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