udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   6  *
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stddef.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <time.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47 #include "udevd.h"
  48
  49 static struct udev_rules rules;
  50 static int udevd_sock;
  51 static int uevent_netlink_sock;
  52 static int inotify_fd;
  53 static pid_t sid;
  54
  55 static int signal_pipe[2] = {-1, -1};
  56 static volatile int sigchilds_waiting;
  57 static volatile int udev_exit;
  58 static volatile int reload_config;
  59 static int run_exec_q;
  60 static int stop_exec_q;
  61 static int max_childs;
  62 static int max_childs_running;
  63 static char udev_log[32];
  64
  65 static LIST_HEAD(exec_list);
  66 static LIST_HEAD(running_list);
  67
  68
  69 #ifdef USE_LOG
  70 void log_message(int priority, const char *format, ...)
  71 {
  72         va_list args;
  73
  74         if (priority > udev_log_priority)
  75                 return;
  76
  77         va_start(args, format);
  78         vsyslog(priority, format, args);
  79         va_end(args);
  80 }
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* trigger timeout to prevent hanging processes */
 104         alarm(UDEV_ALARM_TIMEOUT);
 105
 106         /* reconstruct event environment from message */
 107         for (i = 0; msg->envp[i]; i++)
 108                 putenv(msg->envp[i]);
 109
 110         udev = udev_device_init();
 111         if (udev == NULL)
 112                 return -1;
 113         strlcpy(udev->action, msg->action, sizeof(udev->action));
 114         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
 115         udev->devt = msg->devt;
 116
 117         retval = udev_device_event(&rules, udev);
 118
 119         /* run programs collected by RUN-key*/
 120         if (retval == 0 && !udev->ignore_device && udev_run) {
 121                 struct name_entry *name_loop;
 122
 123                 dbg("executing run list");
 124                 list_for_each_entry(name_loop, &udev->run_list, node) {
 125                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 126                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
 127                         else {
 128                                 char program[PATH_SIZE];
 129
 130                                 strlcpy(program, name_loop->name, sizeof(program));
 131                                 udev_rules_apply_format(udev, program, sizeof(program));
 132                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 133                                                 (udev_log_priority >= LOG_INFO)))
 134                                         retval = -1;
 135                         }
 136                 }
 137         }
 138
 139         udev_device_cleanup(udev);
 140         return retval;
 141 }
 142
 143 enum event_state {
 144         EVENT_QUEUED,
 145         EVENT_FINISHED,
 146         EVENT_FAILED,
 147 };
 148
 149 static void export_event_state(struct uevent_msg *msg, enum event_state state)
 150 {
 151         char filename[PATH_SIZE];
 152         char filename_failed[PATH_SIZE];
 153         char target[PATH_SIZE];
 154         size_t start, end, i;
 155         struct uevent_msg *loop_msg;
 156
 157         /* add location of queue files */
 158         strlcpy(filename, udev_root, sizeof(filename));
 159         strlcat(filename, "/", sizeof(filename));
 160         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 161         end = strlcat(filename, msg->devpath, sizeof(filename));
 162         if (end > sizeof(filename))
 163                 end = sizeof(filename);
 164
 165         /* replace '/' to transform path into a filename */
 166         for (i = start+1; i < end; i++)
 167                 if (filename[i] == '/')
 168                         filename[i] = PATH_TO_NAME_CHAR;
 169
 170         /* add location of failed files */
 171         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 172         strlcat(filename_failed, "/", sizeof(filename_failed));
 173         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 174         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 175         if (end > sizeof(filename_failed))
 176                 end = sizeof(filename_failed);
 177
 178         /* replace '/' to transform path into a filename */
 179         for (i = start+1; i < end; i++)
 180                 if (filename_failed[i] == '/')
 181                         filename_failed[i] = PATH_TO_NAME_CHAR;
 182
 183         switch (state) {
 184         case EVENT_QUEUED:
 185                 unlink(filename_failed);
 186                 delete_path(filename_failed);
 187
 188                 strlcpy(target, sysfs_path, sizeof(target));
 189                 strlcat(target, msg->devpath, sizeof(target));
 190                 create_path(filename);
 191                 symlink(target, filename);
 192                 return;
 193         case EVENT_FINISHED:
 194         case EVENT_FAILED:
 195                 unlink(filename_failed);
 196                 delete_path(filename_failed);
 197
 198                 /* don't remove, if events for the same path are still pending */
 199                 list_for_each_entry(loop_msg, &running_list, node)
 200                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 201                                 return;
 202
 203                 /* move failed events to the failed directory */
 204                 if (state == EVENT_FAILED) {
 205                         create_path(filename_failed);
 206                         rename(filename, filename_failed);
 207                 } else {
 208                         unlink(filename);
 209                 }
 210
 211                 /* clean up the queue directory */
 212                 delete_path(filename);
 213
 214                 return;
 215         }
 216 }
 217
 218 static void msg_queue_delete(struct uevent_msg *msg)
 219 {
 220         list_del(&msg->node);
 221
 222         /* mark as failed, if add event returns non-zero */
 223         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 224                 export_event_state(msg, EVENT_FAILED);
 225         else
 226                 export_event_state(msg, EVENT_FINISHED);
 227
 228         free(msg);
 229 }
 230
 231 static void udev_event_run(struct uevent_msg *msg)
 232 {
 233         pid_t pid;
 234         int retval;
 235
 236         pid = fork();
 237         switch (pid) {
 238         case 0:
 239                 /* child */
 240                 close(uevent_netlink_sock);
 241                 close(udevd_sock);
 242                 if (inotify_fd > 0)
 243                         close(inotify_fd);
 244                 close(signal_pipe[READ_END]);
 245                 close(signal_pipe[WRITE_END]);
 246                 logging_close();
 247
 248                 logging_init("udevd-event");
 249                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 250                 retval = udev_event_process(msg);
 251                 info("seq %llu finished", msg->seqnum);
 252
 253                 logging_close();
 254                 if (retval)
 255                         exit(1);
 256                 exit(0);
 257         case -1:
 258                 err("fork of child failed: %s", strerror(errno));
 259                 msg_queue_delete(msg);
 260                 break;
 261         default:
 262                 /* get SIGCHLD in main loop */
 263                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 264                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 265                 msg->pid = pid;
 266         }
 267 }
 268
 269 static void msg_queue_insert(struct uevent_msg *msg)
 270 {
 271         msg->queue_time = time(NULL);
 272
 273         export_event_state(msg, EVENT_QUEUED);
 274
 275         /* run all events with a timeout set immediately */
 276         if (msg->timeout != 0) {
 277                 list_add_tail(&msg->node, &running_list);
 278                 udev_event_run(msg);
 279                 return;
 280         }
 281
 282         list_add_tail(&msg->node, &exec_list);
 283         run_exec_q = 1;
 284 }
 285
 286 /* runs event and removes event from run queue when finished */
 287 static int running_processes(void)
 288 {
 289         int f;
 290         static char buf[4096];
 291         int len;
 292         int running;
 293         const char *pos;
 294
 295         f = open("/proc/stat", O_RDONLY);
 296         if (f == -1)
 297                 return -1;
 298
 299         len = read(f, buf, sizeof(buf)-1);
 300         close(f);
 301
 302         if (len <= 0)
 303                 return -1;
 304         else
 305                 buf[len] = '\0';
 306
 307         pos = strstr(buf, "procs_running ");
 308         if (pos == NULL)
 309                 return -1;
 310
 311         if (sscanf(pos, "procs_running %u", &running) != 1)
 312                 return -1;
 313
 314         return running;
 315 }
 316
 317 /* return the number of process es in our session, count only until limit */
 318 static int running_processes_in_session(pid_t session, int limit)
 319 {
 320         DIR *dir;
 321         struct dirent *dent;
 322         int running = 0;
 323
 324         dir = opendir("/proc");
 325         if (!dir)
 326                 return -1;
 327
 328         /* read process info from /proc */
 329         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 330                 int f;
 331                 char procdir[64];
 332                 char line[256];
 333                 const char *pos;
 334                 char state;
 335                 pid_t ppid, pgrp, sess;
 336                 int len;
 337
 338                 if (!isdigit(dent->d_name[0]))
 339                         continue;
 340
 341                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 342                 procdir[sizeof(procdir)-1] = '\0';
 343
 344                 f = open(procdir, O_RDONLY);
 345                 if (f == -1)
 346                         continue;
 347
 348                 len = read(f, line, sizeof(line)-1);
 349                 close(f);
 350
 351                 if (len <= 0)
 352                         continue;
 353                 else
 354                         line[len] = '\0';
 355
 356                 /* skip ugly program name */
 357                 pos = strrchr(line, ')') + 2;
 358                 if (pos == NULL)
 359                         continue;
 360
 361                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 362                         continue;
 363
 364                 /* count only processes in our session */
 365                 if (sess != session)
 366                         continue;
 367
 368                 /* count only running, no sleeping processes */
 369                 if (state != 'R')
 370                         continue;
 371
 372                 running++;
 373                 if (limit > 0 && running >= limit)
 374                         break;
 375         }
 376         closedir(dir);
 377
 378         return running;
 379 }
 380
 381 static int compare_devpath(const char *running, const char *waiting)
 382 {
 383         int i;
 384
 385         for (i = 0; i < PATH_SIZE; i++) {
 386                 /* identical device event found */
 387                 if (running[i] == '\0' && waiting[i] == '\0')
 388                         return 1;
 389
 390                 /* parent device event found */
 391                 if (running[i] == '\0' && waiting[i] == '/')
 392                         return 2;
 393
 394                 /* child device event found */
 395                 if (running[i] == '/' && waiting[i] == '\0')
 396                         return 3;
 397
 398                 /* no matching event */
 399                 if (running[i] != waiting[i])
 400                         break;
 401         }
 402
 403         return 0;
 404 }
 405
 406 /* returns still running task for the same device, its parent or its physical device */
 407 static int running_with_devpath(struct uevent_msg *msg, int limit)
 408 {
 409         struct uevent_msg *loop_msg;
 410         int childs_count = 0;
 411
 412         list_for_each_entry(loop_msg, &running_list, node) {
 413                 if (limit && childs_count++ > limit) {
 414                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 415                         return 1;
 416                 }
 417
 418                 /* return running parent/child device event */
 419                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 420                         dbg("%llu, child device event still running %llu (%s)",
 421                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 422                         return 2;
 423                 }
 424
 425                 /* return running physical device event */
 426                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 427                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 428                                 dbg("%llu, physical device event still running %llu (%s)",
 429                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 430                                 return 3;
 431                         }
 432         }
 433
 434         return 0;
 435 }
 436
 437 /* exec queue management routine executes the events and serializes events in the same sequence */
 438 static void msg_queue_manager(void)
 439 {
 440         struct uevent_msg *loop_msg;
 441         struct uevent_msg *tmp_msg;
 442         int running;
 443
 444         if (list_empty(&exec_list))
 445                 return;
 446
 447         running = running_processes();
 448         dbg("%d processes runnning on system", running);
 449         if (running < 0)
 450                 running = max_childs_running;
 451
 452         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 453                 /* check running processes in our session and possibly throttle */
 454                 if (running >= max_childs_running) {
 455                         running = running_processes_in_session(sid, max_childs_running+10);
 456                         dbg("at least %d processes running in session", running);
 457                         if (running >= max_childs_running) {
 458                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 459                                 return;
 460                         }
 461                 }
 462
 463                 /* don't run two processes for the same devpath and wait for the parent*/
 464                 if (running_with_devpath(loop_msg, max_childs)) {
 465                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 466                         continue;
 467                 }
 468
 469                 /* move event to run list */
 470                 list_move_tail(&loop_msg->node, &running_list);
 471                 udev_event_run(loop_msg);
 472                 running++;
 473                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 474         }
 475 }
 476
 477 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 478 {
 479         int bufpos;
 480         int i;
 481         struct uevent_msg *msg;
 482         int major = 0;
 483         int minor = 0;
 484
 485         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 486         if (msg == NULL)
 487                 return NULL;
 488         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 489
 490         /* copy environment buffer and reconstruct envp */
 491         memcpy(msg->envbuf, buf, buf_size);
 492         bufpos = 0;
 493         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 494                 int keylen;
 495                 char *key;
 496
 497                 key = &msg->envbuf[bufpos];
 498                 keylen = strlen(key);
 499                 msg->envp[i] = key;
 500                 bufpos += keylen + 1;
 501                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 502
 503                 /* remember some keys for further processing */
 504                 if (strncmp(key, "ACTION=", 7) == 0)
 505                         msg->action = &key[7];
 506                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 507                         msg->devpath = &key[8];
 508                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 509                         msg->subsystem = &key[10];
 510                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 511                         msg->seqnum = strtoull(&key[7], NULL, 10);
 512                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 513                         msg->physdevpath = &key[12];
 514                 else if (strncmp(key, "MAJOR=", 6) == 0)
 515                         major = strtoull(&key[6], NULL, 10);
 516                 else if (strncmp(key, "MINOR=", 6) == 0)
 517                         minor = strtoull(&key[6], NULL, 10);
 518                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 519                         msg->timeout = strtoull(&key[8], NULL, 10);
 520         }
 521         msg->devt = makedev(major, minor);
 522         msg->envp[i++] = "UDEVD_EVENT=1";
 523         msg->envp[i] = NULL;
 524
 525         if (msg->devpath == NULL || msg->action == NULL) {
 526                 info("DEVPATH or ACTION missing, ignore message");
 527                 free(msg);
 528                 return NULL;
 529         }
 530
 531         return msg;
 532 }
 533
 534 /* receive the udevd message from userspace */
 535 static struct uevent_msg *get_udevd_msg(void)
 536 {
 537         static struct udevd_msg usend_msg;
 538         struct uevent_msg *msg;
 539         ssize_t size;
 540         struct msghdr smsg;
 541         struct cmsghdr *cmsg;
 542         struct iovec iov;
 543         struct ucred *cred;
 544         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 545         int envbuf_size;
 546         int *intval;
 547
 548         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 549         iov.iov_base = &usend_msg;
 550         iov.iov_len = sizeof(struct udevd_msg);
 551
 552         memset(&smsg, 0x00, sizeof(struct msghdr));
 553         smsg.msg_iov = &iov;
 554         smsg.msg_iovlen = 1;
 555         smsg.msg_control = cred_msg;
 556         smsg.msg_controllen = sizeof(cred_msg);
 557
 558         size = recvmsg(udevd_sock, &smsg, 0);
 559         if (size <  0) {
 560                 if (errno != EINTR)
 561                         err("unable to receive user udevd message: %s", strerror(errno));
 562                 return NULL;
 563         }
 564         cmsg = CMSG_FIRSTHDR(&smsg);
 565         cred = (struct ucred *) CMSG_DATA(cmsg);
 566
 567         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 568                 err("no sender credentials received, message ignored");
 569                 return NULL;
 570         }
 571
 572         if (cred->uid != 0) {
 573                 err("sender uid=%i, message ignored", cred->uid);
 574                 return NULL;
 575         }
 576
 577         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 578                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 579                 return NULL;
 580         }
 581
 582         switch (usend_msg.type) {
 583         case UDEVD_UEVENT_UDEVSEND:
 584         case UDEVD_UEVENT_INITSEND:
 585                 info("udevd event message received");
 586                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 587                 dbg("envbuf_size=%i", envbuf_size);
 588                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 589                 if (msg == NULL)
 590                         return NULL;
 591                 msg->type = usend_msg.type;
 592                 return msg;
 593         case UDEVD_STOP_EXEC_QUEUE:
 594                 info("udevd message (STOP_EXEC_QUEUE) received");
 595                 stop_exec_q = 1;
 596                 break;
 597         case UDEVD_START_EXEC_QUEUE:
 598                 info("udevd message (START_EXEC_QUEUE) received");
 599                 stop_exec_q = 0;
 600                 msg_queue_manager();
 601                 break;
 602         case UDEVD_SET_LOG_LEVEL:
 603                 intval = (int *) usend_msg.envbuf;
 604                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 605                 udev_log_priority = *intval;
 606                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 607                 putenv(udev_log);
 608                 break;
 609         case UDEVD_SET_MAX_CHILDS:
 610                 intval = (int *) usend_msg.envbuf;
 611                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 612                 max_childs = *intval;
 613                 break;
 614         case UDEVD_RELOAD_RULES:
 615                 info("udevd message (RELOAD_RULES) received");
 616                 reload_config = 1;
 617                 break;
 618         default:
 619                 dbg("unknown message type");
 620         }
 621         return NULL;
 622 }
 623
 624 /* receive the kernel user event message and do some sanity checks */
 625 static struct uevent_msg *get_netlink_msg(void)
 626 {
 627         struct uevent_msg *msg;
 628         int bufpos;
 629         ssize_t size;
 630         static char buffer[UEVENT_BUFFER_SIZE+512];
 631         char *pos;
 632
 633         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 634         if (size <  0) {
 635                 if (errno != EINTR)
 636                         err("unable to receive kernel netlink message: %s", strerror(errno));
 637                 return NULL;
 638         }
 639
 640         if ((size_t)size > sizeof(buffer)-1)
 641                 size = sizeof(buffer)-1;
 642         buffer[size] = '\0';
 643         dbg("uevent_size=%zi", size);
 644
 645         /* start of event payload */
 646         bufpos = strlen(buffer)+1;
 647         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 648         if (msg == NULL)
 649                 return NULL;
 650         msg->type = UDEVD_UEVENT_NETLINK;
 651
 652         /* validate message */
 653         pos = strchr(buffer, '@');
 654         if (pos == NULL) {
 655                 err("invalid uevent '%s'", buffer);
 656                 free(msg);
 657                 return NULL;
 658         }
 659         pos[0] = '\0';
 660
 661         if (msg->action == NULL) {
 662                 info("no ACTION in payload found, skip event '%s'", buffer);
 663                 free(msg);
 664                 return NULL;
 665         }
 666
 667         if (strcmp(msg->action, buffer) != 0) {
 668                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 669                 free(msg);
 670                 return NULL;
 671         }
 672
 673         return msg;
 674 }
 675
 676 static void asmlinkage sig_handler(int signum)
 677 {
 678         switch (signum) {
 679                 case SIGINT:
 680                 case SIGTERM:
 681                         udev_exit = 1;
 682                         break;
 683                 case SIGCHLD:
 684                         /* set flag, then write to pipe if needed */
 685                         sigchilds_waiting = 1;
 686                         break;
 687                 case SIGHUP:
 688                         reload_config = 1;
 689                         break;
 690         }
 691
 692         /* write to pipe, which will wakeup select() in our mainloop */
 693         write(signal_pipe[WRITE_END], "", 1);
 694 }
 695
 696 static void udev_done(int pid, int exitstatus)
 697 {
 698         /* find msg associated with pid and delete it */
 699         struct uevent_msg *msg;
 700
 701         list_for_each_entry(msg, &running_list, node) {
 702                 if (msg->pid == pid) {
 703                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 704                              exitstatus, time(NULL) - msg->queue_time);
 705                         msg->exitstatus = exitstatus;
 706                         msg_queue_delete(msg);
 707
 708                         /* there may be events waiting with the same devpath */
 709                         run_exec_q = 1;
 710                         return;
 711                 }
 712         }
 713 }
 714
 715 static void reap_sigchilds(void)
 716 {
 717         pid_t pid;
 718         int status;
 719
 720         while (1) {
 721                 pid = waitpid(-1, &status, WNOHANG);
 722                 if (pid <= 0)
 723                         break;
 724                 if (WIFEXITED(status))
 725                         status = WEXITSTATUS(status);
 726                 else if (WIFSIGNALED(status))
 727                         status = WTERMSIG(status) + 128;
 728                 else
 729                         status = 0;
 730                 udev_done(pid, status);
 731         }
 732 }
 733
 734 static int init_udevd_socket(void)
 735 {
 736         struct sockaddr_un saddr;
 737         const int buffersize = 16 * 1024 * 1024;
 738         socklen_t addrlen;
 739         const int feature_on = 1;
 740         int retval;
 741
 742         memset(&saddr, 0x00, sizeof(saddr));
 743         saddr.sun_family = AF_LOCAL;
 744         /* use abstract namespace for socket path */
 745         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 746         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 747
 748         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 749         if (udevd_sock == -1) {
 750                 err("error getting socket: %s", strerror(errno));
 751                 return -1;
 752         }
 753
 754         /* set receive buffersize */
 755         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 756
 757         /* the bind takes care of ensuring only one copy running */
 758         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 759         if (retval < 0) {
 760                 err("bind failed: %s", strerror(errno));
 761                 return -1;
 762         }
 763
 764         /* enable receiving of the sender credentials */
 765         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 766
 767         return 0;
 768 }
 769
 770 static int init_uevent_netlink_sock(void)
 771 {
 772         struct sockaddr_nl snl;
 773         const int buffersize = 16 * 1024 * 1024;
 774         int retval;
 775
 776         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 777         snl.nl_family = AF_NETLINK;
 778         snl.nl_pid = getpid();
 779         snl.nl_groups = 0xffffffff;
 780
 781         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 782         if (uevent_netlink_sock == -1) {
 783                 err("error getting socket: %s", strerror(errno));
 784                 return -1;
 785         }
 786
 787         /* set receive buffersize */
 788         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 789
 790         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 791         if (retval < 0) {
 792                 err("bind failed: %s", strerror(errno));
 793                 close(uevent_netlink_sock);
 794                 uevent_netlink_sock = -1;
 795                 return -1;
 796         }
 797         return 0;
 798 }
 799
 800 int main(int argc, char *argv[], char *envp[])
 801 {
 802         int retval;
 803         int fd;
 804         struct sigaction act;
 805         fd_set readfds;
 806         const char *value;
 807         int daemonize = 0;
 808         int i;
 809         int rc = 0;
 810         int maxfd;
 811
 812         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 813         fd = open("/dev/null", O_RDWR);
 814         if (fd >= 0) {
 815                 if (fd != STDIN_FILENO)
 816                         dup2(fd, STDIN_FILENO);
 817                 if (fd != STDOUT_FILENO)
 818                         dup2(fd, STDOUT_FILENO);
 819                 if (fd != STDERR_FILENO)
 820                         dup2(fd, STDERR_FILENO);
 821                 if (fd > STDERR_FILENO)
 822                         close(fd);
 823         }
 824
 825         logging_init("udevd");
 826         if (fd < 0)
 827                 err("fatal, could not open /dev/null: %s", strerror(errno));
 828
 829         udev_config_init();
 830         dbg("version %s", UDEV_VERSION);
 831
 832         if (getuid() != 0) {
 833                 err("need to be root, exit");
 834                 goto exit;
 835         }
 836
 837         /* parse commandline options */
 838         for (i = 1 ; i < argc; i++) {
 839                 char *arg = argv[i];
 840                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 841                         info("will daemonize");
 842                         daemonize = 1;
 843                 }
 844                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 845                         info("will not execute events until START_EXEC_QUEUE is received");
 846                         stop_exec_q = 1;
 847                 }
 848         }
 849
 850         /* init sockets to receive events */
 851         if (init_udevd_socket() < 0) {
 852                 if (errno == EADDRINUSE) {
 853                         err("another udevd running, exit");
 854                         rc = 1;
 855                 } else {
 856                         err("error initializing udevd socket: %s", strerror(errno));
 857                         rc = 2;
 858                 }
 859                 goto exit;
 860         }
 861
 862         if (init_uevent_netlink_sock() < 0) {
 863                 err("uevent socket not available");
 864                 rc = 3;
 865                 goto exit;
 866         }
 867
 868         /* parse the rules and keep it in memory */
 869         sysfs_init();
 870         udev_rules_init(&rules, 1);
 871
 872         if (daemonize) {
 873                 pid_t pid;
 874
 875                 pid = fork();
 876                 switch (pid) {
 877                 case 0:
 878                         dbg("daemonized fork running");
 879                         break;
 880                 case -1:
 881                         err("fork of daemon failed: %s", strerror(errno));
 882                         rc = 4;
 883                         goto exit;
 884                 default:
 885                         dbg("child [%u] running, parent exits", pid);
 886                         goto exit;
 887                 }
 888         }
 889
 890         /* set scheduling priority for the daemon */
 891         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 892
 893         chdir("/");
 894         umask(022);
 895
 896         /* become session leader */
 897         sid = setsid();
 898         dbg("our session is %d", sid);
 899
 900         /* OOM_DISABLE == -17 */
 901         fd = open("/proc/self/oom_adj", O_RDWR);
 902         if (fd < 0)
 903                 err("error disabling OOM: %s", strerror(errno));
 904         else {
 905                 write(fd, "-17", 3);
 906                 close(fd);
 907         }
 908
 909         /* setup signal handler pipe */
 910         retval = pipe(signal_pipe);
 911         if (retval < 0) {
 912                 err("error getting pipes: %s", strerror(errno));
 913                 goto exit;
 914         }
 915         retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
 916         if (retval < 0) {
 917                 err("error fcntl on read pipe: %s", strerror(errno));
 918                 goto exit;
 919         }
 920         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
 921         if (retval < 0) {
 922                 err("error fcntl on write pipe: %s", strerror(errno));
 923                 goto exit;
 924         }
 925
 926         /* set signal handlers */
 927         memset(&act, 0x00, sizeof(struct sigaction));
 928         act.sa_handler = (void (*)(int)) sig_handler;
 929         sigemptyset(&act.sa_mask);
 930         act.sa_flags = SA_RESTART;
 931         sigaction(SIGINT, &act, NULL);
 932         sigaction(SIGTERM, &act, NULL);
 933         sigaction(SIGCHLD, &act, NULL);
 934         sigaction(SIGHUP, &act, NULL);
 935
 936         /* watch rules directory */
 937         inotify_fd = inotify_init();
 938         if (inotify_fd > 0)
 939                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 940
 941         /* maximum limit of forked childs */
 942         value = getenv("UDEVD_MAX_CHILDS");
 943         if (value)
 944                 max_childs = strtoul(value, NULL, 10);
 945         else
 946                 max_childs = UDEVD_MAX_CHILDS;
 947         info("initialize max_childs to %u", max_childs);
 948
 949         /* start to throttle forking if maximum number of _running_ childs is reached */
 950         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 951         if (value)
 952                 max_childs_running = strtoull(value, NULL, 10);
 953         else
 954                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 955         info("initialize max_childs_running to %u", max_childs_running);
 956
 957         /* clear environment for forked event processes */
 958         clearenv();
 959
 960         /* export log_priority , as called programs may want to follow that setting */
 961         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 962         putenv(udev_log);
 963
 964         maxfd = udevd_sock;
 965         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
 966         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
 967         maxfd = UDEV_MAX(maxfd, inotify_fd);
 968
 969         while (!udev_exit) {
 970                 struct uevent_msg *msg;
 971                 int fdcount;
 972
 973                 FD_ZERO(&readfds);
 974                 FD_SET(signal_pipe[READ_END], &readfds);
 975                 FD_SET(udevd_sock, &readfds);
 976                 FD_SET(uevent_netlink_sock, &readfds);
 977                 if (inotify_fd > 0)
 978                         FD_SET(inotify_fd, &readfds);
 979
 980                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
 981                 if (fdcount < 0) {
 982                         if (errno != EINTR)
 983                                 err("error in select: %s", strerror(errno));
 984                         continue;
 985                 }
 986
 987                 /* get user socket message */
 988                 if (FD_ISSET(udevd_sock, &readfds)) {
 989                         msg = get_udevd_msg();
 990                         if (msg)
 991                                 msg_queue_insert(msg);
 992                 }
 993
 994                 /* get kernel netlink message */
 995                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
 996                         msg = get_netlink_msg();
 997                         if (msg)
 998                                 msg_queue_insert(msg);
 999                 }
1000
1001                 /* received a signal, clear our notification pipe */
1002                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1003                         char buf[256];
1004
1005                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1006                 }
1007
1008                 /* rules directory inotify watch */
1009                 if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
1010                         int nbytes;
1011
1012                         /* discard all possible events, we can just reload the config */
1013                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1014                                 char *buf;
1015
1016                                 reload_config = 1;
1017                                 buf = malloc(nbytes);
1018                                 if (!buf) {
1019                                         err("error getting buffer for inotify, disable watching");
1020                                         close(inotify_fd);
1021                                         inotify_fd = -1;
1022                                 }
1023                                 read(inotify_fd, buf, nbytes);
1024                                 free(buf);
1025                         }
1026                 }
1027
1028                 /* rules changed, set by inotify or a signal*/
1029                 if (reload_config) {
1030                         reload_config = 0;
1031                         udev_rules_cleanup(&rules);
1032                         udev_rules_init(&rules, 1);
1033                 }
1034
1035                 /* forked child has returned */
1036                 if (sigchilds_waiting) {
1037                         sigchilds_waiting = 0;
1038                         reap_sigchilds();
1039                 }
1040
1041                 if (run_exec_q) {
1042                         run_exec_q = 0;
1043                         if (!stop_exec_q)
1044                                 msg_queue_manager();
1045                 }
1046         }
1047
1048 exit:
1049         udev_rules_cleanup(&rules);
1050         sysfs_cleanup();
1051
1052         if (signal_pipe[READ_END] > 0)
1053                 close(signal_pipe[READ_END]);
1054         if (signal_pipe[WRITE_END] > 0)
1055                 close(signal_pipe[WRITE_END]);
1056
1057         if (udevd_sock > 0)
1058                 close(udevd_sock);
1059         if (inotify_fd > 0)
1060                 close(inotify_fd);
1061         if (uevent_netlink_sock > 0)
1062                 close(uevent_netlink_sock);
1063
1064         logging_close();
1065
1066         return rc;
1067 }