed);
 201
 202                 /* don't remove, if events for the same path are still pending */
 203                 list_for_each_entry(loop_msg, &running_list, node)
 204                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 205                                 return;
 206
 207                 list_for_each_entry(loop_msg, &exec_list, node)
 208                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 209                                 return;
 210
 211                 /* move failed events to the failed directory */
 212                 if (state == EVENT_FAILED) {
 213                         create_path(filename_failed);
 214                         rename(filename, filename_failed);
 215                 } else {
 216                         unlink(filename);
 217                 }
 218
 219                 /* clean up the queue directory */
 220                 delete_path(filename);
 221
 222                 return;
 223         }
 224 }
 225
 226 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 227 {
 228         list_del(&msg->node);
 229
 230         /* mark as failed, if add event returns non-zero */
 231         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 232                 export_event_state(msg, EVENT_FAILED);
 233         else
 234                 export_event_state(msg, EVENT_FINISHED);
 235
 236         free(msg);
 237 }
 238
 239 static void udev_event_run(struct udevd_uevent_msg *msg)
 240 {
 241         pid_t pid;
 242         int retval;
 243
 244         pid = fork();
 245         switch (pid) {
 246         case 0:
 247                 /* child */
 248                 close(uevent_netlink_sock);
 249                 close(udevd_sock);
 250                 if (inotify_fd >= 0)
 251                         close(inotify_fd);
 252                 close(signal_pipe[READ_END]);
 253                 close(signal_pipe[WRITE_END]);
 254                 logging_close();
 255
 256                 logging_init("udevd-event");
 257                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 258
 259                 retval = udev_event_process(msg);
 260                 info("seq %llu finished", msg->seqnum);
 261
 262                 logging_close();
 263                 if (retval)
 264                         exit(1);
 265                 exit(0);
 266         case -1:
 267                 err("fork of child failed: %s", strerror(errno));
 268                 msg_queue_delete(msg);
 269                 break;
 270         default:
 271                 /* get SIGCHLD in main loop */
 272                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 273                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 274                 msg->pid = pid;
 275         }
 276 }
 277
 278 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 279 {
 280         char filename[PATH_SIZE];
 281         int fd;
 282
 283         msg->queue_time = time(NULL);
 284
 285         strlcpy(filename, udev_root, sizeof(filename));
 286         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 287         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 288         if (fd >= 0) {
 289                 char str[32];
 290                 int len;
 291
 292                 len = sprintf(str, "%llu\n", msg->seqnum);
 293                 write(fd, str, len);
 294                 close(fd);
 295         }
 296
 297         export_event_state(msg, EVENT_QUEUED);
 298
 299         /* run all events with a timeout set immediately */
 300         if (msg->timeout != 0) {
 301                 list_add_tail(&msg->node, &running_list);
 302                 udev_event_run(msg);
 303                 return;
 304         }
 305
 306         list_add_tail(&msg->node, &exec_list);
 307         run_exec_q = 1;
 308 }
 309
 310 static int mem_size_mb(void)
 311 {
 312         int f;
 313         char buf[8192];
 314         long int len;
 315         const char *pos;
 316         long int memsize;
 317
 318         f = open("/proc/meminfo", O_RDONLY);
 319         if (f == -1)
 320                 return -1;
 321
 322         len = read(f, buf, sizeof(buf)-1);
 323         close(f);
 324
 325         if (len <= 0)
 326                 return -1;
 327         buf[len] = '\0';
 328
 329         pos = strstr(buf, "MemTotal: ");
 330         if (pos == NULL)
 331                 return -1;
 332
 333         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 334                 return -1;
 335
 336         return memsize / 1024;
 337 }
 338
 339 static int cpu_count(void)
 340 {
 341         int f;
 342         char buf[32768];
 343         int len;
 344         const char *pos;
 345         int count = 0;
 346
 347         f = open("/proc/stat", O_RDONLY);
 348         if (f == -1)
 349                 return -1;
 350
 351         len = read(f, buf, sizeof(buf)-1);
 352         close(f);
 353         if (len <= 0)
 354                 return -1;
 355         buf[len] = '\0';
 356
 357         pos = strstr(buf, "cpu");
 358         if (pos == NULL)
 359                 return -1;
 360
 361         while (pos != NULL) {
 362                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 363                         count++;
 364                 pos = strstr(&pos[3], "cpu");
 365         }
 366
 367         if (count == 0)
 368                 return -1;
 369         return count;
 370 }
 371
 372 static int running_processes(void)
 373 {
 374         int f;
 375         char buf[32768];
 376         int len;
 377         int running;
 378         const char *pos;
 379
 380         f = open("/proc/stat", O_RDONLY);
 381         if (f == -1)
 382                 return -1;
 383
 384         len = read(f, buf, sizeof(buf)-1);
 385         close(f);
 386         if (len <= 0)
 387                 return -1;
 388         buf[len] = '\0';
 389
 390         pos = strstr(buf, "procs_running ");
 391         if (pos == NULL)
 392                 return -1;
 393
 394         if (sscanf(pos, "procs_running %u", &running) != 1)
 395                 return -1;
 396
 397         return running;
 398 }
 399
 400 /* return the number of process es in our session, count only until limit */
 401 static int running_processes_in_session(pid_t session, int limit)
 402 {
 403         DIR *dir;
 404         struct dirent *dent;
 405         int running = 0;
 406
 407         dir = opendir("/proc");
 408         if (!dir)
 409                 return -1;
 410
 411         /* read process info from /proc */
 412         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 413                 int f;
 414                 char procdir[64];
 415                 char line[256];
 416                 const char *pos;
 417                 char state;
 418                 pid_t ppid, pgrp, sess;
 419                 int len;
 420
 421                 if (!isdigit(dent->d_name[0]))
 422                         continue;
 423
 424                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 425                 procdir[sizeof(procdir)-1] = '\0';
 426
 427                 f = open(procdir, O_RDONLY);
 428                 if (f == -1)
 429                         continue;
 430
 431                 len = read(f, line, sizeof(line)-1);
 432                 close(f);
 433
 434                 if (len <= 0)
 435                         continue;
 436                 else
 437                         line[len] = '\0';
 438
 439                 /* skip ugly program name */
 440                 pos = strrchr(line, ')') + 2;
 441                 if (pos == NULL)
 442                         continue;
 443
 444                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 445                         continue;
 446
 447                 /* count only processes in our session */
 448                 if (sess != session)
 449                         continue;
 450
 451                 /* count only running, no sleeping processes */
 452                 if (state != 'R')
 453                         continue;
 454
 455                 running++;
 456                 if (limit > 0 && running >= limit)
 457                         break;
 458         }
 459         closedir(dir);
 460
 461         return running;
 462 }
 463
 464 static int compare_devpath(const char *running, const char *waiting)
 465 {
 466         int i;
 467
 468         for (i = 0; i < PATH_SIZE; i++) {
 469                 /* identical device event found */
 470                 if (running[i] == '\0' && waiting[i] == '\0')
 471                         return 1;
 472
 473                 /* parent device event found */
 474                 if (running[i] == '\0' && waiting[i] == '/')
 475                         return 2;
 476
 477                 /* child device event found */
 478                 if (running[i] == '/' && waiting[i] == '\0')
 479                         return 3;
 480
 481                 /* no matching event */
 482                 if (running[i] != waiting[i])
 483                         break;
 484         }
 485
 486         return 0;
 487 }
 488
 489 /* returns still running task for the same device, its parent or its physical device */
 490 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 491 {
 492         struct udevd_uevent_msg *loop_msg;
 493         int childs_count = 0;
 494
 495         list_for_each_entry(loop_msg, &running_list, node) {
 496                 if (limit && childs_count++ > limit) {
 497                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 498                         return 1;
 499                 }
 500
 501                 /* return running parent/child device event */
 502                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 503                         dbg("%llu, child device event still running %llu (%s)",
 504                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 505                         return 2;
 506                 }
 507
 508                 /* return running physical device event */
 509                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 510                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 511                                 dbg("%llu, physical device event still running %llu (%s)",
 512                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 513                                 return 3;
 514                         }
 515         }
 516
 517         return 0;
 518 }
 519
 520 /* exec queue management routine executes the events and serializes events in the same sequence */
 521 static void msg_queue_manager(void)
 522 {
 523         struct udevd_uevent_msg *loop_msg;
 524         struct udevd_uevent_msg *tmp_msg;
 525         int running;
 526
 527         if (list_empty(&exec_list))
 528                 return;
 529
 530         running = running_processes();
 531         dbg("%d processes runnning on system", running);
 532         if (running < 0)
 533                 running = max_childs_running;
 534
 535         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 536                 /* check running processes in our session and possibly throttle */
 537                 if (running >= max_childs_running) {
 538                         running = running_processes_in_session(sid, max_childs_running+10);
 539                         dbg("at least %d processes running in session", running);
 540                         if (running >= max_childs_running) {
 541                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 542                                 return;
 543                         }
 544                 }
 545
 546                 /* don't run two processes for the same devpath and wait for the parent*/
 547                 if (running_with_devpath(loop_msg, max_childs)) {
 548                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 549                         continue;
 550                 }
 551
 552                 /* move event to run list */
 553                 list_move_tail(&loop_msg->node, &running_list);
 554                 udev_event_run(loop_msg);
 555                 running++;
 556                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 557         }
 558 }
 559
 560 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 561 {
 562         int bufpos;
 563         int i;
 564         struct udevd_uevent_msg *msg;
 565         char *physdevdriver_key = NULL;
 566         int maj = 0;
 567         int min = 0;
 568
 569         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 570         if (msg == NULL)
 571                 return NULL;
 572         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 573
 574         /* copy environment buffer and reconstruct envp */
 575         memcpy(msg->envbuf, buf, buf_size);
 576         bufpos = 0;
 577         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 578                 int keylen;
 579                 char *key;
 580
 581                 key = &msg->envbuf[bufpos];
 582                 keylen = strlen(key);
 583                 msg->envp[i] = key;
 584                 bufpos += keylen + 1;
 585                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 586
 587                 /* remember some keys for further processing */
 588                 if (strncmp(key, "ACTION=", 7) == 0)
 589                         msg->action = &key[7];
 590                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 591                         msg->devpath = &key[8];
 592                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 593                         msg->subsystem = &key[10];
 594                 else if (strncmp(key, "DRIVER=", 7) == 0)
 595                         msg->driver = &key[7];
 596                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 597                         msg->seqnum = strtoull(&key[7], NULL, 10);
 598                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 599                         msg->physdevpath = &key[12];
 600                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 601                         physdevdriver_key = key;
 602                 else if (strncmp(key, "MAJOR=", 6) == 0)
 603                         maj = strtoull(&key[6], NULL, 10);
 604                 else if (strncmp(key, "MINOR=", 6) == 0)
 605                         min = strtoull(&key[6], NULL, 10);
 606                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 607                         msg->timeout = strtoull(&key[8], NULL, 10);
 608         }
 609         msg->devt = makedev(maj, min);
 610         msg->envp[i++] = "UDEVD_EVENT=1";
 611
 612         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 613                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 614                 msg->envp[i++] = &physdevdriver_key[7];
 615                 msg->driver = &physdevdriver_key[14];
 616         }
 617
 618         msg->envp[i] = NULL;
 619
 620         if (msg->devpath == NULL || msg->action == NULL) {
 621                 info("DEVPATH or ACTION missing, ignore message");
 622                 free(msg);
 623                 return NULL;
 624         }
 625         return msg;
 626 }
 627
 628 /* receive the udevd message from userspace */
 629 static void get_ctrl_msg(void)
 630 {
 631         struct udevd_ctrl_msg ctrl_msg;
 632         ssize_t size;
 633         struct msghdr smsg;
 634         struct cmsghdr *cmsg;
 635         struct iovec iov;
 636         struct ucred *cred;
 637         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 638         int *intval;
 639
 640         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 641         iov.iov_base = &ctrl_msg;
 642         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 643
 644         memset(&smsg, 0x00, sizeof(struct msghdr));
 645         smsg.msg_iov = &iov;
 646         smsg.msg_iovlen = 1;
 647         smsg.msg_control = cred_msg;
 648         smsg.msg_controllen = sizeof(cred_msg);
 649
 650         size = recvmsg(udevd_sock, &smsg, 0);
 651         if (size <  0) {
 652                 if (errno != EINTR)
 653                         err("unable to receive user udevd message: %s", strerror(errno));
 654                 return;
 655         }
 656         cmsg = CMSG_FIRSTHDR(&smsg);
 657         cred = (struct ucred *) CMSG_DATA(cmsg);
 658
 659         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 660                 err("no sender credentials received, message ignored");
 661                 return;
 662         }
 663
 664         if (cred->uid != 0) {
 665                 err("sender uid=%i, message ignored", cred->uid);
 666                 return;
 667         }
 668
 669         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 670                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 671                 return;
 672         }
 673
 674         switch (ctrl_msg.type) {
 675         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 676                 info("udevd message (STOP_EXEC_QUEUE) received");
 677                 stop_exec_q = 1;
 678                 break;
 679         case UDEVD_CTRL_START_EXEC_QUEUE:
 680                 info("udevd message (START_EXEC_QUEUE) received");
 681                 stop_exec_q = 0;
 682                 msg_queue_manager();
 683                 break;
 684         case UDEVD_CTRL_SET_LOG_LEVEL:
 685                 intval = (int *) ctrl_msg.buf;
 686                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 687                 udev_log_priority = *intval;
 688                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 689                 putenv(udev_log);
 690                 break;
 691         case UDEVD_CTRL_SET_MAX_CHILDS:
 692                 intval = (int *) ctrl_msg.buf;
 693                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 694                 max_childs = *intval;
 695                 break;
 696         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 697                 intval = (int *) ctrl_msg.buf;
 698                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 699                 max_childs_running = *intval;
 700                 break;
 701         case UDEVD_CTRL_RELOAD_RULES:
 702                 info("udevd message (RELOAD_RULES) received");
 703                 reload_config = 1;
 704                 break;
 705         default:
 706                 err("unknown control message type");
 707         }
 708 }
 709
 710 /* receive the kernel user event message and do some sanity checks */
 711 static struct udevd_uevent_msg *get_netlink_msg(void)
 712 {
 713         struct udevd_uevent_msg *msg;
 714         int bufpos;
 715         ssize_t size;
 716         static char buffer[UEVENT_BUFFER_SIZE+512];
 717         char *pos;
 718
 719         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 720         if (size <  0) {
 721                 if (errno != EINTR)
 722                         err("unable to receive kernel netlink message: %s", strerror(errno));
 723                 return NULL;
 724         }
 725
 726         if ((size_t)size > sizeof(buffer)-1)
 727                 size = sizeof(buffer)-1;
 728         buffer[size] = '\0';
 729         dbg("uevent_size=%zi", size);
 730
 731         /* start of event payload */
 732         bufpos = strlen(buffer)+1;
 733         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 734         if (msg == NULL)
 735                 return NULL;
 736
 737         /* validate message */
 738         pos = strchr(buffer, '@');
 739         if (pos == NULL) {
 740                 err("invalid uevent '%s'", buffer);
 741                 free(msg);
 742                 return NULL;
 743         }
 744         pos[0] = '\0';
 745
 746         if (msg->action == NULL) {
 747                 info("no ACTION in payload found, skip event '%s'", buffer);
 748                 free(msg);
 749                 return NULL;
 750         }
 751
 752         if (strcmp(msg->action, buffer) != 0) {
 753                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 754                 free(msg);
 755                 return NULL;
 756         }
 757
 758         return msg;
 759 }
 760
 761 static void asmlinkage sig_handler(int signum)
 762 {
 763         switch (signum) {
 764                 case SIGINT:
 765                 case SIGTERM:
 766                         udev_exit = 1;
 767                         break;
 768                 case SIGCHLD:
 769                         /* set flag, then write to pipe if needed */
 770                         sigchilds_waiting = 1;
 771                         break;
 772                 case SIGHUP:
 773                         reload_config = 1;
 774                         break;
 775         }
 776
 777         /* write to pipe, which will wakeup select() in our mainloop */
 778         write(signal_pipe[WRITE_END], "", 1);
 779 }
 780
 781 static void udev_done(int pid, int exitstatus)
 782 {
 783         /* find msg associated with pid and delete it */
 784         struct udevd_uevent_msg *msg;
 785
 786         list_for_each_entry(msg, &running_list, node) {
 787                 if (msg->pid == pid) {
 788                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 789                              exitstatus, time(NULL) - msg->queue_time);
 790                         msg->exitstatus = exitstatus;
 791                         msg_queue_delete(msg);
 792
 793                         /* there may be events waiting with the same devpath */
 794                         run_exec_q = 1;
 795                         return;
 796                 }
 797         }
 798 }
 799
 800 static void reap_sigchilds(void)
 801 {
 802         pid_t pid;
 803         int status;
 804
 805         while (1) {
 806                 pid = waitpid(-1, &status, WNOHANG);
 807                 if (pid <= 0)
 808                         break;
 809                 if (WIFEXITED(status))
 810                         status = WEXITSTATUS(status);
 811                 else if (WIFSIGNALED(status))
 812                         status = WTERMSIG(status) + 128;
 813                 else
 814                         status = 0;
 815                 udev_done(pid, status);
 816         }
 817 }
 818
 819 static int init_udevd_socket(void)
 820 {
 821         struct sockaddr_un saddr;
 822         socklen_t addrlen;
 823         const int feature_on = 1;
 824         int retval;
 825
 826         memset(&saddr, 0x00, sizeof(saddr));
 827         saddr.sun_family = AF_LOCAL;
 828         /* use abstract namespace for socket path */
 829         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 830         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 831
 832         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 833         if (udevd_sock == -1) {
 834                 err("error getting socket: %s", strerror(errno));
 835                 return -1;
 836         }
 837
 838         /* the bind takes care of ensuring only one copy running */
 839         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 840         if (retval < 0) {
 841                 err("bind failed: %s", strerror(errno));
 842                 close(udevd_sock);
 843                 udevd_sock = -1;
 844                 return -1;
 845         }
 846
 847         /* enable receiving of the sender credentials */
 848         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 849
 850         return 0;
 851 }
 852
 853 static int init_uevent_netlink_sock(void)
 854 {
 855         struct sockaddr_nl snl;
 856         const int buffersize = 16 * 1024 * 1024;
 857         int retval;
 858
 859         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 860         snl.nl_family = AF_NETLINK;
 861         snl.nl_pid = getpid();
 862         snl.nl_groups = 1;
 863
 864         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 865         if (uevent_netlink_sock == -1) {
 866                 err("error getting socket: %s", strerror(errno));
 867                 return -1;
 868         }
 869
 870         /* set receive buffersize */
 871         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 872
 873         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 874         if (retval < 0) {
 875                 err("bind failed: %s", strerror(errno));
 876                 close(uevent_netlink_sock);
 877                 uevent_netlink_sock = -1;
 878                 return -1;
 879         }
 880         return 0;
 881 }
 882
 883 static void export_initial_seqnum(void)
 884 {
 885         char filename[PATH_SIZE];
 886         int fd;
 887         char seqnum[32];
 888         ssize_t len = 0;
 889
 890         strlcpy(filename, sysfs_path, sizeof(filename));
 891         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 892         fd = open(filename, O_RDONLY);
 893         if (fd >= 0) {
 894                 len = read(fd, seqnum, sizeof(seqnum)-1);
 895                 close(fd);
 896         }
 897         if (len <= 0) {
 898                 strcpy(seqnum, "0\n");
 899                 len = 3;
 900         }
 901         strlcpy(filename, udev_root, sizeof(filename));
 902         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 903         create_path(filename);
 904         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 905         if (fd >= 0) {
 906                 write(fd, seqnum, len);
 907                 close(fd);
 908         }
 909 }
 910
 911 int main(int argc, char *argv[], char *envp[])
 912 {
 913         int retval;
 914         int fd;
 915         struct sigaction act;
 916         fd_set readfds;
 917         const char *value;
 918         int daemonize = 0;
 919         int i;
 920         int rc = 1;
 921         int maxfd;
 922
 923         logging_init("udevd");
 924         udev_config_init();
 925         selinux_init();
 926         dbg("version %s", UDEV_VERSION);
 927
 928         /* parse commandline options */
 929         for (i = 1 ; i < argc; i++) {
 930                 char *arg = argv[i];
 931                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0)
 932                         daemonize = 1;
 933                 else if (strcmp(arg, "--help") == 0 || strcmp(arg, "-h") == 0) {
 934                         printf("Usage: udevd [--help] [--daemon]\n");
 935                         goto exit;
 936                 } else {
 937                         fprintf(stderr, "unrecognized option '%s'\n", arg);
 938                         err("unrecognized option '%s'\n", arg);
 939                 }
 940         }
 941
 942         if (getuid() != 0) {
 943                 fprintf(stderr, "root privileges required\n");
 944                 err("root privileges required");
 945                 goto exit;
 946         }
 947
 948         /* init sockets to receive events */
 949         if (init_udevd_socket() < 0) {
 950                 if (errno == EADDRINUSE) {
 951                         fprintf(stderr, "another udev daemon already running\n");
 952                         err("another udev daemon already running");
 953                         rc = 1;
 954                 } else {
 955                         fprintf(stderr, "error initializing udevd socket\n");
 956                         err("error initializing udevd socket");
 957                         rc = 2;
 958                 }
 959                 goto exit;
 960         }
 961
 962         if (init_uevent_netlink_sock() < 0) {
 963                 fprintf(stderr, "error initializing netlink socket\n");
 964                 err("error initializing netlink socket");
 965                 rc = 3;
 966                 goto exit;
 967         }
 968
 969         /* parse the rules and keep them in memory */
 970         sysfs_init();
 971         udev_rules_init(&rules, 1);
 972
 973         export_initial_seqnum();
 974
 975         if (daemonize) {
 976                 pid_t pid;
 977
 978                 pid = fork();
 979                 switch (pid) {
 980                 case 0:
 981                         dbg("daemonized fork running");
 982                         break;
 983                 case -1:
 984                         err("fork of daemon failed: %s", strerror(errno));
 985                         rc = 4;
 986                         goto exit;
 987                 default:
 988                         dbg("child [%u] running, parent exits", pid);
 989                         rc = 0;
 990                         goto exit;
 991                 }
 992         }
 993
 994         /* redirect std fd's */
 995         fd = open("/dev/null", O_RDWR);
 996         if (fd >= 0) {
 997                 dup2(fd, STDIN_FILENO);
 998                 dup2(fd, STDOUT_FILENO);
 999                 dup2(fd, STDERR_FILENO);
1000                 if (fd > STDERR_FILENO)
1001                         close(fd);
1002         } else
1003                 err("error opening /dev/null: %s", strerror(errno));
1004
1005         /* set scheduling priority for the daemon */
1006         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1007
1008         chdir("/");
1009         umask(022);
1010
1011         /* become session leader */
1012         sid = setsid();
1013         dbg("our session is %d", sid);
1014
1015         /* OOM_DISABLE == -17 */
1016         fd = open("/proc/self/oom_adj", O_RDWR);
1017         if (fd < 0)
1018                 err("error disabling OOM: %s", strerror(errno));
1019         else {
1020                 write(fd, "-17", 3);
1021                 close(fd);
1022         }
1023
1024         /* setup signal handler pipe */
1025         retval = pipe(signal_pipe);
1026         if (retval < 0) {
1027                 err("error getting pipes: %s", strerror(errno));
1028                 goto exit;
1029         }
1030
1031         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1032         if (retval < 0) {
1033                 err("error fcntl on read pipe: %s", strerror(errno));
1034                 goto exit;
1035         }
1036         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1037         if (retval < 0) {
1038                 err("error fcntl on read pipe: %s", strerror(errno));
1039                 goto exit;
1040         }
1041
1042         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1043         if (retval < 0) {
1044                 err("error fcntl on write pipe: %s", strerror(errno));
1045                 goto exit;
1046         }
1047         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1048         if (retval < 0) {
1049                 err("error fcntl on write pipe: %s", strerror(errno));
1050                 goto exit;
1051         }
1052
1053         /* set signal handlers */
1054         memset(&act, 0x00, sizeof(struct sigaction));
1055         act.sa_handler = (void (*)(int)) sig_handler;
1056         sigemptyset(&act.sa_mask);
1057         act.sa_flags = SA_RESTART;
1058         sigaction(SIGINT, &act, NULL);
1059         sigaction(SIGTERM, &act, NULL);
1060         sigaction(SIGCHLD, &act, NULL);
1061         sigaction(SIGHUP, &act, NULL);
1062
1063         /* watch rules directory */
1064         inotify_fd = inotify_init();
1065         if (inotify_fd >= 0)
1066                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1067         else if (errno == ENOSYS)
1068                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1069         else
1070                 err("inotify_init failed: %s", strerror(errno));
1071
1072         /* maximum limit of forked childs */
1073         value = getenv("UDEVD_MAX_CHILDS");
1074         if (value)
1075                 max_childs = strtoul(value, NULL, 10);
1076         else {
1077                 int memsize = mem_size_mb();
1078                 if (memsize > 0)
1079                         max_childs = 128 + (memsize / 4);
1080                 else
1081                         max_childs = UDEVD_MAX_CHILDS;
1082         }
1083         info("initialize max_childs to %u", max_childs);
1084
1085         /* start to throttle forking if maximum number of _running_ childs is reached */
1086         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1087         if (value)
1088                 max_childs_running = strtoull(value, NULL, 10);
1089         else {
1090                 int cpus = cpu_count();
1091                 if (cpus > 0)
1092                         max_childs_running = 8 + (8 * cpus);
1093                 else
1094                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1095         }
1096         info("initialize max_childs_running to %u", max_childs_running);
1097
1098         /* clear environment for forked event processes */
1099         clearenv();
1100
1101         /* export log_priority , as called programs may want to follow that setting */
1102         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1103         putenv(udev_log);
1104
1105         maxfd = udevd_sock;
1106         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1107         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1108         maxfd = UDEV_MAX(maxfd, inotify_fd);
1109
1110         while (!udev_exit) {
1111                 struct udevd_uevent_msg *msg;
1112                 int fdcount;
1113
1114                 FD_ZERO(&readfds);
1115                 FD_SET(signal_pipe[READ_END], &readfds);
1116                 FD_SET(udevd_sock, &readfds);
1117                 FD_SET(uevent_netlink_sock, &readfds);
1118                 if (inotify_fd >= 0)
1119                         FD_SET(inotify_fd, &readfds);
1120
1121                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1122                 if (fdcount < 0) {
1123                         if (errno != EINTR)
1124                                 err("error in select: %s", strerror(errno));
1125                         continue;
1126                 }
1127
1128                 /* get control message */
1129                 if (FD_ISSET(udevd_sock, &readfds))
1130                         get_ctrl_msg();
1131
1132                 /* get netlink message */
1133                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1134                         msg = get_netlink_msg();
1135                         if (msg)
1136                                 msg_queue_insert(msg);
1137                 }
1138
1139                 /* received a signal, clear our notification pipe */
1140                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1141                         char buf[256];
1142
1143                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1144                 }
1145
1146                 /* rules directory inotify watch */
1147                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1148                         int nbytes;
1149
1150                         /* discard all possible events, we can just reload the config */
1151                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1152                                 char *buf;
1153
1154                                 reload_config = 1;
1155                                 buf = malloc(nbytes);
1156                                 if (!buf) {
1157                                         err("error getting buffer for inotify, disable watching");
1158                                         close(inotify_fd);
1159                                         inotify_fd = -1;
1160                                 }
1161                                 read(inotify_fd, buf, nbytes);
1162                                 free(buf);
1163                         }
1164                 }
1165
1166                 /* rules changed, set by inotify or a HUP signal */
1167                 if (reload_config) {
1168                         reload_config = 0;
1169                         udev_rules_cleanup(&rules);
1170                         udev_rules_init(&rules, 1);
1171                 }
1172
1173                 /* forked child has returned */
1174                 if (sigchilds_waiting) {
1175                         sigchilds_waiting = 0;
1176                         reap_sigchilds();
1177                 }
1178
1179                 if (run_exec_q) {
1180                         run_exec_q = 0;
1181                         if (!stop_exec_q)
1182                                 msg_queue_manager();
1183                 }
1184         }
1185         rc = 0;
1186
1187 exit:
1188         udev_rules_cleanup(&rules);
1189         sysfs_cleanup();
1190
1191         if (signal_pipe[READ_END] >= 0)
1192                 close(signal_pipe[READ_END]);
1193         if (signal_pipe[WRITE_END] >= 0)
1194                 close(signal_pipe[WRITE_END]);
1195
1196         if (udevd_sock >= 0)
1197                 close(udevd_sock);
1198         if (inotify_fd >= 0)
1199                 close(inotify_fd);
1200         if (uevent_netlink_sock >= 0)
1201                 close(uevent_netlink_sock);
1202
1203         logging_close();
1204
1205         return rc;
1206 }