udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   6  *
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stddef.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <time.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47 #include "udevd.h"
  48 #include "udev_selinux.h"
  49
  50 static struct udev_rules rules;
  51 static int udevd_sock = -1;
  52 static int uevent_netlink_sock = -1;
  53 static int inotify_fd = -1;
  54 static pid_t sid;
  55
  56 static int signal_pipe[2] = {-1, -1};
  57 static volatile int sigchilds_waiting;
  58 static volatile int udev_exit;
  59 static volatile int reload_config;
  60 static int run_exec_q;
  61 static int stop_exec_q;
  62 static int max_childs;
  63 static int max_childs_running;
  64 static char udev_log[32];
  65
  66 static LIST_HEAD(exec_list);
  67 static LIST_HEAD(running_list);
  68
  69
  70 #ifdef USE_LOG
  71 void log_message(int priority, const char *format, ...)
  72 {
  73         va_list args;
  74
  75         if (priority > udev_log_priority)
  76                 return;
  77
  78         va_start(args, format);
  79         vsyslog(priority, format, args);
  80         va_end(args);
  81 }
  82 #endif
  83
  84 static void asmlinkage udev_event_sig_handler(int signum)
  85 {
  86         if (signum == SIGALRM)
  87                 exit(1);
  88 }
  89
  90 static int udev_event_process(struct udevd_uevent_msg *msg)
  91 {
  92         struct sigaction act;
  93         struct udevice *udev;
  94         int i;
  95         int retval;
  96
  97         /* set signal handlers */
  98         memset(&act, 0x00, sizeof(act));
  99         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 100         sigemptyset (&act.sa_mask);
 101         act.sa_flags = 0;
 102         sigaction(SIGALRM, &act, NULL);
 103
 104         /* reset to default */
 105         act.sa_handler = SIG_DFL;
 106         sigaction(SIGINT, &act, NULL);
 107         sigaction(SIGTERM, &act, NULL);
 108         sigaction(SIGCHLD, &act, NULL);
 109         sigaction(SIGHUP, &act, NULL);
 110
 111         /* trigger timeout to prevent hanging processes */
 112         alarm(UDEV_ALARM_TIMEOUT);
 113
 114         /* reconstruct event environment from message */
 115         for (i = 0; msg->envp[i]; i++)
 116                 putenv(msg->envp[i]);
 117
 118         udev = udev_device_init();
 119         if (udev == NULL)
 120                 return -1;
 121         strlcpy(udev->action, msg->action, sizeof(udev->action));
 122         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 123         udev->devt = msg->devt;
 124
 125         retval = udev_device_event(&rules, udev);
 126
 127         /* run programs collected by RUN-key*/
 128         if (retval == 0 && !udev->ignore_device && udev_run) {
 129                 struct name_entry *name_loop;
 130
 131                 dbg("executing run list");
 132                 list_for_each_entry(name_loop, &udev->run_list, node) {
 133                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 134                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 135                         else {
 136                                 char program[PATH_SIZE];
 137
 138                                 strlcpy(program, name_loop->name, sizeof(program));
 139                                 udev_rules_apply_format(udev, program, sizeof(program));
 140                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 141                                                 (udev_log_priority >= LOG_INFO)))
 142                                         retval = -1;
 143                         }
 144                 }
 145         }
 146
 147         udev_device_cleanup(udev);
 148         return retval;
 149 }
 150
 151 enum event_state {
 152         EVENT_QUEUED,
 153         EVENT_FINISHED,
 154         EVENT_FAILED,
 155 };
 156
 157 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 158 {
 159         char filename[PATH_SIZE];
 160         char filename_failed[PATH_SIZE];
 161         char target[PATH_SIZE];
 162         size_t start, end, i;
 163         struct udevd_uevent_msg *loop_msg;
 164
 165         /* add location of queue files */
 166         strlcpy(filename, udev_root, sizeof(filename));
 167         strlcat(filename, "/", sizeof(filename));
 168         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 169         end = strlcat(filename, msg->devpath, sizeof(filename));
 170         if (end > sizeof(filename))
 171                 end = sizeof(filename);
 172
 173         /* replace '/' to transform path into a filename */
 174         for (i = start+1; i < end; i++)
 175                 if (filename[i] == '/')
 176                         filename[i] = PATH_TO_NAME_CHAR;
 177
 178         /* add location of failed files */
 179         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 180         strlcat(filename_failed, "/", sizeof(filename_failed));
 181         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 182         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 183         if (end > sizeof(filename_failed))
 184                 end = sizeof(filename_failed);
 185
 186         /* replace '/' to transform path into a filename */
 187         for (i = start+1; i < end; i++)
 188                 if (filename_failed[i] == '/')
 189                         filename_failed[i] = PATH_TO_NAME_CHAR;
 190
 191         switch (state) {
 192         case EVENT_QUEUED:
 193                 unlink(filename_failed);
 194                 delete_path(filename_failed);
 195
 196                 strlcpy(target, sysfs_path, sizeof(target));
 197                 strlcat(target, msg->devpath, sizeof(target));
 198                 create_path(filename);
 199                 symlink(target, filename);
 200                 return;
 201         case EVENT_FINISHED:
 202         case EVENT_FAILED:
 203                 unlink(filename_failed);
 204                 delete_path(filename_failed);
 205
 206                 /* don't remove, if events for the same path are still pending */
 207                 list_for_each_entry(loop_msg, &running_list, node)
 208                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 209                                 return;
 210
 211                 list_for_each_entry(loop_msg, &exec_list, node)
 212                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 213                                 return;
 214
 215                 /* move failed events to the failed directory */
 216                 if (state == EVENT_FAILED) {
 217                         create_path(filename_failed);
 218                         rename(filename, filename_failed);
 219                 } else {
 220                         unlink(filename);
 221                 }
 222
 223                 /* clean up the queue directory */
 224                 delete_path(filename);
 225
 226                 return;
 227         }
 228 }
 229
 230 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 231 {
 232         list_del(&msg->node);
 233
 234         /* mark as failed, if add event returns non-zero */
 235         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 236                 export_event_state(msg, EVENT_FAILED);
 237         else
 238                 export_event_state(msg, EVENT_FINISHED);
 239
 240         free(msg);
 241 }
 242
 243 static void udev_event_run(struct udevd_uevent_msg *msg)
 244 {
 245         pid_t pid;
 246         int retval;
 247
 248         pid = fork();
 249         switch (pid) {
 250         case 0:
 251                 /* child */
 252                 close(uevent_netlink_sock);
 253                 close(udevd_sock);
 254                 if (inotify_fd >= 0)
 255                         close(inotify_fd);
 256                 close(signal_pipe[READ_END]);
 257                 close(signal_pipe[WRITE_END]);
 258                 logging_close();
 259
 260                 logging_init("udevd-event");
 261                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 262
 263                 retval = udev_event_process(msg);
 264                 info("seq %llu finished", msg->seqnum);
 265
 266                 logging_close();
 267                 if (retval)
 268                         exit(1);
 269                 exit(0);
 270         case -1:
 271                 err("fork of child failed: %s", strerror(errno));
 272                 msg_queue_delete(msg);
 273                 break;
 274         default:
 275                 /* get SIGCHLD in main loop */
 276                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 277                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 278                 msg->pid = pid;
 279         }
 280 }
 281
 282 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 283 {
 284         char filename[PATH_SIZE];
 285         int fd;
 286
 287         msg->queue_time = time(NULL);
 288
 289         strlcpy(filename, udev_root, sizeof(filename));
 290         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 291         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 292         if (fd >= 0) {
 293                 char str[32];
 294                 int len;
 295
 296                 len = sprintf(str, "%llu\n", msg->seqnum);
 297                 write(fd, str, len);
 298                 close(fd);
 299         }
 300
 301         export_event_state(msg, EVENT_QUEUED);
 302
 303         /* run all events with a timeout set immediately */
 304         if (msg->timeout != 0) {
 305                 list_add_tail(&msg->node, &running_list);
 306                 udev_event_run(msg);
 307                 return;
 308         }
 309
 310         list_add_tail(&msg->node, &exec_list);
 311         run_exec_q = 1;
 312 }
 313
 314 static int mem_size_mb(void)
 315 {
 316         int f;
 317         char buf[8192];
 318         long int len;
 319         const char *pos;
 320         long int memsize;
 321
 322         f = open("/proc/meminfo", O_RDONLY);
 323         if (f == -1)
 324                 return -1;
 325
 326         len = read(f, buf, sizeof(buf)-1);
 327         close(f);
 328
 329         if (len <= 0)
 330                 return -1;
 331         buf[len] = '\0';
 332
 333         pos = strstr(buf, "MemTotal: ");
 334         if (pos == NULL)
 335                 return -1;
 336
 337         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 338                 return -1;
 339
 340         return memsize / 1024;
 341 }
 342
 343 static int cpu_count(void)
 344 {
 345         int f;
 346         char buf[32768];
 347         int len;
 348         const char *pos;
 349         int count = 0;
 350
 351         f = open("/proc/stat", O_RDONLY);
 352         if (f == -1)
 353                 return -1;
 354
 355         len = read(f, buf, sizeof(buf)-1);
 356         close(f);
 357         if (len <= 0)
 358                 return -1;
 359         buf[len] = '\0';
 360
 361         pos = strstr(buf, "cpu");
 362         if (pos == NULL)
 363                 return -1;
 364
 365         while (pos != NULL) {
 366                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 367                         count++;
 368                 pos = strstr(&pos[3], "cpu");
 369         }
 370
 371         if (count == 0)
 372                 return -1;
 373         return count;
 374 }
 375
 376 static int running_processes(void)
 377 {
 378         int f;
 379         char buf[32768];
 380         int len;
 381         int running;
 382         const char *pos;
 383
 384         f = open("/proc/stat", O_RDONLY);
 385         if (f == -1)
 386                 return -1;
 387
 388         len = read(f, buf, sizeof(buf)-1);
 389         close(f);
 390         if (len <= 0)
 391                 return -1;
 392         buf[len] = '\0';
 393
 394         pos = strstr(buf, "procs_running ");
 395         if (pos == NULL)
 396                 return -1;
 397
 398         if (sscanf(pos, "procs_running %u", &running) != 1)
 399                 return -1;
 400
 401         return running;
 402 }
 403
 404 /* return the number of process es in our session, count only until limit */
 405 static int running_processes_in_session(pid_t session, int limit)
 406 {
 407         DIR *dir;
 408         struct dirent *dent;
 409         int running = 0;
 410
 411         dir = opendir("/proc");
 412         if (!dir)
 413                 return -1;
 414
 415         /* read process info from /proc */
 416         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 417                 int f;
 418                 char procdir[64];
 419                 char line[256];
 420                 const char *pos;
 421                 char state;
 422                 pid_t ppid, pgrp, sess;
 423                 int len;
 424
 425                 if (!isdigit(dent->d_name[0]))
 426                         continue;
 427
 428                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 429                 procdir[sizeof(procdir)-1] = '\0';
 430
 431                 f = open(procdir, O_RDONLY);
 432                 if (f == -1)
 433                         continue;
 434
 435                 len = read(f, line, sizeof(line)-1);
 436                 close(f);
 437
 438                 if (len <= 0)
 439                         continue;
 440                 else
 441                         line[len] = '\0';
 442
 443                 /* skip ugly program name */
 444                 pos = strrchr(line, ')') + 2;
 445                 if (pos == NULL)
 446                         continue;
 447
 448                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 449                         continue;
 450
 451                 /* count only processes in our session */
 452                 if (sess != session)
 453                         continue;
 454
 455                 /* count only running, no sleeping processes */
 456                 if (state != 'R')
 457                         continue;
 458
 459                 running++;
 460                 if (limit > 0 && running >= limit)
 461                         break;
 462         }
 463         closedir(dir);
 464
 465         return running;
 466 }
 467
 468 static int compare_devpath(const char *running, const char *waiting)
 469 {
 470         int i;
 471
 472         for (i = 0; i < PATH_SIZE; i++) {
 473                 /* identical device event found */
 474                 if (running[i] == '\0' && waiting[i] == '\0')
 475                         return 1;
 476
 477                 /* parent device event found */
 478                 if (running[i] == '\0' && waiting[i] == '/')
 479                         return 2;
 480
 481                 /* child device event found */
 482                 if (running[i] == '/' && waiting[i] == '\0')
 483                         return 3;
 484
 485                 /* no matching event */
 486                 if (running[i] != waiting[i])
 487                         break;
 488         }
 489
 490         return 0;
 491 }
 492
 493 /* returns still running task for the same device, its parent or its physical device */
 494 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 495 {
 496         struct udevd_uevent_msg *loop_msg;
 497         int childs_count = 0;
 498
 499         list_for_each_entry(loop_msg, &running_list, node) {
 500                 if (limit && childs_count++ > limit) {
 501                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 502                         return 1;
 503                 }
 504
 505                 /* return running parent/child device event */
 506                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 507                         dbg("%llu, child device event still running %llu (%s)",
 508                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 509                         return 2;
 510                 }
 511
 512                 /* return running physical device event */
 513                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 514                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 515                                 dbg("%llu, physical device event still running %llu (%s)",
 516                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 517                                 return 3;
 518                         }
 519         }
 520
 521         return 0;
 522 }
 523
 524 /* exec queue management routine executes the events and serializes events in the same sequence */
 525 static void msg_queue_manager(void)
 526 {
 527         struct udevd_uevent_msg *loop_msg;
 528         struct udevd_uevent_msg *tmp_msg;
 529         int running;
 530
 531         if (list_empty(&exec_list))
 532                 return;
 533
 534         running = running_processes();
 535         dbg("%d processes runnning on system", running);
 536         if (running < 0)
 537                 running = max_childs_running;
 538
 539         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 540                 /* check running processes in our session and possibly throttle */
 541                 if (running >= max_childs_running) {
 542                         running = running_processes_in_session(sid, max_childs_running+10);
 543                         dbg("at least %d processes running in session", running);
 544                         if (running >= max_childs_running) {
 545                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 546                                 return;
 547                         }
 548                 }
 549
 550                 /* don't run two processes for the same devpath and wait for the parent*/
 551                 if (running_with_devpath(loop_msg, max_childs)) {
 552                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 553                         continue;
 554                 }
 555
 556                 /* move event to run list */
 557                 list_move_tail(&loop_msg->node, &running_list);
 558                 udev_event_run(loop_msg);
 559                 running++;
 560                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 561         }
 562 }
 563
 564 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 565 {
 566         int bufpos;
 567         int i;
 568         struct udevd_uevent_msg *msg;
 569         int major = 0;
 570         int minor = 0;
 571
 572         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 573         if (msg == NULL)
 574                 return NULL;
 575         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 576
 577         /* copy environment buffer and reconstruct envp */
 578         memcpy(msg->envbuf, buf, buf_size);
 579         bufpos = 0;
 580         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 581                 int keylen;
 582                 char *key;
 583
 584                 key = &msg->envbuf[bufpos];
 585                 keylen = strlen(key);
 586                 msg->envp[i] = key;
 587                 bufpos += keylen + 1;
 588                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 589
 590                 /* remember some keys for further processing */
 591                 if (strncmp(key, "ACTION=", 7) == 0)
 592                         msg->action = &key[7];
 593                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 594                         msg->devpath = &key[8];
 595                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 596                         msg->subsystem = &key[10];
 597                 else if (strncmp(key, "DRIVER=", 7) == 0)
 598                         msg->driver = &key[7];
 599                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 600                         msg->seqnum = strtoull(&key[7], NULL, 10);
 601                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 602                         msg->physdevpath = &key[12];
 603                 else if (strncmp(key, "MAJOR=", 6) == 0)
 604                         major = strtoull(&key[6], NULL, 10);
 605                 else if (strncmp(key, "MINOR=", 6) == 0)
 606                         minor = strtoull(&key[6], NULL, 10);
 607                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 608                         msg->timeout = strtoull(&key[8], NULL, 10);
 609         }
 610         msg->devt = makedev(major, minor);
 611         msg->envp[i++] = "UDEVD_EVENT=1";
 612         msg->envp[i] = NULL;
 613
 614         if (msg->devpath == NULL || msg->action == NULL) {
 615                 info("DEVPATH or ACTION missing, ignore message");
 616                 free(msg);
 617                 return NULL;
 618         }
 619         return msg;
 620 }
 621
 622 /* receive the udevd message from userspace */
 623 static void get_ctrl_msg(void)
 624 {
 625         struct udevd_ctrl_msg ctrl_msg;
 626         ssize_t size;
 627         struct msghdr smsg;
 628         struct cmsghdr *cmsg;
 629         struct iovec iov;
 630         struct ucred *cred;
 631         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 632         int *intval;
 633
 634         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 635         iov.iov_base = &ctrl_msg;
 636         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 637
 638         memset(&smsg, 0x00, sizeof(struct msghdr));
 639         smsg.msg_iov = &iov;
 640         smsg.msg_iovlen = 1;
 641         smsg.msg_control = cred_msg;
 642         smsg.msg_controllen = sizeof(cred_msg);
 643
 644         size = recvmsg(udevd_sock, &smsg, 0);
 645         if (size <  0) {
 646                 if (errno != EINTR)
 647                         err("unable to receive user udevd message: %s", strerror(errno));
 648                 return;
 649         }
 650         cmsg = CMSG_FIRSTHDR(&smsg);
 651         cred = (struct ucred *) CMSG_DATA(cmsg);
 652
 653         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 654                 err("no sender credentials received, message ignored");
 655                 return;
 656         }
 657
 658         if (cred->uid != 0) {
 659                 err("sender uid=%i, message ignored", cred->uid);
 660                 return;
 661         }
 662
 663         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 664                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 665                 return;
 666         }
 667
 668         switch (ctrl_msg.type) {
 669         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 670                 info("udevd message (STOP_EXEC_QUEUE) received");
 671                 stop_exec_q = 1;
 672                 break;
 673         case UDEVD_CTRL_START_EXEC_QUEUE:
 674                 info("udevd message (START_EXEC_QUEUE) received");
 675                 stop_exec_q = 0;
 676                 msg_queue_manager();
 677                 break;
 678         case UDEVD_CTRL_SET_LOG_LEVEL:
 679                 intval = (int *) ctrl_msg.buf;
 680                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 681                 udev_log_priority = *intval;
 682                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 683                 putenv(udev_log);
 684                 break;
 685         case UDEVD_CTRL_SET_MAX_CHILDS:
 686                 intval = (int *) ctrl_msg.buf;
 687                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 688                 max_childs = *intval;
 689                 break;
 690         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 691                 intval = (int *) ctrl_msg.buf;
 692                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 693                 max_childs_running = *intval;
 694                 break;
 695         case UDEVD_CTRL_RELOAD_RULES:
 696                 info("udevd message (RELOAD_RULES) received");
 697                 reload_config = 1;
 698                 break;
 699         default:
 700                 err("unknown control message type");
 701         }
 702 }
 703
 704 /* receive the kernel user event message and do some sanity checks */
 705 static struct udevd_uevent_msg *get_netlink_msg(void)
 706 {
 707         struct udevd_uevent_msg *msg;
 708         int bufpos;
 709         ssize_t size;
 710         static char buffer[UEVENT_BUFFER_SIZE+512];
 711         char *pos;
 712
 713         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 714         if (size <  0) {
 715                 if (errno != EINTR)
 716                         err("unable to receive kernel netlink message: %s", strerror(errno));
 717                 return NULL;
 718         }
 719
 720         if ((size_t)size > sizeof(buffer)-1)
 721                 size = sizeof(buffer)-1;
 722         buffer[size] = '\0';
 723         dbg("uevent_size=%zi", size);
 724
 725         /* start of event payload */
 726         bufpos = strlen(buffer)+1;
 727         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 728         if (msg == NULL)
 729                 return NULL;
 730
 731         /* validate message */
 732         pos = strchr(buffer, '@');
 733         if (pos == NULL) {
 734                 err("invalid uevent '%s'", buffer);
 735                 free(msg);
 736                 return NULL;
 737         }
 738         pos[0] = '\0';
 739
 740         if (msg->action == NULL) {
 741                 info("no ACTION in payload found, skip event '%s'", buffer);
 742                 free(msg);
 743                 return NULL;
 744         }
 745
 746         if (strcmp(msg->action, buffer) != 0) {
 747                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 748                 free(msg);
 749                 return NULL;
 750         }
 751
 752         return msg;
 753 }
 754
 755 static void asmlinkage sig_handler(int signum)
 756 {
 757         switch (signum) {
 758                 case SIGINT:
 759                 case SIGTERM:
 760                         udev_exit = 1;
 761                         break;
 762                 case SIGCHLD:
 763                         /* set flag, then write to pipe if needed */
 764                         sigchilds_waiting = 1;
 765                         break;
 766                 case SIGHUP:
 767                         reload_config = 1;
 768                         break;
 769         }
 770
 771         /* write to pipe, which will wakeup select() in our mainloop */
 772         write(signal_pipe[WRITE_END], "", 1);
 773 }
 774
 775 static void udev_done(int pid, int exitstatus)
 776 {
 777         /* find msg associated with pid and delete it */
 778         struct udevd_uevent_msg *msg;
 779
 780         list_for_each_entry(msg, &running_list, node) {
 781                 if (msg->pid == pid) {
 782                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 783                              exitstatus, time(NULL) - msg->queue_time);
 784                         msg->exitstatus = exitstatus;
 785                         msg_queue_delete(msg);
 786
 787                         /* there may be events waiting with the same devpath */
 788                         run_exec_q = 1;
 789                         return;
 790                 }
 791         }
 792 }
 793
 794 static void reap_sigchilds(void)
 795 {
 796         pid_t pid;
 797         int status;
 798
 799         while (1) {
 800                 pid = waitpid(-1, &status, WNOHANG);
 801                 if (pid <= 0)
 802                         break;
 803                 if (WIFEXITED(status))
 804                         status = WEXITSTATUS(status);
 805                 else if (WIFSIGNALED(status))
 806                         status = WTERMSIG(status) + 128;
 807                 else
 808                         status = 0;
 809                 udev_done(pid, status);
 810         }
 811 }
 812
 813 static int init_udevd_socket(void)
 814 {
 815         struct sockaddr_un saddr;
 816         socklen_t addrlen;
 817         const int feature_on = 1;
 818         int retval;
 819
 820         memset(&saddr, 0x00, sizeof(saddr));
 821         saddr.sun_family = AF_LOCAL;
 822         /* use abstract namespace for socket path */
 823         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 824         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 825
 826         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 827         if (udevd_sock == -1) {
 828                 err("error getting socket: %s", strerror(errno));
 829                 return -1;
 830         }
 831
 832         /* the bind takes care of ensuring only one copy running */
 833         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 834         if (retval < 0) {
 835                 err("bind failed: %s", strerror(errno));
 836                 close(udevd_sock);
 837                 udevd_sock = -1;
 838                 return -1;
 839         }
 840
 841         /* enable receiving of the sender credentials */
 842         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 843
 844         return 0;
 845 }
 846
 847 static int init_uevent_netlink_sock(void)
 848 {
 849         struct sockaddr_nl snl;
 850         const int buffersize = 16 * 1024 * 1024;
 851         int retval;
 852
 853         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 854         snl.nl_family = AF_NETLINK;
 855         snl.nl_pid = getpid();
 856         snl.nl_groups = 1;
 857
 858         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 859         if (uevent_netlink_sock == -1) {
 860                 err("error getting socket: %s", strerror(errno));
 861                 return -1;
 862         }
 863
 864         /* set receive buffersize */
 865         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 866
 867         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 868         if (retval < 0) {
 869                 err("bind failed: %s", strerror(errno));
 870                 close(uevent_netlink_sock);
 871                 uevent_netlink_sock = -1;
 872                 return -1;
 873         }
 874         return 0;
 875 }
 876
 877 static void export_initial_seqnum(void)
 878 {
 879         char filename[PATH_SIZE];
 880         int fd;
 881         char seqnum[32];
 882         ssize_t len = 0;
 883
 884         strlcpy(filename, sysfs_path, sizeof(filename));
 885         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 886         fd = open(filename, O_RDONLY);
 887         if (fd >= 0) {
 888                 len = read(fd, seqnum, sizeof(seqnum)-1);
 889                 close(fd);
 890         }
 891         if (len <= 0) {
 892                 strcpy(seqnum, "0\n");
 893                 len = 3;
 894         }
 895         strlcpy(filename, udev_root, sizeof(filename));
 896         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 897         create_path(filename);
 898         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 899         if (fd >= 0) {
 900                 write(fd, seqnum, len);
 901                 close(fd);
 902         }
 903 }
 904
 905 int main(int argc, char *argv[], char *envp[])
 906 {
 907         int retval;
 908         int fd;
 909         struct sigaction act;
 910         fd_set readfds;
 911         const char *value;
 912         int daemonize = 0;
 913         int i;
 914         int rc = 0;
 915         int maxfd;
 916
 917         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 918         fd = open("/dev/null", O_RDWR);
 919         if (fd >= 0) {
 920                 if (fd != STDIN_FILENO)
 921                         dup2(fd, STDIN_FILENO);
 922                 if (fd != STDOUT_FILENO)
 923                         dup2(fd, STDOUT_FILENO);
 924                 if (fd != STDERR_FILENO)
 925                         dup2(fd, STDERR_FILENO);
 926                 if (fd > STDERR_FILENO)
 927                         close(fd);
 928         }
 929
 930         logging_init("udevd");
 931         if (fd < 0)
 932                 err("fatal, could not open /dev/null: %s", strerror(errno));
 933
 934         udev_config_init();
 935         selinux_init();
 936         dbg("version %s", UDEV_VERSION);
 937
 938         if (getuid() != 0) {
 939                 err("need to be root, exit");
 940                 goto exit;
 941         }
 942
 943         /* parse commandline options */
 944         for (i = 1 ; i < argc; i++) {
 945                 char *arg = argv[i];
 946                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 947                         info("will daemonize");
 948                         daemonize = 1;
 949                 }
 950         }
 951
 952         /* init sockets to receive events */
 953         if (init_udevd_socket() < 0) {
 954                 if (errno == EADDRINUSE) {
 955                         err("another udevd running, exit");
 956                         rc = 1;
 957                 } else {
 958                         err("error initializing udevd socket: %s", strerror(errno));
 959                         rc = 2;
 960                 }
 961                 goto exit;
 962         }
 963
 964         if (init_uevent_netlink_sock() < 0) {
 965                 err("uevent socket not available");
 966                 rc = 3;
 967                 goto exit;
 968         }
 969
 970         /* parse the rules and keep it in memory */
 971         sysfs_init();
 972         udev_rules_init(&rules, 1);
 973
 974         export_initial_seqnum();
 975
 976         if (daemonize) {
 977                 pid_t pid;
 978
 979                 pid = fork();
 980                 switch (pid) {
 981                 case 0:
 982                         dbg("daemonized fork running");
 983                         break;
 984                 case -1:
 985                         err("fork of daemon failed: %s", strerror(errno));
 986                         rc = 4;
 987                         goto exit;
 988                 default:
 989                         dbg("child [%u] running, parent exits", pid);
 990                         goto exit;
 991                 }
 992         }
 993
 994         /* set scheduling priority for the daemon */
 995         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 996
 997         chdir("/");
 998         umask(022);
 999
1000         /* become session leader */
1001         sid = setsid();
1002         dbg("our session is %d", sid);
1003
1004         /* OOM_DISABLE == -17 */
1005         fd = open("/proc/self/oom_adj", O_RDWR);
1006         if (fd < 0)
1007                 err("error disabling OOM: %s", strerror(errno));
1008         else {
1009                 write(fd, "-17", 3);
1010                 close(fd);
1011         }
1012
1013         /* setup signal handler pipe */
1014         retval = pipe(signal_pipe);
1015         if (retval < 0) {
1016                 err("error getting pipes: %s", strerror(errno));
1017                 goto exit;
1018         }
1019
1020         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1021         if (retval < 0) {
1022                 err("error fcntl on read pipe: %s", strerror(errno));
1023                 goto exit;
1024         }
1025         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1026         if (retval < 0) {
1027                 err("error fcntl on read pipe: %s", strerror(errno));
1028                 goto exit;
1029         }
1030
1031         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1032         if (retval < 0) {
1033                 err("error fcntl on write pipe: %s", strerror(errno));
1034                 goto exit;
1035         }
1036         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1037         if (retval < 0) {
1038                 err("error fcntl on write pipe: %s", strerror(errno));
1039                 goto exit;
1040         }
1041
1042         /* set signal handlers */
1043         memset(&act, 0x00, sizeof(struct sigaction));
1044         act.sa_handler = (void (*)(int)) sig_handler;
1045         sigemptyset(&act.sa_mask);
1046         act.sa_flags = SA_RESTART;
1047         sigaction(SIGINT, &act, NULL);
1048         sigaction(SIGTERM, &act, NULL);
1049         sigaction(SIGCHLD, &act, NULL);
1050         sigaction(SIGHUP, &act, NULL);
1051
1052         /* watch rules directory */
1053         inotify_fd = inotify_init();
1054         if (inotify_fd >= 0)
1055                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1056         else if (errno == ENOSYS)
1057                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1058         else
1059                 err("inotify_init failed: %s", strerror(errno));
1060
1061         /* maximum limit of forked childs */
1062         value = getenv("UDEVD_MAX_CHILDS");
1063         if (value)
1064                 max_childs = strtoul(value, NULL, 10);
1065         else {
1066                 int memsize = mem_size_mb();
1067                 if (memsize > 0)
1068                         max_childs = 128 + (memsize / 4);
1069                 else
1070                         max_childs = UDEVD_MAX_CHILDS;
1071         }
1072         info("initialize max_childs to %u", max_childs);
1073
1074         /* start to throttle forking if maximum number of _running_ childs is reached */
1075         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1076         if (value)
1077                 max_childs_running = strtoull(value, NULL, 10);
1078         else {
1079                 int cpus = cpu_count();
1080                 if (cpus > 0)
1081                         max_childs_running = 8 + (8 * cpus);
1082                 else
1083                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1084         }
1085         info("initialize max_childs_running to %u", max_childs_running);
1086
1087         /* clear environment for forked event processes */
1088         clearenv();
1089
1090         /* export log_priority , as called programs may want to follow that setting */
1091         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1092         putenv(udev_log);
1093
1094         maxfd = udevd_sock;
1095         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1096         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1097         maxfd = UDEV_MAX(maxfd, inotify_fd);
1098
1099         while (!udev_exit) {
1100                 struct udevd_uevent_msg *msg;
1101                 int fdcount;
1102
1103                 FD_ZERO(&readfds);
1104                 FD_SET(signal_pipe[READ_END], &readfds);
1105                 FD_SET(udevd_sock, &readfds);
1106                 FD_SET(uevent_netlink_sock, &readfds);
1107                 if (inotify_fd >= 0)
1108                         FD_SET(inotify_fd, &readfds);
1109
1110                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1111                 if (fdcount < 0) {
1112                         if (errno != EINTR)
1113                                 err("error in select: %s", strerror(errno));
1114                         continue;
1115                 }
1116
1117                 /* get control message */
1118                 if (FD_ISSET(udevd_sock, &readfds))
1119                         get_ctrl_msg();
1120
1121                 /* get netlink message */
1122                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1123                         msg = get_netlink_msg();
1124                         if (msg)
1125                                 msg_queue_insert(msg);
1126                 }
1127
1128                 /* received a signal, clear our notification pipe */
1129                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1130                         char buf[256];
1131
1132                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1133                 }
1134
1135                 /* rules directory inotify watch */
1136                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1137                         int nbytes;
1138
1139                         /* discard all possible events, we can just reload the config */
1140                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1141                                 char *buf;
1142
1143                                 reload_config = 1;
1144                                 buf = malloc(nbytes);
1145                                 if (!buf) {
1146                                         err("error getting buffer for inotify, disable watching");
1147                                         close(inotify_fd);
1148                                         inotify_fd = -1;
1149                                 }
1150                                 read(inotify_fd, buf, nbytes);
1151                                 free(buf);
1152                         }
1153                 }
1154
1155                 /* rules changed, set by inotify or a signal*/
1156                 if (reload_config) {
1157                         reload_config = 0;
1158                         udev_rules_cleanup(&rules);
1159                         udev_rules_init(&rules, 1);
1160                 }
1161
1162                 /* forked child has returned */
1163                 if (sigchilds_waiting) {
1164                         sigchilds_waiting = 0;
1165                         reap_sigchilds();
1166                 }
1167
1168                 if (run_exec_q) {
1169                         run_exec_q = 0;
1170                         if (!stop_exec_q)
1171                                 msg_queue_manager();
1172                 }
1173         }
1174
1175 exit:
1176         udev_rules_cleanup(&rules);
1177         sysfs_cleanup();
1178
1179         if (signal_pipe[READ_END] >= 0)
1180                 close(signal_pipe[READ_END]);
1181         if (signal_pipe[WRITE_END] >= 0)
1182                 close(signal_pipe[WRITE_END]);
1183
1184         if (udevd_sock >= 0)
1185                 close(udevd_sock);
1186         if (inotify_fd >= 0)
1187                 close(inotify_fd);
1188         if (uevent_netlink_sock >= 0)
1189                 close(uevent_netlink_sock);
1190
1191         logging_close();
1192
1193         return rc;
1194 }