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:")], udev->dev->devpath, udev->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         char filename[PATH_SIZE];
 283         int fd;
 284
 285         msg->queue_time = time(NULL);
 286
 287         strlcpy(filename, udev_root, sizeof(filename));
 288         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 289         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 290         if (fd >= 0) {
 291                 char str[32];
 292                 int len;
 293
 294                 len = sprintf(str, "%llu\n", msg->seqnum);
 295                 write(fd, str, len);
 296                 close(fd);
 297         }
 298
 299         export_event_state(msg, EVENT_QUEUED);
 300
 301         /* run all events with a timeout set immediately */
 302         if (msg->timeout != 0) {
 303                 list_add_tail(&msg->node, &running_list);
 304                 udev_event_run(msg);
 305                 return;
 306         }
 307
 308         list_add_tail(&msg->node, &exec_list);
 309         run_exec_q = 1;
 310 }
 311
 312 /* runs event and removes event from run queue when finished */
 313 static int running_processes(void)
 314 {
 315         int f;
 316         static char buf[4096];
 317         int len;
 318         int running;
 319         const char *pos;
 320
 321         f = open("/proc/stat", O_RDONLY);
 322         if (f == -1)
 323                 return -1;
 324
 325         len = read(f, buf, sizeof(buf)-1);
 326         close(f);
 327
 328         if (len <= 0)
 329                 return -1;
 330         else
 331                 buf[len] = '\0';
 332
 333         pos = strstr(buf, "procs_running ");
 334         if (pos == NULL)
 335                 return -1;
 336
 337         if (sscanf(pos, "procs_running %u", &running) != 1)
 338                 return -1;
 339
 340         return running;
 341 }
 342
 343 /* return the number of process es in our session, count only until limit */
 344 static int running_processes_in_session(pid_t session, int limit)
 345 {
 346         DIR *dir;
 347         struct dirent *dent;
 348         int running = 0;
 349
 350         dir = opendir("/proc");
 351         if (!dir)
 352                 return -1;
 353
 354         /* read process info from /proc */
 355         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 356                 int f;
 357                 char procdir[64];
 358                 char line[256];
 359                 const char *pos;
 360                 char state;
 361                 pid_t ppid, pgrp, sess;
 362                 int len;
 363
 364                 if (!isdigit(dent->d_name[0]))
 365                         continue;
 366
 367                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 368                 procdir[sizeof(procdir)-1] = '\0';
 369
 370                 f = open(procdir, O_RDONLY);
 371                 if (f == -1)
 372                         continue;
 373
 374                 len = read(f, line, sizeof(line)-1);
 375                 close(f);
 376
 377                 if (len <= 0)
 378                         continue;
 379                 else
 380                         line[len] = '\0';
 381
 382                 /* skip ugly program name */
 383                 pos = strrchr(line, ')') + 2;
 384                 if (pos == NULL)
 385                         continue;
 386
 387                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 388                         continue;
 389
 390                 /* count only processes in our session */
 391                 if (sess != session)
 392                         continue;
 393
 394                 /* count only running, no sleeping processes */
 395                 if (state != 'R')
 396                         continue;
 397
 398                 running++;
 399                 if (limit > 0 && running >= limit)
 400                         break;
 401         }
 402         closedir(dir);
 403
 404         return running;
 405 }
 406
 407 static int compare_devpath(const char *running, const char *waiting)
 408 {
 409         int i;
 410
 411         for (i = 0; i < PATH_SIZE; i++) {
 412                 /* identical device event found */
 413                 if (running[i] == '\0' && waiting[i] == '\0')
 414                         return 1;
 415
 416                 /* parent device event found */
 417                 if (running[i] == '\0' && waiting[i] == '/')
 418                         return 2;
 419
 420                 /* child device event found */
 421                 if (running[i] == '/' && waiting[i] == '\0')
 422                         return 3;
 423
 424                 /* no matching event */
 425                 if (running[i] != waiting[i])
 426                         break;
 427         }
 428
 429         return 0;
 430 }
 431
 432 /* returns still running task for the same device, its parent or its physical device */
 433 static int running_with_devpath(struct uevent_msg *msg, int limit)
 434 {
 435         struct uevent_msg *loop_msg;
 436         int childs_count = 0;
 437
 438         list_for_each_entry(loop_msg, &running_list, node) {
 439                 if (limit && childs_count++ > limit) {
 440                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 441                         return 1;
 442                 }
 443
 444                 /* return running parent/child device event */
 445                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 446                         dbg("%llu, child device event still running %llu (%s)",
 447                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 448                         return 2;
 449                 }
 450
 451                 /* return running physical device event */
 452                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 453                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 454                                 dbg("%llu, physical device event still running %llu (%s)",
 455                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 456                                 return 3;
 457                         }
 458         }
 459
 460         return 0;
 461 }
 462
 463 /* exec queue management routine executes the events and serializes events in the same sequence */
 464 static void msg_queue_manager(void)
 465 {
 466         struct uevent_msg *loop_msg;
 467         struct uevent_msg *tmp_msg;
 468         int running;
 469
 470         if (list_empty(&exec_list))
 471                 return;
 472
 473         running = running_processes();
 474         dbg("%d processes runnning on system", running);
 475         if (running < 0)
 476                 running = max_childs_running;
 477
 478         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 479                 /* check running processes in our session and possibly throttle */
 480                 if (running >= max_childs_running) {
 481                         running = running_processes_in_session(sid, max_childs_running+10);
 482                         dbg("at least %d processes running in session", running);
 483                         if (running >= max_childs_running) {
 484                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 485                                 return;
 486                         }
 487                 }
 488
 489                 /* don't run two processes for the same devpath and wait for the parent*/
 490                 if (running_with_devpath(loop_msg, max_childs)) {
 491                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 492                         continue;
 493                 }
 494
 495                 /* move event to run list */
 496                 list_move_tail(&loop_msg->node, &running_list);
 497                 udev_event_run(loop_msg);
 498                 running++;
 499                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 500         }
 501 }
 502
 503 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 504 {
 505         int bufpos;
 506         int i;
 507         struct uevent_msg *msg;
 508         int major = 0;
 509         int minor = 0;
 510
 511         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 512         if (msg == NULL)
 513                 return NULL;
 514         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 515
 516         /* copy environment buffer and reconstruct envp */
 517         memcpy(msg->envbuf, buf, buf_size);
 518         bufpos = 0;
 519         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 520                 int keylen;
 521                 char *key;
 522
 523                 key = &msg->envbuf[bufpos];
 524                 keylen = strlen(key);
 525                 msg->envp[i] = key;
 526                 bufpos += keylen + 1;
 527                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 528
 529                 /* remember some keys for further processing */
 530                 if (strncmp(key, "ACTION=", 7) == 0)
 531                         msg->action = &key[7];
 532                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 533                         msg->devpath = &key[8];
 534                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 535                         msg->subsystem = &key[10];
 536                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 537                         msg->seqnum = strtoull(&key[7], NULL, 10);
 538                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 539                         msg->physdevpath = &key[12];
 540                 else if (strncmp(key, "MAJOR=", 6) == 0)
 541                         major = strtoull(&key[6], NULL, 10);
 542                 else if (strncmp(key, "MINOR=", 6) == 0)
 543                         minor = strtoull(&key[6], NULL, 10);
 544                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 545                         msg->timeout = strtoull(&key[8], NULL, 10);
 546         }
 547         msg->devt = makedev(major, minor);
 548         msg->envp[i++] = "UDEVD_EVENT=1";
 549         msg->envp[i] = NULL;
 550
 551         if (msg->devpath == NULL || msg->action == NULL) {
 552                 info("DEVPATH or ACTION missing, ignore message");
 553                 free(msg);
 554                 return NULL;
 555         }
 556         return msg;
 557 }
 558
 559 /* receive the udevd message from userspace */
 560 static struct uevent_msg *get_udevd_msg(void)
 561 {
 562         static struct udevd_msg usend_msg;
 563         struct uevent_msg *msg;
 564         ssize_t size;
 565         struct msghdr smsg;
 566         struct cmsghdr *cmsg;
 567         struct iovec iov;
 568         struct ucred *cred;
 569         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 570         int envbuf_size;
 571         int *intval;
 572
 573         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 574         iov.iov_base = &usend_msg;
 575         iov.iov_len = sizeof(struct udevd_msg);
 576
 577         memset(&smsg, 0x00, sizeof(struct msghdr));
 578         smsg.msg_iov = &iov;
 579         smsg.msg_iovlen = 1;
 580         smsg.msg_control = cred_msg;
 581         smsg.msg_controllen = sizeof(cred_msg);
 582
 583         size = recvmsg(udevd_sock, &smsg, 0);
 584         if (size <  0) {
 585                 if (errno != EINTR)
 586                         err("unable to receive user udevd message: %s", strerror(errno));
 587                 return NULL;
 588         }
 589         cmsg = CMSG_FIRSTHDR(&smsg);
 590         cred = (struct ucred *) CMSG_DATA(cmsg);
 591
 592         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 593                 err("no sender credentials received, message ignored");
 594                 return NULL;
 595         }
 596
 597         if (cred->uid != 0) {
 598                 err("sender uid=%i, message ignored", cred->uid);
 599                 return NULL;
 600         }
 601
 602         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 603                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 604                 return NULL;
 605         }
 606
 607         switch (usend_msg.type) {
 608         case UDEVD_UEVENT_UDEVSEND:
 609                 info("udevd event message received");
 610                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 611                 dbg("envbuf_size=%i", envbuf_size);
 612                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 613                 if (msg == NULL)
 614                         return NULL;
 615                 msg->type = usend_msg.type;
 616                 return msg;
 617         case UDEVD_STOP_EXEC_QUEUE:
 618                 info("udevd message (STOP_EXEC_QUEUE) received");
 619                 stop_exec_q = 1;
 620                 break;
 621         case UDEVD_START_EXEC_QUEUE:
 622                 info("udevd message (START_EXEC_QUEUE) received");
 623                 stop_exec_q = 0;
 624                 msg_queue_manager();
 625                 break;
 626         case UDEVD_SET_LOG_LEVEL:
 627                 intval = (int *) usend_msg.envbuf;
 628                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 629                 udev_log_priority = *intval;
 630                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 631                 putenv(udev_log);
 632                 break;
 633         case UDEVD_SET_MAX_CHILDS:
 634                 intval = (int *) usend_msg.envbuf;
 635                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 636                 max_childs = *intval;
 637                 break;
 638         case UDEVD_RELOAD_RULES:
 639                 info("udevd message (RELOAD_RULES) received");
 640                 reload_config = 1;
 641                 break;
 642         default:
 643                 dbg("unknown message type");
 644         }
 645         return NULL;
 646 }
 647
 648 /* receive the kernel user event message and do some sanity checks */
 649 static struct uevent_msg *get_netlink_msg(void)
 650 {
 651         struct uevent_msg *msg;
 652         int bufpos;
 653         ssize_t size;
 654         static char buffer[UEVENT_BUFFER_SIZE+512];
 655         char *pos;
 656
 657         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 658         if (size <  0) {
 659                 if (errno != EINTR)
 660                         err("unable to receive kernel netlink message: %s", strerror(errno));
 661                 return NULL;
 662         }
 663
 664         if ((size_t)size > sizeof(buffer)-1)
 665                 size = sizeof(buffer)-1;
 666         buffer[size] = '\0';
 667         dbg("uevent_size=%zi", size);
 668
 669         /* start of event payload */
 670         bufpos = strlen(buffer)+1;
 671         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 672         if (msg == NULL)
 673                 return NULL;
 674         msg->type = UDEVD_UEVENT_NETLINK;
 675
 676         /* validate message */
 677         pos = strchr(buffer, '@');
 678         if (pos == NULL) {
 679                 err("invalid uevent '%s'", buffer);
 680                 free(msg);
 681                 return NULL;
 682         }
 683         pos[0] = '\0';
 684
 685         if (msg->action == NULL) {
 686                 info("no ACTION in payload found, skip event '%s'", buffer);
 687                 free(msg);
 688                 return NULL;
 689         }
 690
 691         if (strcmp(msg->action, buffer) != 0) {
 692                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 693                 free(msg);
 694                 return NULL;
 695         }
 696
 697         return msg;
 698 }
 699
 700 static void asmlinkage sig_handler(int signum)
 701 {
 702         switch (signum) {
 703                 case SIGINT:
 704                 case SIGTERM:
 705                         udev_exit = 1;
 706                         break;
 707                 case SIGCHLD:
 708                         /* set flag, then write to pipe if needed */
 709                         sigchilds_waiting = 1;
 710                         break;
 711                 case SIGHUP:
 712                         reload_config = 1;
 713                         break;
 714         }
 715
 716         /* write to pipe, which will wakeup select() in our mainloop */
 717         write(signal_pipe[WRITE_END], "", 1);
 718 }
 719
 720 static void udev_done(int pid, int exitstatus)
 721 {
 722         /* find msg associated with pid and delete it */
 723         struct uevent_msg *msg;
 724
 725         list_for_each_entry(msg, &running_list, node) {
 726                 if (msg->pid == pid) {
 727                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 728                              exitstatus, time(NULL) - msg->queue_time);
 729                         msg->exitstatus = exitstatus;
 730                         msg_queue_delete(msg);
 731
 732                         /* there may be events waiting with the same devpath */
 733                         run_exec_q = 1;
 734                         return;
 735                 }
 736         }
 737 }
 738
 739 static void reap_sigchilds(void)
 740 {
 741         pid_t pid;
 742         int status;
 743
 744         while (1) {
 745                 pid = waitpid(-1, &status, WNOHANG);
 746                 if (pid <= 0)
 747                         break;
 748                 if (WIFEXITED(status))
 749                         status = WEXITSTATUS(status);
 750                 else if (WIFSIGNALED(status))
 751                         status = WTERMSIG(status) + 128;
 752                 else
 753                         status = 0;
 754                 udev_done(pid, status);
 755         }
 756 }
 757
 758 static int init_udevd_socket(void)
 759 {
 760         struct sockaddr_un saddr;
 761         const int buffersize = 16 * 1024 * 1024;
 762         socklen_t addrlen;
 763         const int feature_on = 1;
 764         int retval;
 765
 766         memset(&saddr, 0x00, sizeof(saddr));
 767         saddr.sun_family = AF_LOCAL;
 768         /* use abstract namespace for socket path */
 769         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 770         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 771
 772         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 773         if (udevd_sock == -1) {
 774                 err("error getting socket: %s", strerror(errno));
 775                 return -1;
 776         }
 777
 778         /* set receive buffersize */
 779         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 780
 781         /* the bind takes care of ensuring only one copy running */
 782         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 783         if (retval < 0) {
 784                 err("bind failed: %s", strerror(errno));
 785                 return -1;
 786         }
 787
 788         /* enable receiving of the sender credentials */
 789         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 790
 791         return 0;
 792 }
 793
 794 static int init_uevent_netlink_sock(void)
 795 {
 796         struct sockaddr_nl snl;
 797         const int buffersize = 16 * 1024 * 1024;
 798         int retval;
 799
 800         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 801         snl.nl_family = AF_NETLINK;
 802         snl.nl_pid = getpid();
 803         snl.nl_groups = 0xffffffff;
 804
 805         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 806         if (uevent_netlink_sock == -1) {
 807                 err("error getting socket: %s", strerror(errno));
 808                 return -1;
 809         }
 810
 811         /* set receive buffersize */
 812         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 813
 814         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 815         if (retval < 0) {
 816                 err("bind failed: %s", strerror(errno));
 817                 close(uevent_netlink_sock);
 818                 uevent_netlink_sock = -1;
 819                 return -1;
 820         }
 821         return 0;
 822 }
 823
 824 static void export_initial_seqnum(void)
 825 {
 826         char filename[PATH_SIZE];
 827         int fd;
 828         char seqnum[32];
 829         ssize_t len = 0;
 830
 831         strlcpy(filename, sysfs_path, sizeof(filename));
 832         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 833         fd = open(filename, O_RDONLY);
 834         if (fd >= 0) {
 835                 len = read(fd, seqnum, sizeof(seqnum)-1);
 836                 close(fd);
 837         }
 838         if (len <= 0) {
 839                 strcpy(seqnum, "0\n");
 840                 len = 3;
 841         }
 842         strlcpy(filename, udev_root, sizeof(filename));
 843         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 844         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 845         if (fd >= 0) {
 846                 write(fd, seqnum, len);
 847                 close(fd);
 848         }
 849 }
 850
 851 int main(int argc, char *argv[], char *envp[])
 852 {
 853         int retval;
 854         int fd;
 855         struct sigaction act;
 856         fd_set readfds;
 857         const char *value;
 858         int daemonize = 0;
 859         int i;
 860         int rc = 0;
 861         int maxfd;
 862
 863         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 864         fd = open("/dev/null", O_RDWR);
 865         if (fd >= 0) {
 866                 if (fd != STDIN_FILENO)
 867                         dup2(fd, STDIN_FILENO);
 868                 if (fd != STDOUT_FILENO)
 869                         dup2(fd, STDOUT_FILENO);
 870                 if (fd != STDERR_FILENO)
 871                         dup2(fd, STDERR_FILENO);
 872                 if (fd > STDERR_FILENO)
 873                         close(fd);
 874         }
 875
 876         logging_init("udevd");
 877         if (fd < 0)
 878                 err("fatal, could not open /dev/null: %s", strerror(errno));
 879
 880         udev_config_init();
 881         dbg("version %s", UDEV_VERSION);
 882
 883         if (getuid() != 0) {
 884                 err("need to be root, exit");
 885                 goto exit;
 886         }
 887
 888         /* parse commandline options */
 889         for (i = 1 ; i < argc; i++) {
 890                 char *arg = argv[i];
 891                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 892                         info("will daemonize");
 893                         daemonize = 1;
 894                 }
 895                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 896                         info("will not execute events until START_EXEC_QUEUE is received");
 897                         stop_exec_q = 1;
 898                 }
 899         }
 900
 901         /* init sockets to receive events */
 902         if (init_udevd_socket() < 0) {
 903                 if (errno == EADDRINUSE) {
 904                         err("another udevd running, exit");
 905                         rc = 1;
 906                 } else {
 907                         err("error initializing udevd socket: %s", strerror(errno));
 908                         rc = 2;
 909                 }
 910                 goto exit;
 911         }
 912
 913         if (init_uevent_netlink_sock() < 0) {
 914                 err("uevent socket not available");
 915                 rc = 3;
 916                 goto exit;
 917         }
 918
 919         /* parse the rules and keep it in memory */
 920         sysfs_init();
 921         udev_rules_init(&rules, 1);
 922
 923         export_initial_seqnum();
 924
 925         if (daemonize) {
 926                 pid_t pid;
 927
 928                 pid = fork();
 929                 switch (pid) {
 930                 case 0:
 931                         dbg("daemonized fork running");
 932                         break;
 933                 case -1:
 934                         err("fork of daemon failed: %s", strerror(errno));
 935                         rc = 4;
 936                         goto exit;
 937                 default:
 938                         dbg("child [%u] running, parent exits", pid);
 939                         goto exit;
 940                 }
 941         }
 942
 943         /* set scheduling priority for the daemon */
 944         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 945
 946         chdir("/");
 947         umask(022);
 948
 949         /* become session leader */
 950         sid = setsid();
 951         dbg("our session is %d", sid);
 952
 953         /* OOM_DISABLE == -17 */
 954         fd = open("/proc/self/oom_adj", O_RDWR);
 955         if (fd < 0)
 956                 err("error disabling OOM: %s", strerror(errno));
 957         else {
 958                 write(fd, "-17", 3);
 959                 close(fd);
 960         }
 961
 962         /* setup signal handler pipe */
 963         retval = pipe(signal_pipe);
 964         if (retval < 0) {
 965                 err("error getting pipes: %s", strerror(errno));
 966                 goto exit;
 967         }
 968
 969         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 970         if (retval < 0) {
 971                 err("error fcntl on read pipe: %s", strerror(errno));
 972                 goto exit;
 973         }
 974         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 975         if (retval < 0) {
 976                 err("error fcntl on read pipe: %s", strerror(errno));
 977                 goto exit;
 978         }
 979
 980         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 981         if (retval < 0) {
 982                 err("error fcntl on write pipe: %s", strerror(errno));
 983                 goto exit;
 984         }
 985         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 986         if (retval < 0) {
 987                 err("error fcntl on write pipe: %s", strerror(errno));
 988                 goto exit;
 989         }
 990
 991         /* set signal handlers */
 992         memset(&act, 0x00, sizeof(struct sigaction));
 993         act.sa_handler = (void (*)(int)) sig_handler;
 994         sigemptyset(&act.sa_mask);
 995         act.sa_flags = SA_RESTART;
 996         sigaction(SIGINT, &act, NULL);
 997         sigaction(SIGTERM, &act, NULL);
 998         sigaction(SIGCHLD, &act, NULL);
 999         sigaction(SIGHUP, &act, NULL);
1000
1001         /* watch rules directory */
1002         inotify_fd = inotify_init();
1003         if (inotify_fd >= 0)
1004                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1005         else if (errno == ENOSYS)
1006                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1007         else
1008                 err("inotify_init failed: %s", strerror(errno));
1009
1010         /* maximum limit of forked childs */
1011         value = getenv("UDEVD_MAX_CHILDS");
1012         if (value)
1013                 max_childs = strtoul(value, NULL, 10);
1014         else
1015                 max_childs = UDEVD_MAX_CHILDS;
1016         info("initialize max_childs to %u", max_childs);
1017
1018         /* start to throttle forking if maximum number of _running_ childs is reached */
1019         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1020         if (value)
1021                 max_childs_running = strtoull(value, NULL, 10);
1022         else
1023                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1024         info("initialize max_childs_running to %u", max_childs_running);
1025
1026         /* clear environment for forked event processes */
1027         clearenv();
1028
1029         /* export log_priority , as called programs may want to follow that setting */
1030         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1031         putenv(udev_log);
1032
1033         maxfd = udevd_sock;
1034         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1035         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1036         maxfd = UDEV_MAX(maxfd, inotify_fd);
1037
1038         while (!udev_exit) {
1039                 struct uevent_msg *msg;
1040                 int fdcount;
1041
1042                 FD_ZERO(&readfds);
1043                 FD_SET(signal_pipe[READ_END], &readfds);
1044                 FD_SET(udevd_sock, &readfds);
1045                 FD_SET(uevent_netlink_sock, &readfds);
1046                 if (inotify_fd >= 0)
1047                         FD_SET(inotify_fd, &readfds);
1048
1049                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1050                 if (fdcount < 0) {
1051                         if (errno != EINTR)
1052                                 err("error in select: %s", strerror(errno));
1053                         continue;
1054                 }
1055
1056                 /* get user socket message */
1057                 if (FD_ISSET(udevd_sock, &readfds)) {
1058                         msg = get_udevd_msg();
1059                         if (msg)
1060                                 msg_queue_insert(msg);
1061                 }
1062
1063                 /* get kernel netlink message */
1064                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1065                         msg = get_netlink_msg();
1066                         if (msg)
1067                                 msg_queue_insert(msg);
1068                 }
1069
1070                 /* received a signal, clear our notification pipe */
1071                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1072                         char buf[256];
1073
1074                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1075                 }
1076
1077                 /* rules directory inotify watch */
1078                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1079                         int nbytes;
1080
1081                         /* discard all possible events, we can just reload the config */
1082                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1083                                 char *buf;
1084
1085                                 reload_config = 1;
1086                                 buf = malloc(nbytes);
1087                                 if (!buf) {
1088                                         err("error getting buffer for inotify, disable watching");
1089                                         close(inotify_fd);
1090                                         inotify_fd = -1;
1091                                 }
1092                                 read(inotify_fd, buf, nbytes);
1093                                 free(buf);
1094                         }
1095                 }
1096
1097                 /* rules changed, set by inotify or a signal*/
1098                 if (reload_config) {
1099                         reload_config = 0;
1100                         udev_rules_cleanup(&rules);
1101                         udev_rules_init(&rules, 1);
1102                 }
1103
1104                 /* forked child has returned */
1105                 if (sigchilds_waiting) {
1106                         sigchilds_waiting = 0;
1107                         reap_sigchilds();
1108                 }
1109
1110                 if (run_exec_q) {
1111                         run_exec_q = 0;
1112                         if (!stop_exec_q)
1113                                 msg_queue_manager();
1114                 }
1115         }
1116
1117 exit:
1118         udev_rules_cleanup(&rules);
1119         sysfs_cleanup();
1120
1121         if (signal_pipe[READ_END] >= 0)
1122                 close(signal_pipe[READ_END]);
1123         if (signal_pipe[WRITE_END] >= 0)
1124                 close(signal_pipe[WRITE_END]);
1125
1126         if (udevd_sock >= 0)
1127                 close(udevd_sock);
1128         if (inotify_fd >= 0)
1129                 close(inotify_fd);
1130         if (uevent_netlink_sock >= 0)
1131                 close(uevent_netlink_sock);
1132
1133         logging_close();
1134
1135         return rc;
1136 }