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