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