udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2005 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
  49 static struct udev_rules rules;
  50 static int udevd_sock;
  51 static int uevent_netlink_sock;
  52 static int inotify_fd;
  53 static pid_t sid;
  54
  55 static int signal_pipe[2] = {-1, -1};
  56 static volatile int sigchilds_waiting;
  57 static volatile int udev_exit;
  58 static volatile int reload_config;
  59 static int run_exec_q;
  60 static int stop_exec_q;
  61 static int max_childs;
  62 static int max_childs_running;
  63 static char udev_log[32];
  64
  65 static LIST_HEAD(exec_list);
  66 static LIST_HEAD(running_list);
  67
  68
  69 #ifdef USE_LOG
  70 void log_message(int priority, const char *format, ...)
  71 {
  72         va_list args;
  73
  74         if (priority > udev_log_priority)
  75                 return;
  76
  77         va_start(args, format);
  78         vsyslog(priority, format, args);
  79         va_end(args);
  80 }
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* reset to default */
 104         act.sa_handler = SIG_DFL;
 105         sigaction(SIGINT, &act, NULL);
 106         sigaction(SIGTERM, &act, NULL);
 107         sigaction(SIGCHLD, &act, NULL);
 108         sigaction(SIGHUP, &act, NULL);
 109
 110         /* trigger timeout to prevent hanging processes */
 111         alarm(UDEV_ALARM_TIMEOUT);
 112
 113         /* reconstruct event environment from message */
 114         for (i = 0; msg->envp[i]; i++)
 115                 putenv(msg->envp[i]);
 116
 117         udev = udev_device_init();
 118         if (udev == NULL)
 119                 return -1;
 120         strlcpy(udev->action, msg->action, sizeof(udev->action));
 121         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
 122         udev->devt = msg->devt;
 123
 124         retval = udev_device_event(&rules, udev);
 125
 126         /* run programs collected by RUN-key*/
 127         if (retval == 0 && !udev->ignore_device && udev_run) {
 128                 struct name_entry *name_loop;
 129
 130                 dbg("executing run list");
 131                 list_for_each_entry(name_loop, &udev->run_list, node) {
 132                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 133                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
 134                         else {
 135                                 char program[PATH_SIZE];
 136
 137                                 strlcpy(program, name_loop->name, sizeof(program));
 138                                 udev_rules_apply_format(udev, program, sizeof(program));
 139                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 140                                                 (udev_log_priority >= LOG_INFO)))
 141                                         retval = -1;
 142                         }
 143                 }
 144         }
 145
 146         udev_device_cleanup(udev);
 147         return retval;
 148 }
 149
 150 enum event_state {
 151         EVENT_QUEUED,
 152         EVENT_FINISHED,
 153         EVENT_FAILED,
 154 };
 155
 156 static void export_event_state(struct uevent_msg *msg, enum event_state state)
 157 {
 158         char filename[PATH_SIZE];
 159         char filename_failed[PATH_SIZE];
 160         char target[PATH_SIZE];
 161         size_t start, end, i;
 162         struct uevent_msg *loop_msg;
 163
 164         /* add location of queue files */
 165         strlcpy(filename, udev_root, sizeof(filename));
 166         strlcat(filename, "/", sizeof(filename));
 167         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 168         end = strlcat(filename, msg->devpath, sizeof(filename));
 169         if (end > sizeof(filename))
 170                 end = sizeof(filename);
 171
 172         /* replace '/' to transform path into a filename */
 173         for (i = start+1; i < end; i++)
 174                 if (filename[i] == '/')
 175                         filename[i] = PATH_TO_NAME_CHAR;
 176
 177         /* add location of failed files */
 178         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 179         strlcat(filename_failed, "/", sizeof(filename_failed));
 180         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 181         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 182         if (end > sizeof(filename_failed))
 183                 end = sizeof(filename_failed);
 184
 185         /* replace '/' to transform path into a filename */
 186         for (i = start+1; i < end; i++)
 187                 if (filename_failed[i] == '/')
 188                         filename_failed[i] = PATH_TO_NAME_CHAR;
 189
 190         switch (state) {
 191         case EVENT_QUEUED:
 192                 unlink(filename_failed);
 193                 delete_path(filename_failed);
 194
 195                 strlcpy(target, sysfs_path, sizeof(target));
 196                 strlcat(target, msg->devpath, sizeof(target));
 197                 create_path(filename);
 198                 symlink(target, filename);
 199                 return;
 200         case EVENT_FINISHED:
 201         case EVENT_FAILED:
 202                 unlink(filename_failed);
 203                 delete_path(filename_failed);
 204
 205                 /* don't remove, if events for the same path are still pending */
 206                 list_for_each_entry(loop_msg, &running_list, node)
 207                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 208                                 return;
 209
 210                 list_for_each_entry(loop_msg, &exec_list, node)
 211                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 212                                 return;
 213
 214                 /* move failed events to the failed directory */
 215                 if (state == EVENT_FAILED) {
 216                         create_path(filename_failed);
 217                         rename(filename, filename_failed);
 218                 } else {
 219                         unlink(filename);
 220                 }
 221
 222                 /* clean up the queue directory */
 223                 delete_path(filename);
 224
 225                 return;
 226         }
 227 }
 228
 229 static void msg_queue_delete(struct uevent_msg *msg)
 230 {
 231         list_del(&msg->node);
 232
 233         /* mark as failed, if add event returns non-zero */
 234         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 235                 export_event_state(msg, EVENT_FAILED);
 236         else
 237                 export_event_state(msg, EVENT_FINISHED);
 238
 239         free(msg);
 240 }
 241
 242 static void udev_event_run(struct uevent_msg *msg)
 243 {
 244         pid_t pid;
 245         int retval;
 246
 247         pid = fork();
 248         switch (pid) {
 249         case 0:
 250                 /* child */
 251                 close(uevent_netlink_sock);
 252                 close(udevd_sock);
 253                 if (inotify_fd > 0)
 254                         close(inotify_fd);
 255                 close(signal_pipe[READ_END]);
 256                 close(signal_pipe[WRITE_END]);
 257                 logging_close();
 258
 259                 logging_init("udevd-event");
 260                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 261                 retval = udev_event_process(msg);
 262                 info("seq %llu finished", msg->seqnum);
 263
 264                 logging_close();
 265                 if (retval)
 266                         exit(1);
 267                 exit(0);
 268         case -1:
 269                 err("fork of child failed: %s", strerror(errno));
 270                 msg_queue_delete(msg);
 271                 break;
 272         default:
 273                 /* get SIGCHLD in main loop */
 274                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 275                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 276                 msg->pid = pid;
 277         }
 278 }
 279
 280 static void msg_queue_insert(struct uevent_msg *msg)
 281 {
 282         msg->queue_time = time(NULL);
 283
 284         export_event_state(msg, EVENT_QUEUED);
 285
 286         /* run all events with a timeout set immediately */
 287         if (msg->timeout != 0) {
 288                 list_add_tail(&msg->node, &running_list);
 289                 udev_event_run(msg);
 290                 return;
 291         }
 292
 293         list_add_tail(&msg->node, &exec_list);
 294         run_exec_q = 1;
 295 }
 296
 297 /* runs event and removes event from run queue when finished */
 298 static int running_processes(void)
 299 {
 300         int f;
 301         static char buf[4096];
 302         int len;
 303         int running;
 304         const char *pos;
 305
 306         f = open("/proc/stat", O_RDONLY);
 307         if (f == -1)
 308                 return -1;
 309
 310         len = read(f, buf, sizeof(buf)-1);
 311         close(f);
 312
 313         if (len <= 0)
 314                 return -1;
 315         else
 316                 buf[len] = '\0';
 317
 318         pos = strstr(buf, "procs_running ");
 319         if (pos == NULL)
 320                 return -1;
 321
 322         if (sscanf(pos, "procs_running %u", &running) != 1)
 323                 return -1;
 324
 325         return running;
 326 }
 327
 328 /* return the number of process es in our session, count only until limit */
 329 static int running_processes_in_session(pid_t session, int limit)
 330 {
 331         DIR *dir;
 332         struct dirent *dent;
 333         int running = 0;
 334
 335         dir = opendir("/proc");
 336         if (!dir)
 337                 return -1;
 338
 339         /* read process info from /proc */
 340         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 341                 int f;
 342                 char procdir[64];
 343                 char line[256];
 344                 const char *pos;
 345                 char state;
 346                 pid_t ppid, pgrp, sess;
 347                 int len;
 348
 349                 if (!isdigit(dent->d_name[0]))
 350                         continue;
 351
 352                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 353                 procdir[sizeof(procdir)-1] = '\0';
 354
 355                 f = open(procdir, O_RDONLY);
 356                 if (f == -1)
 357                         continue;
 358
 359                 len = read(f, line, sizeof(line)-1);
 360                 close(f);
 361
 362                 if (len <= 0)
 363                         continue;
 364                 else
 365                         line[len] = '\0';
 366
 367                 /* skip ugly program name */
 368                 pos = strrchr(line, ')') + 2;
 369                 if (pos == NULL)
 370                         continue;
 371
 372                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 373                         continue;
 374
 375                 /* count only processes in our session */
 376                 if (sess != session)
 377                         continue;
 378
 379                 /* count only running, no sleeping processes */
 380                 if (state != 'R')
 381                         continue;
 382
 383                 running++;
 384                 if (limit > 0 && running >= limit)
 385                         break;
 386         }
 387         closedir(dir);
 388
 389         return running;
 390 }
 391
 392 static int compare_devpath(const char *running, const char *waiting)
 393 {
 394         int i;
 395
 396         for (i = 0; i < PATH_SIZE; i++) {
 397                 /* identical device event found */
 398                 if (running[i] == '\0' && waiting[i] == '\0')
 399                         return 1;
 400
 401                 /* parent device event found */
 402                 if (running[i] == '\0' && waiting[i] == '/')
 403                         return 2;
 404
 405                 /* child device event found */
 406                 if (running[i] == '/' && waiting[i] == '\0')
 407                         return 3;
 408
 409                 /* no matching event */
 410                 if (running[i] != waiting[i])
 411                         break;
 412         }
 413
 414         return 0;
 415 }
 416
 417 /* returns still running task for the same device, its parent or its physical device */
 418 static int running_with_devpath(struct uevent_msg *msg, int limit)
 419 {
 420         struct uevent_msg *loop_msg;
 421         int childs_count = 0;
 422
 423         list_for_each_entry(loop_msg, &running_list, node) {
 424                 if (limit && childs_count++ > limit) {
 425                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 426                         return 1;
 427                 }
 428
 429                 /* return running parent/child device event */
 430                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 431                         dbg("%llu, child device event still running %llu (%s)",
 432                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 433                         return 2;
 434                 }
 435
 436                 /* return running physical device event */
 437                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 438                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 439                                 dbg("%llu, physical device event still running %llu (%s)",
 440                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 441                                 return 3;
 442                         }
 443         }
 444
 445         return 0;
 446 }
 447
 448 /* exec queue management routine executes the events and serializes events in the same sequence */
 449 static void msg_queue_manager(void)
 450 {
 451         struct uevent_msg *loop_msg;
 452         struct uevent_msg *tmp_msg;
 453         int running;
 454
 455         if (list_empty(&exec_list))
 456                 return;
 457
 458         running = running_processes();
 459         dbg("%d processes runnning on system", running);
 460         if (running < 0)
 461                 running = max_childs_running;
 462
 463         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 464                 /* check running processes in our session and possibly throttle */
 465                 if (running >= max_childs_running) {
 466                         running = running_processes_in_session(sid, max_childs_running+10);
 467                         dbg("at least %d processes running in session", running);
 468                         if (running >= max_childs_running) {
 469                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 470                                 return;
 471                         }
 472                 }
 473
 474                 /* don't run two processes for the same devpath and wait for the parent*/
 475                 if (running_with_devpath(loop_msg, max_childs)) {
 476                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 477                         continue;
 478                 }
 479
 480                 /* move event to run list */
 481                 list_move_tail(&loop_msg->node, &running_list);
 482                 udev_event_run(loop_msg);
 483                 running++;
 484                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 485         }
 486 }
 487
 488 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 489 {
 490         int bufpos;
 491         int i;
 492         struct uevent_msg *msg;
 493         int major = 0;
 494         int minor = 0;
 495
 496         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 497         if (msg == NULL)
 498                 return NULL;
 499         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 500
 501         /* copy environment buffer and reconstruct envp */
 502         memcpy(msg->envbuf, buf, buf_size);
 503         bufpos = 0;
 504         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 505                 int keylen;
 506                 char *key;
 507
 508                 key = &msg->envbuf[bufpos];
 509                 keylen = strlen(key);
 510                 msg->envp[i] = key;
 511                 bufpos += keylen + 1;
 512                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 513
 514                 /* remember some keys for further processing */
 515                 if (strncmp(key, "ACTION=", 7) == 0)
 516                         msg->action = &key[7];
 517                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 518                         msg->devpath = &key[8];
 519                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 520                         msg->subsystem = &key[10];
 521                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 522                         msg->seqnum = strtoull(&key[7], NULL, 10);
 523                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 524                         msg->physdevpath = &key[12];
 525                 else if (strncmp(key, "MAJOR=", 6) == 0)
 526                         major = strtoull(&key[6], NULL, 10);
 527                 else if (strncmp(key, "MINOR=", 6) == 0)
 528                         minor = strtoull(&key[6], NULL, 10);
 529                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 530                         msg->timeout = strtoull(&key[8], NULL, 10);
 531         }
 532         msg->devt = makedev(major, minor);
 533         msg->envp[i++] = "UDEVD_EVENT=1";
 534         msg->envp[i] = NULL;
 535
 536         if (msg->devpath == NULL || msg->action == NULL) {
 537                 info("DEVPATH or ACTION missing, ignore message");
 538                 free(msg);
 539                 return NULL;
 540         }
 541         return msg;
 542 }
 543
 544 /* receive the udevd message from userspace */
 545 static struct uevent_msg *get_udevd_msg(void)
 546 {
 547         static struct udevd_msg usend_msg;
 548         struct uevent_msg *msg;
 549         ssize_t size;
 550         struct msghdr smsg;
 551         struct cmsghdr *cmsg;
 552         struct iovec iov;
 553         struct ucred *cred;
 554         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 555         int envbuf_size;
 556         int *intval;
 557
 558         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 559         iov.iov_base = &usend_msg;
 560         iov.iov_len = sizeof(struct udevd_msg);
 561
 562         memset(&smsg, 0x00, sizeof(struct msghdr));
 563         smsg.msg_iov = &iov;
 564         smsg.msg_iovlen = 1;
 565         smsg.msg_control = cred_msg;
 566         smsg.msg_controllen = sizeof(cred_msg);
 567
 568         size = recvmsg(udevd_sock, &smsg, 0);
 569         if (size <  0) {
 570                 if (errno != EINTR)
 571                         err("unable to receive user udevd message: %s", strerror(errno));
 572                 return NULL;
 573         }
 574         cmsg = CMSG_FIRSTHDR(&smsg);
 575         cred = (struct ucred *) CMSG_DATA(cmsg);
 576
 577         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 578                 err("no sender credentials received, message ignored");
 579                 return NULL;
 580         }
 581
 582         if (cred->uid != 0) {
 583                 err("sender uid=%i, message ignored", cred->uid);
 584                 return NULL;
 585         }
 586
 587         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 588                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 589                 return NULL;
 590         }
 591
 592         switch (usend_msg.type) {
 593         case UDEVD_UEVENT_UDEVSEND:
 594                 info("udevd event message received");
 595                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 596                 dbg("envbuf_size=%i", envbuf_size);
 597                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 598                 if (msg == NULL)
 599                         return NULL;
 600                 msg->type = usend_msg.type;
 601                 return msg;
 602         case UDEVD_STOP_EXEC_QUEUE:
 603                 info("udevd message (STOP_EXEC_QUEUE) received");
 604                 stop_exec_q = 1;
 605                 break;
 606         case UDEVD_START_EXEC_QUEUE:
 607                 info("udevd message (START_EXEC_QUEUE) received");
 608                 stop_exec_q = 0;
 609                 msg_queue_manager();
 610                 break;
 611         case UDEVD_SET_LOG_LEVEL:
 612                 intval = (int *) usend_msg.envbuf;
 613                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 614                 udev_log_priority = *intval;
 615                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 616                 putenv(udev_log);
 617                 break;
 618         case UDEVD_SET_MAX_CHILDS:
 619                 intval = (int *) usend_msg.envbuf;
 620                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 621                 max_childs = *intval;
 622                 break;
 623         case UDEVD_RELOAD_RULES:
 624                 info("udevd message (RELOAD_RULES) received");
 625                 reload_config = 1;
 626                 break;
 627         default:
 628                 dbg("unknown message type");
 629         }
 630         return NULL;
 631 }
 632
 633 /* receive the kernel user event message and do some sanity checks */
 634 static struct uevent_msg *get_netlink_msg(void)
 635 {
 636         struct uevent_msg *msg;
 637         int bufpos;
 638         ssize_t size;
 639         static char buffer[UEVENT_BUFFER_SIZE+512];
 640         char *pos;
 641
 642         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 643         if (size <  0) {
 644                 if (errno != EINTR)
 645                         err("unable to receive kernel netlink message: %s", strerror(errno));
 646                 return NULL;
 647         }
 648
 649         if ((size_t)size > sizeof(buffer)-1)
 650                 size = sizeof(buffer)-1;
 651         buffer[size] = '\0';
 652         dbg("uevent_size=%zi", size);
 653
 654         /* start of event payload */
 655         bufpos = strlen(buffer)+1;
 656         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 657         if (msg == NULL)
 658                 return NULL;
 659         msg->type = UDEVD_UEVENT_NETLINK;
 660
 661         /* validate message */
 662         pos = strchr(buffer, '@');
 663         if (pos == NULL) {
 664                 err("invalid uevent '%s'", buffer);
 665                 free(msg);
 666                 return NULL;
 667         }
 668         pos[0] = '\0';
 669
 670         if (msg->action == NULL) {
 671                 info("no ACTION in payload found, skip event '%s'", buffer);
 672                 free(msg);
 673                 return NULL;
 674         }
 675
 676         if (strcmp(msg->action, buffer) != 0) {
 677                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 678                 free(msg);
 679                 return NULL;
 680         }
 681
 682         return msg;
 683 }
 684
 685 static void asmlinkage sig_handler(int signum)
 686 {
 687         switch (signum) {
 688                 case SIGINT:
 689                 case SIGTERM:
 690                         udev_exit = 1;
 691                         break;
 692                 case SIGCHLD:
 693                         /* set flag, then write to pipe if needed */
 694                         sigchilds_waiting = 1;
 695                         break;
 696                 case SIGHUP:
 697                         reload_config = 1;
 698                         break;
 699         }
 700
 701         /* write to pipe, which will wakeup select() in our mainloop */
 702         write(signal_pipe[WRITE_END], "", 1);
 703 }
 704
 705 static void udev_done(int pid, int exitstatus)
 706 {
 707         /* find msg associated with pid and delete it */
 708         struct uevent_msg *msg;
 709
 710         list_for_each_entry(msg, &running_list, node) {
 711                 if (msg->pid == pid) {
 712                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 713                              exitstatus, time(NULL) - msg->queue_time);
 714                         msg->exitstatus = exitstatus;
 715                         msg_queue_delete(msg);
 716
 717                         /* there may be events waiting with the same devpath */
 718                         run_exec_q = 1;
 719                         return;
 720                 }
 721         }
 722 }
 723
 724 static void reap_sigchilds(void)
 725 {
 726         pid_t pid;
 727         int status;
 728
 729         while (1) {
 730                 pid = waitpid(-1, &status, WNOHANG);
 731                 if (pid <= 0)
 732                         break;
 733                 if (WIFEXITED(status))
 734                         status = WEXITSTATUS(status);
 735                 else if (WIFSIGNALED(status))
 736                         status = WTERMSIG(status) + 128;
 737                 else
 738                         status = 0;
 739                 udev_done(pid, status);
 740         }
 741 }
 742
 743 static int init_udevd_socket(void)
 744 {
 745         struct sockaddr_un saddr;
 746         const int buffersize = 16 * 1024 * 1024;
 747         socklen_t addrlen;
 748         const int feature_on = 1;
 749         int retval;
 750
 751         memset(&saddr, 0x00, sizeof(saddr));
 752         saddr.sun_family = AF_LOCAL;
 753         /* use abstract namespace for socket path */
 754         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 755         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 756
 757         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 758         if (udevd_sock == -1) {
 759                 err("error getting socket: %s", strerror(errno));
 760                 return -1;
 761         }
 762
 763         /* set receive buffersize */
 764         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 765
 766         /* the bind takes care of ensuring only one copy running */
 767         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 768         if (retval < 0) {
 769                 err("bind failed: %s", strerror(errno));
 770                 return -1;
 771         }
 772
 773         /* enable receiving of the sender credentials */
 774         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 775
 776         return 0;
 777 }
 778
 779 static int init_uevent_netlink_sock(void)
 780 {
 781         struct sockaddr_nl snl;
 782         const int buffersize = 16 * 1024 * 1024;
 783         int retval;
 784
 785         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 786         snl.nl_family = AF_NETLINK;
 787         snl.nl_pid = getpid();
 788         snl.nl_groups = 0xffffffff;
 789
 790         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 791         if (uevent_netlink_sock == -1) {
 792                 err("error getting socket: %s", strerror(errno));
 793                 return -1;
 794         }
 795
 796         /* set receive buffersize */
 797         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 798
 799         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 800         if (retval < 0) {
 801                 err("bind failed: %s", strerror(errno));
 802                 close(uevent_netlink_sock);
 803                 uevent_netlink_sock = -1;
 804                 return -1;
 805         }
 806         return 0;
 807 }
 808
 809 int main(int argc, char *argv[], char *envp[])
 810 {
 811         int retval;
 812         int fd;
 813         struct sigaction act;
 814         fd_set readfds;
 815         const char *value;
 816         int daemonize = 0;
 817         int i;
 818         int rc = 0;
 819         int maxfd;
 820
 821         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 822         fd = open("/dev/null", O_RDWR);
 823         if (fd >= 0) {
 824                 if (fd != STDIN_FILENO)
 825                         dup2(fd, STDIN_FILENO);
 826                 if (fd != STDOUT_FILENO)
 827                         dup2(fd, STDOUT_FILENO);
 828                 if (fd != STDERR_FILENO)
 829                         dup2(fd, STDERR_FILENO);
 830                 if (fd > STDERR_FILENO)
 831                         close(fd);
 832         }
 833
 834         logging_init("udevd");
 835         if (fd < 0)
 836                 err("fatal, could not open /dev/null: %s", strerror(errno));
 837
 838         udev_config_init();
 839         dbg("version %s", UDEV_VERSION);
 840
 841         if (getuid() != 0) {
 842                 err("need to be root, exit");
 843                 goto exit;
 844         }
 845
 846         /* parse commandline options */
 847         for (i = 1 ; i < argc; i++) {
 848                 char *arg = argv[i];
 849                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 850                         info("will daemonize");
 851                         daemonize = 1;
 852                 }
 853                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 854                         info("will not execute events until START_EXEC_QUEUE is received");
 855                         stop_exec_q = 1;
 856                 }
 857         }
 858
 859         /* init sockets to receive events */
 860         if (init_udevd_socket() < 0) {
 861                 if (errno == EADDRINUSE) {
 862                         err("another udevd running, exit");
 863                         rc = 1;
 864                 } else {
 865                         err("error initializing udevd socket: %s", strerror(errno));
 866                         rc = 2;
 867                 }
 868                 goto exit;
 869         }
 870
 871         if (init_uevent_netlink_sock() < 0) {
 872                 err("uevent socket not available");
 873                 rc = 3;
 874                 goto exit;
 875         }
 876
 877         /* parse the rules and keep it in memory */
 878         sysfs_init();
 879         udev_rules_init(&rules, 1);
 880
 881         if (daemonize) {
 882                 pid_t pid;
 883
 884                 pid = fork();
 885                 switch (pid) {
 886                 case 0:
 887                         dbg("daemonized fork running");
 888                         break;
 889                 case -1:
 890                         err("fork of daemon failed: %s", strerror(errno));
 891                         rc = 4;
 892                         goto exit;
 893                 default:
 894                         dbg("child [%u] running, parent exits", pid);
 895                         goto exit;
 896                 }
 897         }
 898
 899         /* set scheduling priority for the daemon */
 900         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 901
 902         chdir("/");
 903         umask(022);
 904
 905         /* become session leader */
 906         sid = setsid();
 907         dbg("our session is %d", sid);
 908
 909         /* OOM_DISABLE == -17 */
 910         fd = open("/proc/self/oom_adj", O_RDWR);
 911         if (fd < 0)
 912                 err("error disabling OOM: %s", strerror(errno));
 913         else {
 914                 write(fd, "-17", 3);
 915                 close(fd);
 916         }
 917
 918         /* setup signal handler pipe */
 919         retval = pipe(signal_pipe);
 920         if (retval < 0) {
 921                 err("error getting pipes: %s", strerror(errno));
 922                 goto exit;
 923         }
 924
 925         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 926         if (retval < 0) {
 927                 err("error fcntl on read pipe: %s", strerror(errno));
 928                 goto exit;
 929         }
 930         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 931         if (retval < 0) {
 932                 err("error fcntl on read pipe: %s", strerror(errno));
 933                 goto exit;
 934         }
 935
 936         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 937         if (retval < 0) {
 938                 err("error fcntl on write pipe: %s", strerror(errno));
 939                 goto exit;
 940         }
 941         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 942         if (retval < 0) {
 943                 err("error fcntl on write pipe: %s", strerror(errno));
 944                 goto exit;
 945         }
 946
 947         /* set signal handlers */
 948         memset(&act, 0x00, sizeof(struct sigaction));
 949         act.sa_handler = (void (*)(int)) sig_handler;
 950         sigemptyset(&act.sa_mask);
 951         act.sa_flags = SA_RESTART;
 952         sigaction(SIGINT, &act, NULL);
 953         sigaction(SIGTERM, &act, NULL);
 954         sigaction(SIGCHLD, &act, NULL);
 955         sigaction(SIGHUP, &act, NULL);
 956
 957         /* watch rules directory */
 958         inotify_fd = inotify_init();
 959         if (inotify_fd > 0)
 960                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 961
 962         /* maximum limit of forked childs */
 963         value = getenv("UDEVD_MAX_CHILDS");
 964         if (value)
 965                 max_childs = strtoul(value, NULL, 10);
 966         else
 967                 max_childs = UDEVD_MAX_CHILDS;
 968         info("initialize max_childs to %u", max_childs);
 969
 970         /* start to throttle forking if maximum number of _running_ childs is reached */
 971         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 972         if (value)
 973                 max_childs_running = strtoull(value, NULL, 10);
 974         else
 975                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 976         info("initialize max_childs_running to %u", max_childs_running);
 977
 978         /* clear environment for forked event processes */
 979         clearenv();
 980
 981         /* export log_priority , as called programs may want to follow that setting */
 982         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 983         putenv(udev_log);
 984
 985         maxfd = udevd_sock;
 986         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
 987         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
 988         maxfd = UDEV_MAX(maxfd, inotify_fd);
 989
 990         while (!udev_exit) {
 991                 struct uevent_msg *msg;
 992                 int fdcount;
 993
 994                 FD_ZERO(&readfds);
 995                 FD_SET(signal_pipe[READ_END], &readfds);
 996                 FD_SET(udevd_sock, &readfds);
 997                 FD_SET(uevent_netlink_sock, &readfds);
 998                 if (inotify_fd > 0)
 999                         FD_SET(inotify_fd, &readfds);
1000
1001                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1002                 if (fdcount < 0) {
1003                         if (errno != EINTR)
1004                                 err("error in select: %s", strerror(errno));
1005                         continue;
1006                 }
1007
1008                 /* get user socket message */
1009                 if (FD_ISSET(udevd_sock, &readfds)) {
1010                         msg = get_udevd_msg();
1011                         if (msg)
1012                                 msg_queue_insert(msg);
1013                 }
1014
1015                 /* get kernel netlink message */
1016                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1017                         msg = get_netlink_msg();
1018                         if (msg)
1019                                 msg_queue_insert(msg);
1020                 }
1021
1022                 /* received a signal, clear our notification pipe */
1023                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1024                         char buf[256];
1025
1026                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1027                 }
1028
1029                 /* rules directory inotify watch */
1030                 if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
1031                         int nbytes;
1032
1033                         /* discard all possible events, we can just reload the config */
1034                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1035                                 char *buf;
1036
1037                                 reload_config = 1;
1038                                 buf = malloc(nbytes);
1039                                 if (!buf) {
1040                                         err("error getting buffer for inotify, disable watching");
1041                                         close(inotify_fd);
1042                                         inotify_fd = -1;
1043                                 }
1044                                 read(inotify_fd, buf, nbytes);
1045                                 free(buf);
1046                         }
1047                 }
1048
1049                 /* rules changed, set by inotify or a signal*/
1050                 if (reload_config) {
1051                         reload_config = 0;
1052                         udev_rules_cleanup(&rules);
1053                         udev_rules_init(&rules, 1);
1054                 }
1055
1056                 /* forked child has returned */
1057                 if (sigchilds_waiting) {
1058                         sigchilds_waiting = 0;
1059                         reap_sigchilds();
1060                 }
1061
1062                 if (run_exec_q) {
1063                         run_exec_q = 0;
1064                         if (!stop_exec_q)
1065                                 msg_queue_manager();
1066                 }
1067         }
1068
1069 exit:
1070         udev_rules_cleanup(&rules);
1071         sysfs_cleanup();
1072
1073         if (signal_pipe[READ_END] > 0)
1074                 close(signal_pipe[READ_END]);
1075         if (signal_pipe[WRITE_END] > 0)
1076                 close(signal_pipe[WRITE_END]);
1077
1078         if (udevd_sock > 0)
1079                 close(udevd_sock);
1080         if (inotify_fd > 0)
1081                 close(inotify_fd);
1082         if (uevent_netlink_sock > 0)
1083                 close(uevent_netlink_sock);
1084
1085         logging_close();
1086
1087         return rc;
1088 }